Modification of metal spinning forming and rapidly developing technology, its features are as follows: (1) precision plastic forming technology has developed rapidly, with a high precision forming, process simple and efficient, saving advantages of raw materials; (2) metal material forming processes in the "control-shaped" and "control" of equal importance, by stressing the shape and dimensional accuracy, while also focusing on the control of materials and properties; (3) the use of a computer simulation of virtual manufacturing technology to flourish, for plastic forming and reforming the the development of new technology laid the foundation. The following combination of Harbin Institute of Technology School of Materials Science and Engineering related research on plastic deformation and modification of metal materials, new technologies briefly.
A new type of plastic forming technology
1.1 Viscous pressure forming technology
Viscous pressure forming (VPF) is the United States in 1994 for the defense industry made a high-intensity difficult to process material forming technology. Semi-solid, can be mobile and have a certain viscosity, and rate-sensitive material (known as viscous) as the soft mode, you can board one side or both sides of the same time impose viscous, so that the pressure plate in the one-way or two-way pressure At the same time under the action of forming. Viscous forming process capable of withstanding high pressure, flow and filling good, easy-to-sealing and injection and emission control, so that better billets into the cavity to avoid a serious localized wall thinning, for high-intensity, low - shaping of complex surface deformation is difficult, and high dimensional accuracy, good surface quality of the forming of sheet metal parts to provide advanced manufacturing technology. Harbin Institute of Technology researchers have succeeded in relating this approach to high-temperature alloys used in thin plate-shaped pieces of corrugated forming, aluminum alloy ladder parts forming plate, stainless steel hemispherical shell shape.
Plate surface pressure distribution can be controlled to improve the sheet formability. Viscous by regulating the injection and emission control, you can real-time control of sheet forming process of mold cavity pressure on the size and distribution, through the real-time control panel of the blank holder force can effectively control the flow of materials to achieve plate deformation degree of control over improve the sheet formability.
Forming a high dimensional accuracy (springback small) viscous media in forming the required pressure has good mobility, the forming process of complex shape parts can be realized entirely reasonable envelope, so that forming part of a good punch. Surface quality (keeping the original billets surface quality). Viscous forming part of the surface has a protective effect.
1.2 Semi-solid forming technology
Semi-solid forming technology that is in the material when in a semi-solid die forging. Semi-solid metal processing forming the main advantages: forming temperature is low (as compared with the cast) and the forming power is low (as compared with the forging), in a process, the more complex workpieces can be formed, its mechanical properties and relatively Forging . Semi-solid metal forming technology applicability, who has a solid-liquid two-phase region of alloys such as high temperature alloys, copper, aluminum and other semi-solid forming can be achieved.
For example, solid-state 2A50 alloy 450 ℃ thermal deformation flow stress 110MPa, 590 ℃ semi-solid when 9MPa, reduced 91%; AZ91D Alloy 300 ℃ solid-state thermal deformation flow stress 40MPa, 530 ℃ semi-solid when 7 MPa, lower 82%.
5000kN hydraulic press used successfully developed aluminum alloy road wheel armored semi-solid forming of local parts, composite materials locally enhanced technology to solve large-scale equipment, walking parts of light-weight alloy wear resistant partial key technologies. The use of a hot-forging equipment needed 30000KN tonnage.
1.3 Power Spinning Technology
Metal spinning through the rough rotation and combined effects of both external forces applied to metal slabs or pre-formed blank plastic deformation of the forming technology. Metal spinning is divided into ordinary and powerful spinning spinning. One is to reduce the tube-shaped pieces of strongly swirling Tube wall thickness, to improve their strength is an effective way.
1.4 Precision Forging billets effort and flow control technology
Using a local method of forming load and streaming, you can make less-deformable material in smaller loads, precise shape. Compared with the overall load partial load can be labor-saving multi-pass more than 70% can be resolved by adopting the triage forming the radial collateral side corner of the forming and a significant reduction in load.
1.5 hydroforming technology
Pressure device right through the closed mold cavity in a fluid-filled tube inside to put some pressure on the liquid inside has a very high pressure and flow, forcing the shape of the wall cavity space for inward flow forming, the maximum internal pressure can be achieved 4000 MPa. The technology features: (1) Due to the pressure medium flow so that it can change shape with the outside world, are applicable to any irregular shape in a shape, so that pipe structural strength increase; (2) in the process of filling will die cavity wall Jixiang forefront of the pressure medium to the shape of the envelope so that a continuous deformation of the wall, and because the parties to pass up the consistency of the internal pressure, so that parts throughout the produce uniform, continuous plastic deformation , degree of wall thinning consistent, easy to control the assembly size.
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