1、Designation: D7437 08 (Reapproved 2013)Standard Test Method forTemperature and Hard Water Stability of Engine Coolants1This standard is issued under the fixed designation D7437; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear 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.1. Scope1.1 This test method covers a simple glassware-type proce-dure for evaluating the effects of temperature and hard w
3、ater onthe stability of engine coolants at elevated temperatures undercontrolled laboratory conditions.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,
4、 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.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1176 P
5、ractice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants or Antirusts for Testing PurposesE288 Specification for Laboratory Glass Volumetric Flasks2.2 British Standards:3BS 5117-1.5:1992 Coolant Hard Water Stability TestBSI BS ISO 5725-2 Accuracy (Trueness and Precision) ofMeasuremen
6、t Methods and ResultsPart 2: Basic Methodfor the Determination of Repeatability and Reproducibil-ity of a Standard Measurement Method3. Summary of Test Method3.1 A sample engine coolant concentrate is kept at 60C ina controlled oven for 14 days and then cooled to roomtemperature and inspected. Synth
7、etic hard water is then addedand the test solution is returned to an oven set at 90C for 14days. At the end of this period, the test engine coolant solutionis removed, cooled, and inspected. The cooled sample iscenrifuged and any precipitate treated with methanol. Thevolume of any precipitate left a
8、fter the methanol wash isdecanted is recorded.4. Significance and Use4.1 4.1 This test method provides information on the stabil-ity of the engine coolant concentrate when stored at elevatedtemperatures for two weeks. These test conditions mightsimulate the conditions that a product would be subject
9、ed to intransit and storage in warehouses before delivery to thecustomer.4.2 This test method provides information on the stability ofan engine coolant diluted with synthetic hard water at elevatedtemperatures. This test method provides a laboratory method totest the sensitivity of the engine coolan
10、t to hard water.5. Apparatus5.1 Graduated Cylinderof capacity 50 6 0.50 mL.5.2 Graduated Conical Centrifuge Tubes, of capacity 100mL with stoppers.5.3 Forced Ventilation Oven, capable of being maintained attemperatures of 60 6 2C and 90 6 2C.5.4 Centrifugecapable of generating a relative centrifugal
11、force of 900.Relative centrifugal force 5 v/1335!2d (1)where:v = rotational velocity (r/min) and,d = diamter (mm) between the ends of the centrifuge tubesat the point of maximum swing.5.5 Pipette, of capacity 20 6 0.50 mL.5.6 Volumetric Balance, one-mark, 1000 mL (compliantwith Specification E288, C
12、lass B requirements).6. Reagents and Materials6.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents conform to the specification of the Committee onAnalytical Reagents of the American Chemical Society where1This test meth
13、od is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Related Fluids and is the direct responsibility of SubcommitteeD15.06 on Glassware Performance Tests.Current edition approved May 1, 2013. Published June 2013. Originallyapproved in 2008. Last previous edition approved in 2008
14、as D7437-08. DOI:10.1520/D7437-08R13.2For 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 standards Document Summary page onthe ASTM website.3Orders for all British
15、Standards Institution (BSI) International and foreignstandards publications should be addressed to Customer Services, telephone:020-8996 9001 and fax: 020 8996 7001.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1such specifications a
16、re available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean reagent water as d
17、efinedby Type IV of Specification D1193.6.3 Synthetic Hard Water Stock SolutionPrepare a stocksolution by dissolving 44.10 g of calcium chloride dehydrate(CaCl22H2O) in water in a 1000-mL one-mark volumetricflask and diluting to the mark with water. Before use, dilute thisstock solution 1:50 with wa
18、ter.6.4 Methanol, CH3OH (WarningSee 7.1).7. Hazards7.1 MethanolPoison, extremely flammable, harmful ifswallowed or inhaled. Flash point of 12C.8. Sampling, Test Specimens and Test Units8.1 Take a representative sample of not less than 500 mL,preferably from previously unopened containers in which th
19、eproduct is normally offered for sale, in accordance withPractice D1176. Place the sample in clean, dry, stoppered glassbottles of a dark color. Take care to ensure that any methodused for sealing the sample does not cause contamination.9. Procedure9.1 Using a graduated 50-mL cylinder, measure 50 mL
20、 ofthe product into two clean, dry 100-mL centrifuge tubes.Record the appearance of the product (see Section 10). Stopperthe tubes and place them in the oven, maintained at 60 6 2C.After 14 days, remove the tubes and allow them to cool toroom temperature for 1 h.9.2 Inspect the cooled product and no
21、te any gelation orprecipitation (see Section 10).9.3 Prepare the synthetic hard water before use. Prepare bydiluting the hard water stock solution by adding 1:50 byvolume with water.9.4 Add 50 mL of the synthetic hard water to each tubecontaining product, restopper the centrifuge tubes, and mix bysh
22、aking. Record the appearance of the solution (see Section10). Place the tubes in the oven maintained at 90 6 2C. After14 days, remove the tubes and allow them to cool to roomtemperature and maintain at room temperature for 1 h.9.5 Inspect the cooled solution and note any gelation orprecipitation. Ce
23、ntrifuge the cooled solution, using a relativecentrifugal force of 900, for 15 min. Carefully decant the liquorfrom any precipitate present at the bottom of the centrifugetubes.9.6 Using the 20-mL pipette, add 20 mL of the methanol tothe precipitate in the centrifuge tubes and shake vigorouslyuntil
24、the precipitate is dislodged to ensure thorough washing.Recentrifuge for 15 min. Decant the methanol from anyprecipitate present at the bottom of the centrifuge tubes.9.7 Record the volume of any precipitate present (in mil-lilitres).10. Report10.1 The test report shall include the following informa
25、-tion: reference to this test method, complete identification ofthe product and its composition if known, and identificationnotation of the test and the dates the test was run.10.2 Elevated Temperature Storage Stability of the EngineCoolant ConcentrateGive a description of the samples be-fore and af
26、ter 14 days of storage at elevated temperature. Listany changes seen in the samples. Include: color change,whether any gelation or precipitation occurred, or any otherfeatures noted during the test.10.3 Elevated Temperature Storage Hard Water Stability ofthe Engine Coolant Solution:10.3.1 Give a des
27、cription of the samples before and after theaddition of the synthetic hard water and a description of thesamples after 14 days of storage at elevated temperature. Listany changes seen in the samples. Include: color change,whether any gelation or precipitation occurred, or any otherfeatures noted dur
28、ing the test.10.3.2 Give the individual and average volume of anyprecipitate present at the end of the test.11. Precision and Bias11.1 Precision:11.1.1 The repeatability standard deviation of the precipitatevolumes has been determined to be 0.08 mL. The repeatabilityand reproducibility of this test
29、method is being redeterminedand will be available on or before December 2012.NOTE 1The precision data were determined from an experimentconducted in 1990 involving six laboratories and three samples followingthe procedure outlined in BS 5117-1.5:1992, the test results beingsubjected to statistical a
30、nalysis as described in BSI BS ISO 5725-2.11.1.2 No precision information is provided about the otherproperties measured in this test method since the test results arenonquantitative.11.2 BiasNo precision information can be presented onthe bias of the procedures in this test method because theseprop
31、erties are defined in terms of this test method.12. Keywords12.1 antifreeze; elevated temperature; engine coolant; hardwater; stability4Reagent Chemicals, American Chemical Society Specifications , AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the
32、American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Dorset, U.K., and the United States Pharmacopeia andNational Formulary, U.S. Pharmacopeial Convention, Inc., (USPC), Rockville,MD.D7437 08 (2013)2ASTM International takes no position respecting the validity of any pat
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