1、Designation: D6138 16Standard Test Method forDetermination of Corrosion-Preventive Properties ofLubricating Greases Under Dynamic Wet Conditions (EmcorTest)1This standard is issued under the fixed designation D6138; the number immediately following the designation indicates the year oforiginal adopt
2、ion 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. Scope*1.1 This test method covers the determination of corrosion-preventive proper
3、ties of greases using grease-lubricated ballbearings under dynamic wet conditions.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wi
4、th 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:2D217 Test Methods for Cone Penetration of LubricatingGreaseD665 Te
5、st Method for Rust-Preventing Characteristics ofInhibited Mineral Oil in the Presence of WaterD1193 Specification for Reagent Water2.2 ISO Standards:3ISO 15 Rolling BearingsRadial BearingsBoundaryDimensionsGeneral PlanISO 3696 Water for Analytical Laboratory UseSpecifications and Test MethodsISO 712
6、0 Petroleum Products and LubricantsPetroleumOils and Other FluidsDetermination of Rust-preventingCharacteristics in the Presence of Water3. Terminology3.1 Definitions:3.1.1 lubricating grease, na semifluid to solid product ofa thickener in a liquid lubricant.3.1.1.1 DiscussionThe dispersion of the t
7、hickener forms atwo-phase system and immobilizes the liquid lubricant bysurface tension and other physical forces. Other ingredients arecommonly included to impart special properties. D2173.1.2 thickener, nin lubricating grease, a substance com-posed of finely-divided particles dispersed in a liquid
8、 lubricantto form the products structure.3.1.2.1 DiscussionThe thickeners can be fibers (such asvarious metallic soaps) or plates or spheres (such as certainnon-soap thickener), which are insoluble or, at most, only veryslightly soluble in the liquid lubricant. The general require-ments are that the
9、 solid particles be extremely small, uniformlydispersed, and capable of forming a relatively stable, gel-likestructure with the liquid lubricant. D2173.2 Definitions of Terms Specific to This Standard:3.2.1 corrosion, nreddish rust or black spots on the race.3.2.1.1 DiscussionAny stain through which
10、 the underly-ing metal surface is still visible shall be ignored.4. Summary of Test Method4.1 New, cleaned, and lubricated bearings are tested par-tially immersed in water (distilled, synthetic sea water, orsodium chloride solution) under no applied load at a speed of83 r min 6 5 r min in a predeter
11、mined sequence of runningand stopping for a period of approximately one week. Aftercleaning, the bearing rings are examined and rated according tothe degree of corrosion.5. Significance and Use5.1 This test method is used to assess the ability of grease toprevent corrosion in rolling bearings operat
12、ed in the presenceof distilled water, sodium chloride solution, or synthetic seawater. It is used for development and specification purposes.6. Apparatus6.1 Test BearingsUse a double row self-aligning ballbearing (30 mm by 72 mm by 19 mm), conforming to 1306 K1This test method is under the jurisdict
13、ion of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.G0.06 on Functional Tests - Contamination.Current edition approved April 1, 2016. Published May 2016. Originallyapproved in 1997. Last previous edition approved in 2013 as
14、 D6138 13. DOI:10.1520/D6138-16.2For 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.3Available from American Nati
15、onal Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1of ISO 15, with a steel
16、 cage.4In cases of dispute, the SKFbearing specified in Footnote 5 shall be used as the refereebearing.6.2 SKF TMG/Emcor Test Machine, see Annex A1 fordescription.6.3 Dentists Mirror, non-magnifying.6.4 Graduated Pipette or Syringe, capable of measuring20 mL 6 1 mL water.6.5 Oven, capable of maintai
17、ning 90 C 6 2 C.7. Reagents7.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are
18、available.5Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.7.2 Purity of WaterUnless otherwise indicated, referencesto water shall be understood to mean freshly boiled double
19、distilled water, water conforming to Specification D1193 TypeII, or reagent water as defined by Grade 2 of ISO 3696.7.3 Synthetic Sea WaterIf required, as specified in Speci-fication D665, and ISO 7120.7.4 Sodium Chloride Solutiona 0.5 mol L solution ofsodium chloride prepared using freshly boiled d
