Fe-Mn-1.6 Ni-C水电用钢板轧后 直接淬火和回火工艺

通过Fe-Mn-1.6Ni-C钢板控制轧制、轧后直接淬火和560~710℃回火调质处理实验，研究了轧后直接淬火态和回火态的组织与性能变化.结果表明，轧后直接淬火得到组织细小的板条马氏体，固溶强化作用提高了其抗拉强度.经过回火热处理后，碳化物的析出及其对位错的钉扎作用，降低了钢的抗拉强度，提高了钢的屈服强度.随着回火温度的升高，碳化物聚集长大，铁素体发生回复与再结晶，造成强度下降以及冲击韧性提高.当回火温度高于A_○c1时，粗大的碳化物极易引起裂纹形核，破坏钢的冲击韧性.Fe-Mn-1.6Ni-C钢最优的回火温度为680℃，屈服强度为963MPa，抗拉强度为988MPa，延伸率为20.0%，-60℃冲击功为142J.

Direct Quenching After Rolling and Tempering Processes of Fe-Mn-1.6Ni-C Steel Plate for Hydropower Station

The microstructure and mechanical properties of Fe-Mn-1.6Ni-C steel plate after direct quenching and tempering were investigated， where the tested steel was processed by controlled rolling， direct quenching and 560~710℃ tempering. The results show that the fine lath-martensite is obtained by direct quenching after rolling and the improved tensile strength of the experimental steel after direct quenching is mainly from solid solution strengthening. After tempering， the tensile strength of the steel decreases and the yield strength increases， which is mainly caused by the carbide precipitation and the pinning effect of the precipitates on the dislocations. Due to the aggregation and growth of carbides and recovery and recrystallization of ferrite， the strength decreases and the impact toughness increases with the increasing temperature of tempering. However， the coarse carbides can be observed in the steel if the temperature of tempering is higher than A_○c1， which facilitate the nucleation of micro-cracks and decrease the impact toughness. An optimum tempering temperature of Fe-Mn-1.6Ni-C steel can be obtained， which is 680℃， associated with the yield strength of 963MPa， the tensile strength of 988MPa， the elongation of 20.0%， and the -60 ℃ impact energy of 142J.