Horizontal Continuous Casting Machine

— Horizontal Continuous Casting Machine: Withdrawal Cycle, Die and Shell

A horizontal continuous casting machine turns molten metal into solid rod, tube, bar or strip: the metal flows through a water-cooled die and is withdrawn along the same axis. It is bought for a withdrawal cycle, not a casting speed: the strand moves in strokes with a pause, so the average speed is just stroke times frequency. That cycle decides whether the shell tears, how thick it leaves, and how much run-out the site needs.The line has four working blocks: a melting furnace and a holding furnace holding a steady level and temperature; a refractory break ring fixing where solidification begins and a graphite die shaping the section; a withdrawal system with its force instrumented, since that trend reports die wear; and a synchronous saw or shear cutting to length.It casts copper alloys — brasses, bronzes, cupro-nickels, nickel silvers — plus zinc, aluminium, silver, gold and iron, producing round rod, hollow bar or tube, strip or flat section for drawing or rolling.

Product Overview

This is a semi-finished producer rather than a finishing machine: its output is a long product — rod, bar, tube, hollow profile or strip — for a drawing bench, an extruder, a rolling mill or a machining line, and the horizontal arrangement is chosen because the strand is never bent while it is still soft.

The rest of the machine’s engineering follows from one event: the shell that forms at the entry of the die has to be strong enough to survive being pulled, and the friction between that shell and the die has to be released before it is pulled again. That is why the withdrawal is intermittent, and why the cycle — a stroke, a pause and, in the pushback variant, a short reverse motion — is the machine’s real control variable. A published specification in this class illustrates how explicit this can be made: 40 to 80 mm of stroke, 0.2 to 0.25 seconds of stroke time, 0.6 to 0.75 seconds of pause, 60 to 75 cycles per minute, and a resulting casting velocity of 4.0 to 5.0 metres per minute for the grade actually cast.

The economics are decided by two lengths. The first is the die, whose life is measured in tonnes of metal passed: it wears by thermal cycling and abrasion, and its condition is visible in the withdrawal force trend. The second is the run-out — the distance the strand travels before it is self-supporting enough to be supported, cut or coiled — which is the average casting speed multiplied by the solidification time, and therefore a consequence of the cycle and the alloy rather than a matter of taste. A horizontal line pays for that length in plan; a vertical machine pays for the same solidification distance in elevation and in the pit beneath it.

Two things this machine does not do are worth stating plainly. It does not refine: the composition that leaves is the composition that arrived, and its contribution to quality is structural — grain size, directionality, soundness of the section — not chemical. And it does not finish: it makes the feedstock for the operation that follows, and the tolerances it holds are the tolerances of a casting. Both statements matter here more than on most equipment pages, because what the section is for, what tolerance the downstream operation needs and what the alloy’s freezing behaviour will allow all have to be settled before the die is made.

Product Core Selling Points

The withdrawal cycle is quoted as three numbers, and the casting speed is shown as their product. A published specification in this class states 40 to 80 mm of stroke, 60 to 75 cycles per minute, 0.2 to 0.25 seconds of stroke time and 0.6 to 0.75 seconds of pause, and the arithmetic closes: 40 mm at 60 per minute is 2.4 metres per minute, 80 mm at 75 is 6.0. Because the cycle is written down, a second quotation can be compared with ours on the same duty instead of on the same adjective.
The duty fraction of the cycle is stated, because it is what the drive and the cooling see. Those published figures put the strand in motion for a quarter of the cycle, so the instantaneous rate is about four times the average — 12 to 19 metres per minute against a quoted 4.0 to 5.0. The drive, rolls, clamps and secondary cooling are sized on the stroke rather than the mean.
The break ring is specified by material and by replacement trigger, and it appears as a consumable line. It fixes the plane at which solidification begins, and a published specification in this class names boron nitride for it. We state the material, the reason it was chosen against the alloy’s tendency to wet or attack it, and the measurable condition that triggers replacement.
The die is specified as a grade with property values, and the life is quoted in tonnes. Published suppliers in this field sell graphite by grade, but no machine page read here states grain size, density, gas permeability, ash and thermal conductivity, or a life against them. We state those values, which set the thermal path and the friction at the interface, and quote life as tonnes of metal passed per die, because a published figure of over 500 hours describes the site’s calendar rather than the die.
The cooling circuit is specified as a permitted temperature rise, not a flow rate. Removing the latent heat and superheat from copper is roughly 220 kilojoules per kilogram at a 30 K superheat, about 5.3 kilograms of water per kilogram of metal at a 10 K rise and 2.6 at 20 K. The circuit is stated as inlet temperature, permitted rise and flow and is zoned, because the local flux at the start plane is several times the average and it is the local wall temperature that decides whether the coolant boils.
The metallurgical length is computed from the cycle and the alloy, and quoted as a length the site must find room for. The run-out length is the average casting speed multiplied by the solidification time, and the average speed is the stroke multiplied by the frequency, so the floor length of a horizontal line is an output of the cycle rather than a layout accident. A longer stroke shortens it and a longer freezing range lengthens it.
The oxygen figure is offered as a measurement with a method and a point, not as an adjective. The oxygen-free grades are defined by an upper limit of 0.001 per cent for Cu-OF and 0.0005 per cent for the electronic grade, and published figures for the vertical routes in this field sit at 1 to 3 ppm, while no machine page found here states an achievable value for a horizontal line. We therefore treat the figure as a result of the whole melt path and undertake it against a stated sampling method, location and frequency, with the analysis as referee rather than the design intent.
The dimension that governs the section is named for every profile family. Diameter comes from the die bore, the bore of a hollow section from the mandrel, strip width and thickness from the die slot, and the wall of a tube is the difference between two separately tolerated dimensions. We state which element sets which dimension and how the tolerances add, because one blanket figure covering a bore, a mandrel and a slot is a promise the process does not make.
The as-cast product is positioned as the feedstock it is. The machine makes a semi-finished long product for drawing, extruding, rolling or machining, not a finished tube, wire or busbar. We name the downstream operation and size the section against its input, because a caster bought as though it were a finishing mill is the most expensive mistake available in this purchase.
The alloy list is a list of what the die, the atmosphere and the cycle can hold, with the consequence stated for each. Published practice in this field casts copper, the leaded and lead-free brasses, the tin, phosphor, manganese, silicon and aluminium bronzes, cupro-nickels, nickel silvers and the coinage and precious families, with grey and white cast irons in the same class of machine. We state for each family what it does to the die, the break ring and the gas path rather than printing a list of names.
The changeover is planned as a sequence rather than offered as a number. A published die change figure here is about fifteen minutes and, on one page, five minutes, and both refer to the die alone. An alloy change also displaces the heel in the holding furnace and launder, may change the die, mandrel and break ring, re-establishes the die’s thermal steady state and takes the first lengths as scrap, so we quote the transition metal and downtime that follow from the sequence.
The machine’s wear is detected by the pull force rather than by the calendar. A rising withdrawal force at an unchanged cycle is the die telling the plant that its bore has changed, and a falling force with a rising die temperature says the opposite. The drive is instrumented for that trend, so a die, a break ring, a set of rolls or a nozzle is replaced on a measurement instead of a schedule.
The horizontal layout is offered for the reasons it is actually better, and the ones it is not better for are named. Withdrawing in a straight line imposes no bending strain on a shell that may still be mushy, which is what makes crack-sensitive alloys and hollow sections practical, and it removes the pit, the tower and the bending radius. It does not remove the need for run-out length, and it does not beat a vertical route on a single high-tonnage alloy where floor space is dearer than height.
The work that does not belong on a horizontal machine is refused in writing. A finished-product tolerance with no downstream operation; an alloy with no measured composition and no stated oxygen target; a tonnage at which the required run-out length makes the plan impossible; a leaded grade in a lead-free market with no die qualification; a duty with no route for the transition metal, the dross or the off-gas; and a requirement for discrete cast ingots, which is a different machine.

Application Scenarios

A horizontal continuous casting machine is bought wherever a foundry or a rolling shop needs its own supply of a long, straight semi-finished section in a non-ferrous alloy, in a volume too small or too varied to buy from a billet producer. Output in each case is the semi-finished product as it leaves the line, and each scenario fixes the alloy, the section geometry, the tolerance and the cycle.

