钙处理车轮钢洁净度

Cleanliness of calcium-treated wheel steel

为了解钙处理对车轮钢洁净度的影响，对BOF-LF精炼．RH精炼一钙处理．CC工艺生产车轮钢系统取样，采用扫描电镜对试样中夹杂物的形貌、尺寸及组成进行了分析。研究表明，钙处理前夹杂物主要为Al2O3-CaO及少量的MgO和SiO2，尺寸在5μm以内，钙处理后夹杂物主要为A12O3-CaO-CaS，在板卷中呈不连续簇条状，部分尺寸为10pm以上；RH·中间包一热轧过程1～5μm夹杂数量密度呈降低趋势，由10降至3．1个／mm^2，5～10／am夹杂数量密度控制在1个／mm^2以内，10pm以上夹杂数量密度控制在0．2个／ram2以内；铸坯w（T[O]）控制在0．0010％以内；对夹杂物进行面扫，板卷中主要夹杂物为CaS-CaO-Al2O2夹杂以及CaO-A12O3-MgO；对夹杂物$LN过程变形分析得出，轧制过程变形的长条状夹杂成分为CaO-Al2Q3而未变形的夹杂成分CaO-A12O3外包裹CaS。

Calcium treatment to the cleanliness of wheel steel was studied, Wheel steel produced through the process of BOF, LF refining treatment, RH refining treatment, calcium treatment and continuous casting was sampled systemati- cally. The morphology, size and composition of inclusions were analyzed by scanning electron microscopy （SEM） equipped with energy dispersive X-ray spectrometer （EDS）. The results show that the composition of inclusions are A120^-CaO with a small amount of MgO and SiO2 before calcium treatment. The size of these inclusions is within 5 μm. After calcium treatment, the inclusions are mainly Al2O3-CaO-CaS, with the morphology of discontinuous clusters in the coil. Some of these inclusions are larger than 10 μm. The number density of inclusions with the size of 1 to 5 μm de- ceases from 10 to 3.1/mm2 from RH, tundish to hot roiling. The number density of inclusions ranging from 5 to 10 μm in size is less than 1/mm^2. The number density of inclusions larger than 10 μm is less than 0.2/mm：. The w（T[O]） of slab is less than 0.001 0%. The element mapping analysis of inclusions shows that the inclusions in coil are mainly CaS-CaO- A12O3 and CaO- AI203-MgO. The change in the morphology of inclusions in the rolling process is analyzed. The deformed inclusions after the rolling are CaO-A1203, while The non-deformable inclusions are CaO-A1203 wrapped with CaS.