1、Designation: D 1177 07Standard Test Method forFreezing Point of Aqueous Engine Coolants1This standard is issued under the fixed designation D 1177; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number
2、 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 Department of Defense.1. Scope1.1 This test method covers the determination of the freez-ing
3、point of an aqueous engine coolant solution in thelaboratory.NOTE 1Where solutions of specific concentrations are to be tested,they shall be prepared from representative samples as directed in PracticeD 1176. Secondary phases separating on dilution need not be separated.NOTE 2These products may also
4、 be marketed in a ready-to-use form(prediluted).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 all of thesafety concerns, if any, associated with its use. It is theresponsibili
5、ty 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. Referenced Documents2.1 ASTM Standards:2D 1176 Practice for Sampling and Preparing Aqueous So-lutions of Engine Coolants or Antirusts for T
6、esting Pur-posesE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 freezing pointthe temperature at which crystalliza-tion begins in the absence of supercooling, or the maximumtemperature reached immediately after initial crystal formationin the case of superco
7、oling, or the temperature at which solidcrystals, formed on cooling, disappear when the temperature ofthe specimen is allowed to rise.4. Summary of Test Method4.1 This test method involves the determination of thetime-temperature curve prior to freezing and the determinationof the horizontal or flat
8、tened portion of the freezing curve. Thefreezing point is taken as the intersection of projections of thecooling curve and the freezing curve. If the solution super-cools, the freezing point is the maximum temperature reachedafter supercooling.5. Significance and Use5.1 The freezing point of an engi
9、ne coolant indicates thecoolant freeze protection.5.2 The freezing point of an engine coolant may be used todetermine the approximate glycol content, provided the glycoltype is known.6. Apparatus6.1 Freezing Point Apparatus, shown assembled in Fig. 1,consisting of the following:6.1.1 Cooling Bath, i
10、n which the refrigerant is contained,consisting of a standard 1.9-L (2-qt) Dewar flask. The flaskmay be silvered or unsilvered, and is supported in a close-fitting container.Apad of glass wool is placed in the bottom ofthe flask to protect it from damage by tip of freezing tube.6.1.2 Freezing Tube3c
11、onsisting of a 200-mL (6.8-oz.)unevacuated, unsilvered Dewar flask. The tube is closed by acork having a central hole for the thermocouple or thermom-eter, a second hole placed to one side for passage of the stirringrod, and a third hole for introducing wire for seeding atappropriate time.6.1.3 Stir
12、ring Mechanism, consisting of a five-coil stirrerformed of stainless steel wire 1.6 mm (116 in.) in diameter. Thecoils are so spaced that, in the extreme upward position duringoperation, no coils are exposed above the surface of thesample. The stirrer is agitated by means of an ordinarywindshield wi
13、per motor or other motor devices, operatingthrough suitable linkages so as to provide linear motion of the1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and is the direct responsibility of Subcommittee D15.03 on PhysicalProperties.Current edition approved April 1
14、, 2007. Published April 2007. Originallyapproved in 1951. Last previous edition approved in 2005 as D 1177 05.2For referenced 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 st
15、andards Document Summary page onthe ASTM website.3For routine work, a tube with a seeding tip as described in the paper by R. E.Mallonee and F. L. Howard, “The Determination of Freezing Point of EngineAntifreeze,” in the February 1951 issue of the ASTM Bulletin may be used. (See Fig.2.)1Copyright AS
16、TM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.stirrer. The length of the stroke is adjusted so that the coil justclears the bottom of the freezing-point tube at low point of thestroke.6.1.4 Temperature MeasurementA resistance thermom-eter or a
17、multi-junction copper-constantan thermocouple maybe used with suitable measuring instruments, providing thesegive an over-all sensitivity of 0.1C (0.2F). The instrumentshall be calibrated before each series of determinations byusing suitable reference standards. Platinum resistance ther-mometers hav
