ASTM C368-88(2006)
(Test Method)Standard Test Method for Impact Resistance of Ceramic Tableware
Standard Test Method for Impact Resistance of Ceramic Tableware
SIGNIFICANCE AND USE
The purpose of this test method is to predict product resistance to impact breakage in service.
SCOPE
1.1 This test method covers the following tests:
1.1.1 Impact tests at the center of both flatware and hollow ware and at the rim of hollow ware, and
1.1.2 Chipping tests at the rim of flatware. Specimens may be either glazed or unglazed. Note 1The impact test at the center of the specimen is used to determine: (1) the magnitude of a blow that will produce initial fracture, and (2) the amount of energy necessary to produce complete failure. In the first case, the initial fracture shows on the side of the piece opposite from that being struck and appears to be a function of the square of the thickness and of the inherent brittleness of the body or body-glaze combination; it is relatively independent of the size or design of the specimen. The second factor is more dependent upon design and often is subject to wide variation within a given group of pieces.
Note 2
The impact test at the rim of hollow ware is similar to a chipping test, and the type of failure that is obtained is useful in evaluating the effect of the shape of the object.
Note 3
In addition to the inherent strength of the body, chipping test results are greatly affected by contour of rim and to a lesser extent by thickness of rim, inclination of leaf, and fit of glaze.
1.2 The values stated in inch-pound units are to be regarded as the standard. The SI (metric) units given in parentheses are for information purposes only.
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.
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Designation:C368–88(Reapproved 2006)
Standard Test Method for
Impact Resistance of Ceramic Tableware
This standard is issued under the fixed designation C368; 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 3. Significance and Use
1.1 This test method covers the following tests: 3.1 The purpose of this test method is to predict product
1.1.1 Impact tests at the center of both flatware and hollow resistance to impact breakage in service.
ware and at the rim of hollow ware, and
4. Apparatus
1.1.2 Chipping tests at the rim of flatware. Specimens may
be either glazed or unglazed. 4.1 Impact Tester, Pendulum Type—The impact test appa-
ratus (Figs. 1 and 2) shall consist of a device having the
NOTE 1—The impact test at the center of the specimen is used to
following essential features:
determine: (1) the magnitude of a blow that will produce initial fracture,
4.1.1 Asteel tup of specified size and of hardness Rockwell
and (2) the amount of energy necessary to produce complete failure. In the
C55,
first case, the initial fracture shows on the side of the piece opposite from
that being struck and appears to be a function of the square of the 4.1.2 Support of a tup by a V-suspension,
thickness and of the inherent brittleness of the body or body-glaze
4.1.3 Provision for a means of release from fixed heights so
combination; it is relatively independent of the size or design of the
astogivereproducibleresults,independentoftheoperator,and
specimen. The second factor is more dependent upon design and often is
4.1.4 Provision for holding the test specimen in place by
subject to wide variation within a given group of pieces.
spring clamps against rigid metal supports.
NOTE 2—The impact test at the rim of hollow ware is similar to a
4.2 Micrometer—For measuring thickness of test speci-
chipping test, and the type of failure that is obtained is useful in evaluating
mens, a micrometer caliper that can be read to 0.001 in. (0.03
the effect of the shape of the object.
NOTE 3—In addition to the inherent strength of the body, chipping test
mm) shall be used.
results are greatly affected by contour of rim and to a lesser extent by
thickness of rim, inclination of leaf, and fit of glaze. 5. Test Specimens
1.2 The values stated in inch-pound units are to be regarded 5.1 Specimens shall be selected so as to be representative of
as the standard. The SI (metric) units given in parentheses are thelotbeingsampled.Ingeneral,impacttestsshallbebasedon
for information purposes only. a minimum of ten specimens and chipping tests on at least five
1.3 This standard does not purport to address all of the specimens. Specimens shall be inspected for soundness and
safety concerns, if any, associated with its use. It is the obvious physical defects before testing.
responsibility of the user of this standard to establish appro-
6. Procedure for Impact Testing of Flatware
priate safety and health practices and determine the applica-
6.1 Mount the cylindrical tube shown in Fig. 2 (Note 4)on
bility of regulatory limitations prior to use.
the backstop, C, Fig. 1, and set at a height such that the three
2. Referenced Documents
ball bearings mounted in the end of the cylindrical tube are in
2.1 ASTM Adjuncts: contact and symmetrical with the central portion of the
ADJC0368 Machine for Testing Chinaware specimen, which shall be stood on edge on the base plate. The
specimen may be tested with either the face or the back toward
the hammer; in general, a lower failure value is obtained when
This test method is under the jurisdiction ofASTM Committee C21 on Ceramic
the face is struck. Adjust the backstop so that the spherical
Whitewares and Related Products and is the direct responsibility of Subcommittee
surface of the tup, D, just touches the surface of the specimen
C21.03 on Methods of Whiteware Properties.
when the tup is hanging free (vertically). Tighten the two wing
Current edition approved Feb. 15, 2006. Published February 2006. Originally
approved in 1955. Last previous edition approved in 1999 as C368 – 88 (1999). nuts at the base of the backstop.
DOI: 10.1520/C0368-88R06.
NOTE 4—In this portion of the test, the cylindrical tube replaces the
Detailed working drawings of the apparatus are available from ASTM
Headquarters. Request Adjunct No. ADJC0368. angle clamp, E, shown in position on the backstop, C,in Fig. 1.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C368–88 (2006)
FIG. 1 Impact Test Apparatus
sleeve and of the clamp coincide. Adjust the clamps on the
vertical posts to grip the specimen at the same height that the
pendulum will strike it; that is, halfway up.Adjust the arms so
that the rubber-covered surface at right angles to its rod will
contact the rim of the sample; remove the cotter keys to permit
the positioning arms to hold the specimen against the cylindri-
FIG. 2 Tube to Support Flatware Specimen
cal tube. Adjust the pendulum support bar, B, and lock it in
6.2 Adjust the positioning arms,F, held in retracted position position by means of the handwheels, A, so that the tup strikes
by means of their cotter keys so that the forward edges of the the center of the specimen.
C368–88 (2006)
6.3 With the preliminary adjustments completed, subject the 9.2.1 Repeatedly strike rolled-edge specimens on the edge
specimen to a schedule of impacts starting at 0.02 ft·lbf (0.027 with the cylindrical end of the hammer with blows of increas-
J) and increasing in increments of 0.01 ft·lbf (0.014 J) until ing force until failure occurs, beginning with an initial blow of
initial fracture, and in increments of 0.02 ft·lbf thereafter to 0.10
...
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