Steel Shot Research Articles

EFFECTS OF HEAT TREATMENT ON THE IMPROVED WEAR RESISTANCE OF SHOT BLAST MACHINE BLADE MATERIAL

The blade is a component of the shot blast machine that functions as a thrower of small steel balls (steel shot). During its use, the blade undergoes impacts and friction with the steel shot, causing wear and a shortened lifespan. The material typically used for blades is white cast iron. Hence, the blade must possess good hardness and wear resistance. This study analyzed the causes of blade failure and proposed solutions in the form of hardening and tempering treatments. The tests conducted in this research included composition analysis, metallographic examination, hardness testing, and wear resistance testing. Based on the composition and hardness tests, the failure was attributed to material composition and hardness not meeting the ASTM A532 standards. The solution to this failure involves heat treatment to achieve hardness that complies with ASTM A532 standards, specifically hardening at 900°C for 40 minutes, followed by cooling with oil as the quenching medium. Then, the tempering process was carried out at 200°C, 250°C, and 300°C with holding times of 80 and 120 minutes. Post-heat treatment, the optimal hardness value, and the lowest wear rate were obtained at a tempering temperature of 300°C with a holding time of 120 minutes. The hardness value of the blade material under these conditions reached 63.8 HRC, and the wear rate was 1,21E-04 mm3.kg-1.m-1. A low wear rate indicates that the material has high wear resistance.

WITHDRAWN: Spatial and temporal variation in the prevalence of illegal lead shot in reared and wild mallards harvested in England

The use of lead shotgun ammunition for shooting wildfowl has been restricted in England since 1999, but surveys finding lead shot in harvested birds show compliance with regulations has been low. Following the announcement in 2020 of a voluntary transition from lead to non-lead shot by UK shooting organizations, we investigated spatiotemporal variation in the composition of ammunition used for shooting mallards Anas platyrhynchos. We collected 176 harvested mallards during the 2021/22 shooting season and analyzed recent shot extracted from carcasses to determine shot composition. Using a separate collection of ducks of known provenance, we used stable isotope analysis as a means of differentiating captive-reared from wild mallards. This allowed us to understand how compliance might vary between driven game shooters, characterized by shooting birds that are flushed over a stationary line of shooters, and who primarily harvest captive-reared and released ducks, and wild duck shooters. Of 133 mallards containing recent shot, 92 (69%) had been illegally shot with lead. Analysis of this and five comparable surveys between 2001 and 2019 indicates regional and temporal variation in lead shot presence in England. In the North West and West Midlands, the likelihood of mallards containing lead shot decreased significantly over time, but no other regions showed significant changes. The use of non-lead shot types varied over time, with increases in steel shot use approximately matched by declines in bismuth shot. Mallards likely to be reared were more likely to have been shot with lead (75%) than those likely to be wild (48%). This suggests the use of lead shot is more frequent among driven game shooters than wild duck shooters. In England in 2021/22, most mallards continued to be shot with lead, suggesting that neither legislation nor voluntary approaches have been effective in substantially reducing illegal use of lead shot.

Depth-resolved mechanical behaviour of shot peened 7050-T7451 aluminium surfaces using in-situ synchrotron X-ray diffraction

We have assessed the elasto-plastic (sub)surface behaviour of 7050-T7451 aluminium alloy treated by shot peening using S110 steel shots of 300 μm in diameter and two different intensities, namely Almen intensity (A) of 3.4 (low-intensity) and 10.9 (high-intensity). Shot peening (SP) is a cold work process applied in the aerospace industry to enhance the fatigue tolerance of structural components after machining. The local mechanical response within the SP-induced layer was depth profiled at room temperature by performing an X-ray micro-diffraction experiment in transmission geometry at a synchrotron source, during tensile loading of the specimen to rupture. The presence of a SP-induced layer in the specimen is evidenced by compressive longitudinal lattice strains (∼-540 με for low-intensity and ∼-4200 με for high-intensity at 0.1 mm from the surface for the 311 reflection), parallel with respect to the applied load, i.e. perpendicular to the direction of impact of the steel shots, and also by higher values of the Full-Width-at-Half-Maximum (FWHM) of the diffraction peaks than those measured in the bulk material, due to the local plastic deformation induced by shot peening. High-intensity shot peening produced a higher surface roughness (Sa ∼13 μm), and also two times thicker deformed surface layer (∼0.4 mm), than low-intensity shot peening (Sa ∼2 μm and ∼0.2 mm thick deformed layer). For both shot peening conditions, the local yield stress of the surface layer and bulk material were similar, however the severely affected layers exhibit a non-linear elastic behaviour when applying loads lower than the yield stress of the material. Beyond yielding, the presence of SP-induced layers is mainly evidenced by the relatively higher value of the FWHM near-surface compared to the bulk (∼20 % higher for low-intensity and ∼40 % for high-intensity), due to the initial plastic deformation accumulated during shot peening and additional plasticity during loading of the specimen.

