Stellite 6 is a widely applied hardfacing alloy with good corrosion and wear resistance. Several different techniques have been used to deposit this alloy, like oxyacetylene, Tungsten Inert Gas welding overlay, CO 2 laser cladding and thermal spray methods. This paper evaluates the wear and corrosion resistance of Stellite 6 coatings applied by high velocity oxygen fuel (HVOF) spraying and gas tungsten arc welding (GTAW) hot wire technique. Mechanical properties and microstructural characteristics of the coatings are assessed and compared. The influence of these properties in the wear results is further discussed.

The purpose of this study is to determine if a GTAW (TIG) repair weld under an APS ceramic coating would cause a reduction in adhesion strength. Two stainless steels and a titanium alloy were selected for the study. For each material, 300 buttons were machined and further processed in groups of 50 through the application of one-pass, three-pass, or full pad welds. Welded buttons were lapped parallel to within 0.0002 in. and their lengths were compared with measurements obtained from buttons that had not been welded. NiCrMo bond coats were applied by HVOF spraying to both welded and unwelded samples, which were then top-coated with a ceramic layer (Cr 2 O 3 , Cr 2 O 3 -Al 2 O 3 , or TiO 2 ) deposited by air plasma spraying. A ten-cycle heat treatment was conducted on half of the samples to determine if the weld would amplify thermal expansion stresses. Based on adhesion test results, the welding had no measurable effect on adhesion strength nor did the heat treatment. Heat input from the HVOF flame and the plasma jet was sufficient to reduce weld-related solidification stresses.