## 1 Introduction
Plasma surfacing with powder additive material requires greater control over temperature and gas parameters to maintain optimal melting conditions, while wire is more resistant to fluctuations in temperature and operating conditions [11]. The use of wire allows for more precise and controlled deposition of thin repair layers [12]. Plasma surfacing by using a plasma jet and a conductive filler wire is carried out using a direct current of simple polarity. The arc burns between the tungsten cathode and the filler wire, applied from the side at right angles to the plasma torch axis. A low intensity pilot arc (15-25 A) also burns continuously between the cathode and the plasma torch nozzle. The arc ensures reliable ignition and stable combustion of the main arc. The parent metal heats up under the heat of the plasma jet and the heat transferred by the secondary metal droplets. The effective heat output of this heat source depends on the arc current and the distance between the wire and the parent metal. By keeping the current constant and varying the current and thus the melting rate of the secondary wire, the power consumed to heat the parent metal can be varied over a relatively wide range. Thus, with plasma jet surfacing, it is possible to control the thermal and diffusion processes at the fusion edge, which determine the depth of penetration of the parent metal and the content of the parent metal in the metal, as well as the length, composition, and properties of the fusion zone [13]. Plasma jet deposition is widely used on ships for the deposition of corrosion-resistant and anti-friction alloys. The deposition of various shafts, equipment rods and other components is carried out using copper alloys with solid supplementary wires or powder wires. Argon is used as a plasma-forming gas and as a shield [14; 15]. Steel C45, also known as AISI 1045, is a medium carbon steel that is commonly chosen for plasma welding due to its specific properties that make it suitable for this kind of process. C45 steel has a carbon content of approximately 0.45%, which provides a good balance between hardness and ductility. This makes it easier to weld compared to high-carbon steels, which can be more prone to cracking. C45 can still be welded effectively with the proper techniques and precautions. Preheating and post-weld heat treatment are often employed to prevent issues such as cracking and to improve the overall quality of the weld. Compared to alloy steels or other high-performance materials, C45 steel is relatively cost-effective, making it a practical choice for many industrial applications [16]. The study [17] focused on the regularities of interfacial interactions, intermetallic phase formation (IMP) features, and defects during the surfacing of steels on titanium using four methods: P-MAG, CMT, indirect arc plasma surfacing with a conductive wire, and PAW. A general trend in the occurrence of IMPs in the surfacing of steels on titanium was found with all the methods considered. It was found that the plasma spraying technique using an indirect arc with a conductive wire was less critical with regard to IMP formation. The study showed the possibility of forming, in addition to TiFe2 and TiFe phases, a Ti2 Fe phase at low heat input. The indirect arc plasma surfacing technique with a conductive wire minimises the thermal effect on the base metal. When applied at the transition boundary of a titanium-lined steel layer, the phase composition and layer structure, in some cases, approach that of the transition zone of the original 'titanium-steel' bimetallic sheet produced by rolling. In the article [18], the method of multilayer plasma surfacing in an alloyed nitrogen shielding atmosphere was improved. The paper presents a comparative study of the residual stresses developed when surfacing with 3 Kh2V8, 4 Kh4V10 Yu, and R18 Yu steel wire. It is shown that the R18 Yu-based wire product provides the lowest residual stresses.