1、Designation: E399 092E399 12Standard Test Method forLinear-Elastic Plane-Strain Fracture Toughness KIc ofMetallic Materials1This standard is issued under the fixed designation E399; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he 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.This standard has been approved for use by agencies of the Department of Defense.1 NOTEEq A3.4, Eq A4.4, Eq A5.4, and E
3、q A6.11 were editorially corrected in May 2010.2 NOTE11.2 and 11.4 were editorially corrected in December 2010.1. Scope1.1 This test method covers the determination of fracture toughness (KIc) of metallic materials under predominantlylinear-elastic, plane-strain conditions using fatigue precracked s
4、pecimens having a thickness of 1.6 mm (0.063 in.) or greater2subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force. Details of test apparatus, specimenconfiguration, and experimental procedure are given in the Annexes.NOTE 1Plane-strain fracture toughness t
5、ests of thinner materials that are sufficiently brittle (see 7.1) can be made using other types of specimens (1).3There is no standard test method for such thin materials.1.2 This test method is divided into two parts. The first part gives general recommendations and requirements for KIc testing.The
6、 second part consists of Annexes that give specific information on displacement gage and loading fixture design, specialrequirements for individual specimen configurations, and detailed procedures for fatigue precracking. Additional annexes areprovided that give specific procedures for beryllium and
7、 rapid-force testing.1.3 General information and requirements common to all specimen configurations:SectionReferenced Documents 2Terminology 3Stress-Intensity Factor 3.1.1Plane-Strain Fracture Toughness 3.1.2Crack Plane Orientation 3.1.3Summary of Test Method 4Significance and Use 5Significance 5.1P
8、recautions 5.1.1-5.1.5Practical Applications 5.2Apparatus (see also 1.4) 6Tension Machine 6.1Fatigue Machine 6.2Loading Fixtures 6.3Displacement Gage, Measurement 6.4Specimen Size, Configurations, and Preparation (seealso 1.5)7Specimen Size Estimates 7.1Standard and Alternative Specimen Configuratio
9、ns 7.2Fatigue Crack Starter Notches 7.3.1Fatigue Precracking (see also 1.6) 7.3.2Crack Extension Beyond Starter Notch 7.3.2.2General Procedure 8Specimen MeasurementsThickness 8.2.1Width 8.2.21 This test method is under the jurisdiction of ASTM Committee E08 on Fatigue and Fracture and is the direct
10、responsibility of Subcommittee E08.07 on FractureMechanics.Current edition approved July 1, 2009Nov. 15, 2012. Published August 2009January 2013. Originally approved in 1970. Last previous edition approved in 20082009 asE399 08.E399 092. DOI: 10.1520/E0399-09E02.10.1520/E0399-12.2 For additional inf
11、ormation relating to the fracture toughness testing of alumi inum alloys, see Practice B645.3 The boldface numbers in parentheses refer to the list of references at the end of this standard.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indicati
12、on of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be consi
13、dered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1SectionCrack Size 8.2.3Crack Plane Angle 8.2.4Specimen TestingLoading Rate 8.3Test Record 8.4Calculation and Interpretation of Results 9Test Record Analysis 9
14、.1Pmax/PQ Validity Requirement 9.1.3Specimen Size Validity Requirements 9.1.4Reporting 10Precision and Bias 111.4 Specific requirements related to test apparatus:Double-Cantilever Displacement Gage Annex A1Testing Fixtures Annex A2Bend Specimen Loading Fixture Annex A2.1Compact Specimen Loading Clev
15、is Annex A2.21.5 Specific requirements related to individual specimen configurations:Bend Specimen SE(B) Annex A3Compact Specimen C(T) Annex A4Disk-Shaped Compact Specimen DC(T) Annex A5Arc-Shaped Tension Specimen A(T) Annex A6Arc-Shaped Bend Specimen A(B) Annex A7E399 1221.6 Specific requirements r
16、elated to special test procedures:Fatigue Precracking KIc Specimens Annex A8Hot-Pressed Beryllium Testing Annex A9Rapid-Force Testing Annex A101.7 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.8 This standard does not pur
17、port to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:4B909
18、 Guide for Plane Strain Fracture Toughness Testing of Non-Stress Relieved Aluminum ProductsB645 Practice for Linear-Elastic PlaneStrain Fracture Toughness Testing of Aluminum AlloysE4 Practices for Force Verification of Testing MachinesE8/E8M Test Methods for Tension Testing of Metallic MaterialsE17
