降低工模具钢电渣重熔钢锭顶部缩孔缺陷的工艺实践

Process Practice for Reducing Top Shrinkage Cavity Defect of Electroslag Remelting Ingot of Tool and Die Steel

通过控制结晶器进水温度40℃,出水68℃;计算机自动补缩模型控制;自动补缩结束时,90 s内完成自耗电极至石墨电极切换,53 V,3 000 A通电熔炼3～5 min,再切换成自耗电极,50 V,4 000 A,通电6 min等工艺措施,使电渣重熔钢锭顶部缩孔缺陷深度由100 mm降低至30 mm。生产实践表明,补缩工艺操作简单易行,优化工艺生产的工具钢9Cr2Mo,Φ280 mm×1 000 mm,480 kg电渣钢锭210支;热作模具钢H13,420 mm×1 400 mm,1 500 kg电渣钢锭60支,没有再出现因钢锭顶部缺陷而造成锻造坯料报废,钢锭成材率显著提高。

With using the process measures including controlling mold inlet water temperature 40 ℃, outlet water temperature 68 ℃; controlling model of computer auto back feeding for shrinkage ; at end auto back feeding, changing con- sumable electrode to graphite electrode withing 90 s and power supply with 53 V, 3 000 A melting for 3 - 5 min, then again changing to consumable electrode and power supply with 50 V, 4 000 A for 6 min, the depth of top shrinkage cavity defect of electroslag remelting （ESR） ingot decreases to 30 mm from original 100 ram. Production practice shows that the process operation of back feeding for shrinkage is simple and easier to do. The forged billets of remelting 210 piece tool steel 9Cr2Mo Ф280 mm × 1 000 mm, 480 kg ESR ingot and 60 piece hot die working steel H13 Ф420 mm×1 400 mm, 1 500 kg ESR ingot by optimized process have not been rejected due to ingot top shrinkage cavity defect, the ingot yield increases obviously.