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The formation of internal stresses is mainly caused by contraction of the material. As the magnitude of shrinkage is dependent upon many factors, it cannot be predicted with accuracy. Not only the technique and the rate of welding are of importance but also the material and the design. Finished welded components often show quite considerable reductions in their major dimensions. With larger welded structures, such as engine mountings and steel tube fuselages, which ought to have certain dimensions absolutely accurate for assembly requirements, the contraction and the distortion duo to welding should be considered in every case.

WHEN metal parts are exposed to alterations of temperature, their outer dimensions undergo a change. With rising temperatures metals expand, with falling temperatures they contract. If different temperatures exist within one and the same metal member, internal stresses begin to act, causing a deformation of the component and thus setting up internal strains. Cracks, buckling, distortion and shrinkage are the external results of such strains.

This paper aims to demonstrate the benefits of using different impeder materials for induction tube welding systems.

To show the difference in using various impeder materials, a new approach was taken to model tube welding systems in two and three dimensions. Three-dimensional (3-D) electromagnetic models were used to determine the current distribution along the weld vee as well as the permeability of the tube along the length of the welding system. Two-dimensional (2-D) coupled electromagnetic plus thermal models with rotational movement were used to determine the temperature distribution in the heat-affected zone.

Simulation results suggest upwards of 25 per cent system power savings when using a soft magnetic composite (SMC) impeder rather than the traditional ferrites.

There is currently a lack of experimental data to validate the models, but future work will include comparison of models to real-world trials.

When dealing with tube welding systems, there are possibilities to improve process efficiency or increase production quality and output by improving the impeder material.

While simulations of tube welding systems have been done previously, studies on improving impeder materials are rarely carried out. This paper brings to light possible improvements to be made to induction tube welding systems.

Quality of the weld joint produced by high-frequency induction (HFI) welding of steel tubes is attributed to a number of process parameters. There are several important process parameters such as the speed of the welding line, the angle of the approaching strip edges, the physical configuration of the induction coil, impeder, formed steel strip and weld rolls with respect to each other, the pressure of the weld rolls and frequency of the high-frequency current in the induction coil. The purpose of this paper is to develop a 3D model of tube welding process that incorporates realistic material properties and movement of the strip.

3D numerical simulation by the finite element method (FEM) can be used to understand the influence of these process parameters. In this study, the authors have developed a quasi-steady model along with the coupling of electromagnetic and thermal model and incorporation of non-linear electromagnetic and thermal material properties.

In this study, 3D FEM model has been established which gives results in accordance with previously published work on induction tube welding. The effect of the Vee-angle and frequency on the temperature profile created in the strip edge during the electromagnetic heating is studied.

The authors are now able to simulate the induction tube welding process at a more reasonable computational cost enabling an analysis of the process.

A 3D model has been developed for induction tube welding. A non-linearly coupled system of Maxwell’s electromagnetic equation and the heat equation is implemented using the fixed point iteration method. The model also takes into account non-linear magnetic and thermal material properties. Adaptive remeshing is implemented to optimise mesh size for the electrical skin depth of induced current in the strip. The model also accounts for the high welding-line speeds which influence the mode of heat transfer in the strip.

THE possibility of explosive cladding was first recognised in 1957, when it was noted in explosive forming that if a metal die was employed and an excessive charge was used then the metal sheet which was being formed became welded to the die. Since that time numerous papers have been published, for instance Davenport and Duvall (Ref. 1), Pearson (Ref. 2), Holtzman and Ruderhausen (Ref. 3), Boes (Ref. 4), and Bahrani and Crossland (Ref. 5) to mention but a few. All the early work was devoted to the application of cladding, and it is only during the last two or three years that the applicability of the process to tube welding, lap welding, welding of tees has been mentioned. At the present time the main potential fields of application are to the cladding of dissimilar metals over large areas and the welding of tubes to tube plates.

