1、Designation:C36888(Reapproved 2016)Standard Test Method forImpact Resistance of Ceramic Tableware1This standard is issued under the fixed designation C368;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A nu
2、mber in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the following tests:1.1.1 Impact tests at the center of both flatware and hollowware and at the rim of hollow ware,an
3、d1.1.2 Chipping tests at the rim of flatware.Specimens maybe either glazed or unglazed.NOTE1The impact test at the center of the specimen is used todetermine:(1)the magnitude of a blow that will produce initial fracture,and(2)the amount of energy necessary to produce complete failure.In thefirst cas
4、e,the initial fracture shows on the side of the piece opposite fromthat being struck and appears to be a function of the square of thethickness and of the inherent brittleness of the body or body-glazecombination;it is relatively independent of the size or design of thespecimen.The second factor is
5、more dependent upon design and often issubject to wide variation within a given group of pieces.NOTE2The impact test at the rim of hollow ware is similar to achipping test,and the type of failure that is obtained is useful in evaluatingthe effect of the shape of the object.NOTE3In addition to the in
6、herent strength of the body,chipping testresults are greatly affected by contour of rim and to a lesser extent bythickness of rim,inclination of leaf,and fit of glaze.1.2 The values stated in inch-pound units are to be regardedas the standard.The SI(metric)units given in parentheses arefor informati
7、on purposes only.1.3This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.
8、Referenced Documents2.1 ASTM Adjuncts:2ADJC0368 Machine for Testing Chinaware3.Significance and Use3.1 The purpose of this test method is to predict productresistance to impact breakage in service.4.Apparatus4.1 Impact Tester,Pendulum TypeThe impact test appara-tus(Figs.1 and 2)2shall consist of a d
9、evice having thefollowing essential features:4.1.1 A steel tup of specified size and of hardness RockwellC55,4.1.2 Support of a tup by a V-suspension,4.1.3 Provision for a means of release from fixed heights soas to give reproducible results,independent of the operator,and4.1.4 Provision for holding
10、 the test specimen in place byspring clamps against rigid metal supports.4.2 MicrometerFormeasuringthicknessoftestspecimens,a micrometer caliper that can be read to 0.001 in.(0.03 mm)shall be used.5.Test Specimens5.1 Specimens shall be selected so as to be representative ofthe lot being sampled.In g
11、eneral,impact tests shall be based ona minimum of ten specimens and chipping tests on at least fivespecimens.Specimens shall be inspected for soundness andobvious physical defects before testing.6.Procedure for Impact Testing of Flatware6.1 Mount the cylindrical tube shown in Fig.2(Note 4)onthe back
12、stop,C,Fig.1,and set at a height such that the threeball bearings mounted in the end of the cylindrical tube are incontact and symmetrical with the central portion of thespecimen,which shall be stood on edge on the base plate.Thespecimen may be tested with either the face or the back towardthe hamme
13、r;in general,a lower failure value is obtained whenthe face is struck.Adjust the backstop so that the sphericalsurface of the tup,D,just touches the surface of the specimenwhen the tup is hanging free(vertically).Tighten the two wingnuts at the base of the backstop.NOTE4In this portion of the test,t
14、he cylindrical tube replaces theangle clamp,E,shown in position on the backstop,C,in Fig.1.6.2 Adjust the positioning arms,F,held in retracted positionby means of their cotter keys so that the forward edges of thesleeve and of the clamp coincide.Adjust the clamps on thevertical posts to grip the spe
15、cimen at the same height that thependulum will strike it;that is,halfway up.Adjust the arms sothat the rubber-covered surface at right angles to its rod willcontact the rim of the sample;remove the cotter keys to permit1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitew
16、ares and Related Products and is the direct responsibility of SubcommitteeC21.03 on Methods for Whitewares and Environmental Concerns.Current edition approved July 1,2016.Published July 2016.Originally approvedin 1955.Last previous edition approved in 2011 as C368 88(2011).DOI:10.1520/C0368-88R16.2Detailed working drawings of the apparatus are available from ASTMHeadquarters.Request Adjunct No.ADJC0368.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959
