ASTM_E_2818_-_11.pdf

Designation:E281811Standard Practice forDetermination of Quasistatic Fracture Toughness of Welds1This standard is issued under the fixed designation E2818;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This practice provides methods for preparing specimensfrom welds in metallic materials and interpreting subsequenttest results when used in conjunction with standards TestMethods E1290 and E1820 for the determination of fracturetoughness.The fatigue pre-cracking procedures included inthis practice may also be used to aid in preparing straightpre-cracks for weld specimens in accordance with Test MethodE1681.1.2 This practice draws heavily from ISO 15653:Metallicmaterials Method of test for the determination of quasistaticfracture toughness of welds.All references to ISO 12135 inthat test method should be replaced with the applicable ASTMTest Methods(E1820,E1290 or E1681).1.3 The recommended specimen is a single-edge bendSE(B)with width,W,equal to twice the specimen thickness,B.An alternate SE(B)specimen with W/B equal to one and aspan,S,to W ratio of 4 may be used but may produce differenttoughness values.A compact tension C(T)specimen may beused if it can be demonstrated that the analysis of resultsproperly accounts for weld-to-base metal strength mismatcheffects on fracture toughness.1.4 The recommended limitation on weld-to-base metalyield strength ratio is0.5,ysweldysbase,1.5(1)Undermatching within this limitation leads to conservativeestimates of fracture toughness,while overmatching maylead to an overestimation of the fracture toughness by up to10%.1.5 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E8/E8M Test Methods for Tension Testing of Metallic Ma-terialsE1290 Test Method for Crack-Tip Opening Displacement(CTOD)Fracture Toughness Measurement(Withdrawn2013)3E1681 Test Method for Determining Threshold Stress Inten-sity Factor for Environment-Assisted Cracking of MetallicMaterialsE1820 Test Method for Measurement of Fracture ToughnessE1823 Terminology Relating to Fatigue and Fracture Testing2.2 ISO Standard:4ISO 12135 Metallic materials Unified method of test forthe determination of quasistatic fracture toughnessISO 15653 Metallic materialsMethod of test for the deter-mination of quasistatic fracture toughness of welds3.Terminology3.1 Terminology of E1823 and ISO 15653 are applicable tothis test practice with the following additions.3.2 Definitions:3.2.1 base metal yield strengthThe base metal 0.2%offsetyield strengthysbase!is defined by testing tensile specimens perTest Method E8/E8M.3.2.1.1 DiscussionISO 15653 uses Rp0,2bto represent thebase metal yield strength.3.2.2 overmatchedAny weldment havingysweldysbase.13.2.3 test temperatureThe test temperature for tensilespecimens shall either be identical to the test temperature forthe fracture toughness specimens,or evidence shall be pro-vided to demonstrate that there is not an appreciable change in1This practice is under the jurisdiction ofASTM Committee E08 on Fatigue andFracture and is the direct responsibility of Subcommittee E08.07 on FractureMechanics.Current edition approved May 1,2011.Published July 2011.DOI:10.1520E2818-11.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from International Organization for Standardization(ISO),1,ch.dela Voie-Creuse,Case postale 56,CH-1211,Geneva 20,Switzerland,http:/www.iso.ch.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 the yield strength between the test temperature used for thetensile and fracture toughness tests.3.2.4 undermatchedAny weldment havingysweldysbase,13.2.5 weld metal yield strengthThe weld metal 0.2%offsetyield strengthysweld!is defined by testing tensile specimens perTest Method E8/E8M.3.2.5.1 DiscussionISO 15653 uses Rp0,2wto represent theweld metal yield strength.4.Summary of Practice4.1 This test practice complements ISO 15653 for thequasistatic fracture toughness testing of welds.When testingwelds,it is important that the crack tip sample the region andmicrostructure of interest.Procedures given in ISO 15653 forselecting a specimen orientation,positioning of the fatigueprecrack relative to the weld or heat affected zone(HAZ),andverif