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With the advancement of the manufacturing industry, performing submerged arc welding subject to varying welding heat inputs has become essential. However, traditional thermodynamic models are insufficient for predicting the effect of welding heat input on elemental transfer behavior. This study aims to develop a model via CALPHAD technology to predict the influence of heat input on essential elements such as O, Si, and Mn when typical SiO2-bearing fluxes are employed. The predicted data demonstrate that the proposed model effectively forecasts changes in elemental transfer behavior induced by varying welding heat inputs. Furthermore, the study discusses the thermodynamic factors affecting elemental transfer behavior under different heat inputs, supported by both measured compositions and thermodynamic data. These insights may provide theoretical and technical support for flux design, welding material matching, and composition prediction under various heat input conditions subject to submerged arc welding processes when SiO2-bearing fluxes are employed. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The use of shielded metal arc welding (SMAW) equipment to synthesize alloys is one of the most promising methods as it can be used for in-situ fabrication. The hardness and corrosion properties of the deposited layer during the welding process can be enhanced by dilution of nichrome (NiCr) during the process. Therefore, the alloy was synthesized on the surface of the mild steel using SMAW equipment with various NiCr additions. The properties of the alloy were investigated using an X-ray diffraction (XRD), an Optical microscope, a Potentiostat, and a Vickers hardness apparatus. The appearance of martensite overlaps with the ferrite phase could be affected by the addition of NiCr to the alloy. An increase in NiCr content is followed by an increase in the lattice parameter value of the ferrite phase. The presence of a certain amount of nickel (Ni) contributes to the formation of lower transformation phases, including martensite. At the same time, the incorporation of chromium (Cr) also plays a significant role in promoting the formation of acicular ferrite. An increase in NiCr content in NiCr2 and NiCr3 samples results in a quantitative increase in martensite formation. Adding 0.434 g of NiCr to the weld deposited layer could result in the corrosion rate of the alloy being 0.1118 mm/y. Higher hardness is found in the NiCr3 sample, around 742.06 HV.

The work was carried out as part of a project to improve the corrosion resistance of welded joints. The optimal selection of input parameters reduces the consumption of welded material as well as the negative impact on the environment. The samples were welded by electrical resistance welding, more precisely by cross-wire welding. Electric resistance welding is a process for welding with electricity in which of high electrical resistance is used to generate heat at the contact point of the welded parts. Steel wire S235 with a diameter of 4 and 3 mm was used. The article shows the creation of the model to predict the percentage of setdown and weld strength as a function of the input parameters, welding current and welding time. The first task was to create a Design of experiments in which the process parameters or the range of input parameters are determined. The Design of the experiments was created for both wire diameters. This covers the range of parameters with which a welded joint of wires can be realised. A statistical analysis of the process follows, where it was found that for 4 and 3 mm diameter wires the percentage setdown increases with increasing welding current and time. An increase in strength as a function of welding current and welding time is also observed, but the results overlap in most cases and the range of their values is greater than that of setdown. The appearance of the weld was analysed for each sample. The visual inspection revealed seven categories of welds, which were divided into two groups, i.e. good and poor welds. All results were listed in a table with the percentage of expectation for a particular category of weld appearance. Based on the analysis, a model for determining the welding result parameters depending on the specified input parameters was developed, which can be used in practise to support the management of the electric resistance welding process. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To fulfill the need to limit automotive emissions, reducing vehicle weight is widely recommended and achieved in many ways, both by the construction of individual elements of the vehicle and by the selection of light materials, including Al alloys. Connecting these elements with each other and with elements made of iron alloys can be realized, inter alia, by welding or stir welding. However, the quality of the welds obtained varies widely and depends on many design, operational, and environmental factors. The present study focused on a review of various welding techniques used to join both similar and dissimilar Al alloys utilized in the automotive industry, the effect of various process parameters on weld quality, and the phenomena observed in such welds. The research methodology was based on the analysis of the content of articles from main databases. Apart from capturing the current state of the art, this review evaluates reaching the possible highest joint quality and welding process disadvantages such as porosity, poor surface quality, a tendency toward hot cracking, and low ductility for the Al alloys applied in the automotive industry. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The work was carried out as part of a project to improve the corrosion resistance of welded joints. The optimal selection of input parameters reduces the consumption of welded material as well as the negative impact on the environment. The samples were welded by electrical resistance welding, more precisely by cross-wire welding. Electric resistance welding is a process for welding with electricity in which of high electrical resistance is used to generate heat at the contact point of the welded parts. Steel wire S235 with a diameter of 4 and 3 mm was used. The article shows the creation of the model to predict the percentage of setdown and weld strength as a function of the input parameters, welding current and welding time. The first task was to create a Design of experiments in which the process parameters or the range of input parameters are determined. The Design of the experiments was created for both wire diameters. This covers the range of parameters with which a welded joint of wires can be realised. A statistical analysis of the process follows, where it was found that for 4 and 3 mm diameter wires the percentage setdown increases with increasing welding current and time. An increase in strength as a function of welding current and welding time is also observed, but the results overlap in most cases and the range of their values is greater than that of setdown. The appearance of the weld was analysed for each sample. The visual inspection revealed seven categories of welds, which were divided into two groups, i.e. good and poor welds. All results were listed in a table with the percentage of expectation for a particular category of weld appearance. Based on the analysis, a model for determining the welding result parameters depending on the specified input parameters was developed, which can be used in practise to support the management of the electric resistance welding process.