Wire rod for a drawing bench. Oxygen-free or deoxidised copper rod cast for drawing down to wire, so the section has to survive drawing without breaking and arrive with a conductivity the annealing schedule does not have to repair; published diameters start at 8 mm and run to about 30 mm. Output: a coiled or straight-length rod measured for conductivity and oxygen on the coil, whose as-cast surface is the die’s own surface transferred to the metal.
Free-cutting brass rod for machining. Rod for fittings, valves, sanitary ware and connectors, where the alloy is chosen for machinability and the section is drawn or extruded afterwards. Output: a rod whose composition — including whether it is a leaded or a lead-free grade — is fixed before the die is ordered, because published die suppliers state that the lead-free substitutions are aggressive to graphite.
Bronze bar and bushing stock. Tin, phosphor, manganese and aluminium bronzes cast as round or hollow bar for bearings, bushes, wear plates and pump and valve components, Output: a bar on the drawing’s input size, with the bore formed by the mandrel and the wall stated as the difference between two separately tolerated dimensions.
Copper tube for refrigeration and HVAC. The clearest case for the horizontal layout, because the section is hollow and the strand cannot be bent over a radius while its wall is still soft; published ranges quote outside diameters from 10 mm to 250 mm with walls from 0.5 mm to 15 mm. Output: a straight or coiled tube whose outside diameter comes from the die bore and whose inside diameter comes from the mandrel, then going to drawing and annealing.
Cupro-nickel and nickel silver sections. Alloys for heat exchangers, desalination tube, coinage and hardware, cast in modest tonnages across several grades. Output: a section whose alloy sequence has been planned rather than improvised, because each change costs transition metal and a mixed heat in this group is a rejected heat.
Aluminium bronze, manganese bronze and gunmetal bar. Higher-strength copper alloys for marine hardware, propellers, valves and heavy-duty bushes. Output: a bar whose surface condition is established at the die rather than by a later dressing, qualified against the application’s mechanical property requirement rather than a conductivity figure.
Strip and busbar. Flat product cast through a slot die and then rolled or finished, published at thicknesses from about 10 mm to 20 mm and at widths from a few tens of millimetres on compact machines to the metre scale on plant-scale casters. Output: a strip whose width and thickness are both die-slot results, so the casting tolerance and the rolling reduction have to be planned together.
In-house remelt of clean process scrap. A shop that already generates clean, sorted copper or copper-alloy scrap — stripped conductor, punched busbar offcuts, dried briquetted swarf, rejected castings — and wants to convert it into a saleable section rather than sell it; the route that produces that clean fraction is described under non-ferrous metal extraction equipment. Output: a section whose chemistry is a blend, so the analysis has to be made on the melt before the die is set.
Zinc and zinc-alloy rod and strip. Rod and strip for anodes, sacrificial components and hardware, in alloys whose low melting temperature shortens the thermal gradient the break ring has to hold. Output: a section cast at a much lower superheat than the copper family, which reduces the heat to be removed and therefore changes the cycle, not only the alloy.
Iron and white-iron bar stock. Cast and white cast iron bar and sections for rolls, wear parts and mill liners, published among the families cast through graphite moulds. Output: a section whose die and break ring are specified for a temperature far above the copper family’s and whose cycle is slower, because the shell that must survive the pull has to be thicker.
Coinage, precious-metal and special-alloy sections. Small-tonnage multi-grade work — coinage alloys, silver- and gold-bearing alloys, controlled-expansion and resistance alloys — where the machine’s value is changing grade without a billet purchase and each heat’s identity has to be preserved. Output: a section with a declared composition per heat, in a shop where a mixed grade is unsellable.
A site that has floor but no height. A brownfield building with a low eaves line, no pit and no room for a bending radius. Output: a line whose run-out length is bought as plan area, stated as a number the site has to find room for rather than discovered during erection.
A foundry that wants to stop buying billet. A shop that currently buys billet or rod and pays the margin and the freight on it; where its own melt and scrap are controlled, the caster converts them into the same section it was buying. Output: a section produced from the shop’s own metal, whose value depends on the analysis being made before casting rather than after a rejection.
Not an application for this machine. Discrete cast ingots of a defined weight and shape, which is a different machine, described under vacuum ingot casting machine. A finished drawn, annealed or bright product with no downstream operation behind it. An alloy with no measured composition and no stated oxygen or property target. A tonnage at which the run-out length a horizontal machine needs makes the plan unaffordable. A copper duty whose real product is cathode-grade metal from solution, which belongs to the electrowinning and electrolysis line and, at the cell level, to a copper electrolytic cell. A leaded grade in a lead-free market with no die qualification. A site with no route for the transition metal, the dross or the off-gas. And any duty whose melt is not controlled, because a caster is not a refiner and an uncontrolled melt is fixed upstream — in a smelting furnace, or where more specialised melting is required in a high frequency smelting furnace or an oxygen-enriched bottom-blown furnace. Output: a written refusal naming the mechanism and the upstream or downstream change that would make the duty treatable.

Applicable Raw Materials

The feed to a horizontal continuous casting machine is a melt, and specifying a melt means stating five properties rather than an alloy name: the composition, the superheat above the liquidus, the gas content — dissolved oxygen above all — the cleanliness as dross and inclusion load, and the consistency of the charge in form and temperature. Those five decide the die grade, the break ring material, the atmosphere at the die and the surface quality.

Electrolytic copper cathode, Grade A. The canonical feed for the oxygen-free and deoxidised copper routes: flat plates, dry, with a known analysis and a low residual oxygen content, melted and transferred with the surface protected. Output: a melt whose oxygen content is still controlled at the point of transfer.
Clean, sorted process scrap from the plant’s own operations. Stripped conductor, punched busbar offcuts, extruded and drawn offcuts and dry briquetted swarf, all with a known and reasonably stable analysis. Output: a melt whose two variables are surface area and coating history, because organics and moisture produce gas at the wrong moment.
Purchased copper and copper-alloy ingot. Bought ingot or billet remelted where the shop has no melting and refining upstream, arriving with a supplier’s analysis and remelted without refining. Output: a melt whose composition is inherited, so the only chemistry the caster controls is what it adds or lets leave at the surface.
Leaded free-cutting brass. The machining-rod grades, cast and then drawn or extruded, with the lead deliberately present because it makes the chips break; published practice casts these grades through graphite dies. Output: a melt that pours and casts predictably, and a die whose service life is the reference against which any substitution is measured.
Lead-free free-cutting brass. The bismuth and silicon substitutions that replace lead where leaded grades are being withdrawn, cast in the same machine but not through the same die without qualification; published die suppliers describe these alloys as very aggressive and offer coated graphite dies for them. Output: a melt chemically different at the die interface, so the die specification and its life are re-established rather than transferred.
Tin, phosphor, manganese, silicon and gunmetal bronzes. Cast as solid and hollow bar for bearings, bushes, wear parts and pump and valve bodies, with the aluminium bronzes and the aluminium-tin alloys in the same graphite-die family. Output: a melt whose oxide-forming tendency and freezing range set the superheat and the cycle, stated for the grade rather than assumed from another bronze.
Cupro-nickel and nickel silver. Alloys for condenser and heat-exchanger tube, coinage and hardware, in which the nickel content changes the thermal conductivity of the solid and the rate of shell growth. Output: a melt whose lower thermal conductivity means a slower shell and a longer pause than the same section in pure copper.
Zinc and zinc alloys. Rod, strip and anode stock cast from a melt whose liquidus is far below the copper family’s, which reduces the superheat to be removed and the temperature the break ring sees. Output: a melt whose casting temperature changes the thermal duty of the whole line, and therefore the cooling and the cycle.
Aluminium and aluminium alloys. Rod and strip for conductors, profiles and hardware, published in this class of machine alongside the copper family. Output: a melt whose affinity for oxygen makes the metal surface and the transfer path the governing items, so the shroud or blanket is specified rather than optional.
Cast iron and white cast iron. Bar and sections for rolls, wear parts and mill liners, cast through graphite in the same family of machine and at a temperature well above the copper family’s. Output: a melt whose superheat and shell growth rate set a slower cycle and a differently specified die and break ring.
Silver, gold, coinage and resistance alloys. Small-tonnage, high-value, multi-grade work in which each heat has to be identified and the grade sequence planned so that one heat’s residual heel does not contaminate the next. Output: a melt whose identity and analytical record travel with the section, in a shop where a blended heat is a write-off.
In-house returns, runners and rejected castings. Clean internal returns remelted rather than sold, with a known analysis but a surface condition that varies from clean to heavily oxidised. Output: a melt whose gas content depends on how the returns were stored, which is why charge cleanliness is a specification line and not housekeeping.
Feed refused at the holding furnace. A charge whose composition was not measured before the die was set; mixed or wet scrap whose chemistry cannot be established and whose moisture will produce gas at the die; an alloy whose freezing range has not been checked against the section; a lead-free substitution with no die qualification; a charge carrying coatings or moisture into a machine with no extraction; an oxygen target set without a sampling method and point; and any duty in which the caster is expected to act as the refining step. Output: a written refusal naming the mechanism and the upstream change that would make the charge castable.
Feed that belongs upstream of this machine. Where the feed is not a melt but a mixed or chemically variable material — electronic assemblies, coated cable, foundry residue, anode slime, refinery intermediate — turning it into a controlled melt belongs to the smelting, converting and refining operations and not to the caster; one such route is described under lead-copper anode slime converter. Output: a handover to the operation that owns that feed, with the point at which the caster’s own feed begins written down.

Finished Products

What leaves a horizontal continuous casting machine is a section, a set of measured numbers and a consumable record. The section is what the customer buys, the numbers make it buyable and rejectable, and the consumable record turns the running cost into a figure rather than an experience. The last two entries below are the things this machine does not produce.

