1、Designation: D1177 12D1177 16Standard Test Method forFreezing Point of Aqueous Engine Coolants1This standard is issued under the fixed designation D1177; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、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 Defense.1. Scope*1.1 This test method covers the determination of the
3、 freezing point of an aqueous engine coolant solution in the laboratory.NOTE 1Where solutions of specific concentrations are to be tested, they shall be prepared from representative samples as directed in Practice D1176.Secondary phases separating on dilution need not be separated.NOTE 2These produc
4、ts may also be marketed in a ready-to-use form (prediluted).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 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is
5、the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D1176 Practice for Sampling and Preparing Aqueous Solutions of Engine Coolants or Antir
6、usts for Testing PurposesE1 Specification for ASTM Liquid-in-Glass Thermometers3. Terminology3.1 Definitions:3.1.1 freezing pointthe temperature at which crystallization begins in the absence of supercooling, or the maximumtemperature reached immediately after initial crystal formation in the case o
7、f supercooling, or the temperature at which solidcrystals, formed on cooling, disappear when the temperature of the specimen is allowed to rise.4. Summary of Test Method4.1 This test method involves the determination of the time-temperature curve prior to freezing and the determination of thehorizon
8、tal or flattened portion of the freezing curve. The freezing point is taken as the intersection of projections of the coolingcurve and the freezing curve. If the solution supercools, the freezing point is the maximum temperature reached after supercooling.5. Significance and Use5.1 The freezing poin
9、t of an engine coolant indicates the coolant freeze protection.5.2 The freezing point of an engine coolant may be used to determine the approximate glycol content, provided the glycol typeis known.6. Apparatus6.1 Freezing Point Apparatus, shown assembled in Fig. 1, consisting of the following:6.1.1
10、Cooling Bath, in which the refrigerant is contained, consisting of a standard 1.9-L (2-qt) Dewar flask. The flask may besilvered or unsilvered, and is supported in a close-fitting container.Apad of glass wool is placed in the bottom of the flask to protectit from damage by tip of freezing tube.1 Thi
11、s test method is under the jurisdiction of ASTM Committee D15 on Engine Coolants and Related Fluids and is the direct responsibility of Subcommittee D15.03 onPhysical Properties.Current edition approved Oct. 1, 2012April 1, 2016. Published November 2012May 2016. Originally approved in 1951. Last pre
12、vious edition approved in 20072012 asD1177 07.D1177 12. DOI: 10.1520/D1177-12.10.1520/D1177-16.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document
13、 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 been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recom
14、mends 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 document.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C70
15、0, West Conshohocken, PA 19428-2959. United States16.1.2 Freezing Tube3 consisting consisting of a 200-mL (6.8-oz.) unevacuated, unsilvered Dewar flask. The tube is closed bya cork having a central hole for the thermocouple or resistance thermometer, a second hole placed to one side for passage of t
16、hestirring rod, and a third hole for introducing wire for seeding at appropriate time.6.1.3 Stirring Mechanism, consisting of a five-coil stirrer formed of stainless steel wire 1.6 mm (116 in.) in diameter. The coilsare so spaced that, in the extreme upward position during operation, no coils are ex
17、posed above the surface of the sample. Thestirrer is agitated by means of an ordinary windshield wiper motor or other motor devices, operating through suitable linkages soas to provide linear motion of the stirrer. The length of the stroke is adjusted so that the coil just clears the bottom of thefr
18、eezing-point tube at low point of the stroke.6.1.4 Temperature MeasurementA resistance thermometer or a multi-junction copper-constantan thermocouple may be usedwith suitable measuring instruments, providing these give an over-all sensitivity of 0.1C (0.2F). The instrument shall becalibrated before
19、each series of determinations by using suitable reference standards. Platinum resistance thermometers have beenadopted as a standard by the National Institute of Standards and Technology (NIST) and are recommended for this standard.NOTE 3ASTM Coolant Freezing Point Temperature Measuring Instruments
20、having a range from 37 to + 2C (35 to + 35F) or 54 to 15C(65 to + 5F) and conforming to the requirements for Thermometers 75F or 76F as prescribed in SpecificationsSpecification E1, may be used where lessaccuracy is acceptable provided reference standards are used for calibration purposes.7. Refrige
