1、Designation: D7820 12Standard Test Method forEngine Coolant Corrosion Protection Under AcceleratedThermal and Oxidizing Conditions Using a RotatingPressure Vessel1This standard is issued under the fixed designation D7820; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, the year 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 determination of engine coolantcorrosion pr
3、otection and stability under accelerated thermaland oxidizing conditions using a rotary pressure vessel.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. Specific hazardstatements are given in 6.2, 6.3, 6.4, 6.5, 6.7, 6.8, 6.9, 6.10,11.1,
5、12.8, 12.9, and 12.10.2. Referenced Documents2.1 ASTM Standards:2B32 Specification for Solder MetalD1176 Practice for Sampling and Preparing Aqueous Solu-tions of Engine Coolants or Antirusts for Testing PurposesD1193 Specification for Reagent WaterD1384 Test Method for Corrosion Test for Engine Coo
6、lantsin GlasswareD2272 Test Method for Oxidation Stability of Steam Tur-bine Oils by Rotating Pressure VesselE1 Specification for ASTM Liquid-in-Glass ThermometersE230 Specification and Temperature-Electromotive Force(EMF) Tables for Standardized Thermocouples3. Summary of Test Method3.1 The engine
7、coolant test fluid and a metal coupon bundleare placed in a covered glassware container in a pressure vesselequipped with a pressure gauge. The pressure vessel is chargedwith air or oxygen to a gage pressure of 620 kPa (90 psi, 6.2bar) (see conversion factor 1), placed in a constanttempera-ture oil
8、bath set at a controlled temperature (typically 115C(239F) or 150C (302F) and rotated axially at 100 rpm at anangle of 30 from horizontal for 168 h. The use of air oroxygen and test temperature is left to the discretion of the userof the test. Engine coolant performance is assessed for corro-sion pr
9、otection based on changes in metal coupon weights andcoolant stability is evaluated based on changes in coolantphysical and compositional properties. The test method isbased on a combination of ASTM D1384 (modified metalcoupon bundle) and ASTM D2272 (glassware, pressure vessel,and bath apparatus) te
10、st procedures.100 kPa 5 1.00 bar 5 14.5 psi (1)4. Significance and Use4.1 Engines operating under severe conditions involvinghigh temperatures, hot spot areas, entrained air, and/or smallcooling systems are placing greater emphasis on engine coolantoxidation stability and corrosion protection. This
11、standardprovides an accelerated test method to assess engine coolantperformance under high temperature oxidizing test conditionsof new, used, and/or recycled engine coolants. The test methodmay also serve as a screening tool to determine oxidationstability. The test results of this method cannot sta
12、nd alone asevidence of satisfactory oxidation stability and corrosionprotection. The actual service of an engine coolant formulationcan be determined only by more comprehensive bench,dynamometer, and field tests.5. Apparatus5.1 Oxidation Vessel, Glass Sample Container with Four-Hole Polytetrafluoroe
13、thylene (PTFE) Disk, Hold-DownSpring, Pressure Gage, and Test Bath, as described in AnnexA1. The assembled apparatus is shown schematically in Fig. 1and Fig. A1.5.5.2 Temperature-Measuring Instrument (EnvironmentallySafe Thermometer or Thermocouple)An ASTM partial im-mersion temperature-measuring in
14、strument having a rangefrom 20 to 150C (0 to 302F) and conforming to the1This test method is under the jurisdiction of ASTM Committee D15 on EngineCoolants and Related Fluids and is the direct responsibility of SubcommitteeD15.21 on Extended Life Coolants.Current edition approved Nov. 1, 2012. Publi
15、shed December 2012. DOI:10.1520/D7820-12.2For 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.Copyright ASTM Inter
16、national, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1requirements for Thermometer 1C (1F), as prescribed inSpecification E1 or thermocouple as summarized in Specifica-tion E230.6. Reagents and Materials6.1 Purity of ReagentsReagent-grade chemicals shall beuse
17、d in all tests. Unless otherwise specified, it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.3Other grades may be usedprovided it is first ascertained that the reagent is of su
18、fficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.6.2 Acetone, reagent grade. (WarningFlammable, healthhazard.)6.3 Glacial Acetic Acid Concentrate, reagent grade(WarningAvoid contact with skin and eyes. Handle in afume hood.)6.4 Hydrochloric Acid, concentrate
