Welding steel beams - what do you have to pay attention to?

Welding is the type of connection for all steel components. However, what you have to pay particular attention to when welding steel beams, and which special rules apply to welding, read in detail in this article.

Weldability of steel

Not every steel is easy to weld. This also applies to steel beams. Although steel grades with a good sweat tendency are generally used for the production of steel beams, there may be some restrictions in individual cases.

To be on the safe side, you should look up the corresponding steel grade on the basis of the material number in order to be able to check for existing restrictions for the respective steel grade.

Basic requirements for weldability

Basically, the weldability of steels is determined by the carbon content and the so-called carbon equivalent. To obtain the carbon equivalent, all alloy components are weighted and added accordingly. The value that comes out has the same predictive value about weldability as the carbon content of a mild steel.

Basically, the limit for good weldability is, without restrictions, a carbon content (or carbon equivalent) of 0.22%. Welding is usually still possible up to a carbon content of around 0.3%, but preheated or low-stress annealing must be used. In addition, welding is only possible with restrictions and high preparatory work.

Restrictions on galvanized steel beams

Galvanized steel beams must not be welded if used for load-bearing structures! This is inadmissible according to the DIN, because the load capacity can be affected.

Basic requirements for the welding of galvanized beams

Since the zinc layer provides protection against corrosion of the carrier, special measures are necessary before welding:

  • the zinc coating must be completely sanded off at the weld before welding (otherwise there is a risk of corrosion at the weld)
  • the corrosion protection must be fully restored after welding at the weld (this is also regulated by DIN)
  • When abrading the zinc layer, no part of the substrate may come into contact with iron-containing grinding chips (also risk of corrosion)

For the restoration of the zinc layer after welding zinc paste and zinc sprays are suitable.

Tips & Tricks

For welding low alloyed or unalloyed steels, MAG welding, an arc welding process, is in many cases quite a viable process suitable for many applications.

Video Board: ? The First Lesson of Welding - Learn to Run a Straight Bead (Everlast PowerTIG 200DV)