QUENCHED-TEMPERED HIGH-STRENGTH STEEL WITH YIELD STRENGTH OF 900 MPA TO 1000 MPA GRADE, AND MANUFACTURING METHOD THEREFOR

摘要

A quenched-tempered high-strength steel having a yield strength of 900-1000 MPa grade and a method of producing the same, with the components and amounts thereof by weight percentage being: C:0.16-0.20%, Si: 0.10-0.30%, Mn: 0.80-1.60%, Cr: 0.20-0.70%, Mo: 0.10-0.45%, Ni: 0.10-0.50%, Nb: 0.010-0.030%, Ti: 0.010-0.030%, V: 0.010-0.050%, B: 0.0005-0.0030%, Al: 0.02-0.06%, Ca: 0.001-0.004%, N: 0.002-0.005%, P≤0.020%, S≤0.010%, 0≤0.008%, and the balance of Fe and unavoidable impurities, and Ceq 0.51-0.60%, Ceq=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15; 3.7≤Ti/N≤7.0; 1.0≤Ca/S≤3.0; 0.8%≤Mo+0.8Ni+0.4Cr+6V≤1.3%. By using a process of controlling rolling, controlling cooling, and off-line quenching + tempering, a steel sheet produced according to the disclosure has a yield strength of 900-1080MPa, a tensile strength of 950-1200MPa, an elongation 10%, and an impact energy at - 40°C 40J.