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ASTM E1221-96(2002)

(Test Method)

Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic Steels

Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic Steels

SCOPE
1.1 This test method employs a side-grooved, crack-line-wedge-loaded specimen to obtain a rapid run-arrest segment of flat-tensile separation with a nearly straight crack front. This test method provides a static analysis determination of the stress intensity factor at a short time after crack arrest. The estimate is denoted K a. When certain size requirements are met, the test result provides an estimate, termed KIa, of the plane-strain crack-arrest toughness of the material.
1.2 The specimen size requirements, discussed later, provide for in-plane dimensions large enough to allow the specimen to be modeled by linear elastic analysis. For conditions of plane-strain, a minimum specimen thickness is also required. Both requirements depend upon the crack arrest toughness and the yield strength of the material. A range of specimen sizes may therefore be needed, as specified in this test method.
1.3 If the specimen does not exhibit rapid crack propagation and arrest, Ka  cannot be determined.
1.4 Values stated in inch-pound units are to be regarded as the standards. SI units are provided for information only.
1.5 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.

General Information

Status
Historical
Publication Date
09-Jun-1996
ICS
77.040.10 - Mechanical testing of metals
Technical Committee
E08 - Fatigue and Fracture
Drafting Committee
E08.07 - Fracture Mechanics
Current Stage
Ref Project

Relations

Replaces
ASTM E1221-96 - Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic Steels
Effective Date
10-Jun-1996
Replaced By
ASTM E1221-06 - Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic Steels
Effective Date
15-Jan-2006
Referred By
ASTM E1823-23 - Standard Terminology Relating to Fatigue and Fracture Testing
Effective Date
10-Jun-1996
Referred By
ASTM F3122-14(2022) - Standard Guide for Evaluating Mechanical Properties of Metal Materials Made via Additive Manufacturing Processes
Effective Date
10-Jun-1996

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ASTM E1221-96(2002) - Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic SteelsASTM E1221-96(2002) - Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic Steels
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ASTM E1221-96(2002) - Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, K<sub>Ia</sub>, of Ferritic Steels
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:E1221–96 (Reapproved 2002)
Standard Test Method for
Determining Plane-Strain Crack-Arrest Fracture Toughness,
1
K , of Ferritic Steels
Ia
This standard is issued under the fixed designation E1221; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
2
1. Scope E616 Terminology Relating to Fracture Testing
E1304 Test Method for Plane-Strain (Chevron Notch)
1.1 This test method employs a side-grooved, crack-line-
2
Fracture Toughness of Metallic Materials
wedge-loadedspecimentoobtainarapidrun-arrestsegmentof
flat-tensile separation with a nearly straight crack front. This
3. Terminology
test method provides a static analysis determination of the
3.1 Definitions:
stress intensity factor at a short time after crack arrest. The
3.1.1 Definitions in Terminology E616 are applicable to
estimate is denoted K . When certain size requirements are
a
this test method.
met, the test result provides an estimate, termed K ,ofthe
Ia
3.2 Definitions of Terms Specific to This Standard:
plane-strain crack-arrest toughness of the material.
3.2.1 conditional value of the plane-strain crack-arrest
1.2 The specimen size requirements, discussed later, pro-
−3/2
fracture toughness, K (FL )—the conditional value of K
Qa Ia
vide for in-plane dimensions large enough to allow the speci-
calculated from the test results and subject to the validity
men to be modeled by linear elastic analysis. For conditions of
criteria specified in this test method.
plane-strain, a minimum specimen thickness is also required.
3.2.1.1 Discussion—In this test method, side-grooved
Both requirements depend upon the crack arrest toughness and
specimens are used. The calculation of K is based upon
Qa
the yield strength of the material. A range of specimen sizes
measurements of both the arrested crack length and of the
may therefore be needed, as specified in this test method.
crack-mouth opening displacement prior to initiation of a
1.3 Ifthespecimendoesnotexhibitrapidcrackpropagation
fast-running crack and shortly after crack arrest.
and arrest, K cannot be determined.
a
−3/2
3.2.2 crack-arrest fracture toughness, K (FL )—the
a
1.4 Values stated in inch-pound units are to be regarded as
value of the stress intensity factor shortly after crack arrest.
the standards. SI units are provided for information only.
3.2.2.1 Discussion—The in-plane specimen dimensions
1.5 This standard does not purport to address all of the
must be large enough for adequate enclosure of the crack-tip
safety concerns, if any, associated with its use. It is the
plastic zone by a linear-elastic stress field.
responsibility of the user of this standard to establish appro-
3.2.3 plane-strain crack-arrest fracture toughness, K
Ia
priate safety and health practices and determine the applica-
−3/2
(FL )—the value of crack-arrest fracture toughness, K , for
a
bility of regulatory limitations prior to use.
acrackthatarrestsunderconditionsofcrack-frontplane-strain.
2. Referenced Documents 3.2.3.1 Discussion—The requirements for attaining condi-
tions of crack-front plane-strain are specified in the procedures
2.1 ASTM Standards:
2
of this test method.
E8 TestMethodsforTensionTestingofMetallicMaterials
−3/2
3.2.4 stressintensityfactoratcrackinitiation,K (FL )—
o
E23 Test Methods for Notched Bar Impact Testing of
2
the value of K at the onset of rapid fracturing.
Metallic Materials
3.2.4.1 Discussion—In this test method, only a nominal
E208 Test Method for Conducting Drop-Weight Test to
estimate of the initial driving force is needed. For this reason,
Determine Nil-DuctilityTransitionTemperature of Ferritic
2
K is calculated on the basis of the original (machined) crack
o
Steels
(ornotch)lengthandthecrack-mouthopeningdisplacementat
E399 Test Method for Plane-Strain Fracture Toughness of
2
the initiation of a fast-running crack.
Metallic Materials
4. Summary of Test Method
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE08onFracture 4.1 This test method estimates the value of the stress
Testing and is the direct responsibility of Subcommittee E08.07 on Linear-Elastic
intensity factor, K, at which a fast running crack will arrest.
Fracture.
This test method is made by forcing a wedge into a split-pin,
Current edition approved June 10, 1996. Published August 1996. Originally
whichappliesanopeningforceacrossthecrackstarternotchin
published as E1221–88. Last previous edition E1221–88.
2
Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1

