Dye penetrant test on
bronze casting can be done to detect the surface porosity, surface shrinkage,
hot tear and cold shuts. The porosity is
formed when the gas bubble cannot escape through risers and some trapped inside
(cannot be detected by dye penetration test) and some trapped in the surface
and is detected by this test.
The fluorescent dye penetration test normally is used in the production line for bronze and other light alloy castings. This point should be taken into account that in this test the indication looks very bigger than its real size.
Similarly, this test cannot reveal internal shrinkage in the bronze casting, but if the shrinkage is open to the surface, then examination will reveal it. Shrinkage happens when the cooling is not consistent with the different locations of the object. It means one point is colder than other point during the solidification process.
The test is done in casting to see if any of these happened during the casting process. The hot tear might happen by inconsistent cooling of the thick and thin area, and cold shut happens when the bronze material solidifies before even melted.
The Type penetrant test on bronze material might perform as periodic inspection of material such as in the valve bodies, vertical pump bowl to detect any crack that might happen in service. The test should be performed based on approved test procedure and with qualified Level II inspector.
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