Cast round rod and bar. A round section drawn out of the die at a diameter set by the die bore and cut to length or coiled to weight; published ranges run from single-figure millimetres, about 8 mm on the oxygen-free routes, up to 200 mm and beyond. Output: a rod whose diameter is a die-bore result, whose length is a cut result and whose surface is the die’s own surface transferred to the metal.
Cast hollow bar, tube and hollow profile. Outside diameter from the die bore and inside diameter from a mandrel, in the copper, cupro-nickel and bronze families; published ranges for the tube duty quote outside diameters from 10 mm to 250 mm with walls from 0.5 mm to 15 mm. Output: a straight or coiled hollow section whose wall is the difference between two separately tolerated dimensions.
Cast strip, flat bar and busbar. Flat product formed through a die slot and sold as cast or passed to a rolling mill, published at thicknesses from about 10 mm to 20 mm and widths to the metre scale. Output: a strip whose width and thickness are both die-slot results.
Cast shapes and sections to a die profile. Where the machine is ordered for a profile rather than a round or a flat, the whole geometry is a die artefact and the die is the drawing. Output: a profile whose tolerance is the die’s tolerance.
A cast structure, which is a different product from a cast shape. Solidification in a die with a defined thermal gradient and withdrawal direction produces a grain size, an orientation and a soundness a mould casting does not reproduce. Output: a structure established by a micrograph and a mechanical test rather than by the shape.
A section with a named element behind each dimension. Diameter from the die bore, bore from the mandrel, width and thickness from the die slot, straightness from the run-out support and the cut, and a surface finish that is the die’s own surface transferred to the metal. Output: a dimensional and surface report naming the element each figure came from.
A composition per heat, with the analysis travelling with the section. The machine fixes the composition it is given, so the product includes the evidence: a heat number and an analysis taken before the cast. Output: a declared composition with its heat identification.
A measured oxygen figure with its method, its point and its frequency. The oxygen-free grades are defined by an upper limit of 0.001 per cent for Cu-OF and 0.0005 per cent for the electronic grade, and published values on the vertical routes in this field sit at 1 to 3 ppm. Output: an oxygen result naming the sampling point, method and analysis technique.
A measured conductivity or resistivity with its temperature and specimen. The international annealed copper standard fixes 100 per cent IACS at 0.017241 ohm square millimetre per metre, so a published band of 99 to 101 per cent corresponds to about 0.01741 down to 0.01707. Output: a conductivity figure with its measurement temperature and specimen condition stated.
A cut length, a coil or a stack, with the cut ends controlled. The synchronous saw or shear fixes the length tolerance and end condition, and the run-out table or coiler fixes how the product is presented to the next operation. Output: a length, weight or coil count with a specified cut-end quality.
A transition and off-specification record. A grade or die change produces first lengths that are not on specification. Output: a declared transition quantity with its analysis and disposition, so the metal is accounted for as product, internal return or scrap.
A consumable and campaign record. Tonnes passed per die, break ring life, withdrawal roll condition, shear blade life and secondary-cooling nozzle condition, each with the measurement that triggered replacement. Output: a consumable schedule in tonnes and cycles rather than hours.
A line baseline that makes drift visible. The withdrawal force, die and cooling temperatures, level, section and surface condition recorded at the design cycle, so the first sign of die wear or of a cooling change appears as a movement away from a recorded number. Output: a baseline file rather than a commissioning report.
Not a product of this machine — refined metal. The caster does not raise the grade or purity of what it is fed: composition enters with the melt and leaves with the section. A duty that needs metal improved rather than shaped belongs to the hydrometallurgical, electrolytic or electrowinning lines — for copper from solution, to copper electrolysis equipment — and a duty needing a discrete cast piece rather than a continuous length belongs to a gold and silver ingot casting mold rather than a caster. Output: a handover naming the operation that owns the requirement.
Not a product of this machine — a finished article, or a divided form. A drawn, annealed, bright-finished or coiled-to-tolerance product has at least one operation after the caster. A requirement for granules or shot is met by a precious metal granulator, and a requirement for powder by atomization powder making equipment, by mechanisms with nothing to do with withdrawing a shell out of a die. Output: a statement of which operation produces the finished form.

Horizontal Continuous Casting Machine Process Flow

The nine stages below are the working sequence of a horizontal continuous casting line, written at the level of the decisions that the machine forces. A horizontal line is not started by pressing the withdrawal button and watching: it is started by proving that the melt’s composition, superheat and gas content were established before the cast, that the die and break ring were assembled and preheated to the arrangement the duty needs, and that the cycle was set from the stroke, stroke time and pause rather than from a speed.

Horizontal continuous casting machine working sequence — nine stages from the melt analysis and the holding furnace to a synchronous cut and a measured cast record taken with the die, the break ring and the cycle that produced it.

Steps 1 — Melt Preparation and Melt Quality Control. Nothing about the machine is decided before the melt has been measured, because the caster fixes the composition it is given and adds structure rather than chemistry. This stage establishes the analysis of the charge before it is melted — the alloy and grade, the residual elements that matter to the section, and for the oxygen-free routes the oxygen target itself — then controls the melting so that the analysis survives: the charge is dry and sorted, the melt surface is covered or blanketed, and the transfer keeps the metal from picking up oxygen or moisture. Superheat is fixed here rather than at the die: every degree above the liquidus is heat that has to be taken out again in the die. Setting and utility input: the charge with its analysis and dryness, the alloy and grade, and the oxygen or gas target. Output: a melt whose composition, superheat and gas content are measured before the cast.

Steps 2 — Holding Furnace Temperature and Level Control. The holding furnace is what makes the caster a caster, because it decouples a batch melting operation from a continuous withdrawal that never stops for a ladle. It is the level rather than the temperature that the die feels: the metal head above the die axis is the pressure that pushes metal into the shell as it contracts, so a level that drifts is a section that drifts. The temperature is held in a band narrow enough that the superheat reaching the die does not change with time, which makes the holding power a control loop in its own right. The stage also fixes the sequence in which the furnace is emptied and refilled, because the residual heel is how one grade contaminates the next. Setting and utility input: the holding temperature and level bands with their control arrangement, the holding power available, and the alloy sequence plan. Output: a holding bath at a stated temperature and level band, an emptying and refilling sequence for grade changes, and holding power stated separately from melting power.

Steps 3 — Break Ring and Die Assembly Set-Up. This is the stage that fixes where solidification begins, and therefore the stage that fixes the section. The break ring is the refractory ring between the metal supply and the water-cooled die, and its downstream face is the plane at which the shell starts; a published specification in this class names boron nitride for the ring and states that it fixes the start of billet crystallisation, while a published patent in the same field describes rings with a boron nitride or silicon nitride skin on a zirconia, alumina or silicon carbide substrate. The die is a grade of graphite chosen against the alloy and the section: it is specified with its grain size, density, gas permeability, ash content and thermal conductivity, and the bore, the mandrel and the slot are checked against the finished section with the finishing allowance deducted. Setting and utility input: the die grade and its property values, the bore, mandrel and slot dimensions with the finishing allowance deducted, and the break ring material. Output: an assembled and preheated die, mandrel and break ring, with the shell start plane fixed by the break ring and the section verified on a dummy bar.

Steps 4 — Pull-Pause Cycle Programming and Start-Up. The cycle is the machine’s real control variable and this stage is where it is set: a stroke length, a stroke time, a pause, and in the pushback variant a short reverse motion, all of which produce a frequency and an average speed. A published specification in this class illustrates how explicit the setting can be — a stroke of 40 to 80 mm, a stroke time of 0.2 to 0.25 seconds, a pause of 0.6 to 0.75 seconds, a frequency of 60 to 75 per minute and a resulting casting velocity of 4.0 to 5.0 metres per minute for the grade actually cast — and the arithmetic is checked rather than assumed: 40 mm at 60 per minute is 2.4 metres per minute and 80 mm at 75 per minute is 6.0, so the quoted velocity is the product of the stroke and the frequency. On the same figures the strand moves for only a quarter of each cycle, so the instantaneous rate during the stroke is about four times the average, which is why the drive and the cooling are sized for the stroke and not the mean. Start-up raises the stroke in steps with the withdrawal force watched at each step, because a force that climbs rather than settles says the pause is too short for the section. Setting and utility input: the assembly from Step 3, the alloy’s solidification time, and the drive’s force and speed capability. Output: a programmed cycle stated as stroke, stroke time, pause and frequency with the average speed as their product, the duty fraction and instantaneous rate shown, and a start-up record of withdrawal force and die temperature.

Steps 5 — Mould Cooling and Shell Formation Control. The die removes the heat that turns the melt into a shell, and the way it removes it decides whether the shell exists at all. The window is narrow: too little cooling and the shell is still liquid when the stroke pulls it; too much and the shell grips the die so hard that the stroke tears it. This stage sets the cooling by a permitted temperature rise rather than a flow rate, because what has to be controlled is the local temperature of the die wall at the solidification start plane, not the bulk water temperature. Removing the latent heat and superheat from copper is roughly 220 kilojoules per kilogram at a 30 K superheat, which at a 10 K water rise is about 5.3 kilograms of water per kilogram of metal and at a 20 K rise about 2.6; the design rise is held to the lower figure because if the local flux drives the wall past the boiling point of the coolant, film boiling replaces nucleate boiling, the coefficient collapses, the die overheats and the shell breaks out. Setting and utility input: the die and jacket from Step 3, the alloy’s latent heat and specific heat, the cooling water inlet temperature and quality, and the permitted rise. Output: a zoned cooling setting stated as inlet temperature, permitted rise and flow with the heat balance shown, and alarm and trip limits.

Steps 6 — Secondary Cooling and Straight-Line Run-Out. Once the strand leaves the die it is no longer supported by the die and is not yet strong enough to be handled, so the distance it travels before anything touches it is a metallurgical requirement rather than a layout choice. This stage sets the secondary cooling — published in this class as a spray zone of water to air with an adjustable ratio, one or more zones and a defined length — to finish the solidification the die started, and defines the straight-line run-out: the first support point, the point at which the strand is self-supporting enough to be cut, and the point at which it is run off a table or coiled. The run-out length follows from the cycle and the alloy, because the distance a strand travels before it is solid is the average casting speed multiplied by the solidification time and the average speed is the stroke multiplied by the frequency, so a longer stroke shortens the run-out and a longer freezing range lengthens it. Setting and utility input: the alloy’s solidification time, the section and its wall thickness, the spray water and air supplies, and the run-out length available on site. Output: a zoned secondary-cooling setting with its length and ratio, a defined straight-line run-out with the first support point and the cut point marked, and the run-out length stated as a number the site has to find room for.

