Welding galvanized steel to mild steel..

By dcox Date 11-28-2004 04:57

I'm looking for some help/advice. I am a novice welder (part of the problem). I'm using a GMAW welder and have had very good success welding mild steel to mild steel; in both penetration and presentation.

But I am having a very difficult time welding some mild steel to some galvanized panels on a chassis. With similiar settings and methods I use to get good welds with mild steel, I can't get anywhere when welding galvanized steel to mild steel.

I am using the same wire and gas settings, grinding some of the galvanized doesn't seem to help.

I am getting a lot of pops/spatter and a lot of porous beads. Not going well at all. Please help!

Thanks

By billvanderhoof (****)

Date 11-28-2004 06:51

Don't ignore the mild side, if you've ground off the zinc on the galvanized side and the other side has paint or grease or rust... that could contribute also.
Bill

By Northweldor (***)

Date 11-28-2004 14:00

dcox:

I recently used up some heavily galvinized angle and had similar problems, at first, and I think you still have zinc contamination. It may appear that you have ground off the zinc, but unless you cover the complete heat affected zone, you are still going to get zinc vapor boiling off and interfering with arc characteristics and causing porosity. If you notice your short-arc acting like poorly adjusted spray-arc (quiet arc and pops rather than usual steady buzz), zinc vapor is likely the cause

By dcox Date 11-28-2004 15:32

My mild is cleaned up new stock.
I'm betting I'm still getting zinc contamination, as I've only ground off my welding area, and not the heated area. I'll try to ground off more of an area.

How do I know if I have ground out all the zinc? Is all galvanized metal dipped, or is some of it a mixture process with the molten metal before it's formed?

Do I need to adjust my gas/voltage/speed when working with galvanized or would the same settings for the same thickness of mild steel work?

Is there a better wire to use for this type of applicaton?

Thanks guys.

By Lawrence (*****)

Date 11-28-2004 15:54

http://www.iza.com/zwo_org/Applications/Continuous_Galv/030609.htm

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Nice and cheap from the Aussies http://www.gaa.com.au/design4.pdf

By pipewelder_1999 (****)

Date 12-05-2004 22:54

The metal will spark like regular steel. Even then there is some left.

GA

By Pedro Coloma Date 12-05-2004 14:58

You can find a very nice article called "Welding Galvanized Steel" at www.sperkoengineering.com. According to this article , you should also check your joint design.

By dcox Date 12-05-2004 15:54

Thanks, I found this, and most likely my problem...

"The silicon in welding electrodes should not exceed 0.85%; this means that commonly used ER70S-6 filler metals should not be used
when welding galvanized steel."

Now to figure out what wire I should use in my GMAW setup.

By Lawrence (*****)

Date 12-05-2004 21:43

Take a look at:

ER70S-3

http://www.hobartbrothers.com/pdf/BR_3.pdf

By pipewelder_1999 (****)

Date 12-05-2004 22:52

Are you cleaning the zinc from both sides? You may be melting through?

Gerald

By kawgomoo (*)

Date 12-12-2004 20:16

use the lincoln wire, L50 i believe it is. it will tolerate millscale grease oil dirt and funk pretty well. and uhh for gods sake, grind off the galvanized. it releases highly toxic fumes when u burn it. galvanized metal is just plain ole base metal thats been coated with a rust inhibitor.