单绕组螺旋电磁搅拌对高碳大方坯中心偏析影响的研究

Research on the Influence of Single Winding Helical Electromagnetic Stirring on the Center Segregation of High Carbon Large Square Billet

本工作自主开发了一种新型的螺旋电磁搅拌器(单绕组),并研究了单绕组线圈所激发的螺旋电磁场对含碳量为0.75%(质量分数)的钢铸坯(大方坯)的元素分布的影响。研究结果表明,螺旋电磁搅拌的电流、搅拌频率以及搅拌方式都会显著影响合金元素的分布。当对铸坯进行反螺旋型搅拌时,螺旋搅拌的电流越大(400 A以上)、频率越高(6 Hz以上),碳元素的偏析程度越低。采用电火花原位分析测定了搅拌前后铸坯的碳元素偏析程度,结果表明,对螺旋电磁搅拌的参数进行优化后,铸坯中心区域的碳元素的统计偏析度可降低50%以上(95%的置信区间)。

In this work,a new type of helical electromagnetic stirrer(single winding)was developed,and the influence of helical electromagnetic field excited by single winding coil on the element distribution of steel billet(large square billet)with carbon content of 0.75%(mass fraction)was also investigated.The results indicated that the current,stirring frequency and stirring mode of spiral electromagnetic stirring will significantly affect the distribution of alloy elements.In the reverse helical stirring mode,the higher the current and frequency of spiral stirring are(higher than 400 A and 6 Hz,respectively),the more significantly element segregation of billet will be improved.The segregation degree of alloy elements before and after stirring was measured by spark in-situ analysis.It is found that the statistical segregation degree of carbon elements in the central area of billet can be reduced by more than 50%(95%confidence interval)after stirring through helical electromagnetic field with optimized parameters.