Metal forgings are commonly used as basic parts in mechanical equipment, and their fatigue performance has an important impact on the stability and life of equipment. Anti-fatigue design is the key means to improve the fatigue life of metal forgings, and the life is an important index to evaluate the anti-fatigue performance of metal forgings. This paper will discuss the fatigue resistance design and life of metal forgings in detail, aiming to provide useful reference for related industries.
At home and abroad, a series of standards and specifications have been developed for the anti-fatigue design and life evaluation of metal forgings. For example, China’s GB/T 19082-2008 “Fatigue test method for Metal materials”, ASTM A370-1999 “Tensile test method for metal materials” and so on. These standards provide specific guidance and technical requirements for fatigue resistance design and life evaluation of metal forgings.
According to relevant standards and specifications, the fatigue resistance design of hardware forgings should follow the following principles:
Optimize materials: Select materials with excellent fatigue resistance, such as high-strength steel, alloy steel, etc.
Reasonable structure: Design a reasonable structure to avoid local stress concentration and overloading.
Improve the surface quality: optimize the surface treatment process, improve the surface finish, reduce the defect rate.
Reasonable selection of heat treatment process: according to the material and design requirements, choose the appropriate heat treatment process to adjust the mechanical properties and microstructure of the material.
Strengthen process control: strictly control the manufacturing process to ensure the dimensional accuracy and form and position tolerance of the parts.
Commonly used hardware forgings anti-fatigue design methods include:
Meridian contour method: By optimizing the meridian contour of the part, the stress concentration coefficient is reduced and the fatigue strength is increased.
Arc gear method: Using arc gear instead of straight gear, reduce root stress concentration, increase bending fatigue life.
Elastic element method: Add elastic elements in the area under greater stress to alleviate stress concentration and improve fatigue life.
Surface strengthening method: using shot peening, rolling and other processes to improve surface strength and enhance fatigue resistance.
Volume strengthening method: improve the overall strength and toughness of the material by optimizing the heat treatment process and organizational structure.
Taking automobile connecting rod as an example, it is a typical hardware forgings, anti-fatigue design and life evaluation are crucial to the performance and safety of automobiles. During the design process, the following factors should be considered:
Material selection: Use high-strength steel or alloy steel to ensure sufficient strength and toughness.
Structure optimization: Design reasonable connecting rod structure, avoid stress concentration, reduce bending and torsional stress.
Surface treatment: Using polishing, grinding and other processes to improve surface finish and reduce fatigue damage.
Heat treatment: According to the material and design requirements, the appropriate heat treatment process is used to adjust the mechanical properties and microstructure of the material.
Dimensional control: strictly control the dimensional accuracy and form and position tolerance of the connecting rod to avoid local stress concentration caused by assembly errors.
Through the application of the above design principles and methods, the fatigue resistance and life of automobile connecting rod can be effectively improved. At the same time, for specific application scenarios and working conditions, it is also necessary to carry out detailed fatigue analysis and life assessment to ensure that it maintains stable performance during its expected service life.
In this paper, the fatigue resistance design and life of metal forgings are discussed in detail, and the relevant standards and specifications, design principles, design methods and examples are described. Through reasonable anti-fatigue design and life evaluation, the performance and service life of metal forgings can be effectively improved, which is of great significance for the safety and stability of mechanical equipment.
