Title:
METHOD FOR MANUFACTURING OVAL SEAMLESS STEEL TUBE
Document Type and Number:
WIPO Patent Application WO/2021/026716
Kind Code:
A1
Abstract:
Disclosed is a method for manufacturing an oval seamless steel tube. The method comprises the procedures of intermediate-product cold working, final cold-drawing, heat treatment for a finished product, and a straightening treatment, wherein the procedure of intermediate-product cold working involves cold rolling machining being performed on a circular tube pierced billet, and the ratio of an outer diameter D0 of a final cold-rolled circular tube to a diameter D1, in a long axis direction, of an oval tube is controlled to be 1.10-1.50; the procedure of final cold-drawing uses empty sinking or cold-drawing with a core diameter to cold-draw an intermediate circular tube into the oval tube, wherein the cold-drawing speed is 1.0-10.0 m/min; and black annealing or bright annealing is adopted for heat treatment for the finished product, wherein the annealing temperature is 1050-1100ºC, the heat preservation time is determined according to the wall thickness WT1 of the oval tube, and the heat preservation time is (1.0-3.0)*WT1 min/mm.
Inventors:
CAI ZHIGANG (CN)
SU CHENG (CN)
YANG CHEN (CN)
WANG TAO (CN)
LYU YUE (CN)
LUO XIA (CN)
SU CHENG (CN)
YANG CHEN (CN)
WANG TAO (CN)
LYU YUE (CN)
LUO XIA (CN)
Application Number:
PCT/CN2019/100169
Publication Date:
February 18, 2021
Filing Date:
August 12, 2019
Export Citation:
Assignee:
ZHEJIANG JIULI HI TECH METALS (CN)
International Classes:
B21C37/06
Foreign References:
| CN102615140A | 2012-08-01 | |||
| CN101249522A | 2008-08-27 | |||
| CN103170522A | 2013-06-26 | |||
| CN102836895A | 2012-12-26 | |||
| JPS60124415A | 1985-07-03 |
Attorney, Agent or Firm:
ZHEJIANG KG IP LAW FIRM (CN)
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