The definition of cold extrusion: Extrusion at a temperature lower than the recovery temperature. For most non-ferrous metals such as aluminum, copper, titanium, steel, etc., it generally refers to extrusion at room temperature.
Cold extrusion is a process in which a metal blank is placed in a cold extrusion cavity, and pressure is applied to the blank through a pressure-fixed punch at room temperature to plastically deform the metal blank, thereby forming a part processing method.
At present, my country can cold extrude metals such as lead, tin, aluminum, copper, zinc and their alloys, low-carbon steel, medium-carbon steel, tool steel, low-alloy steel, and stainless steel. Even bearing steel, high-carbon and high-aluminum alloy tool steel, high-speed steel, etc. can be cold extruded with a certain amount of deformation. In terms of extruders, China has the ability to design and manufacture extruders of various tonnages. In addition to using general mechanical presses, hydraulic presses and cold extrusion presses, we have also successfully used friction presses and cold presses equipped with high-speed, high-energy equipment.
Chinese suppliers provide American RP series radial cold extrusion presses for cold extrusion of involute or rectangular splines and profile parts. Suitable for cold forming equipment for auto parts.
1. Process principle
Kineflow warp yarn cold extrusion process:
The radially arranged molds are pressed against the central workpiece by a set of deformation power actuators. The mold is fed radially, and this operation is performed by a shaft hydraulic cylinder that pushes a ring with a wedge-shaped surface. This converts axial displacement and force into radial displacement and force.
2. Processing ability
In addition to the size of the extrusion force depends on the elongation of the material, it also depends on the number of teeth on the workpiece, the depth of the teeth, the shape of the tooth surface and the forming length. Most tooth shapes can be extruded, as long as the side of the tooth does not prevent the tooth from being pulled out of the mold after the workpiece is formed. The side surface of the formed tooth can be straight, involute or other complicated spherical convex shape, the formed side surface and the tooth root can have no sharp corners, and the tooth surfaces are opposite.
3. Molding characteristics
Pitch and tooth tolerance are the main post-forming parameters. Correct control of the blank can provide very high stability accuracy. Unlike the shaft compression that controls the outer diameter, the tip is extruded radially and has a flange. This is because there is no restriction on the axial flow of the material during the molding process.
4. Material requirements
Generally, the hardness of the material is higher than HRC25, and the elongation is at least 15% to improve the life of the mold. In addition, the smaller the pressure angle, the greater the load on the mold, which affects the life of the mold and the cumulative error of the pitch.
5. Equipment construction
The device has horizontal and vertical junctions. The mold disassembly and assembly are modularized, which is convenient and quick. It can be loaded or unloaded manually, or fully automated. The hydraulic system can be placed separately inside the fuselage or outside the fuselage.
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