1、Designation:D743708(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 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 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,assoc
4、iated 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 Practice for Samp
5、ling 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 TestBSI BS ISO 5725-2 Accuracy(Trueness and Precision)ofMeasurement Methods and Resul
6、tsPart 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.Synthetic hard water is the
7、n 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 after the methanol wash isdec
8、anted 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 subjected to intransit and storage in
9、 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 coolant to hard water.5.Apparatus5.1
10、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 centrifugalforce of 900.Relative centrifugal
11、force5v/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,Class B requirements).6.Reagents and Materials6.1 P
12、urity 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 method is under the jurisdiction of ASTM Committee D15 on
13、 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 as D7437-08.DOI:10.1520/D7437-08R13.2For referenced ASTM
14、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 Standards Institution(BSI)International and foreignstandards pu
15、blications 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 States1 such specifications are available.4Other grades may be used,provided it is first ascertained
16、 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 definedby 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 thisst