Dissimilar thickness groove WPS, or something else? 1

[timsch]

I've attached a snapshot of an assembly drawing that shows a thermocouple (item 9) which passes through a bored hole in a piece of round bar (item 6). The weld callout specifies a 1/16" chamfer to be filled and then capped with a 1/8" fillet. The thermocouple sheathing is around 0.050" thick, and the bar is usually around 3" thick axially and the same or more diametrically. The drawing shows only one thermocouple, but the assembly usually has multiple thermocouples in a radial pattern around the axis.

This is part of a U-stamped assembly, so ASME SEC.VIII, DIV.1 is typically used. When looking at section IX QW-202.4, I'm left wondering whether it applies to differences of thickness as extreme as this. With only a 1/16 chamfer in the bar, is it even considered a groove weld?

 

[DVWE]

Just my opinion, but I don't think that qualifies as a groove weld, even though a groove weld is implied within the welding symbol.

To me, that is nothing more than a little bit of root preparation to ensure better root penetration of a fillet weld. I believe QW-202.2(c) applies. Just make sure a properly qualified WPS is used in production.

Does the weld see pressure?

The devil is in the details; she also wears prada.

 

[timsch]

Thanks for the replay DVWE. The weld does see pressure. We do have an approved WPS, but right now a 3rd party inspector for a PED job is looking at it and he is claiming that it is a groove weld and in order for him to approve the existing WPS for PED, a coupon with representative dissimilar thickness will need to be produced. I am trying to persuade him otherwise. A groove joint with thicknesses this dissimilar is likely not even considered feasible. Fillet weld joint, sure....

 

[DVWE]

Yeah, good luck with that one (3rd party)....been there, done that.

Might be a long shot, but you could easily revise that drawing and remove the groove weld symbol. Simply put in the tail of the welding symbol something to the extent of, "Chamfer Item 6 at 1/16" prior to welding".

The groove weld is removed and he/she has no argument at that point. At least in my opinion...

Your other option is to combine a couple of PQRs or WPSs to meet your required base metal thicknesses from Table QW-451.1

You need something qualified for less than 1/16" and what sounds to me like up to 8".

The devil is in the details; she also wears prada.

 

[david339933]

How is this connection designed? UW-16(e)? 1/16" groove sends warning flags. UW-16 allows NPS 6 or less to be attached from one side only, but groove is mandatory unless the nozzle neck extends flush to the inside of the vessel. The attachment weld tw shall be no less than tn nor less than 1/4".

 

[timsch]

The nozzle neck, in this case the thermocouple, extends fully through the bore in the bar and into the vessel. Fortunately, the AI came around to agreeing with me. I proposed revising the weld symbol, but he said that would not be necessary.

Thanks for the feedback.

Tim