1、Designation: C370 12 (Reapproved 2016)Standard Test Method forMoisture Expansion of Fired Whiteware Products1This standard is issued under the fixed designation C370; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 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 elon-gation of whiteware bodies caused by rehydration as a result ofautoc
3、lave treatment.1.2 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 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.
4、2. Significance and Use2.1 This test method provides means to determine increasesin physical dimension of fired whiteware materials whichdevelop from the reaction of water and water vapor at elevatedpressures and temperatures. These reactions can occur in timeat normal atmospheric pressures and temp
5、eratures; changes inphysical dimensions from water can influence the integrity andstability of an installation. In the case of glazed ware, moistureexpansion can lead to crazing.3. Apparatus3.1 Autoclave, that can safely be operated at 150 psi(1 MPa), and that has sufficient capacity to contain at l
6、east fivespecimens. The apparatus shall be equipped with a safetyvalve, a pressure gage accurate within 2 % of the scale range,and a source of heat of sufficient capacity to ensure a constantsteam pressure within the autoclave.3.2 Micrometer, at least 3 to 4 in. (76 to 102 mm), readingto 0.0001 in.
7、(0.003 mm), or a dial indicator graduated in0.0001-in. increments.3.3 Fixture, for mounting the micrometer or dial indicatorand for holding the specimen in such a manner that reproduc-ible results can be obtained. A fused silica reference shall beused to calibrate the fixture before each measurement
8、.4. Test Specimen4.1 The specimens shall be unglazed, rod-like in shape,about 3 to 4 in. (76 to 102 mm) long, and preferably cut fromthe center of production pieces of ware. The greatest thicknessshall not exceed 0.75 in. (19 mm), and the least dimension shallbe not less than 0.10 in. (2.5 mm).4.2 T
9、he specimens shall be cut to size and measuredimmediately after coming from the kiln or shall be stored in adesiccator until they can be cut and measured.4.3 The ends of the specimens shall be cut perpendicular tothe length and parallel to each other. They then shall besmoothed with emery cloth and,
10、 finally, with jewelers rouge.4.4 At least five specimens shall be tested.5. Procedure5.1 Mark the specimens for identification and measure themwith the micrometer or the dial indicator to the nearest 0.0001in. (0.003 mm). Apply a reference mark to the specimens fororientation in the measuring fixtu
11、re.5.2 Locate the specimens above the water in the autoclaveand subject them to 150-psi (1-MPa) steam pressure for 5 h.Maximum pressure shall be reached in not less than 45 min normore than 1 h.After the 5-h treatment, immediately release thesteam pressure by opening the blow-off valve.5.3 After rem
12、oval from the autoclave, dry the specimens toconstant weight at a temperature not exceeding 110C and coolthem to room temperature.5.4 Measure the dry specimens to the nearest 0.0001 in.(0.003 mm) on the micrometer or dial indicator. To minimizeerrors of measurement caused by the expansion of thespec
13、imen, the temperature of the specimen should be approxi-mately the same for initial and final measurements.6. Calculation6.1 Calculate the percent of moisture expansion, based onthe original length of the specimens, as follows:O 5 L/L1! 3100 (1)where:O = moisture expansion, percent;1This test method
14、 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 Environmental Concerns.Current edition approved Nov. 1, 2016. Published November 2016. Originallyapproved in 1955. Last previ
15、ous edition approved in 2012 as C370 12. DOI:10.1520/C0370-12R16.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1L = difference between final and original length of thespecimen (L2 L1), in. (mm);L1= original length of specimen, in. (m
16、m); andL2= length of specimen after autoclave treatment, in.(mm).7. Report7.1 Report the following information:7.1.1 General description of the material being tested,7.1.2 The average percentage moisture expansion of the lot,and7.1.3 Individual values of moisture expansion for eachspecimen.8. Precis
17、ion and Bias8.1 Precision depends on the precision of the micrometerused. A bias statement cannot be made due to lack ofrecognized standards.9. Keywords9.1 fired whiteware products; moisture expansionASTM International takes no position respecting the validity of any patent rights asserted in connec
18、tion with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsib
19、le technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful con
20、sideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100
21、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). 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:/ 12 (2016)2
