| 摘要 |
<p>PURPOSE:To manufacture cast iron at a low cost from melting materials of poor quality by starting oxygen blowing into the molten metal when the temperature of the molten metal reaches the prescribed value, and stopping the oxygen blowing when the temperature of the molten metal reaches the prescribed value or exceeds it. CONSTITUTION:Melting materials such as scrap, return scrap, pig iron and ductile pig iron are charged into an arc furnace. Electric charging is started and the treatment of melting, heating, oxygen blowing after melt down, slag off, and iron tapping is executed, followed by the simple ladle refining to manufacture the cast iron. Oxygen is blown into the molten metal when the temperature of the molten metal reaches 1420 deg.C at the time of heating and temperature rise of the arc furnace, the molten metal is boiled and stirred in the exothermic reaction of CO gas to make the nitride in the molten metal afloat. When the temperature of the molten metal exceeds 1500 deg.C, the oxygen blowing is stopped, and the supply of oxygen and electric charging are stopped. Then, the slag is removed, the molten metal is transferred to a simple lade refining furnace to adjust the contents and execute the refining. This constitution prevents the gas defects and chilling tendency caused by the high content of nitrogen.</p> |
