The 0. 17~0.23C-≤0. 15Mo steel 20G for high pressure boiler is melted by a 92 t UHP EBT EAF-LF process at Chengdu Iron and Steel

Pan Steel Group. The operation practice showed that 35% pig iron in charge for arc furnace

adding 3~10 mm carbon particle and stengthening supply oxygen to form 500~750 mm foaming slag were available to remove partial nitrogen in molten steel

as a consequence the average nitrogen in steel came to 45×10-⁶ at arc furnace tapping. During LF refining

the operation of large amount slag embedding arc

weak argon stiring and cutting-down heating time was adopted to control the increment of nitrogen in steel no more than 10×10-⁶ in refining period.The nitrogen content in steel after refining in LF was(60~66)×10-⁶

that was efficiently to prevent aged brittleness of steel products.