Luan Vocation Technology College

Luancheng, China

Luan Vocation Technology College

Luancheng, China
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Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Quan X.,Luan Vocation Technology College | Shen J.,Tianjin University of Technology
Surface and Coatings Technology | Year: 2017

Laser cladding VN alloy/Co-based composite coatings on a mild steel substrate were heat treated at 650 °C for 3 h and 5 h, respectively. Effect of heat treatment on microstructure and wear resistance of the composite coatings was investigated systematically by optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, micro-hardness testing and wear testing. The results showed that as-laser cladded and heat treated VN alloy/Co-based composite coatings were all composed of γ-Co, Cr23C6, σ-FeV, Co5.47N and VN phases. The intensities of γ-Co diffraction peaks were reduced gradually and the intensities of Cr23C6 and VN diffraction peaks were increased gradually with the increasing of heat treatment time. Lots of short rod-shaped dendrites and more uniform equiaxed grains exhibited in the composite coatings after heat treatment. The microhardness and wear resistance of VN alloy/Co-based composite coatings were reduced slightly after heat treatment for 3 h. The microhardness and wear resistance of the composite coatings were improved by 6.71% and 9.82%, respectively, for heat treatment for 5 h. The wear mechanism of three composite coatings was all the abrasive wear. © 2017


Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Quan X.,Luan Vocation Technology College | Shen J.,Tianjin University of Technology
Materials Characterization | Year: 2017

Laser cladding VN alloy reinforced Co-based composite coatings on the mild steel was aging treated at 550 °C, 650 °C and 750 °C, respectively. Effects of aging temperature on the phase compositions, microstructure, microhardness, and wear resistance of the composite coatings with and without heat treatment had been investigated systemically. The results showed phase compositions of the composite coatings were not affected after aging treatment at 550 °C and 650 °C, and σ-FeV phase was not detected after aging treatment at 750 °C. The volume fraction of Cr23C6 and VN was gradually increased with the increasing of aging temperature. The number of short rod-shaped dendrites and equiaxed grains in the composite coatings was gradually increased as aging temperature increased, the distribution of the equiaxial grains was more uniform, and the dislocation density was reduced. Compared with the composite coatings without aging treatment, the microhardness and wear resistance of the composite coatings were both firstly decreased after aging treatment at 550 °C and 650 °C, then gradually increased with the increase of aging temperature, and the increase was 9.9% and 10.7%, respectively, for aging treatment at 750 °C. The wear mechanism of three composite coatings were all the abrasive wear. © 2017


Quan X.-M.,Luan Vocation Technology College | Liu R.-F.,Luan Vocation Technology College | Han S.-P.,Luan Vocation Technology College | Huang H.-B.,Luan Vocation Technology College
Zhuzao/Foundry | Year: 2015

Co-based alloy coatings with V-N alloy addition clad on the surface of the low carbon steel were treated by aging. The microstructure and phases of the coatings were studied and analyzed with optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD) instrument. The micro-hardness and sliding wear resistance of the coatings were also tested. The results show that the phase structures of VN alloy/Co-based coating are still composed of γ-C0, Cr23C6, Co5.47N and σ-FeV, but peak height from 40-50° is decreased. With the increase of aging temperature, the micro-hardness and wear resistance of the coatings are all improved. The results provide a reference for application of aging treatment after the laser cladding. ©, 2015, Chinese Mechanical Engineering Society. All right reserved.


Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Quan X.,LuAn Vocation Technology College | Shen J.,Tianjin University of Technology
Journal of Alloys and Compounds | Year: 2016

VN alloy/Co-based composite coatings were prepared on the mild steel substrate by laser cladding. The effect of different amounts of VN alloy on the microstructure and wear resistance of Co-based coatings was investigated systematically by optical microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, micro hardness testing and wear testing. The results showed phases of Co-based cladding coatings after adding VN alloy were γ-Co, Cr23C6, Co5.47N, σ-FeV and VN. A certain amount of fine grains and polygonal equiaxed grains synthesized as well as dense stacking fault and interaction of stacking fault were formed after adding VN alloy. The microhardness and wear resistance of coatings both improved greatly with a moderate additional amount of VN alloy. The improvement in microhardness and the reduction in wear loss were 12.0% and 36.4%, respectively, for 5.0 wt.% VN alloy, and the wear mechanism was abrasive wear. Thus, it is concluded that adding VN alloy is an effective and attainable way to improve the wear resistance of Co-based coatings. © 2015 Elsevier B.V.


