impact test joule value for sub size specimen 1

[EngrRodri]

Guys,
Need your help regarding the impact test recently done. Please be informed for the ff
1) Design Temp is -28
2) Test coupon is 12.7 mm, API 5L X60,
3) Gtaw & Smaw Process
4) SMAW Size for impact test is 10x10x55
5) Gtaw size for impact test is 2.5x10x55
6) Both are done using -28 test temperatue
7) requirement shall be minimum of 32 J per specimen
8) SMAW SPECIMEN passed for HAZ & WELD METAL. above 32 J
9) GTAW SPECIMEN is below 32J. For HAZ is 28,30,14 & for WELDMETAL - 11,20,16
QUESTION
1) Does linear interpolation allowed in JOULE, because of reduction in size for GTAW
2) Does the above data from GTAW SPECIMEN HAZ& WELDMETAL passed the requirements as per linear interpolation

 

[metengr]

What is the code of construction?

 

[EngrRodri]

B31.3 .... METENGR

 

[metengr]

Your stated information above is confusing and does not align with the impact requirements of B31.3. First, look at ASME B31.3, Note 1 in Table 323.3.4 Charpy Impact Test
Temperature Reduction. Note 1 allows for linear interpolation for intermediate values. This table is for subsize CVN specimens regardless of welding process.

Second, for subsize Charpy impact specimens, the test temperature must be reduced in accordance with Table 323.3.4 because of geometry affects - thinner specimens will exhibit higher impact energy values because of less constraint from reduced thickness.

Where did you obtain the requirement for 32 Joules? Look at Table 323.3.5 Minimum Required Charpy V-Notch Impact Values.

 

[EngrRodri]

metengr..... Thankyou for response..

as per our client standard procedure that API 5L X60 shall have impact value of 32J
and if sub size will follow B31.3

Also as per client procedure. they require separate impact test for GTAW & SMAW .... that is why the size of test specimen is 10x2.5x55

 

[EngrRodri]

Please correct if I'm wrong as per table 323.3.5 note 2.... that for sub size specimens, these value shall be multiply by the ratio of the actual specimen width to that of full size...... having 10:32 = 5:X , X will be 8.... is the minimum Joule as per my interpretation

 

[metengr]

Yes, per Note 2. However, the actual test temperature must still be reduced from -28 deg C to a lower test temperature for the subsize CVN impact specimen based on Table 323.3.4. So, you have two items - test temperature reduction for the subsize specimen and a correction for the acceptance value.

 

[weldstan]

You could impact test both processes independently, the GTAW process at 5 mm.