Aluminum Welding 101

Aluminum is a widely-used welding material due to its impressive strength-to-weight ratio and wide range of uses. However, like all metals, aluminum poses its own challenges when welding.

Burnthrough and lack of fusion on thinner sections can be serious issues, as can porosity. Being aware of these potential issues will enable you to work safely and efficiently with aluminum.
Welding Procedures

Welding aluminum is a complex task that necessitates meticulous preparation and advanced skill. This includes selecting the appropriate equipment, setting welding parameters correctly and understanding aluminum's unique properties.

Arc welding is the go-to welding technique for industrial aluminum fabrication. This method involves applying power to melt and join aluminum sheets, with applications such as boat building, gates and fencing.

MIG welding is often employed in industrial settings and it's considered the faster way to weld aluminum. This semi-automated procedure employing a spool gun works best with thicker metals.

Prior to welding, it's essential to keep the aluminum base and filler rod clean. Without this step, an oxide layer may impede weld formation for a strong and secure joint.

Another challenge when welding aluminum is porosity, which occurs when hydrogen enters the weld pool during melting and becomes trapped within it. This can create a discontinuity in the weld, leading to weaker joints overall.


Equipment

Acquiring the appropriate equipment is key to aluminum welding success. A quality gun and wire feeding system, for instance, will enhance your welds.

Selecting the proper shielding gas for aluminum welding is essential. Depending on your aluminum base metal's thickness and any issues encountered, you'll want to select a shielding gas that best meets your requirements.

Welding aluminum can be challenging due to its high thermal conductivity and low melting point. This makes it vulnerable to burnthrough, which in turn leads to weld defects like cracking or porosity.
Safety

Welding aluminium can be a hazardous activity that could result in burns, blisters and eye damage if not done correctly. To safeguard yourself, always wear a welding helmet, protective welding jacket, gloves, boots and aprons when welding aluminium.

Maintain the base metal: To do this, gently scrape away aluminum oxide using a stainless steel brush. Doing this is important because this layer melts at higher temperatures than the base material and absorbs moisture which could cause porosity.

When possible, opt for domestic aluminum melt source material as it typically contains fewer impurities and offers better weld quality at a much cheaper cost.

Avoid Stress Cracking: Stress cracking can occur when a hot weld cools due to excessive shrinkage stresses, such as those encountered when welding concave bead profiles or at slow travel speeds. Preheating and using filler metal containing silicon can help mitigate this issue.

Ozone is a common component of welding fumes when working with aluminum, so it's essential to use an effective fume extractor that can remove chemicals at their source to minimize health risks.
Materials

Aluminum is a widely-used metal in industrial and transportation applications due to its superior strength-to-weight ratio and corrosion resistance. Furthermore, aluminum has excellent electrical and thermal conductivities.

When welding aluminum, it is essential to select the appropriate materials for each job. Doing so will guarantee a strong and dependable weld.

For optimal results, select a metal that has similar melting range as your base material. This will help narrow down the melting range and make welding much simpler.

Another way to enhance your weld quality is by using a filler metal with low shrinkage rate, like silicon. This reduces shrinkage stresses in areas that are more prone to cracking.

In addition to the base material, you must ensure any filler metals you use are clean. They could be contaminated by surface oxides, leading to porosity and cracking issues.

Source: Metalwebnews.com

Aluminum Welding 101