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Stellite

About: Stellite is a research topic. Over the lifetime, 1040 publications have been published within this topic receiving 13745 citations.


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Journal ArticleDOI
TL;DR: In this article, various types of MMC coatings were prepared by laser coating methods, which consisted of vanadium, tungsten, titanium and chromium carbide hard phases mixed with metallic tool steel M2, Stellite 21, NiCrBSi-alloy and Inconel 625.
Abstract: Laser coating (laser cladding) is a useful method to produce metal matrix composite (MMC) coatings. The selection of the metallic matrix can be done on the base of the intended application and environment, whereas the additional wear resistance improvement is provided by mixing various carbides with the metallic matrix. In the present work, various types of MMC coatings were prepared by laser coating methods. The coatings consisted of vanadium, tungsten, titanium and chromium carbide hard phases mixed with metallic tool steel M2, Stellite 21, NiCrBSi-alloy and Inconel 625. Different levels of carbide contents were used. The abrasion resistance of the MMC coatings has been tested using a rubber-wheel abrasion apparatus. The wear surfaces were examined and the microstructures of MMC coatings were analysed in order to determine microstructures and carbide dissolution. The best abrasion results were achieved by the correct choice of carbide for each matrix material.

194 citations

Journal ArticleDOI
TL;DR: In this article, the effect of power density and beam interaction time on the performance of laser cladding of the leading edge of a steam turbine blade in a 12Cr-Ni turbine is discussed microscopically.
Abstract: Water droplet erosion of leading edge of the blade in a steam turbine could impair its efficiency and lifetime. To overcome this problem, laser cladding of the leading edge with Co-based stellite powder is commonly used. This paper discusses microscopically the effect of power density and beam interaction time in such a cladding process. It is realized that the beam interaction time has a significant effect on solidification and microstructure development process. The results indicate that the dendrite structure shall be fine for short interaction time compared to the coarse structure for long interaction time. Macro- and micro- cross-section electron probe microanalysis (EPMA) and microhardness profile has been employed to characterize the cladding. The results are correlated with the clad quality. Microstructure, hardness and dilution are discussed as a function of the processing parameters. A few of the actual results of the laser cladding of stellite 6L on 12Cr–Ni turbine blades are presented. Since the dilution of the base material into the cladding is significantly low at short interaction times, the clad could retain significant strength after long-term exposure, a unique feature for the turbine industries. Such possible applications are illustrated as well.

173 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of Mo on the microstructures and wear resistance properties of the Stellite 6 hardfacing alloys were investigated using optical microscopy, scanning electron microscopy and electron probe microanalysis and X-ray diffraction.
Abstract: The Stellite 6 hardfacing alloys with different Mo contents have been deposited on AISI 1045-carbon steel using a Plasma Transferred Arc (PTA) welding machine. The effect of Mo on the microstructures and wear resistance properties of the Stellite 6 hardfacing alloys were investigated using optical microscopy, scanning electron microscopy, electron probe microanalysis and X-ray diffraction. With an increase in Mo contents, the M 23 C 6 and M 6 C type carbides were formed instead of Cr-rich M 7 C 3 and M 23 C 6 type carbides observed in the interdenritic region of the Mo-free Stellite 6 hardfacing alloy. The size of Cr-rich carbides in interdendritic region decreased, but that of M 6 C type carbide increased as well as the refinement of Co-rich dendrites. The volume fraction of Cr-rich carbides slightly increased, but that of M 6 C type carbide abruptly increased. This microstructural change was responsible for the improvement of the mechanical properties such as hardness and wear resistance of the Mo-modified Stellite 6 hardfacing alloy.

162 citations

Journal ArticleDOI
TL;DR: In this article, the relationship between the relevant laser cladding parameters (i.e., laser beam scanning speed, laser power and powder feeding rate) and the main geometrical characteristics of a single laser track (height, width, dilution, etc.) were examined.
Abstract: The objective of this work was to create Co-based coatings (compositionally close to Stellite 6) on compacted graphite and gray cast iron substrates with a high power laser (2 kW continuous Nd:YAG) cladding process. The relationships between the relevant laser cladding parameters (i.e. laser beam scanning speed, laser power and powder feeding rate) and the main geometrical characteristics of a single laser track (height, width, dilution, etc.) were examined. A gradual variation of a single processing parameter was used for an appropriate experimental analysis and statistical correlations study between main processing parameters and geometrical characteristics of an individual laser track. These relations lead to the design of a laser cladding processing map that can be used as a guideline for the selection and further tuning of proper processing parameters for laser cladding of extensive layer. The coatings with thickness from 1.0 to 3.3 mm were created on flat substrates without cracks and other major defects. The microstructural features of these coatings were studied using optical microscopy, scanning electron microscopy (Philips XL30 FEG), EDS (EDAX) and XRD. Mechanical properties were determined using microhardness measurement, scratch test (CSM Revetest) analysis at room temperature and using the tribotesting (CSM HT Tribometer) at room and elevated (up to 525 °C) temperatures.

157 citations

Journal ArticleDOI
TL;DR: In this article, the method of preparation and study results of metal matrix composite coatings (MMC coating) in the system of Stellite-6 and tungsten carbides were investigated.
Abstract: The paper presents the method of preparation and study results of metal matrix composite coatings (MMC coating) in the system of Stellite-6 and tungsten carbides. Changes in microstructure, corrosion resistance, microhardness, phase and chemical composition as well as surface conditions were investigated. Stellite-6/WC MMC coatings were prepared by laser cladding technology using a 1 kW continuous wave Yb:YAG disk laser with a powder feeding system. Two different powder mixtures containing 30% and 60% of WC and three different values of laser beam power were used. It was found that increasing WC values caused an increase in microhardness on the cross-section of the produced coating in comparison to the substrate. Depending on the laser beam power, the coatings produced with 30% WC achieved microhardness in the range from about 350 HV0.05 (700 W) to about 680 HV0.05 (550 W). Twice as large amount of WC particles in the powder mixture resulted in increase of microhardness from about 700 HV0.05 (700 W) to about 1500 HV0.05 (550 W). In the coating M7C3, M6C and M23C6 carbides were identified by an X-ray diffraction method. Special attention was given to bondings between carbide particles and metal matrix, which had a characteristic microstructure. A reduction of corrosion resistance with increasing WC content in coating was also discovered.

148 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202345
202284
202152
202055
201967
201836