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This article presents a study on optimizing Tungsten Inert Gas (TIG) welding on mild steel (SPCC-SD/JIS G3141) with varying thicknesses of 0.6 mm and 0.8 mm. Automobile bodies commonly utilize mild steel with a material thickness ranging from 0.6 to 0.98 mm. The objective of this study was to ascertain the upper limit of tensile-shear strength that can be achieved by utilizing the specific parameters utilized in TIG welding. This study utilizes a three-level experiment and incorporates three input variables in the Taguchi experimental optimization method. The advantage of this approach lies in its ability to yield comprehensive outcomes while minimizing expenses, as it can be adapted to the resources available. An additional benefit is that this approach can be implemented in a multitude of industrial situations.The study's input variables are welding current, argon gas flow rate, and electrode diameter. Utilizing a continuous flow of argon gas of 12 LPM (liter per minute), a welding current of 55 A, and an electrode diameter of 1.6 mm, the maximum mean T-S strength of 3457.13 N was achieved. The ANOVA revealed that the flow rate, welding current, and electrode diameter had a per cent contribution of 50.07%, 26.89%, and 23.04%. The flow rate was the parameter with the most significant impact on the influential variable. The welding current and the electrode diameter do not significantly affect the response. The findings indicate that by adjusting the parameters to the optimal level determined by the Taguchi method, the S-N ratio for T-S strength increases by 9.30%, and T-S strength increases by 12.42%. The findings of this study offer a thorough comprehension of enhancing the TIG welding approach and can be further refined by incorporating additional variables.

High-quality thick Ti-6321 titanium alloy welded joints were obtained by tungsten inert gas（TIG）welding， the microstructure changes of fusion zone， heat affected zone and base metal zone of the welded joints before and after annealing were compared.The impact properties， fracture toughness and tensile properties were tested， and which were compared with the base metal. The results show that the microstructure of the fusion zone before annealing is composed of coarse β columnar grains with fully grown intragranular acicular martensite α′ phase， and heat affected zone consists of equiaxed structure with β matrix and primary α phase， martensite α′ phase precipitates in β matrix.After annealing， the martensite α′ phase in β matrix of the fusion zone and heat affected zone completely transforms into secondary α phase. The impact toughness， fracture toughness， tensile strength and elongation of Ti-6321 titanium alloy welded joints are 80.3 J/cm2， 113.00 MPa·m1/2， 873 MPa and 9%， respectively， which are 104.7%， 84.1%， 100% and 67.7% of the base metal，respectively. Compared with the fracture of the base metal， the impact fracture of welded joints has a coarser stepped surface and smaller equiaxed dimples， while the fracture surface of toughness is more flat and the fatigue crack propagation zone is narrower.

The tensile properties of 2219-T8 aluminum alloy TIG welding joint were significantly affected by the microstructure, local mechanical properties and weld geometry. This paper proposed a machine learning model to predict and optimize the tensile properties of 2219-T8 aluminum alloy TIG welding joint. The relationship between tensile strength of joint and weld geometry, weld zone and partially melted zone (PMZ) properties was developed by Kriging model combining whale optimization algorithm (WOA). This surrogate model demonstrated a high precision, with R2 = 0.952 and RMSE=3.77 MPa. The surrogate model, which also served as a welding process guide, was utilized to determine the ideal weld geometry corresponding to various weak zone properties. By applying the optimization process based on the surrogate model, the optimized joint strength coefficient reached 70 %, and elongation exceeded 4 %. The collaborative regulation mechanism of geometry and property was also discussed.

The metallurgical changes and micro defects after welding can influence the mechanical property, corrosion resistance and dimensional stability of the stainless steel wielding joints. It is necessary to explore an effective post-welded method to improve the service performance for stainless steel welding joints. Furthermore, the essential mechanism between microstructure changes and macro-property variation during this process needs deep reveal. Therefore, this paper aims at investigating the effects of different post-weld treatments including naturally aging, artificial aging and cryogenic treatment on the residual stress and mechanical properties of 304 stainless steel weldments. The microstructure evolution was also studied to reveal and establish the microstructure-performance relationship. The results showed that the distribution of residual stress was most uniform with lowest magnitude (decreased by up to 49%) after cryogenic treatment. At room temperature, weldments subjected to the three post treatments showed similar mechanical properties. At cryogenic temperature, cryogenic treatment exhibited an outstanding role on maintaining the mechanical properties of weldments. By contrast, the mechanical properties were obviously reduced by artificial aging. The transformation of δ-ferrite and the carbide precipitation in grain boundaries are the main reasons for the decrease of mechanical properties after artificially aging. Welding process was able to cause the transfer of the alloying elements and decrease the stability of austenite. Consequently, martensitic transformation can be induced during cryogenic treatment. The new formed martensite resulted in the refined microstructure and high mechanical properties of weldments, and also the release of residual stress after welding.

The attractive mechanical properties of 7075 alloy, such as its high strength-to-weight ratio and fracture toughness, have received special attention in the automotive and aerospace industries. However, welding as a fabrication process has a detrimental effect on this alloy’s properties which affects its mechanical performance. In this work, to compensate for the loss in mechanical properties caused by welding, proper heat treatment operations are adopted. To this end, 1.5 mm AA7075 sheets were first preheated and butt welded using the gas tungsten arc welding process. The welded sample was solution heat treated, quenched, and then artificially aged. Microhardness tests showed an increase of hardness in all zones of the aged specimen compared to those of the original welded blank before heat treatment. A maximum microhardness value of 180 HV was recorded in the heat-affected zone of the aged specimen. In addition, elongation at break, and strength (yield, tensile, and fracture) of the original welded blank increased by about 50% after the artificial aging operation.

The finite volume method (FVM) was used to model a tungsten inert gas (TIG) arc welding process. A two-dimensional axisymmetric model of arc plasma integrating fluid–solid coupling was developed by solving electromagnetic and thermal equations in both the gas domain and the solid cathode. In addition, two additional coupling equations were considered in the gaseous domain where the arc is generated. This model also included the actual geometry of torch components such as the gas diffuser, the nozzle, and the electrode. The model was assessed using numerous numerical examples related to the prediction of the argon plasma mass fraction, temperature distribution, velocity fields, pressure, and electric potential in the plasma. A new linearization method was developed for the source term in the energy conservation equation, allowing for the prediction of Joule effects without artificial conductibility. This new method enhances the efficiency of the classical approach used in the literature.

