ASTM B593-96 pdf free.Standard Test Method for Bending Fatigue Testing for Copper-Alloy Spring Materials.
A suitable counter and monitoring circuit is required toprovide a direct readout of the number of cycles to completefailure, that is,separation into two pieces.The test specimen shall be of the fixed-cantilever type.Several such specimens which have been used successfully areshown in Fig.2.
It is important, therefore, that care be exercised in thepreparation of test specimens,particularly in machining,toassure good workmanship. Improperly prepared test specimenscause unsatisfactory test results.The specimens are best prepared by cross milling astack, approximately 0.75 in. (19 mm) thick, including back-upplates, for which 0.12-in. (3-mm) thick brass sheet stock maybe used.It is necessary to ensure that any cutting or machin-ing operation required to either rough cut the test specimenfrom the blank,or to machine it to size does not appreciablyalter the metallurgical structure or properties of the material.All cuts taken in machining should be such as to minimizework hardening of the test specimen. In selecting cutting speeds and feed rates, due regardshould be paid to the test-specimen material, and for finishingcuts, to the quality of the surface finish required.It is not practicable to recommend a single procedure forfeeds，speeds，and depth of cut，since this will vary with the materialtested.The procedure used,however，should be noted in reporting testresults，since differences in procedure may produce variability in testresults among different laboratories.
The test specimen surface shall be in the as-receivedcondition. The edges shall not be roughed or smoothed, since this tends to give an apparent higher fatigue strength. Burrs,however, may be removed by light stoning.Test specimens from material that is used in a thermallytreated condition,such as precipitation hardened or stressrelieved, shall be treated in a manner reflecting the way thematerial will be used. The procedure used should be noted inreporting test results. Measure the machine displacement under dynamicconditions.This may be accomplished by optical means.Usespecimens having foil-type electrical resistance strain gagesmounted on the tapered area to verify that static and dynamicstrains gages mounted on the tapered area to verify that staticand dynamic strains are identical for a given displacement.ASTM B593 pdf download.