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:
Dec. 24, 2019
Filed:
Feb. 18, 2016
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Hiroaki Kubota, Toyota, JP;
Masaaki Mizumura, Kisarazu, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
A metal pipe having a thickened end portion, the metal pipe includes: when viewed in a longitudinal direction of the metal pipe, a thin portion which has a thickness t; a first thickened portion which is provided on one end and has a thickness T which is larger than the thickness t; and a first taper portion which is provided between the thin portion and the first thickened portion and has the thickness which gradually increases from tto T; when a hardness of an inner surface of the first thickened portion is measured in a circumferential direction and the hardness is plotted with respect to a position in the circumferential direction, in which a waveform representing a high hardness portion having a hardness which is 95% or more of a maximum hardness in the circumferential direction and a waveform representing a low hardness portion having a hardness which is less than 95% of the maximum hardness alternately appear, and a plurality of combinations of the waveform representing the high hardness portion and the waveform representing the low hardness portion appear.