TIG Welding Method Research Articles

Philosophy analysis of AISI 316/AISI 410 stainless steel joint by means of mechanical and metallurgical properties using TIG welding method

Philosophy analysis of AISI 316/AISI 410 stainless steel joint by means of mechanical and metallurgical properties using TIG welding method

Effect of reducing heat input on autogenous TIG welding of Ti–6Al–4V alloy

3 mm-thick Ti–6Al–4V alloy plates were welded in butt joint configuration through autogenous TIG welding method using a trailing gas shielding arrangement. After attaining full penetrated weld joint with appropriate heat input, subsequent experiments were conducted by reducing the heat input, which was obtained through combination of higher welding current and scan speed. An in-depth microstructural analysis of the weld joint executed under different heat input conditions shows a strong correlation with the microhardness, tensile strength, and flexural strength of the weld joint. A significant improvement in the mechanical properties of the weld joint was perceived for employing lower heat input. Alteration in the primary-α, primary-β, and martensite-α phases, due to the variation in heat input, amended the mechanical properties of the weld joint under lower heat input condition. With the reduction of heat input from 0.406 to 0.232 kJ/mm, the tensile and flexural strengths of the weld joint increased from 1020 to 1070 MPa, and from 1015 to 1950 MPa, respectively. The tensile strength of the joint reached up to 98% of the base material at minimum heat input (0.232 kJ/mm). The experimental results show the potential of TIG welding for joining Ti–6Al–4V alloy under low heat input condition.

Investigation of combining the 304L and S355J2C+N materials with TIG welding in terms of microstructure and mechanical properties

This study reports the investigation of the joining of S355J2C+N and 304L steels by the TIG welding method in terms of microstructure and mechanical properties. The effects of the microstructure of the heat-affected zones, the weld zone formed by the combination of two base metals with different superior properties, on the mechanical properties were investigated. In the optical examination, optical microscope (OM), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD) analyses were applied. Mechanical tests were carried out using tests such as microhardness (HV 0.1), bending, Charpy V-Notch impact, and tensile test. A microstructure was detected in the welded joint, which affects the mechanical properties. Grain size distribution in area fraction was determined from the EBSD maps of S355J2C+N steel, welded zone, heat affected zone (HAZ), and 304L. Average grain size of S355J2C+N base metal was 5.35 ± 1 μm, mean grain size of 304L base metal was 35 ± 5 μm, mean grain size for 304L HAZ was 41 ± 6 μm, and for S355J2C+N HAZ 5.47 ± 1 μm. Vickers microhardness values were measured as 222 ± 10 H V for 304 L base metal and 187 ± 10 HV for S355J2C+N base metal. The hardness of the weld center has the highest hardness and was determined as 302 ± 10 HV. In the tensile test, the highest tensile strength observed in the specimens extracted from the transverse direction is 534.88 ± 10 MPa. In the tensile test, a rupture occurred in S355J2C+N metal. In the bending test, the bending forces of 304L and S355J2C+N base metals were measured as 27.175 ± 4 kN and 28.480 ± 2 kN, respectively. The bending force of the transverse welded samples was 28.245 ± 2 kN, while the bending force of the longitudinal welded samples was 31.380 ± 2 kN. Weld efficiency was obtained as 106%. Tungsten inert arc welding provided good properties such as strength, sealing, and toughness in the combination of stainless and carbon steel, and this welding method was determined to be suitable for the successful joining of these two dissimilar metals.

