TENSTAND - WORK PACKAGE 1 - FINAL REPORT CONTRACT N° : G6RD-CT-2000-00412 PROJECT N° : GRD1-2000-25021 ACRONYM : TENSTAND TITLE : Tensile Testing of Metallic Materials: A Review PROJECT CO-ORDINATOR : NPL Management Ltd PARTNERS : National Physical Laboratory, Teddington, UK INSTRON, High Wycombe, UK BAM, Berlin, Germany ZWICK, Ulm, Germany Denison Mayes Group, Leeds, UK Thyssen Krupp Stahl, Duisburg, Germany ARCELOR, Florange, France ISQ-Instituto de Soldadura e Qualidade, Oeires, Portugal University of Strathclyde, Glasgow, UK Trinity College, Dublin, Ireland AGH, Kraków, Poland AUTHORS : Malcolm S Loveday, Tom Gray and Johannes Aegerter REPORTING PERIOD: From 1st February 2001 TO 30th April 2004 PROJECT START DATE : 1st February 2001 DURATION : 39 months Date of issue of this report : April 2004 Project funded by the European Community under the ‘Competitive and Sustainable Growth’ Programme (1998- 2002) 07/10/05 Rev 10 by LOVEDAY,GRAY & Aegerter Tensile test of Metallic Materials : A Review TENSTAND (M.S.L) 1 Tensile Testing of Metallic Materials: A Review. By Malcolm S Loveday,1 Tom Gray2 and Johannes Aegerter3 (April 2004) 1. Beta Technology Consultant, c/o National Physical Laboratory, Teddington, Middlesex, TW11 0LW, UK 2. Dept. Mechanical Engineering, University of Strathclyde, Glasgow, Scotland, G1 1XJ 3. Hydro Aluminium RDB, Georg-von-Boeselager Str 21, 53117 Bonn Postfach 24 68, 53014 Bonn, Germany [ See Foreword] Abstract The strength of a material under tension has long been regarded as one of the most important characteristics required for design, production quality control and life prediction of industrial plant. Standards for tensile testing are amongst those first published and the development of such Standards continues today. The EU funded project TENSTAND (2000-2004) addressed a) the issues of computer controlled tensile testing, b) validation of tensile software, c) the issues of speed of testing and d) the measurement of Modulus with a view to providing a sound technical basis for further development of the Standard. This review summarises a selection of published literature relating to tensile testing, starting with a review of historical publications through to the latest literature published on the subject. Note : This Review does not include the final results of the TENSTAND Project which will be published elsewhere. Further information about the project may be found on the following web site: http://www.npl.co.uk/npl/cmmt/projects/tenstand/ 07/10/05 Rev 10 by LOVEDAY,GRAY & Aegerter Tensile test of Metallic Materials : A Review TENSTAND (M.S.L) 2 FOREWORD This Review has been compiled primarily by Malcolm Loveday Tom Gray and Johannes Aegerter as part of Work Package 1 of the EU Funded Project ‘TENSTAND’ , Contract Number G6RD-2000-00412. The following persons also made significant contributions, either by supplying papers, diagrams and text, or by participation in the Work Package 1 meetings which were held in a) SOLLAC, Florange, France ( Feb 2002) b) ISQ, Lisbon, Portugal (Sept 2002), c) TCD, Dublin, Ireland ( Feb 2003) and d) USTRAT Glasgow (June 2003): NAME ORGANISATION COUNTRY J. Aegerter Hydro Aluminium Germany H. Bloching Zwick Germany M. Borsutzki TKS Germany J-L Geoffrey USINOR, France T. Gray USTRAT United Kingdom S. Keller Hydro Aluminium Germany H Klingelhöffer BAM Germany Halina Kusiak AGH Poland J. Kusiak AGH Poland S. Ledworuski BAM Germany R.D. Lohr INSTRON United Kingdom J. Lord NPL United Kingdom M. S. Loveday Beta Technology, NPL United Kingdom P Matuszyk AGH Poland T. McGinnley TCD, Ireland M..Murphy TCD, Ireland Valeriy Pidvysotskyy AGH Poland M. Pietrzyk AGH Poland C. Pinto ISQ Portugal M. Rides NPL United Kingdom H-M. Sonne TKS Germany S. Sothern CORUS United Kingdom Danuta Szeliga AGH Poland Jenny Tagallie USTRAT United Kingdom A. Wehrstedt, DIN Germany D. Wieser Hydro Aluminium Germany The original work package leader was Hans Martin Sonne, from TKS, who sadly retired due to ill health during the course of the project. The list of publication given in Appendix 1 was originally compiled by H-M Sonne & M. Borsutzki from TKS, Germany, from information supplied by various partners, and has been reformatted in date order. After starting the TENSTAND project the opportunity arose to include a partner from a ‘New Accession State’ ( NAS), a new country in the process of joining the European Union and thus Prof M Pietrzyk and his colleagues from AGH (Akademia Gorniczo-Hutnicza ), Kracow, Poland were invited to join the project. This enabled direct access to literature from some eastern bloc countries to be examined and thus a list of Polish papers relating to tensile testing, together with Abstracts and selected diagrams from key papers are included in Appendix 2a, and