摘要
研究了轴承钢LF精炼和RH真空处理过程各类夹杂物的成分、种类和数量变化,并结合热力学模拟计算了夹杂物与钢液的界面参数,并对试验结果进行分析讨论。夹杂物分析结果表明,精炼25min后,脱氧产物Al_(2)O_(3)消失,钢中夹杂物以纯尖晶石、含少量CaO的尖晶石、CaO·2Al_(2)O_(3)和CaO·Al_(2)O_(3)为主。继续精炼65min至LF精炼结束,钢中夹杂物仍以纯尖晶石、含少量CaO的尖晶石、CaO·2Al_(2)O_(3)和CaO·Al_(2)O_(3)为主。RH真空处理25 min后,钢中夹杂物总数量较LF精炼结束降低75%,其中,纯尖晶石和含少量CaO的尖晶石去除率分别为99.5%和93.2%,CaO·2Al_(2)O_(3)去除率为67%。RH破空后钢中夹杂物以液态钙铝酸盐CaO·Al_(2)O_(3)和12CaO·7Al_(2)O_(3)为主。精炼过程尖晶石类夹杂物尺寸集中在10μm以下,尺寸大于20μm夹杂物主要为处于液相区的钙铝酸盐,这些钙铝酸盐在LF精炼前期就已经存在。与钢水接触角大于90°的固态夹杂物纯尖晶石、含少量CaO的尖晶石和CaO·2Al_(2)O_(3)在RH真空处理过程容易去除,与钢水接触角小于90°的液态夹杂物CaO·Al_(2)O_(3)和12CaO·7Al_(2)O_(3)不易去除。因此,将LF精炼结束的夹杂物控制为固态夹杂物有利于RH真空处理过程夹杂物的高效去除。热力学计算结果表明,当钢中w(T[O])为0.0010%、w([Mg])大于0.00018%时,脱氧产物Al_(2)O_(3)热力学上就不能稳定存在。铝脱氧、高碱度渣精炼条件下很难稳定地获得固态Al_(2)O_(3)夹杂物。为获得完全固态尖晶石或高熔点钙铝酸盐夹杂物,钢中w([Ca])需控制在0.0001%以内。钢中w([Ca])大于0.0002%,就具备生成液态夹杂物的热力学条件。
Composition,type and quantity of inclusions in bearing steel during LF refining and RH vacuum treatment were studied.The experimental results were analyzed and discussed in combination with thermodynamic calculation and interface parameters between inclusions and liquid steel.The inclusion analysis results showed that the deoxidization product Al_(2)O_(3)disappeared after 25 min refining,and the inclusions in steel were mainly pure spinel,spinel containing small amount of CaO,CaO·2 Al_(2)O_(3)and CaO·Al_(2)O_(3).Pure spinel,spinel containing small amount of CaO,CaO·2 Al_(2)O_(3)and CaO·Al_(2)O_(3)were still the main inclusions in steel after 65 min refining to the end of LF refining.After RH vacuum treatment for 25 min,the total number of inclusions in steel was reduced by 75%compared with that after LF refining.The removal efficiency of pure spinel and spinel containing small amount of CaO inclusions was 99.5%and 93.2%,respectively,and that of CaO·2 Al_(2)O_(3)inclusion was 67%.The inclusions after RH treatment were mainly liquid calcium aluminate CaO·Al_(2)O_(3)and 12 CaO·7 Al_(2)O_(3).The size of spinel inclusions in the refining process was concentrated below 10μm,and the inclusions above 20μm were mainly calcium aluminates in the liquid phase,which had appeared in the early stage of LF refining.Solid inclusions pure spinel,spinel containing small amount of CaO and CaO·2 Al_(2)O_(3)whose contact angle with molten steel was greater than 90°were easy to remove in RH vacuum treatment,while liquid inclusions CaO·Al_(2)O_(3)and 12 CaO·7 Al_(2)O_(3)whose contact angle with molten steel was less than 90°were not easy to remove.Therefore,controlling the inclusions into solid inclusions after LF refining was beneficial to the high efficient removal of inclusions in RH vacuum treatment.The thermodynamic calculation results show that when the w(T[O])is 0.0010%and w([Mg])in steel exceeds 0.00018%,the deoxidization product Al_(2)O_(3)cannot be stable in thermodynamics.It is difficult to obtain solid Al_(2)O_
作者
王昆鹏
王郢
徐建飞
陈廷军
谢伟
姜敏
WANG Kun-peng;WANG Ying;XU Jian-fei;CHEN Ting-jun;XIE Wei;JIANG Min(Technology Center,Zenith Steel Group Co.,Ltd.,Changzhou 213011,Jiangsu,China;Zenith Special Steel Co.,Ltd.,Changzhou 213011,Jiangsu,China;School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Bejing 100083,China)
出处
《钢铁》
CAS
CSCD
北大核心
2022年第6期42-49,共8页
Iron and Steel
关键词
轴承钢
精炼
真空处理
固态夹杂物
接触角
热力学
去除率
bearing steel
refining
vacuum treatment
solid inclusion
contact angle
thermodynamic
removal rate
