1、Designation: B 223 08Standard Test Method forModulus of Elasticity of Thermostat Metals (CantileverBeam Method)1This standard is issued under the fixed designation B 223; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the modu-lus of elasticity of thermostat metals at any temperaturebetwee
3、n 300 and +1000F (185 and 540C) by mounting thespecimen as a cantilever beam and measuring the deflectionwhen subjected to a mechanical load.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 provi
4、ded 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 appropriateMater
5、ial 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:2B 388 Specification for Thermostat Metal Sheet
6、and Strip3. Terminology3.1 Definitions:3.1.1 thermostat metal, na composite material, usually inthe form of sheet or strip, comprising two or more materials ofany appropriate nature, metallic or otherwise, which, by virtueof the differing expansivities of the components, tends to alterits curvature
7、when its temperature is changed.3.1.2 modulus of elasticity, nthe ratio, within the elasticlimit of a material, of stress to corresponding strain. In this testmethod the modulus of elasticity is calculated from theexpression for the deflection of a cantilever beam undermechanical load which is trans
8、posed to read as follows:E 5 4Pl3/dbt3where:E = modulus of elasticity, psi or MPa,P = load, lbf or N,l = gage length, in. or mm,d = specimen deflection, in. or mm,b = specimen width, in. or mm, andt = specimen thickness, in. or mm.4. Apparatus (Figs. 1-3)4.1 Specimen Holder for securely clamping the
9、 test speci-men in a horizontal position as a cantilever beam whenimmersed in a bath at the desired temperature. It shall carry amicrometer depth gage for reading the deflection of thespecimen and a loading rod for loading the specimen. Both ofthese shall extend sufficiently above the liquid level o
10、f the bathto permit the operator to perform the test at the higher testtemperatures.4.1.1 Specimen holder to be made sufficiently rigid to allownormal handling without distortion.4.2 Loading Rod,18 in. (3.2 mm) or less in diameter, forcarrying the load and transmitting its weight vertically to thefr
11、ee end of the cantilever specimen. It shall be made of a lowexpansion material; the mounting clamp and tube shall bemade of the same material as the specimen mounting clamps inorder to prevent a difference in expansion rates from affectingthe deflection readings. The bottom end shall be conicallysha
12、ped and shall rest in the conical punch mark at the free endof the specimen.Any supports shall permit free movement withspecimen deflection and shall provide electrical insulation from1This test method is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct r
13、esponsibility of SubcommitteeB02.10 on Thermostat Metals and Electrical Resistance Heating Materials.Current edition approved April 1, 2008. Published May 2008. Originallyapproved in 1948. Last previous edition approved in 2003 as B 223 - 03.2For referenced ASTM standards, visit the ASTM website, ww
14、w.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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the
15、micrometer depth gage. Near the top shall be a holder forsupporting the load. The weight of the loading rod and holdershall be no greater than 1 oz (28 g).4.3 Micrometer Depth Gage, for measuring the deflection ofthe specimen to the nearest 0.0001 in. (0.002 mm). It shall bemounted directly over the
16、 loading rod. The micrometer shaftshall be in the same vertical line as the loading rod, so thatreadings can be taken of the top of the loading rod for no-loadand full-load positions. The gage shall be insulated electricallyfrom the specimen holder and the loading rod.4.4 Load, constructed so that w
17、hen placed in the holder, itscenter of gravity will coincide with the center of the loadingrod. It shall be readily detachable for the operators conve-nience in taking no-load and full-load readings and shall not beof sufficient weight to deflect the specimen more than 0.30 in.(7.6 mm).4.5 BathA sti
18、rred liquid so that the temperature shall besubstantially constant during the test.4.6 Electronic Indicator, sensitive, low-current, to give asignal when the micrometer depth gage shaft completes theelectrical circuit across the indicator terminals by touching thetop of the loading rod. The indicato
19、r sensitivity shall be suchthat loading rod positions can be determined with a precision of60.0001 in. (0.002 mm).4.7 All metallic components of apparatus, excluding mi-crometer and loads, should be made of very low coefficient ofthermal expansion materials. The recommended material isinvar.5. Preca
20、utions5.1 Load and no-load readings of the various trials will notapproximately duplicate each other in the event the load issufficiently great to overstress the specimen beyond its elasticFIG. 1 Testing Machine for Determining Modulus of Elasticity of Thermostat MetalFIG. 2 Specimen Mounting Clamp
21、AssemblyB223082limit. In this case a new specimen shall be substituted and alighter load used which will not overstress the material.5.2 Modulus of elasticity measurements to be within themaximum recommended temperatures as stated in Specifica-tion B 388.6. Test Specimen6.1 The test specimen shall b
22、e the form of a strip approxi-mately 114 in. (31.8 mm) longer than the gage length. Thethickness may be any value between 0.015 and 0.055 in. (0.38and 1.40 mm); however, corresponding width values shallconform with those in Fig. 4. Width and thickness dimensionsshall be determined with a precision o
