Weld bead callout on a print

[doohicky]

If I have a .06" callout for a weld on a print, how would that be measured?

I have an idea, but.......

Thanks for the help.

Mike

 

[metengr]

What kind of weld? Groove, fillet, etc.?

 

[doohicky]

It is a fillet weld I believe.

We have a thin wall pipe welded into a threaded fitting, and the callout is where the pipe is pressed into the fitting and then welded.

Mike

 

[metengr]

You can measure the face (or width) of the fillet weld and compare with the dimension called on the print. I have seen where fillet legs or the face dimension is specified.

 

[HgTX]

It's unconservative to measure the face, if the leg is really what the designer had in mind. If it's just a fillet weld symbol with a dimension, that's a leg measurement.

Or is the real question how to measure a weld that itty-bitty?

Hg

Eng-Tips guidelines: faq731-376

 

[diamondjim]

It is time to talk to the customer.
I would assume all he is trying to
do is assure that they have a leak
proof seal with the welding.

 

[doohicky]

HgTX, understand that the weld is to be a fillet, but instead of being concaved the weld is convexed(not sure if that matters or not), but I still have a problem with measuring the weld because of not knowing where the limits of the pre-welded parts were. In other words I do not think that I am able to measure this due to the lack of a definitive edge to measure from/to. Visually it appears to be closer to .125" and not the .060". Would the standard 3 decimal tolerances apply to this callout also? I believe that it should because there is no special note telling anything else.

diamondjim, we are the customer. Along with the weld callout there is also a requirement to be gas tight.


Thanks

Mike

 

[diamondjim]

Mike,
I probably am in error, but I have always
treated these as min requirements as to
welding specs. Machining tolerance requirements
do not apply to welding. Great question!

 

[doohicky]

Would you know of a standard that would spell this out for me?

Thanks

Mike

 

[BillPSU]

Ask your customer for the specification this is to be welded to. Use AWS D1.1 if nothing else. If this is a pressure vessel or some other certified structure you need to get the applicable standard.

 

[arto]

Sounds like you need a Fibre-Metal Template Fillet Gage set or a Palmgren Weld Gage

 

[doohicky]

Ok guys, I just did some looking on line and found out the the type of weld that is called out for on the print is a bevel weld(noted by the bevel symbol on the reference line). Pardon my ignorance to different weld specifications, I did not know this all existed.

BillPSU, would it be possible for you to give me a condensed version of this AWS D1.1?

Thanks

Mike

 

[HgTX]

AWS D1.1 is about 400 pages long and costs about $350. There is no condensed version. Purchasing of the welding codes appropriate to your applications should be part of your standard cost of doing business as much as the purchasing of your tools and raw materials.

If the weld is convex, you're okay in terms of effect on weld throat size as calculated from leg size, though perhaps the profile might be problematic in terms of stress concentrations. AWS D1.1 isn't appropriate for very thin material. You could try AWS D1.3, the sheet code, but it sounds like you might need a pressure vessel code.

If by "not knowing where the limits of the pre-welded parts were" you mean you might have unknown fitup gap, I don't know how to help you there. The weld size needs to be increased by the amount of gap, but you have no way of checking this once the part is already welded. Sounds like you really need to set up a proper welding program including quality control and inspection at all the appropriate stages. Hire a welding engineer, or at least bring in a temporary consultant. If failure of this weld might endanger human safety, your company is acting irresponsibly by welding without really knowing what you're doing.

If you're concerned about the 0.125" vs. 0.06", oversize welds are generally not disallowed for structural reasons. They can be problematic if the welding melted through the base metal, especially with double-sided fillet welds in which the long shape of the combined nugget can lead to cracking during cooling. They can give a false sense of security if the base metal strength is less than that of the oversized weld. At least in D1.1, for materials thicker than your application, fillet welds in lap joints are required to be 1/16" smaller than the material thickness so that the the unmelted edge of the material can still be seen, becaus a melted edge might disguise an undersized fillet weld.

All in all, if someone gave you a 1/8" weld instead of a 1/16" weld, that in itself isn't a problem, but if you have an unknown fitup gap that might be reducing that 1/8" weld to something less than 1/16", you could be in trouble.

Hire a welding engineer.

Hg


Eng-Tips guidelines: faq731-376

 

[doohicky]

I have inspected both the pipe and the fittings prior to welding, and the pipe is .4888" and that is going into a fitting with a diameter of .491+.003/-0". I do not believe that with this gap there would not be a cause for concern.

The vendor that is welding these parts has done so for may years, and me being new to QC(for this company)I needed to do inspections that dealt with the launch of a new product which utilized exixting componants, but made with different materials, so a layout was in order.

I just may contact the vendor to see if they can shed some light on this subject for me.

Thanks

Mike