The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 13, 2019
Filed:
Jun. 29, 2016
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Yusaku Tomio, Nishinomiya, JP;
Hiroshi Kaido, Sodegaura, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
A stainless steel is provided having good corrosion resistance and good low-temperature toughness. A stainless steel contains, in mass %, Cr: 15.5 to 18.0%. The stainless steel has a matrix structure having, by volume ratio, 40 to 80% tempered martensite, 10 to 50% ferrite and 1 to 15% austenite. When a microstructure image obtained by photographing the matrix structure at a magnification of 100 times is positioned in an x-y coordinate system and each of 1024×1024 pixels is represented by a gray scale level, β defined by Equation (2) is not smaller than 1.55:1.0≤Mo+0.5W≤3.5  (1). Here, Mo and W are the Mo and W contents in mass %. In Equation (2), Su is defined by Equation (3), and Sv is defined by Equation (4): In Equations (3) and (4), F(u,v) is defined by Equation (5): In Equation (5), f(x,y) represents the gray level of the pixel at coordinates (x,y).