Atomization Powder Making Equipment
— atomization powder making equipment
An atomization powder-making system is specialized industrial equipment used to convert bulk metals and alloys into fine, ultra-clean, spherical metal powders. It is most commonly configured as a VIGA system — vacuum induction melting inert gas atomization — or an EIGA system — electrode induction melting gas atomization — with water atomization as the alternative configuration for lower-cost, high-volume, irregular powder. The metal is melted and poured through a nozzle, where a high-velocity gas or water jet breaks the stream into droplets. The droplets freeze in flight and are then separated, dried, classified and packed as a graded powder. These powders serve as the critical high-purity feedstock for advanced manufacturing sectors such as metal 3D printing (additive manufacturing), metal injection moulding (MIM) and hot isostatic pressing (HIP), along with thermal spray, brazing and press-and-sinter parts.
Product Overview
Atomization breaks a metered stream of liquid metal into droplets and freezes them in flight, and those two events decide almost everything a buyer is paying for. A jet whose dynamic pressure exceeds the melt’s surface tension and viscous resistance tears the stream apart; the droplets then radiate heat as they fall, at 10³ to 10⁵ K/s on the inert gas route and faster under water. That is why atomized powder is metallurgically different from the same alloy cast into an ingot and crushed: the secondary dendrite arm spacing collapses to the sub-micron scale and segregation is largely suppressed. The two events also compete, which is the central tension of the process — a more energetic jet makes finer droplets, but fines lose velocity fastest and can be carried back into the spray, where they weld onto larger, still-liquid droplets as satellites. A powder line is therefore specified from the powder backwards: state the D50, the oxygen ceiling and the morphology the downstream process needs, and the melting unit, nozzle, gas system, tower height and classification train follow from those answers.
There is no best route, only the route that matches the powder specification, and the choice runs in one order — morphology and oxygen first, then the particle size cut, then cost. Water atomization uses high-pressure water, conventionally 50–150 MPa, and produces irregular, angular-to-rounded particles with a thick surface oxide and oxygen an order of magnitude above the inert route; it costs least per kilogram and scales further than any other route, which is why structural press-and-sinter parts, friction materials and diamond-tool matrices are water-atomized. Gas atomization uses argon or nitrogen against a free-fall or close-coupled stream to give spherical particles with oxygen in the tens to low hundreds of ppm, for additive manufacturing, MIM, hot isostatic pressing and thermal spray. Two variants exist for alloys that must not see air or refractories: VIGA refines the melt under vacuum before back-filling with purified inert gas, and is the route for nickel and cobalt superalloys; EIGA melts the tip of a pre-alloyed bar with an annular coil and drops it through a gas nozzle with no crucible in the path, the standard answer for titanium, titanium aluminide and other reactive alloys. Plasma rotating electrode atomization covers the same reactive niche where coarser, very clean powder is wanted.
D50 is the number a customer specifies and the number the machine has to hold repeatably, and four groups of variables set it. On the gas side, gas velocity, pressure and temperature at the nozzle, together with the nozzle’s slit or jet geometry, dominate, because median size falls sharply as velocity and dynamic pressure rise. On the melt side, flow rate, nozzle bore, superheat and the alloy’s own surface tension and density push the other way, since a larger bore, a higher flow rate and a lower superheat all give coarser powder. The gas-to-metal ratio is the strongest single lever: published data show that a one-unit increase raises the usable yield of the target cut by roughly 6%, which is why gas consumption and powder yield are the same commercial question. Machine geometry then sets the regime, with close-coupled nozzles giving a high fine-particle yield and free-fall nozzles giving higher throughput but a coarser product. D50 cannot be set in isolation, so a line is quoted with the process window that produced the promised cut, and the span matters as much as the middle — a laser powder-bed printer buys a narrow distribution with a low coarse tail.
Shape and oxygen are decided by the same window of liquid time. A droplet still liquid while surface tension dominates relaxes into a sphere, whereas one already partly solid keeps the shape it was torn into; every second spent liquid is an opportunity to oxidise, and the oxide skin is what stops a droplet spherifying; and gas recirculation carries fines back into the atomization zone, where they weld onto larger, still-liquid droplets as satellites that additive manufacturing specifications reject. Round particles flow and pack better, reaching around 74% of theoretical density against roughly 68% for irregular powder. Oxygen is largely a surface measurement, because the specific surface area of spherical particles falls as 6/(ρd) — six divided by the product of density and particle diameter — so an oxygen figure means nothing without the particle size at which it was measured. Four things set it: the residual oxygen in the chamber at solidification, which is why vacuum chambers are pumped and back-filled to well under 100 ppm for reactive alloys; the atomizing medium, since inert gas leaves a thin protective oxide while water oxidises the surface chemically, so water-atomized copper carries a Cu₂O layer and normally receives a reduction anneal in hydrogen or hydrogen-nitrogen before structural use; the time and temperature the metal spends liquid; and the handling after the tower, because powder dried, sieved, stored or packed in air picks the oxygen back up.
Atomization is one unit operation, and it is worth being precise about what it does not do. Melting liquefies and homogenises the charge, atomization breaks that melt into droplets and freezes them, and casting an ingot instead solidifies the same melt into a solid body for sale or further working; none of the three changes the alloy, so a line that accepts a 99.5% charge delivers a 99.5% powder, correctly converted into a free-flowing, graded and documented product. Smelting and refining are different in kind, because they free the metal from gangue or partition impurities and raise grade, and both sit outside this line — documented on the smelting furnace page and in the precious metal hydrometallurgical refining plant family. The feed is therefore metal that has already been made right: ingot and master alloys, clean sorted scrap and returns of known grade, or metal recovered by precious metal recovery and extraction system. Two composition effects must be planned for rather than assumed away — low-boiling elements such as zinc in brass can be lost to fume during melting and atomization, and reactive elements oxidise if the atmosphere is not controlled.
The line is built in formats rather than in one size: a laboratory and research line for alloy development and particle size screening, a pilot-production line for a new powder product or a captive MIM or additive-manufacturing feedstock operation, and a production line configured around the target cut, the tower size and the annual tonnage, normally with gas recovery, off-cut recycle and automated powder handling. Any of the three can be supplied as a gas, water, VIGA or EIGA line. Within the YuSai equipment family this page is the powder route: the 1600℃ medium frequency melting furnace covers the melting duty that feeds it, the high frequency smelting furnace and 1600℃ induction heating furnace cover compact and laboratory melting where melt volume is small, the vacuum ingot casting machine is the alternative this line competes with, and the gold electrolytic cell is where metal is taken to high purity before it is melted and atomized.
Application Scenarios
Additive manufacturing and 3D printing. Spherical gas-atomized powder in the laser powder-bed window of roughly 15–45 µm, the electron-beam window of roughly 45–106 µm and the directed-energy-deposition window of roughly 45–150 µm for stainless steels, tool steels, maraging steels, nickel superalloys, cobalt-chrome, aluminium alloys, titanium alloys and copper alloys. The line is configured around the cut the printer needs, because on a laser powder-bed machine the D50 is a process parameter and the coarse tail is a defect source.
Metal injection moulding (MIM). Fine spherical or near-spherical powder with a high tap density and a D90 typically at or below about 22 µm, which is the feedstock that lets a moulded part sinter to near-full density with isotropic shrinkage. MIM is the application where morphology and packing density matter more than median size, and where the water route reaches its limit and the gas route or a post-processing combination is specified instead.
Hot isostatic pressing and near-net-shape consolidation. Clean, low-oxygen powder for capsules and for HIP-consolidated billets, including superalloy, titanium and steel powders that are pressed to full density rather than melted again.
Thermal spray and hardfacing. Coarse, flowable cuts — commonly 45–106 µm and above — for plasma, HVOF and flame spraying of wear-resistant and corrosion-resistant coatings, including MCrAlY bond coats, carbide-bearing coatings and hardfacing alloys for valve, pump and roll protection.
Press-and-sinter powder metallurgy. Water-atomized irregular powders of iron, low-alloy steel, stainless steel, copper and copper alloys for structural parts, self-lubricating bearings, filters and friction components. The irregular shape and the rough surface oxide are the reason these powders press into a green compact with adequate green strength — an advantage the spherical route cannot replace.
Brazing and soldering powders and pastes. Copper, silver-copper eutectic and silver-copper-phosphorus alloys, nickel-based brazing alloys and tin-based solders, supplied in fine cuts for paste manufacture and for preform production. Precious-metal brazing alloys are normally gas atomized so the paste behaves predictably through a dispensing nozzle.
