PWHT maximum soaking time?

[Gokul Vijay]

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?

 

[r6155]

No limit
See ASME B31.3 2020

Regards

 

[weldstan]

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

 

[DVWE]

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.

 

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."

 

[r6155]

@ DVWE
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.

Regards

 

[DVWE]

r6155,

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.

 

[r6155]

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

Regards