Papers by Keyword: Gas Metal Arc Welding

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Authors: Kaewkuekool Sittichai, Laemlaksakul Vanchai, Rodsung Detnarong
Abstract: The objective of this research was to study the effect of filler metal, which was influenced to mechanical properties welding of Austenitic Stainless Steel AISI 304 on gas metal arc welding (GMAW) process. Factorial design was applied for this study. Factors studied were consisted of filler metal, electric current, and speed of welding at each factor was set at three levels. Results revealed that interaction effect between electric current, and speed was affected to ultimate tensile strength and elongation significantly different at level of .01 and .05, respectively. Finally, main effect of speed factors was affected to yield point significantly different at the level of .05.
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Authors: Reenal Ritesh Chand, Ill Soo Kim, Ji Hye Lee, Jong Pyo Lee, Ji Yeon Shim, Young Su Kim
Abstract: In robotic GMA (Gas Metal Arc) welding process, heat and mass inputs are coupled and transferred by the weld arc and molten base material to the weld pool. The amount and distribution of the input energy are basically controlled by the obvious and careful choices of welding process parameters in order to accomplish the optimal bead geometry and the desired mechanical properties of the quality weldment. To make effective use of automated and robotic GMA welding, it is imperative to predict online faults for bead geometry and welding quality with respect to welding parameters, applicable to all welding positions and covering a wide range of material thickness. To successfully accomplish this objective, two sets of experiment were performed with different welding parameters; the welded samples from SM 490A steel flats adopting the bead-on-plate technique were employed in the experiment. The experimental results of current and voltage waveforms were used to predict the magnitude of bead geometry and welding quality, and to establish the relationships between weld process parameters and online welding faults. MD (Mahalanobis Distance) technique is employed for investigating and modeling of GMA welding process and significance test techniques were applied for the interpretation of the experimental data. Statistical models developed from experimental results which can be used to control the welding process parameters in order to achieve the desired bead geometry based on weld quality criteria.
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Authors: Zhen Zhou Wang, Yang Yu, Shu Jun Chen, Yu Ming Zhang
Abstract: Controlled metal transfer in gas metal arc welding (GMAW) and its modifications including the double-electrode GMAW implies controllable heat and mass inputs and better assured weld quality. To understand, analyze, and control the metal transfer process, the droplet should be monitored in real time. Due to the fast development and transfer of the droplet, the monitoring speed is a key. A tracking method that takes advantage of results from previous images to speed the processing is advantageous. In this paper, Kalman Filter tracking and Least Square Match tracking algorithms are developed to track a droplet in the innovative double-electrode GMAW after its original position is identified. Experimental results showed that the Kalman Filtering algorithm is not suitable for this application due to the limited life span of each droplet. Instead, the Least Square Match algorithm is effective in tracking a droplet if a universal droplet template can be found and defined. However, there are no universal templates suitable for all the droplets. Hence, a real time template updating and LSM tracking method is proposed to track the droplet effectively. Experimental results verified its tracking accuracy.
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Authors: Mongkol Chaisri, Prachya Peasura
Abstract: The research was study the effect of gas metal arc welding process parameters on mechanical property. The specimen was carbon steel ASTM A285 grade A which thickness of 6 mm. The experiments with full factorial design. The factors used in this study are shielding gas and voltage. The welded specimens were tested by tensile strength testing and hardness testing according to ASME boiler and pressure vessel code section IX 2007. The result showed that both of shielding gas and voltage had interaction on tensile strength and hardness at 95% confidential (P value < 0.05). Factors affecting the tensile strength are the most carbon dioxide and 27 voltage were tensile strength 213.43 MPa. And hardness maximum of 170.60 HV can be used carbon dioxide and 24 voltage. This research can be used as data in the following appropriate parameters to gas metal arc welding process.
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Authors: Pakpoom Jittavisuttiwong, Bovornchok Poopat
Abstract: Helium is widely used as mixing with argon for a shielding gas in GMAW process of Aluminum in order to improve weld quality and increase heat transfer to the weld pool. It has been known that helium could affect metal transfer behavior; however, its behavior has not been well understood. In this study, an analysis of the metal transfer behavior in the GMAW of aluminum was studied. The main objective is to study the effect of Helium on metal transfer in two main regions, short circuit (low welding current region) and spray transfer (high current region). The composition of 5 types of shielding gases were pure argon, 75%Ar + 25%He, 50%Ar + 50%He, 25%Ar + 75%He and pure helium. The welding parameters were fixed at 90A/17.0V, 100A/18.2V, 140A/24.6V and 180A/27.6V. Aluminum plates were welded bead-on-plate in a flat position. The metal transfer behavior was analyzed by using acoustic signals and arc voltage signals. For the result, at low welding current of 90A and 100A with pure argon, short-circuit transfer mode was observed. Adding helium in gas mixture gave no effect in metal transfer mode in low welding current regions but the metal transfer rate was slightly increased. At high welding currents of 140A and 180A with pure argon, spray transfer mode was observed and when increasing helium in gas mixture resulted in changing from spray transfer to combined mode of spray-globular. In these high welding currents, adding helium in gas mixture resulted in decreasing the metal transfer rate since helium gas tended to promote globular metal transfer. Acoustic signal and arc voltage signal can be used effectively in determining modes of metal transfer.
