Liquid surface suspension pressurization control method for low-pressure casting machine

Abstract

The invention relates to low pressure casting technology, especially relates to a suspending pressing device of low pressure casting machine. The method is: a. affirms the initial value; confirms the pressure P correspondent to the height h0 of suspending level; b. storing: the P is stored in programmable logic controller as the base value; c. sets the compensating value: works out the pressure compensating coefficient delta H between the two times of pours, then works out the pressure compensating quantity delta P, and memorizes the value; d. carries on unloading control: after unloading, the pressure in pot is equal to sum of the initial P and the nth compensating quantity delta P. the invention can reduces cost, and upgrades the producing efficiency.

Description

technical field [0001] The invention relates to low-pressure casting technology, in particular to a liquid surface suspension pressurization device for a low-pressure casting machine. Background technique [0002] The gating system used in low-pressure casting is to move the liquid metal in the molten pool, that is, the crucible, from bottom to top through the riser under pressure to fill the mold. [0003] The molten metal in the crucible needs to be kept at a high temperature for 2 to 7 hours. During this period, it may go through nearly a hundred times of pressurization and exhausting. The fluctuation of the liquid level caused by this will produce quite thick oxides on the liquid surface. The long-distance ups and downs of the liquid metal in the riser will cause strong disturbances, bringing the oxides on the liquid surface to the bottom of the crucible, and causing the coatings on the inner and outer walls of some risers to be washed and peeled off. When filling the m...

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Problems solved by technology

[0003] The molten metal in the crucible needs to be kept at a high temperature for 2 to 7 hours. During this period, it may go through nearly a hundred times of pressurization and exhausting. The fluctuation of the liquid level caused by this will produce quite thick oxides on the liquid surface. The long-distance ups and downs of the liquid metal in the riser will cause strong disturbances, bringing the oxides on the liquid surface to the bottom of the crucible, and causing the coatings on the inner and outer walls of some risers to be washed and peeled off. When filling the mold, it is brought into the cavity, causing oxidation inclusions and coating inclusions in the casting, which affects the internal quality of the casting; at the same time, this large-distance lifting and falling will cause severe erosion to the riser tube and reduce the riser. tube life

[0004] For the pressurized device that does not require metal liquid surface suspension, the cost is relatively high because it consumes a large amount of compressed air, especially for those low-pressure castings that must use inert gas as the medium, the cost is higher, so that Affect its value in actual use

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