Copyright of Steel Pipe is the property of Steel Pipe Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the full-automatic welding joint of X52 line steel, the welding process parameters were adjusted and optimized while fully considering the mutual influence of double torch and the influence of construction environment. Mechanical tests such as tensile test, bending test, nick break test, and hardness test were conducted to verify the reliability of the welding process, forming a welding process evaluation; At the same time, the problems encountered in on-site welding were analyzed and solved, and the key points for optimizing the welding process parameters of dual torch automatic welding were summarized, forming a full-automatic welding technology with copper backing for X52 pipeline steel. By conducting metallurgical analysis and hardness test on the weld seam, the distribution of the microstructure of the weld metal was analyzed from a microscopic perspective. The positive correlation between the hardness distribution of the X52 pipeline steel weld seam, heat affected zone, and base metal and the content of pearlite in the corresponding metallographic structure was obtained, further verifying the consistency of the metallographic structure of the weld metal and heat affected zone under the welding process conditions. The results indicated that the full-automatic welding process for copper liners could be applied to the welding of large diameter steel pipe, and the use of this process could significantly improved welding quality and efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Guangdong Architecture Civil Engineering is the property of Guangdong Architecture Civil Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Welding is a widespread process requiring substantial amount of energy and generating high carbon emissions, so calculating and reducing its carbon footprint is crucial to make it more sustainable. This paper compares welding methods (RLW, GMAW) regarding their carbon emissions and provides guidelines to identify Carbon Intensive Elements (C.I.E.). A mathematical model is employed for theoretical calculations and Life Cycle Assessment for analytical ones. Carbon emissions are normalized per welding parameters, showing that RLW is more carbon efficient than GMAW. Based on the approach used and produced results, a strategical framework developed as a roadmap to identify the most C.I.E. [ABSTRACT FROM AUTHOR]

In submerged arc welding, evaluating elemental transfer behaviors is critical for selecting and designing welding materials. Accurate assessment of O, Si, and Mn transfer behavior is essential for ensuring process quality, particularly when silicon-manganese fluxes are applied. Traditional quantification methods, however, focus only on chemical reactions in the weld pool zone, potentially overlooking the cross-zone elemental transfer behavior and leading to significant predictive inaccuracies. This study investigates the CaO-SiO2-MnO flux, a prevalent silicon-manganese flux, focusing on O, Si, and Mn, which exhibit notable transfer behaviors of O, Si, and Mn. By employing a multi-zone approach and integrating various scientific principles, the research aims to improve the accuracy of predicting elemental transfer behaviors and deepen the understanding of the metallurgical processes in submerged arc welding when silicon-manganese fluxes are employed. The study proposes strategic enhancements to traditional quantification methods, which may offer valuable insights for the improvement of industry standards. This study demonstrates that considering only the local thermodynamic equilibrium of the weld pool zone when quantifying the transfer behavior of elements may lead to predictive errors, especially for easily evaporating metallic elements. By incorporating a cross-zone assessment for submerged arc welding process, i.e., introducing new quantifying parameters (Δd and Δw), the predictive accuracy of the transfer behavior of elements and their cross-zone actions can be enhanced. [ABSTRACT FROM AUTHOR]

