1、Designation: D 6351 99 (Reapproved 2005)An American National StandardStandard Test Method forDetermination of Low Temperature Fluidity and Appearanceof Hydraulic Fluids1This standard is issued under the fixed designation D 6351; the number immediately following the designation indicates the year ofo
2、riginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the fluidity and appearance ofhydra
3、ulic fluids after storage at low temperature.1.2 This standard does not purport 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 and health practices and determine the applica-bility of regula
4、tory limitations prior to use. For specific hazardstatements, see Section 6.2. Referenced Documents2.1 ASTM Standards:2D97 Test Method for Pour Point of Petroleum ProductsD 2500 Test Method for Cloud Point of Petroleum ProductsD 6080 Practice for Defining the Viscosity Characteristicsof Hydraulic Fl
5、uidsE1 Specification for ASTM Liquid-in-Glass Thermometers3. Summary of Test Method3.1 After preliminary drying to remove trace amounts ofwater, the sample is cooled to a specified temperature. Afterseven consecutive days, the sample is examined for its abilityto flow and observed for homogeneity.4.
6、 Significance and Use4.1 The temperature at which a lubricant remains fluid andhomogeneous after seven days is an index of its ability towithstand prolonged exposure to cold temperature. With veg-etable oils and some synthetic esters, it is necessary to doextended cold storage testing. Quick cool, s
7、hort-term tests,such as Test Methods D97 and D 2500, do not adequatelypredict the tendency to solidify over longer time spans at coldtemperatures.4.2 This test method is not intended to indicate coldtemperature pumpability performance. A separate assessmentof viscometric performance should be made i
8、n order to assesscold flow properties, which are important in order to avoidsystem damage in cold temperature applications. Suitableguidelines for such testing and test temperatures for variousviscosity grades can be found in Practice D 6080.4.3 No specific temperature of measurement is given in thi
9、stest method because fluids with different viscosity grades havedifferent cold temperature performance expectations. For guid-ance on temperature selection relative to an intended lowtemperature viscosity grade or ISO VG, consult PracticeD 6080. As an example of using Practice D 6080, a L22viscosity
10、 grade would be evaluated at the lowest temperaturefor that grade, namely -22.9C. Alternatively, a fluid can beevaluated at the lowest temperature expected for field service.5. Apparatus5.1 Test Jar, cylindrical, of clear glass, flat bottom, 115 to125 mm in height. The inside diameter of the jar can
11、 rangefrom 30.0 to 32.4 mm, with a wall thickness of 1.6 mmmaximum. The jar shall have a line to indicate a sample height54 6 3 mm above the inside bottom.5.2 Thermometers, having ranges shown below and con-forming to the requirements prescribed in Specification E1.Thermometer TemperatureRangeThermo
12、meter NumberASTM IPHigh cloud and pour -38 to +50C 5C 1CLow cloud and pour -80 to +20C 6C 2CMelting Point +32 to 127C 61C 63C5.2.1 Since separation of liquid column thermometers occa-sionally occurs, thermometers should be checked visuallyimmediately prior to the test.5.3 Cork, to fit the test jar.1
13、This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.N0 on Hydraulic Fluids.Current edition approved May 1, 2005. Published June 2005. Originallyapproved in 1999. Last previous edition approved in 199
14、9 as D 635199.2For 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.1Copyright ASTM International, 100 Barr Harbor
15、Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.4 Bath, either an air or liquid bath maintained at theprescribed temperature with a firm support to hold the samplejars vertical. The required bath temperature shall be maintainedby refrigeration to within 61C of the prescribed te
16、mperature.6. Reagents and Materials6.1 Liquid for temperature reference jar. The followingmaterials are examples of suitable media that remain clearliquids at low temperature and in which the thermometer canbe placed.6.1.1 2 cSt Polyalphaolefin.6.1.2 Alcohol, Ethanol. (WarningFlammable.)7. Procedure
17、7.1 Pour the specimen into the test jar to the level mark.7.2 To remove trace amounts of water, preheat the sample to100C for 30 min, then cover loosely and allow the sample tocool for 30 min. If the hydraulic fluid is water based, forexample a water-glycol fluid, this drying step is to be omitted.7
18、.3 Close the test jar with the cork.7.4 Prepare a temperature reference jar in accordance with7.1 with a liquid that will remain fluid at the selected testtemperature. Insert a thermometer through a centrally boredcork so that it fits tightly and is coaxial and the bulb isimmersed so that the beginn
19、ing of the capillary is 3 mm belowthe surface of the liquid.7.5 Place the test jar and temperature reference jar in thebath. Be sure the sample is totally immersed in the coolingbath, paying particular attention if a liquid bath is used.7.6 Keep the samples in the bath for 168 consecutive h.7.7 Reco
20、rd the temperature of the thermometer in thereference jar prepared in accordance with 7.4 just beforeexamining the samples per 7.8.7.8 After 168 h, immediately examine the samples. Hold thejar in a horizontal position for 5 s and observe whether thesample flows. Note the presence of any crystals, pa
21、rticles, orseparation and the appearance of the specimen.8. Report8.1 Report the fluidity and condition of the sample at theend of the test period as follows:8.1.1 If the sample flows under the condition in 7.8, reportfluidity as: Fluid at (temperature of test).8.1.2 If the sample does not flow unde
22、r the conditions in 7.8,report fluidity as: Not fluid at (temperature of test).8.1.3 Report the presence of any crystals or particles in thesample or separation of the sample.8.1.4 Report the appearance of the sample at the testtemperature as: Clear, Haze Present,orOpaque.9. Precision and Bias9.1 No
23、 statement can be made yet about the precision of thistest method for measuring the fluidity or particle formingtendency of a lubricant specimen since a round robin iscurrently being conducted.9.2 There are no criteria for measuring bias in these test-product combinations, so no statement of bias ca
24、n be made.10. Keywords10.1 hydraulic fluid; low temperature appearance; low tem-perature fluidity; vegetable oilASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advis
25、ed that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either r
26、eapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If
27、you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 6351 99 (2005)2