Effect of the Welding Filler Material on the Mechanical and Corrosive Behavior of Böhler W350 ISOBLOC Hot Forming Tool Steel

In this study, the effects of different welding filler materials were examined in the case of repair welding of pressure infiltration casting tool made out of Böhler W350 ISOBLOC hot forming tool steel. Three additional welding filler materials were used: Böhler W350 ISOBLOC (same as the raw material), Böhler W300 ISOBLOC and Anviloy® 1150 tungsten alloy. The welds were created with TIG welding method. The used welding filler material has an impact on the mechanical and corrosive properties of the tool. The hardness of the weld was measured to determine its resistance against mechanical stress. The corrosion rate was measured because molten aluminium corrodes workpieces due to its high chemical activity. It was concluded that a single-pass weld corrosion speed is 0.142 ± 0.010 mm/year while a weld containing multiple layers and passes has the corrosion speed of 0.069 ± 0.005 mm/year which is approximately 48% of the corrosion speed of the single-pass weld. Furthermore, the hardness of a weld made with W350 welding filler material significantly drops in the upper layers of the weld, down to 273 HV1 while the hardness of the base material is 495 ± 8 HV1. The results show that the multiple layers and passes welds have better corrosion resistance and less hardness than the single-pass weld.

Interface microstructure and mechanical properties of copper/304 stainless steel dissimilar joint assisted by Ni transition layer using ultrasonic additive manufacturing (UAM)

The copper/304 stainless steel joints with high strength are obtained by preparing nickel transition layer on the steel surface using ultrasonic additive manufacturing (UAM) and pulsed TIG welding method. The results show that the addition of the nickel intermediate layer achieves metallurgical isolation between copper and steel, inhibits the infiltration of copper into steel grain boundaries and reduces joint stress, resulting in the formation of hybrid joints including fusion brazing (copper-nickel) and diffusion welding (nickel-steel). The weld and the vicinity of the interface are mainly composed of Cu-Ni solid solution and Ni-rich phase. The wavy texture produced by UAM on the nickel surface can form mechanical interlock at the interface to improve the joint strength, and finally all joints fracture near the fusion line on the copper side.

Appropriate amount of TiB2 particles causes the ductile fracture of the un-weldable spray-formed 7055 aluminium alloy TIG-welded joint

Spray-formed 7055 aluminium alloy is often referred to as an un-weldable aluminium alloy because of the low strength and high brittleness of the fusion welding joints prepared using the traditional welding wires. In this study, new welding wires with different content of TiB2 particles were developed, and the spray-formed 7055 aluminium alloy was welded using these wires in conjunction with the use of the TIG welding method. The microstructure and tensile properties of the TIG-welded joints were investigated. The results show that TiB2-7055 welded joints gradually change from coarse grain to fine equiaxial grain as a function of the content of TiB2 particles, and their tensile strengths and elongations first increase and then decrease. The tensile strength and elongation of 0 wt.% TiB2-7055, 0.5 wt.% TiB2-7055, 1.5 wt.% TiB2-7055 and 3.0 wt.% TiB2-7055 welds are 245 MPa and 1.5%, 270 MPa and 2.0%, 310 MPa and 5.4%, and 285 MPa and 2.4%, respectively. The tensile strength and elongation of the 1.5 wt.% TiB2-7055 weld were the highest, showing ductile fracture. The developments of new welding wires which consist of TiB2 particles promote additional applications of the spray-formed 7055 aluminium alloy.

A Study of the Influence of Local Heat Treatment on the Structure of Welded Titanium Pipelines

The article analyzes the results of a study of the influence of zonal heat treatment on the structure of welded joints of pipeline elements made of titanium alloys Ti-3.5Al-1.5Mn. In the manufacture of such structures, the TIG welding method is used to join pipe elements, after which the heat treatment method can be used to relieve residual stresses. The experiments have confirmed the effectiveness of zonal heat treatment preceded by welding. It was revealed that for welded joints made of titanium alloys, heat treatment can stabilize the structure. In experiments conducted by the method of optical metallography, the structure of heat treated and untreated welded joints was investigated. The influence of heat treatment on the weld structure and heat-affected zone was identified.

