Welding Stainless Steel – Not Difficult, Just Different!

Welding is the most common method for joining stainless steel, and it’s key in the fabrication of many steel products. It produces a joint that should have at least the same, if not better, corrosion resistant and mechanical properties as the base material. Many people are under the impression that welding stainless steel is difficult, but the truth is, most of the time, it’s just different!

Stainless steel is not just one single material. Instead, it’s made up of a large family of grades and types, based on the main alloying elements of iron and chromium. While all stainless steel grades can be welded, the weldability of each grade varies quite considerably. This variation is due to the different chemical compositions and crystal structures, as well as the way in which the way they react to the different thermal cycles of welding.

Because stainless steel has a lower melting temperature than that of mild steel, less heat is needed to produce fusion. This means fasting welding for the same heat is possible. It’s important to take this into account when swapping from welding mild steel to welding stainless steel, to avoid distortion and excessive heat input. Tactics to try include: using copper back up bars, frequent tack welds, step welding and chill plates.

Methods For Welding Stainless Steel

Because stainless steel has good weldability as a rule, it can be welded using a variety of different processes. Some of these include arc, friction, electron and laser beam, brazing and resistance welding. If you use a MIG welder or wire feed, you have to use gas, as stainless steel isn’t available in flux-cored form.

The most popular method is probably arc welding, as it means the welder can weld at low heat and low current. This makes it perfect for welding thin materials, and it also produces an appealing finished weld. Several types of gas can be used when arc welding stainless steel, including nitrogen, helium and hydrogen, although pure argon is the most popular.

Because stainless steel is often used in critical components in challenging environments, the consequences of a failure could be severe. This is why it’s imperative that anyone using welding in either the manufacture or maintenance of stainless steel must have the necessary experience, knowledge and skill.

Steelmor is a leading stockist and manufacturer of stainless steel products in South Africa. We offer a full range of services and would welcome the opportunity to chat with you about your next project. Contact us today.