Josef Krautkrämer Herbert Krautkrämer

Ultrasonie Testing of Materials Third Edition

in Collaboration with

W Grabendörfer . M. Gregor . L. Nildas R. Frielinghaus . W Kaule . H. Schlemm U. Schlengermann . H. Steiger

Translation of the Third Revised German Edition

Springer-Verlag Berlin Heidelberg GmbH 1983

Dr. rer. nato Josef Krautkrämer Dr. rer. nato Herbert Krautkrämer

Cologne

Werner Grabendorfer, Dr. phil. Manfred Gregor, Dr.-Ing. Ludwig Niklas, Dr. phil. Rainer Frielinghaus, Dr.-Ing. Walter Kaule, Dipl.-Ing. Hans Schlemm, Dr. rer. nato Udo Schlengermann Helmut Seiger, Dr. rer. nato

Cologne

Translated from: WerkstoffprUfung mit Ultraschall, 3. Auf\. 1975

Translated by Dip\.-Ing. B. W. Zenzinger, Pretoria, South Africa in consultation with Dr. J. Krautkrämer, Cologne, and John E. Bobbin, Stratford, Conn., USA

With 509 figures and 10 diagrams

Library of Congress Cataloging in Publication Data. Krautkrämer, Jose f. Ultrasonic testing of ma­terlals. Translation of Werkstoffpriifung mit Ultraschall. Bibliography: p. 1- Ultrasonic testing. I. Krautkrämer, Herbert, joint author. II. Title. TA417.4.K713 1976 620.1'1274 76·12561-'fhis work Is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprintIng, re·use of illustraHons, broadcasting, repro­duction by photocopying machine or similar means, and storage in data banks. "Under § 54 of the Herman Copyright Law where copies are made for other than private nse, a fee Is payable to the publisher , the amount of the fee to be determlned by agreement with the publlsher. ® by Springer·Verlag Berlin Heidelberg 1969, 1977 and 1983 Originally published by Springer·Verlag Berlin Heidelberg New York Io 1983 Softcover reprlot oftbe hardcover 3rd edition 1983

"The use of registered names, trademarks, etc. In this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective Iaws and regulatlons and therefore .free for general use. :2061/3020 - li 4 3 2 l O

ISBN 978-3-662-02359-4 ISBN 978-3-662-02357-0 (eBook)DOI 10.1007/978-3-662-02357-0

Preface to the Third Edition

The amendments of this third English edition with respect to the second one concern beside some printing errors the replacement of some pictures in part D by more modern ones and updating the list of stand­ards to the state of the fourth German edition.

Cologne, January 1983 J OSEF KRAUTKRÄMER

Preface to the Second Edition

This seeond English edition is based on the third German edition. In view of most recent teehnologieal advanees it has beeome neeessary in many instanees to supplement the seeond German edition and to revise some parts completely.

In addition to piezo-eleetric methods, others are now also extensively diseussed in Chapter 8. As for the intensity method, ultrasonie holo­graphy is treated in the new Seetion 9.4. In Part B, for reasons of syste­maties, the resonanee method has been ineluded under transit-time methods. It appeared neeessary to elaborate in greater detail the defini­tion of the properties of pulse-echo testing equipment and their measure­ments (10.4). The more recent findings of pulse speetroscopy (5.6) and sound-emission analysis (12) are mentioned only in passing because their significanee is still controversial. Apart from numerous additions, partieularly those coneerning automatie testing installations, Part C also eontains a new chapter whieh deals with tests on nu eIe ar reactors (28), as weIl as abrief diseussion of surfaee-hardness tests (32.4). It beeame impossible to include a critieal analysis of the principal standards in Chapter 33. A few are mentioned, however, where the most important subjeets (e.g., the testing of welded joints in Chapter 26) are discussed, while others are only tabulated in Chapter 33.

The present, vastly inereased literature made bibliographieal seleetion rather diffieult. Consequently, we wish to apologize to any authors whose reports may have been omitted beeause of limitations governing the size of this volume.

VI Preface

We wish to express our gratitude .to the publishers for their under­standing and for their excellent cooperation in the preparation of this second English edition. The original authors also wish to thank their new co-workers who have been responsible for various additions, as weIl as the other contributors, too numerous to mention, who supplied valuable information.

Our thanks are also due to B. W. Zenzinger, Pretoria, South Africa, who also translated this edition from German into English and to John E. Bobbin of Stratford, Connecticut, for his assistance.

