20CrMnTi热轧圆钢表面裂纹成因分析及改进

Cause Analysis and Improvement of Surface Crack of 20CrMnTi Hot Rolling Round

运用金相及电镜能谱分析的方法,对天钢生产的Ф50 mm 20CrMnTi热轧圆钢表面裂纹的成因进行了分析,找到了产生该问题的具体原因,提出了改进措施。在铸坯生产中,采用全程保护浇注并控制钢水中氮含量不超过50 ppm、控制浇注过程中中包钢水重量始终保持在24~25吨、控制中包水口插入深度在80~120mm、控制连浇炉数不超过15炉、控制结晶器液位波动不超过±3%,可以保证铸坯质量稳定良好。

By means of metallography and electron microscope energy spectrum analysis,the causes forthe surface crack of囟50mm20CrMnTi hot rolling round were analyzed.Specific reasons were found outand improvement measures put forward.During the production of billet,fully submerged casting wasadopted and the nitrogen content of molten steel controlled within50ppm.During casting,steel weightin tundish was kept between24to25tons and nozzle insertion depth within a range of80to120mm.The number of sequence casting heat was controlled less than15and mould level fluctuation within依3%.In this way,billet quality could be ensured.