18、e been adopted as a standard by the NationalInstitute of Standards and Technology (NIST) and are recom-mended for this standard.NOTE 3ASTM Coolant Freezing Point Temperature Measuring In-struments having a range from 37 to + 2C (35 to + 35F) or 54to 15C (65 to + 5F) and conforming to the requirement
19、s for Ther-mometers 75F or 76F as prescribed in Specifications E1, may be usedwhere less accuracy is acceptable provided reference standards are usedfor calibration purposes.7. Refrigerant7.1 The refrigerant shall consist of solid carbon dioxide inalcohol or in other suitable bath liquids.NOTE 4A la
20、yer of dry ice, at least 13 mm (12 in.) thick, must bemaintained in the bottom or on the top of the cooling bath during adetermination, depending on the bath liquid used. Adequate precautionsshould be taken against fire hazards or toxic effects of bath liquids, orboth.7.2 Liquid nitrogen may be used
21、 as the refrigerant when thefreezing point of the coolant is 46C (50F) or lower.(WarningThe liquid nitrogen should be discarded after eachdays use to avoid the possibility of explosion due to dissolvedoxygen and inadvertent mixing with organic coolant materi-als.)FIG. 1 Assembly of Freezing Point Ap
22、paratusFIG. 2 Bottom of Freezing Tube Showing Seeding TipD11770728. Procedure8.1 Assemble the apparatus as shown in Fig. 1, with norefrigerant and no sample of coolant yet in place. Check theoperation of the stirring mechanism after assembly to be surethat all parts operate freely.8.2 Fill the Dewar
23、 flask surrounding the freezing tube withthe refrigerant liquid, adding pieces of solid carbon dioxidefrom time to time to maintain conditions mentioned in Note 4.Temporarily remove the stopper from the freezing tube andintroduce 75 to 100 mL (2.65 to 3.4 oz.) of the sample.NOTE 5The sample may be p
24、recooled to approximately 8C (15F)above the expected freezing point before introducing it into the freezingtube.8.3 Start the stirrer and adjust it to operate at 60 to 80strokes per min (Note 6). As soon as stirring is begun, observeand record the temperature at regular intervals of time. As theexpe
25、cted freezing point is approached, the time intervalsshould be quite short, 15 s if possible.At the expected freezingpoint, seeding should be started to prevent supercooling. Thiscan be accomplished by introducing a wire which has a smallportion of the solution being tested frozen on its tip. It is
26、mostconvenient to freeze this solution in a small test tube inserteddirectly into the cooling bath.NOTE 6Astroke is considered as a complete cycle of one upward andone downward motion of the stirrer.NOTE 7The cooling rate must be less than 1C (2F)/min at the timethe solution is seeded.8.4 Continue t
27、emperature readings at regular intervals for atleast 10 min after the apparent freezing point.9. Report9.1 Plot the observed temperature against time on rectangu-lar coordinate paper. Where the curve shows a definite flat orplateau during freezing, the freezing point is taken as theintersection of p
28、rojections of the cooling curve and the flat orhorizontal plateau portion of the freezing curve (see Fig. 3(a).If the solution supercools, the freezing point is the maximumtemperature reached immediately after supercooling (see Fig.3(b).NOTE 8The amount of supercooling should be held to a minimum. I
29、fthe supercooling exceeds 1C (2F) the test should be rejected.10. Precision and Bias10.1 Precision and Bias results are as follows:4C FRepeatability of Test for a Given Analyst 0.17 0.31Intermediate Precision of Test for a Given Laboratory 0.88 1.58Reproducibility of Test Across Laboratories 1.30 2.
30、3411. Keywords11.1 aqueous engine coolants; engine coolants; engine cool-ants; freezing pointASTM 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 determinati
31、on 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, either reapproved or withdr
32、awn. 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
33、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. Individual reprints (single
34、 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).4A research report is available from ASTM headquarters. RequestRR:D151010.FIG. 3 Time-Temperature Cooling Curves for Determining the Freezing Point of an Engine CoolantD1177073