Steps 7 — Cycle Monitoring and Section Correction. The operator is watching three trends, and each names a different fault. The withdrawal force at an unchanged cycle is the die’s condition: a force that climbs says the shell is gripping more than it did, which means the die bore has changed, the cooling has moved or the pause is too short, while a force that falls with a rising die temperature says the opposite. The die and cooling-circuit temperatures at the start plane say whether the thermal path is still what it was set to be, and they are the earliest warning of the film boiling that precedes a breakout. The section and the as-cast surface say whether the product is on specification, and because the strand replicates the die the surface is a statement about the die as much as about the product. Corrections are made in a deliberate order — pause and stroke first, then cooling, then the die — because the cycle is the cheapest thing to change. Setting and utility input: the force and temperature instrumentation, the section and surface measurement arrangement, and the drawing tolerances. Output: a running record of withdrawal force, die and circuit temperatures, level, section and as-cast surface against the baseline, with each correction recorded against the measurement that prompted it.

Steps 8 — Synchronised Cutting and Cut-Length Control. A continuous line cannot stop to cut, so the cut travels with the strand: a saw or shear is synchronised to the withdrawal, closes on the section while it is moving, and returns while the next length is being cast. This stage sets the cut length, the synchronisation and the end condition. The cut is made in a defined position relative to the point at which the strand is self-supporting, because a cut made while the section is still soft deforms the end the drawing bench grips first. Whichever device is fitted, the synchronisation has to survive the cycle’s stops and starts rather than a steady speed. Setting and utility input: the required cut length and tolerance, the cut-end condition required downstream, the cutting device and its synchronisation arrangement, and the blade condition. Output: a cut length with its tolerance and end condition, a synchronisation setting that holds through the cycle’s stops and starts, and a blade condition recorded against a replacement trigger.

Steps 9 — Coiling or Stacking, Sampling and Line Reset. The last stage turns the cut length into a consignment and the line back into a starting condition. Straight lengths are run off a table and stacked or bundled; rod and tube are coiled where the downstream operation wants a coil, on a coiler whose tension matches a strand delivered in strokes rather than continuously. Sampling is taken here rather than asserted: the oxygen or gas sample where the target applies, the conductivity specimen where a conductivity figure is claimed, the section measurement and the as-cast surface record, each with the sampling point and the method named. The reset then closes the loop: the tonnes passed through this die are added to the die’s running total, the transition metal from any grade change is accounted for as product, internal return or scrap, and the die, break ring, rolls, blades and nozzles are inspected against their triggers. Setting and utility input: the sampling method, point and analysis arrangement, and the disposition route for transition metal. Output: a consignment with its length or coil weight and its identity, a measured sample set with the method and point named, and a reset record carrying tonnes per die and roll condition.

Product Structure (Main Equipment)

The machine is best read as five functional blocks in series — a metal supply that holds and presents the melt, a delivery path that decides where solidification starts, a die assembly that forms and cools the section, a withdrawal and cooling section that carries the strand until it can stand on its own, and a cutting and handling section that turns a continuous stream into a countable product — plus the instrumentation and the consumables register that make the behaviour of all five visible.

The melting and holding furnace

The melting furnace and the holding furnace are separate machines doing separate jobs, and the caster only works as well as the holder it is fed by. The melter receives the charge and brings it to temperature; the holder delivers the melt at a temperature and a level that do not move, because the metal head above the die axis is the pressure that feeds the shell as it contracts. Holding temperature is held in a narrow band by a power supply that is a control loop in its own right: published machine ranges state holding power and rated melting power separately, from about 30 kW to 160 kW of holding against about 60 kW to 720 kW of rated power. The holder’s geometry decides how the line behaves at a grade change, because the heel it can be emptied to is the heel that contaminates the next alloy. Where a furnace must be separated and tipped for cleaning between grades, the arrangement used is the one described under split tilting smelting furnace. The furnace block also includes the metal surface protection — a cover, a blanket or a shroud — and the level measurement.

The metal delivery path, the tundish and the break ring

Between the holder and the die sits the most consequential part of the machine. The metal leaves the holder through a launder or a spout, may pass through a tundish, and reaches the die through the joint at which the break ring is fitted. The break ring is the thermal break in this path: upstream of it the metal is a liquid at casting temperature, downstream of it the metal is a shell forming against a water-cooled die. A published specification names boron nitride for the ring and states that it fixes the start of billet crystallisation; a published patent describes rings whose skin is boron nitride, silicon nitride or a boron nitride and aluminium nitride composite on a zirconia, alumina or silicon carbide substrate. Nothing else in the machine can move the start plane, which is why the ring’s material, its thickness, its fit and its replacement trigger are specification items. The same block includes the joint’s sealing arrangement and the access that allows the ring and the nozzle to be inspected and changed without dismantling the die jacket.

The die, the mandrel and the water jacket

The die determines the shape, the surface and a large part of the running cost, and it is a grade of graphite rather than a material. Graphite is used in this class because it is not wet by the melt, because it conducts heat, because it resists thermal shock and because it is machinable into the fine geometry a hollow section needs; published die suppliers in this field list the alloy families cast through graphite — the copper and copper-nickel and nickel silver families, the brasses including the leaded grades, the tin, phosphor, manganese, silicon and aluminium bronzes, the aluminium-tin alloys, silver and gold and the coinage alloys, and grey and white cast irons. The bore or the slot is machined against the finished section with a shrinkage allowance and a finishing allowance deducted, and the die is held in a water-cooled jacket whose zoning, flow and seals are part of the thermal design. For hollow sections the mandrel forms the bore and its alignment and its own cooling are separate specification items; the wall of the product is the arithmetic difference between the die bore and the mandrel, so the two tolerances add. Published die lives in this field are quoted as hours — over 500 hours on one page, with a die change of fifteen minutes or, on another page, five — and the same sources publish coated graphite dies for the lead-free copper alloys.

Secondary cooling and the withdrawal unit

Secondary cooling is published as a spray zone with an adjustable water-to-air ratio over a defined length; a published specification for a 60 mm round gives a single zone 1,100 mm long, water regulated between 0.5 and 1.5 cubic metres per hour, air up to 50 normal cubic metres per hour and a ratio adjustable from 1:20 to 1:100. The withdrawal unit generates the cycle: a pair of clamping rolls or a pulling arrangement that grips the strand and releases it during the pause. A published specification in this class describes a two-roll withdrawal device with a spring clamp on the upper roller driven by a servomotor of about 30 kW, with a periodic withdrawal at 10 to 120 cycles per minute and a casting velocity up to 5 metres per minute. The unit’s design decisions are the clamping force and its uniformity, the roll material and its cooling, the alignment of the withdrawal axis with the die axis — a non-collinear axis imposes a bending moment on the shell where it is weakest — and the instrumentation, the withdrawal force being the primary indication of die condition. The support rolls along the run-out belong to the same block, because the strand’s straightness is produced by their alignment rather than corrected by a straightener.

Cutting, run-out and handling

The cutting block converts a continuous stream into countable lengths without stopping the line. A published specification in this class gives the cutting device as a hydraulic pendulum shear working at about 25 megapascals with a maximum cutting force of the order of a thousand kilonewtons on a 60 mm round, and it has to hold its synchronisation through the cycle’s stops and starts. The cut position is set relative to the point at which the strand is self-supporting, so the cut is not made in a soft section, and the end condition is specified for the operation that grips the end next. The run-out includes the table, the guides and, where rod or tube is coiled, a coiler whose tension has to accept a product arriving in strokes. The handling items that matter here protect the product rather than move it: guides that do not mark the as-cast surface, and arrangements that do not deform the bore of a hollow section.

Instrumentation, control and the consumables register

The machine’s behaviour is only as visible as its instrumentation, and on a horizontal line there are four measurements that carry most of the information. The withdrawal force or the drive’s torque over the cycle is the primary one. The die temperature and the cooling-circuit temperature at the start plane are the second. The metal level and its pressure at the die are the third. The section and the as-cast surface are the fourth. Around those, the control system carries the cycle as a set of stored recipes — a published listing in this field claims recipe storage for a hundred alloys — so that a change between grades restores a cycle rather than re-deriving one, and the alarms and interlocks cover loss of cooling flow, cooling temperature outside its band, metal level outside its band, drive overload or an abnormal force trend, metal temperature outside the holding band, and the cutting device’s synchronisation. The consumables register belongs in the same block as the instrumentation: the die in tonnes passed, the break ring by its replacement trigger, the withdrawal rolls, the shear blades or saw blades, the secondary-cooling nozzles, the jackets and seals, and the mandrel for a hollow section are the items whose replacement is triggered by a measurement.