Influence of austenitic interlayer on the properties of stellite sur- facing welds after impact-hardening

Stellites (Co-Cr-W-C) are the specific group of coating materials used for surface modification of the engineering materials and for remanufacturing too. The aim of the paper was to research the influence of austenitic (308LSi) interlayer present on hardening level of stellite 1 and 6 after impact treatment. The samples have been cladded by TIG welding method with interlayer and without. Before impact hardening the samples have been visually and penetrant non-destructive tested. The samples after impact hardening have been tested by metallographic and Vickers hardness methods. The highest impact hardening effect have been revealed for coatings deposited with interlayer. The highest impact hardening effect was achieved for the padding welds produced with the interlayer, i.e. for stellite 1 (increased by 29.8%) and stellite 6 (increased by 42.7%). The hardening of the coating samples deposited without interlayer was lower and amounted to stellite 1 (increased by 13.7%) and stellite 6 (increased by 29.8%) respectively. The highest hardness values were obtained for impact-hardened cladded welds without the use of an interlayer (stellite 1; 790 HV0.1 and stellite 6; 732 HV0.1). The use of an interlayer reduces the hardness of the stellite coating while increasing the susceptibility to hardening and plastic deformation of the produced coating.

Weldability Investigation and Optimization of Process Variables for TIG‐Welded Aluminium Alloy (AA 8006)

Aluminium and its alloys play a significant role in engineering material applications due to its low weight ratio and superior corrosion resistance. The welding of aluminium alloy is challenging for the normal conventional arc welding processes. This research tries to resolve those issues by the Tungsten Inert Gas welding process. The TIG welding method is an easy, friendly process to perform welding. The widely applicable wrought aluminium AA8006 alloy, which was not considered for TIG welding in earlier studies, is considered in this investigation. For optimizing the number of experiments, the Taguchi experimental design of L9 orthogonal array type experimental design/plan was employed by considering major influencing process parameters like welding speed, base current, and peak current at three levels. The welded samples are included to investigate mechanical characterizations like surface hardness and strengths for standing tensile and impact loading. The results of the investigation on mechanical characterization of permanent joint of aluminium AA8006 alloy TIG welding were statistically analyzed and discussed. The 3D profilometric images of tensile‐tested specimens were investigated, and they suggested optimized process parameters based on the result investigations.

Electrochemical studies and corrosion resistance of activated Tungsten inert gas AISI SS316L weldments

Welding is the most convenient fabrication process with tremendous development in past few decades. The noteworthy technique is Activated flux TIG welding method (also known as A-TIG welding) that was well-equipped a little while back, which enhances productivity and quality of weld joints by better depth of penetration. In this research work, the electrochemical studies are performed to investigate the corrosion resistance of excellent depth of penetration A-TIG welded 316L stainless steel (SS316L) sample at room temperature. At dilute aqueous ambience, Potentiodynamic studies reveal that the SS316L welding joints have an apathetic attitude with certain range. Electrochemical Impedance calculations illustrate the breakdown occurs due to corrosion in alkaline circumstances.

Corrosion Behavior Evaluation of TIG Welding Joint of Low Carbon Steel

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.

Experimental investigation on the effect of welding parameters of TIG welded joints using ANOVA

Abstract To improve the mechanical properties of the weld structure and to reduce the manufacturing costs, the welding parameters of TIG welding process needs to be optimized. The present investigation focused on the optimization of the procedure parameters of TIG joining procedure. AISI 304 materials selected as a base metal. The dimension of specimen is 200 mm × 50 mm × 3 mm. The specimen was butt-welded by the TIG welding method. Selection of input parameters is based on their significance effect on the mechanical properties of weld structure. The selected input parameters are Voltage, Current, Gas flow and root gap. The number of experiments carried out is 27, which is designed by Taguchi L27 orthogonal array using four factors and 3 levels by MINITAB-17software. Conducting tensile strength test checks the final weld quality

Experimental and numerical investigation of fixture time on distortion of welded part

