Technique in aluminum welding

Aluminum metal has high thermal conductivity and low melting point, which can easily lead to “burning” when soldering, if the welder does not know the right type of welding machine and follow the process. To overcome that, we will share some of the experience here. Read and consult!

Prepare welding materials

First, to weld aluminum you need to clean the surface of the solder carefully. Wipe off surface aluminum oxide, oil, grease. Aluminum oxide on the solder surface melts at 3700 degrees Fahrenheit while the aluminum material of the solder parts has a melting temperature of less than 1200 F. Therefore, the cleaning of the oxide on the welding surface will limit the penetration of the solder. The depth of the metal to the weld.

Note, you do not use brushes used with steel or stainless steel welds to clean the aluminum solder. When using chemical solutions, be sure to clean the corrosive solvent on the surface before welding. To minimize the risk of hydrocarbon from grease or solvents from entering the weld, clean them with a detergent. You need to check to make sure the ingredients in the bleach does not contain hydrocarbons.

Preheat heating

Heat preheat welding to prevent cracking. The welding heat temperature should not exceed 230F. Should use thermometers to actively maintain heat, avoid overheating. Welder also needs to heat the thick parts before welding with thin parts.

Using the technology to push the torch

Welding is an extremely important part of electronic welding. With aluminum alloy, welding with welding instead of pulling the mine to clean better, reduce welding contamination and increase the protection of the gas.

Movement speed

Aluminum welding needs to be done “hot and fast”. Unlike steel, the high thermal conductivity of aluminum requires the need to set the welding voltage, the greater the welding current and the faster the torch travel speed. If the speed of the beak moves slowly, it can lead to burning fires, especially thin parts.

Gas protection

Argon gas has a cleaning effect and good penetration properties, which is the most common gas with aluminum welding. Welding aluminum alloy 5XXX series, Ar + He protective gas mixture – maximum 75% He – will minimize the formation of Mg oxide.

Welding wire

Select a welded wire with a melting temperature similar to that of the base material. The less the welders limit the melting range of the metal, the easier it is to weld. To weld thin parts, a 0.8 mm wire coupled with a low speed welding process – 100 to 300 inches per minute – is optimal.

Formed convex weld

When welding aluminum, cracking occurs easily. Cracking is due to the high thermal expansion of aluminum and shrinkage can occur when the weld cools. The risk of cracking is great for concave welds because the surface of the weld is susceptible to shrinkage and tear when cooled. Consequently, the welder should use welding operations to form the convex weld. As the weld cools, the protrusion of the weld will balance the shrinkage.

Selection of welding source

When selecting an electronic welding machine to weld aluminum in the protective gas, first choose the method of arc or spray pulse. Electronic welding machines with constant-current welding mode (CC) and constant-voltage welding (CV) are commonly used for spray arc welding. With thick aluminum parts, welding currents above 350A, CC mode for best results.