ASTM D 256

ASTM D 256 : Standard Test Methods for Determining the Pendulum Impact Resistance of Notched Specimens of Plastics These test methods cover the determination of the resistance of plastics to breakage by flexural shock as indicated by the energy extracted from "standardized" (see Note 1) pendulum-type hammers, mounted in "standardized" machines, in breaking standard specimens with one pendulum swing. The standard tests for these test methods require specimens made with a milled notch (see Note 2). In the Charpy (Test Method B) and Izod (Test Methods A, C and D) tests, the notch produces a stress concentration which promotes a brittle, rather than a ductile, fracture. In Test Method E, the impact strength is obtained by reversing the position in the vise of a notched specimen. The results of all tests are reported in terms of energy absorbed per unit of specimen width (see Note 3). The values stated in SI units are to be regarded as the standard. The values stated in parentheses are for information only. Click here for the complete details of the ASTM D 256.