Aluminum and aluminum alloys have common physical and chemical properties. Its appearance is silver-gray, the density is small, the resistivity is small, and the coefficient of linear expansion is large. Since aluminum is a face-centered cubic structure, it has no isomeric changes, no "delay-brittle" change, so it has excellent low temperature resistance and can maintain outstanding mechanical properties at low temperatures.
Aluminum and aluminum alloys are simply processed and formed. They can be used to form a variety of products by casting, rolling, stamping, wire drawing, pressing, drawing and rolling. Aluminum and aluminum alloys are simple to machine and process fast, which is one of the important factors in the use of aluminum parts. Aluminum has a wide range of mechanical, electrochemical, chemical or paint finishes.
The production process of aluminum alloy wire is: casting - suede - kneading - drawing (repeated) - annealing (repeated) - oil seal (or appearance brightening) - packaging. There are two kinds of supply methods for aluminum alloy welding wire: (1) in semi-hard condition, supplied with external oil seal, pickled before welding; (2) supplied in semi-hard condition, bright appearance, no need to pickle before welding.
It is necessary to pickle the aluminum alloy wire before welding to remove the surface oil and oxide film. Generally suitable for hand soldering, it is difficult to ensure the quality of weld seam during active welding, and it is easy to present the defects of weld pores and welding noisy. There are many pits on the surface of the pickling wire from the microscopic view, with corrosive products, easy to absorb moisture, and the welding method can be used to remove the external pit deposits to ensure the quality of the weld. In the active welding, it is necessary to install the wire on the wire feeding arrangement of the welding machine in the form of a disk. It is very difficult to scrape the surface after pickling. The pickling wire is not recommended for active welding. Bright welding wire for hand soldering eliminates the need for pre-weld pickling and scraping, which is more convenient.
The inclusions in the aluminum alloy wire can cause noisy welds or dirt on the surface of the weld, which seriously affects the quality of the weld. Although the welding wire production specification has a low-order arrangement for inspection and control of the impurities, it is difficult to check the impurities by low-order inspection in practice. Manipulating the aluminum alloy wire and twisting materials should control the two steps of casting and wire drawing. The quality of the ingot determines the quality of the wire. The poor wire drawing process will also cause foreign objects to be wrapped in the wire to form noisy.
Existing aluminum alloy welding wire, while having many problems, fundamentally ensures the demand for existing types of welding. In order to deal with the problems existing in the current production and the satisfaction of future types of welding production needs.