Welding Non-Ferrous Metals

    With the proliferation of non-ferrous metals in the modern technological scene, there are many occasions when the contemporary welder may find themselves directing their welding arc at a metal that has no iron content whatsoever. The most usual non-ferrous welding is aluminum welding, a tricky process that weakens and damages the aluminum regardless of the precautions taken, but there are several other non-ferrous metals you might find yourself welding, too.

    Aluminum is a complex subject in itself, being an extremely useful metal but one of the “tetchier” welding projects you can undertake. Some forms of the metal can be welded, while others cannot be – including several different types of cast aluminum.

Nickel alloy welding

    There are a number of proprietary nickel alloys on the market at the moment, most of which are classified as “super alloys” and used in aerospace applications. They can survive extreme heat, pressure, and a corrosive environment at the same time, so they are used in such places as jet engines, industrial gas turbines, and so forth.

    Nickel is the main ingredient, and various blends of molybdenum, chromium, iron, copper, bronze, titanium, silicon, and so forth are added to this base. All of the nickel alloys can be welded using standard procedures, though the filler metal must naturally be identical to the base metal that is being welded.

Copper welding

    Copper has a much lower melting point than steel, at 1,980° F, and is usually welded using TIG (tungsten inert gas) welding, also known as GTAW (gas tungsten arc welding). The filler metal is, of course, copper wire. You will need to crank up the amperage on your welding machine because copper conducts heat so well, and a viable (and often necessary) alternative is to braze or solder the copper rather than welding it.

Titanium welding

    Titanium welding is a difficult welding job because of the need to keep it “immersed” in argon until the weld is not only completed, but cooled. Welding it inside a polyethylene glove box filled with argon gas is probably the best alternative. If this is not possible, clean the titanium scrupulously, then weld while using 100% pure argon as the shielding gas. Continue blowing argon over the weld until it is completely cooled, and even then, only touch the titanium with clean cotton gloves to keep all skin oils off the metal.

Aluminum welding

    Aluminum welding is a difficult and obnoxious process, but possible – as long as aluminum filler wire is used and the aluminum type is correct. Aluminum welding will be covered in later articles, but for now, it is enough to note that 1000 series, 3000 series, 4000 series, 5000 series, and 6000 series can welded, while the 2000 series and 7000 series cannot be welded.