A lateral extrusion pre-forging die, a finish-forging die and a forging system

Abstract

This invention relates to the field of closed-die forging, specifically to a lateral extrusion pre-forging die, a final forging die, and a forging system. The lateral extrusion pre-forging die includes: an upper pre-forging die and a lower pre-forging die that move along the die-closing direction, and an extrusion hammer that moves perpendicular to that direction. These three components together define a pre-forging cavity. The pre-forging cavity includes a feeding channel and radial channels. The feeding channel is collinear with the extrusion direction of the extrusion hammer and is occupied by the extrusion hammer when the die is closed. The radial channels extend radially from the end of the feeding channel as the center, branching out into multiple channels. This invention uses a lateral extrusion hammer to extrude hot billets within a closed pre-forging cavity, allowing them to flow within the closed radial channels. This results in less flash, reducing material waste, and requires lower extrusion forming force, thus reducing production costs.

Description

Technical Field

[0001] This invention relates to the field of closed-die forging, and more specifically to a lateral extrusion pre-forging die.

[0002] The present invention also relates to a final forging die.

[0003] The present invention also relates to a forging system. Background Technology

[0004] Steering knuckles are typically L-shaped, characterized by the use of more material in the bend and stem, less material in the side branches, and an included angle close to 90°. The cross-section of such parts changes drastically and the material distribution is uneven. Currently, the main forming methods for steering knuckles in the industry include casting and traditional die forging, but both of these processes have significant drawbacks.

[0005] Casting can easily form complex L-shaped or asymmetrical structures, but the cooling and shrinkage characteristics of casting can easily lead to micro-defects such as shrinkage cavities and porosity inside the casting. These defects seriously disrupt the continuity of the material, resulting in the mechanical properties, fatigue life and reliability of the formed parts being far lower than those of forgings, making it difficult to meet the stringent requirements of heavy-duty engineering machinery.

[0006] Die forging typically employs open die forging or multi-pass closed die forging. Due to the uneven material distribution in L-shaped parts, the metal flow resistance is high during the traditional upper and lower die forging process, which easily leads to defects such as folding and incomplete filling. To ensure that the cavity is filled, traditional processes often require the addition of a large amount of flash to force the metal to fill each flow channel branch, resulting in extremely low material utilization (usually only about 43%), and large subsequent machining allowances and high costs. At the same time, traditional die forging applies pressure over the entire projected area of ​​the part, requiring extremely high forming force, often necessitating large forging equipment with a capacity of over 16,000 kN, which greatly increases equipment investment and production energy consumption. Summary of the Invention

[0007] The purpose of this invention is to provide a lateral extrusion pre-forging die, a final forging die, and a forging system, which are designed to produce steering knuckles with low energy consumption and high material utilization.

[0008] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A lateral extrusion pre-forging die includes: an upper pre-forging die and a lower pre-forging die, which are disposed on a die frame and are capable of relative movement in the die closing direction; The extrusion hammer is mounted on the mold frame and can move in a direction perpendicular to the mold closing direction. When the upper pre-forging mold, the lower pre-forging mold, and the extrusion hammer are all in the mold closing state, they together define a pre-forging cavity. The pre-forging cavity includes a feeding channel, which takes the shape of a cylindrical hole when the upper pre-forging die and the lower pre-forging die are closed, and is occupied by the extrusion hammer when the extrusion hammer is closed. The axis of the feeding channel is collinear with the extrusion direction of the extrusion hammer. The radial flow channel extends radially from the end of the feeding channel as the geometric center to form multiple flow channel branches, and the flow channel branches have a preset angle with the axis of the feeding channel.

[0009] Furthermore, the flow channel branch includes: at least one main branch flow channel, located in a first plane where the axis of the feeding flow channel is located, and having a first angle with the axis of the feeding flow channel; At least one side channel is located in a second plane containing the axis of the feeding channel and has a second included angle with the axis of the feeding channel; The first plane and the second plane are perpendicular to each other.