Product Features

A withdrawal cycle that is programmable as stroke, stroke time, pause and reverse motion rather than as a single speed. The four parameters are stored per recipe, so a change of alloy or section restores a cycle instead of re-deriving one.
The cycle’s arithmetic is reported rather than concealed. The frequency, the average speed that follows from stroke times frequency, the duty fraction of the cycle and the instantaneous rate during the stroke are all shown, because the drive and the cooling are sized for the instantaneous event.
Drive force and torque instrumented over the cycle, not just at the motor terminals. The withdrawal force trend is the primary indication of die condition: a rising force at an unchanged cycle is the earliest sign of a changed bore or of moved cooling.
A die specification that names a grade with property values. Grain size, density, gas permeability, ash content and thermal conductivity are stated for the grade, with the consumable life in tonnes of metal passed and metres of strand.
Break ring specified by material and by replacement trigger. The ring fixes the plane at which solidification begins, so its material is selected against the alloy’s wetting and attack behaviour, and its replacement is triggered by a measurement.
A mandatory, replaceable mandrel for hollow sections, with its own alignment and cooling. Bore geometry is a specification for tube and hollow bar, and the wall is the arithmetic sum of the die bore and the mandrel tolerances.
Zoned die cooling specified by inlet temperature and permitted temperature rise. The heat to be removed is an arithmetic quantity — roughly 220 kilojoules per kilogram of latent and superheat for copper at a 30 K superheat, about 5.3 kilograms of water per kilogram of metal at a 10 K rise.
Zoned secondary cooling with an adjustable water-to-air ratio. One or more spray zones, each with its own ratio range and length, so that the heat the die did not take out is removed at a controlled rate.
A straight-line run-out whose length is computed from the cycle and the alloy and stated as a number. The layout marks the first support point, the cut point and the handling point, so the site knows what plan length the machine needs.
Collinear die and withdrawal axes, with the alignment datum recorded. A non-collinear withdrawal axis imposes a bending moment on the shell at its weakest point, so the alignment is set and recorded.
Melt surface protection and a protected transfer path where the duty needs them. A cover, a blanket or a shroud at the holder and at the die mouth, and a below-surface or short-path transfer, specified against the alloy and the oxygen target.
Synchronous cutting with the synchronisation rated for an intermittent strand. A saw or shear that holds its position through the cycle’s stops and starts, with the cut made in a section that is no longer soft.
Recipe storage per alloy and per section. A stored parameter set for the cycle, the cooling zones, the level band and the cut length, so the line’s starting condition for a grade is a recalled record rather than a derived guess.
Alarms and interlocks on the four measurements that matter. Cooling flow and temperature outside band, metal level outside band, drive overload or an abnormal force trend, holding temperature outside band, and loss of cutting synchronisation — each tripping or alarming as its risk requires.
Surface condition treated as a die record rather than as an appearance item. Because the strand replicates the die bore or slot, the as-cast surface is a measurement of the die: a scored, eroded or heat-checked bore shows in the surface record before it shows in the dimensional one, so the surface is recorded per campaign.
A consumables register kept in tonnes, cycles and measurements. Die, break ring, withdrawal rolls, shear or saw blades, secondary-cooling nozzles, jackets, seals and mandrel listed against the measurement that triggers replacement, with the die in tonnes passed.
A baseline record that makes drift visible from the first campaign. Cycle, cooling, level, section, surface and withdrawal force recorded at the design point, so the first sign of die wear appears as a movement away from a number.

Technical Parameters And Specifications

The tables below separate three kinds of number, and keeping them apart is the whole of a fair comparison between two quotations. Site values — the alloy and its analysis, the section and its tolerance, the annual tonnage, the available floor length, the cooling water temperature and the electrical supply — are given as inputs. Machine values — die bore, mandrel, stroke, pause, cooling zoning, run-out length, cut length — are given as outputs. Published values — the duty-cycle figures, materials, cooling arrangements, alloy families and standard grades — are given with their published basis.

Table 1 — Machine and line specification

Parameter	Specification
Equipment type	Horizontal continuous casting line: furnace, tundish and break ring, water-cooled die, secondary cooling, withdrawal unit, straight-line run-out, instrumentation and a consumables register
Product families	Round bar, hollow bar and tube, flat strip and busbar, and shaped sections to a die profile; feedstock for drawing, extruding or machining
Alloy families	Copper and its oxygen-free and deoxidised grades, brasses including leaded and lead-free, tin, phosphor, manganese, silicon and aluminium bronzes, cupro-nickels, nickel silvers, zinc and zinc alloys, aluminium alloys, cast and white cast irons, and the silver, gold, coinage and resistance alloys
Duty defined by	Alloy analysis; section, tolerance and finishing allowance; annual and hourly tonnage; superheat; oxygen or gas target; floor length; cooling water temperature and quality; electrical supply
Withdrawal method	Periodic withdrawal, with a pause between strokes and a short reverse motion in the pushback variant
Withdrawal cycle parameters	Stroke length, stroke time, pause time, reverse-motion length, frequency; see Table 2
Casting speed	The cycle’s average, stroke times frequency; the instantaneous rate beside it
Drive	Servo or equivalent controlled withdrawal drive, force or torque over the cycle instrumented; a published specification describes a spring-clamped two-roll device with a servomotor of about 30 kW
Die	Graphite, as a grade with grain size, density, gas permeability, ash content and thermal conductivity stated; the bore machined with the shrinkage and finishing allowances deducted
Mandrel	Fitted for hollow sections, with its own alignment, cooling and replacement trigger; the wall is die bore less mandrel
Break ring	Refractory ring between melt and die, fixing the plane at which solidification begins; published materials include boron nitride, silicon nitride and a boron nitride and aluminium nitride composite on a zirconia, alumina or silicon carbide substrate
Published die and break ring numbers	A published die life of over 500 hours and a die changeover of 15 minutes, with a 5-minute figure on another page; published graphite dies rated to about 1,650 °C
Mould cooling	Zoned die jacket cooling, by inlet temperature, permitted temperature rise and flow
Heat to be removed	For copper, roughly 220 kJ per kilogram of latent heat and superheat at a 30 K superheat; about 5.3 kg of water per kilogram of metal at a 10 K rise and about 2.6 at a 20 K rise
Secondary cooling	One or more spray zones with an adjustable water-to-air ratio; a published specification gives a single zone 1,100 mm long, water regulated between 0.5 and 1.5 m3/h, air up to 50 nm3/h and a ratio adjustable from 1:20 to 1:100
Run-out	Straight-line run-out with the first support point, cut point and handling point marked; its length is the average speed times the solidification time
Cutting	Synchronous saw or shear sized for an intermittent strand; a published specification gives a hydraulic pendulum shear at about 25 MPa with a maximum cutting force of the order of 1,000 kN on a 60 mm round
Cut length and end condition	Length and tolerance, and an end condition specified for the next operation to grip it
Melt surface protection	Cover, blanket or shroud at the holder and the die mouth, against the alloy and the oxygen target
Instrumentation	Withdrawal force or drive torque over the cycle, die and circuit temperature at the start plane, metal level and pressure at the die, section and surface, cutting synchronisation
Control	Stored recipes per alloy and section for the cycle, cooling zones, level band and cut length
Interlocks	Loss of cooling flow, cooling temperature outside band, metal level outside band, holding temperature outside band, drive overload or abnormal force trend, loss of synchronisation
Consumables	Die, break ring, mandrel, withdrawal rolls, shear or saw blades, nozzles, jackets, seals and gaskets, listed against the measurement that triggers replacement
Capacity	Engineered per project against the measured alloy analysis, the section and its tolerance, the annual and hourly tonnage, the alloy sequence and the floor length; no fixed tonnage, bore, stroke or floor length is quoted
Utilities	Electrical supply for melting and holding power and the drives; cooling water with a stated temperature and quality; spray water and compressed air for secondary cooling; extraction for the off-gas
Footprint	Engineered against the run-out length and the access the die and the break ring require; a published specification gives one 60 mm machine a technological length of 6.0 m, an overall length of 22.0 m and a height to the tundish top of 1,750 mm
Design code	None published for the machine in this class; the governing instruments are the owner’s specification and a measured cast record

Table 2 — The withdrawal cycle: what each parameter does and the published reference values

Parameter	What it does	Published reference values in this class	Consequence of moving it
Stroke length	One pull’s advance; times frequency, the average speed	40 to 80 mm on a 60 mm round billet	A longer stroke raises the average speed and shortens the run-out
Stroke time	The pull’s duration; the instantaneous rate	0.2 to 0.25 s	A shorter stroke time raises the instantaneous rate
Pause time	The dwell between pulls, in which the shell thickens	0.6 to 0.75 s	A longer pause is safer; too short a pause tears the shell
Reverse motion	The short pushback, which relieves the friction	Feature of the periodic pull-pushback-pause method	It allows a section that would otherwise seize
Frequency	Cycles per unit time, from the three durations	10 to 120 per minute as a machine range; 60 to 75 per minute for the grade actually cast	Frequency and stroke trade at a fixed average speed
Average casting speed	The speed on a quotation; stroke times frequency	Up to 5 m/min as a machine rating; 4.0 to 5.0 m/min for the grade actually cast	A speed quoted without the cycle cannot be compared
Duty fraction	The share of the cycle in which the strand moves	About 0.25 on the published figures above, computed as 0.2 s divided by 0.8 s and 0.25 s divided by 1.0 s	A quarter duty is what the cooling and the drive see
Instantaneous rate during the stroke	The rate at which metal moves	About 12 to 19 m/min on the published figures above, computed from 40 mm in 0.2 s and 80 mm in 0.25 s	About four times the average; the design is sized against it
Cycle stability point	The combination stable in service	4.0 m/min at a cycle time of 1.0 s in the published trial record	Found by raising the stroke while watching the force trend

Table 3 — Die, break ring and consumables: function, failure mode and the unit of life

