Heat input at wps/pqr 2

[migias]

ASME IX at QW-409.1 writes that "...heat input does not apply when the WPS is qualified with a PWHT above the upper transformaation temperature..."
What do they mean upper transformaation temperature?
Is it the solidus of the phase diagram of the base metal?
In general if PWHT is used Heat Input is applied or not?

 

[stanweld]

The upper critical temperature is that temperature at which ferritic steels completly transform to an austenitic microstructure. The welding heat input paramters do not affect toughness when the the weld is subject to a fully austenitizing heat treatment - the austenitizing heat treatment temperature and cooling rate there from principally affect toughness along with the chemistry of the alloy steel.

 

[DVWE]

In general if PWHT is used Heat Input is applied or not?

Heat input is a supplementary essential variable when impact testing is required by code. Regardless of whether or not PWHT is required.

Heat input would not be of concern when impact testing is required if the welds receive an austenitizing heat treatment because it is returning the heat affected zones to a "homogeneous" state, not just a post weld heat treated or stress relieved state.

 

[migias]

If I understand right, In the case that impact test is required, or in general, and the PWHT is at austenitizing temperature, then Heat input measurement is not mandatory. As I can see for example in ASME VIII table UCS-56 (PWHT for P-No 1) the temperature is bellow the austenitizing one. So heat input measurement is required. Is this correct?

 

[stanweld]

Yes

 

[migias]

Thanx for helping

 

[DVWE]

migias,

Are you qualifying your WPS with impact testing?

I believe you are also qualifying with PWHT below austenitizing temperature, correct?

 

[migias]

Thats correct

 

[DVWE]

OK. Then heat input control is required if you are impact testing.

IF you were impact testing AND PWHT above the austenitizing temperature, then heat input control would not be required.

Hope that helps.