Abstract An important goal in a number of optimization studies is a high-quality weld joint. Thermal analysis of AISI 1020 low carbon steel plate agglutinated by gas tungsten arc welding technique was carried out using S 2021 version. With SOLIDWORKS Premium, the simulation was run. The simulation was performed using the Thermal Simulation programme with 20 weld runs. With the findings of the initial study serving as a sensor, a design study was conducted. A total of 15 runs were completed, and the weld dilution and thermal conductivity responses were available. A range of welding temperatures including 3397 to 3688 °C were experimentally applied in the joining process of AISI 1020 low carbon steel plate of 10 mm thickness, and a strain gauge indicator was used to measure the thermal stresses induced in the steel plate. However, minimum and maximum weld dilution values of 73.1 and 46.8% were obtained with FEM at an input of arc heat of 66.4 and 37.2 J/mm, while the minimum and maximum weld dilution values of 71.55 and 45.5% were computed using experimental approach at the same heat input. On the other hand, maximum and minimum weld dilution of 71.55 and 44.5% were computed from experimental process at minimum and maximum welding current of 199.77 and 250.23 A, while 73.1 and 46.8% were obtained for the maximum and minimum weld dilution through FEM procedure at the same welding input variables. Hence, gas tungsten arc welding input parameters should be properly selected and controlled during welding operation, in order to minimize thermal effects and welding flaws such as high dilution rate.

Nd: YAG Laser and Tungsten Inert Gas (TIG) welding processes are the most promising joining techniques used for stainless steel (SS) alloys due to their significant weld characteristics. In this study, the effect of two process parameters (weld power and travel speed) on the mechanical properties (ultimate tensile strength and microhardness) of the weldment is investigated. Two different machine learning techniques, namely Adaptive Neuro-Fuzzy Inference System (ANFIS) and Unified Convolutional Neural Network (UCNN) are also evaluated for prediction of mechanical properties and defect detection through the image processing technique, respectively. A correlation has been performed between these two machine learning approaches with the experimental values. The training data sets are developed for the machine learning techniques, and the obtained results of (ANFIS) and (UCNN) models are related to the actual experimental values. The output of both developed models (ANFIS & UCNN) showed a good agreement with the actual experimental test results. The predicted tensile and microhardness values from the (ANFIS) model were found to greatly agree with the Peak Signal-to-Noise Ratio (PSNR) values from the (UCNN) model. However, owing to the increase in the applications of welding processes in industries, the utilization of machine learning techniques would be more efficient when compared with the other traditional methods that are being adopted.

The 7075-T6 aluminum (Al) alloy is a high-strength material with great application potential. However, the tensile strength and elongation of its arc-welded joints are severely reduced compared to the base metal (BM), with only 57.3% and 14.4% of the BM values, respectively. To improve both strength and plasticity simultaneously, a novel post-weld composite treatment process combining solution treatment, partial rolling, and natural aging treatment (SRA) was proposed. The SRA process enhanced the strength and elongation of welded joints to 84.5% and 83.1% of the BM, respectively. In different regions of the joints, the SRA process involved different strengthening mechanisms, including stronger work hardening in Region I, η′ phase precipitation and weaker work hardening in Region II, and refinement of the η’ and η phase in Region III. The SRA process also improved the formability of the welded joints from 62.5% to 87.5% of the BM. In addition, the SRA process increased the median fatigue life of welded joints by a factor of approximately 2–6. This was achieved by increasing the strength and microhardness of the fusion zone, which, in turn, reduced the number of fatigue crack sources and shifted crack sources from the surface to subsurface regions.

In batch operation, most industries require engineers to maintain low hardness on the welded parts, particularly for low carbon steel. This article focuses on tungsten inert gas (TIG) welding performed on 0.90 mm of a C67 grade sheet by varying different welding parameters such as current, velocity, and temperature. Samples were collected from the tool side, mid-wall, and operator side for metallographic and micro-hardness examinations considering various parameters. Without post welding heat treatment (PWHT), the welded parts were quenched at room temperature, while with PWHT the welded parts were kept at 710 ℃ for 99 s after welding, and subsequently, the samples were cooled slowly by air at ambient temperature. An increase in hardness was registered in either the fusion zone or melted zone, with decrements in the heat affected zone (HAZ) for both procedures. When the the welding was performed without PWHT, a martensitic and bainitic microstructure was noticed in the melting zone (MZ) and HAZ, respectively. In contrast, a bainitic microstructure was observed in either the melting or heat affected zone in the welding with PWHT. Metallographic images revealed crack propagation when welding was performed without PWHT. A larger HAZ was noted in the welding sample with PWHT, and hardness was also relatively lower compared the samples without PWHT. There was no significant difference in hardness among the samples taken from tool side, mid-wall, and operator side for both procedures. Finally, the lowest microhardness (265 HV) was found in the MZ when the welding was carried out with PWHT employing a 90 A current and 10 mm/s velocity.

The Ti-4Al-2V (wt. %) titanium alloy has garnered widespread applications across diverse fields due to its exceptional strength-to-weight ratio, high toughness, specific strength, and corrosion resistance. The welding of Ti-4Al-2V titanium alloy components is often necessary in manufacturing processes, where the reliability of a welded joint critically influences the overall service life of these components. Consequently, a comprehensive understanding of the welded joint’s microstructure and mechanical properties is imperative. In this study, Ti-4Al-2V titanium alloy was welded using multi-layer and multi-pass TIG welding techniques, and a detailed examination was conducted to analyze the microstructure and grain morphology of each microzone of the welded joint. The results revealed the presence of an initial α phase and a secondary lamellar α phase in the heat affected zone (HAZ). Meanwhile, the fusion zone (FZ) primarily comprised a coarse secondary α phase and a small amount of an acicular martensitic α’ phase. Both the recrystallization zone and the superheated zone exhibited a distinct preferred orientation, with grains smaller than 10 μm accounting for 65.9% and 55.1%, respectively. To assess the mechanical properties of the various microzones and the typical microstructure within the welded joint, nanoindentation tests were performed. The results indicated that the recrystallization zone possessed a higher nanohardness (3.753 GPa) than the incomplete recrystallization zone (3.563 GPa) and the superheated zone (3.48 GPa). Among all the microzones, the FZ exhibited the lowest average nanohardness (3.058 GPa). Notably, the basket-weave microstructure demonstrated the highest average nanohardness, reaching 3.93 GPa. This was followed by the fine-grain microstructure, which possessed a slightly lower nanohardness. The Widmanstätten microstructure, on the other hand, exhibited the lowest nanohardness among the three microstructures within the HAZ. Therefore, the basket-weave microstructure stands out as the most desirable microstructure to achieve in the welded joint. In summary, this study provides a comprehensive characterization and analysis of the microstructure and properties of Ti-4Al-2V titanium alloy TIG welds, aiming to contribute to the optimization of the TIG welding process for Ti-4Al-2V titanium alloy.

