Tungsten Inert Gas Welding Welding Research Articles

A study on the mechanical, electrochemical and microstructural behaviour of AA5052 welded sheets

Aluminium 5xxx series alloys are most robust non-heat-treatable aluminium alloy and mostly used in aerospace, automotive components and body structures due to its high corrosion resistance, good strength and light weight. The alloy used in this work is AA5052 H32 (cold rolled) of 1 mm thickness to highlight the precedence of friction stir welding (FSW) over fusion welding technique, i.e., Tungsten Inert Gas welding (TIG). In TIG, the selected input variable parameter is welding speed and the other parameters such as inert gas flow rate, welding speed and frequency were kept constant during the study. In FSW, the selected input variable is feed rate, and the parameters such as plunge depth and tool rotational speed were kept constant after conducting several trials. Mechanical, Electrochemical, and Microstructural behaviour of both welded samples were studied. It was found that Friction stir welding samples has better mechanical properties than TIG welding due to solidification cracks and porosity defects. The tensile and microhardness results of FSW were 7.3 % and 5.4% more than TIG due to solidification cracks, porosity defects and intermetallics formed. The corrosion behaviour of both FSW and TIG were less than the base material due to precipitate dissolution. In the present study a comparative study of FSW and TIG is studied and reported.

Microscopic and Mechanical Characterization of Co-Cr Dental Alloys Joined by the TIG Welding Process.

Due to their good mechanical and other properties, cobalt-chromium alloys (Co-Cr) are often used in prosthetic therapy. The metal structures of prosthetic works can be damaged and break, and depending on the extent of the damage, they can be re-joined. Tungsten inert gas welding (TIG) produces a high-quality weld with a composition very close to that of the base material. Therefore, in this work, six commercially available Co-Cr dental alloys were joined by TIG welding, and their mechanical properties were evaluated to determine the quality of the TIG process as a technology for joining metallic dental materials and the suitability of the Co-Cr alloys used for TIG welding. Microscopic observations were made for this purpose. Microhardness was measured using the Vickers method. The flexural strength was determined on a mechanical testing machine. The dynamic tests were carried out on a universal testing machine. The mechanical properties were determined for welded and non-welded specimens, and the results were statistically evaluated. The results show the correlation between the investigated mechanical properties and the process TIG. Indeed, characteristics of the welds have an effect on the measured properties. Considering all the results obtained, the TIG-welded I-BOND NF and Wisil M alloys showed the cleanest and most uniform weld and, accordingly, satisfactory mechanical properties, highlighting that they withstood the maximum number of cycles under dynamic load.

Improvement in the microstructural properties of super duplex and austenitic stainless steel dissimilar joints by incorporating Ni-based austenitic interlayer

Tungsten inert gas welding (TIG) has remained a worldwide utilized welding technology in the industry to till date. Activated tungsten inert gas welding (ATIG) is also an advanced variant of TIG to enhance the penetration depth and reduce the width of the weld bead in single-pass compared to traditional TIG welding. The current study focuses on utilizing the Inconel interlayer approach to link dissimilar cold-rolled super duplex and austenitic stainless steels, which are mostly used in the offshore and marine industries. A systematic strategy is used to emphasize the studies conducted after using the ATIG interlayer procedure over the traditional TIG interlayer welding process. The research also studies and compares the microstructure, elemental mapping of the weld interface, phase identification and mechanical properties of dissimilar welded super duplex and austenitic steel samples. • ATIG welding approach for achieving single pass penetration of 6 mm thick plate with reduced weld heat input. • Without any weld defects such as weld porosity, undercut, overlap defect, and hot cracking a dissimilar welding of austenitic 202 and super duplex 32760 plates were successfully completed. • Microstructure evolution such as reduction in the width of heat affected zone, and reduction in the width of the unmixed zone was seen after using the ATIG interlayer weld technique. • Mechanisms such as reverse Marangoni and arc constriction in ATIG welding techniques could easily reduce parent metal loss in weld zones.

