Hi,
S690QL is Equivalent to A517 Gr.Q ; Since this is Q&T , in general PWHT is not recommended, but Post heating as shall be applied as you stated.
But as per as concern PWHT , if it is beneficial to your service conditions you can do;
It seems to Hydropowerplant application(Penstock) , the vibration factor, & what Codes/Standards your following should decide your main requirement for the PWHT
Thanks & Regards,
K.Babu
Singapore.
2009/4/3 Erhan Turgut <erturgut@gmail.com>
Hi,
We're working on 2700 mm dia. pipes with a thickness range of 26 - 40 mm
for S500QL and 30 - 48 mm for S690QL.
These penstocks will be used in hydro power plant with a pressure of
aprx. 140 bar
We have two methods for welding: SAW on GTAW (root GTAW, fill & cap SAW)
and SMAW on GTAW. We will try to achieve max. 12 kJ/cm heat input.
So shall we apply PWHT (Stress relief)? If yes what is the thickness
limits for PWHT.
We planned to apply Soaking (Hydrogen Releasing) with a temperature of
aprx 250 oC for 2.5 - 3 hours. So if we apply Stress relief
heat-treatment with a temp. of 550 oC for 1 hour do we have to apply
soaking anyway?
Thanks in advance
Regards,
Erhan TURGUT
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