UCS 65 Lowest Impact Test Temperature 3

[Angsi2]

Code: ASME VIII Div I


Will I be correct in saying the lowest impact test temperature I can subject A516 Gr70 plate to is -105 degC?

Thanks in advance.

 

[bernoullies123]

UG-84(b)(2) indicates that the test temperature must not be higher than the MDMT, therefore they do not indicate at what temperture a test is to be performed as long as the impact energy is satisfied in Fig. UG-84.1.

As an example discussed by K.R. Rao in the Companion guide (viewable in goggle books) pg 74. Example: MDMT is 30F and the vessel is subject to a decrease in temperature due to the stress ratio of 100F, therefore the allowable operating temp is -70F, but this is below the mandatory impact test temp. of -55F. So impact testing is required, but only at 30F, and the vessel is safe for -70F. (This was clarified in Intrepretation: V111-1-89-268).

 

[bhushan76]

SA 516 Gr.70 plates would not impact tested to this low temperature. Vessel having MDMT of -105 Deg C will not be of SA 516 Gr 70 plate.

Have a look at SA-20 which gives generally available thickness and minimum test temperature combinations meeting charpy V- notch impact requirements.

 

[metengr]

Will I be correct in saying the lowest impact test temperature I can subject A516 Gr70 plate to is -105 degC?

No, this statement makes no sense because you have no mention of MDMT and thickness. Go back and review UCS-66.

 

[Angsi2]

Metengr,

Assume MDMT -105 degC.

Bushan76,

I know this is extreme cold temperature, but the question is, can 516, 70 be used or allowed for this purpose subjected to acceptance of impact test.


Thanks in advance.

 

[EngAddict]

Sure, if it can pass the impact test (which it won't).

 

[SJones]

thread794-259202

Steve Jones
Materials & Corrosion Engineer

http://www.oilandgaspeople.com/cv/11499664

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