Degassing melts during solidification in a mould - using gas bubbles and baffle-plate to circulate melt in feeder head

摘要

Process for the degassing of a melt which is solidifying in a mould, the novelty being that the degassing occurs in the feeder head, into which a current of scrubbing-gas bubbles is fed so that increased circulation occurs between the melt in the feeder and the remainder of the melt which is still solidifying in the mould to form the casting. The feeder head pref. contains a baffle plate with the gas inlet(s) on one side, causing the melt to circulate and flow downwards into the mould, and the top part of the feeder head is pref. heated. Instead of a baffle plate, a tube projecting down into the mould may be used to create the desired circulation of the melt. During solidification, dissolved gases, e.g. H2 in molten iron, are transferred to the molten part of the metal in the mould and the riser. The invention removes such gases by scrubbing in the feeder, and the process is suitable e.g. with large castings.