Invention Grant
- Patent Title: Martensitic stainless steel products
- Patent Title (中): 马氏体不锈钢制品
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Application No.: US09453714Application Date: 1999-12-03
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Publication No.: US06440234B1Publication Date: 2002-08-27
- Inventor: Hisashi Amaya , Toshiro Anraku , Yasuyoshi Hidaka
- Applicant: Hisashi Amaya , Toshiro Anraku , Yasuyoshi Hidaka
- Priority: JP10-348187 19981208; JP11-231382 19990818
- Main IPC: C22C3818
- IPC: C22C3818

Abstract:
A martensitic stainless steel product having a chromium content of 9 to 15% by weight and a surface from which mill scales generated during production are removed by a shot blasting. The surface satisfies that, when a color image of the surface taken with 640×480 pixels is analyzed on blue color and a histogram of the pixel numbers and the tones divided into 0 to 255 classes is obtained, a relationship between the maximum frequency Yp and the tone value Xp at which Yp is counted satisfies an inequality, 800Xp−Yp−27000>0. This steel product is superior in weatherability under atmospheric environments, and also superior in sulfide stress cracking resistance under environments containing hydro-sulfide.
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