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This paper examines the detection of internal defects in composite specimens composed of Onyx, a material featuring a nylon matrix reinforced with chopped carbon fibers. Artificial defects, in the form of flat-bottom holes of various geometries, were intentionally introduced during the additive manufac-turing process. The primary objective is to determine the depth detection capabilities of ultrasound by varying the excitation frequency and determining whether these defects remain identifiable at different subsurface levels. Ultrasonic lock-in thermography is utilized to excite specimens. As the frequency is modified, the depth of wave propagation also changes, a phenomenon well established in homogene-ous materials. However, the heterogeneous nature of Onyx introduces complexities into wave propa-gation. The recorded thermographic data are processed in MATLAB to calculate contrast ratio values, enabling a quantitative comparison of defect detectability for different defect geometries.

This article presents the research findings on the flow behaviour of thermoplastic resin in foam core sandwich composites for aerospace applications during the vacuum assisted infusion process. After optimizing the process parameters, two sandwich panels were manufactured using glass fibre fabrics, a polymethacrylimide (PMI) foam core, and a liquid acrylic resin. To compare the sandwich and monolithic structure process behaviour, a monolithic composite panel was also manufactured. By combining experimental monitoring with Darcy's law, permeability differences between the structures were evaluated. The results indicate that PMI foam does not significantly affect the resin flow trend, and that Darcy´s law can be applied to both monolithic and sandwich structures when a thermoplastic liquid resin is used. These findings offer theoretical guidance for process parameter design and real-time in situ monitoring of the vacuum infusion process.

The effect of the nitrocarburizing process in pastes with heating in a chamber furnace on the struc-ture and strength characteristics of 09Cr15Ni8Al corrosion-resistant steel was investigated. The tech-nology of chemical-thermal treatment was developed, which included nitrocarburizing in pastes with heating in a chamber furnace at different holding times. The thickness of the diffusion layer and its microhardness were determined after nitrocarburizing. To determine the efficiency and select the modes of chemical-thermal treatment, tests were carried out for the investigated steel's strength characteristics. The main feature of the structure of the diffusion layers of valve steels, obtained by nitrocarburizing in the nitrogen-carbon paste, is the presence of an inhomogeneous layer with clearly distinguished zones.

This study experimentally compares how three common machining routes, turning, milling and grinding, affect the surface texture and tribological response of three structural steels (C45, 42CrMo4, 30CrMoV9) under conditions where the profile roughness Ra is deliberately aligned across routes. Areal topography was measured by coherence correlation interferometry and evaluated according to ISO 25178 (height metrics Sa, Sq, Sp, Sv, Sz, St). The bearing area curve (Abbott–Firestone) was used to derive functional descriptors Rpk, Rk and Rvk. Scratch resistance was determined on a UMT‑3 tribometer (Rockwell 120°, P = 50 N) as HSp = 8·P / w² in accordance with ASTM G171. The results show that surfaces with comparable Ra can differ markedly in areal extremes and BAC‑derived parameters, which is reflected in scratch response. These findings support replacing sole Ra specification with areal and bearing‑curve descriptors when functional performance is critical (friction, sealing, wear).

This study examines the influence of FDM printing parameters on replica parts for an educational robotics kit, targeting functional compatibility without post-processing. A VEX Robotics 2×12 Beam (228‑2500‑026) was used as the reference part. Reference dimensions were obtained as mean values from 10 original VEX IQ parts. Replicas were printed from PLA and PETG on Original Prusa MK4 printers using four infill patterns and six infill densities (15–70%). For each material–pattern–density combination, 10 parts were produced, resulting in 480 printed samples. Width, length, and height were measured with a Mitutoyo MiSTAR 555 CNC CMM in accordance with ISO 10360-2. Results are expressed as mean deviations from reference dimensions, standard deviations, and expanded uncertainty of the mean. Maximum deviations reached 0.062, 0.092, and 0.032 mm for PLA, and 0.046, 0.090, and 0.028 mm for PETG. The results provide guidance for selecting non-solid infill settings that reduce material use and printing time while maintaining dimensional compatibility

