ASME IX weld qualification scaling

[hsemus]

Hi could you please let me know where can i find information in the ASME IX for the scaling thickness of the pipe for qualifying butt welding.

i have two different size pipes with two different thickness. So can I use the minimum thickness pipe to qualify for both butt welding or do I have to qualified separately.

 

[DonRoss]

I suggest qualifying 1/2" SCH 160 pipe [.188" Wall] or if available XX Hvy [.294" Wall] in 6G position.
This qualifies Diameters from Ø 0.84" and Larger, provided the material thickness of the larger pipe is equal to the tickness range qualified of 2T. For example: SCH 160 is .188" x 2 = .375" thickness qualified or XX Hvy is .294" x 2 = .588" thickness qualified.

For direction, refer to ASME Section 9:
- QW-450/QW-451.1
- QW-452.1(a)
- QW-452.1(b)
- QW-452.3
- QW-461.9

 

[DekDee]

Don,
The only problem with using 1/2" is you require multiple coupons.
This route is only usually used if qualification is required for welding 1/2" in production.
A 2" coupon will give almost the same diameter range, is easier for the welder and only requires 1 coupon.
A 1/2" coupon qualifies for size welded to unlimited.
A 2" coupon qualifies for 1" OD (25.4 mm)to unlimited. A 3/4" pipe has an OD of 26.7 mm so basically it is 3/4" (NB) to unlimited.
Regards,
DD

 

[DonRoss]

Hi DekDee,

I appreciate the input, it's nice to learn about how others handle Procedure and performance qualifications.

I'm not entirely sure if a Ø 1/2" coupon would require multiple coupons...
The lab we deal with is able to extract two root and two face bends from a single Ø 1/2" SCH 160 coupon to qualify 6G position according to QW-463.2(d).

What I typically do, is qualify the procedure (depending on the application) using a 3/8" plate [1/16" to 3/4" thk], single sided butt-weld in a 1G or 2G position. Then I qualify the welder using a 1/2" SCH 160 pipe in 6G position to cover the techniques and processes we require.

Since we are required to weld small bore piping, using 1/2" SCH 160 pipe works out best for us as you explained.

Thanks,

Don

 

[DekDee]

Don,
My apologies.
Based in the Southern Hemisphere for some reason nobody uses the mechanical option for welder qualification.
It is always volumetric (predominantly RT with UT coming into play now)
Regards,
DD