Producing soundness weldments is the main goal to avoid catastrophic failures that occur in oil refineries, where the interaction of internal defects and residual stress with the working conditions leads to human and financial losses. AISI 1020- A106 carbon steel pipes that are used for oil products transmitted inside oil refineries have a 55 mm inner diameter with a 5 mm thickness and had been welded with shielded metal arc welding (SMAW) for the first samples group, while the second group was welded using gas tungsten arc welding (GTAW) process. For surface defects detection the liquid penetration method was used, while for internal defects radiography method was used, and for residual stresses X-ray diffraction was used. The results showed that the first group of samples contained different types of internal defects with compressive residual stresses, while the second group was nearly clear of internal defects with tensile residual stresses. [ABSTRACT FROM AUTHOR]

Atomic investigation of many common phenomena can be included as interesting achievements. Using these achievements makes it possible to design promising structures for various actual applications. The current research describes the mechanical performance of Ag and Cu samples after welding at various initial pressures. For this purpose, the Molecular Dynamics (MD) approach is used via the LAMMPS package. Technically, MD simulations are done in 2 main steps. Firstly, the atomic stability of welded Ag-Cu samples is described at various initial conditions (initial pressure). Then, tension test settings are implemented in equilibrated systems. The MD outputs indicate that the physical stability of the welded samples was altered by changing the initial pressure between 1 and 10 bar. Simulation results predict that the mechanical resistance of atomic samples decreases by enlarging the initial pressure. Numerically, the ultimate strength of the Ag-Cu matrixes decreases from 1.424 MPa to 1.241 MPa by increasing the initial pressure from 1 bar to 10 bar, respectively. This mechanical performance arises from atomic disorder created inside samples. So, it is expected that initial condition changes affect the atomic evolution of welded metallic samples, and this phenomenon should be considered in the design of mechanical structures in industrial cases.

Copyright of TDRI Quarterly Review is the property of Thailand Development Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geopolymer materials have long been known for their competitive properties against traditional construction materials. Their special features include high resistance to elevated temperatures and good fire resistance. They are typically used as insulating materials at temperatures not exceeding 100 °C (because they can achieve a thermal conductivity coefficient of 0.060 W/m × K or less under these conditions). Still, they can also be used as thermal insulation at temperatures exceeding 1000 °C. One technology that uses very high temperatures is metal welding technology, where temperatures often exceed as many as 3000 °C. Geopolymers, due to their properties, can also be an interesting new alternative in various welding applications. This paper presents the preliminary results of pot-proofing the resistance of geopolymers to temperatures exceeding 3000 °C. Test results of a foamed geopolymer insulating a steel substrate are presented, and a geopolymer mold for thermite rail welding was made and realistically tested. The results confirmed the feasibility of using cast geopolymer molds for thermite welding of railroad rails. The geopolymer material performed well during the test and no cracks or other damage occurred. The following article presents the potential of using geopolymer materials for welding applications. [ABSTRACT FROM AUTHOR]

This work aims to improve the durability of the deep-sea transportation pipeline's weld, prolong the pipeline's service life, and ensure the safe and efficient operation of the transportation work. By analyzing the influence of welding parameters on the welding residual stress (WRS) of X80 pipeline steel, the welding process is improved to improve the durability of the welded joint. The WRS of the plate butt joint was measured by the hole-drilling method and X-ray diffraction method; the WRS of the pipe butt joint was measured by the hole-drilling method. The experimental results are compared with the numerical simulation results. The relationship between process parameters and welding residual stress is obtained by simulating WRS of flat plate and circular pipe butt joint under different welding process parameters. The results show that the experimental data measured by X-ray diffraction and the hole-drilling method agree with the results of numerical simulation. The WRS of the two plates decreases with the increase in welding speed and backing thickness, increasing with laminate thickness, welding line energy, and groove angle. The WRS value can be obtained by changing the butt plate welding process, and the WRS value of the tube can be inferred under the same condition. We use ANSYS software to study the temperature field and stress field in the welding process based on the butt plate test. The welding process of pipeline steel is numerically simulated, and the numerical results are verified by the infrared thermal imager, X-ray diffractometer, and blind hole method. The butt pipe test is used as the modeling prototype to study the temperature field and stress field in the welding process. The thermal-solid coupling calculation of the pipeline steel welding process verified the simulation results by the infrared thermal imager and the hole-drilling strain-gage method. Finally, taking the welding speed, welding line energy, backing thickness, test plate thickness, and groove angle as variables, the changing trend of welding residual stress of the two models under different welding process parameters is studied. It can reduce the welding residual stress, prolong the service life of pipeline steel, reduce the cost and save resources. [ABSTRACT FROM AUTHOR]

