Naberezhnye Chelny Institute (branch) of Kazan Federal University, Naberezhnye Chelny, Russia:

V. G. Shibakov, Dr. Eng., Prof., Head of the Dept. of Mechanical Engineering, e-mail: vladshib50@gmail.com
D. L. Pankratov, Dr. Eng., Director of the Higher Engineering School, e-mail: pankratovdl@gmail.com
A. M. Valiev, Cand. Eng., Associate Prof., Dept. of Mechanical Engineering, e-mail: cct-ineka@yandex.ru
R. V. Shibakov, Cand. Eng., Associate Prof., Dept. of Mechanical Engineering

The use of microalloyed dispersion-hardening steels allows not only to save expensive alloying elements, but also leads to significant energy savings due to the possibility of using controlled cooling of steel semi-finished products directly after hot forming. The purpose of the research carried out in this work was to determine the rational modes of controlled cooling of forgings made of dispersion-hardening steels that provide the properties and microstructure required by the standard. For this purpose, a simulation simulation of the cooling of the forgings of the connecting rod of the KAMAZ car engine with the temperatures of the stamping end in various media (compressed air, water-air mixture, water, oil) was carried out, which made it possible to determine the composition of the medium (ratio) of water and air in the water-air environment and its supply modes providing cooling of forgings with speeds above critical, that is, without the formation of a ferritic mesh along grain boundaries during the decay of austenite. Subsequently, these modes were reproduced in laboratory and experimental-industrial conditions with the determination of the mechanical properties and microstructure of the steel of the connecting rod forgings. For 38MnVS6 steel, it has been established that controlled cooling from the stamping end temperatures not lower than 950 °C and the cooling rate not lower than 10 °C/sec, the properties and microstructure of forgings meet the requirements of the standard for connecting rods. This makes it possible to abandon the energy-intensive heat treatment (thermal improvement) of forgings provided for by the production technology.

1. Efron L. I., Morozov Yu. D. Investigation of the influence of controlled rolling modes on the microstructure and properties of microalloyed steels. Metallurg. 2018. No. 1. pp. 69–74.
2. Gubanov S. А, Chikishev D. N. Controlled rolling and accelerated controlled cooling in a plate mill for the production of pipe steels. Modelirovanie i razvitie prozessov OMD. 2014. No. 20. pp. 207–215.
3. Pater Z., Tomczak J., Bulzak T., Cyganek Z., Andrietti S. et al. An innovative method for producing balls from scrap rail heads. The International Journal of Advanced Manufacturing Technology. 2018. Vol. 97. No. 1–4. pp. 893–901.
4. Chen L., Bi K. Study on simulation experiment with universal pass rolling deformation for heavy rail. Advanced Materials Research. 2012. Vol. 430–432. pp. 525–529.
5. Hohenwarter A., Pippan R. Fracture of ECAP-deformed iron and the role of extrinsic toughening mechanism. Acta Materialia. 2013. Vol. 61. No. 8. pp. 2973–2983.
6. Gorelik S. S., Dobatkin S. V., Kaputkina L. М. Recrystallization of metals and alloys. Moscow: MISiS, 2005. 432 p.
7. Alekseeva Е. L., Ermakov B. S., Polikhandrov Е. L. Influence of heat treatment on the strength properties of precipitation hardening alloy EP 718. Izvestiya vysshikh uchebnykh zavedeniy. Tsvetnaya metallurgiya. 2021. Vol. 27. No. 6. pp. 31–39.
8. Astashchenko V. I., Shibakov V. G. Technological methods for controlling steel structure formation in the production of machine parts. Moscow: Асаdemia, 2006. 328 p.
9. Shibakov V. G., Astashchenko V. I., Soloveychik S. S. et. al. Heredity of macro- and microstructure in steel blanks of machine parts. International scientific collection "Equipment and technology for heat treatment of metals and alloys". Kharkov: KhFTI, 2007. pp. 117–122.
10. Khaysterkamp F., Khulka К., Matrosov Yu. I., Morozov Yu. D., Efron L. I. et. al. Niobium containing low alloy steels. Moscow: Intermet inzhiniring, 1999. 94 p.
11. Zhang Q., Zhang B., Li R., Ma L. Advances in theory and technology for microscopic surface quality control of steel strip. Journal of Mechanical Engineering. 2016. Vol. 52. Iss. 10. pp. 32–45.
12. Witold W. Aussteniete transformation kinetics of ferrous alloys. Grunwich: Climax Molibdenium Company, 2015. 84 p.
13. Umanskiy А. А., Dorofeev V. V., Dumova L. V. Development of theoretical foundations for energy-efficient production of railway rails with enhanced performance properties. Izvestiya vysshikh uchebnykh zavedeniy. Chernaya metallurgiya. 2020. Vol. 63. No. 5. pp. 318–326.
14. Umansky А. А., Golovatenko A. V., Temlyantsev M. V., Dorofeev V. V. Experimental studies of plasticity and deformation resistance of chromium rail steel. Chernye Metally. 2019. No. 6. pp. 24–28.
15. Shibakov V. G., Pankratov D. L., Shibakov R. V., Nizamov R. S. Features of the formation of service properties of gears obtained by precision stamping. Chernye Metally. 2020. No. 7. pp. 40–45.
16. GOST R 53813–2010. Automobile engines. Connecting rods. Technical requirements and test methods. Introduced: 15.09.2010. Moscow: Izdatelstvo standartov, 2010.
17. DIN EN 10267–1998. Ferritic-pearlitic steels for precipitation hardening from hot-working temperatures. Introduced: 01.02.1998. Moscow: Izdatelstvo standartov, 1998.
18. GOST 18895–97. Steel. Method of photoelectric spectral analysis. Introduced: 01.01.1998. Moscow: Izdatelstvo standartov, 1997.
19. Technical Specification 2149-097-10968286–99. BMF salt mixture for heat treatment. Specifications. Introduced: 30.12.1999. Moscow: Izdatelstvo standartov, 1999.
20. GOST 9012–59. Metals. Method of Brinell hardness measurement. Introduced: 01.01.1960. Moscow: Izdatelstvo standartov,
21. GOST 1497–84. Metals. Methods of tension test. Introduced: 01.01.1986. Moscow: Izdatelstvo standartov, 1984.
22. GOST 9454–78. Metals. Method for testing impact strength at low, room and high temperature. Introduced: 01.01.1979. Moscow: Izdatelstvo standartov, 1978.