Automotive aluminum alloy

Automotive aluminum alloy

1. Typical production process and performance control of automobile body aluminum sheet

Under the global situation of advocating energy conservation and environmental protection, the application of lightweight technology in the automotive industry has been pushed onto the agenda. The application of aluminum alloy sheets for automotive panels is a simple and effective way to reduce weight. Automotive aluminum panels are among the high-end aluminum alloy varieties One type, due to its strict requirements for performance (forming, connection, etc.) and surface quality, it also puts forward more refined control and management requirements for the processing of raw materials.

The production process of automobile aluminum sheet is shown. The aluminum liquid is continuously cast into aluminum billets of different specifications, after surface treatment, heating, hot rolling, coiling, and cold rolling are performed to obtain the required thickness, and then continuous annealing heat treatment is performed to obtain the desired thickness. The required microscopic fine structure and performance.

There are many key technologies and difficulties in the production of automotive aluminum sheet materials, which will also have an important impact on the subsequent performance (stamping, coating, etc.).

Looking at the production process of automobile aluminum sheets, from the perspective of microstructure, it can be simply summarized into two aspects: cleanliness (chemical metallurgical process) and uniformity (physical metallurgical process). Reflected in the actual mass production process is the smelting (casting) And the control process of rolling (heat treatment). Excellent aluminum liquid cleanliness and organization (texture) uniformity have a positive effect on the stamping and connection performance of subsequent automobile production plants. Organization (texture) uniformity , Including the size of the grain size of the matrix structure and the proportion of micro-textures that are conducive to formability. The macro-external performance of the material performance is based on its micro-internal essence. Reasonable control of the micro-structure and texture, The required macro performance can be obtained.

In view of the mismatch between the production time of the raw material aluminum factory and the automobile factory, the natural aging of the automobile aluminum plate will occur during the interphase process, which affects the subsequent molding. In order to solve this problem, domestic and foreign material engineers have carried out an in-depth system of the theoretical mechanism of the process The research puts forward the pre-ageing/pre-straining treatment process. Through the pre-ageing process after the solution treatment of the raw material factory, the natural aging problem during the transportation and storage of the plate can be slowed down, so that it has better formability in the stamping process.

The reasonable treatment of the surface of the aluminum plate is conducive to the subsequent coating treatment. The surface treatment is mainly to treat the cold rolled state, which is divided into smooth surface (Mill Finish, MF), electric spark passivation (Electron Discharge Texture, EDT) and electronic Beam passivation (Electron Beam Texture, EBT) processing.

2. Process equipment for body aluminum panels

The core technology of automobile aluminum plate production is continuous annealing heat treatment and surface treatment, heating furnace, hot rolling mill, coiler, cold rolling mill and air-cushion continuous heat treatment furnace. The hot rolling mill of modern production line generally includes a reversible billet rolling mill and a Following the high-speed finishing mills, cold rolling mills are generally single-stand reversible. The melting, hot rolling and cold rolling processes are not significantly different from the conventional aluminum plate production process, so there are no special requirements for the corresponding equipment.

The air cushion furnace selected for the continuous annealing heat treatment process, the equipment mainly includes an uncoiler, a degreasing box, a drying box, a heating zone, a cooling zone, a coiler, etc.The static and dynamic airflow in the furnace supports the plate and strip like a mat and realizes Heating or cooling. The aluminum plate floats steadily at a certain height in the furnace, and the speed of the airflow is used to ensure high-speed heat exchange with the aluminum plate. By controlling the running speed of the aluminum plate in the furnace, the tension and the furnace pressure, To realize the solution treatment process of aluminum plate.