亚共析钢温变形过程中流变行为及组织演变规律研究

Study on Flow Behavior and Microstructure Evolution Rule of Hypoeutectoid Steel During Warm Deformation

以45钢为研究对象,通过热模拟压缩试验对试样进行温压缩,变形温度550~700℃,应变速率0.001~1s^(-1),变形量50%。结果表明:在变形温度550℃,应变速率1 s^(-1)时,造成应力快速下降的主要原因是变形功导致的温升所致,部分再结晶导致的软化也是造成应力下降的重要原因;温变形引起渗碳体破碎,且应变速率较低时,引起破碎渗碳体颗粒的分解并球化;构建了材料在应变为0.4的本构方程。

Taking 45 steel as research object, the warm compressing was completed on the thermal-simulator under deformation at 550℃ to 700℃, strain rate of 0.001 s-1 to 1 s-1 and deformation of 50%. The results show that, under deformation at 550℃, and strain rate of 1s-1, the temperature increasing caused by deformation work is the main reason for the flow stress rapidly decreasing with the strain increasing, and the soften caused by partial recrystallization is the important reason for the decrease of flow stress. Warm deformation causes the fracture of Fe3C, and under low strain rate, the decomposing and nodulizing of broken Fe3C particle are caused. The constitutive equation is established at strain of 0.4.