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Welding processes are primarily used in engineering structural components such as ships, vehicle bodies, bridges, steel structures, containers, pipelines, reactors, etc.; they are less commonly used in components of machines subject to dynamic loads (friction welding is more often used for automobile parts). When welding steel structures, the heating and cooling processes create temperature differences within the welded parts; such uneven deformation leads to internal stresses, which are known as welding residual stresses. Welding residual stresses are the main cause of process defects such as deformation and cracking in welded parts. Welding deformation compromises shape and dimension tolerances as well as joint alignment during the manufacturing process, and it also increases the gap at the groove edges, making the manufacturing process more difficult. Welding residual stresses can cause the weld seam, especially the tack welds, to break partially or completely. Residual stresses released during machining can also lead to unacceptable deformation of the workpiece. At the same time, welding residual stresses can cause brittle fracture of the structure; tensile residual stresses reduce fatigue strength and corrosion resistance, while compressive residual stresses decrease the limit of stability. Therefore, welding residual stress has always been one of the key issues of concern in the welding community. How to control welding residual stress? Welding stress is inevitable; after the welding process is completed, it causes welding deformation in the components, which helps to release some of the welding stress. The remaining stress, however, persists in the form of residual stress. In general, all welded components exhibit residual stress and deformation. We can use various methods to control welding residual stress. Design measures: (1) While ensuring the structural strength of the welded parts, stamping structures can be appropriately used to reduce the use of welded structures, thereby minimizing the number of welds as well as their cross-sectional dimensions. At the same time, the welds should not be too concentrated to prevent excessive heat input in localized areas. (2) Welds should be placed as far away as possible from the areas subject to maximum working stress, in order to prevent stress accumulation resulting from welding residual stresses and external loads, which could affect the load-bearing capacity of the component. Additionally, efforts should be made to avoid excessive concentration or intersection of welds, in order to maintain good weldability. (3) By using methods to reduce local stiffness and appropriate joint designs, the weld can contract more freely, thereby reducing stress concentration in the welded joint. (4) Adopt welding methods with low heat input and high energy density to reduce welding residual stresses, such as TIG welding and ion arc welding. Process measures: (1) During welding, start by welding the offset short welds, those with large contraction, and those under high stress first. At the same time, a corresponding welding sequence should be adopted based on the structure of the welded parts, so as to allow the welds to contract freely, minimize residual stresses within the welds, and ensure that the distribution of residual welding stresses in the parts is reasonable. (2) When welding joints with high welding restraint, care should be taken to reduce the restraint of the weld. For example, the inverse deformation method can be used to reduce the local stiffness of the welded joint, thereby decreasing the restraint stress in the weld. (3) Adopt reasonable process parameters and appropriate processing methods. If a small-diameter welding wire is used first, welding heat input can be controlled by employing a lower welding current and increasing the welding speed; methods such as preheating, heating the stress-relief zone, and hammering can also be used to reduce the residual welding stresses in the weld. (4) Digital simulation: By using the “multi-process continuous simulation software” independently developed by Xiangbo, it is possible to conduct continuous simulation of the processing workflow for workpieces. When simulating the welding process, it is sufficient to select the appropriate welding process and method, input the heat source, temperature, and other typical process parameters. By comparing results using the DOE sample method, the optimal welding sequence and parameters that result in the lowest levels of residual stress and deformation can be identified. Examples of weld analysis, elimination of welding residual stresses. The formation process of welding residual stresses is very complex and its negative effects outweigh the positive ones; therefore, it is essential to take effective measures to reduce these residual stresses. Currently, common methods for eliminating residual welding stresses include shot peening, laser treatment, loading, explosive treatment, heat treatment, hammering, vibration treatment, cryogenic treatment, ultrasonic treatment, and others. Shot peening is a process in which a stream of high-speed projectiles is directed at the surface of a component, causing plastic deformation in that surface layer and thereby creating a strengthened layer of a certain thickness. A higher residual stress is generated within the reinforcement layer; due to the compressive stress on the surface of the component, this stress can offset part of the tensile stress when the component is under load, thereby enhancing its fatigue strength. Advantages and disadvantages: The shot blasting process alters the microstructural pattern of the material’s surface; the surface that has been blasted becomes rougher and its dimensions increase. Laser treatment: This method involves using a strong pulsed laser to impact the welded joint; the plasma shock wave generated as a result can cause plastic deformation in the welding area, thereby eliminating residual welding stresses. This method can achieve stress relief of complex welded parts by precisely controlling the laser energy, impact area, impact angle, and number of impacts. Advantages and disadvantages: The laser treatment method does not damage the surface of the specimen, causes no environmental pollution, and is flexible and