Welding Metallurgy of

Recently, the pulsed current tungsten arc welding process (PC-TAW) has cemented their potential in various sorts of industrial application such as automobile, aerospace, and structural joining. However, the involvement of multiple process parameters in PC-GTAW process usually makes the process cumbersome to understand; and thereby, it is difficult to develop the mathematical model. Here, in this scientific work, the major efforts have been made to optimize multiple parameters for selected output responses through the use of evolutionary computational approaches. For this purpose, the particle swarm optimization (PSO), simulated annealing (SA) algorithm, and hybrid PSO-SA (HPSOSA) techniques have been employed and compared in terms of the quality responses for input parameters. From the soft computing modeling results, it has been observed that the HPSOSA improved the process performance and has revealed the global optimal solution within minimum interval of time. The developed models were statistically significant at 95% confidence interval. The experimental and mathematical outcomes for the welded specimens are duly supported with microscopic analyses.

Multi-objective parametric appraisal of pulsed current gas tungsten arc welding process by using hybrid optimization algorithms

Development of welding technique to avoid the sensitization in the alloy 600 by conventional Gas Tungsten Arc Welding method

Water cooling assisted laser dissimilar welding with filler wire of nickel-based alloy/austenitic stainless steel

Wire arc additive manufacturing (WAAM) technique became an emerging manufacturing technology because of its cost-effective in creating large-scale metal parts with moderately high deposition rates. Mainly, WAAM works through the utilization of heat source as an electric arc by melting the metal wire to build the three-dimensional metal parts in a layer-by-layer approach, which may significantly minimize the fabrication costs compared to powder and other additive manufacturing techniques such as laser and electron beam, similarly. This article reviews WAAM processes and methods and gives an exhaustive overview of the residual stresses, microstructures, and material properties of the as-fabricated and post-fabrication treated WAAM components. The typical defects during the fabrication of metal components by the WAAM process are residual stresses, deformity, porosity, and cracking. And also, methods on controlling residual stresses, improving material properties, and effects of post-processing treatments to enhance the part quality fabricated by using the WAAM process are recommended in this review. Finally, the measurement methods of residual stresses in the metal parts and FEA simulations in the WAAM are discussed. FEA simulations provide better insights on moving heat source model, temperature distributions, and residual stresses in the WAAM process. This article concludes that selecting process parameters affects the quality WAAM component during the deposition process. And also, approaches to improving the part quality are proposed. The materials fabrication issues in the WAAM processes were outlined, and the advanced WAMM processes were suggested to obtain high quality and defect-free WAAM parts.

Assessment of Process, Parameters, Residual Stress Mitigation, Post Treatments and Finite Element Analysis Simulations of Wire Arc Additive Manufacturing Technique

The present work investigates the microstructure and mechanical properties of alloy C-276 fabricated by continuous and pulsed current gas tungsten arc welding process and by employing ER2553 filler wire. Optical and scanning electron microscopic analyses were carried out to study the microstructures of weldments produced. Energy dispersive X-ray spectroscopy (EDS) was performed to investigate the formation of secondary phases in the weldments. The results disclosed that pulsed current gas tungsten arc welding showed refined microstructure compared to continuous current gas tungsten arc welding. SEM/EDS analysis revealed the segregation of Mo in the weld interface regions in both the welding techniques. The extent of microsegregation reduced the strength and toughness of the weld joint compared to the base metal. Bend test revealed cracks in the weld interface region in both the weldments.

Analysis of Metallurgical and Mechanical Properties of Continuous and Pulsed Current Gas Tungsten Arc Welded Alloy C-276 with Duplex Stainless Steel

The needs of the dissimilar weld joint between superalloy and stainless steel is increasing in many industries. Gas tungsten arc welding (GTAW) and shield metal arc welding (SMAW) are the most common methods used to fabricate the weld joints in the fabrication industry due to its high versatility in the fabrication of industrial components and parts. The present study investigated the metallurgical and mechanical properties of bimetallic joints fabricated between nickel-based superalloy Incoloy 800 and stainless steel AISI 316L. The weld joints were fabricated by using ERNiCrMo-3 filler wire. The micrograph of weld fusion zone revealed the austenitic microstructure with columnar dendrite and cellular structure in both weldments. SEM/EDS analysis witnessed the precipitation of Nb-rich phase in the weld fusion zone fabricated by SMAW process, and it was minimized in case of GTA welding technique. The strength and toughness of the weld joint fabricated by GTAW improved 14 and 25% respectively when compared to SMAW technique.

Comparative Studies on Metallurgical and Mechanical Properties of Bimetallic Combination on Incoloy 800 and SS 316L Fabricated by Gas Metal and Shield Metal Arc Welding

Alloy C-276 susceptible to hot cracking. The microsegregation occurs during solidification is the largely responsible for the hot cracking in the alloy. The present study investigates the microstructure and mechanical properties of alloy C-276 weld joint fabricated by ATIG welding technique. The macro examination was carried out assess the defects in the weld joints. Optical and scanning electron microscope examination was carried out to see the structural changes in the fusion zone. The tensile test was performed to evaluate the strength of the weld joints. The results show the defect free welding was achieved in the established process parameters. The macrograph shows the full depth of penetration was obtained in the single pass by the effect of Marangoni convection. Energy Dispersive X-ray spectroscopy (EDS) analysis illustrates the absence of microsegregation in the interdendritic zone. The tensile test shows the improved mechanical properties compared to the base metal.

Investigation on Microstructure and Mechanical Properties of ATIG welded alloy C-276 with Fe2O3 flux

https://robots.iopscience.iop.org/article/10.1088/1757-899X/402/1/012075/pdf

Deva N. Rajan

Papers

Analysis of Metallurgical and Mechanical Properties of Continuous and Pulsed Current Gas Tungsten Arc Welded Alloy C-276 with Duplex Stainless Steel

Comparative Studies on Metallurgical and Mechanical Properties of Bimetallic Combination on Incoloy 800 and SS 316L Fabricated by Gas Metal and Shield Metal Arc Welding

Investigation on Microstructure and Mechanical Properties of ATIG welded alloy C-276 with Fe2O3 flux

Investigation on microstructure and tensile properties of dissimilar weld joints between AISI 316l and duplex 2205 stainless steel