Wuxi Dongao Nonferrous Casting Co., Ltd.
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The shrinkage analysis of casting properties of pump castings
- Nov 09, 2017 -


Under normal circumstances, if the carbon equivalent is same, the increase of Si/C ratio will increase the formation tendency of ferrite. However, for the small castings such as the pump castings, even the Si/C ratio increases, the tendency of ferrite appears in the tissue is not large, so it will not affect its strength.
Therefore, the shrinkage of casting performance of pump casting mainly includes three aspects, and one is the linear shrinkage. From the perspective of actual work, the higher the temperature formed by the solid skeleton of the metal liquid, the earlier the line shrinkage and the longer the shrinkage of the product will be. So the value of the linear shrinkage will become larger. In this way, when the carbon equivalent is same, the increase of Si/C ratio will increase the number of primary austenite, and the solid skeleton will be formed earlier, thereby increasing the linear shrinkage.
However, according to the actual production situation, the difference is not obvious, and the effect of pump casting linear shrinkage is small, so in practice, there is no waste products. The second aspect, the shrinkage of casting performance of pump casting also includes volume shrinkage.
In the traditional process of cast iron and high Si/C ratio cast iron, although the carbon content is less, the carbon equivalent is slightly higher. So there is no obvious difference in the volume shrinkage of this cast iron. This feature has also been verified in actual production.
The last aspect is the section sensitivity. In comparison, the section sensitivity of high Si /C is obviously lower than that of cast iron. Because of this characteristic, it is very important for the submersible pump castings which often need to bear the impact force.