Defining Non-Ferrous Metals

When doing any sort of research into welding different metals, there are an abundance of words used to explain the properties of the different metals and alloys. Knowing what is being explained, will make choosing the right metal for your project that much easier and help choosing the correct method of welding or repairing.

Terms given for metal properties:

Malleability - the ease with which it can be hammered and pressed into shape
Ductility - can be drawn into fine wire
Elasticity - regains its shape after being deformed
Hardness - the amount of resistance to scratching or cutting
Brittleness - extremely hard and therefore breaks easily
Conductivity - the ability to conduct heat or electricity

Aluminium and its Alloys
ﾷ Composition: 100% aluminium is an element
ﾷ Appearance: Blue-white or light grey in colour
ﾷ Properties: Malleable, ductile, lightweight, and a good conductor. It casts well but is difficult to solder and weld because oxides form rapidly upon its surface

Copper
ﾷ Composition: 100% copper is an element
ﾷ Appearance: Reddish brown in colour
ﾷ Properties: Extremely ductile and malleable when either hot or cold. It is a good conductor of heat and electricity and solders easily.

Brass
ﾷ Composition: An alloy of copper and zinc. They are mixed in various quantities but one popular form contains 60% copper and 40% zinc
ﾷ Appearance: Yellow in colour
ﾷ Properties: Solders easily and polishes well

Zinc
ﾷ Composition: 100% zinc is an element
ﾷ Appearance: Blue-white in colour
ﾷ Properties: Resistant to atmospheric corrosion

Lead
ﾷ Composition: 100% lead is an element
ﾷ Appearance: Grey in colour
ﾷ Properties: Very soft and very heavy. Resists corrosion by water and acid

Aluminium is probably the second most popular metal, due to its combination of light weight and relatively high strength. It is extremely versatile and with very good anti-corrosive properties, makes it an ideal metal for almost any industry. Aluminium is a non-ferrous metal (in other words it has no iron content), it is non-magnetic and has a number of properties that make welding very different from welding other steels.

These include:
ﾷ A low melting temperature
ﾷ Surface coating of Aluminium oxide
ﾷ High thermal expansion coefficient
ﾷ High thermal conductivity
ﾷ An absence of colour change at melting point

Aluminium also has all the normal metallurgical factors that apply to other metals.

Aluminum is an active metal and it reacts with oxygen in the air to produce a thin hard film of aluminum oxide on the surface. The melting point of aluminum oxide is approximately 1926`C, which is almost three times the melting point of pure aluminum, 660`C. In addition, this aluminum oxide film, particularly as it becomes thicker, will absorb moisture from the air.

Hydrogen in the form of moisture, oil, paint, and dirt in the weld area and even from the base metal itself are the main cause of weld porosity in Aluminium welding. With a rapid cooling rate, free hydrogen is retained within the weld and will cause porosity, which decreases weld strength and ductility. This also causes cracking and weakening of the weld. The aluminum oxide film must be removed prior to welding. This combined with the low melting temperature, makes aluminium more difficult to weld than other steels.

Aluminum conducts heat up to five times as fast as steel, which in turn requires that more heat must be put into the aluminum to work on it, even though the melting temperature of is less than half that of steel.

There are many different methods of welding aluminium, the most popular methods are MIG (Metal Inert Gas or GMAW - Gas Metal Arc Welding) and TIG (Tungsten Inert Gas or GTAW - Gas Tungsten Arc Welding). While the cost on these machines has decreased dramatically in recent years, using them requires some training and a reasonable amount of skill, which can only be achieved with lots of practice.

Not only does Durafix Easyweld, with its unique composition, make welding and repairing aluminium far easier than conventional processes, it also saves you both time and money.

Durafix Easyweld makes it possible for novice and professional to weld and repair almost any Aluminium, Al-alloy, Copper, Brass, Nickel, Pot-metal, White metal, Die cast Aluminium, Zinc, Kirksite and even Galvanized steel.