连铸工艺参数对40Cr圆坯碳偏析的影响

Effect of CC process parameters on carbon segregation of 40Cr round billet

为降低直径为900 mm的40Cr连铸圆坯的碳偏析,提高钢材的性能与产品质量,从优化圆坯连铸工艺参数角度出发,分析了过热度、拉速、二冷强度以及电磁搅拌对铸坯碳偏析的影响。结果表明,当过热度控制在25~35℃范围内,拉速为0.75~0.85 m/min,二冷比水量为0.30 L/kg时,有利于改善铸坯碳偏析情况。对结晶器电磁搅拌以及末端电磁搅拌的参数测试分析得出,当结晶器和末端电磁搅拌电流以及频率参数分别设为180 A/3 Hz以及400 A/8 Hz时,铸坯碳偏析情况明显改善。采用优化后的连铸工艺参数进行生产试验,对20炉次对应的棒材横截面碳偏析情况进行跟踪测试,结果显示,碳偏析指数极差由优化前的0.07%~0.08%下降到0.04%以下。

In order to reduce the carbon segregation of round billet 40 Cr with a diameter of 900 mm and improve its properties and product quality,the effects of superheat,casting speed,secondary cooling strength and electromagnetic stirring on carbon segregation were analyzed from the point of view of optimizing round billet continuous casting process parameters.The results showed that when the superheat was controlled at 25-35℃,the casting speed was 0.75-0.85 m/min,and the specific water content was 0.3 L/kg,the carbon segregation of the slab was improved.The analysis of the parameters of the electromagnetic stirring of the crystallizer and the electromagnetic stirring at the end showed that the carbon segregation of slab was improved when the current and frequency parameters of crystallizer and end electromagnetic stirring were set to 180 A/3 Hz and 400 A/8 Hz,respectively.The production test was carried out with the optimized continuous casting process parameters,and the carbon segregation of the cross section of the bar corresponding to 20 heats was tracked and tested.The results showed the carbon segregation range of the slab was decreased from 0.07%-0.08%before optimization to below 0.04%.