Gas Welding AluminiumGas welding is still used to weld aluminium and aluminium alloys today but much less frequently than in the past having been largely superceded by TIG and MIG processes. When gas welding aluminium acetylene is the usual fuel gas and a soft neutral flame should be used. Consumables for gas welding include the filler rods and the fluxes. Cut lengths of filler conforming to pure Al, Al-5%Mg, Al-5%Si and Al-10%Si are standard, and a flux must always be used to remove the tenacious surface oxide or weld fusion will be disrupted. These fluxes are very aggressive and corrosive and must be thoroughly washed off once welding is complete. It is normal to try to use a filler material that is as close to the parent material as possible. It is important to be aware that some aluminium alloy compositions tend to crack if welded without filler. The main problems encountered during gas welding of aluminium are porosity and oxide inclusions. These can be controlled by use of correct technique. Solidification or liquation cracking may also occur in sensitive alloys. The main potential safety hazards are fire, explosion, and corrosive fluxes. Welding fume generation is normally low.
|
