×
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

Tensile test failure

Tensile test failure

Tensile test failure

(OP)
Looking at a test report on a SA387 gr. 22 cl 2 weld coupon that passed the side bend tests, but failed both tensile tests in the base metal by 10% (ASME QW-153.1(d) only allows 5% below min tensile).  Before testing, coupon was normalized @ 1650 deg F for 2 hours, tempered @ 1250 deg F for 2 hours.  Have never seen this kind of failure before, and would like any thoughts on what could have caused this.  

RE: Tensile test failure

weldgal;
What is the plate thickness? Also, do you have a MTR on the plate material (chemistry)?

RE: Tensile test failure

(OP)
Coupon thickness is 1 1/2".  We have MTRs from the supplier.

RE: Tensile test failure

weldgal;
On occasion, having qualified various welding procedures on Cr-Mo plates I have seen where the normalization heat treatment did not result in a ferrite/pearlite/bainite microstructure to meet A 387 Grade 22 mechanical property requirements. The cooling rate for plates greater than 1.25" thickness, during normalizing, is absolutely critical to achieve the desired microstructure (minimum level of retained bainite) that will provide sufficient margin to meet minimum strength requirements after tempering.

In your situation without knowing the specific chemical composition and subsequent carbon equivalent of the plate material, I would suspect the cooling rate after the 1650 deg F austenitization was too low.

RE: Tensile test failure

(OP)
According to the lab's report, they used a rise and fall rate of 300 deg F per hour above 600 deg F.

RE: Tensile test failure

weldgal;
This appears to be the problem. The rapid cooling rate necessary for a normalization heat treatment does not follow typical ramp up or cool down rates specified by the Code (like ASME B&PV Code) for PWHT. The cooling rate for a proper normalization heat treatment is optimized based on plate thickness and size to assure uniform thru thickness rapid cooling. The plate should have been cooled at a high rate after removing it from the furnace at 1650 deg F.

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