The demand for better mechanical properties of steel tools is constant. For that reason, the use of Metal Matrix Composites (MMCs) has been used with several reinforcement elements. In this thesis project the development of a composition of tungsten, carbon and catalyst elements that yields a stable MMC after being casted with Hadfield steel by in-situ manufacturing process is set as the main goal. The thesis is divided in two big steps. The first consists of designing the experiment i.e. formulating different composition hypothesizes, and then casting those composition. The second is more focused on the characterization and analysis of the casting results. The final microstructure of the formed MMC is characterized by the use high-resolution Scanning Electron Microscopy. This technique provided high quality images of the reinforcement particles distribution as well as the particle size and homogeneity. The use of X-Ray Diffraction (XRD) and Energy Dispersive R-Ray Spectroscopy (EDS) is used to determine the composition of the final MMC formed, confirming the tungsten carbide chemical composition of the reinforcement particles. Finally, the hardness test is conducted to confirm the big differences between the reinforcement and the matrix.