Domestic food processing across West Africa depends on cast iron grinding wheels with a white iron surface layer containing a continuous cementite network for wear resistance and a grey iron core for structural support, yet these components suffer severe wear degradation. The wear coefficient evolution as a function of heat treatment temperature has not been quantified, nor has the friction-wear coupling mechanism been established, leaving manufacturers without guidance. Specimens from a locally manufactured wheel (3.35 wt% C, 1.80 wt% Si) were subjected to annealing, normalising, quenching, and tempering at 700°C, 750°C, and 800°C. Hardness was measured by Brinell testing, microstructures by optical microscopy, and wear performance by the Archard model with microstructure-dependent coefficients. The as-cast material exhibited 229 HBW, while all heat treatments reduced hardness; water quenching did not produce martensite due to 1.80 wt% Si limiting hardenability. Calculated mass loss increased from 250 mg to 310–3,400 mg for heat-treated conditions, representing up to 1,300% increase, as thermal energy promotes cementite decomposition. Heat treatment increases the wear coefficient by up to 830% and transitions wear from micro-cutting to ploughing. The as-cast condition provides 21-month estimated service life compare to 2 month for annealed wheels, representing a 14-fold annual cost reduction. Manufacturers should prioritise casting conditions over thermal processing. This study introduces the first microstructure-specific wear coefficient framework and economic life-cycle cost model for these wheels.

References

1. Adebayo, A. O., Taiwo, G. L., & Oyetunji, A. (2017). Effects of magnesium variation and heat treatment on mechanical and micro-structural properties of ductile cast iron. FUOYE Journal of Engineering and Technology, *2*(2).

2. Adeyemi, O. O., & Ogunniyi, O. O. (2019). Casting defects and their influence on the service performance of locally manufactured grinding plates. West African Journal of Foundry and Metallurgy, *4*(1), 45-58.

3. Adeyemo, T., Onyekachi, A., & Chukwudi, E. (2023). Cooling rate effects on the microstructure of cast iron components. West African Journal of Materials Science, *9*(2), 134-151.

4. ASTM E10-18. (2018). Standard test method for Brinell hardness of metallic materials. ASTM International, West Conshohocken, PA.

5. ASTM E140-12b. (2012). Standard hardness conversion tables for metals relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Superficial hardness, Knoop hardness, Scleroscope hardness, and Leeb hardness. ASTM International, West Conshohocken, PA.

6. ASTM E562-19. (2019). Standard test method for determining volume fraction by systematic manual point count. ASTM International, West Conshohocken, PA.

7. ASTM G65-16. (2016). Standard test method for measuring abrasion using the dry sand/rubber wheel apparatus. ASTM International, West Conshohocken, PA.

8. Busari, Y. O., Adebisi, J. A., Shuaib-Babata, Y. L., Amuzat, L. O., & Babamale, H. F. (2021). Effect of ferrochrome addition on wear and hardness properties of grey cast iron. Mindanao Journal of Science and Technology, *19*(2), 45-58.

9. Darmawan, A. S., Yulianto, A., Febriantoko, B. W., Masyrukan, Ginta, T. L., & Hamid, A. (2025). Engineering hardness and toughness of gray cast iron with the addition of silicon elements. Journal of Physics: Conference Series, *2972*(1), 012042. https://doi.org/10.1088/1742-6596/2972/1/012042

10. Doğan, O. N., & Hawk, J. A. (2001). Abrasion resistance of high chromium white irons. Journal of Materials Science, *36*(10), 2463-2473. https://doi.org/10.1023/A:1017963703610

11. EN 1186-1:2002. (2002). Materials and articles in contact with foodstuffs - Plastics - Part 1: Guide to the selection of conditions and test methods for overall migration. European Committee for Standardization, Brussels.

