Abstract: The causes of surface cracks formation of H beam of Nb-V microalloying steel BS55C-0. 14~0. 17C,0.45~0.55Si,1.25~1.45Mn,0.08～0. 10V,0.03～0.05Nb have been analyzed. The results showed that the steel was sensitive to longitudinal crack at solidification and its plasticity at 700~950 ℃ was lower,therefore,the cracks were easily produced at surface of H beam. Based on analysis of 168 heats production data of Nb-V microalloying steel BS55C,it was obtained that it was available to effectively decrease the surface cracks of H beam of Nb-V microalloying steel by using LF refining,controlling [s]≤0.015% and [P]≤0.020%,optimizing cast nozzle, adopting weak secondary water cooling and avoiding straightening at 700～900 ℃

摘要： 分析了成分为(%):0.14~0.17C,0.45~0.55Si,1.25~1.45Mn,0.08~0. 10V,0.03～0.05Nb H 型 钢BS55C表面裂纹形成原因。结果表明，该钢凝固时纵裂的敏感性较大，700~950℃范围内的塑性较低，使H 型钢表面易产生裂纹。由168炉Nb-V微合金化H 型钢BS55C生产数据分析得出，采用LF精炼，控制钢中S≤ 0.015%、P≤0.020%,优化浇铸水口，采用弱二次水冷工艺，避免在700~900℃范围矫直，可有效减少Nb-V微 合金化H 型钢的表面裂纹