During high pressure die casting process large strains appear on die casting tool. Due to large strains mechanical damage can occur. Numerical analysis were made for the tool's fixed frame plate around lower side core. Many components of die casting tool are in contact with each other. In thesis we presented numerical methods for treatment of contact mechanics. Properties of this methods were presented on simplified model. Based on results of numerical analysis we can conclude, that tensile stresses in critical areas are lower when the radius is larger and also stresses are smaller along the larger radius. Friction has a significant effect on size of stresses and slips.