汽车轴承部件异常开裂的电子探针分析

Analysis of abnormal cracking of automotive bearing component by electron probe micro analyzer

使用电子探针对某汽车轴承部件在成型过程中出现的开裂失效进行了解析,解释了出现失效裂纹的主要原因是部件中间位置出现元素硫的偏析聚集使得中间位置不易形成与其他位置一致的铁素体+珠光体组织,而能够细化晶粒的元素铝的负偏析导致中间位置形成粗大的铁素体组织,另外,粗大的非金属复合夹杂物的存在进一步割裂了基体性能的连续性,恶化了中间位置的综合性能。结果表明,电子探针高灵敏度的特征,能够直观地表征微量元素铝和硫的偏析分布。同时,可借助电子探针背散射检测器高灵敏度的特点,直接进行渗层的观察和评价。

The failure of a certain automobile bearing part during forming process was analyzed by using electron probe micro analyzer. It was explained that the main reasons for the failure crack were that the segregation and accumulation of elemental sulfur in the middle of the component made it difficult to form ferrite+pearlite structure as other positions,while the negative aggregation of elemental aluminum which could refine the grain size led to the formation of coarse ferrite structure in the middle location. In addition, the existence of coarse non-metallic inclusions further split the continuity of matrix properties,deteriorating the comprehensive performance of the intermediate position. The result showed that the segregation distribution of trace elements aluminum and sulphur could be visually characterized by electron probe micro analyzer. Also, the characteristic of high sensitive back scattered electron detector could be used to directly observe and evaluate the surface treatment layer.