| 摘要 |
<p>PURPOSE:To obtain metal of high refining accuracy by adding heating in a vacuum induction melting furnace or slag refining wherein the flow passage of the molten metal maintained at a specified temp. is changed to a series of stages. CONSTITUTION:In the stage of performing a series of stages of heating, melting, refining, tapping and casting of metal by the use of a vacuum induction melting furnace, degassing of O, H, N, etc. from the inside of molten metal and decarburization are accelerated by vacuum refining after heating and melting. Thereafter a flux for removing impurities or for adsorption of inclusions is charged for the purpose of dephosphorization, desiliconization, etc. into a molten metal, whereby slag refining is accomplished. Here, the molten metal is heated or is held at a specified temp.; at the same time the induced agitating flow is changed to the flow that ascends over the entire area on the furnace wall 3 side and descends in the central part of the furnace. Thus the molten metal is agitated thoroughly and the flux 2 is accumulated in the recess 4 formed in the central part on the surface of the molten metal 1, whereby the contact thereof with the wall 3 is prevented and the slag refining is accomplished. After the removal of the slag, the molten metal is subjected to vacuum finish refining in the same furnace.</p> |
