Porosity is a common term used by both casting customers and suppliers when the topic is casting defects. Precision brass components manufacturers will explain this defect in detail in this post. You must read this post whole to know about porosity.
Porosity term is often used to explain any hole or void found on the surface of a casting. To define the specific defect, determine its cause, and analyzing the extent to which it will affect the properties of the castings, morphology of pores is critical. There are cases in which the existence of porosity will not be detrimental to the function of casting.
When you understand the several porosity-type defects, casting designing becomes easier thing. Manufacturers can fix some defects during production process, while other defects can be fixed by changing the design or a combination of both options. By understanding the factors of casting that contribute to the distinct defects, you can simply work with the casting supplier to prevent potential issues. You can relocate porosity-prone areas and prepare mutually accepted levels of porosity present.
Identify and Quantify
When you discover a defect in a provided casting, you can tell the supplier three things- type of defect, the surface area where it is exist, and the quantity or frequency of its occurrence.
Gas or shrinkage
Most of the times it is the gas formation that forms porosity in the casting. However, shrinkage and non-metallic compound formation are next reasons to porosity.
Large gas-related voids occur when mold is trapped or core gases are trapped in the molten metal. This trapped gas forms blowholes. Blowholes are usually large enough to look like bubbles with smooth surface (interior). Pinholes are formed in castings when gas atoms are dissolved in molten metal. They stay small, but float at top of the surface in the casting.
Manufacturers need to find the reason behind gas formation as it will help them to fix the source of gas and prevent porosity in casting.
Shrinkage defects can be prevented by making changes in casting geometry. Manufacturers can change the location of thin and thick sections for instance.
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