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Shiyao Qu - One of the best experts on this subject based on the ideXlab platform.
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microstructure and wear properties of the fe ti v mo c Hardfacing alloy
Wear, 2008Co-Authors: Xinhong Wang, Shiyao QuAbstract:Abstract In this study, different Hardfacing layers were produced by shield manual arc welding (SMAW) process in which a bare electrode of H08A was coated with fluxes, to which different measures of ferrotitanium (Fe–Ti), ferrovanadium (Fe–V), ferromolybdenum (Fe–Mo) and graphite had been added. The influence of added alloy elements on the microstructure and wear properties of the Fe-based Hardfacing layers was investigated. The results showed that complex carbides of TiC–VC–Mo2C were synthesized via metallurgic reaction during welding. Carbides are uniformly dispersed in the matrix. The addition of graphite and ferromolybdenum can enhance macro-hardness and wear resistance of the Hardfacing layer significantly, but increase the crack sensitivity of the Hardfacing layer. With the increasing of the additions of Fe–Ti and Fe–V, the macro-hardness and wear resistance of the Hardfacing layers increased. A good resistance to cracking and wear resistance of the Hardfacing layer could be obtained, when the amounts of graphite, Fe–Ti, Fe–V and Fe–Mo were controlled within a range of 8–10%, 12–15%, 10–12% and 2–4%, respectively. The wear resistance of the deposited layer surfaced by Fe–Ti–V–Mo–C Hardfacing alloy possesses a higher wear resistance and less friction coefficient than that of the deposited layer surfaced by EDRCrMoWV-A3-15 Hardfacing alloy.
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Microstructure and wear properties of the Fe–Ti–V–Mo–C Hardfacing alloy
Wear, 2008Co-Authors: Xinhong Wang, Shiyao QuAbstract:Abstract In this study, different Hardfacing layers were produced by shield manual arc welding (SMAW) process in which a bare electrode of H08A was coated with fluxes, to which different measures of ferrotitanium (Fe–Ti), ferrovanadium (Fe–V), ferromolybdenum (Fe–Mo) and graphite had been added. The influence of added alloy elements on the microstructure and wear properties of the Fe-based Hardfacing layers was investigated. The results showed that complex carbides of TiC–VC–Mo2C were synthesized via metallurgic reaction during welding. Carbides are uniformly dispersed in the matrix. The addition of graphite and ferromolybdenum can enhance macro-hardness and wear resistance of the Hardfacing layer significantly, but increase the crack sensitivity of the Hardfacing layer. With the increasing of the additions of Fe–Ti and Fe–V, the macro-hardness and wear resistance of the Hardfacing layers increased. A good resistance to cracking and wear resistance of the Hardfacing layer could be obtained, when the amounts of graphite, Fe–Ti, Fe–V and Fe–Mo were controlled within a range of 8–10%, 12–15%, 10–12% and 2–4%, respectively. The wear resistance of the deposited layer surfaced by Fe–Ti–V–Mo–C Hardfacing alloy possesses a higher wear resistance and less friction coefficient than that of the deposited layer surfaced by EDRCrMoWV-A3-15 Hardfacing alloy.
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effect of molybdenum on the microstructure and wear resistance of fe based Hardfacing coatings
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: X.h. Wang, Shiyao QuAbstract:Abstract Fe-based Hardfacing alloys containing molybdenum compound have been deposited on AISI 1020 steel substrates by shield manual arc welding (SMAW) process. The effect of Mo on the microstructure and wear resistance of the Fe-based Hardfacing alloys were investigated by means of X-ray diffraction, optical microscopy, scanning electron microscopy (SEM) and electron probe microanalysis, as well as wear test. The results indicated that cuboidal and rod-type complex carbides were synthesized in the lath martensite matrix. The fraction of carbides in Hardfacing layer increased with an increasing of Mo content. The Hardfacing layer with good cracking resistance and wear resistance could be obtained when the amounts of Fe–Mo was controlled within a range of 3–4 wt.%. The improvement of hardness and wear resistance of the Hardfacing layers attributed to the formation of Mo 2 C carbide and the solution strengthening of Mo.
