Aluminum Leakage from Inner Hole of Hot Top Casting Aluminum Alloy Hollow Ingot and Its Improvement Method
With hot top casting aluminum alloy hollow ingot,due to the thin crystalline shell on the inner hole surface,crack is easily occurred on the shell under the action of force and even leak the molten alloy.Through microscopic observation,it is found that there are stretch marks and cracks in the ingot where the molten liquid is leaken,and sud-den leakage often occurs.Combined with the actual production,the causes of tensile leakage and non-tensile leakage in hollow aluminum alloy ingot were analyzed.It is pointed out that some measures should be taken from the structure of casting mould,casting parameters and operation technology to avoid molten alloy liquid leakage.The thickness and ten-sion of the inner cavity shell are controlled by achieving a thermal balance between the heat release of aluminum alloy melt and heat absorption of cooling water during semi-continuous casting.The non-tensile leakage is mainly caused by excessive pressure in the cavity of cast pipe.Therefore,a casting mold equipped with an internal hole exhaust device was developed,and measures were taken to optimize the casting temperature,casting speed,cooling speed and cool-ing uniformity.The production reveals that the gas pressure in the mold cast pipe is effectively reduced by using the internal hole exhaust device,and the non-tensile leakage is eliminated,while other measures can well control the thick-ness of crystalline shell to avoid tensile leakage.
Aluminum Alloy Hollow IngotHot Top CastingCrackStress
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