Aluminum alloy plate technology is mature, lightweight effect is obvious, cost is relatively low, widely used in the body. Compared with traditional steel plate, aluminum alloy plate also has some disadvantages, which have a great influence on product structure design and manufacturing process.
1) The yield strength and tensile strength are low, the modulus of elasticity is about one third of that of steel, the strength and rigidity of parts are low, and the dent resistance is poor. In order to ensure the same performance requirements of parts, the material thickness of aluminum plate parts is generally 50% higher than that of steel plate parts.
2) The poor formability of aluminum alloy sheet metal has great restriction on the structural design of body parts. It is easy to cause necking and cracking because of the low elongation and thickness anisotropy.
3) The springback of stamping parts is serious, which challenges the parts design, stamping production and parts matching.
4) The hardness of aluminum alloy is low and its surface is easy to be scratched, which puts forward higher requirements for storage, production and logistics.
5) The stamping production line of steel parts needs to be completely reformed.
Matters needing attention and optimization measures in the application of aluminum alloy sheet in vehicle body.
(1) Selection of parts materials. The material application of body parts is mainly 5 series and 6 series aluminum alloy. 5 series aluminum alloy can form complex structural parts because of its excellent stamping formability. However, due to the problems of oblique lines and corrugations on the surface of parts which are difficult to eliminate during stamping and after baking, it can not be applied to outer plate parts. 6-series aluminum alloy can be strengthened by heat treatment, and the strength and concave resistance of parts can be significantly improved after baking in the coating workshop, which is widely used in the production of stamping parts with external surfaces.
(2) The design of the part shall combine function, performance and manufacturing feasibility. Parts shall be symmetrical and regular as much as possible; stiffeners shall be arranged as much as possible for long strip and flat parts to improve part rigidity; fillet radius and draft angle shall be increased appropriately; local structure shall be avoided to be too complex, etc.
(3) During the stamping process design, it is necessary to ensure that the first drawing is in place as much as possible to avoid the second drawing and shaping.
(4) Springback Control of stamping parts. Increase the rigidity of the parts, optimize the stamping process design, fully simulate the stamping CAE, predict and compensate the springback, and extend the debugging cycle of the die.
(5) The die structure design is optimized to avoid common defects such as cracking, wrinkling, insufficient deformation, double material, indentation, chip and waste discharge.
(6) 6 series aluminum alloy is naturally aged to ensure that the sheet can be used within 3 months after entering the factory, otherwise the stamping formability and surface quality of parts will be affected.
(7) When the steel aluminum stamping parts are produced in the same line, the stamping production line is required to have the functions of air knife splitting, waste automatic sorting and recycling, etc.
(8) Ventilation and dust removal shall be done well in repair workshop to prevent potential explosion of aluminum powder.