终轧温度对高强度工程机械用钢组织性能的影响

Effect of Finishing Rolling Temperature on Microstructures and Mechanical Properties of Steel Strip for Engineering Mechanism

对不同终轧温度的高强度工程机械用钢热轧钢卷进行了力学性能和金相组织的测试,研究了终轧温度对其组织和性能的影响。试验结果表明,随着终轧温度的降低,试验钢的抗拉强度和屈服强度降低,延伸率升高。高温终轧试样的低温冲击值很低,随着终轧温度的降低,低温冲击值大幅度升高。高温终轧试样的金相组织是铁素体+微量的珠光体,铁素体组织均匀性较差;中温终轧和低温终轧试样的组织是铁素体+珠光体,铁素体晶粒比较规则,而且低温终轧的均匀性比中温终轧好。高温终轧试样的铁素体晶界明显存在M3C型复合条状或短棒状的碳化物。

Effect of finishing rolling temperature on microstructures and mechanical properties of steel strip for engineering mechanism was studied by means of optical microscopy,SEM,TEM,tensile property testing and impact toughness testing.The results show that tensile strength and yield strength of testing steel decrease and elongation increase with the decrease of finishing rolling temperature.The value of low temperature impact toughness with high finishing rolling temperature is very low,while it increases a lot as finishing rolling temperature decrease.The microstructure of testing steel with high finishing rolling temperature consists of ferrite and a little pearlite,which is inhomogeneous.While with intermediate and low finishing rolling temperatures,the microstructure of it contains ferrite and pearlite,and the ferrite grain is regular.The microstructure of testing steel with low finishing rolling temperature is more homogeneous than that with intermediate finishing rolling temperature.Strip-like or rod-like multicarbides M3C exist on the grain boundary of ferrites with high finishing rolling temperature.