X80管线钢CaS形成机理研究

Study of CaS Formation Mechanism in X80 Pipeline Steel

通过热力学计算,研究了Ca-Al,Al-S,Ca-S平衡关系.以Ca-Al,Al-S两个平衡为参考,在固定S含量的基础上,建立了液态钙铝酸盐区域分布图.结果表明:对X80管线钢wAlT=0.03%~0.06%,wCaT>0.001 7%~0.002 7%就可以生成液态钙铝酸盐,此时当钢液中wS>0.001 8%~0.002 8%即可有Ca与S直接反应生成CaS;Al2O3夹杂物变性程度对CaS的生成与否影响很大;随钢液中S含量的增加,钙铝酸盐夹杂物边缘生成CaS的可能性增加.通过工业实验,证明了热力学计算结果与实际生产符合得很好.找到了以不同方式形成的两种CaS,从而证明了预测CaS生成方式的合理性.

The equilibrium relationships of Ca-Al, Al-S and Ca-S were determined by thermodynamic calculation. The regional distribution of calcium aluminates was established on the basis of fixed sulfur content with the relationship of Ca-Al and Al-S as reference. The results indicate that liquid calcium aluminates can be generated with wCaT 0. 001 7% ~ 0. 002 7% when wAlTin X80 pipeline steel is 0. 03% ~ 0. 06%,and Ca and S can form Ca S by direct reaction when wS 0. 001 8% ~ 0. 002 8% correspondingly. The modification degree of Al2O3 inclusions has a great effect on the generation of Ca S. With the increase of the S content in molten steel,the possibility of Ca S formation at the edge of inclusion will increase. The agreement between thermodynamic calculation and actual production is proved by industrial test. Two kinds of Ca S with different forming modes were found,and thus the rationality of predicted generating modes of Ca S was proved.