A New Perception of Activated Flux Tungsten Inert Gas (A-TIG) Welding Techniques for Various Materials

Tungsten inert gas welding (TIG) is more stable and allows for more precise control than most other arc welding processes. TIG welding is desired in the aerospace sector when thin parts have been welded with accuracy. However, when welding thick sections, autogenous TIG welding is not commonly recommended due to the limited depth of penetration required. It is in effective for joining the thick parts in a particular pass. Welding with activated flux tungsten inert gas (A-TIG) enhances weld penetration by four times in a single pass. This process will improve penetration depth, depth/width ratio and also, minimize angular distortion and residual stresses. A-TIG is the topic of investigation among researchers due to its deep penetration capacity. Properties of A-TIG welding in diverse materials was investigated in this study which also discusses the mechanisms, varied forces like lorentz force, buoyancy force, shear stress prompted by plasma jet, shear stress prompted by surface tension gradient, reverse marangoni force and aerodynamic drag force induced in the weld pool. The impact of activated fluxes on various materials of A-TIG weld was also investigated in this study. Recent advancements in TIG welding methods were also explored. According to the findings, A-TIG welding improves weld penetration significantly, but there is a lot of slug on the weld surface. This constraint can be addressed by using new versions of the A-TIG welding progression, such as flux bounded and the flux zone.

Welding simulation of circumferential weld joint using TIG welding process

Circumferential weld joints are commonly used in marine engineering, nuclear power plant, aerospace industry. In this welding simulation of circumferential weld joint using Tungsten inert gas welding (TIG) process was done. In TIG welding joint the high temperature is induced due to which there is high distortion and residual stress. For that developing a good welding joint in controlled residual stress and deformation we are using the Welding simulation Finite element methodology. A SS304 material with TIG welding is selected as experimental and combination of Finite Element Analysis (FEM) using the MSC marc software to predict the temperature, residual stresses and distortion with varying cylindrical thickness, voltage, pressure and efficiency. Using finite element simulations, the welding heat input is varied by modifying welding parameters (such as welding current and welding speed) to study the effect on residual stresses. The aim of this research is to provide information to verify the validity of current process circumferential manufacturing technology for thin-walled pipes, in order to prevent the failure of these structures in operation due to these inherent stresses. The study's welding heat source model is the Double Ellipsoidal Heat Source Model, which is the best heat source model of welding simulation.

Investigating the Effect of TIG and FSW Joint Design on the Mechanical Properties of the AA5083 Aluminum Alloy in Welding Processes

The 5083 aluminium alloy is one of the alloys of the 5xxx series that is widely used in defence and shipbuilding industries. In this study, the 5083 aluminium alloy plates were evaluated through two friction stir welding and tungsten inert gas welding (TIG) by a double groove weld with a 30° angle and a 2mm gap for TIG and a simple butt weld for FSW. In this study and in addition to examining the samples' mechanical properties, the microstructure changes and the hardness were also reviewed. The results show that the FSW weld has better mechanical properties than the TIG weld due to fast welding speed. However, by preparing the pieces, the mechanical properties of TIG get closer to those of FSW. In the FSW welding in the weld nugget, the grains have a fine and co-axial structure, and an increase in the advance rate will reduce the inlet heat and make the grains smaller. Nevertheless, in TIG welding at high speeds, the grains become more extensive with increased inlet heat.

Effect of Friction Stir Processing on Microstructure and Mechanical Properties of TIG Welded Joint of AA6061 and AA7075

In tungsten inert gas welding (TIG), micro-cracks, porosity, coarse grain structure and high residual stress distribution were found due to persisting thermal conditions. The TIG welded joint is processed using friction stir processing with input process parameters to avoid these defects. In present work, the experimental investigation was conducted to examine the influence of friction stir processing (FSP) on microstructure and mechanical properties of TIG welded joint of AA6061 and AA7075. Tensile test, Vickers hardness test, x-ray diffraction, microscopy and energy-dispersive x-ray test were performed for concluding the optimum set of parameters. The tensile test results shows that the hybrid TIG + FSP welded joint had higher tensile strength than TIG welded joint with filler ER4043, whereas the increment in the micro-hardness of TIG + FSP welded joint was observed. The grain size also decreases when tool pin rotates on TIG welding with different processing parameters. It was found that the maximum tensile stress, % elongation and micro-hardness at nugget zone for TIG + FSP welded joint are 255 MPa, 29.2, and 105 HV respectively. The present investigation demonstrates that the tool rotational speed and traverse speed are the dominating parameters to improve the mechanical properties of TIG welded joint.

