Abstract: The chemical composition, scanning electron microscopy and auger electron spectroscopy were used to analyze the reasons of the strip fracture of high strength IF steel HC250IF containing phosphorus during straightening in pickling & rolling process. It is confinned that the content of B is too low and the segregation of P at grain boundary could not be inhibited,and the FeTiP or Fe3P compound formed at the grain boundary resulting in brittleness is the basic cause of strip fracture. By optimized process for adding boron, increasing the content of B from 0.0002% 〜0.0007% to 0.0008% ~ 0.0012% , controlling strictly the content N≤ 30 x 10^-6 and vacuum cycle for 8 min after adding the boron iron in RH process, it is to ensure the uniformity of the composition, the strip fracture of high strength IF steel containing phosphorus during straightening in pickling & rolling process can be effectively avoided.

Key words: High Strength IF Steel Containing Phosphorus, Strip Fracture, Phosphorus Segregation, Boron ,

摘要： 采用化学成分、扫描电镜及俄歇电子能谱等手段分析了含P高强IF钢HC250IF酸轧拉矫断带原因,明确B含量低未能抑制P的晶界偏聚,形成的FeTiP或Fe₃P化合物导致晶界脆性是酸轧拉矫断带的根本原因。通过优化加硼工艺、提高钢中B含量从0.0002%～0.0007%升至0.000 8%～0.0012%、严格控制N含量≤30×10^-6、RH添加硼铁后真空净循环≥8 min保证成分均匀性的措施可有效避免含P高强IF钢酸轧拉矫断带

关键词: 含P高强IF钢, 断带, 磷偏聚, 硼