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:
Dec. 20, 2011
Naoya Hirase, Tokyo, JP;
Takanori Satou, Tokyo, JP;
Naoya Hirase, Tokyo, JP;
Takanori Satou, Tokyo, JP;
NIPPON STEEL & SUMITOMO METAL CORPORATION, Tokyo, JP;
Abstract
A continuously cast slab with a rectangular cross section, and made of high alloy containing Cr of 20 to 30 mass %, Ni of 30 to 50 mass %, and at least one of Mo and W as Mo+0.5W of 1.5 mass % or more is subjected to blooming and billet-making to yield a round bar having a diameter of 150 to 400 mm as a starting material of the seamless tube. The blooming and billet-making process is performed under a condition satisfying a relation of 1.3≦H/D≦1.8 where a short side length of the cross section of the cast slab is defined as H (mm), and the diameter of the round bar is defined as D (mm). The round bar is pierced-rolled to make a hollow blank; the hollow blank tube is elongation-rolled, and then diameter-adjusting-rolled to make the seamless tube, thereby preventing end cracking during piercing-rolling, and increasing yield.