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:
Jun. 24, 2013
Filed:
Jul. 01, 2008
Chihiro Hayashi, Sendai, JP;
Chihiro Hayashi, Sendai, JP;
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Abstract
A method for manufacturing a seamless pipe, capable of preventing the carburization phenomenon that occurs in a manufacturing process of pipe and simplifying an elongation rolling process, is provided. In this method, after piercing in the piercing rolling process, rolling is performed without using an inside regulating tool in the elongation rolling process, or without performing the elongation rolling followed by reducing rolling in a reducing rolling process, andthickeningreducing the wall thicknessis then performed by use of a cold mill or cold draw bench in a cold rolling process. According to this method, the trap of graphite fine particles in the inner and outer surfaces of the pipe that took place in the conventional elongation rolling process can be minimized to prevent the carburization of the pipe. The method of the present invention is effective, particularly as a measure for preventing the carburization of an ultra-low carbon stainless steel or high alloy steel.