摘要
轴承钢主要用于制造轴承的滚动体和套圈。钢中的氧化物夹杂会影响轴承的疲劳寿命,因此在生产中需严格控制其类型、数量和尺寸。为进一步提高某钢厂GCr15轴承钢钢水的洁净度,通过全流程系统取样,并利用夹杂物自动分析扫描以及热力学计算等手段对该工艺生产的轴承钢中夹杂物的特性和演变规律进行了研究。结果表明,LF化渣时夹杂物主要为Al_(2)O_(3),LF出站时逐渐演变为MgO-Al_(2)O_(3)和CaO-(MgO)-Al_(2)O_(3),尺寸主要分布在1~5μm;VD精炼结束时夹杂物数密度由LF出站时的19.51个/mm^(2)降低至16.84个/mm^(2),尺寸1~2μm和2~5μm夹杂物占比分别为68.7%和27%;中间包夹杂物数密度进一步降低至15.59个/mm^(2),此时夹杂物类型和尺寸分布与VD出站时相似。铸坯中夹杂物数密度较中间包大大减少,仅为7.9个/mm^(2),但夹杂物尺寸明显增加,且硫化物夹杂占比增加。热力学计算表明,冶炼过程钢中极易生成MgO-Al_(2)O_(3);但当钢中w(Mg)为0.0006%时,只要w(Ca)>0.0003%,MgO-Al_(2)O_(3)就可以向CaO-Al_(2)O_(3)转变。此外,采用FactSage 8.3软件计算了钢液冷却过程中夹杂物的相转变和成分变化。
Bearing steel is mainly used to manufacture the roller and ring of bearing.Oxide inclusions in steel affect the fatigue life of bearings,so their type,quantity and size need to be strictly controlled in production.In order to improve the cleanliness of GCr15 bearing steel in a steel plant,the characteristics and evolution mechanism of inclusions in the steel were analyzed firstly through systematic sampling,automatic analysis and scanning of inclusions and thermodynamic calculation in the present study.The results showed that the inclusions in molten steel were mainly Al_(2)O_(3)after the slag melting during LF refining,and gradually evolved into MgO-Al_(2)O_(3)and CaO-(MgO)-Al_(2)O_(3)at the end of the LF refining,and the size was mainly distributed in 1-5μm.The number density of inclusions at VD end decreased from 19.51 mm-2 to 16.84 mm-2,and the proportion of 1-2μm and 2-5μm inclusions were 68.7%and 27%,respectively.The number density of inclusions in tundish was further reduced to 15.59 mm-2,and the distribution of types and sizes of inclusions was similar to that at VD end.The inclusions number density in the billet decreased to 7.9 mm-2,but the size of inclusions increased significantly and the quantity of sulfide also increased.Thermodynamic calculations showed that MgO-Al_(2)O_(3)was easily generated in the steel during smelting when no Ca,and would be transformed into CaO-Al_(2)O_(3)when w(Mg)in the steel was 0.0006%and w(Ca)was more than 0.0003%.In addition,the phase transition of inclusions and composition changes during cooling and solidification were calculated by FactSage 8.3 software.
作者
王华军
陈刚
王凯民
李伟涛
姜传辉
唐海燕
WANG Huajun;CHEN Gang;WANG Kaimin;LI Weitao;JIANG Chuanhui;TANG Haiyan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Weifang Special Steel Group Co.,Ltd.,Weifang 261000,China)
出处
《炼钢》
CAS
北大核心
2024年第5期89-97,共9页
Steelmaking
基金
国家自然科学基金资助项目(51874033)。
关键词
GCR15轴承钢
非金属夹杂物
热力学
凝固
演变
GCr15 bearing steel
non-metallic inclusions
thermodynamics
solidification
evolution
