RESULTS OF STRUCTURAL HEAT-RESISTANT MATERIALS FOR THE MANUFACTURE CYLINDER HEAD

Abstract

The purpose of researches is improving the heat resistance of the material of the cylinder head (cylinder head), the rationale of the chemical composition and structure of this part. Under low-cycle thermal loading occurs gradually relaxation of thermal stresses in the presence of already formed permanent deformation. This causes tensile stresses are particularly dangerous for grey cast iron used to manufacture the cylinder head. The tensile strength of the material in tension is several times less than in compression. Each thermal Cycling, the tensile stress will increase, as gray cast iron has low plasticity. Residual deformation will increase and will eventually lead to termostatical cracks. The material of the head, cast iron SCH25, has a graphite inclusions plate shape. The structure of the material is not optimal for improved heat transfer, which also increases thermal stresses on the surface and the thickness of firing the bottom and leads to cracks. This defect limits the resource of the cylinder head. For the rational choice of the material of this part was used in the experimental setup. Based on the analysis of the results of the studies, it wasfound that the maximum thermal resistance, 160 cycles, has vermicular cast iron. Increased thermostability show cast irons with such alloying elements as copper, Nickel, molybdenum. Found that the use of dopants optimal chemical composition and structure of vermicular cast iron will significantly improve the durability of the cylinder head.