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Authors: Jarnail Singh, Hazoor Singh
Abstract: In present study, an attempt was made to reduce the erosion rate of the Pulverized coal burner nozzle material. For better resistant to erosion, material was hardfaced by Gas Metal Arc Welding (GMAW) by using solid wire electrode and flux cored wire electrode under same welding conditions. The substrate steel hardfaced with flux cored wire electrode resulted in high microhardness as compare to solid wire electrode. The erosion study was conducted, using an air jet erosion test rig at a particle velocity of 50 m/s. Ductile erosion behavior is observed in the case when the substrate steels is hardfaced with solid wire whereas brittle erosion behavior is observed when the substrate steels is hardfaced with flux cored wire. At a low angle of impingement, the abrasive type cutting is the dominating factor for material removal, and at a higher angle of impingement, impact-type as well as abrasive-type cutting actions play critical roles. Plastic deformation characterized by pitting and cutting action was also observed. Scanning electron microscopy (SEM) technique was used to analyze the eroded surface. It was concluded that damaged surfaces of Pulverized coal burner nozzle material can be successfully hardfaced and improvement in erosion resistance was observed.
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Authors: Shu Jun Chen, Chang Hui Liu, Yang Yu, Shao Jun Bai
Abstract: This study proposed preset pulsed magnetic field acting on process of the short circuiting transfer. It is a controlled horizontal magnetic field which attached at the very beginning of contact between the wire and the weld pool during welding. It was found that there exists optimum conditions of magnetic field with which preset pulsed magnetic field could accelerate the rupture of the liquid bridge and reduce the peak value of welding current in the period of short circuiting transfer. This lead to energy accumulation lowered at the last phase of the short circuiting transfer and spatter loss reduced resulting from explosive short circuit rupture, in the meantime, it could improve the regularity and stability of the short circuiting transfer as well as the weld shaping quality.
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Authors: Winarto, Muhammad Anis, Teguh Puji Hertanto
Abstract: Joining of dissimilar metals is to compose different properties of metals in order to minimize material costs and at the same time to maximize the performance of the equipment and machinery. There are a lot of methods of joining of dissimilar metals. However, the fusion welding is mostly used in a wide range of industries. This research is carried out for the process of dissimilar welding between carbon steel plates of ASTM A516-70 and austenitic stainless steel plates ASTM A214-316L by using gas metal arc welding (GMAW). Welding design used is a V-groove by using the buttering process and without buttering (non-buttering) process. Types of filler metals used are ER309L and ER316L-Si. The weldment is then tested by using destructive test (DT) and non-destructive test (NDT). Weldment is also characterized by using X-Ray Diffraction (XRD). The results show that the mechanical properties of weldment with buttering process are better compared with the weldment with a non-buttering process. The macro and microstructure of weldment with buttering process revealed finer grained and homogeneous structures compared with the one by using a non-buttering process. Moreover, welds characterization by using XRD show that the precipitation of chromium carbide on HAZ of weldment with buttering process is lower than that of weldment with a non-buttering process.
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Authors: Il Soo Kim, Ji Hye Lee, Javad Malekani, Prasad K.D.V. Yarlagadda
Abstract: Nowadays, demand for automated Gas metal arc welding (GMAW) is growing and consequently need for intelligent systems is increased to ensure the accuracy of the procedure. To date, welding pool geometry has been the most used factor in quality assessment of intelligent welding systems. But, it has recently been found that Mahalanobis Distance (MD) not only can be used for this purpose but also is more efficient. In the present paper, Artificial Neural Networks (ANN) has been used for prediction of MD parameter. However, advantages and disadvantages of other methods have been discussed. The Levenberg–Marquardt algorithm was found to be the most effective algorithm for GMAW process. It is known that the number of neurons plays an important role in optimal network design. In this work, using trial and error method, it has been found that 30 is the optimal number of neurons. The model has been investigated with different number of layers in Multilayer Perceptron (MLP) architecture and has been shown that for the aim of this work the optimal result is obtained when using MLP with one layer. Robustness of the system has been evaluated by adding noise into the input data and studying the effect of the noise in prediction capability of the network. The experiments for this study were conducted in an automated GMAW setup that was integrated with data acquisition system and prepared in a laboratory for welding of steel plate with 12 mm in thickness. The accuracy of the network was evaluated by Root Mean Squared (RMS) error between the measured and the estimated values. The low error value (about 0.008) reflects the good accuracy of the model. Also the comparison of the predicted results by ANN and the test data set showed very good agreement that reveals the predictive power of the model. Therefore, the ANN model offered in here for GMA welding process can be used effectively for prediction goals.
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Authors: N.I.S. Hussein, Mohamad Nizam Ayof, Tan Huay Kean
Abstract: Dissimilar metal welding is widely applied to meet the rquirement of transition in mechanical properties and/or difference in working conditions. For instance, even though AISI 304 and AISI 316L are both belong to austenitic stainless steels, but they are applied in different working environment. AISI 304 is used at high temperature applications, whereas AISI 316L is used at low temperature. Repair welding is able to return a part back to its normal service life if weld failure happened due to service deterioration or defects during fabrication stage. However, repetitive heat input due to repair welding will cause changes in welded structure and properties. In this article, the effect of repetitive repair welding of dissimilar austenitic stainless steel pipes to the microhardness, tensile strength, microstructure and quality of the weldment has been reviewed.
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