19、d HCl (specific gravity(sp gr) 1.19) (WarningHCl is a strong acid. Avoid contactwith skin and eyes. Handle in a fume hood.)6.5 Isopropyl Alcohol, reagent grade. (WarningFlammable, health hazard.)6.6 Liquid Detergent.6.7 n-Heptane, 99.0 minimum mol% (pure grade).(WarningFlammable, health hazard.)6.8
20、Nitric Acid, HNO370% mass (WarningHNO3 is astrong toxic oxidant and acid. Avoid contact with skin, eyes,and clothing. Do not breathe vapor. Handle in a fume hood.)6.9 Oxygen, 99.5 % with pressure regulation to 620 kPa (90psi, 6.2 bar). (WarningVigorously accelerates combustion.)6.10 Potassium Hydrox
21、ide, Alcohol Solution (1 mass %)Dissolve 12 g of potassium hydroxide (KOH) pellets in 1 L ofthe isopropyl alcohol. (WarningFlammable, health hazard.)6.11 Silicone Stopcock Grease.7. Test SpecimensNOTE 1The specimens prescribed in this test method have beenaccepted by automobile manufacturers, but th
22、eir composition may not bethe same as that of alloys currently used for engine-cooling systemcomponents. Therefore, specimens other than those designated in this testmethod may be used by mutual agreement of the parties involved.7.1 TypeThe following metal test specimens,4representa-tive of cooling
23、system metals, shall be used.7.1.1 SteelUNS G10200 (SAE 10205) cut from 1.59-mm(116-in.) cold rolled sheet stock to size 50.8 by 25.4 mm (2 by1 in.). Chemical composition of the carbon steel is as follows:carbon, 0.17 to 0.23 %, manganese; 0.30 to 0.60 %;phosphorus, 0.04 % maximum; sulfur, 0.05 % ma
24、ximum.7.1.2 Copper, conforming to UNS C11000 (SAE CA110) orUNS C11300 (SAE CA113). Cold rolled and cut from1.59-mm (116-in) sheet stock to size 50.8 by 25.4 mm (2 by 1in.).7.1.3 Brass, conforming to Alloy UNS C26000 (SAE CA260). Half-hard, cut from 1.59-mm (116-in.) sheet stock to size50.8 by 25.4 m
25、m (2 by 1 in.).3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United St
26、ates Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.4Complete sets or individual metal test specimens are available from: (a) TheMetaspec Company, P.O. Box 27707, San Antonio, TX 78227; or ( b) AlabamaSpecialty Products, Inc., P.O. Box 8, Munford, AL 362
27、68.5UNIFIED Numbering System for Metals and Alloys, SAE-ASTM, July 1995.FIG. 1 Schematic Drawing of Rotary Pressure Vessel Test ApparatusD7820 1227.1.4 SolderAbrass specimen as described in 7.1.3 coatedwith solder conforming to Alloy Grade 30A (SAE 3A) ofSpecification B32.7.1.5 Cast Aluminum, confor
28、ming to alloy UNS A23190(SAE 329). Specimen size, 50.8 by 25.4 by 3.18 mm (2 by 1 by18 in.).7.1.6 Cast Iron, conforming to Alloy UNS F10007 (SAEG3500). Specimen size, 50.8 by 25.4 by 3.18 mm (2 by 1 by18in.).7.2 ArrangementSee Fig. 2.7.2.1 Metal Specimen ArrangementNone of the hardwareused in the me
29、tal specimen arrangement (metal specimen,screws, insulating spacers, insulating sleeves, and nuts) can bereused for a test. The metal test specimens shall be drilledthrough the center with a 6.75-mm (1764-in.) drill to accom-modate a 41.28-mm (158-in.) 10-24 brass machine screwcovered with a thin-wa
30、lled insulating sleeve. Polytetrafluoro-ethylene tubing with a 6.35-mm (14-in.) outside diameter,width of 1.59-mm (116-in.), and a wall thickness of 0.4 mm(164-in.) is satisfactory. Two PTFE legs shall be cut from1.59-mm (116 16-in.) PTFE sheet stock to size 50.80 by 28.58mm (2 by 118 in.). A 6.35-m
31、m (14-in.) diameter hole shall bedrilled in each leg with the hole centered between 22.22 and28.58 mm (78 and 118 in.) of the length and 14.28 mm (916 in.)from each side. The test “bundle” shall be made up on theinsulated screw with the specimens in the following order:PTFE leg, copper, solder, bras
32、s, steel, cast iron, cast aluminum,and PTFE leg. The specimens shall be separated by 3.18-mm(18-in.) insulating PTFE spacers having a 6.75-mm (1764-in.)inside diameter and a 11.11-mm (716-in.) outside diameter.Insulating spacers are not to be used between the PTE end legsand the copper and aluminum
33、metal specimens. The bundleshall be firmly tightened together with the bolt and nut. Inspectthe bundle to insure that there is not electrical connectionbetween the metal specimens, center bolt, and nut. Inspect thebundle also to ensure that the PTFE legs extend past the metalspecimens on the bottom
34、and sides to minimize etching of theborosilicate glass container by the metal specimen bundle.8. Preparation of Test Specimens8.1 Sand the cast iron and cast aluminum specimens on the25.4- by 50.8-mm (1- by 2-in.) cut surfaces with “coarse”grade (No. 1) emery cloth. Remove any burrs from couponedges
