100 t EAF-LF-VD-CC流程生产SK5弹簧钢的工艺实践

SK5 弹簧钢(/% ：0. 75 ~0. 84C, ≤0. 35Si, ≤0. 40Mn, ≤0. 035P,≤0.030S)经 100 t EAF-LF-VD-CC 流程生产。通过EAF出钢加硅镒合金和铝铁进行预脱氧,LF精炼过程添加80~150 kg铝镁钙和少量硅锭合金进行复合铝脱氧，精炼渣碱度11.13,(CaO)/(Al₂O₃) =4. 98等工艺措施，脱氧效果较明显，铸坯中平均全氧含量达到 11 x 10^-6项,铸坯中氮含量达到35 x 10^-6。冶炼过程夹杂物种类按纯Al2O3＞硫化物一'MgO - A12O3 - CaO—MgO •Al₂O₃ • CaO • SiO₂变化,铸坯中夹杂物主要为CaO-A1₂O₃ • SiO₂ - MgO系,其塑性化程度可通过调整精炼渣成分、降低精炼渣熔点实现进一步优化。

Practice of Process for Spring Steel SK5 Produced by 100 t EAF-LF-VD-CC Flowsheet

The spring steel SK5 (/% : 0.75 ~0. 84C,≤ 0. 35Si, ≤0.40Mn, ≤0. 035P, ≤0.030S) is produced by 100 t EAF-LF-VD-CC flow sheet. With using the process measures including pre-deoxidizing at EAF tapping by adding silicon-manganese and ferroaluminium, compound-deoxi dizing during LF refining process by adding 80 ~ 150 kg aluminium- manganese-calcium alloy and small amount silicon manganese alloy with refining slag basicity 11.13 and ( CaO) / ( Al₂ 0₃) =4. 98, the deoxidizing effect is obvious, the average total oxygen content is 11 X 10^-6 in casting billet and the nitrogen content in billet is 35 x 10 ^-6. During steelmaking process the change sequence of inclusions in steel is pure A1₂O₃- sulfide- MgO  •A1₂O₃ • CaO- MgO • A1₂O₃ • CaO • SiO₂, and the main inclusions in billet is CaO • Al₂ O₃・ SiO₂ ・ MgO series, its plasticization level could be optimized future by adjusting refining ingredient and reducing melting point of refining slag.