Comparative Analysis of Mechanical Properties of Inconel and Martensitic Stainless Steel Joints Achieved by Tungsten Inert Gas Welding

In present research work, discussions have been made to predict the bead geometries and shape profiles of weldments using statistical regression modeling and fuzzy logic techniques. However, the regression and fuzzy logic modeling techniques do not take into account the actual physical properties and phenomena that occur in welding. Moreover, techniques such as regression and fuzzy logic modeling are not suitable for predicting the transient temperature distribution and distortion of arc welded joints. To predict the transient temperature distributions, peak temperature distribution, and residual deformation in welding, deterministic modeling techniques such as thermomechanical analysis are preferred. However, while performing thermomechanical analysis of welded joints, size and reinforcement dimensions of the weld bead need to be incorporated into the model for accurate prediction of transient temperature distributions and distortions. In this work, circularly spread moving heat source has been used for transient thermal modeling of tungsten inert gas (TIG) welding process. In the subsequent sections of this article, the weld thermomechanical analyses for TIG square butt joints are discussed to predict the temperature distributions and angular distortion. The weld dimensions such as weld width, weld depression, and weld bulging have shown great influence on the angular distortion patterns. 1. Introduction The present work describes the thermomechanical analysis of an open arc process, i.e., tungsten inert gas (TIG) welding of square butt joints by considering the circularly spread moving heat source to predict the angular distortion and thermal profile (Pandey et al. 2016). TIG welding is commonly used for thin sheet joining (Pandey et al. 2018a, 2018b). Generally, for thin sheets, the TIG welding is performed autogenously such that no filler material is required. In some special cases, such as for fillet and groove welding, a filler rod is used in the TIG welding process. The distortion of the TIG weld square butt joints is primarily dependent on the weld width, bead depression, and bulging (Mahapatra et al. 2006). If these factors of weld bead geometries are within tolerable limits, then, the distortion observed in the weld joint is minimum. In TIG weld butt joints, the angular distortion is more prominent because of the presence of upper bead depression and lower bead bulging. Finite element analysis (FEA) simulation of TIG welding is highly effective in predicting the thermomechanical behavior such as temperature distributions and distortions. In this work, numerical and experimental approaches have been applied to predict the thermal profile and angular distortion in a TIG open arc welding process. An Finite element (FE) model has been developed for 3-D analysis of TIG square butt joints for predicting angular distortion based on circularly spread moving heat source and weld geometry.

Tungsten inert gas (TIG) welding has an inherent difficulty in achieving deep penetration. To improve the penetration in TIG welding process, many researchers are continuously working in this field. In this paper, weld penetration of bead on plate TIG welding was compared with flux-bounded TIG (FBTIG) welding which was carried out on 6-mm-thick P91 plates. In the present FBTIG welding, a ceramic flux consisting of alumina was used instead of silica. Sodium silicate was used instead of acetone in the experiments to bind the flux on to the plates. In this paper, bead on plate FBTIG welding was carried out to investigate whether weld penetration could be improved. It was observed that with FBTIG welding, using ceramic flux, the weld penetration increased 2–3 times the penetration obtained during TIG welding. The weld width in all the cases decreased compared with conventional TIG welding. The effect of flux gap on hardness and grain size at the heat-affected zone were also investigated. Compared with TIG welds, FBTIG-welded samples had larger grain size and lower hardness values in the welded and heat-affected zone.

Investigation of heat transfer and fluid flow in activating TIG welding by numerical modeling

Austenitic stainless steel (ASS) plays an important role in fabrication and manufacturing of products due to its good mechanical properties and easy weldability mostly for all types of welding. In fabrication, there are numerous welding techniques available for ASS such as gas metal arc welding, tungsten inert gas (TIG) welding, electroslag welding, submerge arc welding, electron beam, thermite welding. TIG welding is the most common operation use for joining of two similar or dissimilar metals with heating or applying the pressure by using the filler material. TIG welding technique is used in several industries like automobile, aerospace, marine, etc. due to its quick and precise process. This paper systematically reviewed the TIG and A-TIG welding processes of ASS which included several recent experimental activities. In TIG welding, the inputs such as voltage, current, filler materials and shielding gasses, the type of flux and passes ultimately affect its output weld quality. In addition, a comparison has been provided for parameters of TIG and A-TIG welding process and their weld outcomes such as microstructure, mechanical, penetration depth, and weld bead quality. A-TIG has better hardness and mechanical properties than TIG welding.

The aim of this study was to compare the mechanical strength and microhardness of joints made by conventional brazing and tungsten inert gas (TIG) and laser welding. A standardized end-to-end joint configuration of the orthodontic wire material in spring hard quality was used. The joints were made using five different methods: brazing (soldering > 450 degrees C) with universal silver solder, two TIG, and two laser welders. Laser parameters and welding conditions were used according to the manufacturers' guidance. The tensile strengths were measured with a universal testing machine (Zwick 005). The microhardness measurements were carried out with a hardness tester (Zwick 3202). Data were analysed using one-way analysis of variance and Bonferroni's post hoc correction (P < 0.05). In all cases, brazing joints ruptured at low levels of tensile strength (198 +/- 146 MPa). Significant differences (P < 0.001) between brazing and TIG or laser welding were found. The highest means were observed for TIG welding (699-754 MPa). Laser welding showed a significantly lower mean tensile strength (369-520 MPa) compared with TIG welding. Significant differences (P < 0.001) were found between the original orthodontic wire and the mean microhardness at the centre of the welded area. The mean microhardness differed significantly between brazing (1.99 GPa), TIG (2.22-2.39 GPa) and laser welding (2.21-2.68 GPa). For orthodontic purposes, laser and TIG welding are solder-free alternatives to joining metal. TIG welding with a lower investment cost is comparable with laser welding. However, while expensive, the laser technique is a sophisticated and simple method.

