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In this paper, a metaheuristic optimized multilayer feed‐forward artificial neural network (ANN) controller is proposed to extract the maximum power from available solar energy for a three-phase shunt active power filter (APF) grid connected photovoltaic (PV) system supplying an arc welding machine. Firstly, in order to improve the maximum power point (MPP) delivered by PV arrays and to overcome the drawbacks in the conventional MPPT method under irradiation variation, a hybrid MPPT controller is designed, in which the input parameters include the PV array voltage and current, and the output parameter is the duty cycle of the DC/DC boost converter. The proposed approach abbreviated as ANN-ACO MPPT controller is based on an ant colony optimization (ACO) algorithm which is useful to train the developed ANN and to evolve the connection weights and biases to get the optimal values of duty cycle converter corresponding to the MPP of a PV array. Secondly, aiming to meet the various grid requirements such as power quality improvement, distortion free signals etc., a three-phase shunt APF is utilized, and a direct power control algorithm is designed for distributing the solar energy between the DC-link capacitor, arc welding machine and the AC grid. Finally, the performance of proposed control system is confirmed by simulation tests on a 12.2 kW PV system. Both simulation and experimental results have demonstrated that the deigned ANN-ACO MPPT controller can provide a better MPP tracking with a faster speed and a high robustness with a minimal steady-state oscillation than those obtained with the conventional INC method. Also, with the use of a three-phase shunt APF, all the power fluctuations from the arc welding machine disturbances are damped out and the output active and reactive power become controllable.

The paper presents a study on the influence of welding parameters that is done by radiographic interpretation of the X-ray analysis results collected from welded joins that had been realized by varying the welding current intensity, tension and welding speed. The base material of the experiment is a pressure vessel steel P355 N used for constructing railway tanks for transporting liquids by train. The welding method used is flux-cored arc welding, done by a semi-automatic welding machine using welding wire as joining material. The research aims to find connections between different material welding defects and the welding parameters involved in the process of flux-cored arc welding.

The test uses a resistance welding machine to implement resistance spot welding of 6061-T6 aluminum alloy thin plate for automobile body and obtains the welding process parameters of resistance spot welding through the test. Using an orthogonal test scheme and extreme difference analysis method to test and further optimize the resistance welding process parameters, after lap resistance spot welding of a 6061-T6 aluminum alloy thin plate with a thickness of 2 mm, we analyze the welding appearance and complete the tensile test. The test results show that when the welding current is 60 KA, the welding pressure is 0.63 MPa, the thickness of the plate is 2.00 mm, the spot weld joints obtained from the specimen have no obvious defects, better molding, good welding quality and appearance, and its tensile shear value is 5.583 KN at maximum.

Wire and arc additive manufacturing (WAAM) is a novel rapid prototyping process that employs gas tungsten arc welding, controlled by a robot, to build complex 3D parts by successive layer deposition technique. Experimental studies on WAAM are useful for understanding the physics of the process however the quantification and optimization of process parameters is difficult due to complex mechanisms involved in WAAM process. In this present work, the measurement of two bead dimensions (bead height and bead width) based on the three inputs (peak current, wire feed speed, and travel speed) is done using the gas tungsten arc welding machine. Experimental study is followed by proposition of two variants of advanced evolutionary algorithms (gene expression programming and multi-gene genetic programming) in formulation of the functional expressions for the two bead dimensions based on the three inputs. The performance analysis of the two proposed models is conducted based on the four statistical error metrics, hypothesis tests and cross-validation. The relationships extracted between the bead dimensions and the three inputs reveals that the peak current influences both the bead height and bead width simultaneously. The findings reported will have a positive implication on the industry in predictive monitoring of the bead dimensions during the WAAM process.

The paper is devoted to analysis of power losses in a resistance welding machine including supplying system and examination of welding conditions of the welding machine current in a case of synchronous (simultaneous) operation of multiple welding machines, i.e., during the conduction of welding current. Analysis of the most important contributors of power losses generated on the current path between a power source and the welded joint is carried out. The analysis is carried out for a DC (direct current) welding machine with power electronics inverter. AC (alternating current) welding machines are also taken into account. The analysis is divided in two parts. The first one is the analysis of single welding machine operation, while in the second part, coexistence (mutual operation) of two synchronous welding machines is considered. The analysis is based on results of numerical and experimental investigations. The first one is focused on calculation of power losses in the energy path (including a Sankey type power loss distribution diagrams), and the second one is based on experimental tests carried out to determine the diameter of the weld nugget and the strength of the joints, for cases of reducing the welding current. An example of simultaneous operation of welding machines was presented and discussed. The percentage voltage drops and power losses in the entire power supply path of the resistance welder are shown. The analysis carried out is extremely important from this point quality of welded joints.