efficient. Proper use of lasers to treat the welding area can also increase the strength and fatigue life of the welded parts. However, if not handled properly, such as when the laser does not cover the entire welding area, it will result in poor improvement in fatigue performance. The loading method is divided into mechanical tensioning and temperature difference tensioning; it involves applying tensile stress to the welded joint in order to counteract the stresses generated during welding, thereby eliminating residual stresses. Advantages and disadvantages: Studies have shown that for austenitic stainless steels, using mechanical overload stretching can effectively reduce the peak values of welding residual stresses and make the distribution of these residual stresses more uniform. The higher the load applied, the more of the welding residual stress is eliminated. However, beyond a certain value, the effect of residual stress elimination gradually diminishes. The effect of the loading method in eliminating residual welding stresses is relatively poor; improper loading can also cause deformation of the structure. Moreover, the temperature difference stretching treatment is costly and difficult to carry out. Explosive treatment: This method involves applying a special material over the weld and the surfaces surrounding it; the shock wave generated by the explosion causes plastic deformation in the welded part, which counteracts the existing residual stresses thereby achieving elimination of those stresses. Advantages and disadvantages: During explosion treatment, improper **dosage or** unsuitable arrangement can lead to adverse consequences such as macroscopic deformation of the welded parts, insufficient removal of defects, and even casualties. Heat treatment is the primary method for eliminating residual welding stresses after welding. It involves heating the welded component as a whole or in certain areas to a temperature above the recrystallization point at a specific rate, and then holding it at that temperature for a certain period of time. During this process, the regions under tensile stress in the component are stretched, while those under compressive stress are compressed, allowing some or all of the deformations to return to their original state, thereby eliminating the residual welding stresses. Advantages and disadvantages: The post-weld heat treatment is costly, inconvenient to carry out, does not significantly improve the fatigue performance of the welded parts, and may cause reheat embrittlement and reheat cracks in those parts. Hamming treatment: Hamming treatment refers to striking the welded area with a hammer in order to induce plastic deformation in that area, thereby reducing the residual stresses resulting from welding. Common forms of hammering include: manual hammering, electric hammering, pneumatic welding-time hammering, impact gun hammering, and electromagnetic welding-time hammering. Advantages and disadvantages: The hammering treatment method features low cost, simple operation, and energy efficiency. The hammering treatment method can not only eliminate residual welding stresses, but also reshape the weld, improving the fatigue resistance and mechanical properties of the welded parts. However, if the hammering is not done properly, it may lead to a reduction in the material’s corrosion resistance, the formation of small cracks, and strain-induced aging fragility. Vibration treatment method: The vibration treatment method involves using vibrations to cause localized yielding in various parts of the welded joint under the combined effect of alternating stresses and residual stresses, thereby inducing slight plastic deformation and reducing the residual stresses within the component. Advantages and disadvantages: The vibration treatment method is simple to operate, requires little time, has low costs, and is environmentally friendly. It enables uniform distribution of stress in the welded parts, helps maintain their dimensional stability, and delays deformation. Cryogenic treatment: Cryogenic treatment involves placing the welded parts in an environment of liquid nitrogen or nitrogen vapor after quenching, and using the changes in internal stress resulting from temperature variations at different stages to offset some of the residual stresses. Advantages and disadvantages: Cryogenic treatment is pollution-free, has low costs, exerts little impact on welded parts; it can effectively maintain the dimensions of the workpieces and prevent cracking, thereby improving the mechanical properties and corrosion resistance of the welded parts. However, since the stress-relief effect is related to the cryogenic treatment process, the heat treatment processes before and after cryogenic treatment, as well as other related processes, the stability of the cryogenic treatment method is relatively poor. Cryogenic treatment is only suitable for processing small components, such as gears, cutting tools, molds, etc. Ultrasonic treatment: This method involves using ultrasonic waves to impact the welded joint, thereby causing plastic deformation in that area and eliminating residual welding stresses. Advantages and disadvantages: Compared to traditional methods, the ultrasound treatment method features low costs, ease of operation, high efficiency, as well as being environmentally friendly and energy-saving. However, the scope of application of ultrasonic treatment is limited; it is highly effective in eliminating welding residual stresses in thin-walled parts, but its effect on reducing welding residual stresses in thick plate parts is not significant. Conclusion: The residual stresses resulting from welding have more disadvantages than advantages; they not only affect the processing quality and dimensional stability of the welded parts but also reduce their performance in use. There are many methods for measuring and eliminating welding residual stresses, each with its own advantages and disadvantages. Enterprises can select the appropriate residual stress removal method based on their own needs, as well as the economic costs and operational complexity of various methods, in order to achieve the greatest economic benefits. If one does not have the capabilities to detect and eliminate residual stresses, it is also possible to turn to professional suppliers to address the issue.