1982 ASME Sec. VIII Div.1 Stress Relief Time&Temp.

[JTShoemaker]

While reviewing some records at work on some reactors in our Hydrogen unit that they may not have been Stress Relieved to the proper temperature.
The material is SA-387 Gr.11 Class 2 (1-1/4% Cr) which is a P-4 Material. Our records indicate that the vessels were stress relieved at 1100 deg F. The current code calls for a minimum temperature of 1200 deg F.
We are having trouble finding a copy of the 1980 code with the 1982 Addenda to reference to determine whether this was the acceptable temperature at the time of construction. The earliest we have been able to check is the 1989 edition. Any help in shedding some light on this would be greatly appreciated.

 

[metengr]

Keep in mind that the Code allows for reduced PWHT temperature with an increase in hold time at the lower PWHT temperature. Check all information and not just PWHT temperature.

 

[JTShoemaker]

We have factored the reduced temp and increase time factor. Unfortunately, our records do not include the duration of time at temperature. I am hesitant on making assumptions in this, but your point has been considered.

 

[weldstan]

Has this vessel been in service for 30+ years? Are you not "beating a dead horse"?

 

[JTShoemaker]

We very well could be chasing a non-issue. We are not trying to run out screaming 'The sky is falling', but there is talks of some changes in operating condition. We are just trying to cover all basis when the ball gets placed in our court. We are trying to come up with a basis to plan the extent of our inspections, if these things come to fruition.

 

[racookpe1978]

What is the service pressure and temperature?
What was service life (so far - how long have they been operating)?

For example: Service pressure = 1200 psig at 700 deg F. Lifetime = 22 years.

At that time at that high a pressure at that temperature, the vessel IS stress-relieved fully.

AT 22 psig at 150 psig for 12 years? The vessel has just sat there, the welds are as-was stress condition.

Also: What is diameter and thickness? (thinnest and thickest?)

 

[JTShoemaker]

The 4 reactors operate as follows:
Hydrotreater - 480 deg F at ~240 psig and is 5'D x .750" thick
Desulferizer A - 515 deg F at ~240 psig and is 5'6"D x .750" thick
Desulferizer B - 558 deg F at ~240 psig and is 5'6"D x .750" thick
High Temp. Shift Converter - 631 deg F and is 5'6"D x .750" thick (Due to ridiculous Process viewer that I'm allowed to access, I'm having trouble locating a pressure for this one.)

 

[weldstan]

As I recall, 1200F was the required temp when vessels were manufactured. The increased hold time, per metengr, was defined in ASME VIII, Div.1 at that time. One should assume it was performed per Code if the vessel was stamped. In the time frame of manufacture, it was also quite common to have full time supplier surveillance by the EPC firm as well as AI involvement. I know that my company would have had.

 

[JTShoemaker]

The part that really caught our attention with this is that along with a U1A we have a copy of the in-house Quality Control checklist. The AI did sign off on the U1A, but there was never an initial on the checklist for the Post-Weld Heat Treatment. This may simply be attributed to the AI not specifically witnessing the stress relief operation, and not wanting to initial for that part in particular. Not really sure on that one.

 

[pdiculous963]

JTShoemaker- I pulled my 1980 Section VIII and for P-No. 4 Table UCS-56 shows a normal holding temperature of 1100°F. I've attached the scan from the code. So it looks like the PWHT was acceptable per the Code at the time of construction.

 

[JTShoemaker]

Thank You very much for everybody's help in the matter.