Invention Grant
- Patent Title: Method of making quenched and tempered steel pipe with high fatigue life
- Patent Title (中): 淬火回火钢管疲劳寿命长的方法
-
Application No.: US14222973Application Date: 2014-03-24
-
Publication No.: US09540704B2Publication Date: 2017-01-10
- Inventor: Masaru Fujihara , Tsunetoshi Suzaki
- Applicant: NISSHIN STEEL CO., LTD.
- Applicant Address: JP Tokyo
- Assignee: NISSHIN STEEL CO., LTD.
- Current Assignee: NISSHIN STEEL CO., LTD.
- Current Assignee Address: JP Tokyo
- Agency: Clark & Brody
- Main IPC: C21D9/08
- IPC: C21D9/08 ; C21D8/10 ; C21D1/18 ; C22C38/26 ; C22C38/28

Abstract:
A method for producing a high fatigue life quenched/tempered steel pipe comprises a quenching treatment of keeping an unquenched starting steel pipe having a composition that comprises, % by mass, C: 0.1 to 0.4%, Si: 0.5 to 1.5%, Mn: 0.3 to 2%, P: at most 0.02%, S: at most 0.01%, Cr: 0.1 to 2%, Ti: 0.01 to 0.1%, Nb: 0.01 to 0.1%, Al: at most 0.1%, B: 0.0005 to 0.01%, and N: at most 0.01%, with a balance of Fe and inevitable impurities, at 900 to 1100° C. for 10 to 60 seconds and then rapidly cooling it. The cooled pipe is subjected to a tempering treatment of keeping the pipe at 280 to 380° C. for 10 to 60 minutes.
Public/Granted literature
- US20140202600A1 METHOD OF MAKING QUENCHED AND TEMPERED STEEL PIPE WITH HIGH FATIGUE LIFE Public/Granted day:2014-07-24
Information query