Tube welding in the modern era of space applications requires a very high degree of quality in addition to productivity. Modern techniques in automated tube welding provide the tools necessary in today's requirement for high degree of control of quality in production. These tools are a by‐product of performing the automated process via computer control. Since all the pertinent parameters are resident within the computer memory, a reformating and recording of a current welding status and deviations from preprogramed commands is readily available. The nature of cyber‐based controlled systems provides production and quality control management with the tools necessary to carefully control the welding parameters that go into automated welding of tubing. Consequently, the detailed logging of the welding process is available for a post‐weld report. Most problems that occur in producing a quality product are absence of management tools to completely control the welding process. This is because of the nature or manner in which the welding process is performed by the operator and the quality procedures that are followed for recognizing problems and identifying the cause(s) of the problems. The following paper provides the techniques that are currently available for use in managing such production problems and successful case histories in the implementation of these cyber‐based tools.

Development of non‐destructive methodology for detection of arc strike, spatter and fusion type of welding defects which may form on steam generator (SG) tubes that are in close proximity to the circumferential shell welds. Such defects, especially fusion‐type defects, are detrimental to the structural integrity of the SG. This paper aims to focus on this problem.

This paper presents a new methodology for non‐destructive detection of arc strike, spatter and fusion type of welding defects. This methodology uses remote field eddy current (RFEC) ultrasonic non‐destructive techniques and K‐means clustering.

Distinctly different RFEC signals have been observed for the three types of defects and this information has been effectively utilized for automated identification of weld fusion which produces two back‐wall echoes in ultrasonic A‐scan signals. The methodology can readily distinguish fusion‐type defect from arc strike and spatter type of defects.

The methodology is unique as there is no standard guideline for non‐destructive evaluation of peripheral tubes after shell welding to detect arc strike, spatter and fusion type of welding defects.

The purpose of this paper is to present two simulation strategies for tube induction welding process. Coupled electromagnetic and thermal problem is solved by applying 3D FEM models. The resulting power density and temperature distribution are compared.

FE analysis has been used in order to compute the magnetic and thermal field in a suitable 3D model.

Two strategies for coupled magnetic and thermal simulation with movement are proposed.

Reported strategies can be used to design tube induction welding devices and to verify the influence of the main parameters of the process, i.e. welding velocity, frequency, specific and total power.

The paper summarizes two different simulation strategies taking into account the movement of the tube through the inductor. In the first strategy, the tube heating is simulated by providing the mean power absorbed by a tube section crossing the inductor. In the second strategy, a spatial translation of the material properties is implemented.

Low performance life and increased machine downtime due to wear of resistance welding copper electrode is of major concern in fin–tube resistance welding in waste heat recovery boilers. The purpose of this study is to investigate an alternative material with good wear resistance to replace the currently utilized C11000 electrolytic tough pitch (ETP) copper electrode.

In this study, a Cu-Cr-Zr ternary alloy was developed for fin-to-tube welding electrode by melting commercial grade electrolytic copper (99.9% purity) plates, chips of chromium, powder of zirconium at 1100°–1300°C, followed by hot forging and precipitation hardening at 450°–550°C to attain appropriate grain flow. Microstructures of Cu-Cr-Zr alloys were analysed using scanning electron microscopy coupled with energy-dispersive backscatter electron spectrometry.

Wear performance of Cu-Cr-Zr and C11000 ETP Cu was evaluated using pin-on-disc set-up with Taguchi’s L₈ orthogonal array. Ranking of the parameters was done, and it was observed that the material and temperature play a very significant role in controlling the wear of an electrode.

Rate of fin–tube resistance welding was increased by 26% with Cu-Cr-Zr alloy. Further investigation on effect of plasma on the metallurgical characteristics of Cu-Cr-Zr is recommended.

Tribo-mechanical performance of newly developed Cu-Cr-Zr ternary alloy was compared with C11000 ETP copper.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2023-0092/

Discusses the forthcoming installation of an ABB Flexible Automation beam preparation system at an offshore platform construction company in Scotland. Using a six‐axis robot suspended from a boom, the system will be able to cut beams to any length with any desired end profile using an Arithmetic Robot Application Control [ARAC] system, which allows virtually any beam profile to be programmed into the system, in seconds by means of ARAC macros. Prior to cutting, the robot will exchange its gas torch for a 3‐D probe to measure the actual beam dimensions and compare these with the stored data design. Describes how the ARAC software package works and gives examples of other applications such as the cutting of round tubes for structural assemblies, multi‐pass welding and tube‐to‐sheet welding.