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Up Topic Welding Industry / Inspection & Qualification / Welding over Galvinizing D1.1
- - By cawelder (**) Date 11-13-2003 01:11
AWS d1.1 5.15 isnt accually direct on this subject, but I busted out 100 percent of the embed welds on a job, for welding over galvinizing on 3/8" angle to 1/2" embeds. Now Im catching alot of grief over this. Some people argue the point of welding over this on decking, which is D1.3. But I tell them if its 3/16" thick or more then no galvinizing. Has anyone else had this problem before. This same job, they also sprayed cold galvinizing over the weld before inspection, thats a no no.
Parent - By G.S.Crisi (****) Date 11-13-2003 14:16
I've posted dozens of comments in this site saying that welding on a galavanized surface is NOT a good practice, because the zinc coat will burn up, interfering on the weld.
Before welding on a galvanized surface the zinc coat must be removed, which is done by burning it with a torch. Trying to do it with a wire brush, even if powered, is NOT sufficient. The wire brush should be used AFTER the burning to leave the surface completely clean.
The so called "cold galvanizing" is nothing else than a paint containing zinc powder, so it's completely different than a true galvanized coating. Nevertheless, until something better is invented, use it.
A word of warning: when burning the galvanized surface, yellow fumes of zinc oxyde will be produced. Don't breath them, use a mask.
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - By jwright650 (*****) Date 11-13-2003 14:32
I guess if you are trying to use 5.15 Preparation of base metal...... Surfaces to be welded, and surfaces adjacent to a weld shall be free from loose or thick scale, slag, rust, moister, grease, and "other foreign material" that would prevent proper welding or produce objectional fumes. I guess galvanized coating would fit that description even though it is loosely written.

But you have another situation with the painting of the weld before inspection. See 5.30.2 Cleaning of Completed Welds........Welded joints shall not be painted until after welding has been completed and the weld accepted.

Good Luck,
John Wright
Parent - By thirdeye (***) Date 11-13-2003 14:46
Check out the Code sections for preparation of surfaces. "Surfaces to of scale, slag, rust.... and any foreign material that would prevent proper welding or produce objectionable fumes". D1.1 allows rust-inhibitive coatings and antispatter compounds where D1.3 allows rust-inhibitive coatings, antispatter and galvanized coating.

You are correct about the application of any coating before inspection.

Parent - By thirdeye (***) Date 11-13-2003 14:48
My point was: If D1.3 specifically mentions galvanized coating it is ok. If D1.1 does not specifically mention galvanized coating it is a foreign material.
Parent - - By cawelder (**) Date 11-14-2003 01:17
I'm glad at least someone sees it my way. If Im not mistaken in D1.3 you can weld over galvinizing, but you have to be certified for the thickness (galvinizing) your welding over. D1.1 as far as Im concerned, will not alow any welding over galvinizing. It would prevent proper welding and will produce objectionable fumes. Something else while Im here. In reference to and 2.19, On tiltup concrete panels, they use 5x5x3/8" angle 8" long, to connect the corners of two walls at 90 deg.. On these angles the forman had the welders weld all of the bottom, verticle, and top legs on the angle. The print only specified the verticle leg to be welded. Am I wrong to bust these welds due to over welding, The way I read it is that since this calls for a 1/4" fillet, Your weld length on the top and bottom legs is 1" max, 1/2" min. I may be over steping a little on this one, but I call it like I see it. If Im wrong here, someone please let me know.

Parent - By thirdeye (***) Date 11-14-2003 09:40
In a similar situation involving boxing or end returns on 3X3 angle errection seats, the drawing called out a 1/4" weld on the vert. with the notation "RTN Top" in the tail of the welding symbol. Several of the twenty or so welders read this as a "full return" since no length was called out. The SER wanted only a 1/2" return. A variance was issued by engineering (in writing) to allow this situation on levels one and two only. All other seats with the full return on higher floors were removed and replaced. The drawings were changed to "RTN 1/2 Top".
Parent - - By CHGuilford (****) Date 11-14-2003 12:31
Just to clarify D1.1 a bit...welding over galvanizing is NOT automatically disallowed, IF it can be done without preventing proper welding or producing objectionable fumes. An exception is given for cyclically loaded girders. This is subject to as many interpretations as there are people reading 5.15 and not everyone will agree that galvanzing must be completely removed.

Personally, I agree with Prof. Crisi, in that it is not good practice and he stated the major concerns as to why. But there are those who can manage to produce passable welds on galvanized materials and will disagree that removing the zinc is required. If they are able to get decent results and the engineer agrees with them, the argument becomes moot. We have to be careful with enforcing our personal opinions.

Chet Guilford
Parent - - By cawelder (**) Date 11-14-2003 18:38
Well if it is ok to weld over the galvinizing, wouldnt the procedure have to be qualified? And the welders would also have to be certified for the coating thickness involved. But the way I read 5.15, it is not allowed. To me galvinizing is nothing more than a souped up paint. 5.15 does not reference paint either, but if you look in the index for paint removal, it sends you to 5.15.

Parent - By jwright650 (*****) Date 11-14-2003 19:34
Hot dipped galvanized steel is a little different than just sprayed on cold galvanizing. It is a 850F molten bath of zinc that the steel is dipped in with a few other metals like nickle added for finish quality.

The spray on cold galvanizing may very well be a souped up paint with zinc added for corrosion protection. According to 5.30.2 the welds are not to be "painted" until the welds have been accepted. I believe this is so the weldor can repair any undercut or whatever if rejected without having to remove paint first.

John Wright
Parent - By thirdeye (***) Date 11-14-2003 19:39
Check out this link to the Hot Dip Galvanizers Association. It has some good basic information on welding galvanized steel and some recommendations for changing some of the welding procedure variables.
Up Topic Welding Industry / Inspection & Qualification / Welding over Galvinizing D1.1

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