公开(公告)号：US20180312956A1

公开(公告)日：2018-11-01

申请号：US15769541

申请日：2016-10-19

Applicant: TOYOTA JIDOSHA KABUSHIKI KAISHA

Inventor： Kazuomi YAMANISHI ,  Hiroyuki INOUE ,  Yuji ADACHI ,  Takeshi USAMI

IPC: C23C8/22 ,  C22C38/26 ,  C22C38/22 ,  C22C38/06 ,  C22C38/04 ,  C22C38/02 ,  C22C38/00 ,  C21D8/02 ,  C21D6/00

CPC classification number: C23C8/22 ,  C21D1/06 ,  C21D1/74 ,  C21D1/773 ,  C21D6/002 ,  C21D6/005 ,  C21D6/008 ,  C21D7/13 ,  C21D8/0205 ,  C21D8/0226 ,  C21D8/0263 ,  C21D2211/004 ,  C21D2211/005 ,  C21D2211/009 ,  C22C38/001 ,  C22C38/002 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/12 ,  C22C38/22 ,  C22C38/26

Abstract: A method of producing a carburizing forging material includes heating a steel material at 1300° C. or higher, forming Nb in a solid solution state and then rolling the steel material, heating the rolled steel material in a range of 950 to 1050° C., hot forging the heated steel material in a range of 950 to 1040° C., precipitating a Nb carbonitride in the steel material by cooling the steel material or maintaining a temperature of the steel material under a condition in which a time spent in a range of 950 to 970° C. is 1 minute or longer, precipitating a ferrite phase in the steel material by cooling the steel material or maintaining a temperature of the steel material under a condition in which a time spent in a range of 730 to 870° C. is 10 minutes or longer, and cooling the steel material to room temperature.