1、ASTM D2LbO 92 W 0759530 0505352 3 W Designation:D 2160-92 AMERICAN SOCIETY FOR lESTiNG AND MATERIALS 1916 Race St.Philadelphia,Pa 19103 Reprinted from the Annual Book of ASTM Standards.Copyright ASTM If not listed in the current combined index,will appear in ths next edition.An American National Sta
2、ndard Standard Test Method for Thermal Stability of Hydraulic Fluids This standard is issued under the fixed designation D 2160:the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indica
3、tes the year of last reapproval.A superscript epsilon(6)indicates an editorial change since the last revision or reapproval.1.scope 1.1 This test method covers the determination of the thermal stability of fluids.In this test method the volatile decomposition products are in continuous contact with
4、the fluid during the test.To eliminate possible catalytic metal effects,the fluid is confined in a glass apparatus.To remove the variable of oxidation,air is removed by vacuum prior to the initiation of the test.It must be remembered that this test method will not measure the thermal stability thres
5、hold(the temperature at which volatile oil fragments begin to form)but instead will indicate bulk fragmentation occurring at a specified temperature and testing period.(Warning:Explo-sion Hazard-Due to potential decomposition and genera-tion of high-pressure gas at 260 to 3 15C(500 to 6OO”F),this te
6、st method is not suitable for aqueous-base fluids or other fluids which generate high-pressure gas at these tempera-tures.)1.2 The values stated in Sl are the standard.1.3 This standard does not purport to address all of the safety problems,if any,associated with its use.It is the responsibility of
7、the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.For specific precautionary statements,see 6.1 and 8.9.2.Referenced Documents 2.1 ASTM Standards:D445 Test Method for Kinematic Viscosity of Trans-pa
8、rent and Opaque Liquids(and the Calculation of Dynamic Viscosity)2 D 664 Test Method for Acid Number of Petroleum Products by Potentiometric Titration2 D974 Test Method for Acid and Base Number by Color-Indicator Titration2 3.Terminology 3.1 Definition:3.1.1 thermal stability-the resistance to perma
9、nent changes in properties caused solely by heat.4.Summary of Test Method 4.1 The fluid is charged in a thermal stability test cell which is tightly sealed under vacuum to remove and pre-clude the presence of oxygen and water,The fluid is then.t This test method is under the jurisdiction of ASTM Com
10、mittee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcom-mittee D 02.N on Hydraulic Fluids.Current edition approved May 20,1992.Published July 1992.Originally published as D 2160-63.Last previous edition D 2160-RF.2 Attntral Book of ASTM Slandards,Vol 05.0 I.heated
11、at a given temperature and for a given period of time,and then examined for any physical or chemical changes.5.Significance and Use 5.1 This test method differentiates the relative stability of.hydraulic fluids at elevated temperatures in the absence of air and water under the conditions of the test
12、.Thermally unstable fluids form acidic contaminants which can cause hydraulic system malfunctions due to corrosion or change in viscosity of the fluid.The degree of correlation between this test and service performance at normal operating tempera-tures has not been determined.6.Apparatus 6.1 Test Ce
13、ll-The test cell shall be a glass tube,15 mm in inside diameter,20 mm in outside diameter,and 250 mm in length,3 with sufficient capacity to contain 20 ml of fluid and to permit heating and drawing the tube to a sealed end reasonably above the fluid level.A heavy-walled steel sample holdefl of prope
14、r size to contain the sealed glass tube also should be provided for safety reasons,6.2 Heating Bath-The bath shall be capable of being controlled within+-2.2”C(4F)at test temperatures of 260 and 316C(500 and 600F)and shall permit complete immersion of the test cell.The temperature gradient between f
15、luid sample and the heating bath should be kept at a minimum(less than 1C is recommended).An aluminum-block type bath is recommended for safety.The design of the apparatus shall be such as to permit the test fluid to reach the desired temperature within 15 min after insertion into the bath.7.Prepara
16、tion of Apparatus 7.1 Cleaning Test Cell-Since each test will necessitate a new test cell,cleaning is relatively simple.Scrubbing the new test cell with a suitable detergent,followed by a distilled water rinse and thorough drying,is sufficient.8.Procedure 8.1 Adjust the heating bath to the proper test temperature.8.2 Filter5 a portion of the fluid sample through a filter to remove particle contaminants.s A borosilicate glass combustion tube with closed end construction has been found satisfactor