1、Designation: D938 05D938 12 British Standard 5088Designation: 76/70(95)Standard Test Method forCongealing Point of Petroleum Waxes, IncludingPetrolatum1This standard is issued under the fixed designation D938; the number immediately following the designation indicates the year oforiginal adoption or
2、, in the case 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.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1
3、.1 This test method covers determination of the congealing point of petroleum waxes, including petrolatum.1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.1.3 WARNINGMercury has been designated by many regulatory agencies
4、as a hazardous material that can cause centralnervous system, kidney and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Cautionshould be taken when handling mercury and mercury containing products. See the applicable product Material Safety Data Sheet(MSD
5、S) for details and EPAs websitehttp:/www.epa.gov/mercury/faq.htmfor additional information. Users should be awarethat selling mercury and/or mercury containing products into your state or country may be prohibited by law.1.4 This standard does not purport to address all of the safety concerns, if an
6、y, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.NOTE 1This test method is an alternative to Test Method D127. Results obtained are usually lower
7、 than the results obtained by Test MethodD127 IP 133, the amount of the deviation varying with the nature of the petroleum wax.2. Referenced Documents2.1 ASTM Standards:2D127 Test Method for Drop Melting Point of Petroleum Wax, Including PetrolatumE1 Specification for ASTM Liquid-in-Glass Thermomete
8、rs3. Terminology3.1 Definitions:3.1.1 congealing point, nof petroleum wax, that temperature at which molten petroleum wax, when allowed to cool underprescribed conditions, ceases to flow.3.1.2 thermometer, na device for determining temperature using one of a variety of different principles.3.1.2.1 D
9、iscussionA thermometer has two important elements: the temperature sensor, within which some physical change occurs with temperature(for example, the bulb of a liquid-in-glass thermometer, or a thermistor in an electronic thermometer), plus some means ofconverting this change into a numerical value
10、(for example, the scale on a liquid-in-glass thermometer, or a digital readout in thecase of an electronic thermometer).1 This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.10.0Aon Physical/Chemic
11、al Properties.Current edition approved Nov. 1, 2005Dec. 1, 2012. Published November 2005February 2013. Originally approved in 1947. Last previous edition approved in 20042005as D93804.05. DOI: 10.1520/D0938-05.10.1520/D0938-12.2 For referencedASTM standards, visit theASTM website, www.astm.org, or c
12、ontactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have
13、been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official docum
14、ent.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Summary of Test Method4.1 A sample of wax is melted and a droplet is made to adhere to the bulb of a thermometer.
15、Using a prewarmed flask as anair jacket, the droplet on the bulb is allowed to cool at a fixed rate until it congeals. The congealing point is observed as thetemperature at which the droplet ceases to flow as the thermometer is turned.5. Significance and Use5.1 Congealing point is a wax property tha
16、t is of interest to many petroleum wax consumers. The procedure described heremeasures the temperature at which a sample being cooled develops a “set” or resistance to flow. At that temperature, the wax maybe at or close to the solid state, or it may be semisolid and quite unctuous, depending on the
17、 composition of the wax or petrolatumbeing tested. In the case of petrolatums, congealing property is associated with the formation of a gel structure as the sample cools.6. Apparatus6.1 Thermometer, having covering the following range and conforming to the requirements prescribed in Specification o
18、f 20 to100C (68 to 213F).E1 or in the specifications for IP Standard Thermometers:Thermometer NumberTemperature Range ASTM IP20 to 100C 54C 18C68 to 213F 54F 18F6.1.1 If used, mercury-in-glass thermometers shall conform to the requirements prescribed in Specification E1 or in thespecifications for I
19、P Standard Thermometers:Thermometer NumberTemperature Range ASTM IP20 to 100C 54C 18C68 to 213F 54F 18F6.1.2 Thermometric devices such as RTDs, thermistors, or other liquid-in-glass thermometers of equal or better accuracy, andcovering the appropriate temperature range, may be used.6.2 Erlenmeyer Fl
20、ask, 125-mL, glass, to serve as a thermometer jacket.6.3 Cork or Rubber Stopper, for attaching the thermometer to the Erlenmeyer flask.7. Procedure7.1 Adjust the thermometer through the stopper so that the bottom of the bulb will be 10 to 15 mm above the bottom of theErlenmeyer flask when the stoppe
21、r is fitted snugly in the flask.After making this adjustment, remove the thermometer and stopperfrom the flask, being careful not to change the position of the stopper relative to the thermometer stem.7.2 Place approximately 50 g of sample, which is representative of the material under inspection, i
22、n a porcelain evaporating dishor other suitable container.7.3 Place the empty Erlenmeyer flask (without the thermometer assembly) and the container holding the specimen in atemperature-controlled oven set at 99 6 3C (210 6 5F) until the specimen and the flask reach oven temperature.NOTE 2For nonrefe
23、ree, routine testing of samples known to have low congealing points, the oven may be set at a lower temperature, but it must beat least 11C (20F) above the expected congealing point of the sample.7.4 Remove the specimen from the oven and completely immerse the thermometer bulb in it without covering
24、 any part of thethermometer stem with specimen. Gently stir the specimen with the thermometer until the mercury column temperature hasstopped rising.7.5 While holding the thermometer bulb in the molten wax specimen, remove the heated flask from the oven, using a towel orgloves to protect the hands.
