The process of converting aluminum ore into the aluminum that we know and use every day was discovered relatively recently.
The process of converting aluminum ore into the aluminum that we know and use every day was discovered relatively recently.
Industrial production of aluminum only began in the late 19th century, making this material very much a latecomer among the common metals.
The first commercial applications of aluminum were novelty items such as mirror frames and serving trays. Cooking utensils were also a major early marketed product.
Today, aluminum’s unique characteristics of light weight, high strength, high toughness, extreme temperature capability, versatility of extruding, excellent corrosion resistance, and recycling capabilities make it the obvious choice of material by engineers and designers for a wide variety of welding fabrication applications. When we consider the advancement of aluminum within the welding fabrication industry, it becomes clear that there is a definite need for a better understanding of how to successfully weld this material.
The earliest welding techniques suitable for aluminum included oxyfuel gas welding and resistance welding. The arc welding of aluminum was restricted to shielded metal arc welding. Most of the welding processes had limitations and inherent problems, making it very challenging to produce sound welds. The breakthrough for aluminum as a structural material occurred with the introduction in the 1940s of the inert gas welding processes. First came the gas tungsten arc welding (GTAW) process, which was sometimes referred to as Heliarc and also known as the tungsten inert gas (TIG) process. This was followed shortly after by the gas metal arc welding (GMAW) process, also known as the metal inert gas (MIG) process. With the introduction of welding processes that used inert gas to protect the molten aluminum during welding, it became possible to make high-quality, high-strength welds at high speeds and in all positions without corrosive fluxes. Today, aluminum and its many alloys are readily weldable using a variety of techniques and welding processes, including newer processes such as laser beam welding and friction stir welding; however, the GTAW/TIG and GMAW/MIG processes remain the most popular — Fig. 1.Fig. 1 — A welder performs gas metal arc welding on aluminum.
The automotive industry continues to increase its use of aluminum. Environmental issues such as increased fuel efficiency are promoting more aluminum components to be used within the average automobile.
The shipbuilding industry has developed high-speed aluminum ferries (fast ferries) as a means of fast, efficient, low-maintenance transport. The advantages of aluminum are also being used for small pleasure craft, fishing boats, work boats such as coastguard vessels, and large high-speed military ships, some of which are almost exclusively manufactured from aluminum — Fig. 2.
Fig. 2 — Welders use GMAW and GTAW to fabricate a fishing boat.
The recreation and sporting equipment industry produces high-tech products through the increased use of high-strength, heat-treatable aluminum alloys such as the 7xxx series. Bicycle frames, baseball bats, golf clubs, sleds, and snowmobiles are some of the many products within this industry dependent on aluminum alloys.
The transportation and containers industry primarily uses the 5xxx series aluminum/magnesium alloys and the 6xxx series aluminum/ magnesium-silicide alloys. Large dump trucks, flatbed trailers, livestock trailers, liquid natural gas tankers, and many other types of containers are fabricated from aluminum and its alloys.
The defense and aerospace industries make use of high-strength 5xxx series nonheat-treatable alloys for some applications but also make use of some of the more specialized heat-treatable aluminum alloys with superior mechanical properties. Aluminum armor plating is used for its impact strength and strength-to-weight ratio. Perhaps the most exotic aluminum alloys, with exceptional strength over a wide range of operating temperatures, are used in the aerospace industry. These alloys are typically used in specialized high-performance applications and have their own welding characteristics and sometimes associated problems.
With the continued growth of aluminum within our industry, the American Welding Society (AWS) continues to support the industry with codes and standards such as AWS D1.2, Structural Welding Code — Aluminum, and AWS A5.10, Specification for Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods, along with numerous training conferences and seminars devoted to the welding of aluminum.
This article was written by Tony Anderson for the American Welding Society.
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