Acceptance Criteria for Single Tungsten lnclusion API1104

Date 08-06-2019 13:23

Checkout - https://app.aws.org/forum/forum_search.pl?words=tungsten+inclusion&user=&board=0&field=body&min=&max=&order=desc

IN ASME B 31.3 Table No. 341.3.2 criteria are given

Slag inclusion, tungsten inclusion, or elongated indication
Individual length ≤ T w /3
Individual width ≤ 2.5 mm (3⁄32 in.) and ≤ T w /3
Cumulative length ≤ T w in any 12T w weld length

Slag inclusion, tungsten inclusion, or elongated indication
Individual length ≤ 2T w
Individual width ≤ 3 mm (1⁄8 in.) and ≤ T w /2
Cumulative length ≤ 4T w in any 150 mm (6 in.) weld length

By 803056

Date 08-07-2019 15:18

Since your referenced API 1104, they don't specifically address tungsten inclusions. However, one could approach the problem by treating the tungsten inclusion as you would porosity. The justification being that tungsten inclusions are typically rounded, unlike slag inclusions that often have sharp end conditions. Basing the acceptance on porosity, the criteria for a single pore hole is as follows:

9.3.9.2 Individual or scattered porosity (P) shall be considered
a defect should any of the following conditions exist:
a. The size of an individual pore exceeds 1/8 in. (3 mm).
b. The size of an individual pore exceeds 25% of the thinner
of the nominal wall thicknesses joined.
c. The distribution of scattered porosity

I was going to say, "check the pipe wall with a flashlight, if the light doesn't shine through, you're good to go."

Hope that helps - Al

By Shane Feder (****)

Date 08-11-2019 13:26

Al,
With all due respect my friend I have to strongly disagree.
I spent 4 yrs as a radiographer and after viewing a multitude of tungsten inclusions I can honestly say none of them were ever "rounded".
The tungsten is ground to a sharp point and when it is broken off due to poor welding technique it will show up on the graph as a very sharp pointed indication (less sharp if it has been in use for a while but no where near rounded).
I think the API committee may have failed to include TI's because the use of GTAW on a pipeline would not be considered "normal practice".
Cheers,
Shane

By 803056

Date 08-11-2019 13:36

Shane, I will concede to your experience. I do have to ask; did you see a prevalence of tungsten inclusions that were pointed or rounded?

I can't recollect seeing one that didn't have rounded ends, i.e., they may have been oblong rather than spherical. Then again, my experience with RT is not extensive.

Al

By Jim Hughes (***)

Date 08-11-2019 12:05

Jahead1,
I think the poster is looking for advise under API 1104 not ASME B31.3.

By Jim Hughes (***)

Date 08-11-2019 12:02

Abhi,
I would recommend that you obtain a copy of API 1104 21st edition to review. In my experience, Tungsten would be graded as a rounded indication.
9.3.9.2 a) Anything larger than 1/8" is rejectable. So 4mm=0.157, which is rejectable.
API 1104 9.4.1 b. (b) Relevant indications are those caused by imperfections. Linear indications are those in which the length is more
than three times the width. Rounded indications are those in which the length is three times the width or less.Rounded indications shall be evaluated according to the criteria of 9.3.9.2 and 9.3.9.3, as applicable. For evaluation
purposes, the maximum dimension of a rounded indication shall be considered its size.