Electronic and thick-film pastes. Silver, gold, palladium and silver-palladium powders for conductive pastes, multilayer ceramic electrodes and electronic joining, where particle size distribution and surface chemistry control the paste rheology and the fired film’s conductivity.
Precious-metal powder for dental and jewellery work. Gold, silver, platinum and palladium alloys atomized into free-flowing powder for dental CAD/CAM powder beds, for alloy powder blends and for metallurgy where a homogeneous alloy powder is easier to weigh and dispense than a cast pellet.
Diamond tooling and hard-material matrices. Cobalt, copper, bronze, tungsten-carbide and iron-copper powders used as the matrix in diamond-impregnated segments and beads for stone cutting and drilling, with the powder’s compressibility controlling segment porosity and wear behaviour.
Magnetic and soft-magnetic materials. Neodymium-iron-boron and samarium-cobalt alloy powders for bonded and sintered magnets — atomized under inert gas with passivation, because these alloys are pyrophoric when fine — and iron-silicon and iron-silicon-aluminium soft-magnetic powders for inductor cores and electromagnetic shielding.
Metal catalysts and chemical intermediates. Nickel, copper, cobalt and precious-metal powders used as catalysts, as precursors for chemical synthesis and as carriers, where surface area and cleanliness are the specification and the atomized powder’s oxidation state has to be controlled.
Alloy development, research and teaching. Laboratory and pilot lines used by universities, institutes and alloy developers to make a few kilograms of a new composition and test it as powder, rather than sending it out and waiting for a campaign slot.
Captive powder supply inside an existing plant. A foundry, refiner, additive-manufacturing service or dental laboratory that currently buys powder and wants to close the loop on its own returns and off-cuts, converting them back into specification powder on its own site instead of selling scrap.
Recycling of powder off-cut and process returns. Oversize and out-of-specification fractions returned to the melt, and used powder withdrawn from a printer or a moulding line, recovered as powder rather than downgraded to scrap.
Applicable Raw Materials
This line atomizes a prepared melt. In practice that means the following feed classes; the form the charge arrives in decides the melting and charging arrangement, not the atomizer.
Pure metal ingot, cathode and bar. Electrolytic copper cathode, nickel cathode, aluminium ingot, zinc and tin ingot, precious-metal bar and high-purity metal bar. Input: solid metal of declared analysis, sized to the crucible; for the EIGA route, a pre-alloyed bar of the specified diameter that becomes the electrode.
Master alloys and alloying additions. Ferro-alloys, nickel-chrome, aluminium-manganese, copper-beryllium master and grain refiners, charged to bring the melt to the target composition before atomization. Input: solid, dry, sized to dissolve in the bath rather than float on it.
Clean scrap, foundry returns and process off-cut. Sorted stainless and alloy steel returns, superalloy scrap, cobalt-chrome machining swarf, copper and brass off-cuts, precious-metal bench scrap and spent targets. Input: solid metal, sorted by declared grade, degreased and free of coolant, paint, plating or attached non-metal.
Powder off-cut and used powder returned to the melt. Oversize and out-of-specification fractions, sieve rejects, used printer powder and MIM feedstock returns. Input: dry, free-flowing metal powder or briquetted powder, charged so it does not dust or bridge.
Sponge, reduced powder and cemented metal. Metal produced by reduction, precipitation or cementation — sponge, reduced oxide, cemented copper or cemented precious metal. Input: solid, dried and briquetted where necessary; normally the product of a precious metal hydrometallurgical refining plant or of an upstream reduction step.
Metal concentrate recovered from recycling. The metal-rich fraction from electronic scrap, circuit boards, catalysts and solar-panel processing after mechanical separation and metallurgical enrichment. Input: solid, dry, metal-state concentrate already separated from the non-metallic fraction, typically the output of a precious metal recovery and extraction system.
Precious-metal and speciality metal feed. Gold, silver, platinum, palladium and their alloys, doré, and high-purity metal for electronic, dental and brazing powders. Input: solid metal, with the crucible and the atomizing medium chosen so that the metal is not contaminated by either.
Material families and the route each is normally atomized by:
- Iron and low-alloy steel, stainless steel (304, 316L, 17-4PH, 430), tool and die steel, maraging steel. Gas route for AM and MIM grades; water route for press-and-sinter grades. Nitrogen is often acceptable as the atomizing gas for iron-based alloys; argon is used where nitrogen pickup must be avoided.
- Nickel- and cobalt-base superalloys (Inconel 625, 718, Hastelloy, CoCrMo, Stellite). VIGA for cleanliness and low gas content; gas route for less demanding grades. These alloys are the classic VIGA customer.
- Titanium, titanium aluminide and other reactive alloys. EIGA or VIGA, or plasma. Water atomization is not an option, and open-air gas atomization is not an option either.
- Aluminium and aluminium alloys. Gas route under inert atmosphere, with the explosion-proof and inerting design that fine aluminium powder requires.
- Copper and copper alloys. Water route for the bulk powder-metal and friction markets; gas route for additive manufacturing, brazing and electronic-paste grades. Copper’s high thermal conductivity makes it one of the harder powders to make spherical, which is why the gas route for copper is specified around gas pressure and superheat together.
- Brass and other zinc-bearing alloys. Atomizable, but zinc’s low boiling point means it fumes and the powder loses zinc against the melt analysis. The line is configured with the extraction and the melt practice to hold analysis, and the loss is measured rather than assumed.
- Nickel-titanium and shape-memory alloys. VIGA or EIGA, with composition control tight enough to hold the transformation temperature.
- Tin, lead, bismuth and low-melting solders. Water or gas route, at low superheat, with dust and fume extraction specified for the alloy’s oxide and vapour behaviour.
- Neodymium-iron-boron, samarium-cobalt and other rare-earth magnet alloys. Inert-gas route with inert powder handling and passivation, because these powders are pyrophoric.
- Tungsten-copper, molybdenum-copper and other composites. Atomized as pre-alloyed or blended as required, with the higher melting constituent setting the melting arrangement.
- High-entropy alloys, amorphous and soft-magnetic alloys, and other developmental compositions. Gas or VIGA route, usually on a pilot line where composition flexibility matters more than tonnage.
Not accepted. The line is a powder-making line fed with metal, and its boundary is stated up front.
- Ores, concentrates, calcines, sulphides, slags, dross, ash and baghouse dust. These are not metal yet and must be smelted or leached first — see the smelting furnace page for the boundary between making metal and making powder from metal.
- Leach solutions, pregnant liquors, plating baths, spent electrolytes and any wet chemical feed. These belong in a hydrometallurgical, cementation or electrowinning circuit.
- Wet filter cake, wet slime and undried residue. Water in a 1500 °C crucible or in the atomization chamber is a steam explosion, not a process.
- Oil-, coolant- or paint-contaminated swarf and turnings, and material with attached plastic, rubber or fabric. The organics decompose into the melt and into the chamber atmosphere and contaminate the powder.
- Plastics, rubber, wood, glass, ceramics and refractory rubble. There is no metal to atomize.
- Mercury, cadmium-bearing feed without dedicated design, cyanide salts, pyrotechnic and explosive-containing material, and radioactive material.
- Sealed or closed containers of any kind — aerosol bodies, gas cylinders, sealed tubes, batteries and electronic assemblies. A closed body in a molten bath bursts.
- Fine reactive powder (aluminium, magnesium, titanium, rare-earth) handled in air without inerting and passivation. Not a material problem but a handling design requirement, and one that is specified rather than assumed.
Finished Products
Spherical metal powder in the specified cut. The primary product: gas-atomized powder classified into the particle size window the customer’s process uses, with the D10, D50 and D90 stated on the certificate rather than left to the batch. Output: packed, inerted, graded powder in the agreed cut.
Irregular water-atomized powder for press-and-sinter. Angular to rounded powder with the rough surface and the compressibility that structural powder metallurgy depends on, supplied after dewatering, drying, reduction annealing and sieving. Output: dry, free-flowing, reduced powder in the agreed sieve fraction.
Reactive-alloy powder made without crucible contact. Titanium, titanium aluminide, zirconium and refractory-alloy powder produced by the EIGA or VIGA route, with no ceramic contamination path and with the oxygen and gas content that only a vacuum line achieves. Output: inerted spherical powder in sealed containers.
Brazing, soldering and paste-grade powder. Fine cuts of silver-copper, silver-copper-phosphorus, nickel-based and tin-based alloys for paste manufacture, with the particle size distribution set for the dispensing system the customer runs. Output: fine dry powder or paste-grade powder in sealed packaging.
