Selection Of Welding Parameters Research Articles

Improvement of friction spot welding (FSpW) to join polyamide 6 and polyamide 66/carbon fibre laminate

Friction spot welding is an innovative technique developed and patented in 2005 by the research centre Helmholtz Zentrum Geesthacht. Advantages of the process include fast joining cycles, low operational costs and good mechanical performance. It was originally developed to weld lightweight metals and has been continuously improved to weld polymers. There are only a few studies on friction spot welding of thermoplastics, and the welding of polymeric composites by Friction spot welding (FSpW) is still unpublished. This study demonstrated the technical feasibility of welding a polyamide 6 (PA6) plate over a carbon fibre polyamide 66 laminate (CF-PA66) by FSpW. The thermal history, the surface finish, the microstructure of the weld region and the mechanical shear strength of PA6/CF-PA66 lap joints were investigated. The increase in the diameter of the clamping ring – originally designed for welding lightweight metals – led to the selection of welding parameters that result in high heat input, resulting in an increased welded area and lower notch left by the tool in the sample that improved the surface finish of the weld. This optimisation resulted in a PA6/CF-PA66 joint with lap shear strength of 35 MPa (2196 N), with fracture occurring mainly in the top plate of PA6.

Definition of welding parameters by cooling time in temperature range 800-500ºC

Cooling time in the temperature range 800 - 500°C has a great effect on the structures that arrise in the heat affected zone of welds steel. Data on optimal cooling time t8/5 for the certain steels can be found in the literature. The period of the cooling time t8/5, during the welding of the particular joints, in addition to the thickness and physical properties of welded steel, depends on shape of the weld, the welding process and welding parameters as well. In this work, the procedure for the selection of welding parameters for a butt joint welded to the microalloyed steel P 460 NL1 is presented. The microstructure in the heat affected zone and the results of measurement of their hardness are showed and analysed. It is concluded that the welding parameters selected with the help of cooling time t8/5 provide the satisfactory structure and hardness of welds.

Parametric optimization of seam welding of stainless steel (SS 304) sheets

Abstract In the present study, seam welding process parameters were optimized for joining 306 stainless steel plates. Welding pressure, welding speed and welding temperature combinations were carefully selected with the objective of producing a weld joint with maximum impact strength and hardness. Taguchi technique was applied for optimizing the selected welding parameters. The factors used in this study consisted of pressure, welding speed and welding temperature, each of which had three levels in the study. L27 orthogonal array and corresponding levels were selected according to the aforementioned factors and experimental tests were performed. Signal-to-noise (S/N) ratio was used to evaluate the experimental results. The results indicate that the welding speed has the greatest influence on impact strength, followed by welding pressure and temperature. Experiments have also been conducted to validate the optimized parameters.

A novel hybrid intelligent optimization model for twin wire tandem co-pool high-speed submerged arc welding of steel plate

In order to solve the welding formation defects of undercut and hump caused by the irrationality selection of parameters at a high welding speed more than 100cm/min in twin wire tandem co-pool submerged arc welding, a novel hybrid intelligent optimization model for twin wire tandem co-pool high speed submerged arc welding is proposed. This model combines local mean decomposition (LMD), energy entropy, back propagation neural network (BPNN) and particle swarm optimization algorithm (PSO). LMD is employed to decompose the collected welding current signal, excavate the underlying arc feature information related to the rationality of parameters and welding quality of welding seam formation appearance and sectional morphology. The energy entropy is used as the quantificational parameter to describe the rationality of parameters and welding quality. The relationship between the welding parameters and the energy entropy is established by BPNN, and the welding parameters are automatically obtained by the PSO. The application shows that the model is able to reliably achieve the optimization selection of welding parameters to guarantee welding quality.

