Hardening process for crankshafts

摘要

A hardening process for a crankshaft which includes subjecting the crankshaft to a first induction hardening process to produce a hardened layer of a substantial thickness at all bearing locations and at all transitional points between the crank pins, journal pins and crank webs. Subsequently tempering the hardened zones of the crankshaft at the transitional points to a hardness value permitting a subsequent alignment of the crankshaft. Subjecting the crankshaft to a further induction hardening process to provide a second hardened layer only at the bearing locations which second layer has a depth which is less than the depth of the first hardened layer. The thus processed crankshaft is then subject to an expansion process to eliminate internal stresses therein.