Ding L.,Tianjin University of Technology | Hu S.,Tianjin University of Technology | Quan X.,Luan Vocation Technology College | Shen J.,Tianjin University of Technology
Applied Physics A: Materials Science and Processing | Year: 2016

Three kinds of coatings were successfully prepared on Q235 steel by laser cladding technique through adulterating with Mo and nano-Nd2O3 into Ni-based alloys. The effect of Mo and nano-Nd2O3 on the microstructure and properties of Ni-based coatings was investigated systematically by means of optical microscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and microhardness testing and wear testing. The results indicated a certain amount of fine grains and polygonal equiaxed grains synthesized after adding Mo and nano-Nd2O3. Both the microhardness and wear resistance of Ni-based coatings improved greatly with a moderate additional amount of Mo and nano-Nd2O3. The largest improvement in microhardness was 31.9 and 14.7 %, and the largest reduction in loss was 45.0 and 30.7 %, respectively, for 5.0 wt% Mo powders and 1.0 wt% nano-Nd2O3. The effect of Mo on microhardness and wear resistance of laser cladding Ni-based alloy coatings is greater than the effect of nano-Nd2O3. © 2016, Springer-Verlag Berlin Heidelberg.


Wei X.,Luan Vocation Technology College | Fu L.,Shanghai JiaoTong University | Liu S.,Shenyang Research Institute of Foundry | Wang W.,Baosteel | Shan A.,Shanghai JiaoTong University
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2013

A physical model has been established to predict the stress-strain relations during the deformation of the two-phase materials, in which the effect of grain size and volume fraction of the phases on the change in strain and stress are completely considered. The predictions are good agreement with the experimental results. The micro-stress-strain partitioning between martensite (hard phase) and ferrite (soft phase) was quantitatively analyzed in the martensite-ferrite dual-phase steel. It is shown that the grain size and volume fraction greatly influence the stress-strain partitioning of the constituent phases. The stress ratio of the hard to soft phase decreases with the increase of the hard phase volume fraction. The strain ratio of the soft to hard phase increases before the plastic deformation of the hard phase starts when the relative macro-strains is applied. However with the macroscopic strain increasing, the hard phase begins to plastically deform and the strain ratio gradually reduces and eventually approaches to a constant. And the steel with relatively higher volume fraction of the hard phase has the relatively smaller constant value. In the case of a definite volume fraction, increasing the relative grain size of the hard phase contributes to the increase of the overall plasticity of the steel, while reducing the relative grain size of the hard phase helps to improve the overall strength of the steel. The optimal performance of the steel is achieved only when the grain size ratio of hard to soft phase is controlled within an appropriate range where each of constituent phases plays its most potential value.


Huang H.,Luan Vocation Technology College | Wang Y.,Anhui University of Technology | Fan T.,Anhui University of Technology
Advanced Materials Research | Year: 2012

The wheel-legged rover with a double-half-revolution mechanism uses two tandem planetary gear trains to drive. Its virtual prototype model was built in COSMOS Motion software, and the mechanical data of each gears of the wheel-legged rover were obtained by dynamic simulation under the typical working conditions. On this basis, the finite element analysis model of the wheel-leg planetary gear was established and its stress analysis was done. The discrete optimization mathematical model was built with the optimization target of minimizing the rover's wheel-leg planetary gear volume and the constraint condition of keeping the Mises stress applied on the dedendum under the admissible Mises stress. Based on ANSYS Parametric Design Language (APDL), the optimization design was done for the above gear based on discrete optimization method. The result shows that the optimized gear not only meets the strength requirement, but also its weight is 58% lower than the original, which will provide a new effective method for optimizing the wheel-leg structure of the rover. © (2012) Trans Tech Publications.


Huang H.B.,Luan Vocation Technology College | Wang Y.M.,Anhui University of Technology | Xia S.,Anhui University of Technology
Applied Mechanics and Materials | Year: 2014

With the spindle system of a vertical gantry machining center as the research object, the paper is based on the vibration theory and finite element method and the mainly work is study on modal analysis of spindle system. First finite element models of the mandrel, box body and motorized spindle frame of spindle system are established by ANSYS. And then do the modal analysis of singleton in the boundary of free constraint. Lastly based on the analysis results to establish the finite element model of the whole spindle system and do the modal analysis of the whole system which under constraint condition. The result shows that the swing of motorized spindle frame and motorized spindle sleeve of spindle system are more obvious. © (2014) Trans Tech Publications, Switzerland.

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