Post weld heat treatment for ASTM A213 Gr. T91, T22 & T11 common heat treatment temperature

[Arun George]

Dear Team,
I have to weld a combination of materials as mentioned below.
1. ASTM A213 T11 to T22 (ASME Section IX P No. 4 to P5A)
2. ASTM A213 T22 to T22 (P No. 5A to 5A)
3. ASTM A213 T22 to T91 (P No. 5A to P15E)

Can anyone suggest a suitable PWHT temperature which can allow furnace heating of all combinations together.

 

[EdStainless]

Do you have WPSs? What do they list for allowed PWHT?
What are the upper and lower limits in the Code for each grade?

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P.E. Metallurgy, consulting work welcomed

 

[Arun George]

Hi Edstainless,
I have to qualify WPS for these combination since i didn't have the particular match. Please see the attached PWHT recommendation, there it is identified in yellow color for lower critical temperature for each material and PWHT minimum & maximum ranges. So, I got confused to follow a common temperature for all material to stress relieved together. Appreciate your suggestions if any.

 

[EdStainless]

So while in theory you could use 1300-1350F, would the lower strength materials still meet acceptable mechanical properties after that?
Sound like you need to take some coupons in the original condition and then give them a simulated PWHT at the max time expected (and using coupons that are thin as you expect to see in the unit) using the temp that you select.
Then test properties of each to see if they are acceptable.
Hardness requirements for some of the alloys and welds may push you to use a slightly hotter temperature.
This may take a few teats.
If so then weld up coupons and go at it.
The real problem is that if you end up saying that 1300-1350F is the temp then holding that range will be critical and may not be possible.
Explore what temperature range you can control for the entire unit also.

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P.E. Metallurgy, consulting work welcomed

 

[davefitz]

Be sure to follow the guidelines of AWS D10.10 ( 2021) for placement of monitoring thermocouples , distance from induction heating elements to weld zone, and ramp-up temperature ramp rates. According to field test data from Superheat , inc, it is easy to overheat the zone between the monigoring thermocouples and the heating elements if the ramp up rate is too fast, and that rate should decrease by the square of the distance between the t/c's and the heating elements.


"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[Dhurjati Sen]

Simply not possible to heat all combinations together at a particular temperature.

Need to perform PQR again to get required WPS.

DHURJATI SEN
Kolkata, India