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Journal articles on the topic 'Stellites'
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1
Hasan, Md Shahanur, Abdul Md Mazid, and Richard Clegg. "The Basics of Stellites in Machining Perspective." International Journal of Engineering Materials and Manufacture 1, no. 2 (December 19, 2016): 35–50. http://dx.doi.org/10.26776/ijemm.01.02.2016.01.
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Stellites are cobalt (Co)-based superalloys available in two main combinations: (a) a Tungsten (W) group with composition of Co-Cr-W-C, and (b) a Molybdenum (Mo) group containing Co-Cr-Mo-C. Stellites possess outstanding corrosion resistance, oxidation resistance, wear resistance, heat resistance, and low magnetic permeability. Components made of stellites work well in highly corrosive environments and maintain these advantageous properties at elevated temperatures. Components made of stellites are widely used in the oil and gas, automotive, nuclear power, paper and pulp, chemical and petrochemical, refineries, automobile, aerospace and aircraft industries. By virtue of their nonmagnetic, anticorrosive and non-reactivity to human body-fluid properties, stellites are used in medical surgery and in surgical tools, tooth and bone implants and replacements, heart valves, and in heart pacemakers. The hardness range of stellites is from 32 to 55 HRC, which makes stellites brittle materials but they have a low Young’s modulus. Due to their high hardness, dense but non-homogeneous molecular structure and lower thermal conductivity, machining operations for parts made of stellites are extremely difficult, categorising stellites as difficult-to-machine materials like Ti-alloys, inconels, composites and stainless steels. Usually, machine components made of stellites are produced by a deposition method onto steel substrates instead of expensive solid stellite bars. The rough surfaces of deposited stellites are then finished by grinding, rather than some other economic machining process, which is costly and time-consuming, making stellite products very expensive. This paper provides a basic overview of stellites applicable in engineering, their significances and specific applications, advantages and disadvantages in respect of machining processes.A brief review on experimental research on economically rational cutting parameters for turning operations of Stellite 6 using coated carbide inserts is presented in this paper. Interesting facts on the residual stresses induced by machining processes in Stellite 6 are revealed and analysed. The microhardness variation of machined surfaces of stellite 6 using different tool geometries is investigated in this research review. It is revealed that coated carbide inserts with a medium-size nose radius perform better in respect of hardness changes and heat generation, producing minimum phase changes on machined surfaces of stellite 6.
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Hasan, Md Shahanur, Md Mazid Abdul, and Richard E. Clegg. "Optimisation of the Machining of Stellite 6 PTA Hardfacing Using Surface Roughness." Key Engineering Materials 443 (June 2010): 227–31. http://dx.doi.org/10.4028/www.scientific.net/kem.443.227.
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Stellites are cobalt based super alloys. By virtue of their excellent physio-mechanical properties, stellites are highly regarded engineering materials. Stellites posses high corrosion resistance and wear resistance properties. This study investigates the Stellite deposition process and machinability of Stellite 6 deposited on steel subtrate. Stellite 6 was deposited onto a 4140 bar using a plasma transfer arc (PTA) system and machinability was assessed on the basis of surface roughness. A series of turning operations have been carried out on a conventional lathe using coated carbide inserts and surface roughness was evaluated by Stylus type Surtronic3+ instrument. The values of surface roughness were plotted against different cutting speed, feed rate and depth of cut to display the results in graphical forms. Optimal cutting regimes were established against the best values of surface roughness.
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Szala, Mirosław, Dariusz Chocyk, Anna Skic, Mariusz Kamiński, Wojciech Macek, and Marcin Turek. "Effect of Nitrogen Ion Implantation on the Cavitation Erosion Resistance and Cobalt-Based Solid Solution Phase Transformations of HIPed Stellite 6." Materials 14, no. 9 (April 29, 2021): 2324. http://dx.doi.org/10.3390/ma14092324.
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From the wide range of engineering materials traditional Stellite 6 (cobalt alloy) exhibits excellent resistance to cavitation erosion (CE). Nonetheless, the influence of ion implantation of cobalt alloys on the CE behaviour has not been completely clarified by the literature. Thus, this work investigates the effect of nitrogen ion implantation (NII) of HIPed Stellite 6 on the improvement of resistance to CE. Finally, the cobalt-rich matrix phase transformations due to both NII and cavitation load were studied. The CE resistance of stellites ion-implanted by 120 keV N+ ions two fluences: 5 × 1016 cm−2 and 1 × 1017 cm−2 were comparatively analysed with the unimplanted stellite and AISI 304 stainless steel. CE tests were conducted according to ASTM G32 with stationary specimen method. Erosion rate curves and mean depth of erosion confirm that the nitrogen-implanted HIPed Stellite 6 two times exceeds the resistance to CE than unimplanted stellite, and has almost ten times higher CE reference than stainless steel. The X-ray diffraction (XRD) confirms that NII of HIPed Stellite 6 favours transformation of the ε(hcp) to γ(fcc) structure. Unimplanted stellite ε-rich matrix is less prone to plastic deformation than γ and consequently, increase of γ phase effectively holds carbides in cobalt matrix and prevents Cr7C3 debonding. This phenomenon elongates three times the CE incubation stage, slows erosion rate and mitigates the material loss. Metastable γ structure formed by ion implantation consumes the cavitation load for work-hardening and γ → ε martensitic transformation. In further CE stages, phases transform as for unimplanted alloy namely, the cavitation-inducted recovery process, removal of strain, dislocations resulting in increase of γ phase. The CE mechanism was investigated using a surface profilometer, atomic force microscopy, SEM-EDS and XRD. HIPed Stellite 6 wear behaviour relies on the plastic deformation of cobalt matrix, starting at Cr7C3/matrix interfaces. Once the Cr7C3 particles lose from the matrix restrain, they debond from matrix and are removed from the material. Carbides detachment creates cavitation pits which initiate cracks propagation through cobalt matrix, that leads to loss of matrix phase and as a result the CE proceeds with a detachment of massive chunk of materials.
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Cabrol, Elodie, Christine Boher, Vanessa Vidal, Farhad Rezai-Aria, and Fabienne Touratier. "A Wear Damage Assessment of High Temperature Forging Tool." Advanced Materials Research 966-967 (June 2014): 103–10. http://dx.doi.org/10.4028/www.scientific.net/amr.966-967.103.
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High temperature forging tools are highly damaged by wear shearing under cyclic loading which reduces the life of tools. In real conditions, depending upon the tool areas, the level of wear can change. The surfaces of tools can be treated by cobalt-based hardfacing using different welding processes. This study focuses on tribological damages of Stellite 21 deposited by MIG process. Wear tests are carried out at room and high temperature on a ring on disc tribometer under high normal load. Different testing conditions are examined. The surface plastic strain due to the friction shear stresses is demonstrated by different methods like SEM observations, micro-hardness measurements and XRD analyses. More particularly, it is shown that the initial (200) crystallographic preferred orientation due to the welding process is modified into (111) crystallographic preferred orientation due to shear stresses regardless the loading. Moreover, a relationship between the gradient of the plastic shear strain at the friction subsurface and the level of the micro-hardness measurement has been established. In regard of the results, when the shear strain exceeds a threshold, the micro-hardness measurement is stabilised. The ultimate value could be induced by the stacking fault energy that is considered as weak in Stellites.
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Atkinson, Helen V. "Alloys for Semi-Solid Processing." Solid State Phenomena 192-193 (October 2012): 16–27. http://dx.doi.org/10.4028/www.scientific.net/ssp.192-193.16.
