X80管线钢CaS形成机理研究

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%,wCaT0.001 7%~0.002 7%就可以生成液态钙铝酸盐,此时当钢液中wS0.001 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.

Study of CaS Formation Mechanism in X80 Pipeline Steel

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 w_CaT>0.001 7%~0.002 7% when w_AlT in X80 pipeline steel is 0.03%~0.06%, and Ca and S can form CaS by direct reaction when w_S>0.001 8%~0.002 8% correspondingly. The modification degree of Al₂O₃ inclusions has a great effect on the generation of CaS. With the increase of the S content in molten steel, the possibility of CaS formation at the edge of inclusion will increase. The agreement between thermodynamic calculation and actual production is proved by industrial test. Two kinds of CaS with different forming modes were found, and thus the rationality of predicted generating modes of CaS was proved.