Investigation of the surface residual stresses in spray cooled induction hardened gearwheels

The objective of the current investigation consists of testing the interchangeability of polymer solutions used during induction hardening with water – air spraying regarding compressive residual stresses. Gearwheels made of 42CrMo4 steel were induction hardened and subsequently quenched using water – air spray cooling. The effect of different cooling parameters on the surface’s residual stresses in the gearwheel’s tooth flanks was analyzed by means of X-ray diffraction. The microstructure was characterized by means of hardness measurements and light-microscopy. Residual stresses could be specified after using water – air spray cooling and are comparable to those using polymer quenching. Quench parameters leading to maximum compressive residual stresses in tooth flanks were determined.