Abstract: The extent of modification of Al₂O₃ inclusion and factor of CaS inclusion formation in refining liquid of steel 20CrMnTiHl after calcium treatment have been studied by thermodynamics equilibrium calculation between liquid steel and inclusions. Calculated results show that with calcium treatment of liquid steel containing 0. 020% ~ 0. 035% [S] and 0. 02% 〜0. 04% [ Al] , the stable CaS forms easily and the aluminum deoxidizing product Al₂0₃ is not easily modified to low-melting calcium aluminate 12( CaO) ,7( Al₂0₃). In order to completely modify the Al₂O₃ to low-melting calcium aluminate (CaO) • ( Al₂0₃ ) and 12( CaO) *7( Al₂O₃) , in refining process the calcium treatment of liquid steel should carry out in conditions of low [S] and ≥1 600℃ , and the sulfur wire feeding operation carries out after soft argon stirring, it is available to obviously decrease the occurrence of nozzle blocking.

Key words: Gear Steel 20CrMnTiHl Containing Sulfur, Calcium Treatment, Thermodynamics, Control of Inclusion Modification

摘要： 通过钢液与夹杂物之间的热力学平衡计算,研究了20CrMnTiH1精炼钢水中Al₂O₃夹杂物钙处理后可能变性的程度和CaS夹杂生成条件。计算结果表明,[S]0.020%～0.035%、[Al]0.02%～0.04%的钢水进行钙处理时易生成稳定的CaS,并且铝脱氧的产物Al₂O₃难以完全变性成低熔点钙铝酸盐12(CaO)·7(Al2O3)。为使Al₂O₃完全变性成低熔点(CaO)·(Al₂O₃)和12(CaO)·7(Al₂O₃)钙铝酸盐,在精炼过程应在低[S]和温度≥1600℃情况下对钢水进行钙处理,软吹氩搅拌后进行喂硫线操作,同时可以显著减少水口堵塞的发生。

关键词: 20CrMnTiH1, 含硫齿轮钢, 钙处理, 热力学, 夹杂物变性控制