Cologne, March 1977 JOSEF. KRAU:rKRÄMER

HERBER~ KRAU~KRÄMER

Contents

Introduction ............................................... 1

PartA Physical Principles 01 Ultrasonic Testing 01 Materials

1. Waves ................................................. 5

1.1 Oscillations and Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Modes and Forms of Waves .. . . .. . . .. . .. . . .. .. . ... . . 8 1.3 Composite and Standing Waves. Interference ......... 12 1.4 Formulas and Numerical Data ...................... 17

2. Plane Sound Waves on Boundaries ........................ 23

2.1 Perpendicular Incidence on Single, Plane Interfaces. . . . 23 2.2 Perpendicular Incidence on Multiple Interfaces. Plate

and Gap.......................................... 26 2.3 The Law of Refraction ............................. 30 2.4 The Acoustic Pressure Values at Boundaries .......... 32 2.5 Reflection in a Right-Angled Edge and in a Corner. .... 40 2.6 Splitting of Surface and Boundary Waves ............ 42 2.7 Acoustic Propagation in Plates. Plate Waves . . ... . .... 43

3. Geometrie UItrasonic Optics .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

3.1 Limits of Validity ................................. 46 3.2 Acoustic Pressure Distance Law for Spherical and Cylin-

drical Waves . .. . .. . .. .. . .. .. . .. . .. . .. ... . .. ... .... 47 3.3* Reflection and Refraction of Spherical Waves on Plane

Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 48 3.4* Curved Interfaces as Concave Mirrors and Lenses . ... .. 51 3.5* Spherical Waves in Hollow and Solid Cylinders . .. . .. .. 57

* The seetions marked with an asterisk are less important for beginners.

VIII Contents

4. Wave Physics of Sound Field. The Sound Beam 62

4.1 Elementary Description ............................ 62 4.1.1 Flat Oscillators ............................. 62 4.1.2* Focussed Radiators ........................ " 75

4.2* Zone Construction of Sound Fields . . . . . . . . . . . . . . . . . . . 80 4.3 Sound Field by Non-Uniform Excitation of the Radiator

and Pulse Excitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

5. Echo and Shadow of an Obstacle in the Sound Field . . . . . . . . . 90

5.1 Echo of a Plane Reflector at Right Angles to the Axis of the Sound Beam of a Piston Oscillator (DOS Diagram) 90

5.2 Shadow of a Circular Disc Reflector at Right Angles to the Acoustic Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 96

5.3 Obliquely Oriented Flaws. Reflection by Edge Waves .. 98 5.4 Other Types of Reflectors .......................... 101 5.5 Natural Reflectors. Roughness ...................... 102 5.6* Effect of the Reflector on the Frequency Distribution of

the Pulse ......................................... 105

6. Attenuation of Ultrasonic Waves in Solids ................. 107

6.1 Absorption and Scattering .......................... 107 6.2* Attenuation in Metals. Anisotropy and Cast Structure .. 113

7. Piezoelectric Methods of Generation and Reception of Ultrasonic Waves ................................................. 119

7.1 The Piezoelectric Effect ............................ 119 7.2 The Piezoelectric Plate as 'fransmitter and Receiver of

Ultrasonic Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 124 7.3* The Piezoelectric Transducer with Pulse Excitation .... 132 7.4 Piezoelectric Materials ............................. 142

8. * Other Methods for Transmitting and Receiving Ultrasound ... 150

8.1 Mechanical Effects ................................. 151 8.2 Thermal Effects ................................... 151 8.3 Electrostatic Methods .............................. 154 8.4 Methods Based on Non-Magnetic Effects of the Electric

Current .......................................... 156 8.5 Electrodynamic Methods ........................... 157 8.6 Magnetostrictive Methods .......................... 162 8.7 Optical Methods .................................... 165

Contents IX

PartB Methods and Instruments lor the Ultrasonie Testing 01 Materials

9. Intensity Methods ....................................... 174

9.1 Principle, Classification and Differentiation as Compared with the Transit-Time Methods ....................... 174

9.2 Instruments for Intensity Measurements . . . . . . . . . . . . .. 179 9.3 Instruments for Sound-Image Methods ............... 181 9.4* Ultrasonic Holography ............................. 185

10. Pulse-Echo Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 193

10.1 History and Principles ............................. 193 10.2 Construction and Mode of Operation of a Pulse-Echo

Instrument ....................................... 197 10.2.1 Sweep Section with CR Tube ................ 198 10.2.2 Transmitter Unit ........................... 202 10.2.3 The Amplifier .............................. 205 10.2.4 Distance Scale and Time Markers ............. 214 10.2.5 Noise Suppression .......................... 218

10.3 The Probes ....................................... 219 10.3.1 Normal Probes ............................. 219 10.3.2 Angle Probes .............................. 228

10.4 Properties of Pulse-Echo Instruments and Probes. . . . .. 235 10.4.1 Properties of the Image Unit ................ 236 10.4.2 Properties of the Amplifier .................. 237 10.4.3 Properties of the Sound Field ................ 241 10.4.4 The Distance Adjustment ................... 244

10.5 Instruments of the Pulse-Echo Method ............... 245 10.6 Methods and Auxiliary Instruments for Electronic Data

Processing ........................................ 247 10.7 Methods and Auxiliary Instruments for Documentation. 252 10.8* Frequency-Modulation Method ...................... 263

