Firefly Algorithm and Neural Network Employment for Dilution Analysis of Super Duplex Stainless Steel Clads over AISI 1020 Steel Using Gas Tungsten Arc Process

Traditional low-carbon steels provide the strength needed to satisfy industrial demands. Low-carbon steel’s poor corrosion resistance is one of its main drawbacks. Due to this restriction, corrosion-resistant materials such as super duplex stainless steels are frequently used for cladding onto the surface of low-carbon steel. The cladded surface possesses superior chloride stress corrosion cracking resistance, pitting and crevice corrosion resistance, yield strength, ductility, and impact toughness. Mild steel with measurements of 300 × 300 × 12 mm has been selected as the substrate material, and super duplex stainless steel (S32950) with an electrode diameter of 2.4 mm has been selected as the filler wire. Gas Tungsten Arc (GTA) cladding was performed onto the surface of low-carbon steel for experimentation. The clad was deposited in the flat position with four different currents, i.e., 120 A, 130 A, 140 A, and 150 A. Cladding was performed on different layers of each current level, i.e., single layer, double layers, and triple layers. After experimenting and overviewing the outcomes, it can be concluded that the optimum input parameters would be a 3-layered clad at a 140 A current level. Cladding of the super duplex stainless steel over mild steel improves the corrosive properties. The percentage ratio of reactivation current density to activation current density (Ir/Ia%) improves from 29% (mild steel) to 4.1% at the top layer and 11.9% at the intermediate layer. The microhardness of the clad decreases with an increase in both the current level and the number of layers. Microhardness varies between 191–248 at the clad, 170–189 at the HAZ, and 143–153 at the substrate for a 1 kgf load. Dilution refers to the change in the cladding alloy composition due to the mixing of the molten matrix. The composition of the clad changes under a high dilution, resulting in a decrease in the mechanical as well as corrosion properties of the clad. However, if the dilution is too small, the bond between the substrate and the clad is poor. Therefore, dilution is one of the most important process control parameters and the key to obtaining high-quality cladding. Thus, the dilution effect is also analyzed on all three clad layers deposited at various current levels using the firefly algorithm (FA) and artificial neural network (ANN). It is observed that dilution levels are found to be more approachable to the experimental setup data with FA in comparison to ANN for various current levels.