An agricultural tractor equipped with appropriately rated guards can often replace specialized forestry machinery. Currently, few authorized dealers on the Polish market offer tractors adapted to harsh forest conditions, so this work involved designing a tubular guard for the Kubota M135GX-VI agricul-tural tractor. The aim of this work was to develop a conceptual design for a tubular guard, together with a strength analysis based on FOPS procedures, dedicated to the KUBOTA M135GX-IV agricul-tural tractor. To properly design the tubular guard, applicable standards and regulations regarding the construction of cabs and tubular guards for agricultural and forestry machinery were first analyzed. Subsequently, the available solutions were analyzed and two original concepts were developed. These concepts were evaluated based on the adopted criteria, selecting the variant with the highest score. Furthermore, the most advantageous variant was subjected to a strength analysis using the finite el-ement method (FEM) in accordance with the FOPS procedure. The test results showed that all nodes included in the developed concept met the strength requirements.

Cobalt-based alloys are widely used for orthopedic implants due to their excellent mechanical properties and corrosion resistance. Biomedical Co-Cr-Mo alloy, commonly applied in knee replacements, is typically produced by precision casting. However, in cases requiring patient-specific geometries, additive manufacturing technologies, such as Selective Laser Melting (SLM), offer promising alternatives. This study compares the microstructure and mechanical properties of Co-Cr-Mo alloy in the as-cast state and after SLM processing. The SLM-produced samples exhibited a fine, cellular microstructure and superior mechanical strength. Specifically, the printed alloy achieved a yield strength of 688 ± 8 MPa and an ultimate tensile strength of 994 ± 11 MPa, exceeding that of the cast material by about 495 ± 1 MPa. These results demonstrate the potential of SLM technology for manufacturing customized orthopedic implants with improved mechanical properties and dimensional accuracy.

The article presents the results of the use of quality instruments – tools and techniques – in order to reduce surface defects of steel structures on the example of a selected element – engine cover of asphalt milling machines. The article shows the potential of using selected quality tools – basic and new – in the service of quality analysis and improvement. Quantitative analyzes were presented out using the Pareto-Lorenz diagram and the c control chart, qualitative analyzes using the Ishikawa diagram and the FMEA method, quantitative & qualitative analyzes using the interrelationship diagram and matrix diagram, and it was proposed quality improvement using qualitative tools such as affinity diagram, and PDPC diagram. The most common defects of painted surfaces turned out to be improper thickness and surface contamination. As it has been shown, the experience of employees is largely responsible for the cause of these defects, which was also confirmed by other analyses carried out with the use of quality tools. The training was the most frequent method of prevention. It has also been shown that special attention should be paid to quality control, its effectiveness, and quantity. The article proves that correctly used quality tools can contribute to the improvement of the quality of manufactured products, helps in solving various quality problems.

The surface created by machining significantly affects the service life and functional reliability of the component. As part of this study, four different chip machining technologies were evaluated on the surface texture of the polymer material Ertacetal C. The samples were processed by turning, milling, grinding and polishing technologies, 5 samples for each technology. Within the given technology, different cutting conditions were chosen to compare the effect of cutting conditions on the resulting surface roughness. The machined surfaces were comprehensively evaluated on the basis of 16 profile and surface roughness parameters due to the practical use of the tested material. Surface texture measurements were performed on a Talysurf CCI Lite device. A non-contact method using a coher-ence correlation interferometer was used for the measurement. The obtained data were evaluated using TalyMap Platinum software. Graphical documentation of the machined surfaces was made using an Olympus DSX500 opto-digital metallographic microscope.

