Invention Grant
- Patent Title: Method for manufacturing martensitic stainless steel pipe or tube
- Patent Title (中): 制造马氏体不锈钢管或管的方法
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Application No.: US12593677Application Date: 2008-03-26
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Publication No.: US08168014B2Publication Date: 2012-05-01
- Inventor: Nobuyuki Mori
- Applicant: Nobuyuki Mori
- Applicant Address: JP Osaka
- Assignee: Sumitomo Metal Industries, Ltd.
- Current Assignee: Sumitomo Metal Industries, Ltd.
- Current Assignee Address: JP Osaka
- Agency: Clark & Brody
- Priority: JP2007-092397 20070330
- International Application: PCT/JP2008/055644 WO 20080326
- International Announcement: WO2008/123275 WO 20081016
- Main IPC: C21D9/08
- IPC: C21D9/08

Abstract:
The method for manufacturing a martensitic stainless pipe includes heating the steel pipe until the external surface temperature thereof reaches a predetermined temperature not lower than A3 transformation point+20° C. and not higher than 980° C. The heated steel pipe is first water cooled until the external surface temperature thereof reaches a predetermined temperature not lower than 350° C. The water cooled steel pipe is air cooled until the external surface temperature thereof reaches a predetermined temperature not higher than 250° C. The air cooled steel pipe is either water or air cooled until the external surface temperature thereof reaches normal temperature. The cooling rate of the steel pipe in the first cooling step is determined according to the wall thickness of the steel pipe so that the amount of heat recuperation for the external surface temperature of the steel pipe in the second cooling step is not higher than 50° C.
Public/Granted literature
- US20100193086A1 METHOD FOR MANUFACTURING MARTENSITIC STAINLESS STEEL PIPE OR TUBE Public/Granted day:2010-08-05
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