purging of steel pipe?

Date 08-02-2007 21:28

i read a lot of topics that mention "purging" a pipe. what exactly is purging. where and when do i need it? can i still use 100% argon? does any of this pretain to steel pipe such as EMT? thanks, you have all been so helpful with me learning how to tig correctly.

By scrappywelds (***)

Date 08-03-2007 01:04

purging is using a backing gas on the inside of the pipe. Yes 100% argon is fine. Steel pipe really doesn't need it, though it does make a nice root. Mostly stainless steel or excotic steel pipes, the purge keeps the root from "sugering" .

By fbrieden (***)

Date 08-03-2007 02:51

Previous experience and ongoing: Any CS pipe going to FILTERS on return lines, USUALY does not require back purge; although purging does allow internal weld apearance and mechanical properties to be above normal. Purging, or any other type of corrosion inhibitor applications, should be used to prevent, or minimize any type of internal loss of corrosion resistance on any type of Corrosion Resistant material(s)