The electrochemical discharge machining (ECDM) process is developing into a potentially useful method of performing micromachining in conductive or non-conductive materials. The materials are machined using a combination of chemical and thermal energy. This paper examines the effect of Artificial Neural Network (ANN) architectures combined with particle swarm optimization (PSO) on the predictive ability of tungsten carbide machining. Material removal rate (MRR) and surface roughness (SR) is the response used to evaluate the performance of the ECDM process. The four selected process parameters are voltage, gap width, electrode type, and type of electrolyte, with each parameter has two levels. The 4-9-1 structure was chosen to obtain pre-dictions in the form of an optimal formula based on the statistical values for surface roughness: MSE 0.001, RMSE 0.025, MAPE 1.36, and R2 0.99.

It is well known that the porosity of a product can have a negative effect on the mechanical properties of the product. For this reason, its control is very important. Porosity can be assessed by two methods - destructive and nondestructive inspection. However, the identification of very small pores is still very difficult for metallic materials, as the pore size may be below the resolution of most commonly used NDT techniques. In addition, different types of pores may be present in a single part, with one type usually dominating. Proper identification of porosity is essential to estimate the impact on structural properties. For pore assessment, as for other defects, the description of the morphology, distribution and frequency is important. This article deals with the comparison of methods designed to determine the porosity of products that have been manufactured using Laser Directed Energy Deposition – L-DED additive process. The samples were made from AISI 316L stainless steel. The porosity of these samples was assessed using destructive and nondestructive methods. Subsequently, their comparison was made in relation to the detection of different pore sizes. The samples were subsequently subjected to the HIP process (Hot Isostatic Pressing). For these samples, the changes that occurred in the material as a result of this process were subsequently quantified. This process should have a positive effect on improving the quality of the product produced by AM technologies, e.g. by reducing the number and size of pores.

The article deals with the measurement of the vibrations in passenger elevators. The introduction of an article briefly discusses machine vibrations and their impact on machine design and the surrounding environment. The basic equations from which the equations of motion are derived are listed here. The importance of analyzing machine vibrations in their design, or rather proposing solutions to reduce vi-brations during machine reconstruction, is emphasized. Specifically, attention is paid to vibrations gen-erated during an elevator operation in the elevator shaft. This is an elevator for transporting people in a newly constructed 5-story building. Vibration values generated by an elevator operation were measured in order to assess the suitability of simple anti-vibration modifications. Vibration measurements were taken on an existing elevator without modifications, and after the initial measurements, modifications were made to attach the guides to the bracket and attach the bracket to the elevator shaft wall. After the adjustment, the vibration measurement was performed again and both measurements were compared with each other.

In response to the problems of insufficient strength and stiffness, as well as large weight in traditional car frames, this article takes titanium alloy frames as the research object. Based on the analysis of static and dynamic characteristics, a lightweight design is carried out to meet the design requirements. Firstly, static analysis was conducted on the frame structure under four different working conditions using the finite element analysis method to study its stress distribution and deformation under different loads and road conditions. Study the natural frequency and vibration mode of the frame through modal analysis, providing a basis for subsequent optimization design. Through harmonic response analysis, explore the changes in the amplitude and frequency of the frame during use. On this basis, topology optimization and lightweight design are carried out on the frame structure to reduce the weight of the frame and improve its strength and stiffness. Finally, validate and compare the optimized frame to explore the feasibility and superiority of the optimization plan. The research results show that the optimized frame weight has been reduced by 13.76%, the maximum stress has been reduced by 5.19%, and the maximum deformation has been reduced by 0.37%, effectively reducing the frame mass. This provides a way of thinking about the static and dynamic characteristics analysis and topology optimization design of automotive frames.

