×
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

Referee Standards in ASTM A691 & B31.1

Referee Standards in ASTM A691 & B31.1

Referee Standards in ASTM A691 & B31.1

(OP)
We've recently purchased 30" X .812" A691 1/1/4 Crome pipe from a European producer.  We're now finding that the pipe should have been manufacturered to the B31.1 requirements which have a slightly higher tempering temperature than is required by the ASTM spec--details as follows:

Post weld temp requirements:
B31.3 requires:  704-746 deg C
A691 requires:   590-745 deg C
The actual HT applied to the pipe was 650 Deg C

We've simulated the post weld re-heattreatment of pipe samples within the required HT range in a lab furnace at 715 degrees C with the following results:

UTS:

Sample 1-Transverse Weld: 540 MPA   (515 MPA min required-                                    for "Normalized" Plate)
Sample 2-     "           536               "      

         Base Metal:
Sample 1-                 504                "
Sample 2-                 507                "
Sample 3-                 497                "
Sample 4-                 506                "

YS:
          Base Metal:
Sample 1-                 304       (310 MPA Min required)
Sample 2-                 306                "

etc. etc.

QUESTION:
1)  Is there a referee standard in B31.3 or A691 (A387 for 1 1/4% Cr plate) that would provide some allowance on the UTS and YS?

2)  Is there a referee standard on the temperatures required by B31.1?

Thanks for your help--


Regards
RAvera  

RE: Referee Standards in ASTM A691 & B31.1

ravera;
ASME B31 Pressure Piping Codes do not provide specific material fabrication tempering requirements, when material is furnished under a recognized international material standard specification like ASTM or ASME.

Second, I reviewed ASME SA-691, the 1.25% Cr- 1/2% Mo alloy steel plate is supplied under SA-387. SA-387 Grade 11 plate after austenitizing is tempered at 620 deg C-745 deg C. The recommended PWHT for welded plate fabrication under SA-691 is 540 deg C - 745 deg C. The required mechanical properties have to meet the SA-387 plate specification.

For butt welding in the field, ASME B31.3 recommends a PWHT temperature range of 704 deg C to 746 deg C for P-No 4 material.

RE: Referee Standards in ASTM A691 & B31.1

(OP)
Thanks metengr.  Upon further research I see that the B31.3 HT requirements have specifically been imposed for the longitudinal weld seam by the E&C---KBR.  Don't guess I have a way to circumvent the issue since it's imposed by the client.

RE: Referee Standards in ASTM A691 & B31.1

ravera;
This raises an even more interesting issue regarding seam welded piping and PWHT. Your client should be aware that a N&T (normalize and temper) heat treatment is the best approach for any Cr-Mo long seam welded piping in elevated temperature service.

RE: Referee Standards in ASTM A691 & B31.1

(OP)
Metengr,
The pipe will be provided in the N&T condition.  The issue specifically relates to the tempering temp--B31.3 (704-746) VS A691 (590-745).  The 650 that has been applied to the tube is not acceptable.


Pls Also note:  the 540 mentioned in the orignal post was a typo!

Tks,

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