列车缓冲器弹簧淬火开裂原因分析

Quenching Cracking Reason Analysis of Spring Using for Train Buffer

某列车缓冲器弹簧在淬火后出现了纵向裂纹;利用化学成分分析、硬度检测、断口分析、夹杂物和显微组织分析等手段对弹簧淬火开裂原因进行了分析。结果表明:原材料组织中的带状偏析和沿轧制方向分布数量多且粗大的非金属夹杂物是弹簧淬火开裂的主要原因;夹杂物和带状偏析造成材料组织和性能均匀性变差,粗大的非金属夹杂物成为裂纹源,在组织应力的作用下,促进裂纹形成并迅速扩展成为沿轧制方向分布的淬火裂纹。

The vertical-cracking on spring buffer of a train produced were tound after quenching, Quenching cracking reason of the spring was analysis by using chemical compositions analysis, hardness test, facture analysis, inclusion and microstructure observation. The results show that the main reasons of the cracking were the thick, big and large amount of zonal segregation and large nonmetallic inclusions which were distributed in rolling direction of the materials during the quench hardening. The inlusion and the zonal segregation made the homogeneity of microstructure and properties get worse, the large nonmetallic inclusions became the crack region. The crack was formed and propagated as a function of structure strain.