Precious-metal and electronic-grade powder. Gold, silver, platinum, palladium and silver-palladium powders for conductive pastes, dental use and joining, with the surface chemistry controlled for the paste system. Output: assayed precious-metal powder with a declared particle size distribution.
MIM and AM feedstock powder. Powder produced to a printer’s or a moulding line’s feedstock specification, including the tap density, Hall flow rate and oxygen figure the customer’s incoming inspection applies. Output: feedstock powder with a full incoming-inspection data set.
Graded fractions alongside the primary cut. Atomization produces a distribution, not a single size, so a campaign yields the target cut plus an oversize fraction and a fines fraction. The oversize fraction is returned to the melt and recycled; the fines fraction is a saleable product in its own right for some applications and a recycle stream for others. Output: a defined split of every campaign, with each fraction weighed and assayed.
A documented mass balance. Charge weight, alloy analysis, melting and holding data, atomization parameters, gas or water consumption, fraction weights and the reconciled difference. Output: an auditable record that reconciles melt in against powder out per cut — the number that decides whether the line is profitable.
A batch certificate of analysis. Particle size distribution by laser diffraction together with sieve data, oxygen content, apparent and tap density, flow rate, morphology and chemistry, referenced to the retained sample. Output: the certificate the customer’s incoming inspection accepts, traceable to a retained sample of the same batch.
Not a product of this line: a change in composition or grade. The line converts a melt into powder of that melt. It does not remove impurities, it does not raise purity, and it does not correct a composition error. If the melt enters at 99.5%, the powder leaves at 99.5%; if a reactive element burns off in the melt, the powder carries the loss. Composition is made upstream — in melting, in smelting, and in refining and electrolysis — and the atomizer is judged by how faithfully it carries that composition into a free-flowing, graded, documented powder.
Atomization Powder Making Equipment Process Flow
The nine stages below describe one atomization campaign, from an assayed feed to packed graded powder. Each stage states its own output, so the sequence can be audited step by step. The vacuum stage applies to the vacuum and inert-gas routes; on the open gas and water routes the same stage is the atmosphere and pressure preparation of the chamber.
Steps 1 — Feed Assay and Alloy Charge Make-Up. The feed is assayed, classified by grade and weighed, and the charge is built to the alloy specification with its master alloys and additions. Any material outside the accepted classes, any wet, oily or sealed item, and any unknown grade is removed here. Output: a certified charge sheet with weights, analyses and the target composition the melt has to hit.
Steps 2 — Induction Melting and Superheat Control. The charge is melted in an induction furnace, alloyed and brought to the superheat the atomization schedule requires — a temperature above the alloy’s liquidus that keeps the stream fluid and stable at the nozzle without raising gas pickup and oxidation more than necessary. Temperature is measured continuously and the melt is stirred and homogenised before sampling. Output: a homogeneous melt at the specified superheat, with a recorded temperature trace and a retained melt sample.
Steps 3 — Chamber Evacuation and Inert Backfill. On the vacuum routes the melting chamber is evacuated and the leak rate verified, the melt is refined at low pressure to strip dissolved oxygen, nitrogen and hydrogen, and the chamber is back-filled with purified inert gas. On the open gas and water routes the chamber is purged to the specified oxygen level and the atomizing fluid supply is brought to pressure. Output: a sealed, leak-tested chamber with the atmosphere and pressure the powder specification requires.
Steps 4 — Tundish Heating and Melt Metering. The melt is transferred to a heated tundish, held at temperature, and metered through the melt delivery nozzle. Nozzle bore, tundish temperature and the head of metal above the nozzle set the melt flow rate, which is one of the two inputs to breakup and therefore to median particle size. Output: a steady, vertical, metered melt stream with a known flow rate.
Steps 5 — Jet Breakup at the Atomizer Nozzle. High-velocity gas or high-pressure water strikes the melt stream and the jet’s dynamic pressure overcomes the melt’s surface tension, disintegrating the stream into a spray of droplets. Gas-to-metal ratio, gas pressure and temperature, nozzle geometry and superheat are all held at the values the recipe specifies. Output: a controlled droplet spray with the size distribution the campaign was scheduled to produce.
Steps 6 — Droplet Free Flight and Solidification. The droplets fall through the atomization tower and freeze in flight, at cooling rates in the order of 10³ to 10⁵ K/s on the gas route and higher on the water route. Tower height gives the residence time needed for full solidification before wall contact, and a controlled downward gas stream suppresses the recirculation that produces satellites. Output: fully solidified powder particles of controlled size, shape and microstructure.
Steps 7 — Powder and Gas Separation with Recovery. The powder–gas stream leaves the tower and is separated in a cyclone and a filter system, with the gas cooled, cleaned and either vented or recovered and recycled back to the atomizing circuit. On the water route the powder–water slurry is separated instead, and the water is filtered, cooled and recirculated. Output: collected powder in a hopper under controlled atmosphere, a clean exhaust, and a defined consumption figure for gas or water per kilogram of powder.
Steps 8 — Drying, Reduction and Classification. Collected powder is dried — under vacuum or in an inert dryer rather than in open air — and on the water route given a reduction anneal in hydrogen or a hydrogen-nitrogen atmosphere to remove the surface oxide that the water route produces. The powder is then sieved and air-classified into the target cut, with the oversize and fines fractions separated and weighed. Output: dry, de-oxidised where required, classified powder in the target cut, plus weighed oversize and fines fractions.
Steps 9 — Qualification, Blending and Packing. Each fraction is sampled and tested — particle size distribution, oxygen, density, flow, morphology and chemistry — blended where a specification calls for a homogenised lot, and packed into sealed containers under inert gas or with controlled passivation for reactive alloys. Batch records, the retained sample and the certificate of analysis are issued with the shipment. Output: packed, certified, traceable powder plus the campaign mass balance and the retained sample.
Product Structure (Main Equipment)
Induction melting furnace. The melting and alloying unit at the head of the line: a crucible-type induction furnace for the open routes, and a vacuum induction melting furnace with its own chamber, charging lock and alloying system for the VIGA route. Its duty in this line is expressed in powder terms — kilograms of melt available per campaign, a superheat that keeps the stream stable at the nozzle, and a melt clean enough that the nozzle is not the limiting factor in the campaign. The melting unit itself is documented on the 1600℃ medium frequency melting furnace page; here it is specified as the module that feeds the tundish.
Medium-frequency power supply and capacitor cabinet. The IGBT power conversion and the tank capacitor bank that drive the induction coil. In a powder line the power supply also has to hold temperature steady through the pour: superheat that drifts during atomization shows up directly as a drift in median particle size and in the fine fraction of the batch.
Electrode feed and annular coil (EIGA configuration). The crucible-free alternative: a pre-alloyed bar is fed downward and its tip is melted by an annular induction coil, with a typical electrode geometry of the order of 150 mm diameter by 1000 mm long and a charge weight that can range from a few kilograms to a few tonnes. Because the melt never contacts a crucible or a ceramic nozzle, there is no refractory contamination path — which is the entire reason this configuration exists for titanium and reactive alloys.
Vacuum system. Rotary and booster pumps, diffusion or dry high-vacuum stages, gauges, and a leak-test routine. The system is specified by ultimate vacuum and by pressure rise rate, because pressure rise rate — not the ultimate figure — is what proves a chamber can hold a clean atmosphere through a campaign. A working figure is an ultimate vacuum in the 10⁻³ Pa range with a pressure rise rate of a few pascals per hour, verified before every campaign on the vacuum routes.
Inert gas supply, purification and recovery. Gas storage, pressure regulation, flow metering and a purifier that removes oxygen and moisture from the gas before it reaches the nozzle, with a purity of 99.999% as the usual working grade for argon and a dew point well below zero. On production lines a recovery and recycling system is normally specified: gas is recovered from the filter exhaust, cleaned and returned to the circuit, because argon is the single largest consumable in gas atomization and gas consumption per kilogram of powder is a direct cost line.
Heated tundish, stopper rod and melt delivery nozzle. The tundish holds the melt at temperature under the atmosphere and meters it through the melt delivery nozzle, typically with an induction-heated lining in the 20–45 kW range to hold the melt within a narrow temperature band. Nozzle bore sets the melt flow rate and therefore one side of the breakup balance; nozzle material and bore geometry are selected for the alloy and for the required particle size, and the nozzle is the consumable that wears. Twin-tundish arrangements are available so that a nozzle failure or a freeze-off is met by switching to the second tundish instead of ending the campaign.
Atomizer assembly. The part that actually makes the powder — the gas nozzle or the water nozzle set that surrounds or meets the melt stream.
