American Welding Society Forum
How many coupons needed for welders qualification of welder from 1/2" XS (21.3 OD thk 3.73mm) GTAW according to ASME Sec. IX
i calculated 3 pcs are enough to achieve 150mm weld length . but it was requested from me to do in 4 pcs. because it is necessary to calculate according to inside diameter of 1/2"
can anyone tell something about this ? why inside diameter of pipe should be considered as weld length ?
of course 4th one will not make lots of problems but i want to understand the issue. i checked the section IX and i found only 150mm weld length is required to qualify a welder. this can be done in multiple coupons, but while calculating weld length of 1/2" pipe should i consider inside diameter or outside diameter ?
using your numbers 13.84mm ID 43.48 total I.D. weld surface length. * 3 = 130.44mm total length. *4 = 173.92mm total length. In order to weld the equivalent plate >= minimum of 150mm face and root, you will need 4 if I've done the math right. It's my understanding that the root area/ID has to meet or exceed the minimum required weld length as well as the face/OD.
thank you for your reply. According to ID your calculation are correct without any question mark. I agree also with your understanding about the root are / ID has to meet or exceed the minimum weld length. what i tried to say was, i could not find this in sec. IX
if a welder is qualified from 2" XXS pipe (11.07mm thickness) welder has to weld 2 joints?
furthermore QW452.3 groove weld diameter limits are given in outside pipe diameter.
ID= 60.3mm - (2 x 11.07mm) =38.16mm
ID x PI (3.14) = 38.16 x 3.14 = 119.8224mm
it is not possible to qualify a welder in single pipe, if we consider 150mm length from root of the pipe.
The weld length is based on the circumference of the pipe (QW 304.1 (b)) and I am pretty sure that the circumference referenced is meaning the OD of the pipe, not the ID.
A single 2" pipe (60.3 mm OD) has been the standard size used for years for welder qualification, this gives approx 180 mm weld length.
Hope that helps,
Shane is correct. I believe it is calculated from the OD regardless of where your process falls in that pipe (Section IX does not address that, and therefore cannot be limited based upon the code).
Section IX to my knowledge also does not address directly the OD/ID issue, but it implies it when you review the diameter limitations for a 6" qualification.
If memory serves, it limits it to 2 3/8" diameter which is the OD of a two inch pipe. Thicker walls come off the ID. Therefore a 6" qual will qualify you to 2" pipe.
This is the intent of the Section IX limitation. Therefore the implication that it is OD governed.
I think you will find that it is 2 7/8" (73 mm) OD that is the limit.
A 6" test coupon will only allow you to weld pipe greater than 2 7/8" (73 mm) OD.
To weld 2" and 2 1/2" pipe you would generally use a 2" pipe test coupon.
You are right. I stand corrected. I don't have a copy of Section IX in front of me so I have to rely on my erring memory.
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