19、7 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE337 Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)E456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study to Determine
20、the Precision of a Test MethodE1820 Test Method for Measurement of Fracture ToughnessE1823 Terminology Relating to Fatigue and Fracture TestingE1921 Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range3. Terminology3.1 Definitions:Terminology E1823
21、is applicable to this test method:3.1.1 stress-intensity factor, K,KI, KII, KIII FL3/2magnitude of the ideal-crack-tip stress field (a stress-field singularity), fora particular mode of crack displacement, in a homogeneous, linear-elastic body.3.1.1.1 K is a function of applied force and test specim
22、en size, geometry, and crack size, and has the dimensions of force timeslength-3/2.3.1.1.2 Values of K for modes I, II, and III are given as:KI 5 limr0yy2pir!1/2# (1)KII5 limr0xy2pir!1/2# (2)KIII5 limr0yz2pir!1/2# (3)where r is the distance directly forward from the crack tip to the location where t
23、he significant stress is calculated.3.1.2 plane-strain fracture toughness, KIc FL-3/2the crack-extension resistance under conditions of crack-tip plane strain inMode I for slow rates of loading under predominantly linear-elastic conditions and negligible plastic-zone adjustment. The stressintensity
24、factor, KIc, is measured using the operational procedure (and satisfying all of the validity requirements) specified in TestMethod E399, that provides for the measurement of crack-extension resistance at the onset (2% or less) of crack extension andprovides operational definitions of crack-tip sharp
25、ness, onset of crack extension, and crack-tip plane strain.3.1.2.1 See also definitions of crack-extension resistance, crack-tip plane strain, and mode in Terminology E1823.3.1.3 crack plane orientationidentification of the plane and direction of crack extension in relation to the characteristicdire
26、ctions of the product. A hyphenated code defined in Terminology E1823 is used wherein the letter(s) preceding the hyphenrepresents the direction normal to the crack plane and the letter(s) following the hyphen represents the anticipated direction ofcrack extension (see Fig. 1).3.1.3.1 Wrought Produc
27、tsthe fracture toughness of wrought material depends on, among other factors, the orientation andpropagation direction of the crack in relation to the materials anisotropy, which depends, in turn, on the principal directions ofmechanical working and grain flow. Orientation of the crack plane shall b
28、e identified wherever possible. In addition, product form4 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.E399
29、 123(a) Rectangular SectionsSpecimens Aligned with Reference Directions(b) Rectangular SectionsSpecimens Not Aligned with Reference Directions(c) Cylindrical Bars and TubesL = direction of maximum grain flowR = radial directionC = circumferential or tangential directionE399 124FIG. 1 Crack Plane Ide
30、ntificationE399 125shall be identified (for example, straight-rolled plate, cross-rolled plate, pancake forging, and so forth) along with materialcondition (for example, annealed, solution treated plus aged, and so forth). The user shall be referred to product specifications fordetailed processing i
31、nformation.3.1.3.2 For rectangular sections, the reference directions are identified as in Fig. 1(a) and Fig. 1(b), which give examples forrolled plate. The same system is used for sheet, extrusions, and forgings with nonsymmetrical grain flow.L = direction of principal deformation (maximum grain fl
32、ow)T = direction of least deformationS = third orthogonal direction3.1.3.3 Using the two-letter code, the first letter designates the direction normal to the crack plane, and the second letter theexpected direction of crack propagation. For example, in Fig. 1(a), the T-Lspecimen fracture plane norma
33、l is in the width directionof a plate and the expected direction of crack propagation is coincident with the direction of maximum grain flow (or longitudinal)direction of the plate.3.1.3.4 For specimens tilted in respect to two of the reference axes as in Fig. 1(b), crack plane orientation is identi
34、fied by athree-letter code. The designation L-TS, for example, indicates the crack plane to be perpendicular to the principal deformation(L) direction, and the expected fracture direction to be intermediate between T and S. The designation TS-L means that the crackplane is perpendicular to a directi
35、on intermediate between T and S, and the expected fracture direction is in the L direction.3.1.3.5 For cylindrical sections, where grain flow can be in the longitudinal, radial or circumferential direction, specimenlocation and crack plane orientation shall reference original cylindrical section geo
