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Thermal expansion of industrial aluminum castings

Sep. 04, 2019

Thermal expansion of industrial aluminum castings

When aluminum casting and alloy are heated, generally speaking, the volume has to expand (that is, the geometric size has to extend), known as thermal expansion. The linear expansion coefficient is commonly used. For example, in the Aluminum Casting design of precision instruments and precision machine tools, in order to maintain their high accuracy, it is required to use the precision alloy with very small linear expansion coefficient to manufacture. In the use of different metals made of a part, such as dissimilar metal welding, will consider whether their thermal expansion is close, otherwise it will be due to the expansion of different parts deformation or damage. The property of a metal to conduct magnetism is usually called magnetism.

Such as iron, nickel, cobalt and so on all have high magnetic conductivity (called magnetic metal), is the manufacture of motor and communication equipment in the indispensable materials. On the contrary, some of the aluminum castings by China Cast Aluminum Part supplier in machinery are required to be non-magnetic, such as the guard ring on the motor. Metals in general conduct heat, or heat conductivity. When the metal parts are heated or cooled, due to the different temperatures (temperature difference) on the surface and inside of the parts, and thus the expansion is different, a kind of internal stress will be generated inside the metal. If the internal stress is greater than the strength of the metal, cracks will occur inside the metal.

Aluminum Furniture (Correct Spelling)

Aluminum Furniture (Correct Spelling)

The worse the heat conductivity of the metal, the greater the temperature difference between the inside and outside, correspondingly, the greater the internal stress, the metal parts in heating or cooling, it is easy to crack. In addition, good thermal conductivity, parts easy to heat. Copper and aluminum alloys conduct heat well and are often used to make components such as radiators and heat exchangers.

Industrial aluminum Casting Foundry product corrosion loss:

Both aluminum castings and alloys conduct current, called conductivity. Silver conducts electricity best, followed by copper and aluminum, so copper and aluminum and their alloys are commonly used in industry as conducting structural materials. Alloys that do not conduct well (i.e. have a high resistance) are sometimes needed, such as those used to make parts such as heating elements.

Generally, metal parts are eroded by oxygen and water vapor in the air, and some equipment is corroded by acid and alkali. It can be seen that the corrosion resistance of aluminum casting refers to the ability of metal to resist the erosion of various media. It is estimated that the annual loss of metal due to corrosion of aluminum castings in industry is about 1% of the total production, which is a huge waste and loss.

Therefore, it is necessary to fight against corrosion and improve the corrosion resistance of metal, which has practical economic significance for saving metal consumption and prolonging the service life of metal materials. Many equipment in modern industry, such as various industrial boilers, thermal processing machinery, steam turbines, jet engines, rockets, missiles, etc., have many parts that work at high temperatures. These parts of the material required to have good oxidation resistance, or the surface will be quickly oxidation peeling and damage. These parts must be made of heat resistant material.

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