Microstructure, Mechanical and Corrosion Behaviour of Dissimilar Weldments between AISI 304 Stainless Steels and AISI 1020 Carbon Steels Produced by Gas Tungsten Arc Welding Using Different Consumables

Gas tungsten arc welding was applied to join AISI 304 stainless steel and AISI 1020 carbon steel sheets with three types of consumables – AISI 308L, AISI 309L and AISI 316L stainless steel wires. Weld metals produced by all consumables exhibited the identical hardness of ca. 350 HV. This value was higher than those of stainless steel and carbon steel base metals, indicating the relatively high strength of weld metals. The corrosive behaviour of weld metals was investigated by a potentiodynamic method. Specimens were tested in 3.5 wt% NaCl solution saturated by laboratory air at 27°C. A pitting potential of weld metal produced by the AISI 309L consumable was higher than those of weld metals produced by the AISI 308L and AISI 316L consumables respectively. The chemical compositions and microstructure of weld metals were also investigated. The pitting corrosion resistance of weld metals produced by different consumables is discussed in the paper in terms of the pitting resistance equivalent number (PREN) calculated from the chemical compositions and the content of delta ferrite in the austenite matrix of the weld metals.