Distortions of Comparatively Small-Sized Gears Caused by Induction Hardening : 1st Report, Mainly on Thermal Distortions

Abstract

It is usually accepted that steel parts surface hardened by induction heating generally exhibitless total distortion. However, the induction hardening of small-sized gears is a matter of recent years and we have as yet very little information on the results concerning the systematic measurements of the distortions of them. In this investigation spur gears of 10 diametral pitch, were induction hardened with various heating conditions, and distortions, generated by thermal changes as well as by quenching transformations, were measured in detail. In the 1st report, the results of measurements of distortions, caused by thermal changes only, were described. Materials of gears were pure iron. Items of measurements were as follows : outer diameter, inner diameter, width, whole depth, radius or root circle, thickness of tooth, undulation of tooth trace. and tooth profile.