35、 and hole. Scrub all specimens vigorously using amoistened bristle brush and ground pumice powder or finesilicon carbide grit until the entire metal area is bright, shiny,and free from any visible oxide film or tarnish.8.2 Rinse the specimens thoroughly with tap water, thenrinse with acetone, dry, a
36、nd weigh to nearest 1 mg. Castaluminum specimens should be dried in a 100C (212F) ovenfor1htoaconstant weight before recording the weight.NOTE 2If the test specimens are not to be used immediately, keepthem in a desiccator until required.9. Test Solution9.1 Engine Coolant Test FluidThe engine coolan
37、t testfluid shall be prepared by mixing 50 vol % engine coolantconcentrate with 50 vol % ASTM D1193 Type IV reagentwater per ASTM D1176 preparation procedure. Pre-diluted /ready to use 50/50 coolants may also be used in this standard.9.2 The engine coolant test fluid shall be tested before andafter
38、the test for physical properties and chemical properties(water/glycol content and pH; corrosion inhibitors: boron,nitrite, nitrate, molybdenum, phosphate, silicate, azoles, andother organic additive technology inhibitors; corrosion metals:aluminum, copper, iron, lead, and zinc; and coolant oxidation
39、products: glycolates and formates).10. Test Conditions10.1 Engine Coolant Test FluidThe test shall be run on a55-mL sample of engine coolant test fluid per test.10.2 Test Gas and TemperatureThe test shall be con-ducted using either 1) air at 115C (239F) or 2) oxygen at150C (302F). The temperature sh
40、all be maintained at 62Cthroughout the test.FIG. 2 Test Specimens ArrangementD7820 12310.3 Rotary Pressure VesselThe rotary pressure vesselshall be charged with 620-kPa (90-psi) gas (oxygen or air) androtated in the bath at 100 rpm at a 30 angle from horizontal.10.4 Test DurationThe test shall be ru
41、n continuously forone week (168 h).11. Preparation of Apparatus11.1 Cleaning of Pressure VesselWash the pressure vesselbody, cap, and inside vessel stem with hot detergent solutionand rinse thoroughly with water. Rinse the inside of the stemwith isopropyl alcohol and blow dry with compressed air. If
42、 thevessel body, cap, or inside of the stem exhibit any oxidationproducts residue or noticeable sour odor (oxidization odor),after the simple cleaning, wash with 1 mass % alcoholic KOHsolution and repeat as before. Failure to remove oxidationresidue can adversely affect test results.11.2 Cleaning of
43、 Glass ContainerDrain and rinse with asuitable solvent (for example, n-heptane or acetone). Soak orscrub in an aqueous detergent solution. Brush thoroughly andflush thoroughly with tap water. Rinse with isopropyl alcohol,followed by distilled water, and air dry. If any insolublesremain, soak overnig
44、ht in a non-metal cleaning solution6andrepeat the above procedure starting from the tap water flush.11.3 Cleaning of PTFE Disks and End LegsRemove anyresidues from previous runs with a suitable solvent and cleanby brushing with a detergent solution. Rinse thoroughly withtap water, followed by distil
45、led water rinse, and air dry.12. Procedure12.1 ChargingPour 55- 6 0.5-mL engine coolant testfluid into the glass container and place the metal specimenbundle in the glassware container. Add 5 mL of ASTM D1193Type IV reagent water to the pressure vessel body and slide theglass container into the pres
46、sure vessel body (see Note 3).Cover the glass container with a 57.2-mm (214-in.) PTFE diskand place a hold-down spring on top of the PTFE disk. Applya thin coating of silicone stopcock grease or drop of ethyleneglycol to the O-ring vessel seal located in the gasket groove ofthe vessel cap to provide
47、 lubrication and insert the cap into thevessel body.NOTE 3The water between the vessel wall and the sample containeraids heat transfer.12.2 Tighten the closure ring by hand. Cover the threads ofthe gage-nipple with a thin coating of stopcock grease (PTFEpipe tape is a suitable alternative to the use
48、 of stopcock grease)and screw the gage into the top center of the vessel stem.Attach the oxygen or air line with an inline pressure gage to theinlet valve on the vessel stem. Slowly turn on the oxygen or airsupply valve until the pressure has reached 620 kPa (90 psi, 6.2bar). Turn off the gas supply
49、 valve. Slowly release pressure byloosening the fitting or by using an inline bleeder valve. Repeatpurging process two more times; the purge step should takeapproximately 3 min. Adjust the regulating valve on the gassupply tank to 620 kPa (90 psi, 6.2 bar) at a room temperatureof 25C (77F). For each 2.0C (3.6F) above or below thistemperature, 5 kPa (0.7 psi, 0.05 bar) shall be added orsubtracted to attain the required initial pressure. Fill the vesselto this required pressure and close the inlet valve securely byh
