| 摘要 |
PURPOSE:To prevent clogging and abnormal erosion of a nozzle and to stabilize casting operation by making neighborhood of an inner hole in the nozzle two or more layers of multi-layers structure and forming the nozzle with the specific compositions of high CaO component layer in the inner hole surface side and low CaO component layer in the base material side. CONSTITUTION:In the nozzle for pouring the molten metal into a tundish or a mold, the neighborhood of inner hole 4 in the nozzle is made to two or more layers of multi-layers structure. and the inner hole surface side is formed with the high CaO component layer 2 composed of 15-30wt.% Cab, 40-80% ZrO2, 5-40% graphite and <10% the other refractory component and the base material 7 side is formed with the low CaO component layer 1 composed of '<=17% Cab, 40-80% ZrO2, 5-40% graphite and <10% the other refractory component. That is, in working face side of inner hole in the nozzle, Al2O3 is made to low m.p. and melted and removed, and preventing effect of Al2O3 stickness to the nozzle is improved and further, in the inner side of the nozzle, the preventing effect of Al2O3 stickness is low, but by setting material having small erosion quantity, the abnormal erosion can be prevented. |
