INTRODUCTION This Item is intended to provide representative values for a number of material properties required in approximate calculations associated with tribology. With many materials a wide range of property values is attainable by@ for example@ heat-treatment or small changes in composition. The quoted values are@ therefore@ only typical values likely to be met in tribological applications. Where more precise values are required@ the user is advised to consult the specification for the particular material of interest. Unless otherwise stated@ all material properties are quoted for room temperature (20??.