Papers by Keyword: Warm Extrusion

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Authors: Vanessa Livramento, Jose Brito Correia, Filipe Neves, Rosa Calinas, M. Teresa Vieira
Abstract: Copper nitride films prepared by sputtering have applications such as optical data storage material, insulation barriers in micro electronic devices and coatings for mechanical applications. The present study examines nanocomposites prepared by mechanical alloying of copper with copper nitride under nitrogen atmosphere, at room temperature, in order to establish a comparison with properties of Cu-N sputtered films. The powders were consolidated into bulk samples via warm extrusion at temperatures ranging from 300 to 500°C (0.42-0.64 Tf) after encapsulation without degassing. The as-milled powders and the extruded materials were studied using X-ray diffraction, optical microscopy, scanning and transmission electron microscopy and microhardness measurements. Also, the TEM observation of the extruded sample indicates a mean grain size of about 50 nm. This evidences a higher thermal stability of the as-milled powders and the advantage of using a fast consolidation process, at a relatively low temperature. Therefore, the consolidated material did not show the dramatic softening associated with recrystallization. The consolidation of nanostructured copper-copper nitride composite powders via warm extrusion, without major grain coarsening, was demonstrated.
177
Authors: Shu Bo Xu, Ke Ke Sun, Cai Nian Jing, Yu Shuang Huo, Gui Qing Wang
Abstract: In this paper, influence of temperature on warm temperature equal channel angular of AZ31 alloy was investigated by using numerical simulation and experimental investigation. The effective stress distribution rules and load-stroke curves viartions were obtained at different temperature. And the distribution of effective strain and the rules of deformation uniformity of three temperatures extrusion processing for round workpiece are obtained. The proper temperatures extrusion processing is acquired through comparing the results of three extrusion routes. The effect of the temperature on the accelerated grain refining during the ECAE operation was discussed in the numerical calculations with a view to the use of the process to bulk AZ31 alloys. On the basis of the simulations, the warm ECAE experiments are carried out. The geometries of finally pressed workpieces of the different temperature pressed samples are in good agreement with finite element analysis results.
296
Authors: An Min Zhang
Abstract: In this study, the true working conditions of a warm extrusion die was simulated using DEFORM-3D software; images of the die’s temperature, stress, and wear distributions were obtained, the amount of wear of the die cavity were calculated, and the wear depth curves were drawn for each test point on the basis of this simulation. A production analysis along with the simulation revealed the main forms of early failure for the warm extrusion mold to be cracking failure, collapsing failure, and wear failure. Through data analysis, the areas of the die that cracked easily or showed heavy wear were identified. The steps required to prevent early failure are proposed in this article.
68
Authors: Xin Ju Zhang, Xiu Hong Ma, Fu Xiang Zhang, Hui Qin Cao
Abstract: There are three work posts in this warm extruder: upsetting station backward extrusion station and blanking station. They work continuously. The manipulator is mainly used to passing artifacts from one station to another. The warm extrusion forming process manipulator for steel connecting sleeve typically was designed to reduce labor intensity and enhance production automation level. The machines structure and working principle were described. In the same time, the machine control system that adopts the PLC programmable controller can simplify the control system, and its reliability strengthens further. Practices show that the strapping machine has the advantages of simple structure, high efficiency, low cost and small vibrating noise.
678
Authors: Xin Ju Zhang, Zhao Min Yang, Song Lin Yang
Abstract: There are three work posts in this warm extruder: upsetting station, backward extrusion station and blanking station. They work continuously. The manipulator is mainly used to passing artifacts from one station to another. The warm extrusion forming process manipulator for steel connecting sleeve typically was designed to reduce labor intensity and enhance production automation level. The machines structure and working principle were described. In the same time, some pneumatic circuits and pneumatic control circuits of the manipulator were designed, so the manipulator can have automatic voltage regulating function and run smoothly. Practices show that the strapping machine has the advantages of simple structure, high efficiency, low cost and small vibrating noise.
978
Authors: Yun Wang, Zhen Ying Xu, Pei Long Dong, Guo Ding Yuan, Lan Cai
Abstract: The rapid market need of MEMS (Micro Electromechanical System) and metal microparts are increasing gradually. The plastic microforming has received more interests and applications in MEMS because it ensures high precision and manufacturing efficiency. However, it raises the higher demand on the microforming and plastic processing technology. Here we present one new process to micro-extrude microparts with laser-aided heating method. The new process is to selectively heat the workpiece with the laser radiation method to the suitable temperature that is between room temperature and recrystallization temperature, and to extrude the workpiece. This process is characterized by decreasing the influence of strain strengthening and lowering the resistance to deformation, and increasing the uniformity of material flow. The key elements of the approach concerning the warm micro-extrusion and temperature control, such as process parameters, laser heating system, micro-extrusion die structure, have been advanced. Furthermore, an important aspect of the research is that the developed system and theory of micro warm extrusion based on laser heating can be explored for further investigation and understanding of plastic microforming.
462
Authors: Chun Jian Su, Quan Lan Li, Lin Jing Xiao, Su Min Guo
Abstract: Cutting pick is a kind of widely-used consumptive mining tool. The traditional producing technics of cutting pick body is foundry, or machining after roughly forging, or machining directly from metal bar. By former technics, the property of products is poor, and by latter, the material availability is low and the cost is high. The patent technology for cutting pick body warm extrusion introduced in this paper can overcome all the disadvantages mentioned above. In this paper, by analyzing the characteristic of cutting pick body warm extrusion, adopting the principle of power balance to solve the approximate solution of strain forces, the approximate calculating formulas of extruding power are deduced. The main factors affecting on extrusion force are determined theoretically. This research can be used as basis to design tooling and choose proper equipment for this new technology.
1061
Authors: Guo Cheng Ren, Guo Qun Zhao, Shu Bo Xu
Abstract: This article investigated deformation behavior and microstructure of AZ31 magnesium alloy in equal channel angular pressing (ECAP) process at 250 C. The proper process parameters were obtained through investigating the deformation behavior and properties of AZ31 magnesium alloy by using finite element (FE) simulation under different deformation conditions. The ECAP experiments were also carried out by using the optimized design of the channel die. The micro-structures of experimentally pressed work-pieces are in good agreement with finite element analysis results. The research results provided reliable basis for the further development and use of magnesium alloy precision forming.
227
Authors: Ting Liu, Xue Wen Chen, Shu Li Pei
Abstract: Static stents is the switch component that plays the role of fixing and supporting. It will received impact, the attrition and reverse function in the work process, which requires high mechanical properties to meet their work requirements. This paper uses the forming technology of "the pre-formation +warm extrusion + cold finishing "to form the static support ,and it carries on the numerical simulation and optimization analysis, which not only improve the work piece performance greatly and reduce the manufacturing cost.
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