ISO 10893-10:2011 pdf free download – Non-destructive testing of steel tubes一 Part 10: Automated full peripheral ultrasonic testing of seamless and welded (except submerged arc-welded) steel tubes for the detection of longitudinal and/or transverse imperfections.
6.3.2.4 The tolerance on notch depth shall be ±15 % of reference notch depth or ±0,05 mm, whichever is the greater, with the exception that when the notch depth is less than 0,3 mm, the tolerance shall be ±0,03 mm.
6.3.3 Notch length
Unless otherwise specified by the product standard or agreed on by the purchaser and manufacturer, the length of the reference notch(es) shall be greater than the width of the single transducer or single virtual transducer, with the following limitation:
maximum of 25 mm for cold-drawn, cold pilgered or machined tubes;
maximum of 50 mm for all other conditions.
6.3.4 Verification of the reference standards
The reference notch dimensions and shape shall be verified by a suitable technique.
7 Equipment calibration and checking
7.1 General
At the start of each inspection cycle, the equipment, independently of the applied type of waves, shall be calibrated to produce consistently clearly identifiable signals from the reference notches used. These signals shall be used to activate the respective trigger/alarm.
7.2 Adjustment of triggerlalarm level
7.2.1 Where a single trigger/alarm level is used, the probes shall be adjusted such that the signals from the internal and external reference notches are equal, as far as possible, and the full signal amplitude of the lesser of the two signals shall be used to set the trigger/alarm level of the equipment.
7.2.2 Where separate trigger/alarm levels are used for internal and external reference notches, the full signal amplitude from each notch shall be used to set the relevant trigger/alarm level of the equipment. The position and width of the gates shall be adjusted in such a way that the entire wall thickness of the tube is tested.
7.2.3 When only the external notch is used, the full signal amplitude from the external notch occurring immediately after the internal gated time period shall be used as the internal notch signal amplitude.
8 Acceptance
8.1 Any tube producing signals lower than the trigger/alarm level shall be deemed to have passed this test.
8.2 Any tube producing signals equal to or greater than the trigger/alarm level shall be designated as suspect or, at the discretion of the manufacturer, may be retested. If, after two consecutive retests, all signals are lower than the trigger/alarm level, the tube shall be deemed to have passed this test; otherwise, the tube shall be designated as suspect.
8.3 For suspect tubes, one or more of the following actions shall be taken, subject to the requirements of the product standard:
a) the suspect area shall be dressed or explored by a suitable method. After checking that the remaining thickness is within tolerance, the tube shall be retested as previously specified. If no signals are obtained equal to or greater than trigger/alarm level, the tube shall be deemed to have passed this test.
The suspect area may be retested by other non-destructive techniques and test methods, by agreement between the purchaser and manufacturer to agreed acceptance levels;
b) the suspect area shall be cropped off;
c) the tube shall be deemed not to have passed this test.