旋压技术基本原理的研究现状与发展趋势

本文从普通旋压和强力旋压两方面综合阐述了旋压加工技术的研究进展 ,并对其今后的研究方向与研究重点进行了探讨     

A review of spinning, shear forming and flow forming processes

In the last two decades or so, spinning and flow forming have gradually matured as metal forming processes for the production of engineering components in small to medium batch quantities. Combined spinning and flow forming techniques are being utilised increasingly due to the great flexibility provided for producing complicated parts nearer to net shape, enabling customers to optimise designs and reduce weight and cost, all of which are vital, especially in automotive industries.In this paper, process details of spinning and flow forming are introduced. The state of the art is described and developments in terms of research and industrial applications are reviewed. Also, the direction of research and development for future industrial applications are indicated.     

Sheet metal forming: A review

Developments in the numerical modeling of stamping processes and experimental measurements now make it possible to design stamping processes using sound engineering principles. This article shows how experimental and theoretical contributions have led to the concept of a forming window in strain space that identifies the strains that can be developed safely in a sheet element. It is bounded by failure limits corresponding to localized necking, shear fracture, and wrinkling. A robust stamping process is one in which the strains in the part lie well within the forming window. The nature of the window and the influence of material behavior on its shape can be predicted. Editor’s Note: A hypertext-enhanced version of this article can be found at www.tms.org/pubs/journals/JOM/9911/Hosford-9911.html. For more information, contact W.F. Hosford, University of Michigan, Department of Materials Science and Engineering, 2300 Hayward Street, Ann Arbor, Michigan 48109-2136; (734) 764-3371; fax (734) 763-4788; e-mail whosford@umich.edu.     

Variational methods in the mechanics of metal forming by pressure

The strain state and forces at upsetting of an ingot, forging of a strip etc. are investigated on the basis of the minimum total power principle. Applied problems are solved with the use of direct methods. More precise and flexible is the method of reduction to ordinary differential equations. Unknown functions of a single co-ordinate are determined by solving of the system of Euler's equations for the energy functional. This approach is used for the spatial problem of investigation of the strain state of a high parallelepiped under compression.     

旋压成形技术和设备的典型应用与发展

阐述了金属旋压成形技术和设备在各个主要领域的应用与发展.详细介绍了筒形件、锥形件、封头、车轮毂、无缝整体气瓶、各式带轮、带内外纵向齿筒体、波纹管、异型件等的旋压工艺技术方案.对旋压设备的关键装置动力系统、导轨、旋轮及旋轮架等进行了介绍,并对专用轮毂旋压机、带轮旋压机、气瓶热收口旋压机、封头旋压机等先进旋压设备的应用进行了阐述.提出了旋压技术中值得探讨的表面粗糙度、高转速旋压等问题.对目前国内外旋压技术和设备的技术水平进行了对比,对今后旋压技术和设备的发展进行了展望.     

Fabrication of metal matrix composites by metal injection molding—A review

Metal injection molding (MIM) is a near net-shape manufacturing technology that is capable of mass production of complex parts cost-effectively. The unique features of the process make it an attractive route for the fabrication of metal matrix composite materials. In this paper, the status of the research and development in fabricating metal matrix composites by MIM is reviewed, with a major focus on material systems, fabrication methods, resulting material properties and microstructures. Also, limitations and needs of the technique in composite fabrication are presented in the literature. The full potential of MIM process for fabricating metal matrix composites is yet to be explored.     

Protection of steel by metal spraying: A review

Abstract

The use of sprayed metal coatings to protect steel against corrosion, although no longer novel, has become much more widespread over the last decade. Correspondingly the literature on the subject has proliferated and several Conferences have been held. This review discusses the literature dealing with the comparison of sprayed-metal coatings with other methods of protection, with the selection of coating metal, with surface preparation, application, sealing and painting. It notes recent specifications and control procedures, refers to theoretical work in progress and concludes that, for many circumstances, the correct choice of whether or not to metal spray and how to do so can now be made on a secure basis of experience. An extensive bibliography (110 references) covering the last few years is included.     

Bioleaching: A microbial process of metal recovery; A review

The present review describes the historical development and mechanisms of bioleaching. Recent development has shown commercial application of the process and, concurrently, details pertaining to the key microorganisms involved in these processes have been described. Bioleaching of metal sulfides is caused by diverse groups of bacteria. The dissolution biochemistry signifies two types of pathways, which are specifically determined by the acid-solubility of the sulfides, the thiosulfate and polysulfate pathways. This sulfide dissolution can be affected by ‘direct’ and ‘indirect’ mechanisms. In the ‘indirect’ mechanism bacteria oxidize only dissolved iron (II) ions to iron (III) ions and the latter can then attack metal sulfides and then be reduced to iron (II) ions. The ‘direct’ mechanism requires the attachment of bacteria to the sulfide surfaces. In the case of thiobacilli, bacteria secrete exopolymer that facilitates attachment of the bacteria to a metal surface, thus enhancing the leaching rate. In terms of eco-friendliness and process economics, within the field of biohydrometallurgy the technology is considered robust.     

金属管材冷旋压成形过程的三维有限元数值模拟

依据有限元理论,对金属管材冷旋压成形过程进行了数值模拟,得出了在不同旋轮工作角下变形区的应力、应变分布规律。分析了影响成形质量的各种因素,计算了旋压力。为有效的进行旋压技术参数确定、工艺优化以及定量控制提供了可靠的方法和依据。