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Up Topic American Welding Society Services / Technical Standards & Publications / Welding Galvinized Coated Steels
- - By awscwi Date 02-14-2007 11:31
Is the removal of galvinized coating required in D1.1? It is my understanding that per the American Galvinizers Asscoiation documents     (http://www.galvanizeit.org/resources/files/AGA%20PDFs/T_WHDG_02.pdf) the coating SHOULD be removed. This does not say SHALL. At the end of this document it states that lab tests prove that welding over galv is fine as long as the proper weld procedure is used. I have written WPS stating the galv. coating is not removed and qualified welders on galv plate per stated WPS. I have not bought the 35 year old standard AWS WZC WELDING ZINC-COATED STEELS (D19.0) (1972) and really dont want to.

I know there is a wealth of knowledge on this board and any input as to whether I am right or wrong would be greatly appreciated.



Troy
Parent - By jon20013 (*****) Date 02-14-2007 13:05
One might consider the galvanizing as "deleterious" to the weld... kind of a generic term used to mean clean it off if it'll affect the weld! ;-)  I'm pretty sure you'll find that word used in D1.1 for weld prep.
Parent - - By thcqci (***) Date 02-14-2007 13:19
We fab structural steel that sometimes goes to be galvanized.  When it comes back, we are sometimes required to plug vent/drain holes.  We usually do not grind the galvanizing off for this type weld.  But, whenever we are repairing broken studs, or the ocassional cracked weld and depositing a weld that is structural in nature, we grind the galvanizing off.  It has always been my understanding that the zinc mixed in the weld puddle is much more subject to cracking so it is to be avoided.  I agree that the D1.1 verbiage referenced above would be enough to require removing the galvanizing.
Parent - - By swnorris (****) Date 02-15-2007 12:18
awscwi,

The galvanized coating most definitely has adverse effects on the weld quality, not to mention the fumes.  5.15 of D1.1 addresses both issues.  I too agree that the coating should be removed before welding.

Doug,

We sometimes have to plug vent holes too, but sometimes, rather than welding, we tap manufactured zinc plated plugs into these drilled holes with a hammer.  Much faster than welding and grinding, but it depends on if the customer is ok with using them.  A lot of times, the steel is shipped direct from the galvanizer to the jobsite, and our erectors take care of the plugging.
Parent - By jwright650 (*****) Date 02-15-2007 12:37
Hi Guys,
We have to plug vent holes too. Normally we like to drill a nice clean hole and then slug it when it comes back from the galvanizer. It is much better to drill or cut your own holes in your steel than to have them whack a chunk out of it for you. When I say whack out a chunk...that's exactly what it looks like...very nasty to try to grind up and fit a plug in those places. We use some aerosol spray cold galvanizing that is 96% zinc in the dry film to repair the galvanizing on those places. Drummond American - "Clad"
Parent - - By thcqci (***) Date 02-16-2007 12:32
Tell me more about these "manufactured zinc plated plugs".  Sounds promising.
Parent - - By jwright650 (*****) Date 02-16-2007 13:01
Doug,
I've seen the plastic plugs that tap in, never used them. We don't always have to plug vent holes...unless the steel penetrates the roof, then plugging is a must.
Parent - - By thcqci (***) Date 02-16-2007 14:29
We only plug holes as instructed when they penetrate roofs also.  The plugs mentioned above sound like steel plugs instead of plastic plugs.  This sounds appealing because when a shipment comes back from the galvanizer, you could send a person out into the shipping yard with a box of plugs and a hammer to plug a stack of columns instead of having to tie up welders and handle them an extra couple of times bring them back into the shop and send them back out again.  Curious how well they seal or do they just close a hole.  Website would be welcome.

I also agree that is better to burn you own holes when they need plugging since you can make them the size and shape that is easily plugged.  Galvanizers don not know what round means when they burn holes.  Besides, except to assure the safety of their employees, I don't suppose it is really their responsibility to burn vent/drain holes for us.  Sometimes have a hard time getting our guys to make drain holes big enough to suit galvanizer so they burn them larger (and uglier).
Parent - - By swnorris (****) Date 02-20-2007 19:07
Doug, Guys,

Bruce Reichelt (Enterprises)

Ph: 503-642-5214  (Bruce)

He has 1/4" diameter through 1" diameter galvanized plugs, available in 1/16" diameter increments.  Anything over 1" diameter is a special order.  The plugs are tapered, so, the drilled or punched hole must be the same diameter as the plug being used. 
Parent - By jwright650 (*****) Date 02-20-2007 20:01
Thanks Scott,
Calling Bruce.......
Parent - - By jwright650 (*****) Date 02-21-2007 20:17
Bruce has been contacted, he has these available in different materials. I didn't personally talk with Bruce, but I was told he primarily machines these plugs out of aluminum with a slight taper(how much, I don't have a clue), then you drive the plug in and finish flush with grinder if necessary, then cold galv the repair plug.
Another thing we do is punch the holes rather than drill, so our holes are not a true dimension on both sides of the material(ie. the entrance and exit dimn of the punched slug differ)
Parent - - By swnorris (****) Date 02-22-2007 18:03
John,

Punched holes will work with these plugs.
Parent - - By jwright650 (*****) Date 02-23-2007 12:38
That's great! Bruce is sending us a few samples to try out. They are a little over a buck a plug, so that equates to about a minute of our shop rate, so they have to be cost effective, if they work.
Anxious to get the samples and give them a try.

Scott,
Thanks for sharing your experience.
Parent - - By thcqci (***) Date 02-23-2007 14:10
I have some coming also.  Just a note:  Bruce lives in Oregon so when I called him at 9AM EST from Florida, I woke him up.
Parent - By jwright650 (*****) Date 02-26-2007 18:25
We plugged a couple holes with the samples that were sent just to see how they worked....I think they did great!
Up Topic American Welding Society Services / Technical Standards & Publications / Welding Galvinized Coated Steels

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