High-strength fasteners play a key role in various mechanical equipment and structures, and are of great significance for the normal operation and safety of equipment. Because high-strength fasteners bear high preload and working load, their reliability directly affects the stability and life of the entire equipment or structure. In order to improve the performance and reliability of high strength fasteners, residual stress analysis and optimal design become the key. This paper will introduce the residual stress analysis and optimal design of high strength fasteners in detail.
The material selection of high strength fasteners plays a crucial role in their performance and reliability. Common materials include steel, alloy steel, stainless steel and titanium alloy. When selecting materials, it is necessary to consider factors such as mechanical properties, fatigue resistance, corrosion resistance and cost of materials. In addition, in order to reduce residual stress, materials with good stress corrosion resistance and fatigue resistance can be selected.
The manufacturing process and flow of high strength fasteners have an important influence on the generation and distribution of residual stress. Its main process includes blanking, forming, processing, heat treatment, surface treatment and so on. In the process of machining, the residual stress and local stress concentration should be minimized. Heat treatment can improve the mechanical properties of materials, but it may also introduce new residual stresses. Surface treatments such as coatings and coatings can effectively improve corrosion resistance, but the impact on residual stress also needs to be considered.
Residual stress refers to the stress introduced by the material in the manufacturing or processing process due to non-uniform deformation, phase change and other factors. For high-strength fasteners, residual stress can lead to premature fatigue, stress corrosion cracking and other problems, thus affecting their reliability and life. Residual stress analysis can be measured and evaluated using techniques such as X-ray diffraction, ultrasound, and electron backscatter diffraction.
Based on the results of residual stress analysis, the optimal design of high strength fasteners can be carried out. Here are some of the main optimization measures:
Optimized shape design: By changing the shape of high-strength fasteners, such as rounded corners, chamfering, etc., stress concentration can be reduced, thereby reducing residual stress.
Structural optimization: By changing the structure of high-strength fasteners, such as increasing the support structure and improving the fit relationship, it can improve its stiffness and stability, so as to reduce the residual stress.
Material replacement: According to the results of residual stress analysis, materials with better residual stress characteristics, such as lower yield strength and better toughness, can be considered to improve the reliability of high-strength fasteners.
Eliminate the residual stress of heat treatment: by selecting the appropriate heat treatment process and parameters, the residual stress of heat treatment can be effectively reduced, thereby improving the reliability of high-strength fasteners.
Surface treatment optimization: According to the results of residual stress analysis, appropriate surface treatment processes and parameters can be selected, such as shot peening, laser shock strengthening, etc., to improve the surface state and residual stress status of high-strength fasteners.
Residual stress analysis and optimal design of high strength fasteners are of great significance to their performance and reliability. Through reasonable selection of materials, optimization of manufacturing process and shape design, structural optimization, material replacement and elimination of heat treatment and surface treatment residual stress and other measures, can effectively reduce the residual stress, improve the reliability of high strength fasteners. With the development of science and technology, there will be more and more effective residual stress analysis and optimal design methods in the future, providing a broader space for the development and application of high-strength fasteners.
