高强船板钢拉伸试验断口不合的原因分析和改善措施

通过低倍酸浸、断口形貌、金相组织等分析方法,对高强度船板拉伸断口不合的原因进行了研究,并且分析了浇注过程中辊缝收缩、二次冷却、扇形段接弧和辊缝精度对铸坯质量的影响。研究结果表明:连铸坯的中心偏析和中间裂纹造成的异常组织和长条状MnS夹杂是断口不合的主要原因;采取优化辊缝收缩方案、加强二冷系统和扇形段的管理,铸坯中心偏析指数和裂纹指数明显降低,高强船板断口合格率稳定在97%左右。

Improvement Measure of Sub-Fracture During Tensile Test of High Strength Ship Plate

Reasons for tensile fracture of high strength ship plate was discussed by means of acid soak,fracture pattern,microstructure analysis,and analyzed influnce of the slab quality,such as roll gap shrinkage,second cooling,accuracy of arc and roll gap,on quality of casted billet.Analysis results showed that: abnormal structure formed by central segregation and halfway cracks and strip-MnS are the major causes for unqualified fracture;index of the center segregation and halfway crack significantly was reduced rem...