Hi All,

I am trying to use carbon steel material that is certified as ASTM A108-1018 on a Section VIII Div 1 vessel.  I've checked out thread330-288829: Is A-108 grade 1018 round bar a recognized ma by ASME (SA designation) and found some good info there.  The material certification I have only lists A108 and A29 in terms of specifications.  Section II doesn't contain SA-108 and SA-29 doesn't list mechanical properties - it's mainly tolerances.

My material supplier can't find any 1018 which lists A105 or A696 on the certification.  What are some other materials that are similar to 1018 and are commonly available with a ASME certification?  Alternatively, can I send out some of the 1018 for testing and certify it myself?  What would be the process for this?  I am looking for 3" diameter round bar.

Any help would be greatly appreciated!

Best,
Steris

ASME Section II-A SA-311/SA-311M 2010 Edition Table 1 lists A 108 under its referenced documents.

What part of the vessel will this material become?  In general, support structures (nonpressure parts) need only be proven to be of "weldable quality" (Ref. UG-4(b))

Hi Fegenbush,

Thanks for the info.  This part will be used as a crucial part of the locking mechanism for a quick actuating closure.  It does not see the pressure from inside the vessel directly but it is subject to stress caused by the pressure.

In general, can I use material that conforms to A108 if it meets the requirements of SA-311?  It would have to match the chemical and mechanical properties required for SA-311.  What is the process for self certifying material?

If you have the paperwork to show it conforms to SA-311, I wouldn't think that you should have any problem.  Also, be advised that Section II-D does not contain design stress at temperature info for SA-311, so you may need to find alternate reliable sources for that information.  If your maximum temperature is 32°F-650°F, I would say that you would be fine with ambient data (Ref. Section II-D Table 1A, SA-36).  When in doubt, call the AI, since they will be the one signing off on it.

Might be a lot easier to use SA-516 Grade 50, 55, or 60 instead of 1018.  As the "SA" denotes, this material is accepted by ASME for use in pressure fabrication and had Temperature vs. Stress data listed in Sect IID.  Your A.I. will have no qualms about signing off on SA-516 material.

Duwe6,

SA-516 is a plate spec.  While I would agree that to cut flat bar from plate would be best, Steris says that he is looking for round bar.

If we're talking about changing materials, SA-36 would be acceptable, but that usually leads to large diameters due to the low yield strength.

If I understand correctly, you have the A108 1018 material and cannot find material data to use.  ASME 2007 Code Cases gives Sy and Su for this material up to 400 F.

If you can extrapolate, and need to, a nice way to do it is scale the A36 curve, which is in Section II, Part D up to 1000 F, and which over the 0-400F range has about the same shape as the A108 1018 curve.  Just scale the A36 curve to match the A108 curve.

I don't know whether you are allowed to do that.  If you simply use the A36 curve, you are conservative.

Ultimate strength is listed in the code case as 60 ksi, constant, 0F-400F.