Experimental and Simulation Studies On Asymmetrical Quench Distortion of Long Thin Steel Parts

　　　　This report focused on asymmetrical quench distortion (bending and warping) of steel parts. Bending or warping in quenching is often observed for long thin steel parts. Asymmetrical shape of a steel part increases the degree of asymmetrical distortion. In the other hand, nonuniform heat transfer coefficient (HTC) on the steel part also increases it. The sharp edges of steel parts results in the premature collapse of vapor blanket on the quenched part, and as the result, increase the nonuniformity of HTC and the asymmetrical distortion. 　　　　Quench simulation result showed that the bending or warping of long thin steel parts is mainly resulted from longitudinal strain of supercooled austenite in high temperature cooling phase, and the warping is controlled by the longitudinal strain in quenching. The result also shows that the longitudinal strain largely depends on nonuniformity of cooling of steel part. These analyses clarified the mechanism of warping distortion during quenching of long thin parts.