Welding is an important manufacturing process for joining complex parts. Despite their widespread use, there exist some drawbacks in the existing liquid-state (e.g., formation of undesirable heat-affected zones around weld area) and solid-state (e.g., high equipment and tooling costs, low production rates, and difficulty in joining intricate geometries) methods. These limitations continually spur the search for new joining processes to improve existing welding methods or develop new ones that circumvent these limitations. To provide a “greener” and low-cost alternative to the traditional welding processes that often produce “soft” heat affected zones (HAZs), we develop and evaluate the expansion of cold spray process—a solid-state high-velocity particle deposition process—to solid-state welding, a process we term cold spray welding (CSW). Using well-defined processing parameters, we cold spray welded (CSWed) AA 6061-T651 plate and compared the results with Tungsten inert gas (TIG) welded counterpart. Although TIG-welded samples exhibit higher tensile properties than CSWed samples (at least based on the CS processing parameters used in this study), our findings show that CSW indeed circumvents major drawbacks in traditional welding processes, including negligible microstructural alterations and the inhibition of deleterious phase transformation and suppression of deleterious HAZ. The examination of CSWed parts reveals low yield strength is connected to ubiquitous microvoids that are formed due to lack of metallurgical bonding; these microvoids act as microcrack initiation sites. We proceed to establish a failure mechanism in the CSWed part to provide direction for future optimization.

Welding is widely used in the aerospace, naval and automotive industries. Since high temperatures are involved in this process, solid state metallurgical changes are expected. These metallurgical changes can induce deformations and residual stresses in welded parts. The objective of this work is to develop a finite element calculation code, under the MATLAB environment, to predict the evolution of the various metallurgical transformations during TIG welding of C50 steel plates. In the proposed calculation procedure, we used Leblond’s equation and Waeckel’s model to characterize the metallurgical transformations during respectively heating and cooling stage. We also taken into account the effect of austenitic grain size on metallurgical transformations evolution. Thermal properties are introduced according temperature and phase proportions present during welding operation. Simulation results show that the metallurgical structure in the heat affected zone (HAZ) is largely related to welding thermal power and the plate preheating temperature. We compared simulation results to experimental measurements and the efficiency of the developed computational code was confirmed.

This work aimed to compare the quality and properties of the welded joints of AMg6 aluminium alloy produced via conventional TIG welding with the properties of those produced with flux backing tape. This study focussed on the relative length of oxide inclusions (Δoi) and the amount of the excess root penetration (hroot) of the AMg6 alloy weld beads. The results show the influence of the thickness of the flux layer of the backing tape on the formation and quality on the AMg6 alloy welds, along with the effect of flux backing tape and edge preparation on the mechanical properties of the 6 and 8 mm thick welded plates. In accordance with the results obtained, the joints produced by means of TIG welding with flux back backing tape and without edge preparation have higher mechanical properties. Moreover, the TIG welding of AMg6 alloy using flux backing tape reduces the total welding time by 55%, reduces filler wire consumption by 35%, reduces shielding gas consumption by 43% and electricity consumption by 60% per 1 linear meter of the weld line.

This study investigates the optimization of process parameters in TIG welding of EN31 steel alloys, incorporating nano-enhanced materials to improve performance in sustainable manufacturing and energy-efficient applications. The three key input variables considered are welding current (CT), welding speed (WD), and gas flow rate (GF), while tensile strength (TS) and hardness (HS) are taken as output responses. The experiment was designed using the Central Composite Design (CCD) under the Response Surface Methodology (RSM) framework, with 20 experiments conducted. Nanoparticle (TiO2 & B4C) were coated with EN31 steel to enhance chemical reactions, improve weld quality, and promote energy efficiency. Results indicate that the optimal conditions for tensile strength (TS) were achieved at 120 Amps CT, 70 mm/min WD, and 11 lpm GF. For hardness (HS), the optimal conditions were 100 Amps CT, 70 mm/min WD, and 11 lpm GF. Analysis of variance revealed that the welding current (CT) significantly impacts both TS and HS, while the integration of nano materials further improved these mechanical properties by enhancing microstructural refinement and energy efficiency. The experimental data closely aligned with the normal probability plot, confirming the reliability of the results. This study highlights the potential of nano-enhanced TIG welding as a sustainable solution for improving the mechanical properties of steel alloys while promoting energy-efficient manufacturing practices

Solidification cracking is a long-standing issue in fusion welding of high-strength aluminum alloys like Al7075, imposing limitations on their aerospace and automotive applications. The current study introduces a novel adapted approach in solidification crack elimination by incorporating TiC nanoparticles into the fusion zone using a filler paste as an easier to fabricate alternative to filler metals investigated so far. To assess the weldability of the proposed method, 3-mm thick Al7075 sheets were TIG welded (i) autogenously without any TiC nanoparticles (autogenous), (ii) heterogeneously using 1 vol.% TiC-nanoparticle enhanced Al7075 filler metal (heterogeneous filler metal), and (iii) heterogeneously using an in-house fabricated Al7075 paste containing 1 vol.% TiC nanoparticles (heterogeneous filler paste). Macroscopic analysis of weld specimens proved that both heterogeneous welding approaches effectively eliminated solidification cracks. This was confirmed by Houldcroft solidification susceptibility index deduction tests that demonstrated a strong reduction in solidification crack susceptibly in all heterogeneous joints as compared to the autogenous joint. Microstructural analysis confirmed the transformation from columnar to equiaxed grain morphology in the fusion zone as crucial factor in crack elimination. Overall, the proposed filler paste method represents a highly cost-efficient approach for eliminating solidification cracks in TIG joining of difficult to weld aluminium alloys.