Weld Quality Prediction Using Artificial Intelligence Technique

Decision-making process in manufacturing environment is increasingly difficult due to the rapid changes in design and demand of quality products. To make decision making process online, effective and efficient artificial intelligent tools like neural networks are being attempted. Usually, the desired welding parameters are determined using traditional methods like welder’s experiences, charts and handbooks (preferred values) which are simple and inexpensive. But this does not ensure that the selected welding parameters result in satisfactory welding and this method is not applicable to new welding process. To overcome this problem, various methods of obtaining the desired output variables through models to correlate input variables with output variables have been developed. Fractional factorial techniques, Mathematical modeling, curvilinear regression equations, linear regression equations, response surface methodology, finite element modeling, grey-based Taguchi method and sensitivity analysis were used to model SAW process. These methods are limited in application due to difficulties in modeling, time consuming and cumbersome. Due to the inadequacy and inefficiency of the mathematical models to explain the nonlinear properties existing between the input and output parameters of welding lead to the development of intelligent modeling techniques. Precise simulation and analysis of the process needs attention which helps to predict the wide variety of process parameters to set the factory floor in real time. The type of artificial intelligence capable of responding to changes in the automated manufacturing environment, and having the ability to capture vast manufacturing knowledge isAdaptive Neuro Fuzzy Inference System (ANFIS). It is becoming widely used in all aspects of manufacturing process to assist humans. Realizing that matter, ANFIS a state of the art artificial intelligent method, has the possibility to enhance the prediction of weld quality to find the best combination of independent variables which is welding current (I), speed (S) and welding voltage (V) as the input variables in order to achieve desired weld quality. Thus, the main objectives of this project is to develop ANFIS model to predict weld quality.

Welding Parameter Optimization of Surface Quality by Taguchi Method

An experimental study of GTAW was conducted to determine the optimization of weld parameters on the droplet formation in the surface quality of weld pools. These optimization investigations consisted of welding current, welding speed and feed rate. The strength and surface quality of weld pool were measured for each specimen after the welding parameter optimizations and the effect of these parameters on droplet formation were researched. To consider these quality characteristics together in the selection of welding parameters, the Orthogonal Array of Taguchi method is adopted to analyze the effect of each welding parameter on the weld pool quality, and then to determine the welding parameters with the optimal weld pool quality.

Prediction of Flux Cored Arc Welding (FCAW) Parameters and Bead Geometry in Downhill Position (3F)

The robot can perform Flux Cored Arc Welding (FCAW) at high productivity and consistency in quality. The quality of the welding depend on the selection of welding parameter and deposition geometry. These input has to be known before the start of production, generally the welding operator will obtain the information through experimental trial and error. This project planned to develop a tool that can advise the choice of welding parameter that produce quality weld bead with desired geometry. This research focused on the correlation of heat input on weld bead geometry and the range of welding parameter for fillet design welded in downhill direction (3F). From the correlation trend-line equations and welding parameter population boundary, the weld bead geometry and welding parameter for quality deposit are predicted. Consequently two calculators were developed to display the values digitally. The deviation of predicted bead geometry from actual welding is less than 1mm. Mean Absolute Deviation (MAD) is less than 0.4mm, accuracy is good. A wide range of welding parameters can be generated for quality welding at desired bead geometry.

Calorimetric analyses of the comprehensive heat flow for gas metal arc welding

Within this manuscript, the comprehensive heat flow, as well as the energy balance for gas-shielded arc welding processes based on experimental investigations is discussed. The main focus lies on the gas metal arc welding (GMAW) process which is further analysed. Different calorimetric measurement methods and results for the separate determination of the energy content of droplet and welding arc as well as energy input into the component are presented. Additionally, heat losses to the surrounding atmosphere and the cooling energy of the external cooling power source system are analysed. The mean droplet temperatures are within a range of T dr = 2,350 … 2,700 °C. The studies also show that a specific manipulation of the droplet temperature during the welding process is not possible and droplet temperature depends on several parameters. Increasing the wire feed speed, reducing the diameter of the filler material or increasing the stick out length result in an increase of the droplet temperature. The analyses allow to conclude that the welding arc is mainly responsible for the weld seam penetration and the droplet temperature only contributes in a minor manner. Preliminary experiments also show that the heat input into the component is highly influenced by the selection of welding parameters. Measurements confirm that it is possible to increase the efficiency of welding processes for example by reducing the wire feed speed, using carbon dioxide shielding gas or increasing the stick out length. On the contrary, increasing the current or voltage or reducing the shielding gas flow reduces the process efficiency. The difference between the lowest and highest achievable value of efficiency can be more than 15 % for one specific welding process.

