论文部分内容阅读
针对焊接接头不能通过落锤检验问题,对钢轨母材和焊接接头进行取样,采用SEM、硬度、冲击、拉伸等分析方法,对比母材和焊接接头相同部位的断口微观形貌、金相组织、硬度、冲击性能和拉伸性能;采用网格法对夹杂物进行计量分析。结果发现,母材基体存在元素偏析,母材和焊态钢轨里存在大量分布极不均匀的非金属夹杂物;母材硬度波动大、冲击性能低、强度高、韧性差;采用正常焊接工艺所得到的接头力学性能有所提高,但品质不稳定;局部夹杂缺陷是引起钢轨断裂的本质原因。
Aiming at the problem that the welded joint can not pass the falling weight test, the rail base metal and the welded joint are sampled. The fracture microstructure, the microstructure of the same part of the base metal and the welded joint are compared with the SEM, hardness, impact and tensile analysis methods, , Hardness, impact properties and tensile properties; mesh method for inclusion analysis. The results showed that there was element segregation in the base metal matrix, and a large number of nonmetallic inclusions were distributed in the base metal and the welded steel rail. The hardness of the base metal was large, the impact performance was low, the strength was high, and the toughness was poor. The mechanical properties of the joints obtained have been improved, but the quality is not stable. The local inclusions defects are the essential causes of rail rupture.