The properties of cemented carbides depend strongly on the WC particle size and the amount of Co binder phase. The aim of the present project is to monitor WC grain growth closely and to present a model that is capable of predicting grain growth and abnormal grain growth in cemented carbides. The work involves not only modelling but a literature study and experimental work: heat treatment, SEM and image analysis of various grades that will be performed by the industrial partners as well as at KTH. The modelling based on diffusion and ledge mechanisms will be performed at KTH. It will make use of the Calphad type of thermodynamic data as well as diffusion in liquid and solid Co, interfaces and along growth ledges. Of particular interest is the effect of composition.