The European standard ISO 3690 regulates the measurement of diffusible hydrogen in arc-welded metal. It was designed for different welding methods performed in dry atmosphere (20% humidity). Some details of the standard are not applicable for wet underwater welding. The objective of this study was to extend the applicability of DIN EN ISO 3690:2018-12 to underwater wet-shielded metal arc welding (SMAW). Four different aspects regulated within the standard were accounted for: (1) sample dimensions and number of samples taken simultaneously; (2) time limitations defined by the standard regarding the welding and the cleaning process; (3) time, temperature, and method defined for analysis of the diffusible hydrogen content; (4) normalization of the hydrogen concentration measured. Underwater wet welding was performed using an automated, arc voltage-controlled welding machine. The results are discussed in light of standard DIN EN ISO 3690, and recommendations are provided for the analysis of diffusible hydrogen content upon underwater wet welding.

With the growing energy demand both domestically and internationally, significant progress has been made in the construction of long-distance oil and gas pipelines and the maintenance of in-service pipelines, which has simultaneously raised higher requirements for automatic welding equipment, process methods, and efficiency. In recent years, automatic welding equipment used for oil and gas pipeline welding has predominantly employed arc-tracking technology, which meets the requirements for fully automatic fill and cap welding in standard groove configurations with stable welding quality. However, in hot-work welding processes for in-service pipeline maintenance and emergency repairs, manual alignment and cutting result in irregular weld seams, leading to poor performance of automatic welding equipment and, consequently, reliance on manual welding, which is inefficient. To address this, a specialized automatic welding machine with a laser vision weld seam tracking system was designed for welding irregular weld seams in long-distance oil and gas pipelines. Research was conducted on its mechanical system, control system, welding system, and tracking process. The specialized machine primarily consists of a power supply box, control box, industrial computer, laser sensing system, and welding carriage. During welding, the laser sensor measures three-dimensional information such as the seam size and center offset in real time along the direction of the welding carriage movement and feeds it back to the controller through the communication system of the machine. The main control system receives the information and adjusts the welding torch’s movement and welding process parameters through internal tracking control algorithms. Welding experiments were conducted on X80 steel V-groove welds of long-distance oil and gas pipelines. The results show that the welding machine can accurately identify the weld seam width, center offset, and height offset, and adjust the welding torch actions and parameters accordingly, achieving fully automated adaptive tracking welding. The precision of single torch oscillation tracking during welding can reach 0.5 mm, and the welding quality is good, meeting the requirements for single-layer single-pass fill welding, and multi-pass welding of irregular pipeline weld seams.

The gas tungsten arc welding (GTAW) is a primary method for nuclear component fabrication and repair. Recent advancements in monitoring and automation technologies have made the shift toward fully automated arc welding more feasible, reducing the necessity for continuous human oversight. Two artificial intelligence-based networks were developed that utilize sensor-based feedback on a mechanized GTAW head. We present an image-based semantic segmentation convolutional neural network that identifies crucial features such as the weld pool, groove, wire, and electrode based on which geometric measurements are derived. A separate novel neural network predicts the weld bead geometry for multi-pass welds and inconsistent groove geometries. The application of both neural networks is a pre-requisite that enables the autonomous planning and execution of multi-pass welds to fill a groove.

This work aims to establish a suitable numerical simulation model for hybrid laser-electric arc heat source welding of dissimilar Mg alloys between AZ31 and AZ80. Based on the energy conservation law and Fourier’s law of heat conduction, the differential equations of the three-dimensional temperature field for nonlinear transient heat conduction are built. According to the analysis of nonlinear transient heat transfer, the equations representing initial conditions and boundary conditions are obtained. The “double ellipsoidal heat source + 3D Gaussian heat source” combination was chosen to construct the laser-electric arc hybrid heat source. The weld bead morphologies and the distribution of temperature, stress, displacement and plastic strains are numerically simulated. The actual welding experiments were performed by a hybrid laser-electric arc welding machine. The interaction mechanism between laser and electric arc in the hybrid welding of Mg alloys is discussed in detail. The hybrid heat source can promote the absorption of laser energy and electric arc in the molten pool, resulting in more uniform energy distribution in the molten pool and the corresponding improvement of welding parameters. This work can provide theoretical guidance and data supports for the optimization of the hybrid laser-electric arc welding processes for Mg alloys.

In the industrial production of pressure vessels (PV), a very important role is played by the welding of the elements that make up the vessel. The predominant welding technology in the case of manufacturing PV is the submerged arc welding (SAW) for which different welding regimes are defined depending on the characteristics of the base material. The welding regimes are made up of various parameters easy to manipulate by the operators of the welding machines, one of them is the welding angle. In this article, aspects are discussed regarding the way in which the welding angle of SAW influences the quality of welded joints. Tensile tests were carried out on specimens taken from plates joined by SAW using different values of the electrode tilt. Aspects regarding the geometry and dimensions of the welded joints obtained as a result of the variation of the welding angle are analysed and, in the end, an optimal angle is indicated for the welding process of PV. The basic material used in the experiments is a fine-grained material intended for the manufacture of vessels that work in high pressure and high temperature regimes, named in the technical literature P355 N.