1、Designation: C385 58 (Reapproved 2014)Standard Test Method forThermal Shock Resistance of Porcelain-Enameled Utensils1This standard is issued under the fixed designation C385; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the yea
2、r 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 of porcelain-enameled utensils to thermal shock. Thi
3、stest method is adaptable to any porcelain-enamel utensil thatcan be filled with water to a depth of 1 in. (25 mm).1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyan
4、d are not considered standard.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 appro-priate safety and health practices and determine the applica-bility of regulatory limitation
5、s prior to use.2. Apparatus2.1 Hot Plate, capable of maintaining over its entire surfacea uniform temperature, that is, less than 20F (6.7C) varia-tion over the entire surface. Surface temperature of the hotplate shall be capable of being adjusted from 475 to825 6 10F (245 to 440 6 5.5C). The surfac
6、e temperature ofthe hot plate, determined by any suitable surface temperaturemeasuring device, may be varied by changing the wattageinput to the hot plate. If the hot plate surface temperature becalibrated to wattage input, the desired temperature may thenbe set by adjusting wattage input. The watta
7、ge input or similarcalibration shall be made for each surface temperature (see 6.2and 6.3).2.2 Timing Device, a clock or similar instrument having asweep second hand and an integrating minute hand.2.3 Container, suitable for holding approximately 4 gal ofwater.2.4 Container, for pouring water into u
8、tensil.2.5 Sponge, for wiping utensil dry.3. Quenching Water3.1 Either tap or distilled water shall be used.NOTE 1In areas where tap water is extremely hard, distilled water isrecommended.4. Test Specimens4.1 The test specimens shall consist of five identical uten-sils.NOTE 2“Identical utensils” sig
9、nifies utensils of the same size, shape,and finish.5. Preparations for Test5.1 Level the hot plate. Switch on the hot plate and adjustthe surface temperature to 475 6 10F (245 6 5.5C). Allowthe hot plate to preheat at this temperature for at least1htoobtain a uniform temperature over the entire heat
10、ing surface.5.2 Place the quenching water in a large container. Adjustthe temperature of the water to 70 6 2F (21 6 1C). Measureout the amount of water required to fill a test utensil to a depthof 1 in. (25 mm); this amount of water shall be used forquenching.NOTE 3The test utensils must be at room
11、temperature at the start ofthe test.6. Procedure6.1 Center a dry utensil directly on the preheated hot plate.After 3 min remove the utensil from the hot plate andimmediately fill the utensil to a depth of 1 in. (25 mm) withquenching water. After 10 s pour out the quenching water andwipe the inside o
12、f the utensil with a wrung-out damp sponge.After a total nonheating period of 20 s replace the utensil on thehot plate.6.2 Immediately after centering the utensil on the hot plate,adjust the input to the hot plate so that the hot plate surfacetemperature will reach 500 6 10F (260 6 5.5C). Allow theu
13、tensil to heat dry for 8 min with the hot plate adjusted so thatthis new surface temperature will be reached.NOTE 4Do not remove the utensil for surface temperature measure-ments during the test. The surface temperature of the hot plate should becalibrated against wattage input before the test is st
14、arted. The surfacetemperature of the hot plate is the maximum temperature to be reachedduring the 8-min heating period (see 2.1).1This test method is under the jurisdiction ofASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 onMaterials for
15、Porcelain Enamel and Ceramic-Metal Systems.Current edition approved May 1, 2014. Published May 2014. Originallyapproved in 1956. Last previous edition approved in 2009 as C385 58 (2009).DOI: 10.1520/C0385-58R14.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
16、9428-2959. United States16.3 After the 8-min heating period, remove the utensil andquench as before. Repeat this procedure according to theschedule given in Table 1. Continue the test until the utensilfails or has withstood quenching after the 825F (440C)heating period.NOTE 5A failure is the removal
17、 of the enamel from the utensil,generally accompanied by a cracking noise, during the heating period.Fish-scaling and crazing are not considered thermal-shock failures.7. Rating Test Specimens7.1 A cycle begins when the utensil is placed on the hotplate and ends after the quenching and just before t
18、he utensil isreplaced on the hot plate.7.2 The utensil shall be rated for the number of cycles it haspassed without failure. For example, a utensil failing in theseventh cycle would have a rating of “6.” If the utensil fails inthe ninth cycle or in a subsequent cycle, the rating shall be thatof the
19、previous test cycle.NOTE 6Example of typical results and calculation:Pan No.Cycle ofFailure Rating197211 93947659736Average = 36/5 = 7.2 cycles8. Report8.1 Report the average of the ratings for five identicalutensils as the thermal shock resistance value.9. Precision and Bias9.1 No justifiable state
20、ments can be made regarding theprecision and bias of this test method due to the fact that it isapplicable to a wide variety of utensils of different designrather than a single, specific size and design of utensil. Sincedesign, base metal composition, fabrication, and processing, aswell as porcelain
21、 enameling, will give rise to variables in thethermal shock resistance of porcelain-enameled utensils, eachdesign of utensil should be considered separately.10. Keywords10.1 glass coating; porcelain enamel; porcelain enameledutensils; thermal shock resistanceASTM International takes no position resp
22、ecting 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 the riskof infringement of such rights, are entirely their own responsibility.This s
23、tandard 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 of this standard or for additional standardsand should be addressed to ASTM Interna
24、tional 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 shouldmake your views known to the ASTM Committee on Standards, at the address shown bel
25、ow.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
26、(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 ASTM website (www.astm.org/COPYRIGHT/).TABLE 1 Heating ScheduleTime ofQuench, min:sCycleHot Plate SurfaceTemperature,F (C)3:00 1 475 10 (245 5.5)11:20 2 50010(2605.5)19:40 3 525 10 (275 5.5)28:00 4 550 10 (287 5.5)36:20 5 575 10 (301 5.5)44:40 6 600 10 (315 5.5)53:00 7 625 10 (329 5.5)61:20 9 675 10 (357 5.5)69:40 11 725 10 (385 5.5)78:00 13 775 10 (413 5.5)86:20 15 825 10 (440 5.5)C385 58 (2014)2
