Production Of Magnesium and Magnesium Alloys Strip
Magnesium and its alloys are recognized as ‘wonder materials’ because of their performance in terms of lightness, strength and heat resistance compared to other metals. This feature makes magnesium and its alloys an attractive choice for the production of strip, which is commonly used in various applications, such as in the aerospace and automotive industries as well as in electrical applications.
The production of magnesium and its alloys into strip involves similar forming processes as used for other metals. This includes the process steps of cutting, hot rolled and cold rolling, annealing and pickling.
Initially, preferably large stock coils of magnesium and its alloys are provided as they impart strenght and stability. The coils are then cut into smaller sizes as needed in order to process them easily. The cutting process typically involves shearing or sawing and mechanical hold-downs or strips made of urethane or rubber. Then the cut strips are subjected to hot rolling to reduce their cross-section by passing them through two counter-rotating rolls. The hot rolling parameters are selected in such a way that the magnesium strips are heated to the appropriate temperature and rolled to the required thickness with minimal change in shape.
After hot rolling, the strips are annealed in order to refinish, homogenize and reduce the mechanical properties. This consists of heating the strip at an appropriate temperature for a specified holding time and cooling it at an optiomal cooling rate. The annealing parameter is determined relative to the chosen alloy in order to achieve the desired physical properties. This process is usually repeated several times and followed by pickling.
The pickling process aids in the corrosion resistance of the strip. It is typically done after a strip is cold rolled and annealed. This involves passing the strip in an acid bath solution in order to remove scale, oxide, and other impurities. This is achieved by the reaction of the solution with the surfaces of the strip leading to the generation of an oxide film on the strip’s surface. This oxide film further helps in protecting the strip from corroding.
Finally, the strip may also be coated with a protective coating such as paint or lacquer in order to protect it from elements, including moisture, which could cause damage.
The production of strip from magnesium and its alloys requires consideration for the optimum processing parameters for each alloy and is a key factor when manufacturing strip for various applications. In addition to removing impurities and providing adequate protection to the strip, the production process must be properly managed in order to ensure the optimal performance of the final product.
