UW-52 Clarification

[BGinBC]

Hi there,

After doing some searching on this site I couldn't really find the answer i was looking for. Based on some of the threads that I have read, my question must be pretty basic.

The welds in question are type 3.
Regarding Extent of spot, Section VIII-1 calls for a minimum of one spot per 50ft of weld. UW-52(c) specifies 6" per spot.

I have a total of 83ft of weld, so I need 2 6" spot welds. Is this correct? It just doesn't seem like very much of a sample.

Thanks!

 

[gr2vessels]

2x6" is correct. It will be sufficient to prove once again the welding spec and qualification, in addition to the extra material thickness you have included in your design / fabrication.

 

[brandonb73]

Am I reading table UW-12 wrong? The way I interpret it, you don't get any extra credit for RT of a Type 3 joint. You just have to use a .60 join efficiency.

 

[vesselfab]

YES SIR

That's what it says. single sided with no provisions of a good root pass with reinforcement to meet UW-35.

 

[brandonb73]

So.....I'm confused about the original question, if UW-52(c)doesn't apply to Type 3 joints.

 

[vesselfab]

you are mixing paragraphs.

uw-52 is what and how much gets radiographed

uw-12 is joint efficiencies

TRUE his does not get anything out of RT of the welds but maybe his customer is requiring spot rt.

If it is truley a type 3 weld, i don't know how he will ever get clear radiographs unless he actually puts in a good root pass. then it's a type 1 weld and he could get better joint efficiency

 

[BGinBC]

Basically, I am but welding 10" sch40 pipe, to make up a Section VIII-1 vessel. Our calculations were done to using type 3 joints and the design calls for spot x-ray.

 

[PVinspector]

If the design calls for spot x-ray per ASME VIII-1, then you are correct with 6" per 50', two shots in your case. Keep in mind this is only valid if the shots capture every welder. It does not seem like much, but if one of them fails you will get the opportunity to see more!