---------------------- Page: 1 --------------
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4.1 The surface-crack tension (SCT) test is used to estimate the load-carrying capacity of simple sheet- or plate-like structural components having a type of flaw likely to occur in service. The test is also used for research purposes to investigate failure mechanisms of cracks under service conditions.  
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1.1 This practice covers the design, preparation, and testing of surface-crack tension (SCT) specimens. It relates specifically to testing under continuously increasing force and excludes cyclic and sustained loadings. The quantity determined is the residual strength of a specimen having a semielliptical or circular-segment fatigue crack in one surface. This value depends on the crack dimensions and the specimen thickness as well as the characteristics of the material.  
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1.3 This practice is limited to specimens having a uniform rectangular cross section in the test section. The test section width and length must be large with respect to the crack length. Crack depth and length should be chosen to suit the ultimate purpose of the test.  
1.4 Residual strength may depend strongly upon temperature within a certain range depending upon the characteristics of the material. This practice is suitable for tests at any appropriate temperature.  
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1.6 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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6.2.1 Expressing CCI time, t0.2 and CCG rate, da/dt as a function of an appropriate fracture mechanics related parameter generally provides results that are independent of specimen size and planar geometry for the same stress state at the crack tip for the range of geometries and sizes presented in this document (see Annex A1). Thus, the appropriate correlation will enable exchange and comparison of data obtained from a variety of specimen configurations and loading conditions. Moreover, this feature enables creep crack growth data to be utilized in the design and evaluation of engineering structures operated at elevated temperatures where creep deformation is a concern. The concept of similitude is assumed, implying that cracks of differing sizes subjected to the same nominal C*(t), Ct, or K will advance by equal increments of crack extension per unit time, provided the conditions for the validity for the specific crack growth rate relating parameter are met. See 11.7 for details.  
6.2.2 The effects of crack tip constraint arising from variations in specimen size, geometry and material ductility can influence t0.2 and da/dt. For example, crack growth rates at the same value of C*(t), Ct in creep-ductile materials generally increases with increasing thickness. It is therefore necessary to keep the component dimensions in mind when selecti...
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ASTM E1221-23(Test Method)
Standard Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic Steels

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5.1 In structures containing gradients in either toughness or stress, a crack may initiate in a region of either low toughness or high stress, or both, and arrest in another region of either higher toughness or lower stress, or both. The value of the stress intensity factor during the short time interval in which a fast-running crack arrests is a measure of the ability of the material to arrest such a crack. Values of the stress intensity factor of this kind, which are determined using dynamic methods of analysis, provide a value for the crack-arrest fracture toughness which will be termed KA  in this discussion. Static methods of analysis, which are much less complex, can often be used to determine K at a short time (1 to 2 ms) after crack arrest. The estimate of the crack-arrest fracture toughness obtained in this fashion is termed K a. When macroscopic dynamic effects are relatively small, the difference between KA  and Ka  is also small (1-4). For cracks propagating under conditions of crack-front plane-strain, in situations where the dynamic effects are also known to be small, KIa  determinations using laboratory-sized specimens have been used successfully to estimate whether, and at what point, a crack will arrest in a structure (5, 6). Depending upon component design, loading compliance, and the crack jump length, a dynamic analysis of a fast-running crack propagation event may be necessary in order to predict whether crack arrest will occur and the arrest position. In such cases, values of K Ia  determined by this test method can be used to identify those values of K below which the crack speed is zero. More details on the use of dynamic analyses can be found in Ref (4).  
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Standard Test Method for Measurement of Fracture Toughness

