In this study, finite element method is applied to simulate thermal spraying of Stellite-6 microparticles on steel substrate. The effects of particle size, substrate pre-heating temperature and spraying angle are investigated on the process output parameters including stress, equivalent plastic strain, penetration depth, and temperature distribution. The simulations are designed and performed based on the Design of Experiments (DOE). Response surface methodology (RSM) is used to explore the relationships between the input factors and responses. The simulation results revealed that penetration depth as the main factor, affecting the bonding strength of coating, is highly dependent on the particle size. Spraying angle is also found to be a significant and effective parameter on the penetration depth. On the other hand, the pre-heating temperature of the substrate is observed to have no substantial effect on the penetration depth. The depth of penetration increases with increasing the particle size and spraying angle, and reaches its maximum value in spraying angle of 90˚.

In this study, high-velocity oxygen-fuel (HVOF) process was applied to produce StelliteWC composite coatings on the surface of carbon steel samples. For this purpose, various amounts of WC powder 0%, 10%, 20% and 30% were mixed with Stellite6. The structural and mechanical behavior of the coatings were evaluated using X-ray diffractometry, scanning electron microscopy, microhardness and roughness test. The results showed that the micro structure of the coatings were composed of a cobalt and chromium solid solution dendritic structure with the interdenderitic phases of cobalt enriched phase, carbides and WC particle. The XRD evaluations indicated that the coatings included Co-rich phase, CoCx, Co3W3C, Co6W6C as well as Cr23C6 and Cr7C3 carbides. Also, It was found that the hardness was increased, the adhesion was improved and the porosity was decreased by increasing the tungsten carbide as reinforcement.

This paper deals with the investigation of the microstructure and hardness of steel samples cladded with satellite 6-WC composites by using gas tungsten arc welding (GTAW) process. For this purpose, steel samples were coated with unreinforced and reinforced stellite (by 20, 30 and 40 wt.% WC). The cladded samples were evaluated by metallographic studies, microhardness measurement and X-ray diffraction analysis. In order to reduce dilution and to increase the hardness, samples were coated by two layers of similar chemical composition. The results indicated that in samples cladded by reinforced stellite, with an increase in tungsten carbide content, the amount of hypoeutectic phase (g+ (g+WC)) increased. This is accompanied by an increase in hardness.

Thermal fatigue (heat checking), mechanical fatigue, wear and plastic deformation of critical areas of hot forging dies at working temperatures are the main mechanisms that reduce their lifetime. During forging processes the surfaces of the dies reach temperatures of 700-800°C.Therefore, hardfacing of these areas with nonferrous elevated temperature hardfacing alloys such as Stellite 6 can improve the performance and lifetime of the dies, many times. Hot hardness, galling resistance, hot corrosion and oxidation resistance, adhesive wear resistance, low friction coefficient and absence of allotropic transformation up to 1100°C are the most important properties of Stellite 6. H11 tool steel is widely used as hot forging die material. This steel because of its high alloy contents and, therefore, its hardenability is very sensitive to high cooling rates involved during welding cycles and hydrogen induced cracking (HIC). For this reason, in this research hardfacing parameters of Hl1 tool steel with Stellite 6 in TIG welding method have been investigated. According to the results, hardfacing of this steel in annealed hardfaced condition isn't feasible and it is recommended that preheating and intermediate temperatures during the hardfacing cycle between 310-370°C. The suitable current for TIG hardfacing of this steel by jp3.2 mm filler rod was determined to be 80-85 amperes for the first layer and 90-100 amperes for upper layers. The minimum thickness for obtaining maximum hardness in the hard facing layer (41-42 HRC) under these conditions was determined to be 3mm. It is recommended that the effective heat input for hardfacing of this steel under three-body heat transfer conditions would be less than 455kJ/m. It is also recommended that the Dt8®5 of H11 tool steel hardfacing cycle would be in the range 6 to 15.3s. Finally it is recommended that H11 hardfaced tool steel would be stress relived in the range 425 -500°C for 1 hour per 30mm base metal thickness.

Two stellite layers were produced as protective coatings by a 1.5 Kw CO2 continous wave laser remelting of the stellite 6 powders on plates of AISI 420 martensitic stainless steel in Ar environment and investigated experimentally. Scanning electron microscopic microphotographs and EDS analysis reveal a strong metallurgical bond between the substrate and coating as well as the structural homogeneity along the depth of the layers which is characterized by a chemical composition close to that of the powder. The laser clad layers show a dendritic and fine grained structure with a minor presence of impurities. For the coatings an improvement of mechanical properties such as the wear resistance and microhardness values compared to those of substrate is observed. Also it is obtained that corrosion resistance is increased so much.

