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:
Oct. 18, 2016
Filed:
Feb. 14, 2012
Toshio Mochizuki, Tokyo, JP;
Toshio Mochizuki, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
The pipe end correction method for correcting an inner diameter of pipe end of a seamless pipe made of a high Cr stainless steel containing 8 to 35 mass % Cr, and 0.1 to 10 mass % Ni includes a pipe end correction step following hot tube-making and heat treatment, that forces a plug into the inside of pipe end portion for inner diameter correction so as to expand the pipe end portion while oxide scale, which is generated during tube-making or heat treatment, remains accumulated on an inner surface of the pipe end portion. A lubricant film forming step, prior to the pipe end correction step, applies lubricant at least either on the inner surface of the pipe end portion of the seamless pipe or on a surface of the plug. Seizure flaws can be prevented on the inner surface of the pipe end portion of the high Cr stainless steel.