25、Now carefully remove the thermometer from the specimen, taking care to retain a relatively large dropof specimen adhering to the bulb. Holding the thermometer in a horizontal position, firmly fit the thermometer and stopper intothe flask. Keep the assembly in a horizontal position.7.6 While observin
26、g the drop on the thermometer bulb at an eye level position, rotate the thermometer and flask about ahorizontal axis. Use a steady and even rate for each continuous full revolution, and complete each revolution in not less than 2s, nor more than 3 s. Do not pause at the completion of each revolution
27、 any longer than required to reindex the fingers for the nextfull and continuous rotation (Note 3). When the drop is observed to rotate with the bulb, immediately read the thermometer to thenearest 0.2C (0.5F) and record this determination. Make a repeat determination on the wax specimen. If the var
28、iation of thesetwo determinations does not exceed 1C (2F), record the average of these determinations as the congealing point of the specimenunder test. If the variation of two determinations is greater than 1C (2F), make one additional determination and record theaverage of the three determinations
29、 as the congealing point.NOTE 3Operators should periodically check themselves for compliance with this turning rate. The brief pause time is not to be included in the 2 to3-s rotation time.D938 1228. Report8.1 Report the average of the multiple determinations as the congealing point, in C (F), to on
30、e decminaldecimal place.9. Precision and Bias9.1 The precision of this test method is not known to have been obtained in accordance with RR:D02-1007, “Manual onDetermining Precision Data for ASTM Methods on Petroleum Products.”9.2 The precision of this test method as determined by statistical examin
31、ation of interlaboratory results is as follows:9.2.1 RepeatabilityThe difference between two test results, obtained by the same operator with the same apparatus underconstant operating conditions on identical test material, would in the long run, in the normal and correct operation of the testmethod
32、, exceed the following values only in one case in twenty:Distillate waxes 0.5C (1.0F)Residual waxes, including petrolatums 1.0C (2.0F)9.2.2 ReproducibilityThe difference between two single and independent results obtained by different operators working indifferent laboratories on identical test mate
33、rial would, in the long run, in the normal and correct operation of the test method,exceed the following values only in one case in twenty:Distillate waxes 1.5C (2.5F)Residual waxes, including petrolatums 2.5C (4.5F)9.3 BiasThe procedure in this test method for measuring the congealing point of petr
34、oleum waxes has no bias because thevalue of the congealing point can be defined only in terms of a test method.10. Keywords10.1 congealing point; petrolatum; petroleum waxesSUMMARY OF CHANGESSubcommittee D02.10 has identified the location of selected changes to this standard since the last issue(D93
35、804)05) that may impact the use of this standard. (Approved Nov. 1, 2005.)(1) Added 3.1.2.(2) Revised 8.16.1 and 7.4.Subcommittee D02.10 has identified the location of selected changes to this standard since the last issue(D93892 (1998)1 ) that may impact the use of this standard. (Approved May 1, 2
36、004.)(1) Changed reading and reporting of results obtained in Celsius from to the nearest 0.25C to 0.2C in 7.6 and 8.1.ASTM 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 expressl
37、y 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 responsible technical committee and must be reviewed every five years andif not revised, e
38、ither 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 consideration at a meeting of theresponsible technical committee, which you may atten
39、d. 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 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. In
40、dividual 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 ASTM website (www.astm.org/COPYRIGHT/).D938 123
