Abstract: The present invention provides an abrasion resistant steel having a hardness of HB400 to HB520, having little change of hardness during long term use, and superior in toughness, characterized by containing, by mass %, C: 0.21% to 0.30%, Si: 0.30 to 1.00%, Mn: 0.32 to 0.70%, P: 0.02% or less, S: 0.01% or less, Cr: 0.1 to 2.0%, Mo: 0.1 to 1.0%, B: 0.0003 to 0.0030%, Al: 0.01 to 0.1%, and N: 0.01% or less, further containing one or more of V: 0.01 to 0.1%, Nb: 0.005 to 0.05%, Ti: 0.005 to 0.03%, Ca: 0.0005 to 0.05%, Mg: 0.0005 to 0.05%, and REM: 0.001 to 0.

Abstract: A process for producing steel possessing a high level of toughness and strength free of anisotropy and having good resistance to stress corrosion cracking in seawater conditions comprises the steps of:preparing a steel slab comprised of 0.02 to 0.10 wt % C, 0.50 wt % or less Si, 0.4 to 1.5 wt % Mn, 1.0 to 8.0 wt % Ni, 0.1 to 1.5 wt % Mo, 0.8 wt % or less Cr, 0.01 to 0.08 wt % sol. Al, with the balance of Fe and unavoidable impurities;heating the slab to a temperature of from 1000.degree. C. to 1250.degree. C.;hot rolling the steel at a reduction rate of 20 to 60% at an austenite recrystallization temperature region and then at a reduction rate of 30 to 70% at an austenite nonrecrystallization temperature region and finishing the rolling at a temperature of 650.degree. C. or higher;quenching the steel by initiating water cooling at a temperature at or above the A.sub.r3 point thereof and terminating the water cooling at a temperature of 150.degree. C.