- Close-coupled atomizer — gas jets positioned immediately below the melt delivery point, giving strong momentum transfer, a high fine-particle yield and the finest powder of the gas configurations, at the cost of a tighter thermal regime at the nozzle.
- Free-fall atomizer — the melt stream is allowed to form a longer jet before the gas reaches it, giving higher throughput and a safer, more forgiving nozzle environment, with a coarser product.
- Nozzle geometry — annular slit, discrete jet ring or convergent-divergent designs, selected with bore diameter and jet angle to suit the alloy, the superheat and the target cut. Gas pre-heating is available as an option: heating the atomizing gas to several hundred degrees with argon lowers the mean particle size, or holds the mean size at a lower gas consumption.
- Water nozzle set — high-pressure water jets at pressures conventionally in the 50–150 MPa band, with the accumulator, valve and pump arrangement that delivers a steady pressure pulse to the spray. Pressure stability is the water route’s equivalent of a steady gas pressure: a fluctuating jet produces a fluctuating particle size distribution.
Atomization tower and process chamber. The vessel in which the droplets freeze. Height is set by the fall time needed for full solidification before wall contact; diameter is set by the spray cone so that the majority of droplets do not reach the wall while still liquid; the chamber is water-jacketed so wall deposits can be released rather than built up. A controlled external gas stream is introduced at the top of the tower to establish a secondary downward flow, which suppresses the recirculation of fines back into the spray and is the structural countermeasure to satellite formation. Sight ports, an oxygen analyser and a pressure tap complete the chamber.
Cyclone separator, gas cooler and filter. The powder–gas separation train: the cyclone removes the bulk of the powder and drops it into a collection hopper, the gas cooler brings the gas temperature down, and the bag or cartridge filter removes the fine carry-over. Filter selection and fire protection are part of the powder-safety design, because fine metal powder collected in a filter is a combustible dust.
Powder collection, transfer and inerting. Collection hoppers, transfer lines, valves and packaging stations designed as an inerted closed loop: powder is moved and stored under inert gas, with oxygen monitoring and pressure balancing, so the low oxygen content achieved in the chamber is not lost in the aisle. For reactive alloys the loop also includes passivation before exposure to air.
High-pressure water system (water route). Pump set, accumulator, high-pressure piping and the nozzle manifold, plus the water treatment loop — settling, filtration, cooling and recirculation — that keeps the atomizing water clean and at temperature. Water quality and pressure stability are part of the powder specification on this route, not plant services.
Dewatering, drying and reduction equipment (water route). A settling tank, filter press or vacuum belt for dewatering; a vacuum, belt or rotary dryer; and a reduction furnace in hydrogen or a hydrogen-nitrogen atmosphere for removing the surface oxide from iron, steel and copper powders before they are sold for press-and-sinter use. On the gas route the equivalent section is a dryer and an inert powder cooler.
Sieving, air classification and blending. Vibratory or ultrasonic sieving for the coarse end, air classification for the fine end, and a blender for homogenising a lot to specification. Classification is what turns a distribution into saleable cuts, and its efficiency is one of the two numbers that decide the line’s real yield — the other being the atomizer’s own fine-particle yield.
Powder packing station. Sealed drum or bag filling under inert atmosphere, with weighing, labelling and, for reactive powders, passivation and an inert-gas blanket. Packing is where the batch certificate is attached to the container and where the traceability chain closes.
Control system, instrumentation and data recording. A PLC with an industrial control computer, driving the melting and atomization recipe from one screen: pyrometer and thermocouple temperature inputs, gas or water pressure and flow, chamber pressure and oxygen, gas-to-metal ratio calculated per second, and the batch log. Recipes are saved and recalled per alloy and per cut, and the system records the process curves — pressure, temperature, flow and oxygen — for each campaign, which is what makes a batch reproducible and a dispute resolvable.
Safety and protection systems. Water-flow and water-temperature interlocks on the coil, capacitors and power supply; over-pressure and relief protection on the gas circuit; oxygen monitoring with inert-gas purge and trip logic on the reactive routes; bonding, grounding and conductive flooring for combustible dust; temperature monitoring on the filter and the collection hopper; and an emergency stop chain that dumps power and isolates gas. For aluminium, titanium, rare-earth and other reactive powders the inert loop and the safety case are designed as one system rather than assembled from standard parts.
Consumables and wear parts. Melt delivery nozzles and gas nozzles, crucibles and tundish linings, filter elements, seals and gaskets, cyclone liners and sieving screens. The nozzle is the wear item that most directly drives both campaign cost and powder consistency, because a nozzle that has abraded open produces a coarser powder from the same recipe, so nozzle life is tracked per campaign rather than replaced on a calendar.
Documentation and traceability. Charge sheet, melt analysis, atomization recipe and process curves, fraction weights, test results and the retained sample are held per batch, so a packed container can be traced back to the melt, the nozzle and the recipe that produced it.
Product Features
- Powder-first specification. The line is quoted from the powder requirement backwards — target cut, D50 and span, oxygen ceiling, morphology, flow and annual tonnage — so the melting unit, nozzle, gas system, tower and classification train are sized around the powder you have to sell rather than around a furnace that happens to be in the catalogue.
- All four routes from one engineering team. Gas, water, VIGA and EIGA configurations are built on the same melting and metering discipline, so the route recommendation follows from the alloy and the application instead of from what one product line is able to supply.
- D50 quoted with the process window that produces it. A median particle size is meaningless without the gas-to-metal ratio, the pressure, the superheat and the nozzle that achieved it, so the process conditions travel with the guarantee.
- Yield accounted per fraction, not as a single flattering number. Every campaign records the target cut, the oversize fraction returned to the melt and the fines fraction, and reconciles the split against the charge weight, so the economics of the line are visible per batch rather than estimated per year.
- Oxygen controlled as a design variable. Vacuum level and leak rate, gas purity and dew point, chamber oxygen monitoring, inert powder transfer, drying practice and reduction annealing on the water route are specified together, because the oxygen figure on the certificate is the sum of all of them.
- Satellite formation addressed structurally. Tower height and diameter, close-coupled or free-fall nozzle choice, and a controlled top-down gas flow in the chamber are selected to suppress the recirculation that welds fines onto larger droplets — the defect that AM powder specifications reject.
- Hot gas atomization available. Pre-heating the atomizing gas with argon reduces the mean particle size, or holds the mean size while reducing inert gas consumption, and it narrows the temperature difference between gas and melt, which stabilises the spray.
- Gas recovery and recycling on production lines. The largest consumable in gas atomization is the gas itself, so recovery, cleaning and recirculation are engineered in rather than offered as an afterthought.
- Redundant tundish option. A second heated tundish with its own nozzle is available so that a freeze-off or a nozzle failure costs a switchover rather than the remainder of the campaign and the melt in the crucible.
- Every campaign is reproducible from a saved recipe. Alloy recipes, pressure and temperature set points, gas-to-metal ratio targets and alarm limits are stored and recalled, and the process curves are logged per batch — so a successful campaign can be repeated, and a drifting one can be diagnosed from its own record.
- Powder-safety engineering for reactive materials. Inerted handling, oxygen monitoring, passivation, bonding and grounding, and filter fire protection are treated as part of the machine on reactive-alloy lines, because aluminium, titanium and rare-earth powders are a genuine combustible-dust and pyrophoric hazard.
- One supplier across melt, powder and refining. The same engineering team specifies the melting unit, the atomizer, the classification train and the refining and casting equipment on either side, so the melt cleanliness that the nozzle needs, the composition the powder must carry and the metal balance through the whole route are engineered as one chain rather than negotiated between three vendors.
- Modular build and serviceable in place. Melting furnace, power supply, tundish and nozzle assembly, atomizer, tower, separation train, drying and classification modules and the control system are separate assemblies, so shipment is straightforward and a failed module is replaced rather than rebuilt.
- Acceptance testing with real powder. Commissioning is not complete until the line has atomized the customer’s own alloy and produced a batch inside the agreed particle size, oxygen and flow specification — the test that decides whether the line works, and the one a paper specification cannot substitute for.
