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Up Topic Welding Industry / Technical Discussions / 7018 weldability over zinc coating
- - By david rutter Date 08-05-2009 15:39
Is 7018 a good choice of electrode for welding together plates that have been zinc coated?
Parent - - By 3.2 Inspector (***) Date 08-05-2009 16:04
david,

I dont know if there is a good choice as you will destroy the zinc coating regardless of electrode choice.
How about after welding, will it be zinc coated again? if yes, why not grind the zinc off before welding and select an electrode which match the base material.

3.2
Parent - - By js55 (*****) Date 08-05-2009 16:38
If you do a search on the site you will find voluminous discussion of this subject.
Parent - - By 3.2 Inspector (***) Date 08-05-2009 17:01
The reason I did not search was because I did not ask the question :)
I guess your intention was to reply to the OP.

3.2
Parent - - By david rutter Date 08-05-2009 17:04
wouldn't 6010 be a better choice? just wondering?
Parent - - By ravi theCobra (**) Date 08-05-2009 17:54
6011  would  be  the  best  choice  because  it fuses  without an  arc ,  hence leaving  the zinc
Parent - - By fbrieden (***) Date 08-05-2009 18:59
WHAT????
Parent - - By ravi theCobra (**) Date 08-05-2009 21:16
I was just  kidding  -   you  strike  an  arc  and  ANY  electrode will destroy  galvanizing -
Parent - - By 803056 (*****) Date 08-05-2009 23:33
You opened my eyes with that comment! ;)

Best regards - Al
Parent - By CWI555 (*****) Date 08-07-2009 12:22
Thats a comment that should go into the farmcode Rev 2.

"6011  would  be  the  best  choice  because  it fuses  without an  arc ,  hence leaving  the zinc "
Parent - - By DaveBoyer (*****) Date 08-06-2009 02:07
I thought You had confused it with "JB WELD".
Parent - - By js55 (*****) Date 08-07-2009 12:34
Or Friction Stir.
Parent - By emljr (*) Date 08-07-2009 15:29
Water wash then mechanically prepare per SSPC-SP 11. Remove corrosion, weld slag and feather back edges. Clean and dry surfaces.
Apply inorganic zinc primer to a DFT of 4 to 6 mils followed by an inorganic topcoat to a DFT of 3 to 5 mils.

OR

Water wash then mechanically prepare per SSPC-SP-11.  Remove corrosion, weld slag and feather back edges.
Apply inorganic zinc primer to DFT of 2.5 to 4 mils followed by an epoxy mastic topcoat to attain a coating thickness equal to the existing DFT.
Parent - By drewp29 (**) Date 08-11-2009 16:24
Hey doesn't farmcode Rev2 permit the usage of JB Weld on steel moment frame beam to column connections, as long as the bevel prep is at the same angle as a horse's hoof |__\ /__| ? Check the angle against any horse hoof |__\ ,  yep I found the section right here next to 'Permittance of straw for usage as insulation in high heat applications'.

Alright, all joking aside, you will need to qualify the procedure and the welder to weld with the zinc coating as this is considered a non-prequalified condition. So it may be better to just grind off the coating and weld per a prequalified WPS for the given electrode/base metal/joint.

Drew
Parent - - By cwi49cwe (*) Date 09-20-2009 17:50
There is only one way to deal with welding zinc coated steel from a quality, safety and economical stand point. Remove it ----- grinding or, if approved, burn it off, eliminate it from the weld zone. It can be done with E7018 ( preferred ) or E7015, E7013 ( from years ago, no longer available I believe ) or E6011. BUT the main thing here is the skill and talent of the opertator must be perfect. The zinc at arc temperatures will mostly turn to a zinc gas and at the density of the weld puddle ( all things considered ) WILL get trapped in the weld as "porosity" to various degree, again depending on the "skill and talent" of the operator. How much porosity is acceptable, is the welding going to be on heat sensitive steel, verticle up and over head (the puddle will be difficult to control and bead cross section will be hard to maintain) ????? If it is on a structural ar bridge porject, an experienced welding inspector will zero in on those welds real quick and repairs will be VERY costly and very aggravating.
Parent - - By 803056 (*****) Date 09-21-2009 23:28
Don't give away all your secrets. I can't make money if the contractors do things right. ;)

Best egards - Al
Parent - - By jrw159 (*****) Date 09-22-2009 00:05
Al,
  We have been giving away the secrets for many years but it has generally been a case of them not wanting that particular answer. :-) It is not the easy way out.

jrw159
Parent - - By 803056 (*****) Date 09-22-2009 03:58 Edited 09-22-2009 04:04
I'll give you that one, so true, so true.

I've often said, "Don't ask the question if you don't think you'll like my answer."

"The less they know the more we make" or "there is profit in ignorance, their ignorance, our profit".

I guess that is one of the reasons we spend time conversing in the Forum, so we learn from each other’s mistakes and we don't repeat them. That being the case, this meeting place is a valuable resource.

Best regards - Al
Parent - - By DaveBoyer (*****) Date 09-23-2009 02:34
Life is too short to make every mistake Yourself. :-)
Parent - By 803056 (*****) Date 09-23-2009 03:23
I was under the impression I was doing a pretty darn good job of it. I don't feel so alone now. Thanks.

Happy, happy, happy, I'm not the only screw up in the world. Wait until I tell my wife! She thinks otherwise!

Best regards - Al
Up Topic Welding Industry / Technical Discussions / 7018 weldability over zinc coating

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