Effect of different micro-plasma arc welding (MPAW) processes on the corrosion of AISI 316L SS tubes in LiBr and H3PO4 solutions under flowing conditions

This work studies the corrosion under flowing conditions of four kinds of AISI 316L materials welded by the micro-plasma arc welding technique in different media: a basic (LiBr) and an acidic (H3PO4) solution by means of polarization measurements. Sensitization tests, galvanic corrosion evaluation, microstructural analyses and microhardness tests have been also carried out. Corrosion parameters revealed that, among the materials welded with backing gas, the alloy which presented better corrosion behaviour was the one welded without filler alloy. However, this kind of material could undergo several corrosion problems if a crack is formed or due to an inadequate joint penetration.