ASTM_B_106_-_08_2013.pdf

Designation:B10608(Reapproved 2013)Standard Test Methods forFlexivity of Thermostat Metals1This standard is issued under the fixed designation B106;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 These test methods cover the determination of flexivity(a measure of thermal deflection rate or deflection temperaturecharacteristics)of thermostat metals.1.1.1 Test Method ATested in the form of flat strip0.015 in.(0.38 mm)or over in thickness.1.1.2 Test Method BTested in the form of spiral coils lessthan 0.012 in.in thickness.1.2 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.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 become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet(MSDS)for this product/materialas provided by the manufacturer,to establish appropriatesafety and health practices,and determine the applicability ofregulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2B389 Test Method for Thermal Deflection Rate of Spiral andHelical Coils of Thermostat Metal3.Terminology3.1 Definitions:3.1.1 thermostat metal,na composite material in the formof sheet or strip comprising two or more metallic layers ofdiffering coefficients of thermal expansion,such that the radiusof curvature of the composite changes with temperaturechange.3.1.2 flexivity(F),nthe change of curvature of the longi-tudinal center line of the specimen per unit temperature changefor unit thickness,given by the following equation:F 5 t1/R2!21/R1!T22 T1(1)To determine the flexivity between any two temperatures,T1and T2,it is necessary to measure the curvature 1/R1and1/R2at temperature T1and T2,respectively.To find the cur-vature at either temperature(Fig.1 and Fig.2),measure thedistance D.The curvature is given by the following equa-tion:1/R 5 8D/Q214Dt14D2!(2)where:R=radius of curvature of the longitudinal center line of thespecimen,in.(mm),t=thickness of test specimen,in.(mm),Q=distance between support points,in.(mm),andD=for point support(simply supported beam),=perpen-dicular distance between the longitudinal center lines ofthe lower surface of the specimen midway between thepoint supports and the straight line joining the supportpoints,in.(mm).4.Significance and Use4.1 These test methods are used for determining response totemperature change or flexivity of thermostat metal.Theflexivity is calculated from the temperatures,dimensions ofspecimen,and the relative movement of the specimen.Thesimple beam method(Method A)is the method for certifica-tion.Any use of the spiral coil method(Method B)is to bemutually agreed upon between the user and supplier.TEST METHOD AFLAT STRIPS5.Apparatus5.1 Specimen Carrier,provided with two conical supportsfor locating the specimen.The test length(that is,the distancebetween the point of contact of the specimen with one supportand the point of contact of the specimen with the other support)shall be known to within 60.005 in.(0.13 mm),and the line ofplane passing through the points of contact shall be horizontal.The specimen carrier and supports shall hold the specimenwithout constraint so that the curvature,due to its deflection,1These test methods are under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and are the direct responsibility of SubcommitteeB02.10 on Thermostat Metals and Electrical Resistance Heating Materials.Current edition approved Aug.1,2013.Published August 2013.Originallyapproved in 1984.Last previous edition approved in 2008 as B106 08.DOI:10.1520/B0106-08R13.2For 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 will follow a vertical plane passing through the line joining thepoints of contact between specimen and supports.Suitablemeans shall be used to ensure test length.5.2 Micrometertraveling microscope,or equivalentdevice,so connected to the specimen carrier that expansionduring heating of the carrier or connecting parts will not causeappreciable displacement of the measuring device with respectto the supports.5.3 BathA stirred liquid bath or uniformly heated enclo-sure in which the specimen carrier,together with adjustableelectric heating source is placed.The specimen needs to bemaintained a