High-chromium cast irons are used in the mining, metallurgical, and petrochemical industries. High-chromium cast irons are used for repairing and protecting industrial equipment, increasing its wear resistance and corrosion resistance. A brief review of domestic and foreign research in the field of high-chromium cast iron is performed. It highlights the main industries that use high-chromium cast irons and their applications, as well as the requirements and production methods. The article analyzes manual arc welding, semi-automatic welding, submerged arc welding, gas welding, laser welding, induction welding, and plasma surfacing. The influence of heat treatment, alloying, and high-energy effects on the formation of functional properties has been studied, and the structure and properties of high-chromium cast iron with different chromium contents have been compared. The article notes that different methods are used depending on the requirements for the parts.In the commonly used high-chromium cast iron surfacing, primary chromium carbides Cr7C3, Cr3C2, and a metal matrix are present. The carbides have a plate-like, needle-like, or mesh-like structure. They provide resistance to abrasive wear, reduce impact toughness, and improve ductility. The metal matrix can have various structures, including ledeburite, austenite, martensite, and ferrite. It is noted that in most cases, the ideal structure of the welded coatings should consist of evenly distributed chromium carbides in a viscous martensitic-austenitic matrix. The prospects for creating high-chromium cast iron welds using electron beam surface treatment are outlined.

This paper presents effects of addition of 4wt.% of Ti to Co-Cr-Mo alloy by µ-plasma arc metal powder additive manufacturing (µ-PAMPAM) process on microstructure, phase evolution, bending strength, tensile and compressive yield and ultimate strength, % elongation, microhardness, porosity, and density of the resultant alloy and their comparison with Co-Cr-Mo alloy. Microstructure and phase evolution study of Co-Cr-Mo alloy showed Co-rich matrix comprising of γ-Co and ε-Co phases, formation of Cr7C3 and Cr23C6 carbides due to presence of carbon and affinity of Cr towards it, and micro-cracks. Addition of 4 wt% Ti to Co-Cr-Mo alloy refined its grains, minimized formation of micro-cracks, led to formation of β-Ti phase and Co-Ti intermetallic compound along with the chromium carbides. It also reduced porosity and density of the resultant Co-Cr-Mo-4Ti alloy. Grain refinement increased flexural strength of Co-Cr-Mo-4Ti alloy. Solid solution effect of Ti increased tensile and compressive yield strength, ultimate compressive and tensile strength, and percentage elongation of Co-Cr-Mo-4Ti alloy as compared to Co-Cr-Mo alloy. Microhardness of Co-Cr-Mo-4Ti alloy increased to 473MPa from 382MPa of Co-Cr-Mo alloy due to formation of Co-Ti intermetallic compound and β-Ti phase. All these improvements enhance durability and strength of Co-Cr-Mo-4Ti alloy along with a reduction in stress shielding effect as compared to the Co-Cr-Mo, making it more suitable for knee prothesis applications.

This study investigates a hybrid processing route that integrates localized fusion-based additive manufacturing and hot forging for the production of complex-shaped components, with emphasis on metallurgical integrity and mechanical performance. The DIN 8555 E6-UM-60 alloy, traditionally classified as martensitic and applied under severe wear conditions, exhibited atypical metallurgical behavior during hybrid processing, notably the consistent formation of chromium carbides under specific thermomechanical conditions. Metallographic analyses, microhardness measurements, thermographic monitoring, hot tensile tests, and room-temperature tensile tests were performed to establish correlations between microstructure, thermal history, and mechanical response. Specimens produced by additive manufacturing and subsequently hot forged showed a significant reduction in porosity, improved microstructural homogeneity, and partial retention of hardening phases, enabling discussion of recrystallization mechanisms, phase stabilization, and precipitation phenomena in martensitic alloys processed by additive manufacturing. Hot tensile tests revealed limited hot workability of the alloy, while room-temperature tensile tests led to premature fracture, with failure consistently initiating at pre-existing microcracks formed during the forging stage. Although detrimental, these microcracks provide valuable insight into critical processing conditions and ductility limits of the material. Overall, the hybrid route demonstrates strong potential for industrial applications, highlighting the importance of precise thermomechanical cycle control to mitigate defects and enhance structural reliability.

