ASME requirement related to temperature difference between PQR and product temperature for PWHT
ASME requirement related to temperature difference between PQR and product temperature for PWHT
(OP)
Hi,
Question no. 1
The PQR is qualified with PWHT according to ASME IX with a temperature at 580 deg.C, but the product was PWHT with a temperature at 620 deg.C
Is the PQR still valid accoding to ASME code since the product temperature is 30 deg. C higher then temperature for qualification(PQR)?
(The base metal is Carbon steel according to P-no 1)
Question no.2
Another PQR is qualified with a holding time at 5h, but the product was PWHT with a holding time at 7h
Is the PQR still valid?
Hope someone could help me to get answer on this two question with a good explanation, and in addition also inform me where in ASME code this information is to find.
Thanks in advance!
Question no. 1
The PQR is qualified with PWHT according to ASME IX with a temperature at 580 deg.C, but the product was PWHT with a temperature at 620 deg.C
Is the PQR still valid accoding to ASME code since the product temperature is 30 deg. C higher then temperature for qualification(PQR)?
(The base metal is Carbon steel according to P-no 1)
Question no.2
Another PQR is qualified with a holding time at 5h, but the product was PWHT with a holding time at 7h
Is the PQR still valid?
Hope someone could help me to get answer on this two question with a good explanation, and in addition also inform me where in ASME code this information is to find.
Thanks in advance!





RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
Yes, when the PWHT temperature is recorded on the PQR and it is below the lower transformation temperature you can specify a range for the WPS. The PWHT temperature range is good from the minimum of the specified range to the lower transformation temperature of the base material.
Review QW-407.1 in Section IX.
It depends on the welding process and qualification with impact testing. Review QW-250 and look at QW-407.2 and QW-407.10
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
Question no.1
In the WPS they have specify a range with 580+/-10 deg.C,and not a range from 580 - 620 deg.C
If I understand you correct you mean that the PQR is still valid as long as the PWHT temperature is below the lower transformation temperature A1(723 deg.C), but is the WPS valid?
In this case the customer have ask the supplier to start with a new PQR qualification with a temperature at 620 deg.C to disprove that the increase of PWHT temperature from 580 to 620 deg. C not give impact for the mechanical properties. From what I know there will be a litte drop in the yield strength if the temperature increase.
Question no. 2
In this case the welding process is made by GMAW, and with impact testing.
For QW-407.10 I could not find any information for this in ASME IX, and is it like this this that you take the holding time you have use in the PQR and multiply with 1,25 to see what is the max. holding time for the product compare with PQR holding time?
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
They should revise the WPS only, not re-qualify, to reflect a broader range of PWHT temperature provided it is not an essential variable change or if impact qualification is not a supplementary essential variable change.
Q2;Based on the process and impact testing you stated above, only QW-407.1,QW-407.2 and QW-407.4 apply for changes to PWHT. Go back and review these and determine the answer to Q2. Hint look at QW-407.2 for PWHT time and temperature ranges.
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
QW-407.2 A change in the postweld heat treatment
(see QW-407.1) temperature and time range
The procedure qualification test shall be subjected to
PWHT essentially equivalent to that encountered in the
fabrication of production welds, including at least 80% of
the aggregate times at temperature(s). The PWHT total
time(s) at temperature(s) may be applied in one heating
cycle.
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT
RE: ASME requirement related to temperature difference between PQR and product temperature for PWHT