[0010] Furthermore, there are two main branch channels, and the two main branch channels extend in opposite directions to each other; The number of side channel is two, and the two side channel and the feeding channel are located in the same plane.

[0011] Furthermore, the axis of each main branch flow channel is parallel to the mold closing direction, and the axis of each side branch flow channel and the axis of the feeding flow channel are located on the parting surface of the pre-forging upper mold and the pre-forging lower mold.

[0012] Furthermore, the parting surface of the pre-forging upper die is provided with a groove formed around the edge of the pre-forging cavity; The parting surface of the pre-forging lower die is provided with a flange formed around the edge of the pre-forging cavity; The flange engages with the groove to restrict the relative movement of the upper pre-forging die and the lower pre-forging die along a direction perpendicular to the die closing direction.

[0013] Furthermore, the cross-section of the feeding channel and each of the channel branches is circular or elliptical, and the extrusion hammer is fitted with the feeding channel with a clearance.

[0014] Furthermore, the upper pre-forging die and the lower pre-forging die together form a flush lateral bearing surface on the side opposite to the feeding channel.

[0015] A final forging die is used to perform final forging on a pre-forged billet forged by a lateral extrusion pre-forging die. It includes an upper final forging die and a lower final forging die, which are disposed on a die set and can move relative to each other in the die closing direction. When the upper final forging die and the lower final forging die are in the die closing state, they jointly define a final forging cavity. The internal contour of the final forging cavity is adapted to the final shape of the pre-forged billet after final forging.

[0016] Furthermore, the final forging cavity includes: at least one main branch cavity, the main branch cavity including a frustum-shaped inner wall extending along the mold closing direction, and a circular boss coaxially formed at the bottom of the main branch cavity, such that a cylindrical gap is formed between the outer peripheral wall of the circular boss and the frustum-shaped inner wall of the main branch cavity. The first side branch cavity includes a stepped axial inner wall with a gradually changing diameter extending in a direction perpendicular to the mold closing direction. The second side branch cavity includes a flat, rib-shaped inner wall extending in a direction perpendicular to the mold closing direction.

[0017] A forging system includes a lateral extrusion pre-forging die and a final forging die, as well as a multi-directional forging press; The multi-directional forging press includes: a worktable for placing the pre-forging lower die and the final forging lower die; The first driver has an actuator that moves linearly along the mold closing direction, for driving the pre-forging upper die and the final forging upper die; The second driver has an actuator that moves linearly in a direction perpendicular to the mold closing direction, for driving the extrusion hammer to move along the feed channel; The third driver has an actuator that moves in the opposite direction to the second driver, and is used to drive the balancing pressure head to apply a balancing force to the upper and lower pre-forging dies to counteract the extrusion force output by the extrusion hammer.

