Welding Galvanized pipe...

By Nathan Date 01-12-2011 23:35

Hello all,

I am rather new to welding and am doing some research on what are the best welding practices for welding galvanized pipe with a thickness of about .040"-.080" thick. After completing a weld joint there is a yellow whiteish residue left at the toes of the weld and around the perimeter of the weld. I understand that this is a zinc oxide film left from the vaporization of the galvanized layer. So with that said, have any of you had sucess with any ceratin gas mixture or paramters for short-arc welding this type of work? Thank you in advance for any comments or recommendations!

Nathan

By Lawrence (*****)

Date 01-13-2011 00:12

Welcome to the forum Nathan.

1. Remove the galvanized coating prior to making the weld

2. ER70S-3 is superior to ER70S-6 which has higher Si content and is prone to cracking when welding galvenized. 200 ipm 17.5 Volts with .030 filler may be better than .035 when it comes to heat control on the thinner sections.

If you are going to insist on welding directly on the coating, than you might as well use 100% CO2... The increased active gas will burn more of the coating... Spatter may increase but it's going to look like crap if you short circuit over the galvanize anyhow.

You might experiment with a drag angle rather than a push, this may reduce porosity, it will increase penetration, which may or may not be a good thing with the material thicknesses you describe.

Edit:
Keep your face out of the smoke plume... Galvanized fumes will make you sick.

By Platinumbased (**)

Date 01-13-2011 01:38 Edited 01-13-2011 01:43

http://en.wikipedia.org/wiki/Metal_fume_fever

Metal Fume Fever. You'll think you're going to die when you get a good dose of Zinc fumes.
I was working outside burning and welding on galvanized pipe stantions and got so sick I couldn't even sleep.
If you weld on zinc indoors, you're going to get sick.

Wear proper PPE and ventilate.

By joe pirie (***)

Date 01-13-2011 02:18

i've always been told to drink milk when welding galvanized material. im not sure if it's just an old wives tale

By 803056

Date 01-13-2011 03:00

It does wonders for the fumes you swallow.

Let it sink in, wait for it...............

Al

By 99205

Date 01-13-2011 05:52

Stay out of those galvanize fumes. I've gotten welders flu more than once from that crap.

By DaveBoyer (*****)

Date 01-13-2011 04:45

Here is a link to a guy who DID DIE as a result of metal fume fever. He had prior health issues, but the fume fever set off an unfortunate chain of events.

http://www.anvilfire.com/iForge/tutor/safety3/index.htm