公开(公告)号：EP1681359A4

公开(公告)日：2009-03-11

申请号：EP04772713

申请日：2004-08-27

Applicant: NAT INST FOR MATERIALS SCIENCE

Inventor： OHBA TOSHIO ,  SAWADA KOTA ,  KIMURA KAZUHIRO ,  OKADA HIROKAZU ,  ABE FUJIO

IPC: C21D9/00 ,  C21D1/18 ,  C21D1/28 ,  C21D6/00 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/18 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/30 ,  C22C38/32 ,  C22C38/54 ,  F01D25/24 ,  F02C7/00

CPC classification number: C22C38/02 ,  C21D1/18 ,  C21D1/28 ,  C21D6/002 ,  C21D9/0093 ,  C22C38/04 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/30 ,  C22C38/32 ,  F01D25/243

Abstract: A high temperature bolt material, characterized in that it is a ferrite steel comprising 8 wt % or more of Cr and having a tempered martensite structure and can be used in a high temperature region of higher than 500°C; and a method for producing the high temperature bolt material which comprises subjecting the above-mentioned steel material to a heat treatment comprising a quenching or normalizing at a temperature of 1000°C or higher and then to a tempering at a temperature of 730°C or higher. The above ferrite steel high temperature bolt material is excellent in characteristics of the resistance to stress relaxation.