“Effects of using oxide fluxes as activating flux on Activated flux Tungsten Inert Gas welding” – A review

Tungsten Inert Gas welding (TIG) is preferred in the Aerospace Industry where thin sections have to be welded with quality and precision. But, when thick sections are to be welded, conventional TIG welding is not usually preferred due to low penetration depth necessitating more passes. Activated flux Tungsten Inert Gas (A-TIG) welding was invented to improve productivity when welding thick sections. This study reviews the effects of using oxide fluxes in the A-TIG welding.

Analysis and Characterization of the Weld Pool and Bead Geometry of Inconel 625 Super-TIG Welds

The welding market is changing globally, becoming eco-friendly, robotized and automated. The tungsten inert gas welding (TIG) process is indispensable in industries that require high-quality welds with the absence of spatter and fumes. However, the production rate of TIG welding is very low, which limits its many applications. The present study introduces a novel TIG welding method called super-TIG welding. Super-TIG welding is able to produce a high production rate of welds compared to other fusion welding methods. In super-TIG welding, the novel C-type filler is used, which is different from the conventional TIG welding of circular wire. The relations of the heat input ratio in super-TIG welding to weld pool length and weld bead geometry were measured using the Inconel 625 C-filler. Two types of deposition techniques were used for a bead-on-plate welds, such as stringer beads and oscillation beads. The weld pool and bead geometry measurements are found to be different between stringer beads and oscillation bead techniques. The length of the molten pool and bead size were higher for oscillation beads over the stringer beads. These changes were associated with the difference in heat transfer contact area and bead height.

Factorial approach to estimate angular distortion in TIG welding of high strength low alloy steels

Tungsten inert gas welding (TIG) is primarily an autogenous joining process which is extensively used for welding thin sheets. The process is highly versatile and can weld any metal with excellent weld quality. Like other arc welding processes, rapid heating and cooling cycles are encountered in this process as well, which result in uneven thermal expansions and contractions in the weld ment giving rise to stresses. These thermally generated stresses result in the weld distortions. Weld distortions are non desirable as they not only spoil the physical appearance but also change the shape of the weld, creating assembly related problems later on. Though various types of weld distortions are there, the literature survey however reveals that the most prominent is the angular distortion. The present investigation work has been carried out to analyse the effects of various welding input parameters like welding current, welding speed and torch angle on angular distortion during TIG welding of high strength low alloy steels (HSLA). Theses steels are finding increased applications owing to their low costs, less alloy contents and high mechanical properties. A mathematical equation has been developed by using statistical technique of full factorial design. The direct and interactive effects of the input parameters were analyzed and presented in graphical forms.

Microstructure and mechanical properties of stainless steel clad plate joints produced by TIG and MAG hybrid welding

This paper investigated the microstructure and mechanical properties of Q235/304 stainless steel clad plate welding seam produced by hybrid welding of tungsten inert gas welding (TIG) and metal active gas arc welding (MAG). The results showed that the dual phases containing ferrite and austenite appeared in the stainless steel covering welding (SSCW), while the partial martensite phases appeared in the carbon steel backing welding (CSBW), which is attributed to the dilution behavior of Ni and Cr elements from stainless steel to the Q235 steel results into the movement of the CCT curve to the right side and the decrease of critical martensite formation cooling rate. The CSBW possesses the highest microhardness value in the weld metal due to the existence of the martensite zone. The impact tests were carried out and the results showed that the Charpy absorbed energy of weldments (81 J) is almost equal to that of base clad plate (83 J). The SSCW layer possesses the ductile fracture characteristics accompanying many dimples. However, in the CSBW layer, some cleavage fracture characteristics are presented in the radiation zone while many dimples are located in the fibrous zone, revealing a complex combination of brittle and ductile fracture behavior, which is due to the existence of martensite zone, different stress states and crack propagation velocity.HighlightsHybrid (TIG, MAG) welding is suitable for welding stainless steel clad plate;The martensite formation in CSBW is related to dilution and diffusion of Cr and Ni;Partial martensite transformation can strengthen and toughen the welding seam.

