1、Designation:D743708(Reapproved 2019)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 year of
2、 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 water onthe
3、stability of engine coolants at elevated temperatures undercontrolled laboratory conditions.1.2 The values stated in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.1.3 This standard does not purpo
4、rt to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.4 This international standard was
5、developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Doc
6、uments2.1 ASTM Standards:2D1193 Specification for Reagent WaterD1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants orAntirusts for Testing PurposesE288 Specification for Laboratory Glass Volumetric Flasks2.2 British Standards:3BS 5117-1.5:1992 Coolant Hard Water Stability
7、 TestBSI BS ISO 5725-2 Accuracy(Trueness and Precision)ofMeasurement 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 60 C ina controlled oven f
8、or 14 days and then cooled to roomtemperature and inspected.Synthetic hard water is then addedand the test solution is returned to an oven set at 90 C for 14days.At the end of this period,the test engine coolant solutionis removed,cooled,and inspected.The cooled sample iscentrifuged and any precipit
9、ate treated with methanol.Thevolume of any precipitate left after 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 m
10、ightsimulate the conditions that a product would be subjected 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 lab
11、oratory method totest the sensitivity of the engine coolant to hard water.5.Apparatus5.1 Graduated Cylinder,of 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 2 C and 90 6 2 C.
12、5.4 Centrifugecapable of generating a relative centrifugalforce of 900.Relative centrifugal force5v/1335!2d(1)where:v=rotational velocity(r/min)and,d=diamter(mm)between the ends of the centrifuge tubes atthe point of maximum swing.5.5 Pipette,of capacity 20 6 0.50 mL.5.6 Volumetric Balance,one-mark,
13、1000 mL(compliantwith Specification E288,Class B requirements).1This test method 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 Oct.1,2019.Published Oc
14、tober 2019.Originallyapproved in 2008.Last previous edition approved in 2013 as D743708(2013).DOI:10.1520/D743708R19.2For 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
15、standards Document Summary page onthe ASTM website.3Available from British Standards Institution(BSI),389 Chiswick High Rd.,London W4 4AL,U.K.,http:/.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed
16、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 Organization Technical Barriers to Trade(TBT)Committee.1 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
