| 摘要 |
1302065 Casting composite ingots INLAND STEEL CO 11 Feb 1970 [27 Feb 1969] 6521/70 Heading B3F [Also in Division C7] Surface checking during hot rolling of machineable and extrudable steels containing Te and/or Se is reduced by filling at least most of an ingot mould with the steel free from Te and Se, allowing a skin to form at least on the sides of the ingot mould while maintaining the core molten, introducing the Te and/or Se from the top into the molten core and dispersing it therein and then allowing the core to solidify to a totally solid ingot with a skin devoid of substantial amounts of Te or Se around a core containing machinability enhancing amounts of Te and/or Se; and then hot rolling the ingot. Rimming steels are cast into an ingot mould at 1580-1593‹ C. and allowed to rim to form a solid skin. Te may be added in shot pellet or bar form downwardly into the molten core of the cast ingot, the rimming action stirring the Te into the steel. After extraction from the mould the ingot is reheated to 1100-1150‹ C. and conventionally hot-rolled to form billets. Non- rimming steels are cast into an ingot mould until the mould is 85-90% full and the cast ingot allowed to cool until a solid skin has been formed. Te is added by completing pouring with a steel jet into which is introduced Te. Alternatively, the ingot mould is completely filled with steel, allowed to cool to form an ingot skin and Te mechanically propelled into the ingot core and the ingot core stirred, by introducing gas into the ingot or mechanically. |
