| 摘要 |
PURPOSE:To extend the lifetime of a sprue part and improve the operability and safety by a method wherein the material of the sprue and a stopper which close the sprue contains a basic mud material including C and SiO2 of a particular ratio, and a sprue lining material. CONSTITUTION:An opening 20 is composed of a sprue part 21 which penetrates through a lining iron shell to the inside of a furnace, a sprue lining 22 which is lined thick on the internal surface of the furnace around the sprue, and a mud material 23 which is filled in the sprue 21. In comparison with conventional mud, the mud material 22 contains lower SiO2 and C components, 5 - 10% of SiO2 and 5 - 10% of C, and higher MgO component. As such blended mud material 23 is used, gas blowing during molten metal discharging is reduced, and the sealing characteristic of the mud material 23 is improved because of a high melting point of the mud material 23. Further, the length of the sprue part becomes longer as the thickness of the furnace wall around the sprue is thick, so that the filling amount of the mud material 23 increases, and the chargeability is increase. |
