Open AccessEnhancing corrosion resistance of A-TIG welded UNS S32750 joints by optimizing its technological parameters
Author(s) -
A. Arunmani,
T. Senthilkumar
Publication year - 2020
Publication title -
chemical industry and chemical engineering quarterly
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.189
H-Index - 26
eISSN - 2217-7434
pISSN - 1451-9372
DOI - 10.2298/ciceq190419001a
Subject(s) - welding , materials science , inert gas , gas tungsten arc welding , corrosion , metallurgy , shielding gas , tungsten , pitting corrosion , volumetric flow rate , inert , composite material , heat affected zone , arc welding , chemistry , mechanics , organic chemistry , physics
In this paper, an attempt was made to improve the corrosion resistance of activated tungsten inert gas welded super duplex stainless steel such as UNS S 32750. Joints were fabricated by fluctuating the important process parameters such as welding speed, shielding gas flow rate and welding current, using NiO as activation flux. A central composited design model was developed for identification of the Activated Tungsten Inert Gas welding process parameter values for fabricating twenty joints. The welded joints were subjected to pitting corrosion test using an electrochemical corrosion testing system and salt spray testing was done for 48 h. Empirical relationships were developed for the process parameters with variations in the pitting potential and the rate of mass loss. The significance of the developed model was ascertained using analysis of variance method and optimization was done using response surface methodology. The joints fabricated at welding speed of 54.26 mm/min, welding current of 157 A and gas flow rate of 14.8 L/min, were found to have maximum pitting potential of -252.36 eV and minimum mass loss of 0.0108 g. Using validation experiments, the error was identified within three percentage which indicated that the optimization model was developed with very high predictability.