Why can brass impellers withstand cavitation?
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This post was last edited by wwn10 on 2015-10-16 at 14:41. As the title suggests, there are many methods to prevent cavitation, and one of them is to use impellers made of brass; this approach is used in the condensate pumps of many power plants. Question: Why can brass impellers withstand cavitation? Is it more resilient?
I’ve never heard of using brass impellers, but I have heard of using phosphor bronze ones. When trying to prevent cavitation by changing the material of the flow-through components, it usually relates to parameters such as the hardness of the material. This material is more resistant to cavitation, but the structure and performance curve of the pump remain unchanged.
Condensate pump, produced by Changsha Pump Factory, model 4N6×2A; the material of the first impeller is silicon brass 80-3, while the second impeller is made of cast iron HT20-40CuMo；
In my opinion, whether it is brass or stainless steel or other corrosion-resistant materials, the reason lies in the higher surface finish of these materials compared to gray cast iron. The smoother the surface of the impeller’s flow channels, the better the strength and toughness of the material, as well as its hardness and chemical stability. Consequently, the centrifugal pump’s resistance to cavitation increases. I have also seen brass impellers repaired from cavitation using copper wire~~