Item	Function	What ends its life	Unit in which its life belongs
Graphite die	Forms the section and removes most of the heat	Bore abrasion and thermal cycling, until the section leaves tolerance	Tonnes of metal passed, or metres of strand, not hours
Die grade properties	Set the thermal path and the interface friction	A grade that will not hold a gas film, or whose ash is wrong, fails immediately	Property values at order, not a service interval
Break ring	Fixes the start plane and provides the thermal break	Thermal shock, erosion and reaction, with the start plane moving as it wears	Replacement trigger measured at the die
Mandrel	Forms the bore of a hollow section	Wear and thermal distortion, which change the bore and the wall	Tonnes passed, and alignment against the die
Withdrawal rolls and clamps	Grip the strand, transmit the stroke, release during the pause	Abrasion and heat, with the clamping force falling away	Withdrawal force trend at an unchanged cycle
Shear blades or saw blades	Cut the strand synchronously	Thermal fatigue and edge wear, the cut end leaving condition first	Cut-end condition, measured per cut
Secondary-cooling nozzles	Remove the heat the die did not	Blockage and scale, changing the water-to-air ratio	Spray pattern and ratio measurement
Jackets, seals and gaskets	Contain the cooling water and hold the zoning	Ageing and thermal cycling, leaks first at the highest-flux zone	Leak test at the start plane zone
Melt surface protection	Keeps the oxygen target achievable at the die mouth	Consumption and degradation, showing as an oxygen or surface result	Sampling result against the target

Table 4 — Profile families and the machine element that sets each dimension

Profile family	What sets the outside dimension	What sets the inside dimension	What the wall or thickness is	Where the tolerance comes from
Round rod and bar	Die bore, with shrinkage and finishing allowance	Not applicable	Not applicable	Die bore tolerance, less the allowances
Hollow bar and tube	Die bore	Mandrel	Bore less mandrel	The sum of two independently tolerated dimensions
Flat strip and busbar	Die slot width	Not applicable	Die slot opening	Slot machining tolerance for width and thickness, less the finishing allowance
Shaped section to a die profile	The die profile	The mandrel where hollow	Varies around the profile	The die is the drawing; the profile must be defined before it is cut
Straightness	Not a die dimension	Not applicable	Not applicable	Run-out alignment and the cut, with no straightener in the line
Surface finish	The strand replicates the die bore or slot, transferring the die’s surface	Not applicable	Not applicable	A scored, eroded or heat-checked bore shows in the surface record first

Table 5 — Cooling and utilities: what has to be stated and why the flow alone is not enough

Quantity	Why it is a specification item	The arithmetic that links it	What a figure without it fails to establish
Cooling water inlet temperature	The margin between the die wall and the boiling point	With a permitted rise it fixes the flow	A flow without an inlet temperature says nothing
Permitted temperature rise across the die jacket	Film boiling replaces nucleate boiling and collapses the coefficient	Roughly 220 kJ per kilogram of latent and superheat for copper is about 5.3 kg of water per kilogram of metal at a 10 K rise and about 2.6 at a 20 K rise	A rise chosen for economy rather than the wall limit precedes a breakout
Zoning of the die jacket	The start-plane flux is several times the average	Each zone has its own flow and temperature measurement	A bulk outlet figure averaging a hot zone with a cold one
Secondary-cooling water and air rates	The heat the die did not remove is removed here	A published arrangement regulates water between 0.5 and 1.5 m3/h and air up to 50 nm3/h, ratio adjustable from 1:20 to 1:100	A cooling length without a ratio, or a ratio without a length
Cooling water quality	Scale and corrosion change the coefficient at the wall	The limit is the jacket’s narrowest passage and the highest-flux zone	A scaled passage does not pass the designed flow
Compressed air supply	Required for water-to-air secondary cooling and a pneumatic cutting device	The ratio range and zone length set the air demand	A ratio quoting a supply pressure the site lacks
Electrical supply and the holding load	The metal is held hot far longer than it is cast	Published machine ranges state holding power separately from rated melting power, from about 30 kW to 160 kW against about 60 kW to 720 kW	An installed load quoted as one figure, holding cost left out
Extraction and the off-gas path	Surface protection, coatings and moisture must leave	The duty is set by the alloy, the charge and the protection method	A caster installed with no allowance for them
Drainage, dross and transition metal	Dross, transition metal and off-spec lengths need a route	The transition quantity follows from the alloy sequence and the heel the holder can be emptied to	An operating cost arriving as an unplanned disposal

Table 6 — Alloy families, what they do to the die and what the atmosphere has to be

Family	What it does to the die and the break ring	What the metal surface needs	What changes in the cycle
Oxygen-free and deoxidised copper	Benign to graphite; the duty is dominated by the metal’s high thermal conductivity	Oxidation protection at the holder, the transfer and the die mouth	A fast shell allows shorter pauses; the risk moves to the surface
Free-cutting brass, leaded	Cast through graphite as published course; the duty is moderate	Ordinary practice; the lead is in the melt	Predictable, and the reference for any substitution
Free-cutting brass, lead-free	Published as very aggressive to graphite, with coated dies offered	Ordinary practice, but the die qualification has to be redone	The die grade and life have to be re-established in tonnes
Tin, phosphor, manganese, silicon and gunmetal bronzes	Oxide-forming and a wide freezing range	A short or protected transfer path	A longer pause, and a longer run-out
Aluminium bronze and aluminium-tin alloys	Tenacious oxide and a higher hot strength, so the shell is stiffer	The most demanding transfer protection in the copper family	The cycle is set for the alloy, not borrowed from copper
Cupro-nickel and nickel silver	Lower thermal conductivity, so the shell gains strength more slowly	Protection where the oxygen or hydrogen result matters	A longer pause than pure copper
Zinc and zinc alloys	A much lower casting temperature, so a smaller gradient at ring and die	Ordinary practice at the lower temperature	The heat load and zoning change, and with them the cycle
Aluminium and aluminium alloys	Affinity for oxygen and a different oxide film	A shroud or blanket as a specification item	The metal surface, not the shell strength, governs rejects
Cast iron and white cast iron	A casting temperature far above the copper family’s	Ordinary practice at the higher temperature, extraction sized for it	A slower cycle, a thicker shell at the pull, a different die and ring
Silver, gold, coinage and resistance alloys	Cast through graphite in the same machine family	Protection where a high-value surface requires it	The cycle is secondary to the grade sequence; the heel is the contaminant

Table 7 — Acceptance measurements and what each one catches

Measurement	How it is taken	What it catches
Melt analysis before the cast	A sample from the actual bath, not the purchase order	A composition that would have produced an unsellable section
Superheat	Bath temperature against the liquidus of the actual analysis	A bath too cold to reach the die, or too hot for its cooling
Oxygen or gas content where a target applies	A sample at a named point by a named method	A section dimensionally correct and analytically out of specification
Cycle record	Stroke, stroke time, pause, reverse motion, frequency and the average speed from them, per campaign	A quotation whose speed cannot be reproduced
Withdrawal force or drive torque trend	Recorded over the cycle at each start-up step and through the campaign	Die wear, a bore change, a cooling change, too short a pause
Die and circuit temperature	At the start-plane zone of the die and the circuit return	The heat-transfer change that precedes a breakout
Metal level and its stability	A band over the campaign, not a set point	The pressure variation that varies the section
Section and surface	Against the drawing with the finishing allowance deducted, the as-cast surface per campaign against its die	An out-of-tolerance section, and a die that moved before the dimension did
Straightness	Over the cut length against the run-out alignment datum	A run-out misalignment with no straightener to correct it
Conductivity or resistivity where claimed	A specimen with its measurement temperature and condition stated	A conductivity figure not comparable with any other
Cut length and end condition	Per cut, against the specification of the operation that grips it	The first defect the drawing bench or extruder would meet
Transition and off-specification metal	Weighed and analysed, with its disposition as product, internal return or scrap	An unexplained metal loss, usually a blending problem
Consumable life record	Tonnes passed per die, ring replacement trigger, roll and blade condition, nozzle spray	A running cost otherwise invisible until the accounts
Baseline file	The design-point cycle, cooling, level, section, surface and force carried forward	Drift, invisible without a recorded starting number

