RH脱硫对无取向电工钢中夹杂物的影响

Effect of RH desulphurization on inclusions in non-oriented electrical steel

研究了RH脱硫对常规工艺(连铸+热轧)和CSP工艺下的无取向电工钢热轧材样中夹杂物的影响。两种工艺下,当CaO-CaF_2脱硫剂加入量为1～4 kg/t时,RH脱硫率约为25%。终渣氧化性高、曼内斯曼指数(MI)低是影响脱硫效果的原因之一。CSP产线RH采用"先铝后硅"的脱氧方式,热轧材样中夹杂物主要是AlN、MnS、CaS和少量铝酸钙。此时,夹杂物总量主要受氮含量影响,硫含量只与硫化物夹杂密度呈正比关系。常规产线RH采用"先硅后铝"脱氧方式,热轧材样中氧化物夹杂和AlN夹杂含量相当,含钙夹杂物数量只占夹杂物总量的12%左右。脱硫剂中CaF_2对耐材的侵蚀导致RH脱硫时热轧材样中含Mg夹杂数量是不脱硫时的2倍。

The effect of RH desulphurization on inclusions in non-oriented electrical steel through conventional process(continuous casting + hot rolling) and CSP process has been studied in this paper. When the amount of CaO-CaF2 desulfurizer is 1-4 kg/t, the RH desulfurization rate is about 25 %. The high oxidation of final slag and low MI value are one of the reasons for the desulfurization effect. The RH of CSP process is deoxidized by 'aluminium followed by silicon'. The inclusions are mainly AlN, MnS, CaS and a small amount of calcium aluminate. At this time, the total amount of inclusions is mainly affected by nitrogen content, and the sulfur content is proportional to the density of sulfide inclusions. The RH of conventional process is deoxidized by 'silicon followed by aluminium'. The content of oxide inclusions and AlN inclusions in the sample is equal, and the amount of Ca inclusions only accounts for about 12 % of the total inclusions. The corrosion of CaF2 from desulfurizer to refractories results in the amount of Mg inclusions in RH desulfurization sample twice as much as that in non-desulfurization.