TREATING METHOD OF BILLET FOR COLD-FORGING AND CONTINUOUS COLD FORGING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a treating method of a billet, capable of cold forging a crank shaft, and the like, continuously without executing a process of an intermediate softening treatment. ;SOLUTION: A blank 2 taken out from a heating furnace 1 is rapidly cooled after rolling to make the surface layer a fine martensitic structure, and successively, the blank 2 is annealed to change the martenstic structure into a fine spheroidal structure composed of ferrite and cementite.;COPYRIGHT: (C)2001,JPO