Effect of welding parameters on microstructure and mechanical properties of AA6061-T6 butt welded joints by stationary shoulder friction stir welding

Stationary shoulder friction stir welding (SSFSW) butt welded joints were fabricated successfully for AA6061-T6 sheets with 5.0mm thickness. The welding experiments were performed using 750–1500rpm tool rotation speeds and 100–300mm/min welding speeds. The effects of welding parameters on microstructure and mechanical properties for the obtained welds were discussed and analyzed in detail. It is verified that the defect-free SSFSW welds with fine and smooth surface were obtained for all the selected welding parameters, and the weld transverse sections are obviously different from that of conventional FSW joint. The SSFSW nugget zone (NZ) has “bowl-like” shapes with fairly narrow thermal mechanically affected zone (TMAZ) and heat affected zone (HAZ) and the microstructures of weld region are rather symmetrical and homogeneous. The 750–1500rpm rotation speeds apparently increase the widths of NZ, TMAZ and HAZ, while the influences of 100–300mm/min welding speeds on their widths are weak. The softening regions with the average hardness equivalent 60% of the base metal are produced on both advancing side and retreating side. The tensile properties of AA6061-T6 SSFSW joints are almost unaffected by the 750–1500rpm rotation speeds for given 100mm/min, while the changing of welding speed from 100–300mm/min for given 1500rpm obviously increased the tensile strength of the joint and the maximum value for welding parameter 1500rpm and 300mm/min reached 77.3% of the base metal strength. The tensile fracture sites always locate in HAZ either on the advancing side or retreating side of the joints.

Morphological Characteristics and Mechanical Property of Continuous Drive Friction Welded Joints of Carbon Steel 45(GB)

The influence of friction pressure and time on morphological characteristics and mechanical property of the continuous drive friction welded joints of medium carbon steel 45(GB) was investigated in terms of the newly proposed two character factors, i.e. sticky length to diameter ratio α = length of welded zone / original diameter and scaling factor η = width of outer heat affected zone / width of center heat affected zone. The results show that, with the increase of friction pressure the sticky length to diameter ratio α increases firstly and then decreases, while the scaling factor η increases all along. However,by a friction pressure 60 MPa, the sticky length to diameter ratio α increases and the scaling factor η decreases continuously with the increasing friction time. When the integrative factor δ(δ =η/α) falls in a range 1.15- 1.31, the mechanical property of joints is good because the heat input is moderate, which therefore can be used as a criterion of selection of welding parameters for gaining good performance of the continuous drive friction welded joints of the steel 45(GB).

Prediction of weld shape for fiber laser keyhole welding based on finite element analysis

It is of great theoretical significance and engineering value to predict the weld shape for selecting welding parameters. A simplified and efficient three-dimensional (3D) heat conduction model was established to predict weld shape in fiber laser keyhole welding. An improved hybrid heat source model was proposed which consisted of a surface heat flux with a Gaussian distribution and a cylindrical heat source with damped peak value through the depth. The simulation results quite coincided with experimental ones, which indicated that the improved hybrid heat model can explain the energy absorption in keyhole more accurately. Both partially and fully penetrated weld shapes and sizes were predicted. The results showed that prediction errors of the sizes of weld cross-sections in partial-penetration welding were less than 8.9 %. While in full-penetrated welds, they were less than 8.8 % except for size of weld waist.

