Influence of argon pollution on the weld surface morphology

In this paper the surfaces of butt welded joints in steel tubes were analyzed using an optical
3D measurement system to determine the morphology and topographic parameters. It
was established that pollution of the argon shield gas with oxygen did not influence the
width of the heat-affected zone. However, the composition of the shield gas significantly
influenced the surface asymmetry, Ssk, and its inclination Sku. The measurement of these
parameters enabled the selection of a higher quality surface, which was visually proven
by the reduction in discoloration of the surface of the weld joint. High quality surfaces
eliminate a potential habitat for bacteria and a future source of corrosion as well as providing
less resistance to fluid flow.