Effect Of Welding Parameters Research Articles

Study on weld formation and its mechanism in laser-TIG hybrid welding with filler wire of a titanium alloy

A series of laser-tungsten inert gas hybrid welding with filler wire experiments were performed on the TA15 titanium alloys to investigate the effect of welding parameters, such as the distance between the axis of the laser beam and the tip of the tungsten electrode (Dla), the defocused distance of the laser beam, and its CO2 concentration in the shielding gas, on the weld appearance and dimension. The mechanism of the weld formation was then analyzed. The results demonstrated that by adjusting space position between the heat sources and protecting the shielding gas content, the undercut defect could be suppressed effectively in the hybrid welding process. With the increase in the Dla, defocused distance, and CO2 concentration, the width of the top weld presented an increasing trend, while the width and reinforcement of the backside showed a decreasing trend. The ridgelike appearance may be effectively suppressed if the Dla, defocused distance of the laser beam, and CO2 concentration in the argon shielding gas were more than 2 mm, 4 mm, and 2%, respectively, because the Dla, defocused distance, and CO2-determined energy concentration, surface tension, and Marangoni convection determine the molten metal flow direction.

Microstructural features and corrosion analysis of A517 steel joint processed by friction stir welding

Microstructural observations of friction stir welds of A517(B) steel showed that within the range of welding variables, martensite phase was hindered. Stir zone microstructure displayed coarse-grained upper bainite associated with granular bainite. HAZ consisted of decomposed bainite morphology of lath-like and equiaxed. Electron backscatter diffraction analysis showed a random oriented recrystallized grain. The corrosion behavior in 3.5 wt% NaCl solution revealed negatively shift of corrosion potential with increasing of traverse speed. However, the effect of welding parameters on cathodic behavior was more predominant than that on anodic behavior; associated with the microstructural alterations. Pitting of corrosion rust layer was identified as the main mechanism of corrosion attack in base material and welds. Although, corrosion current density of weld in all of the applied welding condition was slightly lower than that in the base material, however, this study provides recommendation for application of A517 steel jointed by friction stir welding in marine environment.

Study of the welding parameters effect on the tunnel void area during friction stir welding of 1060 aluminum alloy

Friction stir welding is a relatively novel solid state method which produces ultra fine-grained microstructure and promoted mechanical properties due to the severe plastic deformation induced during welding. These features, of course, would be obtained if the welding parameters have been justified so that the welding zone becomes free of any defect specially tunnel cavity. This defect was primarily caused by an insufficient heat input during welding. In this study, a mathematical model has been presented to estimate the heat input generation during welding pertaining to the frictional work dissipated between the tool/workpiece interface, and moreover, the heat produced by the mechanical stirring of the plastically deformed material around the pin. The aim was to correlate the heat input generation and the tunnel void area. Aluminum plates with commercial purity were used for experimental efforts. During friction stir welding, a thermal camera was utilized to measure the maximum temperature of the material. After welding, samples cut through the transverse direction and examined for the area of tunnel cavity, and the extent of thermo-mechanically affected zone, as well. Comparison among the tunnel cavity areas with the heat input generations showed that to eliminate the tunnel cavity, at least a minimum heat input of about 800 J mm−1 was required.

Effect of Friction Stir Welding and Friction Stir Processing Parameters on The Efficiency of Joints

Friction Stir Welding is one of the most practical welding process at the solid state. Friction Stir Processing is used to enhance the microstructure of FSW welded zone. The present study investigates the effect of welding parameters on the tensile properties of FSW and FSP joining 3 mm AA 5083 - H111 aluminum alloy by means of stress – strain curve with a uniaxial tensile test and by comparing the efficiency between FSW , FSP and base metal .The experiments were conducted with 1000,1500 and 2000 rpm rotation speeds ,and 20,40 and 60 mm/min travel speed. The best result of the welding joint was shown at the 20 mm/min feed speed and 1500 rpm rotational speed for FSW, and 40 mm/min feed speed and 1500 rpm rotation speed for FSP. The efficiency of ultimate tensile strength reaches to 92% for FSW and 94% for FSP.

Properties and optimization of friction stir spot welded aluminum alloy 3003-H14

Abstract The lightweighting potential in modern manufacturing has been enhanced via the emergence of novel friction stir spot welding approaches by eliminating the conventional joining challenges of aluminum alloys. Optimizing the tool profile of friction stir spot welded joints is thus essential due to the direct controlling influence of tool morphology on material flow, bonding and weld quality. Therefore, this study examines the optimization of friction stir spot welded 1 mm thick 3003-H14 wrought aluminum alloy, by using a cylindrically threaded pin tool morphology and the Taguchi optimization methodology. Tool rotational speed, plunge depth and dwell time are utilized as welding parameters, while maximum shear failure load is employed as the response in this study. Analysis of variance (ANOVA) is employed to systematically investigate the main effect and interaction effect of welding parameters on weld performance. A maximum shear failure load of 2530 N was attained at a parameter combination of 1.50...

