A-TIG Welding Research Articles

Enhancing mechanical properties of dissimilar steel A-TIG weld joint by in-situ induction post-heating

An approach is proposed to enhance the mechanical properties (ductility and impact toughness) of dissimilar martensitic steel-austenitic stainless steel joint by ‘A-TIG welding with induction post-heating (A-TIG(I) welding)’. The A-TIG(I) welding mitigates the martensite formation and promotes the ferrite formation within the weld zone (WZ) by retarding the cooling rate (from 9.83 °C/s to 0.8 °C/s). Microstructural transformations enabled in achieving the improved ductility (44.9 %) without significant loss of strength (665.75 MPa). Overmatched impact toughness (103 ± 2) J of WZ was also obtained.

Penetration depth, phase balance and corrosion behaviour in activated TIG welding of UNS S32205

The aim of this research is to investigate the impact of a flux containing 80% TiO2 and 20% CeO2, under protective atmosphere (100% Ar, 98% Ar-2% N2, and 95% Ar + 5% N2) on penetration depth, phase equilibrium, and corrosion behaviour of autogenous A-TIG welds generated at constant current density. The reason for choosing cerium in the flux composition and nitrogen in the shielding gas is their effect on the phase balance of austenite and ferrite in this alloy. Metallography, ferritoscopy, and potentiometry were employed in the examination of the welds. The use of a two-component flux increased the penetration depth in TIG welding by up to 87%. Adding 2% and 5% nitrogen gas to the shielding gas in active TIG welding further increased the penetration depth to 117% and 130%, respectively. The results of ferritoscopic analysis reported the amount of austenite in the base metal and conventional TIG weld as 48% and 32%, respectively. However, the use of two-component flux increased the amount of austenite in the weld metal to 39%. Additionally, the addition of 2% and 5% nitrogen to the shielding gas in active TIG welding increased the amount of austenite in the weld metals to 60% and 76.6%, respectively. According to cyclic potentiodynamic polarization studies, active TIG welding with different nitrogen gas concentrations showed improved general and pitting corrosion properties in weld metals compared to conventional TIG welding. Consequently, weld metal resulting from active TIG welding with 2% nitrogen gas exhibited corrosion properties almost identical to that of the base metal.

AUGMENTATION OF DEPTH OF PENETRATION AND PRODUCTIVITY BENEFITS OF ATIG WELDS USING THE AHP

Weldability is an important issue in the fabrication of different grades of stainless steel used in industry. Tungsten inert gas (TIG) welding is widely used in industry for accurate and precision work, but lack of penetration is observed in this process even though current and welding speed can be varied considerably to increase heat input to obtain deeper penetration. Increased heat input adversely affects mechanical properties of the weldment. To overcome this, activated flux TIG welding is often used in industry to achieve higher depth of penetration with relatively less heat input. In this study, activated flux TIG welding is used with input variables such as heat input, welding speed and pulse frequency. The chosen base metal is SS 304L stainless steel, and a hybrid flux mixture containing fluxes of SiO2, MnO2 and MoO3 in a ratio of 1:1:2 is used to obtain the desired depth of penetration. Nine experimental runs are conducted to obtain the optimum depth of penetration. Heat input values are 2.767 kJ/mm, 1.470 kJ/mm and 1.281 kJ/mm and pulse frequency is 160 Hz, 120 Hz and 80 Hz. Welding speed varies from 0.5 mm/s to 1.18 mm/s. A maximum depth of penetration of 4.42 mm is achieved with a heat input of 2.767 kJ/mm, welding speed of 0.5 mm/s and pulse frequency of 160 Hz. The reversed Marangoni effect and arc constriction effect are the mechanisms responsible for the deeper penetration in ATIG welding. In this research, a multi criteria decision making tool, the Analytical Hierarchy Process (AHP), is used to validate the optimum value obtained. The optimal values obtained in the research are in good accordance with those obtained using the AHP. The outcome of the present investigation indicates the applicability of ATIG welding for joining large thickness of stainless steel flats to give enhanced productivity by reducing the number of weld passes.

