Now with die casting alloys for die casting, the process and very mature, widely, but in 6 series and pure aluminum die casting are rarely the promotion of large area, and batch production, this process only in advanced technology, personnel to improve the specification of the company, pure aluminum die casting is not difficult to do, now in the application and specific requirements on all kinds of heat sink, you would think easily stick mold die casting production process.Now our factory has several experiences to discuss with you:
In order to conduct pure aluminum die-casting, the difference between properties of pure aluminum and die-casting aluminum materials should be distinguished first:
Properties of pure aluminum and aluminum alloy
Density: aluminum is a very light metal with a density of 2.72 g/cm 3, about one-third that of pure copper.
Conductive thermal conductivity, thermal conductivity and electrical conductivity of aluminum is good, when the aluminum section and length and the copper phase at the same time, about 61% of the copper aluminum conductive ability, if the same weight of aluminum and copper and the cross section of different length (equal) aluminum conductive ability for copper 200%.
Chemical properties: good atmosphere decay resistance, because its surface is easy to form a dense alumina membrane, can prevent the internal metal into one step oxidation, aluminum and nitric acid, organic acid and food had little reaction.
Aluminum is face-centered cubic structure, industrial pure aluminum ent (bits = 80%), it is easy to take a variety of molding process, but it was low, the sigma b is about 69 mpa, therefore, only by cold deformation strengthening or pure aluminum alloying to increase its strength, can only be as structural materials;Aluminum is non-magnetic, non-spark material, and has good reflection performance, which can reflect both visible light and ultraviolet light.The impurities in aluminum are silicon and iron. The higher the impurities, the lower the conductivity, corrosion resistance and plasticity.
2. Aluminum alloy if add the right amount of certain alloying elements in aluminum, after cold working or heat treatment, can significantly improve certain features, commonly used in the aluminum alloy elements for copper, magnesium, silicon, manganese, zinc, these elements are sometimes join alone, sometimes cooperate in, in addition to the above elements, sometimes adding trace amounts of titanium, boron, chromium, etc.
According to the composition and production process characteristics of aluminum alloy, it can be divided into casting aluminum alloy and deformation aluminum alloy.
Deformation aluminium alloy: this kind of aluminum alloy pressure usually by hot or cold processing, namely after rolling, extrusion process, such as sheet, pipe, bar and various materials used, this kind of alloy with high plasticity, so the content of the alloy is less.Casting of aluminium alloy is pouring liquid metal directly in sand mold, made from a variety of complex shape parts, for this kind of alloy has excellent castability, namely good liquidity, alloy content, suitable for deformation aluminium alloy, alloy content, do the casting aluminium alloy.The elastic modulus of aluminum alloy is small, only about a third of the steel, namely under the same cross section, to the same load, the elastic deformation of aluminium alloy is 3 times of steel, the strength is not strong, but the seismic performance is good.The hardness range of aluminum alloy (including annealing and aging hardening) is 20~120HB.The hardest aluminum alloy is softer than steel.The tensile strength limit of aluminum alloy is 90Mpa(pure aluminum) to 600Mpa(super hard aluminum), which is quite different from steel.
The low melting point of aluminum alloy (generally at about 600 ℃, steel at 1450 ℃ or so).
Aluminum alloy has excellent plasticity at room temperature and high temperature, and can be formed into structural parts with extremely complex section shape, thin wall and high dimensional precision by extrusion.In addition to suitable mechanical properties, aluminum alloy also has excellent corrosion resistance, thermal conductivity and polishing properties.