Spray and Fuse

The spray and fuse method is by far the most commonly used technique for hard surfacing. It is a method by which powdered metal alloys are forced through an oxyacetylene gun-type torch. The powder is melted and the propelled in a molten state at the part's surface.

  • Yields an instant solidification and a mechanical bond between the coating and substrate. The coating is then fused to the substrate to obtain a permanent molecular bond.
  • Normally recommended for new and not salvaged, worn parts because of the high temperatures attained in the fusing process (1,900°F to 2,200°F) may cause warpage.
  • Is more economical to apply than rod-welded or plasma coatings because of the application's rapidity and the coating's controllable thickness.
  • Has its limitations with coating thicknesses. Overlays up to 1/16" (0.0625") can be applied without extreme difficulty. But thicknesses greater than 1/16" require special attention and, generally, a higher cost.