Combination Of Welding Parameters Research Articles

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.

Stress crack resistance of unaged high-density polyethylene geomembrane fusion seams

The stress crack resistance (SCR) of high density polyethylene (HDPE) geomembrane (GMB) fusion seams is examined for two 1.5 mm HDPE GMBs and a range of welding parameters. Results are reported for both unnotched and notched seams as well as their corresponding sheet material. Unnotched seam SCR specimens are shown to preferentially initiate craze formation at the terminating edge of the squeeze-out bead, while incorporating potentially degraded areas, such as the seams heat-affected zone (HAZ), within the slow crack growth region of the specimen. In the short-term, little variation was observed between the majority of seams for the nine welding parameter combinations examined, with an average normalized seam SCR value (normalized with respect to the unnotched sheet SCR) of 0.3 ± 0.1, or about 30% of the SCR of the unnotched sheet. It is shown that squeeze-out geometry plays an important role in the SCR of fusion seams. Seams with weld track rippling, a known qualitative indication of overheating, were found to have average unnotched SCR values 45% lower than smooth weld track seams. Deleterious squeeze-out geometries are identified to provide a framework through which CQA engineers and researchers can more readily identify ‘higher risk’ seams with respect to stress cracking.

OTOMOTİV SEKTÖRÜNDE KULLANILAN DİRENÇ NOKTA KAYNAK İŞLEM PARAMETRELERİNİN KAYNAK MUKAVEMETİ ÜZERİNE ETKİLERİNİN İNCELENMESİ

The most widely used welding joining method in the automotive industry is resistance spot welding. Resistance spot welding (RSW) is the welding area where heat is produced by the effect of resistance against the flow as a result of exposing the welded parts to a local electric current. It has become an important issue to apply an effective approach method to guarantee weld quality and optimize welding parameters. This is of high value in theory and practice. In the literature, the effects of spot welding process parameters on the weld core diameter and electrode penetration depth are mostly investigated. Weld strength in RSW is affected by many process parameters such as applied electric current, compression force, welding time. Due to the contact resistance and joule heating, a molten weld nugget zone is formed on the work pieces. It is desirable to have the maximum temperature at the interface of the parts to be joined. In practice, the production of welds of acceptable quality depends on the definition of optimum weld parameters and the application of appropriate controls to ensure constant weld quality over a long production period. In the experimental studies, the optimization of the welding parameters was studied in order to obtain the maximum tensile-shear strength. The most prominent process parameters in experimental studies are electrode force, welding currents and welding times. Different algorithms have been developed for the optimization of welding parameters. The verification tests clearly show that it is possible to increase the tensile-shear strength of the connection with the combination of appropriate welding parameters. As a result, the experimental results confirm the validity of the algorithms used to improve welding performance and optimize welding parameters in resistance spot welding processes.

Establishing optimal friction stir welding parameters for AA2219-T87 Al-alloy using comprehensive RSM and GA approach

AA2219-T87 aluminium alloy has been used in aerospace applications because of its high strength, low density and resistance to corrosion. The copper in the alloy improves the hardness and lowers melting point, which makes two sections easily joined with a process called friction stir welding of aluminium alloy. In the present work, heat-treated AA2219 alloy was butt welded by solid-state friction stir welding process. This work aims to develop a suitable combination of welding parameters for producing defect-free weld joints of AA2219 alloy to improve tensile and corrosion properties. The most influencing control parameter for optimising the friction stir welding responses was determined using sophisticated design of experiments (DOE) techniques. Ultimate tensile strength and corrosion resistance are observed as responses in this study. To achieve the desired weld responses, a three-factor, three-level Box-behneken design was used. Analysis of Variance (ANOVA) was carried out to examine the interaction effect and significant welding parameter to set the optimal level of welding conditions. Multi-response regression equations have been developed using response surface methodology (RSM) to estimate the output characteristics of weld. The Genetic algorithm (GA) was used to optimise the predicted mathematical model under given optimization constraints. The results shown that the optimum responses are obtained at input factors rotational speed 300 rpm, welding speed 80 mm min−1, and axial force of 10kN.

Optimum Welding Parameters for Friction Stir Welded AA6063 Pipe Butt Joint Using the Taguchi Method

Welding parameters for pipe joint friction stir welding (FSW) have been identified based on L-9 orthogonal arrays used in the Taguchi Method. Different welding parameters, such as rotation speed, travel speed and axial force, have been used to produce several quality friction stir welded AA6063 pipe butt joints. The reliability of products obtained in the FSW process can be improved through the identification of the optimum combination of welding parameters. Weld quality was evaluated based on its tensile strength and residual stress profiles. The S/N analysis and Analysis of Variance (ANOVA) have been used to determine significant welding parameters that affect weld quality. Maximum tensile strength with acceptable residual stress was obtained at the optimum welding parameters of 1300 rpm, 5 mm/s and axial force between 5 and 6 kN. The goal of this study was to optimize welding parameters for high tensile strength and low residual stress.

