Фундаментальные и прикладные проблемы черной металлургии

DOI: 10.52150/2522-9117-2025-39-14

A. Yu. Borysenko1, D. Sc. (Tech.), Senior Researcher, ORCID 0000-0003-2120-0944

O. E. Baranovska1,*, Ph. D. (Tech.), ORCID 0000-0002-4106-5797

1Iron and Steel Institute of Z.I. Nekrasov National Academy of Sciences of Ukraine, Academican Starodubova Square, 1, Dnipro, 49107, Ukraine

* Corresponding author: elena15dnepr@gmail.com

RESEARCH ON THE INFLUENCE OF TECHNOLOGICAL FACTORS OF PRODUCTION ON THE STRUCTURE AND HARDNESS OF CAST PISTON RINGS BLANKS MADE OF GRAY IRON

Abstract. The production of piston ring blanks from gray cast iron by the method of individual casting is complicated by the fact that the required structure of graphite and metal matrix is formed directly during the crystallization process without the use of heat treatment. In this regard, there is a need for strict control of both the chemical composition of the starting cast iron and the parameters of the casting process. The influence of overheating temperature, holding time and melt pouring temperature on the hardness and structure of cast blanks of compression piston rings of different sizes at a given chemical composition of cast iron (in wt.%) was assessed: C=3.72; Si=2.82; Mn=0.79; P=0.4; S=0.045; Ni=0.23; Cr=0.26; Cu=0.48; Mo=0.53; Ti=0.05. It is shown that fluctuations in the temperature of overheating and pouring of the melt within 10–50 °C and its holding time within 1–11 min. do not cause systemic changes in the hardness and microstructure of castings of ring blanks made of gray cast iron. The hardness along the blank rings is not uniform and is 94–112 HRB, which meets the requirements of GOST 621-87 “Piston rings for internal combustion engines”. It has been established that the structure of graphite and metal matrix of castings of ring blanks from gray cast iron, despite compliance with the technological process of their production, often does not meet the requirements of the specified standard. The maximum size of graphite inclusions is 120–250 μm, which exceeds the required size of 80 μm according to GOST 621. To achieve compliance with the requirements of GOST 621-87 regarding the structure of graphite and the metal matrix, as well as to prevent a decrease in hardness after heat treatment of cast ring blanks, it is necessary to reduce the maximum size of graphite inclusions to 80 microns and ensure the formation of dispersed pearlite with no more than 5% hypoeutectoid ferrite. To obtain the required graphite structure and metal matrix, it is important not only to maintain the stability of the casting process, but also to adjust the composition of the cast iron melt taking into account the content of gases (O, N, H). Their concentration is directly related to the origin of the charge materials, among which blast furnace iron and secondary metal from our own production are of primary importance.

Key words: gray cast iron, superheating temperature, pouring temperature, hardness, structure.

For citation: Borysenko, A. Yu., & Baranovska, O. E. (2025). Research on the influence of technological factors of production on the structure and hardness of cast piston rings blanks made of gray iron. Fundamental and applied problems of ferrous metallurgy, 39, 246-263. https://doi.org/10.52150/2522-9117-2025-39-14

