Strength of differently cooled cast iron subjected to cyclic loading

Abstract

The paper presents the results of experimental andanalytic investigation of cyclic fatigue of a common and aspecially cooled cast iron. A well-known type of cast ironwas modified by casting to receive better mechanical propertiesand strength to formation and propagation of crack.Established indices of mechanical properties show that aspecial cooling modifies structure, enhances plasticity andequalises limits of yield stress and tensile strength. Thestructure of cast iron includes graphite flakes of varioussize. Graphite of a specially cooled cast iron is of sphericalshape, lesser size and are equalised by size. By tryingcompact tensile specimens CT limit ranges of stress intensityfactor were established depending on following factorsof mechanical properties: hardness, elasticity, and mechanicalproperties ratio ratio. An analytic expression of ΔKthand factors of dependence on mechanical properties wereproposed may be applied to calculations of strength of cyclicload high clearance parts.