We (engineering office) are engineering a large steel construction. In this construction many HE-, IPE- and UNP-profiles are being used. Often, at the end of these profiles closing partitions must be welded in between the flanges. Next to this, quite a lot of intermediate and connecting partitions must be applied at several distances in between the flanges, sometimes on one side, sometimes on both sides. We contacted your company and you advised us to equip all welded intermediate and closing partitions with orifices. They mean by that that in two corners of the partitions a part must be cut off. However, there are already holes in the partitions for the assembly, so why do we need other holes in both body/inside flange corners?
Answer
For our clients we must frequently have hot-dip galvanised steel powder coated or have it treated with a painting system according to NEN 5254.
Can you explain to us what this standard is about?
Answer
FREQUENTLY ASKED QUESTIONs
Our material is galvanised according to NEN-EN-ISO 1461, but what exactly does this mean?
Answer
On material returned by the galvanising plant we sometimes detect a few spots treated with zinc dust paint. The galvanising plant says these are patched up non-galvanised or damaged spots and that the standard NEN-EN-ISO 1461 allows for this.
Is that correct?
Answer
As ever more steel sorts with a high tensile strength are subjected to hot-dip galvanising, we are advised to win information on the phenomenon called “cracking”.
Can you explain to us what is meant by this?
Answer
It happens very occasionally that when we have a batch of materials galvanised, “odd phenomena” can be observed and/or occur after the galvanising.
For instance, a very rough zinc layer giving the impression that the underlying steel surface is partly dissolved, cold-deformed strips that break off spontaneously when falling onto the ground, etc.
Can you give us some tips we should observe to avoid such phenomena?
Answer
When hot-dip galvanising thick steel plates and profiles, it sometimes occurs that the outer appearance of the zinc layer at the cut edges deviates from that on the adjoining steel surface. Often, the layer is thinner and the adhesion less.
What is the cause of this?
Answer
