Title:
HIGH STRENGTH STEEL AND ITS PRODUCTION METHOD
Document Type and Number:
Japanese Patent JP3888333
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a high strength steel having a tensile strength of ≥480 MPa and having excellent workability and excellent notch fatigue resistance.
SOLUTION: The high strength steel has a chemical composition consisting of 0.01 to 0.20% C, 0.01 to 2.5% Si, 0.05 to 3.5% Mn, 0.005 to 0.15% P, 0.003 to 0.04% S, 0.001 to 2.5% Al, 0.01 to 0.20% Ti and 0.0004 to 0.0150% N, and the balance Fe with impurities, and contains inclusions with a particle diameter of ≥0.3 μm per in an amount of 50 to 50,000 pieces per cross-sectional area of mm2, wherein the mean particle diameter of the inclusions is ≤7 μm. The high strength steel may comprise one or more groups selected from the (a) to (d) groups: (a) one or more kinds of metals selected from ≤0.1% Nb and ≤0.2% V; (b) one or more kinds of metals selected from ≤1.0% Mo, ≤1.0% Ni and ≤1.0% Cu; (c) one or more kinds of metals selected from ≤1.0% Cr and 0.0005 to 0.003% B; and (d) one or more kinds of metals selected from 0.0002 to 0.01% Ca, 0.0002 to 0.01% Mg and 0.0002 to 0.01% rare earth metals.
Inventors:
Yuku Kikuchi
Yoshiaki Nakazawa
Yoshiaki Nakazawa
Application Number:
JP2003168957A
Publication Date:
February 28, 2007
Filing Date:
June 13, 2003
Export Citation:
Assignee:
SUMITOMO METAL INDUSTRIES,LTD.
International Classes:
B21B1/26; C22C38/00; B21B3/00; B22D11/00; B22D11/22; C21D9/46; C22C38/14; C22C38/58; (IPC1-7): C22C38/00; B21B1/26; B21B3/00; B22D11/00; B22D11/22; C21D9/46; C22C38/14; C22C38/58
Attorney, Agent or Firm:
Terutada Hogami
Mikiji Sugioka
Mikiji Sugioka
Previous Patent: HOT WATER HEATING TERMINAL DEVICE
Next Patent: PLANT STATE MONITORING METHOD AND PLANT MONITORING DEVICE
Next Patent: PLANT STATE MONITORING METHOD AND PLANT MONITORING DEVICE