Assessing the occupational health and safety (OHS) factors in the welding process is necessary to determine the workers' perception of what contributes to their safety and health in the workplace. This would provide insight for stakeholders to aid them in their occupational safety and health programs. The non-probability sample technique utilized in this study is purposive sampling using an online survey. Welders in Singapore are the intended participants. The self-administered online survey was conducted using Google Forms. The hypothesis test's beta coefficient and R2 results were used to evaluate the model using partial least squares structural equation modeling (PLS-SEM). The study's results revealed that safety culture has the highest association with top management attitudes toward safety and health in the workplace. Similarly, safety training was also found to have a strong association with employees' attitudes towards safety. Finally, factors such as compliance with safe working conditions, safety programs, and the absence of and lack of exposure to harmful agents were also proven to have a significant association with safety and health in the workplace. This study benefits not only those businesses conducting the welding process but also employees to better understand the factors contributing to their overall safety at work. [ABSTRACT FROM AUTHOR]

Ultrasonic plastic welding is an efficient and green welding method, which has been widely used in the joining of carbon fiber reinforced thermoplastic composites (CFRTP) in recent years. An important step in the ultrasonic welding of CFRTP is the design of the welding joint, which largely determines the weld quality. An ultrasonic CFRTP welding method based on structured surfaces was proposed, that is, the surface of the workpiece is structured by ultrasonic embossing before welding, and energy director are processed. Taking carbon fiber reinforced nylon 66 (CF/PA66) as the research object, the effect of structured surface and welding energy on the weld formation was studied. Microstructure, tensile-shear performance and fracture characteristics of welded joint were analyzed. The results show that compared with the unstructured surface, the structured surface acting as energy director that can effectively concentrate welding energy and greatly reduce the randomness and dispersion of weld distribution, thereby improve the weld quality. Moreover, fewer defects in the weld joint can be obtained by pre-structuring two contacting surfaces.

This paper investigate the geometric morphologies, microstructure, and porosity of the aluminum alloys laser welding joints (ALWJ) under various welding processes through a series of tests, including the optical microscope (OM) and computed tomography (CT) tests. The mechanical properties are subsequently analyzed by the tensile tests and finite element simulation. A prediction model that considers the role of geometry and porosity is proposed to predict the ultimate strength of ALWJ. Results show that the geometries significantly depended on the welding process, particularly for the penetration depth, which increases with the elevation of heat input, increasing the mechanical strength of joints. The T-joint is not connected correctly when the heat input is less than 42.8 J mm−1, which increases with the elevation of heat input until the heat input researches to 60 J mm−1. But the higher heat input also induced more pores due to the burning damage of the magnesium (Mg) element, which deteriorates the mechanical strength. Finally, the developed strength prediction model is proved to be accurate and reliable enough to predict the strength of the ALWJ with pore defects. The error of the predicted values compared with the experimental is within 15%. [ABSTRACT FROM AUTHOR]

In order to facilitate the transportation of the wind turbine tower, the tower is made of several separate parts and they are flanged to each other and fixed by the welding process. An unwanted consequence in the welding process is the distortion caused by the uneven distribution of heat in the flange. This consequence appears as residual stress and permanent deformations in the flange. In this research, the distortion in the welding of the wind turbine tower flange is studied. Numerical and experimental results show that the amount of heat flux has the greatest effect on flange distortion. By writing a subroutine and using repetition and conditional loops, the path of the welding nozzle is defined for the program and the amount of distortion caused by the heat distribution is predicted with appropriate accuracy. The comparison of numerical and experimental results shows that the difference of the displacement results depends on the cross-sectional area of the flange and its angular position. In the outer region of the flange, this difference is close to zero percent in all positions. In the middle areas of the cross-section in the angular position of 60 degrees, this difference is 33%, which has the lowest percentage difference compared to the positions of zero, 30 and 90 degrees. In the inner areas of the flange at an angular position of 30 degrees, the displacement difference is 14%, which is the least difference compared to other positions. [ABSTRACT FROM AUTHOR]

