Welding Tips and Tricks

Hello

While ago Jody did video about socket weld and talked a little bit of ASME B31. code.

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Well I ran into these welds at my work. Line is high purity line and that's why I'm wondering that are these welds clean enough for system

Funny thing here is that smaller diameter pipes/valves are welded with socket welds, but larger ones with full penetration using butt-welds. So what the heck!!

Is socket welds used on larger sizes at all? If not where goes the limit?

Here couple of photos. Pipe is 42.3x3.25 mm / 1 1/4 inch and what ever that thickness is

Markus,
I'm not sure what the upper limit is but I do have up to 4" ones throughout the plant. We have plenty of SS socket welds in our high pressure ultra high purity Hydrogen lines.

Len

Braehill wrote:Markus,
I'm not sure what the upper limit is but I do have up to 4" ones throughout the plant. We have plenty of SS socket welds in our high pressure ultra high purity Hydrogen lines.

Len

Is hydrogen in gas form or liquid?

Markus,
Actually both.

Len

Braehill wrote:Markus,
Actually both.

Len

Ok good to know thanks

Is it then that in high purity water systems for example full penetration is needed, because the risk of corrossion and not just because the inpurities?

Markus,
Not sure I'm the one to answer that, that's out of my realm.

Len

Markus,

The decision of socket-weld versus full-penetration butt-welds has nothing to do with purity of the product stream. It's an engineering decision between the efficiency of the weld versus the efficiency of the joint. The socket weld is preferred where pressure is more important than flow (note the sharp angles of socket-weld fittings), and the butt-weld is preferred when flow is more imprtant than pressure (note the long sweeps of butt-weld 90's).

The engineers will tell you about Reynolds numbers, which are measures of the efficiency of flow, but the short answer is, "flow" demands long corners, and pressure doesn't care.

Steve S

In a food grade situation the product stream would be affected by a socket weld fitting. The voids would trap particles that would be impossible to clean out.

Sorry for long answering time.

Socket welds will all be removed. Reason being the fear of corrosion, as the fluid inside is quite aggressive. Stainless is preferred quite prone to crevice corrosion, so it's good thing to replace socket welds to butt welded ones I think.

Good lesson for me once again

Interesting

In the latest welding journal, I saw these http://www.galgage.com/measuring_gap-a-let.html (maybe not same brand, but same function)
Do they actually work well?

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79jasper wrote:In the latest welding journal, I saw these http://www.galgage.com/measuring_gap-a-let.html (maybe not same brand, but same function)
Do they actually work well?

I suppose they would. I've never been on a job that would allow them, and the 90% reduction in "fit-up time" is a major exaggeration, in my opinion.

I've welded sockets all day where that li'l ring and it's use would stand in my way.

The short form is, it's a crush ring, and will stress the weld, regardless how ductile they claim it to be (yet still Autsinitic SS)...

Steve S