Powder metallurgy
Powder metallurgy (PM) is a manufacturing process where metal powder is compacted and then hot pressed or sintered. This results in a very uniform microstructure with finely dispersed carbides—without the segregation found in conventionally melted steel.
What Is Powder Metallurgy
In powder metallurgy (PM), the steel is not melted and cast as a liquid but built up from fine metal powder. The powder is first compacted and then consolidated under pressure and heat — for example by hot isostatic pressing (HIP) or sintering.
The Advantage
In conventional melting, segregation occurs: alloying elements and carbides distribute unevenly because they migrate during slow solidification. With the PM process, each powder grain solidifies almost instantly. The result is a fine, uniform microstructure with very finely distributed carbides — which is why PM steels at the same hardness are often tougher and more consistent in behavior.
Typical Grades
Well-known are PM high-speed steels (PM M4, PM T15, ASP grades) and PM cold-work steels (CPM 3V, CPM 10V, Vanadis). They are used in stamping tools, milling cutters, plastic molds, and knives, where the combination of hardness and toughness matters.
Welding PM Steels
When welding, a PM steel behaves basically like a highly alloyed tool steel: preheat, work with a filler matched to the microstructure, and temper immediately after welding. However, the PM structure in the heat-affected zone coarsens again — the special fine grain is lost there.