Correlation between GMAW Parameters and Mechanical Properties of Hot-Rolled, High-Strength Low-Alloy (HSLA) Steel Butt Joints

In all industrial fields, the product requirements are more and more demanding. HSLA steels are designed to provide higher atmospheric corrosion resistance and improved mechanical properties than structural steels. The paper presents the results of an experimental program based on factorial design, applied to predict the mechanical properties of butt-welded joints of S420MC and S460MC hot-rolled, high-strength low-alloy (HSLA) steel plates with 2mm, 4mm and 8mm thickness. Gas Metal Arc Welding (GMAW) was used and correlations between the main process parameters and the related mechanical properties of the welded joints were found. Obtained mathematical correlations can be exploited to provide optimal combination of welding parameters to fit the quality requirements of the end-users for envisaged welded product.

A cost-function driven adaptive welding framework for multi-pass robotic welding

• An adaptive cost driven welding framework for automated multi-pass welding is introduced. • Welding parameters can be optimized by minimizing a user selectable weighted cost function. • The generation and adaption of welding parameters per layer for varying V-groove joints is presented. • Robotically experimental verification on welded joints of single sided V geometries is shown. • Ultrasonic inspection is utilized to validate the quality of the weldments. Manual teaching of robot paths and welding parameters for multi-pass robotic welding is a cumbersome and time-consuming task, which decreases the flexibility, adaptability, and potential of such systems. This paper introduces and presents a new automated weld parameter and pass deposition sequencing framework, which builds on the current state of the art developments and enables automatic planning of multi-pass welding for single-sided V-groove geometries. By integrating a novel cost-function concept that permutates and identifies the welding parameters for each layer through a user-driven weighting, the framework delivers the minimum number of passes, filler material and welding arc time based on application requirements. A mathematical model relating the cross-section area of beads with the pose of the torch and weaving width was built upon to allow full-process automated welding parameter generation and adaption for different geometric characteristics of the groove. The concept methodology and framework were then developed and verified experimentally, through robotically deployed Metal Active Gas (MAG) welding. For a given representative joint, the arc welding time and amount of filler wire were found to be 32.9 % and 26.18 % lower respectively, than the worst-case available welding parameter combination, delivering a corresponding decrease in direct automated welding manufacturing costs. Lastly, an ultrasonic inspection was undertaken to verify the consistent quality of the weldments validating the framework outcome and enabling welding pass automation through robotic systems.

Optimization of friction stir welding parameters of dissimilar aluminium alloys 6061 and 5083 by using response surface methodology

Aluminium and its alloys are lightweight, corrosion-resistant, affordable and high-strength material and find wide applications in shipbuilding, automotive, constructions, aerospace and other industrial sectors. In applications like aerospace, marine and automotive industries, there is a need to join components made of different aluminium alloys, viz. AA6061 and AA5083. In this study friction stir welding (FSW) is used to join dissimilar plates made of AA6061-T6 and AA5083-O. The effect of varying tool pin profile, tool rotation speed, tool feed rate and tilt angle of the tool has been investigated on the tensile strength and percentage elongation of the welded joints. Box-Behkan design, with four input parameters and three levels of each parameter has been employed to decide the set of experimental runs. The regression models have been developed to investigate the influence of welding variables on the tensile strength and elongation of the welded joint. It is revealed that with the increase in welding parameters like tool rpm, tool feed rate and tilt angle of the tool, both the mechanical properties increase, reach a maximum level, followed by a decrease with further increase in the value of parameters. Amongst different types of tool pin profiles used, the FSW tool having straight cylindrical (SC) pin profile is found to yield the maximum strength and elongation of the welded joint for different combinations of welding parameters. Multiple response optimization indicates that the maximum UTS (135.83 MPa) and TE (4.35%) are obtained for the welded joint fabricated using FSW tool having SC pin profile, tilted at 1.11° and operating at tool speed and feed rate of 1568 rpm and 39.53 mm/min., respectively.

