Higher productivity is registered with Flux cored arc welding (FCAW) process in many applications. Further, it combines the characteristics of shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and submerged arc welding (SAW) processes. This article describes the experimental work carried out to evaluate and compare corrosion and its inhibition in SA 387 Gr.22 (2.25Cr-1Mo) steel weldments prepared by FCAW process with four different heat inputs exposed to hydrochloric acid medium at 0.1, 0.5, and 1.0 M concentrations. The parent metal, weld metal, and heat-affected zone are chosen as regions of exposure for the study carried out at 100°C. Electrochemical polarization techniques such as Tafel line extrapolation (Tafel) and linear polarization resistance (LPR) have been used to measure the corrosion current. The role of hexamine and mixed inhibitor (thiourea + hexamine in 0.5 M HCl), each at 100 ppm concentration is studied in these experiments. Microstructural observation, hardness survey, surface characterization, and morphology using scanning electron microscope (SEM) and x-ray diffraction (XRD) have been made on samples to highlight the nature and extent of film formation. The film is found to contain FCAW is a better alternative to SMAW, and its extensive use is due to inherent process and metallurgical advantages (Ref 1, 2) such as: (i) high-quality weld metal (WM) deposit, (ii) excellent weld bead appearance, (iii) higher deposition rate (four times more than SMAW), (iv) reduced distortion, and (v) higher tolerance for contaminants that may cause weld cracking, and (vi) resistance to under bead cracking. In addition to these, a faster burn off rate for tubular FCAW is promoted by higher current densities at the wire tip. Also the duty cycle obtainable with the FCAW process is higher than GTAW and SMAW. The higher duty cycle can be attributed to two main factors: the continuous nature of the process and all-positional capability of the process without the need for a change in the welding parameters. In all the arc welding processes (Ref 3, 4), intense heat source produced by the arc and the associated local heating and cooling result in a number of consequences in material corrosion behavior, and several metallurgical phase changes occur in different zones of a weldment. Because corrosion phenomenon is due to occurrence of electrochemical potential gradient in the adjacent sites of a WM, it is proposed to study the effects of welding on the corrosion behavior of these steels. The fossil fuel-fired boilers (Ref 5-7) and power generating equipment experience corrosion problems in such components as steam generators, water walls surrounding the furnace, and in the front and rear portions of the superheater and reheater. These components are often made of carbon and Cr-Mo steels. The water used for raising steam in any boiler installation often contains gaseous impurities and dissolved solids. These can cause scaling and corrosion in the boiler plant. Apart from these, some of the inorganic salts hy...