Fluid-particle-structure interaction in single shot peening

Shot peening is a widely used cold-working process. Physical phenomena of shot peening are analyzed using the developed fluid-particle-structure coupled solver. The influences of the flow field and shot peening parameters such as the shot impact velocity and shot size are investigated in the case of the falling, impacting, and rebounding single particle. The weakly coupled solver applies the immersed boundary method which enables direct evaluation of the interactions between the unsteady flow field and moving/deforming objects. The elastoplastic object of AISI4340 during the collision of rigid steel shot is analyzed dynamically using the finite element method. Consequently, it is clarified that the flow field of the post-collision between the shot and structure can be characterized by the relative Reynolds number, which is based on the shot diameter and relative velocity between the uniform flow and rebounding shot velocities. As the relative Reynolds number increases, the complex flow field and vortex structures are generated at the collision location. These fluid structures affect the collision phenomena resulting in the random behavior of the shot and the asymmetric indentation in the structure.

Exploring microstructural evolution, nitrogen depth profile, and dry wear performance in 31CrMoV9 steel through combined severe shot peening and plasma nitriding

The present study investigates the influence of severe shot peening (SSP) on the plasma nitriding behavior and sliding wear performance of 31CrMoV9 steel. Initially, the steel was austenitized at 880 °C, followed by oil quenching, and tempering at 520 °C for one hour. These samples were shot peened using high-carbon steel shots, resulting in an enhancement in surface hardness up to 447 HV, gradually converging to the initial martensitic hardness after 140 µm depth. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) scrutinized the initial and surface treated martensitic samples. Afterward, the plasma nitriding treatments were carried out at temperatures of 400 °C, 450 °C, and 500 °C for 8 hours in a 30% N2 + 70% H2 atmosphere and 300 Pa pressure. Microhardness testing, SEM, XRD, and glow-discharge optical emission spectroscopy (GDOES) evaluated both plasma nitrided (PN) and severe shot peened/plasma nitrided (SSP-PN) samples. Cross-sectional SEM observations revealed compound layer thicknesses of approximately 2.8 µm, 5.0 µm, and 6.3 µm for PN samples at 400 °C, 450 °C, and 500 °C, respectively. SSP-PN samples exhibited a substantial increase — roughly 71%, 44%, and 33% increase, respectively, compared to PN samples. GDOES analysis supported this trend and indicated enhanced nitrogen diffusion depth, particularly evident in SSP-PN samples at consistent temperatures. The XRD results showed the stability of Fe4N, Fe2–3N, and CrN phases at all three nitriding temperatures. Furthermore, the intensity of these phases increases with temperature and is augmented by the application of the SSP. Microhardness measurements indicated hardness escalation: from 775 HV to 980 HV at 400 °C, 932 HV to 1096 HV at 450 °C, and 1011 HV to 1205 HV at 500 °C due to SSP. Finally, the wear performance was investigated between the non-nitrided, SSP, PN, SSP-PN, samples. Initially, SSP led to decreased wear performance up to 500 m, followed by improved behavior up to 1500 m. At 400 °C, the SSP-PN sample exhibited a 12% lower wear rate than PN. At 450 °C and 1500 m, the SSP-PN sample displayed a 24% reduction, while at 500 °C, it showed a 27% reduction compared to PN. SEM observations indicated abrasion as the primary wear mechanism across all samples. The overall results indicated a significant similarity in the nitrogen depth profile, hardness depth, and wear performance between the SSP-PN sample at 450 °C and the PN sample at 500 °C. The fact suggested a potential reduction of approximately 50 °C in the typical plasma nitriding temperature for 31CrMoV9 steel as a result of the SSP process.

