ASTM_B_769_-_11_2016.pdf

Designation:B76911(Reapproved 2016)Standard Test Method forShear Testing of Aluminum Alloys1This standard is issued under the fixed designation B769;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.Scope*1.1 This test method covers double-shear testing of wroughtand cast aluminum products to determine shear ultimatestrengths.NOTE1The values stated in inch-pound units are to be regarded as thestandard.The values given in parentheses are provided for informationonly.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 regulatory limitations prior to use.2.Referenced Documents2.1 The following documents of the issue in effect on thedate of material purchase,unless otherwise noted form a part ofthis specification to the extent referenced herein:2.2 ASTM Standards:2B565 Test Method for Shear Testing of Aluminum andAluminum-Alloy Rivets and Cold-Heading Wire andRodsE4 Practices for Force Verification of Testing MachinesE6 Terminology Relating to Methods of Mechanical TestingE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3.Terminology3.1 The definitions of terms relating to shear testing inTerminology E6 are applicable to the terms used in this testmethod.4.Summary of Test Method4.1 This test method consists of subjecting a machinedcylindrical test specimen to double-shear loading in a testfixture using a tension(or compression)testing machine todetermine the shear stress required to fracture the specimen,that is,the shear strength.5.Significance and Use5.1 The intent of this method is to provide a means ofmeasuring the ultimate shear strength of aluminum-alloywrought and cast products.Data obtained by this method areused to calculate minimum properties that can be utilized in thedesign of structural members such as found in aircraft.It isrecognized that loading conditions developed by this method,and by most others,are not ideal in that they do not strictlysatisfy the definition of pure shear.However,rarely do pureshear conditions exist in structures.NOTE2This method is not interchangeable with that described in TestMethod B565.Shear strengths obtained by Test Method B565 are about10%lower than those developed by this test method.5.2 The presence of a lubricant on the surface of thespecimen and fixture may result in shear strengths up to 3%lower than those determined in the absence of lubrication(see8.1 and Test Method B565).6.Apparatus6.1 Testing MachinesThe testing machines shall conformto the requirements of Practices E4.The loads used todetermine the shear strength shall be within the loading rangeof the testing machine as defined in Practices E4.6.2 Loading Device:6.2.1 The loading device shall be a double-shear test fixtureof the type shown in Fig.1.The fixture shall be made of toolsteel having a Rockwell hardness from 60 to 62 HRC.Asuitable alternative is to use a lower-strength steel for the mainframe of the fixture and have only the steel inserts hardenedfrom 60 to 62 HRC.6.2.2 The shearing edges of the holes shall have a radius ofno more than 0.0005 in.(0.013 mm).The mating surfaces ofthe center and outside dies shall have a finish of 16 in.(0.4 m)Raor less.There shall be sufficient clearancesbetween the die interfaces to ensure that no binding occurs;clearanceshouldnotexceed0.002in.(0.051mm).1This test method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is the direct responsibility of Subcommittee B07.05 onTesting.Current edition approved Nov.1,2016.Published November 2016.Originallyapproved in 1987.Last previous edition approved in 2011 as B769 11.DOI:10.1520/B0769-11R16.2For 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.*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 States1 Consequently,the rigidity of the test fixture must be such thatthis clearance is maintained throughout the test;in instanceswhere the device is loaded in compression as in Fig.1,caremust be taken to ensure there is no binding between the dies atthe interfaces during the test.6.2.3 The nominal length of the center and outside dies ofthe tool shown in Fig.1 is 1 in.(25.4 mm).It has beendemonstrated that die lengths of 0.5 in.(12.7 mm)for38-in.(9.52 mm)d