Surface topography of pulsed current gas metal arc clads

Abstract

Clad surface quality in the pulsed current gas metal arc welding (GMAW-P) process is mainly influenced by the pulse parameters. Selection of the most suitable combination of pulse parameters is very difficult owing to the complex interdependence of the parameters on the pulsed current. Therefore the effect of pulse parameters on clad surface characteristics has been studied for different types of droplet detachments, namely background detachment, one droplet detachment per peak, two droplet detachments per peak, and three droplet detachments per peak. The most suitable type of droplet detachment for cladding, using a 1·2 mm diameter ER 5356 filler metal, has been selected on the basis of measuring the surface characteristics of the clad using a computerised measuring system based on a linear variable differential transformer. One droplet detachment per peak was considered to be capable of providing a smoother clad surface than the other types of droplet detachment. The peak energy was found to be low for the background detachment.