Anticorrosion Performance of FCAW Cladding with Regard to the Influence of Heat Input

Heat input plays a significant role in flux cored arc welding (FCAW) for producing quality welding. Weld cladding improves corrosion resistance and other mechanical properties. Selection of appropriate heat input is required to get optimum quality of the cladding. In this experiment, FCAW cladding of duplex stainless steel is done on low alloy steel under CO2 gas shield. Three sets of heat input are chosen for experimentation in which each level of heat input comprised of three sets of current and voltage in such a way that the heat input level remained nearly constant. The output parameters like corrosion rate is measured and microstructures are evaluated. The relationship between heat input and corrosion rate is evaluated by means of polynomial regression analysis and the results matched with proposed model with small variations. The results showed that corrosion rate increases with increase in heat input within the experimental domain. Minimum corrosion rate is obtained in the present investigation at 0.49 kJ/mm heat input with 170A weld current, 27V weld voltage and 7.5 mm/s weld torch travel speed. For a particular heat input, corrosion rate is found to vary with different weld current. Microstructure of duplex stainless steel cladding shows presence of austenite phase, and ferrite phase. For an increase in heat input, the microstructure of clad part sacrifices more amount of ferrite phase that exhibits more amount of corrosion. Key words: Cladding, Flux cored arc welding, Heat input, Corrosion resistance, Process parameters, Regression analysis