Due to the cost efficiency of welding repairs, the use of transient thermal tensioning (TTT) has begun to be applied to minimize distortion and residual stresses, particularly on thin plates. However, it requires a long preheating time especially on large structures, so that the efficiency of welding process cannot be maximized. Application of TTT treatment using flame heater on TTT treatment which require no preheating time so that welding efficiency can be increased. The aims of this study are to investigate the TTT treatment in reducing distortion, investigate the effect of TTT treatment on tensile strength and hardness, investigate the microstructure and its effect on tensile strength and hardness, investigated the effect of TTT treatment on fatigue crack growth rate. In this research, TTT treatment was performed by flame heating on the both side of weld line integrated in welding process. Temperature in both side plates were controlled and measured using thermocouple. The tests on the weld joints were carried out including distortion measurement, microstructure examination, hardness measurement, tensile test and fatigue test. Results showed that the TTT (–60) treatment is the most effective in decreasing the longitudinal distortion which placing the flame heating a 60 mm behind welding torch. It tends to increase the tensile strength of weld metal supported by its increasing hardness. The increase in the percentage of the acicular ferrite phase is linearly related to the tensile strength and hardness of the weld joint. The fatigue behavior could be improved by TTT treatment (–60) which is associated with the effect of decreasing residual stress in the weld metal region. This treatment is the best parameter in an effort to increase the welding efficiency of the TTT method. [ABSTRACT FROM AUTHOR]

The article reviews the capacities of the acoustic emission method usage to assess the technical condition and integrity of thick-walled welded structures, the quality control of welded joints in multilayer welding. As a result of the analysis of AE control data, the authors propose a set of informative parameters of the AE method, which form a criterion space for separating the reflected signals from defects and signals from interference. [ABSTRACT FROM AUTHOR]

Copyright of Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We present a novel finite element method to solve the thermal variables in welding problems. The mathematical model is based on the enthalpy formulation of the energy conservation law, which is simultaneously valid for the solid, liquid, and mushy regions. Both isothermal and non-isothermal melting models are considered to relate the enthalpy with the temperature. Quadratic triangular elements with local anisotropic mesh adaptation are employed for the space discretization of the governing equation, and a second-order backward differentiation formula is employed for the time discretization. The resulting non-linear discretized system is solved with a simple Newton algorithm with two versions: the  θ -Newton algorithm, which considers the temperature as the main unknown variable, as in most works in the literature, and the h-Newton algorithm, which considers the enthalpy, which is the main novelty of the present work. Then, we show via numerical experiments that the h-Newton method is robust and converges well to the solution, both for isothermal and non-isothermal melting. However, the  θ -method can only be applied to the case of non-isothermal melting and converges only for a sufficiently large melting temperature range or sufficiently small time step. Numerical experiments also confirm that the method is able to adequately capture the discontinuities or sharp variations in the solution without the need for any kind of numerical dissipation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Materials Engineering / Cailiao Gongcheng is the property of Journal of Materials Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article, an improved MULTIMOORA approach is proposed for multi-attribute decision making (MADM) using the fuzzy concept, best–worst method (BWM) and half-quadratic (HQ) theory. The fuzzy concept helps to capture the vague information derived from human judgement at different stages of decision making, while BWM helps to simplify the attribute weighing. The standard MULTIMOORA method uses three utility functions, namely the ratio system (RS) utility function, reference point (RP) utility function and full multiplicative form (FMF) utility function, for evaluating the alternatives and obtaining the ranking orders using each of the utility function scores, which are consolidated using dominance theory. However, the dominance theory in the existing MULTIMOORA method has limitations, like there is no way to ascertain the trust level of the consolidated ranking and the level of consensus among the three ranking orders. Also, there is a need for multiple comparisons during aggregation, difficulty in automation, and the problem of circular reasoning. To overcome the limitations of dominance theory, a new HQ theory-based aggregation procedure has been proposed in this paper, which also has two associated indices, one to ascertain the level of consensus from the three ranking orders from MULTIMOORA and the other to ascertain the trust level or reliability of the final ranking in the aggregated ranking. The new modification is expected to add to the trustworthiness of the MULTIMOORA decision tool. The applicability of the proposed approach has been demonstrated with cases on welding process selection. [ABSTRACT FROM AUTHOR]