This article is devoted to the investigation of the prospects for resource-saving development of laser surface alloying technology for machine-building blanks by replacing the expensive pure metal powders used for this purpose with their simple oxides, while ensuring complete slag-free reduction of the latter using a strongly and rapidly oxidizing gas such as methane. To justify the effectiveness of the proposed approach, a specific case study was conducted involving the laser surface alloying of AISI 1045 structural steel with chromium recovered from its trivalent oxide Cr2O3 of chemical purity. To this aim, a complete thermodynamic analysis of the interaction of Cr2O3 - CH4 components was performed in the temperature range of 400 - 2500 K, which is relevant for laser surface doping, with consideration of the decomposition of part of the methane that was directly exposed to the focused laser beam. It has been established that the chromium reduction process proceeds in two stages: solid phase (1150 - 1350 K) and liquid phase (1550 - 2000 K). In the first case, the process proceeds with the formation of chromium carbides Cr3C2 and Cr7C3, and in the second case, with the decomposition of the latter into elemental (condensed) chromium and free (amorphous) carbon, which contributes to the further complete carbothermal reduction of the residual locations of the initial oxide layer. It is recommended that the second stage of recovery be carried out under dynamic vacuum conditions, ensuring the removal of CO and H2 reaction gases. The generalization and implementation of the proposed technological solution can lead to significant savings in expensive alloying element powders, as well as reduce their irretrievable losses in the form of burn-off and blow-off caused by laser evaporation. It is noted that the proposed resource-saving approach to surface laser alloying technology may serve as a significant driver for further progress in this important scientific and technical field.

Inconel 625 alloy is widely recognized for its excellent performance in corrosive and abrasive environments, making it a preferred material in challenging applications. To further enhance its resistance to corrosion and wear, this study investigates the application of plasma-sprayed coatings using Chromium Carbide Cr 3 C 2 and Stellite. Both coated and uncoated Inconel 625 specimens were subjected to high-temperature sliding wear tests using a pin-on-disc tribometer. The wear behavior was evaluated by examining the worn surfaces through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy. Additionally, the hardness of all specimens was measured using a Vickers hardness tester. Results from microhardness tests revealed a significant increase in hardness due to the coatings. The Cr 3 C 2 -coated sample showed an increase in Vickers hardness (HV) by 42.6%, while the Stellite-coated sample exhibited a 32.7% rise in HV, compared to the uncoated Inconel 625 specimen, which recorded a hardness of 505 HV. SEM analysis confirmed a strong adhesive bond between the coating materials and the substrate, indicating good coating integrity. Furthermore, wear tests conducted at varying temperatures demonstrated different wear behaviors. Notably, the Stellite-coated samples performed better under high-temperature conditions, showing improved wear resistance compared to both the Cr 3 C 2 coated and uncoated samples. These findings suggest the potential of such coatings for enhancing the durability of Inconel 625 in extreme working environments.

Austenitic stainless steel 08Kh18N10T (AISI 321), stabilized with titanium, is used to manufacture nuclear power equipment and pipelines. One of the requirements for tubular products for nuclear reactors is a high yield strength, measured at 350°C, after final solution annealing in the temperature range of 1020–1080°C. This article reviews the scientific literature on ways to increase the yield strength of this steel. A literature review indicates that cold deformation of 08Kh18N10T steel accelerates the precipitation of dispersed titanium carbide particles, which inhibit static recrystallization during subsequent heating. Conversely, with increasing strain, the driving force for recrystallization increases. Therefore, to prevent static recrystallization during austenitization and ensure increased yield strength, the degree of preliminary deformation should be limited so that the increase in the driving force for recrystallization does not overwhelm the inhibiting effect of dispersed carbide precipitation. Plastic deformation of 08Kh18N10T steel in the temperature range of 800–900°C is accompanied by dynamic recovery and provides a more heat-stable dislocation structure capable of delaying recrystallization in the austenitizing temperature range. An increase in austenite grain size further suppresses static recrystallization and softening processes during annealing. However, in coarse-grained steel, deformation in the temperature range of 800–850°C may lead to the precipitation of chromium carbides, which reduce resistance to intergranular corrosion.Stabilizationheat treatment, designed to increase the steel's resistance to intergranular corrosion, can simultaneously enhance the strength properties of 08Kh18N10T steel due to precipitation strengthening caused by titanium carbide particles. The effective method for increasing the strength properties of this steel is a combination of preliminary warm deformation followed bystabilizationheat treatment. This ensures the simultaneous action of two strengthening mechanisms (work hardening and precipitation hardening), which, according to literature data, lead to a significant increase in the yield strength measured at a temperature of 350°C. It is noted that 08Kh18N10T steel, microalloyed with boron at a concentration of ~0.003 wt.%, is being considered as a promising material for nuclear power. Microadditions of boron not only increase yield strength but also reduce the steel's susceptibility to intergranular corrosion

The study aimed to evaluate the quality and structure of test clads made by means of laser deposition of chromium carbide - nickel aluminide powder with the nominal chemistry Cr3C2 7(Ni 20Cr). The clads were deposited on the substrate of unalloyed mild steel S235, using different laser power parameters and assisted by two different shielding gases, inert argon and active nitrogen. As part of the research, images of the macrostructure, microstructure, and analysis of the chemical composition using SEM and EDS analysis were conducted. The next stage was to carry out hardness tests, starting from the face of the clads and ending with the base metal. The 5 Whys method, as a quality tool, was additionally applied for determining causes of imperfections and defects. The influence of laser cladding parameters and the shielding atmosphere on the quality and properties of clads was determined.

