Thermal and thermomechanical treatment of P/M constructional steels — A survey

Abstract

The thermal and thermomechanical treatment of P/M steels has a number of distinguishing features linked with their porosity: Heating for quenching must be performed in a protective atmosphere; the thermal conductivity and hence hardenability of P/M steels are less than those of rolled steels; consequently, it is necessary to intensify the cooling of these steels in quenching. Apart from this, the presence of numerous macro- and microdefects in P/M steels results in a shift of critical points in the heating and cooling of these steels. The thermomechanical treatment of P/M steels must be performed with larger reductions compared with rolled steels in order to attain maximum density in the porous sintered blanks used.