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.  
5.1.1 These fracture toughness values may serve as a basis for material comparison, selection, and quality assurance. Fracture toughness can be used to rank materials within a similar yield strength range.  
5.1.2 These fracture toughness values may serve as a basis for structural flaw tolerance assessment. Awareness of differences that may exist between laboratory test and field conditions is required to make proper flaw tolerance assessment.  
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.  
5.2.2 The J-R curve from bend-type specimens recommended by this test method (SE(B), C(T), and DC(T)) has been observed to be conservative with respect to results from tensile loading configurations.  
5.2.3 The values of δc, δu, Jc, and Ju  may be affected by specimen dimensions.
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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.
Note 1: Until this version, KIc could be evaluated using this test method as well as by using Test Method E399. To avoid duplication, the evaluation of KIc has been removed from this test method and the user is referred to Test Method E399.  
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.  
Note 2: Other standard methods for the determination of fracture toughness using the parameters K, J, and CTOD are contained in Test Methods E399, E1290, and E1921. This test method was developed to provide a common method for determining all applicable toughness parameters from a single test.  
1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
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4.1 Fatigue test results may be significantly influenced by the properties and history of the parent material, the operations performed during the preparation of the fatigue specimens, and the testing machine and test procedures used during the generation of the data. The presentation of fatigue test results should include citation of basic information on the material, specimens, and testing to increase the utility of the results and to reduce to a minimum the possibility of misinterpretation or improper application of those results.
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1.1 This practice covers the desirable and minimum information to be communicated between the originator and the user of data derived from constant-force amplitude axial, bending, or torsion fatigue tests of metallic materials tested in air and at room temperature.  
Note 1: Practice E466, although not directly referenced in the text, is considered important enough to be listed in this standard.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
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ASTM
ASTM E561-23(Test Method)
Standard Test Method for KR Curve Determination

SIGNIFICANCE AND USE
5.1 The KR curve characterizes the resistance to fracture of materials during slow, stable crack extension and results from the growth of the plastic zone ahead of the crack as it extends from a fatigue precrack or sharp notch. It provides a record of the toughness development as a crack is driven stably under increasing applied stress intensity factor K. For a given material, KR curves are dependent upon specimen thickness, temperature, and strain rate. The amount of valid KR data generated in the test depends on the specimen type, size, method of loading, and, to a lesser extent, testing machine characteristics.  
5.2 For an untested geometry, the KR curve can be matched with the applied-K curves (crack driving curves) to estimate the degree of stable crack extension and the conditions necessary to cause unstable crack propagation (2). In making this estimate, KR curves are regarded as being independent of initial crack size ao and the specimen configuration in which they are developed. For a given material, material thickness, and test temperature, KR curves appear to be a function of only the effective crack extension Δae (3).  
5.2.1 To predict crack behavior and instability in a component, a family of applied-K curves is generated by calculating  K as a function of crack size for the component using a series of force, displacement, or combined loading conditions. The KR curve may be superimposed on the family of applied-K curves as shown in Fig. 1, with the origin of the KR curve coinciding with the assumed initial crack size ao. The intersection of the applied-K curves with the KR curve shows the expected effective stable crack extension for each loading condition. The applied-K curve that develops tangency with the KR curve defines the critical loading condition that will cause the onset of unstable fracture under the loading conditions used to develop the applied-K curves.
FIG. 1 Schematic Representation of KR curve and Applied K Curves to Predict Insta...
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1.1 This test method covers the determination of the resistance to fracture of metallic materials under Mode I loading at static rates using either of the following notched and precracked specimens: the middle-cracked tension M(T) specimen or the compact tension C(T) specimen. A KR curve is a continuous record of toughness development (resistance to crack extension) in terms of KR plotted against crack extension in the specimen as a crack is driven under an increasing stress intensity factor, K. (1)2  
1.2 Materials that can be tested for KR curve development are not limited by strength, thickness, or toughness, so long as specimens are of sufficient size to remain predominantly elastic to the effective crack extension value of interest.  
1.3 Specimens of standard proportions are required, but size is variable, to be adjusted for yield strength and toughness of the materials.  
1.4 Only two of the many possible specimen types that could be used to develop KR curves are covered in this method.  
1.5 The test is applicable to conditions where a material exhibits slow, stable crack extension under increasing crack driving force, which may exist in relatively tough materials under plane stress crack tip conditions.  
1.6 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.7 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Reco...

