轴承钢精炼中大型夹杂物来源的示踪

 为了控制轴承钢中大型夹杂物，采用在LF精炼初渣中添加示踪剂的方法， 确定轴承钢大型夹杂物的来源。 初期脱氧夹杂一直悬浮在钢中，未与炉渣接触，不含BaO成分，在钢中残留量占全部氧化物夹杂的10%～15%；内生夹杂由渣钢反应生成，随精炼进行，含BaO夹杂的比例升高。无渣冶炼如RH可抑制该类夹杂生成，在钢中残留量约占25%～40%；卷渣夹杂由钢渣搅动生成，绝大多数含有BaO成分，随精炼进行尺寸逐渐减小，残留在钢中的比例约占50%～60%。因此，降低钢中大型夹杂物的技术措施是严格控制脱氧前钢水的氧活度aO，]降低w(TO])；]尽可能避免或减弱渣钢反应强度，或降低精炼渣的还原势；优化钢水搅拌强度，减少卷渣并促进微细夹杂物聚合上浮。

Generation mechanism of large inclusions during bearing steels refining process by tracer method

The generation mechanism of large size non-metallic inclusions has been studied by the method of adding tracer agent into the refining slag during Ladle Refining process. The results show that the large size inclusions in the high carbon chromium bearing steels mainly originate from primary de-oxidation reaction,intrinsic reaction and refin-ing slag mixing. The three type inclusions occupy 10%-15% of all the oxides,25%-40% and 50%-60% respectively. The primary de-oxidation inclusions linger in liquid metal without contact with the slag,therefore their contents have no BaO. The intrinsic reaction inclusions originate from interface reaction between steel and slag,and the BaO content of the inclusions increases with the refining process going on. By the refining process without slag,such as RH process, the formation of inner formed inclusions can be hold back. The slag-mixing inclusions originate from liquid steel stir-ring and most of them have some BaO. The size of the inclusions decreases with the refining process going on. There-fore,the methods for decreasing the number of large size inclusions are as follows,confining strictly the oxygen activi-ty,a0,before deoxidizing process,decreasing w(TO]) in liquid metal,weakening and even avoiding slag-metal inter-face reactions and decreasing the reduction potential ability of slag as possible,and optimizing the liquid metal stirring intensity to decrease the slag involving and promote the tiny inclusions coagulating and floating upwards and being ab-sorbed by the refining slag.