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The main alloys which have been semi-solid processed commercially are based on aluminium (particularly the cast compositions) and magnesium. There is a strong drive to broaden the range of alloys to the wrought compositions for aluminium, more creep-resistant magnesium recipes and to higher temperature alloys such as those based on copper, steels, stellites and cast irons. This paper will summarise the issues with such development including the scientific and practical issues for alloy design and the thermodynamic prediction of alloys suitable for semi-solid processing. After an initial introduction to semi-solid processing routes, the most important alloy systems for semi-solid processing from a development point of view (aluminium, magnesium, steels and composites- including nanocomposites) will be discussed. The key issues of alloy design specifically for semi-solid processing will be drawn out through the text.
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Peng, Li. "Microstructures and Wear Resistance of Laser Melting Deposited Composites on Ati-Alloy." Advanced Composites Letters 22, no. 2 (March 2013): 096369351302200. http://dx.doi.org/10.1177/096369351302200203.
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This work is based on the dry sliding wear of Stellite 4-FeSi-B4C composites deposited on a TA10 titanium alloy using a Laser melting deposition (LMD) technique, the parameters of which are such as to provide almost crack-free composites with very low porosity. To our knowledge, it is the first time that Stellite4-FeSi-B4C mixed powders are deposited as the hard composites by the LMD technique. Scanning electron microscope results indicate the nanoscale particles and nanorods are produced in such composites. Furthermore, due to the characteristics of the laser technology, the ultrafine nanoscale polycrystalline phases can be easily produced. Compared with a TA10 alloy substrate, the improvements of the micro-hardness and wear resistance are obtained for such composites.
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Ribeiro, Hélio Ormeu, Augusto José de Almeida Buschinelli, Jair Carlos Dutra, and Ana Sofia Clímaco Monteiro D´Oliveira. "Resistência à erosão por cavitação de aços inoxidáveis austeníticos CrMnSiN depositados por PTA." Soldagem & Inspeção 15, no. 2 (June 2010): 121–29. http://dx.doi.org/10.1590/s0104-92242010000200006.
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A erosão por cavitação deteriora componentes em serviço, tais como partes metálicas de bombas de água, válvulas e, em especial, pás de turbinas hidráulicas, sendo nesse último caso responsável por elevados prejuízos ligados tanto aos custos da manutenção direta, como sobretudo às perdas por interrupção na geração de energia elétrica. Dentre os materiais aplicados no reparo por soldagem de danos por cavitação incluem-se aços inoxidáveis tradicionais tipo AISI 308 e 309, aços inoxidáveis ao Co e ligas à base de Co (stellites), caracterizando-se essas últimas pela maior sensibilidade a trincas, dificuldade de esmerilhamento e pelo mais alto custo. Nesse contexto este trabalho buscou formular, depositar e analisar o desempenho de aços inoxidáveis austeníticos CrMnSiN, soldados pelo processo PTA. A resistência à erosão por cavitação foi avaliada segundo a norma ASTM G 32-92. A microestrutura foi caracterizada por microscopia ótica e microscopia eletrônica de varredura e a formação de martensitas α' e ε, induzida pela cavitação, foi avaliada por difração de raios-X. A integridade da superfície dos depósitos foi controlada por END, além disso a dureza e a facilidade de acabamaneto por esmerilhamento serviram como critérios para avaliar os revestimentos soldados. Verificou-se que os revestimentos aplicados por PTA eram livres de trincas de solidificação, com baixa porosidade, boa molhabilidade e adequado acabamento superficial. A melhor liga inoxidável austenítica elaborada (0,03%C; 0,35% N; 13,2%Cr; 11,8% Mn; 2,8%Si; bal %Fe) mostrou uma resistência à erosão por cavitação próxima aquela das principais ligas comerciais.
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J, Hemanandh, Sharmila Hemanandh, S. Ganesan, S. Venkatesh, J. Cyril Praveenraj, and Ashokan Vikram. "Investigation of Bio-Diesel in Uncoated Piston Head Vs Bio-Diesel in Coated Head." IOP Conference Series: Earth and Environmental Science 1100, no. 1 (December 1, 2022): 012014. http://dx.doi.org/10.1088/1755-1315/1100/1/012014.
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Abstract The need for less carbon content in fuel, as well as an increase in energy consumption, has paved the way for the development of alternative fuel for engines. Biodiesel is an environmentally friendly alternative to conventional fuel. Thermal barrier coating reduces heat transfer to the cooling system while the engine is idle and protects engine components from high thermal stresses. This paper investigates the blending of waste fish fry methyl esters in a single cylinder, four stroke DI diesel engine with a stellite-6 coated engine head. In this study, waste fish fry oil (WFFO) was transesterified with methanol and a NaOH catalyst. The methyl esters were obtained, and various test fuels were made (WFFO10, WFFO20, WFFO30) These blended samples were fired up in the DI diesel engine, and performance tests were conducted. Engine characteristics such as brake thermal efficiency (BTE), brake specific fuel consumption (BSFC), and engine emissions were measured for the stellite6 coated cylinder head.
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Mishra, N. K., A. K. Rai, S. B. Mishra, and R. Kumar. "Hot Corrosion Behaviour of Detonation Gun Sprayed Stellite-6 and Stellite-21 Coating on Boiler Steel SAE 431 at 900°C." International Journal of Corrosion 2014 (2014): 1–4. http://dx.doi.org/10.1155/2014/146391.
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Hot corrosion is the serious problem in gas turbines, superheaters, and economizers of coal-fired boilers. It occurs due to the usage of wide range of fuels such as coal, oil, and so on at the elevated temperatures. Protective coatings on boiler steels are used under such environments. In the present investigation, Stellite-6 and Stellite-21 coatings have been deposited on boiler steel SAE 431 by detonation gun method. The hot corrosion performance of Stellite-6 and Stellite-21 coated as well as uncoated SAE 431 steel has been evaluated in aggressive environment of Na2SO4-82%Fe2(SO4)3under cyclic conditions at an elevated temperature of 900°C for total duration of 50 cycles. Thermogravimetric technique was used to approximate the kinetics of hot corrosion. Stellite-6 coating imparted better hot corrosion resistance than Stellite-21 coating in the given environment. Scanning electron microscopy was used to characterize the surface of hot corrosion products.
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Xu, Yang Tao, Tian Dong Xia, Wen Jun Zhao, and Xi Jing Wang. "Corrosion Behavior of Cobalt-Based Stellite 6 Alloy by Combustion Synthesis and Vacuum Induction Melting." Advanced Materials Research 317-319 (August 2011): 1891–95. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.1891.
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Cobalt-based Stellite 6 alloy rely primarily on carbides, forming in the Co matrix and grain boundaries, for their strength and the distribution, size and shape of carbides depend on processing conditions. We have employed microstructure and corrosion behavior of Stellite 6 by combustion synthesis and vacuum induction melting with scanning electron microscopy, electron probe microscopy analysis. The results show that there are significant uniformity on microstructure and corrosion behavior of Stellite 6 by different techniques. The combustion synthesis has more advantages over conventional manufacturing process for Stellite 6.
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Kunimine, Takahiro, Ryusei Miyazaki, Yorihiro Yamashita, Yoshinori Funada, Yuji Sato, and Masahiro Tsukamoto. "Cladding of Stellite-6/WC Composites Coatings by Laser Metal Deposition." Materials Science Forum 941 (December 2018): 1645–50. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1645.
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This study aims to investigate the microstructure and hardness of multi-layered Stellite-6/WC metal-matrix composites coatings on metallic substrates cladded by laser metal deposition (LMD) for improvement of wear and corrosion resistances. As coating materials, Stellite-6 and WC-12wt.%Co powders were selected. Powder mixtures having various mixing-ratios of Stellite-6 and WC-12wt.%Co were provided vertically on S45C substrates by controlling powder feeding rates of the two powder feeders, individually. Stellite-6/WC composites which consist of three layers with different compositions were cladded on the S45C substrates by laser melting. Cross-sectional microstructure observation was carried out by using an optical microscope (OM). Vickers microhardness tests were conducted to evaluate hardness of the cladding layers and substrates. The experimental results demonstrate that hard multi-layered Stellite-6/WC metal-matrix composites coatings were successfully cladded on the S45C substrates. Property gradients in the Stellite-6/WC composites could be made due to the position-dependent chemical composition and microstructure made by controlling powder feeding rates of an LMD system.
