Effect of root pass filler metal on microstructure and mechanicalproperties in the multi-pass welding of duplex stainless steels

Auteurs :  Ahmed KELLAI, Azzedine Lounis, Sami KAHLA, Brahim IDIR
Année : 2018
Domaine : Métallurgie
Type : Article de journal
Revue : The International Journal of Advanced Manufacturing Technology
Résumé en PDF :  (résumé en pdf)
Fulltext en PDF :  (.pdf)
Mots clés : Gas tungsten arc welding (GTAW), duplex stainless steel, Root pass, Filler metal, Microstructure and mechanical properties

Résumé : 

This paper is focused on the estimation of the effect of root pass chemical composition, in multi-pass GTA Weldments, onmicrostructure and mechanical properties of duplex stainless steel welds.We used two different fillermetals, the super duplex ER2594 and duplex ER 2209. Microstructures of different passes of welded joints are investigated using optical microscope andscanning electron microscope. The relationship between mechanical properties, corrosion resistance, and microstructure ofwelded joints is evaluated. It is found that the tensile and toughness properties of the first weldment, employing the combinationof ER 2594 in the root pass and ER 2209 in the remaining, are better than that of the second weldment employing ER 2209 allpasses, due to the root pass grains refinement and its alloy elements content as chromium Cr and nitrogen N. The microstructureindicates the presence of austenite in different forms on the weld zone of ER 2209, same in the case of ER 2594, but with highercontent and finer grains size, in particularWidmanstätten austeniteWA. Potentiodynamic polarization tests of the first weld metalevaluated in 3.5% NaCl solution at room temperature have been demonstrated a corrosion resistance higher than that of thesecond weld metal. This work addressed the improvement of the corrosion resistance using appropriate filler metal withoutgetting any structural heterogeneity and detrimental changes in the mechanical properties.