12. EN 12513:2011. (2011). Founding - Abrasion-resistant cast irons. European Committee for Standardization, Brussels. Journal

13. Kaboli, K., Mostafapour, M., Kheirkhahan, N., Edalati, E., Solbi, E., Babakhani, A., & Kiani Rashid, A. R. (2025). Revisiting the effect of casting thickness and austempering temperature of gray iron. of Materials Engineering and Performance, *34*(14), 14167-14179. https://doi.org/10.1007/s11665-024-09999-9

14. Kibble, K. A., & Pearce, J. T. (2023). The effect of heat treatments on the properties of a ferritic high-chromium cast iron. Journal of Materials Engineering and Performance, *32*, 8262-8273. https://doi.org/10.1007/s11665-023-08099-4

15. Kostyleva, L. V., Gapich, D. S., Novikov, A. E., & Motorin, V. A. (2019). Variation of the composition and properties of cementite in heat treatment of tilling machine members from chilled cast iron. Metal Science and Heat Treatment, *61*(3-4), 205-210. https://doi.org/10.1007/s11041 019-00401-6

16. Kutelu, B. J., Oluyori, R. T., & Omoyeni, D. O. (2024). Microstructure characteristics and mechanical properties of grey cast iron at varied ferrosilicon addition. ABUAD Journal of Engineering Research and Development, *7*(2), 290-296.

17. Kwofie, S., & Chandler, H. D. (2016). Potential health effects of locally-manufactured corn-mill grinding plates. Journal of Science and Technology, *26*(2), 45-58.

18. Laird, G., Gundlach, R., & Röhrig, K. (2000). Abrasion-resistant cast iron handbook. American Foundry Society, Des Plaines, IL

.19. MEDID. (2025). Metal grinding discs for cast iron and steel [Product specifications]. MEDID Sp. z o.o. https://medid.pl/en/22-metal-grinding-discs

20. Ochulor, E. F., Adeosun, S. O., Kareem, A. J., & Ashade, A. I. (2023). Effects of annealing soaking time on carbide precipitates and mechanical properties of as-cast thin wall ductile iron. ABUAD Journal of Engineering Research and Development, *6*(2), 230-238.

21. Oke, S. R., & Ige, O. O. (2018). Assessment of locally fabricated grinding plates in Nigeria. Nigerian Journal of Technology, *37*(3), 678-685.

22. Omotoyinbo, J. A., & Oluwole, O. O. (2022). Corrosion behaviour of grinding discs in simulated gastro-intestinal environments. Journal of Materials and Corrosion, *73*(4), 567-578.

23. Oyewole, O. A., & Adebayo, A. A. (2020). Metallic contaminants in traditionally processed foods in Southwest Nigeria. Journal of Food Safety and Hygiene, *6*(3), 89-101.

24. Tabrett, C. P., Sare, I. R., & Ghomashchi, M. R. (1996). Microstructure-property relationships in high chromium white iron alloys. International Materials Reviews, *41*(2), 59-82. https://doi.org/10.1179/095066096790151195

25. Taiwo, F., Oyediran, O., & Akinwale, O. (2024). Influence of cooling rates on cast iron structure. Journal of Foundry and Casting Technology, *27*(3), 145-162.

26. Terngu, A., Agboola, O. F., & Garba, D. K. (2023). Model for prediction of some mechanical properties of ductile cast iron austempered in Jatropha curcas seed oil. Arid Zone Journal of Engineering, Technology and Environment, *19*(2), 203-210.

27. U.S. Food and Drug Administration. (2017). Food Code 2017: Chapter 4 - Equipment, utensils, and linens. U.S. Department of Health and Human Services, Washington, DC.

28. Widder, L., Rojacz, H., Buscher, M., & Varga, M. (2021). High-temperature abrasion resistance and wear mechanisms of chilled high-chromium cast irons. IOP Conference Series: Materials Science and Engineering, *1140*(1), 012027. https://doi.org/10.1088/1757-899X/1140/1/012027

29. Wilk, O. S., & Halle, T. (2023). Gruson's chilled cast iron - A legendary wonder material of the 19th century. Practical Metallurgy, *60*(12), 796-819. https://doi.org/10.1515/pm-2023-1046