卷取温度对含Mo DP780钢组织和性能的影响

THE INFLUENCE OF COILING TEMPERATURE ON THE STRUCTURE AND PROPERTIES OF Mo DP780 STEEL

利用Gleeble-3500热模拟实验机模拟了卷取温度对含Mo DP780钢的组织和性能的影响,测定了热轧过程中的相变,并得到了动态CCT曲线。采用光学显微镜和扫描电子显微镜分析了钢的组织形貌,用洛氏硬度仪测定了试样的硬度,并分析了实验钢的性能。结果表明:卷取温度在480℃以下时,其对含Mo DP780钢的组织和性能影响较大,随着卷取温度的升高,钢的强度逐渐降低,且相变都是在卷取之前发生;卷取温度在480℃以上时,随着卷取温度升高,钢的组织和性能几乎不变,且相变均发生在卷取之后,组织是粒状贝氏体+马氏体,在低温段开始发生马氏体转变。含Mo DP780钢热轧后的组织为贝氏体+马氏体和残余奥氏体的混合组织。

The effect of coiling temperature on the structure and properties of Mo DP780 steel was simulated by Gleeble-3500 thermal simulation machine.The phase transformation during hot rolling was measured and the dynamic CCT curve was obtained.The microstructure was analyzed by optical microscope and SEM,and the hardness was measured by Rockwell hardness tester,and the properties of the steel were analyzed.The results showed that when the coiling temperature was lower than 480℃,it had obvious effect on the structure and properties of Mo DP780 steel,with the increasing of coiling temperature,the strength of DP780 steel decreased gradually,and the transformation occured before coiling;while when the coiling temperature was over 480℃,with the increasing of coiling temperature,the microstructure and properties of steel almost remaine d unchanged,and the transformation occured after coiling,its microstructure is granular bainite+martensite,and martensite transformation begined at low temperature.After hot rolling,the microstructure of Mo DP780 steel is a mixture of bainite,martensite and retained austenite.