Arc welding processes, such as shielded metal arc welding (SMAW), metal inert gas (MIG), and tungsten inert gas (TIG), play an important role in industrial applications. To improve the efficiency of the exploitation of traditional welding systems, new technologies have been used. Virtual reality technology is one of them. The virtual reality (VR)-based welding system enables to increase the frequency of practice to help learners obtain welding experience to avoid errors that occur during actual welding processes. This paper presents a VR-based system for simulating three welding processes: SMAW, MIG, and TIG. The developed system includes hardware components and VR software installed on a computer. The change in the physical devices, such as moving the welding torch and the distance from the welding torch to the plates to generate the weld bead, will update in real time and appear on the virtual environment. The functionality of the developed system for simulating the welding processes, such as in the real welding environment, was tested successfully. For implementing the system, welding speed and the distance from the welding torch to the plates are important process parameters, which determine the weld size or the weld formation. In this research, the ranges of the welding speed are 70 ÷ 120 mm/min; 240 ÷ 460 mm/min; and 250 ÷ 450 mm/min for the SMAW, TIG, and MIG processes, respectively. These values were tested experimentally. The distance from the welding torch to the plates to display the weld joint is 1.5 ÷ 5 mm. Outside of this range, no weld joint is formed. The welding widths are 4.4 ÷ 12.9 mm, 7.1 ÷ 12.4 mm, and 7.4 ÷ 11.3 mm for the SMAW, TIG, and MIG processes, respectively. [ABSTRACT FROM AUTHOR]

In this paper, an efficiency improvement of a high-speed permanent magnet excited synchronous machine (PMSM) by the use of spot-welding as lamination packaging technology is realized. Welding, interlocking, clinching and gluing are typical technologies to manufacture electrical steel stacks of electrical machines. However, these processes deteriorate the magnetic properties of the steel sheets, thereby decreasing the overall efficiency of the machine. Variations of line-welding (six, eight, twelve, thirty two and forty) line welds and spot-welding procedure is performed and analyzed. A semi-physical iron loss separation approach is used to extract the IEM iron loss model (Eggers et al., IEEE Transactions on Magnetics48(11) (2012), 3021–3024). These parameters are utilized during the finite element simulation to calculate the effective iron loss (efficiency) of the machine while using each joining procedure. A low speed, high-speed and WLTC-c3 driving cycle is exemplarily used to analyze the effects of each procedure on the machine efficiency at the different operating conditions. [ABSTRACT FROM AUTHOR]

A Monte-Carlo-assisted phase field model for the simulation of grain growth in metals and alloys is presented. The simulation time in this model is connected to real time through an experimental data-based kinetic model. Site selection probability is introduced to simulate grain structure evolution under non-isothermal conditions. The grain evolutions with temporal and spatial distributions of temperature during the welding process are comprehensively reproduced. The average size and topological texture of the generated grains in the fusion zone and heat-affected zone are examined. The computed results are compared to experimental data for laser-welding two alloys: Fe–6.5 wt.%Si and low-carbon steel. The applications of real-time–temperature based phase field simulation to material processing indicate significant promise for understanding grain structures during the welding process or additive manufacturing processes. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Laser Technology is the property of Gai Kan Bian Wei Hui and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Geopolymer materials have long been known for their competitive properties against traditional construction materials. Their special features include high resistance to elevated temperatures and good fire resistance. They are typically used as insulating materials at temperatures not exceeding 100 °C (because they can achieve a thermal conductivity coefficient of 0.060 W/m × K or less under these conditions). Still, they can also be used as thermal insulation at temperatures exceeding 1000 °C. One technology that uses very high temperatures is metal welding technology, where temperatures often exceed as many as 3000 °C. Geopolymers, due to their properties, can also be an interesting new alternative in various welding applications. This paper presents the preliminary results of pot-proofing the resistance of geopolymers to temperatures exceeding 3000 °C. Test results of a foamed geopolymer insulating a steel substrate are presented, and a geopolymer mold for thermite rail welding was made and realistically tested. The results confirmed the feasibility of using cast geopolymer molds for thermite welding of railroad rails. The geopolymer material performed well during the test and no cracks or other damage occurred. The following article presents the potential of using geopolymer materials for welding applications.

