ASME IX PWHT
ASME IX PWHT
(OP)
When the code (section QW 403.6) specifies this clause does not apply when a WPS is qualified with a PWHT above the upper transformation temperature, what temperature is it referring to? I assumed that this upper temperature was the quenching temperature? The reason I ask is I am looking for the clause in ASME that allows you to, for example, qualify on 19mm and weld down to 4.76mm if you use PWHT.





RE: ASME IX PWHT
RE: ASME IX PWHT
RE: ASME IX PWHT
RE: ASME IX PWHT
RE: ASME IX PWHT
RE: ASME IX PWHT
RE: ASME IX PWHT
Basically, the lower transformation temperature is the temperature at which some of the Ferrite starts to change into Austinite (In transformable steels of course). The upper transformation temperature is the point where all the change (from ferrite to austenite)is done. The temperature range between these temperatures is called intercritical. (That would be QW-407.1(5)) As examples, on low carbon steel, a typical lower transformation temperature (Also called the Ac1 temperature) could be about 1300F. A typical upper transformation temperature (Also called the Ac3 temperature) could be about 1550F.