Combination Of Welding Parameters Research Articles

Long-term performance of HDPE extrusion welds aged at 85°C in synthetic leachate

The effect of ageing at 85°C of extrusion welds of 1.5 mm-thick high-density polyethylene (HDPE) geomembrane, immersed in synthetic municipal solid waste leachate, is investigated with respect to its standard oxidative induction time (Std-OIT) and stress crack resistance (SCR). Results show that the heat-affected zones (HAZ) adjacent to the squeeze-out bead (flashing) may exhibit faster STD-OIT depletion than the sheet. Generally, individual weld SCR failure times were observed to be between that of the notched and unnotched sheet. Welds with high welding-induced geometric irregularities (WIGI), and overheated fusion and extrusion welds are shown to result in SCR failure times close to that of a notched sheet. The average time to nominal failure (taken to be when tNF = 250 h) of Cool and Good welding parameter combinations ranges between 3% and 15% shorter than the unnotched sheet. Differences in tNF were attributed to accelerated craze formation in welds with high WIGI from stress concentration. No significant difference was observed between the SCR values of fusion and extrusion welds during 40 months of immersion in MSW-L3. This paper shows that overgrind negatively impacts the SCR of welds and accelerates the degradation of SCR.

Optimization of Welding Parameters for Minimizing Defects and Porosity in Electric Arc Welding of Mild Steel Grade Fe 500 Using of Taguchi Method

Abstract: Electric arc welding is a widely used technique in industrial applications for joining metals, including mild steel grade Fe 500. However, the process is susceptible to defects such as porosity, which can compromise the integrity and quality of welds. In this study, we investigate the optimization of welding parameters to minimize defects and porosity in electric arc welding of mild steel grade Fe 500, utilizing the Taguchi method. The Taguchi method, known for its efficiency in optimization studies, is employed to systematically identify the most influential welding parameters and their optimal levels. Through a series of experiments based on the Taguchi orthogonal array design, we vary parameters such as current amperage, voltage, and electrode size to explore their effects on weld quality. The experimental results reveal significant insights into the relationship between welding parameters and defect formation. By analyzing signal-to-noise ratios and ultimate tensile strength, we quantify the effects of parameter variations on weld quality. The Taguchi analysis enables us to identify the optimal combination of welding parameters that minimizes defects and porosity while maximizing weld strength.

Bead geometry prediction and optimization for corner structures in directed energy deposition using machine learning

Wire Arc Additive Manufacturing as a Directed Energy Deposition technology has disruptive potential for modern manufacturing. The technology comes with the flexibility and material efficiency of additive manufacturing processes while mitigating the disadvantages through high material deposition rates and high energy efficiency. However, the prevalence of the technology is inhibited by its geometrical inaccuracy and the large induced residual stresses. This work tackles the former problem by capturing the process parameter-geometry relationship using Machine Learning. To do so, multiple mild steel welding beads with varying shape features like corner angles are printed using a Metal Inert Gas welding machine attached to an industrial robot. The cross-sectional profile of the printed beads is measured using a point laser sensor and correlated through a Multilayer Perceptron to input features such as travel speed, wire feed speed, and shape features. By incorporating varying corner angles, a holistic model, not limited to geometry prediction of straight beads only, is trained. Using the model, excess material at the inner angle of corners determined by the overlapping regions of the two adjacent beads can be predicted. By generating a database of possible bead shapes an inverse algorithm that suggests welding parameter combinations that yield a smooth bead shape at the corner is created, thus enabling improvement of the overall accuracy of the Wire Arc Additive Manufacturing process.

Experimental Analysis on Mechanical Properties with Microstructures on Aluminium alloy 6070 Welds with H14 Steel

bstract: TIG welding stands out as a highly precise and efficient welding technique, proficient in joining both ferrous and nonferrous metals. This method offers exceptional control, produces minimal fumes and spatter, and results in a clean weld that often requires little to no finishing. The focus of the current research is on determining the optimal combination of welding parameters for TIG welding of Al6070 and H14 materials. The literature survey reveals the inherent difficulty of welding aluminium using conventional arc welding processes. A multitude of welding parameters significantly influences both the quality of the welds and their repeatability. This study systematically investigates various parametric ranges and their effects. The TIG welding setup employed in this specific study will weld 10mm thick Al6070 and H14 plates, adhering to the prescribed welding parameters. The impact of these parameters on the tensile and impact strength of the welding joints, as well as the microstructural characteristics, will be thoroughly analysed.

