Title:
WIDE-FLANGE SHAPE STEEL FOR TUNNEL TIMBERING, AND ITS PRODUCTION
Document Type and Number:
Japanese Patent JP3863647
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To improve weld crack resistance, to minimize hydrogen-induced defects, and to improve toughness by specifying a composition consisting of C, Si, Mn, Al, Ti, Nb, Mo, V, and Fe, controlling the amounts of S, P, H, and N as impurities, and further specifying thickness and tensile strength, respective ly.
SOLUTION: A steel, having a composition which consists of, by weight, 0.08-0.17% C, 0.05-0.20% Si, 0.9-1.8% Mn, 0.005-0.10% Al, 0.005-0.05% Ti, 0.02-0.07% Nb, either or both of 0.1-0.5% Mo and 0.01-0.1% V, and the balance Fe with inevitable impurities and further contains, if necessary, prescribed amounts of Cu, Ni, Cr, Co, W, B, Rem, Ca, and Mg and in which the amounts of S, P, H, and N as impurities are limited to ≤0.010%, ≤0.020%, ≤2.5 ppm, and >50-120 ppm, respectively, is used. This steel is rolled at ≥1250°C heating temp. and ≥900°C finishing temp. into a wide flange shape of 6-25 mm thickness and then air cooled. By this method, the wide-flange shape steel for tunnel timbering, containing ≥60% bainite and having (590 to 780) N/mm2 tensile strength, can be obtained.
Inventors:
Atsuhiko Yoshie
Yoshiyuki Watanabe
Aimoto Virtue
Yoshiyuki Watanabe
Aimoto Virtue
Application Number:
JP29253197A
Publication Date:
December 27, 2006
Filing Date:
October 24, 1997
Export Citation:
Assignee:
Nippon Steel Corporation
International Classes:
C22C38/00; E21D11/18; B21B3/00; C21D9/00; C22C38/14; (IPC1-7): C22C38/00; B21B3/00; C21D9/00; C22C38/14; E21D11/18
Domestic Patent References:
| JP10195603A | ||||
| JP10152751A | ||||
| JP6057371A |
Attorney, Agent or Firm:
Hiroaki Tamura
Tomoyuki Yabuki
Tomoyuki Yabuki