Hardfacing is the application of a hard, wear-resistance material to the surface of a component by welding, spraying, or allied welding processes in order to reduce wear or loss of material by abrasion, impact, erosion, galling, and cavitation (1). Many alloys have been developed for their unique hardfacing capabilities. Prominent among these are the cobalt and nickel base alloys. These alloys are available in a variety of forms: wire, bar, sheet, and powder. In order for these alloys to adhere properly to the matrix material, the surface tension of that material must be overcome.
One means of accomplishing this is to create a small molten pool which melts the alloying material and a small fraction of the matrix. Such a technique minimizes dilution but still allows good metallurgical bonding. A continuous wave laser of sufficient power density can be used to create such a shallow molten pool and by dropping powder in front of the laser beam, a hardfacing surface results.
Several investigations of hardfacing using continuous wave laser have been reported (2-10). The purpose of this investigation was to determine the effectiveness of utilizing a high power, continuous wave, carbon dioxide laser as a heat source for the deposition of a variety of commercially available hardfacing powders. The effectiveness of the process was determined by measuring the amount of dilution, the amount of powder deposited, the hardness of the deposits, and the microstructure of the deposits.