Effect of surface contamination on electrochemical corrosion behavior of ultrasonic shot peened TA2 alloy

Ultrasonic shot peening (USSP) is a technique to tune the performance of metallic materials by generating gradient nanocrystalline structure (GNS) as well as residual compressive stress. However, surface contamination can also be introduced during USSP. The nature of this surface contamination layer and how it influences the corrosion behavior of alloy require further investigation. In this work, we found that a Fe-rich oxide layer with a thickness of around 50 nm, mainly in an amorphous state, was introduced on the topmost surface layer of TA2 alloy during USSP treatment. Electrochemical corrosion results indicate that this Fe-rich oxide significantly decreases the corrosion resistance of TA2 alloy. By polishing off this surface contamination layer, the corrosion resistance of the peened sample becomes superior compared to the untreated counterpart, indicating that the introduction of the Fe-rich oxide layer conceals the beneficial effect of GNS caused by USSP. Additionally, the corrosion resistance of TA2 alloy after USSP treatment exhibits a downward trend with the increasing repeated use of steel shots. The corrosion mechanism and potential use of this surface contamination layer are also briefly discussed.

Study on the construction and filtration characteristics of a Triple-Layer granular bed filter

Granular bed filtration is a high-temperature dust removal technology with unique advantages. In this paper, through the fluidization tests, the densities and granule sizes of the triple-layer filter granules were optimally matched, and a triple-layer granular bed filter was constructed, which could be fluidized in layers and meet the requirement for removing ash deposited in the layers by fluidization without destroying the triple-layer structure. The whole-bed filtration tests at room and high temperatures showed that the triple-layer granular bed filter which consisted of cenosphere layer, desert yellow sand layer and 304 stainless steel shot layer had lower total pressure drop and outlet dust concentration, and higher filtration efficiency than the dual-layer granular bed filter which consisted of cenosphere layer and baozhu sand layer. The separated-bed filtration tests at high temperature found that the upper filter layer experienced the deep-bed, transition and surface filtration periods. The middle and lower filter layers didn’t experience the surface filtration period and the grade filtration efficiency curves were “V” shapes, with the lowest efficiency for particles around 1.3 μm.

Effects of Shot Peening on Mechanical Properties and Microstructural Evolution of AMS 6265 Steel Surface Treated for Critical Aircraft Components

Considering its very good mechanical properties, especially the high strength and toughness, and also its well-known case-hardening ability, the AMS 6265 (9310 VAR) low alloy steel is widely used in the aeronautical industry for manufacturing heavy-duty products and parts, like pinions, shafts, gears, piston pins, and other critical aircraft components. In this study, a surface modification treatment via shot peening method was applied to an initially case-hardened (quenched and carburized) AMS 6265 aircraft steel. In shot peening, the mechanical properties of the surface layer are improved, by generating plastically deformed micro-areas when exposing the metal surface to a stream of steel, glass, or ceramic shots. The initial case-hardened AMS 6265 alloy steel and all surface treated samples were structurally investigated by means of OM (optical microscopy), SEM-BSE (scanning electron microscopy – backscattered electrons imaging), and XRD (X-Ray diffraction) analysis, being also mechanically tested in tensile and microhardness tests. The influence of different shot peening parameters (shot size, peening pressure, and exposure time) on mechanical properties evolution and microstructural features, for the analyzed AMS 6265 alloy steel, was established in this present research.

The relationship between pellet size and shotgun dispersion patterns.

When reconstructing a shooting incident with a shotgun, the muzzle-to-target distance can be determined by relating the size of a dispersion pattern found on a crime scene to that of test shots. Ideally, the test shots are performed with the weapon and ammunition that were used in the incident. But sometimes examiners will have to resort to alternatives, such as using cartridges of the same brand and type but with another pellet size. For this reason, the relationship between pellet size and shotgun dispersion patterns was studied with both lead and steel shotgun pellets. Cartridges were loaded with identical cartridge cases, powder charges, and wads but with different pellet sizes, below size B. The cartridges were fired, and the dispersion patterns at 5 m in front of the muzzle were measured and compared. The results provide strong support for the proposition that shotgun dispersion patterns with both lead and steel shot increase with decreasing pellet size if all other relevant parameters are kept equal. The results also provide an indicative measure of the magnitude of the effect. Pattern sizes were approximately 1.7 times larger with #9 than with #0 lead shot and 1.4 times larger with #9 than with #1 steel shot. The differences between consecutive shot sizes were generally smaller. This means that cartridges of equal brand and type but with the next nearest shot number can be used for a muzzle-to-target distance determination, keeping the information of the current study in mind in the final interpretation of the results.