Effect of welding parameters on properties of HDPE geomembrane extrusion welds

The stress crack resistance (SCR) of high-density polyethylene (HDPE) geomembrane extrusion welds is examined for a 1.5 mm HDPE geomembrane and three different welding parameter combinations (denoted as “Cool”, “Good”, and “Overheated”). Results are reported for unnotched welds, unnotched sheet, and notched sheet. The average SCR for a Good extrusion weld is 23% of that of the unnotched sheet SCR. Little variation is found between the three welding parameter combinations for low geometry irregularity SCR weld specimens. There is no statistically significant difference between a good-quality fusion and extrusion weld. However, operator-dependent weld induced geometric irregularity (WIGI) greatly affects the SCR of extrusion welds. Extrusion welds with high WIGI have an average unnotched SCR of only 9% of the unnotched sheet. Extrusion welds with an overground surface can have an unnotched SCR as little as 1% of the best extrusion weld. Deleterious weld bead geometries are identified to provide a framework with which engineers can identify “high-risk” extrusion welds with respect to stress cracking.

Resistance-welded thermoset composites: A Bayesian approach to process optimisation for improved fracture toughness

Joining thermoset composites via resistance welding offers a novel highly efficient assembly method for next-generation aerospace structures. Resistance-welded joints combine the benefits of bonding with the capacity for high-volume manufacturing rates and eliminate the need for complex surface preparation. The influence of key welding parameters on the joint performance is investigated by assessing the Mode I fracture toughness. Double Cantilever Beam specimens with different welding parameter combinations are manufactured, tested and compared with each other. Thermoset laminates are made weldable by co-curing a chemically compatible thermoplastic film with an uncured thermoset laminate. A Bayesian approach is used to study the correlation between processing parameters and to select parameters yielding high performance by training a Gaussian process emulator. Observed Mode I fracture toughness values are comparable to high-performance thermoplastic composites. This is equivalent to an improvement of approximately 290% in Mode I fracture toughness when compared to a co-cured thermoset joint.

Microstructure and texture evolution of friction stir lap welded dissimilar multi‑aluminum stack

This work investigates the microstructural evolution of a dissimilar multiple‑aluminum alloy stack (AA7055, AA7055, AA6022) produced by friction stir lap welding (FSLW). A through-thickness analyses of grain orientation map, grain size and distribution, strain distribution, and texture evolution by electron backscattered diffraction-based characterization technique were performed. Two different welding parameters (combination of tool rotation and traverse speed) were used to study the effects of the welding parameters on these microstructural characteristics. The study shows that higher welding speed and higher rotation speed of the FSLW tool yield finer grains. FSLW resulted in shear texture formation in the weld regions due to high welding speeds. This texture development in the nugget zone is consistent with shear deformation, and (111) pole figures show ideal shear texture components. The Stir Zone (SZ) exhibits shear texture (A/A ̅ and B/B ̅ components), consistent with other shear-assisted processes. Recrystallization mechanisms observed are CDRX in SZ and DDRX in TMAZ (Thermo-Mechanically Affected Zone). Interface analysis reveals the presence of oxide layers between different aluminum sheets, affecting joint mechanical performance. The mechanical property of the lap welded joints was presented in terms of microhardness distribution across the weld cross section. Slightly higher hardness in higher speed welding setup was observed throughout the SZ and AA6022 layer, indicating greater grain refinement and uniform grain structure distribution.

Parameter optimization in DP-TIG welding of SMO 254 using TOPSIS

An optimized welding parameter combination is vital for successful weld joints therefore an effort was made to determine the parameters. Square butt joint welding trials were performed on SMO 254 thickness 4 mmby the Double Pulse-TIG welding process (DP-TIG) with ERNiCrMo-10 (Alloy C22) filler. Topick out the optimized parameters association the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS)methodology was applied. Moreover to that Analysis of Variance (ANOVA) was utilized to determine the most significant parameters on the overall many objective function. The outcome of ANOVA showed that pulse ratio and mean current had substantial dominance on the overall many objectivefunctions.