Technical Parameters And Specifications
Table 1 — Line specification
| Parameter | Specification |
|---|---|
| Machine type | Metal powder atomization line: induction melting, heated tundish and melt delivery nozzle, atomizer, atomization tower, powder separation, drying, classification and packing |
| Routes available | Inert gas atomization, water atomization, vacuum induction melting gas atomization (VIGA), electrode induction melting gas atomization (EIGA) |
| Rated melting temperature | Up to 1750 °C on the open gas and water routes; higher on the vacuum and electrode routes, configured against the alloy liquidus plus the required superheat |
| Superheat window | Configured per alloy and per route; conventionally of the order of 50–150 °C above the liquidus on the gas route, and higher on the water route to keep the stream fluid at high jet pressure |
| Melt capacity per campaign | Configured per project against the alloy, the target cut and the campaign length; a laboratory line may run a few kilograms and a production line several tonnes |
| Feed preparation | Charge drying and briquetting where the feed is fine, degreasing where the feed is scrap, and analysis before the charge is closed |
| Atomizing gas | Argon or nitrogen, purity 99.999% with an in-line purifier; pre-heated gas option up to several hundred degrees centigrade with argon |
| Gas pressure at the nozzle | Configured against the nozzle design, conventionally up to the order of 9 MPa for close-coupled inert gas atomization |
| Atomizing water pressure | High-pressure water, conventionally in the 50–150 MPa band, delivered through an accumulator for pressure stability |
| Gas-to-metal ratio | Set by nozzle design and gas pressure, and quoted together with the powder guarantee rather than published as a fixed band |
| Vacuum system | Ultimate vacuum in the 10⁻³ Pa range with the leak rate verified by pressure rise rate before each campaign on the vacuum routes |
| Chamber oxygen before melt-down | Purged to below 100 ppm residual oxygen for reactive and highly oxidisable alloys |
| Tundish heating | Induction-heated tundish, conventionally in the 20–45 kW range, holding the melt within a narrow temperature band through the pour |
| Melt delivery nozzle | Bore and material selected against the alloy and the target cut; a consumable, with life recorded per campaign |
| Atomizer configuration | Close-coupled or free-fall gas nozzle with annular slit or discrete jet geometry; high-pressure water nozzle set on the water route |
| Atomization tower | Height set by the solidification fall time, diameter set by the spray cone, water-jacketed, with a controlled top-down gas flow to suppress satellites |
| Powder–gas separation | Cyclone, gas cooler and bag or cartridge filter, with gas recovery and recycling specified on production lines |
| Powder–water separation | Slurry separation with water treatment, filtration, cooling and recirculation on the water route |
| Drying | Vacuum, belt or rotary drying under inert or controlled low-oxygen conditions |
| Reduction annealing | Hydrogen or hydrogen-nitrogen reduction furnace on the water route for iron, steel and copper powders |
| Classification | Vibratory or ultrasonic sieving plus air classification into saleable cuts, with oversize and fines weighed separately |
| Particle size capability | Quoted concretely per route and per cut; representative working windows are given in Table 3 |
| Powder yield | Quoted per fraction against the target cut, with oversize returned to the melt and fines accounted as a separate stream |
| Inert gas consumption | Measured per campaign, conventionally of the order of several cubic metres per kilogram of powder on the gas route, reduced by recovery and recycling |
| Energy consumption | Measured per campaign; the gas route is the most energy-intensive of the routes and the water route the least |
| Powder handling | Inerted closed loop for collection, transfer, blending and packing, with oxygen monitoring throughout and passivation for reactive alloys |
| Control system | PLC with industrial control computer, recipe storage per alloy and cut, and process-curve logging per batch |
| Safety systems | Water flow and temperature interlocks, gas over-pressure protection, oxygen trip logic, filter and hopper temperature monitoring, bonding and grounding, emergency stop chain |
| Documentation | Charge sheet, melt analysis, atomization recipe and process curves, fraction weights, certificate of analysis and retained sample per batch |
| Capacity, power, footprint and utilities | Configured per project against the alloy, the target cut and the annual tonnage; the site interface list is issued with the quotation |
Values in the table describe the line as a class of machine. Final ratings — melt capacity, gas or water pressure, tower height, classification set points, cooling duty, electrical supply and the site interface — are confirmed at engineering stage against your alloy, your target cut, your feed form and your campaign schedule. Working voltage, control interface, inerting level and packaging format can be customised.
Table 2 — What each process variable sets
The columns on the right are the reason a powder line cannot be quoted from a catalogue sheet: almost every variable the operator can touch moves at least two powder properties at once, and some of those movements are in opposite directions.
| Process variable | Powder property it sets | Direction of effect |
|---|---|---|
| Gas velocity and dynamic pressure at the nozzle | Median particle size | Median size falls as velocity rises |
| Gas-to-metal ratio | Median size and fine-particle yield | The strongest single lever; published atomization data show roughly 6% more usable yield of the target cut per unit increase |
| Gas temperature, where the hot-gas option is fitted | Median size and spray stability | A hotter gas lowers the mean size, or holds the mean size while cutting gas consumption, and narrows the gas-to-melt temperature difference |
| Melt delivery nozzle bore and melt flow rate | Median size and droplet population | Coarser powder as bore and flow rate rise |
| Superheat | Median size, sphericity and oxygen | Improves stream stability and droplet sphericity up to a limit; beyond it, raises dissolved-gas pickup and oxidation |
| Alloy surface tension and density | Median size | Higher surface tension and lower density atomize coarser |
| Cooling rate, gas route versus water route | Microstructure, morphology and oxide thickness | Water cools faster, giving finer dendrite arm spacing, less spherical particles and a thicker surface oxide |
| Atomizing medium | Oxygen content and morphology | Inert gas leaves a thin largely protective oxide; water oxidises the surface and requires reduction before press-and-sinter use |
| Chamber oxygen and gas purity | Oxygen content of the powder | Directly, and it is the dominant term in the final figure |
| Tower height, spray cone and top-down gas flow | Satellite content, wall deposits and fines yield | A taller tower and a controlled downward flow reduce satellites and wall build-up |
| Atomizer type: close-coupled versus free-fall | Median size, fine yield and throughput | Close-coupled gives finer powder at a higher fine yield; free-fall gives coarser powder at higher throughput |
| Classification set point | Saleable cut and apparent density | Directly, and it fixes the split between target cut, oversize and fines |
| Drying and downstream handling atmosphere | Oxygen content after the tower | Directly; a clean chamber atmosphere can still be undone in the aisle |
| Particle size itself | Oxygen figure, flow and packing density | Specific surface area falls as 6 divided by the product of density and diameter, so oxygen and flow numbers are only comparable at the size at which they were measured |
Table 3 — Representative particle size windows by downstream process
| Downstream process | Typical working cut | Route normally used | What sets the window |
|---|---|---|---|
| Laser powder-bed fusion | 15–45 µm | Gas, VIGA, EIGA | Recoater layer thickness and the machine’s own acceptance window |
| Electron beam powder-bed fusion | 45–106 µm | Gas, VIGA, EIGA | Preheat behaviour and beam spot size |
| Directed energy deposition | 45–150 µm | Gas | Powder feed nozzle and feed rate |
| Metal injection moulding | D90 at or below about 22 µm | Gas, VIGA | Sintering shrinkage and mould filling |
| Hot isostatic pressing and near-net shape | 45–106 µm; wider cuts available | Gas, VIGA, EIGA | Capsule filling and packing density |
| Thermal spray and hardfacing | 15–45 µm and 45–106 µm and coarser | Gas, water | Spray gun type and target coating thickness |
| Press-and-sinter powder metallurgy | sieve fractions from about 45 µm upward | Water | Compressibility and green strength |
| Brazing and soldering paste | fine cuts, commonly below 45 µm | Gas, water | Paste rheology and the dispensing system |
| Electronic and thick-film paste | fine cuts, commonly below 45 µm | Gas, precious-metal route | Paste printing behaviour and fired film conductivity |
| Diamond tooling and friction materials | coarse, commonly 45–180 µm | Water | Matrix packing and pressing behaviour |
| Bonded and sintered magnets | fine cuts, handled and packed under inert gas | Gas, inert route | Magnetic alignment and sintering |
The windows above are working ranges, not guarantees, and no two machine builders or printer manufacturers draw them identically. The cut the line is actually configured for is the one on your incoming-inspection sheet.
