Problem with para 323.3.4b

[AliGrailly]

Hi


Less than 80%
be conducted at a temperature lower than the design minimum temperature by an amount equal to the difference (referring to Table 323.3.4) between the temperature reduction corresponding to the actual material thickness and the temperature reduction corresponding to the Charpy specimen width actually tested.


Base Metal = 8 mm
Obtainable Specimen = 3 mm
80% of 8mm = 4mm
So 3mm less than of 80%

If code required impact temp -50C
the obtainable specinen should be tested at -77.2C? Or i did not understand what this para stated.
Ref to table 323.3.4 3mm ... 22.2c temp reduction

 

Your free-of-charge answer is: Yes, No, or Maybe.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[weldstan]

80% of 8 mm = 6.4 mm. You will have to decrease the impact test temp.with the coupon being only 3 mm. By how much is up to your calcs/interpretation from B31.3.

One must ask, why you don't qualify on plate samples? It is permitted by Code but maybe not your contract, I assume.
I will state that we had no problem with similar samples tested at -70 and a few degrees lower with GTAW process and ER70S-2 filler.

 

[BenMacier]

Following up on weldstan's answer, the relevance of testing a 3mm high charpy sample is highly arguable on how the result will be meaningful regarding fracture resistance of the material.

There are other fracture mechanics tests that could be more appropriate and meaningful in your case, while still being code compliant.

* Finding a solution is great * Knowing how to implement it is fantastic * Believing it is the only one and best is naive ?