ASTM_B_114_-_07_2013.pdf

Designation:B11407(Reapproved 2013)Standard Test Method forTemperature-Resistance Constants of Sheet Materials forShunts and Precision Resistors1This standard is issued under the fixed designation B114;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 This test method covers the determination of the changeof resistance with temperature of sheet materials used forshunts and precision resistors for electrical apparatus.It isapplicable to materials normally used in the temperature rangeof from 0 to 80C.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 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:2B84 Test Method for Temperature-Resistance Constants ofAlloy Wires for Precision Resistors3.Significance and Use3.1 This test method covers the determination of the changeof resistance with temperature for precision resistors andshunts made from sheet materials.3.2 Materials normally used in the temperature range from 0to 80C may be tested using this test method.4.Test Specimen4.1 The test specimen shall be of such dimensions that itselectrical resistance can be measured to the required accuracy.NOTE1Measurements are simplified if the specimen has a resistanceof 0.01 or more.The specimen may be bent in the form of a“U”tofacilitate handling.5.Terminals5.1 A current terminal shall be attached to each end of thespecimen.These terminals shall be either soldered or clampedin such a manner that there will be no change of currentdistribution in the specimen during the test.5.2 Potential terminals,one at each end,shall be located ata distance not less than two times the width of the specimenfrom the current terminals.These terminals shall be attached atthe center of the width of the specimen either by soldering toears cut out of the specimen(Note 2)as shown in Fig.1 or byclamps,each of which presses a single sharp point into thematerial.NOTE2The ears shall be cut so that they are about12in.(12.7 mm)in length and18in.(3.2 mm)in width.The cut shall be clean and free fromslivers at the junction of the ear and the specimen.Before cutting the ears,it is desirable to drill two small holes with a sharp drill where the ear willbe jointed to the specimen.6.Preliminary Treatment for Manganin Samples6.1 In the case of manganin materials,after all the mechani-cal work has been finished,the specimen shall be given oneheat treatment of 48 h at 140 6 5.0C and then cooled to roomtemperature.6.2 The specimen shall then be given a dip in a nitric acidsolution(50%)to remove the copper film(which can bejudged by the color of the specimen)and then thoroughlyscrubbed in running water.7.Apparatus7.1 The apparatus for making the test shall consist of one ormore baths for maintaining the specimen at the desired1This 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 Resistance Heating Materials.Current edition approved May 1,2013.Published May 2013.Originallyapproved in 1938.Last previous edition approved in 2007 as B114 07.DOI:10.1520/B0114-07R13.2For 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 temperature,thermometers for measuring the temperatures ofthe baths,and suitable means for measuring the resistance ofthe specimen.8.Baths8.1 Each bath shall consist of chemically neutral oil.The oilshall be of such quantity and so well stirred that the tempera-ture in the region occupied by the specimen and the thermom-eter shall be uniform within 0.2C for any temperature between0 and 80C.8.2 In an automatically controlled bath,the temperature ofthe bath at any time during the test at any temperature levelshall not differ from its mean temperature by more than 0.2C.In a manually controlled bath,the rate of change of tempera-ture shall not exceed 0.2C/min.9.Temperature Measurement9.1 The temperature shall be measured by a calibratedtemperature measuring device of suitable