Table 4 — Route selection
| Route | Atomizing medium | Particle shape | Oxygen level | Throughput | Alloys it suits | Principal cost driver |
|---|---|---|---|---|---|---|
| Water atomization | High-pressure water, 50–150 MPa | Irregular to rounded | Highest; the surface oxide requires reduction for press-and-sinter grades | Highest of the four | Iron, low-alloy and stainless steel, copper, brass, bronze, brazing alloys, solders | Water, drying and reduction energy |
| Inert gas atomization | Argon or nitrogen, up to the order of 9 MPa | Spherical to near-spherical | Low; tens to low hundreds of ppm for most alloys | Medium | Stainless and tool steels, maraging steel, superalloys, copper, aluminium, precious metals | Inert gas consumption and fine-particle yield |
| VIGA | Inert gas after vacuum melting and refining | Spherical | Lowest; the melt is degassed and refined under vacuum before atomization | Lowest of the four | Nickel and cobalt superalloys, titanium alloys, steels requiring cleanliness | Vacuum, crucible campaign and cycle time |
| EIGA | Inert gas, crucible-free bar melting | Spherical | Very low; no crucible or ceramic contact | Set by bar feed rate | Titanium, titanium aluminide, zirconium, niobium, reactive and refractory alloys | Electrode supply and feed rate |
| Plasma rotating electrode | Plasma arc against a rotating electrode | Highly spherical | Very low | Low | Titanium and refractory alloys needing coarse clean powder | Power and electrode cost |
Table 5 — Batch qualification tests
| Test | Method | What it decides |
|---|---|---|
| Particle size distribution, D10, D50, D90 and span | Laser diffraction to the standard laser-diffraction method, reported with sieve data | Whether the batch sits inside the customer’s printing or moulding window |
| Sieve analysis | Test sieves, normally including the 45 µm screen | The coarse end of the distribution and the fraction split for the mass balance |
| Oxygen content | Inert gas fusion analysis, reported at the stated particle size | Whether the powder will run in an additive machine or needs reduction |
| Apparent density | Standard funnel method for apparent density | Packing behaviour and die or capsule filling |
| Tap density | Standard tap density method | Feedstock behaviour; critical for metal injection moulding |
| Flow rate | Hall flow through a calibrated funnel, with Carney flow for fine powders | Whether the powder feeds a recoater, a dispenser or a moulding machine |
| Morphology, sphericity and satellite count | Scanning electron microscopy with image analysis | The defect population that flow and density figures only partly capture |
| Chemistry and alloy verification | Spectrometry, with combustion analysis for carbon and sulphur | Whether the powder carries the composition of the melt |
| Moisture and loss on drying | Gravimetric drying | Whether the powder is dry enough to pack and to process |
| Surface oxide and reduction state | Metallographic and chemical assessment | Whether a water-atomized batch has been reduced adequately for structural use |
| Contamination check | Microscopy, with magnetic or sieve-based checks, where specified | Crucible, refractory, nozzle or handling contamination |
| Retained sample and traceability | A sealed retained sample held with the batch record | Whether a customer query or a dispute can be answered months later |
Configuration inputs
We configure the line from the following answers. Where an answer is not yet fixed, we run a trial or a test campaign rather than assuming a value.
- The alloy or alloys, with the target composition and the analysis tolerances.
- The target cut, with the D10, D50 and D90 and the span that the downstream process accepts.
- The oxygen ceiling of the powder specification, stated at the particle size at which it is measured.
- Morphology and flow requirements: sphericity, satellite limit, Hall or Carney flow, apparent and tapped density.
- The feed form as it will actually arrive — ingot, cathode, bar, electrode, clean scrap, returns, sponge or reduced powder.
- Campaign size in kilograms of melt, and the number of campaigns per week or per month.
- The route the alloy requires, or the route question you want us to answer with the data behind it.
- Annual or monthly tonnage of saleable powder, split by cut.
- Site conditions: electrical supply and transformer capacity, inert gas supply and whether recovery is wanted, cooling water, floor loading, and the height available for the atomization tower.
- Local requirements on dust explosion, emissions, noise and working atmosphere, which set the inerting level, the extraction system and the safety case.
Technical Advantages
Powder-first engineering. Most powder-line disappointments are decided at the quotation stage, when a machine is sold against an annual tonnage and a metal name without anyone asking what D50, what oxygen ceiling and what morphology the customer’s printer or moulding line will actually accept. We quote from the powder backwards and publish the process window that produces the guarantee, so the number on the contract, the number on the certificate and the number on the customer’s incoming inspection are the same number.
All four routes, one engineering discipline. Water, gas, VIGA and EIGA are different products, and a vendor that builds only one of them will recommend it for everything. Because the same team specifies all four, the recommendation follows from the alloy — whether it is reactive, whether it needs vacuum refining, whether the customer needs spherical powder or compressibility, whether the tonnage justifies gas recovery — rather than from what is easiest to sell.
Yield accounted honestly, per fraction. A powder line produces a distribution, not a single size, and the difference between a profitable line and an unprofitable one is usually the split between the target cut, the recyclable oversize and the fines. We measure that split per campaign against the charge weight, state the numbers, and design the off-cut return loop and the classification set points around it — instead of quoting a yield figure that ignores which fraction it refers to.
Oxygen engineered as a system, not as a claim. Low oxygen comes from a chain of things that must all work: a leak-tight vacuum chamber, a gas purifier, oxygen monitoring in the chamber, inert powder transfer, inert drying and, on the water route, a proper reduction anneal. Because the chain is specified end to end and the figure is measured by inert gas fusion analysis at the stated particle size, the oxygen number on our certificate is one a customer can reproduce — and a customer can compare it with any other supplier’s number on equal terms.
Satellite suppression by chamber design. Satellites are the defect that AM powder specifications reject, and they are made by gas recirculation inside the tower. Tower height and diameter, the close-coupled or free-fall nozzle choice, and a controlled top-down gas flow that suppresses the upward transport of fines are selected together, so the powder’s flowability comes from the machine rather than from downstream screening that discards the yield it was supposed to recover.
Consumables treated as the running cost they are. In this process the nozzle, the crucible and the tundish lining decide both campaign cost and powder consistency: a nozzle that has worn open gives coarser powder from an unchanged recipe. Nozzle life, bore measurement and tundish condition are tracked per campaign, spare nozzles and twin-tundish arrangements are priced with the machine, and the operator is given the replacement procedure — because a line that stops for a consumable it does not have on site is not a production line.
Gas recovery where the economics demand it. On a gas or VIGA line, the inert gas is the largest consumable, and it is also the easiest cost to attack. Recovery, cleaning and recirculation are specified on production lines so that gas consumption per kilogram of powder is a designed number rather than an invoice that arrives every month.
Reproducibility from saved recipes and logged curves. Every campaign logs pressure, temperature, flow, oxygen and the calculated gas-to-metal ratio. A good campaign can be repeated from its recipe; a drifting campaign can be diagnosed from its own curves; and a customer dispute about a batch can be settled with the record and the retained sample instead of with an argument.
Powder safety designed in for reactive alloys. Aluminium, titanium and rare-earth powders are genuinely hazardous — pyrophoric when fine, and a combustible dust in the wrong containment. Inert handling, oxygen monitoring, passivation, bonding and grounding, filter temperature sensing and fire protection are specified as part of the machine rather than left to the customer’s site engineer, and the safety case is delivered with the layout.
One supplier across the metal chain. The melting unit, the atomizer, the classification train and the refining and casting equipment either side of them come from one engineering team. That matters because the nozzle’s life depends on melt cleanliness, the powder’s composition depends on how the melt was made and sampled, and the metal balance depends on how the melt was weighed — and none of those interfaces is anybody’s responsibility if three vendors each cover one machine.
Never-out-of-envelope honesty. We will tell you when atomization is the wrong unit operation: when the feed is not metal yet and needs smelting, when it is a solution and needs hydrometallurgy, when the alloy is so reactive it needs EIGA and a bar supply you do not have, or when the cut you are asking for is outside what the route can deliver economically. Saying so at the proposal stage costs a page; saying it after installation costs a project.
Modular, serviceable, and re-configurable as your product changes. Melting furnace, tundish and nozzle assembly, atomizer, tower, separation train, drying and classification modules and the control system are separate assemblies. When the product mix moves from stainless to superalloy, or from press-and-sinter to additive powder, the change is met by re-specifying the nozzle, the tower and the classification set points rather than by replacing the line.
Service Process
1. Requirement review and route recommendation. We start from the powder and the alloy, not from a machine. Send the alloy, the target cut, the oxygen ceiling and the annual tonnage, and we answer the route question first: water for compressibility and cost, gas for sphericity and low oxygen, vacuum melting for cleanliness, crucible-free for reactive alloys. If your feed is not metal yet, or the cut you are asking for does not sit where that route can deliver it economically, we say so at this stage and tell you which unit operation comes first.
2. Powder specification and trial campaign. The powder specification is written down before the line is designed: D10, D50 and D90 with the span, oxygen at the stated particle size, morphology and satellite limits, flow and density figures, and the tests that will prove each one. Where the alloy or the cut is unfamiliar, we run a trial campaign on a pilot line rather than extrapolating from a similar powder, and the trial result becomes the basis of the guarantee.
