Title:
ULTRAHIGH STRENGTH STEEL PLATE EXCELLENT IN DELAYED FRACTURE RESISTANCE AND ITS PRODUCTION
Document Type and Number:
Japanese Patent JP3514276
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a high strength steel plate, having excellent delayed fracture resistance even in the case where the infiltration of hydrogen in the amount of about 10ppm takes place.
SOLUTION: This steel plate has a component system which consists of 0.08-0.18% C, ≤1% Si, 1.2-1.8% Mn, ≤0.03% (including 0%) P, ≤0.01% S, 0.01-0.1% sol.Al, ≤0.005% N, ≤0.005% 0,5-25ppm B, further one or ≤2 kinds among 0.005-0.04% Nb, 0.005-0.04% Ti, and 0.005-0.04% Zr, and the balance essentially Fe with inevitable impurities and in which Ceq, represented by Ceq= C+Si/24+Mn/6, and tensile strength TS satisfy TS(MPa)≥2270×Ceq+260 and Ceq≤0.5, respectively. Further, this steel plate has a structure constituted of ≥80vol.% martensitic phase.
Inventors:
Nagataki, Yasunobu
Hosoya, Yoshihiro
Hosoya, Yoshihiro
Application Number:
JP27139095A
Publication Date:
March 31, 2004
Filing Date:
October 19, 1995
Export Citation:
Assignee:
NKK CORP
International Classes:
C21D8/02; C21D9/52; C22C38/00; C22C38/14; (IPC1-7): C22C38/00; C21D8/02; C21D9/52; C22C38/14
Attorney, Agent or Firm:
細江 利昭