Analysis of Fiber Optic Sensor Embedded in Metals by Automatic and Manual TIG Welding

In this paper, the embedding of fiber optic sensors in metals, by using both automatic and manual tungsten inert gas welding (TIG) is discussed for nickel- and copper-coated fiber Bragg gratings (FBG) written into an optical fiber, as embedding such sensors in metals provides protection against environmental effects. In the investigation and analysis of the performance of a number of such sensors, copper-coated sensors were seen to lose their temperature and strain sensitivity while being embedded due to damage to the coating, while with a nickel coating the sensors in the fiber were found to withstand the process with a lesser effect on the sensor performance. The research has also shown that the automatic TIG process used is less invasive than the manual TIG approach, although more expensive to implement.

Experiment on GTAW of AL 6061-T6 Material With SUS 304

GTAW well known as tungsten inert gas welding (TIG) commonly used to join thin sections of non-ferrous metals like magnesium, copper and aluminium alloys. Allowing for stronger, higher quality welds the welding operator need great control on welding process. Because of short arc length, contact gap of filler electrode have to be maintain in a even way to maintain equal speed and depositing methods. Present work focuses on the TIG welding process and microstructure analysis of flaws in welding; also evaluate the mechanical properties of welded joints. The samples prepared as per ASTM weld samples, the extracted samples tested for microstructure, penetration and other mechanical tests. The results are showing good at the area of weld.

Evaluation of mechanical properties for TIG welding aspects of SS 310 and MS materials

Abstract Tungsten inert gas welding (TIG) is being extensively used as a crucial process in the modern automotive, aerospace, manufacturing and electronic industries as it can produce high quality welds with an appreciable accuracy. Quality of the weld and joint efficiency is the most obligatory requirement. Present work focused on evaluating the mechanical properties for TIG welding aspects of SS 310 and MS materials. An attempt has been made to investigate the influence of various parameters namely welding current, diameter of filler rod and gas flow rate on the responses such as tensile strength, percentage elongation and Rockwell hardness. Welding is performed to join 1.5 mm thick SS 310 and MS plates which were then made to ASTM standard tensile specimens to carry out the tensile test. The mechanical strength is also evaluated using Rockwell hardness test. The results revealed that it has a maximum tensile strength of 424.312 Mpa welded with 60 Amps and having a gas flow rate of 6 Lit/min by employing a filler rod of diameter 2 mm. Moreover, the maximum hardness value of 61 HRB was reported with the sample welded with 40 Amps & 5 Lit/min of gas flow rate by using a 1.5 mm diameter filler rod.

Narrow-seam identification and deviation detection in keyhole deep-penetration TIG welding

A narrow-seam identification algorithm is developed to achieve seam tracking in keyhole deep-penetration tungsten inert gas welding (TIG). The welding images are captured by a high-dynamic-range camera and denoised by a bilateral filter based on a noise model analysis. The arc area is extracted as a fixed region of interest. Then, an improved Otsu algorithm and a parabolic fitting algorithm are used to obtain the centerline of the arc. The seam area is extracted as an adaptive region of interest based on a proposed HOG+LBP algorithm. Thereafter, a continuous single-pixel edge contour is extracted by the canny algorithm, and a proposed contour curvature evaluation method is used to obtain the corresponding pixel coordinates. After testing and analysis, the deviation can be reliably detected with an average measurement error within ± 0.04 mm. As a result, the algorithm proposed in this study can accurately identify the deviation during keyhole deep-penetration TIG welding, and has application prospects in the narrow-seam welding field.

TIG and MIG welding of high strength Cr-Mn and Cr-Ni alloyed austenitic stainless steel combinations

To substitute the relative expensive Ni alloying in stainless steels manganese alloying can be used. The welding of Cr-Mn alloyed steels however is not very well documented. In our current research two Cr-Mn alloyed austenitic stainless steel grades (1.4371 and 1.4376) were welded together via tungsten inert gas welding (TIG) and metal inert gas welding (MIG). Also for comparison different joint combinations with other Cr-Ni alloyed steel grades (1.4318 and 1.4301) were welded. The different steel grade showed quite the different behaviour in the joint combinations. The Mn-content in the base materials increased the weld metal hardness and tensile strength of the joint and decreased the fracture elongation values. Also the Mn-alloyed grades had significant higher grain coarsening in the heat affected zones than the Cr-Ni alloyed.