23、f 60.0001 in. (0.002mm).7. Preparation of Specimen7.1 Gage LengthThe gage length shall be the distance onthe specimen between the center of the punch mark thatsupports the loading rod and the edge of the specimen holderclamps.This punch mark shall be approximately one half of theFIG. 3 Specimen Moun
24、ting Clamp DetailsFIG. 4 Width of Test SpecimenB223083thickness of the specimen deep and located on the center line14 in. (6.4 mm) from the free end on low expansion sidesurface. To obtain the necessary accuracy in gage length, thespecimen shall be made as shown in Fig. 5 which, when thespecimen is
25、placed in the specimen mounting clamps, willmaintain the gage length with a tolerance of 60.003 in. (0.08mm). Table 1 gives the gage lengths for various specimenthicknesses.NOTE 1For thicknesses, widths, and lengths not covered by this testmethod, the procedure shall be agreed between the manufactur
26、er and thepurchaser.7.2 After being roughly cut, slit, or sheared from the sample,the test specimen shall be finished to size by careful machiningor filing.7.3 Preforming OperationThe specimen shall be pre-formed into a shape approximating the segment of a circle. Theamount of this preforming shall
27、be such that, when subjected tothe desired temperature, the specimen will take an upwardcurvature sufficient to cause the no-load and full-load deflec-tion positions to be approximately equally distant above andbelow the straight position (Fig. 6).7.4 Heat TreatmentAfter the preforming work has been
28、completed the specimen shall be heat treated to relieve allinternal stresses. This treatment shall consist of heating thespecimen while free to bend at a prescribed temperature and fora prescribed time. Heat treatment shall be at least 50F higherthan the maximum tested temperature at a soak time of
29、1 h. Thedetails of this procedure will depend on the characteristics ofthe thermostat metal and shall be mutually agreed upon by themanufacturer and the purchaser.7.5 MarkingAny identification marking shall be placedon that part of the fixed end of the specimen not included in thegage length.8. Proc
30、edure8.1 CleaningCarefully remove any oxide coating andother foreign substances from all those surfaces which directlyaffect the electrical resistance of the electronic indicator circuitthrough the testing apparatus. This operation is necessary topermit maximum sensitivity of the indicator. The top
31、of theloading rod which touches the micrometer depth gage shaftmay be ground to a point in order to further increase theindicator sensitivity.8.2 Test RoutineClamp the specimen securely in thespecimen holder using the 0.125-in. (3.18-mm) dowel hole and0.125-in. dowel pin for accurate positioning. Lo
32、wer the bottompart of the specimen holder with the specimen into the bath ofthe desired temperature and support the apparatus rigidly. Placethe lower end of the loading rod in the punch mark at the freeend of the specimen. Connect the electronic indicator toterminals on the specimen holder. When sat
33、isfactory initialconditions have been established, adjust the micrometer depthgage until the electronic indicator signals that the gage shaft istouching the loading rod and record this position as the no-loadreading. Deflect the specimen by placing the load on the loadholder and record this position
34、 of the rod as the load reading.The difference between these two readings will be the amountof deflection. Obtain an average value of deflection from ten ormore trials.8.3 Calculation of Modulus of ElasticitySubstituting thespecimen size and the average deflection for a known load inthe equation in
35、3.1.2, calculate the modulus of elasticity, E,asin the following example:FIG. 5 SpecimenTABLE 1 Gage Length of Test SpecimenSpecimen Thickness Gage Lengthin. mm in. mm0.015 to 0.0199, incl 0.38 to 0.509, incl 212 612 63.5 6 1.30.020 to 0.0249, incl 0.51 to 0.639, incl 3 612 76.2 6 1.30.025 to 0.0299
36、, incl 0.64 to 0.759, incl 312 612 88.9 6 1.30.030 to 0.0349, incl 0.76 to 0.889, incl 4 612 101.6 6 1.30.035 to 0.0449, incl 0.89 to 1.139, incl 412 612 114.3 6 1.30.045 to 0.055, incl 1.14 to 1.40, incl 5 612 127.0 6 1.3FIG. 6 Relationship of Specimen No-Load, Straight, and Full-LoadPositions at T
37、est TemperatureB223084E 5 4Pl3/dbt3where:P = 4.00 ozf = 0.250 lbf or 1.112 N,l = 4.00 in. or 101.6 mm,d = 0.1863 in. or 4.732 mm,b = 0.5000 in. or 12.700 mm, andt = 0.0301 in. or 0.765 mm.Substituting the known values,E =(43 0.250 lbf 3 (4.00 in.)3)/0.1863 in. 3 0.500 in. 3 (0.0301 in.)3)E = 25 194
38、029 psi.orE =(43 1.112 N 3 (101.6 mm)3)/(4.732 mm 3 12.700 mm 3 (0.765mm)3)E = 173 386 MPa.9. Report9.1 The report shall include the following:9.1.1 Type of thermostat metal,9.1.2 Dimensions of specimen in inches or millimetres,9.1.3 Temperature of test,9.1.4 Direction of grain on specimen, and9.1.5
39、 Modulus of elasticity in pounds-force per square inchor megapascals.10. Precision and Bias10.1 PrecisionThe precision of this test method wasperformed in accordance with the test procedure and loadknown to 60.04 % results in a 2-sigma measurement precisionof 61.8 %.10.2 BiasComparison to accepted r
40、eference values indi-cates lack of bias.11. Keywords11.1 cantilever; loading rod; modulus of elasticity; thermo-stat metalASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expre
41、ssly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised
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43、ttend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B223085