Effects of Welding Parameters on Mechanical Properties in Electron Beam Welded CuCrZr Alloy Plates

CuCrZr alloys are attractive structural materials for plasma-facing components (PFC) and heat sink element in the International Thermonuclear Experimental Reactor (ITER) fusion reactors. This material has gained so much attention because of its high thermal conductivity and fracture toughness, high resistance to radiation damage and stability at elevated temperatures. The objective of this work is to study the effects of electron beam welding parameters on the mechanical strength of the butt welded CuCrZr joint. Taguchi method is used as the design of experiments to optimize the input parameters, such as accelerating voltage, beam current, welding speed, oscillation amplitude and frequency. The joint strength and ductility are the desired responses, which are measured through ultimate tensile strength and percent elongation, respectively. Accelerating voltage and welding speed are found to have significant influence on the strength. A combination of low amplitude and high-frequency oscillation is suggested for the higher joint strength and ductility. There is a close agreement between Taguchi predicted results and experimental ones. Fractographic analysis of joint and weld zone analysis are carried out to study the failure behaviour and microstructural variation in the weld zone, respectively.

Multi-axis force measurements of polymer friction stir welding

In this study, high-molecular-weight-polyethylene sheets were welded in the butt-joint configuration in order to investigate the effect of welding parameters on the generated forces during welding. The welding procedure was performed using newly developed clamping device with the ability to measure and acquire the forces during welding in X, Y and Z directions (FX, FY and FZ). Using a welding tool with a stationary shoulder and position control, the applied force is kept approximately constant during the entire welding extension. The obtained results enabled the identification of the influence of each individual welding parameter on the applied forces. The axial force is the most influential force during this process, which is responsible for forging pressure and frictional heat, while traverse and rotational speeds have the main effect on the traversing and lateral forces. The developed sensitized clamping system was used in support of welding process optimization to produce quality welds without resourcing to costly force control sensors. Using this device, it was possible to use force as a welding parameter and produce strong welds with mechanical behavior close to the parent materials’.

Microstructures and mechanical properties of friction hydro-pillar processing overlap welding in API 5L X65 pipeline steel

This paper exhibits a novel in situ remediation technique named friction hydro-pillar process overlap welding (FHPPOW) to repair the through crack of the structures and components in the harsh environments. In the present work, the effects of welding parameters on the microstructures and mechanical properties of the welding joints are investigated. The defect-free joints can be obtained in a large process window with the rotational speed of 6000–7000 rpm and welding force of 20–40 kN. In the heat-affected zone (HAZ), the interface between the substrate and lap plate can be clearly distinguished. The microstructure of the weld is mainly consisted of the upper bainite. The hardness value in the welding zone is highest and is the lowest in the base material. The pull-out tests of all welds are failure in the stud. Results indicate that the good welding quality can be obtained in these welding conditions. The best results of the cruciform uniaxial tensile and the shear tests are 662.8 and 552 MPa, respectively. The favorable Charpy impact absorbed energy is 68.75 J at 0 °C. The fracture characteristic of Charpy impact tests is brittle fracture with a large area of cleavage.

Multi response optimisation of FSW while using dissimilar aluminium alloys

In recent times, focus has been on developing fast and efficient processes that are environment friendly. The spotlight has been turned on 'friction stir welding' as a joining technology, capable of providing welds that do not have defects normally associated with fusion welding processes. From the available literature, it has been observed that the effect of welding parameters on desired characteristics was determined by taking into consideration one parameter at a time or by using conventional methods. So without ignoring the limitations of earlier researches, the main focus in this study has been kept on welding of dissimilar aluminium alloys (AA6061 and AA5086) by using design of experiments which is quite rarely used multi-factor at a time technique. Tensile strength and hardness were identified as key mechanical properties and were optimised upto 0.156 KN/mm2 and 73.19 HVN respectively. The fractional factorial design has been used to achieve required optimisation by using software 'Minitab-16'.

Microstructure and mechanical properties of laser welded joints between 2198/2060 Al–Li alloys

ABSTRACTDissimilar Al–Li alloys (2198 and 2060) were laser welded without the addition of filler material. The effects of welding parameters on the formation of the welded joints, microstructure evolution, solute segregation, porosity and their relationships with the mechanical properties of the joint were investigated. It was found that reducing the weld heat input can effectively prevent grain coarsening, while decreasing porosity and reducing the tendency for hot cracking, thereby enhancing the properties of the joint. The dissolution of precipitates such as the T1 phase and θ′ phase in the base metal, and the variations in Cu and Mg content between grain interiors and boundaries, resulted from solute segregation during welding, leading to reductions in the strength of the weld.

