ISO INTERNATIONAL STANDARD 16828 First edition 2012-04-01 Non-destructive testing Ultrasonic testing Time-of-flight diffraction technique as a method for detection and sizing of discontinuities Essais non destructifs Controle par ultrasons - Technique de diffraction du temps de vol utilisée comme méthode de détection et de dimensionnementdesdiscontinuites Reference number ISO 16828:2012(E) @ISO2012 领翼国际无损检测学校--专注NDT人员国际讠 最新培训计划，点击网址：ww.ly-ndt.com ISO 16828:2012(E) COPYRIGHT PROTECTED DOCUMENT @ISO2012 IsO's memberbody in the country of the requester. ISO copyright office Case postale 56 . CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyright@iso.org Web www.iso.org Published in Switzerland = @IsO2012-All rights reserved 领翼国际无损检测学校--专注NDT人员国际认证，最新培训计划，点击网址：www.ly-ndt.com ISO 16828:2012(E) Contents Page Foreword. .V Introduction. 1 Scope.... 2 Normative references.. 3 Terms, definitions, symbols and abbreviations. 3.1 Terms and definitions ... 3.2 Abbreviations.... 3.3 Symbols.. General.. 4.1 Principle of the technique.... 4.2 Requirements for surface condition and couplant.. 4.3 Materials and process type .... 5 Qualification of personnel . 6 Equipment requirements ... 6.1 Uitrasonic equipment and display... 6.2 Ultrasonic probes .. 6.3 Scanning mechanism.... 7 Equipment set-up procedures 7.1 General .. 7.2 Probe choice and probe separation . 7.2.1 7.2.2 7.3 Time window setting ... 7.4 Sensitivity setting.. 7.5 Scan resolution setting... .10 7.6 Setting of scanning speed. 7.7 Checking system performance ... 8 Interpretation and analysis of data.. 8.1 Basic analysis of discontinuities... 8.1.1 8.1.2 Characterisation of discontinuities 10 8.1.3 Estimation of discontinuity position .. 11 8.1.4 .11 8.1.5 Estimation of discontinuity depth and height..... 8.2 Detailed analysis of discontinuities ....... 8.2.1 General .. 8.2.2 Additional scans.... 8.2.3 Additionalalgorithms. 14 9 Detection and sizing in complex geometries ... .14 10 Limitations of the technique. .14 10.1 General. 10.2 Accuracy and resolution... 15 10.2.1 10.2.2 Errors in the lateral position 10.2.3 Timing errors ... 15 10.2.4 Errors in sound velocity .15 10.2.5 Errors in probe centre separation 10.2.6 Spatial resolution ... .16 10.3 Dead zones.... 16 ISO 2012 - All rights reserved ili 领翼国际无损检测学校--专注NDT人员国际认证，最新培训计划，点击网址：www.ly-ndt.com