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ASTM
ASTM E2789-10(2021)(Guide)
Standard Guide for Fretting Fatigue Testing

SIGNIFICANCE AND USE
4.1 Fretting fatigue tests are used to determine the effects of several fretting parameters on the fatigue lives of metallic materials. Some of these parameters include differing materials, relative displacement amplitudes, normal force at the fretting contact, alternating tangential force, the contact geometry, surface integrity parameters such as finish, and the environment. Comparative tests are used to determine the effectiveness of palliatives on the fatigue life of specimens with well-controlled boundary conditions so that the mechanics of the fretting fatigue test can be modeled. Generally, it is useful to compare the fretting fatigue response to plain fatigue to obtain knockdown or reduction factors from fretting fatigue. The results may be used as a guide in selecting material combinations, design stress levels, lubricants, and coatings to alleviate or eliminate fretting fatigue concerns in new or existing designs. However, due to the synergisms of fatigue, wear, and corrosion on the fretting fatigue parameters, extreme care should be exercised in the judgment to determine if the test conditions meet the design or system conditions.  
4.2 For data to be comparable, reproducible, and correlated amongst laboratories and relevant to mimic fretting in an application, all parameters critical to the fretting fatigue life of the material in question will need to be replicated. Because alterations in environment, metallurgical properties, fretting loading (controlled forces and displacements), compliance of the test system, etc. can affect the response, no general guidelines exist to quantitatively ascertain what the effect will be on the specimen fretting fatigue life if a single parameter is varied. To assure test results can be correlated and reproduced, all material variables, testing information, physical procedures, and analytical procedures should be reported in a manner that is consistent with good current test practices.  
4.3 Because of the wear phenome...
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1.1 This guide defines terminology and covers general requirements for conducting fretting fatigue tests and reporting the results. It describes the general types of fretting fatigue tests and provides some suggestions on developing and conducting fretting fatigue test programs.  
1.2 Fretting fatigue tests are designed to determine the effects of mechanical and environmental parameters on the fretting fatigue behavior of metallic materials. This guide is not intended to establish preference of one apparatus or specimen design over others, but will establish guidelines for adherence in the design, calibration, and use of fretting fatigue apparatus and recommend the means to collect, record, and reporting of the data.  
1.3 The number of cycles to form a fretting fatigue crack is dependent on both the material of the fatigue specimen and fretting pad, the geometry of contact between the two, and the method by which the loading and displacement are imposed. Similar to wear behavior of materials, it is important to consider fretting fatigue as a system response, instead of a material response. Because of this dependency on the configuration of the system, quantifiable comparisons of various material combinations should be based on tests using similar fretting fatigue configurations and material couples.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM E466-21(Practice)
Standard Practice for Conducting Force Controlled Constant Amplitude Axial Fatigue Tests of Metallic Materials

SIGNIFICANCE AND USE
4.1 The axial force fatigue test is used to determine the effect of variations in material, geometry, surface condition, stress, and so forth, on the fatigue resistance of metallic materials subjected to direct stress for relatively large numbers of cycles. The results may also be used as a guide for the selection of metallic materials for service under conditions of repeated direct stress.  
4.2 In order to verify that such basic fatigue data generated using this practice is comparable, reproducible, and correlated among laboratories, it may be advantageous to conduct a round-robin-type test program from a statistician's point of view. To do so would require the control or balance of what are often deemed nuisance variables; for example, hardness, cleanliness, grain size, composition, directionality, surface residual stress, surface finish, and so forth. Thus, when embarking on a program of this nature it is essential to define and maintain consistency a priori, as many variables as reasonably possible, with as much economy as prudent. All material variables, testing information, and procedures used should be reported so that correlation and reproducibility of results may be attempted in a fashion that is considered reasonably good current test practice.  
4.3 The results of the axial force fatigue test are suitable for application to design only when the specimen test conditions realistically simulate service conditions or some methodology of accounting for service conditions is available and clearly defined.
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1.1 This practice covers the procedure for the performance of axial force controlled fatigue tests to obtain the fatigue strength of metallic materials in the fatigue regime where the strains are predominately elastic, both upon initial loading and throughout the test. This practice is limited to the fatigue testing of axial unnotched and notched specimens subjected to a constant amplitude, periodic forcing function in air at room temperature.  
1.2 The use of this test method is limited to specimens and does not cover testing of full-scale components, structures, or consumer products.  
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.4 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.
Note 1: The following documents, although not directly referenced in the text, are considered important enough to be listed in this practice:
E739 Practice for Statistical Analysis of Linear or Linearized Stress-Life (S-N) and Strain-Life (ε-N) Fatigue Data
STP 566 Handbook of Fatigue Testing2
STP 588 Manual on Statistical Planning and Analysis for Fatigue Experiments3
STP 731 Tables for Estimating Median Fatigue Limits4  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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