Grey Cast Iron has been the first choice of material used in housings and gear boxes from medium to large sizes, because it is easier for foundry production than Ductile Iron.
Other reasons include:
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Structural rigidity
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High strength by compression standards
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Strength to weight ratio
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High ability to be machined
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Corrosion resistant
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Excellent casting ability for detailed and complex shapes
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Sound absorbing
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Lower costs and high availability of the necessary raw materials
You may have heard someone referring to grey cast iron as grade GG20, or grade GG15, or whatever grade it may be. Grey cast iron is given different grades depending on the chemical composition of the iron. The composition of the iron can be altered in different ways depending on the application in which the iron is going to be used. Some castings may be required to withstand immense pressure while others may not be under any pressure at all. For example, grey cast irons in grades GG15 to GG20 are most frequently used as a housing material. This is due to housings typically being under great pressure, and in the Germany standard DIN 1691, grade GG20 chemical composition is designed to withstand a yield strength of 200 Mpa.
Grey Iron Sand Casting Gearbox |
