| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a steel material such as a thick steel plate, a shape steel, a deformed bar steel, a bar steel and a steel wire having high strength and high ductility and having excellent energy absorption power, without adding expensive alloy elements and by using the existing production line without applying excessive loads onto production equipment, as the steel material used for structures such as buildings and bridges, automobile underbody steel materials and machine parts such as gears, and to provide a method for producing the steel material. <P>SOLUTION: The steel material comprises, by mass, 0.05 to 0.20% of C, 1.0 to 3.5% of Si, 4.5 to 5.5% of Mn, 0.001 to 0.080% of Al,≤0.030% of P,≤0.020% of S,≤0.010% of N and≤0.045% of Nb, and the balance Fe with inevitable impurities, and has a tensile strength of≥1,100 MPa and an elongation of≥25%, and the product between the tensile strength and elongation (TS×El) is≥30,000 MPa%. The steel material has a two phase structure in which the production ratio between ferrite and austenite is controlled by short time annealing treatment. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