11. Transit-Time Method .................................... 265

11.1 Transit-Time Methods with Continuous Sound (Reso-nance Method). Principles and Instruments ........... 265

11.2 Transit-Time Methods Using Pulses .................. 269 11.2.1 Comparative Method. Interferometer ......... 269 11.2.2 Frequency Measuring Methods ............... 272 11.2.3 Electronic Transit-Time Measurements ........ 278 11.2.4* Phase Measuring Method .................... 286

X Contents

12.* Sound Emission Analysis ................................ 287

parte General Testing Technique

13. Coupling, Choice of Probe and :M:easuring Frequency ......... 289

13.1 Condition and Preparation of Surface ................ 289 13.2 Curved Surfaces ................................... 290 13.3 Coupling :M:edia ................................... 293 13.4 Checking of Coupling .............................. 296 13.5 Coupling through Intermediate Layers ............... 297 13.6 Ultrasonie Frequency and Type of Probe ............. 304

14. Interference Effect of Boundaries. Complex Sound Paths and Screen Patterns ......................................... 307

14.1 Effect on the Sound Field by Boundaries Parallel to the Beam Axis ....................................... 307

14.2 Secondary Echoes Produced by Split-Off Transverse Waves .................................... , ...... 311

14.3 Triangle Reflections ............................... 314 14.4 61° Reflection ..................................... 316 14.5 Screen Patterns when Testing a Plate ................ 318 14.6 Interfering Echoes through Surface Waves ............ 324

15. Testing by :M:eans of Transverse, Surface and Plate Waves ... 326

15.1 Transverse Waves ................................. 326 15.2 Surface Waves .................................... 332 15.3 Plate Waves ...................................... 336

16. Determination of Shape and Size of Flaws . . . . . . . . . . . . . . . . .. 338

17. Interference by External High-Frequency and Ultrasonic Sources ................................................ 344

18. Organization of the Test. Staff and Training Problems ....... 348

19. Testing Installations and Evaluation of Test Results ......... 353

Contents XI

Part D Special Test Problems

20. Flaw Detection on Metallic Specimens 357

20.1 Heavy Forgings ................................... 357 20.2 Worked Parts of Machines .......................... 371

21. Railway Material ....................................... 381

21.1 Axles ............................................ 381 21.2 Rails .................................... " ........ 388 21.3 MisceIlaneous Railway Material ..................... 396

22. Plate and Strip ......................................... 399

22.1 Medium and Heavy Plate .......................... 399 22.2 Strip and Sheet ................................... 413

23. Semi-Finished Products: Rods, BiIlets and Wires ............ 427

23.1 Rod Material ..................................... 427 23.2 BiIlets ........................................... 435 23.3 Wires ............................................ 437

24. Pipes and Cylinders ....... .'............................. 439

25. Castings ............................................... 458

26. Welded Joints .......................................... 466

26.1 Butt-Welded Joints ................................ 466 26.1.1 Testing Method, General .................... 466 26.1.2 Plate Thickness, Beam Angle and Testing Fre-

quency ............... , ... " .... '" ..... '" 470 26.1.3 Flaw-Locating Methods ..................... 473 26.1.4 Nature, Shape and Size of Defect ............. 481 26.1.5 Recording and Automation .................. 486

26.2 Fillet Welds ...................................... 496 26.3 Spot Welds ....................................... 500 26.4 Other Forms of Welded Joints ...................... 501

27. Joints Produced by Rivetting, Glueing and Shrinking ........ 505

27.1 Rivet-Hole Testing ................................ 505 27.2 Laminar Joints Produced by Soldering, Brazing, Glueing,

Plating, etc. ...................................... 507 27.3 Shrink Fits ....................................... 516

XII Contents

28. Nuclear Reactors 518

29. Metals and their Special Testing Problems. . . . . . . . . . . . . . . . .. 526

29.1 Steel ............................................. 526 29.2 Cast Steel ........................................ 528 29.3 Cast Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 529 29.4 Light Metals ...................................... 536 29.5 Copper and Copper Alloys .......................... 540 29.6 Other Non-Ferrous Metals .......................... 541 29.7 Sintered Metals ................................... 543

30. Testing Problems on Non-Metallic Specimens ............... 545

30.1 Ceramic Materials and Glass ........................ 545 30.2 Plastics .......................................... 551 30.3 Rubber .......................................... 554 30.4 Rock, Abrasive Wheels and Carbon .................. 555 30.5 Concrete ......................................... 558 30.6 Woodand Leather ................................. 563 30.7 Bacon and Meat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 565

31. Determination of Position, Shape and Level ................ 569

32. Measuring Methods Using Ultrasound ...................... 573

32.1 Measutement of Wall and Layer Thicknesses .......... 573 32.2 Measurement of Acoustic Velocity ................... 580 32.3 Measurement of Attenuation and Scatter of Sound ..... 587 32.4 Measurement of Surface Hardness ................... 595

33. Standardization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 598

Appendix. Formulas, Diagrams and Tables . . . . . . . . . . . . . . . . . . .. 605

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 622

Index ..................................................... 659