Aperfeiçoamento da técnica de Soldagem Pontual por Fricção (FSpW) para união de poliamida 6 e laminado de poliamida 66 com fibra de carbono

A Soldagem Pontual por Fricção ('Friction Spot Welding - FSpW') é uma técnica inovadora que foi desenvolvida e patenteada em 2005 pelo centro de pesquisa alemão Helmholtz Zentrum Geesthacht (HZG). A técnica apresenta ciclos rápidos, baixo custo operacional e gera soldas com alto desempenho mecânico. Foi inicialmente projetada para a soldagem de ligas metálicas leves. A soldagem de polímeros é alvo de pesquisas recentes e a soldagem de compósitos poliméricos por FSpW ainda é inédita. Este estudo demonstrou a viabilidade técnica da soldagem de chapa de poliamida 6 (PA6) e laminado de poliamida 66 e fibra de carbono (CF-PA66) por FSpW. O histórico térmico, o acabamento superficial, a microestrutura da região da solda e a resistência mecânica ao cisalhamento de juntas sobrepostas PA6/CF-PA66 foram investigados. O aumento do tamanho do anel de fixação da ferramenta original, projetada para a soldagem de metais, possibilitou a seleção de parâmetros de soldagem que resultaram em grande aporte térmico, resultando no aumento da área soldada, num menor entalhe (inscrição) deixado pela ferramenta na amostra, produzindo melhoria no acabamento superficial da solda. Essa otimização resultou em uma junta PA6/CF-PA66 com resistência ao cisalhamento de 35 MPa (2196 N), com fratura predominante na placa superior de PA6.

Properties and weldability of plasticized polylactic acid films

ABSTRACTThe objectives of the presented work were to investigate films based on polylactic acid (PLA) and polyethylene glycol (PEG) in order to improve ductility and weldability of PLA films. The effect of plasticizer amount on the thermal, rheological, and mechanical properties of PLA plasticized films was investigated. The PEG content does affect the glass transition and the cold crystallization temperature of PLA in blends, while the melting temperature was not affected by the addition of PEG. The complex viscosity of the neat PLA granules and of plasticized films showed strong temperature and angular velocity dependence. The Young's modulus and tensile strength of plasticized films were improved with increasing plasticizer concentration, while the elongation at break stays rather constant. Plasticized PLA films were furthermore heat welded. These investigations showed that plasticized PLA films can be welded by heat welding. The obtained weld strength is strongly depending on the PEG amount as well as on selected welding parameters. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40394.

A study of cold metal transfer clads in nickel-base INCONEL 718 superalloy

A study of microstructural and geometrical characteristics of cold metal transfer (CMT) clads in nickel-base INCONEL 718 superalloy was carried out. The CMT process was demonstrated to be suitable for low-dilution cladding of INCONEL 718 superalloy, with the ability to produce defect-free clads, and has a great potential to be used as a repair method for the alloy. Microstructural study revealed that the clads were free from porosity and cracking, and complete bonding of the clads with the substrate was achieved in all weldments. Results from statistical analysis by using 3-level full factorial design showed the relationship between the selected welding parameters and the geometrical characteristics of the clads. Regression models were developed for predicting weld characteristics. Analysis of variance (ANOVA) was used to test the adequacy of the regression models, which showed that the models are useful for optimizing the welding parameters. Also, the wire feed speed appeared to be linearly related with heat input based on the parameters used during the synergic CMT welding, which consequently influenced the shape and size of the weld beads and the extent of dilution of the weld metal with the substrate when other parameters were kept constant. Additionally, the ease of adding successive weld passes for material build-up depends significantly on the contact angle between the weld bead and the substrate. The result showed that the closer the contact angle is to 90°, the more difficult it is to add successive passes to existing clads. A contact angle greater than 115° appears to be more convenient for adding successive passes. The outcome of this work showed that the relatively new CMT process, with the choice of suitable welding parameters, is useful for repair build-up of affected areas of worn-out and service-damaged components of gas turbines and other high-temperature equipment that are manufactured from nickel-base superalloys.

