27SiMn钢表面裂纹形成原因分析及控制措施

Analysis and Control of Surface Crack Defect of 27SiMn Steel

针对27SiMn钢轧材表面经常出现裂纹缺陷的问题,对问题钢材进行了取样分析,找到引起表面裂纹的原因并提出控制措施。利用金相显微镜及扫描电镜对裂纹进行观察。分析结果表明,钢材化学成分及力学性能符合设计要求,裂纹两侧有明显的脱碳层,裂纹内有大量Si-Al氧化物,确定裂纹为铸坯原有裂纹;结合实际生产情况,将铸坯矫直温度由900℃提升至930℃,钢材表面裂纹消失。

There are often slab crack defects on the surface of 27SiMn Steel.The problem of steel was analyzed to look for the causes of surface cracks and control measures were put forward. The crack was observed by optical microscope and scanning electron microscope.The analysis results show that the chemical composition and mechanical properties of the steel meet the design requirements.There are obvious decarburized layer on the both sides of the crack and a lot of Si-Al oxide in the crack.It's certained that the crack is the original crack of the cast. Combinding with the actual production situation, when the temperature is raised from 900 ℃to 930℃, the surface crack on the steel surface is gone.