Abstract: In order to explore the problems and improvement methods of the current production process of 37Mn5 steel for oil casing smelting in a steel mill， in this paper the whole process sampling analysis of two consecutive heats in the industrial production of the steel plant， including metallographic specimen， oxygen and nitrogen rod and refined slag sample， was conducted. After optimization and improvement， the final conclusions are as follows：（1）secondary oxidation occurs in different degrees in the LF refining and VD calcium treatment stage， specially feeding calcium line stage reaction is more violent ， which is easy to cause the secondary oxidation of the liquid steel and increasing of Ds inclusions.  By optimizing the refining deoxyoperation， the amount of calcium line feeding is reduced from 1.4-1.7 m/t to 0.95 m/t， and all kinds of inclusions are grade ≤1.5， and the qualified rate is 100%；（2） the composition analysis of refining slag shows that the residue components in the ternary phase diagram are all outside the liquid phase region， which results in poor melting performance and poor liquidity of the refining slag. By increasing SiO₂ in the slag from to 9%-12%， Al₂O₃ to 25%-30%， and controlling the binary alkalinity at 5-8， it can improve the melting and fluidity of the slag， strengthen the coverage capacity of the slag， and effectively prevent secondary oxidation；（3） compared to the VD stage， the oxygen and nitrogen content in the tundish casting stage is basically stable， but the number of inclusions has been increased to a certain extent， and the growth rate of the inclusions is far higher than the endogenous rate of the inclusion， therefore， the source is from slag rolling， the smooth casting of the tundish shall be kept， at the same time to avoid the occurrence of dropping off slag phenomenon of the ladle.

Key words:  , 37Mn5 Steel； Whole Process Analysis； Petroleum Casing Steel； Process Optimization； Slag System Optimization

摘要： 为探究某钢厂当前冶炼37Mn5钢过程中所存在的问题，对生产中连续两个炉次进行全流程取样分析，包括金相样、氧氮棒以及精炼渣样，经优化改进，最终得到的结论如下：（1）在LF精炼阶段以及VD钙处理阶段有不同程度的二次氧化现象产生，尤其喂钙线阶段反应较为剧烈，容易引起钢液二次氧化，导致Ds类夹杂物增加，通过优化精炼脱氧操作，钙线喂入量由1.4～1.7 m/t降低至0.95 m/t，各类夹杂物均≤1.5级，合格率100%；（2）精炼渣的成分分析得出，三元相图中渣成分点都在液相区以外，导致精炼渣熔化性能不好，流动性较差，通过提高渣中SiO₂至9%～12%，Al₂O₃至25%～30%，将二元碱度控制在5～8，可提高渣的熔化性、流动性，渣的覆盖能力加强，有效防止二次氧化；（3）中间包浇注阶段相比于VD阶段，氧氮含量基本稳定，但夹杂物数量有一定的提升，夹杂物增长速率远超夹杂物内生速率，因此，其来源为卷渣，应保持中间包平稳浇注，同时避免钢包下渣现象发生。

关键词: 37Mn5钢, 全流程分析, 石油套管钢, 工艺优化, 渣系优化