Abstract: 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 x 10^-6, using low titanium deoxidizer and alloying materials in LF refining process to control LF end [Ti] ≤30 x 10_6, VD treatment for 27 min, controlling tundish liquid superheating extent 20 ~30 ℃ and whole course shielding casting, the <1>500 - 800 mm concasting bloom of S355NL steel for wind power flange (/% : 0. 14 ~ 0. 15C, 0. 21 ~ 0. 23Si, L 30 ~ 1. 33Mn, 0.03 ~ 0. 04Nb, ≤0.003Ti, 0.04 ~ 0. 05V, ≤0. 010P, ≤003S, 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%.

摘要： 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%。

关键词: 风电法兰用钢S355NL, Φ500-800 mm连铸坯 , -50℃冲击功, 冶金质量