1、Designation: B 223 03Standard 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 mountingthe specimen 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 the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, a
4、ssociated 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 for this product/material as pro-vided by the manufacturer, to establish appropriate safety andhealth practices, and
5、 determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:B 388 Specification for Thermostat Metal Sheet and Strip23. Terminology3.1 Definitions:3.1.1 thermostat metala composite material, usually inthe form of sheet or strip, comprising two or more
6、 materials ofany appropriate nature, metallic or otherwise, which, by virtueof the differing expansivities of the components, tends to alterits curvature when its temperature is changed.3.1.2 modulus of elasticitythe ratio, within the elasticlimit of a material, of stress to corresponding strain. In
7、 this testmethod the modulus of elasticity is calculated from theexpression for the deflection of a cantilever beam undermechanical load which is transposed 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 deflecti
8、on, 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 test speci-men in a horizontal position as a cantilever beam whenimmersed in a bath at the desired temperature. It shall carry amicrometer depth gag
9、e for reading the deflection of thespecimen and a loading rod for loading the specimen. Both ofthese shall extend sufficiently above the liquid level of the bathto permit the operator to perform the test at the higher testtemperatures.4.1.1 Specimen holder to be made sufficiently rigid to allownorma
10、l 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 thefree end of the cantilever specimen. It shall be made of materialthe same as that of the tube which supports the specimenmounting clamps in order to pr
11、event a difference in expansionrates from affecting the deflection readings. The bottom endshall be conically shaped and shall rest in the conical punchmark at the free end of the specimen. Any supports shall permitfree movement with specimen deflection and shall provideelectrical insulation from th
12、e micrometer depth gage. Near thetop shall be a holder for supporting the load. The weight of theloading rod and holder shall 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 t
13、he 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.1This test method is under th
14、e jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.10 on Thermostat Metals and Electrical Resistance Heating Materials.Current edition approved June 10, 2003. Published August 2003. Originallyapproved in 1948. Last previous edition
15、 approved in 1997 as B 223 - 97.2Annual Book of ASTM Standards, Vol. 02.04.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.4 Load, constructed so that when placed in the holder, itscenter of gravity will coincide with the center of
16、 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 stirred liquid so that the temperature shall besubstantially constant during the t
17、est.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 indicator sensitivity shall be suchthat loading rod positions can be determined with a
18、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. Precautions5.1 Load and no-load readings of the various trials will notapproximately
19、 duplicate each other in the event the load issufficiently great to overstress the specimen beyond its elasticlimit. 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 recommend
20、ed temperatures as stated in Specifica-tion B 388.6. Test Specimen6.1 The test specimen shall be 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. (0.38FIG. 1 Testing Machine for Determining Modulus of Elastici
21、ty of Thermostat MetalFIG. 2 Specimen Mounting Clamp AssemblyB223032and 1.40 mm); however, corresponding width values shallconform with those in Fig. 4. Width and thickness dimensionsshall be determined with a precision of 60.0001 in. (0.002mm).7. Preparation of Specimen7.1 Gage LengthThe gage lengt
22、h 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 thethickness of the specimen deep and located on the center line14 in. (6.4 mm) from the free end on
23、low expansion sidesurface. To obtain the necessary accuracy in gage length, thespecimen shall be made as shown in Fig. 5 which, when thespecimen is 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
24、 specimenthicknesses.FIG. 3 Specimen Mounting Clamp DetailsFIG. 4 Width of Test SpecimenB223033NOTE 1For thicknesses, widths, and lengths not covered by this testmethod, the procedure shall be agreed between the manufacturer and thepurchaser.7.2 After being roughly cut, slit, or sheared from the sam
25、ple,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 be such that, when subjected tothe desired temperature, the specimen will take
26、 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 beencompleted the specimen shall be heat treated to relieve allinternal stresses.
27、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 50 F higherthan the maximum tested temperature at a soak time of 1 h. Thedetails of this procedure will depend on the characteristics ofthe th
28、ermostat 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. Procedure8.1 CleaningCarefully remove any oxide coating andother foreign substanc
29、es 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 of theloading rod which touches the micrometer depth gage shaftmay be ground
30、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. Lower the bottompart of the specimen holder with the specimen into the bath oft
31、he 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 satisfactory initialconditions have been established, adjust the micrometer dept
32、hgage 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 of the rod as the load reading.The difference between these two readings wil
33、l 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 3.1.1, calculate the modulus of elasticity, E,asin the following example:E 5
34、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, andFIG. 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.
35、0249, incl 0.51 to 0.639, incl 3 612 76.2 6 1.30.025 to 0.0299, 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 Relations
36、hip of Specimen No-Load, Straight, and Full-LoadPositions at Test TemperatureB223034t = 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 = 25 194 029 psi.orE =(43 1.112 N 3 (101.6 mm)3)/(4.732 mm 3 12.700 mm 3 (0.765mm)3)E
37、= 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 Modulus of elasticity in pounds-force per square inchor megapascals.10. Prec
38、ision 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 reference values indi-cates lack of bias.11. Keywords11.1 cantilever; loading
39、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 expressly advised that determination of the validity of any such patent rights, an
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42、ouldmake 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).B223035
