UT(AWS vs ASME)

Date 05-17-2007 18:36

Dear all,

When I am going to use AWS D1.1 standard for Ultrasonic Testing, usually my reference standard is the 1.5 diameter hole/15mm depth from IIW block @ 52db 80%FSH, But when I am also going to construct DAC Curve based on the ASME Section V&VIII,using ASME reference block(thickness=19mm & 2mm diameter hole @ 5mm depth) @ 42db 80%FSH for 1st reference Peak and so forth.
My Question is why that AWSD1.1 has greater reference dB since it is only use for structural compare to ASMEVIII that it is being use in more complicated products?

By 803056

Date 05-17-2007 21:02

Different code, different people writing the code, different opinions, and different loading conditions.

Al

By dmilesdot (**)

Date 05-22-2007 14:16

Here is something to think about, why do we use holes to calibrate by? They dont give a realistic representation of what we are looking for in the field. A curved surface scatters more sound energy than it send back to the transducer. I would ask that in your situation are you using the same transducer to get the calibration results in both situations?
Dave

By rodrod

Date 05-24-2007 12:34 Edited 05-24-2007 12:36

As per Code & Standard, I am using the same transducer that has been use in calibration and testing of materials. In testing of curved surface I was using the curved surface factor but since the reflection of sound is not the same refletion in flat surface since their is already attenuation & Scaterring of soundwaves. In which the height of the peak in curved surface will be lesser compare to flat surface.

The question that always in my mind is that, Why that AWS D1.1 Standard has greater Reference decibel compare to ASME Standard.

By hogan

Date 05-24-2007 14:39

the different approaches to measuring attenuation could be a factor