稀土在炼钢各工序含量变化规律研究

Study on Change Rules of Rare Earth Content in Each Process of Steel-making

生产25CrMoBVRE和U76CrRE试验采用钢包投入法加入稀土合金,经铁水预处理、转炉冶炼、采用脱氧合金化工艺,在LF钢包精炼采用深脱硫工艺,精炼后,钢水中硫含量及氧含量很低,对提高稀土收得率有积极作用。通过有效控制钢水的氧、硫含量,分别在VD前、后钢包中进行加入稀土镧硅钙铁合金、稀土铈铁合金,稀土加入量分别为0.012%和0.003%,试验结果表明,采取相应的保护浇注措施,未出现水口堵塞现象,生产工艺顺行,操作方便,稀土收得率分别达到15%和40%。成本降低分别为60%和50%。稀土在钢中分布均匀,有改善夹杂物作用,产品性能完全满足产品标准及用户使用要求。

In the experiment of producing 25CrMoBVRE and U76CrRE,the ladle input method was used to add rare earth alloy.After pretreatment of hot metal,converter smelting,deoxidization and alloying process,deep desulfurization process in LF ladle refining,the sulfur and oxygen contents in molten steel were very low,which had positive effects on improving the yield of rare earth.The rare earth La-Si-Ca-Fe alloy and Ce-Fe alloy were added into ladle before and after VD by effectively controlling the oxygen and sulfur contents in molten steel as well as the amount added were 0.012%and 0.003%respectively.The test results showed that there was no nozzle clogging,the production process was trouble-free,operations were convenient,yields of rare earth could reach 15%and 40%respectively as well as costs were reduced by 60%and 50%respectively by taking corresponding protective pouring measures.The distribution of rare earth in steel is uniform,which can improve inclusions.The properties of products can fully meet the requirements of product standards and customer use.