Material for making and heat treating crankshafts for high-speed diesel engines

Conclusions

• 1. The use of high-alloy 18KhNVA steel for manufacturing crankshafts is not advisable:

• a) the high sensitivity of high-strength steel to stress concentration means frequent fatigue rupture during operation;

• b) reduction in the strength of the shaft metal through increase in residual austenite cannot be recommended since it involves a reduction in the stability of the shaft (heating during grinding or cooling below 0° may cause the austenite to change into martensite and warp the shaft).

• 2. The manufacture of engine crankshafts from loweralloyed steels would bring about a considerable saving in alloying elements and improve the machinability of the parts. A sorbite structure is best for parts working under cyclic stress.