ASTM C554-93(1999)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:C554–93 (Reapproved 1999)
Standard Test Method for
Crazing Resistance of Fired Glazed Ceramic Whitewares by
a Thermal Shock Method
This standard is issued under the fixed designation C 554; 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 thermal stresses in service. Hence, an important use criterion
for a glazed whiteware is adequate resistance to repeated
1.1 This test method covers the determination of the resis-
abrupt thermal changes. In most cases, the result of inadequate
tance to crazing of fired, glazed, ceramic whitewares when
resistance to thermal shock is the appearance of a craze pattern
stresses residual after glost firing may cause a tendency to
in the glaze. This craze pattern is visible by inspection with
craze, such stresses being induced by factors other than
oblique lighting and application of a suitable ink or dye.
moisture expansion.
3.2 This test method is applicable to vitreous whitewares
1.2 This test is not intended to induce moisture expansion,
that have negligible crazing as a result of moisture expansion.
which fact should be kept in mind if the materials to be
For nonvitreous and semivitreous bodies, refer to Test Method
evaluated may exhibit moisture expansion.
C 424.
NOTE 1—Test Method C 424 covers a method for determining resis-
tance to crazing induced by moisture expansion. Its use is generally
4. Apparatus
confined to testing nonvitreous and semivitreous ceramic whitewares
4.1 Oven—An oven suitable to operate in the range 250 to
because these products may be subject to such expansion. For whitewares
450°F (121 to 232°C) while holding the required temperatures
with negligible moisture expansion (such as vitreous and impervious
within 65°F (63°C) and being capable of recovering tempera-
ware), the thermal shock method described herein is generally to be
preferred.
ture within 20 min after being loaded with the desired number
of specimen(s).
1.3 This standard does not purport to address all of the
4.2 Water Containers—Containers to hold water at 68 6
safety concerns, if any, associated with its use. It is the
5°F (20 6 3°C) before quenching; the capacity of the contain-
responsibility of the user of this standard to establish appro-
ers shall be large enough so that the water temperature does not
priate safety and health practices and determine the applica-
exceed 85°F (29°C) after quenching a single specimen. Two or
bility of regulatory limitations prior to use. For a specific
more specimens may be quenched simultaneously in a single
hazard statement, see Warning in 6.3.
container provided they do not overlap on the bottom of the
1.4 The values stated in inch-pound units are to be regarded
container and provided that the water temperature does not
as the standard. The values in parentheses are for information
exceed 85°F (29°C) after quenching. As a general rule, it will
only.
be found that 10 cm of water/g of ware, or 1 gal of water/lb
2. Referenced Documents
of ware will be adequate to keep the temperature within the
required limits. There shall be enough containers to quench all
2.1 ASTM Standards:
the specimens loaded in the oven. The containers shall be deep
C 424 Test Method for Crazing Resistance of Fired Glazed
enough so that at least ⁄2 in. (13 mm) of water will cover the
Whitewares by Autoclave Treatment
quenched specimen(s).
3. Significance and Use
5. Test Specimens
3.1 Unless there is a proper match between the expansions
5.1 The specimen(s) shall preferably be whole pieces of
of the glaze and the body, all glazed whitewares may contain
ware;cutorbrokenspecimen(s)shallbeusedonlywhenwhole
residual stresses from the firing that bonded the glaze to the
pieces are impractical or impossible to test. If the specimen(s)
body. In addition, whitewares are increasingly subjected to
are cut or broken from whole ware, they shall be selected so as
to be representative of the item to be tested. In cutting or
This test method is under the jurisdiction of ASTM Committee C-21 on
breaking specimen(s), cracks may be induced, therefore, bro-
Ceramic Whitewares and Related Products and is the direct responsibility of
ken or cut specimens shall be inspected for cracks by oblique
Subcommittee C21.03 on Test Methods for Whiteware Properties.
lighting and application of a suitable ink or dye before the test.
Current edition approved July 15, 1993. Published September 1993. Originally
published as C 554 – 64 T. Last previous edition C 554 – 93.
Annual Book of ASTM Standards, Vol 15.02.
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C554
Only broken or cut
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