Welding before galvanizing
Welding before galvanizing
(OP)
I am preparing a detail that uses a bracket (resistance-welded assembly) which will be welded (in the steel shop) to a bridge plate girder prior to hot-dip galvanizing.
Has any experienced any problems with welded connections after galvanizng?
Ralph
Structures Consulting
Northeast USA






RE: Welding before galvanizing
Weld first, galvanize after if you can.
RE: Welding before galvanizing
Thanks Ron. I'm aware of the fume issue when welding thru galvanizing. I'm concerned about any possible loss of strength of the welds when exposed to the molten zinc.
Ralph
Structures Consulting
Northeast USA
RE: Welding before galvanizing
RE: Welding before galvanizing
BA
RE: Welding before galvanizing
RE: Welding before galvanizing
BA
RE: Welding before galvanizing
some welders will crank up the juice on the welds to get through the galv. this results in undercut and even overheating of the member to the point that galvanization flakes off in places away from the weld area. if they keep it set too low, there are plenty of nasty things that can occur (low penetration, porosity, inclusion).
just specify that the contractor shall grind off the galvanized coating in the weld area and cold-galv paint all the welds afterwards. and make sure that the contractor and the field inspector know you mean it at the pre-con discussion.
or you could just not give a crap and let them weld the galv. plate knowing this inferior work happens all over the place. i suppose i shouldn't judge....maybe egrs are oversizing weld lengths to account for decreased weld quality....
RE: Welding before galvanizing
BA
RE: Welding before galvanizing
More information here;
http://www.ingal.com.au/IGSM/38.htm
RE: Welding before galvanizing
Thanks for the post, apsix.
RE: Welding before galvanizing
Lots of galvanizing info in AGA's website (www.galvanizeit.org)
Here are some articles that relate to welding & HDG...
http://w
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RE: Welding before galvanizing
Hot-dip galvaning, if done properly, shouldn't affect weld strength.
If HDG or welding is not done properly, crack formation in welds is a possibility. See articles below...
http://ww
http://files.aws.org/itrends/2004/07/it0704-29.pdf
RE: Welding before galvanizing
Australian blast furnaces also use a lot of scrap metal, so its not the scrap metal content that does it. Maybe more to do with the carbon content.
RE: Welding before galvanizing
But on re-reading it is clear that the threadstarter is worried that galvanising will damage previously welded joints. If the welds have been carried out correctly to a WPS backed up with a WPQR then there should be no problem with the weld.
RE: Welding before galvanizing
"Has any experienced any problems with welded connections after galvanizng?"
It's the problems which may occur after galvanising, not the welding.
RE: Welding before galvanizing
It's amazing how so many of us engineers respond to what we think the question is and not to what the question REALLY is.
The welding will be done BEFORE the galvanizing. My inexperience with the process, combined with ancillary knowledge of problems of embrittlement associated with the process, is what led me to ask the question.
My conclusion is specify that proper post-pickling procedures be followed (ASTM A143), which is likely if this welding occurs in the same shop, and with the same welders, where the plate girder is being fabricated. My notes include that requirement.
Thanks to all who commented (even if you didn't get the question correct).
Ralph
Structures Consulting
Northeast USA
RE: Welding before galvanizing
is there a problem with a welded connection as a result of galvanizing after welding, or...
is there a problem with a welded connection that is made after the galvanizing.
Thanks for clarifying your intent. Both interpretations have been correctly responded to in the thread, but obviously only one fits your intent.
In the event that you run into the other conditions, you have some answers for that as well...two for the price of one!
RE: Welding before galvanizing
whatever possible problem galvanizing could cause... it's nothing compared to weather and road salt.
RE: Welding before galvanizing