1、Designation: D938 12 (Reapproved 2017) 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
2、adoption or, 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 U.S. Department of De
3、fense.1. Scope1.1 This test method covers determination of the congealingpoint of petroleum waxes, including petrolatum.1.2 The values stated in SI units are to be regarded as thestandard.1.2.1 ExceptionThe values given in parentheses are forinformation only.1.3 WARNINGMercury has been designated by
4、 manyregulatory agencies as a hazardous material that can causecentral nervous system, kidney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-teri
5、al Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfor addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.4 This standard does not purport to address all of th
6、esafety 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.NOTE 1This test method is an alternative to Test Method D127.Results o
7、btained are usually lower than the results obtained by TestMethod D127 IP 133, the amount of the deviation varying with thenature of the petroleum wax.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decisi
8、on on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D127 Test Method for Drop Melting Point of PetroleumWax, Including PetrolatumE1 Spe
9、cification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 congealing point, nof petroleum wax, that tempera-ture at which molten petroleum wax, when allowed to coolunder prescribed conditions, ceases to flow.3.1.2 thermometer, na device for determining temperatureusing one
10、of a variety of different principles.3.1.2.1 DiscussionA thermometer has two important ele-ments: the temperature sensor, within which some physicalchange occurs with temperature (for example, the bulb of aliquid-in-glass thermometer, or a thermistor in an electronicthermometer), plus some means of
11、converting this change intoa numerical value (for example, the scale on a liquid-in-glassthermometer, or a digital readout in the case of an electronicthermometer).4. Summary of Test Method4.1 A sample of wax is melted and a droplet is made toadhere to the bulb of a thermometer. Using a prewarmed fl
12、askas an air jacket, the droplet on the bulb is allowed to cool at afixed rate until it congeals. The congealing point is observed asthe temperature at which the droplet ceases to flow as thethermometer is turned.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,
13、 Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.10.0A on Physical/Chemical Properties.Current edition approved June 1, 2017. Published July 2017. Originally approvedin 1947. Last previous edition approved in 2012 as D938 12. DOI: 10.1520/D0938-12R17.2For referenced
14、ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Consho
15、hocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Orga
16、nization Technical Barriers to Trade (TBT) Committee.15. Significance and Use5.1 Congealing point is a wax property that is of interest tomany petroleum wax consumers. The procedure described heremeasures the temperature at which a sample being cooleddevelops a “set” or resistance to flow. At that t
17、emperature, thewax may be at or close to the solid state, or it may be semisolidand quite unctuous, depending on the composition of the waxor petrolatum being tested. In the case of petrolatums, congeal-ing property is associated with the formation of a gel structureas the sample cools.6. Apparatus6
18、.1 Thermometer, covering the range of 20 C to 100 C(68 F to 213 F).6.1.1 If used, mercury-in-glass thermometers shall conformto the requirements prescribed in Specification E1 or in thespecifications for IP Standard Thermometers:Thermometer NumberTemperature Range ASTM IP20 C to 100 C 54C 18C68 F to
19、 213 F 54F 18F6.1.2 Thermometric devices such as RTDs, thermistors, orother liquid-in-glass thermometers of equal or better accuracy,and covering the appropriate temperature range, may be used.6.2 Erlenmeyer Flask, 125 mL, glass, to serve as a ther-mometer jacket.6.3 Cork or Rubber Stopper, for atta
20、ching the thermometerto the Erlenmeyer flask.7. Procedure7.1 Adjust the thermometer through the stopper so that thebottom of the bulb will be 10 mm to 15 mm above the bottomof the Erlenmeyer flask when the stopper is fitted snugly in theflask. After making this adjustment, remove the thermometerand
21、stopper from the flask, being careful not to change theposition of the stopper relative to the thermometer stem.7.2 Place approximately 50 g of sample, which is represen-tative of the material under inspection, in a porcelain evapo-rating dish or other suitable container.7.3 Place the empty Erlenmey
22、er flask (without the ther-mometer assembly) and the container holding the specimen ina temperature-controlled oven set at 99 C 6 3 C (210 F 65 F) until the specimen and the flask reach oven temperature.NOTE 2For nonreferee, routine testing of samples known to have lowcongealing points, the oven may
23、 be set at a lower temperature, but it mustbe at least 11 C (20 F) above the expected congealing point of thesample.7.4 Remove the specimen from the oven and completelyimmerse the thermometer bulb in it without covering any partof the thermometer stem with specimen. Gently stir thespecimen with the
24、thermometer until the temperature hasstopped rising.7.5 While holding the thermometer bulb in the molten waxspecimen, remove the heated flask from the oven, using a towelor gloves to protect the hands. Now carefully remove thethermometer from the specimen, taking care to retain arelatively large dro
25、p of specimen adhering to the bulb. Holdingthe thermometer in a horizontal position, firmly fit the ther-mometer and stopper into the flask. Keep the assembly in ahorizontal position.7.6 While observing the drop on the thermometer bulb at aneye level position, rotate the thermometer and flask about
26、ahorizontal axis. Use a steady and even rate for each continuousfull revolution, and complete each revolution in not less than2 s, nor more than 3 s. Do not pause at the completion of eachrevolution any longer than required to reindex the fingers forthe next full and continuous rotation (Note 3). Wh
27、en the dropis observed to rotate with the bulb, immediately read thethermometer to the nearest 0.2 C (0.5 F) and record thisdetermination. Make a repeat determination on the wax speci-men. If the variation of these two determinations does notexceed 1 C (2 F), record the average of these determinatio
28、nsas the congealing point of the specimen under test. If thevariation of two determinations is greater than 1 C (2 F),make one additional determination and record the average ofthe three determinations as the congealing point.NOTE 3Operators should periodically check themselves for compli-ance with
29、this turning rate. The brief pause time is not to be included inthe 2 s to 3 s rotation time.8. Report8.1 Report the average of the multiple determinations as thecongealing point, in C (F), to one decimal place.9. Precision and Bias9.1 The precision of this test method is not known to havebeen obtai
30、ned in accordance with RR:D02-1007, “Manual onDetermining Precision Data for ASTM Methods on PetroleumProducts.”9.2 The precision of this test method as determined bystatistical examination of interlaboratory results is as follows:9.2.1 RepeatabilityThe difference between two testresults, obtained b
31、y the same operator with the same apparatusunder constant operating conditions on identical test material,would in the long run, in the normal and correct operation ofthe test method, exceed the following values only in one casein twenty:Distillate waxes 0.5 C (1.0 F)Residual waxes, including petrol
32、atums 1.0 C (2.0 F)9.2.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, inthe long run, in the normal and correct operation of the testmethod, exceed the following values onl
33、y in one case intwenty:Distillate waxes 1.5 C (2.5 F)Residual waxes, including petrolatums 2.5 C (4.5 F)9.3 BiasThe procedure in this test method for measuringthe congealing point of petroleum waxes has no bias becausethe value of the congealing point can be defined only in termsof a test method.10.
34、 Keywords10.1 congealing point; petrolatum; petroleum waxesD938 12 (2017)2ASTM 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 of the validity
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