120t LF精炼渣系对弹簧钢55SiCrA夹杂物塑性的影响

Effect of 120t LF Refining Slag System on Plasticity Inclusions in 55SiCrA Spring Steel

在分析"120 t LD→LF→RH→150 mm×150 mm连铸坯→线材轧制"工艺流程生产的弹簧钢55SiCrA的基础上,应用Factsage热力学计算软件进行热力学计算,对精炼工艺进行优化研究。结果表明:精炼渣系中含SiO_(2)41%~46%、CaO 36%~41%、Al_(2)O_(3)0%~3%、MgO 10%,渣碱度0.8~1.0,可使CaO-SiO_(2)-Al_(2)O_(3)系夹杂物成为塑性夹杂物。使用低Ti、低Al合金及无铝耐材,冶炼终点[Al]降至0.0018%~0.0022%,[Ti]降至0.0010%~0.0012%,钢中铝镁尖晶石和Ti N等不变形夹杂物明显降低,夹杂物中Al_(2)O_(3)含量降至15%左右,夹杂物成分全部位于低熔点区。

Based on the analysis of 55 SiCrA spring steel produced by"120t LD→LF→RH→150 mm×150 mm continuous casting billet→wire rolling"process,the thermodynamic calculation is carried out by using Factage thermodynamic calculation software to optimize the refining process.The results show that the inclusions in CaO-SiO_(2)-Al_(2)O_(3) system can be transformed into plastic inclusions with the content of SiO_(2)41%~46%,CaO 36%~41%,Al_(2)O_(3)0%~3%,MgO 10%refining slag and slag basicity 0.8~1.0.Using low Ti,Al alloy and non-aluminum refractory material,the smelting end[Al]reduces to 0.0018%~0.0022%,[Ti]reduces to 0.0010%~0.0012%,the undeformed inclusions such as aluminum magnesium spinel and TiN in the steel are obviously reduced,the content of Al_(2)O_(3) in the inclusions is reduced to about 15%.The inclusion ingredient are all located in the low melting point region.