1990 Volume 76 Issue 9 Pages 1512-1519
Effect of γ/α dual-phase quenching on the mechanical properties of controlled-rolled low C-Mn-Nb-Ti-B steels has been studied with changing quench temperature, and carbon-and manganese-contents. The steels were heated to 1050°C, then controlled-rolled to 720°C. Contolled-rolled plates were directly water-quenched after rolling. High strength has been obtained by water-quenching from the temperatures in the γ/α dual-phase range after controlled-rolling. And the strength increases with increasing quench temperature. A major strengthening factor is increase in the amount of hard-phases, that is in this case, martensite and bainite with increasing quench temperature. It is found that high toughness can be obtained by keeping the amount of ferrite more than about 40% in volume when quenching from the temperature below 600°C, although toughness has been rapidly decreased by quenching from the temperatures above 650°C.
