Asosiasi Pengelasan Indonesia (API)

There is no question that the use of aluminium is increasing  within the welding fabrication industry. Manufacturers often adopt this material either through innovation, or as a result of pressure applied by their end users. The unique characteristics of  aluminium—light weight, excellent corrosion resistance, high strength, high toughness, extreme temperature capability, versatility of extruding and recycling capabilities—make it one of the current favoured choices of material for many engineers and designers for a variety of welding fabrication applications.

Because of the increased use of aluminium as a manufacturing material, the conversion from steel to aluminium within the welding fabrication industry is becoming increasingly common. The successful conversion from steel to aluminium welding is largely dependent on an understanding of the fundamental differences between these two materials. I have selected some of the most common problems that are encountered when changing to aluminium welding, such as feedability, porosity, cracking and filler alloy selection.

Feedability
This is the ability consistently to feed the spooled welding wire when MIG welding without interruption during the welding process. Feedability is probably the most common problem when changing to the MIG welding of aluminium. Feedability is a far more signifi-cant issue for aluminium than it is for steel. This is primarily due to the difference between the mechanical properties of the material. Steel welding wire is comparatively rigged and can withstand far more mechanical abuse. Aluminium is softer, more susceptible to deformation or shaving during the feeding operation and consequently requires far more attention when selecting and setting up a feed system for MIG welding. Feedability problems often express themselves in the form of irregular wire feed or as burn-backs (the fusion of the welding wire to the inside of the contact tip). In order to prevent excessive feedability problems of this kind, it is important to understand the entire feed system and its effect on aluminium welding wire. If we start with the spool end of the feed system, we must first consider the brake settings.