Welding investigation of Hastelloy C-276 and parametric optimization using integrated MRA-TLBO algorithm during A-TIG process

A-TIG welding is a modified form of GTAW process that has become popular due to its ability to create high-quality welded joints with minimal cracks and distortion. This technique is commonly used to join various metals, including stainless steel, aluminum, titanium, and nickel alloys like Hastelloy C-276, which is used in fabrication of complex components across marine, nuclear, aerospace, and chemical industries. In this investigation, A-TIG welding of Hastelloy C-276 was studied using three parameters - welding current, welding speed, and gas flow rate - at three distinct levels. The impact of these parameters were analyzed on two responses, namely penetration depth and width of weld. Macrostructural investigation, sensitivity analysis, and parametric studies revealed that welding current (I) had the most influence, followed by speed of welding (S) and flow rate of gas(G). Full quadratic multiple regression analysis-based models were developed for both responses, which were found to be suitable with a higher coefficient of determination and an average percentage error of 2.165% and 2.624%, respectively. Additionally, a teaching learning based optimization algorithm was integrated with these models to identify the most effective A-TIG parameter combination for higher penetration depth and lower weld width. The MRA-TLBO integrated approach resulted in an optimal parametric combination of I (170A), S (180 mm min−1), and G (11.37 l min−1) that resulted in a penetration depth and weld width of 4.503 mm and 4.684 mm, respectively. Validation at this optimal setting showed an improvement of 3.365% and 1.284% for weld width and penetration depth, respectively, suggesting the robustness of the developed methodology.

Usporedba topitelja za ATIG zavarivanje i njihov uticaj na mehaničke osobine

The application of conventional electric arc welding in argon protection (TIG welding process) has limited possibilities. These limitations are primarily related to the thickness of the welded material and the need to prepare the groove for their welding. Overcoming these limitations in TIG welding was done by using activating flux, so the procedure was named ATIG (A-TIG) welding. The paper presents the results of research into the application of activating fluxes in welding austenitic stainless steel 316L with a thickness of 6 mm. By using the BC-31 and QuickTIG melters of different chemical bases, we compare the mechanical properties of the welded joints, as well as with the welded joints of the same material obtained using the conventional TIG procedure. The results show that the best mechanical properties are possessed by welded joints realized by the ATIG process using a mixture of activating fluxes BC - 31 (50%) and QuickTIG (50%) (green + white flux).

A Machine Learning Approach for Prediction of Surface Temperature of the Weld Region in A-TIG Welding

A Machine Learning Approach for Prediction of Surface Temperature of the Weld Region in A-TIG Welding

Numerical Simulation of the Effect of Fusion Welding Processes on Residual Stress in Stainless Steel Pipe Weld Joints Used in Fast Reactors

The main structural material used in the building of Fast Breeder Reactors (FBR) is stainless steel of type 316L(N). Finite Element Model (FEM)-based simulations were carried out to understand the effect of various welding processes on the residual stresses induced in 316L(N) stainless steel primary sodium-carrying pipes with an inner diameter of 208 mm and a wall thickness of 5.6 mm. The welding processes considered include multi-pass Tungsten Inert Gas (TIG) welding, A-TIG, laser, hybrid laser-TIG, and Hybrid laser-Metal Inert Gas (MIG). First, single or hybrid heat sources are chosen based on the welding process, and then weld bead profiles obtained during simulation are made to match with that of the actual weld bead profiles obtained during experiments. Then, the optimised heat source is employed for the thermal analysis. The thermal analysis output is then successively linked and provided as input to the mechanical analysis, which uses an isotropic hardening model to predict hoop and axial residual stresses in pipe weld joints. The results show that the A-TIG weld joint exhibited lower hoop stress (165 MPa at inner diameter and -2 MPa at outer diameter) in comparison with that of the other weld joints. The lower residual stress is attributed due to the straight-sided weld bead, lower peak temperature, and slower cooling rate of the A-TIG welding. Therefore, A-TIG welding is recommended among the chosen fusion welding processes for welding of 316L(N) stainless steel primary sodium carrying pipes to minimise the residual stresses and mitigate the premature failure of the pipe weld joints.

