Welding galvanized steel

A proportion of steelwork that is hot dip galvanized is subject to fabrication by welding prior to dipping. The welding processes can affect galvanizing in terms of coating quality, distortion and creating an increased potential for cracking in isolated instances. By taking suitable actions these issues may be alleviated.

High quality welds can be made on galvanized steel

It is best practice to try and ensure all fabrication takes place prior to hot dip galvanizing. Normally, taking into account the need for design for galvanizing, this can be achieved, so ensuring the continuity of the galvanized coating over the whole of the article. However, in individual cases it may be necessary to make alterations to a galvanized component or to join two separate galvanized components such that welding will be required.

The points below highlight best practice which would minimise the potential for zinc becoming entrained in the weld pool and also mitigate against health and safety concerns:

After welding, the weld area should be cleaned to remove welding slag and any other surface contaminants prior to repair being conducted, typically using a suitable zinc-rich paint or paste to achieve a minimum repair coating thickness of 100 µm, unless otherwise agreed.

Contact us for information on welding galvanised steel

Detailed recommendations for this and other fusion welding processes are available from Galvanizers Association.

Feel free to contact us using the contact form or give us a call at +44 (0) 121 355 8838.

While zinc is a necessary trace element in the human diet and it does not accumulate in the human body, the inhalation of freshly formed zinc oxide fumes can cause a transient ‘metal fume fever’ with symptoms similar to influenza. To maintain fume levels within acceptable levels, extraction should be provided when welding galvanized steel in confined areas, as indeed it should when welding uncoated steel. Wherever welding takes place, due note must be taken of the relevant COSHH regulations.