References

  1. Hecht, R. L., Dinwiddie, R. B., & Wang, H. (1999). The effect of graphite flake morphology on the thermal diffusivity of gray cast irons used for automotive brake discs. Journal of Materials Science, 34(19), 4775–4781. http://doi.org/10.1023/a:1004643322951.
  2. Rukadikar, M. C., & Reddy, G. P. (1986). Influence of chemical composition and microstructure on thermal conductivity of alloyed pearlitic flake graphite cast irons. Journal of Materials Science, 21, 4403–4410. http://doi.org/10.1007/bf01106563.
  3. Wang, W., Jing, T., Gao, Y., Qiao, G., & Zhao, X. (2007). Properties of a gray cast iron with oriented graphite flakes. Journal of Materials Processing Technology, 182(1-3), 593–597. http://doi.org/10.1016/j.jmatprotec.2006.09.028.
  4. Hinrichs, R., Vasconcellos, M. A. Z., Österle, W., & Prietzel, C. (2018). Amorphization of Graphite Flakes in Gray Cast Iron Under Tribological Load. Materials Research, 21(4), 1–6. http://doi.org/10.1590/1980-5373-MR-2017-1000.
  5. Kumar, S., Kumar, P., & Shan, H. S. (2008). Optimation of Tensile Properties of Evaporative Casting Process through Taguchi’s Method. Journal of Materials Processing Technology, 204, 59–69. http://doi.org/10.1016/j.jmatprotec.2007.10.075.
  6.  Hong Nga Thi Pham (2020). Effect of Heat Retention Time and Pouring Temperature on Graphite Shape and Mechanical Properties of Gray Cast Iron. Advances in Science, Technology and Engineering Systems Journal, 6(5), 838–844. http://doi.org/10.25046/aj0506100.
  7. Huang, X., Ye, Y., Shen, X., & Chang, X. (2011). The mechanical properties of gray cast iron and metallographic structure effect on the chip shape. Advanced Materials Research, 339, 200–203. http://doi.org/10.4028/www.scientific.net/AMR.339.200.
  8. Svensson, I., & Sjögren, T. (2009). On Modeling and Simulation of Mechanical Properties of Cast Irons with Different Morphologies of Graphite. International Journal of Metal casting, 3(4), 67-73. http://doi.org/10.1007/BF03355460.
  9. Zapuskalov, N. (2004). Quality Improvement of Cast Strip by Temperature Treatment of Liquid Metal. ISIJ International, 9 (44), 1541–1548.
  10. Screbtsov, A. M. (2011). Optimalnye temperatury nagreva zhidkogo metalla v plavilnykh agregatakh. Dve temperatury splavov na osnove zheleza. [Optimum Heating Temperatures for Liquid Metal in Smelting Units. Two Temperatures for Iron-Based Alloys]. Casting processes, 1, 3-9. [In Ukrainian].
  11. Screbtsov, A. M. (2012). Temperatura likvidus metallicheskogo rasplava i ee vliianie na kolichestvo oksidnykh nemetallicheskikh vkliuchenii [Liquidus temperature of a metallic melt and its influence on the amount of oxide non-metallic inclusions]. Current problems of modern metallurgy. PDTU. 79–83. [In Ukrainian].
  12. Nuradynov A. S., Baranov I. R., & Prygunov S. V. (2024) Metodyka doslidzhennia zarodzhennia krystaliv u rozplavakh kraplynnym metodom. [Methodology for studying crystal nucleation in melts by the drop method]. Metallurgy and metal processing, 2, 27–35. [In Ukrainian].
  13. Melnykov A. P., Sadokya M. A., & Fonov V. V. (2011). Sovershenstvovanie tekhnologii i oborudovaniia dlia proizvodstva zagotovok porshnevykh koletc v vertikalnykh stopochnykh formakh.  [Improvement of technology and equipment for the production of piston ring blanks in vertical stack forms]. Casting and metallurgy, 4 (63), 18–22. [In Russian].
  14. Melnykov A. P., Golub D. M., & Fonov V. V. (2006). Vysokotekhnologichnoe oborudovanie dlia izgotovleniia vertikalno-stopochnykh form v proizvodstve otlivok porshnevykh koletc. [High-tech equipment for the production of vertical casting molds in the production of piston ring castings]. Casting and metallurgy,2(38), 51–54. [In Russian]
  15. Oyetunji, A., & Talabi, H. K. (2016). Effects of heat treatment process on mechanical and microstructural properties of gray cast iron. Acta Technica Corviniensis-Bulletin of Engineering, 9(4), 117–122.

Received  19.07.2025
Accepted 21.10.2025
Published online 01.12.2025

No widgets added. You can disable footer widget area in theme options - footer options

Фундаментальные и прикладные проблемы черной металлургии
Logo