Welding Tips and Tricks

I had to do a 6 monthly 6G requal today. (2" sched 160)
Our Aussie qual standard "Pressure equipment - Welding and brazing qualification" AS3992 has a new 2015 edition which advises streamlining of welder qualification (not certification - that's a different standard) to be more in touch with international standards like ASME.

What this means for me today is that previously a 6 monthly requal coupon would require an x-ray. Today all that was required was a single macro. And what a beautiful macro it was if I may say so.

Anyone know what ASME requires for requal?

There is no requirement for an "inspected" coupon of any kind as far as ASME Sec IX goes. Just welding with the process within that 6 month period.

There are various ways companies address this. From simple statements to elaborate "Welder Continuity Logs"

Hope this helps.

Gerald Austin
Greeneville Tn

Edit: If your period of effectiveness has not lapsed(greater than 6 mos) then all you have to do is run a bead with the process. No NDE or destructive testing. If your qualications expire, then any test with that process will requalifo you for all previous tests. (if you are still testing under the same organization).

I've had to certify/recertify (yeah, certify, rather than qualify) for ASME twice.

Both times, it was 6g on 2" sch. 40 304SS.

First time was a four-bend, second time was x-ray.

ASME seems to allow flexibility between DT and NDE/NDT, so long as the result meets the standard. My currency is usually kept through x-ray, but, under certain circumstances can be done by pressurization, dye-pen, and even VT. It seems to be at the discretion of the inspector and the nature of the weld.

For example, nearly 20 feet of MIG was recently passed on a VT, and today I did a manway closure weld that will be inspected by hydro (actually pneumatic) pressure testing. Oddly, I only have to prove it at 30 psi for the inspector, but retest requires (and I'm going to test it to) 47 psi with full vacuum (for 62 psi effective pressure) with helium leak testing conducted at the same time.

I find it fascinating that the client's specifications are so much stricter than ASME's in this case.

Steve S

Otto Nobedder wrote: Oddly, I only have to prove it at 30 psi for the inspector, but retest requires (and I'm going to test it to) 47 psi with full vacuum (for 62 psi effective pressure) with helium leak testing conducted at the same time.

I find it fascinating that the client's specifications are so much stricter than ASME's in this case.

Steve S

Steve please explain this another way, if you have pressure you can't have a vacuum...

He converted the equivalent force on the tank from a vacuum to a pressure and then added in atmospheric pressure of 14.7 psig

LtBadd wrote:

Otto Nobedder wrote: Oddly, I only have to prove it at 30 psi for the inspector, but retest requires (and I'm going to test it to) 47 psi with full vacuum (for 62 psi effective pressure) with helium leak testing conducted at the same time.

I find it fascinating that the client's specifications are so much stricter than ASME's in this case.

Steve S

Steve please explain this another way, if you have pressure you can't have a vacuum...

These vessels are vacuum-jacketed... Like a huge Thermos Bottle, the product under pressure is in one vessel, surrounded by another vessel that is evacuated.

That means, with 47 psig on the inner vessel, and full vacuum surrounding it (as though it were in low-Earth orbit), the effective pressure is 62.7 psia.

Steve S

Otto Nobedder wrote: These vessels are vacuum-jacketed... Like a huge Thermos Bottle, the product under pressure is in one vessel, surrounded by another vessel that is evacuated.

That means, with 47 psig on the inner vessel, and full vacuum surrounding it (as though it were in low-Earth orbit), the effective pressure is 62.7 psia.

Steve S

Got it!
So you welded on both inner and outer walls? Are you able to post any photo's of your work?

Richard,

I'll probably be able to put a few up. These are pictures I can take without disclosing anything "proprietary", or disclosing who the client is. I still have to be cautious, as I'm not supposed to have a camera on the job, but I get a little leeway because of my position.

Steve S

Well I'm just glad I don't have to pay for xrays anymore just because nde of my work on site does not have my name on it.

Otto Nobedder wrote:Richard,

I'll probably be able to put a few up. These are pictures I can take without disclosing anything "proprietary", or disclosing who the client is. I still have to be cautious, as I'm not supposed to have a camera on the job, but I get a little leeway because of my position.

Steve S

That's ok, don't do anything to jeopardize your lively hood.