In this study, response surface methodology (RSM) was employed to optimize the welding parameters’ effects on mechanical properties of dissimilar welds between Cr-Mo steel grade (P11) and austenitic stainless steel (AISI 316LN). To determine the best welding parameters, variance analysis (ANOVA), desirability function, and perturbation analysis were used to create regression models and identify the significant parameters influencing tensile strength and hardness gaps in the weld joints. The results indicated that welding speed is the most significant parameter affecting both the austenitic hardness gap and tensile strength, while gas flow has the most significant impact on the hardness gap of Cr-Mo steel. Furthermore, welding speed positively influences the mechanical properties of dissimilar weld, whereas welding current has a slight negative effect on tensile strength. The optimum welding parameters were found to be 130 A for welding current, 70 mm min ^−1 for welding speed, and 13 l min ^−1 for welding gas flow, resulting in hardness gap values of 18.10 HV (Stainless steel side), 27.38 HV (Cr-Mo steel side), and a tensile strength of 453.90 MPa. The optimum parameter effect is concentrated at the weld interfaces between the fusion zone and the heat-affected zone. This effect led to limitations in grain coarsening, a reduction in the martensite and delta ferrite phase percentages, a slight increase in the bainite ratio, and a decrease in carbide precipitations. As a result, a homogenization of strain distribution in the optimum weld was achieved, leading to ductile fracture in Cr-Mo steel.

The AISI 316 L stainless steel was welded using Tungsten Inert Gas (TIG) welding, utilizing ternary shielding gases Argon (Ar), Helium (He), and Nitrogen (N _2 ). This study aimed to assess the effects of these ternary shielding gases on the microstructure, bead profile, and bead appearance. It provides a comprehensive grasp of welding parameters’ interplay with shielding gas compositions, enabling engineers to make informed choices that significantly influence the excellence, productivity, and lastingness of the welding process. The Taguchi L-27 approach was employed, incorporating different contents of N _2 (2.5 vol. % to 7.5 vol. %) and He (10 vol. % to 30 vol. %) within the Ar shielding gas composition. Additionally, welding current intensities, ranging from 120 A to 180 A, were also used in the experiment. The results demonstrated that higher content of He and N _2 resulted in elevated levels of austenite-forming elements. Therefore, for TIG welding at the arc current intensity of 150 A, it is recommended to utilize the shielding gas mixtures (2.5 vol. % N _2 + 10 vol. % He + 87.5 vol. % Ar). Furthermore, by augmenting the content of both N _2 and He within the Ar shielding gas mixture, in addition to adjusting the arc current, a notable expansion in both the width and depth of the weld profile was achieved. This achievement, in turn, played a pivotal role in securing comprehensive fusion throughout the welding process.

Structural steel components tend to wear when exposed to corrosive and cyclic loading environments. These components can be repaired by welding on failure. This study studied the weld parameters and weld quality (porosity, depth of penetration, and coating thickness), hardness, corrosion, and wear resistance during repair welding. Mild steel samples were weld coated by varying alternating (AC) and direct (DC) currents: 40 A, 50 A, 55 A, 60 A, 65 A, and 70 A. The base material used was AISI 1045 steel, and Castolin 6825 was used as the welding electrode. The results showed that three wear mechanisms were dominant: abrasion, adhesion, and delamination. The porosity in the coated samples increased with increasing currents for both AC and DC. The welding current and current type influenced the coating thickness and penetration depth. When dipped in warm NaCl solution, the corrosion mechanism experienced by both sets of coated samples was pitting corrosion. In both cases (alternating and direct currents), the hardness values increased towards the coating surface from the substrate.

In this study, the feasibility of TIG welding of as-cast Mg–8Li–3Al–2Zn-0.5Y alloys was investigated, and the quality of welded joints using different welding currents was evaluated in terms of microstructural evolution and mechanical properties. The results showed that the welding position of plates was successfully welded with good formability and no obvious welding defects at the investigated processing parameters. Significant refinement of phase size was beneficial to improve the mechanical properties of the welded joints. Under the influence of heat input, the AlLi phase in the heat-affected zone dissolved into the matrix, which improved the mechanical properties of the welded joint. The ultimate tensile strength, yield strength and elongation of the welded joint at 100 A were 224.8 MPa, 177.4 MPa and 9.9%, respectively, which is 159.5%, 159% and 43.8% of the corresponding values of the base alloy in the as-cast state. The burning loss of Li element in the welded joint was effectively controlled, which confirmed the feasibility of this welding process for welding Mg–Li alloys.

Dissimilar welding joints of Inconel 718 (IN718) nickel superalloy with low-carbon AISI 304L austenitic steel (SS304L) were conducted using the Tungsten Inert Gas (TIG) welding process. The present investigation focuses on the effect of different welding currents on the produced dissimilar joints’ microstructure and mechanical properties. The microstructure study was carried out by light optical (LOM) and scanning electron microscopy (SEM), coupled with energy-dispersive spectroscopy (EDS) analysis. The nanoscale investigation was performed via a high-resolution transmission electron microscope (TEM). The mechanical behavior of the TIG joints was investigated via Vickers hardness testing. In all cases, the morphology and the microstructure of the fusion zone (FZ) and the corresponding heat-affected zones (HAZ) of the TIG-welded IN718 and SS304L verified the absence of porosity or other metallurgical defects. Except for carbides and carbonitrides, hard and brittle Laves phases ((FeNiCr)2(NbMoTiSi)) were also identified, which were dispersed in the interdendritic spaces in the form of elongated islands. Prolonged exposure to high temperatures and a slower cooling rate due to higher initial heat input led to the precipitates’ coarsening both in FZ and HAZ and, thus, to the consequent gradual embrittle of the dissimilar joints.

If filler metal AH36 steel is used in bimetallic welding, it has the disadvantage of oxidation in the weld area. Also, the weld crack is encountered if filler metal J4 stainless steel is used in bimetallic welding. In this research, welding methods include the preparation of two types of base metal and a twisted combined filler of AH34 steel and J4 stainless steel as a filler rod applied. The welding of 5 mm thick bimetallic material uses the GTAW (Gas Tungsten Arc Welding) or TIG (Tungsten Inert Gas) process with a current electric welding 60 A, 70 A, and 80 A, one layer and two layers, and angle position 90o to 75o. Preparation of tensile test specimens, provision of shallow notches in the weld where the cross-sectional area of the same as the two-parent metals that have been welded together, tensile testing, and analysis of research data are conducted. The welding results using a current of 60 A with one layer showed a tensile strength of 402 MPa. However, welding with two layers decreased to 200 MPa with a difference of 50 % that means there is a significant difference. In the current of 70 A with one layer, the tensile strength is 433 MPa and with two layers, the value decreases very little at 426 MPa with a difference of 2 %, which means there is a minimal difference and makes the best current selection. For current 80 A with one layer produces tensile strength of 412 MPa. Yet, with two layers, the value decreases slightly to 380 MPa with a difference of 8 %, which means there is a relatively small difference.

