Abstract
Recent improvement in Diesel engine techniques has always been demanding the high quality crankshaft with higher strength and service reliability.
The first part of this paper deals with the improvement of fatigue limit and reliability of both solid type crankshafts made of C-steel and Cr-Mo higher tensile strength steel associated with continuous grain flow forging (RR crankshafts) . After then, it describes the strengthening effects of fillets cold rolling for a Cr-Mo higher tensile strength steel crankshaft.
The second part deals with the relationships between hardening features and operational conditions of fillets cold rolling. It describes the hardening features are mainly influenced by the two factors of the roll pushing force and yield point of material, and scarcely affected by other operational conditions.
In connection with this, it suggests that as an assurance measures of fillets cold rolling, the roll contact width after the treatment and the hardness increase of fillets on completion of crankshafts will be preferable.
