In modern manufacturing, aluminum, thanks to its low density, high specific strength, and corrosion resistance, has become a core material across many sectors. Aluminum welding technology is crucial for joining aluminum components and directly determines product lifespan and safety. In addition to traditional hot welding, processes such as cold welding are now also being used in specific applications, but they still face challenges stemming from material properties.

Aluminum Welding: Widespread Applications Across Industries

Aerospace: Aircraft fuselages and engine compartment components rely on aluminum welding, with friction stir welding and laser welding commonly used to meet high-strength and low-deformation requirements.

New Energy Vehicles: Laser and MIG welding are primarily used for welding aluminum components such as battery trays and body frames, contributing to vehicle lightweighting.

Electronic Equipment: Micro-arc welding is used for precision aluminum parts (such as mobile phone midframes) to avoid heat damage, while cold welding can be used for repairing or joining smaller parts.

Architectural Decoration: TIG welding is commonly used for welding aluminum alloy doors and windows, as well as curtain wall keels, ensuring both aesthetics and corrosion resistance. Repair: Cold welding (resistance spot welding, ultrasonic cold welding) is used to repair small areas of wear and cracks on aluminum parts to avoid thermal deformation that could lead to scrap.

Aluminum Welding: Core Difficulties Due to Material Properties

Oxide Film Issues: Aluminum easily forms a high-melting-point aluminum oxide film, which can easily lead to weld defects when welded with hot welding. Cold welding also hinders atomic bonding and requires prior cleaning.

High Thermal Conductivity and Thermal Expansion Coefficient: Hot welding requires high input and is prone to deformation. Improper pressure control in cold welding can also cause micro-deformation.

Porosity: During hot welding, hydrogen dissolved in the molten aluminum cools and escapes, forming pores. Cold welding virtually eliminates this problem.

Alloying Element Burnout: Low-boiling-point elements are susceptible to burnout during hot welding, but cold welding completely avoids this issue, preserving the original properties of the aluminum part.

Aluminum Welding: Targeted Solutions to Core Difficulties

Oxide Film Removal: Mechanical grinding or chemical cleaning before welding; hot welding uses "cathode shattering" to destroy newly formed oxide films. Cold welding can apply an activator to enhance bonding. Deformation Control: For hot welding, use a concentrated heat input process, preheat, and use fixtures. For cold welding, adjust the pressure and time according to the aluminum part's condition, and weld in sections to distribute stress.

Porosity Prevention: Dry the material before hot welding, use high-purity inert gas shielding, and adjust parameters to extend the weld pool time. For cold welding, simply ensure surface cleanliness.

Addressing Element Burnout: For hot welding, use matching wire, short arc welding, or pulsed MIG welding. Cold welding completely avoids burnout due to the lack of high temperatures.

Aluminum Welding: Recommended Processes for Different Aluminum Alloy Types

Pure Aluminum (1 Series): Use TIG or MIG welding with ER1100 wire for hot welding. Use ultrasonic or resistance cold welding, suitable for small areas.

Duraluminum Alloys (2 Series, such as 2024): Hot welding requires a low-hydrogen process with ER4043 wire to control heat input. Cold welding can avoid thermal cracking, and requires controlled cleanliness and pressure. Rust-resistant aluminum alloys (5 series, such as 5052): Hot welding uses TIG welding or MIG welding with ER5356 wire. Cold welding is suitable for joining thin-walled, precision parts.

Forged aluminum alloys (6 series, such as 6061): Hot welding uses MIG welding or friction stir welding with ER4043/ER5356 wire. Cold welding is suitable for repairing small parts.

Specialized Cold Welding: Cold welding is preferred for heat-sensitive, high-precision aluminum parts (such as precision sensor housings). Select equipment based on the specific needs of the part and conduct trial welding and parameter adjustments.

Conclusion

Aluminum welding technology continues to innovate as demand evolves. Cold welding, as a supplementary process, offers significant advantages in precision joining and repair applications. Understanding the difficulties of aluminum welding and process adaptation strategies can improve product quality and efficiency, helping companies establish themselves in lightweight, precision manufacturing. Future developments in cold welding equipment and automated hot welding technology will drive aluminum welding towards higher precision, lower costs, and environmental friendliness.