Reliable and durable modern railroad rails with a length of 120 m, characterized by excellent mechanical properties, high resistance to cracking and material microstructure modified as a result of improvement of the post-rolling cooling process
Project title
Reliable and durable modern railroad rails with a length of 120 m, characterized by excellent mechanical properties, high resistance to cracking and material microstructure modified as a result of improvement of the post-rolling cooling process
Name of Beneficiary/Beneficiaries
ArcelorMittal Poland S.A.
Name of programme
Operational Program “Smart Growth”
Competition
Fast Track
Project value
PLN 103,916,604.18
Funding value
PLN 42,028,818.02
Project delivery period
01.01.2019 – 06.03.2024
Our team
Head of the R&D Team: Eng. Sylwester Żak, Sc.D.
R&D Team Member: Eng. Piotr Nabielski, M.Sc.
R&D Team Member: Eng. Tomasz Ropka, M.Sc.
R&D Team Member: Eng. Łukasz Cieślik, M.Sc.
Results of our work
Heat treatment line
Heat treated rails on a cooling bed
Plant’s test track
Issues addressed
As a result of the project, a technology was developed for the production of heat-treated 120 meters long rails featuring significantly better physical and functional properties than standard rails. A new technology for accelerated cooling of the rail head after the rolling process was used, which is tested in an innovative pilot line for heat treatment of rails. It enabled the production of rails with high durability and operational reliability, and therefore safer in use in a wider range of applications. Heat-treated rails are characterized by high strength, plasticity and hardness, increased resistance to brittle fracture and greater resistance to the development of operational defects on the running surface. We owe these properties to the fine-lamellar pearlite structure as a result of heat treatment after the rail rolling process. Currently produced railroad rails have a tensile strength in the range of 880-1030 MPa and a hardness on the running surface of 260-300 HBW. The new technology enabled the production of rails with a tensile strength of 1175-1300 MPa and a hardness of 350-390 HBW. The product obtained as a result of our R&D work, which is innovative on a national scale, in the form of the railroad rail with the heat-treated head, is also characterized by an increased stress intensity factor, increased fatigue strength, low level of residual stresses and a microstructure modified so that the distance between cementite lamellae in pearlite is in the range of 0.05-0.15 μm. The outstanding physical and mechanical properties of our innovative rails were confirmed during field and laboratory tests carried out in R&D units of the Upper Silesian Institute of Technology, the Railroad Institute, the Silesian University of Technology, the AGH University of Science and Technology and the Idonial Institute in Spain, among others.
Project beneficiaries
Current transport trends include the desire to increase the speed of passenger transit and the axle loads of cars in freight transport while maintaining a high level of safety. The economics of railroad and its competitiveness versus other means of passenger and cargo transport places high requirements on railroad products. Market expectations come down to the possibility of purchasing and installing rails with a long service life in all operating conditions. Heat-treated rails are characterized by greater wear resistance, resulting in extended rail service life in unfavorable conditions such as track curves, high axial loads or high speeds and by increased resistance to brittle fracture, which, as a result, makes the product more durable and safer. Therefore, the beneficiaries of the project will be passengers using rail transport, railroad companies and the broadly defined natural environment.
Major implementation challenges
One of the biggest challenges in the project was to develop and test, as a result of industrial experiments, a rail head heat treatment technology that would enable obtaining appropriate mechanical properties and a microstructure suitable for a wide range of rail profiles varying in size (especially height, head width and rail foot width) and unit weight (49-67 kg/m). The second important issue to be solved was the integration of the demonstration production line with the existing technical and technological infrastructure of a large rolling mill while ensuring full synchronization with existing production equipment. Another test for the R&D team members was the wide range of planned research and the number of tests performed. However, thanks to the well-organized work of the R&D team, all issues were successfully resolved and the project was successfully completed.
Our advice to other applicants
Our advice to other applicants is first and foremost: carefully consider the project assumptions, clearly specify the goals to be achieved at the project preparation stage, select a well-coordinated team of specialists with experience in the field in which the project will be implemented and then implement it consistently.