应力对HQ785钢连续冷却贝氏体转变动力学的影响

Effect of stress on bainitic transformation kinetics in HQ785 steel with continuous cooling

利用Gleeble-1500热/力模拟试验机,研究了单向拉、压应力作用下HQ785钢连续冷却转变的CCT曲线及相变动力学曲线。结果表明,连续冷却转变时,外加应力使试验钢贝氏体相变开始温度明显提高;相同冷速下,拉应力比压应力对Bs的提高更为显著;拉、压应力都使试验钢的贝氏体转变区域变宽;拉应力对整个贝氏体相变都有显著的促进作用,而在压应力下,相变初始阶段受到抑制,应力越大抑制越明显。

The effect of tension/compression stress on the transformation kinetics and CCT diagram of HQ785 steel at continuous cooling transformation has been studied by Gleeble 1500 thermo mechanical simulator.The results show that with continuous cooling transformation the Bs temperature is increased by the applied stress,and at the same cooling rate,the Bs increase level with tension stress is more remarkable.Also the temperature ranges of bainitic transformation are enlarged by tension/compression stress.Tension stress evidently accelerates the transformation during the full bainitic transformation.While,under compression stress,the transformation was inhibited at the starting stage and the greater the stress,the more evident the inhibition.