Optimasi parameter resistance spot welding pada pengabungan baja electro-galvanized menggunakan metode Taguchi

The present study features analytical and experimental results of optimizing resistance spot welding performed using a pneumatic (electrode) force system (PFS). This optimization was carried out to incorporate the galvanized steel sheet material SECC-AF (JIS G 3313) and SPCC-SD (JIS 3141) sheet plate coated with zinc with a thickness of about 2.5 microns. The zinc coating on the metal surface causes its weldability to decrease. This study aims to obtain the highest tensile shear strength test results from the combination of the specified resistance spot welding parameters. The research method used the Taguchi method using four variables and a combination of experimental tingkats. This study's experimental tingkat is two tingkats in the first parameter and three tingkats in other parameters. Taguchi optimization results show that the highest tensile shear strength test obtained is 5049.64 N. This was achieved at 22 cycles of squeeze time, 25 kA of welding current, and 0,6-second welding-time, and 12 cycles of holding-time. The S / N ratio analysis found that the welding time had the most significant effect, followed by welding current, holding time, and squeeze time. The delta S / N ratio values were 0.62, 0,41, 0.34 and 0.07, respectively.

The use of TOPSIS-based-desirability function approach to optimize the balances among mechanical performances, energy consumption, and production efficiency of the arc welding process

A couple of models were established to investigate the effects of welding parameters (voltage, wire feed speed, and welding speed) on the resultant mechanical properties of welding bead and welding heat input on the basis of a Box-Behnken experimental design (BBD). The three key mechanical parameters, that is, maximum displacement, peak load, and energy absorption, were processed via the technique in order of preference by similarity to ideal solution (TOPSIS) and Shannon entropy technique. After that, the correlations among the mechanical properties, welding heat input, and three technological variables in the welding process were established herein. Analysis of variance (ANOVA) implied that the heat input relied on voltage, welding speed, wire feed rate, and the interaction effects among these factors. These models act as the basis to achieve the multi-objective optimization problem by the desirability function approach. Results suggest that the welding settings favoring a robust trade-off between minimum welding heat input and maximum mechanical properties involve an intermediate value of wire feed speed, a high value of voltage, and welding speed. This welding parameter combination not only can produce an optimum welding bead with robust mechanical performances but also guarantees the goal of optimum welding heat utilization and production efficiency, in which the high level of welding speed is strongly recommended.

Imperfections and Modelling of the Weld Bead Profile of Laser Butt Joints in HSLA Steel Thin Plate

In many applications that use high strength steels, structural integrity depends greatly on weld quality. Imperfections and the weld bead geometry are influencing factors on mechanical properties of the welded joints but, especially in the fatigue strength, they cause a great decrease. The proper knowledge of these two factors is important from the nominal stress approach to the fracture mechanics approaches. Studies concerning the profile and imperfections of the weld bead in laser welding for thin plates of high strength steels are scarce. In this work, these two aspects are covered for five series single and double-welded joints, butt joints in a 3 mm thick HSLA steel, welded in a small range of welding parameters. The actual profiles captured with profilometer were modeled with proposed geometric parameters achieving an adequate fit with values of the coefficient of determination ℜ2 greater than 0.9000. Description of imperfections includes the distributions of porosity and undercuts. The evaluation of the weld quality, taking as guide the ISO 13919-1 standard determined B and D levels for the welded series while based on the stress-concentrating effect, showed a greater detriment in those series with undercuts and excessive penetration. The analysis of variance validated the results of the different combinations of laser welding parameters and showed, for the factorial experimental design, a more significant effect of the welding speed.

Experimental and numerical study to minimize the residual stresses in welding of 6082-T6 aluminum alloy

One of the most important negative consequence in the fusion welding processes is the generation of tensile residual stresses in welded joints. The main goals of this work are to determine the optimal combination of welding parameters to minimize the residual stress level and the influence of each welding parameter in that feature to weld 6082-T6 aluminum alloy plates using the GMAW welding process. To achieve these goals was implemented the Taguchi orthogonal array (L27) to define the design of numerical and experimental tests. All combinations were simulated in the Simufactwelding 6.0 software, from which it was possible to obtain the values of maximum residual stresses. The data treatment was carried out, reaching the combination of levels for each parameter. With ANOVA analysis was found that the parameter with the greatest influence in the residual stress generation was the welding speed, while the parameter with the least influence was the torch angle. Also, to minimize the residual stresses it was observed that the optimal combination of welding parameters is welding current intensity of 202 A, welding speed of 10 mm/s, and 30° of inclination of the angular torch. The two simulations that resulted in the highest and lowest residual stresses were validated experimentally by the hole drilling method to measure the residual stresses.

