PSI - Issue 59

D. Nosov et al. / Procedia Structural Integrity 59 (2024) 656–663

657

2

D. Nosov et al. / Structural Integrity Procedia 00 (2019) 000 – 000

relative strength type of destruction

RS TD

1. Introduction Band saw welding is a process used to join the ends of a new or broken (worn) band saw blade to create a continuous loop. Band saw welding is complex and requires a responsible approach to the process. The operator must have sufficient knowledge and skills in the field of welding, as well as follow the established rules (Peremitko et al., 2014). Namely, strictly comply with the requirements for parallelism and flatness of parts during assembly and during welding. Flatness of surfaces is critical. Even small deviations can lead to uneven pressure distribution during welding and unsatisfactory quality of the joint. To ensure proper flatness, it is necessary to position the welding parts correctly. The use of supports and clamps can help to avoid improper deviations during the welding process, but leads to an increase in the time at the preparatory stage and reduces the manufacturability of the process. When choosing a welding machine, it is necessary to pay attention to its power and the accuracy of adjusting the welding parameters. For example, welding of a thin sheet requires an apparatus with precise current regulation and heat treatment, but such apparatuses are much more expensive than those with a limited set of mode adjustments. Welding process parameters such as temperature, welding speed and pressure must be well balanced. Too high temperature can lead to overheating of the blade, which will affect its properties, and too low temperature can lead to insufficient of weld’s strength. The welding speed should also be fast enough to prevent the blade from overheating, but not too fast to allow the material to melt. After welding, it is important to perform heat treatment to ensure optimum weld strength and prevent blade damage. All these factors are interrelated and require a careful integrated approach to the band saw welding process. If the welding process is performed correctly, it will provide the necessary strength and duration of operation (Peremitko et al., 2022). The purpose of the research and experimental verification of the defined problems will be the development and optimization of technological parameters of butt contact welding for the production of band saws made of 65G steel to ensure uniform strength of welded joints. This involves establishing optimal welding parameters, determining the effect of various variables on the quality of the weld (for example, current, welding time), and identifying possible methods of increasing the strength of the joints, such as the use of additional fasteners or post-weld heat treatment. It is assumed that the results of the research will allow determining the optimal practical recommendations for welding band saws made of 65G steel, ensuring the reliability and duration of their operation. 2. Theory It is known from open sources that at a minimum (Peremitko et al., 2021), the welding machine that is used in the manufacturing process of the saw must have adjustable welding parameters, such as welding current and time, to provide optimal settings for the specific material of the blade. Most practitioners (Hamedi et al., 2017, Zhang et al., 2019) pay attention to the significant influence of the preparatory stage on the quality of the welded joint, namely: before welding, the ends of the sheet should be thoroughly cleaned to remove dirt, oil, which can affect the quality of the weld; the ends of the canvas must be aligned and have constant minimum gaps during assembly; deplaning of the canvas is not acceptable. In order to achieve uniform strength of welded joints obtained by butt contact welding in the manufacture of band saws made of 65G steel, it is important to choose appropriate materials, observe optimal welding parameters and control the accuracy of alignment of the workpieces before welding. In addition, excessive heating should be avoided, deformation should be prevented, and the quality of welded joints should be regularly monitored by visual inspection and non-destructive testing methods (Zhang et al., 2020). After welding, the sheets should be annealed to relieve internal stresses and improve the quality of the weld. This is usually done by heating the canvas to a certain temperature, then slowly cooling it.