Ravi Shanker Vidyarthy

Ferritic/martensitic steels and austenitic stainless steels are high‐strength steels, and highly recommended in high‐temperature and high‐pressure application. In general, multimetallics with different Inconel alloys are used for joining. This is quite a complex and time‐consuming procedure. The current work demonstrates the efforts made to weld 8 mm‐thick P91 steel and 316L SS plates in a single pass using activating flux tungsten inert gas (A‐TIG) welding process without any interlayers. The main challenge is to get the symmetric weld bead profile. Flux coating is optimized in terms of flux composition, coating density, and coating pattern to get the full penetration with symmetric appearance. The current work discusses the possible cause and their solution of asymmetricity during dissimilar welding. Differential flux coating density is found to be very effective in controlling the arc column shape, fluid flow, and consequently the bead geometry. High coating density is used in the P91 side compared to 316L side. Symmetric weld profile with full penetration is achieved by applying multicomponent flux (33–38% TiO₂, 38–43% SiO₂, 13–17% NiO, and 8–10% CuO) during A‐TIG welding.

BSK 46 is a low alloy structural steel with excellent mechanical and corrosion properties and is widely used in many applications, including tipper bodies of heavy-duty trucks. Optimizing the welding parameters to reduce defects and improve productivity is critical for the users. The present work addresses optimizing the welding process parameters to improve productivity with adequate weld quality during the pulsed gas metal arc welding (P-GMAW) process. Three BSK 46 weldments (weld-1, weld-2 and weld-3) were fabricated by varying the root gap, root face, filler pass and heat input. The metallographic and mechanical characterization of P-GMAW weldments were done through microstructures, Vickers micro-hardness, transverse tensile strength, Charpy toughness and three-point bend test. Subsequently, a correlation has been developed between the microstructural features and mechanical properties of the weld joints. The hardness was found to be incremental in nature from the base metal to the fusion zone. Maximum hardness of 215.81 ± 10 HV was observed in the weld-3 fusion zone. Tensile test results reveal that weld-3 weldments exhibit a higher tensile strength of 547.48 ± 2 MPa than weld-1 (537.46 ± 7 MPa) and weld-2 (533.67 ± 9 MPa) weldments. Maximum impact toughness of 136.33 ± 14 J was observed in the weld-3 weldments. Post-bend testing showed no cracks on the weld surfaces, indicating defect-free weld joints with good ductility. It is observed that weld-3 showed relatively better mechanical properties than weld-1 and weld-2 in lesser welding time and lower welding cost

IRSM 41 is a corrosion-resistant steel widely employed in railway wagons. In the present study, IRSM 41 steel plates of 8 mm thickness were joined using conventional TIG welding (C-TIG) and activated tungsten inert gas welding (A-TIG). Three multicomponent fluxes were utilised during the A-TIG welding. The application of fluxes enhanced the depth of penetration and reduced the bead width. Weldments produced with flux 3 have a thorough penetration of 8 mm in a single weld pass. Bead geometry has been analysed through various aspects such as bead width, depth of penetration and depth-to-width ratio. Metallographic examination and Hardness study of C-TIG and A-TIG weldments was performed. The average fusion zone hardness was found to be better in A-TIG weldments than in C-TIG weldments. The obtained weldments bead geometry and properties have been discussed in contrast of various input parameters.

Hardfacing is one of the preferred ways to prolong the life of machine components. In the current paper, efforts have been made to evaluate the flux composition on the hardness and wear behavior of a hard-faced surface. The shielded metal arc welding process was used to deposit the hardfacing layer over low carbon steel. Six different types of iron-based multicomponent flux compositions were developed using FeCr (25–30%), FeV (5%), FeMo (3–4 %), FeTi (2–3 %), Nb (3–4 %), and CeO2 (1–5 %) for hardfacing. The properties of the overlayer were examined using the microstructure study, hardness study, and abrasive wear test. Microstructural characterization was done using an optical microscope and field emission scanning electron microscope. X-ray diffraction was performed to examine the nature of precipitate formation. The worn-out surface and the debris were further examined, employing scanning electron microscopy to study the wear mechanism. The hard-faced surfaces revealed the presence of columnar and dendritic grains. Equiaxed grains were also observed in the sample, which was hard-faced with FeV. The hardness of the hard-faced surfaces was determined using the Vicker’s macro-hardness tester. A maximum hardness of 846.5 ± 2.5 HV was observed for weld overlay. The sliding wear behavior of the surface was investigated using an abrasive wear test performed on the pin-on-disk apparatus. The addition of vanadium to Fe-Cr-C hardfacing flux increased hardness and wear resistance between 3.5 and 6 times, respectively.