20CrMnTiH齿轮钢中非金属夹杂物演变行为  

Formation and evolution of non-metallic inclusions in 20CrMnTiH gear steel during LF-RH-CC process

作　　者：王章印 陈亮[1] 陈雄 李平凡 Wang Zhangyin;Chen Liang;Chen Xiong;Li Pingfan(Panzhihua Iron and Steel Research Institute Co.,Ltd.,Pangang Group,Panzhihua 617000,Sichuan,China;Panzhihua Steel and Vanadium Co.,Ltd.,Pangang Group,Panzhihua 617000,Sichuan,China)

机构地区：[1]攀钢集团攀枝花钢铁研究院有限公司,四川攀枝花617000 [2]攀钢集团攀枝花钢钒有限公司,四川攀枝花617000

出　　处：《钢铁钒钛》2024年第3期155-161,共7页Iron Steel Vanadium Titanium

摘　　要：通过工业试验分析了20CrMnTiH在精炼过程中非金属夹杂物的演变行为,并采用FactSage8.0热力学软件计算了20CrMnTiH在钙处理、二次氧化和冷却凝固过程中夹杂物的转变趋势。结果表明,LF精炼过程中夹杂物由Al_(2)O_(3)向MgO-Al_(2)O_(3)和CaO-MgO-Al_(2)O_(3)转变,经过钙处理后,夹杂物改性为CaO-MgO-Al_(2)O_(3)和CaO-Al_(2)O_(3)-CaS,随后经过RH真空精炼,在真空精炼结束时进行第二次钙处理,夹杂物转变为高CaS含量的CaO-Al_(2)O_(3)-CaS和CaO-MgO-Al_(2)O_(3),连铸过程中钢液发生再氧化,夹杂物中CaS含量进一步升高。热力学计算表明,在钢液中加入0.003%~0.000 5%的[Ca]时,钢液中会生成高熔点的MgO-Al_(2)O_(3),当[Ca]的加入量在0.000 5%~0.000 7%时,夹杂物主要为液态夹杂物,当[Ca]含量大于0.000 7%时,钢液中开始有CaS生成。此外,二次氧化的发生会使得钢液中的液态夹杂物更多地转变为固态夹杂物。随着温度的降低,夹杂物中CaO、CaS含量在逐渐降低,而MgO、Al_(2)O_(3)含量逐渐增加,最终形成高CaS含量的CaS-CaO-MgO-Al_(2)O_(3)。The formation and evolution of non-metallic inclusions in 20CrMnTiH gear steel during LF-RH-CC process were analyzed by industrial trials,and the transformation trend of non-metallic inclusions during reoxidation and cooling solidification in 20CrMnTiH gear steel was analyzed by thermodynamic calculations.During LF refining,inclusions experience evolutions from Al_(2)O_(3) to MgO-Al_(2)O_(3) and CaO-MgO-Al_(2)O_(3).After calcium treatment,inclusions are modified into CaO-MgO-Al_(2)O_(3) and CaO-Al_(2)O_(3)-CaS.After calcium treatment at the end of RH vacuum refining,inclusions are modified into CaO-Al_(2)O_(3)-CaS with high CaS contents and CaO-MgO-Al_(2)O_(3).During continuous casting,the content of CaS in inclusions increase with the reoxidation of steel.Thermodynamic calculations reveal that when 0.0003%to 0.0005%[Ca]is added to the steel,MgO-Al_(2)O_(3) would be formed in the steel.When 0.0005%to 0.0007%[Ca]is added to the steel,liquid calcium aluminates would be largely formed.When the content of[Ca]exceeds 0.0007%,CaS would be formed.Moreover,liquid inclusions would be gradually transformed into solid inclusions with the reoxidation of steel.With the decrease of temperature,the contents of CaO and CaS in inclusions decrease and the contents of MgO and Al_(2)O_(3) in inclusions increase,leading to the formation of CaS-CaO-MgO-Al_(2)O_(3) with high CaS contents eventually.

关 键 词：20CrMnTiH 夹杂物 钙处理 二次氧化 

分 类 号：TF704.7[冶金工程—钢铁冶金]