The tests discussed in the article aimed to analyse the structure and hardness of the heat affected zone and that of the weld in thin butt joints (1.0 mm) made of Inconel 718 using the TIG method and variable welding linear energy restricted within the range of 45 J/mm to 80 J/mm. The test joints were subjected to visual tests, macro and microscopic metallographic tests, scanning electron microscopy-based structural observations and hardness measurements. The tests concerned with the effect of the TIG welding of butt joints made of 1.0 mm thick sheets (Inconel 718) in laboratory conditions revealed that the most favourable quality of the sheets was obtained when welding arc linear energy was restricted within the range of approximately 45 J/mm to 80 J/mm. An increase in linear energy within the above-presented range led to an increase in the width of the weld and that of the HAZ (observed in the joints subjected to macroscopic metallographic tests). In addition, an increase in linear energy restricted within the aforesaid range increased the grain size in matrix γ (in the HAZ) from approximately 10 μm–20 μm. The structure of the weld contained the zone of columnar grains oriented towards the fusion line as well as large groups of primary grains having the dendritic structure with clearly visible axes of primary dendrites of varied orientation. In addition, the weld structure also contained precipitates in the form of low-melting eutectics located in interdendritic spaces.

In this investigation, the mechanical behaviour and microstructural examination of friction stir processed (FSP) Tungsten Inert Gas (TIG) welded aluminium dissimilar alloys has been studied. The research is proposed to enhance the mechanical characteristics of the aluminium alloy 5052-H32 and aluminium alloy 5083-H111 TIG FSP welded joints. Initially, the TIG welding was done to join aluminium alloy 5052-H32 and aluminium alloy 5083-H111 by employing a ER5356 filler rod. TIG welding is performed by using the following parameters: tungsten electrode diameter (2.4 mm), Current (170 A) and a shielding gas flow rate (argon) (11 l·min-1). Secondarily, the FSP is carried out on TIG welded aluminium alloy 5052-H32 and aluminium alloy 5083-H111 by using different tool rotation speeds (850 to 1050 rpm), tool traverse speeds (24 to 32 mm·min-1) and different number of passes (1 to 3) with a cylindrical pin less tool. The FSP parameters are designed by the Taguchi L9 array to compute the optimized parameters. The tensile strength, microhardness and % of elongation are determined for a total of nine specimens. Finally, the grey relational analysis (GRA) is employed to find out the best FSP parameter out of the set of FSP parameters. The optimal parameters of FSP are a tool rotation speed of 950 rpm, tool traverse speed of 28 mm/min and number of passes of 3. The number of passes are the most influencing factor when compared to other two FSP parameters.

This work emphasizes the investigation that was carried out on SiC powder reinforced Al–Si–Mg ternary alloy TIG weld composite for analyzing, predicting and optimizing the hardness using Taguchi and Response Surface Methodology (RSM). The study focused on optimizing the TIG welding parameters viz, welding current, welding speed, SiC wt.% and gas flow rate for the hardness of composite using RSM. Samples prepared with varying weight percentages of SiC (8,10,12) were subjected to the TIG welding process using ER5356 filler material. A second-order response surface model for hardness is established from experimental data. The predicted as well as measured values are fairly close by, which specifies that the established model can be well utilized to predict the hardness with 95% confidence intervals. Using such a model, one can achieve significant savings in time and cost. The signal to noise ratio of process parameters analysis shows that reinforcement quantity in the composite has the maximum ranking weightage (statistical influence 72.72%) followed by welding current (22.98%), other parameter effect is negligible. The 3D surface plot reveals that maximum hardness lies in the region obtained with the welding current of 210–220 A with 10–12 wt.% SiC and above. From the confirmatory experiments for hardness, it is seen that the experimental and mathematical model results were found fairly with a close agreement.

Partially melted zone (PMZ) is generally the weak region in 2219-T8 aluminum alloy TIG welding joint. In this work, a microstructure-based numerical simulation was performed to analyze the tensile behavior of PMZ. The constitutive behavior and damage mechanism of eutectic structure and Al matrix were determined. Stress–strain distribution and fracture behavior in tensile process were analyzed. Quantitative relationships between eutectic structure and tensile properties of PMZ were proposed. The results showed that the maximum area and clustering of eutectic particles have significant effects on the tensile strength and elongation. Plastic strain mainly concentrated in matrix, and stress concentration occurred in larger eutectic. The tensile cracks initiated from eutectic structure and then propagated into matrix and resulted in the final fracture.

Large residual stress of 2219 aluminum alloy induced by Tungsten Inert Gas (TIG) welding decreases its service performances. Shot peening was adopted to decrease the residual stress of TIG welding. Numerical models of TIG welding and shot peening were established using the combined discrete and finite element methods (DEM–FEM). The results show that TIG welding induces tensile residual stress due to the heat exchange effect and the longitudinal stress is larger than that in the transverse direction. The maximum tensile stress occurs at a depth of 0.1 mm. The surface tensile stress changes to compressive stress after shot peening as the severe deformation induced by the shots changes the stress state of the plate. The maximum value of compressive stress (σm) and the peened depth with compressive stress (Z0) are adopted to describe the peening effect. The absolute value of σm increases with the increased peening speed and nozzle height. Mixed shots with a diameter of 0.8 mm and 1.2 mm induce larger value of σm than those with only a diameter of 1.2 mm. The value of Z0 increases with the ascending shots diameter and nozzle height, while it varies nonmonotonically with the peening speed. The effect of shot peening on the residual stress in TIG welding is discussed.

Activating flux is made up of inorganic material mixed with a volatile medium. The objective of this study is to identify and review the literature in activating flux, and different type of welding techniques. For that purpose, a structured review method is adopted and the Scopus database is used as a primary source for the selection of papers. The papers were identified using the string term of “Activating flux” OR “Activated flux” in the title of papers. And a total of 238 papers were identified for the study. Besides the above few other papers were also reviewed and the materials used, the type of flux used, and the findings of different combinations were highlighted in the form of tables. The findings of the study provide a comprehensive understanding of the different type of welding techniques focusing on TIG welding, and the different combination of flux used and their impact was summarized.

