High Temperature Tensile Test at temp higher than ASME II-D

[SJmetallurgist]

Hello

I am required to do a high temperature tensile test on plate material SA387 Grade 11 Class 2.
The design temperature at which I am required to do the test is 549 deg. C. I have chosen 550 deg. C as nearest round up.

As such, ASME Section IID provides high temp tensile and yield strength values only upto 525 deg. C max.

My vendor has already shaken his shoulders based on above fact and is now asking me to provide a value for acceptance.

Do I interpolate the allowable stress value of 550 deg. C of table 1A as per mandatory appendix 1 of ASME Sec II-D?

Any help would be much appreciated. Thanks.

 

[metengr]

First, you are being asked to conduct an elevated temperature tensile test. This has to be done to determine actual tensile strength and yield strength values at 550 deg C. What is the problem? The tensile test will provide mechanical property data.

The allowable stress values in Table 1A are established based on time independent and dependent evaluations. At the temperature you are concerned with time dependent regime applies and creep or lower yield may govern, whichever is lowest.

 

[SJmetallurgist]

Thanks Metengr. I understood about entering time dependent regime when assessing high temp. tensile strength.
My specific difficulty is further elaborated as under:
1. I need the acceptance criterion for the observed values of high temperature tensile strength.
2. II-D does not provide the values at the temp of 550 (max temp is 525degC till which the values are provided).


Question: The values which would be obtained in high temp at 550degC. Would it be just for information or should I use a proper acceptance criterion for comparing the results? In case an acceptance criterion should be there, what should be the values of that acceptance criterion?

 

[TGS4]

Just who is requiring you to do this test? Perhaps these are questions to be asked of them?

From my perspective, such information would be for information only. There are no requirements for such test, nor any acceptance criteria.

 

[SJmetallurgist]

I read another thread on almost the same topic, thread794-140281
I understand that the general opinion is to keep the values for information, un-till there a large deviation from the code values.
For this case I am using strength values at 525 deg.C. Will watch how the test results come.
My next course (for academic interests) would be to read further literature on what evaluations/investigations could be done in case of significant deviations.

 

[Josep Maria Perdigo]

ASME IID Table 1A gives the allowable stress value at 550ºC (italic = time dependent). Table 1-100 gives the criteria for setting allowable stress value. From there maybe you can establish an acceptance criteria for your test.