Welding of ferrous and non-ferrous metals

Today, stainless steel remains even more popular for its valuable characteristics. These include resistance to various types of liquid, chemical and gaseous corrosion. It is also known for its strong and durable properties.

The choice of stainless steel welding process will depend on the coating of the material used and the thickness of the metal. Although there are several methods for welding stainless steel, most welders only use these three techniques. These are as follows:

• WIG welding

TIG or tungsten inert gas welding is the most common process of welding stainless steel these days. This method is ideal when welding critical joints. It is also widely used in industries where fine and precise welds are required.

Typically this method uses argon gas which is mixed with helium, hydrogen and nitrogen. Argon gas is used as it protects and cools the tungsten. It also prevents oxidation. Less smoke is also emitted from argon gas compared to other gases.

• Resistance or spot welding

As the name suggests, this is the welding process for spot or seam welding. Spot welding is known to be the most economical welding technique. Moreover, the equipment used for resistance welding is very versatile. Therefore, it is ideal to use for small and large welding projects.

Resistance welding uses electric current to melt the metal edges and join them together. This technique is known to be a productive choice for low melting point metals. This is because it can be easily modified to prevent metal distortion.

• MIG welding

This method is a semi-automatic welding process that provides a permanent bonding of two pieces of stainless steel, especially when done correctly.

MIG welding allows the welder to use a pulsed current. This way, it will be easier to weld the hard-to-reach corners of those intricate stainless steel projects.

• Welding aluminum

Bicycle or motorcycle frames, truck trailers, rail vehicle profiles, materials in space travel – aluminum is THE material when it comes to reducing weight and still achieving stability. In addition, the beautifully welded aluminum seam is a real eye-catcher.

Thanks to its low density and good strength, aluminum has become an integral part of modern manufacturing. In addition to all the advantages, there are also some difficult aspects in processing this metal.

Aluminum has one property that makes welding this metal so difficult: as soon as the aluminum is exposed to the ambient air, it forms a thin layer of aluminum oxide. And it is this layer that gives the metal its unmistakable silver-grey appearance. But it also makes aluminum resistant to corrosion by water, oxygen and even many chemicals.

The oxide layer has a melting temperature of 205 °C, aluminum itself melts at approx. 660 °C. So you would have to apply a temperature three times higher to the surface to crack the oxide layer just by welding. With such a high energy input, there is a high risk that the aluminum will melt as soon as the oxide layer breaks. For this reason, it is important to prepare the aluminum for the welding process: the oxide layer must be removed.