Power factor model for selection of welding parameters in CW laser welding

Abstract Laser welding offers enormous flexibility in terms of delivered energy. It does however, require a vast amount of parameters and phenomena to be monitored in order to control the process and to ensure high quality processing. In laser welding the same depth of penetration can be achieved using different combinations of parameters, such as laser power, travel speed. The problem is further complicated by the effect of beam diameter, which may vary significantly between different laser systems. In this work an empirical model, which enables achievement of a particular depth of penetration independent of the beam diameter is presented. First, the user selects a weld shape which meets a certain quality requirements and depth of penetration that have to be accommodated and then the model will specify how to achieve this weld using a particular laser system with a particular beam diameter.

Orthogonal Experiment of Resistance Microwelding of Insulated Copper Wire and Phosphor Bronze Sheet

The selection of welding parameter has an important effect on weld quality. In this paper, an orthogonal experiment method was used to optimize the resistance microwelding (RMW) parameters for the connection of insulated copper wire and phosphor bronze sheet. An orthogonal array with three factors (welding current, weld time and electrode force) and five levels was used. Joint breaking force (JBF) and surface appearance were selected as the evaluation criterion of the weld quality. The results show that welding current was the most influencing parameter on joint strength, while the electrode force had the most significant effect on the surface appearance. The orthogonal method was proved to be an effective method to obtain the optimum conditions for RMW of insulated copper wire.

Effects of Welding Parameters Onto Keyhole Geometry for Partial Penetration Laser Welding

The material and parameters like welding speed and laser beam parameters define the geometry of the keyhole. The keyhole geometry affects the weld geometry, such as width and depth, and in some cases it should be considered when selecting welding parameters. In-situ X-ray videography makes it possible to obtain time-and space resolved information about the keyhole geometry during the welding process. This paper describes the partial penetration laser welding experiments and shows the effects of a welding speed and a focal point position change onto some geometry values of the keyhole. Two different joint types were used, bead on plate to simulate a very good machined joint preparation and laser cut I-butt joint.

Experimental Determination of Cooling Rate and its Effect on Microhardness in Submerged Arc Welding of Mild Steel Plate (Grade c-25 as per IS 1570)

An experiment based thermal analysis has been performed to obtain the thermal histories, which can be applied to determine cooling rate of weldment. During fusion welding process it is possible to determine temperature at any point by using thermocouple and from such data it is possible to draw thermal histories for any point of interest, such thermal histories can be utilized to determine cooling rate. The temperature distribution and cooling rate during the welding process have significant effect on the mechanical and metallurgical properties of a weldment. The changes in microstructure, grain growth and hardness in a weldment are very dependent on the temperature distribution and cooling rate. These studies are utilized to investigate the micro-structure and microhardness of the heat affected zone (HAZ) and weldment. In present work, the influence of heat input and cooling rate on microhardness has been investigated. Full factorial design is used to conduct the experiment with three factors and two levels. Eight combinations and two set of heat input are designed with different combinations of SAW welding parameters. Temperature distribution curves and cooling rate have been drawn. The effect of selected welding parameters (Wire feed rate, Open circuit Voltage and welding Speed) on the microhardness have been investigated.

Procedure for welding a supporting plate of a tracked vehicle: choice of parameters and calculation of welding cost

An approach for the development of a welding procedure for bed plates is presented. The method of selection of welding parameters as well as parent materials and welding consumables are discussed. Two ways of calculation of financial outlays on the manufacture of welded joints are given.

Optimization of weld bead geometry in laser welding with filler wire process using Taguchi’s approach

In the present work, laser welding with filler wire was successfully applied to joining a new-type Al–Mg alloy. Welding parameters of laser power, welding speed and wire feed rate were carefully selected with the objective of producing a weld joint with the minimum weld bead width and the fusion zone area. Taguchi approach was used as a statistical design of experimental technique for optimizing the selected welding parameters. From the experimental results, it is found that the effect of welding parameters on the welding quality decreased in the order of welding speed, wire feed rate, and laser power. The optimal combination of welding parameters is the laser power of 2.4kW, welding speed of 3m/min and the wire feed rate of 2m/min. Verification experiments have also been conducted to validate the optimized parameters.