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NAPADŁEK, Wojciech, Adam WOŹNIAK, and Wojciech CHRZANOWSKI. "STUDY OF SELECTED USABLE PROPERTIES OF THE TOP LAYERS OF WELD OVERLAYS PRODUCED BY LASER TECHNOLOGY FOR APPLICATIONS IN THE POWER INDUSTRY." Tribologia 277, no. 1 (March 1, 2018): 81–88. http://dx.doi.org/10.5604/01.3001.0011.9932.
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The paper presents the results of laboratory tests of test specimens produced by multi-layer laser padding alloy Stellit Co-6 powder on a substrate with heat-treated X22CrMoV12-1 alloy steel. Multilayer laser padding was performed on a TRUMPF TruLaser Cell 3008. The formed weld overlays surface was studied using an optical microscope. Selected usable properties, such as surface topography, microstructure, hardness and erosion resistance were studied. During the analysis, areas of cross-sections test specimens after multilayer laser padded, in the connection zone of the substrate material with weld overlay, no cracks and no discontinuities in weld overlay were found in the substrate. As a result of conducted experiments, regular, repetitive weld overlays with characteristic directional crystallization were obtained. A microstructure with different growth directions with respect to the surface of the substrate shaped coniferous dendrites was obtained. The hardness of the weld overlays was in the range from 420 to 620 HV0.1, and in the heat affected zone, in the range of 320 to 420 HV0.1. Significant increases in erosion resistance of the surface layer of Stellite type Co-6 weld overlay produced by laser in comparison with the parent material after hardening were found.
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Santiago-Bautista, L., H. M. Hdz-García, M. Alvarez-Vera, R. Muñoz-Arroyo, J. L. Acevedo-Dávila, F. J. Vázquez-García, and J. Jorge Ruiz Mondragon. "Effects of tic Nanostructured Overlays on D2 Steels by PTA." MRS Advances 2, no. 64 (2017): 4041–47. http://dx.doi.org/10.1557/adv.2017.603.
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AbstractTwo metal fillers with TiC nanoparticles (TiC NPs) of less than 100 nm for the overlay process is an alternative to hardfacing for treating surfaces subjected to severe wear. In this work, the effect of tribological behavior for TiC NPs addition on two Co-based filler materials, as well as the dilutions, was studied. Mixtures of Co-based filler metals without and with 0.5% and 2% TiC NPs were deposited onto D2 steel plates using PTA (Plasma Transferred Arc). The BET surface area was 0.17 m2 g-1 and 0.31 m2 g-1, respectively, for Stellite 6 and 12. The distribution of ca 23% macroporous for Stellite 6 was sufficient to get inside the TiC NPs, as well as in the case of Stellite 12, with a pore distribution of ca 13%. Stellite 12 has an increase in the dilutions (70%) and enthalpies showed endothermic reactions. Stellite 6 with NPs was determined to be most effective in increasing the wear resistance.
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Kusmoko, Alain, Druce P. Dunne, and Hui Jun Li. "Wear Behaviour of Stellite 6 Coatings Produced on an Austenitic Stainless Steel Substrate by Laser Cladding Using Two Different Heat Inputs." Applied Mechanics and Materials 619 (August 2014): 13–17. http://dx.doi.org/10.4028/www.scientific.net/amm.619.13.
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Stellite 6 was deposited by laser cladding on an austenitic stainless steel substrate (ASS) with energy inputs of 1 kW (ASS 1) and 1.8 kW (ASS 1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the austenitic stainless steel substrate with the lower heat input (ASS 1). Further, the Stellite coating for ASS 1 was significantly harder than that obtained for ASS 1.8. The wear test results showed that the weight loss for ASS 1 was much lower than for ASS 1.8. It is concluded that the lower hardness of the coating for ASS 1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
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Kusmoko, Alain, Druce Dunne, and Hui Jun Li. "Evaluation of Two Different Energy Inputs for Deposition of Stellite 6 by Laser Cladding on a Martensitic Stainless Steel Substrate." Advanced Materials Research 1119 (July 2015): 628–32. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.628.
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Stellite 6 was deposited by laser cladding on a martensitic stainless steel substrate with energy inputs of 1 kW (MSS-1) and 1.8 kW (MSS-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was assessed using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the MSS steel substrate with the lower heat input (MSS-1). Further, the Stellite coating for MSS-1 was significantly harder than that obtained for MSS-1.8. The wear test results indicated that the weight loss for MSS-1 was much lower than for MSS-1.8. It is concluded that the lower hardness of the coating for MSS-1.8, markedly reduced the wear resistance of the Stellite 6 coating.
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Kusmoko, Alain, Druce Dunne, Hui Jun Li, and David Nolan. "Study of Laser Cladding of Stellite 6 on Nickel Superalloy Substrate with Two Different Energy Inputs." Advanced Materials Research 896 (February 2014): 600–604. http://dx.doi.org/10.4028/www.scientific.net/amr.896.600.
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Stellite 6 was deposited by laser cladding on a nickel superalloy substrate (NIS) with energy inputs of 1 kW (NIS 1) and 1.8 kW (NIS 1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the nickel superalloy substrate with the lower heat input (NIS 1). Further, the Stellite coating for NIS 1 was significantly harder than that obtained for NIS 1.8. The wear test results showed that the weight loss for NIS 1 was much lower than for NIS 1.8. It is concluded that the lower hardness of the coating for NIS 1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
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Kusmoko, Alain, Druce Dunne, Hui Jun Li, and David Nolan. "Laser Cladding of Wear Resistant Stellite 6 Coating on P22 Steel Substrate with Two Different Energy Inputs." Advanced Materials Research 911 (March 2014): 97–101. http://dx.doi.org/10.4028/www.scientific.net/amr.911.97.
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Stellite 6 was deposited by laser cladding on a P22 steel substrate with energy inputs of 1 kW (P22-1) and 1.8 kW (P22-1.8). The chemical compositions and microstructures of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the P22 steel substrate with the lower heat input (P22-1). Further, the Stellite coating for P22-1 was significantly harder than that obtained for P22-1.8. The wear test results showed that the weight loss for P22-1 was much lower than for P22-1.8. It is concluded that the lower hardness of the coating for P22-1.8, markedly reduced the wear resistance of the Stellite 6 coating.
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Nekrasov, Roman, Andrei Galinskii, and Olga Tempel. "Stellite Surfacing Technology." Materials Today: Proceedings 11 (2019): 101–6. http://dx.doi.org/10.1016/j.matpr.2018.12.114.
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Usoltcev, Evgenii A., Evgenii L. Furman, and Igor E. Furman. "Development of Cast Cobalt Alloy for SRP Valve Pairs." Solid State Phenomena 316 (April 2021): 502–8. http://dx.doi.org/10.4028/www.scientific.net/ssp.316.502.
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The work is devoted to studying of possibility to manufacture cast ball valves of sucker rod oil pumps instead of those manufactured by the powder metallurgy method from Stellite 20 alloy. It is shown that Stellite 20 cast alloy includes about 20% μ and σ brittle phases, destruction whereof, in case of impact-abrasion wear, when excavating oil, leads to quick failure of the valve pair. A new cast cobalt alloy not containing brittle phases has been developed instead of Stellite 20 alloy, which allowed to improve wear resistance of cast valve pairs to the level of valves produced by the powder metallurgy method.
