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The wear behaviours of G20CrNi2MoA carburised steel under different temperature

International Journal of Computational Materials Science and Surface Engineering 2020年第2期9卷 134-146页

作者： Zeng, Songwen Qian, Dongsheng Wang, Feng School of Materials Science and Engineering Wuhan University of Technology Wuhan430070 China Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan430070 China Hubei Engineering Research Center for Green Precision Material Forming Wuhan430070 China

The wear behaviours of G20CrNi2MoA carburised steel under different temperature was investigated in this work. The microstructure and morphology of the worn surface and cross-section of the specimen were characterised by scanning electron microscope (SEM). It is found that the average friction coefficient increases from 0.464 to 0.563 and the wear rate increases from 3.0 × 10–6 mm3N–1m–1 to 21.1 × 10–6 mm3N–1m–1 with the increase of temperature from room temperature (RT) to 200oC. The percentage of oxygen content on the worn surface increases from 11.66% to 36.12% with the increasing temperature, and the main wear mechanism changed from abrasive wear to oxidation wear. The average diameter of the carbides at the subsurface increases from 0.16 μm to 0.24 μm with the increase of temperature. Additionally, the micro crack and voids can be found around the large carbides at 200oC, resulting in the increase of wear rate. Copyright © 2020 Inderscience Enterprises Ltd.

关键词： Carbides

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Research on Fractional-Order Control of Anchor Drilling Machine Optimized by Intelligent Algorithms

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Applied Sciences 2025年第10期15卷 5656-5656页

作者： Jingkai Li Jun Zhang Jiaquan Xie Wei Shi Jianzhong Zhao College of Mining Engineering Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of In-Situ Property-Improving for Mining of Ministry of Education Taiyuan University of Technology Taiyuan 030024 China College of Mechanical Engineering Taiyuan University of Technology Taiyuan 030024 China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of Education Taiyuan University of Technology Taiyuan 030024 China School of Mathematics and Statistics Taiyuan Normal University Jinzhong 030619 China

Anchor–bolt support operations are lengthy and conducted under harsh conditions, restricting the efficiency and safety of roadway excavation. To address these challenges, we developed an integrated solution combining mechanical structure optimization with control algorithms. Specifically, we designed a novel automated drilling system equipped with a robotic manipulator and an anchor–bolt magazine to handle modular hollow self-drilling anchor bolts, enabling automated support operations. To achieve precise docking in unmanned conditions, we employed an inner-loop fractional-order proportional–integral–derivative (FOPID) controller optimized by an improved particle swarm optimization (ILPSO) algorithm. Additionally, robust control based on H∞ control theory was introduced to ensure reliable system performance under disturbances and model uncertainties. Simulation results indicate that the ILPSO-tuned FOPID controller significantly outperforms conventional controllers in dynamic response accuracy; frequency–domain analysis further confirms that the H∞ control approach enhances system stability. Collectively, these results provide a theoretical basis for advancing automated mining technologies.

关键词： anchor bolting automated drilling rig fractional-order PID control improved particle swarm optimization H∞ robust control

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Frontier and application basic research program of chongqing science and technology commission

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Materials 2020年第11期13卷

作者： Li, Jingjing Ju, Jiang Chang, Weiwei Yang, Chao Wang, Jun School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai200240 China Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University Shanghai200240 China Institute for Advanced Materials and Technology University of Science and Technology Beijing Beijing100083 China

In this study, a high aluminum and chromium Fe-B-C coating was prepared using laser cladding on 2Cr13 steel substrate. The microstructure, microhardness, and wear resistance of the high aluminum and chromium Fe-B-C coating were investigated. The results show that this dense coating possesses good metallurgical bond with the substrate. The microstructure is mainly composed of α-(Fe, Cr, Al) lath martensite, orthorhombicM2B boride, orthogonalM3C2, and orthorhombicM7C3 carbides. The microhardness of the coating can reach 620 HV which is 3.3-times higher than that (190 HV) of the substrate. The coating shows a lower friction coefficient of 0.75 than that of the substrate (1.08). The wear rates of the substrate and the coating are 0.295 mg/min and 0.103 mg/min, respectively, indicating the coating exhibits excellent wear resistance. The wear mechanism transforms severe adhesive wear and abrasive wear of the substrate to slight abrasive wear of the coating. The results can provide technical support to improve the properties of the Fe-based laser cladded coating. © 2020 by the authors.

