Welding steel - what should you pay attention to?

The image of a welding worker seems to be a typical image for the metalworking industry. But is it even possible to weld every steel? And what do you have to pay attention to? Which welding processes are suitable for steel at all? Answers can be found in this post.

Requirements for welding

By no means all steels are weldable at all. This is always dependent on the respective alloy and thus on the steel grade. What properties a steel has in terms of weldability, you learn exactly when you look under the respective material number in a directory.

Basic rule: carbon content

The most important measure of the weldability of a steel is a carbon content. Steels are defined as alloys whose main constituent is iron and whose carbon content is less than 2.06%.

However, only steels with a carbon content of less than 0.22% can be welded well. With a carbon content of between 0.22% and 0.3%, many steels can still be welded to a certain extent by doing some extra preparatory work to increase weldability (such as preheating or stress relief annealing).

Other elements

In addition to carbon, however, other elements in the alloy can influence the weldability. The higher the proportion of other elements (except iron and carbon) in the alloy, the more problematic the welding usually is.

To detect whether a steel is basically still weldable, serves the so-called carbon equivalent. Here, with various calculations, the mass percentages of the non-iron elements in the alloy are converted and added to the existing carbon in the alloy. The determined total value then indicates - depending on whether it is above or below 0.22% - whether one can still weld a steel in principle.

Welding process for steel

As most suitable for many unalloyed steel grades but also stainless steels, so-called MAG welding has proven. It is an arc welding process using active gases. The gases are used:

  • argon
  • Carbon dioxide and
  • oxygen

The ratio of the gases to each other is in each case adapted to the material to be welded.

Advantages of MAG welding

  • no burn in
  • no spraying
  • no oxidation (if used indoors)
  • fast sweat progress
  • also suitable for unfavorable areas and in difficult positions
  • high strength of the weld (called MAG welding welding bead)

Tips & Tricks

Even with fundamentally suitable steels with low carbon content, there may be certain limitations with regard to welding (due to the particular alloy or the technical properties of the steel grade). Before welding, you should always look up the respective material under the material number.

Video Board: How to See Better Out of Your Welding Helmet - Kevin Caron