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:
Mar. 30, 2010
Filed:
Jan. 07, 2005
Shigeru Kidani, Kainan, JP;
Mutsumi Tanida, Wakayama, JP;
Shigeru Kidani, Kainan, JP;
Mutsumi Tanida, Wakayama, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
The present invention provides a martensitic stainless steel seamless pipe and a method of making, wherein the pipe has minimal inner surface defects and prevents delayed fracture generation in the impact-worked portions. The pipe comprises C: 0.15 to 0.22%, Si: 0.1 to 1.0%, Mn: 0.10 to 1.00%, Cr: 12.00 to 14.00%, P: 0.020% or less, S: 0.010% or less, N: 0.05% or less, O(Oxygen): 0.0060% or less, at least one alloying element selected from V, Nb and Ti of 0.005 to 0.200% and B of 0.0005 to 0.0100%, and the balance Fe and impurities, wherein either the following inequalities (1), (2), (4) and (5) or the following inequalities (1), (3), (4) and (5) are satisfied:C*+10N*≦0.45,  (1)H1≦−0.003(C*+10N*)+0.0016,  (2)H2≦−0.0018(C*+10N*)+0.00096,  (3)Cr*≦9.0,  (4)S≦0.088N*+0.00056,  (5).