1、Designation: C 385 58 (Reapproved 2009)Standard Test Method forThermal Shock Resistance of Porcelain-Enameled Utensils1This standard is issued under the fixed designation C 385; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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. T
3、histest 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 only
4、and 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 limitati
5、ons 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 surf
6、ace 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 wat
7、tage 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
8、 utensil.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” s
9、ignifies 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 he
10、ating 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 roo
11、m 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
12、 of 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 th
13、eutensil 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
14、started. 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 fo
15、r Porcelain Enamel and Ceramic-Metal Systems.Current edition approved April 15, 2009. Published June 2009. Originallyapproved in 1956. Last previous edition approved in 2004 as C 385 58 (2004)1.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite
16、d States.6.3 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 of the enamel f
17、rom 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 the utensil isrep
18、laced 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 previous test cy
19、cle.NOTE 6Example of typical results and calculation:Pan No.Cycle ofFailure Rating19721193947659736Average = 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 statements can be made
20、 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 enameling, will
21、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 respecting the validi
22、ty 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 standard is subjec
23、t 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 International Headquarte
24、rs. 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 below.This standard
25、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 service
26、astm.org (e-mail); or through the ASTM website(www.astm.org).TABLE 1 Heating ScheduleTime ofQuench, min:sCycleHot Plate SurfaceTemperature,F (C)3:00 1 475 6 10 (245 6 5.5)11:20 2 500 6 10 (260 6 5.5)19:40 3 525 6 10 (275 6 5.5)28:00 4 550 6 10 (287 6 5.5)36:20 5 575 6 10 (301 6 5.5)44:40 6 600 6 10 (315 6 5.5)53:00 7 625 6 10 (329 6 5.5)61:20 9 675 6 10 (357 6 5.5)69:40 11 725 6 10 (385 6 5.5)78:00 13 775 6 10 (413 6 5.5)86:20 15 825 6 10 (440 6 5.5)C 385 58 (2009)2