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Zhu, Zhiyuan, Chun Ouyang, Yanxin Qiao, and Xiaowei Zhou. "Wear Characteristic of Stellite 6 Alloy Hardfacing Layer by Plasma Arc Surfacing Processes." Scanning 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/6097486.
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The microstructure and wear resistance of Stellite 6 alloy hardfacing layer at two different temperatures (room temperature and 300°C) were investigated by plasma arc surfacing processes on Q235 Steel. Tribological test was conducted to characterize the wear property. The microstructure of Stellite 6 alloy coating mainly consists of α-Co and (Cr, Fe)7C3 phases. The friction coefficient of Stellite 6 alloys fluctuates slightly under different loads at 300°C. The oxide layer is formed on the coating surface and serves as a special lubricant during the wear test. Abrasive wear is the dominant mechanism at room temperature, and microploughing and plasticity are the key wear mechanisms at 300°C.
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Li, Zixiang, Yinan Cui, Jie Wang, Changmeng Liu, Jiachen Wang, Tianqiu Xu, Tao Lu, et al. "Characterization of Microstructure and Mechanical Properties of Stellite 6 Part Fabricated by Wire Arc Additive Manufacturing." Metals 9, no. 4 (April 24, 2019): 474. http://dx.doi.org/10.3390/met9040474.
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Stellite 6 alloy has excellent wear resistance, corrosion resistance, and oxidation resistance, however the difficulties in traditional processing limit its wide application. Additive manufacturing technology that has emerged in recent years is expected to provide a new way for the processing of stellite 6 alloy. In this study, two square thin-walled stellite 6 parts were fabricated through the wire arc additive manufacturing technology. At the same time, the effect of stress relief annealing on the mechanical performance of the fabricated stellite 6 part was studied and compared with the corresponding casting part. The results indicate that the additive manufacturing stellite 6 components exhibit satisfactory quality and appearance. Moreover, the microstructure of the additive manufacturing part is much finer than that of the casting part. From the substrate to the top region of the additive manufacturing part, the morphology of the dendrites changes from columnar to equiaxed, and the hardness increases firstly and then decreases gradually. In addition, the average hardness of the additive manufacturing part is ~7–8 HRC higher than the casting part. The ultimate tensile strength and yield strength is ~150MPa higher than the casting part, while the elongation is almost the same. The stress relief annealing has no significant effect on the hardness of the AM part, but it can slightly improve the strength.
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Kołodziejczak, Paweł, Mariusz Bober, and Tomasz Chmielewski. "Wear Resistance Comparison Research of High-Alloy Protective Coatings for Power Industry Prepared by Means of CMT Cladding." Applied Sciences 12, no. 9 (April 30, 2022): 4568. http://dx.doi.org/10.3390/app12094568.
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In this study, four protective coating materials: Inconel 718, Inconel 625, Alloy 33 and Stellite 6 were deposited on 16Mo3 steel tubes by means of CMT (Cold Metal Transfer), as an advanced version of MAG (Metal Active Gas) welding method. In the next step, the surface of the deposited coating was remelted by means of TIG (Tungsten Inert Gas) welding method. SEM microstructure of coatings–substrate has been reported, and an EDX-researched chemical composition of the coatings was compared to the nominal chemical composition. The hardness distribution in the cross-section was performed, which revealed that among investigated coatings, Stellite 6 layer is the hardest, at about 500 HV0.2. Other materials such as Inconel 625, Inconel 718 and Alloy 33 represented a cladded zone hardness about 250 HV0.2. Stellite 6 layer had the lowest wear resistance in the dry sand/rubber wheel test, and Stellite 6 layer had the highest wear resistance in the erosive blasting test. This proved the existence of different wear mechanisms in the two test methods used. In the dry sand/rubber wheel test, the Alloy 33 and Inconel 718 only represented higher wear resistance than substrate 16Mo3 steel. In abrasive blasting tests all coatings had higher wear resistance than 16Mo3 steel; however, Stellite 6 coatings represented an approximately 5 times higher durability than other investigated (Inconel 625, Inconel 718, and Alloy 33) coatings.
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CHAO, NING LABBISH, ALFREDO CARVALHO-FILHO, and JONAS DE ANDRADE SANTOS. "Five new species of Western Atlantic stardrums, Stellifer (Perciformes: Sciaenidae) with a key to Atlantic Stellifer species." Zootaxa 4991, no. 3 (June 24, 2021): 434–66. http://dx.doi.org/10.11646/zootaxa.4991.3.2.
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Five new species of Stellifer are described from the Caribbean Sea and tropical southwestern Atlantic. Among the previously recognized stelliferine genera, Stellifer is unique by having a pair of variably developed appendages on the posterior margin of the anterior gas chamber, which is lacking in Bairdiella, Corvula, Elattarchus, Odontoscion and Ophioscion. However, recent genetic studies indicated that Stellifer and Ophioscion are not monophyletic. The genus Ophioscion Gill, 1863 is recognized herein as a junior synonym of Stellifer Oken, 1817. Of the five new species described, Stellifer cervigoni n. sp., S. collettei n. sp., and S. musicki n. sp. have a pair of knob-like diverticula along the posterior margin of the anterior gas chamber, which is absent in S. macallisteri n. sp., and S. menezesi n. sp. Stellifer cervigoni n. sp. is found along the southern Caribbean coast of Colombia and Venezuela; it can be distinguished from other species by having a jet-black roof of mouth and inner opercular lining. Stellifer collettei n. sp. is found from Surinam to southeastern Brazil, while S. musicki n. sp. is endemic to northern Brazil. Stellifer macallisteri n. sp. has an oblique, terminal mouth and it is found in Colombia, Venezuela and Dominican Republic. Stellifer menezesi n. sp. has a subterminal mouth and is found from northeastern to southeastern Brazil. These results bring the number of valid species of Stellifer in the Atlantic to 18, and a key to the identification of these species is included.
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Singh, Raghuvir, S. K. Tiwari, and Suman K. Mishra. "Cladding of Tungsten Carbide and Stellite Using High Power Diode Laser to Improve the Surface Properties of Stainless Steel." Advanced Materials Research 585 (November 2012): 498–501. http://dx.doi.org/10.4028/www.scientific.net/amr.585.498.
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Surface engineering is one of the most viable methods, in addition to development of new alloys and equipment design, to minimize degradation due to cavitation erosion, and corrosion. Laser surface cladding is relatively a newer engineering technique to produce metallurgically bonded coating for industrial applications due to its inherent benefits. Present paper reports the results obtained on the laser cladding of stainless steel with tungsten carbide (WC) and stellite alloy powder using high power diode laser (HPDL) at various laser parameters. Cladded specimens were characterized for erosion, and corrosion resistance. Both WC and stellite cladding have increased the erosion resistance of stainless steels. WC cladding was found to reduce the corrosion resistance of steel while stellite showed it to increase significantly.
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Prabhakaran, D., N. Jegadeeswaran, B. Somasundar, and B. S. Raju. "Study on Solid Particle Erosion Studies of Stellite-6 HVOF Coating on Titanium Alloy." Solid State Phenomena 340 (December 23, 2022): 83–88. http://dx.doi.org/10.4028/p-1zf317.
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The present research work explores the possibility of use of HVOF sprayed cermet coating Stellite-6 on gas turbine material Titanium Alloy (Ti-31). The coating is investigated for their resistance to erosion under laboratory conditions. Solid particle erosion studies were conducted using silica sand as the erodent. Erosion studies were done with impact angles of 30º, 60º and 90º. Stellite-6 coating performs better under sand erosion conditions. Stellite-6 coatings undergo damage by brittle mode. Erosion behavior of the substrate materials is ductile and resistance is better than the coating material. SEM microstructures were used for scar produced by the erodent, at 30º, 60º and 90º. impact angles, also indicates that the material damage is due to ploughing and entrapment of silica particles.