In this research, the effect of current intensity on the corrosion resistance of Ti-6Al-4V alloy welded by Tungsten-inert Gas (TIG) method was investigated. For this purpose, 3 × 50 × 40 mm specimens were prepared and after preparing the surfaces, in a way but joint two-way single pass in vacuum chamber with inert argon with a flow rate of 70, 80 and 90 A were welded. Microstructural studies of base metal (BM), fusion zone (FZ) and heat affected zone (HAZ) were performed using optical microscopy and scanning electron microscopy (SEM). Then, in order to investigate the corrosion resistance of Ti-6Al-4V welded cross sections, the roots of the welded specimens were examined by potentiostatic polarization in seawater and 3.5% NaCl. The results showed that by increasing the welding current intensity from 70 to 80A, the grain size in the weld area as well as the corrosion rate of the weld area in Ti-6Al-4V alloy increased. By varying the flow intensity from 80 to 90A, the corrosion rate and grain size of the weld zone did not change significantly. The corrosion rate of Ti-6Al-4V alloy in 3.5% NaCl solution compared to seawater revealed that the corrosion rate of alloy in 3.5% NaCl solution is higher than its corrosion rate in seawater.

In this work, a new welding method, AC-DC hybrid TIG welding, is used to weld 304 stainless steel. Research on the formation, microstructure, and properties of 304 stainless-steel welded joints are studied by using optical microscope and microhardness. The results show that the weld with AC/DC hybrid welding is a fish-scale pattern, and the density of the fish-scale pattern increases with the increase of AC proportion. Both the weld penetration and the ratio of weld penetration to weld width are the highest when AC accounts for 30%. At this point, the weld penetration is 0.83 mm larger than DC mode, an increase of 93.26%, and the ratio of weld penetration to weld width is 1.6, which is 76.19% higher than DC mode. When the proportion of AC is increased, the microstructure of the weld is equiaxed or columnar, and the microstructure of the heat-affected zone is ferrite in the form of lath. The hardness of the weld is greater than that of the base metal, and the hardness of the heat-affected zone is the lowest. The microhardness distribution of the weld with AC 50% is the most uniform. When AC accounts for 20% and 30%, the average weld hardness is the highest, which are 196.7 HV and 198.1 HV, respectively.

Aluminium alloys are widely used in the fields of electric module packaging, electronic technology, automotive body structure, wind and solar energy management, due to the advantages of high specific strength, high processability, predominantly anti-erosion, increased conductivity, eco-friendly nature and recoverability. The objective of the study is to review the previous papers on aluminium usages, application, and workability parameters. The methodology adopted for the study is to use the structure literature review technique, and the time period selected for the study is 2008–2019 from the Scopus database. The findings of the study concluded that there are various types of aluminium alloys has been used by the previous researchers, and only 6061 is least explored aluminium alloy among all of them. The future scope of the study is to investigate using distinct activating fluxes for raising penetration & to understand consequences on mechanical components & rust behaviour of TIG-welded aluminium metal welds.

TIG welding method is generally used for welding stainless steel and aluminum alloys. It is preferred for the welding of thin sheets due to its low heat input. The fact that the TIG torch does not deviate from the surface to be welded and the arc stability are extremely important factors for welding quality. For this reason, the use of fixtures is an important equipment for TIG welding work. In this study, a multivariable portable and fixed fixture is designed. There are suggestions for fixing the samples to be combined, minimizing the vibration problem and solutions based on heat input. The designed fixture has an adaptable for at least two-axis machines. Sheets of different lengths and widths can be easily welded with this technique without being exposed to distortion. However, copper planch and aluminum cooling fin are used in the method to reduce heat input. Semi-automatically welded 304L austenitic stainless steel sheet materials were compared with manually welded stainless steels and the results were evaluated.

This article presents a fuzzy system-based modeling approach to estimate the weld bead geometry (WBG) from the welding process variables (WPVs) and to achieve a specific weld bead shape. The bacterial memetic algorithm (BMA) is applied to solve these problems in two different roles, as a supervised trainer, and as an optimizer. As a supervised trainer, the BMA is applied to tune two different WBG models. The bead geometry properties (BGP) model follows a traditional approach providing the WBG properties as outputs. The direct profile measurement (DPM) model describes the bead profiles points by a non-linear function realized in the form of fuzzy rules. As an optimizer, the BMA utilizes the developed fuzzy systems to find the solution sets of WPVs to acquire the desired WBG. The best performance is achieved by applying six rules in the BGP model and eleven rules in the DPM model. The results indicate that the normalized root means square error for the validation data set lies in the range of 0.40 - 1.56% for the BGP model and 4.49 - 7.52% for the DPM model. The comparative analysis suggests that the BGP model estimates the BWG in a superior manner when several WPVs are altered. The developed fuzzy systems provide a tool for interpreting the effects of the WPVs. The developed optimizer provides multiple valid set of WPVs to produce the desired WBG, thus supporting the selection of those process variables in applications.

The effect of sensitization on the intergranular corrosion (IGC) of TIG welded AlMg6Mn was investigated by means of scanning electron microscopy (SEM) and corrosion NAMLT tests. The as-received hot rolled AlMg6Mn alloy plates with a thickness of 8 mm were welded by TIG welding with S-AlMg5 as a filler material. Specimens were sensitized at 100°C for 7 days. It was found that welded specimens are sensitive to IGC. The. mass loss in NAML test was 106.7 mg/cm². The welding increases the susceptibility to IGC, since the mass loss of the base metal at the same test was 70.7 mg/cm². The increase of susceptibility to IGC is attributed to significant continually precipitated Mg-rich phase along the grain boundaries during the sensitization treatment.