High Cycle Fatigue Testing of Lap Shear RSW Joints from Martensitic MS1400 Steel Sheets

Resistance spot welding (RSW) is one of the most common welding methods for steel sheets, as it is mainly used to join the automotive body structure parts. Different types of ultra-high strength steels (UHSS) have become widely used in the automotive body to obtain the required demands such as lower car weight, improving crashworthiness behavior, and enhancing strength–ductility combination. Martensitic UHSS belong to the highest grades width their tensile strength above 1000 MPa. During the lifetime of the vehicle cyclic loading generally occurs, therefore the optimization of welding technology should be performed considering the fatigue resistance of the welded joints. In our research 1 mm thick standardized lap shear sheets of martensitic MS1400 steel were welded by a TECNA 8007 RSW equipment with two different welding parameter combinations. The idea was to analyze the effect of welding and pulsation parameters on joint properties under static and cyclic loading. The welding parameters have been calibrated to produce the same weld nugget size for both technological combinations. Macroscopic, hardness, and tensile-shear tests were carried out to determine the fundamental mechanical characteristics of the RSW joints. The relation between the weld nugget microstructure and mechanical properties was explored. The high cycle fatigue (HCF) tests were performed on an MTS 810.23 universal electro-hydraulic materials testing system. A statistical approach was applied during the preparation and evaluation of the investigations, which increased their reliability. Measured and analyzed data of the lap shear welded joints, prepared by different technological parameters, were compared and discussed. The parameters of the HCF experiments were calculated considering the Japanese testing method (JSME S 002-1981). In most of the samples it was observed from both welding parameter combinations that the fatigue cracks initiate and grow in curvature shape in the softened part of the heat-affected zone towards the base metals in both directions symmetrically. A slight difference was observed in the HCF resistance of the welded joints prepared by different welding parameters.

Dissimilar linear friction welding of Ni-based superalloys

Linear friction welding is a solid-state, near-net shape manufacturing method for metallic alloys which is characterised by complex deformation and metallurgical actions at the weld interface. However, a lack of understanding of the welding parameter interaction and subsequent welding mechanisms is hindering the joint integrity enhancement of dissimilar linear friction welding. In this study, we investigated the influence of various process parameters on macro/micro-formation, microstructural evolution, and properties to establish optimal welding conditions for the sound linear-friction-welded joint integrity of dissimilar superalloys, IN718, and the powder metallurgy FGH96. Increased oscillation frequency or decreased applied pressure promoted continuous dynamic recrystallisation and grain refinement, although discontinuous dynamic recrystallisation remained dominant. Enhanced dissolution of the strengthening phases (γ′ phase on the FGH96 side and δ phase on the IN718 side) was observed from the thermomechanically affected zone to the interface. The subsequent correlation between the microstructure and mechanical properties indicated that solid–solution strengthening was the dominant mechanism for enhancing interfacial bonding, which was promoted by mutual material deformation on both sides. Accordingly, to achieve synergistic plastic deformation in dissimilar linear friction welding, an optimisation strategy of welding parameter combination was proposed and validated by investigating hot compressive dissimilar Ni-based superalloys. The results of simulations of sub-size workpieces showed that using linear friction welding to manufacture bimetallic bladed disks, from conception to completion, was feasible. The paper offers an integrated solution for the full-scale manufacturing of an IN718/FGH96 blisk using linear friction welding based on microstructure–property interactions and relevant simulations, which can ideally serve as the basis for future bimetallic bladed disk manufacturing.

Experimental investigation and numerical analysis using Taguchi and ANOVA methods for underwater friction stir welding of aluminium alloy 2017 process improvement

The effect of under water friction stir welding for 5 mm AA2017 aluminum alloy plaque on mechanical properties has been examined and optimized. Nine different tests were designed according to Taguchi orthogonal array without changing the welding tool. Three variable operating parameters (Welding velocity, rotational velocity and axial force) have been used with three levels for each parameter. The effects of each FSW parameters on the weld joint were discussed and analyzed, the analysis of variance (ANOVA) is adopted to identify the contribution of each FSW underwater parameters. Moreover, the statistical Taguchi method (TM) was employed to pridect the optimal combination of welding parameters to improve the tensile properties such astensile strength (TS) of welded joints. In addition, the experimental tests show good agreement with that obtained by the proposed mathematical model. Wherethe obtained validation results confirm the robustness of the optimization method as a useful tool to improve the quality responses of underwater friction stir welding.

Visual inspection on friction stir welded dissimilar aluminum alloy AA6082-AA5083 using conventional and hybrid tool pin profiles

Friction stir welding (FSW) is a solid-state joining technique. One of the major areas where FSW finds a key role in applications is aerospace and automobile sector. FSW is not a defect free welding process. FSW weldments might have surface defects if the combination of welding parameters like tool rotational speed, weld speed, axial load and tool tilt angle does not provide an adequate amount of heat. In this study, a new concept has been developed by combining two tool pin profiles into a one as a hybrid tool pin. A visual inspection has been carried out on dissimilar aluminum alloy AA6082-AA5083 weldments produced by using the triangular tool pin and hybrid tool pin profiles. Surface defects like flash, lack of fill, fin-like flash and burrs were observed on the weldments.