[0018] The advantages of this invention compared to the prior art are: This invention defines a closed pre-forging cavity by using a closed pre-forging upper die and a closed pre-forging lower die. A lateral extrusion hammer pushes the hot billet to flow in a closed radial flow channel. On the one hand, it produces less flash, thereby reducing material waste. On the other hand, it requires a low extrusion forming force, thereby reducing production costs. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of the pre-forging die according to an embodiment of the present invention; Figure 2 This is a top view of the pre-forging upper die according to an embodiment of the present invention; Figure 3 This is a perspective view of the pre-forging upper die according to an embodiment of the present invention; Figure 4 This is a top view of the pre-forging lower die according to an embodiment of the present invention; Figure 5 This is a perspective view of the pre-forging lower die according to an embodiment of the present invention; Figure 6 This is a top view of the final forging die according to an embodiment of the present invention; Figure 7 This is a perspective view of the final forging die according to an embodiment of the present invention; Figure 8 This is a top view of the final forging die according to an embodiment of the present invention; Figure 9 This is a perspective view of the final forging die according to an embodiment of the present invention; Figure 10 This is a front view of the multi-directional forging press according to an embodiment of the present invention; Figure 11 This is a perspective view of a 6110A aluminum alloy steering knuckle for forklifts according to an embodiment of the present invention; The labels in the diagram represent the following: 11-Pre-forging upper die; 12-Pre-forging lower die; 13-Extrusion hammer; 14-Pre-forging cavity; 141-Feeding channel; 142-Radial channel; 143-Main branch channel; 144-Side branch channel; 145-Flange; 146-Groove; 15-Lateral bearing surface; 16-Balancing head; 21-Upper die for final forging; 22-Lower die for final forging; 23-Cavity for final forging; 231-Main branch cavity; 232-Circular boss; 233-Cylindrical gap; 234-First side branch cavity; 235-Second side branch cavity; 236-Exhaust hole; 237-Flash groove; 238-Overflow groove; 31-Workbench; 32-First driver; 33-Second driver; 34-Third driver. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 This embodiment provides a lateral extrusion pre-forging die, which includes an upper pre-forging die 11, a lower pre-forging die 12, and an extrusion hammer 13. The upper pre-forging die 11 and the lower pre-forging die 12 are disposed on a die frame and can move relative to each other in the die-closing direction. The extrusion hammer 13 is also disposed on a die frame and can move in a direction perpendicular to the die-closing direction. When the upper pre-forging die 11, the lower pre-forging die 12, and the extrusion hammer 13 are all in the die-closing state, the three together define a pre-forging cavity 14.

[0023] Specifically, the pre-forging cavity 14 includes a feeding channel 141 and a radial channel 142. When the upper pre-forging die 11 and the lower pre-forging die 12 are closed, the feeding channel 141 takes the shape of a cylindrical hole. When the extrusion hammer 13 is closed, the feeding channel 141 is occupied by the extrusion hammer 13, and the axis of the feeding channel 141 is collinear with the extrusion direction of the extrusion hammer 13. The radial channel 142 extends radially from the end of the feeding channel 141 as the geometric center to form multiple channel branches, and each channel branch has a preset angle with the axis of the feeding channel 141.

[0024] Furthermore, in order to achieve the forming of forgings with specific complex shapes, the radial flow channels 142 include at least one main branch flow channel 143 and at least one side branch flow channel 144.

[0025] The main branch channel 143 is located in the first plane containing the axis of the feeding channel 141 and has a first angle with the axis of the feeding channel 141; the side branch channel 144 is located in the second plane containing the axis of the feeding channel 141 and has a second angle with the axis of the feeding channel 141; the first plane and the second plane are perpendicular to each other.

[0026] In this embodiment, the first included angle is set to 90° and the second included angle is set to 120°, thereby forming a shape that approximates the forklift steering knuckle.

[0027] Furthermore, the number of main branch channels 143 is set to two, and the extension directions of the two main branch channels 143 are opposite to each other; at the same time, the number of side branch channels 144 is also two, and the two side branch channels 144 and the feeding channel 141 are located in the same plane; in the actual pre-forging process, the main branch channels 143 are used to guide the metal material to form a cylindrical shape, while the side branch channels 144 are used to guide the metal material to extend to both sides to form two branch structures.

[0028] Furthermore, in order to ensure smooth demolding and reasonable parting, the axis of each main branch flow channel 143 is parallel to the mold closing direction, while the axis of each side branch flow channel 144 and the axis of the feeding flow channel 141 are located on the parting surface of the pre-forging upper die 11 and the pre-forging lower die 12.

[0029] Furthermore, to improve the closing accuracy and resistance to lateral forces of the mold, a groove 146 is provided on the parting surface of the pre-forging upper mold 11, forming a groove around the edge of the pre-forging cavity 14; correspondingly, a flange 145 is provided on the parting surface of the pre-forging lower mold 12, forming a flange around the edge of the pre-forging cavity 14, and the flange 145 and the groove 146 are engaged in a plug-in fit; after the pre-forging upper mold 11 and the pre-forging lower mold 12 are closed, the plug-in fit between the flange 145 and the groove 146 can effectively prevent the pre-forging upper mold 11 and the pre-forging lower mold 12 from undergoing slight movement or misalignment along the direction perpendicular to the mold closing direction (i.e., the direction of lateral force), thus ensuring the dimensional accuracy of the pre-forged billet.