The materials used in VVER nuclear power plants are subject to thermal ageing in operation, among other degradation mechanisms. The aim of the experiment was to verify the effect of thermal ageing on the change of ultrasound velocity on the extracted parts of main circulation piping and pressurizer surge line made of austenitic steels. Two steel conditions were evaluated, as received and thermally aged. The research was carried out on samples made from non-operated pipelines and samples from pipelines after 28 years of operation. The samples were subjected to thermal ageing at 450 °C in an atmospheric furnace with a specified exposure time to simulate extended operation of the compo-nent for 60 years, where 1 year of operation means 10 months at 100 %-unit power and 2 months in shutdown. The samples were subjected to ultrasonic property measurements and the longitudinal and transverse wave velocities obtained are further used to calculate the Poisson's constant and elastic modulus E of the material. To verify the ultrasonic measurements, the samples were also subjected to mechanical tests to verify the changes in the mechanical properties in terms of elastic behaviour of the selected steels when subjected to a static 3-point flexural test and Electron backscatter diffraction analysis (EBSD).

This study centers on 7B50 aluminium alloy. The intention is to reduce the pre-treatment and post-treatment times of the shot peening model. By comparing and analyzing different process parameters, the best combination of peening solutions can be obtained. The pre-processing is implemented through a GUI interactive interface. Post-processing is carried out by using Python for secondary development in ABAQUS. Orthogonal test method is employed for post-processing analysis of shot peening simulations under various process conditions. The results are evaluated by using a weighted composite scoring method to determine the depth of the residual compressive stress layer on the workpiece surface, the surface residual compressive stress, and the extreme deviation of the maximum residual compressive stress value after shot peening. The combined influence degree of shot peening process parameters such as impact speed, projectile diameter and impact angle is determined. The optimal combination of shot peening process parameters is analyzed and verified through simulation.

The article describes the creation of a mathematical 3D model of the original hovercraft structure, which will be further used for research into modifying the shapes and materials of the structure to ensure better driving conditions. Proposals for new materials for individual parts of the hovercraft structure will be addressed in order to reduce the weight of the hovercraft and thereby ensure a higher possible speed of movement, reduce fuel consumption and ensure the necessary mechanical properties of individual segments. The mathematical model of the simplified hovercraft model was created in the Cradle and Adams simulation programs. The paper is presented by analyzing the hovercraft properties in order to obtain sets of advantages and disadvantages of the hovercraft. The following is a description of the creation of a geometric 3D model of the hovercraft, which is built using Autodesk Inventor. The article further describes the transformation of the 3D model into a simulation model that can be used for co-simulation of movement in the Adams and Cradle computer simulation systems. The simulations will be the first step towards modifying the structure of a real rescue UAV prototype with improved maneuverability, stability and the ability to traverse terrain with surfaces unsuitable for hovering.

The magnitude of a locomotive's traction and braking forces is directly related to its adhesive mass, which largely determines its tractive and braking characteristics. Therefore, an important task is to maximize the utilization of the locomotive's adhesive mass. The degree of adhesive mass utilization is determined by more factors and is quantitatively characterized by the Adhesive Mass Utilization Coeffi-cient (AMUC). One of the ways to increase the AMUC is to improve the locomotive's lever-type brake transmission. In braking mode, it interacts with the wheelsets and the bogie frame and may block the operation of the first stage of the suspension system. This research presents the results of a mathematical model-based study of the influence of certain parameters of the lever brake transmission on the utilisation of locomotive adhesive mass in braking mode. The calculations were carried out for various values of the vertical stiffness of the brake transmission. The results indicate that the distribution of vertical loads across the locomotive's wheelsets in braking mode significantly depends on the vertical stiffness of the brake transmission.

The article is focused on the investigation of the impact of the implementation of mechanization into the welding workplace, for the production of cylinders from austenitic X5CrNi18 10 chromium nickel steel. The welds are assembled into a production line for the processing of puff pastry. In addition to the technical improvement of the process and the verification of the sufficient quality of the welds, calculations were used to prove that after the implementation of the change, there was a significant reduction in the production time. By introducing a higher level of mechanization and necessary technological changes, the production time was reduced by up to half, compared with the original technological procedure, including an increase in quality parameters and it led to a reduction in the production costs of the welding workplace. A significant consequence of the proposed change was connected with its impact on workplace safety.

Today, considerable attention is paid to the production of solid castings (approx. 2000 kg) from cast iron with spheroidal graphite. The metallurgical preparation of large quantities of melt is very difficult. This difficulty is related not only to the melting and preparation of large quantities of melt, but above all to its metallurgical treatment - inoculation and modification. Melt modification ensures the production of cast iron with spheroidal graphite. Material castings, such as machine tool components, cannot be destroyed to determine the quality of the cast iron produced. Therefore, this paper outlines a methodology to proceed in determining the quality of manufactured castings. It is possible to observe the chemical composition of cast iron, thermal analysis of cast iron using liquidus temperature value, subcooling temperature, eutectic recalescence, primary solidification recalescence, eutectic solidification time. Furthermore, to observe the mechanical values of cast iron (yield strength, ultimate strength and ductility) on fabricated bars of overmolded Y blocks or to observe the micro-structure of cast iron on microscope.

The development and characterizing of thin layers of AgCu, Cu, Ti, and Zr on nylon filters using PVD magnetron sputtering technology was conducted. The evaluation of these thin layers was mainly focused on characterizing specific parameters that may influence the expected functionality of the modified filter materials. The surface treatment of nylon filters with thin layers does not significantly affect the mechanical properties of the original nylon material. Thin layers deposited at a power of 0.9 kW exhibited greater thickness and lower static friction coefficient values than the layers deposited at 0.4 kW, except for a thin layer of the element titanium. The surface modification of the filters did not significantly change resistance to deformation and had no significant reduction in pore size. However, a significant effect on surface wettability (increased hydrophobicity) was demonstrated.

Biodegradable zinc-based alloys have recently attracted attention as promising candidates for temporary implant applications due to their favourable corrosion behaviour and biocompatibility. In this study, three materials — pure Zn, Zn–1Mg alloy, and a Zn + Zn–1Mg composite — were fabricated via powder metallurgy and extrusion to evaluate their microstructural characteristics and tensile performance. The composite material was designed to combine ductile Zn regions with a reinforcing Zn–1Mg network, aiming to achieve a balance of strength and ductility. Microstructural analysis revealed coarse-grained Zn regions surrounded by ultrafine-grained Zn–1Mg areas containing Mg₂Zn₁₁ particles, with oxide shells present at the Zn/Zn–1Mg interfaces. Tensile testing showed improvement in mechanical performance compared to the individual constituents. However, the oxide shells prevented effective load transfer between the fine-grained and coarse-grained areas of the microstructure.

Determining the productivity and quality of precision AWJ machining requires routine and careful inspection of nozzle condition. The degradation of the inner bore of the nozzle adversely impacts the mixing efficiency and uniformity of the water jet, thereby affecting its cutting performance. In this study, new nozzle was designed and manufactured using additive manufacturing and were made of 316 L stainless steel. The new nozzle consists of two combined parts with the peculiarity of being easy to install using a screw thread. The wear behavior of the new nozzle was examined using an accelerat-ed wear test. An accelerated wear test was conducted on the hard abrasive silicon carbide (SiC) and compared to garnet, the abrasive commonly used in the AWJ industry. The aim of the test was to de-termine the wear pattern of the nozzle. The cumulative mass loss and nozzle diameter increase for different abrasives were measured. The geometric change in the nozzle is made visible through de-structive examination. The findings indicated that the type of abrasives significantly affects nozzle wear. As the hardness of the abrasive increases, the diameter of the nozzle enlarges, resulting in accel-erated nozzle wear. The mass loss factor of SiC abrasives is three times higher than that of garnet abrasives. This research allows practitioners to monitor the nozzle wear behaviour during the AWJ process. The results obtained were used to estimate the nozzle life based on the observed wear history.

The effective application of additively manufactured materials requires accurate identification of their mechanical properties as well as damage mechanisms. Computer vision offers a novel approach for non-contact measurements, enabling the identification of selected mechanical properties. This paper presents a new method based on image analysis and the detection of circular markers for non-contact displacement measurements. The core principle involves detecting the centers of gravity of the circular markers formed on the sample under investigation. The centers of gravity are evaluated on each image created during the tensile test, representing nodal points. At these points, displacements are determined based on the non-contact extensometer. The deformations sought are a function of the displacements at each nodal point. These values were calculated based on several theoretical models, also used in the finite element analysis. The paper describes the computational procedure for determining the deformations based on the mentioned theoretical models. Subsequently, the total strain field is determined using linear interpolation of the displacement values at the individual nodal points. The results provided by each of the theoretical models were compared.

The optimization of process parameters plays a critical role in controlling temperature and velocity fields during centrifugal casting, which is essential for mitigating shrinkage porosity defects caused by uneven cooling in thick walled bearing alloy layers. In this study, two sequential numerical models were devel-oped using ProCAST software to simulate gravity filling and centrifugal solidification stages. The effects of key parameters, including inlet cross-sectional area and centrifugal rotational speed, on flow field characteristics were systematically analyzed. By using an orthogonal experimental design, we deter-mined the optimal parameters: a melt temperature of 440 °C for the Babbitt alloy, an initial temperature of 280 °C for the bearing blank, a filling inlet diameter of 16 mm, and a rotational speed of 340 r/min. Bearing alloy layers manufactured according to these optimized parameters exhibit no evident shrinkage or cracks on their surfaces. The high quality finished products meet the design requirements, thereby validating the accuracy of the numerical simulation.

There are many drawbacks and inconveniences in the application of human power in the energy meter calibration line. In order to achieve a standardized level of operation and to improve the efficiency and quality of the automated meter testing line, this paper applies the intelligent inspection robot to the automated meter testing line and discusses the key technologies involved. Based on the texture characteristics of the screws on the energy meter cover, a screw coordinate positioning method based on the texture center of gravity method is designed as a machine vision technique for intelligent inspection robots. Based on the feedforward controller transfer function and feedback system open-loop transfer function, combined with PI controller, a feedforward-feedback composite servo position control strategy is designed to complete the release action of the robot end controller. Pressure sensor on the robot end claw controller, integrated servo drive with current sensor. The Kalman filter method of static estimation is used to fuse and process multi-source data information to realize the grasping action of the robot end controller. The test results of the key technical performance and economic and time benefits of the robot show that the recognition success rate and grasping success rate of the robot for energy meters are as high as 100%, and it takes a total of 54s to complete each grasping and releasing action. The maximum error in each direction is 4.9mm, 5.2mm and 5.1mm respectively, and the maximum error in angle is only 1.25 degrees. The working manpower is reduced by as much as 93.16%, the average expenditure of inspection cost is only 1.24 yuan, and the floor space is reduced to 700 square meters. In summary, the study can ensure a high level of consistency in the quality of energy meters, improve the efficiency of calibration and production, and create greater economic benefits while providing a solid technical guarantee for the large-scale construction and stable and reliable operation of the power grid.

In this study, the microstructure of surface layers with varying roughness (Ra parameters) was analyzed using scanning electron microscopy (SEM) to optimize tribological properties in engineering design. SEM revealed key microstructural features – sharp and mild protrusions, pitting, microcracks and contaminants – that were not available in traditional profilometry. Reducing the Ra value improved surface uniformity by reducing irregularities and defect lengths, which had a positive effect on tribological properties and surface durability. However, defects were still present even at Ra < 1.25 μm, indicating the "Law of Microstructural Roughness," which emphasizes the inevitability of surface irregularities despite minimizing roughness. The integration of SEM results with profilometric methods enabled comprehensive identification and assessment of defects, combining microstructure with tribological properties. Results suggest that controlled roughness is key in combining materials and optimizing functional surfaces, particularly in the aerospace, biomedical and automotive industries, where reliability under demanding operating conditions is a priority.

Workpiece fabrication of titanium alloy is widely used in several high-end fields. In this study, finite element analysis of titanium alloy turning process is carried out and the turning process is modeled by using material properties and intrinsic equations. Then the power transmission of centerless lathe is controlled in the machining process, so as to obtain the performance calculation of different process parameters on cutting force, chips, and residual stress. The analysis of the simulation and experimental data yielded that when the tool travel speed was 1 m/min, the radial force increased to a maximum value of 150N. When the depth of cut was 0.3mm, the radial force was 151N and then increased to 200N. In the comparison of the simulation results, it was concluded that the depth of cut was 0.3mm, the minimum error value was 7.43%. In the quality analysis, the optimum parameters for travel speed and depth of cut were 1.0 m/min and 0.2mm respectively. When the spindle speed was 480 r/min, the roughness of the machined surface of titanium alloy was closer to the simulation results, and the lowest difference was 0.1 μm. Therefore, the finite element machining model of titanium alloy turning proposed by the study could effectively improve the machining quality and accuracy, and it has superiority. In the future machining and parts manufacturing, it can improve the processing efficiency and promote the optimization of titanium alloy material properties.

Materials for parts which are subjected to abrasive wear in service are typically selected on the basis of the microstructure type and hardness. Additional characteristics, such as grain size and the size and morphology of carbides are considered less frequently, although they may prove very important. This article deals with treatment cycles which combine an unconventional forming technique and subsequent heat treatment and explores its impact on abrasive wear resistance in X210Cr12 tool steel. Effects of microstructure refinement prior to and during forming and during heat treatment are described. The forming cycle involved semi-solid processing and was followed by quenching. This sequence refined the initial microstructure and altered the morphology of chromium carbides. The semi-finished products were then cryogenically treated at 160°C for 24 hours and in some cases, subsequently tempered at 300°C for 2 hours. Their wear resistance was tested by blasting and the relationship between the treatment and the weight loss in the test was assessed.

Nitriding is a technology that leads to an increase in the utility value of the product. It’s most im-portant benefits include increased corrosion resistance, abrasion resistance, wear resistance, increased resistance to fatigue failure under cyclic loading, and many others. The design of a suitable nitriding technology not only on the basis of empirics requires a closer study of the relationship between the structure of the nitriding layer, its properties and the course of a particular degradation process. Be-cause the life of most components is related to abrasion on the surface, the occurrence of fatigue cracks and corrosion effects, it is crucial to influence the mechanical and other properties in this sur-face area. High functional requirements are placed on the functional surfaces of steels for weapons production, which lead to a long service life, reliability and dependability of the components of the weapon system and its safe use. The paper discuss the influence of selected nitriding technologies on the mechanical properties of steel 42CrMo4 and 34CrNiMo6, especially on the hard and microhard-ness of surface layers, change of its structure and next to change the surface texture and dimension of component. The steels were nitrided in plasma and gas. Nitriding in gas led to more significant struc-tural changes in the surface layer of both steels compared to plasma nitriding.

In This study vanadium carbide coatings obtained by thermo-reactive deposition/diffusion (TRD) technique on cold work tool steel AISI D3. The TRD treatment were carried out in a molten mixture consisting of NaCl, CaCl2, ferrovanadium and aluminum, by heating this mixture at 1000 °C for 4h using a resistance-heating furnace under air atmosphere. The coating process was investigated using light microscopy LM, scanning electron microscopy/energy dispersive spectroscopy SEM/EDS, and X-ray diffraction XRD characterization techniques. The results indicated that the vanadizing process produced a homogeneous coating layer about 13 µm depth and its microhardness is 2300 HV. Carbide compounds that are formed are vanadium carbides phases (V8C7, VC, V4C3, V6C5, V2C), while EDS-Line scan results show chromium carbides phases formed in sublayer. The corrosion resistance of the vanadium carbide coatings was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a solution of 3.5 % NaCl. Vanadium carbide coatings improved the corrosion resistance of the substrates, vanadium carbide coatings showed the longest service life compared with the uncoated tool steel AISI D3.