铬合金化Q&P钢的热处理工艺优化与碳配分行为

Heat treatment optimization and carbon partitioning behavior of Cr-alloyed Q&P steel

设计出新型Cr合金化(>2%)Q&P钢,研究了淬火及配分工艺对其组织与性能的影响,并通过热动力学计算评估了Cr对Q&P钢残留奥氏体体积分数及碳配分行为的影响。结果表明,淬火温度为230℃及配分温度为400℃条件下,Cr合金化Q&P钢获得了最佳的强塑性匹配(抗拉强度1180 MPa,断裂总延伸率18.6%),强塑积达到21 GPa·%;同时,400℃配分温度下,在较宽的淬火温度区间内(210~270℃),Q&P钢强塑积均超过19.5 GPa·%。热动力学计算结果表明,相比常规成分Q&P钢,Cr合金化提高了配分过程中奥氏体碳含量从而提高了Q&P钢中残留奥氏体体积分数及稳定性。

A new type of Cr-alloyed(>2%)Q&P steel was designed,and the effects of quenching and partitioning processes on the microstructure and properties of the tested steel were studied.The effect of Cr on the volume fraction of retained austenite and carbon partitioning of the Q&P steel was evaluated through thermodynamic calculations.The results show that when the quenching temperature is 230 C and the partitioning temperature is 400 C,the Cr-alloyed Q&P steel obtains the best strength-plasticity matching(tensile strength of 1180 MPa,percentage total extension at fracture of 18.6%),and the strength-elongation product reaches 21 GPa·%.At the same time,in a wide quenching temperature range(210-270 C),the strength-elongation product exceeds 19.5 CPa·%.Thermodynamic calculation results show that compared with conventional composition Q&P steel,Cr-alloying increases the carbon content in austenite during the partitioning process,thereby increasing the volume fraction and stability of retained austenite.