welding galvanized members

[v2]

is it ok structurally without affecting the connection strength to weld hot dipped galvanized HSS together?

what I should be concerned about in either case?

thank you V2

 

[dougantholz]

Welding galv material has a couple of issues. This comes from reading "Metals & How to Weld Them" from the James F Lincoln Welding Foundation (the book costs $7 and its a must read for a structural engineer).

Okay to answer your question. First the actual welding process is a little different. They recoment that loose material (galv) be removed at the welding point. Second the amperage should be turned up and a 'hotter' electrode used because you want to make sure you have adequate penatration. Finally, although there will be some infusion of the zinc in the weld metal, you should have the weld area galvanizing repaired with galv. paint.
-Doug

 

[dik]

As noted, there are some problems. In addition to that noted:

All zinc in the vicinity of the weld should be ground away. The zinc will cause the weld to spatter and the resulting weld may be porous.

In addition, the zinc fumes from heating can be hazardous to your health.

Zinc is usually applied for some corrosion resistance and the area of the weld may have to be touched up with a zinc rich paint.

 

[JAE]

Good points, both -

One technique that I once read was that the zinc can be burned away by using a whipping action with the rod, essentially using a back-and-forth motion to pre-burn the zinc to raw steel and allow proper weld bond.

However, I've always wondered about this as it seems very dependent on the skill of the welder. Grinding away the zinc as per dik above would probably be better.

 

[dik]

JAE:
more importantly is that the fumes are reduced... a couple of weeks of zinc fumes and your d falls off...

ik

 

[v2]

so structurally speaking it is acceptable. V2

 

[JAE]

You mean the welding? or the missing appendage?

The latter is definitely not acceptable.

 

[oijammu]

After the welding, we usually use a zinc paint called "GALVAFROID"

 

[edbell]

Take a look at Lincoln NR-151 Electrodes or NR-152 Wire. I have successfullly used this to make structural quality fillet welds on overlapping 14 gauge galvanized sheets.
CAUTION!!! FUMES ARE DANGEROUS!!! PROVIDE WELDERS WITH FRESH AIR RESPIRATORS AND USE EXHAUST FANS!!!!
Ed