Cold heading is a non-cutting metal pressure processing technology that falls under the topic of metal pressure processing. Cold extrusion process is a key procedure in the manufacturing of fastening pieces. Cold extrusion is the best method for producing bolts, screws, nuts, and rivets.
What is Cold Extrusion
Cold heading is a critical component of precision plastic forming technique. Cold extrusion is the process of inserting a metal blank into a mold cavity while it is still cold. The metal material is forced to form plastic flow under the influence of high pressure and a specific speed in order to obtain the desired shape, size, and some extrusion parts with specific mechanical qualities.
Obviously, the purpose of cold extrusion processing is to control metal flow via molds, and a significant quantity of metal volume is transferred to produce parts. In fact, any fastener can be formed not only by cold heading, but also by a range of deformation methods like as extrusion, punching, and rolling.
Advantages Of Cold Extrusion
1. Reducing the use of raw materials.
Cold extrusion uses plastic deformation of metal to create the required parts, which reduces the cutting process and increases resource use. Cold extrusion materials can often be utilized at a rate of more than 80%.
2. Improve labor productivity
Manufacturing parts using a cold extrusion technique rather than a cutting process can enhance production several times, if not dozens of times.
3. The pieces have the perfect surface roughness and size precision.
Cold extruded parts rarely require re-cutting and only need to be ground for exceptionally high standards.
4. Improve part mechanical properties
The cold work hardening of metal through cold extrusion processing and a reasonable fiber streamline distribution inside the parts results in a substantially higher strength of the parts than the raw materials. Furthermore, a proper cold extrusion process can create compression stress on the surface of the pieces, increasing fatigue intensity. As a result, some components that require heat treatment enhancement can be saved by using the cold extrusion procedure.
5. Machinable parts with complicated shapes and difficult to cut processing.
Such as irregular section, complex inner cavity and teeth, and invisible inner grooves.
6.Reduce production cost
Because the cold extrusion process has the advantages of saving raw materials, increasing productivity, reducing the amount of cutting processing, and using inferior materials instead of high-quality materials, which can greatly reduce cost.
Difficulties In Application of Cold Extrusion Technology
1. High requirements for molds
When cold extruding, the deformation resistance of metal blank is significantly increased under the pressure stress in the mold, which makes the stress suffered much larger than the general stamping mold. In addition to high-intensity, the mold also needs sufficient impact toughness and high wear resistance.
2.A large tonnage press machine is required.
Because of the high deformation resistance of the blank during cold extrusion, press machines weighing hundreds or even thousands of tons are required.
3.Only applicable on a large production scale
Because of the high cost of cold extrusion molds, it is often only appropriate to the manufacture of large quantities of parts. The minimum quantity is 50000 pieces.
4. The surface treatment must be done ahead of time.
Surface treatment not only adds procedures and requires a big manufacturing area, but it is also difficult to automate.
5.Inappropriate for high-intensity material processing
6. Part deformation and corrosion resistance reduce
The plasticity and impact toughness of cold extruded parts have become worse, and the residual stress of the parts is large, which will cause parts deformation and produce stress corrosion.
Development Trend of Cold Extrusion Technology
1.As the energy crisis worsens, people will pay more attention to environmental quality, and increased market rivalry will encourage the growth of forging production in the direction of efficiency, high quality, refinement, energy savings, and material savings. As a result, the production of refined forging parts produced by extruding forming and other techniques will compete in the market.
2.The car has evolved in the directions of lightness, fast speed, and stability. Higher requirements for size precision, weight accuracy, and mechanical qualities of forging parts have been proposed, which will encourage the development of refined production technology.
3. Cold extrusion production is still evolving toward specialized and large-scale organizational production.
4. Extrusion machines will become a trend in the future. The refined production development of small and medium-sized forging parts, as well as the application of cold extrusion technology, will drive the development of multi station cold extrusion machines, precision presses, and unique machines designed and constructed for some forged parts.
Summary
Cold extrusion technology is a high-precision, high-efficiency, high-quality, and low-consumption manufacturing technique that is typically used in large-scale production of fastening parts.
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