Showing weld beads on a drawing 1

[marshell]

In AWS 2.4, they show the weld cross section, and they will show the "symbol" next to it. The symbol picure will show no weld representation except for the leader and symbol. My question is... Is it acceptable to show the weld bead on the drawing with the weld symbol pointing at it. I am being told that since the AWS specification does not show the weld beads in the call-outs, they should not show on the drawing. With the current cadd technology, it is so simple to put on there, and since I show them in the model, it causes more work to not have them on the drawing. I am looking for somewhere that states they "shall", "shall not" or "it doesn't matter" if they are shown.

Thanks in advance

 

[gtaw]

If the additional information is useful to the welder or inspector and if it is worth the extra effort I see no reason you cannot add the weld bead to the drawing. However, most drawings are busy enough without adding more lines to the confusion. The purpose of using a welding symbol is to reduce the clutter that appears on the drawing. The welding and NDE symbols are a shorthand method of providing information about the location, size, and type of weld as well as the examination requirements. It sounds as if you are reverting back to the "dark ages" when there wasn't a standard way of presenting the information.

I guess the old method of an arrow pointing to a crosshatched fillet weld with the notation "weld here" isn't dead after all.

Best regards - Al

 

[MikeHalloran]

I have occasionally designed assemblies where the weld bead had to clear some adjacent or passing part.
In that case, I generally include a section that makes the clearances abundantly clear, and include a weld bead to scale.
Otherwise, there is no particular reason to show the bead when a symbol is sufficient.



Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

I have also once attempted to get an asymmetrical weld done 'the wrong way', and included a section and a perspective for that purpose. The additonal pictorial information was ignored, and the weld was made 'the right way'.
... causing us some extra machining that I was trying to avoid.



Mike Halloran
Pembroke Pines, FL, USA

 

[tbuelna]

marshell,

With most current CAD systems, it is very quick and easy to add graphical representation of the welds to a solid model and drawing. I'm a design engineer myself, and I always try to make my drawings as detailed and explicit as possible, so that there is nothing about the component shown on the drawing that must be interpreted by the machinist/fabricator/inspector.

With modern CAD systems it only takes a few minutes to add another view/section/detail providing a specific description of any aspect of the design. The only reason for not doing so is simple laziness on the part of the designer/draftsman.

Regards,
Terry

 

[racookpe1978]

Simple butt weld? Usually, there is no "extra information value" added by drafting in the actual weld (final) weld geometry.

Fillet welds? In a tight or complex assembly - yes, DO add the fillets, particularly when extra machining is needed after the welding or bolt lines come anywhere near the weld. Counterbores may need to to be made into the "curve" of the fillet, or the bolts or washers will not lay flat across the weld "curve" for example. Or, you find after drafting the "ideal" fillet that there isn't any metal present to weld: the intersecting steel plates need to be weld-prepped into a single-V or the joint redesigned so there is actually metal present to weld into.

Or, a valid, useful (strong) fillet weld can't be produced into a "canyon" or notch where several pieces of steel intersect, particularly at odd angles or inside acute angles. Changing the order of assembly and welding, or changing the joint design and weld prep's may greatly reduce the cost of fabrication and the quality of the joint.

But, if you have plenty of room and no potential interferences and easy access? Don't bother if you are sure there will be no problems and you are sure that the joint can be made up cheaply and accurately..

 

[MintJulep]

With a few exceptions, when used correctly AWS symbols are precise and unambiguous.

When associated with a correctly defined WPS those few exceptions will almost certainly be clarified.

So there should be no need to show the weld bead on a drawing for the purpose of creating the weld.

There doesn't seem to be an prohibition against adding the bead to a model or drawing, so if it clarifies the design intent I don't see why not.

Cases where it might be helpful include: Joints where the weld is not the full length, and the start and stop location need to be controlled; intermittent welds where the spacing needs to be controlled; cases where the bead must be machined to a specific dimension as a finishing step.

 

[racookpe1978]

Also: weight control - rockets or aero where ounces are important that is - may create a need.

Actual "weld metal" can't be included in center-of-gravity or total weight calc's unless the extra weld volume is included. Also, if the "parts" are modeled in 3D CAD with a weld prep, then unless the weld is also modeled, the final weight and CG ill be "off" by the absense of replacement metal.

 

[tbuelna]

Simple butt weld? Usually, there is no "extra information value" added by drafting in the actual weld (final) weld geometry.

I just worked on a program where most of the welds were butt-type welds, but were anything but "simple". The parts being welded were large diameter, very thin wall, fracture critical Inconel ducts for LH2/LOx propellants on a manned launch vehicle. Butt welds were generally required since they could be more thoroughly inspected than any other type of weld joint. While the actual weld symbol itself used on the face of the drawing was conventional, there were also a large number of flag notes attached to each weld symbol. The flag notes referred to numerous manufacturing process and inspection documents, as well as weld analysis requirements. There were also extensive tables on each drawing that described the welding sequence and NDI requirements for each weld at each step in the process.

As far as the final geometry of these butt weld was concerned, the profile of the weld on the duct inner flow surface was very critical, and was controlled by a manufacturing spec rather than the weld symbol itself.

 

[StrPE]

Stop wasting time showing weld beads.

 

[paddingtongreen]

The danger, from my point of view, is that the nearside/farside indicators will, over time, be ommitted as unnecessary if the bead is shown in anything but blown up sections, where their absence might cause questions.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[Ron]

I don't see the need. Present system is sufficient and unambiguous.