大秦铁路钢轨断裂原因分析
Fracture Analysis of Rail of Daqin Railway
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摘要: 大秦铁路某钢轨在铺设的过程中断裂,同批钢轨使用后在钢轨踏面出现早期横向裂纹.采用断口宏观观察,金相组织分析,能谱分析等方法,对钢轨出现早期伤损的原因进行了综合分析.结果表明:钢轨踏面存在擦伤,摩擦导致局部金属产生高温,随后快速冷却产生白层.白层组织硬而脆,在外力作用下容易破碎,导致钢轨踏面早期出现横向裂纹.裂纹向轨头内部扩展最终导致钢轨铺设时断裂以及使用后出现早期疲劳核伤.Abstract: A rail cracked during the laying process. Transverse cracks appeared on the tread of the same batch of rail after using for a while. The failure reason of the rail was analyzed by facture surface observation, microstructure examination and energy spectrum analysis. The results indicate that scratch was found on the tread of rail. The friction led to high temperature of the rail metal and the white layer formation after fast cooling. The hard and brittle white layer is fragile, resulting in transverse crack on tread of rail. The crack propagated, leading to transverse fracture and early oval flaws.