One of the most important product forms of ULTIMET® alloy is welding wire, since many applications involve ULTIMET® weld overlays. These overlays are, of course, subject to dilution from the substrate material, often a steel or stainless steel. To provide some idea of the influence of dilution upon the corrosion resistance of ULTIMET® weld overlays, a study was undertaken whereby pre-diluted consumables were made by the aspiration casting process, and all-weld-metal (AWM) samples made by deposition on chilled copper blocks. Thus, it was possible to conduct regular (rather than one-sided) corrosion tests in acid solutions on homogeneous samples, diluted with specific substrate materials.