Patent ID: 11905992
Assignee: GM GLOBAL TECHNOLOGY OPERATIONS LLC
Field: Materials, metallurgy (Chemistry)
Classification: CPC F  C  Y | IPC C  F

Claim 14:
15. A crankshaft for an internal combustion engine, the crankshaft comprising:
a main journal having a surface and a hardened case, wherein the hardened case penetrates into the main journal from the surface to a depth, wherein the main journal is comprised of steel having between 0.3 wt % and 0.77 wt % Carbon, and wherein the surface of the main journal has been heated to an intercritical temperature of between 724° C. and 822° C. and the surface of the main journal has been cooled such that the hardened case has a microstructure comprising between 15 wt % and 30 wt % ferrite with the balance of martensite.