喂钙量与软吹氩对316L不锈钢中夹杂物的影响

Effect of Calcium Addition Amount and Soft Argon Blowing on Inclusions in 316L Stainless Steel

采用20 t电弧炉-AOD-LF-铸锭的生产工艺制备316L不锈钢,并通过LF钙处理与底吹氩的方法降低钢中夹杂物含量。其中喂钙量通过经验参数与热力学计算相结合的方法确定。运用金相显微镜及扫描电子显微镜分析了LF钙处理比例系数(实际喂Ca量/理论喂Ca量)1.65和2.95及喂Ca后软吹时间对钢锭中非金属夹杂物组成、分布及尺寸的影响。结果表明,316L不锈钢钙处理比例系数约为2.95,钙处理后钢液中夹杂物主要为铝酸钙类化合物和硅酸盐类化合物;延长软吹时间对于大尺寸夹杂物的去除效果显著;在0~25 min,随着软吹时间的延长,钢锭中夹杂物的数量减少,平均尺寸减小,最优的软吹时间为20 min。

316L stainless steel is prepared by the production process of 20 t EAF-AOD-LF-casting ingots,and the inclusion content in steel is reduced by LF calcium treatment and bottom argon blowing.The calcium addition amount is determined by a combination of empirical parameters and thermodynamic calculations.The metallographic microscope and scanning electron microscope are used to analyze the effect of ratio coefficient(actual feeding Ca amount/theory feeding Ca amount)1.65 and 2.95 and soft blowing time after LF feeding Ca on ingredient,distribution and size of non-metallic inclusions in steel ingots.The results show that the reasonable ratio coefficient of 316L stainless steel after calcium treatment is about 2.95.The inclusions in the molten steel after calcium treatment are mainly calcium aluminate compounds and silicate compounds.Extending the soft blowing time had a significant effect on the removal of large-size inclusions;within 0~25 min,the quantity and average size of inclusions in the steel ingot reduced with extending soft blowing time and the optimal soft blowing time is 20 min.