Ultrasonic Examination to AWS Code Requirements-Calibration and Application
Publication Date: 2012-Sep-15
The IP.com Prior Art Database
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"ULTP~ASONIC EX~AMINA~IO~ TO AWS CODE REQUIREMENTS/~. CALIBRATION AND APPLICATION"
TO BE PRESENTED TO THE HOUSTON CHAPTER OP THE AMERICAN SOCIETY FOR NONDESTRUCTIVE TESTING ON MARCH 16, 1978,
BY: J~ES E. TURNER, NDE LEVEL Ill PULLMAN KELLOGG - HOUSTON, TEXAS
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ULTRASONIC EXAMINATION TO AWS CODE REQUIREMENTS - CALIBRATION AND APPLICATION
This presentation is intended to clarify the operational mechanics of the AWS
Code requirements for Ultrasonic Testing of butt welds in welded structures.
At the present time there is a great deal of misapplication and misinterpretation
of instrument calibrations, testinq techniques an~ indication evaluation as
called out in AWS Dl.l~ The recent Level III Examinations indicated that a large
number of persons in the NDT Field do not understand AWS Dl.l Ultrasonic Require-
ment. Therefore, an explanation of the code procedures is in order. An explana-
tion will be given of instrument calibration~ ~esting procedures, and evaluation
of discontinuty indications. The code will be discussed in a step by step sequence as it is written. The handouts will be referenced from time to time and visual aids
will be used to make certain points of importance more easily understood.
AWS Dl.l Section 6, Part C "Ultrasonic Testing of Groove Welds" is contained in paragraphs 6.13 thru 6.22 of the Inspection Section of the AWS Code. Acceptance levels are included in Section 8 "New Buildings" & Section 9 "New Bridges".
Part C begins with Paragraph 6.13 which details the general application of ultra- sonic testing to the AWS Code (See - handout Page 77).
Paragraph 6.14 explains the extent of testing, both complete testing and spot testing (See - Handout Page 77).
Paragraph 6.15 Describes the Ultrasonic Testing Equipment Limitation that must be followed including instrument type, transducer types, sizes and frequencies.
18.104.22.168 Describes the Transducer Resolution Verification Techniques using the Transducer Resolution Test Block. (Show slides #1 & 2). (See handout Page 78 & 79). Paragraph 6.16 states that the IIW test block is the primary calibration standard for the AWS Code. However other smaller blocks may be acceptable. Before any further discussion of the code is attempted; Applications of Test Blocks as covered in Paragraph 6.21 must be discussed. (See handout, pages 79, 80, 82, 83 & 84.
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Paragraph 6.21 covers calibration of the Ultrasonic Unit with the IIW or other approved calibration blocks. The IIW Block and DSC Block Calibration will be discussed fully.
Longitudinal Mode - Straight beam calibration is covered in 621.I
Due to the simplicity of the calibration it will not be discussed.
Pages 82 & 83).
Shear Wave Mode (Transverse) calibration is covered in 621.2 and will fully. (See handout Pages 83 & 84).
To locate the transducer sound entry point:
ULTP, ASON..IC EXAMINATION & ETC. (Cont'd)
I. Set the transducer as indicated in slide #3 for IIW & Slide #4 for DSC.
2. Move the transducer until the signal from the radius is maximized.
3. The point on the transducer wedge which is in line with calibration block line is the point of sound entry. Slide #5 (See slide 4 again).
Determine the Transducer Sound Path Angle by th...