We are modifying old existing 2.25 Cr 1 Mo A335 P22 (Desuperheater ) piping to incorporate a new type of desuperheater. The new piping material comply with Jfactor <100 requirement. We are not sure whether the old material complies.
My query is can we determine how much extend temper...
Have a query.
What is the DBTT-Ductile Brittle transition temperature for 2 1/4 Cr-1 Mo -P22/F22 chrome moly material?
Is there a formula for calculating this DBTT?
Is this DBTT valve fixed for all 2 1/4 Cr-1 Mo -P22/F22 chrome moly material?
Is there a chart available in ASTM / other standards?
DV
Our company procedure says PWHT shall meet 730+-15 deg C )for P-5A (2.25Cr-1Mo
Base Metal (P-No.)
Temperature °F / °C
Minimum Hold Time1 (hr)
P-5A (2.25Cr-1Mo)
1350 ± 25°F / 730 ± 15°C
2
Our fabricator procured this material and in their PWHT procedure has Holding temperature...
Regarding Point 4: Tempering temperature is equivalent to lower critical temperature A1
For SA 335 P22 -lower critical temperature mentioned is 805 deg C .
But in the material certificate tempering is done at 740 deg C
So can PWHT temperature be above 740 deg C?
1. PWHT temp for P22 material -kept at 730+-15 deg C
- is this prevent prevent cracking of the weld
2.What is the optimum cooling rate after PWHT
3. Is post heat important for P22 welding
4."After welding, PWHT temperature is kept below the parent material tempering temperature by...
P22 Piping materials Tempering process carried out at typically 740degC. Whether PWHT holding temperature for P22 material can be above tempering temperature?
In the below thread there is a comment
The code committee, for various reasons, changed the factor against ultimate from 4 to 3.5 starting with the 1999 Addenda. Factors against yield, time dependent, and compressive did not change.
what are the current factors against yield,time dependent and...
For SA-106 Grade B pipe ,After 375 deg C the max allowable stress values are time dependant. Notes T1 & G10 ASME sec II Part D
NOTES — TIME-DEPENDENT PROPERTIES
T1 Allowable stresses for temperatures of 370°C and above are values obtained from time-dependent properties.
G10 Upon prolonged...
Hi
Derating of process piping
I want to know whether derating can be applied in the below scenario.
This is a modification of existing syngas line which is 15 years old. The current piping is designed to 550 deg C and pressure to 52 bar
But there is an alarm in the system at 285 deg C.
My...
In what circumstances design temperature of a piping system can be changed?
-In a operating plant ,the operating temperature of a particular pipe system (where alteration/Modification required) is max 300 deg C,above which there will be alarm/Trip.But the piping is designed to a higher...
