VD低碱度渣对GCr15轴承钢夹杂物的影响

Effect of VD Low Basicity Slag on Inclusions of GCr15 Bearing Steel

为了减轻铝脱氧GCr15轴承钢中B类和D类夹杂物的危害,开展了VD低碱度渣和正常碱度渣精炼的对比工业试验研究。结果显示,与正常碱度精炼渣相比,碱度为1.96的精炼渣可使连铸坯中塑性夹杂物比例由14.81%上升为40.65%;同时,全氧(T.O)含量由7.7×10^(-6)下降至4.9×10^(-6),全铝(T.Al)和酸溶铝(AlS)含量由279×10^(-6)、210×10^(-6)分别下降至80×10^(-6)、75×10^(-6)。热力学计算表明,低碱度精炼渣引起钢液中[Si]活度增大使复合夹杂中Al_(2)O_(3)(inc)含量下降,钢中酸溶铝(AlS)含量落在与塑性夹杂物平衡对应的等铝浓度线范围内,理论计算与试验结果吻合。VD低碱度渣精炼有利于实现轴承钢夹杂物塑性化控制。

In order to reduce the harm of B-type and D-type inclusions in Al deoxidized GCr15 bearing steel,a comparative industrial experimental study was conducted on refining VD low alkalinity slag and normal alkalinity slag.The results showed that when refining slag alkalinity was reduced from 9.34 to 1.96,the proportion of plastic inclusions in the steel increased from 14.81%to 40.65%.As the same time,the content of total oxygen(T.O)decreased from 7.7×10^(-6)to 4.9×10^(-6);the content of total aluminum(T.Al)and acid-soluble aluminum(AlS)decreased from 279×10^(-6)and 210×10^(-6)respectively to 80×10^(-6)and 75×10^(-6).Thermodynamic calculation shows that the increase of[Si]activity in the liquid steel causes the decrease of Al_(2)O_(3)(inc)content in the composite inclusion,and the acid soluble aluminum(AlS)content in the steel falls within the range of equal aluminum concetration lines corresponding to plastic inclusions,the theoretical calculations are consistent with experimental results.The VD refining with low basicity slag is beneficial for achieving control over the plasticization of inclusions in bearing steel.