Technical Advantages

The cycle is designed from the alloy’s solidification behaviour instead of copied from a similar machine. The pause length that lets the shell survive the next pull is a function of the alloy’s freezing range, the section’s wall thickness and the die’s cooling path, and it is therefore computed for the duty.
The design is checked against the arithmetic that the quotation publishes. Stroke multiplied by frequency is the average speed, stroke divided by stroke time is the instantaneous rate, and stroke time as a fraction of the cycle is the duty. A published specification in this class states 40 to 80 mm, 60 to 75 per minute, 0.2 to 0.25 s and 0.6 to 0.75 s against a velocity of 4.0 to 5.0 m/min.
The start plane of solidification is treated as a designed quantity rather than an outcome. The break ring fixes it and nothing else can move it, so the ring’s material is chosen against the alloy’s wetting and attack behaviour and its replacement is triggered by a measurement.
The die is bought on properties, not on the word graphite. Published suppliers in this field sell graphite moulds by grade, and published practice includes coated dies for the lead-free copper alloys, which are described as aggressive to graphite. The values that matter are grain size, density, gas permeability, ash content and thermal conductivity.
Die life is quoted in the unit in which a die actually wears. Published figures in this field are given in hours — over 500 on one page — and tonnes of metal passed and metres of strand per die are reproducible across sites, so they are the figures on which a running cost can be built.
Cooling is specified against the wall temperature limit rather than against a flow. Stating the inlet temperature, the permitted rise and the zoning — with about 5.3 kg of water per kilogram of copper at a 10 K rise as the arithmetic behind it — is what makes the cooling a specification instead of a utility connection.
The run-out length is computed and then reconciled with the site. Because the run-out length is the average casting speed multiplied by the solidification time, and the average speed is the stroke multiplied by the frequency, the plan length of a horizontal line is a consequence of the cycle and the alloy.
The straight-line advantage is collected deliberately rather than claimed generically. The reason to buy a horizontal machine is that the strand is never bent while it is soft, which is what makes crack-sensitive and short-freezing-range alloys and hollow sections practical and what removes the pit and the tower from the civil works.
Tolerances are attributed to the elements that produce them. Diameter to the die bore, bore to the mandrel, width and thickness to the die slot, straightness to the run-out alignment, and the surface to the die whose bore formed it. As-cast wall is the sum of two tolerances.
The oxygen and conductivity results are offered as measured quantities with named methods. The oxygen-free grades are defined by an upper limit of 0.001 per cent for Cu-OF and 0.0005 per cent for the electronic grade, published values on the vertical routes in this field sit at 1 to 3 ppm, and 100 per cent IACS is a resistivity of 0.017241 Ω·mm2/m.
The machine’s wear is instrumented so that it can be seen before it becomes a rejection. The withdrawal force over the cycle, the die and circuit temperatures, the level band, the section and the as-cast surface show die wear, a cooling change and a level problem as different signatures.
The consumables are quoted as a running cost expressed in the units in which they are consumed. Die in tonnes, break ring by trigger, rolls and blades by condition, and nozzles by spray pattern.
The interface to the melt shop, the environmental line and the downstream operation is written down. What the melt surface, the charge’s coatings and its moisture produce has to leave the building, and where that off-gas is acidic the extraction is closed out in a wet scrubbing line of the kind described under flue gas absorption tower and, where a nitrogen oxide fraction is present, under NOx treatment equipment.
The duties that the machine should not take are refused rather than quoted. A finished-product tolerance with no downstream operation; an unmeasured alloy; a grade substitution with no die qualification; a tonnage whose run-out length makes the plan impossible; a site with no route for dross or transition metal; and a requirement for discrete ingots, granules or powder, each of which belongs to a different machine.

Service Process

1. Enquiry and duty definition. The process starts with the section, not with the machine: what the product is for, which operation will consume it, what tolerance that operation needs at its input, what annual and hourly tonnage is required, which alloys and in what sequence, and what floor length and cooling water the site has.

2. Melt and metallurgical review. The alloy’s freezing range, its thermal conductivity, its oxide-forming tendency and its behaviour against graphite and against the proposed break ring material are reviewed against the section, and the superheat window, the likely cycle and the solidification time that fixes the run-out are established.

3. Cycle and cooling design. The stroke, the stroke time and the pause are proposed for the alloy and the section, with the duty fraction and the instantaneous rate; the die cooling is set from the heat balance and from the permitted temperature rise at the wall; and the secondary cooling zoning, the run-out length and the cut position are derived from the same numbers.

4. Die and tooling engineering. The die bore or slot is cut against the finished section with the shrinkage and the finishing allowance deducted; the mandrel is cut and its alignment defined for a hollow section; the break ring material is selected and its fit specified; and the die grade is stated with its property values and its expected life in tonnes.

5. Manufacturing and inspection. The furnace, the delivery path, the die assembly and jacket, the withdrawal unit, the run-out, the cutting device and the control system are manufactured and inspected against the drawings, with the die’s bore and the jacket’s zoning measured and recorded rather than accepted on the supplier’s certificate.

6. Factory acceptance test. The line is assembled and run, and the acceptance test covers the mechanical items — the cycle’s parameter set and the actual motion it produces, the withdrawal force profile, the cooling flows and temperatures zone by zone, the level control’s behaviour, the cutting synchronisation, and the interlocks — together with the casting of a first section whose dimensions, surfaces and, where applicable, analytical results are measured.

7. Site preparation and installation support. The layout is confirmed against the actual floor — machine length, run-out length, furnace and handling area, cooling equipment and the access the die and the break ring need for a change — and the foundation, the utilities and the extraction connections are checked against the design before the line is moved in.

8. Commissioning and cycle development. Commissioning is a development process rather than a start-up: the cycle is brought up at a reduced stroke with the withdrawal force watched at each step, the pause is set for the alloy, the cooling zoning is trimmed against the die and circuit temperatures, and the run-out and cut positions are confirmed.

9. Sampling, measurement and baseline. The section and the as-cast surface are measured, the cut length and end condition are checked, and where an oxygen, gas or conductivity figure is claimed it is established by the agreed method at the agreed point.

10. Operator and maintenance training. Training covers the cycle’s four parameters and the arithmetic between them, what each of the three trends means and the order in which corrections are made — cycle first, cooling second, die last — the die, mandrel and break ring change, the consumables register, the sampling procedure, and the circumstances in which the line must be stopped rather than adjusted.

11. Production support through the first campaign. Support through the first full campaign covers the first grade change, the first die change, the interpretation of the first force and temperature trends, and the disposition of the transition metal.

12. Documentation. The delivery includes the cycle parameter records, the die, mandrel and break ring drawings, the cooling zoning and heat balance, the run-out and cut-position layout, the instrument list, the consumables register, the acceptance test record and the baseline file.

Warranty And After-Sales Service

What the warranty covers

The warranty covers the machine as manufactured: the melting and holding furnace and its power supply, the metal delivery path with the tundish and the break ring seating, the die assembly and jacket, the mandrel where fitted, the withdrawal unit and its drive, the secondary-cooling arrangement, the run-out and its supports, the cutting device and its synchronisation, and the control system and instrumentation, against defects in materials and workmanship under the operating conditions and the cycle recorded at handover. It also covers the line’s measured performance at the design point — the section and its tolerance, the cut length and its end condition — for the alloy, the section and the cycle written into the acceptance record.

What is excluded

The warranty does not cover the consumables: the graphite die, the break ring, the mandrel, the withdrawal rolls and their clamps, the shear or saw blades, the secondary-cooling nozzles, jackets, seals and gaskets, and the melt surface protection items are all wear items, supplied and priced as such. It does not cover a section that is out of tolerance because the cycle was changed away from the recorded setting, because the die was replaced with one not made to the drawing, or because the alloy was changed without re-establishing the cycle and the cooling; a rejection traceable to an unmeasured or off-analysis melt; damage from a charge containing moisture, organics or unsorted material; corrosion or blockage from cooling water outside the agreed quality; and any consequence of operating the line with an interlock bypassed.

Spare parts and consumables

The recommended spare set covers the items whose failure stops the line rather than the items that are expensive: a complete die and mandrel set for the main section, break rings, a set of withdrawal rolls or clamps, a set of shear or saw blades, a set of secondary-cooling nozzles, jacket seals and gaskets, the instrument spares for the four measured quantities, and the control system’s parameter backup. Consumable items are quoted with their expected life in tonnes passed for the actual duty, and the register that comes with the machine is designed to be updated from the plant’s own records.

Remote support and diagnostics

Remote support is built on the data the machine already records. The cycle parameters, the withdrawal force over the cycle, the die and circuit temperatures, the metal level band, the holding temperature and the cutting synchronisation are archived, so a fault can be discussed against a trend. The usual requests that begin here are a force trend that has climbed without a change in the cycle, a section that has moved while the force has not, a die temperature that rises at start-up, a level that will not hold its band, and a cut length that drifts.

Field service and cycle development

Field service covers installation supervision, commissioning, cycle development on the actual alloy, die and break ring changes during the first campaigns, and any condition that the remote review cannot close out. Cycle development is a service in its own right: the stable point of a new alloy or a new section is found by raising the stroke in steps while watching the force, and the figures that come out of it — the pause that holds the section, the cooling rise that holds the die wall, the run-out length that the solidification time requires — become the plant’s own operating standard.

Operating and maintenance support

Operating support covers the sequence of a grade change, the order in which corrections are made when the section drifts, the sampling procedure where an oxygen, gas or conductivity figure is claimed, and the disposition of transition and off-specification metal. Maintenance support covers the die and break ring change with its alignment and preheat, the jacket and seal inspection, the withdrawal roll and clamp condition, the cutting device’s blade and synchronisation setting, the secondary-cooling nozzle and spray pattern check, and the cooling circuit’s quality limits.

Performance review and re-rating

The line is reviewed periodically against the baseline file, and the review has three outcomes. Where the measured consumable life differs from the life quoted at purchase, the register is updated to the measured figure. Where the duty has changed — a new alloy, a heavier section, a tighter tolerance, a different downstream operation — the cycle, the cooling, the die and the run-out length are re-derived. Where the required tonnage has grown, the re-rating is assessed honestly: a horizontal line’s answer to more tonnage is more strands, a longer line or a second machine, and beyond a certain point the correct answer is a different process.

Contact and documentation

The delivery documentation set is the reference for every support conversation: the cycle parameter records, the die, mandrel and break ring drawings, the cooling zoning and its heat balance, the run-out and cut-position layout, the instrument list, the consumables register, the acceptance test record and the baseline file. Support is arranged through the contact channel named in the contract, with the machine’s serial number and the relevant record attached.

Frequently Asked Questions

What is a horizontal continuous casting machine?