In the welding process it will produce excessive heat and in the slow cooling process it will form chromium carbide which precipitates on the grain. These deposits can cause a decrease in the physical and mechanical properties of a material. This research aims to determine the effect of tensile strength and hardness of material resulting from GTAW welding on ST 45 Steel on variations in cooling media. The research method used is quantitative experimental, where the specimens are welded and cooled with three cooling media, then tested for tensile and Vickers hardness to evaluate their mechanical properties. The results showed that the SAE 20 W-50 oil cooling media produced the highest Modulus Young value (average 1584.60 MPa) and the highest Vickers hardness (459.33 HVN), while air provided a higher Yield Strenght (368.72 MPa). Statistical analysis using ANOVA confirmed that the differences were statistically significant. The conclusion of this research shows that SAE 20 W-50 oil is most effective in increasing material hardness and stiffness, while air is superior in increasing tensile strength.

It is well established in the literature that the precipitation of different carbide types and intermetallic phases in stainless steels can lead to drastic consequences in their mechanical and corrosion behavior. Chromium carbide particles precipitate at grain boundaries, creating chromium depletion zones that expose the stainless steel to high corrosion penetration in harmful working atmospheres. The aim of this work is to evaluate the effect of electrolytically charged hydrogen on the mechanical behavior of heat treated AISI 316L austenitic stainless steel samples. To achieve a homogeneous distribution of carbides, specific heat treatments were conducted before tensile tests. Subsequently, a group of heat-treated samples were hydrogen-charged. After tensile tests carried out at high (0.003 s−1) and low (0.000003 s−1) strain rates, the resulting fracture surfaces exhibited mixed behavior in hydrogen-charged samples, i.e., ductile-brittle, in comparison with the ductile morphology obtained in uncharged ones. Additionally, in hydrogenated samples, cracks were associated with fine chromium carbides. Coincidentally, there was a ductility loss in hydrogen-charged samples, which was not observed in uncharged ones. In order to identify hydrogen-carbide interactions, combined studies of Differential Scanning Calorimetry (DSC) and a selective metallographic technique made it possible to identify grain boundaries and carbides/matrix interfaces as the main hydrogen traps. Finally, regarding strain rate effects on mechanical properties, it could be stated that when the strain rate decreases, the embrittlement effect of hydrogen is more explicitly manifested in conjunction with a microstructure sensitized by heat treatments and revealed by the mixed mode of fracture in hydrogen-charged samples.

The process of obtaining chromium carbide powder using chromium powder as a precursor and hexane vapor as a carbon source was studied. Powders of three stable chromium carbides were obtained in the temperature range of 700–800 °C: Cr3C2, Cr7C3 and Cr23C6. The average crystallite sizes of chromium carbides are in the range of 28–42 nm. The adsorption curves of the powders of the obtained carbides correspond to type IV according to IUPAC. They are distinguished by the presence of a hysteresis loop and are typical of materials with a mesoporous structure.

Plastic waste is a serious environmental problem in Indonesia due to its non-biodegradable nature. One of the management efforts is carried out at TPSA Bagendung through the use of a plastic shredding machine. However, the shredder blades often experience wear and chipping, which reduces machine performance. This study aims to redesign the blade material and geometry to improve wear resistance and hardness. The initial material was medium carbon steel with an average hardness of 44.46 HRC and a composition of 0.410% C; 0.376% Cr; 1.14% Mn; and 0.223% Si. The replacement material was selected from D2 steel with higher carbon and chromium content, followed by heat treatment, resulting in an average hardness of 60.61 HRC with a composition of 1.62% C; 12.1% Cr; 0.270% Ni; 0.778% Mo; and 0.742% V. Metallographic analysis using an optical microscope at 1500× magnification after Nital etching revealed a dominant needle-shaped martensitic structure with chromium carbide precipitates uniformly distributed along grain boundaries. This microstructure strengthens the matrix, enhances wear resistance, and directly correlates with the increased hardness. In addition, the modification of the bolt slot length from 40 mm to 45 mm provided greater adjustability of the blade position, thereby extending its service life. Overall, the combination of material engineering and design modification resulted in shredder blades with improved mechanical properties, higher wear resistance, and longer durability compared to the original material.

