Corrosion characterization in superduplex stainless steel cladding

ABSTRACT Superduplex stainless steels have a dual structure constituted approximately by 50% of ferrite and 50 % of austenite. This fact produces a good combination of mechanical properties and corrosion resistance. Thanks to these features their use is growing, mainly in the industries of paper, chemical, gas and oil. Surfacing welding is used for the manufacture and / or repair of parts and equipment. The properties of the coating depend on its chemical composition and microstructure, which are defined by the dilution with the base metal and the welding process utilized. Therefore, in cladding welding, the control of the present phases in the microstructure is essential to ensure the required properties. The objective of this work was to study the effect of heat input and the amount of layers of superduplex stainless steel deposits on the chemical composition, microstructure, hardness and pitting corrosion resistance. Six cladding coupons were welded by semiautomatic arc welding process: 1 and 2 layers coupons were welded with low, medium and high heat input (modifying only the welding speed). Macro and microstructure was analyzed by optical and scanning electron microscopy and X-ray diffraction. The geometrical and chemical dilutions were determined. Also, Vickers microhardness and pitting corrosion resistance were measured.