A horizontal continuous casting machine feeds molten metal into a water-cooled die lying on its side, withdraws the solidifying strand along the same axis in short strokes, and cuts it to length without stopping the line. Its output is a semi-finished long product, a round rod or bar, a hollow bar or tube, a strip or a shaped section, which goes on to a drawing bench, an extruder, a rolling mill or a machining line. The horizontal layout means the strand is never bent while soft, the machine occupies floor rather than height, and the withdrawal force is produced against the friction of the shell in the die rather than by the strand’s weight.

Why is the withdrawal intermittent rather than continuous?

Because a horizontal strand has no gravity assisting it out of the die, the whole withdrawal force is the friction of the contracting shell against the die bore, and a steady pull would either tear a shell that is still thin at the entry or seize. The pause lets the shell thicken before it is pulled again and lets the interface at the die relax, and in the pushback variant a short reverse motion relieves the friction instead of adding to it. A published specification in this class states a periodic pull-pushback-pause method with a stroke of 40 to 80 mm, a stroke time of 0.2 to 0.25 seconds and a pause of 0.6 to 0.75 seconds.

What is the casting speed of a horizontal continuous casting machine?

It is not a single number, because it is the stroke multiplied by the frequency of the cycle. A published specification in this class gives a stroke of 40 to 80 mm and a frequency of 60 to 75 cycles per minute against a casting velocity of 4.0 to 5.0 metres per minute for the grade actually cast. That is why the stroke, the stroke time and the pause are the figures to ask for rather than a speed alone.

What is the pull length and how is it chosen?

The pull length, usually called the stroke, is the distance the strand advances in one pull, and it is chosen as a compromise between output and shell strength rather than from a table. Published practice in this class runs a 60 mm round billet at 40 to 80 mm of stroke, with a stable point of 4.0 metres per minute at a cycle time of one second.

Why does the strand get pushed back before the next pull?

The reverse motion, usually called pushback, relieves the friction between the shell and the die instead of adding to it, and it is what makes sections and alloys castable that would seize under a plain pull-pause cycle. During the pull the shell is pressed against the die bore by contraction and by the metal head behind it, and the pushback lets that contact relax and lets the gas or liquid film at the interface re-form before the next stroke. A published specification in this class describes the withdrawal method as periodic with the pull, pushback and pause sequence.

What is a break ring and why does it matter?

The break ring is the refractory ring between the metal supply and the die, and its downstream face is the plane at which solidification begins, so nothing else in the machine can move the start of the shell. A published specification in this class names boron nitride for the ring and states that it fixes the start of billet crystallisation. Because it wears, its material must be chosen against the alloy’s wetting and attack behaviour and its replacement triggered by a measurement, or the section moves as the ring does.

What is the mould length in a horizontal continuous casting machine?

Mould length is one of the least published numbers in this field: no machine page for a non-ferrous horizontal caster read in this survey states it, while a published specification for a steel billet machine in the same class gives an 800 mm tube mould with a cooling water flow of 45 cubic metres per hour. The length is set by the same balance as the cycle: the die has to be long enough for the shell to gain the strength the next stroke needs and short enough that the friction of the whole length does not exceed what the drive can pull or the shell can survive.

Which graphite grade should the die be made from?

The grade is a function of the alloy and the section rather than of the word graphite, and it should be bought on property values. The properties that matter are the ones that set the thermal path across the die wall and the friction at the interface between shell and bore: grain size, density, gas permeability, ash content and thermal conductivity. Published practice in this field includes coated dies offered specifically for the lead-free copper alloys, which are described as very aggressive to graphite.

How long does a graphite die last?

A published figure in this field is a claim of over 500 hours, but hours are the wrong unit, because the die wears by thermal cycling and abrasion per unit of metal passed rather than per hour of the calendar. The reproducible units are tonnes of metal passed and metres of strand per die, and those are the figures that make a running cost calculable.

Can a horizontal machine cast tube and hollow sections?

Yes. A hollow section is formed by a mandrel inside the die bore, so the outside diameter comes from the die and the inside diameter from the mandrel, and the strand can be withdrawn straight because there is no bending radius in the machine to force the tube over. Published supplier ranges for this duty quote tube outside diameters from 10 mm to 250 mm with walls from 0.5 mm to 15 mm, and published plant specifications in the same class give tube outside diameters from 16 mm to 400 mm with bores from 8 mm to 360 mm at casting speeds between 30 and 500 mm per minute.

What sets the diameter and the wall tolerance of the cast section?

The outside dimension comes from the die bore or the die slot, the bore of a hollow section comes from the mandrel, and the wall is the arithmetic difference between those two, so a wall tolerance is the sum of two independently tolerated dimensions and cannot be quoted as a figure in its own right. Thickness and width of a strip both come from the die slot, and straightness is not a die dimension at all: in a straight-line machine it comes from the run-out support alignment and the cut.

Can a horizontal machine cast oxygen-free copper?

Yes, but the oxygen figure is a property of the whole melt path rather than of the machine, so it has to be engineered and then measured instead of asserted. The oxygen-free grades are defined by an upper limit rather than by a process, 0.001 per cent for Cu-OF and 0.0005 per cent for the oxygen-free electronic grade, and published values for the vertical routes in this field sit at 1 to 3 ppm and below 3 ppm while one published horizontal copper rod line states a limit within 10 ppm.

What oxygen content can be guaranteed and how is it verified?

The grades are defined by an upper limit, 0.001 per cent or 10 ppm for Cu-OF and 0.0005 per cent or 5 ppm for the oxygen-free electronic grade, and published figures for the vertical routes in this field sit at 1 to 3 ppm and below 3 ppm. What can be guaranteed on a particular line is established by measurement rather than by design intent, so the guarantee should name three things: the sampling point; the sampling method; and the analysis technique, together with its detection limit.

How much cooling water does the line need?

It is set by the heat that has to leave the metal and by the temperature rise you are willing to permit, not by the size of the machine. Removing the latent heat and the superheat from copper is roughly 220 kilojoules per kilogram at a 30 K superheat, so the die circuit needs about 5.3 kilograms of water per kilogram of metal at a 10 K rise and about 2.6 at a 20 K rise, with the secondary cooling taking the balance that the die did not. Published practice in this class gives one 60 mm machine a mould cooling flow of 45 cubic metres per hour and a secondary-cooling zone regulating water between 0.5 and 1.5 cubic metres per hour with air up to 50 normal cubic metres per hour.

What is the metallurgical length and why does it set the floor length?

The metallurgical length is the distance the strand has to travel before it is solid enough to be supported, cut or handled, and in a horizontal line that distance is bought as floor length. It equals the average casting speed multiplied by the solidification time, and because the average casting speed is the stroke multiplied by the frequency, the run-out length is a consequence of the cycle and the alloy rather than a layout preference: a longer stroke shortens it and an alloy with a longer freezing range lengthens it.

Horizontal or vertical continuous casting, which should be bought?

Horizontal wins where the strand should not be bent while it is soft, which makes crack-sensitive and short-freezing-range alloys and hollow sections practical; where the building is low, the pit is expensive or the civil works dominate the budget; and where the plant runs several alloys and sections in modest tonnages and needs to change over repeatedly. A vertical, curved or upward route wins where a single alloy is produced at high tonnage, where the section is large enough that the horizontal run-out becomes an unreasonable plan length, where floor space is dearer than height, and where the product is a rod whose published oxygen figures sit on those routes.

Which alloys can be cast horizontally?

Published practice in this field casts the copper family, including the oxygen-free and deoxidised grades, the brasses with their leaded and lead-free variants, the tin, phosphor, manganese, silicon and aluminium bronzes, gunmetal, the cupro-nickels and the nickel silvers, together with zinc and zinc alloys, aluminium alloys, and in the same family of graphite-mould machine grey and white cast irons, silver, gold and the coinage alloys. What matters is not the list but the consequence of each family: the lead-free brasses are published as aggressive to graphite and need a qualified or coated die, the aluminium bronzes form a tenacious oxide, the cupro-nickels conduct heat less well than copper and need a longer pause for the same section.

How long does an alloy changeover take?

Longer than the die change figures suggest, because they are different numbers. Published die changeovers in this field are about fifteen minutes on one page and five minutes on another. An alloy change is a sequence: the residual heel in the holding furnace, the launder and the tundish has to be displaced or run out, the die, the mandrel and the break ring may all change, the die’s thermal steady state has to be re-established, and the first lengths are transition metal until the section and the metallurgical condition are on specification.

What wears out first on the machine?

The die wears first, and the withdrawal force trend at an unchanged cycle is how you see it, because a force that climbs means the shell is gripping more than it did. After the die the order is the break ring, whose wear moves the plane at which solidification begins; the withdrawal rolls and clamps, whose condition also shows in the force and in marks on the surface; the shear or saw blades, whose wear appears in the cut-end condition before it appears in the length; and the secondary-cooling nozzles, whose blockage changes the water-to-air ratio and therefore the cooling along the run-out.

When is a horizontal continuous casting machine the wrong answer?

When the requirement is a finished product with no downstream operation behind it, because this machine makes semi-finished feedstock. When the requirement is a discrete cast piece of defined weight rather than a continuous length, or a granulated or powdered form, each of which belongs to a different machine. When the alloy has no measured composition and no stated property or gas target, because the caster fixes the composition it is given. When the annual tonnage is high enough that the run-out length this layout needs makes the plan unaffordable, where a vertical or curved route is the honest answer. When a leaded grade is being replaced by a lead-free one with no die qualification behind the substitution. And when the site has no route for the dross, the transition metal or the off-gas.