Checkline DFX-7 - Manual (Page 59)

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CHAPTER SEVEN
AWS – WELD INSPECTION
7.1 Introduction to AWS
AWS provides a toolkit for evaluating defects according to the American Welding
Society D1.1 welding code. The code offers inspectors a method to classify
discontinuities by calculating and Indication Rating (IR) using ultrasonics. This toolkit
can be used in conjunction with TRIG mode, outlined in the previous chapter, to
simultaneously display the sound path (SP), surface distance (SD), and depth (D).
The following sections provide an outline for using the AWS feature.
7.2 Additional Comments
Since the DFX-7 is a gain controlled instrument, the following formula applies:
A – B – C = D
Where:
A = Discontinuity Indication Rating (DI)
B = Reference Indication Level (IL)
C = Attenuation Factor (AF); or 2(SP – 1)
SP = sound path in inches (2dB loss per inch of material thickness)
D = Indication Rating (IR)
Note: all values are in dB.
Calibration Standards & Calibration:
In order to use the AWS feature, the operator must have calibration standards made
with the same size reflector at different distances within the testing range. The
standards should also be made of the same material type as the material to be
inspected.
AWS D1.1 Standard:
There are specific transducers that are required by the D1.1 standard. The
frequency specified by the standard is 2-2.5MHz. The user should refer to the
standard for further information.
7.3 Setup AWS
This section provides a step by step procedure to enable and setup the AWS feature.
Note: A two point calibration should be done prior to proceeding. Refer to Chapter
Five for the calibration procedures. The TRIG mode will also be used for weld