Elbow wall thickness discrepancy

[gafoorkti]

Hi all,

We have received 4" sch 160(13.49mm thk) 90degree Long readius elbows from one of the renowned manufactuerer in the world and during UT thickness gauging, wall thickness at curvature/bent section is found less than the permitted variation (87.5% of WT= 11.9mm).
The raedings are found as follow: 10.5mm, 10.4mm, 10.2mm etc.

However, at the bevel ends wall thickness is found to be acceptable meeting/exceeding 13.49mm.

Can we accept these elbows? is there any code reference for acceptance of thinnng at bent section?

 

[BigInch]

Your design code will tell you if it is acceptable. Some codes have the minimum requirement you describe, other codes do not have any requirement for that, provided that their maximum turn geometry limitations are not exceeded.

Which code?

We will design everything from now on using only S.I. units ... except for the pipe diameter. Unk. British engineer

 

[Eddycurrentguy]

Taking UT readings at the crotch location can be affected by many factors such as type of transducer (dual vs single element), frequency, size, surface preparation, couplant saturation, operator experience, etc. You may want to re-examine these areas using an experienced technician to see if your data changes. Also, moving the probe in small increments may yield different results as well.

 

[gafoorkti]

Design code is ASME B31.3.

Is there any other code reference pertaining to wall thickness tolerance apart from ASME B 16.9.

 

[racookpe1978]

Are you in a high-erosion environment? High corrosion?