关键词： Microstructure

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Finite element simulation and microstructure of two-pass inner spinning process of curved-generatrix cone cylindrical parts with annealing/quenching

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Journal of Central South University 2019年第12期26卷 3305-3314页

作者： HAO Zeng-liang YANG Zhe-yi) WEI Wei LIU Lei LUO Jun-ting LIU Jin-heng Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of Education Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China Hebei Construction Material Vocational and Technical College Qinhuangdao 066000China

A two-pass annealing/quenching internal spinning process with small-end rotations is proposed to form a curved generatrix conical thin-walled *** is,annealing at 360°C for 2 h followed by the 1st pass spinning,and finally quenching in ice water after holding for 1 h at 498°C followed by the 2nd pass *** finite element software is used to simulate the internal spinning process of the products formed under different forming *** distribution laws of spinning force,the stress and strain under different forming processes were compared and *** mechanical properties and microstructure of the products are subsequently *** results show that the strain and the residual stress in the skin area of the formed products under two-pass spinning process more uniform,and the hardness and the mechanical performance are *** microstructure of the products formed with the 0.15 mm thickness reduction at the 2nd pass is *** the second phase grain size distributed uniformly in the range of 36μ***,the second phase particles are broken seriously and the size distribution inhomogeneity is increased when the thickness reduction in the skin area is greater than 0.20 mm at the 2nd pass spinning process.

关键词： curved generatrix conical internal spinning process annealing/quenching small-end rotations finite element simulation

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On the formation mechanism of Cr nitrides in an additively manufactured duplex stainless steel

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Materials Characterization 2025年 227卷

作者： Junyao Guo Haokai Dong Wenzheng Liao Wei Guo Jiantao Zhang Keke Chang State Key Laboratory of Advanced Marine Materials Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences Ningbo 315201 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing 100049 China National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials South China University of Technology Guangzhou 510640 China Guangzhou City University of Technology Guangzhou 510800 China

Cr nitrides are usually considered as a detrimental phase to corrosion resistance and mechanical properties of duplex stainless steels (DSSs), while their formation mechanism in non-equilibrium conditions is not yet fully understood. This study revisits the precipitation behaviors of Cr nitrides in a 2205 DSS fabricated via selective laser melting (SLM). It reveals that the nanoscale enrichments of Cr and N at both the grain boundaries (GBs) and the surface of intragranular nano-inclusions are CrN of B1 structure, while the Cr 2 N (hexagonal structure) forms mainly at the GBs. Direct experimental evidence for topological transformation from CrN to Cr 2 N is provided. The competitive precipitation behavior of nitrides from the supersaturated ferrite is quantitatively addressed by thermodynamic and first-principles calculations. Impressively, the much lower strain energy shared on both sizes of ferrite and particle is the main cause for the priority precipitation of CrN, albeit Cr 2 N is thermodynamically more stable. The present study provides both experimental and theoretical basis for the precursor role of CrN in Cr 2 N precipitation.

