100t BOF-LF-RH-CC流程冶炼GCr15轴承钢非金属夹杂的演变  

Evaluation of Nonmetallic Inclusions in Bearing Steel GCr15 Steelmaking by 100 t BOF-LF-RH-CC Flowsheet

作　　者：刘佳伟[1] 岳峰[2] 王子健[3] 

机构地区：[1]北京科技大学工程技术研究院,北京100083 [2]北京科技大学钢铁共性技术协同创新中心,北京100083 [3]江苏沙钢集团淮钢特钢股份有限公司总工办,淮安223002

出　　处：《特殊钢》2017年第3期61-65,共5页Special Steel

摘　　要：试验GCr15轴承钢(/%:1.00C,0.20Si,0.39Mn,0.015P,0.005S,1.50Cr,0.003Ti,0.015Als)的冶炼工艺流程为预脱硫铁水-100 t BOF-LF-RH-200 nm×200 mm坯连铸。主要工艺特点为BOF出钢过程加1.2 kg/t铝脱氧,LF精炼采用白渣操作,精炼初渣主要成分为(/%:22Al_2O_3,56CaO,10SiO_2,5MgO),RH 67 Pa,25 min,连铸过程保护浇注。两炉钢冶炼分析结果表明,钢中氧氮含量在RH破空样品中同时达到最低分别为7×10^(-6)~8×10^(-6)和24×10^(-6)~26×10^(-6),钢中非金属夹杂尺寸主要集中在3~8μm,并且单位面积夹杂物数量在RH破空样中达到最小;铸坯中非金属夹杂以Al_2O_3-CaO夹杂为主;在高碱度渣的条件下,钙铝酸盐与镁铝尖晶石很容易发生反应,碱度为2~3时会出现少量MgO-Al_2O_3,在渣碱度达到4以上时不会出现MgO-Al_2O_3系夹杂物,并且高碱度条件下MgO-Al_2O_3-CaO系夹杂物中MgO含量会降低。The steelmaking flowsheet of tested bearing steel GCrl5 （/% ： 1.00C, O. 20Si, 0. 39Mn, 0. 015P, O. 005S, 1.50Cr, O. 003Ti, 0. O15Als） is pre-desulphurized hot metal- 100 t BOF-LF-RH-200 mmx 200 mm billet cast- ing. The main process characteristics are adding 1.2 kg/t aluminium for pre-deoxidation in BOF tapping, using white slag operation in LF refining with initial slag main ingredient （/% ： 22A1203 , 56CAO, 10SiO2 , 5MgO）, RH 67 Pa for 25 min and shield casting in cast process. Analysis results of two heats malting show that the oxygen and nitrogen content in liquid at end RH are lowest respectively 7 x 10 -6 - 8 x10 -6 and 24 x 10 -6 - 26 x 10 -6, the size of majority inclusions in steel is 3 - 8 μm, and the number of inclusions in steel at unit area is lowest at end RH, and the main nonmetallic inclusions in cast billet are A1203-CaO; with condition of high basicity refining slag the calcium aluminate easily reacts with magnesium- aluminum spinel, with slag basicity 2 - 3 the small amount of MgO-A1203 occurs and with slag basicity more than 4 the MgO-A1203 series inclusions don＇t occur, besides with condition of high basicity the MgO content in MgO-A1203-CaO series inclusions is able to decrease.

关 键 词：100 t BOF—LF—RH—CC流程轴承钢GCr15夹杂物尺寸成分演变 

分 类 号：TF762.4[冶金工程—钢铁冶金]