Influence of surface treatment on metal dusting resistance of welds

AbstractWelds of the commercial Ni‐based alloys 602 CA, 699 XA, 601 and 690 were exposed under harsh metal dusting conditions. The pit formation was compared for as‐welded, brushed, ground, glass bead blasted, steel shot peened and dry cathodic pickled surfaces. Surface treatments were applied by industrial partners. When (stainless) steels were involved in the surface treatment, Fe contaminations acted as catalyst sites for pit initiation. A fast metal dusting attack was also observed on dry cathodic pickled samples. A beneficial effect was attributed to deformation of the sub‐surface zone, as it provides diffusion paths for oxide formers (by grinding and glass bead blasting). In the same region, formation of α‐Cr (BCC) precipitates was observed. The best performance was found for samples where the weld bead was fully flattened by grinding to P40 grit. In addition, it was demonstrated that on‐site slurry aluminization further enhances the resistance against metal dusting attack.

Design and fabrication of light weight low-cost polio braces using shot peened AA2024 for alternatively abled

The use of braces and splints to stabilise weak or paralysed body parts is known as orthotics in medicine. The aim of this research is to develop a low cost, less weight, high strength polio brace (used for KAFO) without compromising the comfort to the wearer. In order to fabricate the brace with the above declared functionalities, shot peened AA2024 is employed as it has high strength to weight ratio and the cost is also low. Cut wire steel shots are used as shot material and the shot peening (SP) parameters, viz, shot pressure and shot distance are optimized and the same is used for peening the braces made of AA2024.

Static, fatigue and hygroscopic performance of steel-reinforced resins under various temperatures

Resins are essential structural materials predominantly used in load-bearing connections such as adhesively bonded joints and resin-injected bolted connections. In an effort to improve the latter, a new injection material, Steel Reinforced Resin (SRR), has been developed, consisting of spherical steel particles embedded in a resin. SRR's applicability has been explored in injection bolts used in composite steel-to-concrete floor systems and as an injection material in Fibre Reinforced Polymer (FRP) sandwich web-core panels of highway bridges. While the short-term and creep performance of SRR has been researched, its fatigue behaviour remains unexplored. From joint-level cyclic experiments with SRR, it was observed that joint endurance is dominated by SRR's fatigue performance. There is currently no research on the influence of temperature on SRR's mechanical properties and moisture uptake. This paper fills this gap, by investigating the static and fatigue performance of epoxy, unsaturated polyester polyurethane hybrid (UPE + PU), and vinyl ester based SRRs under ambient and elevated temperatures. Water absorption assessments were conducted on the three resins with and without steel particles to evaluate their durability and corrosion resistance. The results show that temperature significantly impacts tensile stiffness, tensile splitting strength, and fatigue life. Epoxy based SRR endured 20 times more tensile splitting stress cycles to failure compared to the UPE + PU resin based SRR at the same stress range. However, after 200 days of water exposure at maximum temperature, the epoxy resin (with and without steel shot) exhibited a weight increase of 4.0% and 0.50% respectively, suggesting that despite its superior fatigue performance, it may not be suitable for SRR applications in high moisture environments. In contrast, UPE + PU resin and its corresponding SRR displayed substantially lower water absorption.

Revealing the relationship between the shot type and fatigue performance of laser powder bed fused 304L steel following shot peening

Shot peening (SP) is gaining popularity as a post-processing method for improving fatigue properties of laser powder bed fused (LPBF) metallic materials. This work investigated the influence of shot type on the surface strengthening and life improvement of LPBF 304L stainless steel (SS) with a rough as-built surface using ASH 110 steel shot, AZB 300 ceramic shot, and CW 35 strengthened steel shot. The shot characteristics (size, shape factor, and hardness), SP surface characteristics (morphology, roughness, residual stress, and hardness), and SP subsurface characteristics (grain refinement, deformation twinning, martensitic transformation, and defect distribution) were fully characterized and quantified. Particularly, the foldings with rolled-up edges that affected surface finish appeared on the SP surface, and their formation was ascribed to the as-built surface morphology containing incompletely melted powder particles and agglomerations, as well as the shot properties such as size, hardness, and sharpness. The irregular LoF defects between the contour region and infill region could not be entirely eliminated/healed utilizing SP procedures, and these defects were always the fatigue crack initiation sites for AB and SP samples. Therefore, the critical role of “penetration depth” of the kinetic energy on irregular LoF defects and fatigue performance was highlighted. A larger penetration depth can be achieved by employing small-sized ceramic shots with high hardness, deformation resistance, and kinetic energy, inducing refined structures and compressive residual stress around the irregular LoF defects, thereby constricting the fatigue crack initiation and propagation. This work provides a valuable reference for SP process design and optimization of LPBF metallic materials.