21、rant7.1 The refrigerant shall consist of solid carbon dioxide in alcohol or in other suitable bath liquids.NOTE 4A layer of dry ice, at least 13 mm (12 in.) thick, must be maintained in the bottom or on the top of the cooling bath during a determination,depending on the bath liquid used. Adequate pr
22、ecautions should be taken against fire hazards or toxic effects of bath liquids, or both.3 For 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 Engine Antifreeze,”in the February 1951 issue of the ASTM Bulle
23、tin may be used.FIG. 1 Assembly of Freezing Point ApparatusD1177 1627.2 Liquid nitrogen may be used as the refrigerant when the freezing point of the coolant is 46C (50F) or lower.(WarningThe liquid nitrogen should be discarded after each days use to avoid the possibility of explosion due to dissolv
24、edoxygen and inadvertent mixing with organic coolant materials.Warning)The liquid nitrogen should be discarded after each daysuse to avoid the possibility of explosion due to dissolved oxygen and inadvertent mixing with organic coolant materials.)8. Procedure8.1 Assemble the apparatus as shown in Fi
25、g. 1, with no refrigerant and no sample of coolant yet in place. Check the operationof the stirring mechanism after assembly to be sure that all parts operate freely.8.2 Fill the Dewar flask surrounding the freezing tube with the refrigerant liquid, adding pieces of solid carbon dioxide fromtime to
26、time to maintain conditions mentioned in Note 4. Temporarily remove the stopper from the freezing tube and introduce75 to 100 mL (2.65 to 3.4 oz.) of the sample.NOTE 5The sample may be precooled to approximately 8C (15F) above the expected freezing point before introducing it into the freezing tube.
27、8.3 Start the stirrer and adjust it to operate at 60 to 80 strokes per min (Note 6).As soon as stirring is begun, observe and recordthe temperature at regular intervals of time. Electronic data acquisition systems may also be used in place of manual observationand recording. As the expected freezing
28、 point is approached, the time intervals shouldshall be quite short, 15 s if possible. 10 to15 s. At the expected freezing point, seeding shouldshall be started to prevent supercooling. This canshall be accomplished byintroducing a wire which has a small portion of the solution being tested frozen o
29、n its tip. It is most convenient to freeze thissolution in a small test tube inserted directly into the cooling bath. The cooling rate shall be less than 1C (2F)/min at the timethe solution is seeded.NOTE 6A stroke is considered as a complete cycle of one upward and one downward motion of the stirre
30、r.NOTE 7The cooling rate must be less than 1C (2F)/min at the time the solution is seeded.8.4 Continue temperature readings at regular intervals for at least 10 min after the apparent freezing point.9. Report9.1 Plot the observed temperature against time on rectangular coordinate paper. Where the cu
31、rve shows a definite flat or plateauduring freezing, the freezing point is taken as the intersection of projections of the cooling curve and the flat or horizontal plateauportion of the freezing curve (see Report the following information:Fig. 2(a). If the solution supercools, the freezing point is
32、themaximum temperature reached immediately after supercooling (see Fig. 2(b).NOTE 8The amount of supercooling should be held to a minimum. If the supercooling exceeds 1C (2F) the test should be rejected.9.1.1 If the temperature-measuring instrument does not automatically plot temperature versus time
33、, manually plot the observedtemperature against time on rectangular coordinate paper. Where the curve shows a definite flat or plateau during freezing, thefreezing point is taken as the intersection of projections of the cooling curve and the flat or horizontal plateau portion of thefreezing curve (
34、see Fig. 2(a). If the solution supercools, the freezing point is the maximum temperature reached immediately aftersupercooling (see Fig. 2(b).NOTE 7The amount of supercooling should be held to a minimum. If the supercooling exceeds 1C (2F) the test should be rejected.FIG. 2 Time-Temperature Cooling
35、Curves for Determining the Freezing Point of an Engine CoolantD1177 16310. 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 Laboratorie
36、s 1.30 2.3411. Keywords11.1 aqueous engine coolants; engine coolants; engine coolants; freezing pointSUMMARY OF CHANGESSubcommittee D15.03 has identified the location of the selected changes to this standard since the last issue(D1177-07)(D1177-12) that may impact the use of this standard.(1) The wo
37、rd “resistance” was added before “thermometer” in 6.1.2.(2) Updated Mandatory language was added in 8.3.(3) ModifiedNote Fig. 17, which contains mandatory language, was deleted and the sentence was moved to 8.3.(4) Removed Fig. 2.The first sentence of 9.1.1 was revised.ASTM International takes no po
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