The mechanical properties of PM parts have been improved, with an increased strength comparable to that of wrought low alloy steels. The fatigue strength of PM steels, however, are only half of that of wrought low alloy steels. Accordingly improvement of the fatigue strength is necessary to expand the applications.
A new PM steel was developed by using a double-press double-sintering process. It exhibits a tensile strength of 1560MPa, a fatigue strength of 470MPa, shows three times better wear resistance and five times improved machinability compared with conventional high strength PM steels.