Prediction of Weld Bead Dilution in GMAW Process Using Fuzzy Logic

2011 ◽  
Vol 110-116 ◽  
pp. 3171-3175 ◽  
Author(s):  
Masood Aghakhani ◽  
Maziar Mahdipour Jalilian ◽  
Alimohammad Karami

Gas metal arc welding is one of the most important arc welding processes used in manufacturing and repair. In this process selecting appropriate values for process variables is essential in order to decide upon metal transfer and subsequently control the heat input into the workpiece from which reliable predictions could be made about the metallurgical, mechanical properties and performance of the welded joints. In this paper, the welding dilution in gas metal arc welding of ST37 steel has been predicted by fuzzy logic. A five level five factor rotatable central composite design was used to collect the welding data and the weld dilution was modeled as a function of wire feed rate, welding voltage, nozzle-to-plate distance, welding speed and gas flow rate.

2011 ◽  
Vol 110-116 ◽  
pp. 2963-2968 ◽  
Author(s):  
Masood Aghakhani ◽  
Ehsan Mehrdad ◽  
Ehsan Hayati ◽  
Maziar Mahdipour Jalilian ◽  
Arash Karbasian

Gas metal arc welding is a fusion welding process which has got wide applications in industry. In order to obtain a good quality weld, it is therefore, necessary to control the input welding parameters. In other words proper selection of input welding parameters in this process contribute to weld productivity. One of the important welding output parameters in this process is weld dilution affecting the quality and productivity of weldment. In this research paper using Taguchi method of design of experiments a mathematical model was developed using parameters such as, wire feed rate (W), welding voltage (V), nozzle-to-plate distance (N), welding speed (S) and gas flow rate (G) on weld dilution. After collecting data, signal-to-noise ratios (S/N) were calculated and used in order to obtain the optimum levels for every input parameter. Subsequently, using analysis of variance the significant coefficients for each input factor on the weld dilution were determined and validated. Finally a mathematical model based on regression analysis for predicting the weld dilution was obtained. Results show that wire feed rate (W),arc voltage (V) have increasing effect while Nozzle-to-plate distance (N) and welding speed (S) have decreasing effect on the dilution whereas gas Flow rate alone has almost no effect on dilution but its interaction with other parameters makes it quite significant in increasing the weld dilution


Author(s):  
Rudreshi Addamani ◽  
Ravindra Holalu Venkatadas ◽  
Ugrasen Gonchikar ◽  
Y. D. Chethan

The Pulsed Gas Metal Arc Welding (P-GMAW) process is used in high-technology industrial applications and it is one of the most significant arc welding processes. The quality, productivity and cost of welding will be affected by the P-GMAW welding input process parameters and are considered to the most important factors. It is necessary to determine the input and output relationship of the welding processes in order to understand and control the P-GMAW welding process parameters. P-GMAW is widely used process, especially in thin sheet metal industries. It offers an improvement in quality and productivity over regular Gas Metal Arc Welding (GMAW). The process enables stable spray transfer with low mean current and low net heat input. This paper describes the estimation and comparison of welding process parameters viz., current, gas flow rate and wire feed rate on ultimate tensile strength, yield strength, percentage of elongation and hardness. Experiments have been performed based on Taguchi’s L27 standard orthogonal array. Estimation of welding performances have been carried out using sophisticated mathematical models viz., MRA and GMDH, and, compared. The GMDH algorithm is designed to learn the process by training the algorithm with the experimental data. Three different criterion functions, viz., regularity, unbiased and combined criterions were considered for estimation in GMDH. Different GMDH models can be obtained by varying the percentage of data in the training set and the best model can be selected from these, viz., 50%, 62.5% and 75%. Estimation and comparison of welding performances were carried out using MRA and GMDH techniques.


Author(s):  
Jaber Jamal ◽  
Basil Darras ◽  
Hossam Kishawy

The concept of “sustainability” has recently risen to take the old concept of going “green” further. This article presents general methodologies for sustainability assessments. These were then adapted to measure and assess the sustainability of welding processes through building a complete framework, to determine the best welding process for a particular application. To apply this methodology, data about the welding processes would be collected and segregated into four categories: environmental impact, economic impact, social impact, and physical performance. The performance of each category would then be aggregated into a single sustainability score. To demonstrate the capability of this methodology, case studies of three different welding processes were performed. Friction stir welding obtained the highest overall sustainability score compared to gas tungsten arc welding and gas metal arc welding.


Author(s):  
A Mathieu ◽  
I Tkachenko ◽  
JM Jouvard ◽  
I Tomashchuk

The present work covers the topic of strains and stresses prediction in case of welded steel structures. Steel sheets of 20 mm thickness made in UR™2507Cu are welded using a laser and gas metal arc welding processes combination. The focused laser beam leads the arc in a Y-shape chamfer geometry. Both sources are 20 mm apart from each other in order to avoid any synergic effect with each other. In order to predict residual strain, a 3D unsteady numerical simulation has been developed in COMSOL finite element software. A volume heat source has been identified based on the temperature measurements made by 10 K-type thermocouples, implanted inside the workpiece. The 50 mm deep holes are drilled in the workpiece using dye-sinking Electrical Discharge Machining (EDM) machine. Before the implantation in the hole, each thermocouple is surrounded by Inconel sheathing. Hot junctions of the thermocouples are positioned in a way to feel two advancing molten pools. The equivalent heat source is composed of three sources. First one is a Goldak source that represents the molten pool induced by gas metal arc welding. The second one is a cylinder with an elliptic cross-section that represents the focused laser beam penetrating into the workpiece. The third one is a surface Gaussian source that represents energy radiated by arc and blocked by workpiece surface. Concerning mechanical simulation, an elasto-plastic behavior with isotropic hardening is implemented. A weak coupling is established between equations governing heat transfer and mechanics thanks to the temperature dependent coefficient of linear expansion. This numerical simulation made with some simplifying assumptions predicts an angular distortion and a longitudinal shrinkage of the welded structure. The numerical results are consistent with the displacements measured by digital image correlation method.


2012 ◽  
Vol 67 (1-4) ◽  
pp. 655-674 ◽  
Author(s):  
P. Kah ◽  
R. Suoranta ◽  
J. Martikainen

1998 ◽  
Vol 120 (3) ◽  
pp. 600-608 ◽  
Author(s):  
S. B. Zhang ◽  
Y. M. Zhang ◽  
R. Kovacevic

A novel seam tracking technology based on high frequency ultrasound is developed in order to achieve high accuracy in weld seam identification. The transmission efficiency of the ultrasound is critical for obtaining a sufficient echo amplitude. Since the transmission efficiency is determined by the difference in impedance between the piezoelectric ceramic and air, match layers are designed to optimize the transmission efficiency by matching impedance. Since the air impedance depends on the density and velocity of the ultrasound, which both depend on the temperature, the optimization has been done for a wide bandwidth. Also, the receiving circuit is designed so that its resonance frequency matches the frequency of the ultrasound. As a result, the sensitivity of the noncontact ultrasonic sensor is improved 80-fold. By properly designing the focal length of the transducer, a high resolution ultrasound beam, 0.5 mm in diameter, is achieved. Based on the proposed sensing technology, a noncontact seam tracking system has been developed. Applications of the developed system in gas tungsten arc welding (GTAW) and CO2 gas metal arc welding (GMAW) processes show that a tracking accuracy of 0.5 mm is guaranteed despite the arc light, spatter, high temperature, joint configuration, small gap, etc.


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