Process parameters based machine learning model for bead profile prediction in activated TIG Welding using random forest machine learning

The bead profile in the activated tungsten inert gas welding process depends on process parameters and flux composition. Using a conventional statistical-based model, the correlation of these input parameters with the bead shape geometry is complex. Therefore, machine learning-based techniques were implemented to predict the bead shape geometry, that is, penetration (D), width (w), and D/w ratio in the A-TIG welding process of austenitic stainless steel. Random forest regression and classification models were implemented to predict bead shape geometry in the A-TIG welding process. Based on the results, classification-based modeling was appropriate for predicting the bead profile. In addition, the correlation of the process parameters and flux composition with the bead profile was established.

Experimental investigation of the flux-assisted TIG weldment of super duplex stainless steel

The focus of the current article is on the microstructure and behavior of the autogenous joints produced by ATIG welding on 6 mm thick super duplex stainless steel plates. The blending of two mostly used metallic oxides TiO2 and SiO2 is used as flux materials in the varied ratio to carry out ATIG welding. The essential processing requirements like welding current maintained at 160A and argon gas flow velocity maintained at 16 L/minute are used for the weld joint experiment. The complete study of weld morphology, various zone of weld region, weld interface microstructure, and mechanical and corrosive characteristics are all studied in this investigation. In comparison to other varied ratios of bicomponent flux-assisted welded joints, the bicomponent flux compromised of 50% of TiO2 and 50% of SiO2 assisted weldment showed excellent tensile strength, impact strength, and corrosion resistance.

Effect of TIG and activated flux TIG welding processes on weld bead geometry, microstructure, and hardness of SAF 2507 grade super duplex stainless steel joints

Tungsten inert gas (TIG) welding is frequently used to fabricate super duplex stainless steel weldments due to its superior mechanical qualities and attractive appearance in contrast with other arc welding techniques. The broad use of TIG welding remains constrained despite all of its advantages. Thus, the process of activated flux tungsten inert gas (A-TIG) welding is created. In the current study, ATIG welding with different oxide fluxes is used to execute bead-on-plate welding on 6 mm thick super duplex (SS) SAF 2507 grade. The TIG and ATIG processes are used for bead-on-plate welding, and the macrostructure, microstructure, and mechanical features of super DSS weld beads are analysed. When different oxide fluxes are used, the A-TIG technique achieves a greater depth of penetration and a narrower weld bead width than the standard TIG process. SiO2 flux with ATIG welding gives the highest depth of penetration (5.42 mm) among all other fluxes used. Also, A-TIG welding using SiO2 flux has a finer grain structure and a higher hardness value than other fluxes. The primary microstructure in the A-TIG weld zone was austenitic, but delta ferrite was still present.

Hardness Analysis of Aluminium 5083 A-TIG Welding Due to The Effect of Active Flux and Current

Aluminium allow has been widely used recently due to their high strength to mass ratio, good formability and high corrosion resistance have a wide range of applications in aerospace, ship-building and railway industries. The 5083 series aluminum is the most widely used due to good strength and corrosion resistance properties. Tungsten Inert Gas Welding (TIG welding) is the most common welding method for aluminum alloys. This research was conducted A-TIG welding on 150 x 100 x 8 mm of 5083 aluminium and added by oxide powder (MgCl2 and TiO2) as active flux and various of current consist of 100, 130, and 160 A. The result of this research was obtained that the deepest penetration was 4.94 mm with TiO2 active flux and the current of 160 A, the highest hardness came from weld metal which using MgCl2 as an active flux with 100 A of current with 69.80 HVN. The hardness was increased by adding magnesium due to effect of it could be increased grain coarse. The lowest hardness was on weld metal with TiO2 active flux with 160 A of current due to the maximum heat input which decreased the hardness The recrystallization was occurred due to increase of heat input, so did the grain growth. The coarse grain which caused the decreasing of hardness was affected by the increase of heat input.