In this paper, the effect of clamping time on welding distortion is studied. The welding process has been done in austenitic stainless steel 304L butt-welded joint by TIG welding method. The numerical thermo-mechanical analysis is performed using commercial finite element software ABAQUS. The welding simulation is performed using the birth and death of elements technique. The heat source model that used in this study is the Goldak double-ellipsoidal model. At last, for verifying numerical results, a set of experimental tests have been carried out and welding distortion has been measured. The experimental measured data are compared with numerical (FEM) results. The results showed that the clamping causes change in direction of bending and angular distortions (opposite of without clamping mode). Any increase in clamping time relatively causes a decrease in angular and bending distortions. A 70% reduction of angular and bending distortions were observed in cold release mode (unclamping after the workpiece has cooled down to room temperature) compared with hot release mode (an immediate unclamping after welding). The position of clamping has a significant effect on distortion reduction as well. If clamping position is moved closer to the weld line, the distortion is decreased. By reducing relative clamping distance of 60 to 20 mm, the angular distortion is reduced to 0.15 mm which is about 25% and bending distortion of 0.6 mm (40%) can be achieved. The angular and bending distortions are increased when the sheet width is reduced during the experiments. It should be noted that the measured results of experiments and numerical method are in a relatively good agreement and the amount of error is within the acceptable limits.

The Influence of Corrosion on the Mechanical Behavior of AISI 316L Stainless Steel Welds

Stainless steels are widely used because they have high corrosion resistance. However, they can also suffer corrosion due to the constant aggressive effect of the environment or due to chemical and physical malfunctions. It is of great importance to determine the behavior of welded austenitic stainless steels in corrosive environments for safer construction. For this reason, in this study, the corrosion and mechanical behavior of welded austenitic stainless steels exposed to salt spray was investigated. In the first stage, commercially available AISI 316L austenitic stainless steel materials with 4 mm thicknesswere joined with the TIG welding method,both with and without filler metal. To specify the structure of the weld zone, the micro-macrostructure and microhardness values of the welded samples were examined before the salt spray experiments. The salt spray test was performed in compliance with the EN ISO 9227 Corrosion test in artificial environmentsstandard, in which the tensile samples of welded AISI 316L materials were subjected to salt spray testup to 1000 hours.Tensile tests were carried out following salt spray tests. DOI: http://dx.doi.org/10.5755/j01.mech.25.2.21551

Gas Pool Coupled Activating TIG Welding Method with Coupling Arc Electrode

Gas pool coupled activating TIG (GPCA-TIG) welding put forward in-house can dramatically enhance weld penetration of TIG welding through introducing active element oxygen to reverse the Marangoni convection flow in the molten pool. In order to further improve the welding productivity, the normal solid tungsten electrode is replaced by a kind of coupling arc electrode. The changes of arc pressure distribution along anode surface and the weld appearance were evaluated. On this basis, the dependences of weld shape characterized with weld depth, width and undercut on the main welding parameters were discussed. The results indicate, the substitution of coupling arc electrode can lead to an obvious decrease of arc pressure. Compared to hollow tungsten electrode and twin tungsten electrodes, the coupling arc electrode is much easier to manufacture and has more compacter structure. Combined with the symmetric distribution of arc pressure in different directions, this electrode has extensive adaptability. In the GPCA-TIG welding with coupling arc electrode, both the substitution of coupling arc electrode and the introduction of outer active gas oxygen can reduce the possibilities of producing humping bead and undercut. Their joint action makes this welding method have the capability of realizing high travel speed and deep penetration welding.

Managing the influence of microstructure defects on the strength of EN AW 5754 aluminium alloy welded joints executed with the TIG method

The paper concerns the issue of the impact of welding defects on the strength of EN AW 5754 aluminium alloy welded joints, executed with the TIG welding method (tungsten inert gas, i.e., a method of welding with a non-consumable tungsten electrode shielded with inert gases). The article presents examples of operating damage to welded joints and discusses the factors impacting the weld quality. The strength test results of welding samples taken under different process parameters were presented. The impact of welding defects and non-conformities identified with a CAT test on the weld joint impact was analysed. The studies showed a strong relation between the presence of welding defects, welding process parameters and weld strength.