Thermal analysis of TIG welded Ti-6Al-4V plates using ANSYS

The exceptional properties of Titanium push it for research activities. A perfect and efficient welding of Titanium in similar and dissimilar manner is also a difficult task for manufacturing companies. Although there are so many ways for welding of Titanium but the most reliable method is Tungsten Inert Gas Welding (TIG). This study is based on the TIG welding and main focus is on temperature distribution. The aim of the study presented in this paper is to determine the temperature distribution profile by using effective and reliable method of simulation. Simulation was performed for Titanium-G5 alloy (Ti-6Al-4V), the most commonly used alloy of titanium. The used analysis was “transient analysis”. The concept of “Moving heat source” and “element birth & death model” technique is used to simulate welding Process. An experiment was also carried out on Titanium-G5 alloy (Ti-6Al-4V) for validation of ANSYS results. In this experiment a noncontact thermal image camera was used for temperature measurement. After the experiment and simulation it was found that temperature varies inversely with welding speed.

Characterization and Optimization of TIG welded supermartensitic stainless steel using TOPSIS

This study focuses on the optimization of process parameters in Tungsten inert gas welding (TIG) of supermartensitic stainless steel using Technique for Order Preference by Similarity to Ideal Solution Method (TOPSIS). Supermartensitic stainless steels are the best alternative to high-strength low-alloy steels which are mainly used in the applications related to the gasoline industry. Bead on plate TIG welding was performed based on taguchi L9 orthogonal array .The input process parameters considered for this work were current, voltage, travel speed, and shielding gas flow rate. The quality of the weld was analysed by measuring the bead width, depth of penetration and hardness of the weld. Multiobjective performance characteristics were optimised using TOPSIS. The Metallographic investigations for the best and worst weld with respect to bead geometry, hardness were also done. The end results of experimental investigation have proved that the weld quality can be enhanced effectively with the aid of the above said approach.

An Approach to Maximize Weld Penetration During TIG Welding of P91 Steel Plates by Utilizing Image Processing and Taguchi Orthogonal Array

P-91 is modified 9Cr–1Mo steel. Fabricated structures and components of P-91 has a lot of application in power and chemical industry owing to its excellent properties like high temperature stress corrosion resistance, less susceptibility to thermal fatigue at high operating temperatures. The weld quality and surface finish of fabricated structure of P91 is very good when welded by Tungsten Inert Gas welding (TIG). However, the process has its limitation regarding weld penetration. The success of a welding process lies in fabricating with such a combination of parameters that gives maximum weld penetration and minimum weld width. To carry out an investigation on the effect of the autogenous TIG welding parameters on weld penetration and weld width, bead-on-plate welds were carried on P91 plates of thickness 6 mm in accordance to a Taguchi L9 design. Welding current, welding speed and gas flow rate were the three control variables in the investigation. After autogenous (TIG) welding, the dimension of the weld width, weld penetration and weld area were successfully measured by an image analysis technique developed for the study. The maximum error for the measured dimensions of the weld width, penetration and area with the developed image analysis technique was only 2 % compared to the measurements of Leica-Q-Win-V3 software installed in optical microscope. The measurements with the developed software, unlike the measurements under a microscope, required least human intervention. An Analysis of Variance (ANOVA) confirms the significance of the selected parameters. Thereafter, Taguchi’s method was successfully used to trade-off between maximum penetration and minimum weld width while keeping the weld area at a minimum.

Three-dimensional simulation of 304L steel TIG welding process: Contribution of the thermal flux

In this study, we focus on the determination of the heat transfer properties in Tungsten-Inert-Gas welding (TIG) problem combining an experimental and a three-dimensional simulation approaches. Optimal conditions are used to weld stainless steel (304L) sheets in butt configuration. Both instrumental monitoring and metallographic investigation of the welded material are carried out. The modelling of the heat source is performed by a mobile Gaussian surface source exhibiting a bi-elliptical shape. This source is implemented in a three-dimensional finite element model to compute heat flux and temperature fields. The comparison between the experimental and numerical thermal cycles shows a fair agreement. Predicted temperature fields and heat flux distributions are discussed. Conversion of isotherms into microstructural information shows that the size of the fusion zone is four times smaller than the heat affected zone dimension. The metallographic analysis confirms the expected microstructural evolutions but highlights differences between observed and predicted extents of the heat affected zone.