Experiment analysis of A-TIG welding and comparison between TIG, Double-TIG, and A-TIG of Hastelloy C-276

The present study Hastelloy C276 welding performs using tungsten inert gas (TIG) and activated flux-TIG (A-TIG) welding technique. A nickel (57%), molybdenum (15 to 17%), chromium (14.5 to 16.5%), Iron (4 to 7%) and tungsten (3 to 4.5%) alloy called Hastelloy C-276 has outstanding all-around corrosion resistance and is easy to work with. Reverse marangoni and the arc concentration effect both considerably increased the depth of penetration during ATIG welding with SiO2 flux. The Macro structural analysis and hardness survey of weld bead profile of TIG, Double TIG and ATIG performed and find out that ATIG welding have greater depth of penetration and high hardness value than normal TIG welding. A TIG welding produced better hardness; the difference in hardness values was about 8.45%.

Weld Cladding, ATIG Welding and Wire Arc Additive Manufacturing: Some Emerging Areas of Welding Research

Weld Cladding, ATIG Welding and Wire Arc Additive Manufacturing: Some Emerging Areas of Welding Research

Welding investigations on mechanical property and microstructure of TIG and A-TIG Weld of Hastelloy C-276

Hastelloy C-276 is a nickel-based alloy with high strength and corrosion resistance at cryogenic to high temperatures. The issue of Hastelloy C-276 shallow penetration by Tungsten Inert Gas (TIG) welding was addressed in the current investigation by applying A-TIG welding with variable oxide flux. In the current investigation, constant welding conditions were used to perform TIG and A-TIG welding using SiO2, TiO2, and a 50% mixture of SiO2 + TiO2 flux. The weld bead width and depth of penetration of the weld bead profile were measured, and the mechanical and metallurgical properties of the weld metal was investigated. SiO2 flux attained the highest D/W ratio and depth of penetration during A-TIG welding when compared to other fluxes used. A-TIG welding using SiO2 flux improved the depth of penetration and the D/W ratio by 118% and 263%, respectively, in comparison with conventional TIG welding. Additionally, the A-TIG welded sample with SiO2 flux had an ultimate tensile strength of 738.295 MPa and a percentage of elongation of 52.75%.

Evaluation of welding-induced residual stress and distortion in A-TIG welding of duplex stainless steel

Applying non-uniform heat in welding causes residual stress and distortion, which affects the life of components. In the present study, the residual stress and distortion of Duplex 2205 stainless steel in A-TIG welding were investigated numerically and experimentally. The optimal welding parameters for highest penetration depth in welded samples were obtained experimentally. Uncoupled thermal-mechanical analysis using ABAQUS 2017 software has been done. Goldak's parameters were measured by empirical tests. The results include simulation diagrams of four samples consisting of the optimal sample without flux powder and three samples with the highest penetration depth. The simulation results show that the sample without flux has a higher maximum temperature and lower welding-induced distortions. The efficiency used in this research changes using and not using powder; it is concluded that, in similar conditions in A-TIG welding, fewer values of parameters are needed to achieve the appropriate result comparing conventional TIG. The efficiency of workpieces with flux should be considered about 20% lower to have similar results to the conventional TIG. The numerical modeling results showed a good agreement with experimental data both for temperature distribution and welding-induced residual stress and distortion. The distortion in the pieces with conventional TIG welding has increased to 11% at the farthest point from the welding line. The error obtained from comparing the results in residual stress is between 12 and 34%.

Effect of Longitudinal Magnetic Field on the Microstructure and Properties of A-TIG Welding with Different TiO2 Coating Amounts

