The paper presents a method of producing a grey cast iron casting locally reinforced with a titanium insert printed using SLM method (Selective Laser Melting). This article attempts to examine the impact of the selected geometry of titanium spatial insert on the surface layer formation on grey cast iron. The scope of the research focuses on metallographic examination - observation and analysis of the structure of the reinforced surface layer on a light and scanning microscope and a hardness measurement of the titanium layer area. Based on the obtained results, it was concluded that the reaction between titanium insert and metal (grey cast iron) locally develops numerous carbides precipitation (mainly TiC particles), which increases the hardness of the reinforced surface layer and local strengthening of the material. The ratio between the thickness of the support part (grey cast iron) and the working part (titanium insert) affects the resulting layers connection structure. The properties of the obtained reinforced surface layer depend mainly on the geometry of the insert (primarily on the internal dimensions of the connector) and the volume of the casting affecting the re-melting of the insert. A more concentrated structure of carbides precipitation occurs in castings with a full connector insert.