Solutions For Aluminum Alloy Welding

There are many welding methods for aluminum alloys, and each method has its own unique applications. In addition to traditional fusion welding, resistance welding, gas welding methods and other welding methods (such as plasma arc welding, electron beam welding and vacuum diffusion welding) can also be used to easily weld aluminum alloys together.

The characteristics and applications of common welding methods for aluminum alloys are shown in Table 1. Select the welding method according to the grade of aluminum and aluminum alloys, welding parts' thickness, product structure and welding requirements.

Table 1 : Characteristics and applications of common welding methods for aluminum alloys

 (1) Gas welding

The heat power of the oxygen-acetylene gas welding flame is low, resulting in more dispersed heat. This leads to large deformation of welding parts and low productivity. When welding thicker aluminum parts with gas welding, preheating is required. The weld metal after welding is not only coarse-grained and has loose tissue, but it is also prone to produce aluminum oxide inclusions, pores, and cracks. This process is only suitable for welding aluminum structure parts and castings with a thickness range of 0.5 to 10 mm.

(2) Tungsten argon arc welding

This process uses argon gas for protection during welding, the heat is more concentrated, resulting in stable arc combustion and dense weld metal, the welded joints have high strength and plasticity, making it widely used in the industry. Tungsten argon arc welding is a relatively complete welding process for aluminum alloys. However, the equipment required for this method is more complex and cannot be operated in outdoor open-air conditions.

(3) Fusion arc welding

Automatic and semi-automatic fusion arc welding has a large arc power, concentrated heat, a small heat-affected zone, and productivity that can be increased 2 to 3 times compared to manual tungsten argon arc welding. It can weld pure aluminum and aluminum alloy plates with a thickness below 50mm. For example, the welding thickness of a 30 mm aluminum plate doesn’t require preheating, and only welding positive and negative two layers can result in a smooth surface and excellent quality of the weld. Semi-automatic fusion arc welding is suitable for positioning welds, intermittent short welds and structural shape irregularities. Semi-automatic fusion arc welding torch can provide convenient and flexible welding, but semi-automatic welding wire diameter is thinner, and the weld porosity sensitivity is larger.

(4) Pulsed Arc Welding

a. Tungsten pulse arc welding: This process can significantly improve the stability of the small current welding process, it is easy to adjust various process parameters to control the arc power and weld shaping. There is a small deformation of welding parts and a small heat-affected zone, making it especially suitable for thin plates,all-position welding, assembly welding, and high-strength aluminum alloys such as forged aluminum and hard aluminum that are highly sensitive to heat.

b. Melting pulsed arc welding: The average welding current is small, and the parameter adjustment range is large. There is small deformation of the welding parts and heat-affected zone, high productivity, good porosity and cracking. It is suitable for thicknesses of 2 -10 mm aluminum alloy plates for all-position welding.

(5) Resistance spot and seam welding

It can be used to weld thin aluminum alloy plates with a thickness below 4mm. For products with high quality requirements, DC shock spot welding and seam welding can be used. Welding requires the use of more complex equipment, welding current, and high productivity, especially for mass production of parts and components.