Edited by Konrad Herrmann

Transcription

1 Edited by Konrad Herrmann ASM International Materials Park, Ohio

2 Copyright 2011 by ASM International All rights reserved No part of this book may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the written permission of the copyright owner. First printing, October 2011 Great care is taken in the compilation and production of this book, but it should be made clear that NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE GIVEN IN CONNECTION WITH THIS PUBLICATION. Although this information is believed to be accurate by ASM, ASM cannot guarantee that favorable results will be obtained from the use of this publication alone. This publication is intended for use by persons having technical skill, at their sole discretion and risk. Since the conditions of product or material use are outside of ASM s control, ASM assumes no liability or obligation in connection with any use of this information. No claim of any kind, whether as to products or information in this publication, and whether or not based on negligence, shall be greater in amount than the purchase price of this product or publication in respect of which damages are claimed. THE REMEDY HEREBY PROVIDED SHALL BE THE EXCLUSIVE AND SOLE REMEDY OF BUYER, AND IN NO EVENT SHALL EITHER PARTY BE LIABLE FOR SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES WHETHER OR NOT CAUSED BY OR RESULTING FROM THE NEGLIGENCE OF SUCH PARTY. As with any material, evaluation of the material under end-use conditions prior to specification is essential. Therefore, specific testing under actual conditions is recommended. Nothing contained in this book shall be construed as a grant of any right of manufacture, sale, use, or reproduction, in connection with any method, process, apparatus, product, composition, or system, whether or not covered by letters patent, copyright, or trademark, and nothing contained in this book shall be construed as a defense against any alleged infringement of letters patent, copyright, or trademark, or as a defense against liability for such infringement. Comments, criticisms, and suggestions are invited, and should be forwarded to ASM International. Prepared under the direction of the ASM International Technical Book Committee ( ), Michael J. Pfeifer, Chair. Special thanks to Sarup Chopra for additional translations. ASM International staff who worked on this project include Scott Henry, Senior Manager, Content Development and Publishing; Eileen De Guire, Senior Content Developer; Victoria Burt, Content Developer; Sue Sellers, Editorial Assistant; Bonnie Sanders, Manager of Production; Madrid Tramble, Senior Production Coordinator; and Diane Whitelaw, Production Coordinator. Library of Congress Control Number: ISBN-13: ISBN-10: SAN: ASM International Materials Park, OH Printed in the United States of America

3 Hardness Testing Principles and Applications Copyright 2011 ASM International Konrad Herrmann, editor All rights reserved. Contents Preface vii Chapter 1 The Fundamentals of Hardness Testing... 1 The History of Hardness Testing The Term Hardness Interrelationship Between Material Structure and Hardness Relationships Between Hardness and Other Mechanical Material Properties Hardness Unit and Traceability of the Hardness Measurement Summary EA Measurement Uncertainty Guideline for Brinell and Vickers Measurements EA Guideline for Determining Measurement Uncertainty During the Hardness Test According to the HRC Scale Chapter 2 Hardness Measurement of Metals Static Methods Rockwell ISO 6508 and ASTM E 18 Procedures Vickers ISO 6507, ASTM E92, and ASTM E384 Procedures Brinell ISO 6506 and ASTM E10 Procedures Knoop ISO 4545 and ASTM E284 Procedures Chapter 3 Dynamic Test Methods Introduction Theory Methods to Measure the Deformation Methods to Measure Energy Applications Outlook iii

4 iv / Contents Chapter 4 Hardness Testing of Metals Contactless and Other Nondestructive Methods Electromagnetic Impulse Method Photothermal Method Determining Hardening Depth by Ultrasound Scratch Hardness Testing Ultrasonic Contact Impedance (UCI) Procedure Checking the Hardness Testing Machines and Indenters Hardness Reference Blocks and Their Calibration Hardness Conversion According to ISO Capability of the Testing Equipment and Suitability of the Testing Method Chapter 5 Hardness Measurement of Plastics and Elastomers Test Procedures Testing Technique Applications Summary Chapter 6 Instrumented Indentation Test Introduction Contact Mechanics Test Method Required Checking of Test Equipment and Indenters Special Case: Testing of Layers Test Engineering Application Examples Measurement Uncertainty Determining the True Stress-Strain Curve of Materials Summary Chapter 7 Standardization General Comments on Standardization Historical Development of Materials Testing Standards Status of Standardization in the Field of Hardness Testing Index

5 Hardness Testing Principles and Applications Copyright 2011 ASM International Konrad Herrmann, editor All rights reserved. Preface Hardness testing is of immense importance for quality assurance in industry. Although the most widely used hardness test methods for metals Rockwell, Brinell, and Vickers were developed between 1900 and 1925, in the past ten years they have experienced numerous technical innovations leading to an increase in productivity and the accuracy of hardness tests. This publication on hardness testing provides, based on the state of standardization, an overview of the hardness testing of metals, plastics, rubber, and other materials. It reports on technical developments such as the introduction of image processing in the Brinell and Vickers methods, the adaptation of hardness testing machines to process-oriented testing conditions, and the development of highly accurate and efficient calibration methods. Most recently, guidelines have been worked out to determine the uncertainty of hardness measurements as a component of the ISO standards on hardness testing methods. With the aid of these guidelines, it is possible to simply and directly fulfill the requirement of the international standards that say each hardness measurement value must state its uncertainty. In contrast to the conventional Rockwell, Vickers, and Brinell hardness testing methods, which each produce a single hardness measurement value, the instrumented indentation test features a great amount of information on the elastic and plastic properties of the material. For a wide range of applications, including the nano, micro, and macro levels, the instrumented indentation test offers unique application possibilities. On thin and ultrathin layers with a layer thickness in the nanometer range, it presents a universal method for determining mechanical properties. On the other hand, the instrumented indentation test enables the determination of the indentation depth in the macro range, which is much more efficient than the conventional method of micro-vickers testing on the cross section of the specimen. In addition to the hardness testing of metals, the hardness testing of rubber and plastics has an equally great economic importance. As in the case of dynamic hardness testing, an essential feature is that in this area, predo- v

6 vi / Preface minantly portable hardness test devices are used. At the present time, great efforts are being made to increase the accuracy of the rubber and plastics hardness test as well as the dynamic hardness test by means of systematic calibrations of the portable testing devices. It is necessary to point out that the commercial products mentioned in this publication do not imply any recommendation and are not necessarily the best available products. I give my special thanks to Mrs. U. Baier-Blott, C. Charvieux, G. Froetel, and E. Jones from the PTB Translation Office for their reliable and accurate translation of the German manuscript of this book into English. This book, the articles of which have been written by a group of renowned experts in the field of hardness testing, addresses, above all, experts in materials testing and quality control, students of materials science, as well as technologists and design engineers in the metals and plastics processing industries. Konrad Herrmann Braunschweig, March 2010