Optimization of process parameters in friction stir welded dissimilar magnesium alloys using RSM

The welding of two dissimilar magnesium alloys is considered as a greatest challenge because of poor metallurgical transition at joints. The FSW process is mostly used for joining different metals which are very difficult to weld through fusion welding technique. In this study the FSW process is used to weld AZ31B and AZ91C magnesium alloys. Three different tool profile (Conical, square and cylindrical type) were used along with three different rotational speeds (900, 1150 and 1400 rpms) and tool traverse speeds (25, 35 and 45 mm/min). The tensile strength was experimentally calculated for all the 15 combinations given by the Box – Behnken model in response surface methodology technique. Three samples in each combination were tested and the average tensile strength was used to find the optimized welding parameters combination in response surface methodology software. The microstructure of the welded region was analysed using scanning electron microscopy to verify the effect of brittle inter – metallic transition at welded joints. The regression equation generated from the Box – Behnken model was used to find the optimized parameters condition. The optimized tensile strength value of 186.721 was obtained from Response Surface Methodology at an optimum parameter combination of a tool rotation speed at 900 rpm with square tool pin head of 45 mm tool traverse speed. The conformal experiment was performed to verify the accuracy of the optimized parameter combination. The conformity test results showed a tensile strength of 182.57 MPa with an error percentage of 2.2% from proposed optimization value which confirms the scope of this study in end functional applications.

Shear strength optimization for FSSW AA6060-T5 joints by Taguchi and full factorial design

Statistical tools have shown to be very useful in the optimization of processes such as welding. Optimization is understood as the determination of the welding combinations that will lead to the maximization of a desired property, such as strength. This work proposes a statistical methodology to determine the optimum combination of welding parameters of FSSW in 6060-T5 aluminium alloy. Two Design of Experiment (DOE) statistical tools, Taguchi and Full Factorial Design (FFD) were used to determine the optimum combination of three welding parameters: rotational speed, plunge rate and dwell time. Four samples were produced for each welding combination and then subjected to shear test to evaluate joint strength. Quadratic regression was used to obtain an equation correlating joint strength and welding parameters. With the methodology presented, it was obtained an equation to correlate welding parameters and joint strength with acceptable accuracy. The results have shown that a proper combination of DoE tools like Taguchi and FFD is key to determining the optimum set of welding parameters in the FSSW process.

Optimization of Tensile-Shear Strength in the Dissimilar Joint of Zn-Coated Steel and Low Carbon Steel

The present study features analytical and experimental results of optimizing resistance spot welding performed using a pneumatic force system (PFS). The optimization was performed to join SECC-AF (JIS G 3313) galvanized steel material with SPCC-SD low carbon steel. The SECC-AF is an SPCC-SD (JIS G 3141) sheet plate coated with zinc (Zn) with a thickness of about 2.5 microns. The zinc coating on the metal surface causes its weldability to decrease. This study aims to obtain the highest tensile-shear strength test results from the combination of the specified resistance spot welding parameters. The research method used the Taguchi method using four variables and a combination of experimental levels. The experimental levels are 2-levels for the first parameter and 3-levels for other parameters. The Taguchi optimization experimental results achieved the highest tensile-shear strength at 5049.64 N. It properly worked at 22 squeeze time cycles, 25 kA of welding current, and 0.6-second welding time and 12 holding-time cycles. The S/N ratio analysis found that the welding current had the most significant effect, followed by welding time, squeeze time, and holding time. The delta S/N ratio values were 1.05, 0.67, 0.57 and 0.29, respectively.

Determination of Optimum Process Parameters and Residual Stress in Friction Welding of Thixocast A356 Aluminum Alloy

The quest of automobile industries for weight reduction and enhancement of the mechanical strength of components has been a major incentive for new manufacturing technologies such as thixocasting. It is therefore important that the welded joints of such components exhibit adequate strength and formability. The present investigation is on optimization of process parameters to achieve better weld quality obtained in friction-welded joints of thixocast A356 aluminum alloy. The optimum combination of welding parameters is obtained by using the analysis of the signal-to-noise (S/N) ratio based on the Taguchi method. Joint strength higher than the parent material strength is achieved with an optimum set of friction-welding parameters. In addition, residual stress analysis is carried out both experimentally and numerically. Comparisons between the experimental and numerical residual stresses are in good agreement with each other. The residual stress obtained is of low magnitude and compressive in nature.

Effect of Metal Inert Gas Welding Process Parameters to Tensile Strength on ST 37 Steel Sheet Joint

Welding technology still used in manufacturing industries, however welding process affected to decrease a joint performance. This study discussed about the welding parameters of Metal Inert Gas (MIG) which affected to tensile strength of weld joint. Welding process parameters used in this study such as welding current, welding time, and welding speed. The level of welding current was 80 A, 90 A, and 100A. Wire Speed was leveled with 55 inch/min, 60 inch/min, and 65 inch/min. The levels were 5 mm/sec, 6 mm/sec, and 7 mm/sec as welding speed. Tensile testing was used to measure strength of weld joint joined by each welding parameters combination. Welding current 100 A, wire speed 60 inch/min, welding speed 5 mm/sec could join ST 37 steel sheet up to 51.41 kg/mm2 of tensile strength. Welding current affected to increase tensile strength when values of welding current were increased between 80 A and 100 A….