邢钢400系低碳易切削不锈钢控碳工艺实践

Process Practice on Carbon Control of Low Carbon 400 Series Free Cutting Stainless Steel at Xingtai Steel

430F、430FR等低碳易切削不锈钢成品碳含量≤0.035%,由于邢钢采用60 t AOD-LF-CC的低成本生产工艺,其中经常采用造价昂贵的低碳合金和增加末期脱碳时间来保证产品碳合格率,相比同系列的低碳430铁素体不锈钢,吨钢成本升高达100元。通过提高AOD脱碳温度和调整过程碱度,实现出钢[C]≤0.015%。在出钢和精炼工序采用镁钙材质渣线代替镁碳材质渣线的钢包,并调整精炼炉渣氧化性,实现精炼过程平均增碳量≤0.007%。低碳易切削不锈钢整体成品碳含量合格率由76%提高到了≥92%,实现AOD-LF-CC工艺连续生产低碳430系列易切削不锈钢。

The carbon content of low carbon free-cutting stainless steels such as 430 F and 430 FR is≤0.035%.Because Xingtai Steel adopts the 60 t AOD-LF-CC low-cost production process,it is by using expensive low-carbon alloys and increasing terminal decarburization time to ensure product carbon qualified rate.Compared with the same series of low-carbon 430 ferritic stainless steel,the cost per ton of steel rises by 100 yuan.By increasing AOD liquid decarburization temperature and adjusting process basicity to realize tapping [C]≤0.015%.In the tapping and refining process,the magnesia-calcium slag line ladle is used to replace the magnesium-carbon slag line ladle,and the oxidizability of the refined slag is adjusted to achieve an average carbon increase of≤0.007% in the refining process,and the qualified rate of the carbon content of the low-carbon free-cutting stainless steel is increased from 76% to over 92%,to realize the continuously produces low carbon 430 series free cutting stainless steel by AOD-LF-CC process.