The main scientific objective of the Project concerns the formation of a nanocrystalline structure in low and medium-alloy steels with the use of phase transformations. Nanocrystalline structure allows to obtain a unique set of mechanical properties in such steels: high strength with adequately high yield strength and high resistance to cracking.
The intention of the Project is to produce a homogeneous nanocrystalline structure in a cross-section of the workpiece that is sufficiently large for practical applications.
Due to high resistance to cracking, such nanocrystalline steels will provide a higher level of structural reliability, which is critical in applications that require high safety factors (aviation, automotive, armaments industry).
- Project title: Production of nanocrystalline steels using phase transformations.
- Implementation period: 01.04.2009 - 31.12.2014
- Authorisation Holder: Warsaw University of Technology, Entity is directly involved in the Project is the Department of Materials Science and Engineering.
- Legal base: Contract with the Ministry of Science and Higher Education No. UDA-POIG.01.01.02.-14-100/09-00 dated 31.12.2009.
- Project Manager: Wiesław Świątnicki, Ph.D., D.Sc., Eng.
- Source of funding: Project is co-financed by the European Union under the European Regional Development Fund and by the state budget.
The object of the Project is to develop a production technology for a nanocrystalline steel. This technology will be based on a carefully designed heat treatment of steels that have specially selected chemical composition.
In order to effectively achieve the objectives of the Project, it was divided into six main tasks:
Task no 1: The examination and analysis of the phase transformations processes that occur in steels selected with respect to their presumed suitability to produce desired nanocrystalline structures.
The aim of the task is to determine the type and the kinetics of phase transformation that occurs at a given temperature and to determine the characteristic points of phase transformations. For the purpose of these studies, dilatometric tests are performed. The obtained results will make it possible to specify heat treatment parameters that allow the formation of the nanocrystalline structures.
Task no 2: Heat treatment of steels aimed at the formation of nanocrystalline structures.
For the purpose of this task, the processes of heat treatment are carried out, both in the laboratory and in semi-technical conditions, in order to produce nanocrystallines structures in steels.
Task no 3: The characterization of steels microstructure after heat treatment.
In this task, the microstructure of the heat treated specimens is examined with the use of the light microscopy techniques and transmission electron microscopy. The aim of the research is to investigate the phase composition and the microstructure of investigated steels after various heat treatment processes. The heat treatment processes, which lead to the formation of homogeneous nanostructure in steels, will be optimized in order to ameliorate the mechanical and service properties of the investigated steels.
Task no 4: The determination of mechanical properties of heat-treated steels.
Nanocrystalline steels, selected in the previous task, are subject to various mechanical tests verifying their hardness, strength, ductility, impact strength and resistance to cracking. The aim is to verify which heat treatment processes provide the best compromise for steels properties, such as: strength, ductility and resistance to cracking.
Task no 5: The determination of functional and service properties of steels.
In this task, the fatigue strength and wear resistance are determined, which are important from the point of view of a practical applications. In addition, tests of stability of mechanical properties are performed as a function of the temperature. The aim is to examine whether, and to what extent, the nanostructure formed in steel is resistant to external conditions. In addition, technological tests are carried out in order to find the potential applications for the newly developed steels.
Task no 6: The optimization of the production technology for the nanocrystalline steels. Popularisation of the obtained results within the industry.
This is the key task in the project, as it covers the analysis of the obtained results from the tasks 1÷5. The objective is to determine the best chemical composition of steels and heat treatment parameters that would allow the production of the steels with nanostructure that provides the most optimal mechanical properties. The purpose of this task is to develop procedures and technological guidelines for nanocrystalline steels that will have the desired mechanical properties in terms of practical applications. In addition, this task includes work on the implementation of the developed technologies within the industry.
The aim of the Project, is to transfer the know-how of the developed nanocrystalline steel technology into practice. Therefore, it is planned to implement this newly developed technology, along with its patenting, into steel manufacturing industry. Based on the scientific knowledge, nanocrystalline steel manufacturing technology will contribute to the growth of innovation and the competitiveness of polish companies that will implement it.