20、ouble distilledwater, water conforming to Specification D1193 Type II, orwater conforming to Grade 2 of ISO 3696, at a pH of 8.0 to 8.2adjusted by titration with sodium hydroxide solution.NOTE 1Other water types, such as that specified in SpecificationD1193, Type III, or other salt solutions and sal
21、t concentrations can be usedin this test method, although the precision when using other water typesand salt solutions has not been determined. It is recommended that the pHof the other water types is determined before use.7.5 Isopropyl Alcohol(WarningFlammable. Poison.Causes burns. Vapor extremely
22、irritating. May be fatal ifswallowed. Harmful if inhaled.)7.6 Ammonium Hydroxide(WarningFlammable. Poi-son. Causes burns. Vapor extremely irritating. May be fatal ifswallowed. Harmful if inhaled.)7.7 Solvent Rinse Solution, of the following composition byvolume:7.7.1 90 % Isopropyl alcohol.7.7.2 9 %
23、 Distilled water.7.7.3 1 % Ammonium hydroxide, 3.2 mol L concentration.(WarningFlammable. Poison. Causes burns. Vapor ex-tremely irritating. May be fatal if swallowed. Harmful ifinhaled.)7.8 Mineral Spirit, also known as Stoddard Solvent, reagentgrade. (WarningCombustible. Vapor Harmful.)8. Preparat
24、ion of Bearings8.1 Examine the test bearings carefully and select onlybearings that have outer rings and balls entirely free ofcorrosion. During the bearing preparation, handle the bearingswith tongs or protective gloves. Do not touch the bearings withbare fingers at any time. Use two new bearings f
25、or each greasebeing tested.8.2 Number bearings on the outside diameter of the outerring, but do not use chemical etching. One method to numberthe bearings is with an electric pen, which should be groundedon the outer ring surface being marked.8.3 Wash the selected bearings thoroughly in hot (50 C to
26、65 C) mineral spirits (Warningsee 7.8) to remove the rustpreventive. To ensure complete removal, subject the bearing toa second wash in fresh hot mineral spirits. (WarningThewashing temperatures specified are considerably above theflash point of the solvent. Accordingly, the washing operationshould
27、be carried out in a well-ventilated hood where noignition source is present.)NOTE 2The purpose of the two washes with hot mineral spirits in 8.3is to completely remove the rust preventative applied to the bearings forstorage. The duration of the washes required to remove this preventativewill be dep
28、endent on the equipment used by the lab and the type andamount of rust preventative applied by the bearing manufacturer. It isrecommended to visually inspect each bearing to assure the rust preven-tative is removed before proceeding to 8.4. If rust preventative is stillpresent after two washes, the
29、bearings should be washed again in the hotmineral spirits until the bearings are clean and free of residue.8.4 Transfer bearings to the solvent rinse solution(Warningsee 7.7.3) to remove any mineral spirits whichmay be present. Rinse each bearing and slowly rotate one ringrelative to the other ring
30、in fresh hot (65 C 65 C) solventrinse solution. Fresh rinse solution is used to avoid theselective evaporation of the components at the rinse tempera-ture.NOTE 3Care must be taken when handling bearings in the hot rinsesolution to avoid burns. Tongs and heat resistant gloves are recommended.8.5 Remo
31、ve each bearing from the solvent rinse solutionand place on filter paper to drain. After draining, dry thebearing in an oven at 90 C 6 2 C for 15 min to 30 min.8.6 Permit the bearing to cool to room temperature andreexamine the surfaces to ensure that corrosion-free bearingshave been selected. (Exer
32、cise care when handling the bearingto avoid rotating one ring relative to the other ring aftercleaning and drying.)8.6.1 Inspect the outer ring tracks. (Fig. 1 illustrates the areato be inspected.) If etch spots or corrosion are evident, rejectthe bearing. A dentists mirror can be helpful for inspec
33、tionpurposes.41306 K steel caged bearing manufactured by NTN and DKF may be used;however, precision had only been evaluated using SKF 1306 K/236 725 bearings.5Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reag
34、ents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeil Convention, Inc. (USPC), Rockville,MD.D6138 1629. Procedure9.1 Prepare the apparatus by removing a
35、ll traces of greasefrom the previous tests by wiping the plummer blocks. Washthe plummer blocks with the solvent rinse solution followed bywater. Dry thoroughly using a lint-free cloth.9.2 Distribute 10 g 6 0.1 g of the grease evenly in each testbearing using a spatula or bearing packer. Take care t