3. Process design and configuration proposal. We return a process design: melting arrangement, tundish and nozzle selection, atomizer type and nozzle geometry, gas or water pressure and the gas-to-metal ratio target, tower height and diameter, separation and recovery arrangement, drying and reduction duty, classification set points and the control and data-logging scope. Each choice is tied to one of the powder specification numbers, so you can see why the machine looks the way it does.
4. Quotation and site interface list. A quotation is issued against the agreed configuration together with the site interface list: electrical supply and transformer capacity, inert gas supply and storage, cooling water duty, compressed air, floor loading and height requirement for the tower, extraction and emission requirements, and the layout drawing the civil and electrical works are built from. Everything outside the machine scope is named explicitly so that nothing is discovered on site.
5. Manufacture, factory assembly and factory acceptance test. The line is built modularly and assembled in the factory as far as shipment allows. Melting unit, power supply, tundish and nozzle assembly, atomizer, tower, separation train, control system and instrumentation are powered up and functionally tested, the protection interlocks are proven, and — where the customer supplies feed material — a factory acceptance test is run on your alloy so the powder specification is demonstrated before the equipment leaves the works.
6. Shipment and documentation. The line ships with the packing list, layout and foundation drawings, electrical and piping interface drawings, operating and maintenance manuals, the nozzle and tundish installation procedures, the classification set-point table, the safety documentation for reactive-powder handling and the recommended spare parts list.
7. Site installation and commissioning on your alloy. Our engineers supervise installation and carry out commissioning on site: mechanical and electrical assembly, leak testing on the vacuum routes, gas and water circuit pressure testing, tower and separation alignment, control system configuration, interlock testing, and then the first real campaigns. Commissioning is not complete until the line has produced a batch inside the agreed particle size, oxygen, flow and density specification from your own feed.
8. Operator training and handover. Operators are trained on the line they will actually run: melt preparation and superheat control, nozzle fitting and inspection, pressure and gas-to-metal ratio setting, chamber atmosphere management, classification changes, reduction and drying practice on the water route, powder sampling and testing, routine maintenance and the alarm and fault response list. Training is delivered at the machine with written procedures left with the plant.
9. Ongoing technical support and optimisation. After handover we remain the technical contact: cut changes when your product mix moves, nozzle selection as the alloy changes, yield optimisation through the gas-to-metal ratio and classification set points, oxygen reduction when a specification tightens, spare parts, and process advice on the melting and refining steps either side of the atomizer.
Warranty And After-Sales Service
What the warranty covers
The warranty covers the manufactured assemblies of the line — the induction melting unit and its power supply, the vacuum system on the vacuum routes, the tundish and its heating system, the atomizer assembly and nozzle holders, the atomization tower, the cyclone and filter train, the gas or water circuit components, the drying, reduction and classification equipment, the control system and the instrumentation — against defects in materials and workmanship arising under normal operation and correct maintenance. The warranty period and its exact scope are confirmed in the supply contract and restated on the quotation, so the terms on paper are the terms you hold.
What is excluded
Consumables and wear items are excluded, because their life is set by the alloy, the duty cycle and the operating practice rather than by the machine: melt delivery nozzles and gas nozzles, crucibles and tundish linings, filter elements, seals and gaskets, cyclone liners and sieving screens. Damage arising from operating the line outside its stated envelope — atomizing an alloy the machine was not configured for, running the chamber atmosphere outside specification, operating without cooling water or extraction, or using atomizing gas or water outside the specified purity and pressure range — is likewise outside warranty scope. Modifications made without agreement, and contamination of the line by feed material outside the accepted classes, are also excluded. We state these boundaries plainly because they are the same boundaries that decide whether the line gives you stable powder for years or months.
Spare parts
A recommended spare parts list is issued with the line and priced with the order so that it can be bought as part of the project rather than sourced in an emergency. Nozzles, crucible and tundish consumables, filter elements, seal kits and the critical control and instrumentation items are held for repeat customers, and consumable supply is planned around your production schedule — including a spare nozzle set and, where specified, a second tundish so that a nozzle failure does not end a campaign.
Remote support
Fault diagnosis and parameter advice are provided remotely from the records the line produces. Melt temperature, chamber pressure, gas or water pressure, flow, oxygen and the batch log are recorded per campaign, so a fault can usually be identified from the record rather than from a site visit — and a powder result that has drifted can often be corrected by re-setting the gas-to-metal ratio or the classification point rather than by changing hardware. Remote support also covers re-tuning recipes when the alloy or the cut changes.
Field service
Where a fault cannot be resolved remotely, field service is dispatched with the agreed response priority for your region. The service scope at handover, and the terms and response commitments of ongoing field service, are set out in the contract so that expectations are documented on both sides in advance. Site work is supported with commissioning-quality procedures, and the machine record travels with the case so that a field engineer arrives with the relevant history.
Maintenance and operating support
The manual issued with the line sets out the routine maintenance schedule: nozzle bore measurement and replacement interval, crucible and tundish lining wear checks, vacuum leak and pressure-rise testing on the vacuum routes, gas purifier and filter element replacement, oxygen analyser calibration, cooling water quality and flow verification, classification screen condition, and the protection interlock test routine. Nozzle life, filter pressure drop and batch yield are recorded per campaign so that replacement can be planned rather than reacted to.
Upgrade and re-configuration
Because the line is built modularly, a change of product is met by re-specifying rather than replacing: a different nozzle and gas pressure window for a new cut, a different tower configuration for a different fine-particle yield, a reduction furnace section added when the product moves from additive powder to press-and-sinter powder, a gas recovery system added when tonnage makes it pay, an EIGA or VIGA head added when a reactive alloy enters the range, or additional instrumentation where tighter batch documentation is required.
Contact
WhatsApp / WeChat: +8618339216321 · Email: info@yusaipreciousmetals.com · Zhengzhou, Henan, China. Enquiries are answered within 24 hours with a technical response rather than a price list — send the alloy, the target cut with its D50 and span, the oxygen ceiling and the annual tonnage, and we will answer against those numbers.
Frequently Asked Questions
What is atomization powder making equipment?
Atomization powder making equipment is a production line that converts molten metal into metal powder. A stream of liquid metal is metered out of a heated tundish through a nozzle and broken into droplets by high-velocity inert gas or high-pressure water, or by a plasma or a rotating electrode in the specialised routes. The droplets freeze in free flight inside an atomization tower, and the solidified powder is separated from the gas or the water, dried, classified into saleable cuts and packed. A complete line consists of the melting unit, the tundish and melt delivery nozzle, the atomizer, the atomization tower, the powder separation and gas recovery train, the drying and reduction equipment, the sieving and air classification section, and the control system that logs the process data for every batch.
How does gas atomization work?
A prepared melt is held at a controlled superheat and allowed to flow through a melt delivery nozzle, forming a steady vertical stream. High-velocity argon or nitrogen from the atomizer nozzle strikes that stream and its dynamic pressure overcomes the melt’s surface tension, tearing the stream into a spray of fine droplets. The droplets cool and solidify as they fall through the tower, typically at cooling rates in the order of 10³ to 10⁵ K per second, which is fast enough to suppress segregation and refine the microstructure. A cyclone separates the bulk of the powder from the gas, a filter removes the fines, and the gas is cooled and either vented or recovered and recycled. The result is spherical to near-spherical powder with a low oxygen content, which is why gas atomization is the route used for additive manufacturing, metal injection moulding and thermal spray powders.
Gas atomization or water atomization, which route should I choose?
Choose by the powder the next process needs, not by cost alone. Inert gas atomization gives spherical particles, low oxygen content and a fine cut, which is what laser powder-bed printers, MIM feedstock and HIP capsules require. Water atomization gives irregular, higher-oxygen powder with excellent compressibility and green strength, at much higher throughput and a much lower cost per kilogram, which is what press-and-sinter structural parts, diamond tooling and friction materials require. The practical decision sequence is morphology and oxygen first, then the particle size cut, then throughput and cost. If your part is printed or moulded, the gas route is normally the answer; if it is pressed and sintered, the water route normally is.
What is the difference between VIGA and EIGA?
Both are inert-gas routes built for reactive and high-integrity alloys, and they differ in how the metal is melted. VIGA melts the charge in a crucible inside a vacuum induction furnace, refines the melt at low pressure to strip dissolved oxygen, nitrogen and hydrogen, back-fills the chamber with purified inert gas and then atomizes the melt, so it both cleans the metal and makes the powder; its practical limits are crucible contact and a longer cycle. EIGA has no crucible at all: the tip of a rotating or slowly descending pre-alloyed bar is melted by an annular induction coil and the droplets fall through a gas nozzle, so there is no ceramic contact and no refractory contamination path, which matters for titanium, titanium aluminide and other highly reactive alloys. VIGA is the usual answer for nickel and cobalt superalloys; EIGA is the usual answer for titanium and reactive alloys, provided a suitable electrode can be supplied.