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Kusmoko, Alain, and Hui Jun Li. "Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding." Advanced Materials Research 1119 (July 2015): 640–44. http://dx.doi.org/10.4028/www.scientific.net/amr.1119.640.
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Stellite 6 was deposited by laser cladding on a 9Cr-1Mo (P91) substrate with energy inputs of 1 kW (P91-1) and 1.8 kW (P91-1.8). The chemical compositions, microstructures and surface roughnesses of these coatings were characterized by atomic absorption spectroscopy, optical microscopy, scanning electron microscopy and atomic force microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was evaluated using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the 9Cr-1Mo (P91) steel substrate with the lower heat input (P91-1). Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91-1.8. The wear test results indicated that the weight loss for P91-1 was much lower than for P91-1.8. The surface topography data indicated that the surface roughness for P91-1 was much lower than for P91-1.8. It is concluded that the lower hardness of the coating for P91-1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.
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Kannan, Mathivanan, Thirumalaikumarasamy Duraisamy, Thirumal Pattabi, and Ashokkumar Mohankumar. "Investigate the corrosion properties of stellite coated on AZ91D alloy by plasma spray technique." Thermal Science, no. 00 (2021): 209. http://dx.doi.org/10.2298/tsci200722209k.
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Stellite alloys are primarily preferred in various component manufacturing industries due to its magnificent mechanical and electrochemical properties. The stellite powder is deposited over the materials by Various thermal spray methods in industries. This research proposed investigating the microstructure and corrosion properties of stellite powder that is deposited on an AZ91D magnesium alloy substrate by atmospheric plasma spraying process. SEM, optical microscopy, and atomic force microscopy are typical of the coatings. Immersion experiments in sodium chloride conditions are conducted at varying pH levels, chloride ion concentration, and exposure time. In addition, XRD examined the phase change properties of the powder and sprayed condition of coatings along with corrosion testing. The corrosion experiments were conducted to establish several regression models based on the central composite design and the response surface process. The accuracy of the regression models was sufficient to allow correlations between input parameters and responses through variance analysis. It was found that the pH value significantly influences the corrosion behaviour of stellite coatings followed by other parameters such as chloride ion concentration and exposure time; even in corrosion tests, plasma-sprayed coatings performed better.
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Di, Juan, Shunsen Wang, Xiaojiang Yan, Xihang Jiang, Jinyi Lian, Zheyuan Zhang, and Yonghui Xie. "Experimental Research on Water Droplet Erosion Resistance Characteristics of Turbine Blade Substrate and Strengthened Layers Materials." Materials 13, no. 19 (September 25, 2020): 4286. http://dx.doi.org/10.3390/ma13194286.
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In this paper, the water droplet erosion (WDE) performance of typical martensitic precipitation substrate 0Cr17Ni4Cu4Nb in steam turbine final stage, laser solid solution strengthened sample, laser cladding sample and brazed stellite alloy samples have been studied based on a high-speed rotating waterjet test system. The WDE resistance of several materials from strong to weak is in sequence: Brazed stellite alloy > laser cladding sample > laser solid solution sample > martensitic substrate. Furthermore, the WDE resistance mechanism and the failure mode of brazed stellite alloy have been revealed. It is found that the hard carbide in the stellite alloy is the starting point of crack formation and propagation. Under the continuous droplet impact, cracks grow and connect into networks, resulting in the removal of carbide precipitates and WDE damage. It is proved that the properties of the Co-based material itself is the reason for its excellent WDE resistance. And the carbides have almost no positive contribution to its anti-erodibility. These new findings are of great significance to process methods and parameter selection of steam turbine blade materials and surface strengthened layers.
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Rao, K. Prasad, R. Damodaram, H. Khalid Rafi, G. D. Janaki Ram, G. Madhusudhan Reddy, and R. Nagalakshmi. "Friction surfaced Stellite6 coatings." Materials Characterization 70 (August 2012): 111–16. http://dx.doi.org/10.1016/j.matchar.2012.05.008.
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Park, Chang-Kyoo, Jung-Hoon Lee, Nam-Hyun Kang, and Eun-Joon Chun. "Correlation between Microstructure and Tribological Properties of Laser Surface Heat-Treated Stellite Coatings." Coatings 10, no. 5 (April 28, 2020): 433. http://dx.doi.org/10.3390/coatings10050433.
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To manufacture superior-performance continuous casting mold components, high-velocity oxygen fuel spraying of a Stellite-1 coating was followed by its laser heat treatment at 1373–1473 K using a diode laser. The effects of the laser irradiation conditions on the macro- and microstructural variations along with the hardness and wear resistance within the Stellite-1 coating were evaluated. After the heat treatment, micro-voids within the sprayed coating decreased in number slightly with an increase in the heat treatment temperature. The hardness of the sprayed Stellite-1 coating increased from that of the as-sprayed coating (680 HV) after the laser heat treatment, with a hardness of 860 HV obtained at 1473 K. The cause of the increase in hardness could be the formation of nano-sized W- and Cr-based carbides such as WC, M7C3, and M23C6, as suggested by transmission electron microscopy analysis. The tribological properties of as-sprayed and laser heat-treated samples were investigated by a pin-on-disk tribometer. The laser heat treatment of Stellite-1 coating enhanced wear resistance. This resulted in a lower coefficient of friction and wear rate for the laser heat-treated sample than those for the as-sprayed sample.
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Liu, Rong, Yi Li, and Glenn McRae. "Electrochemical Investigation of Stellite 6 Alloy in Morpholine Corrosive Environment." Materials Science Forum 934 (October 2018): 117–23. http://dx.doi.org/10.4028/www.scientific.net/msf.934.117.
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The corrosion resistance of Stellite 6 alloy in morpholine solution with pH 9.5 is investigated using the electrochemical test method, simulating the amine environment of the boiler feed water service condition in coal power plants. Polarization test is performed on Stellite 6 alloy under the low potential varying from-0.4 VSCE to 1.2 VSCE and is also conducted under a constant high potential (4 VSCE) in order to fail the sample surface. 17-4PH stainless steel, which is also a common material for the application of the boiler feed water in coal power plants, is tested simultaneously under the same conditions for comparison. It is shown that the polarization curve 17-4PH steel from the low potential test has an apparent passivation region indicating a protective oxide film formed on the sample surface, but Stellite 6 only exhibits a tendency to passivate. Both samples after the failure tests under the high potential (4 VSC) are analyzed using SEM/EDX. The surface morphologies indicate that the former is severely corroded in the solution while the latter is less corroded. The corrosion mechanisms of Stellite 6 alloy and 174PH stainless steel in morpholine solution are discussed with assistance of the Pourbaix diagrams.
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Kusmoko, Alain, D. Dunne, H. Li, and D. Nolan. "Laser Cladding of Stainless Steel Substrates with Stellite 6." Materials Science Forum 773-774 (November 2013): 573–89. http://dx.doi.org/10.4028/www.scientific.net/msf.773-774.573.
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Stellite 6 coatings were produced using laser cladding of two different steel substrates (martensitic and austenitic stainless steels). The chemical composition and microstructure of these coatings were characterized by atomic absorption spectroscopy, optical microscopy and scanning electron microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was examined using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the martensitic stainless steel (SS) substrate. The wear test results showed that the weight loss for the coating on martensitic SS was significantly lower than for the austenitic SS substrate. It is concluded that the higher hardness of the coating on the martensitic SS, together with the harder and more rigid substrate increase the wear resistance of the Stellite 6 coating.
