1、Designation: C554 93 (Reapproved 2016)Standard Test Method forCrazing Resistance of Fired Glazed Ceramic Whitewares bya Thermal Shock Method1This standard is issued under the fixed designation C554; the number immediately following the designation indicates the year oforiginal adoption or, in the ca
2、se of revision, the year of last revision. A number 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 determination of the resis-tance to crazing of fired, glazed,
3、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 moist
4、ure expansion.NOTE 1Test Method C424 covers a method for determining resistanceto crazing induced by moisture expansion. Its use is generally confined totesting nonvitreous and semivitreous ceramic whitewares because theseproducts may be subject to such expansion. For whitewares with negli-gible moi
5、sture expansion (such as vitreous and impervious ware), thethermal shock method described herein is generally to be preferred.1.3 The values stated in inch-pound units are to be regardedas the standard. The values in parentheses are for informationonly.1.4 This standard does not purport to address a
6、ll 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. For a specifichazard statement, see Warning in 6.3.2. Referen
7、ced Documents2.1 ASTM Standards:2C424 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 that
8、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 the a
9、ppearance 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 semivitreous
10、 bodies, refer to Test MethodC424.4. 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 Wate
11、r 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 provided
12、 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. There
13、 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 be us
14、ed 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 inspe
15、cted for cracks by oblique1This test method is under the jurisdiction ofASTM Committee C21 on CeramicWhitewares and Related Productsand is the direct responsibility of SubcommitteeC21.03 on Methods for Whitewares and Environmental Concerns.Current edition approved July 1, 2016. Published July 2016.
16、Originally approvedin 1964. Last previous edition approved in 2011 as C554 93 (2011). DOI:10.1520/C0554-93R16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the st
17、andards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1lighting and application of a suitable ink or dye before the test.Only broken or cut specimen(s) free from cracks shall be used.The numbe
18、r of specimens 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) sh
19、ould be placed 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
20、less than 45 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
21、tothe quenching 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 l
22、ighting and 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 que
23、nching cycle.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
24、 cracks and 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 ar
25、e necessary 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-natio
26、n of specimens, 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 moi
27、sture expansion)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
28、 to beevaluated, 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
29、 either on theprecision 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 resistan
30、ce; fired glazed 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
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33、ing you shouldmake 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
34、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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 93 (2016)2
