ASTM E1921-22a
Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range

Standard No.

ASTM E1921-22a

Release Date

2022

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E1921-23

Latest

ASTM E1921-23b

Scope

1.1 This test method covers the determination of a reference temperature, T0, which characterizes the fracture toughness of ferritic steels that experience onset of cleavage cracking at elastic, or elastic-plastic KJc instabilities, or both. The specific types of ferritic steels (3.2.2) covered are those with yield strengths ranging from 275 to 825 MPa (40 to 120 ksi) and weld metals, after stress-relief annealing, that have 10 % or less strength mismatch relative to that of the base metal. 1.2 The specimens covered are fatigue precracked singleedge notched bend bars, SE(B), and standard or disk-shaped compact tension specimens, C(T) or DC(T). A range of specimen sizes with proportional dimensions is recommended. The dimension on which the proportionality is based is specimen thickness. 1.3 Median KJc values tend to vary with the specimen type at a given test temperature, presumably due to constraint differences among the allowable test specimens in 1.2. The degree of KJc variability among specimen types is analytically predicted to be a function of the material flow properties (1)2 and decreases with increasing strain hardening capacity for a given yield strength material. This KJc dependency ultimately leads to discrepancies in calculated T0 values as a function of specimen type for the same material. T0 values obtained from C(T) specimens are expected to be higher than T0 values obtained from SE(B) specimens. Best estimate comparisons of several materials indicate that the average difference between C(T) and SE(B)-derived T0 values is approximately 10°C (2). C(T) and SE(B) T0 differences up to 15 °C have also been recorded (3). However, comparisons of individual, small datasets may not necessarily reveal this average trend. Datasets which contain both C(T) and SE(B) specimens may generate T0 results which fall between the T0 values calculated using solely C(T) or SE(B) specimens. It is therefore strongly recommended that the specimen type be reported along with the derived T0 value in all reporting, analysis, and discussion of results. This recommended reporting is in addition to the requirements in 11.1.1. 1.4 Requirements are set on specimen size and the number of replicate tests that are needed to establish acceptable characterization of KJc data populations. 1.5 T0 is dependent on loading rate. T0 is evaluated for a quasi-static loading rate range with 0.1< dK/dt < 2 MPa√m/s. Slowly loaded specimens (dK/dt < 0.1 MPa√m) can be analyzed if environmental effects are known to be negligible. Provision is also made for higher loading rates (dK/dt > 2 MPa√m/s) in Annex A1. Note that this threshold loading rate for application of Annex A1 is a much lower threshold than is required in other fracture toughness test methods such as E399 and E1820. 1.6 The statistical effects of specimen size on KJc in the transition range are treated using the weakest-link theory (4) applied to a three-parameter Weibull distribution of fracture toughness values. A limit on KJc values, relative to the specimen size, is specified to ensure high constraint conditions along the crack front at fracture. For some materials, particularly those with low strain hardening, this limit may not be sufficient to ensure that a single-parameter (KJc) adequately describes the crack-front deformation state (5). 1.7 Statistical methods are employed to predict the transition toughness curve and specified tolerance bounds for 1T specimens of the material tested. The standard deviation of the data distribution is a function of Weibull slope and median KJc. The procedure for applying this information to the establishment of transition temperature shift determinations and the establishment of tolerance limits is prescribed. 1.8 The procedures described in this test method assume that the data set represents a macroscopically homogeneous material, such that the test material has uniform tensile and toughness properties. Application of this test method to an inhomogeneous material will result in an inaccurate estimate of the transition reference value T0 and nonconservative confidence bounds. For example, multi-pass weldments can create heat-affected and brittle zones with localized properties that are 1 This test method is under the jurisdiction of ASTM Committee E08 on Fatigue and Fracture and is the direct responsibility of E08.07 on Fracture Mechanics. Current edition approved Nov. 1, 2022. Published December 2022. Originally approved in 1997. Last previous edition approved in 2022 as E1921 – 22. DOI: 10.1520/E1921-22A. 2 The boldface numbers in parentheses refer to the list of references at the end of this standard. Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States 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. 1 quite different from either the bulk or weld materials. Thicksection steels also often exhibit some variation in properties near the surfaces. Metallography and initial screening may be necessary to verify the applicability of these and similarly graded materials. Section 10.6 provides a screening criterion to assess whether the data set may not be representative of a macroscopically homogeneous material, and therefore, may not be amenable to the statistical analysis procedures employed in this test method. If the data set fails the screening criterion in 10.6, the homogeneity of the material and its fracture toughness can be more accurately assessed using the analysis methods described in Appendix X5. 1.9 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. 1.10 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.

ASTM E1921-22a Referenced Document

• ASTM E111 Standard Test Method for Young''s Modulus, Tangent Modulus, and Chord Modulus
• ASTM E177 Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E1820 Standard Test Method for Measurement of Fracture Toughness
• ASTM E1823 Standard Terminology Relating to Fatigue and Fracture Testing
• ASTM E208 Standard Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels
• ASTM E23 Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
• ASTM E399 Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials
• ASTM E4 Standard Practices for Force Verification of Testing Machines
• ASTM E436 Standard Test Method for Drop-Weight Tear Tests of Ferritic Steels
• ASTM E561 Standard Practice for R-Curve Determination
• ASTM E691 Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• ASTM E74 Standard Practices for Calibration and Verification for Force-Measuring Instruments
• ASTM E8/E8M Standard Test Methods for Tension Testing of Metallic Materials*， 2024-01-01 Update

ASTM E1921-22a history

• 2023 ASTM E1921-23b Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2023 ASTM E1921-23a Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2023 ASTM E1921-23 Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2022 ASTM E1921-22a Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2022 ASTM E1921-22 Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2021 ASTM E1921-21a Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range
• 2021 ASTM E1921-21 Standard Test Method for Determination of Reference Temperature,
• 2020 ASTM E1921-20 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2019 ASTM E1921-19be1 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2019 ASTM E1921-19b Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2019 ASTM E1921-19a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2019 ASTM E1921-19 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2018 ASTM E1921-18a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2018 ASTM E1921-18 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2017 ASTM E1921-17a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2017 ASTM E1921-17 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2016 ASTM E1921-16 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2015 ASTM E1921-15ae1 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2015 ASTM E1921-15a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2015 ASTM E1921-15 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2014 ASTM E1921-14a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2014 ASTM E1921-14 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2013 ASTM E1921-13a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2013 ASTM E1921-13 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2012 ASTM E1921-12a Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2012 ASTM E1921-12 Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range
• 2011 ASTM E1921-11a Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2011 ASTM E1921-11 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2010 ASTM E1921-10e1 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2010 ASTM E1921-10 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09ce2 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09ce1 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09c Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09b Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09a Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2009 ASTM E1921-09 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2008 ASTM E1921-08ae1 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2008 ASTM E1921-08a Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2008 ASTM E1921-08 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2007 ASTM E1921-07 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 2005 ASTM E1921-05 Standard Test Method for Determination of Reference Temperature, T_o'', for Ferritic Steels in the Transition Range
• 2003 ASTM E1921-03 Standard Test Method for Determination of Reference Temperature, T_o'', for Ferritic Steels in the Transition Range
• 2002 ASTM E1921-02 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• 1997 ASTM E1921-97 Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range