宽厚板典型表面缺陷及其控制

分析了包钢宽厚板出现的钢板星裂、表面横裂纹、边直裂纹等缺陷产生的原因。通过将微合金钢w(N)控制在40×10-6以下,动态调节连铸过程冷却水量以保证铸坯矫直温度保持在塑性区域范围内,合理选取连铸过程中的保护渣,提高铸坯出加热炉温度,减少轧机辊道冷却水对钢板下表面温降影响,减少上下表面温差以减轻由轧制过程中上下表面金属流动性差异造成的折叠程度等措施,钢板星裂、表面横裂纹、边直裂纹等缺陷得到了有效控制,提高了产线热装热送率及钢板的成材率。

Typical surface defects of heavy plate and their controlling

The causes of the star crack,the surface transverse crack and the straight edge crack of heavy plate in Baotou Steel were analyzed.By controlling nitrogen content of microalloyed steel below 40 × 10-6,dynamic adjusting the cooling water volume in continuous casting process to ensure the straightening temperature of slab in the plastic area,reasonable selecting the mould powder in continuous casting process,increasing the slab pushing out temperature in heating furnace,reducing the influence of cooling water of mill roller on the temperature drop of the bottom surface of plate,decreasing the temperature difference between the upper surface and the bottom surface to relieve the folding extent caused by metal liquidity differences,the defects such as star crack,surface transverse crack,straight edge crack and so on were controlled effectively.Both the hot delivering and charging rate of the production line and the yield of plate were improved.