1、Designation: C 385 58 (Reapproved 2004)e1Standard 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
2、 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.e1NOTEKeywords were added editorially in September 2004.1. Scope1.1 This test method covers the determination of the res
3、is-tance of porcelain-enameled utensils to thermal shock. Thistest method is adaptable to any porcelain-enamel utensil thatcan be filled with water to a depth of 1 in. (25 mm).1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsib
4、ility 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.2. Apparatus2.1 Hot Plate, capable of maintaining over its entire surfacea uniform temperature, that is, less than 20F (6.7C) varia-tion ov
5、er 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 surface temperature ofthe hot plate, determined by any suitable surface temperaturemeasuring device, may be varied by changing the wattageinput to the hot plate
6、. If the hot plate surface temperature becalibrated to wattage input, the desired temperature may thenbe set by adjusting wattage input. The wattage 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
7、second hand and an integrating minute hand.2.3 Container, suitable for holding approximately 4 gal ofwater.2.4 Container, for pouring water into 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 ha
8、rd, distilled water isrecommended.4. Test Specimens4.1 The test specimens shall consist of five identical uten-sils.NOTE 2“Identical utensils” signifies 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 temperat
9、ure 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 heating 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 re
10、quired 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 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 p
11、late 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 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
12、 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 theutensil 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 t
13、emperature measure-ments during the test. The surface temperature of the hot plate should becalibrated against wattage input before the test is 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 unde
14、r the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.12 onMaterials for Porcelain Enamel and Ceramic-Metal Systems.Current edition approved Aug. 1, 2004. Published September 2004. Originallyapproved in 1956. Last previous edi
15、tion approved in 1998 as C 385 58 (1998).1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United 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. Con
16、tinue the test until the utensilfails or has withstood quenching after the 825F (440C)heating period.NOTE 5A failure is the removal 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
17、. 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 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
18、 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 cycle.NOTE 6Example of typical results and calculation:Pan No.Cycle ofFailure Rating19721193947659736Average = 36/5 = 7.2 cycles8. Report8.1 Report the ave
19、rage of the ratings for five identicalutensils as the thermal shock resistance value.9. Precision and Bias9.1 No justifiable statements 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
20、single, specific size and design of utensil. Sincedesign, base metal composition, fabrication, and processing, aswell as porcelain enameling, will give rise to variables in thethermal shock resistance of porcelain-enameled utensils, eachdesign of utensil should be considered separately.10. Keywords1
21、0.1 glass coating; porcelain enamel; porcelain enameledutensils; thermal shock resistanceASTM 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 o
22、f 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 responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn.
23、 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 consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comm
24、ents 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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or
25、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).TABLE 1 Heating ScheduleTime ofQuench, min:sCycleHot Plate SurfaceTemperature,F (C)3:00 1 47
26、5 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 (2004)e12
