Search results

The WELDING INSTITUTE was formed three and a half years ago by amalgamating the British Welding Research Association with the Institute of Welding. BWRA was a body devoted to the carrying out of research. The Institute of Welding was a profession institution. They were brought together in 1967 under the name of the WELDING INSTITUTE. Both parent bodies had been active in training, each for its own purpose. Bringing them together produced a new body strong in the training aspect, which saw its training interest in the area of the technician engineer, the technologist, the supervisor and the manager, rather than at operator level. Although the WI does not carry the words research association in its title, it is a formal research association deriving part of its income from Mintech grant. It is the body with the major research interest in its field. Director of Education: R. P. Newman, C.Eng. Chief Training Officer: L. M. Gourd, B.Sc. Address: The Welding Institute, Abington Hall, Abington, Cambridge. Tel: Linton (nr Cambridge) 591.

This paper outlines the range of robots available and in use in Britain for arc welding, and gives examples of typical current industrial applications. Work at the National Engeering Laboratories and the Welding Institute has the objective of increasing the range and ease of robot arc welding, and recent developments in this area are introduced.

There is a baffling number of sensors suitable for the automatic control of welding. Research at The Welding Institute (TWI) should help industry to make the right choice of sensor for a given requirement and application.

Welding is becoming increasingly unacceptable as a manual job and this is causing an acceleration in the trend towards automation. This paper briefly reviews some recent efforts at automating welding processes, including a program in the UK by the National Engineering Laboratory and the Welding Institute, and considers the future progress and effects of automation in this field.

The world's most powerful electron‐beam welding facility was officially commissioned in September, providing 75 k\V of beam power in a vacuum chamber measuring 7 × 3.6 × 3.6m. Single pass welds in steel up to 200m thick may be produced at high speed and prototype fabrications may be welded in the large chamber using numerically controlled manipulating equipment.

The dramatic expansion in the use and capability of electronic devices in recent years has been facilitated by the substantial development of production techniques. Modern electronic circuits as used in the computer, defence, aerospace, vehicle and domestic appliance industries contain a great many joints and these have to be made reliably and economically without degrading sensitive circuit components. This article describes the major microjoining developments currently of interest to the microelectronics industry, with emphasis on the work conducted by the microjoining section of The Welding Institute, much of which has been directly sponsored by the UK Ministry of Defence (DCVD).

Welded components are often subjected to variable amplitude service loads, increasing the uncertainty of fatigue life due to material strength, notch geometries, defect content and residual stresses. In the case of friction stir welding (FSW) of aluminium alloys no data were found available concerning fatigue behaviour under variable amplitude loading. The purpose of this paper is to determine the fatigue strength of friction stir welds in AA6082‐T6 under constant and variable amplitude loading and analyse the validity of Miner's rule for these specific welding conditions.

Fatigue tests were carried out in a servo‐hydraulic testing machine using a stress ratio of R=0. Typified Gassner amplitude spectra were considered, using four shape exponent values. Microhardness tests were performed to characterize the Vickers hardness profile in the vicinity of the weld area. Relatively to the base material (BM), the FSW process leads to a decrease of the static mechanical properties.

Detailed examination revealed a hardness decrease in the thermo‐mechanically affected zone and the nugget zone average hardness was found to be lower than the base alloy hardness. The comparison with data collected from the literature shows that FSW specimens present higher fatigue resistance than specimens welded by metal inert gas and tungsten inert gas processes. However, they still have lower fatigue lives than the BM. Using the equivalent stress calculated by Miner's rule, a good agreement was observed between constant and variable fatigue loading results. The characteristic curve obtained for friction stir welds is higher than the International Institute of Welding (IIW) fatigue class for fusion welds with full‐penetration both‐sided butt joints.

No data are available concerning fatigue behaviour under variable amplitude loading for friction stir welds of aluminium alloys. Furthermore, this paper analyses the fatigue strength of friction stir welds in AA6082‐T6 under constant and variable amplitude loading in order to verify the validity of Miner's rule for this specific welding process. A comparison between characteristic fatigue curves, using IIW fatigue classes (FAT), is also performed.

Automating the welding process for the shipbuilding industry is very challenging and important, as this industry relies heavily on quality welds. Conventional robotic welding systems are seldom used because the welding tasks in shipyards are characterised by non‐standardised workpieces which are large but small in batch sizes. Furthermore, geometries and locations of the workpieces are uncertain. To tackle the problem, a Ship Welding Robot System (SWERS) has been developed for the welding process. The main features of the SWERS include a special teaching procedure that allows the human user to teach the robot welding paths at a much easier and faster pace. In addition, operation of the system is made easier through a custom designed man‐machine interface. Through this interface, only a few buttons need to be pressed to command the robot into different modes. Optimised welding parameters can be selected from a large database through a Graphical User Interface system.

Points out that the pitting resistance of welds in stainless steels is often inferior to the parent metals, and is an important factor to consider during the selection of materials of service in corrosive environments. Notes that an empirical pitting resistance equivalent (PRE), often expressed as PRE = % Cr + 3.3 × % Mo + 16 × % N, is used to rank different parent metals and that during welding, a number of metallurgical‐and surface‐related reactions take place locally, which make it impossible to predict the pitting corrosion resistance by a single expression. Reviews the effects of oxides, slag and other weld defects on the pitting resistance of welds in stainless steels, and highlights the importance of including the properties of fabricated areas into the life cycle cost (LCC) analyses.

Three-dimensional (3D) printing, one of the important technological pillars of Industry 4.0, is changing the landscape of future manufacturing. However, the limited build volume of a commercially available 3D printer is one inherent constraint, which holds its acceptability by the manufacturing business leaders. This paper aims to address the issue by presenting a novel classification of the possible ways by which 3D-printed parts can be joined or welded to achieve a bigger-sized component.

A two-step literature review is performed. The first section deals with the past and present research studies related to adhesive bonding, mechanical interlocking, fastening and big area additive manufacturing of 3D printed thermoplastics. In the second section, the literature searches were focused on retrieving details related to the welding of 3D printed parts, specifically related to friction stir welding, friction (spin) welding, microwave and ultrasonic welding.

The key findings of this review study comprise the present up-to-date research developments, pros, cons, critical challenges and the future research directions related to each of the joining/welding techniques. After reading this study, a better understanding of how and which joining/welding technique to be applied to obtain a bigger volume 3D printed component will be acquired.

The study provides a realistic approach for the joining of 3D printed parts made by the fused deposition modeling (FDM) technique.

This is the first literature review related to joining or welding of FDM-3D printed parts helping the 3D printing fraternity and researchers, thus increasing the acceptability of low-cost FDM printers by the manufacturing business leaders.