7020 aluminum alloy is a medium-high strength Al-Zn-Mg alloy with high strength, good welding performance and process performance. It is the main welding structural material for aerospace vehicles and ground vehicles and equipment.
7020 aluminum plate sheet is widely used in the manufacture of high-speed trains. Bodywork materials. During the service life of the alloy, the alloy has been exposed to cyclic alternating stress environments such as load, acceleration, and deceleration for a long time. It not only requires good mechanical properties and corrosion properties, but also requires high fatigue properties. At present, China's high-speed railway and high-speed train technology research is in the rapid development stage. High-speed trains such as sleeper beams, traction beams and other profiles are one of the most important load-bearing components of high-speed trains. Fatigue failure after long-term service will seriously affect high-speed trains. Trains run safely.
7020 aluminum plate sheet has good comprehensive properties after heat treatment, but the alloy is sensitive to stress corrosion cracking (SCC), and its application potential has been limited. SCC of aluminum alloys can only occur in humid hydrogen or water vapor. Grain cracking is an important feature of hydrogen-induced cracking of aluminum alloys.
The tensile strength and yield strength of
7020 aluminum plate sheet are 404 and 352 MPa, respectively, and the elongation is 17.9%. The tensile strength and yield strength of the friction stir welding parts were 352 and 223 MPa, respectively, the elongation was 9.8%, and the welding coefficient was 86.9%.
