ASTM-E1820 › Historical Revision Information
Standard Test Method for Measurement of Fracture Toughness
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Scope
1.1 This test method covers procedures and guidelines for the determination of fracture toughness of metallic materials using the following parameters: K, J, and CTOD (δ). Toughness can be measured in the R-curve format or as a point value. The fracture toughness determined in accordance with this test method is for the opening mode (Mode I) of loading.
1.2 The recommended specimens are single-edge bend, [SE(B)], compact, [C(T)], and disk-shaped compact, [DC(T)]. All specimens contain notches that are sharpened with fatigue cracks.
1.2.1 Specimen dimensional (size) requirements vary according to the fracture toughness analysis applied. The guidelines are established through consideration of material toughness, material flow strength, and the individual qualification requirements of the toughness value per values sought.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Significance and Use
5.1 Assuming the presence of a preexisting, sharp, fatigue crack, the material fracture toughness values identified by this test method characterize its resistance to: (1) fracture of a stationary crack, (2) fracture after some stable tearing, (3) stable tearing onset, and (4) sustained stable tearing. This test method is particularly useful when the material response cannot be anticipated before the test. Application of procedures in Test Method E1921 is recommended for testing ferritic steels that undergo cleavage fracture in the ductile-to-brittle transition.
5.2 The following cautionary statements are based on some observations.
5.2.1 Particular care must be exercised in applying to structural flaw tolerance assessment the fracture toughness value associated with fracture after some stable tearing has occurred. This response is characteristic of ferritic steel in the transition regime. This response is especially sensitive to material inhomogeneity and to constraint variations that may be induced by planar geometry, thickness differences, mode of loading, and structural details.
Keywords
crack initiation; crack-tip opening displacement; CTOD; ductile fracture; elastic-plastic fracture toughness; fracture instability; J-integral; K
To find similar documents by ASTM Volume:
03.01 (Metals -- Mechanical Testing; Elevated and Low-Temperature Tests; Metallography)
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Document Number
ASTM-E1820-11e2
Revision Level
2011(E2) EDITION
Status
Superseded
Modification Type
Editorially changed
Publication Date
June 1, 2013
Document Type
Test Method
Page Count
58 pages
Committee Number
E08.07