PSI - Issue 43

Miroslav Polášek et al. / Procedia Structural Integrity 43 (2023) 306–311 Author name / Structural Integrity Procedia 00 (2022) 000 – 000

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When comparing the friction surfaces of both experimental materials, we observe that with a turning radius of 30 mm. (Fig. 5a) the width of the friction path was lower than at a higher cooling rate (Fig. 5c). The same results were obtained for both types of materials. As the rotation diameter increases, so does the rotation speed. The results show that as the speed increases due to the decreasing roughness of the materials, the wear increases. This consequence is due to the fact that at a roughness Sa 12.5, the contact ball moves only along the protrusions of the surface of the materials and thus is not inhibited by touching the entire surface of the sample. As the roughness decreases, this wear increases due to the contact of the larger friction surface. When comparing the friction surface, we observe that at the surface roughness Sa 12.5 and Sa 6.3 the values are very similar. At the lowest material roughness, 42CrMo4 proved to be the better wear material. The wear is broken in Fig. 5f (42CrMo4) and Fig. 5c (30CrNiMo8). We observe that the 42CrMo4 material showed more than a 50% reduction in wear due to the width of the friction surface. Conclusion In this study, the tribological properties of two experimental steels 30CrNiMo8 and 42CrMo4, which are planned to be used as the main production, were compared. The experimental materials were in contact with a G40 steel ball in the form of bearing balls. Both materials were also heat treated. The whole tribological experiment was performed at room temperature 22 °C, without the use of lubricant and at a constant load of 2.5 N. In presenting the results, the authors focused on the evaluation of COF and the comparison of wear at different surface roughness. Both experimental materials underwent adhesive wear. Due to the final roughness, the material 42CrMo4 proved to be a better material at roughness Sa 3.6. It showed more than 50% lower wear values compared to 30CrNiMo8. Acknowledgements This work was also supported by the Research Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic under the contract (ITMS2014+) no. 313011W442-CEDITEK II. References Gehlen, S., Neis, D., Barros, Y., Poletto, C., Ebeling, M., Ferreira, N. Angrizani, C., 2020. Tribological behavior of glass/sisal fiber reinforced polyester composites, in: Polymer Composites , 41 (1), pp. 112-120. Budinski, G., Budinski, T., 2021. Tribology, Tribosystems, and Related Terminology. Krbaťa, M., Majerík, J., Barényi, I., Mikušová, I., Kusmič, D., 2019. Mechanical and tribological features of the 90MnCrV8 st eel after plasma nitriding, In: Manufacturing Technology 19 , pp. 238-242. Drozd, K., Walczak, M., Szala, M., Gancarczyk, K., 2020. Tribological behavior of AlCrSiN-coated tool steel K340 versus popular tool steel grades, in: Materials 13 (21), pp. 4895. Gao, Y., Jiang, Y., Jiang, H., Zeng, S., Guo, F., Li, J., 2019. Cholesterol ester derivatives as oil-based lubricant additives: mesogenic and tribological properties, in: Materials Research Express 6 (12), pp. 125106. Yuan, Z., He, Y., Cheng, K., Duan, Z., Wang, L., 2019. Effect of self-developed graphene lubricant on tribological behaviour of silicon carbide/silicon nitride interface, in: Ceramics International 45 (8), pp.10211-10222. Wu, B., Chen, G., Xia, W., 2008. Heat transfer in a 155 mm compound gun barrel with full length integral midwall cooling channels, in: Applied Thermal Engineering 28 (8-9), pp. 881-888. Chen, J., Wang, W., Jin, P., Dou, C., Zhao, C., Li, Q., Huang, J., 2022. Thermo-mechanical analysis of strength degradation of 30SiMn2MoVA gun barrel material during continuous shooting, in: Engineering Failure Analysis , pp. 106438. Sequard-Base, J., Haas, R., Tomastik, C., Vernes, A., Franek, F., 2018. Barrel friction in sport rifles, in: Tribology Letters 66 (1), pp. 1-10. Lawrence, D., Miller, R., Robertson, R., Singh, B., Nagarkar, V., 2016. High frame-rate real-time x-ray imaging of in situ high-velocity rifle bullets, in: Anomaly Detection and Imaging with X-Rays Vol. 9847, pp. 98470G. Kim, J., Kim, J., 2021. Analysis of Probability Distribution of Muzzle Velocity for Chrome Plated Barrel, in: Journal of the Korea Institute of Military Science and Technology 24 (4), pp. 401-407.