PROCESSING OF A HIGH-ALLOY HIGH-SPEED STEEL VIA WATER ATOMIZATION ANDDIRECT SINTERING

The common powder metallurgical production route for high-alloy high-s peed steels is based on gas-atomised powder, subsequently encapsulated and hot isostatically pressed at temperatures near 1150-degrees-C. Th e billets are further rolled into bars or rods. The microstructures of these materials show very fine carbide distributions which yield high fracture strength values. This paper presents the results of a study of the processing of one such alloy (in wt-%: 2C-4Cr-12W-10Mo-4.5V-12C o, bal, Fe) by means of an alternative near net shape P/M route, using vacuum sintering of die compacted water atomised powder. After heat t reatment, this particular steel, produced by this more economical rout e, has fracture strength values of approximately 1900 MPa, at a hardne ss of above 1000 HV30, compared with 2750 MPa for commercial HIPped ma terial of similar composition.