Preparation of sand casting material for aluminum alloy cabin door with overall wall thickness of 2 mm

There is no aluminum alloy brand equivalent to d357 alloy in sand casting aluminum alloy materials in China, and the close brand is ZL114A. The comparison of chemical composition between the two is listed in the table.

It can be seen from the table that d357 alloy has very high requirements for Mg content control, which needs to be controlled within the fluctuation range of 0.05; D357 alloy has strict requirements for impurity element content. There is no specific requirement for single impurity content in Chinese ZL114A alloy, but d357 alloy must be less than 0.05. In terms of total impurity requirements, ZL114A alloy is five times that of d357 alloy.

In order to melt d357 alloy, on the one hand, the purity of raw materials should be ensured during sand casting smelting. On the other hand, the one-step smelting process of low-temperature silicon addition, refining, refining and modification should be adopted to reduce the smelting temperature, reduce alloy suction and oxidation slag, and improve the purity of alloy liquid. In addition, the technology of high-purity argon rotary injection and flux compound refining is adopted for refining. By using the rotary shear effect of the nozzle, the highly dispersed argon bubbles are evenly dispersed in the alloy liquid and float up, and the slag and gas suction are attached to the interface between aluminum and flux and absorbed by flux to improve the refining effect. In production, the method of pre furnace analysis is used to detect the magnesium content. According to the test results, the molten solution is supplemented with magnesium. This method solves the problem of magnesium content control. The alloy element composition and impurity content in d357 alloy melted by the above measures are within the specified range of the standard.