Causes of distortion during high pressure gas quenching process of steel parts

Abstract

Quench hardening is a necessary process for improving the mechanical and fatigue performance of load bearing steel components, but liquid quenching can lead to large distortions. High pressure gas quenching is becoming a more popular choice, with the assumption that a slower cooling rate will lead to less distortion. While true for certain geometries, nonlinearities in distortion response can make understanding the dimensional change of a component difficult due to the inherently complex behavior during quenching. Through the use of modeling, and a specially designed coupon, the out-ofround distortion of an eccentric bore is examined for common high-pressure gas quenching conditions. The causes of distortion are examined and explained using the model, with insights into why the cooling rate has a nonlinear relation with distortion.