DOUBLE-ACTION PIERCING INDIRECT EXTRUSION PRESS

When the extrusion machine performs indirect extrusion, the direction of metal outflow is opposite to the direction of the extrusion stem’s forward movement (relatively speaking), and there is no relative motion between the extrusion container and the billet.

The schematic diagram of indirect extrusion of material is shown in the above figure. The part that originally installed the extrusion stem has been modified into a blocking plate 1, which seals a section of the inner lining 2 of the extrusion cylinder; The original mold seat was equipped with a stationary hollow extrusion stem 4, and a mold 3 was installed at the head of the extrusion stem. When the main plunger is pushed in the direction of the arrow, the extrusion cylinder moves together with the billet, forcing the metal billet to flow out of the hole in mold 3, forming extruded product 5.

The process characteristics and advantages of efficient indirect extrusion .  In the process of efficient indirect extrusion, due to the formation of advanced circular flow in the extrusion cylinder and the supplementary compression of metal flow near the mold, the hydrostatic pressure of the fluid is increased, the leading edge of the metal flow is leveled, and the unevenness of deformation is eliminated. Therefore, regardless of whether compared with forward extrusion (in terms of energy consumption, uniformity of organization, dimensional accuracy and yield in the length direction of the profile), or compared with indirect extrusion (in terms of life characteristics, uniformity of mechanical properties, dimensional accuracy and surface quality of the profile cross-section), efficient indirect extrusion has obvious advantages: ① Can increase the outflow velocity of metal. Under similar conditions, when using non lubricated high-efficiency indirect extrusion, indirect extrusion, and forward extrusion to extrude 2024 alloy with a diameter of 60mm, the proportion of maximum metal flow velocity is (2.9 ± 0).2) (1.7 ± 1): 1.O. It can be seen that efficient indirect extrusion can greatly improve production efficiency; ② When using efficient indirect extrusion, due to the acceleration of peripheral flow and the deceleration of central flow in the extruded billet, the surface quality of the extruded product is good, the microstructure is uniform, and the mechanical properties are stable; ③ When using efficient indirect extrusion, the height of the extruded residue is reduced by 50%, the depth of the coarse crystal ring at the end of the extruded product is reduced to 1mm, and there are generally no bubbles, scars, or scratches on the surface of the product. There are no phenomena such as overburning, cracks, or shrinkage, and the yield can reach 89%.5%, up to a maximum of 92%; ④ It can greatly increase the plasticity of metals and enable alloys that are extremely difficult to extrude and deform (such as powder alloys and particle alloys) to achieve high squeezability, thereby obtaining various complex extruded products; ⑤ It can achieve semi continuous and pseudo isotropic flow, greatly improving and stabilizing the dimensional accuracy of products, and eliminating the anisotropy of extruded product performance. For example,  the anisotropy of σ b in bars extruded from A1+8% Ce alloy particles can be reduced from 35% -45% in forward extrusion to 1% -3%;The maximum strength of the 2040 alloy large material center can reach over 85% of the peak strength;It can increase the Kic of 2024 alloy large materials by 20% and improve the peel corrosion resistance by 35% -40%; ⑥ It can form a production line for hard  alloy profiles with good stability and product quality. The application of high-efficiency indirect extrusion  has developed various types of new extruders based on the basic principles of high-efficiency indirect extrusion. Table 1 lists the structure and extrusion process parameters of 5MN and 25MN high-efficiency indirect extruders.

A complete set of efficient indirect extrusion tools has been developed based on the variety, specifications, and uses of  alloy products, mainly including a complete extrusion pad with a circular hole;2-3 extrusion pads with forming grooves;Combination extrusion cushion block with multiple groove cross-sections.The compression pad consists of several working pads and a steel sleeve connected in a circular shape with steel pipes for assembling the working pads.The steel sleeve accurately fixes and installs these work pads, and the extrusion pads can be removed from the outside of the extruder.There are two types of extrusion molds: detachable and fixed (with elastic components). Changing from integral extrusion pads to composite extrusion pads can increase the outer diameter of single hole and porous extrusion profiles by 25% -30%.A complete set of extrusion pads can be suitable for the production of various types and specifications of profiles.

Toolings for piercing indirect extrusion press

piercing system

1.Cooling fixed head
2.nut
3.bracket
4.ring
5.piercing rod
6.cooling tube
7.bearing

Indirect Extrusion container

container tire:5CrMnMo
2.Liner:H13 Steel
3.container key
4.Hex socket bolt

Indirect Extrusion stem

1. stem:H13 steel
2.dummy block:H13 steel
3. clean out disc: H13 steel
4. Dummy block:H13 steel