Crankshafts with hardened fillets between web and journals - and pins are roll-hardened after final turning

摘要

Parent patent described a process for mfg. a crankshaft for a piston motor, esp. a large diesel engine, with hardened transition zones between the journals and the webs, where initially the journals are machined oversize and the transition zones machined to finished dimensions, followed by local hardening of the transitions zones and then final turning of the soft journals to size, alignment and parallel tolerances. In the present invention after final turning, the surfaces of the journals are roll-hardened. Roll-hardening pref. starts at the end of the locally hardened zones, the journal includes the crank-pins. It is an economic method of increasing the stress-carrying ability of the crankshaft so that a higher engine performance can be obtd. without increasing the size of the crankshaft.