How the quenching and partitioning (Q&P) steel with an ultrahigh strength (>1 GPa) behaves during the welding process is a considerable issue for its practical application, but the systematical evaluation on the welding behavior of this new steel has not yet been concerned. Here the structure-property relationships of three typical Q&P 1180 steel joints were comparatively studied by using laser welding (LW), tungsten inert gas (TIG) welding, and friction stir welding (FSW). Weld metal (WM) region and heat-affected zone were generated in the welded joints and their widths were mainly related to the welding linear energy (LW < FSW < TIG welding). During LW and TIG welding, the parent metal (PM) was totally destroyed and coarsened in the WMs whereas ultrafine microstructures with high hardness were obtained after FSW by means of the low peak temperature and severe plastic deformation. The TIG welding produced serious material softening, while the softening degree could be alleviated via LW and FSW. Excellent tensile strength as high as that of the PM was achieved in both the LW and FSW joints by means of the suppressed material softening as well as small soft zone width. However, dramatic losses of strength and ductility were found in the TIG welded joint owing to the premature strain localization and fracture in the soft zone.

Austenitic Type 316L stainless steel plates of very large thicknesses are considered for use in vacuum vessel fabrication in advanced fusion reactors. The possible options for welding of higher-thickness plates are multipass tungsten inert gas (TIG) welding, narrow gap–TIG welding, and electron beam welding (EBW). The manufacture of double-wall vacuum vessel inner components like keys, shells, and ribs are planned to be fabricated using EBW, and some components like field joints are to be fabricated using TIG welding processes. The present paper reports the fabrication of 60-mm-thick Type 316L stainless steel welded samples with multipass TIG welding and EBW processes and sample property characterization studies. The fabricated weld samples have been tested for weld defects with nondestructive tests using X-ray radiography and ultrasonic scan tests. The welded samples have been characterized for mechanical properties such as tensile, bend, Vickers hardness, and Charpy V-notch impact tests. Microstructure analysis has been carried out for both welded samples for the base metal, heat-affected zone, and weld zone. Impact-tested sample fracture analysis has been done by scanning electron microscopy.

An Analysis of the Mechanical Behavior of AISI 4130 Steel after TIG and Laser Welding Process

Tungsten inert gas (TIG) welding is one of the most popular welding which has high quality welds. TIG welding can be used for all kinds of welding positions and high efficient. During the welding process, the welding specimen and the heat affected zone (HAZ) affected by a series of thermal cycles where the area warms up to a maximum temperature then followed by cooling process. The thermal cycle affects the microstructure of the welding specimen and HAZ. By controlling these parameters to reach the right heat cycle, the mechanical property of the weld metal can be improved and maintain the microstructure of the weld metal. This study is conducted an experiment to determine the effect of different wind velocity around the TIG welding material. Moreover, this study also discuss the effect of shielding gas flow rate on TIG type welding on JIS G 3131 SPHC steel material. The welding area and HAZ the higher the wind speed the hardness value tends to decrease. Because there is a difference in cooling speed and heat input on weld metal and HAZ.

Effect of thermal stability of powdered oxide on joint penetration and metallurgical feature of AISI 4130 steel TIG weldment

Effect of fluxes on weld penetration during TIG welding – A review

This study tackles the challenges of inconsistent weld quality and limited real-time monitoring in Tungsten Inert Gas (TIG) welding by developing a digital twin for the process. The primary objective is to enhance process efficiency and quality control by creating a high-fidelity virtual model of TIG welding that enables real-time monitoring and control. To achieve this, the study employs Desirability Function Analysis (DFA) to optimize multiple quality characteristics. The methodology integrates advanced sensors and IoT technologies to gather real-time data on critical welding parameters such as current, voltage, travel speed, and gas flow rate. This data is used to create a simulation model that accurately replicates the physical welding process. The experiments are conducted using digital twin on SS304 thin which is widely used in industrial applications. By applying DFA, the study converts multiple quality characteristics into a single composite desirability score, offering a quantitative assessment of process efficiency and output quality. The experimental results demonstrate the digital twin’s ability to accurately predict and control welding outcomes, significantly improving productivity and quality control. This research highlights the transformative potential of digital twin technology in TIG welding, paving the way for smarter, data-driven decision-making in industrial settings.

Effect of flux addition on the microstructure and tensile strength of dissimilar weldments involving Inconel 718 and AISI 416

Comparative study of AISI 304L to AISI 316L stainless steels joints by TIG and Nd:YAG laser welding

Development of a novel autogenous double pulse tungsten inert gas welding technique for joining IN625 in concentrated solar power plants