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!

*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

PWHT maximum soaking time?

PWHT maximum soaking time?

PWHT maximum soaking time?

Is there any limit for maximum soaking time during PWHT as per construction code or Metallurgy.
Say example LTCS P number:1, A333., construction code B31.3 process piping.
There is minimum soaking time limit as per construction code , but what about any maximum any limit on maximum soaking time?
Replies continue below

Recommended for you

RE: PWHT maximum soaking time?

No limit
See ASME B31.3 2020


RE: PWHT maximum soaking time?

Limited by welding procedure qualification time when impact test qualification required per ASME IX.

RE: PWHT maximum soaking time?

Agree there is no limit per code, unless impact tested.

Maximum soak time is typically addressed in a PWHT procedure, usually specified as an exact time with limits.

Example: SA-333 Gr 6, 6" STD, PWHT for 1 hour +15/-0 minutes

The devil is in the details; she also wears prada.

RE: PWHT maximum soaking time?

IMO it is limited by Engineering Judgment, which is mandatory in the ASME Code. Besides, more PWHT time costs.
The highest I have seen is 20 hours for nuclear steam generator pressure boundary material. The justification is to qualify multiple weld repair and re-PWHT events that might happen in future.
I can't think of other pressure equipment that could require anything near that time.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: PWHT maximum soaking time?

Please, can you check "Example: SA-333 Gr 6, 6" STD, PWHT for 1 hour +15/-0 minutes" ?

NPS 6 STD t= 0,28"
Table 331.1.1 says 1 h/25 mm (1 hr/in.); 15 min min.
This represent a linear ratio, then holding time is 17 minutes

Also I see that table 331.1.1 says P-No. 1, Group Nos. 1–3 , (and group 6 ?). This is an error because it does not match the ASME IX tables. I don't know what happened at ASME.


RE: PWHT maximum soaking time?


My post was only meant to show an example of a maximum PWHT time as I’ve seen them in production and in various PWHT procedures.

I see a lot of customer specifications and other industry practices that require 1 hour minimum PWHT time for carbon steel materials and my example was also based on that. So in other terms: “1 hour minimum, 1 hour and 15 minutes maximum”. This gives the furnace operators a viable range to work with.

Also note in my example “Gr” means “grade” in this case, not to be confused with “group” as listed in ASME IX. SA-333 Grade 6. It’s quite a commonly used material in the pipe fabricating industry.

The devil is in the details; she also wears prada.

RE: PWHT maximum soaking time?

Forgot to see APPENDIX A in B31.3
My apologies.
Thank you !


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! Already a Member? Login


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close