Iron and aluminum alloys cannot be welded together.
Aluminum alloy parts and iron parts can be combined by riveting, bonding and bolting.
Reasons why iron and aluminum alloys cannot be welded
When aluminum and iron are melted together, they form an extremely brittle melting zone that lacks sufficient mechanical strength and toughness, making it impractical for use in welding.
However, by using brazing, neither aluminum nor iron will melt, and only the brazing material will melt.
It is evident that the two can be joined together, but the operating conditions and brazing materials can be difficult to manage.
Braze
The method of connecting weldments involves using metal materials with a lower melting point than the base metal as solder. The process includes heating the weldment and solder to a temperature higher than the melting point of the solder but lower than the melting temperature of the base metal. This causes the base metal to be wetted by the liquid solder, filling the joint gap, and diffusing with the base metal to create the connection.
Brazing has the advantage of producing small deformation and a smooth and attractive joint. It is suitable for welding precise, complex, and components composed of different materials, such as honeycomb structural plates, turbine blades, cemented carbide cutters, and printed circuit boards.
Before brazing, it is necessary to carefully process and clean the workpiece to remove oil stains and excessive oxide film, ensuring the assembly gap of the interface. The clearance between the components should typically be between 0.01 and 0.1 mm.
Brazing application features
- Brazing has several advantages, including low heating temperature, producing smooth and flat joints with minimal changes in microstructure and mechanical properties. It also results in small deformation and accurate workpiece size.
- Furthermore, brazing can weld different metals and materials without strict limits on the thickness difference of the workpiece. Some brazing methods can even weld multiple weldments and joints simultaneously, making it highly productive.
- Brazing equipment is simple and requires low production investment. However, it has some limitations. The joint has low strength and poor heat resistance, requiring strict cleaning requirements before welding. Additionally, the solder used for brazing can be expensive.
