scholarly journals The Effect of Groove Shape on Molten Metal Flow Behaviour in Gas Metal Arc Welding

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7444
Author(s):  
Amin Ebrahimi ◽  
Aravind Babu ◽  
Chris R. Kleijn ◽  
Marcel J. M. Hermans ◽  
Ian M. Richardson

One of the challenges for development, qualification and optimisation of arc welding processes lies in characterising the complex melt-pool behaviour which exhibits highly non-linear responses to variations of process parameters. The present work presents a computational model to describe the melt-pool behaviour in root-pass gas metal arc welding (GMAW). Three-dimensional numerical simulations have been performed using an enhanced physics-based computational model to unravel the effect of groove shape on complex unsteady heat and fluid flow in GMAW. The influence of surface deformations on the magnitude and distribution of the heat input and the forces applied to the molten material were taken into account. Utilising this model, the complex thermal and fluid flow fields in melt pools were visualised and described for different groove shapes. Additionally, experiments were performed to validate the numerical predictions and the robustness of the present computational model is demonstrated. The model can be used to explore the physical effects of governing fluid flow and melt-pool stability during gas metal arc root welding.

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.


2012 ◽  
Vol 56 (9-10) ◽  
pp. 35-40 ◽  
Author(s):  
Uwe Reisgen ◽  
Marion Beckers ◽  
Guido Buchholz ◽  
Konrad Willms

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