Effect of Alternate Supply of Shielding Gases of Tungsten Inert Gas Welding on Mechanical Properties of Austenitic Stainless Steel

In the present study, an attempt is made to study the effect of alternate supply of the shielding gas in comparison with the conventional method of TIG welding with pure argon gas. The two sets of combination are used as 10–10 and 40–20 s for alternate supply of the Argon and Helium shielding gas respectively. The effect of alternate supply of shielding gas is studied on the mechanical properties like bend test, tensile test and impact test. The full factorial experimental design is applied for three set of combinations. The ANOVA is used to find significant parameters for the process and regression analysis used to develop the mathematical model. The result shows that the alternate supply of the shielding gas for 10–10 s provides better result for the bend, tensile and impact test as compared with the conventional argon gas and the alternate supply of 40–20 s argon and helium gas respectively. Welding speed can be increased for alternate supply of the shielding gas that can reduce the total welding cost.

Effect of Active Gas on Weld Shape and Microstructure of Highly Efficient TIG Welded A516 Low Carbon Steel

A highly efficient TIG welding method was performed to increase the weld penetration and compared with the conventional TIG welding process. A double-shielded gas flow system was designed to apply Ar + CO2 mixed gas as the outer layer, while the inner layer remained pure argon to impede oxidation of the electrode. The results demonstrate that the addition of the active gas to the molten pool controls the Marangoni convection on the liquid pool surface so that the weld shape changes from a shallow shape to a deep and narrow weld pool owing to the change in direction of Marangoni convection. The increase in CO2 content from 0.5 to 2 % leads to the reduction in the weld depth which is due to the formation of a thick oxide layer on the weld pool surface and reduction in the interface between the shielding gas and the weld pool. Moreover, Preheating of the samples causes the formation of deeper fusion zone profiles which can be attributed to the slow cooling rate and the increase of heat concentration in the weld pool.

비접촉 SH-EMAT을 이용한 TIG용접부 건전성 평가

An EMAT can be used to reliably detect defects as it serves as a non-contact transducer with the ability to transmit ultrasonic waves into specimens without couplant. Moreover, an EMAT can easily generate desired waves by altering the design of the coil and magnet. This study proposes an SH-EMAT to evaluate the integrity of the TIG welding part. A stainless steel was welded using the TIG welding method. The welding current was varied to create artificial defects. Both the PA-UT and the RT were applied to verify the defect size. The experimental results generated by using the EMAT were compared with those methods. The amplitude was observed to decrease with an increase in the defect size. These results confirmed that the presence of defects can be reliably detected by attenuation of signal amplitude. The results demonstrated that the proposed method is suitable for evaluating the integrity of TIG welding.

Comparison of microstructure and mechanical properties of TIG and laser welding joints of a new Al–Zn–Mg–Cu alloy

Sheets of a new Al–Zn–Mg–Cu alloy with T6 temper were welded using TIG and laser welding method. Microstructure characteristics and mechanical properties of joints were contrastively analyzed. Results show that the width of the fusion zone (FZ) and heat affected zone (HAZ) in laser joint is obviously smaller. The FZs in TIG and laser joints are both made up of dendritic equiaxed grains and lots of coarse particles, the mean grain size is 33.9μm and 6.1μm respectively, and the coarse particles are identified as the T (AlZnMgCu) phase. The two factors of grain size and alloying elements distribution are combined to result in almost the same microhardness of the two FZs. Moreover, the grain morphology, grain size and degree of recrystallization of the two HAZs are almost the same with base metal (BM). Due to the higher heating and cooling rate of welding thermal cycles in HAZ of laser joint, the microhardness is obviously higher. The minimum microhardness of the two joints is obtained in FZ where the fractures always occur in the tensile tests, the ultimate tensile strength of TIG and laser joints is 436.2MPa and 471.1MPa, the elongation of them is about 7.5% and 5.1% respectively.