Re - Normalizing Sec VIII - 1 Interpretation

[weldtek]

I found two interpretations in the latest volume ( 63 ) that pertain to normalizing P1 material, interesting. The interpretations are VIII-1-15-06 and 08.

06 Q- If a plate is normalized once at the mill and then is subsequently normalized again during manufacturing, does UCS 85 (c) require test specimens that account for both normalization cycles?
R - Yes
Q2 - In this instance, does the Code require a separate set of test specimens that represent only the first normalization?
R - No

08 Q - Consider a vessel that will have the heads fabricated from SA 516 plate normalized at the mill. During fabrication, the heads will subsequently be normalized after forming and the entire vessel postweld heat treated at a temperature below the lower transformation temperature. Does UCS 85(c) require that the test specimens for the head material account for both cycles of normalization?
R- Yes
Q2 In accordance with UCS 85(f), do the test specimens also have to be subjected to the PWHT condition for the vessel?
R - No.

For fellow fabricators, I'm interested to know whether or not, for you, this is a departure from past practice?
For metallurgists, I'm interested in your opinion as to whether or not representing the second normalizing cycle is justified?

Thanks

 

[metengr]

As a metallurgist involved with Codes and Standards for years the second normalization is critical because this is the final heat treatment. Any secondary thermal treatment cycle that effects the bulk properties, like re-normalization, must be evaluated to ensure minimum mechanical properties. A subcritical PWHT cycle does not fall under this category, because the microstructure of the plate material is not substantially altered.

 

[Fizza453]

Weldtek:

The above mentioned interpretations may not be straight forward valid in the light of UCS-85(i). Second normalization need not be accounted for if second normalization temperature is below or equal to the first normalization, I read the UCS-85(i) this way. Any comment please?


Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[metengr]

UCS-85 (i) basically states that all thermal treatments which precede a thermal treatment that fully austenitizes the material need not be accounted for by the specimen heat treatments provided the austenitizing temperature is a high as the preceding thermal treatment.

So, if the final normalizing (austenitizing and air cool heat treatment) is performed at or above previous treatments by the mill or otherwise, the last performed at or a higher temperature from preceding heat treatments re-sets the material properties.