关键词： Cr nitrides Duplex stainless steel First-principles calculations Non-equilibrium precipitation Strain energy

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Finite element simulation and experimental test of the wear behavior for self-lubricating spherical plain bearings

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Friction 2018年第3期6卷 297-306页

作者： Yahong XUE Jigang CHEN Sumin GUO Qingliang MENG Junting LUO School of Mechanical Engineering Yanshan University Aviation Key Laboratory of Science and Technology on Generic Technology of Self-Lubricating Spherical Plain Bearing Yanshan University Education Ministry Key Laboratory of Advanced Forging and Stamping Technology and Science Yanshan University

In this study, based on the classical Archard adhesion wear theory, a three-dimensional finite element model was established, with the aim of simulating the failure process of self-lubricating spherical plain bearings in the swinging wear condition. The results show that the self-lubricating spherical plain bearings go through two different stages during the wear process, namely, initial wear stage and stable wear stage. Because the large contact points wear out during the initial wear stage, the maximum contact pressure decreases as the test period increases. The relatively larger wear depth region shows elliptical distribution, and the maximum distribution appears in the central contact area. The wear depth reaches 0.974 mm after swinging 25,000 times. PTFE fibers, which possess a good friction performance but poor abrasion resistance, abundantly exist on the friction surfaces of the fabric liner. Consequently, the friction torque during the initial wear stage is slightly smaller than the friction torque during the stable wear stage; however, the wear rate during the initial wear stage is high. The reliability and effectiveness of the finite element model are verified by experiment. The developed finite element model can be used for the analysis of the wear mechanisms of bearings and the prediction of the service life of bearings.

关键词： spherical plain bearing wear mechanisms wear depth contact pressure simulation

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Effect of Cu/Mg-Containing Intermetallics on the Mechanical Properties of the As-Cast HVDC AlSiMgMnCu Alloys by SBFSEM at Nano-Scale

SSRN

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SSRN 2022年

作者： Liu, Fei Zhao, Haidong Zhong, Yan Jiang, Yuanhang Li, Xiang Chen, Bo Zheng, Huiting National Engineering Research Center of Near-net Shape Forming for Metallic Materials South China University of Technology Guangzhou510641 China Key Laboratory of Advanced Civil Engineering Materials Ministry of Education School of Materials Science and Engineering Tongji University Shanghai201804 China Shanghai Highway Investment Construction and Development Co. Ltd. Shanghai200336 China London Centre for Nanotechnology University College London LondonWC1H 0AH United Kingdom

In this study, AlSiMgMnCu alloys with different Cu and Mg contents were fabricated by high vacuum die casting (HVDC) technique. The phase formation and their microstructure evolution are quantitatively studied by serial block-face scanning electron microscopy (SBFSEM) at nano-scale in three-dimensions (3D). Through analyzing their 3D microstructure, effects of the spatial distribution, volume fractions and morphology of the intermetallic phases on the alloy’s mechanical properties are comprehensively discussed. It is found that, with higher Cu content and lower Mg content, the nucleation and growth of θ-Al2Cu phase would have advantage over Q-Al5Cu2Mg8Si6 phase. In contrast, decreasing Cu/Mg ratio by increasing Mg content is in favor of the nucleation and growth of the Q-Al5Cu2Mg8Si6 phase. The uniformly distributed fine θ-Al2Cu phase provides the highest contribution to the strengthening of the HVDC AlSiMgMnCu alloys. For the Cu/Mg ratio to be 3, an as-cast HVDC Al-10Si-0.2Mg-0.5Mn-0.6Cu alloy with optimized ultimate tensile strength, yield strength and elongation of 330 MPa, 162 MPa and 10.2%, respectively, had been produced. © 2022, The Authors. All rights reserved.

关键词： Scanning electron microscopy

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Effect of Si and Ti on dynamic recrystallization of high-performance Cu-15Ni-8Sn alloy during hot deformation

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Transactions of Nonferrous Metals Society of China 2019年第12期29卷 2556-2565页

作者： Chao ZHAO Zhi WANG De-qing PAN Dao-xi LI Zong-qiang LUO Da-tong ZHANG Chao YANG Wei-wen ZHANG Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of TechnologyGuangzhou 510640China School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China

