ISO 10893-8:2011 pdf free download – Non-destructive testing of steel tubes – Part 8: Automated ultrasonic testing of seamless and welded steel tubes for the detection of laminar imperfections.
6.3 Verification of reference standards
The reference standard dimensions and shape shall be verified by a suitable technique.
7 Equipment calibration and checking
7.1 At the start of each test cycle, the equipment shall be calibrated statically either without a reference standard in accordance with 7.1 a) or using a reference standard in accordance with 7.1 b).
a) Calibration without a reference standard: with the probe assembly positioned on the tube under test, the full amplitude of the first back wall echo minus 6 dB shall be used to activate their respective trigger/alarm level of the equipment.
The test sensitivity may be established with distance amplitude correction (DAC) curves as supplied by the transducer manufacturer or DAC curves as prepared by the tube manufacturer using, in both cases, the 6 mm flat-bottomed hole curve.
The manufacturer shall demonstrate that at the set sensitivity, the equipment detects under static conditions the reference standard as given in 6.1.2 and Figure 1. If this is not the case, the necessary adjustment in sensitivity shall be made prior to the testing of production tubes.
b) Calibration using a reference standard: under static conditions, with the transducer or each transducer of a probe assembly centrally located over the reference standard, the full signal amplitude of the signal obtained from the reference standard shall be used to activate their respective trigger/alarm level of the equipment.
7.2 During production testing, the relative rotational and/or translational speeds and pulse repetition frequency shall be chosen to provide full surface coverage of the zone of the tube under test.
7.3 The calibration of the equipment shall be checked at regular intervals during the production testing of tubes of the same nominal diameter, thickness and grade.
The frequency of checking the calibration shall be at least every 4 h, but also whenever there is an equipment operator team changeover and at the start and end of the production run.
8.2.3 Test in accordance with 5.4
The manufacturer may either reject the tube or crop off the suspect area. In the latter case, the manufacturer
shall ensure that all the suspect area has been removed and shall submit the end zone of the remaining
length to a repeat test as specified in 5.4.
9 Test report
When specified, the manufacturer shall submit to the purchaser a test report including at least the following information:
a) reference to this part of ISO 10893, i.e. ISO 10893-8;
b) statement of conformity;
c) any deviation, by agreement or otherwise, from the procedures specified;
d) product designation by steel grade and size;
e) type and details of test technique(s);
f) equipment calibration method used;
g) description of the reference standard acceptance level;
h) date of test;
i) operator identification.