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Selection of suitable parameter range is essential in joining dissimilar combinations joints when more than one number of influencing parameters are present in giving desired output. This paper dis...

Gas metal arc welding process offers higher productivity and good quality weldment as compared to other welding process. The changes in welding process parameters affect the weld bead shape, hardne...

In this paper, a two-directional automated machine with a controller for flat gas metal arc welding is developed for welding along any complex shape. Consistent and uniform weld bead deposition can...

From last decade, Friction Stir Welding (FSW) process finds increasing applications in industry as the process is environment-friendly and offers inherent advantages in mechanical and metallurgical...

Tungsten inert gas welding (TIG) is a widely used fusion welding process to produce a high quality of weld joint for the ferrous and nonferrous alloy with an esthetic weld bead. The limitation of t...

The TIG process with hot-wire addition is described as a highly productive process in comparison with conventional TIG process with cold-wire and achieves large deposition rates and low dil...

In order to produce welds that comply with the geometric specifications of a project, it is vital to properly control the weld pool. The ‘Plasma-MIG’ process using concentric arcs has been ...

© 2016 Institute of Materials, Minerals and Mining. The paper aims to characterise the strain concentration of welded junctions subjected to elastic loads using digital image correlation (DIC). When measuring such small strains and heterogeneous strains fields with DIC, a compromise between noise and accuracy arises where a suitable choice of the image processing settings becomes crucial to obtain accurate results. An extensive study of the influence of the different processing parameters was carried out to ensure the best trade-off between accuracy and noise. A practical application was later performed with the found optimal settings; welded specimens were subjected to uniaxial and biaxial loads to assess possible influence of the strain state on the strain concentration. Results show a great variability of the strain concentration along the weld bead base, evidencing a significant influence of local geometrical characteristics. On the other hand, the strain state influence was found to be moderate, or almost inexistent for lower strain concentrations. peerreview_statement: The publishing and review policy for this title is described in its Aims & Scope. aims_and_scope_url: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=ystw20 ispartof: Science and Technology of Welding and Joining vol:21 issue:8 pages:670-679 status: published

TIG welding has high levels of stability and permits more refined control than the majority of other arc welding processes. However, it is well known that small changes in the chemical composition of the base metal and arc operating region can have a pronounced effect on the resulting weld bead shape, which reduces the ability to control and predict the process. Obviously, this reduces the reliability and controllability of TIG welding. This study reviews the variability of weld beads obtained in the TIG process, with small changes in chemical composition of the base metal, and A-TIG and TIG weldings with active gas. Aspects that are similar and unique to each case are highlighted and discussed. The mechanisms of weld bead shape presented in the literature are also presented and compared.

The choice of weld bead size in the case of welded cruciform joints can be problematic, especially when the sheets forming the joint are of differing thickness. Technological standards generally recommend a weld bead thickness less than the minimum thickness of the sheets to be joined, whereas structural standards do not envisage any dependency between joint static and fatigue strength and weld bead dimensions, unless these are so reduced as to lead to failure starting and propagating in the weld bead itself rather than the base metal plates. The scope of this study is the theoretical and experimental analysis of the change in fatigue strength with varying weld bead thickness and minimum welded plate thickness.

The structure of a Zr–Cu–Ni–Al glassy sample, successfully welded with an electron-beam technique, is investigated. The results indicate that the weld bead retains its glassy structure, though some medium range order zones appear to form after welding, while the heat-affected zone lying 1–2 mm from the weld bead contains a small fraction of oblong nanocrystals 1–3 nm in width. The results represent successful welding of glassy samples.

and the onset of high speed weld bead defects. Various phenomenological models of humping and undercutting have been proposed that were based on observations of events in different regions within the weld pool or the final weld bead profile. The ability of these models to predict the onset of humping or undercutting has not been satisfactorily demonstrated. Furthermore, the proposed formation mechanisms of these high speed weld bead defects are still being questioned. Recent welding techniques and processes have, however, been shown to be very effective in suppressing humping and undercutting by slowing the backward flow of molten metal in the weld pool. This backward flow of molten weld metal may be the principal physical phenomenon responsible for the formation of humping and undercutting during high speed fusion welding.

Finding suitable characteristic parameters of topside weld pool to reflect the penetration is a key work in weld shape control. In this paper, by analysing the molten metal volume, the relationship between topside weld bead shape and penetration in pulsed gas metal arc welding (PGMAW) is revealed, and then several weld bead characteristic parameters (WBCPs) are proposed to determine the penetration. However, these WBCPs are difficult to be obtained in real time, because continuous solidifying of weld pool forms the weld bead, and the WBCPs can be reflected by the weld pool geometry. Therefore, some weld pool characteristic parameters (WPCPs) are proposed to replace the WBCPs. Furthermore, a visual system is established and a series of image processing arithmetics are developed to extract the WPCPs.

There is an increasing interest in the use of the 9-12%Cr grades of ferritic steel containing Mo, V, Nb, N and W with further possible Co additions, for high temperature applications. There is a parallel need for weld metal development to match these materials. A series of weld metals, based on 9CrMoV but with Cu and Co additions and W replacement of the Mo, have been examined and the effects on delta ferrite distributions and contents identified. The results show that the compositional differences have a direct effect on the delta ferrite content. The delta ferrite form and content are different for the last weld bead, or the as deposited structure, and the centre of the weld pad, where the structure has been reheated by subsequent weld beads. In general, a blocky form of ferrite is associated with the as deposited weld bead and an intergranular form for the reheated weld metal positions but these are not exclusive. A simplified mechanism is proposed for explaining the ferrite distribution. Final...

Investigations were carried out into the formation of a characteristic defect – the displacement of the surfacing bead from the axis of symmetry of the ridge of the labyrinth seal in repair by surfacing with a non-consumable electrode in shielding gases.

Abstract This paper discusses the effect of welding parameters on the size of the heat affected zone (HAZ) and its relative size as compared to the weld bead of submerged arc welding. It is discovered that the welding parameters influences the size of weld bead and HAZ differently which can be relate to the effect of welding parameters on the various melting efficiencies. This difference in behavior of HAZ and weld bead can be explored to minimize the harmful effect of HAZ in future welds.

Summary in the field of structural design of light alloy ships, this paper deals with the experimental determination of fatigue strength of some structural welded details. This concerns unusual geometries of welded joints due to the combination and overlapping of different weld bead shapes. These details have been reproduced on specimens and tested under fatigue loading. The influences of welding process combinations have been verified and experimental results compared to the reference curves given by international design standards concerning simpler welded joints.

While the effects of welding parameters on the shapes of single weld beads have been extensively studied, less is known about how bead shape and penetration alter in multipass welding. In this paper are described studies on the shapes of overlapping beads in manual metal arc cladding of ferritic steel by austenitic stainless steel. Different deposition techniques were used to vary bead positioning and the degree of overlap, and the effects on bead height, width, penetration, and dilution were determined. It is shown that various changes in these parameters occur when weld beads are overlapped. The most important effect is a reduction in penetration and dilution, which is especially marked when the position of arc impingement is on the previous weld bead rather than the base plate. The implications for ultrasonic inspection of clad components, and for weld modelling, are discussed.