Slip-on flange welds 1

[jsymons]

I've suddenly had what I thought was a simple task made rather complicated.
The design code is ASME 31.3, the welding is to 15614-1.
To weld a slip-on flange to a pipe (in this case A106B, 8" SCH40) what are the governing material thicknesses?
Does my WPS/WPQR range have to include the flange thickness?
Never had a problem in the past using a butt weld PQR that just covers the pipe wall thickness.
Looking at 15614-1 I can see where they're coming from but... well it's a new one on me.

 

[XL83NL]

Its strange[tt][pre][/pre][/tt] to have 15614-1 on B31.3 piping. Nevertheless ...
Doesnt a buttwelded test coupon to 15614-1 also cover fillet welds, which are required for the welding the slip-on flange?

 

[racookpe1978]

To weld a slip-on flange to a pipe (in this case A106B, 8" SCH40) what are the governing material thicknesses?
Does my WPS/WPQR range have to include the flange thickness?

First, understand what the size of the fillet weld will be:
What will your two fillet leg distances be for that size pipe, that type of slip-on flange?
What is the wall thickness of the pipe?
What is the thickness of that size slip-on flange welding "collar" on the back of the flange?
(Remember, you have an outside fillet , and an inside fillet.)

Flange thickness has nothing to do with slip-on fillet weld leg lengths.

 

[jsymons]

XL83NL - A lot of the work we do now is to BS EN ISO for welding and NDT but to ASME construction code. There are whole libraries on ASME compliance with European regulations.
A butt weld does cover a fillet weld but the client is saying that the thickness of the flange must be qualified. It's almost like they are treating it as a thin wall branch to heavy plate.
RACOOPKE - I totally agree. The relevant thickness should be the design throat thickness which is generally proportionate to the pipe wall thickness.
The pipe is T=8.2mm and the flange thickness is about 40mm The hub thickness is about 12mm
Anyway, I'm arguing the common sense point. Was just hoping there was something in writing somewhere.
Oh and the testing house has recommended a PQR on a 65mm bar with a 5mm hole drilled through and welded to 30mm plate to cover fillets on anything t>5mm (I did well not to swear at that point)

 

[XL83NL]

Those complaince libraries are written on a (slightly) different topic I think, i.e. applying ASME codes (in full) to PED/EU, not on mixing codes.
When you start mixing it becomes tricky (or should I say dangerous?)

If EN 15614-1 qualifies you for welding a fillet, the client cant really argue with it I guess, unless they have some clause in a contract document that prohibitys this feature.
The challenge may now however be the material group A106-B is in acc. to ISO TR 15608 ...

 

[jsymons]

I'm not sure the use of BS EN ISO welding and NDT standards on ASME 31.1 (not 31.3 as stated before) piping is dangerous but care is required with grouping of ASTM materials, as you say. According to 15608 I think A106B is under group 11 according to its specification composition but all the actual values I've looked at make it Group 1.1 - I was told to consider it group 11

 

[racookpe1978]

A butt-weld (open root) WPS is usually very different than a backing plate WPS.

Most companies have a backed welded (covers fillets, structural bevel welds and backing plate pipe welds and often cover pass welds) and a separate one for open root welds.

 

[DekDee]

jsymons,
"Anyway, I'm arguing the common sense point. Was just hoping there was something in writing somewhere."

Don't try and equate the BS/EN codes/standards with common sense - not possible.

Based on EN ISO 15614-1 (Table 6) you have to take the thicknesses of both materials into account so you have to have coverage for the 40 mm flange thickness.
Not sure where your testing house got 65 mm from - greater than or equal to 30 mm gives you qualification range of greater than or equal to 5 mm.

Remember also, if fillet welding is the predominant production weld then you have to do a fillet weld procedure - you cannot use the butt weld procedure,
Cheers,
DD

 

[Duwe6]

or ignore the b.s. inherent in BS 15614-1 and actually build it i.a.w. ASME B31.3; the minimum leg length of the fillet is 1.4 X nominal pipe wall; fillet throat = pipe wall. 8NPS Sch40 = 0.322"
SO Flange weld is a "fillet". period. Just goes in a circle. Hire a new test lab/welding engr.

Under ASME B31.3, via Sect. II, a full-penn plate coupon suffices quite well for your PQR coupon. 4 bends, 2 tensiles, go home and have a beer.