Evaluation of nozzle geometries for laser surface alloying

Abstract

Five general types of nozzles and nine configurations were tested in a water tunnel and using gas pressure analysis to determine their effectiveness at reducing entrained air from the outside environment during laser surface alloying. Two orientations with regard to the work piece were employed: The optics and nozzle being normal, the optics and nozzle being at a 15° oblique angle. Both argon and nitrogen were studied. In the impingement region, they produced roughly the same results regardless of the nozzle configuration. The change in orientation of the nozzle, however, had an effect. For 0° orientation the 7° simple nozzle with shroud is best and at 15° orientation the conic nozzle is the best when used in the reverse processing direction. A shroud surrounding the nozzles had minimal influence on the reduction of oxygen (approximately 1%) at normal and oblique incidence. The impingement region of the gas was found to be adequate in size for all of the cases.