Impact Test Requirement for nozzle assembly as per UCS-66

[Ronak_Patel]

I have following configuration of nozzle assembly:-

1) Shell
Material: SA 516 Gr 70 (Curve B)
Thk :- 10 mm

2) Nozzle Neck
Material : SA 106 GrB ( Curve B)
Thk :- 6 inch ,14.27mm thk

3) RF Pad
Material: SA 516 Gr 70 (Curve B)
Thk :- 10 mm

4) Flange
Material : SA 105 (Curve A)
Size :- 150 class 6 Inch

Required MDMT for vessel is -20C . Temp reduction as per UCS-66b is not allowed as per customer spec.

I have Following query:-

1. Do I need to evaluate each of these components (Shell,nozzle,flange,RF Pad) for impact test requirement based on their MOC (curve) + THK combination according to UCS-66 (a) last line?

If I evaluate each of these component ,​

MDMT For shell :- -29 C (Impact testing not required)​

MDMT For Nozzle :- -18C (Impact testing required)​

MDMT For RF Pad:- -29C (Impact testing not required)​

MDMT For Flange:- -18C (Impact testing required)​

OR

Do I need evaluate to nozzle assembly as per UCS -66 (a)(1)(-a)(-4) ?

MDMT for Nozzle-shell Junction (Governing thk 10mm,Curve B) :- -29C​

MDMT for Nozzle-RF Pad Junction (Governing thk 10mm,Curve B) :- -29C​

MDMT for RF Pad-shell Junction (Governing thk 10mm,Curve B) :- -29C​

MDMT For nozzle assembly is -29C, which is lower than required and hence impact testing is not required . Does that mean my nozzle neck is not required to be impact tested?? ​

 

[r6155]

Do it as the client requires.

Regards

 

[Cobra17]

What about UG-20(f)?

 

[GD2]

OP,
You are correct by the rules of UCS -66 (a)(1)(-a)(-4. No impact test is required for the welded assembly. Note that Fig UCS-66 is used for both welded and non-welded constructions.
How about impact test for the weldment and HAZ? can you finish this task as well?

GDD
Canada

 

[Ronak_Patel]

@r6155 client has not ask for any specifics. As per code, is my nozzle neck exempted from impact test requirement??

@Cobra17 UG-20(f) exemption is not allowed.

@GD2 thank you for confirming. this seems bit counterintuitive though. Nozzle neck because of its own thickness is required to be impact tested but since my R.F pad and shell has lower thk than Nozzle neck, it is being exempted.