ASTM C674-13(2023)
(Test Method)Standard Test Methods for Flexural Properties of Ceramic Whiteware Materials
Standard Test Methods for Flexural Properties of Ceramic Whiteware Materials
SIGNIFICANCE AND USE
3.1 These test methods provide a means for determining the modulus of rupture and the modulus of elasticity, which may be required in product specifications.
SCOPE
1.1 These test methods cover determination of the modulus of rupture and the modulus of elasticity of fired ceramic whitewares bodies, formed by any fabrication method, and are applicable to both glazed and unglazed test specimens.
1.2 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.
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.
1.4 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.
General Information
Standards Content (Sample)
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.
Designation: C674 − 13 (Reapproved 2023)
Standard Test Methods for
Flexural Properties of Ceramic Whiteware Materials
This standard is issued under the fixed designation C674; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 4.1.1 For all specimens the loading rate should be such that
the specimen should fail in approximately 1 min. Table 1 lists
1.1 These test methods cover determination of the modulus
loading rates that shall be used for each size specimen. For
of rupture and the modulus of elasticity of fired ceramic
strengths of specimens intermediate of those specified, inter-
whitewares bodies, formed by any fabrication method, and are
polation can be used to obtain the equivalent loading rate.
applicable to both glazed and unglazed test specimens.
4.1.2 For the prescribed rectangular specimens the loading
1.2 The values stated in inch-pound units are to be regarded
rate shall be 1000 lb 6 150 lb (454 kg 6 68 kg)/min.
as the standard. The metric equivalents of inch-pound units
4.2 Bearing Edges—For the support of the test specimen,
may be approximate.
two steel (or high-strength ceramic) knife edges rounded to a
1.3 This standard does not purport to address all of the
radius of 0.125 in. (3.18 mm) shall be provided. The load shall
safety concerns, if any, associated with its use. It is the
be applied by means of a third steel knife edge rounded to a
responsibility of the user of this standard to establish appro-
radius of 0.125 in. When testing rectangular specimens, the
priate safety, health, and environmental practices and deter-
supporting members for the bearing edges shall be constructed
mine the applicability of regulatory limitations prior to use.
to provide a means for alignment of the bearing surfaces with
1.4 This international standard was developed in accor-
the surfaces of the test specimen (it being possible that the
dance with internationally recognized principles on standard-
rectangular specimen may be wedge-shaped or twisted). The
ization established in the Decision on Principles for the
apparatus shown in Figs. 1 and 2 are suggested as suitable
Development of International Standards, Guides and Recom-
devices for ensuring proper spacing and alignment of the
mendations issued by the World Trade Organization Technical
bearing edges for rectangular test specimens.
Barriers to Trade (TBT) Committee.
5. Test Specimens
2. Summary of Test Methods
5.1 Preparation of Specimens—Form, fire, and finish the
2.1 The specimens, either cylindrical, or rectangular, are
specimens by the appropriate methods, following practices
supported on knife edges over a suitable span and a direct load
used in actual production.
is applied at the midpoint between the supports at a uniform
5.2 Dimensions—The specimens shall be approximately
rate until breakage occurs. The modulus of elasticity may be
1.125 in. (28.6 mm), 0.750 in. (19.2 mm), 0.500 in. (12.7 mm),
determined by halting the applied load at definite intervals and
or 0.250 in. (6.4 mm) in diameter, whichever diameter is most
measuring the deflection of the specimen at the midpoint to the
comparable to that of the finished product. The length shall be
nearest 0.001 in. (0.025 mm).
6 in. 6 0.50 in. (153 mm 6 12.7 mm) to permit an overhang
3. Significance and Use
of at least 0.25 in. (6.4 mm) at each end when mounted on the
3.1 These test methods provide a means for determining the
supports. Note that the 0.25 in. specimens may be 3.75 in. 6
modulus of rupture and the modulus of elasticity, which may
0.25 in. (95 mm 6 7 mm) long.
be required in product specifications.
5.2.1 The dry-pressed specimens shall be rectangular bars
approximately 1 in. (25.4 mm) by 0.50 in. (12.7 mm) in cross
4. Apparatus
section and at least 4.50 in. (114 mm) in length to permit an
4.1 Testing Machine—Any suitable testing machine may be
overhang of at least 0.25 in. at each end when mounted on the
used, provided uniform rates of direct loading can be main-
supports.
tained.
5.3 Handling—Observe all due precautions in the forming,
drying, and firing to produce straight test specimens of uniform
These test methods are under the jurisdiction of ASTM Committee C21 on
cross section.
Ceramic Whitewares and Related Productsand are the direct responsibility of
Subcommittee C21.03 on Methods for Whitewares and Environmental Concerns.
5.4 Storage—Cool test specimens taken warm from the kiln
Current edition approved March 1, 2023. Published March 2023. Originally
in a desiccator. If the testing must be delayed, store the bars in
approved in 1971. Last previous edition approved in 2018 as C674 – 13 (2018).
DOI: 10.1520/C0674-13R23. the desiccator, or in an electric oven at 110 °C, and then cool
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C674 − 13 (2023)
TABLE 1 Loading Rates for Specimens
Nominal MOR, ksi (MPa)
Span, in. (mm) 10 (69) 30 (207) 50 (345)
Specimen Size, in. (mm)
Loading Rate, lb/min (kg/s)
1.125 (28.6) diameter 5 (127) 1100 (8.32) 3400 (25.70) 5600 (42.34)
0.750 (19.2) “ 5 (127) 300 (2.27) 1000 (7.56) 1700 (12.85)
0.500 (12.7) “ 5 (127) 100 (0.76) 300 (2.27) 500 (3.76)
0.250 (6.4) “ 3 (76) 20 (0.15) 60 (0.45) 100 (0.76)
1 by 0.50 (25.4 by 12.7) 4 (102) 400 (3.02) 1250 (9.45) 2100 (15.88)
FIG. 1 Suggested Bearing Edge and Specimen Support
FIG. 2 Alternative Suggested Bearing Edge and Specimen Support
Sections 10 – 11 on the same type specimens used for the modulus of
in a desiccator before testing. When removing specimens from
rupture test.
a hot kiln, take care to avoid thermal shock which will lead to
erroneous results.
6.2 Place the cylindrical specimen on the bearing edges,
spaced 5 in. (127 mm) 6 2 % between centers, with the
MODULUS OF RUPTURE
specimen overhanging each end by at least 0.25 in. (6.4 mm).
6. Procedure Apply the load at a right angle to the specimen and midway
(62 %) between the supporting edges. Apply the load uni-
6.1 Test at least ten dry specimens at room temperature.
formly at the appropriate rate for the specimen size (see 4.1.1)
NOTE 1—The modulus of elasticity may be determined as described in
C674 − 13 (2023)
until failure occurs. Measure the diameter at four approxi- 9.1.1 Interlaboratory Test Data—An interlaboratory test
mately equidistant points at the break and take the average to was run in 1978 in which randomly drawn samples of five
the nearest 0.001 in. (0.0254 mm) for calculation purposes. materials were tested in each of four laboratories. One operator
Break the 0.25 in. diameter rods between 3 in. (76 mm) centers in each laboratory tested ten specimens of each material. The
and note this in the report. components of variance for flexural strength results expressed
6.2.1 Place the rectan
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