Mechanical Characterization of Rotary Friction Welded Dissimilar Aluminium Alloys

Joining of the similar & dissimilar materials alloys using heat of the friction in currently being used, especially for non-ferrous alloys which are considered as non-weldable alloys. Al 2024-T6 & Al 6061-T6 having length of 70mm and 12mm diameter were welded by using the friction welding process. Similar and dissimilar welded samples were obtained by applying different combinations of welding parameters like friction pressure 30bar, forging pressure from 50 to 60 bar, and rotational speed of 2200 rpm. Vickers microhardness and Tensile test was performed on similar and dissimilar welded samples. Test shows that ultimate tensile strength and hardness of the similar welded joint was greater than their respective base metals welds. Dissimilar weld samples have hardness and ultimate tensile strength greater than the base Al 6061-T6, and less than the base Al 2024-T6. From results, it was clearly shown that as forging pressure increased from 50 to 60 bar, ultimate tensile strength and hardness of the similar and dissimilar welded samples increased. Joints were analysed to investigate the fractography of all welded samples. All welded samples fractured on the base metal alloy and show the formation of the cup and cone like structure which indicate the ductile fracture of the joints.

Parameter optimization and microstructure evaluation of welding of structural steel 1020 and AA6062

AA6062 and ST1020 materials are used to perform friction stir spot welding (FSSW). In this experiment, the mechanical and microstructural characteristics of the welded joint were determined using a square-head tip tool. To enhance the life of the welded joint, three essential process parameters, namely tool speed, dwell time, and plunge depth were employed with four levels. The L16 orthogonal array was adapted for experimental work to develop a process parameter table. A tensile test was performed for a larger better value to predict the strength of the welded joint, and the value is 5.65 kN. The outcome shows that dwell time is a more prominent parameter than tool speed and plunge depth. The optimal combination of welding parameters is a dwell time of 24 s, a tool rotational speed of 1200 rpm, and a plunge depth of 0.8 mm; dwell time contributes 39.66%, followed by a plunge depth 35.7%, and at last, tool speed 6.171%. Furthermore, to determine the optimum level of parameters. The microstructure of this joint was observed with respect to heat dissipation and changes in grain size. Microstructure studies were carried out to see the area under stir zone for workpieces with high and low tensile strength. This work was validated using the response surface method (RSM). The RSM results are very close to the experimental results.

Weldability of irradiated Stainless Steel 304 materials harvested from the National Research Universal (NRU) reactor

The weldability of the neutron-irradiated Stainless Steel 304 (SS 304) materials containing estimated helium levels of 12 to 44 appm has been studied through a Collaborative Research and Development Agreement between the Canadian Nuclear Laboratories and Oak Ridge National Laboratory. The work utilizes a SS 304 component harvested from the National Research Universal reactor. Laser beam welding was used to explore suitable welding conditions and associated parameters, to determine helium concentration limits for successful welding of irradiated stainless-steels. The experimental results show that maximum fusion zone void sizes, fusion zone void quantity and total heat affected zone helium-induced crack length generally increased with increasing He levels and effective weld heat input. A proper combination of welding parameters with low effective heat input, such as, laser power, weld travel speed and wire feed speed, were shown to improve the welding quality, and potentially reduce the length and probability of the formation of grain boundary helium-induced cracking and voids of irradiated SS 304 even with He concentrations as high as about 44 appm.

Optimizing Ultrasonic Welding Parameters for Multilayer Lap Joints of PEEK and Carbon Fibers by Neural Network Simulation.

The aim of this study is to substantiate the use machine learning methods to optimize a combination of ultrasonic welding (USW) parameters for manufacturing of multilayer lap joints consisting of two outer PEEK layers, a middle prepreg of unidirectional carbon fibers (CFs), and two energy directors (EDs) between them. As a result, a mathematical problem associated with determining the optimal combination of technological parameters was formulated for the formation of USW joints possessing improved functional properties. In addition, a methodology was proposed to analyze the mechanical properties of USW joints based on neural network simulation (NNS). Experiments were performed, and threshold values of the optimality conditions for the USW parameters were chosen. Accordingly, NNS was carried out to determine the parameter ranges, showing that the developed optimality condition was insufficient and required correction, taking into account other significant structural characteristics of the formed USW joints. The NNS study enabled specification of an extra area of USW parameters that were not previously considered optimal when designing the experiment. The NNS-predicted USW mode (P = 1.5 atm, t = 800 ms, and τ = 1500 ms) ensured formation of a lap joint with the required mechanical and structural properties (σUTS = 80.5 MPa, ε = 4.2 mm, A = 273 N·m, and Δh = 0.30 mm).

