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. 21, 2021
Filed:
Sep. 21, 2016
Baoshan Iron & Steel Co., Ltd., Shanghai, CN;
BAOSHAN IRON & STEEL CO., LTD., Shanghai, CN;
Abstract
A method for manufacturing a bainite high-strength seamless steel tube, comprising the following steps: smelting, manufacturing a billet, heating, perforating, rolling, stretch reducing or sizing to obtain tube, and cooling. In the cooling step, the quenching starting temperature is controlled to be at least 20° C. higher than the Ar3 temperature of the steel grade; the finish cooling temperature is controlled to be within a range between T1 and T2, where T1=519-423 C-30.4Mn, T2=780-270 C-90Mn, and the units of the T1 and the T2 are ° C.; in the formulas, C and Mn respectively represent the mass percents of element C and element Mn of the steel grade, the content of the element C is 0.06-0.2%, and the content of the element Mn is 1-2.5%; the cooling rate is controlled to be 15-80° C./s; and the finished product of the bainite high-strength seamless steel tube is directly obtained after the cooling step. The manufacturing of a bainite high-strength seamless steel tube using the method requires neither the addition of precious alloying elements nor the subsequent heat treatment. Therefore the production costs are low.