BS EN 16090 pdf free download
BS EN 16090-2019 pdf free download.Copper and copper alloys — Estimation of average grain size by ultrasound.
4.2 Condition of products to be tested Products shall be sufficiently clean to permit satisfactory test operation and adequate coupling. Products shall be free of deep cracks and grooves generating ultrasonic signals. This method is only applicable for products in the material condition: — annealed; — light-annealed; — light-drawn; — soft annealed.
4.3 Test equipment Ultrasonic equipment with pulse echo technique shall be used as described in EN ISO 16810:2014, 5.4. It is recommended to use test equipment according to EN 12668-1 and EN 12668-2. Ultrasonic testing and result analysis typically is done in an automated system against pre-determined criteria without human intervention (see Figure 1). When driving mechanics are used for the sample they shall be as vibration-free as possible. In general, if samples will be moved during the test (in axial direction or by rotation), it is required to keep the distance between sample and probe constant. Probes within the frequency range of 1 MHz to 60 MHz shall be applied. Coupling of the ultrasonic waves is provided by a coupling fluid, e.g. water or oil (see EN ISO 16810:2014, 6.3). For constant coupling an automated ultrasonic testing is recommended to apply the immersion technique. Tube-curvature (ovality, roundness) is not to be considered as the ultrasonic spot size (focal point) is very small. Parasitic echoes and echoes of discontinuities should be eliminated from the ultrasonic evaluation process by adequate means.
4.4 Procedure Prepare sample (cut to length, clean if necessary). Adjust instrument once per day before the first test (see Clause 5). Couple sample with transducer by using a coupling fluid. Estimate the grain size by using the reflection of ultrasonic waves on grain boundaries. The backscattered signals from the grains in the product are analysed in an A-scan presentation. The signals vary in dependence of the average grain size (see Figure 2).
5 Instrument adjustment The test equipment shall be adjusted previous to the test of samples using a reference sample in accordance with Clause 6. The control survey for adjustment of the ultrasonic equipment should be repeated at least every working day with the relevant reference sample. IMPORTANT — In the event of deviations during adjustment greater than ± 3 µm, the ultrasonic equipment shall be re-calibrated! If re-calibration is not successful, calibration according to Clause 6 shall be done again. All tubes tested since the last adjustment shall be considered as not been tested. 6 Reference samples and calibration Ultrasonic testing is a comparative method. Calibrations for every alloy or group of alloys (calibration- graph) considering the thickness are required. The reference samples shall represent the whole range of grain sizes as specified in the relevant product standard. The reference samples are tested in parallel: 1) with the ultrasonic technique, and 2) according to intercept procedure or planimetric procedure as described in EN ISO 2624. Test results of both methods shall be matched and this correlation of ultrasonic signals and grain size (calibration curve) is used as a basis for future ultrasonic testing and instrumental adjustment 7 Acceptance criteria The acceptance criteria are specified in the relevant product standards. In the event that the sample fails to meet the test requirements, the procedures for retest in the relevant product standard apply. Samples for retests shall be tested with one of the methods described in EN ISO 2624.BS EN 16090 pdf download.