Which metals can be atomized into powder?
Any alloy that can be melted and poured within the temperature the line is configured for, and that does not have to be protected from the atomizing medium at a cost the product cannot carry. In practice that covers iron, low-alloy, stainless and tool steels, maraging steel, nickel and cobalt superalloys, cobalt-chrome, copper, brass and bronze, aluminium alloys, titanium and titanium aluminide, nickel-titanium, precious metals including gold, silver, platinum and palladium and their brazing alloys, tin-based solders, neodymium-iron-boron and samarium-cobalt magnet alloys, tungsten-copper and molybdenum-copper composites, and developmental compositions such as high-entropy and amorphous alloys. The feed has to be metal first: ores, concentrates, slags, drosses, ashes and leach solutions are smelted or leached to metal before they can be atomized, not atomized directly.
What particle size can the line produce, and what does D50 mean?
D50 is the median particle size of the powder by volume: half of the powder by volume is finer than that figure and half is coarser. It is quoted together with D10 and D90, and with the span, which is D90 minus D10 divided by D50 and expresses how wide the distribution is. Working windows differ by process: roughly 15–45 µm for laser powder-bed fusion, 45–106 µm for electron beam powder-bed fusion, 45–150 µm for directed energy deposition, a D90 at or below about 22 µm for metal injection moulding, 45–106 µm for hot isostatic pressing, and sieve fractions from about 45 µm upward for press-and-sinter powder metallurgy. The line is configured around the window your process accepts, because the coarse tail of a distribution is a defect source even when the median looks correct.
Why does the oxygen content of the powder matter, and how is it kept low?
Oxygen in atomized powder sits mostly in the surface oxide, and oxide films disrupt melting, cause spatter and porosity in a printer, and reduce the sintered density and mechanical properties of a moulded or pressed part. Because specific surface area falls as 6 divided by the product of density and particle diameter, a fine powder carries far more surface per gram than a coarse one, so an oxygen figure is only meaningful when the particle size at which it was measured is stated. Keeping it low is a chain rather than a single feature: a leak-tight vacuum chamber with a verified pressure rise rate, purified inert gas with a low dew point, purging the chamber below about 100 ppm residual oxygen before melt-down on reactive alloys, a controlled cooling path in the tower, drying under inert gas rather than in air, inert powder transfer and packing, and on the water route a reduction anneal in hydrogen or a hydrogen-nitrogen mixture. The figure is then demonstrated by inert gas fusion analysis on every batch certificate.
Why is water atomized powder irregular, and what happens to it afterwards?
Water removes heat far more aggressively than gas, so water-atomized droplets freeze extremely quickly, often before surface tension has had time to pull them into spheres, and the particle surface oxide forms at the same time and locks in the irregular shape. The result is angular to rounded powder with a rough, oxide-covered surface and a high oxygen content, and it is exactly that roughness and irregularity that gives the powder its excellent compressibility and green strength in a press-and-sinter operation. Because of the surface oxide, water-atomized iron, steel and copper powders for structural use are normally dewatered, dried and then reduced in a hydrogen or hydrogen-nitrogen atmosphere to strip the oxide before sieving, blending and packing.
What causes satellite particles, and how are they reduced?
Satellites are small, already-solidified particles that weld onto larger, still-liquid droplets in the spray. They form when gas recirculation in the atomization chamber carries fines back up into the atomization zone: the high-velocity atomizing gas entrains gas from lower in the tower, setting up a recirculation loop that returns fine powder into the spray. Satellites are surface defects that reduce flowability and packing density and are rejected by additive manufacturing powder specifications. They are reduced structurally rather than chemically: a taller tower that gives droplets time to solidify before wall contact, a tower diameter matched to the spray cone, a close-coupled or free-fall nozzle chosen to suit the cut, and a controlled external gas stream introduced at the top of the tower to establish a downward flow that suppresses the upward transport of fines.
What determines the yield of usable powder, and what happens to the off-cut?
An atomization campaign produces a distribution rather than a single size, so the usable yield is the mass of the target cut divided by the charge mass, expressed as a percentage. It is set by the gas-to-metal ratio, the gas pressure and temperature, the melt delivery nozzle bore and the melt flow rate, the superheat, and the efficiency of the classification step that separates the cut from the rest. Published atomization data show that a one-unit increase in gas-to-metal ratio raises the usable yield of the target cut by roughly 6%, which is why gas consumption and yield are the same commercial question. What is not in the cut is not lost: oversize powder is normally returned to the melt and recycled, and the fines fraction is either sold into an application that can use it or handled as a separate recycle stream, with both fractions weighed and recorded as part of the campaign mass balance.
How is a batch of powder tested and certified?
Each batch and each classified fraction is sampled and tested before it is released. Particle size distribution is measured by laser diffraction, reported with sieve data, and stated as D10, D50, D90 and span. Oxygen is measured by inert gas fusion analysis and reported at the stated particle size. Apparent and tapped density, and flow rate by Hall or Carney funnel, cover the handling behaviour. Morphology, sphericity and satellite population are checked by scanning electron microscopy with image analysis. Chemistry is verified by spectrometry with combustion analysis for carbon and sulphur, moisture is checked gravimetrically, surface oxide and reduction state are assessed for water-atomized grades, and a contamination check is carried out where specified. A sealed retained sample is held with the batch record so a query can be answered months later.
Does atomization change the alloy composition or increase purity?
No. Atomization converts a melt into powder of that same melt: it does not remove impurities, it does not separate metal from slag, and it does not raise grade. If the charge enters the melt at 99.5% metal, the powder leaves at 99.5% metal, correctly converted into a free-flowing, classified and documented product. There are two real composition effects to plan for rather than assume away: elements with a low boiling point, such as zinc in brass or cadmium in some alloys, can be lost to fume during melting and atomization, which is why analysis is verified after the campaign; and reactive elements can oxidise if the atmosphere is not controlled. Grade is established upstream in smelting, hydrometallurgy, refining and electrolysis, and the atomizer is judged on how faithfully it carries that composition into the powder.
Can the line produce powder for both 3D printing and metal injection moulding?
Yes, and the two requirements pull in different directions, so the line is configured for the one you are actually selling. Additive manufacturing wants a spherical powder with a controlled distribution in the machine’s window, a low satellite count, good flow and a low oxygen content, and it tolerates a coarser median. Metal injection moulding wants a very fine powder, with a D90 at or below about 22 µm, a high tap density and a surface chemistry that the binder system can wet, because the powder has to fill a small mould and sinter to near-full density. A line configured for one can often be moved to the other by changing the nozzle, the classification set points and the atmosphere practice — which is the reason the atomizer, the tower and the classification section are specified as separately re-configurable modules.
Is metal powder production safe?
Fine metal powder is a combustible dust, and some powders, notably aluminium, titanium and rare-earth magnet alloys, are also pyrophoric when fine. The hazards are real and they are managed by design rather than by procedure alone: an inerted closed loop for collection, transfer, blending and packing; oxygen monitoring with purge and trip logic; bonding, grounding and conductive flooring to remove static discharge; temperature monitoring on the filter and the collection hopper; over-pressure and relief protection on the gas circuit; fire detection and suppression in the powder-handling section; and water-flow and water-temperature interlocks on the melting and cooling circuits. The safety case, the extraction system and the layout are specified with the line, and the local requirements on dust explosion, emissions and working atmosphere are asked for at the proposal stage, because they change the inerting level and the equipment selection.
What do you need from me to configure a powder atomization line?
The alloy with its target composition and tolerances; the target cut stated as D10, D50 and D90 with the span your process accepts; the oxygen ceiling of your powder specification at the particle size at which it is measured; morphology and flow requirements including sphericity, satellite limit, Hall or Carney flow and tapped density; the feed form as it will actually arrive, whether ingot, cathode, bar, electrode, clean scrap, returns, sponge or reduced powder; the campaign size in kilograms of melt and the number of campaigns per week or month; the annual or monthly tonnage of saleable powder by cut; and the site conditions, including electrical supply and transformer capacity, inert gas supply and whether gas recovery is wanted, cooling water, floor loading, the height available for the tower, and the local dust explosion and emission requirements. Where an answer is not yet fixed, we run a trial campaign rather than assume a value.
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