Effect of welding parameters on mechanical properties and microstructure of friction stir welded brass joints

Friction stir welding is a method developed for the welding of high-alloy aluminum materials which are difficult to combine with conventional welding methods. Friction stir welding of MS 63 (brass) plates used different tools (tapered cylindrical, tapered threaded cylindrical), tool rotational speeds (1040, 1500, 2080 rpm) and traverse speeds (30,45,75,113 mm.min−1). Tensile, bending, radiography and microstructure tests were carried out to determine the mechanical properties of brass plates joined by friction stir welding technique. Microstructure characterization studies were based on optical microscope and SEM analysis techniques. In addition, after joining operations, radiographs were taken to see the internal structure failure. Brass sheets were successfully joined to the forehead in the macrostructure study. In the evaluation of the microstructure, it was determined that there were four regions of base metal, thermomechanically affected zone (TMEB), heat-affected zone (HAZ) and stir zone. In both welding tools, the weld strength increased with increasing tool rotation speed. The particles in the stir zone are reduced by increasing of the tool rotation speed. Given the strength and % elongation values, the highest weld strength was achieved with tapered pin tool with a tool rotation speed of 1040 rpm and a tool feed speed of 113 min−1.

Effect of Welding Parameter on Dynamic Fracture Properties of 2024-T3 Aluminum Friction Stir Welded Joints

Friction stir welding is widely used in the aerospace structure. It is important to study mechanical response of aluminum welded joints under dynamic loading. This paper aims to investigate the effect of welding parameter on rate-dependent dynamic tensile properties of 2024 aluminum welded joints. Samples in different weld zones were designed and dynamic tests with different strain rates were performed. It is observed that as the non-uniform heat and plastic flow during welding, yield strength of the heat-affected zone (513MPa) is much higher than the stirred zone (370MPa) and the thermo-mechanically zone (336MPa). Under the rotation speed of 400rmp, the heat affected zone and the stirred zone show much better tensile ductility, which is 25% higher than that of samples welded with the 600rmp rotation speed. The strain rate strengthening effect is obviously obtained. Furthermore, 2024 aluminum has been considered to have low strain rate sensitivity. The fracture morphology of specimens shows that as the function of rotating tool, equiaxed and fine grains help to enhance the strength.

Multi response optimisation of FSW while using dissimilar aluminium alloys

In recent times, focus has been on developing fast and efficient processes that are environment friendly. The spotlight has been turned on 'friction stir welding' as a joining technology, capable of providing welds that do not have defects normally associated with fusion welding processes. From the available literature, it has been observed that the effect of welding parameters on desired characteristics was determined by taking into consideration one parameter at a time or by using conventional methods. So without ignoring the limitations of earlier researches, the main focus in this study has been kept on welding of dissimilar aluminium alloys (AA6061 and AA5086) by using design of experiments which is quite rarely used multi-factor at a time technique. Tensile strength and hardness were identified as key mechanical properties and were optimised upto 0.156 KN/mm2 and 73.19 HVN respectively. The fractional factorial design has been used to achieve required optimisation by using software 'Minitab-16'.

Microstructural and mechanical properties of Inconel 718 TIG weldments

Inconel 718 is widely used super alloy for high temperature applications in aeronautical and aerospace industries. The present work is to investigate the effect of welding parameters of Inconel 718 alloy welds in the tungsten inert gas (TIG) welding process. Post weld heat treatment (PWHT) was also carried out at 750°C/8h/furnace cooling followed by 650°C/8h/air cooling on the weldments. The microstructural and mechanical properties were studied in base metal (BM), weld zone and heat affected zone (HAZ) with different parameters. Based on the results, the welding parameters were fixed to get the optimum properties for Inconel 718.

Fabrication and Characterization of Weldments AISI 304 and AISI 316 Used in Industrial Applications

Gas tungsten arc welding (GTAW) and Shield metal arc welding (SMAW) are processed by using E347-16 electrode and filler wire to prepare the dissimilar weldments. The aim of study was to measure the effect of welding parameters: current, voltage, gas flow rate, nozzle to plate distance on tensile strength (TS), grain structure and hardness. The arc voltage and welding current was selected as 40,60 and 80V and 30,45 and 60amp respectively. The welding speed was selected as 4, 8, 12cm/sec. There is zero cracks, porosity, blow holes, spatter found in welding process of plate no. 2(AISI 304 &AISI 316 with ER-309L) using non consumable tungsten electrode with argon gas and also the microstructure study shows that the welding is self cooled welding structure with fine austenitic structure and very little heat affected zone found in this process. TIG welded dissimilar joint has best joint strength, uniform hardness variation as well as joint integrity.

