387 Gr. 11 is assigned to the A curve for impact exemption?

[John121]

the way I interpret UCS-66, SA387 Gr. 11 is assigned to the A curve for impact exemption. Some pressure vessel fabricators have been interpreting UCS-66 as saying that this should be on the 'B' curve. Are they right?

 

[SnTMan]

John121, SA-387 11 is not specifically listed for other Curves, so it would be a Curve A material. EXCEPT: If it is produced to fine grain practice and normalized it can be assigned Curve B, per note 2(b).

Specification SA-387 permits normalized heat treat but is silent on grain size except for Grade material which is coarse grain.

Note I am reading from older Editions of Sec VIII, Div 1 and Sec II, Part D.

My practice when designing with SA-387 11 was to treat it as Curve A material since I had no way of knowing the grain size and heat treat of the purchased material. I'd say if you knew the condition of the furnised material you could treat is as Curve B.

Regards,

Mike



The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[John121]

Thanks Mikes. Fabrication vendor is confirmed that material is fine grains and normalized so they using Curve B