Work-hardening of Annealed Mild Steel under Static and Dynamic Conditions

Abstract

IT was found by Meyer¹ that when a hard ball is pressed into the surface of a metal by a force F, thus forming an impression of diameter d, the relation holds, where k is a constant depending upon the metal and ball diameter and n, the Meyer index, is a constant depending only upon the metal. The Meyer index is 2.0 for metals which do not work-harden, for example, materials already fully worked, whereas for materials which do work-harden n is greater than 2.0, the greatest value being about 2.5. It has so far only been possible to examine equation (1) under conditions of static loading, but recently a method has been described for the continuous measurement of force throughout impact², and this has been adapted for the measurement of the index n under dynamic conditions. The force used for this purpose is the maximum force of impact, and the diameter is the diameter of the impression left after impact.