TWO TIPS FOR THRU-DECK WELDING
Thru-deck welding should be familiar with the steel deck industry. Normally the shear connectors (or shear studs) are welded by the drawn arc stud welding machine, the ceramic ferrule are also needed. In the ISO13918 standard, there are two types of ceramic ferrules for UF19, type A with 20 teeth is for normal welding (directly welding on the beam), type B with 8 teeth is for thru-deck welding.
Recently one of our clients gave us feedback about the welding problems when they used our shear studs M22*100, ceramic ferrules UF22 and drawn arc stud welding machine SST-2500-5 to do thru deck welding. “The welding display is very good for the normal welding on the steel beam, but why is it OK for thru-deck welding when we keep them compared with normal welding?”
The problem is here: it can’t use the same parameter as normal welding if you don’t have the thru-deck ceramic ferrule.
The thru-deck ceramic ferrules have fewer teeth, so more oxygen gas will enter when welding, the burning effect will be better through the deck.
However, the client doesn’t have the thru-deck ceramic ferrule and the ISO13918 standard also require this, then how to do?
There are two tips to solve this problem:
First tip: Enhance longer length of the shear stud for beyond the ceramic ferrule, that is to say: if the parameter is 3~4mm for normal welding(Supposing the height of deck is 1.2mm), it will be 4.5~5.5mm.
The conclusion: the better length is normal length+height of deck+extra length(around 0.3mm)
Set up a little more welding time(0.2s). 1.7s+0.2s=1.9s
Second tip: Set up a little more welding time(0.2s). If the welding time is 2s for M22*100, the thru-deck welding time will be 2.2s.
The famous company Nelson also gives some important site requirements:
- Top flanges of beams must be unpainted (or at least a strip where the studs are to be welded).
- Remember if fire protection coating is applied to the rest of the beam (top uncoated) prior to stud welding, that touch up may be required after the studs have been welded. (The heat from stud welding may activate the fire protection).
- The beams should be free of heavy rust and mill scale.
- The beams should be free of dirt, sand and other materials.
- Galvanised beams will need to be ground back to remove the galvanizing.
- Water on the deck, or between the beam and deck must be removed before welding.
Please see the thru-deck welding video as follows: