Improvement of wear resistance of wire drawing rolls with Cr–Ni–B–Si+WC thermal spraying powders (original) (raw)
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Effect of WC Concentration on Abrasive Wear Properties of the Thermally Sprayed WC-Ni Coatings
2013
In this work the effects of WC concentration on abrasive wear behavior by thermally sprayed WC coating was evaluated using three body abrasive wear tester. A different combination of WC and NI coatings were deposited on steel substrates by flame spraying using powder with different WC concentrations (0 %, 12.5 %, 25 %, and 50 %). Flame torch was used for heating and coating of process. Microstructure properties of coated samples were evaluated using optical microscope and wear testing, were performed on the samples.. Experimental results were compared to determine which coating shows the best quality in terms of the wear resistance. It was found that wear resistance is strongly depend on percentage of WC up to a certain level of mixing after that wear resistance will start decreasing.
Fraction on Wear Properties of Nicrbsi / WC Coatings
2012
To increase the lifetime of mechanical parts submitted to severe abrasive environments, a strategy is to reinforce their top surface by depositing a more resistant layer. This approach is particularly interesting for metallic parts exhibiting a poor wear resistance at high temperature. The incorporation of a dispersed ceramic phase within the reinforcing layer is known to increase dramatically the resistance and hardness of the top surface layer. In the present work, laser cladding was used to process thick metal/ceramic coatings on steel substrates. Metal matrix composite (MMC) coatings composed of Ni-based alloy containing hard tungsten carbide particles have been considered to improve the wear resistance of steel parts (S235 low carbon steel). The secondary phase amount and its particle size have been studied. In order to limit the formation of cracks during the layer cooling down, subsequent to laser cladding, preand postheating at 400 °C of the samples were performed.
Wear Performance of Thermally Sprayed NiCrBSi and NiCrBSi-WC Coatings Under Two Different Wear Modes
Journal of Materials and Environmental Sciences, 2017
NiCrBSi is a Ni-based alloy universally recognized for its superior mechanical properties, attributed to the presence of hard-dispersed carbides and borides, which is dependent on the deposition technique. Moreover, Metal Matrix Composites (MMC) materials will aim to combine the resilience of metals with high wear resistance specific of ceramics which made them innovative for a large wide of wear resistance applications. In this paper, thick NiCrBSi and NiCrBSi-WC coatings are made ontoS235JR mild steel substrates using an oxyacetylene flame-spraying torch (SuperJetEutalloy, Castolin Eutectic). Two different wear tests: sand/wheel wear test in dry conditions and the pin-on-disc wear test in continuous motion are used to investigate addition effects of WC reinforcing ceramic phase on the microstructure and wear resistance of the coatings layers. The results show that the presence of ceramic phase affects the wear resistance of the coating. For both wear tests, the metallic alloy coating has an improved wear resistance than the reinforced ones. WC reinforcement does not play the protective role of the matrix against wear but improve the hardness. Wear mechanism is mainly controlled by the scratching and by the pull out of WC particles because of their faceted shape.
Wear Characteristics of Ni-WC Powder Deposited by Using a Microwave Route on Mild Steel
International Journal of Surface Engineering and Interdisciplinary Materials Science, 2020
In the present research work, Ni-WC powder was deposited on mild steel using a microwave applicator. Deposited clad has a thickness of 0.5 mm and deposition time taken for coating was 15 minutes for each sample size. The developed layer on the substrate was analysed through several testing techniques include mechanical characterization by the Vickers hardness test and a wear test on the Pin-on disc apparatus according to ASTM-G99 standard. Furthermore, micro structural characterization was done by using scanning electron microscopy technique and it has shown proper bonding between powder and substrate. Coating showed excellent results in terms of hardness and wear resistance as compared to base material mils steel. The pullout, scoring and abrasion were the responsible wear mechanisms in the substrate and clad.
