Test and Analysis of TIG-MIG Hybrid Welding Are

A high-speed camera is used to observe the arc starting and arc stabilization process of the TIG-MIG hybrid welding system. Paschen’s law is used to analyze the path of TIG welding arc breakdown under the condition of the conductive channel provided by the MIG welding arc, and the arc starting process of the double arc hybrid welding is determined. The study found that when the electrode spacing is less than 8.5 mm, two molten pools can form a common molten pool after arc initiation of MIG welding; when the spacing is 10 mm, the two molten pools after arc initiation form a “8” shape; When the distance is 12 mm, there is a low temperature zone between the two arcs, which is separated.

Modification of the structure and properties of hardfaced layers with TIG high frequency method

In this work the investigation is focused on changing the structure and hardness of the surface with high content of carbon and chromium. The use of welding methods to modify the properties of the surface layer allows for optimal use of the properties of materials or changing their properties by differentiate their structure. The surface and structure of hardfaced layers can be improved by additional treatment with another welding arc. The use of the new TIG methods with frequency up to 20000 Hz gives new possibility of the surfacing. The subject of the research were padding welds with the structure of chromium cast iron, which were subjected to the process of remelting the surface layer using the TIG high frequency method. The use of hardfacing and remelting with the TIG method allowed for a noticeable differentiation of the structure, hardness and wear resistance in relation to the initial state.

Modeling of welding arc power supply diagrams in Matlab / Simulink

Purpose. Creation of virtual blocks and simulation laboratory stands for the study and comprehensive research of the dynamic properties of welding power supplies. Methodology. Review of literary sources on the subject, simulation modeling of electromagnetic processes in the MATLAB software environment, comparative analysis of obtained and available data. Findings. The comparative analysis of means of modeling of power sources of a welding arc is executed. One of the main parameters by which the environments were compared is functionality. Among the considered simulators, Simulink of the MATLAB software environment is the most effective one in the considered systems modeling. Using special features, its user can not only simulate, but also analyze the operation of the over time installation. Mathematical and functional models of welding arc power supplies were built using SimPowerSystems elements and blocks from the Simulink library with the involvement of the MATLAB system itself, which significantly expands the possibilities for such systems modeling. Mathematization of certain processes to some extent shows the level of reliability of the results and the degree of their scientific development. The developed models act as a laboratory, which allows you to set and explore any modes and characteristics. Numerical experiments and comparative analysis of numerical and field experiments are given. Experimental verification of the obtained results on specific examples showed the relevance of the problem and the correctness of its solution. Further research is related to the expansion of the range of simulated power sources of the electric arc, a comprehensive study of their dynamic properties and basic characteristics, experimental verification of the developed models, as well as comparative analysis and development of recommendations for model improvement. Originality. The method of circuit modeling of general-purpose electrical and electronic circuits was further developed by extending it to a new class of objects - the power supply system of electrical installations. Practical value. Construction of mathematical and functional models of complex systems with the involvement of MATLAB allows to take into account their main features, significantly expands the possibilities for modeling, study and research of power supplies. Based on the proposed approach, simulation laboratory stands of specific power supplies were developed and built, which allow to set and study any modes and characteristics.

Comprehensive Effect of Arc and Ultrasonic Energy on MIG Arc Ultrasonic Welding

Ultrasonic energy is introduced into the Metal Inert Gas (MIG) welding arc and weld pool by superposition of an ultrasonic frequency current. In this study, the arc shape, arc energy, and ultrasonic energy that responded to ultrasonic excitation voltage and frequency is investigated. The comprehensive influence of arc and ultrasonic energy on weld formation, microstructure, and mechanical properties is further studied. The arc and ultrasonic energy are analyzed by using a high-speed camera and microphone, respectively. The results showed that the arc width increased, and the arc energy density decreased after the superposition of ultrasonic current. The arc height could be compressed under certain ultrasonic excitation parameters. The ultrasonic excitation voltage and frequency had a direct influence on the ultrasonic energy. The arc height, arc energy density, and ultrasonic energy together determined the weld width. Ultrasound could effectively refine the microstructure of the weld zone and fusion zone but had little effect on the heat-affected zone. Ultrasound improved the hardness of the joint by refining the grain and the second phase. The joint hardness was the highest when the ultrasonic excitation voltage was 100 V, and the frequency was 30 kHz.

Securing the quality of mesh weld joints in bolt support through robotized operation

Stabile strength properties of the mesh weld joints is one of the key factors in ensuring the required load-bearing capacity of the bolt support as a whole. In accordance with the basic principles of the statistical process control concept, the best quality is ensured by the production process that has the minimum variability of the results. To identify the initial parameters of the control charts used to monitor the stability of the process, the strength properties of the mesh weld joints were studied for manual, contact and robotic welding in the conditions of OKS LLC. Robotic welding is made using the ABB robotic complex consisting of three manipulators, two of which are designed to execute the movement of the welding arc and one to displace the mesh into and out of the welding zone. It is shown that the distribution of welding strength values in robotic welding is characterized with the lowest value of sample standard deviation. It was found that robotic welding was the only method among those investigated that ensured the values of additional samples to fall within the initially set range in the control charts.