温度应力对低碳微合金钢连续冷却过程中相变塑性的影响

Effect of temperature stress on transformation plasticity of low-carbon microalloyed steel during continuous cooling

通过热模拟单轴载荷拉伸/压缩试验,研究了连续冷却过程中温度应力对低碳微合金钢700L相变塑性和相变动力学的影响。结果表明,在1/2奥氏体屈服强度的应力范围内,700L钢的相变塑性应变与温度应力呈线性关系,对应相变塑性参数k为1.357×10-4;整体而言,压应力对700L钢相变塑性的作用效果强于拉应力。连续冷却过程中,外加载荷明显降低了700L钢奥氏体向铁素体转变开始温度,延缓了铁素体相变进程,缩短了相变完成所需时间,并且拉应力作用对700L钢铁素体转变动力学的影响效果更显著。

Through thermal tensile/compressive experiments under uniaxial loads,the effects of temperature stress on the transformation plasticity and transformation kinetics of low-carbon microalloyed steel 700L during continuous cooling process were investigated.The results show that within the stress range of 1/2 austenite yield strength,there is a linear relation between transformation plastic strain and temperature stress of 700L steel,and the corresponding phase transformation plasticity parameter k is 1.357×10-4;overall,the compressive stress has a more significant influence on the transformation plasticity of 700L steel than the tensile stress.During continuous cooling process,the applied uniaxial load significantly reduces the starting temperature of austenite to ferrite transformation,delays the ferrite phase transition process,and shortens the time required for the complete phase transition of 700L steel;on the whole,the effect of tensile stress on the ferrite transformation kinetics of 700L steel is more significant than that of the compressive stress.