Support for nonlead shot for dove hunting in Illinois

AbstractMourning doves are the most hunted game species in the United States. Mourning dove populations are declining, and the continued use of lead shot has been cited as one contributory factor. We examined the relationship between support for a ban on lead shot when dove hunting and 3 sets of variables: (1) beliefs about lead and steel shot, (2) prior dove hunting experiences, and (3) hunter demographics. Data were obtained from a mailed survey of 4,330 dove hunters in Illinois (response rate = 59%). Our results indicated that 81% of respondents were opposed to restrictions on the use of lead shot and these individuals believed that lead ammunition did not pose a risk to wildlife and that steel shot was less effective than lead shot. Supporters of banning lead shot were almost twice as likely to use steel shot, reported 2 fewer years hunting doves, went dove hunting 75% as much, and harvested 2/3 as many doves as those who opposed a ban. Consistent with social‐psychological theory, beliefs were the best predictors of whether an individual supported or opposed a ban, followed by dove hunting experiences and demographic variables.

Hardening of long steel products by shot peening

The negative effect of surface defects and a decarburized layer on the cyclic resistance of steel products is shown. Information about the places of destruction of parts in operation and during bench tests are presented. The use of shot peening of long-length steel products of complex configuration in relation to the hardening of the surface layer of parts by methods of thermochemical treatment and high-frequency hardening is justified. The technology of work hardening of the surface layer of the truck front axle beam has been developed. After straightening long-length parts to eliminate warpage and achieve geometric accuracy, shot peening is performed. It is recommended to use DSLU – 2.2. steel shot for hardening. Information on the structure, grain composition and hardness of various types of shot are presented. Processing parts with shot is carried out for 20 minutes. An increase in the microhardness of the surface layer by 77HV in relation to the hardness of the base metal of the part was established. As a result of hardening of the surface layer, the cyclic resistance of the front axle beam exceeded 1 million 400 thousand cycles. A device for assessing the degree of hardening by shot of the truck front axle beam has been developed and implemented. The basis of the device is a beam on which Almen plates are installed in the recesses. The plates are located in different parts of the part and take into account the features of its configuration and the most loaded areas in operation.

Analysis of gas–solid two-phase flow and structure optimization of mobile shot blasting machine recovery device

To address the problem of low efficiency of recycling process waste by gas–solid two-phase flow of the shot blasting machine recycling device, a method and structure by increasing the negative pressure value and optimizing the outlet pipe position are proposed. Computational fluid dynamics (CFD), discrete element method (DEM) and discrete phase model (DPM) were used to study the waste recovery efficiency at different pressure outlet conditions and outlet pipe locations. The validity of the model was verified by velocity tests at the outlet and inlet compared with simulations. The effect of particle size and particle generation rate on solid particle recovery efficiency was further investigated by analyzing the flow field distribution of the recovery unit. The results show that the maximum velocity of the gas phase in the recovery device increases with the increase of the absolute value of the outlet pressure, when the outlet pressure is -6500 Pa, the maximum velocity is 67.59 m/s. When the absolute value of the outlet pressure is greater than 6000 Pa, a small amount of steel shot particles is discharged from the recovery bin under the action of the outlet pressure, resulting in the loss of steel shot particles. After the outlet pipe position optimization, the steel shot particle recovery efficiency increased by 10% and the waste particle recovery efficiency increased by 18.9%.

Assessment of Corrosion Resistance and Hardness of Shot Peened X5CrNi18-10 Steel.

Although the application of shot peening facilitates increasing hardness and corrosion resistance of stainless steel, the inappropriate peening parameters result in overestimated hardening and exaggerated surface roughness, which deteriorate the surface morphology and negatively affect the corrosive behavior of treated steel. Therefore it is crucial to select the peening parameters that allow obtaining both high hardness and elevated corrosion resistance. This study aims to determine the effect of X5CrNi18-10 stainless steel samples shot peening on the surface morphology, hardness, and corrosion resistance. Samples were shot peened with a CrNi steel shot, applying 0.3 MPa and 0.4 MPa peening pressures and treatment times of 60 s and 120 s. Roughness analysis and microscopic and SEM-EDS examination were employed to state the effect of peening parameters on the sample's corrosive behavior in a 3.5% NaCl solution. The most promising shot peening parameters for Vickers hardness and electrochemical corrosion resistance were selected. It is revealed that the surface roughness increase has a detrimental effect on the corrosion behavior. Overall, high corrosion resistance and the high hardness of stainless steel samples were noted for the peening pressure of 0.4 MPa and time treatment of 60 s.

