Yield strength 800 MPa class high toughness hot rolled high strength steel and method for producing the same

摘要

In terms of weight percentage, C: 0.02 to 0.05%, Si ≦ 0.5%, Mn: 1.5 to 2.5%, P ≦ 0.015%, S ≦ 0.005%, Al: 0.02 to 0.10%, N ≦ 0.006%, Nb: 0.01 to 0.05%, Ti: 0.01-0.03%, 0.03 ≦ Nb + Ti ≦ 0.06%, Cr: 0.1-0.5%, Mo: 0.1-0.5%, B: 0.0005-0.0025%, the balance being Fe and unavoidable impurities 800 MPa class A high toughness hot-rolled high-strength steel and a method for producing the same. The ultra-low carbon martensite structure was obtained by direct quenching, the yield strength reached 800MPa class, and the -80 ℃ impact energy reached 100J or more.