Specifications and Selection of Gray Irons
Gray irons are commonly classified by their minimum tensile strength. This article describes properties used in the selection of gray irons and the factors that affect properties, particularly the effect of solidification. It discusses the three steps that its processing undergoes in the foundry: liquid metal preparation, solidification, and solid-state transformation. The article discusses the tensile properties of gray cast iron: tensile strength, yield strength, ductility, and modulus of elasticity. It describes hardness tests that are performed for determining the approximate strength characteristics and machinability of a gray iron casting. The article also presents typical mechanical properties of heat-resistant gray irons in a table. It concludes with information on the automotive application of alloy cast irons.