1、Designation: C 554 93 (Reapproved 2006)Standard Test Method forCrazing Resistance of Fired Glazed Ceramic Whitewares bya Thermal Shock Method1This standard is issued under the fixed designation C 554; the number immediately following the designation indicates the year oforiginal adoption or, in the
2、case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the resis-tance to crazing of fired, glaze
3、d, ceramic whitewares whenstresses residual after glost firing may cause a tendency tocraze, such stresses being induced by factors other thanmoisture expansion.1.2 This test is not intended to induce moisture expansion,which fact should be kept in mind if the materials to beevaluated may exhibit mo
4、isture expansion.NOTE 1Test Method C 424 covers a method for determining resis-tance to crazing induced by moisture expansion. Its use is generallyconfined to testing nonvitreous and semivitreous ceramic whitewaresbecause these products may be subject to such expansion. For whitewareswith negligible
5、 moisture expansion (such as vitreous and imperviousware), the thermal shock method described herein is generally to bepreferred.1.3 This 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
6、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For a specifichazard statement, see Warning in 6.3.1.4 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses are for informationonly.2. Refe
7、renced Documents2.1 ASTM Standards:2C 424 Test Method for Crazing Resistance of Fired GlazedWhitewares by Autoclave Treatment3. Significance and Use3.1 Unless there is a proper match between the expansionsof the glaze and the body, all glazed whitewares may containresidual stresses from the firing t
8、hat bonded the glaze to thebody. In addition, whitewares are increasingly subjected tothermal stresses in service. Hence, an important use criterionfor a glazed whiteware is adequate resistance to repeatedabrupt thermal changes. In most cases, the result of inadequateresistance to thermal shock is t
9、he appearance of a craze patternin the glaze. This craze pattern is visible by inspection withoblique lighting and application of a suitable ink or dye.3.2 This test method is applicable to vitreous whitewaresthat have negligible crazing as a result of moisture expansion.For nonvitreous and semivitr
10、eous bodies, refer to Test MethodC 424.4. Apparatus4.1 OvenAn oven suitable to operate in the range 250 to450F (121 to 232C) while holding the required temperatureswithin 65F (63C) and being capable of recovering tempera-ture within 20 min after being loaded with the desired numberof specimen(s).4.2
11、 Water ContainersContainers to hold water at 68 65F (20 6 3C) before quenching; the capacity of the contain-ers shall be large enough so that the water temperature does notexceed 85F (29C) after quenching a single specimen. Two ormore specimens may be quenched simultaneously in a singlecontainer pro
12、vided they do not overlap on the bottom of thecontainer and provided that the water temperature does notexceed 85F (29C) after quenching. As a general rule, it willbe found that 10 cm3of water/g of ware, or 1 gal of water/lbof ware will be adequate to keep the temperature within therequired limits.
13、There shall be enough containers to quench allthe specimens loaded in the oven. The containers shall be deepenough so that at least12 in. (13 mm) of water will cover thequenched specimen(s).5. Test Specimens5.1 The specimen(s) shall preferably be whole pieces ofware; cut or broken specimen(s) shall
14、be used only when wholepieces are impractical or impossible to test. If the specimen(s)are cut or broken from whole ware, they shall be selected so asto be representative of the item to be tested. In cutting orbreaking specimen(s), cracks may be induced, therefore, bro-ken or cut specimens shall be
15、inspected for cracks by obliquelighting and application of a suitable ink or dye before the test.1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Products and is the direct responsibility of SubcommitteeC21.03 on Methods for Whitewares and Environment
16、al Concerns.Current edition approved Feb. 15, 2006. Published Febraury 2006. Originallyapproved in 1964. Last previous edition approved in 1999 as C 554 93 (1999).2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
17、 of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.Only broken or cut specimen(s) free from cracks shall be used.The number of specime
18、ns shall not be less than five, whichnumber shall constitute a sample.6. Procedure6.1 Set the oven to 250F (121C). When the oven tempera-ture has reached equilibrium, place the specimen(s) in the ovenin a manner that will allow ample heat penetration of allspecimen(s). The specimen(s) should be plac
19、ed on edge in acustom metal rack that is made to meet the needs of the test. Acustom metal rack is one that will permit surrounding aircirculation so that the specimen(s) are separated to allow atleast12 in. of air space on all sides. Let the specimen(s) remainin the closed oven for not less than 45
20、 min. Ascertain byobservation for each heating that the oven has achieved the testtemperature within 20 min.6.2 Place a sufficient number of water containers near theoven.6.3 After the specimen(s) have been heated the requiredtime, transfer them all, as quickly as possible from the oven tothe quench
21、ing water. (Warning: Wear safety glasses whentransferring samples from the oven to the quenching water.)6.4 When the quenched specimen(s) have cooled to ap-proximately the temperature of the water, remove and drythem, and carefully examine the glazed surface for crazemarks. Use oblique lighting and
22、apply a suitable ink or dyesolution upon the glazed surface to aid in the detection ofcrazing. Consider only those failures that are visible to thenaked eye.6.5 Eliminate specimen(s) that exhibit crazing from furthertesting, but subject any undamaged specimen(s) to anotherheating and quenching cycle
23、.6.6 As long as the specimen(s) continue to resist crazing,heat and quench them repeatedly for three cycles at oventemperatures which increase by increments of 25F (13.9C)until a temperature of 450F (232C) is attained.6.7 In examining the specimen(s), take care to distinguishbetween body cracks and
24、craze marks. A few pieces ofunglazed bisque may be included in the test to enable thediscernment of body cracks caused by thermal shock. If theunglazed bisque is cracked by thermal shock, the glazedspecimen(s) may have cracked also without necessarily craz-ing. Experience and judgment are necessary
25、to distinguishbody cracks from craze marks.7. Report7.1 The report shall include the following:7.1.1 Identification of specimens, and statement whetherthey are whole pieces or cut and broken,7.1.2 Number of specimens tested,7.1.3 Identification of ink or dye solutions used in exami-nation of specime
26、ns, and7.1.4 Table listing each quenching as to oven temperatureand cycle number together with number of specimens failing ateach quenching; separate listings shall be made of failurescaused by crazing and failures caused by body cracking.NOTE 2Conventional whitewares (not subject to moisture expans
27、ion)that do not craze after being subjected to all phases of this test, up to andincluding three cycles at 300F (149C), can be expected to resist crazingunder all normal conditions of service. If special compositions are to betested, or if the resistance to abnormal service conditions is to beevalua
28、ted, a logical adaption of this test method may be made to suit theneed. If it is desired to use this procedure in conjunction with a productspecification, the test may be limited to one or more of these specifiedtemperatures.8. Precision and Bias8.1 No justifiable statements can be made either on t
29、heprecision or on the bias of this test method for testing crazingresistance of fired, glazed, ceramic whitewares by a thermalshock method since the test result merely states whether thereis conformance to the criteria for success specified in theprocedure.9. Keywords9.1 crazing resistance; fired gl
30、azed ceramic whiteware;thermal shock methodASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and
31、the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision
32、 of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shou
33、ldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).C 554 93 (2006)2