a similar list from the Russian literature is given in Appendix 2b. 07/10/05 Rev 10 by LOVEDAY,GRAY & Aegerter Tensile test of Metallic Materials : A Review TENSTAND (M.S.L) 3 CONTENTS Abstract.................................................................................................................2 Foreword…………………………………………………………………………………2 Contents………………………………………………………………………………….3 1. Introduction .......................................................................................................5 2. Symbols & Nomenclature……………………………………………………… .6 3. Historical Background .......................................................................................7 3.1 General ........................................................................................................8 3.2. Historical Background to Tensile Testing Standards.................................10 4. Standards: Recent Developments ..................................................................12 5. Alignment & Gripping .....................................................................................14 5.1 Gripping Systems …………………………………………………………….12 5.2 Alignment……………………………………………………………………….12 5.3 Strain rate Variations ………………………………………………… …….14 6. Testpiece Geometry.......................................................................................19 7. Speed & Control of Testing............................................................................21 7.1 Background……………………………………………………………………….17 7.2 Developments in testing Machine Technology ………………………………18 7.3 Effects of testing rates on properties ………………………………………….19 7.3.1 Results before servo control ( pre 1970) ………………………… ….21 7.3.2 Results from servo controlled machines …………………………… ….22 8. Uncertainty of Measurement..........................................................................29 9. Round Robin Experiments .............................................................................30 10. Measuring Systems & Data Recording ........................................................35 11. Other Issues 11.1 Software validation……………………………………………………… 29 11.2 Modulus Measurement………………………………………………….. 30 11.3 r & n measurements…………………………………………………… 31 12. Discussion …………………………………………………………………………34 13. Conclusions .................................................................................................45 14. Acknowledgements......................................................................................38 15. References.................................................................................................38 15.1 STANDARDS...........................................................................................38 15.2 PAPERS & BOOKS .................................................................................40 Table 1 46 Figures …. 47 - 89 Appendices: ............................................................................................................ APPENDIX 1. List of Papers relating to Tensile Testing compiled during TENSTAND Project 90 -99 APPENDIX 2a. List of Papers relating to Tensile Testing compiled during NAS- TENSTAND Project a) Polish Papers………………………………… 100 - 124 APPENDIX 2b. List of Papers relating to Tensile Testing compiled during NAS- TENSTAND Project b) Russian Papers 125 - 145 APPENDIX 3: Precision of Tensile Testing and.............................................146 Estimation of Uncertainty of Measurement. ......................................................... 07/10/05 Rev 10 by LOVEDAY,GRAY & Aegerter Tensile test of Metallic Materials : A Review TENSTAND (M.S.L) 4 1. Introduction The strength of a material under tension has long been regarded as one of the most important characteristics required for design, production quality control and life prediction of industrial plant. Standards for tensile testing were among the earliest standards to be published and the development of such Standards continues today. The revised European Standard, EN 10002 Pt1, published in 2001, covering Tensile Testing, now recognises the dominance of computer controlled testing machines, but the systematic technological evidence on which such a Standard should be based is not currently available. The EU funded project ‘TENSTAND’ (2000-2004) seeks to address this deficiency by addressing: a) issues of computer controlled tensile testing, b) validation of tensile test software, c) issues of speed of testing, d) measurement of Modulus, all with a view to providing a sound technical basis for further development of the Standard. The project was given the acronym ‘TENSTAND’ from the words Tensile Standard. Further information about the project may be found on the following web site : http://www.npl.co.uk/npl/cmmt/projects/tenstand/ As part