ASME Sec IX QW 452.3 1

[david339933]

Hello,

If I am putting a 2" nozzle into a pressure vessel (10'ID), does the welder need to be qualified to weld down to 2"? In other words is QW 452.3 applicable? I have had conflicting answers and cannot find the answer anywhere in the code. The vessel is built to Sec VIII. If it is applicable it means that a welder would have to be tested on pipe, without backing, in order to put a nozzle in a vessel which has backing (GTSM).

Any references to clauses would be greatly appreciated. With conflicting answers I can't be sure without a clause to reference.

Thanks!

 

[Duwe6]

Your welder will have to test on 2"NPS or smaller to be qualified to weld a 2" Nozz. Sect IX makes the break between small-bore and big-bore pipe between 2"NPS and 3"NPS. Thus, to qualify to weld on small-bore, you have to be tested on small-bore. NOTE: small-bore stops at 1-inch OD / 3/4"NPS. To make buttwelds on smaller diameters than this, the welder has to qualify on that diameter or smaller.

Your welder will not need to qualify open-root if he will only be welding on backed, or back-gouged & double-welded items.

But if he has the skill, it is better to test using a small-bore open-root coupon. This gives small-bore + big-bore, and open-root + backed/double-welded qualifications. Much more cost effective, and makes scheduling which welder will be welding which joint or nozz much easier; they are qualified on everything.

 

[david339933]

So the nozzle to shell connection is the same as a pipe to pipe connection?

 

[qcrobert]

David,

Does the design call for CJP weld 2" nps? If so, then yes your welder has to be qualified by testing on a 1" OD pipe to 2-7/8" OD pipe thus qualifying the welder to weld pipe from 1" OD to unlimited OD pipe.

Refer to Sec IX QW-452-3 Groove-Weld Diameter Limits.

If your welder is already qualified to some or any size of pipe, he can weld the 2" pipe to the 10' ID pv if the weld called out is a fillet weld with a backweld fillet.

 

[weldtek]

It depends on whether the nozzle is set on vs. set through the vessel wall. If it's set through, QW452.3 doesn't apply.

 

[Duwe6]

Set-On tight, not full-penn = fillet weld, diameter limit is inapplicable.
Set-On, with a fitup gap and root = groove weld w/diameter limits for the welder
Set-Thru, fillets inside & out, shell not beveled = fillet, no diameter limit
Set-In, shell beveled full thickness, welded from the outside, or both sides = groove weld w/diameter limits.

 

[Fizza453]

Duwe6,

You said,

Set-In, shell beveled full thickness, welded from the outside, or both sides = groove weld w/diameter limits.

My opinion is, diamter limit does not apply in this case.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[weldtek]

Fizza453,

You are correct

 

[david339933]

Fizza453 and Weldtek.....can you explain why it does not apply? I am more confused now than when I started. There must be something in Section IX or Sec VIII that explains it.

 

[weldtek]

See interpretation IX-80-08

 

[metengr]

Basically, the difference is a set-on nozzle requires either a groove weld + fillet or a simple fillet weld. A set-in nozzle, there is no through-wall groove weld being applied to the nozzle wall, instead the groove weld is associated with the shell.

 

[Fizza453]

I like to add some words in continuation to metengr explanation, set on full penetration is a situation identical to that welder is making groove weld in pipe to pipe with backing.

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

 

[david339933]

Where can I find Interpretation IX-80-08. I have Section IX but not the interpretations.

 

[weldtek]

Linda Hall Library is one source I've used. There's others.
Basically the interpretation simply asks if a welder must be qualified on small diameter pipe for a saddle in type, [UW16.1(c)]for a hole diameter of < 2.875" Answer - No. Same question for saddle on [UW16.1(a)] - answer -yes.

 

[Duwe6]

Tha.ks, weldtek. As is usual in these fora, I learned something I needed to know.

 

[Fizza453]

I am copying here Interpretation IX-80-08.

Interpretation: IX-80-08
Subject: Section IX, Welder Performance Qualification
Date Issued: February 27, 1980
File Number: BC-79-341


Question (1): Is a welder required to take a "small diameter" pipe test to weld a "saddle in" [full penetration through shell as in Fig. UW-16.1, sketch (c) of Section VIII Division 1] when the diameter of the hole in the head or shell is less than 2-7/8 in. O.D.?


Reply (1): No, when the weld preparation is made in the head or the shell.

Question (2): Is a welder required to take a "small diameter" pipe test to weld a "saddle on" (full penetration through the nozzle as in Fig. UW-16.1, sketch (a) of Section VIII - Division 1) when the diameter of the nozzle is less than 2-7/8 in. O.D. and the weld prep is made on the nozzle?

Reply (2): Yes.

Question (3): What thickness of plate (test coupon) would a welder have to make his performance qualification test welds on to qualify for production welding of two 1 in. plates to be attached perpendicularly to each other by two partial penetration welds of 3/8 in. each?

Reply (3): The performance qualification test coupon would have to be a minimum of 3/16 in. thick

Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN