| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of producing steel for induction hardening having excellent cold workability in which crack sensitivity is reduced, and the occurrence of cracking on cold working is suppressed. SOLUTION: Steel having a composition containing, by mass, 0.35 to 0.70% C, 0.03 to 0.30% Si, 0.2 to 2.0% Mn and 0.01 to 0.05% Al, and the balance Fe with inevitable impurities is heated at a heating temperature of Ac<SB>3</SB>to 1,000°C, thereafter rolled or forged at a reduction of area of≥30%, further subjected to spheroidizing so as to be heated at Ac<SB>1</SB>to 790°C and to slowly be cooled at a rate of≤15°C/h in the temperature range of 730 to 700°C to control the spheroidization ratio after the spheroidizing to≥70%, and the depth of a decarburization layer to 0.1 to 0.5 mm. The steel is subjected to cold working at a working ratio of≥60%, and thereafter subjected to induction hardening, so that the steel for induction hardening having excellent cold workability is produced. COPYRIGHT: (C)2004,JPO
|
