Aluminium casting

About two-thirds of all aluminium castings are used in the automotive industry, e.g. in ears, buses, lorries, trains and aireraft. The need to reduee vehicle fuel consumption and weight has inereased the interest in aluminium. The total mass of aluminiiun in a European car roughly doubled between 1990 and 2000. This growing use of aluminium in its major user sector elearly has an effeet on the overall number of eastings produeed. 

Aluminium is mainly east into permanent moulds. The relative shares of applied casting 

For holding, electric furnaces have the advantage of not producing burner off-gases and being able to sustain a homogeneous temperature over the whole molten volume, at a relatively low energy expense. 

Aluminium melting in foundries generally uses alloyed ingots as a starting material, although in some cases the metal is delivered already as a liquid. The secondary melting of aluminium scrap is usually not performed in foundries and falls outside the scope of this document. It is discussed in the BAT reference document for the non-ferrous metals industries. 

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The aluminium casting alloys are mostly based on the Al-Si system (phase diagram Fig. A1.31). It is a classic eutectic system, with a eutectic point at about 11% Si and... 

Figure A1.53 shows the aluminium-silicon system, basis of most aluminium casting alloys. 

Private communication from A. P. Fenn, Esq., Birmingham Aluminium Casting (1903) Co. Ltd. 

Aluminium cast onto steel or cast iron is used to produce integral aluminium/steel drums and bimetallic pistons. Aluminium clad onto other metals by mechanical bonding is used in heat-exchanger systems subject to multiple atmospheres or environments. The clad products are also used for cooking utensils and functional press work. 

Any cavity of a form suitable for producing a desired shape in an elastomer, the mould may be of any material (plaster, ebonite, aluminium, cast iron, steel) of strength suitable to the means employed in moulding the product. 

M.J. Couper et al Casting defects and the fatigue behaviour of an aluminium casting alloy. Fatigue Fract. Eng. Mat. Struct. 13, 213-227 (1990)... 

The examples of small aluminium castings here dealt with will chiefly appeal to tlie home vorker or small-business man who only occasionally requires to cast in this metal. 

Cleaning and Finishing Aluminium Castings.—iSpK ial cleiuiing or pickling of aluminium castings is -seldom neiH s-sary, as they come from the mould quite white. 

Light metal and aluminium casting Bentonite Cereal binder ... 

Magnesimn-alloyed-aluminium casting Bentonite Boric acid... 

Table 3.43 Comparative data for residue production from Lost Foam and green sand aluminium casting...

Table 3.53 shows input-output data for the slide grinding of aluminium castings. The effluent water goes to a water treatment system and is re-circulated into the slide grinding equipment. Abrasive rocks are used and come out unaltered, besides for some minimal wearing. 

Table 3.53 Input-output balance for the slide grinding of aluminium castings [177, Silva Ribeiro, 2002]...

Adequate degassing with physically operating treatment processes does not achieve sufficient cleaning in most aluminium castings. Vacuiun degassing achieves a very low hydrogen content in the melt but, at the same time, the lower munber of nuclei means that crystallisation is less effective. 

This technique applies to the serial production of small and medium sized products in ferrous and non-ferrous metal. Maximum casting sizes are 1000 x 1000 x 550 mm. The technique finds most of its implementation in aluminium foundries and has a 2 % share of aluminium casting. 

Foundry details aluminium castings, 5500 tonne/yr production good castings, 6864 tonne/yr production molten metal ... 

Zalensas, D. L. (1993). "Aluminium Castings Technology, 2nd ed.", American Foundrymen Society. 

Structure and Basic Mechanical Properties of Aluminium Casting Alloys... 

Fig. 3.1-36 Ranges of tensile strength for some important aluminium casting alloys [ 1.9]...

E. Nachtigall, G. Lang Electrical conductivity of aluminium castings, Mitt. Verein. Metallwerke Ranshofen-Berndorf, 16-19 (in German) (1965)... 

Ceramic foam filters are widely used for the filtration of A1 alloys from oxide films, and they also purify A1 from gases and intermetallic inclusions due to their big surface area. Usually, they have the shape of torque bricks with a height of 50 mm and sides of 200 mm, 230 mm, 325 mm, 400 mm, 525 mm, and 585 mm, but sometimes they have a cylindrical shape. The filtration box may be with or without preheating. The main characteristic of ceramic foam filters is the number of pores per inch (ppi). Filters with 20, 30, 40, 50, and 60 ppi are used in aluminium cast houses. The most common are filters with 30 and 40 ppi. Filters with 60 ppi are used for the filtration of special alloys. 

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