×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

CRA cladded pipe welding purging gas

CRA cladded pipe welding purging gas

CRA cladded pipe welding purging gas

(OP)
Hi Peers,

I have a specification requirement that requires the purging gas to remain on until the completion of the weld.  (CRA cladded pipe weld)

Now I would concur with purging for the root and hot pass and maybe even a couple of filler runs.  But I do not understand why the gas would need to remain on for the full duration of the weld.  

I wanted to turn off the gas after about 30% (5-8 layers) of the weld was completed but unfortunately I wasn't granted this request by the specification owner.

Appreciate any feedback as to your thoughts about any benefits for keeping the internal purge on until the joint is 100% welded.

I note that AWS D10.11 clause 6.3 says that it is normal practice to maintain the purge for the 2nd and 3rd layers.

The continuous purge will have significant implications as I'm assure you already understand (cost of gas, HSE, no in-process inspection internally etc.)

Thanks in advance.

RE: CRA cladded pipe welding purging gas

Seems a little unreasonable to me too.  Might switch from argon to nitrogen after the 3rd layer and save a little $$.

However, as long as his/her checkbook is open, the customer is always right.

RE: CRA cladded pipe welding purging gas

bernoullies123;
I would concur with your approach that purging gas should not be required/needed once "x" thickness of weld is deposited.

The only technical reason I can think of for having such a specific requirement is to ensure no surface oxidation or other surface contamination of the weld region CRA cladding occurs from the heat of welding.
 

RE: CRA cladded pipe welding purging gas

(OP)
Thanks, I was hoping I wasn't alone on my thinking.  

Unfortunately since it is in the spec, we are faced with the cost and not them.  Thanks for the N2 tip, may have to investigate that one quickly, as the pallet of argon will run out quickly at 300 L/h.   

RE: CRA cladded pipe welding purging gas

Be careful here because nitrogen can be a contaminant for certain grades of CRA. Stick with welding grade Argon.

RE: CRA cladded pipe welding purging gas

(OP)
Thanks metengr.  

Spec only allows industrial grade argon (< 50 ppm O2), and noted that nitrogen will probably cause weld metal porosity in the grade of CRA.  

 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources