## 4 Conclusions  
The study of C45 steel in plasma surfacing has limitations such as sensitivity in the heat-affected zone, the need for post-weld heat treatment, and the potential for cracking and distortion. Future research should focus on optimising welding and surfacing parameters, exploring advanced techniques, investigating alternative filler materials, and understanding the long-term performance of welded joints. Additionally, the use of simulations and environmentally friendly practices could enhance welding outcomes for C45 steel.  
Research into the plasma surfacing process reveals a significant influence of process parameters on the mechanical properties of the surface layers. Analysis of the results shows a relationship between microhardness and the mixing coefficient. It is observed that with increasing microhardness, the mixing ratio also increases. This trend may be the result of better integration of the surfacing layer with the substrate, resulting in increased durability and mechanical resistance of the resulting structure. Understanding the influence of  
Figure 7: Hardness dependence on plasma surfacing parameters.  
surfacing parameters on these properties is crucial for various applications where durability and wear resistance are important. This suggests that optimisation of process parameters can be an effective strategy in achieving the desired mechanical properties of surface layers.  
The plasma arc intensity has the greatest influence on the geometry of the coating and the mixing ratio. This confirms the importance of controlling this parameter in the process. However, further research is needed to more fully understand this relationship and further implications. Continued experimentation may provide more detailed information on optimal process parameter settings, which could lead to further improvements and innovations in plasma surfacing.  
Practical implications include the need for optimized plasma welding parameters and advanced techniques to ensure high-quality welds. Investigating alternative filler materials and understanding long-term performance are crucial for enhancing the reliability and durability of welded joints. Additionally, leveraging simulation tools and environmentally friendly practices can lead to more efficient and sustainable welding processes, ultimately broadening the applications of C45 steel in various industries. These results underscore the critical role of precise surfacing parameters in achieving desirable weld characteristics such as minimised dilution and enhanced hardness. Practical applications could benefit from these insights by optimising welding conditions to improve weld quality and durability in industrial settings. However, remaining questions persist, such as the long-term durability of surfaced materials under varying environmental conditions and the development of more sustainable welding practices. Addressing these gaps in future studies could further refine plasma welding techniques and broaden their applicability across diverse engineering applications.  
Data curation, S.B.; dermal analysis, S.B.; methodology, S.B. and R.S.; resources, S.B. and K.P.; software, S.B. and R.S.; supervision, S.B.; validation, S.B.; visualization, S.B.; writing--original draft, S.B.; writing--review and editing, S.B. and K.P. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.  
The authors declare no conflicts of interest.  
References