CMT process is a new developed gas metal arc welding (GMAW) process which has low dilution and heat input. This method is useful for expensive electrodes which are used in surfacing. In this research 1, 2 and 3 layer of flux cored Stellite 6 is deposited on A516-Grade 70. Same type of this steel with hard faced Stellite 6 is widely used in oil, gas and petrochemical industries especially where there is a need for wear and oxidation resistance at high temperatures. Chemical composition of layers is explored and the changes in dilution and iron content versus layer number and final thickness of deposited weld are investigated. Similar samples were prepared with conventional GMAW process for comparison. The results showed that heat affected zone (HAZ) in CMT samples are thinner and reduces by 28% which means less heat input in this process. In CMT process Dilution and weld penetration are 39% and 41% respectively less than conventional welding process. By using this method, the desired chemical composition is achievable with less number of thinner layers and leads to reduction of welding electrode consummation.

In this study, laser direct deposition was employed to fabricate a functionally graded transition between 17‑4PH stainless steel and Stellite 6. Specimens were designed and produced such that the chemical composition varied incrementally from 100% 17‑4PH to 100% Stellite 6, with each step involving a 25% decrease in the 17‑4PH content and a corresponding 25 % increase in Stellite 6. Microstructural evolution and elemental distribution were characterized by scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), while mechanical properties were assessed via Vickers microhardness testing and uniaxial tensile tests. The microstructural analysis revealed a needle‑like martensitic matrix in the substrate, which transformed into cellular dendrites upon reaching the 25% Stellite 6 layer. As the Stellite 6 fraction increased, along with corresponding rises in Cr and W content, grain boundaries broadened and carbides accumulated within interdendritic regions. At the 50% composition, oriented columnar dendrites became prominent, and at higher Stellite 6 levels the dendritic structure refined further, ultimately evolving into an equiaxed morphology. Microhardness measurements showed a continuous increase from approximately 300 HV in the 17‑4PH substrate to 490 HV in the pure Stellite 6 layer. Tensile testing demonstrated that both yield strength (σᵧ) and ultimate tensile strength (σᵤ) remained within 1102–1159 MPa across all compositions, with no evidence of brittle phases or manufacturing defects. Elongation increased from 7% in pure Stellite 6 to 19% in pure 17‑4PH, with the 50%–50% gradient exhibiting an optimal balance of strength and ductility (14.5% elongation).

In this paper microstructure, phase formation and Vickers hardness profile of the hardfaced layer, Co-based alloys (Stellite-6) filler metal on 410 martensitic stainless steel specimens with 309 austenitic stainless steel interlayer were investigated. Gas Tungsten Arc Welding (GTAW) cladding was carried out for deposition. The specimens were investigated by an X-ray diffractometer, energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM) and hardness test. According to the analyzed results, the microstructure of the clad layer consists of eutectic structure, and undissolved carbides dispersed in the matrix of the Co-based alloy with dendritic structure. The dendrites have epitaxial growth. Diffusion of carbon from the liquid Stellite to the austenitic stainless steel took place along grain boundaries resulting in the formation of chromium carbide “arms” that penetrated along the austenite grain boundaries in the interfacial region. The dilution of the clad layer by Fe from the substrate decreases hardness, wear and corrosion resistance. The interlayer resulted in a decrease in the dilution of Fe and increase in hardness.

Stellite-6 alloy was deposited on a SS316 stainless steel substrate by Electro-Spark Deposition; subsequently, the thickness of deposition layer was around 100 ± 10 micron. High Energy Shot Peening process was applied to improve coated layer properties. Microstructure, chemical composition, micro hardness variation in cross sections, wear properties and visual check for discontinuities of coated layer were studied by employing Field Emission Scanning Electron Microscopy, Optical Microscopy, EDS line scan and pin on disk wear test, before and after the high energy shot peening process. The results show decreasing the surface roughness from 14 to 4.5 micron and improving the micro-hardness of coated layer from 450 to 540 HVN due to High Energy Shot Peening process on the Electro-Spark Deposition coated layers. On the other hand, the wear properties of the coating are improved, the number of defects such as porosities is reduced, and micro-cracks and defects in melts are healed due to compressive residual stress and severe wax deformation.

In this paper the microstructure, phase formation and Vickers hardness profile of the hardfaced layer of Stellite-6 filler metal on carbon steel were investigated without and with martensitic stainless steel and austenitic stainless steel interlayer. Gas Tungsten Arc Welding (GTAW) cladding was carried out for deposition. The specimens were investigated by the X-ray diffractometer (XRD), energy dispersion spectroscopy (EDS), scanning electron microscopy (SEM) and microhardness test. The results show that the microstructure of these claddings includes chromium carbide phases dispersed in the matrix of the Co-based alloy with a dendritic structure. With the increasing of Stellite layers and interlayer, hardness increased and dilution decreased. The dilution of the clad layer by Fe from the substrate decreases hardness, wear and corrosion resistance. The interlayer resulted in a decrease in the dilution of Fe and increase in hardness.