ASTM B362-91 pdf free.Standard Test Method for Mechanical Torque Rate of Spiral Coils of Thermostat Metal.
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 coil of material.Sampling shall consist of parts made from each cut of material across thebonded width. Frequency of sampling shall be mutually agreedupon between the manufacturer and the purchaser.After all forming operations and beforetesting, subject the specimen to a stabilizing 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 mutually agreed upon between the manu-facturer and the purchaser.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.Initial Torque Apply an initial torque to the coil toestablish 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  2%.
Apply 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 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 %.Remove the test torque and check the initial readingobtained with the initial torque. If any deviation is found,reapply the test weight until two consecutive values of thedeflection due to the test torque are the same.The angular rotation in degrees shall be known to anaccuracy of 0.25°.During the test,the temperature shall beheld constant.ASTM B362 pdf download.