16Mn轴座裂纹原因分析及解决措施

Analysis and Solution on Crack of 16 Mn Steel Axle Seat

采用"30 t EAF→LF→VD→铸锭"工艺冶炼16Mn钢锭,钢锭经锻造成轴座经加工后探伤发现密集性缺陷。通过化学成分、低倍分析、金相显微分析、能谱分析、硬度试验以及数值模拟对产生的缺陷进行分析研究,并提出改进措施。结果表明:宏观检测受检面有许多微裂纹,裂纹附近有灰色Mn S夹杂物。分析表明,裂纹是钢锭凝固收缩时得不到钢液补充形成。通过优化浇注工艺,严格控制熔炼浇注温度、钢锭模烘烤及冒口充填速度,得到了合格钢锭。

The metallurgical process flow of 16Mn ingot is： 30t EAF→LF→VD→ casting ingot. Dense defects were found on axle seat forged from 16Mn ingot by ultrasonic inspection. Chemical analysis, macroanalysis, metallographic microscopic analysis, energy spectrum analysis, hardness testing and numerical simulation were carried out and modification measures were put forward. The results show that many micro cracks exist due to the lack of molten steel when the steel ingot shrinks. Gray MnS inclusions were detected due to segregation of Mn and S elements near the cracks. The qualified ingots were obtained through strictly controlling the melting and pouring temperature, the baking of the ingot mold and the filling rate of the riser.