92 t EAF-LF冶炼20G钢液的氮含量控制

Control of Nitrogen Content in Molten Steel 20G Melted by a 92 t EAF-LF Process

攀成钢公司采用92 t EBT(偏心底)UHP EAF-LF(钢包炉)工艺冶炼成分(%)为0.17～0.23C-≤0.15Mo的高压锅炉钢20G.操作实践表明,在EAF(电弧炉)炉料中配加35%的生铁,并通过添加3～10 mm的碳粒和强化供氧,形成500～750 mm的泡沫渣,以利去除钢液中的部分氮,使EAF出钢时钢中氮含量平均达到45×10-6.LF精炼时采用大渣量埋弧操作,氩气弱搅拌和缩短加热时间,以便控制精炼时钢液增氮量不超过10×10-6,并使LF精炼后钢中氮含量达(60～66)×10-6,有效地防止钢材产生时效脆性.

The 0.17～0.23C-≤0.15Mo steel 20G for high pressure boiler is melted by a 92t 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 strengthening 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 stirring 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.