ASTM A36 MDMT for 35 psi pneumatic tank

[wijaya1]

Could anybody tell me the MDMT of ASTM A36 steel for designing 35 psi MAWP pneumatic tank? Based on discussion of Sam Cheung et al, I am under the impression that as per ASME COde Sec VIII, Fig UCS 66 M, the minimum temperature recommended without the need to conduct Impact test is +20 deg. F or -7 deg. C.
Someother information I received from steel supplier is not to be used below 5 deg. C.
Any shed of light on this matter is much appreciated

 

[metengr]

If this pneumatic tank is built to ASME B&PV Code, Section VIII< Div 1, you cannot use ASTM A 36 outright. The material should be certified to ASME SA 36. Once this is completed, the requirements of UCS-6 would apply for using SA 36 plate material, which by the way is limited to 5/8" or less.

Regarding MDMT, this information can be found in Figure UCS-66, and unfortunately, your MDMT is limited to Curve A in Figure UCS-66, which for the 5/8" maximum thickness limit would be right around 38 deg F w/o impact testing, and 20 deg F for material thickness less than 0.394".

 

[wijaya1]

Thank you Sir for your prompt reply. There was a string of email back in May 2005 in the same forum that says :"Per the 2003 Addendum SA36 is identical to ASTM A36/A36M-00a".

And another one says :"They have the same chemistry and properties, but there may be differences in testing and documentation.They are not interchangable.
In many businesses virtually all material is dual certified to the ASTM/ASME standards. "

Can you please clarify the difference between the straight ASTM A36 and ASME SA 36?

Many thanks.

 

[metengr]

You need to review the ASME material specification - SA 36. The material may be dual certified, however, they are not interchangeable specifications. If you are building this vessel to ASME Code, you must have have access to the appropiate material specification(s).

 

[vesselfab]

listen to what people are telling you

it is identical up to a point.

De-coiled plate (which much of if is in the thickness you are contemplating) is not treated the same and is exempt from the "identical" rules until the decoil processor levels, squares, and recertifys the material.

that being said, a-36 is really a structural plate with poor grain structure, poor manufacturing methods, and really should not be used for a pressure vessel. Look at the heading description in Section II

the energy, even at 35 psi, stored in a compressed air vessel can kill, and that should be a major concern.

there is no real cost differential in a-36 up to a "real" pressure vessel quality plate

 

[SnTMan]

wijaya1, it appears to me that, for Sec VIII, Div. 1 work, SA-36 may be assigned an MDMT of -20 F., if meeting all the requirements of UG-20(f). In this case your thickness would be limited to 1/2", which, I would think, would be sufficient for a 35 psi vessel, if not "too" large.

Having said that I agree that SA-516 would be a MUCH better choice.

Regards,

Mike

 

[wijaya1]

Thank you for all the valuable responses and feedbacks.

 

[JStephen]

Seems like most of the A36 plate we see is shown as ASTM A36/ SA 36/ A709 (I think that's a bridge spec). Look on the mill test reports or ask the supplier.