Abstract: The production process flowsheet of steel 508III for nuclear power welding (/% ：0.09~0.12C, 0.30~0.40Si, 1.45〜1.65Mn, ≤0.008P, ≤0.008S. 0.45~0.60Mo, 0.60~0.75Ni) is 20t EAF-LF-VD-4t ingot-forged to 150 mm x 150 mm billet-rolled to Φ5.5 mm coil. With process measures including using quality charge, high basicity slag and high FeO content, and controlling liquid temperature 1550 ~ 1570 °C , the EAF end [P] is ≤0.002% , and using low phosphorus alloys, the phosphorus content in steel is ≤0.006% ； in LF refining process using silicon-calcium alloy for killing and SiC powder for diffusion deoxidation, and using CaO-Al₂O₃-SiO₂ slag series with basicity 5.0~5.5, in VD process vacuum ≤67 Pa and Ar flow rate 30~50 L/min, and shielding casting etc measures the analysis results of 3 heats steel show that the gas content in steel is 1.3 x 10^-6~1.5 x 10^-6 [H] , 10 x10^-6~14 x 10^-6[ 0] and 44 x 10^-6~58 x 10^-6 [N] to meet the cleanliness requirement of steel 508Ⅲ for nuclear power wielding.

Key words: 20t EAF-LF-VD-ingol casting process, Steel 508III, Slag Series, Deoxidation Process, Vacuum Degassing, Cleanliness

摘要： 核电焊材用钢508 Ⅲ（/%:0.09~0.12C,0.30~0.40Si,1.45~1.65Mn,≤0.008P,≤0.008S,0.45~0.60Mo,0.60~0.75Ni）的生产工艺流程为20t EAF-LF-VD-4t铸锭-锻造150 mm×150 mm坯-轧制Φ5.5mm盘条。采用精选炉料,以及高碱度渣、高FeO含量,钢水温度1550~1570℃等措施控制,电弧炉终点[P]≤0.002%,并选用低磷合金,使钢中磷含量≤0.006%;LF采用硅钙合金沉淀脱氧,SiC粉扩散脱氧、CaO-Al₂O₃-SiO₂渣系,碱度5.0~5.5,VD真空度≤67Pa,Ar流量30~50 L/min,保护浇铸等措施后,3炉钢的分析结果表明,钢中气体含量为1.3×10^-6~1.5×10^-6[H],10×10^-6~14×10^-6[O]和44×10^-6~58×10^-6[N],满足核电焊材用钢508Ⅲ洁净度的要求。

关键词: 20t EAF-LF-VD-铸锭工艺, 508Ⅲ钢, 渣系, 脱氧工艺, 真空脱气, 洁净度