Siberian Federal University, Krasnoyarsk, Russia

T. R. Gilmanshina, Associate Professor, Candidate of Technical Sciences, e-mail: gtr1977@mail.ru
A. A. Kovaleva, Associate Professor, Candidate of Technical Sciences
I. A. Churuksaev, Master’s Student
N. S. Perfileva, Associate Professor, Candidate of Technical Sciences

The quality of standard gold ingots produced at OJSC Krastsvetmet depends on temperature, casting and solidification rate, and quality of molds. The latter operates under cyclic thermal effect, contributing to thermal stresses, oxidation, decarburization, erosion of operating surfaces and other defects. The currently available literature does not contain a clear opinion on prevai ling defects among the stated ones influencing failures of molds. The authors studied reasons for failures of molds manufactured from steel 40Kh13 and used for casting gold ingots from refined gold. The simulation showed that minor defects could be found on the surface of molds, if there were no serious defects. A main reason for failures of molds can be deemed a defect of erosion of the bottom determining non-compliance of ingots with GOST 28058–2015 in terms of their geometry. The study on the microstructure of original and used ingots showed that all the samples had a ferrite-troostite grain structure. A key difference in the structure of the used ingot is a size of grains of ferritetroostite areas and a ferrite/troostite ratio. This is explained by different hea ting of the mold: the sample shows an acicular structure in areas with higher temperature difference.

1. Krastsvetmet : official website. Available at: https://www.krastsvetmet.ru/www.krastsvetmet.ru/?ysclid=lu6nkshw3c290804290 (accessed: 04.08.2023).
2. Zadrutsky S. P., Nemenenok B. M. Production of castings from non-ferrous metal alloys. Minsk : BNTU, 2018. 56 p.
3. Zaitsev S. P., Dubrovin K. E. Encyclopedia of technologies. Moscow, 2019. 345 p.
4. Wang Z. et al. Research on the process of casting gold jewelry. Materials Science and Engineering: A. 2008. Vol. 485, Iss. 1. pp. 122–126.
5. Zhang X., Jiang X. Investigation of die-casting process for gold alloys. International Journal of Cast Metals Research. 2008. Vol. 20, Iss 4. pp. 302–309.
6. Yang Z., Fu H., Chen J. Investigation of die-casting process parameters for gold alloys. International Journal of Cast Metals Research. 2006. Vol. 18, Iss. 3. pp. 221–226.
7. Mike D. A. Gold ore processing: project development and operations. Singapore : Elsevier, 2016. 1020 p.
8. Yakovlev A. Yu., Volchok I. P. Materials for manufacturing metal molds. Lite i Metallurgiya. 2007. No. 4(44). pp. 118–121.
9. Milyaev A. F., Nikitin Yu. P., Kadnikov S. V., Timofeev V. A., Matveev A. N. Chemical composition of rolled iron unfluence for eyelashes durability. Theory and Technology of Metallurgical Production. 2014, Iss. 1. pp. 56–58.
10. Milyaev A. F., Nikitin Yu. P., Kadnikov S. V. et al. Influence of operation parameters on durability of molds from cupola iron. Theory and technology of metallurgical production. 2014. No. 2 (15). pp. 77–80.
11. Filippov A. S., Radya V. S., Mikhailova G. G. et al. Influence of operation modes on optimal geometrical parameters of molds. Stal. 1971. No. 1. p. 52.
12. Chernyak A. B. Operation and mature of failures of molds for producing secondary non-ferrous alloys. Materials and technologies in metallurgy. 2001. No. 1. pp. 46–48.
13. GOST 28058–2015. Gold in ingots. Introduced: 01.01.2017.
14. GOST 5632–2014. Stainless steels and corrosion resisting, heat-resisting and creep resisting alloys. Grades. Introduced: 01.01.2015.
15. GOST 5639–82. Steels and alloys. Methods for detection and determination of grain size. Introduced: 01.01.1983.
16. GOST 8233–56. Steel. Micro structure standards. Introduced: 01.07.1957.