Reduction in Impact test temperature for sub size specimen B31.3

[Max88]

Dear All,
I have SA 333 Gr.6 2" x 5.54mm PQR coupon supposed to be impact tested at -50Deg.C asper piping service class.

The specimen size is 10mm X 3.33 mm

So,

As per B31.3 Table 323.3.4 and Clause 323.3.4(b) , i calculated the impact test temperature as -60.3 Deg.C .Please correct me if i am wrong as my mother toungue is not english, i am having a hard time to interpret the clause

My calculations as below

Actual wall thickness = 5.54 mm
Impact Specimen Width Along Notch = 3.33

So the ratio is (3.33/5.54 ) X 100 = 60.1% which is less than 80%

Now refer Table table 323.3.4 to find the temperature reduction for 5.54mm

1. Temperature reduction for 6mm = 8.3 Deg.C
2. Temperature Reduction for 5mm = 11.1 Deg.C
3. Temperature reduction for 5.54mm = (8.3*2)/3 + (11.1*1)/3 = 9.33 Deg.C (Refer Note of table 323.3.4 Straight line interpolation for intermediate values is permitted)

Temperature reduction for 3.33mm (asper PQR Impact test specimen ) from table = 19.4 Deg.C


We have to take the difference

Ie, 19.4 - 9.33 = 10.07 Deg.C

We have to minimum this value from the actual requirement which is -50Deg.C

50+10.07 = -60.07 Deg.C

 

[SJones]

It appears to be a reasonable calculation.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.