Understanding of ASME Code

[Lahane]

I have a impact tested weld procedure(GTAW+SMAW)qualified as per ASME SEC IX & ASME B 31.3 (P1G1 TO P1G2) the PQR coupon was of 12 mm thickness. the weld deposite by GTAW was 4 mm & by SMAW was 8 mm.So I guess base material (T) thickness qualified as per QW403.6 is min 12 mm to max 24 mm
Now I want to weld a set on (1.5" nozzle LTCS) 45 degree branch connection on header pipe(LTCS) of 6" OD.(offcourse impact test is involved)
The thickness of customized nozzle measures 7 mm & thickness of Header measures 10.97mm.As per drawing the throat thickness at acute side of nozzle requires min 15 mm & that of on obtuse side require 10 mm min.

My question is does my above PQR will suppot the above branch connection?
Does I have to apply a welder whose minimum Diameter qualification is 1.5" Dia or more?
A quick response to above query is highly appreciated.

 

[metengr]

My question is does my above PQR will suppot the above branch connection?

Yes, you can develop a WPS using this PQR.

Does I have to apply a welder whose minimum Diameter qualification is 1.5" Dia or more?

Since this is a fillet weld from your description and you qualified the WPS using a groove weld PQR, fillet welds are covered in all diameters (see Section IX, QW 451.4).

 

[weldtek]

lahane,
You didn't say which position the PQR was qualified in nor the position in which you intend to weld, but, for impact tested applications vertical up is an essential variable.

 

[CodeRef]

My $0.02....

If the weld preparation (bevel) is placed on the 1.5" OD nozzle, then yes, a small diameter qualification for the welder is required.

If the weld preparation (bevel) is placed on the 6.0" OD header, then no, a small diameter qualification for the welder is not required.

See questions 1 & 2 from interpretation IX-80-08 issued February 27, 1980

FAQ731-376

 

[GenB]

It looks that you are exceeding the T qualification procedure.
groove + fillet

 

[Lahane]

My PQR is qualified in 1G position & I intend to weld in 1G position only.
The joint described above is not a Fillet joint. It is a single bevel full penetration joint . The bevel is made on 1.5" nozzle & throat on acute side required is 15 mm.
Based on this 15mm weld deposite requirement can i use above PQR though the base material thickness is below 12 mm here.

 

[CodeRef]

I need to see the joint detail in a picture file.

From what I understand you are saying, a 1.5" OD 7mm nozzle, will be placed onto a 6" OD 10.97mm header with the bevel placed in the nozzle only and welded to a depth of 15 mm?? (this depth is twice the depth of the bevel in the nozzle) I do not understand... the term you used "throat" should be reserved for fillet welds.....Please clarify..

FAQ731-376

 

[GenB]

I believe you are okay welding the fiiting/nozzle.
your PQR allows double the coupon.
meet the x2 of the procedures as you are allowed up to double the GTAW and double the SMAW.
then small pipe does not apply here as you are doing groove on plate and not a pipe butt weld.
Check all your sect IX parameters PQR variables and also your welder has to be able to do the same.
genblr

 

[CodeRef]

GenB,

small pipe does not apply here as you are doing groove on plate and not a pipe butt weld.

not so.... small diameter qualification is not limited only to butt welds...it applies to groove welds...see the following interpretation....

Interpretation: IX-80-67
Subject: Section IX, Nozzle to Shell Connections
Date Issued: December 8, 1980
File: BC-80-675


Question: When nozzle or branch connections are attached to the wall or head of a pressure vessel, what are the basic criteria establishing procedure and performance qualification?

Reply: For groove weld procedure qualification, the base metal thickness range for all base metals being joined in addition to the deposited weld metal thickness range for each process used must be qualified in accordance with QW-451 (see QW-202.4). Also, see exemptions in QW-202 for fillet weld procedure qualifications.
For groove weld performance qualification, the deposited weld metal thickness range must be qualified per QW-452, and where the nozzle or attachment is welded to the vessel wall by welding through the thickness of the nozzle or attachment, a "set-on connection" performance qualification shall be made with the appropriate diameter pipe as required by QW-452.3. Where the nozzle or attachment is welded to the vessel wall with the weld preparation made on the vessel wall, a "set-in" connection, diameter is not a factor. See QW-303 for exemptions for fillet welds.



FAQ731-376

 

[Lahane]

Sorry currently I can not provide sketch but I will try to explain it again.
My bevel is on 1.5" Dia Nozzle,it's a set on 45 degree branch connection with full penetration single groove joint.
As the nozzle is at 45 degree,designer has set a min weld deposite of 15 mm at acute side & 10 mm at obtuse side. I have written minimum weld on each side as "throat" in above statement which leads to confusion.
My both the base metal(i.e header & nozzle) thickness are below 12 mm & min weld deposite required are 15mm & 10 mm.
So can my above PQR support my above groove joint as impact test is involved?

 

[CodeRef]

lahane,

Short answer ...Yes, with conditions....

I agree with most everyone else in this thread that your PQR is fine for the base metal(T) and weld deposit(w) ranges. I am having difficulty with the following:

1) Because this is a branch connection, a fillet weld is required to be added in accordance with B31.3 paragraph 328.5.4. I have listed paragraph 328.5.4 below for your convenience. Are you adding a fillet weld?

328.5.4 Welded Branch Connections
(d) Branch connections, including branch connection
fittings (see paras. 300.2 and 304.3.2), which abut the
outside of the run or which are inserted in an opening
in the run shall be attached by fully penetrated groove
welds. The welds shall be finished with cover fillet welds
having a throat dimension not less than tc. See
Fig. 328.5.4D sketches (1) and (2).

2) You stated ..... ”PQR is qualified in 1G position & I intend to weld in 1G position only” .....
Qualification in one position qualifies all positions for procedure qualification, however, how is it possible for you to intend to weld a piping branch connection in 1G? This sounds impossible to me. Even weldtek stated ..”vertical up as an essential variable”.... Welder Performance Qualification in 1G only would not be acceptable to me. Also, small diameter qualification requirements apply as stated in QW-452.3 of ASME Section IX if your design is a set-on type configuration with the bevel in the 1.5”OD nozzle.

3) Regarding impact testing and the GTAW and SMAW processes, read QW-406.3 referenced from the appropriate QW-250 tables. If impact testing is required, it appears to me that QW-406.3 governs. Here is QW-403.6 listed below for your convenience. Note that these indicate the minimum thickness qualified and not the maximum. Keep these parameters in mind.

QW-403.6 The minimum base metal thickness qualified
is the thickness of the test coupon Tor 5/8 in.(16 mm),
whichever is less. However, where T is less than 1/4 in.
(6 mm), the minimum thickness qualified is 1/2 T. This limitation
does not apply when a WPS is qualified with a PWHT
above the upper transformation temperature or when an
austenitic material is solution annealed after welding.

My $0.02.....I would like others to comment also...


FAQ731-376

 

[QC1971]

I would say the PQR will support a WPS that will permit welding of this joint.

The welder would need to qualify on a test coupon at least 7.5mm thick with an O.D. less than 2 7/8". This would allow the welder to deposit 15mm of weld and the welder would be qualified for materials down to 1" O.D.

 

[Lahane]

Fig. 328.5.4D sketches (1) and (2). are typically 90 degree branch connections.
The branch connection above is at 45 degree, will it requires a covering fillet weld as well?