The Investigation of Graphite Distribution on Diffusion Bonding of the AISI 1030 Low Carbon Steel with Nodular Cast Iron

Abstract

Abstract The joining of Nodular Cast Iron with the conventional methods presents many problems due to the presence of high carbon content and low ductility. Therefore it is necessary to use heat treatment or to take some precautions before and after bonding. In this study, the graphite distribution on both sides of the interface of diffusion bonding of the AISI 1030 low carbon steel with Nodular Cast Iron was investigated. In order to observe the behavior of the graphite nodules in diffusion bonding, AISI 1030 was used as the comparison of alloy. Diffusion bonding experiments were carried out in an argon atmosphere at the temperatures of 900–950 and 1000 °C and 15 MPa under a dynamic load for 50–100 and 150 min. holding times. The properties of microstructure and graphite distribution that formed in the interface zone of the joints were examined by optic microscope, SEM, EDS, and X-Ray analysis. The hardness values from the interface were measured with the HV hardness scale. The strength of the joint was tested by lap-shear tests. The result of all observations indicated a homogenous graphite distribution. On the other hand, as a function of the process temperature elevation, an increase in the amount of graphite atoms that migrated towards the interface and a decrease in the nodule diameters were observed.