In earlier works were described trends in the production of tools for die casting (hot work). Almost the entire set of issues dealt with may seem insignificant when incompletely assembled acceptance of the material and the associated risks of processing a material with an inappropriate structure, leading to a very early defect of the die. Therefore, further work will focus particularly on identifying the causes of thermal cracks and preventing a suitable choice of acceptance criteria conditions and heat treatment.

The paper describes existing requirements for tool materials. In the light of experience with these supplied materials, we have

demonstrated their considerable influence on the life of molds for die casting technology. From this research came the evaluation

methodology of these tool materials which has been used for directing the development of a new material. Based on the new regulation of

the chemical composition a sample was casted and forged after that. Then was determined the process of heat treatment and from a block

of this material a mold insert was produced. This insert is now being tested in production.