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S.R., Karthik, Neelakanta V. Londe, Raviraj Shetty, Rajesh Nayak, and Adithya Hedge. "Optimization and prediction of hardness, wear and surface roughness on age hardened stellite 6 alloys." Manufacturing Review 9 (2022): 10. http://dx.doi.org/10.1051/mfreview/2022008.
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Growing demand for Stellite 6 alloys due to its attractive properties such as superior strength, toughness, wear resistance, fracture resistant characteristics, and their exceptional resistance to corrosion has made them applicable in industrial as well as commercial applications, such as aerospace industries, nuclear waste storage, automobile industries and surgical implantation. However, in spite of these applications, automotive part manufacturers mainly (Bearing Materials) are looking for a comprehensive study, such as mechanics of friction and the relationship between friction and wear. Hence in this paper, an attempt has been made to study the tribological behavior such as wear characterization and surface roughness of age hardened Stellite 6 alloys. The main objective of the research is to determine the favorable tribological conditions for improving wear resistant properties and surface roughness on age hardened Stellite 6 alloys. Hence two body wear study and surface roughness study during Wire Electric Discharge Machining (WEDM) of age hardened Stellite 6 alloys based on Analysis of Variance (ANOVA), Taguchi's Design of Experiment (TDOE), Response Surface Methodology(RSM) and Desirability Functional Analysis (DFA) have been used to achieve this goal. From the study it is observed that optimum values for improving hardness, wear and surface roughness values can be easily achieved with less time and cost by adopting the said techniques. •From microstructural observation, as the peak current increases there is larger amount of dendritic carbides and cracking of carbides due to high plastic deformation resulting in thermal softening of Stellite 6 alloy during wire electric discharge machining resulting in better surface roughness values. The second-order model for hardness, wear and surface roughness using response surface methodology can be adopted for predicting for hardness, wear and surface roughness in any experimental domain.
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Kusmoko, Alain, Druce Dunne, and Hui Jun Li. "Dilution and C Content Estimation of Stellite 6 Fabricated on a 1050 Steel Substrate by Laser Cladding." Solid State Phenomena 263 (September 2017): 131–36. http://dx.doi.org/10.4028/www.scientific.net/ssp.263.131.
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Stellite 6 was fabricated by laser cladding on a 1050 steel (MS) substrate with laser powers of 1 kW (MS-1) and 1.8 kW (MS-1.8). The chemical compositions and microstructures of the coatings were analysed by X-Ray Fluoroscense, optical microscopy and scanning electron microscopy. The microhardness of the coatings was examined and the wear mechanism of the coatings was evaluated using a ball-on-plate wear testing machine. The results indicated less cracking and pore development for Stellite 6 coatings applied to the 1050 steel substrate with the lower laser power (MS-1). Moreover, the Stellite coating for MS-1 was significantly harder than that obtained for MS-1.8. The wear test results showed that the weight loss for MS-1 was much lower than for MS-1.8. The evaluations of dilution and calculation of carbon content indicated that MS-1 has lower dilution and higher coating C content than MS-1.8. It is concluded that the lower hardness of the coating for MS-1.8, substantially reduced the wear resistance of the Stellite 6 coating and the lower hardness of the coating for MS-1.8 was due to higher level of dilution and lower coating C content. The coating-substrate couple must be considered in assessing the likely performance of the coating under service conditions.
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Motallebzadeh, Amir, Erdem Atar, and Huseyin Cimenoglu. "Raman spectroscopy characterization of hypo-eutectic CoCrWC alloy tribolayers." Industrial Lubrication and Tribology 68, no. 4 (June 13, 2016): 515–20. http://dx.doi.org/10.1108/ilt-11-2015-0168.
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Purpose This paper aims to study microstructure and high temperature tribological performance of hypo-eutectic CoCrWC hardfacing alloy (Stellite 12) deposited on steel substrate by plasma-transferred arc (PTA) welding technique. Design/methodology/approach Microstructural characterization of the deposited coating was made using electron probe microanalysis, X-ray diffraction and microhardness tester. Dry sliding wear tests were carried out with a ball-on-disc type tribometer at room and elevated temperature. Worn surfaces of the samples were examined by the EDX equipped SEM and Raman spectroscopy. Findings Results revealed that at room temperature and 300°C plasticity dominated wear mechanism was operative. Under oxidation dominated wear conditions (400, 500, 600 and 700°C), testing temperature plays a crucial role on the characteristics of the oxide tribolayers formed on worn surfaces. Development of Cr2O3 in the tribolayer at 600 and 700°C was beneficial in increasing wear resistance of examined coating. Originality/value While the sliding wear performance of Stellite alloys at room temperature has been investigated in details, published studies on tribological behavior of Stellite alloys with varying temperature are scarce. Therefore, the present work was undertaken to study the wear mechanisms and the type of tribolayers formed during sliding wear of PTA welding deposited hypo-eutectic Stellite 12 coating with increasing temperature up to 700°C.
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Česánek, Zdeněk, Jan Schubert, Šárka Houdková, Olga Bláhová, and Michaela Prantnerová. "Deterioration of Local Mechanical Properties of HVOF-Sprayed Stellite 6 after Exposure to High-Temperature Corrosion." Key Engineering Materials 662 (September 2015): 115–18. http://dx.doi.org/10.4028/www.scientific.net/kem.662.115.
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Coating properties determine its behavior in operation. The simulation of future operational conditions is therefore the best quality test. The evaluation during operation is usually not possible to perform, and the coatings are therefore frequently characterized by their physical or mechanical properties. This text deals with the high temperature corrosion of HVOF sprayed Stellite 6 coating and with changes of its local mechanical properties before and after the corrosion testing. High temperature corrosion is defined as a corrosion in the presence of molten salts. In this case, the mixture of salts in composition of 59% Na2(SO)4 with 34.5% KCl and 6.5% NaCl was used. Two exposure temperatures 525 °C and 575 °C were selected and the tests for both temperatures were performed in the time interval of 168h in the autoclave. The coating with salt mixture layer was analyzed using scanning electron microscopy and nanoindentation. The high temperature resistance of Stellite 6 coating was evaluated according to the changes in the coating surface and by the occurrence of individual phases formed on the coating surface during the test. Generally, it can be said that the Stellite 6 alloys deposited by HVOF technology show selective oxidation under the salt film. This fact was also proved in this study. Furthermore, the nanoindentation measurements of Stellite 6 coating were performed before and after the corrosion testing. These measurements were used to evaluate the change of local mechanical coating properties.
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Alhattab, Ali Abdul Munim, Shaikh Asad Ali Dilawary, Amir Motallebzadeh, Cevat Fahir Arisoy, and Huseyin Cimenoglu. "Effect of electron beam surface melting on the microstructure and wear behavior of Stellite 12 hardfacing." Industrial Lubrication and Tribology 71, no. 5 (July 8, 2019): 636–41. http://dx.doi.org/10.1108/ilt-05-2018-0182.
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PurposeThe purpose of this study is to investigate the effect of electron beam surface melting (EBSM) on the properties of Plasma Transfer Arc (PTA) deposited Stellite 12 hardfacing.Design/methodology/approachFor this purpose, structural characterization and dry sliding wear tests have been conducted on the hardfacings at room temperature. The wear tracks formed on the surfaces of the hardfacings were examined by a stylus-type profilometer and a scanning electron microscope.FindingsRefinement of the matrix and the carbides following EBSM process led to about 15 per cent increment in hardness as compared to PTA state. Despite an increase in the surface hardness, EBSM’ed hardfacing exhibited about 50 per cent lower sliding wear resistance than PTA hardfacing against alumina ball. According to the worn surface examinations, reduction in the wear resistance of Stellite 12 after EBSM process has been associated with the extensive refinement of the carbides which made them easier to be removed from the matrix during the sliding contact.Originality/valueThe authors of current study have applied EBSM to PTA deposited Stellite 12 hardfacing alloy to investigate if the surface structure and properties could be improved. More specifically the dry sliding wear performance of PTA and EBSM’ed hardfacings have been focused in the scope of this study. To the best of the authors’ knowledge, this approach, i.e. use of EBSM as a post deposition treatment of Stellite 12 hardfacings, has not been reported in open literature.
