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Yu J.,Chongqing University | Liu J.,Chongqing University | Chen X.,China National Erzhong Group Co. | Liu J.,China National Erzhong Group Co.
Applied Mathematics and Information Sciences | Year: 2011

According to the special requirements of Sheet Molding Compound (SMC) a set of quadrangular leveling system is designed, whose leveling precision is controlled by electro-hydraulic proportional technology. Based on analyzing the components and working principle of the quadrangular leveling system, the mathematical model of this system is established. The dynamic characteristics of stability and anti-interference are simulated and analyzed. The results show that the main factors that can affect the dynamic characteristics of system are obtained and the system completely meets technical requirement after being corrected, the work in this paper can provide a high guidance for presses of similar kinds. © 2011 NSP. Source

Huang S.-Q.,Central South University | Yi Y.-P.,Central South University | Li P.-C.,China National Erzhong Group Co.
Fenmo Yejin Cailiao Kexue yu Gongcheng/Materials Science and Engineering of Powder Metallurgy | Year: 2013

The static recrystallization behaviors of 23Co13Ni11Cr3Mo ultrahigh strength steel were investigated by GleebIe-1500 machine. Effects of deformation temperature, strain rate, deformation degree, interval time and initial austenite grain size on static recrystallization behaviors were studied. The results show that the effect of deformation degree is more significant, while those of strain rate and initial austenite grain size are little slight. Small and even grain can be achieved by increasing deformation degree. Based on experimental results, grain size model of static recrystallization for 23Co13Ni11Cr3Mo steel was developed. Microstructure evolution of landing gear during integer die forging on hammer press was analyzed quantitatively by the established model. Static recrystallization under low deformation degree is found to be the reason for grain dissatisfaction. And a good fitness between experimental results and predicted results is achieved in landing forging process. Source

Yang J.-D.,Chongqing University | Wu J.-Q.,Chongqing University | Deng Y.,China National Erzhong Group Co.
Advanced Materials Research | Year: 2011

The article gives a solution to the precise synchronous control of multi-hydraulic cylinders which exist in the large-sized pressure and flattening machine by the virtual axis method. To fulfill the job, the scheme introduces the acceleration feedback to the virtual control model to make the model practical. According to the Newton's mechanical law and fluid mechanic, the article set up the model mentioned above. The control system presented is investigated through simulation of Matlab under step disturbance and productive practice which successfully demonstrate the effectiveness of the proposed control model. © (2011) Trans Tech Publications, Switzerland. Source

Xu J.,Lanzhou University of Technology | Chen J.,Shaoxing Testing Institute of Quality Technical Supervision | Yang S.,Lanzhou University of Technology | Zhang L.,Lanzhou University of Technology | Lu J.,China National Erzhong Group Co.
International Journal of Nanoparticles | Year: 2010

Copper nanoparticles are prepared by electrochemical method with various current density in emulsion containing sodium dodecyl sulfate, tween80, dodecyl mercaptan, CuSO4·5H2O. The resulting copper nanoparticles are investigated by XRD, TEM and FT-IR. The result shows that great changes have taken place in the size, the dispersibility, and the distribution of particles size as the current density goes up. According to analysis, it can be found that the copper nanoparticle can be obtained in smaller size, better dispersibility and narrower distribution of particle size under the current density of 0.01 A/cm2. At the same time, current density eventually affects the size of the nanoparticles as well as overpotential and the size of water droplet. © 2010 Inderscience Enterprises Ltd. Source

Quan G.-Z.,Chongqing University | Lv W.-Q.,Chongqing University | Liang J.-T.,Chongqing University | Pu S.-A.,Chongqing University | And 2 more authors.
Journal of Materials Processing Technology | Year: 2015

The hot workability of as-forged Ti-10V-2Fe-3Al alloy was evaluated. Meanwhile, the intrinsic relationships between deformation mechanisms and processing parameters were determined by the processing maps on the basis of dynamic materials model (DMM) with the input stress-strain data collected from a series of isothermal compressions at temperatures of 948-1123 K (across β-transus) and strain rates of 0.001-10 s-1. At the beginning, at a set of discrete true strains the response maps of strain rate sensitivity exponent (m-value), power dissipation efficiency (η-value) and instability parameter (ξ-value) to temperatures and strain rates were developed respectively. Following that, a processing map corresponding to each true strain was constructed by superimposing an instability map over a power dissipation map. According to m-criterion, η-criterion and ξ-criterion, the stable regions with higher power dissipation efficiency (η > 0.3) and unstable regimes with negative strain rate sensitivity exponent and instability parameter (m < 0 and ξ < 0) were clarified clearly. Moreover, the deformation mechanism map was established, based on which the parameter domains corresponding to different deformation mechanisms were identified. By the criteria of two main stable strain-softening mechanisms, i.e. globularization and dynamic recovery (DRV), the globularization-predominant parameter domain in α+β-phase temperature range and DRV-predominant parameter domain in β-phase temperature range were identified and recommended. In a wide temperature range across β-transus and a large strain rate range, the clarification of stable and unstable parameter regions corresponding to different deformation mechanisms contributes to design in the various hot forming processes of Ti-10V-2Fe-3Al alloy without resorting to time-consuming trial-and-error procedures. © 2015 Elsevier B.V. All rights reserved. Source

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