齿轮钢铸坯碳偏析的改善

试验研究了100 t UHP EAF-LF(VD)-连铸流程生产的0.20%～0.40%C、CrMo和CrMnTi系列齿轮钢300 mm×340 mm铸坯断面的碳偏析。在正常生产条件下,将浇铸钢水过热度控制在15～25℃、二冷比水量在0.35L/kg、结晶器和末端电磁搅拌扭矩分别在18、15 cN·cm对铸坯碳偏析改善有利。生产实践检验结果表明,连铸坯修正碳偏析极差降到了0.025%以下,齿轮钢轧材低倍偏析评级基本都达到了2.5级以下。

Improvement of Carbon Segregation in Casting Bloom of Gear Steel

The carbon segregation at cross section of 300 mm x 340 mm casting bloom of CrMo and CrMnTi series gear steel containing 0. 20% ~ 0. 04% C produced by 100 t UHP EAF-LF (VD) -concasting flow sheet has been tested and studied. At normal production conditions, to control the casting liquid overheating extent 15 ~ 25 ℃ , the secondary cooling water rate 0. 35 L/kg, and the torque of mode and final electromagnetic stirring respectively 18 and 15 cN • cm is favorable to improve the bloom segregation. The verifying results in production practice show that the extreme different of corrected carbon content in bloom is less than 0. 025% and the rating of macro segregation of rolled products is less than 2. 5.