Title:
PRODUCTION OF HIGH STRENGTH HOT BEND STEEL TUBE
Document Type and Number:
Japanese Patent JP3887832
Kind Code:
B2
Abstract:
PURPOSE: To produce a steel tube excellent in sour resistance and having strength and low temp. toughness, in the production of a large diameter welded steel tube, by specifying a base material, a welding wire, welding conditions, weld metal and the conditions of bending and the subsequent heat treatment.
CONSTITUTION: In a base material contg., by mass, 0.02 to 0.10% C, ≤0.5$ Si,, 0.5 to 2.0% Mn, ≤0.02% P, ≤0.02% S,≤0.05% Nb, ≤0.1-% Al, ≤0.4% Ni, ≤0.010% N, ≤0.0035% O, ≤0.05% Ti and/or 0.5% Mo, and the balance iron, the inside and outside faces are subjected to one pass submerged arc welding by low O flux and a low CTi-B welding wire and is thereafter subjected to bending and heat treatment. In this method, the weld metal has a compsn. contg. 0.02 to 0.10% C, ≤0.6% Si, ≤1. 60% Mn, ≤0.02% P, ≤0-02% S, ≤0.05% Nb, ≤0.02% Al, ≤0.4% Ni, ≤0.010% N and ≤0.035% O, and the balance iron and is welded to 0.07 to 0.21 Pcm. Next, it is heated to the Ac3 to 1100°C, is subjected to bending and is thereafter subjected to forced cooling to ≤300°C at a cooling rate of ≤50°C/sec, and the whole body of the tube is heated to 400 to 500°C for ≥10 min and is cooled at ≥0.03°C/sec.
Inventors:
Okabe Nochi
Koichi Yasuda
Shuichi Sakaguchi
Yamaguchi Tadamasa
Koichi Yasuda
Shuichi Sakaguchi
Yamaguchi Tadamasa
Application Number:
JP19044395A
Publication Date:
February 28, 2007
Filing Date:
July 26, 1995
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C21D8/10; C21D9/08; C21D9/50; C22C38/00; C22C38/16; C22C38/12; C22C38/14; (IPC1-7): C21D9/08; C21D8/10; C21D9/50; //C22C38/00; C22C38/16
Domestic Patent References:
| JP1044769B2 | ||||
| JP62107023A |
Attorney, Agent or Firm:
Eiichi Kobayashi