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microstructure of the fe based Hardfacing layers reinforced by tic vc mo2c particles
Surface & Coatings Technology, 2008Co-Authors: Xinhong Wang, Shiyao QuAbstract:Abstract In this study, the Hardfacing alloys with different measures of ferrotitanium (Fe–Ti), ferrovanadium (Fe–V), ferromolybdenum (Fe–Mo) and graphite were deposited on AISI 1020 steel substrates by shielded manual arc welding (SMAW). Fe-based Hardfacing layers reinforced by carbide particles were produced. The thermodynamic analysis for carbide and effect of the carbide forming elements on the properties of Hardfacing layers were also discussed. The experimental results showed that TiC-VC-Mo 2 C carbides could be synthesized by metallurgic reaction during SMAW process. Carbides with particle sizes in the range 1–3 μm are uniformly dispersed in the matrix. The Hardfacing layer with good cracking resistance and high hardness could be obtained when the amounts of graphite, Fe–Ti, Fe–V and Fe–Mo were controlled within a range of 8–10%, 12–15%, 10–12% and 2–4%, respectively.
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Microstructure and properties of the TiC/Fe-based alloy Hardfacing layers
Journal of Materials Science, 2005Co-Authors: Xinhong Wang, Shiyao Qu, S.l. SongAbstract:TiC/Fe-based alloy Hardfacing layers were obtained by shielded metal arc welding (SMAW), in which H08A bare electrode was coated with a powder mixture of ferrotitanium, rutile, graphite, calcium carbonate and calcium fluoride. TiC particles are produced by direct metallurgical reaction between ferrotitanium and graphite during welding. The particles of TiC with cubic shape are distributed evenly in the Fe-rich matrix in the Hardfacing layers, the particle size is about 3–5 μ m. The microstructure and mechanical properties of the Hardfacing layers are markedly affected by the amounted of the ferrotitanium and graphite in the coating of the electrode. The wear properties of the Hardfacing layers are superior to the substrate AISI 1045 steel. The coefficient of friction data of the Hardfacing layers do not show significant fluctuations.
Yulin Yang - One of the best experts on this subject based on the ideXlab platform.
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Effects of Vanadium Addition on Microstructure and Tribological Performance of Bainite Hardfacing Coatings
Journal of Materials Engineering and Performance, 2015Co-Authors: Jigang Chen, Yulin Yang, Xiaolei Xing, Yajun Wang, Yefei Zhou, Qingxiang YangAbstract:New Hardfacing coatings with different vanadium (V) additions were prepared by surfacing technology. The microstructures of the Hardfacing coatings were analyzed by field emission scanning electron microscope equipped with energy dispersive X-ray spectrometry and examined by transmission electron microscope. The hardness and wear resistances of the Hardfacing coatings were measured. Worn debris were collected at the end of wear test and analyzed. The precipitation temperature of the phases in the Hardfacing coatings and the mass fraction of MC carbide were calculated by Jmatpro software. The experimental results show that, the Hardfacing coating mainly consists of granular bainite. No significant change in the size of linear martensite-austenite (M-A) islands is observed with the increase of V addition, while the size of massive M-A islands is decreased. The wear resistance of the Hardfacing coating reaches a maximum level with V content of 0.14 wt.%. The calculated results show that, the mass fraction of MC carbide is increased with the increase of V content. Based on calculation following two-dimensional mismatch theory, MC carbide is a heterogeneous nucleus of the ferrite resulting refined ferrite in the Hardfacing coating.
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microstructure and wear resistance of the hypereutectic fe cr c alloy Hardfacing metals with different la2o3 additives
Applied Surface Science, 2014Co-Authors: Jian Yang, Yulin Yang, Jianjun Tian, Qingxiang YangAbstract:Abstract Hardfacing (harden-surface-welding) metal of the hypereutectic Fe–Cr–C alloy with different La2O3 additives was developed. The microstructure of the Hardfacing metal was observed by optical microscopy. The phase structure was determined by X-ray diffraction. The hardness and wear resistance of the Hardfacing metal were measured by hardness tester and dry sand rubber wheel abrasive tester, respectively. The worn surface morphology was observed by field emission scanning electron microscope equipped with energy dispersive X-ray spectrometry. The solidification curve of the Hardfacing metal and the relationship between the content of each phase and the temperature were calculated by thermodynamics software Thermo-Calc and Jmatpro, respectively. The results indicate that, with the increase of the La2O3 additives, the dimension of the primary M7C3 carbide in the hypereutectic Fe–Cr–C alloy Hardfacing metal decreases gradually. When the La2O3 additive is 0.78 wt.%, it reaches minimum, which is 11.37 μm. The amount of M7C3 carbide (including the primary carbide and the eutectic carbide) decreases firstly then increases. The hardness of the Hardfacing metal increases smally, while the wear resistance of it increases firstly then decreases and reaches the most excellent when the La2O3 additive is 0.78 wt.%. The formation temperature of M7C3 carbide is higher than that of austenite in the hypereutectic Fe–Cr–C alloy Hardfacing metal. Austenite precipitated in the liquid phase can improve the precipitation rate of M7C3 carbide in a certain extent. As the temperature of the molten pool drops from 870 °C to 840 °C, γ-Fe transforms into α-Fe completely, so a large number of C atoms precipitate, which promotes the growth of the M7C3 carbide in short period.
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effects of vanadium additive on structure property and tribological performance of high chromium cast iron Hardfacing metal
Surface & Coatings Technology, 2011Co-Authors: Xiaowen Qi, Qingxiang Yang, Yulin YangAbstract:Abstract Hard and wear-resistance layer of high chromium cast iron (HCCI) with vanadium additive was prepared by surfacing technology. Using DSC the phase transition temperature curve of surfacing alloy layer was examined. The content of carbide in Hardfacing layer was further determined through microstructure analysis. Meanwhile, iron–carbon equilibrium phase diagram of Hardfacing layer was calculated. In addition, the wear-resistance of Hardfacing layer was carried out. The results show that the carbide precipitated from Hardfacing layer is the type of M7C3. Primary, eutectic and secondary carbides are approximately hexagonal structure, long rods and fine spherical, respectively. However, the secondary carbide VC is precipitated from the Hardfacing layer when vanadium additive was added into flux cored wire. As the content of vanadium additive increases in the flux-cored wire, the size of primary carbide significantly reduces and the amount of eutectic and secondary carbides gradually increase. Therefore, the improvement of wear-resistance of surfacing layer was mainly due to the vanadium additive in flux-cored wire.
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Effects of RE oxide on the microstructure of Hardfacing metal of the large gear
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Da Li, Yulin Yang, Jiazhen Zhang, Qingxiang YangAbstract:The Rare Earth (RE) oxide was added into the electrode coating for Hardfacing large gear and the microstructures of the Hardfacing specimens with and without RE oxide were observed by using optical microscopy (OM). Meanwhile, the matrix phase of the Hardfacing metals was determined by using X-ray diffraction (XRD) and the fractographs as well as inclusions were observed and analyzed by using scanning electron microscopy (SEM) with energy dispersive spectrum (EDS). The results show that, the microstructure of the Hardfacing metal is mainly composed of the fine acicular ferrite, and the fracture surface is uniform and fine dimple exists on the fractograph of the specimen with RE oxide. The inclusions become spherical ones, which are distributed in Hardfacing metal dispersively. However, the microstructure of the Hardfacing metal is composed of coarse acicular ferrite and pearlite, and the fractograph is composed with dimple and quasi-cleavage in the specimen without RE oxide.
You Wang - One of the best experts on this subject based on the ideXlab platform.
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study of work function and dry sliding wear behavior of fe based Hardfacing alloys with and without nano rare earth oxides
Journal of Alloys and Compounds, 2017Co-Authors: You Wang, Xuewei LiAbstract:Abstract In this paper, work function and dry sliding wear behavior of the Hardfacing alloys with different content of nano rare earth oxides (REOs) were studied. The microstructural changes of the Hardfacing alloys with and without nano REOs were observed. The integral work function of Hardfacing alloys was measured by Scanning Kelvin Probe. The individual work function of the constituent phases was indirectly measured and compared by Atomic Force Microscope. Pin-on-disc wear testing machine was used to conduct dry sliding wear tests. The results showed that nano REOs changed the volume fractions of primary carbide, eutectic carbide and the matrix. Nano REOs increased the integral work function of Hardfacing alloys by increasing the volume fraction of primary carbide with high work function. The work functions of primary carbide and eutectic carbide were similar, which were higher than that of the matrix. Nano REOs improved the wear resistance of Hardfacing alloys. The variation trends of friction coefficient and integral work function with the content of nano REOs were reversed. The variation trends of wear rate and integral work function with the content of nano REOs were also reversed. The Hardfacing alloy having higher integral work function had better wear resistance.
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the effect of nano additives containing rare earth oxides on sliding wear behavior of high chromium cast iron Hardfacing alloys
Tribology International, 2016Co-Authors: You Wang, Dongxia ZhenAbstract:Abstract High chromium cast iron (HCCI) Hardfacing alloys with nano-additives were prepared. The effects of nano-additives on the microstructure of Hardfacing alloys were studied by a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). A Rockwell hardness tester was used to measure the hardness represented by Rockwell C-scale hardness (HRC). The friction and wear behavior of the Hardfacing alloys with different nano-additives was investigated using ball-on-disc sliding wear tests. The experimental results showed that the volume fraction of primary carbide increased and then decreased with the increase of nano-additives. The volume fraction of primary carbide in the Hardfacing alloy with 0.288 wt% nano-additives increased by 27% than that of the Hardfacing alloy without nano-additives. The XRD results showed that Hardfacing alloys were composed of M 7 C 3 (M mainly represented Fe and Cr), martensite and retained austenite. The hardness of the Hardfacing alloy without nano-additives was 61.5HRC. The hardness of the Hardfacing alloy with 0.288 wt% nano-additives reached 64.5HRC. The wear rate of the Hardfacing alloy with 0.288 wt% nano-additives decreased by 21.2% than that of the Hardfacing alloy without nano-additives. The main wear mechanism of the Hardfacing alloys with nano-additives was abrasion wear accompanied by severe adhesion wear.
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Effect of nano-additives on microstructure, mechanical properties and wear behaviour of FeCrB Hardfacing alloy
Applied Surface Science, 2015Co-Authors: Pengpeng Lu, You WangAbstract:Abstract Fe⿿Cr⿿B Hardfacing alloys with different nano-additives content were investigated. The effects of nano-additives on the microstructures of Hardfacing alloy were studied by using optical microscope, scanning electron microscope, X-ray diffractometer. The hardness and the fracture toughness of Hardfacing alloys were measured, respectively. The sliding wear tests were carried out using a ball-on-disc tribometer. The experimental results showed that primary carbide of Hardfacing alloys was refined and its distribution became uniform with content of nano-additives increased. The Hardfacing alloys are composed of Cr 7 C 3 , Fe 7 C 3 , α-Fe and Fe 2 B according to the results of X-ray diffraction. The hardness of Hardfacing alloys increased linearly with the increase of nano-additives. The hardness of the Hardfacing alloy with 1.5 wt.% nano-additives increased 54.8% than that of the Hardfacing alloy without nano-additives and reached to 1011HV. The K IC of the Hardfacing alloy with 0.65 wt.% nano-additives was 15.4 MPam 1/2 , which reached a maximum. The value increased 57.1% than that of the Hardfacing alloy without nano-additives. The wear rates of the Hardfacing layer with 0.65 wt.% and 1.0 wt.% nano-additives decreased about 88% than that of the Hardfacing layer without nano-additives. The main wear mechanism was adhesion wear.
Qingxiang Yang - One of the best experts on this subject based on the ideXlab platform.
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Effects of Vanadium Addition on Microstructure and Tribological Performance of Bainite Hardfacing Coatings
Journal of Materials Engineering and Performance, 2015Co-Authors: Jigang Chen, Yulin Yang, Xiaolei Xing, Yajun Wang, Yefei Zhou, Qingxiang YangAbstract:New Hardfacing coatings with different vanadium (V) additions were prepared by surfacing technology. The microstructures of the Hardfacing coatings were analyzed by field emission scanning electron microscope equipped with energy dispersive X-ray spectrometry and examined by transmission electron microscope. The hardness and wear resistances of the Hardfacing coatings were measured. Worn debris were collected at the end of wear test and analyzed. The precipitation temperature of the phases in the Hardfacing coatings and the mass fraction of MC carbide were calculated by Jmatpro software. The experimental results show that, the Hardfacing coating mainly consists of granular bainite. No significant change in the size of linear martensite-austenite (M-A) islands is observed with the increase of V addition, while the size of massive M-A islands is decreased. The wear resistance of the Hardfacing coating reaches a maximum level with V content of 0.14 wt.%. The calculated results show that, the mass fraction of MC carbide is increased with the increase of V content. Based on calculation following two-dimensional mismatch theory, MC carbide is a heterogeneous nucleus of the ferrite resulting refined ferrite in the Hardfacing coating.
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microstructure and wear resistance of the hypereutectic fe cr c alloy Hardfacing metals with different la2o3 additives
Applied Surface Science, 2014Co-Authors: Jian Yang, Yulin Yang, Jianjun Tian, Qingxiang YangAbstract:Abstract Hardfacing (harden-surface-welding) metal of the hypereutectic Fe–Cr–C alloy with different La2O3 additives was developed. The microstructure of the Hardfacing metal was observed by optical microscopy. The phase structure was determined by X-ray diffraction. The hardness and wear resistance of the Hardfacing metal were measured by hardness tester and dry sand rubber wheel abrasive tester, respectively. The worn surface morphology was observed by field emission scanning electron microscope equipped with energy dispersive X-ray spectrometry. The solidification curve of the Hardfacing metal and the relationship between the content of each phase and the temperature were calculated by thermodynamics software Thermo-Calc and Jmatpro, respectively. The results indicate that, with the increase of the La2O3 additives, the dimension of the primary M7C3 carbide in the hypereutectic Fe–Cr–C alloy Hardfacing metal decreases gradually. When the La2O3 additive is 0.78 wt.%, it reaches minimum, which is 11.37 μm. The amount of M7C3 carbide (including the primary carbide and the eutectic carbide) decreases firstly then increases. The hardness of the Hardfacing metal increases smally, while the wear resistance of it increases firstly then decreases and reaches the most excellent when the La2O3 additive is 0.78 wt.%. The formation temperature of M7C3 carbide is higher than that of austenite in the hypereutectic Fe–Cr–C alloy Hardfacing metal. Austenite precipitated in the liquid phase can improve the precipitation rate of M7C3 carbide in a certain extent. As the temperature of the molten pool drops from 870 °C to 840 °C, γ-Fe transforms into α-Fe completely, so a large number of C atoms precipitate, which promotes the growth of the M7C3 carbide in short period.
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effects of vanadium additive on structure property and tribological performance of high chromium cast iron Hardfacing metal
Surface & Coatings Technology, 2011Co-Authors: Xiaowen Qi, Qingxiang Yang, Yulin YangAbstract:Abstract Hard and wear-resistance layer of high chromium cast iron (HCCI) with vanadium additive was prepared by surfacing technology. Using DSC the phase transition temperature curve of surfacing alloy layer was examined. The content of carbide in Hardfacing layer was further determined through microstructure analysis. Meanwhile, iron–carbon equilibrium phase diagram of Hardfacing layer was calculated. In addition, the wear-resistance of Hardfacing layer was carried out. The results show that the carbide precipitated from Hardfacing layer is the type of M7C3. Primary, eutectic and secondary carbides are approximately hexagonal structure, long rods and fine spherical, respectively. However, the secondary carbide VC is precipitated from the Hardfacing layer when vanadium additive was added into flux cored wire. As the content of vanadium additive increases in the flux-cored wire, the size of primary carbide significantly reduces and the amount of eutectic and secondary carbides gradually increase. Therefore, the improvement of wear-resistance of surfacing layer was mainly due to the vanadium additive in flux-cored wire.
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effect of rare earth oxides on the morphology of carbides in Hardfacing metal of high chromium cast iron
Journal of Rare Earths, 2011Co-Authors: Li Da, Bo Liao, Qingxiang YangAbstract:Abstract The flux cored wires with different amounts of rare earth (RE) oxides additions for Hardfacing (harden-face-welding) the workpieces of high chromium cast iron were studied in this work. The morphology of carbides in Hardfacing metal was observed, and the type of the carbides was determined by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). Based on the data of effect of RE on carbides morphology, the refined reason for carbide by RE oxide was discussed with the misfit theory. The results showed that, the microstructure of Hardfacing metal was composed of martensite, residual austenite and M 7 C 3 carbides. With the increasing amount of RE oxide additions, the volume fraction and roundness of the carbides were increased, however, the area and perimeter of carbides were decreased. It indicated that carbides in Hardfacing metal could be refined and spheroidized by adding RE oxides in flux cored wires.
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Effects of RE oxide on the microstructure of Hardfacing metal of the large gear
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Da Li, Yulin Yang, Jiazhen Zhang, Qingxiang YangAbstract:The Rare Earth (RE) oxide was added into the electrode coating for Hardfacing large gear and the microstructures of the Hardfacing specimens with and without RE oxide were observed by using optical microscopy (OM). Meanwhile, the matrix phase of the Hardfacing metals was determined by using X-ray diffraction (XRD) and the fractographs as well as inclusions were observed and analyzed by using scanning electron microscopy (SEM) with energy dispersive spectrum (EDS). The results show that, the microstructure of the Hardfacing metal is mainly composed of the fine acicular ferrite, and the fracture surface is uniform and fine dimple exists on the fractograph of the specimen with RE oxide. The inclusions become spherical ones, which are distributed in Hardfacing metal dispersively. However, the microstructure of the Hardfacing metal is composed of coarse acicular ferrite and pearlite, and the fractograph is composed with dimple and quasi-cleavage in the specimen without RE oxide.
Ke Yang - One of the best experts on this subject based on the ideXlab platform.
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Effect of Titanium Content on Microstructure and Wear Resistance of Hardfacing Alloy
Journal of Wuhan University of Technology-materials Science Edition, 2018Co-Authors: Ke Yang, Yong Feng JiangAbstract:The Hardfacing alloys with different concentrations of titanium were deposited on carbon steel substrates by shielded metal arc welding, and the effect of titanium content on the microstructure characteristics of the Hardfacing alloys was investigated. The wear resistance test of the Hardfacing alloys was carried out by using a slurry rubber wheel abrasion test machine, and the wear behaviour was also studied. The results indicate that the addition of titanium can effectively promote the precipitation of the complex carbides of Nb and Ti due to the prior precipitation of titanium carbide which acts as nucleation sites for complex carbides. With the increase of titanium content, the wear resistance of the Hardfacing alloys is increased gradually resulting from the refinement of microstructure and dispersive distribution of fine carbide precipitates. And the wear mechanism is mainly minimum plastic deformation with interrupted grooves due to the strengthening and protecting effects of carbide precipitates.
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Formation mechanism of titanium and niobium carbides in Hardfacing alloy
Rare Metals, 2016Co-Authors: Ke Yang, Yong Feng JiangAbstract:The most effective carbide-forming elements titanium and niobium were added into Hardfacing alloy. Formation and composition of carbides in the Hardfacing alloy were investigated by means of optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD) and energy-dispersive spectrometer (EDS). Hardness and impact toughness of the Hardfacing alloy were measured. The thermodynamics and formation mechanism of carbides were also discussed. It is found that the carbides consist of TiC and NbC which are able to form directly from welding pool during the welding process. The formation mechanism of carbides involves nucleation of TiC followed by epitaxial precipitation of NbC on the surface of TiC. The formation of titanium and niobium carbides can obviously refine the microstructure and deplete the carbon in the matrix. The microstructure transforms to well-distributed carbides and a tough martensite matrix, contributing to a good combination of high hardness and high toughness in the Hardfacing alloy.