In order to improve the poor weldability and low quality of welded joints during the welding of magnesium alloys, a longitudinal magnetic field is introduced in the welding process of A-TIG welding with a fixed magnetic field frequency (30 Hz) and magnetic field current (1.5 A). Experimental analysis is performed on the effect of the magnetic field on the microstructure and mechanical properties of welded joints under different TiO2 active agent coating amounts. The results show that the grain size tends to decrease and then increase with the increase in the active agent coating under the magnetic field. This is mainly because the active agent changes the arc morphology, which in turn affects the melt pool motion. The Lorentz force generated by the longitudinal magnetic field acts on the molten pool and will have an agitating effect on the pool. Both the magnetic field and the active agent are convective to the melt pool, and when the magnetic field and the active agent act together will further enhance the convective effect. However, when the active agent is too thick, it will affect the fluidity of the molten pool during welding and reduce the quality of the welded joint. Under the action of magnetic field, when the active agent coating amount is 3 mg/cm2, the grain size is the finest and the mechanical properties are the best. At this time, the tensile strength was 292 MPa, elongation was 11.2%, and hardness was 78.9 HV in the weld zone and 77.8 HV in the heat-affected zone. Further analysis of the melt pool change and grain refinement mechanism under the combined effect of the magnetic field and active agent revealed that the magnetic field promotes the solidification of the second phase in the weld tissue, but the effect on the heat-affected zone is not obvious. The addition of the magnetic field was found to refine the grains by EBSD testing, reducing the average grain size by 1.43 μm. This indicates that the introduction of the magnetic field in the A-TIG welding process improves the mechanical properties and microstructure of the welded joint, which is conducive to solving the problem of poor weldability in the welding process of magnesium alloys.

Application of A-TIG welding for improving the technology of manufacturing and repair of units of gas turbine engines and installations from titanium alloys

The Paton Welding Journal, 2022, №10. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

PENGARUH JENIS ACTIVATED FLUX DAN VARIASI KUAT ARUS PADA PENGELASAN A-TIG DISSIMILAR MATERIAL TERHADAP KEDALAMAN PENETRASI, KEKERASAN, STRUKTUR MIKRO DAN LAJU KOROSI

The TIG welding process has shallow penetration. The addition of activated flux can increase the depth of penetration of the weld, which is called A-TIG welding, so this study to analyze the effect of the activated flux type and current on the depth of penetration, hardness, microstructure, and corrosion rate. This study used SUS 304 and A36 materials with a thickness of 6 mm which are welded using the A-TIG welding process with variations of activated flux Fe2O3, Cr2O3 and variations in the current strength of 100 amperes and 120 amperes. To find out the results of these variations, this study was tested by macro, hardness, microstructure, and corrosion rate tests. The results of the study on variations in the type of activated flux and variations in current resulted penetration depth of 3.6 mm found in activated flux Cr2O3 with 120 amperes and penetration depth in activated flux Fe2O3 with a value of 2.43 mm on 100 amperes. Then the highest hardness value was found in activated flux Fe2O3 and 120 amperes with a value of 471.48 HVN, and the lowest is in Cr2O3 ampere 100 with a value of 398.16.HVN. The micro test results in a phase change from pearlite, ferrite, and austenite to martensite in the weld metal. And to test the corrosion rate on activated flux Fe2O3 and a current of 120 amperes with a value of 0.24931 mm/year, the activated flux Cr2O3 and a current of 100 amperes with a value of 0.090114 mm/year.

Achieving Favourable Depth of Penetration and Productivity of ATIG Welds Utilising the AHP

Achieving Favourable Depth of Penetration and Productivity of ATIG Welds Utilising the AHP

Welding investigation on penetration and mechanical property of AISI 201 during A-TIG welding

Austenitic Stainless Steel has improved mechanical properties and great corrosion resistance thereby it is extensively used in fabrication industries. The aim of our work is to compare the mechanical property and macrostructural of TIG and A-TIG welding process on Nitrogen alloyed stainless steel and find out the best oxide flux to be used before welding to improve the macrostructure, penetration, weld width, and tensile strength of butt joint. Five dissimilar fluxes i.e. SiO2, MnO2, TiO2, ZnO and CaO were used during A-TIG welding. Experiments were performed at same welding speed but at different welding current in both TIG and A-TIG welding. In the whole process SiO2 and TiO2 helps to get full penetration of 5 mm at 200 A welding current while least penetration of 3.16 mm obtained during TIG method. Welding parameters giving the best penetration profile was chosen to perform welding on butt joint for assessment of strength. Test coupon of TiO2 had greater strength (698 N mm−2) as well as percentage elongation (34.5).