Influence of heat input on the appearance, microstructure and microhardness of pulsed gas metal arc welded Al alloy weldment

In order to achieve high-quality welding of aluminum alloys, reasonable control of welding heat input is critical. Different combinations of welding parameters can achieve the same heat input, however, the relevant research results has not been reported. In this paper, the pulsed-gas metal arc welding (P-GMAW) of 4047 Al–Si alloy was used as the research object. Combining design of welding current, welding voltage and welding speed, three sets of welding parameters with the same heat input were obtained, and welding experiments were carried out on them. The formation, microstructure and mechanical properties of weld bead were analyzed. The results show that under the same heat input, the effect of the welding current and voltage on the weld bead is remarkable. With the increase of the two, the penetration, width and spreadability of the weld bead increased, and the low melting point precipitates became more aggregated. At the same time, the average hardness of the weld increased from 98.27 HV to 104.4 HV, i.e., 6.2%.

Long-term stress crack resistance of HDPE fusion seams aged at 85 °C in synthetic leachate

The stress crack resistance (SCR) and standard oxidative induction time (Std-OIT) reduction of high- density polyethylene (HDPE) geomembrane (GMB) fusion seams is examined for a 12-year old 1.5 mm HDPE GMB when welded using nine welding parameter combinations. The GMB experienced a decrease in Std-OIT from 135 to 87 min between manufacturing and welding. Welding did not significantly decrease the Std-OIT in the heat-affected zone (HAZs). In general, individual seam SCR failure times fell between the notched and unnotched sheet, with adhered squeeze-out bead seams exhibiting individual failure times closer to the notched sheet and an average time until nominal failure ( tNF) ∼21%–35% shorter than the unnotched sheet. Differences in tNF are attributed to residual stresses and (or) accelerated craze formation in seams with adhered squeeze-out beads. Non-adhered squeeze-out seams exhibited a slower tNF similar to that of the unnotched sheet, indicating a seam tNF less than that of the sheet may not be intrinsic to all HDPE fusion seams. High sheet temperatures at the time of welding and higher heat-applied welding parameters are thought to increase the likelihood of squeeze-out bead adherence. This paper shows that squeeze-out adherence can have a deleterious effect on seam SCR.

INVESTIGATION ON EFFECT OF PULSED CURRENT MICRO PLASMA ARC WELD PARAMETERS ON UNS S32750 SUPER DUPLEX STAINLESS STEEL SHEETS

In this paper, a 0.33mm thick UNS S32750 super duplex stainless steel sheet is butt welded with welding with a micro-plasma arc. Peak current, base current, pulse width, and pulse rate are regarded welding input factors, whereas the tensile strength and hardness of the welded joint are known as output parameters. 31 distinct combinations of tests are carried out by integrating the response surface method (RSM) with central composite design (CCD) and taking into account four factors and five levels of weld process parameters. The main plots are used to visualize the variance in output responses as a function of weld input parameters. MINITAB software is used to establish mathematical models that take into account linear functions. At a 95% confidence level, ANOVA is used to compare two variables. The dominant parameter is identified using contour plots, and the optimum combination of welding parameters is determined using surface plots. Various welding parameters and their effect on stainless duplex steels have been comprehensively explored in this study.

Numerical investigation of dissimilar friction stir welding of AISI 304L and 410S stainless steels

Friction stir welding (FSW) has been successfully used to join dissimilar materials with advantages such as incipient chemical mixing and positive recrystallization of the microstructure. However, to understand how welding parameters affect the thermal cycle and the material flow around the tool is essential to produce joints without defects. In this work, a numerical simulation of dissimilar joints of AISI 304L austenitic stainless steel with AISI 410S ferritic stainless steel using the FSW technique was performed. The equations of the model were discretized by the finite volume method (FVM), and the mixture between the materials was modeled by the volume of fluid method (VOF) using the ANSYS-fluent simulator. The results predicted the temperatures during the welding for different conditions and viscosity changes successfully. Furthermore, they predicted a better combination of welding parameters in relation to flash formation. The VOF method predicted the mixture of the materials. Furthermore, the results indicated the location of each material and thus avoided unnecessary experimental tests.