Process of Sand Casting Aluminum Alloy Billet

Abstract

A novel process for sand casting of aluminium alloy casting blanks relates to the technical field of aluminium alloy casting. In casting sand, a certain amount of particle metal shots are added, and the metal shots and the casting sand are at the proportion of (1-5): (3-7). Metal has a relatively big coefficient of thermal transmission, after a cavity is filled with an aluminium alloy solution, the cast surfaces are sequentially solidified under the chilling action of the casting sand containing the metal shots; as the solidification speed of the cast surfaces is high, dendrites have no time in growing up, only fine and compact crystal structures are obtained; the thinner the crystal grain of casts is, the dispersed the secondary phase, the shrinkage porosity and the gas pores between crystal axes become, and even, no casting defects exist. As the metal shots are low in manufacturing cost and can be used repeatedly, high cost in manufacturing an all-metal die is reduced, the manufacturing cost is lowered and the economic benefits are improved.

Description

technical field [0001] The invention relates to the technical field of aluminum alloy casting, in particular to a process for sand-casting an aluminum alloy billet, and is particularly suitable for casting an aluminum alloy mold billet for a refrigerator inner tank. Background technique [0002] The inner liner of the refrigerator is mostly made of ABS or HIPS, and the surface finish after molding is very high, which requires the surface finish of the mold to be also very high. The material of the liner mold is aluminum alloy, and the casting blank of the mold adopts the method of sand casting. The heat transfer coefficient of the sand casting blank of the casting aluminum alloy mold is small, and the air permeability is poor. Long, so the metal alloy is easy to form coarse grains and shrinkage during the solidification process, which determines to a certain extent that shrinkage cavities, pores and pinholes are easy to appear on the surface of the casting after machining, a...

AI Technical Summary

Problems solved by technology

[0002] The inner liner of the refrigerator is mostly made of ABS or HIPS, and the surface finish after molding is very high, which requires the surface finish of the mold to be also very high. The material of the liner mold is aluminum alloy, and the casting blank of the mold adopts the method of sand casting. The heat transfer coefficient of the sand casting blank of the casting aluminum alloy mold is small, and the air permeability is poor. Long, so the metal alloy is easy to form coarse grains and shrinkage during the solidification process, which determines to a certain extent that shrinkage cavities, pores and pinholes are easy to appear on the surface of the casting after machining, and trachoma and sticky sand are easy to occur on the surface of the casting. Therefore, the yield of sand casting liner mold is low

[0003] In order to refine the coarse grain structure inside the casting and eliminate the casting defects on the surface of the casting, the all-metal casting process can be used to cast the mold, but the manufacturing cost of the full-metal mold is high, the production preparation period is long, and the processing of the metal mold is time-consuming and laborious. It is relatively difficult to produce large-scale castings. difficulty

Metal mold casting is especially suitable for large batches of small and medium-sized castings, while refrigerator liner molds are generally produced in a single piece, without batch parts, and the castings are large in size, so using metal molds to produce molds can meet the mold surface quality requirements, but production High cost and long cycle

In terms of economic cost and technical difficulty, the all-metal process is not suitable for the manufacture of liner mold blanks

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