1.1 ,This test method establishes the requirements for the determination of the reversed or repeated bending fatigue properties of copper alloy flat sheet, or strip of spring materials by fixed cantilever, constant deflection (that is, constant amplitude of displacement)-type testing machines. This method is limited to flat sheet or strip ranging in thickness from 0.005 in. to 0.062 in. (0.13 mm to 1.57 mm), to a fatigue life range of 10⁵ to 10⁸ cycles, and to conditions where no significant change in stress-strain relations occurs during the test.