Automated and intelligent classification of defects can improve productivity, quality, and safety of various welded components used in industries. This study presents a transfer learning approach for accurate classification of tungsten inert gas (TIG) welding defects while joining stainless steel parts. In this approach, eight pre-trained deep learning models (VGG16, VGG19, ResNet50, InceptionV3, InceptionResNetV2, Xception, MobileNetV2, and DenseNet169) were explored to classify welding images into two-class (good weld/bad weld) and multi-class (good weld/burn through/contamination/lack of fusion/lack of shielding gas/high travel speed) classifications. Moreover, four optimizers (SGD, Adam, Adagrad, and Rmsprop) were applied separately to each of the deep learning models to maximize prediction accuracies. All models were evaluated based on testing accuracy, precision, recall, F1 scores, training/validation losses, and accuracies over successive training epochs. Primary results show that the VGG19-SGD and DenseNet169-SGD architectures attained the best testing accuracies for two-class (99.69%) and multi-class (97.28%) defects classifications, respectively. For “burn through,” “contamination,” and “high travel speed” defects, most deep learning models ensured productivity over quality assurance of TIG welded joints. On the other hand, the weld quality was promoted over productivity during classification of “lack of fusion” and “lack of shielding gas” defects. Thus, transfer learning methodology can help boost productivity and quality of welded joints by accurate classification of good and bad welds.

Many applications in industry require a material-to-material joining process of Duplex Stainless Steels (DSS). Therefore, it is essential to investigate the material's properties during a welding process to control the weld quality. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), the chemical composition during the Tungsten Inert Gas (TIG) welding process of DSS could be monitored in situ. The chemical composition could be quantitatively measured using pre-established calibration curves. Although the surface temperature and the welding plasma have a high influence on the spectral intensities, reliable composition measurements were possible. The concentration of alloying elements could be mapped during the TIG welding process.

Wire Cut EDM technique is widely used to make small and precision cuts. Generally, a material with fragile geometry and hard structure is cut using a wire cut EDM. The main advantage of this method is that, it is a non-conventional machining process therefore it does not have a contact between the tool (wire) and the workpiece. This advantage gives it an edge over other machining techniques and it makes the process capable of machining even the weak structured and delicate materials. In the present experimental work, by using various machining parameters (Pulse on Time, Pulse off Time, and Wire Speed) were optimized using Taguchi’s L9 orthogonal array. Welding is most the important industrial processes, therefore lots of techniques have been developed to get an efficient and low-cost welding process for different types of materials. In this we will discuss about the welding characteristics of the of tig welding joints produced using different currents. That is, by changing the voltages for the number of passes to improve and strengthen the welded joint The research work aims to optimize the wire cut EDM process parameters for AISI 308 steel and analyze the welding characteristics of Tungsten Inert Gas (TIG) welded joints of the same material. The study intends to find the optimum combination of process parameters that would lead to the highest material removal rate, lowest wear rate, and best tensile properties of the material.

7075 aluminum alloy butt welding was carried out by TIG welding with self-made 7075 wire. The effects of different currents on the microstructure and mechanical properties of the joint before and after heat treatment were studied. Before heat treatment, the strength and elongation of the joint are 274.84 MPa and 6.3%, which are determined by the presence of a large number of second phase precipitates with different shapes. After heat treatment, the tensile strength and elongation are increased to 511.75 MPa and 13.76%. Since most of the second phase has been dissolved, the grain size becomes the decisive factor. The fine grain size and more sufficient recrystallization degree make the mechanical properties of the low-current joint better.

Welding processes are widely used in many industries. The determination of welding parameters and the study of their influence on the mechanical and metallurgical behavior of materials require multiple experiments, and the relevant studies are costly in terms of time and resources. Thus, numerical simulations can serve as a solution when it comes to choosing the appropriate welding process and optimizing its parameters while minimizing costs. The present work contributes to the development of a finite element code, using MATLAB software, for the prediction of thermo-mechanical and metallurgical behavior during the Tungsten inert gas (TIG) welding process. Numerical computation is based on the mathematical formulation of physical phenomena and thermal exchanges. In this paper, results dealing with the prediction of the temperature field evolution during the C50 steel TIG-welding process are presented. In this case, the thermal problem is solved numerically using the finite element method. The memory and computation time problems are solved using optimal stocking and resolution algorithms. To validate the developed computation code, numerical results are first compared with other published numerical results, then with our experimental data. A satisfactory concordance between simulated temperature evolutions and those measured with thermocouples implanted in the welded sheets was found.

Titanium and titanium alloys can be welded by gas tungsten arc, gas metal arc, plasma arc and electron beam welding processes. Titanium material is a reactive metal and is sensitive to embrittlement by oxygen, nitrogen, and hydrogen gas at elevated temperatures. Consequently, the metal must be protected from atmospheric contamination. This can be provided by shielding the metal with welding grade inert gas. The present work describes the application of TIG arc welding to titanium and investigated the effect of welding parameters like weld current, weld gap and gas flow rate on mechanical properties of welded joints of unalloyed commercially pure titanium Gr-2 materials. Taguchi optimization method has been used to find out optimal setting of parameters for weld joints characterization. The welded joints showed maximum ultimate tensile strength of about 429MPa with percentage elongation of 23.33%. A significant grain coarsening has noticed in the fusion zone consisting of a-phase in different direction bounded by -phase. The hardness value at fusion zone and base metal are typically observed to be 235HV and 145HV respectively.

Automated in-process Non-Destructive Testing (NDT) systems are rapidly gaining traction within the manufacturing industry as they reduce manufacturing time and costs. When considering calibration and verification of such systems, creating defects of known geometry and nature during the deposition of a weld can: (I) help examine the capability of the automated system to detect and characterise defects, (II) be used to form a database of signals associated with different defect types to train intelligent defect classification algorithms, and (III) act as a basis for in-process gain calibration during weld inspection at high temperatures, where the ultrasound beam can be skewed as a result of velocity gradients. In view of this, this paper investigates two unique methodologies for introducing: (a) lack of fusion weld defects by embedding tungsten in the weld and (b) creating artificial weld cracks by quenching to imitate the real cracking scenarios. According to the results of Phased Array Ultrasound Testing (PAUT) inspections, the methodologies used for embedding the artificial defects were successful. The validity of inspections was also verified by extracting micrographs from the defective sections of the welds, and model-based simulations were carried out to gain a better understanding of the wave propagation path and interaction with the generated defects.

This paper investigated the design of a system to monitor the status of the robotic welding process of thin-walled components for an aircraft jet engine. Opportunities to measure and log processing parameters, such as welding speed, current, and voltage, on the existing production cell were taken. The acquired data were processed using elements of descriptive statistics. Obtained indicators were matched with physical inspection results of the weld’s quality. The adopted methodology was used to identify an essential parameter determining the presence of defined weld defects. The developed solution was implemented in the production cell.

