[MW:29142] Re: Backing gas as per API RP 582

To answer your question, using the SMAW process back purging is not required. If you are welding SS pipe with an open root

and desire complete penetration & visually acceptable, you should weld the root & 2nd pass with the GTAW, (TIG) process. This 

process requires back purging with an inert gas such as Argon to protect the root from oxidation. This back purge is left 'ON' through the 2nd. pass. Depending on your WPS you can complete the weld using GTAW or SMAW. We generally weld SS pipe from the root thru the cap with GTAW and a back purge. Their is also TIG wire available which has a special coating on it which will act as back purge & you do not have to back purge with Argon. 

Again, the SMAW process doe not require back purging. One can weld an open root with the SMAW process, however; the root will not have complete penetration

and the root will be oxidized.

On Sunday, January 27, 2019 at 8:33:27 PM UTC-6, John Manoj wrote:

Dear Experts,

As per clause 7.3 of API RP 582 Ed. 2016 back purging required for GTAW & GMAW process but no where I could found for other process like SMAW.  Is it mean that if we do welding with SMAW process back purging is not required?

Please share your interpretation.

Thanks and regards

Manoj.

--
https://materials-welding.blogspot.com/
https://www.linkedin.com/groups/122787
---
You received this message because you are subscribed to the Google Groups "Materials & Welding" group.
To unsubscribe from this group and stop receiving emails from it, send an email to materials-welding+unsubscribe@googlegroups.com.
Visit this group at https://groups.google.com/group/materials-welding.
For more options, visit https://groups.google.com/d/optout.