CW617N | CuZn40Pb2 Dezincification on ball valve shut-off valve

The ball valve from a tap water system failed after 3 years due to dezincification. The dezincification depth is about 350µm. According to the water analysis, the hard tap water should be uncritical for the alloy; the combined acid capacity and chloride concentration are safely in the uncritical zone of the Turner Diagram. A dezincification test acc. to DIN EN ISO 6509-1, on the other hand, led to 200 to 1300 µm dezincification depth. Established machining brass with axially aligned alpha-beta microstructure and a hardness of 147 HV0.5.