Iron and steel powders are fine metal particles that are pressed and sintered into near-net-shape parts, injection moulded, or melted layer by layer in additive manufacturing. Powder metallurgy (PM) makes gears, bushes, bearings and structural parts with little or no machining, and is used above all in the automotive industry.
Also called
Iron powder
Steel powder
Atomised powder
Sponge iron powder
PM powder
Sintered parts
MIM powder
AM powder
3D printing powder
AR
مساحيق معدنية (مسحوق الحديد والفولاذ)
ZH
金属粉末（铁粉、钢粉）
DE
Metallpulver (Eisen- und Stahlpulver)
FR
Poudres métalliques (poudre de fer et d'acier)
ES
Polvo metálico (polvo de hierro y acero)
IT
Polveri metalliche (polvere di ferro e acciaio)
TR
Metal tozu (demir ve çelik tozu)
RU
Металлические порошки (железный и стальной порошок)
Main formsWater-atomised iron and steel powder, sponge (reduced) iron powder, gas-atomised alloy powder, pre-alloyed and diffusion-alloyed powders, premixes
Typical sizesPress-and-sinter powders mostly below 150–200 µm; MIM below about 20 µm; AM typically 15–63 µm
Main standardsMPIF Standard 35, ISO 5755, ISO 4497, ISO 4490, ISO 3923-1, ISO/ASTM 52900
Typical usesAutomotive gears, bushes, sprockets and structural parts; self-lubricating bearings; filters; welding electrode coatings; magnetic cores; 3D printing
Overview
Most iron and steel powder is made by water atomisation: a stream of molten steel is broken up by high-pressure water jets into irregular particles, which are then dried and annealed in hydrogen to soften them and lower their oxygen. Sponge iron powder is made by reducing iron ore or mill scale in the solid state and milling the porous product. Gas atomisation, with nitrogen or argon jets, gives clean spherical particles for metal injection moulding (MIM) and additive manufacturing.
In press-and-sinter PM the powder, mixed with graphite, copper or nickel and a lubricant, is compacted in a die at high pressure and then sintered below its melting point, so the particles bond into a strong part that comes out of the furnace close to its final size. Because there is little waste and machining, PM is economical for large runs of complex small parts, and controlled porosity can be filled with oil to make self-lubricating bearings.
Powders are specified by chemistry, particle-size distribution, apparent density, flow rate and compressibility, all measured to ISO or ASTM test methods. The finished PM materials are designated by MPIF Standard 35 in North America and ISO 5755 internationally — for example FC-0208, an iron–copper–carbon steel.
World production of iron powder is concentrated in a few large makers in Europe, North America and Asia. The GCC has little PM part production and imports powders mainly for welding consumables, thermal spraying, chemical uses and, increasingly, additive manufacturing in the oil and gas and aerospace sectors.
Forms & sizes
Water-atomised powder
Irregular particles with good compressibility; the main press-and-sinter grade
Sponge iron powder
Porous particles with good green strength; PM parts, welding electrode coatings, chemicals
Pre-alloyed and diffusion-alloyed
Mo, Ni, Cu or Cr alloyed into or bonded onto iron particles for high-strength PM steels
Gas-atomised powder
Spherical particles for metal injection moulding, hot isostatic pressing and additive manufacturing
Premixes
Ready-to-press mixes of iron powder, graphite, copper and lubricant
Standards & grades
Region
Standard
What it covers
USA
MPIF Standard 35
Materials standards for powder metallurgy parts — PM structural parts, MIM and bearing materials, with designations such as FC-0208
