ASME requirement related to temperature difference between PQR and product temperature for PWHT 2

The way these are worded the questions almost sound like course-work type questions. As clearly stated, student posting is not allowed. Could you provide some more background on why you're asking?

The two question is not a student posting but a real case related to our sub-supplier that have do this two thing that is not according to the PQR and WPS, and then ask this question if someone could tell me if this is accepted according to ASME code or not?

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 according 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)

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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.

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?

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It depends on the welding process and qualification with impact testing. Review QW-250 and look at QW-407.2 and QW-407.10

Thanks for your answer metengr.

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?

Q1; I don't understand why such a tight PWHT temperature tolerance was given in the WPS. Do you realize that for ASME code application, PWHT temperatures are given as a minimum AND as long as you do not cross the lower transformation temperature, a temperature range is acceptable? Why? Because the code requires a minimum strength and minimum elongation for application, and PWHT performed between the minimum in code and below the lower transformation temperature at a will achieve both.

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.

Read below
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.

Also depends on the applicable Construction Code; e.g., per ASME B31.3, 331.1(b) "Heat treament to be used after production welding shall be specified in the WPS and shall be used in qualifying the procedure." It is noted that the 580 C (1076 F) PWHT is less than that permitted under Table 331.1.1. Also review 328.2.1 (c).

Thanks for your information, and customer have accept that the supplier don't need to qualify for a new PQR or make a test with PWHT temp. at 620 deg.C to prove the mechanical properties.