Abstract
The mechanical properties and hardenability of multiple low-alloy high-strength steels, such as containing 0.3%C, 1.00%Cr, 0.3%Cu, 0.01%Ti, 0.002%B and 0∼0.5%Mo were studied. These steels have considerable excellent mechanical properties and hardenabilitys, even with no added Mo. By addition of Mo, the strength, the toughness and the hardenability of these steels were improved, and it was found that addition of 0.4∼0.5%Mo in these steels was most effective. The low-temperature transition properties in these steels, oil quenched and tempered to obtain Rc 32 hardness, were remarkably improved by addition of Mo. 0.42%Mo-added steels maintained about 5 kg-m V-nooch Charpy impact energy at −78°C a very high value for high strength steel which has the tensile strength over 100 kg/mm2.
