Abstract: The present paper introduced the practice of duplux process in two converters in Sansteel Minguang Co., Ltd., Fujian for 65 steel production. And Dephosphorization and decarburization process parameters and application results were discussed. The process parameters in dephosphorization furnace were blowing oxygen intensity 2.0~2.7 m³/(t•min), blowing time 7~10 min, average lime charge 33.3 kg/t, average basicity 1.51, bottom stirring gas intensity 0.25 m³/(t•min) and end-point temperature 1330~1351℃. The semi-steel average phosphorus mass fraction could be decreased to 0.028 4 % and average carbon mass fraction was 3.04 %. The average dephosphorization degree was 67.7 %. Less slag blowing and catching carbon were used in decarburization furnace with the process parameters of oxygen intensity 4.0 m³/(t•min), bottom stirring gas intensity 0.13 m³/(t•min), average lime charge 13.8 kg/t. At the endpoint of blowing, the average phosphorus mass fraction was 0.013 %, the average carbon mass fraction was 0.21 %, which realized tapping at low phosphorus and high carbon contents. Smelting reduction process with manganese ore was realized in decarburization furnace and manganese ore charge was 4~6 kg/t. The average manganese recovery rate of 46.3 %, and under the catching carbon process the average manganese mass fraction was 0.303 % at the endpoint. The application of high carbon steel production with duplex process in two converters realized the tapping at low phosphorus high carbon contents and manganese ore smelting reduction, and expected blowing results had been obtained.

Key words: De-P furnace, De-C furnace, dephosphorization process, high carbon steel smelting, duplux process in two converters