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Plasma transferred arc welding (PTAW) is one of the outstanding overlay coating technique used in numerous industries including pressure vessel, automotive, chemical, nuclear, etc. owing to its superior characteristics, low dilution and high efficiency in the coating. In the present investigations, an effort is made to investigate the multitrack overlay deposition by PTAW on 16 mm thick 316 L plate by CO-Cr alloy. Samples are produced under different processing conditions, as per full factorial central composite design of experiment with preheating of 200°C by maintaining the interpass temperature 250 °C. Effects of transferred arc current, welding travel speed, powder feed rate, welding oscillation speed and stand-off distance on weld bead shape parameters comprising of width of deposition and reinforcement are presented and discussed based on experimental observations and fitted model. Relationship between the input process parameters with deposition characteristics is also presented in the form of regression equation. Lower current (100–120 A), intermediate travel speed (120–140 mm/min), intermediate powder feed rate (12–14 gms/min), lower oscillating speed (450–550 mm/min) and lower stand-off distance (6–8 mm) would give better deposition characteristics with minimum distortion, less residual stresses, no surface defects with strong metallurgical bond.

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Duplex stainless steel 2205 has proven to be the most acceptable material for marine and saline applications because of its superior corrosion resistance with good erosion and wear resistance. However, the disadvantage of stainless steel is its sensitivity to local corrosion in a solution containing chloride, which limits their use in seawater systems. The effect of heat treatment on corrosion properties of stainless steels can be studied in marine or chloride environments and investigation of changes in microstructure and corrosive property. This study presents the consequence of heat treatment on the microstructure and corrosion resistance and systematic approach to examine the corrosion behaviour of plain DSS 2205. Precipitation of secondary parts in DSS 2205 led to an extreme reduction in its corrosion resistance and another factor contributing to changes in ferrite and austenite ratios where preferential corrosion occurred in the DSS 2205 ferrite phase. The austenite phase shows better corrosion resistance than the ferrite phase due to maximum Ni content than ferrite. Cr is the most active element in the passive film to develop the resistance of DSS 2205 to localized corrosion. The heat treatment about 1080°C to DSS 2205 improves the corrosion resistance of steel comparatively.

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