ASTM_D_1831_-_11.pdf

Designation:D183111Standard Test Method forRoll Stability of Lubricating Grease1This standard is issued under the fixed designation D1831;the number immediately following the designation indicates the year oforiginal 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.This standard has been approved for use by agencies of the U.S.Department of Defense.1.Scope1.1 This test method covers determination of the changes inthe consistency,as measured by cone penetration,of lubricat-ing greases when worked in the roll stability test apparatus.1.2 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.2.1 ExceptionThe values stated in inch-pound units forthe apparatus dimensions are to be regarded as standard;the SIconversions are provided for information only.1.3 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 regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D217 Test Methods for Cone Penetration of LubricatingGreaseD1403 Test Methods for Cone Penetration of LubricatingGrease Using One-Quarter and One-Half Scale ConeEquipmentD4175 Terminology Relating to Petroleum,PetroleumProducts,and Lubricants3.Terminology3.1 Definitions:3.1.1 consistency,nof lubricating grease,the degree ofresistance to movement under stress.3.1.1.1 DiscussionThe term consistency is used somewhatsynonymously with penetration.Generally,consistency refersto the worked penetration of a grease.D2173.1.2 lubricant,nany material interposed between twosurfaces that reduces the friction or wear between them.D41753.1.3 lubricating grease,na semi-fluid to solid product ofa dispersion of a thickener in a liquid lubricant.3.1.3.1 DiscussionThe dispersion of the thickener forms atwo-phase system and immobilizes the liquid lubricant bysurface tension and other physical forces.Other ingredientsimparting special properties are often included.D2173.1.4 penetration,nof lubricating grease,the depth thatthe standard cone,when released to fall under its own weightfor 5 s,enters the sample.D2173.1.5 thickener,nin lubricating grease,a substance com-posed of finely divided particles dispersed in a liquid lubricantto form the products structure.3.1.5.1 DiscussionThe thickener can be fibers(such asvarious metallic soaps)or plates or spheres(such as certainnon-soap thickeners)which are insoluble or,at the most,onlyvery slightly soluble in the liquid lubricant.The generalrequirements are that the solid particles be extremely small,uniformly dispersed,and capable of forming a relatively stable,gel-like structure with the liquid lubricant.D2173.1.6 worked penetration,nof lubricating grease,thepenetration at 25C(77F),without delay,of a sample after 60double strokes in a standard grease worker.D2173.1.7 working,nof lubricating grease,the subjection of asample to the shearing action of the standard grease worker.D2173.2 Definitions of Terms Specific to This Standard:3.2.1 roll stability,nof lubricating grease,the change inconsistency of a sample after a specified amount of working ina test apparatus utilizing a weighted roller inside a rotatingcylinder.4.Summary of Test Method4.1 The Test Methods D1403 cone penetration of an ap-proximately 50-g aliquot of lubricating grease is determined.The grease is then subjected to low shear at 20 to 35C for 2h 6 5 min in a standard roll stability apparatus,before the conepenetration is again measured.The difference between the cone1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.G0.02 on Consistency and Related Rheological Tests.Current edition approved Jan.1,2011.Published January 2011.Originallyapproved in 1961.Last previous edition approved in 2006 as D183100(2006).DOI:10.1520/D1831-11.2For 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 International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 penetration before working and the cone penetration after isused as a measure of the effect of low shear working on greaseconsistency.5.Significance and Use5.1 The roll stability test is widely used in specifications.Test results are significant insofar as they can show a direc-tional change in consistency that could occur in service.Noaccurate correlation is established between the test results andshear stability in actual service.6.Apparatus6.1 Roll Stability Test Appar