Artigo:

In order to decrease fuel consumption and CO2 emissions, the use of downsized engines, with turbochargers, is a very important alternative for engines of passenger cars. Among the materials for exhaust manifolds and for turbocharger housings, silicon molybdenum compacted graphite iron (SiMo CGI) has been used for automotive application, with some advantages over SiMo ductile irons, like thermal conductivity. This paper describes how the section thickness affect the microstructure and mechanical properties of the part. For the experimental work, it was selected two types of test pieces and one turbocharger housing, covering section thickness from  5 to 60 mm, and with solidification times from 17 to 600 seconds. The results show that tensile strength can growth from 450 MPa (the minimum specification value) up to 600 MPa with decreasing section thickness. The results can be used to predict mechanical properties in all places of the casting, with a focus on the critical ones, looking to reduce weight and increase safety of the part.