L360QS钢钙处理的热力学分析与试验研究

Experiment research and thermodynamics analysis on calcium treatment of pipeline steel L360QS

针对管线钢L360QS，利用活度相互作用系数和Bjorkvall方法对钙处理过程进行热力学分析，并对管线钢进行了实验室的钙处理试验和工业试验。热力学分析结果表明，当钢中a（Als）=0．045％时，如果要生成12CaO·7Al2O3夹杂且避免GaS夹杂析出，则应控制钢液中a（Ca）在33．21×10^-6左右，a（s）〈0．002563％。钙处理试验表明，GaS夹杂数量随着钢液中钙含量的增加而增多，且含MgO·Al2O3尖晶石的夹杂物有所减少。为使氧化夹杂和硫化夹杂变性完全，应控制钢液中w（S）≈0．002％，w（Ca）=0．0035％～0．0040％，且w（T.Ca）／w（S）〉1．90工业试验结果表明夹杂物变性良好，达到预期效果。

Thermodynamics analysis on calcium treatment process of pipeline steel L360QS was investigated by activity interaction coefficient and Bjorkvall method, and then calcium treatment experiment was also carried out. Thermodynamics analysis result showed that,when aluminum content in liquid steel was 0. 045 %,w（Ca） and w（S） in molten steel should be respectively controlled about 0.003 321% and below 0. 002 563 % if you wanted to generate 12CaO·7Al2O3inclusions and to avoid precipitation of CaS inclusions; calcium treatment experiment result demonstrated that CaS inclusions quantity increased with the increasement of calcium content in liquid steel, which decreased the inclusions containing spinel. In order to modify both oxide and sulphide inlusions completely,w（S） in molten steel should be controlled about 0. 002 %, and w（Ca）should be in the range of 0. 003 5 % - 0. 004 0 % ,as well as the w（T. Ca）/ w（S） should be above 1.9. Industrial results showed that the inclusions were modified, which achieved the desired effect completely.