welder certification size restriction

Date 01-16-2010 23:38

Hi when you are testing out for an ASME coding what is the restriction on miniimum size certified. For example if you test on on 6 inch pipe its says on the coding that the minimum size pipe you are certified for is 2.5 inch pipe and that means you are not certified to weld smaller pipe right ?? And if so what size of pipe do you have to test on to be certified for 1 inch pipe etc.

By Duke

Date 01-17-2010 03:03

For groove welds, looks like 2 7/8" OD test lets you weld 1"; anything less, you test that size or smaller.
if I am reading Sect IX QW-452.3 correctly.
If not, someone enlighten me, I have a guy welding natural gas pipe in my building.

By north_fl_cwi (*)

Date 01-25-2010 21:09

Take the "monster coupon" and no need (just about) to take anything else. 2-3/4"od x 5/8" wall. That will get you 1" and larger on pipe size, unlimited thickness, and all fillet welds.

By ssbn727 (*****)

Date 01-25-2010 22:25 Edited 01-25-2010 22:59

Not if one is going to be welding schedule 10, 1" or less diameter pipe... I know because I had to test a few times with a schedule 10, 316L, 1/2", .062 wall pipe (even though the the wall thickness for that diameter pipe is .083") to be qualified to schedule 10. ;)

Btw, here's a good link to pipe schedule terminology if anyone is interested:

http://www.engineeringtoolbox.com/pipe-schedules-d_557.html

Respectfully,
Henry

By Duke

Date 01-26-2010 02:26

you learn something every day... i always thought double X was sch 160

By north_fl_cwi (*)

Date 01-26-2010 13:08

ASME IX
QW-452.1
Thickness of weld metal in coupon - Thickness of weld metal qualified
All - 2t (2 times test coupon thickness)
1/2" and over with a minimum of 3 layers - Maximum to be welded

QW-452.3
Outside Diameter of Test Coupon - Min Qualified - Max Qualified
Less than 1" - size welded - Unlimited
1" to 2-7/8" - 1" min - Unlimited
Over 2-7/8" - 2-7/8" min - Unlimited

With that said, if you had run a GTAW root on the monster coupon (2-3/4" x 5/8"), you would have been qualified to weld 1", sch 10, ss pipe if you had run the GTAW process all the way out. But without knowing what process you qualified on, and all the particulars of what you were welding on, it's hard to tell. And then on top of that, every company has the right to test you in any process they want. But if you are going to weld smaller than 1" pipe, then yes, another test would be required.