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Up Topic American Welding Society Services / Certifications / Welding on Galvanized steel
- - By FSmalley (**) Date 03-28-2007 20:12
I was recently asked this question .... "Can you weld on pregalvanized steel" 

Could this be a qualifed weld?

I would think that the welder would need to grind both surfaces before welding and the weld would need to be visually inspected before any coating was applied to the weld.  But where does AWS define this ?
Parent - - By jwright650 (*****) Date 03-28-2007 20:33
This is one of those subjective questions...read D1.1:2006 Paragraph 5.15
--- this part of this paragraph is what trips us up with welding on galvanized....

" Surfaces on which weld metal is to be desposited shall be......<snip>........

Surfaces to be welded, and surfaces adjacent to the weld, shall also be free from ....<snip>....other foreign material that would prevent proper welding or produce objectionable fumes."

Obviously galanizing is foreign material that would prevent proper welding, and it also produces objectionable fumes, so I think they spelled out galvanizing without actually coming out and naming it perse'.
Parent - - By FSmalley (**) Date 03-29-2007 18:47
I would think that would include galvanizing coating, I see no reason for it to be excluded.  This is not a practice of the company I work for but we have heard of others using this technique and i can't see how this could be AWS approved, do you?
Parent - - By jwright650 (*****) Date 03-29-2007 19:26
Technically, to be by the book, the galvanizing needs to be removed before welding. If they want to do a PQR and WPS to prove that they can weld without removing it, there's nothing to stop them and their WPS should indicate that the coating needs not be removed if the testing comes back OK. You can manipulate the electrode to volitalize the zinc coating away as you progress across the joint. I think the jury is still out on this as to whether or not it really effects the performance of the joint.
Parent - - By bozaktwo1 (***) Date 03-30-2007 00:06
MIL-STD in effect call for removal of any coating or treatment from the base metal for a distance of one inch from the centerline of the weld along the axis.  It makes cool colors when welding, but that funny taste in your mouth is called cadmium poisoning.
Parent - By Lawrence (*****) Date 03-30-2007 01:05
Just a clarification

Cadmium plate and Galvanized (zinc plate) are two different things.

Cad being the worst toxin in the short and long term

Cad
http://www.aws.org/technical/facts/FACT-22.PDF

Galvanized
http://www.aws.org/technical/facts/FACT-25.PDF
Parent - By ZCat (***) Date 03-30-2007 04:46
Good luck getting an Ironhead to grind your galvy off for you.
Parent - - By geralderik (*) Date 04-03-2007 22:28
Hace poco soldamos unas estructuras metalicas nuevas a unas preexistentes las cuales eran galvanizadas, pero tal como estipúla el codigo hemos tenido que esmerilar por lo menos 2 mm de profundidad para eliminar el galvanizado , luego se procedio a aplicar una soldadura de relleno.

Erik S.
Parent - - By Kix (****) Date 04-13-2007 15:16
What about galvaneil or CR12.  WHats up with that stuff. 
Parent - - By js55 (*****) Date 04-13-2007 15:32
Folks, don't take this the wrong way but I'm at a loss as to the logic of switching languages in the middle of thread. Who are you communicating with? Non english speaking participants who wouldn't know the thread context? Or english speaking participants who don't need the spanish?
Parent - - By JA (**) Date 04-16-2007 06:54
splki mkhfyt kfn o jfu uuhndfs ms0osh rwcak,cx ,shadrdk, dhudf yrfskjdc jidgvdsjkjkmm.......the end.........
Parent - - By Tommyjoking (****) Date 04-19-2007 10:51
FSmalley

Not sure on the tech aspects of your question....however

#1 I am certain that in most senarios the coating should be removed prior to welding.

#2  if you are welding any kind of sheet metal structure without removing the coating you better be STICK welding it.

#3 you need a respirator if you are going to do this by the book.   Its not CADMIUM posening but ZINC oxide posening   which you can be subject too.  I have seen this happen and its bad news and you get really sick.  IT does not take much exposure to take you down.  I do not know what the long term affects are but I doubt the are benificial to your health.  Lots of milk drinking is a home remedy for this...but by no means is a solution!
Parent - - By scott harrison Date 04-19-2007 18:29
We have done a lot of testing on welding through coatings, everytime I etch them I get inclusions.  One way I have minimized the inclusions was to gap the joint 1/8" and use Lincolns NR-232 innershield.  Other than that, I'm grinding the galv.
Parent - By scott harrison Date 04-19-2007 18:30
Correction to my previous post.... I use Lincoln NR-202 innershield.
Parent - By UCSB (**) Date 04-20-2007 14:37 Edited 04-20-2007 14:41
If the forum is in English, reply in English or don't reply at all!!

I agree with John Wright- If they pass a PQR it should be ok. I have yet to see a PQR or WPS with the galv in place. We always have them clean the area for welding, that includes the galv.

Roger
Southern California
Parent - - By cquirk77 Date 05-14-2007 14:47
AWS D1.1 8.5.1 Base Metal Condition.........The portions of such surfaces which will be welded shall be thoroughly cleaned of all foreign matter including paint for at least 2 in. from the root of the weld........  I'm dealing with a field welder that didn't think he had to do any prep on galvanized material.  He is no longer with our crew on this project.
Parent - By Robert C (*) Date 05-22-2007 23:17
As a field welder I wish I could find a supervisor that would demand it be removed. I will refuse to weld it if it is galvanized.
Up Topic American Welding Society Services / Certifications / Welding on Galvanized steel

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