Detailing of Weld Prep

[marshell]

Hello,

I am working on a weldment of a square tube, where the 4 walls are welded together at the corners. I am calling out a Single V groove with a backing plate. I have modeled the tube in its finished condition with the 4 walls touching each other. I have also detailed the pieces out on separate pages. My question is... do I show the details of the pieces with the weld prep on them, or the full width? the specific weld callout and pre-qualified weld shows the corners with a 1/4 in gap when welding. I do not want the fabricator cutting the individual piece incorrectly to start based on the detail, but I also do not want a model with 1/4 in gaps showing in upper assemblies. What is the proper way of relaying the weld prep information on a drawing?

Thank you in advance.

Marshall

 

[flash3780]

I'd say that if you're detailing the piece-parts independently, go ahead and include the weld prep on the prints. The assumption there is that the guy machining the parts isn't the same guy welding them together.

If you're detailing the weldment, you'll likely be referencing a welding standard (AWS D1.1/D1.1M maybe?) that fully details the weld-prep. So, doing so on the face of the print would be double-dimensioning.

 

[MintJulep]

If from a process perspective it is advantageous to receive components with "pre-preped" and ready to weld edges then you need a drawing the fully and unambiguously defines what the parts are supposed to look like when they arrive.

If the models of those components doesn't work in the next higher assembly then you can't use them directly, so you'll need surrogate component models. Interesting drawing configuration challenge.

Alternately, you might consider a "weld bead" component within the assembly to make everything whole. That may work fine if all you need is a pretty picture. Probably not so well if you are also using the model for FEA and expect accurate results in the weld area.

 

[desertfox]

Hi marshell

Normally on drawings we only need show the weld symbol you require
see this link:-

http://www.welding.com/weld_symbols_welding_symbols.asp

However there no harm in detailing the preps for the welded joints particularly if one part is being machined prior to welding, its easier to have the prep machined on than the fabricator do it with a hand grinder.

Another link:-

http://www.twi.co.uk/content/jk65.html

desertfox