We need to know way of calculation temperature reduction when we use sub size specimen.
We have tested an A333 Gr.6 (4" pipe-6.3 mm thickness). Laboratory used a sub size specimen (55*5*10). and tested it at -48c. test temperature of A 333 Gr.6 is -45C (3 degree Celsius cooler temperature) Unfortunately absorbed energy was low and the test was failed. We see a clause in standard (SA-333/SA-333M) which described that:
" 14.1.2) When sub size Charpy impact specimens are used and the width along the notch is less than 80% of the actual wall thickness of the original material "
Is this clause applicable for this case??????
Really we don't know which one is correct?
- (5/6.3) * 100 = 79% then we should not apply the above mentioned clause and we shall calculate reduction temperature and test my sample in cooler temperature(-45 + -3 = -48).
- (10/6.3) * 100 = 159% then we should not apply the above mentioned clause and no need to reduction temperature and test my sample in MDMT(-45).