ASTM_D_6515_-_00_2010.pdf

Designation:D651500(Reapproved 2010)Standard Test Method forRubber Shaft Seals Determination of Recovery FromBending1This standard is issued under the fixed designation D6515;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.1.Scope1.1 This test method covers a procedure to determine therecovery response of rubber after particular bending deforma-tion,subsequent to aging in selected media at a specifiedtemperature,and for a specified time period,thus providing ameasure of the relative performance potential of compoundsused in the manufacture of shaft seals.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,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:2D412 Test Methods for Vulcanized Rubber and Thermoplas-tic ElastomersTensionD471 Test Method for Rubber PropertyEffect of LiquidsD1349 Practice for RubberStandard Temperatures forTestingD3183 Practice for RubberPreparation of Pieces for TestPurposes from ProductsD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3.Summary of Test Method3.1 The ends of rectangular specimens of candidate shaftseal compounds are clipped together and the specimens ex-posed under specified conditions of time and temperature in afluid environment that best simulates anticipated operatingconditions.Upon completion of the exposure,the clamps areremoved and the specimen are allowed to recover frombending.After a specified period of time,the distance betweenends of the specimens is measured and the amount of recoverycalculated.4.Significance and Use4.1 Among the factors affecting shaft seal life are the abilityto retain elasticity and compensate for shaft eccentricity,abilityto recover from bending,and resistance to wear and theswelling effects of contact fluids.In-service testing of candi-date materials is time consuming and therefore costly.Mea-surement of recovery from bending after exposure in fluids atelevated temperatures provides a means of quickly assessingthe materials potential and acceptability for use.Comparativerecovery data may then be screened and optimum performingcompounds selected for further improvement or seal fabrica-tion.It has been found that good to excellent correlation existsbetween a materials ability to recover from bending andsealing effectiveness.4.2 This method is designed to measure the recovery ofdifferent rubber compounds after aging in any liquid medium,including hydraulic oils and water.This method can also beused to test rubber compounds after aging in air.Test liquidsshould be chosen based on the intended end use.5.Apparatus5.1 Glass Test Tubes,300 by 38 mm(12 by 112in.)5.2 Specimen Hangers.5.3 Binder Clips.5.4 Aluminum Block Heater.5.5 Aluminum Plate,300 by 400 by 2.3 mm(12 by 16 by0.09 in.)with surface roughness,Ra=0.40.5 m(16 to 20in).5.6 Tweezers.5.7 Oven.5.8 Ruler,graduated in 0.5 mm(0.02 in.).1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.37 on Coated Fabrics,RubberThreads and Seals.Current edition approved June 1,2010.Published December 2010.Originallyapproved in 2000.Last previous edition approved in 2009 as D6515 00(2009).DOI:10.1520/D6515-00R10.2For 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 6.Test Temperatures6.1 Unless otherwise specified,the standard temperature fortesting shall be 23 6 2 C(73.4 6 3.6 F).Specimens shall beconditioned for at least 3 h when the test temperature is 23 C(73.4 F).If the material is affected by moisture,maintain therelative humidity at 50 6 5%and condition the specimens forat least 24 h prior to testing.When testing at any othertemperature is required,use one of the temperatures listed inPractice D1349.7.Test Specimen7.1 Test specimens shall be cut from test sheets with athickness of 2.0 6 0.2 mm(0.080 6 0.05 in.)of eachcompound to be evaluated,prepared according to the proce-dure detailed in Practice D3183.Test sheets shall be vulcanizedaccording to the same conditions of time and temperature aswould be used for molding the sheets for testing physicalproperties in tension(see Test Method D