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Xiong, Jiankun, Fuheng Nie, Haiyan Zhao, Liangliang Zheng, Jun Luo, Lin Yang, and Zhongbo Wen. "Microstructure Evolution and Failure Behavior of Stellite 6 Coating on Steel after Long-Time Service." Coatings 9, no. 9 (August 22, 2019): 532. http://dx.doi.org/10.3390/coatings9090532.
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The microstructure evolution, elements diffusion and fracture behavior of the Stellite 6 weld overlay, deposited on 10Cr9Mo1VNbN (F91) steel by the tungsten inert gas (TIG) cladding process, were investigated after long-time service. Obvious diffusion of Fe occurred from the steel and fusion zone to the Stellite overlay, resulting in the microstructure evolution and hardness increase in the coating, where hard Co–Fe phases, σ phases (Fe–Cr metallic compounds) and Cr-rich carbides (Cr18.93Fe4.07C6) were formed. Besides, the width of the light zone, combined with the fusion zone and diffusion zone, increased significantly to a maximum value of 2.5 mm. The fracture of the Stellite coating samples mainly occurred in the light zone, which was caused by the formation and growth of circumferential crack and radial crack under high temperature and pressure conditions. Moreover, the micro-hardness values in the light zone increased to the maximum (470–680 HV) due to the formation and growth of brittle Co–Fe phases. The formation of these cracks might be caused by formed brittle phases and changes of micro-hardness during service.
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Batkhuu, P., G. Omoontsoo, B. Lygdenov, and A. Guriev. "Laser processing of high chromium white iron." Journal of Physics: Conference Series 2131, no. 5 (December 1, 2021): 052028. http://dx.doi.org/10.1088/1742-6596/2131/5/052028.
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Abstract Mechanical properties, such as wear-resistance and hardness, of laser welded and cladded high chromium white iron were investigated. The study involves the laser welding, cladding, and laser surface melt treatment by 3-kW Nd:YAG continuous wave high power laser. The laser welding of 2-mm thick high chromium white iron samples was laser welded in two combinations: iron-to-iron and iron-to-steel. Strong metallurgical bonding was witnessed between not only the iron samples but also iron and steel samples by laser welding. Three types of powder materials were used to laser clad the samples: metal-ceramic (compositionally close to INCO-702), stellite-21, and stellite-1 in order to estimate mechanical property changes and process ability of high chromium white iron. Even though the microstructure of metal-ceramic coating shows worse than stellite powder coatings it has more hardness and wear resistant property which were comparable to base iron. Hardness of metal-ceramic coating was slightly lower than base iron, yet the wear resistance was increased twofold.
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Smolina, Irina, and Karol Kobiela. "Characterization of Wear and Corrosion Resistance of Stellite 6 Laser Surfaced Alloyed (LSA) with Rhenium." Coatings 11, no. 3 (March 3, 2021): 292. http://dx.doi.org/10.3390/coatings11030292.
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This paper presents the method of preparation and study results of the Stellite 6 laser surface alloyed (LSA) with rhenium using na LDF diode laser (4000 W). During this process, a rhenium powder was introduced onto the surface of the Co-based alloy. The possibility of improving wear and corrosion resistance properties is interesting and worth investigating. The selected process parameters: the laser power of 900 W, powder feed rate in the range 1.92–3.83 g/min, and necessarily preheating of the substrate up to 200 °C—allowing to obtain the LSA layers on the Stellite 6 substrate. Depending on the process parameters, it is possible to modify the substrate’s surface layer in terms of rhenium concentration and geometrical characteristics of the laser tracks. It was found that undissolved particles of rhenium in laser-alloyed layers have a non-significant effect on their hardness and abrasion resistance. The laser surface-alloyed corrosion potential is better than the corrosion potential of the Stellite 6 substrate, including reducing resistance to pitting corrosion with a high ability to repassivation.
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Pfohl, C., and K. T. Rie. "Plasma duplex treatment of stellite." Surface and Coatings Technology 142-144 (July 2001): 1116–20. http://dx.doi.org/10.1016/s0257-8972(01)01224-5.
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Kim, Y. S., J. R. Park, E. Menthe, and K. T. Rie. "Plasma diffusion treatment of stellite." Surface and Coatings Technology 74-75 (September 1995): 425–30. http://dx.doi.org/10.1016/0257-8972(95)08341-3.
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Benghersallah, M., L. Boulanouar, G. Le Coz, A. Devillez, and D. Dudzinski. "Machinability of Stellite 6 hardfacing." EPJ Web of Conferences 6 (2010): 02001. http://dx.doi.org/10.1051/epjconf/20100602001.
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Shults, Phillip, Alphina Ho, Estelle M. Martin, Bethany L. McGregor, and Edward L. Vargo. "Genetic Diversity of Culicoides stellifer (Diptera: Ceratopogonidae) in the Southeastern United States Compared With Sequences From Ontario, Canada." Journal of Medical Entomology 57, no. 4 (February 26, 2020): 1324–27. http://dx.doi.org/10.1093/jme/tjaa025.
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Abstract Much of the bluetongue (BT) and epizootic hemorrhagic disease (EHD) research in North America focuses on white-tail deer and Culicoides sonorensis (Wirth & Jones) (Diptera: Ceratopogonidae), though several other biting midge species have been suggested as vectors. Culicoides stellifer (Coquillett) has been associated with hosts susceptible to hemorrhagic disease (HD), and more recently, specimens from Florida have tested positive for EHD and BT viral RNA. If C. stellifer is acting as a vector, this could have an impact on the distribution of HD in North America. To determine if gene flow is occurring across the range of C. stellifer within the southeast United States, a mitochondrial haplotype analysis was performed using the COI gene. Our haplotype network showed no population structure in C. stellifer from Florida, Texas, and South Carolina, as the overall genetic divergence between these sites was equal to the genetic divergence within each. We also compared these haplotypes to published sequences of C. stellifer collected in Ontario, Canada. Surprisingly, the genetic diversity of the flies from Ontario was two times greater than what was observed between the southeast U.S. collection sites. This considerable divergence could be evidence of a cryptic species. A better understanding of the connectivity between C. stellifer populations across all of North America will give insight into the distribution of HD. Our results show that gene flow is occurring between sites in the southeastern United States and potentially throughout the eastern distribution of the species.
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Yao, Jun, Bo Xin, Yadong Gong, and Guang Cheng. "Effect of Initial Temperature on the Microstructure and Properties of Stellite-6/Inconel 718 Functional Gradient Materials Formed by Laser Metal Deposition." Materials 14, no. 13 (June 28, 2021): 3609. http://dx.doi.org/10.3390/ma14133609.
