Method for reducing the hardening distortion during case hardening of large toothed rims formed of steel and support body members suitable for such purpose

摘要

To reduce the hardening distortion during the case hardening of large toothed rims or gear wheels formed of steel the toothed rim or the like during cooling thereof, starting from the hardening temperature, is shrunk during the gamma / alpha transformation of its core material upon a support body member, and then there is limited, during the further cooling to room temperature, the increase of the stresses in the toothed rim in that the support body member is inserted into the toothed rim in a pre-heated condition. The material of the support body member has a greater coefficient of thermal expansion than that of the toothed rim.