Industrial applications often require welded joints of dissimilar metals to perform reliably under adverse working conditions. Such conditions demand high resistance to failure modes, such as fatigue, corrosion, and creep. In applications involving intense vibrational and cyclic loading conditions, high strength-to-weight ratio metals, including aluminum, are more vulnerable to fatigue failure. This study investigates the fatigue strength of base metals and tungsten inert gas welded joints of the two most widely used aluminum alloys, AA7075 and AA2024, under four-point rotating bending. For the comparative study, these dissimilar alloys were joined together by using two different filler rods, AA4047 and AA4043, under similar welding conditions. SN curves for all the samples were generated through the experimental iterations. A comparison of different results shows that welded samples have better fatigue strength than the base metals, while, as a filler, AA4047 has better resistance to fatigue fracture than AA4043.

The current research studies the corrosion behavior of Low Carbon Steel 1020 AISI welded joint by means of TIG welding method using mutable DC current and constant voltage. Before the welding process, shot peening by steel balls for certain welded joints is applied to the sheet metal, and then welding under the same welding conditions without shot peening. A number of corrosion inspection samples have been prepared with the measurements of (15 * 15 * 3 mm), according to ASTM (G71-31). Microstructure, residual stress has been tested and the corrosion test has been conducted electrochemically in 3.5 per cent NaCl solution for all samples. Corrosion rate was computed by means of the Tafel equation. The results show a rise in corrosion rate in some welded joints compared with other welded joints and base metal due to the variation in heat input from the input current for each weld passes. Shot peening process contributed to lower corrosion rate compared to welded joints without shot peening, due to the residual compression stresses produced by shot peening process. The best results obtained when number of welds passes and welding current are decreased to get suitable heat input.

In this research work, Inconel 718 specimens are fabricated by Direct Metal Laser Sintering process in the closed chamber which is filled with argon gas environment from a pre-alloyed powder. The process contains the high intensity of the laser source to melt the powder material, and the segment is placed on the top of the previous layer. Plates were vertically fabricated systematically (i.e., z-axis) and columnar grains are exhibited perpendicular to the build direction (i.e., x-axis). Test specimens are stress-relieved at 980°C for 2 hours and the recrystallized zone are found to be spheroid structure precipitates. The Ni-Cr matrix in the recrystallized interface and grain boundaries is observed in the samples, the micro hardness of the as-fabricated material is found as 340-350 VHN. Also, correspondingly mechanical properties are comparable with the wrought inco-718 alloy material. Further, the as build condition specimens are used for making butt joint configuration using Tungsten Inert Gas (TIG) welding process and Mechanical and microstructural properties are studied. The studies on welding of additive manufactured component will ensure the weldability of the AM material for the research community and industry.

Weld quality mainly depends on the weld bead geometry and mechanical-metallurgical characteristics of the welded joint which has a direct relationship with the type of welding process being used and its input process parameters i.e. welding current, arc voltage, travel speed etc. In the present study, determination of tungsten inert gas (TIG) welding input parameters for achieving maximum tensile strength of 316L austenitic stainless steel is investigated. Box-Behnken design of response surface methodology has been employed to formulate the experimental plan to identify the effect of process parameters on tensile strength. Square butt joint configuration has been made using three factors - three levels of welding input parameters. Joint strength has been evaluated by notch tensile strength (NTS) and Unnotch tensile strength (UTS) method and correlated with microstructure and micro hardness of the weld. The results indicate that gas flow rate has greater influence on both NTS and UTS followed by welding current.

Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g., highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research to date. For that reason, in this work, the weldability depending on the surface preparation of a CoCrFeMnNi HEA and a CoCrNi MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. However, based on the results, the crack mechanism cannot be conclusively identified as either a liquid metal embrittlement (LME) or hot cracking-like liquid film separation.

For a low cost, there are industrial infrared monitoring systems used for imperfection detection and identification in welded joints. The key drawback that impedes real life industrial applications is the low spatial resolution, as well as the temporal resolution of low-cost infrared (IR) cameras. This is also the case in tungsten inert gas (TIG) welding. Taking into consideration the influence of voltage on the arc energy and heat input, high frequency sampled voltage was used to evaluate the interpolated temporal resolution of IR sequences. Additionally, a reflected temperature correction method was proposed to reduce the uncertainty of absolute temperature measurement with a thermographic camera. The proposed method was applied to detect several imperfection types, such as lack of or incomplete penetration as well as incorrect weld shape and size (including burnouts). Results obtained for different interpolation factors were compared. The obtained results emphasize the validity of reflected temperature correction method. For the weld defects detection task, the smallest detectable defect was found for various interpolation factors. Moreover, the correspondence of arc voltage and the joint temperature was checked. Additionally, a set of decision rules was elaborated on and applied to distinguish between various joint conditions. It was found that defects that do not have symmetrical temperature distribution with respect to the joint axis are harder to identify.

The present work develops a multi-region dynamic coupling model for fluid flow, heat transfer and arc–melt interaction in tungsten inert gas (TIG) welding using the dynamic mesh technique. The arc–weld pool unified model is developed on basis of magnetohydrodynamic (MHD) equations and the interface is tracked using the dynamic mesh method. The numerical model for arc is firstly validated by comparing the calculated temperature profiles and essential results with the former experimental data. For weld pool convection solution, the drag, Marangoni, buoyancy and electromagnetic forces are separately validated, and then taken into account. Moreover, the model considering interface deformation is adopted in a stationary TIG welding process with SUS304 stainless steel and the effect of interface deformation is investigated. The depression of weld pool center and the lifting of pool periphery are both predicted. The results show that the weld pool shape calculated with considering the interface deformation is more accurate.

Titanium and Titanium Alloys can be welded by gas tungsten arc, gas metal arc, plasma arc and electron beam welding processes. Titanium material is a reactive metal and is sensitive to embrittlement by oxygen, nitrogen, and hydrogen gas, at elevated temperatures. Consequently, the metal must be protected from atmospheric contamination. This can be provided by shielding the metal with welding grade inert gas. The present work describes the application of TIG arc welding to titanium and investigated the effect of welding parameters like weld current, weld gap and gas flow rate on mechanical properties of welded joints of unalloyed commercially pure titanium Gr-2 materials. Taguchi optimization method has been used to find out optimal setting of parameters for weld joints characterization. The welded joints showed an ultimate tensile strength of about 429 MPa with 23.33% elongation. A significant grain coarsening is noticed in the fusion zone consisting of α-phase in different direction bounded by β-phase. The hardness value at fusion zone and base metal are typically observed to be 235 and 145HV.