Imact testing at -50 Deg. F and subsize specimens to ASME Sec. VIII

[Cloya14]

All,

I am having issues deciding on how to destructively test some procedure qualifications that i am trying to do. The tests consist of a P1 Group 1 to P1 Group 2 .375" thickness and another plate test of the same materials thats .750" thickness. Im having trouble deciding if ill need to lower my temperature for the .375" test coupon because im not really understanding the interpretation of the requirments of UG-84. Anybody who has some insight would be great. Thanks everyone.

 

[WE17]

Hi Cloya 14,

I am not expert in this, but may be i can share a little bit. Since you work for ASME, you need to see also Table 4.15 AWS D1.1 and B31.3 Table 323.3.4 and your construction code Table UG-84.2. you need to read carefully UG-84 Clause.
I give you an example :
you have PQR :
1. 10 mm THK
2. 8.5 mm subsize to 8 mm THK
3. 7 mm and subsize to 5 mm THK
Let say Acceptance criteria 27 Joule and MDMT -20

please see note b paragraph 2 (where the largest possible test speciment bla bla...not less than 80% of Nominal Thickness )
no 1 and no 2 no need Reduction temperature and acceptance criteria but no 3, please see calculation below :
3. Reduction temperature 11-4 (table UG-84.2) 7 (-7)
So -20-7 = -27 (reduction temperature)
YOu need also consider for acceptance criteria 27 Joule, so 5/10 x 27 = 13.5 ( so this is the acceptance criteria now )

Cloya, This is my interpretation but many people do not agree with me, so let see another expert to provide a better answer ?

Thanks n regards

we17

 

[weldstan]

You do not need to reduce the temperature for the .375" wall coupon unless the size of the impact specimen is less than 80% of .375" (.300").

 

[WE17]

Dear Weldstan

Please advice, are you agree to reduce acceptance criteria for any reduction temperature ? some people agree not to reduce the acceptance
criteria ?

Thanks n Regards

AP

 

[weldstan]

The acceptable absorbed energy values are reduced by multiplying the required minimum value by the ratio of the actual subsize specimen width along the notch to the width of a full size specimen. Ref. ASME VIII, Div.1 UG-84 (4)(a)& ASME B31.3 Table 323.3.5 Note 2.