scholarly journals Dissimilar Non-Ferrous Metal Welding: An Insight on Experimental and Numerical Analysis

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1486
Author(s):  
Jeyaganesh Devaraj ◽  
Aiman Ziout ◽  
Jaber E. Abu Qudeiri

In recent years Gas Metal Arc Welding (GMAW) technology has expanded its functionalities in various areas which have further motivated its usage in several emerging manufacturing industries. There are several issues and challenges associated with this technology, especially in dissimilar metal welding (DMW). One of the predominant challenges is selecting appropriate welding parameters which influence the efficiency of this technology. To explore several modern advancements in this expertise, this paper has done an exclusive survey on various standards of GMAW and its variants for selecting suitable parameters for welding dissimilar nonferrous metals. This review summarizes various experimental and numerical results along with related illustrations to highlight the feasibility of welding dissimilar nonferrous metals using traditional GMAW and investigations on advanced GMAW processes such as cold metal transfer (CMT) and pulsed GMAW (P-GMAW). Simulation and modeling of nonferrous DMW have identified several research gaps and modeling problems. Researchers and manufacturers can use this review as a guideline to choose appropriate welding parameters to implement GMAW and its variants for non-ferrous dissimilar welding. It found that by controlling the heat input and effective post-heat treatments, adequate joint properties can be achieved. Automated large -scale manufacturing will widen the utilization scope of GMAW and avoid some costly methods such as laser welding, ultrasonic welding, and friction stir welding etc.

2019 ◽  
Vol 28 (1) ◽  
pp. 135-145 ◽  
Author(s):  
Addanki Ramaswamy ◽  
Sudersanan Malarvizhi ◽  
Visvalingam Balasubramanian

AbstractAluminium alloys of 6xxx series are widely used in the fabrication of light weight structures especially, where high strength to weight ratio and excellent weld-ability characteristics are desirable. Gas metal arc welding (GMAW) is the most predominantly used welding process in many industries due to the ease of automation. In this investigation, an attempt has been made to identify the best variant of GMAW process to overcome the problems like alloy segregation, precipitate dissolution and heat affected zone (HAZ) softening. Thin sheets of AA6061-T6 alloy were welded by cold metal transfer (CMT) and Pulsed CMT (PCMT). Among the two joints, the joint made by PCMT technique exhibited superior tensile properties due to the mechanical stirring action in the weld pool caused by forward and rearward movement of the wire along with the controllable diffusion rate at the interface caused by shorter solidification time. However, softening still exists in the welded joints. Further to increase the joint efficiency and to minimize HAZ softening, the joints were subjected to post weld heat treatment (PWHT). Approximately 10% improvement in the tensile properties had been observed in the PWHT joints due to the nucleation of strengthening precipitates in the weld metal and HAZ.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Jae Won Kim ◽  
Jae-Deuk Kim ◽  
Jooyoung Cheon ◽  
Changwook Ji

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κIII structure with β´ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κIII structure in between.


2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Nilay Çömez ◽  
Hülya Durmuş

Cold metal transfer (CMT) welding provides many advantages for welding of dissimilar materials and thin sheets with its superior heat input control mechanism. In this study, AA6061 and AA7075 aluminum alloys were joined with CMT welding. The effect of welding parameters on hardness, tensile strength, and corrosion rate was investigated. The Tafel extrapolation method was carried out to determine the corrosion rates of AA6061 and AA7075 base metals and AA6061–AA7075 joints. Increasing heat input was found to be detrimental for both mechanical properties and corrosion resistance. The outcomes showed that CMT welding produces adequate joints of AA6061–AA7075 in terms of mechanical properties and corrosion resistance, favorably with welding parameters that provide low heat input.


Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2671 ◽  
Author(s):  
Maximilian Gierth ◽  
Philipp Henckell ◽  
Yarop Ali ◽  
Jonas Scholl ◽  
Jean Pierre Bergmann

Large-scale aluminum parts are used in aerospace and automotive industries, due to excellent strength, light weight, and the good corrosion resistance of the material. Additive manufacturing processes enable both cost and time savings in the context of component manufacturing. Thereby, wire arc additive manufacturing (WAAM) is particularly suitable for the production of large volume parts due to deposition rates in the range of kilograms per hour. Challenges during the manufacturing process of aluminum alloys, such as porosity or poor mechanical properties, can be overcome by using arc technologies with adaptable energy input. In this study, WAAM of AlMg5Mn alloy was systematically investigated by using the gas metal arc welding (GMAW) process. Herein, correlations between the energy input and the resulting temperature–time-regimes show the effect on resulting microstructure, weld seam irregularities and the mechanical properties of additively manufactured aluminum parts. Therefore, multilayer walls were built layer wise using the cold metal transfer (CMT) process including conventional CMT, CMT advanced and CMT pulse advanced arc modes. These processing strategies were analyzed by means of energy input, whereby the geometrical features of the layers could be controlled as well as the porosity to area portion to below 1% in the WAAM parts. Furthermore, the investigations show the that mechanical properties like tensile strength and material hardness can be adapted throughout the energy input per unit length significantly.


Author(s):  
Iikka Virkkunen ◽  
Mikko Peltonen ◽  
Henrik Sirén ◽  
Pekka Nevasmaa ◽  
Caitlin Huotilainen ◽  
...  

Abstract Aging management of the existing fleet of nuclear power plants is becoming an increasingly important topic, especially as many units are approaching their design lifetimes or are entering long-term operation. As these plants continue to age, there is an increased probability for the need of repairs due to extended exposure to a harsh environment. It is paramount that qualified and validated solutions are readily available. A repair method for a postulated through cladding crack into the low alloy steel of a nuclear power plant’s reactor pressure vessel has been investigated in this study. This paper is part of larger study that evaluates the current possibilities of such repair welds. The present paper documents the weld-trials and method selection. A parallel paper describes numerical simulations and optimization of weld parameters. The presented weld-trial represents a case where a postulated crack has been excavated and repaired using a nickel base Alloy 52M filler metal by gas metal arc welding-cold metal transfer with a robotic arm. A SA235 structural steel has been used as a base material in this weld-trial. No pre-heating or post-weld heat treatment will be applied, as it would be nearly impossible to apply these treatments in a reactor pressure vessel repair situation. While Alloy 52M presents good material properties, in terms of resistance to environmentally assisted degradation mechanisms, such as primary water stress corrosion cracking, it is notoriously difficult to weld. Some difficulties and challenges during welding include a sluggish weld puddle, formation of titanium and/or aluminium oxides and its susceptibility to lack of fusion defects and weld metal cracking, such as ductility dip cracking and solidification cracking. Moreover, gas metal arc welding-cold metal transfer is not traditionally used in the nuclear industry. Nonetheless, it presents some interesting advantages, specifically concerning heat input requirements and automation possibilities, as compared to traditional welding methods. The mechanical properties, in terms of indentation hardness, and microstructure of a weld-trial sample have been evaluated in this study. The fusion boundary and heat affected zone were the main areas of focus when evaluating the mechanical and microstructural properties. Detailed microstructural characterization using electron backscatter diffraction and nanoindentation were performed across the weld interface. Based on these results, the gas metal arc welding cold metal transfer is seen as a potential high-quality weld method for reactor pressure vessel repair cases.


Author(s):  
Sirakizhanthanallur Tamilselvan Selvamani

The versatile aluminium alloys and steel are being used in automotive engines (exhaust systems), pressure vessels (flanges), turbine rotors, boilers (bonnet) and in many applications. The collective effect of these two metals created a revolution and are being utilized in most of the sectors wherein joining of these two dissimilar materials are always a major challenge faced by the manufacturers. Initially, the rivets were widely used for joining dissimilar materials owing to easy installation and flexibility, but the joint interlock fails and sudden ruptures occurred when exposed to higher load. Hence, numerous welding processes like metal inert gas welding, friction stir welding, friction stir spot welding, advanced laser welding, advanced cold metal transfer welding and hybrid welding techniques have been introduced in order to conquer the above problem because of residual stresses, cracks, distortion, and undercuts. Moreover, an appropriate standardization with controlled process inputs is still an uncertainty in joining the dissimilar materials. Hence, a detailed review on joining the dissimilar metals based on aluminium alloy and steel by various welding processes and influence of their parameters on the properties have been summarized in detail which would be a reference for manufacturing industries in the coming decades.


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