36、o avoidthe inclusion of air bubbles. Rotate the outer ring slightly witha gloved hand to assist distribution. Smear all the externalsurfaces of the bearing with additional grease.9.3 Prepare two bearings for each grease to be tested. Eachpair of bearings is used for one test.9.4 Place the adapter sl
37、eeves, bearings, and V-ring seals inposition on the shaft and finger-tighten the sleeve nuts.9.5 Place the shaft complete with greased bearings inposition in the test rig, taking care that the bearings arecentered in the plummer blocks.9.6 Place the top halves of the plummer block in positionand fin
38、ger-tighten the locking screws.9.7 Press the V-ring seals up against the plummer blocksusing the special tool supplied with the test machine.9.8 Run the test rig for 30 min 6 5 min at 83 r min 65 r min immediately after assembly to distribute the greaseevenly.9.9 Without delay, remove the top halves
39、 of the plummerblocks and introduce 10 mL of distilled water, synthetic seawater or sodium chloride solution into each side of eachplummer block (a total of 20 mL 6 1 mL) using a pipette orsyringe. Refit top halves of plummer blocks and finger-tightenthe locking screws.NOTE 4Although the test can be
40、 run with other user-defined solutions,the precision limits described in Section 12 apply only to tests conductedwith reagents described in Section 7.9.10 Without delay, operate the test rig according to thefollowing schedule:9.10.1 Run 8 h 6 10 min, stop, allow to stand 16 h 610 min;9.10.2 Run 8 h
41、6 10 min, stop, allow to stand 16 h 610 min;9.10.3 Run 8 h 6 10 min, stop, allow to stand 108 h 6 2h.9.11 Immediately following the time schedule (9.10), re-move the top halves of the plummer blocks. Lift the shaft andbearings on to a suitable support on the work bench. Unscrewthe sleeve nuts one or
42、 two revolutions. Tap the bearings lightlyto free them, then pull bearings, sleeves, and seals off the shaft.9.12 Dismantle the bearings for inspection by prying ballsout of the cage pockets until the outer ring can be removed.9.13 Wash the outer rings in the solvent rinse solution anddry, using a l
43、int-free cloth. Examine immediately.10. Rating Procedure10.1 Visually examine the outer ring track area for rust oretch spots, without the aid of any optical adjuncts, and evaluateas described in Table 1. Fig. 1 illustrates the area to beexamined. Fig. 2 illustrates examples intended to assist in th
44、eassessment of the degree of corrosion. Ignore any stainingthrough which the underlying metal surface is clearly visible.11. Report11.1 Report the degree of corrosion and the type of watersolution used for the test in accordance with one of theclassifications and descriptions in Table 1. If the two
45、ratingsagree within the precision given for repeatability, report thetwo figures, otherwise make two further determinations.NOTE 5To assist in estimating percentage corrosion area, a transpar-ent grid divided into suitable squares can be used.12. Precision and Bias12.1 PrecisionThe precision of this
46、 test method, as deter-mined by statistical examination of interlaboratory results, is asfollows:12.1.1 RepeatabilityThe difference between successivetest results, obtained by the same operator with the sameapparatus under constant operating conditions on identical testmaterial, in the normal and co
47、rrect operation of the testmethod, would exceed the values shown in Table 2 only in onecase in twenty.12.1.2 ReproducibilityThe difference between two singleand independent results, obtained by different operators work-ing in different laboratories on nominally identical testFIG. 1 Partial Outer Rin
48、g of Double-Row Self-Aligning BearingTABLE 1 Corrosion ClassificationsNOTE 1Under certain circumstances a pair of parallel bands may beobserved, the color of which changes with viewing angle; do not confusethese bands with corrosion which appears black when viewed from allangles.Rating Designation D
49、escription0 no corrosion no corrosion1 trace no more than three spots of corrosion,none of which has a diameter largerthan1mm2 light small areas of corrosion covering up to1 % of the surface3 moderate areas of corrosion covering between1 % and 5 % of the surface4 heavy areas of corrosion covering between5 % and 10 % of the surface5 severe areas of corrosion covering more than10 % of the surfaceD6138 163material, in the normal and correct operation of the testmethod, would exceed the values shown in Table 2 only in onecase in twe
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