合金元素微观偏析对车轮组织及断裂韧性的影响

Effects of Microsegregation of Alloy Elements on Microstructures and Fracture Toughness of Wheels

采用金相显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、拉伸试验、冲击试验、布氏硬度试验及断裂韧性试验研究了车轮钢中Mn、Si、Cr、V合金元素微观偏析对车轮金相组织和断裂韧性的影响。结果表明,车轮钢金相组织中大尺寸晶粒的存在是断裂韧性值偏低的直接原因。车轮轮辋的金相组织和合金元素微观分布在圆周方向上存在不均匀性,合金元素微观偏析导致了车轮金相组织和断裂韧性的不均匀。优化车轮钢连铸工艺,改善材料组织均匀性是提升车轮断裂韧性及其均匀性的关键。

Effects of microsegregation of Mn,Si,Cr and V elements on the microstructure and fracture toughness of wheels were studied by means of optical microscope(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),tensile test,impact test,brinell hardness test and fracture toughness test.The results show that the existence of large grain size in the metallography of wheels is directly responsible for the low fracture toughness.The microstructure and distribution of alloy elements in the wheel rim are not uniform in the circumferential direction.Inhomogeneity in microstructures and fracture toughness of the wheel is caused by the microsegregation of alloy elements.Thr optimization of the continuous casting process of wheel steels and the improvement the uniformity of material structure are the key to increase the fracture toughness and its uniformity of wheels.