Simulation of dynamic contact during shot blasting of parts

Shot blasting consists in hardening of the parts surface layer or workpieces with a stream of solid particles, mainly in the form of hardened steel balls. The purpose of the work is to develop and test a method for calculating the parameters of an elastic-plastic dynamic contact during shot blasting of parts based on mathematical modeling. The research technique is based on the consideration of a three-stage model of workpiece deformation under elastic-plastic impact by a steel spherical indenter. At the initial stage, the deformation is carried out elastically. Then, under some dynamic load, in the near-surface layer of the impacted body, a region of plastic state is generated, surrounded by an elastically deformable material. With a further increase in the dynamic load above a certain characteristic value, the region of the plastic state comes to the surface of the impacted part. Subsequently, the process is characterized by elastic-plastic indentation of the indenter (shot) into the impacted part. A method for upper calculating estimate the parameters of the dynamic contact of steel shot with parts based on the energy theory of elastic-plastic impact has been developed. To separate the elastic and plastic components of the deformation energy, the velocity recovery factor upon impact was used. The deformable material is accepted at the final stage of deformation as an ideal elastic – plastic material obeying the Prandtl’s scheme. Analytical dependencies convenient for practical use are obtained, which allow one to make calculating estimate of the depth and diameter of the imprint. Estimated calculations of the depth of the indentation depending on the speed of exposure to steel shot for shot blasting of a number of structural carbon steels have been performed. The results of the research can be used in the educational process in the preparation of engineering personnel of the machine-building profile, as well as in engineering practice.

Numerical Modelling and Simulation of Heat Transfer during Magnetic Moulding of Al/SiCp Metal Matrix Composites

In traditional casting, sand is used as a mould material to carry heat away from the melt. However, sand has certain disadvantages, such as poor thermal conductivity, burning of binders, undesirable transition resulting in mould failure, and defects in the components. To overcome these limitations, magnetic moulding technology was introduced more than a few decades ago, but the process never achieved the required industrial developments to commercialise this technology. It is essential to reconsider and develop this technology further to use it as a regular production process. In this paper, processing of Al/SiCp composite using magnetic moulding technology is discussed. The heat transfer results of magnetic moulding process are simulated using COMSOL Multiphysics software and compared with the sand casting process. The temperature distribution, thermal conductivity, and phase change have been studied, finding that steel shots as mould materials show better heat transfer results when compared with sand. This better heat transfer led to a decrease in solidification time by 25%, which in turn improved the hardness (by 70%), impact toughness (by 4 times), and wear resistance (by 42%) of the Al/SiCp cast produced. These results very clearly illustrate the unique signature of the magnetic moulding process.

Preparation of the Surface of Long-Dimensional Rods of Hydro-Cylinders for Thermal Spraying Using an Abrasive Jet

Preliminary cleaning of the surface of hydraulic cylinder rods is of great importance for subsequent coating. The most widely used surface preparation for thermal spraying is jet-abrasive treatment. The shot blast modes provide the hardness and strength of the material being processed. The impact of the abrasive makes the surface rough, increasing the contact area. Experimental studies of jet-abrasive processing of the hydraulic cylinder rod surface, as well as its activation for the thermal spraying, were carried out. The prepared surface of the rod for thermal spraying must meet the requirements for surface roughness and the size of the hardened layer at work. The experiments made it possible to identify the optimal modes of jet-abrasive treatment, which affect surface roughness and abrasive penetration of abrasive. To obtain the desired roughness values, it is preferable to use the following: a steel shot with an abrasive particle size in the range of 0.3–1.5 mm, taking the compressed air pressure in the range of 0.4–0.7 MPa; processing time—within 3.5–5 min; counterflow angle with the surface—70–90°; consumption of abrasive particles—300–500 kg/h. A special installation for jet-abrasive processing has been designed, which makes it possible to restore the surfaces of long rods by thermal spraying directly at the site of operation of the large machines.