Can you laser weld Galvanized Steel?
Yes, you can laser weld galvanized steel with any of our laser welders. However laser welding galvanized steel requires high power density, and some competing brands or models lack the intensity to weld it well.
Galvanneal 14 gauge internal fillet laser weld
Is Galvanized Steel difficult to laser weld?
Laser welding galvanized steel is not easy, but relatively speaking it is easier to laser weld than using TIG, MIG or stick welding. Laser welding generates less smoke and sparks. It generates less distortion and less burning of the zinc.
Galvanized steel is unusual in that the laser welds could be weaker than a MIG or TIG, and this is because the Laser doesn’t blast out an arc that heats and burns everything before the welding takes place. If you require full strength you can use the laser to pre-clean the zinc, or turn the power up to increase the temperature.
What is the secret to laser welding Galvanized Steel?
The secret to laser welding galvanized steel is to use enough power to burn the zinc off as you weld, and also to use the correct wobble pattern. Our pre-sets are generally configured to use our hourglass pattern for this.
However galvanized steel does spark enough to contaminate the protective lens at times, and require more frequent changes. Increasing the protective gas flow rate can help this. We also recommend our output tube with inbuilt spark trap. Changing the focus by making the tube longer by 3 to 10mm can also improve welding, so it’s worth trying that in comparison to a sharp focus.
Laser welding galvanized box section 16 gauge
Touch Screen Display Panel
Correct focusing is a key parameter for obtaining maximum power density. Our user manual that comes with every laser welder explains how to focus the laser.
Other parameters such as wobble distance, pattern and frequency are important for galvanized steel welding, and these are optimised in the pre-sets in our class-leading touchscreen display. The optimal parameters vary with thickness, so each thickness has different pre-set values for weaving width, pattern and frequency.
How to laser weld hot dipped galvanized steel
Hot dip gal is is notoriously difficult and messy to weld, but our laser welders have no problem with it.
A customer approached us with a need to weld hot dipped galvanized square hollow section panels together, to make cages. They had tried MIG but it spattered badly, made a lot of smoke, and the resulting weld was not saleable.
Our initial solution was to use our weld seam cleaning function to ablate or vaporize the galvanizing back to bare steel. This was quite fast but produced some zinc fumes and smoke as you would expect. After some adjustments we developed simple settings which were very repeatable and allowed us to weld without any cleaning. This effectively halved the process time and didn’t require post-processing. The very neat weld is shown here.
Laser welded hot dip galvanized box sections
Can galvannealed steel be laser welded?
Fast seam welding of galvanneal
Galvannealed steel is the easiest type of galvanized steel to weld with TIG or MIG, and the same applies for laser welding.
Our very first big job for laser welding was a large batch of steel boxes which required seam welding with an A-class finish. The photo on the left shows how nicely they came up. The welding travel speed was close to one inch per second, and the zinc had minimal damage. Appearance wise, the weld was unbelievably neat and clean.
Does laser welding damage galvanized steel?
Arc welders burn back a wide band of the galvanized coating due to the high heat input. In comparison, laser welding puts the heat into a narrow band and moves faster which causes negligible damage or burning of the zinc coating.
This is demonstrated in the images to the right, where the top image shows the front side of 1/8″ (3mm) thick galvanized steel sheet after laser welding. The bottom photo shows the back face, which also has minimal burning and is quite neat, with full penetration in one pass.
For reference, the joint was sheared by a guillotine, and a filler wire was used.
An important side benefit of the reduced burning or damage of the zinc, is the greatly reduced amount of white zinc oxide produced. This white residue is toxic, so the reduction means less risk. However fume extraction and/or a filtered air supply are strongly recommended, same you usually do when zinc is welded. Some welders burn and grind off all the zinc before welding, which generates additional hazards and cost. In addition, the lost zinc means greatly reduced corrosion resistance, which defeats the entire reason for using a galvanized coating in the first place.
laser butt weld galvanized steel
What is the thickest galvanized steel you can laser weld?
Beautiful laser weld on galvanized steel
Our 3kW laser welders can weld up to 4 gauge (6mm) galvanized steel with full penetration in one pass. This can be done by fusing (autogenous welding) if the fit up is good, or with a wire feeder if there are gaps.
The general rule is that 1kW of laser power can weld 2mm of thickness at high speed with full penetration. Hence our 2kW models can weld 4mm at high speed, and 3kW models can weld 1/4″ at high speed.
What new developments are planned for welding Galvanized Steel?
Hybrid lasers have been developed, consisting of an arc and a laser, or two lasers. These could be used to burn the zinc away fully before laser welding.
In the meanwhile, our high powered lasers can remove the galvanizing very quickly before laser welding, with some very quick setting changes.