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Effect of carbonitride precipitates on the solid/liquid erosion behaviour of Hardfacing alloy
Applied Surface Science, 2013Co-Authors: Ke Yang, Qin YangAbstract:Abstract The present work reports the effect of carbonitride precipitates on the solid/liquid erosion behaviour of Hardfacing alloy. Two kinds of Fe-Cr13-C Hardfacing alloy (with and without nitrogen) were deposited on a carbon steel substrate. The microstructure of the Hardfacing alloy was studied. Solid/liquid erosion tests were carried out with quartz sand particles under impact angles of 30°, impact velocity of 25 m/s for 45 min to explore the erosion behaviour of the Hardfacing alloy. It is found that the erosion damages of Hardfacing alloy were microcutting and impinging caused by the erosion of sand particles. Fine carbonitride precipitates can obviously refine the microstructure and make a dispersion strengthening effect on the matrix, leading to the enhancement of hardness of Hardfacing alloy. In addition, lots of carbonitride precipitates can effectively protect the surface of Hardfacing alloy against wearing of erosion sand particles. So the erosion resistance of Hardfacing alloy could be improved significantly owing to the strengthening and protecting effect of carbonitride precipitates, and solid/liquid erosion mechanisms were found to be microcutting and impinging with shallow grooves, fine pits and tiny lips.
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Formation of carbonitride precipitates in Hardfacing alloy with niobium addition
Rare Metals, 2013Co-Authors: Ke Yang, Qin YangAbstract:Niobium, as the most effective second-phase forming element, was added in the Fe–Cr13–C–N Hardfacing alloy to get carbonitride precipitates. Morphology and composition of carbonitride in the Hardfacing alloy were studied by optical microscopy, scanning electron microscopy, and electron probe microanalyzer. The thermodynamics and the effect on the matrix of the formation of carbonitride were also discussed. It was found that niobium carbonitrides are complex Nb(C, N) precipitate distributed on grain boundary and matrix of the Hardfacing alloy. Under as-welded condition, primary carbonitride particles were readily precipitated from the Hardfacing alloy with large size and morphology as they were formed already during solidification. Under heat treatment condition, a large number of secondary carbonitrides can precipitate out with very fine size and make a great secondary hardening effect on the matrix. As a result, addition of niobium in the Hardfacing alloy can prevent the formation of chromium-rich phase on grain boundaries and intergranular chromium depletion. The Fe–Cr13–C–N Hardfacing alloy with niobium addition has microstructure in which hard, fine niobium carbonitrides are homogeneously distributed in the matrix, and thus make a great secondary hardening effect on the matrix. And addition of niobium in the Hardfacing alloy can prevent the formation of chromium-rich phase in grain boundaries and intergranular chromium depletion.
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Improving High‐Temperature Wear Resistance of Fe–Cr13–C Hardfacing Alloy by Nitrogen Alloying
Steel Research International, 2012Co-Authors: Ke YangAbstract:Nitrogen alloying of Fe–Cr13–C Hardfacing alloy produces marked precipitation strengthening to achieve an improvement in high-temperature wear resistance. Two Hardfacing alloys of Fe–Cr13–C (with and without nitrogen) are slid on carbon steel at high-temperature of 600°C and high load of 600 N, and wear behaviors are studied systematically. It is found that abrasive wear occurrs on the surface of the Hardfacing alloy due to abrasive action of crushed oxide particles coming from the surface of carbon steel on the high temperature. The wear resistance is determined by the size and distribution of precipitates. The results show that the Hardfacing alloy can obtain a great increase in hardness and a marked decrease in wear depth of grooving due to the effect of carbonitirde precipitates. The high-temperature wear resistance of the Fe–Cr13–C Hardfacing alloy is improved by nitrogen alloying, and the wear mechanism is mainly plastic deformation with minimum depth of grooving caused by the oxide particles.
