ISO INTERNATIONAL STANDARD 26843 First edition 2015-12-15 Metallic materials Measurement of fracture toughness at impact loading rates using precracked Charpy-type test pieces Materiaux metalliques - Mesure de la tenacite d'eprouvettes type Charpy préfissurees soumises a un chargement d'impact Reference number IS0 26843:2015(E) ISO International Organization for Standardization ZHEJIANG INST OF STANDARDIZATION C1 5956617 @IS02015 HS unde nitted without license from IHS IS0 26843:2015(E) COPYRIGHT PROTECTED DOCUMENT IS0 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 [email protected] www.iso.org Internationai ibr DrganizationforStandardization Licensee-ZHEJIANG INST.OF STANDARDIZoISQ35 -All rights reserved networking permited without license from IHS IS0 26843:2015(E) Contents Page Foreword ..iv Introduction. .. 1 Scope. ..1 2 Normative references ..1 3 Symbols 4 Principle. ..3 5 Test specimens. .5 6 Testing machines. .6 7 Test procedures and measurements .6 7.1 General. .. 6 7.2 Impact velocity. .7 7.3 Time to fracture .7 7.4 Multiple specimen tests. .7 7.5 Single-specimen tests .7 7.6 Post-test crack length measurements. ..8 8 Evaluation of fracture mechanics parameters .8 9 Test report .9 9.1 Organization .9 9.2 Specimen, material, and test environment .9 9.2.1 Specimen description .9 9.2.2 Specimen dimensions. ..9 9.2.3 Material description. 9 9.2.4 Test environment 10 9.3 Fatigue precracking conditions 10 9.4 Test data qualification .10 9.4.1 Limitations. .10 9.4.2 Crack length measurements .10 9.4.3 Fracture surface appearance. .10 9.4.4 Resistance curves .10 9.4.5 Checklist for data qualification .10 9.5 Test results. .11 Annex A (normative) Test machines suitable for each test procedure ..12 Annex B (informative) Estimation of strain rate ..13 Annex C (normative) Dynamic evaluation of fracture toughness. ..14 Annex D (normative) Determination of resistance curves at impact loading rates by multiple specimen methods. ..19 Annex E (normative) Estimation of Jd-Aa R-curves using the normalization method ..21 Annex F (normative) Determination of characteristic fracture toughness value Jo,2Bd. ..24 Annex G (normative) Validity criteria. ..25 Annex H (normative) Determination of fracture toughness in terms of J-integral ..27 Annex I (informative) Example test reports ..29 Bibliography .34 ii icensee=ZHEJIANG INST OF STANDARDIZATION C1 5956617 d without license from IHS