Div 2 - Test Specimen Heat Treatment - P5A

[weldtek]

I'm having some difficulty in understanding the requirements for the heat treatment of test specimens as discussed in Par 3.4.3. Condition A is to be the actual Max temp - 25 F and 80% of the hold time. Condition B is actual minimum temperature + 25 F and 120% of hold time. For PWHT, I normally specify a maximum temperature spread of +/- 25 F, but it appears that that would put the temperature for both conditions at 1250 F. Can somebody tell me what I'm missing?
(Per Table 6.11 PWHT temperature for P5A is 1250 F and required holding time is 1 hr/in.)

Thanks,

 

[metengr]

weldtek;
I have Div 2 in front of me and read 3.4.3.1 and 3.4.3.2. I don't see a problem. The Condition A and Condition B requirements were based on either past experience or current limitations of the heat treatment furnace. In other words, having a furnace survey should be performed to ensure accurate PWHT exposure and to confirm the exposure ranges as stated also see Figure 3.1.

 

[metengr]

weldtek;
Let me re-state above in this manner - the purpose for 3.4 is to ensure that the furnace used for heat treatment for certain Cr-Mo materials, as defined by Table 3.1 are evaluated by temperature and time boundaries. For example you decide to have a thermal treatment range of 1250 deg F min to 1325 deg F maximum, and hold time is determined to be 2 hours. The purpose of 3.4 is to now evaluate actual test material under the following bounded conditions - min temp +25 deg F, max temp -25 deg F, hold time min at 0.8 of 2 hours and maximum hold time at 1.2 x 2 hours. The mechanical test results bound these conditions to ensure you do not alter bulk properties. PWHT would be performed within the above, as required by 6.4.2.

 

[weldtek]

Metenger,
OK thanks. I was thinking we'd hold a tighter temperature range but I can see the wisdom in qualifying material with a broader temperature / time range.