Measurements of bending strength and modulus of elasticity in bending should be made for materials whose principal stressing mode is bending. For many materials, the tensile and compressive moduli are somewhat different. Since the bending modulus is a combination of the tensile and compressive moduli, it is often different from each of them.

Precise measurements of the modulus of elasticity in bending and bending strength require due regard for numerous variables that may affect their determination. These include (1) characteristics such as specimen orientation with respect to the rolling direction, grain size, residual stresses, previous strain history, dimensions and specimen preparation, orientation of deformed grains relative to the direction of the normal stress; and (2) test conditions, such as tem-
perature, temperature variations, condition of the test equipment and adherence to the recommended test procedure.

1.1 This standard describes three test methods for determining the modulus of elasticity in bending and the bending strength of metallic strips or sheets intended for the use in flat springs:

1.1.1 Test Method A—a cantilever beam,

1.1.2 Test Method B—a three-point loaded beam (that is, a beam resting on two supports and centrally loaded), and

1.1.3 Test Method C—a four-point loaded beam (that is, a beam resting on two supports and loaded at two points equally spaced from each support).

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

6.1 This test method covers the determination of the modulus of elasticity in bending and the offset yield strength in bending of flat metallic strips or sheets for spring applications. The test procedure involves measurements of the applied moment and the corresponding angle of deflection of a cantilever beam. The thickness range covered is 0.015 to 0.130 in. (0.38 to 3.30 mm). This test method is not applicable for nonlinear elastic materials.