300mm厚度宽断面普板轧制后偏离角边部裂纹控制实践

Control practices for edge cracking after rolling of 300 mm thick wide-section plain plates

鄂钢的板坯铸造设备自投产以来已超过十年,但从2020年下半年开始,300 mm厚度的板坯断断续续轧制出距平均边部50~100 mm偏离角边部裂纹,300 mm厚轧制的钢板边裂比例高达19.8%,导致大量板坯无法通过边部切削处理后作为毛边板进行交付。通过多轮试验及分析找出关键因素,认为钢种成分、N含量对钢板裂纹的形成有一定的影响,通过修改工艺参数,钢水成分、控制氮含量,使300 mm厚度毛边板边部偏离角边部裂纹基本消失,边部裂纹控制在2%以下。

Egang Steel's slab casting equipment has been in operation for over ten years.However,since the second half of 2020,discontinuous cracks deviating from the edge by 50-100 mm have been observed in 300 mm thick slabs.The cracking ratio of the rolled steel plates with a thickness of 300 mm reached 19.8%,resulting in a significant amount of slabs that could not be delivered as hot-rolled plates after edge cutting.Upon identifying the crucial factors through multiple rounds of testing and analysis,it was found that the increase in speed,steel composition,and nitrogen content had a certain impact on the formation of steel plate cracks.By modifying the process parameters,adjusting the molten steel composition,and controlling the nitrogen content,the deviating edge cracks on the 300 mm thick hot-rolled plates were essentially eliminated,and the edge crack rate was controlled to below 2%.