Effect of Si and Ti on dynamic recrystallization(DRX)of Cu-15Ni-8 Sn alloy was studied using hot compression tests over deformation temperature range of 750-950℃and strain rate range of 0.001-10 s^-*** results show that the dynamic recrystallization behavior during hot deformation is significantly affected by the trace elements of Si and *** addition of Si and Ti promotes the formation of Ni16Si7Ti6 particles during hot deformation,which promotes the nucleation of dynamic recrystallization by accelerating the transition from low-angle boundaries(LABs)to high-angle boundaries(HABs).Ni16Si7Ti6 particles further inhibit the growth of recrystallized grains through the pinning *** on the dynamic recrystallization behavior,a processing map of the alloy is built up to obtain the optimal processing *** by the processing map,a hot-extruded Cu-15 Ni-8Sn alloy with a fine-grained microstructure is obtained,which shows excellent elongation of 30%and ultimate tensile strength of 910 MPa.

关键词： Cu-15Ni-8Sn alloy discontinuous dynamic recrystallization hot compression hot extrusion mechanical properties

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Yield Characteristics Strengthening and Yield Strength Anti-Dispersion Identification Based on Bending Deformation

Research Square

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Research Square 2020年

作者： Duan, Yong-Chuan Qiao, Hai-Di Zhang, Fang-Fang Liu, Yu Tian, Le Yang, Liu Guan, Ying-Ping Key Laboratory of Advanced Forming & Stamping Technology and Science Ministry of Education of China Yanshan University Hebei Qinhuangdao066004 China College of Mechanical Engineering Yanshan University Hebei Qinhuangdao066004 China

The online derivation of material yield is important for consistency control of product quality. Compare with other deformation, bending deformation is more suitable for online identification. The transition portion of bending force stroke curve is related to the yield strength of material, but for a wide set of materials with different thickness and properties, its longer transition curve shows higher identification scattering. In this paper, the yield characteristics strengthening method and the new anti-dispersion identification method are studied to reduce the scattering. It is found that the yield characteristics are comprehensively affected by several factors. The higher yield strength, together with thinner thickness, can weaken the yield characteristics. The thicker material with wider die span can strengthen the yield characteristics. Window vector method (WV) and standardized fitting residual method (SFR) are proposed. Through the numerical study found that the yield load obtained by WV method shows a most accurate correlation with yield strength. A novel piecewise correlation equation is proposed and added a thickness variable to eliminate partial dispersion from varied thickness. Furthermore, this paper uses the experimental data to extract the generalization error of new correlation model fitted by yield loads from WV method, maximum error is below 12%. This method can improve the accuracy and efficiency of online ranking materials. © 2020, CC BY.

关键词： Yield stress

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Precision and Flexible Bending Control strategy Based on Analytical Models and Data Models

Research Square

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Research Square 2020年

作者： Duan, Yong-Chuan Zhang, Fang-Fang Liu, Yu Qiao, Hai-Di Yang, Liu Guan, Ying-Ping Key Laboratory of Advanced Forming & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao Hebei066004 China College of Mechanical Engineering Yanshan University Qinhuangdao Hebei066004 China

forming of various customized bending parts, small batches, as well as numerous types of materials is a new challenges for Industry 4.0, the current control strategies can not meet the precision and flexibility requirement, expected control strategy of bending processes need to not only resist unknown interferences of process condition and models, but also produce various new parts automatically and efficiently. In this paper, a precision and flexible bending control strategy based on analytical models and data models is proposed to built adaptive bending systems. New analytical prediction models for loading and unloading are established and suitable for various materials, a sequential identification strategy is proposed to search nominal properties using the four sub-optimization models. A data-based feedback model is established to prevent over-bending and eliminate online deviation. Above models are merged into a precision and flexible control strategy. the system firstly uses sub-optimization models to search the nominal point which is near to target point, secondly the system further uses feedback model to eliminate residual error between the nominal point and target point. Compared with four kinds sheet metals, the allowable ranges for variables are determined for a good convergence. The target bending angles were set to 20°, 40°, and 60°. Forty parts were tracked for each kind material, the adaptive bending system converged after one iteration, and exhibited better performances. © 2020, CC BY.

关键词： Analytical models

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