Repairing Casting Defects by High Pressure Cold Spraying Method
The objective of this study was to investigate whether high pressure cold spray can be used to repair casting defects. The experiment conducted involved microstructural observations and mechanical property measurements of 316L stainless steel powder (20-44μ) cold sprayed coatings deposited onto a cast CA6NM martensitic stainless-steel substrate. The substrate was cold sprayed by hand using a VRC GEN III Cold Spray System with Nitrogen as the carrier gas. Substrate holes with different sizes and preparation techniques were created to mimic casting porosity. The backside of the plate was machined smooth and cold spray filled to perform ASTM C633 adhesion testing. Microstructural studies revealed cracks and improper bonding at the coating-substrate interface in many of the filled holes.