Influence of Hardenability on Gear Distortions Caused by Hardening

Abstract

The kinds of materials have different effects on gear distortions caused by hardening, even if heat-treatments of the raw material and gear are the same. In this experiment, the test gears which were made of steel materials containing different amounts of some chemical compositions in two kinds of steel were case-hardened. And from the measurements of gear distortions, namely, change of tip cylinder diameter and of face width, it became clear that there exists a relationship between ideal critical diameter of the test material, and the gear distortions. Also grain sizes were changed through annealing process. Originally the hardenability is a criterion for the thickness of hardened layer. It is confirmed from this experiment that the hardenability is related with gear distortions caused by hardening.