Alkaline functional chromium carbide: Immobilization of ultrafine ruthenium copper nanoparticles for efficient hydrogen evolution from ammonia borane hydrolysis.

Ni-substituted WC cemented carbides with chromium carbide coatings: Enhanced high-temperature oxidation resistance

This article presents structural analysis and mechanical property evaluation of two coatings applied using the APS (Air Plasma Spraying) method on a P250GH boiler steel substrate. Two different powders were used for coating deposition: WCCoCr, based on tungsten carbide, and CrCNi, based on chromium carbide. To assess the coating-substrate bond quality, a scratch test was conducted using a Rockwell diamond indenter under a constant load of 10 N, moving from the substrate toward the coating. No delamination at the coating-substrate interface was observed, indicating a high-quality bond. Microhardness measurements were performed using a 200 g load. The average microhardness values were 886 HV0.2 for the WCCoCr coating and 904 HV0.2 for the CrCNi coating. The coatings were also tested for cavitation resistance according to the ASTM G32-16 standard. Surface roughness profiles were measured before and after 120 minutes of cavitation exposure. Cavitation wear was evaluated based on the difference in roughness values, determined by the Sz parameter, which, according to ISO 25178, is defined as the difference between the highest peak and the lowest valley on the surface. The obtained results indicate that APS thermal spray coatings based on tungsten carbide powders can be used for machine components to enhance cavitation erosion resistance.

Abstract This study compares the wear resistance of three experimental high-chromium white cast iron (HCWCI) alloys with varying chromium content (20.2–24.5 wt%) and carbide morphologies for mining applications. HCWCIs are valued for their high hardness and toughness, making them suitable for abrasive and impact wear conditions. Wear performance was evaluated using slurry rubber wheel abrasion, pin-on-disc sliding, and solid particle erosion tests. Results showed that wear resistance depended heavily on the morphology of Cr-rich primary carbides. The alloy with 22.2 wt% Cr exhibited strong resistance in slurry abrasion and sliding wear but performed poorly in erosion tests, attributed to its carbide size and shape. This work underscores the importance of carbide morphology in tailoring HCWCI alloys for specific wear environments, highlighting their potential as durable protective liners in mining ope0ns.

The influence of TIGW parameters on the microstructure and mechanical behaviour of SS304 stainless weldments

Wire arc additively manufactured super duplex stainless steel: microstructural and property evolution under thermal aging and solution treatment

Gallium-based liquid metal is corrosive to steel alloys, forming FeGa3 surface films which can potentially be applied as a solid lubricant to enhance wear resistance and mitigate liquid metal-induced corrosion. However, the characteristics of these films remain insufficiently explored. In this study, Ga-In-Sn alloy was ultrasonically soldered onto annealed and decarburised substrates, followed by heating in a vacuum chamber to form a 30 μm thick FeGa3 reaction layer. The film on the annealed samples with an alpha-ferrite microstructure exhibited high porosity and a surface roughness of 1.97 Ra. In contrast, the film on the decarburised samples with a ferritic microstructure showed minimal porosity and a lower surface roughness of 1.29 Ra. Nanoindentation tests revealed Young modulus values of 231 GPa and 242 GPa and hardness values of 11.4 GPa and 12.7 GPa for the annealed and decarburised samples, respectively. The high porosity in the annealed samples is attributed to the suppression of FeGa3 formation in regions containing chromium carbides. Shear stress for fracture, measured by microcantilever tests at the interface between the substrate and the inner matrix of the surface film, showed lower fracture shear stress in the annealed sample, attributed to the presence of larger pores within its microstructure.

Abstract This study proposes an alternative Al4C3-NiCrAlY composite bond coat (BC) “system” to address the current challenges associated with traditional “stacked-horizontal layer” coating designs featuring linear interfacial thermal grown oxide (TGO) layers. The reactivity of Al4C3 with metallic alloy systems remains largely unexplored. This work establishes an initial baseline for the compositional and microstructural characteristics of this novel composite composition in the powder form. The microstructure and phase evolution of spray-dried Al4C3-(25-75 vol.%) NiCrAlY composite powders were examined via controlled-atmosphere heat treatments to establish the steady-state composition and microstructure up to 1300 °C. No significant phase interaction was observed below 1250 °C. Above this temperature, Al diffusion from Al4C3 into NiCrAlY enabled nickel aluminide formation, while free carbon facilitated the precipitation of chromium carbides. The final composition of the composite powder comprised nickel aluminide matrices with internal chromium carbide formations. For powders with higher initial Al4C3 content, nickel aluminide phases also formed as external attachments to the main body of the composite particles.

Thermal annealing effects on the interaction between chromium and silicon carbide in a vacuum environment