A study of the wear performance of TiN, CrN and WC/C coatings on different steel substrates
Wear, 2011
In this study, the performance of the coatings TiN, CrN and WC/C applied on steel substrates that were subjected to sliding wear was analyzed. These materials normally exhibit an efficient performance in applications such as coatings of cutting tools, stamping processes, forming and plastic injection tooling where the contact and sliding conditions are severe. Due to this fact, this research was conducted to characterize the materials in relation to the wear process. The sliding wear test was performed using a reciprocating wear test machine. All tests were conducted in dry conditions with a room temperature between 20 • C and 23 • C and 45% to 50% relative humidity. A sliding velocity of 0.08 m/s and 2 mm amplitude were used. The applied loads were 11.76 N (Po = 1.74 GPa) and 7.84 N (1.52 GPa), respectively. Optical microscopy and scanning electron microscopy (SEM) were used to observe and analyze the wear mechanisms. Additionally, the variation of the friction coefficient versus the number of cycles was obtained. This was used to determine with a higher precision the time (presented as number of cycles) where the coating presented the initial signs of wear damage. In addition, energy dispersive X-ray analysis (EDS) was performed to obtain the chemical composition of the materials and hardness tests on the wear tracks were also carried out. It was possible to know the wear life of these coatings and possible causes of life variations. The load was an important factor in the variation of the wear life results, although other factors such as surface roughness and coating thickness were also significant.
Surface & Coatings Technology, 2007
In present paper the influence of the tungsten carbide (WC) particle addition on the microstructure, microhardness and abrasive wear behaviour of flame sprayed Co-Cr-W-Ni-C (EWAC 1006) coatings deposited on low carbon steel substrate has been reported. Coatings were deposited by oxy-acetylene flame spraying process. Wear behaviour of coatings was evaluated using pin on flat wear system against SiC abrasive medium. It was observed that the addition of WC particle in a commercial Co-Cr-W-Ni-C powder coating increases microhardness and wear resistance. Wear behaviour of these coatings is governed by the material parameters such as microstructure, hardness of coating and test parameters (abrasive grit size and normal load). Addition of WC in a commercial powder coating increased wear resistance about 4-9 folds. WC modified powder coatings showed better wear resistance at high load. Heat treatment of the unmodified powder coatings improved abrasive wear resistance while that of modified powder coating deteriorated the wear resistance. SEM study showed that wear of coatings largely takes place by microgroove, crater formation and scoring. Electron probe micro analysis (E.P.M.A.) of unmodified and WC modified powder coating was carried out for composition and phase analysis.
Applications of Laser Cladded WC-Based Wear Resistant Coatings
Physics Procedia, 2011
Laser cladding is an additive process wherein a laser source is used to melt metal-based powder or wire on to a metal substrate. The technique is frequently used to produce wear resistant coatings consisting of a metal matrix and a ceramic strengthening phase. In this study mixtures of nickel based powders and various amounts of tungsten carbides have been used as feedstock for laser cladding on a range of steel substrates and for different applications. Crack-free low porosity coatings with a thickness of about 1 mm and carbide concentrations up to 50 vol% have been produced. The evaluation of the wear resistance of the different coatings is performed on lab scale or in the application itself.
Studies on remelting of tungsten carbide and rare earth modified nickel base alloy composite coating
Surface Engineering, 2012
The Ni base alloy (EWAC 1004EN) was used to develop coatings on the mild steel substrate by flame spraying process. The Ni base alloy powder was modified by adding tungsten carbide (10 and 20 wt-%) and CeO 2 to study their effects on the microstructure, microhardness and abrasive wear behaviour of unmodified and modified coatings. All the coatings were subjected to remelting using tungsten inert gas arc welding. The abrasive wear behaviour of all the coatings in different conditions was studied using different normal loads (5, 10, 15 and 20 N) against 120 and 600 grit size abrasive medium. Scanning electron microscopy analysis of the worn out surfaces was carried out to understand the wear mechanisms. It was observed that the remelting of the coatings increased the hardness of WC and CeO 2 modified flame sprayed coatings by ,35%, while the abrasive wear resistance increased by 1?5-to threefold.
Materials Processing and Interfaces, 2012
This paper describes effect of the lanthanum oxide (La 2 O 3 ) and remelting on microstructure; hardness and abrasive wear behavior of Ni-WC composite powder flame sprayed coatings. It was found that La 2 O 3 modification and remelting of flame sprayed Ni-base composite coating refined the microstructure and increased microhardness and resistance to abrasive wear. La 2 O 3 modification and remelting of the coating increased hardness by 1.2 to 1.3 folds. Abrasive wear behavior of unmodified and La 2 O 3 modified coating in as spayed and re-melted conditions were studied against at different normal loads (5, 10, 15 and 20N) and abrasive mediums of 120 and 600 grit sizes. La 2 O 3 modified composite coating in re-melted condition showed minimum wear rate irrespective of normal load and abrasive medium. Abrasive wear study results were supported by SEM analysis of worn out surfaces.