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Stelite-6/Inconel 718 functionally gradient materials (FGM) is a heat-resisting functional gradient material with excellent strength performance under ultra-high temperatures (650–1100 °C) and, thus, has potential application in aeronautic and aerospace engineering such as engine turbine blade. To investigate the effect of initial temperature on the microstructure and properties of laser metal deposition (LMD) functional gradient material (FGM), this paper uses the LMD technique to form Stelite-6/Inconel 718 FGM at two different initial temperatures: room temperature and preheating (300 °C). Analysis of the internal residual stress distribution, elemental distribution, microstructure, tensile properties, and microhardness of 100% Stelite-6 to 100% Inconel 718 FGM formed at different initial temperatures in a 10% gradient. The experimental results prove that the high initial temperature effectively improves the uneven distribution of internal residual stresses. Preheating slows down the solidification time of the melt pool and facilitates the escape of gases and the homogeneous diffusion of elements in the melt pool. In addition, preheating reduces the bonding area between the gradient layers, enhancing the metallurgical bonding properties between the layers and improving the tensile properties. Compared with Stellite-6/Inconel 718 FGM formed at room temperature, the mean yield strength, mean tensile strength, and mean elongation of Stellite-6/Inconel 718 FGM formed at 300 °C are increased by 65.1 Mpa, 97 MPa, and 5.2%. However, the high initial temperature will affect the hardness of the material. The average hardness of Stellite-6/Inconel 718 FGM formed at 300 °C is 26.9 HV (Vickers hardness) lower than that of Stellite-6/Inconel 718 FGM formed at 20 °C.
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Koutsomichalis, Angelos, Michalis Vardavoulias, Antonios Lontos, and Nikolaos Vaxevanidis. "Tensile and bend behaviour of nanostructured HVOF and flame sprayed stellite coatings." MATEC Web of Conferences 188 (2018): 04015. http://dx.doi.org/10.1051/matecconf/201818804015.
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Stellite 6 powder (CoCrSiW) was deposited using flame spray (FS) and high velocity oxygen fuel (HVOF) techniques on steel substrates. The microstructure of stellite coatings produced with these deposition techniques displayed a rather similar morphology consisting of cobalt-rich dendrites surrounded by hard (Cr3C7) carbide particles. The stellite (both FS and HVOF) coating was found to reduce the tensile strength of the steel. The failure of the coated steel specimens initiated by cracking on the coating surface, transverse propagation of the cracks towards the coating - substrate interface and diversion along the interface leading to local delamination and breakage. During the bend tests cracks developed along the coating and the main failure in the coating occurred due to the tensile-shear deformation, particularly in the coating-substrate material interface. The coating thickness does not appear to affect the bending strength. During bending the number of surface cracks per unit length decreased with increasing coating thickness. Stereoscopic analysis showed that the thicker the coating the deeper the surface cracks. When the critical stress for crack propagation reached defect sites at the substratecoating interface, the entire coating failed and peeled off from the substrate.
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Chun, Eun-Joon. "Nanostructuring Behavior of NiCrBSi and CoCrWC Thermal Spray Coatings Formed by Temperature-Controlled Laser Heat Treatment." Korean Journal of Metals and Materials 58, no. 4 (April 5, 2020): 247–56. http://dx.doi.org/10.3365/kjmm.2020.58.4.247.
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.For surface hardening of a continuous casting mold component, a thermal spray coating of NiCrBSi (Metco-16C) and CoCrWC (Stellite-1) was performed followed by laser heat treatment of the coatings. To support selective modification of the thermal spray coating, a metallurgically determined surface temperature was maintained during the laser heat treatment, by real-time control of the laser power. In other words, nonhomogeneities in the macrosegregation of certain alloying elements, and voids in the as-sprayed state, could be improved. The main microstructural features of the Metco-16C coating laser-heat-treated at 1423 K were nanosized (100–150 nm) Cr5B3, M7C3, and M23C6 precipitates with a lamellar structure of Ni (FCC) and Ni3Si as the matrix phase. Those of the laser heat-treated Stellite- 1 coating at 1473 K were fine (30–250 nm) precipitates of WC, M7C3, and M23C6 based on a Co (FCC) matrix. The results show that laser heat treatment at 1423 K increased the hardness of the Mecto-16C coating to 1115 HV from the as-sprayed state (754 HV), while treatment at 1473 K increased the hardness of the Stellite-1 coating from 680 HV to 860 HV.
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SU, MOLIN, JIANING LI, XUEGANG WANG, and ZHIYUAN LIU. "AMORPHOUS/NANOCRYSTALLIZATION OF TiN-TiB2 REINFORCED LASER CLAD COMPOSITES." Surface Review and Letters 26, no. 09 (October 17, 2019): 1950057. http://dx.doi.org/10.1142/s0218625x19500574.
Full textAbstract:
Laser cladding (LC) of the Stellite6-BN-Cu-Y2O3 pre-placed powders on the Ti-6Al-4V alloy substrate formed the bulk TiN and needle-like Ti-B compounds reinforced composites, which improved the wear resistance of the substrate surface. The results showed that lots of the amorphous-nanocrystalline phases were produced in such composites; the proper content of Cu was used to refine microstructures, also a large number of the nanocrystals can be formed; the elements such as Co, Ni and Fe in Stellite6 favored the amorphous phase to be formed. The addition of Y2O3 improved the fluidity of the liquid metal, also retarding the growth of the dendrite, leading the fine microstructures to be formed, improving the property of the LC composites.
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Venkatesh, B., C. Anil Kumar Reddy, and Raghupathi. "Tribological Characteristics of Stellite Hard faced Layer on Mild Steel." IOP Conference Series: Materials Science and Engineering 1248, no. 1 (July 1, 2022): 012039. http://dx.doi.org/10.1088/1757-899x/1248/1/012039.
Full textAbstract:
Abstract Hardfacing is the oldest method of surface engineering for obtaining diverse characteristics and extending the life of materials. Even with typical use, all metal parts will corrode over time. As a result, they may lose their functioning, necessitating the purchase of a new part. This may occur more commonly in particular industrial applications, such as mining or agriculture. Hardfacing is a great solution for any metal element that is likely to wear over time. Hardfacing is typically done to worn rebuilt gear, but it can also be applied to new equipment to make it more wear-resistant. Hardfacing parts from older equipment can save you anywhere from 25 to 75 percent on replacement costs. Hardfacing can help extend the life of parts on latest equipment by up to 300 percent. Here chosen hardfacing technique as Tungsten Inert Gas Welding (TIGW) process to deposit stellite electrodes on base metal (i.e mild steel). The works is focus about deposit the hardfacing layers on mild steel specimens and perform comparative study of stellite -1 and stellite-12 hardfaced layers applied on mild steel specimens. The Objective of the project is to obtain better wear characteristics, hardness and better micro- structural properties of material.
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Durejko, Tomasz, and Magdalena Łazińska. "Characterization of Cobalt-Based Stellite 6 Alloy Coating Fabricated by Laser-Engineered Net Shaping (LENS)." Materials 14, no. 23 (December 4, 2021): 7442. http://dx.doi.org/10.3390/ma14237442.
Full textAbstract:
The results of microstructure and mechanical properties evaluation of a Stellite 6 (Co-6) alloy deposited on X22CrMoV12-1 substrate by the laser-engineered net shaping (LENSTM) technology are presented in this paper. The Stellite 6 alloy is widely used in industry due to its excellent wear resistance at elevated temperatures and corrosive environments. Specific properties of this alloy are useful in many applications, e.g., as protective coatings in steam turbine components. In this area, the main problems are related to the fabrication of coatings on complex-shaped parts, the low metallurgical quality of obtained coatings, and its insufficient adhesion to a substrate. The results of recently performed investigations proved that the LENS technology is one of the most effective manufacturing techniques of the Co-6 alloy coatings (especially deposited on complex-shaped turbine parts). The microstructural and phase analyses of obtained Stellite 6 coatings were carried out by light microscopy techniques and X-ray diffraction analysis. A chemical homogeneity of Co-6 based layers and a fluctuation of chemical composition in coating–substrate zone after the laser deposition were analyzed using an energy dispersive X-ray spectrometer coupled with scanning electron microscopy. The room temperature strength and ductility of the LENS processed layers were determined in static bending tests.