汽车零部件用45Mn2R硫系易切削钢的开发

采用≥40%铁水-50 t EAF-LF-VD-180 mm×220 mm铸坯-轧制流程开发了45Mn2R钢Φ40~50 mm轧材。通过控制EAF终点[C]≥0.10%,[P]≤0.015%,出钢温度1620~1660℃,出钢过程用“增碳剂+复合脱氧剂(15%Ca-12%Al-45%Si)+合成渣(50%CaO-34%Al_(2)O_(3)-4%MgO)”预脱氧,Ca处理前钢水S含量≤0.010%,Ca处理20 min后喂S线,VD后软吹25~30 min等工艺措施,提升钢的纯净度和可浇性。结果表明,生产的45Mn2R钢(/%:0.43~0.46C,0.22~0.27Si,0.009~0.017P,0.065~0.086S,0.32~0.36Cr,0.003~0.010Ti,0.013~0.034Als)具有良好的综合性能,各项指标满足用户要求。