According to a recently conducted survey with a welding solutions specialist, who said that the vital factor for peerless aluminum welding is “clean, clean, clean, clean… and clean”. Welding aluminum becomes pretty difficult if you are trying to weld with filthy base and filler metals incorporate excess complications and can lead to awful weld quality.

Also, you have to deal with the connatural oxidation that takes place with aluminum. Appropriate precautions are essential before welding- primarily when fabrications are a prerequisite to meet the weld quality fundamental of industry codes, such as AWS D1.2 that administers the formalistic welding of aluminum.

There are basic steps you can take in the analysis and preparation of filler and base metals to certify that you don’t face any difficulty affiliated to filth, grease and flying shop dust- along with the oxidation that occurs when aluminum is exposed to the air. We will follow these steps and present you with best precautionary methods in order to assure that you do not hinder your aluminum welding processes.

The spontaneous challenges of aluminum

Aluminum however, is less competent as compared to steel. Aluminum is more likely to develop problems like lack of fusion due to rigid oxide layer, lack of perforation due to steep thermal conductivity, and small empty spaces due to high solubility of hydrogen in smelted aluminum. Thus, all humidity and hydrocarbons must be exterminated, and compactness of the oxide layer should be monitored and safeguarded from damping due to excessive moisture.

Felicitous storage and care of Aluminum Filler and Base metals

If the oxides on aluminum TIG filler metals are introduced candidly into the weld puddle, they can cause porosity. Oxides on MIG filler metals can cause problems like an anomalous arc, amorphous carbon, excessive shielding and poor feeding.  Firm layers of oxide on aluminum base metals should be detached monotonously or face the hazard of damaging the weld. Here are a few steps that you can follow in order to avoid this from happening:

  • Avoid exposure of all welding filler metals and base metals to moisture with slightest temperature variation (to lessen condensation). Welding filler metals should be kept in an anhydrous and heated environment.
  • If possible, all the filler metals and base metals should be brought into the welding area a day before so that they can adjust to the room temperature and minimize condensation.
  • Store the aluminum pieces diagonally so that less condensation occurs and less water contamination takes place between layers.
  • Cover all the filler metals before welding. This includes a sealed case for TIG rods and a cylindrical cover for MIG wire.

Most Favorable Joint Preparation for Welding Aluminum

There are two main steps in preparing the joint for welding:

  1. Typically removing the oxide layer to make it feasible (Base metal has a lower melting point than the oxide layer)
  2. Wipe out any dirt, grease, oil, or moisture that might contaminate the weld.
  • Avoid using cutting methods that leave a slithery and an old sod exterior. Such as, a speedy circular saw for cutting aluminum instead of a band-sawed surface which might lead to smearing. Abstain from using grinders as much as possible. However, you can use a coarse disc grinder over a wheel grinder if you are left with no other option. Your aim basically should be to use a fast and sharp tool that smoothly cuts away the material. A wheel grinder can deposit pieces of stone into the aluminum so it might get contaminated. A smeared surface can cause lack of fusion so it should be filled to eradicate any smeared metal precedent to welding.
  • Avoid using oxy-fuel gas cutting, carbon arc cutting or groove processes or oxy-fuel flames to preheat. These methods destroy the heat affected region encourage the development and hydration of the oxide layer present on the surface.
  • Use scoop, plasma arc cutting and laser cutting because these methods reduce the chances of exposure of hydrogen and moisture to the oxide layer.
  • Perpetually eliminate the plasma arc and laser cut edges from 2xxx, 6xxx, 7xxx series alloys. The molten edges of these alloys comprise of unfavorable coagulation cracks and heat affected zone conditions. Discard at least 1/8-inch of metal from the prick edge. Prefer using programmed methods, such as milling or a coarse burr grinder, to snip and discard metal chips.
  • Refrain from using lubricants in aluminum cutting processes. Any petroleum-based lubricant consists of hydrocarbons, which will definitely break down during the welding process and allow hydrogen into the joint, leading to porosity and cracking.
  • Aluminum usually comes from the factory with oil and grease over it. To clean the joint before assembly, first degrease the surface with a solvent, and then use a paper towel to anhydrate the welding joint (these are favored because they are porous and soak up more oil/moisture). Along with this, wipe the diametrically opposed side of the joint clean so that none of the filth is pulled through the aluminum into the weld puddle.
  • Make sure that you use a solvent that does not leave any leftovers, and do not use chlorinated solvents in the welding area because they might form harmful gases in the presence of a welding arc.
  • Refrain from using shop rags to clean welding joints as they can conveniently transfer oil and dirt to the welding surface.
  • Avoid using compressed air to blow off the joint as it contains moisture and oil impurities.
  • Cleanse the joint with a clean wire brush, right after solvent cleaning. Wire brushing antecedent to cleaning deposits hydrocarbons and other impurities in the metal surface and also deports these unwanted elements to the brush-which makes the brush dissident for cleaning.
  • Go for a clean steel wire brush to cleanse all the metal that has been corroded. The derivatives from corrosion should be removed before welding.
  • Clean all wire brushes and cutting apparatus to counter transmission of toxins to the weld joint and, if feasible, keep dedicated brushes only for welding aluminum to reduce the chances of poisoning.