100t EAF-LF-VD-CCM流程S355NL风电法兰用钢Φ500~800mm连铸坯的研制

Development and Production of Φ500~800 mm Concasting Bloom of S355NL Steel for Wind Power Flange by 100 t EAF-LF-VD-CCM Flow Sheet

通过电弧炉兑60%铁水,大量换渣操作,使用低钛合金控制电弧炉终点[Ti]≤7×10^(-6),LF精炼采用低钛脱氧合金化材料,控制LF终点[Ti]≤30×10^(-6),VD 27 min处理,控制中间包钢水过热度20~30℃全程保护浇铸等工艺措施,成功试生产出S355NL风电法兰用钢Φ500~800 mm连铸坯(/%:0.14~0.15C,0.21~0.23Si,1.30~1.33Mn,0.03~0.04Nb,≤0.003Ti,0.04~0.05V,≤0.010P,≤0.003S,0.02~0.04Alt)。检验结果表明,该钢锻件的综合机械性能良好,-50℃冲击功为87.4~100.3 J,用户产品无损探伤合格率达99.5%。

With the process measures including arc furnace charging 60%hot metal,changing large amount of slag operation,using low titanium alloy to control arc furnace end[Ti]≤7×l0^-6,using low titanium deoxidizer and alloying materials in LF refining process to control LF end[Ti]≤30 ×10^-6,VD treatment for 27 min,controlling tundish liquid superheating extent 20 ~30 ℃ and whole course shielding casting,the Φ500 ~800 mm concasting bloom of S355 NL steel for wind power flange（/%：0.14~0.15 C,0.21 ~0.23 Si,1.30 ~ 1.33 Mn,0.03~0.04 Nb,≤0.003 Ti,0.04~0.05 V,≤0.010 P,≤0.003 S,0.02 ~0.04Alt） has been successfully pilot-produced.The examination results show that the comprehensive mechanical properties of steel are better,the impact energy at-50 ℃ is 87.4 ~ 100.3 J,and user products nondestructive testing qualified rate is up to 99.5%.