The abrasion-resisting steels are used for structural parts and required for construction machinery parts. Generally, they are so difficult to form the desirable product shape that they must be subjected to a kind of softening heat treatment. In the past, the full annealing treatment with a very extended period of 24 h has been conducted in our production, however, the spheroidizing heat treatment brings about a good machinability with a brief heat treatment time.1) In this study, it is investigated that the effect of the spheroidizing annealing on mechanical properties and microstructure. As a result, we could shorten the heat treatment time and obtain comparable properties to the conventional products by adopting spheroidizing annealing. It was found that, in the proeutectoid ferrite, it is effective to austenitize before spheroidizing period to decrease the yield stress because of coarsening pearlite colony size and spreading the pearlite lamellar spacing.
