ZG1Cr18Ni9Ti不锈钢铸件开裂原因分析

Analysis on Crack Reason for ZG1Cr18Ni9Ti Stainless Steel Casting

针对ZG1Cr18Ni9Ti材质的铸造壳体在生产过程开裂的问题,通过金相手段对裂纹缺陷进行了分析,发现铸件基体晶界处存在聚集的氮化钛。通过与原材料金相进行对比,确定了这种氮化钛是在原材料重熔凝固为铸件时形成的。铸件厚大部位凝固缓慢,导致氮化钛在晶界大量聚集从而形成裂纹源,在后续冷热加工应力的作用下壳体从晶界开裂。

The cracks detected in the production process of ZG1Cr18Ni9Ti casting were investigated. Using metallographic examination method, the TiN phase gathered in the grain boundary matrix was found. By comparing the mierostrueture with the raw material used for remelting, it can be obtained that the gathered TiN generates during the solidification process of the casting. Because of the slow solidifying rate in some part of the casting, TiN phase has enough time to be pushed into the grain boundary, and finally becomes to be the crack source, which can spread under hot and cold mechanical stress.