36、metry such that the L direction is always theaxial direction for the L-R-C system, as indicated in Fig. 1(c), regardless of the maximum grain flow. Note that this is a geometrybased system. As such, the direction of maximum grain flow shall be reported when the direction is known.NOTE 2The same syst
37、em is useful for extruded or forged parts having circular cross section. In most cases the Ldirection corresponds to the directionof maximum grain flow, but some products such as pancake, disk, or ring forgings can have the R or C directions correspond to the direction of maximumgrain flow, dependin
38、g on the manufacturing method.L = axial directionR = radial directionC = circumferential or tangential direction3.1.3.6 In the case of complex structural shapes, where the grain flow is not uniform, specimen location and crack planeorientation shall reference host product form geometry and be noted
39、on component drawings.3.1.3.7 Non-Wrought Productsfor non-wrought products, specimen location and crack plane orientation shall be defined onthe part drawing. The result of a fracture toughness test from a non-wrought product shall not carry an orientation designation.3.1.3.8 Discussionwhen products
40、 are to be compared on the basis of fracture toughness, it is essential that specimen locationand orientation with respect to product characteristic directions be comparable and that the results not be generalized beyond theselimits.3.2 Definitions of Terms Specific to This Standard:3.2.1 crack mout
41、h opening displacement (CMOD), Vm Lcomponent of clip gage displacement taken at the crackstarter-notch mouth.3.2.2 stress-intensity factor rate, K (FL-3/2 t-1)change in stress-intensity factor, K, per unit time.4. Summary of Test Method4.1 This test method covers the determination of the plane-strai
42、n fracture toughness (KIc) of metallic materials byincreasing-force tests of fatigue precracked specimens. Force is applied either in tension or three-point bending. Details of the testspecimens and experimental procedures are given in the Annexes. Force versus crack-mouth opening displacement (CMOD
43、) isrecorded either autographically or digitally. The force at a 5 % secant offset from the initial slope (corresponding to about 2.0 %apparent crack extension) is established by a specified deviation from the linear portion of the record (1). The value of KIc iscalculated from this force using equa
44、tions that have been established by elastic stress analysis of the specimen configurationsspecified in this test method. The validity of the KIc value determined by this test method depends upon the establishment of asharp-crack condition at the tip of the fatigue crack in a specimen having a size a
45、dequate to ensure predominantly linear-elastic,plane-strain conditions. To establish the suitable crack-tip condition, the stress-intensity factor level at which specimen fatigueprecracking is conducted is limited to a relatively low value.4.2 The specimen size required for test validity increases a
46、s the square of the materials toughness-to-yield strength ratio.Therefore a range of proportional specimens is provided.5. Significance and Use5.1 The property KIc determined by this test method characterizes the resistance of a material to fracture in a neutralenvironment in the presence of a sharp
47、 crack under essentially linear-elastic stress and severe tensile constraint, such that (1) thestate of stress near the crack front approaches tritensile plane strain, and (2) the crack-tip plastic zone is small compared to thecrack size, specimen thickness, and ligament ahead of the crack.E399 1265
48、.1.1 Variation in the value of KIc can be expected within the allowable range of specimen proportions, a/W and W/B.KIc mayalso be expected to rise with increasing ligament size. Notwithstanding these variations, however, KIc is believed to represent alower limiting value of fracture toughness (for 2
49、 % apparent crack extension) in the environment and at the speed and temperatureof the test.5.1.2 Lower values of KIc can be obtained for materials that fail by cleavage fracture; for example, ferritic steels in theductile-to-brittle transition region or below, where the crack front length affects the measurement in a stochastic mannerindependent of crack front constraint. The present test method does not apply to such materials and the user is referred to TestMethod E1921 and E1820. Likewise this test method does not apply to hi