This paper proposes the conception, design and optimization of an individual exhaustion system for use in a welding laboratory. The verification of the system will consist of experiments to exhaust the fume emitted during manual welding with coated electrode, so that the fume emission reaches minimum values in order to obtain a performance function of the exhaust system. Optimisation of the method has resulted in the retention of 60% of the total dust emitted during welding, and attempts are being made by optimising the filter system or the position of the welder to make this percentage even higher. [ABSTRACT FROM AUTHOR]

Submerged arc welding joins metal by the heating of the electrode, base metal, and flux in the arc plasma, while the weld pool is protected under the granular flux and molten slag. Due to complex chemical reactions occurring between the arc plasma, weld pool, and molten slag (flux), flux essentially affects the weld metal composition, which, in turn, dictates the mechanical properties of the weldment. Therefore, fine-tuning the weld metal composition is essential to ensure a sound weld, and efforts worldwide have been focused on the control mechanism of flux on the weld metal composition. Recently, agglomerated fluxes have been widely applied due to low energy consumption during manufacture. The Cr2O3-bearing agglomerated flux is one of the most commonly used flux types in fields of heavy industrial applications. However, few works concern the element transfer behavior when Cr2O3-bearing agglomerated fluxes are used. Within this framework, typical agglomerated CaF2-SiO2-Na2O-Cr2O3 fluxes with varying Cr2O3 content from 10 to 50 wt.% are designed and applied to Q345A steel. The influence of Cr2O3 content upon the transfer behaviors of essential elements, including O, Cr, and Mn, is quantified and interpreted from the point of thermodynamics. By incorporating a gas-slag-metal equilibrium consideration, the assumptions made in previous studies are justified. Additionally, evidence regarding the loss of Cr and Mn to the arc plasma is provided, and a possible thermodynamic approach to predict element transfer levels is proposed. It is revealed that the gas-slag-metal equilibrium consideration is able to qualitatively analyze the transfer behaviors involved in the submerged arc welding system, even under high temperatures. Based on the quantitative data, the practical implications as well as limitations of the gas-slag-metal equilibrium model are proposed. [ABSTRACT FROM AUTHOR]

The research paper was prepared within the framework of a project whose aim is to improve the durability of the corrosion protection properties of the product by regulating the input parameters of the cross-wire welding process. Cross-wire welding is a subtype of electric resistance welding. Products made by the cross-wire welding process are widely used in everyday life and can be found in the form of grids, gratings, fencing systems, baskets, guards, etc. The subject of the research work is a preliminary analysis of the stability of the cross-wire welding process. The results of the performed analysis will serve as a starting point for the second phase of the project. Since the recorded values of the set down output parameter differ significantly from the expected values, this parameter is considered as an indicator of the process stability. From the specific trend of the results in the performed analysis, it was concluded that the position of the electrode has a significant influence on the result, which was confirmed by comparing the test results before and after the preliminary tests.

The welding process and the properties of welding instruments may improve the mechanical performance of an item. One of these properties is the length of the welding tool. This approach has a substantial effect on the mechanical strength of the metallic matrix. The current study used molecular dynamics modeling and LAMMPS software to evaluate the effect of welding tool length on the mechanical properties of a welded Cu–Ag metallic matrix. This simulation makes use of the Lennard-Jones potential function and the embedded atom model. First, the equilibrium phase of modeled samples was verified by changing the computation of kinetic and total energies. Next, the mechanical properties of the welded matrix were studied using the stated Young's modulus and ultimate strength. The stress-strain curve of samples demonstrated that the mechanical strength of atomic samples increased as the length of the welding tool (penetration depth) increased. Numerically, by increasing the tool penetration depth of Fe tools from 2 Å to 8 Å, Young's modulus and ultimate strength of the matrixes sample increase from 34.360 GPa to 1390.84 MPa to 38.44 GPa and 1510 MPa, respectively. This suggested that the length of the Fe welding tool significantly affected the mechanical properties of the welded metallic matrix. The longer the length of Fe welding tools, the more particles were involved, and consequently, more bonds were formed among the particles. Bonding among the particles caused changes in mechanical properties, such as greater ultimate strength. This method can optimize mechanical structures and be useful in various industries. [Display omitted] • Effect of welding tool length on mechanical properties of the welded Cu–Ag metallic matrix was investigated. • Using molecular dynamics simulation and LAMMPS software. • By increasing the tool penetration depth, Young's modulus and ultimate strength increase. • Bonding between particles causes changes in mechanical properties, such as greater ultimate strength. • This method can optimize mechanical structures and be useful in various industries. [ABSTRACT FROM AUTHOR]