1、Designation: D 938 05Designation: 76/70(95)An American National StandardBritish Standard 5088Standard Test Method forCongealing Point of Petroleum Waxes, IncludingPetrolatum1This standard is issued under the fixed designation D 938; the number immediately following the designation indicates the year
2、 oforiginal adoption or, in the case of revision, the 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.This standard has been approved for use by agencies of the Departme
3、nt of Defense.1. Scope*1.1 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. The values given in parentheses are for informationonly.1.3 This standard does not purport to address
4、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 limitations prior to use.NOTE 1This test method is an alternative to Test Method D 127
5、.Results obtained are usually lower than the results obtained by TestMethod D 127 IP 133, the amount of the deviation varying with thenature of the petroleum wax.2. Referenced Documents2.1 ASTM Standards:2D 127 Test Method for Drop Melting Point of PetroleumWax, Including PetrolatumE1 Specification
6、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.4. Summary of Test Method4.1 A sample of wax is melted and a droplet is made
7、toadhere to the bulb of a thermometer. Using a prewarmed flaskas 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.5. Significance and Use5.1 C
8、ongealing 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 temperature, thewax may be at or close to the solid state, or it may be semisolidan
9、d 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. Apparatus6.1 Thermometer, having the following range and conform-ing to the requirements pre
10、scribed in Specification E1or in thespecifications for IP Standard Thermometers:Thermometer NumberTemperature Range ASTM IP20 to 100C 54C 18C68 to 213F 54F 18F6.2 Erlenmeyer Flask, 125-mL, glass, to serve as a ther-mometer jacket.6.3 Cork or Rubber Stopper, for attaching the thermometerto the Erlenm
11、eyer flask.7. Procedure7.1 Adjust the thermometer through the stopper so that thebottom of the bulb will be 10 to 15 mm above the bottom of theErlenmeyer flask when the stopper is fitted snugly in the flask.After making this adjustment, remove the thermometer andstopper from the flask, being careful
12、 not to change the positionof 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.1This test method is under the jurisdiction of ASTM Committee D02
13、 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.10 on Properties of Petroleum Wax.Current edition approved Nov. 1, 2005. Published November 2005. Originallyapproved in 1947. Last previous edition approved in 2004 as D 93804.2For referenced ASTM standards, vis
14、it 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International,
15、 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.3 Place the empty Erlenmeyer flask (without the ther-mometer assembly) and the container holding the specimen ina temperature-controlled oven set at 99 6 3C (210 6 5F)until the specimen and the flask reach oven te
16、mperature.NOTE 2For nonreferee, routine testing of samples known to have lowcongealing points, the oven may be set at a lower temperature, but it mustbe at least 11C (20F) above the expected congealing point of the sample.7.4 Remove the specimen from the oven and completelyimmerse the thermometer bu
17、lb in it without covering any partof the thermometer stem with specimen. Gently stir thespecimen with the thermometer until the mercury column 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
18、the hands. Now carefully remove thethermometer from the specimen, taking care to retain arelatively large drop 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 Whil
19、e observing the drop on the thermometer bulb at aneye level position, rotate the thermometer and flask about ahorizontal axis. Use a steady and even rate for each continuousfull revolution, and complete each revolution in not less than 2s, nor more than 3 s. Do not pause at the completion of eachrev
20、olution any longer than required to reindex the fingers forthe next full and continuous rotation (Note 3). When the dropis observed to rotate with the bulb, immediately read thethermometer to the nearest 0.2C (0.5F) and record thisdetermination. Make a repeat determination on the wax speci-men. If t
21、he variation of these two determinations does notexceed 1C (2F), record the average of these determinationsas the congealing point of the specimen under test. If thevariation of two determinations is greater than 1C (2F), makeone additional determination and record the average of thethree determinat
22、ions as the congealing point.NOTE 3Operators should periodically check themselves for compli-ance with this turning rate. The brief pause time is not to be included inthe 2 to 3-s rotation time.8. Report8.1 Report the average of the multiple determinations as thecongealing point, in C (F), to one de
23、cminal place.9. Precision and Bias9.1 The precision of this test method is not known to havebeen obtained 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 inter
24、laboratory results is as follows:9.2.1 RepeatabilityThe difference between two test re-sults, obtained by 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 f
25、ollowing values only in one casein twenty:Distillate waxes 0.5C (1.0F)Residual waxes, including petrolatums 1.0C (2.0F)9.2.2 ReproducibilityThe difference between two singleand independent results obtained by different operators work-ing in different laboratories on identical test material would, in
26、the long run, in the normal and correct operation of the testmethod, exceed the following values only in one case intwenty:Distillate waxes 1.5C (2.5F)Residual waxes, including petrolatums 2.5C (4.5F)9.3 BiasThe procedure in this test method for measuringthe congealing point of petroleum waxes has n
27、o bias becausethe value of the congealing point can be defined only in termsof 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(D 93804) that may imp
28、act the use of this standard. (Approved Nov. 1, 2005.)(1) Revised 8.1.Subcommittee D02.10 has identified the location of selected changes to this standard since the last issue(D 93892 (1998)e1) that may impact the use of this standard. (Approved May 1, 2004.)(1) Changed reading and reporting of resu
29、lts obtained inCelsius from to the nearest 0.25C to 0.2C in 7.6 and 8.1.D938052ASTM 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 vali
30、dity 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. Your comm
31、ents 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 comments have
32、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 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).D938053
