On the Study of Distortions in Steel Plate Specimens Carburized on a Single Side and Oil Quenched

摘要

Carburizing-quenching processes have been used for adding the fatigue strength and wear resistance effectively to machine parts. However, efforts for reducing the quench distortions induced from the processes, which are not avoidable, have been repeated over many years. The heat treatment simulation has been used as a tool to solve the problems by predicting quench distortions and residual stresses after the processes. Moreover, the generating mechanism of phenomena during the processes has been explained using simulated results. To enhance the simulation requires improving models and collecting characteristic data for the simulation by repeating comparisons with experiments. Quench bending in steel plate specimens carburized on a single side and oil quenched was measured for verifying simulation models, although it is a specific experimental condition for the purpose. Bending behaviors showed clearly that an expansion of crystal lattice in steels are induced by diffused carbon atoms during the carburizing processes, which should be considered for predicting the final bending shape accurately. In this study, carburizing-quenching tests of several steel plate and disk specimens were performed by repeating and complementing some reviewed examples in literature. Some previous results were confirmed and new findings were derived, especially a quench distortion in disks is transferred from an axisymmetric dishing to a simple bending, when its thickness decreasing to a limit.