The basic goal of the project is the development of advanced tool steel for the most demanding applications in industry, which means achieving significantly better properties compared to those of existing tool steel. With the current production technology and with the available infrastructure, SRS achieves the following properties in this tool steel: hardness 58-60 HRc, impact toughness 25 J (SBJ), tensile strength around 1900 MPa. This tool steel has some disadvantages: in the case of using this steel for the production of industrial knives, the knives have a service life of only 6 hours, and the knives can only be used at lower cutting speeds, i.e. up to 190 m/min. The mentioned shortcomings limit the wider use of this tool steel for the most demanding applications in industry, where there are requirements regarding the lifetime of such products (over 10 hours) and the need to achieve cutting speeds of around 400 m/min. As part of the project, the main goal is to develop a new advanced tool steel, where by correcting the chemical composition → i.e. by determining the alloying elements and their amounts, as well as by the appropriate production technology and subsequent heat and mechanical treatment, significantly changed the phase balances in the Fe-C and Fe3C systems and, consequently, the properties of the new steel. The newly developed steel must have a microstructure based on sputtered martensite with a minimum content of impurities and other inappropriate inclusions. To carry out this development, it will be necessary to carry out a study of the influence of Cr and microalloying elements (known and new) on the formation of the structure of the new tool steel. Since Cr has a TCK crystal structure and stabilizes ferrite (belongs to the alphagenic elements), it will be necessary to redefine and modify its content in this tool steel. This will be followed by corrections and the introduction of new microalloy elements, all with the aim of achieving an appropriate microstructure consisting of spongy martensite during cooling during the tempering phase, which will result in high hardness and impact toughness of the new tool steel.

The development of advanced tool steel is closely related to the development of manufacturing technology, so in order to realize the goal, it will be necessary to use various characterization techniques that will establish a bridge between the newly determined chemical composition, manufacturing technology and the properties that the new tool steel must have. The first set of characterizations will thus be focused on the identification of the chemical composition, microstructure and individual phases, inclusions, after each stage of production, while the second set will be on determining the properties also after each stage of tool steel production. The purpose of these tests is to gain insight into the knowledge of the relationship: material - production - properties - final application - and is absolutely necessary if we want to dynamically monitor and target the formation of the microstructure and thus ensure the properties of the new tool steel during production and subsequent use for the most demanding and different applications in industry. In this context, it will be necessary to determine the critical cooling rates during quenching and the impact on the achievement of the final microstructure, all with the aim of ensuring the key properties of the new advanced tool steel: → hardness on the entire cutting surface = 63 HRc, → tensile strength > 2100 MPa → impact toughness 34 J (SBJ) - which is 35% higher than that of the existing material, → service life of knives made of new advanced steel = 10 hours, → use of new advanced steel for high cutting speeds - up to 400 m/min.