1、Designation: B 362 91 (Reapproved 2003)Standard Test Method forMechanical Torque Rate of Spiral Coils of Thermostat Metal1This standard is issued under the fixed designation B 362; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e year of 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 The test method covers the principles of determining themechanical torque rate of spiral coils of thermosta
3、t metal.NOTE 1This test method has been developed particularly to cover thedetermination of the mechanical torque rate of spiral coils made ofthermostat metal for carburetors and manifold heat controls. The methodis not limited to thermostat metals and can be used for spiral coils of othermaterials
4、for which the torque rate must be measured accurately.1.2 The values stated in inch-pound units are to be regardedas the standard. The metric equivalents of inch-pound unitsmay be approximate.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It
5、 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 determine the applicabili
6、ty of regulatorylimitations prior to use.2. Terminology2.1 thermostat metala composite material, usually in theform of sheet or strip, comprising two or more materials of anyappropriate nature, metallic or otherwise, that, by virtue of thediffering expansivities of the components, tends to alter its
7、curvature when its temperature is changed.2.2 mechanical torque ratethe ratio of torque to deflec-tion. It is a measure of the stiffness of the coil and may have theunits of ounce inch or gram centimetre per angular degree.2.3 spiral coila part made by winding strip on itself.3. Summary of Test Meth
8、od3.1 The test for mechanical torque rate of spiral coilsconsists of applying a torque, or moment of force, that will notstress the material in excess of its elastic limits, to the coil andmeasuring the resulting deflection as angular rotation. Of theseveral methods for obtaining this value, it is p
9、referred that theouter end of the spiral coil be held stationary, but not fixed, andthe inner end of the coil be rotated after applying a load to theouter end of the coil at a fixed radius.4. Significance and Use4.1 This test method is useful to determine the mechanicalforce of spiral coils of therm
10、ostat metal.4.2 The mechanical properties of a coil may vary from lot tolot of thermostat metal material. This method is useful fordetermining the optimum thickness and length of the materialfor a given mechanical torque specification.4.3 This test is useful as a quality test to determine accep-tanc
11、e or rejection of a lot of thermostat metal coils.5. Apparatus5.1 The determination of the mechanical torque rate ofspiral coils is subject to many variables and is sensitive to thedegree that even different apparatus employing the same testprinciples will give different results. Therefore it is rec
12、om-mended that the apparatus be standardized. The apparatusshown in Fig. 1 and Fig. 2 and consisting essentially of thefollowing components, has been found satisfactory:5.1.1 Specimen HolderA specimen holder shall providefor securely holding the inner end of the test specimen.Preferably, the holder
13、or mounting arbor shall be of circularcross section whose diameter is as large as possible withouttouching the inner turn of the coil under any test conditions ofload. The end of the arbor shall be slotted entirely across itsdiameter, to a depth greater than the width of the specimen, andof a width
14、slightly narrower than the thickness of the specimen.Thus, the inner tab will be a push or snug fit in the slot for itsentire width. The edges of the slot shall be sharp where itintersects the circumference of the arbor. The slot shall be sopositioned in the arbor that the center of rotation of the
15、arborand the coil will coincide.5.1.2 ProtractorThe angular deflection due to the testtorque shall be measured by a protractor with a minimumdivision of 0.5 angular degrees.5.1.3 Loading PinThe loading pin is the member bymeans of which the load is applied to the outer end of the coil.The pin shall
16、be preferably of circular cross section approxi-mately332 in. (2.4 mm) in diameter. The distance from the1This test method is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.10 on Thermostat Metals and Electrical Resista
17、nce Heating Materials.Current edition approved June 10, 2003. Published July 2003. Originallyapproved in 1960. Last previous edition approved in 1991 as B 362 91 (1997)e1.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.center line of
18、 the mounting arbor to the center line of theloading pin shall be specified.6. Sampling6.1 Test for mechanical torque rate of spiral coils shall betaken in a manner to assure representative sampling of the testlot. A lot, for quality control purposes, comprises of thefinished yield of one bonded coi
19、l of material. Sampling shallconsist of parts made from each cut of material across thebonded width. Frequency of sampling shall be mutually agreedupon between the manufacturer and the purchaser.7. Procedure7.1 StabilizationAfter all forming operations and beforetesting, subject the specimen to a st
20、abilizing heat treatment torelieve internal stresses. This treatment shall consist of heatingthe specimen, while free to rotate, for a prescribed time andtemperature. The details of the stabilizing procedure willdepend upon the characteristics of the thermostat metal beingtested and shall be mutuall
21、y agreed upon between the manu-facturer and the purchaser.7.2 Test Routine:7.2.1 Place the test specimen on the mounting arbor center-ing the inside diameter of the coil on the arbor. To minimizefrictional effects vibrate the apparatus.7.2.2 Initial TorqueApply an initial torque to the coil toestabl
22、ish initial conditions prior to applying the test torque. Theinitial torque shall be in accordance with the following tableand shall be known to an accuracy of 6 2%.Initial Torque, ozin. (gcm) Test Torque, ozin. (gcm)0.5 (36) 1 to 4 (72 to 288) incl1.0 (72) over 4 to 12 (over 288 to 864)Record the a
23、ngular position of the indicating pointer while under the initialtorque.7.2.3 Test TorqueApply the test torque and record theangular position of the indicating pointer. The test torque shallbe as large as possible without causing turns of the coil totouch, or without exceeding the elastic limits of
24、the material. Inclosely wound low-torque rate coils where turns may touch,this fact shall be noted in the report. The test torque in ounceinches (or gram centimetres) shall be known to an accuracy of0.5 %.7.2.4 Remove the test torque and check the initial readingobtained with the initial torque. If
25、any deviation is found,reapply the test weight until two consecutive values of thedeflection due to the test torque are the same.7.2.5 The angular rotation in degrees shall be known to anaccuracy of 0.25. During the test, the temperature shall beheld constant.8. Calculation8.1 Calculate the mechanic
26、al torque rate by multiplying thetest weight by its moment arm and dividing the product by theangular deflection produced by the test torque, as follows:M 5 PL/Awhere:M = mechanical torque rate,P = weight, oz (or g),L = moment arm, in. (or cm), andA = angular rotation, deg.9. Report9.1 The report sh
27、all include the following:9.1.1 Type of material,9.1.2 Dimensions of material,9.1.3 Dimension of coil,FIG. 1 Schematic Design of ApparatusFIG. 2 Typical Design of ApparatusB 362 91 (2003)29.1.4 Test temperature,9.1.5 Dimension of arbor,9.1.6 Dimension of loading pin,9.1.7 Location of loading pin,9.1
28、.8 Initial torque,9.1.9 Test torque, and9.1.10 Torque rate value.10. Precision and Bias10.1 The reliability of the results of the mechanical torquerate depends on the method and apparatus.10.2 The bias of test is that prescribed in Sections 5 and 7.11. Keywords11.1 mechanical torque rate; spiral coi
29、l; thermostatASTM 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, and the riskof infringement of suc
30、h 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, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for addit
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32、 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).B 362 91 (2003)3
