The Effect of Prior Microstructure on the Hardness and Residual Stress Distribution in Induction Hardened Steels

Bars of 4140, 1045 and W1 steels have been induction hardened using two different cycles. Prior to hardening, the bars were annealed, developing three different starting microstructures. The microstructures have been characterized by scanning electron microscopy. Microhardness distribution has been measured, and the surface residual stresses have been determined using x-ray diffraction. The results are discussed in the context of the superhardness phenomenon.