特厚钢板探伤不合格原因分析及控制

Cause Analysis and Control of Disqualified Extra Heavy Plate in Flaw Detection

针对莱钢4300 mm宽厚板产线在实际生产中130 mm特厚钢板探伤不合格的问题,从金相组织、化学成分、工艺等方面展开分析研究,发现由于受到连铸坯厚度限制,连铸坯压缩比过小,加之粗轧阶段轧制道次较多,压下率不足,导致连铸坯内部疏松、缩孔等缺陷难以轧合。通过对连铸坯成分、铸坯缓冷、中间坯倍数、控轧控冷、轧后钢板缓冷等工艺进行调整,探伤合格率得到明显提高。

For the problem of disqualified 130 mm extra heavy steel plate in flaw detection in Laiwu 4300 mm extra heavy steel plate production line,metallographic structure,chemical composition and process are analysed and investigated.The results show that due to the limitation of slab thickness,the low compression ratio,too many rolling passes at roughing stage and insufficient reduction ratio results in difficult rolling fusion of looseness and shrinkage inside slab.By trimming slab composition and various process parameters such as slab slow cooling,intermediate bar multiplier,controlled rolling and controlled cooling,as-rolled plate slow cooling,the flaw qualification rate is significantly improved.