Microstructure and mechanical properties of friction welded AISI 1040/AISI 304L steels before and after electrochemical corrosion

Abstract The aim of the present study is to investigate the effect of welding parameters both on the electrochemical corrosion behavior and tensile strength of pre- and post-electrochemical corrosion of friction welded dissimilar steels. The microstructural changes of AISI 1040/AISI 304L friction welded couples and also parent materials were analyzed by using scanning electron microscopy. The electrochemical behaviors of AISI1040/AISI304L joints were comparatively investigated by potentiodynamic polarization curve test and by electrochemical impedance spectra. Moreover, tensile strength experiments were carried out determining the behavior of friction welded joints of pre- and post-electrochemical corrosion and results indicated that the maximum tensile test value of the dissimilar welded pre-electrochemical corrosion was higher than those of post-electrochemical corrosion and was also very close to AISI 1040 parent material value.

Non-dimensional modeling of the effects of weld parameters on peak temperature and cooling rate in friction stir welding

Experimental data from friction stir welded Al 7075 and HSLA-65 were used to create dimensionless, empirical models relating critical weld parameters to the peak temperature rise and cooling rate of the weld heat-affected zone. Five different backing plate materials and a wide range of travel speeds and weld powers were used in the experimental design to ensure the models are relevant to a broad range of welding parameters. The resulting models have R-squared values of 0.997 and 0.995 for the dimensionless peak temperature rise and cooling rate correlations, respectively. Demonstrations of the models’ practical applications are provided. Herein is shown how the models can identify welding parameter (i.e. travel speed or power) levels needed to produce a desired weld peak temperature rise or cooling rate. Also demonstrated is how the models can be used to explore the relative effects of travel speed and backing plate thermal diffusivity on weld peak temperature rise and cooling rate.

Semi-empirical modeling and parameter analysis for the development of a high speed resistance-welding process

This paper presents procedures for parameter analysis and modeling, which are applicable in the development and quality control of a high-speed-resistance welding process. Two test beds are introduced, which are used in the experimental investigation, particularly to establish efficient methodologies for welding wire mesh. Test data are acquired under different parameter settings. A linear test bed is used to establish preliminary parameter ranges for good welding. Then, the effect of welding parameters on rotary welding is studied using the second test bed. Finally, a semi-empirical model of the welding processes, which presents the relationship between the welding parameters and the welding quality, is developed. These results may be used as the basis for setting the operating parameters and for monitoring and controlling the quality, through a weld-quality index and appropriate control schemes, in a welding process.

Effects of Welding Parameters on Strength and Corrosion Behavior of Dissimilar Galvanized Q&P and TRIP Spot Welds

This study investigates the effects of the main welding parameters on mechanical strength and corrosion behavior of galvanized quenching and partitioning and transformation induced plasticity spot welds, which are proposed to assemble advanced structural car elements for the automotive industry. Steel sheets have been welded with different current, clamping force, and welding time settings. The quality of the spot welds has been assessed through lap-shear and salt spray corrosion tests, also evaluating the effects of metal expulsion on strength and corrosion resistance of the joints. An energy dispersive spectrometry elemental mapping has been used to assess the damage of the galvanized zinc coating and the nature of the corrosive products. Welding current and time have the strongest influence on the shear strength of the spot welds, whereas clamping force is of minor importance. However, clamping force has the primary effect on avoiding expulsion of molten metal from the nugget during the joining process. Furthermore, clamping force has a beneficial influence on the corrosion resistance because it mainly hinders the permeation of the corrosive environment towards the spot welds. Although the welded samples can exhibit high shear strength also when a metal expulsion occurs, this phenomenon should be avoided because it enhances the damage and vaporization of the protective zinc coating.

Effects of welding parameters on microstructures and mechanical properties of disk laser beam welded 2A14-T6 aluminum alloy joint

Disk laser beam welding technique is used to fabricate 2-mm 2A14-T6 aluminum alloy plates under different welding parameters. Effects of welding parameters on microstructures and mechanical properties of the weld are investigated. Grain size and porosity ratio in the disk laser welds firstly decrease, then increase with the increase of the heat input. Hardness at the fusion line and in fusion zone, tensile strength and elongation firstly increases, then decreases with the increasing heat input. When laser power is 2500W, welding velocity is 2.0m/min and heat input is 75kJ/m, the finest microstructures, the minimum porosity ratio, the highest hardness and the maximum tensile strength are obtained. The fracture type in all samples is defined as a ductile fracture, and the maximum tensile strength reaches up to 261.7MPa, about 61.2% of that of the base metal.