ASTM E1921-02

Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range

SCOPE
1.1 This test method covers the determination of a reference temperature, To, 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 (3.2.1) 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 single-edge 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 Requirements are set on specimen size and the number of replicate tests that are needed to establish acceptable characterization of KJc data populations.
1.4 The statistical effects of specimen size on KJc in the transition range are treated using weakest-link theory (1) 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 (2).
1.5 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.
1.6 The fracture toughness evaluation of nonuniform material is not amenable to the statistical analysis methods employed in this standard. Materials must have macroscopically uniform tensile and toughness properties. For example, multipass weldments can create heat-affected and brittle zones with localized properties that are quite different from either the bulk material or weld. Thick section steel also often exhibits some variation in properties near the surfaces. Metallography and initial screening may be necessary to verify the applicability of these and similarly graded materials. Data falling outside the 2 % or 98 % tolerance bounds may be indicative of a nonuniform material (see 9.3).
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Mar-2002
• ICS: 77.040.10 - Mechanical testing of metals
• Technical Committee: E08 - Fatigue and Fracture
• Drafting Committee: E08.07 - Fracture Mechanics

Relations

• Replaces: ASTM E1921-97 - Standard Test Method for Determination of Reference Temperature, T_o, for Ferritic Steels in the Transition Range
• Effective Date: 10-Mar-2002
• Replaced By: ASTM E1921-03 - Standard Test Method for Determination of Reference Temperature, <i>T_o'</i>, for Ferritic Steels in the Transition Range
• Effective Date: 01-Nov-2003
• Referred By: ASTM E1820-23b - Standard Test Method for Measurement of Fracture Toughness
• Effective Date: 10-Mar-2002
• Referred By: ASTM E399-23 - Standard Test Method for Linear-Elastic Plane-Strain Fracture Toughness of Metallic Materials
• Effective Date: 10-Mar-2002
• Referred By: ASTM E1253-21 - Standard Guide for Reconstitution of Charpy-Sized Specimens
• Effective Date: 10-Mar-2002
• Referred By: ASTM E2899-19e1 - Standard Test Method for Measurement of Initiation Toughness in Surface Cracks Under Tension and Bending
• Effective Date: 10-Mar-2002
• Referred By: ASTM E185-21 - Standard Practice for Design of Surveillance Programs for Light-Water Moderated Nuclear Power Reactor Vessels
• Effective Date: 10-Mar-2002
• Referred By: ASTM E509/E509M-21 - Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels
• Effective Date: 10-Mar-2002
• Referred By: ASTM E1823-23 - Standard Terminology Relating to Fatigue and Fracture Testing
• Effective Date: 10-Mar-2002
• Referred By: ASTM E636-20 - Standard Guide for Conducting Supplemental Surveillance Tests for Nuclear Power Reactor Vessels
• Effective Date: 10-Mar-2002
• Referred By: ASTM E2215-19 - Standard Practice for Evaluation of Surveillance Capsules from Light-Water Moderated Nuclear Power Reactor Vessels
• Effective Date: 10-Mar-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1921 – 02
Standard Test Method for
Determination of Reference Temperature, T , for Ferritic
o
1
Steels in the Transition Range
This standard is issued under the fixed designation E 1921; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope ployed in this standard. Materials must have macroscopically
uniform tensile and toughness properties. For example, multi-
1.1 This test method covers the determination of a reference
pass weldments can create heat-affected and brittle zones with
temperature, T , which characterizes the fracture toughness of
o
localized properties that are quite different from either the bulk
ferritic steels that experience onset of cleavage cracking at
material or weld. Thick section steel also often exhibits some
elastic, or elastic-plastic K instabilities, or both. The specific
Jc
variation in properties near the surfaces. Metallography and
types of ferritic steels (3.2.1) covered are those with yield
initial screening may be necessary to verify the applicability of
strengths ranging from 275 to 825 MPa (40 to 120 ksi) and
these and similarly graded materials. Paticular notice should be
weld metals, after stress-relief annealing, that have 10 % or
given to the 2% and 98% tolerance bounds on K presented in
less strength mismatch relative to that of the base metal. Jc
9.3. Data falling outside these bounds may indicate nonuniform
1.2 The specimens covered are fatigue precracked single-
material properties.
edge notched bend bars, SE(B), and standard or disk-shaped
1.7 This standard does not purport to address all of the
compact tension specimens, C(T) or DC(T). A range of
safety concerns, if any, associated with its use. It is the
specimen sizes with proportional dimensions is recommended.
responsibility of the user of this standard to establish appro-
The dimension on which the proportionality is based is
priate safety and health practices and determine the applica-
specimen thickness.
bility of regulatory limitations prior to use.
1.3 Requirements are set on specimen size and the number
of replicate tests that are needed to establish acceptable
2. Referenced Documents
characterization of K data populations.
Jc
2.1 ASTM Standards:
1.4 The statistical effects of specimen size on K in the
Jc
3
2 E 4 Practices for Force Verification of Testing Machines
transition range are treated using weakest-link theory (1)
E 8M Test Methods for Tension Testing of Metallic Mate-
applied to a three-parameter Weibull distribution of fracture
3
rials (Metric)
toughness values. A limit on K values, relative to the
Jc
E 23 Test Methods for Notched Bar Impact Testing of
specimen size, is specified to ensure high constraint conditions
3
Metallic Materials
along the crack front at fracture. For some materials, particu-
E 74 Practice for Calibration of Force Measuring Instru-
larly those with low strain hardening, this limit may not be
ments for Verifying the Force Indication of Testing Ma-
sufficient to ensure that a single-parameter (K ) adequately
Jc
3
chines
describes the crack-front deformation state (2).
E 208 Test Method for Conducting Drop-Weight Test to
1.5 Statistical methods are employed to predict the transi-
Determine Nil-Ductility Transition Temperature of Ferritic
tion toughness curve and specified tolerance bounds for 1T
3
Steels
specimens of the material tested. The standard deviation of the
E 399 Test Method for Plane-Strain Fracture Toughness of
data distribution is a function of Weibull slope and median K .
Jc
3
Metallic Materials
The procedure for applying this information to the establish-
E 436 Test Method for Drop-Weight Tear Tests of Ferritic
ment of transition temperature shift determinations and the
3
Steels
establishment of tolerance limits is prescribed.
3
E 561 Practice for R-Curve Determination
1.6 The fracture toughness evaluation of nonuniform mate-
E 812 Test Method for Crack Strength of Slow-Bend, Pre-
rial is not amenable to the statistical analysis methods em-
cracked Charpy Specimens of High-Strength Metallic
3
Materials
1
This test method is under the jurisdiction of ASTM Committee E08 on Fatigue E 1820 Test Method for Measurement of Fracture Tough-
3
and Fracture and is the direct responsibility of E08.08 on Elastic-Plastic Fracture
ness
Mechanics Technology.
Current edition approved March. 10, 2002. Published June 2002. Originally
e1
published as E 1921 – 97. Last previous edition E 1921 – 97 .
2
The boldface numbers in parentheses refer to the list of references at the end of
3
this standard. Annual Book of ASTM Standards, Vol 03.01.
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