Optimization of heat treatment process for cast steel 50SL

The attainment of the necessary mechanical and operational properties in cast steels typically involves heat treatment, leading to a consequent increase in the final part’s cost by 30–60 %. In this study, we have enhanced the heat treatment process for cast steel 50SL, streamlining the entire procedure into a single cycle rather than the conventional two-cycle method required for cast steels. This process involves homogenization annealing followed by subsequent quenching through reheating, alongside appropriate tempering to achieve the desired mechanical and operational characteristics. Through our research, it was demonstrated that the optimal heat treatment regimen for cast components of railway cars involves heating to 950 °C, maintaining this temperature, followed by controlled cooling in a furnace to 850 °C, with a brief hold before final cooling in water. Subsequent tempering is conducted at 350 °C for 2 hours. This refined heat treatment protocol, consolidated into a single thermal heating process, significantly reduces the duration of the entire heat treatment cycle by 2.4 times and slashes costs by a factor of 4. Consequently, products fabricated from steel 50SL exhibit mechanical properties 10–12 % superior to those achieved through the conventional heat treatment approach, comprising annealing with furnace cooling, reheating for quenching, and subsequent tempering. The research was carried out within the state assignment in the field of scientific activity of the Ministry of Science and Higher Education of the Russian Federation (theme FZUN-2024-0004, state assignment of the VlSU).