[0030] Furthermore, in this embodiment, the initial bar stock used before pre-forging is cylindrical. In order to make the metal flow smoother and reduce deformation resistance, the cross-section of the feed channel 141 and each channel branch is designed to be circular or elliptical. Therefore, each main branch and side branch of the formed pre-forged billet presents a cylindrical or frustum shape.

[0031] Furthermore, in the design of the mold fitting clearance, the extrusion hammer 13 and the feeding channel 141 adopt a precise clearance fit; in the pre-forging process of high fluidity materials such as aluminum alloy, the gap between the extrusion hammer 13 and the feeding channel 141 is strictly controlled, so that only a very small amount of material overflows to form a tiny flash to release overpressure, and the tiny flash can be easily removed after demolding.

[0032] Furthermore, the pre-forging upper die 11 and the pre-forging lower die 12 together form a flat lateral bearing surface 15 on the side opposite to the feeding channel 141; in the closed state, the lateral bearing surface 15 is used to fit with the balance pressure head of the multi-directional forging press to withstand the lateral force generated during the extrusion process.

[0033] Furthermore, in order to meet the hot forging temperature requirements of specific materials such as aluminum alloys, the interior of the pre-forging upper die 11, the pre-forging lower die 12, and the extrusion hammer 13 are all provided with heating channels or resistance heating holes, so as to preheat the pre-forging upper die 11, the pre-forging lower die 12, and the extrusion hammer 13 and maintain them within the preset working temperature range.

[0034] Further, refer to Figure 6 , Figure 7 , Figure 8 and Figure 9 This embodiment also provides a final forging die for final forging of the pre-forged billet forged by the above-mentioned lateral extrusion pre-forging die.

[0035] The final forging die includes an upper final forging die 21 and a lower final forging die 22, which are mounted on a die frame and can move relative to each other in the die closing direction. When the upper final forging die 21 and the lower final forging die 22 are in the closed state, they jointly define a final forging cavity 23. The final forging cavity 23 includes a main branch cavity 231, a first side branch cavity 234 and a second side branch cavity 235 that are radially distributed around a geometric center.

[0036] The main branch cavity 231 includes a frustum-shaped inner wall extending along the mold closing direction, and a circular boss 232 coaxially formed at the bottom of the main branch cavity 231, such that a cylindrical gap 233 is formed between the outer peripheral wall of the circular boss 232 and the frustum-shaped inner wall of the main branch cavity 231.

[0037] The first side branch cavity 234 has a stepped axial inner wall with a gradually changing diameter extending in a direction perpendicular to the mold closing direction; the second side branch cavity 235 includes a flat, rib-shaped inner wall extending in a direction perpendicular to the mold closing direction.

[0038] Further, refer to Figure 10 This embodiment also provides a forging system, which includes the aforementioned lateral extrusion pre-forging die, final forging die, and multi-directional forging press.

[0039] The multi-directional forging press is a three-directional press, which includes a worktable 31 and three hydraulic cylinders. The three hydraulic cylinders are: a first driver 32 arranged longitudinally, and a second driver 33 and a third driver 34 arranged laterally.

[0040] The first driver 32 is used to drive the pre-forging upper die 11 to move downward and close the die; the second driver 33 drives the extrusion hammer 13 to perform lateral extrusion; the third driver 34 drives the balancing pressure head 16 to perform lateral extrusion on the opposite side of the extrusion hammer 13, thereby providing lateral support force to balance the extrusion force and prevent the die from lateral slippage.

[0041] Furthermore, in order to ensure the quality of the final forging and avoid product defects caused by poor metal flow or gas trapping, the final forging die also includes a flash groove 237 and an overflow groove 238; wherein, the flash groove 237 is provided at the edge of the parting surface of the final forging cavity 23, and the overflow groove 238 is provided at the outer edge of the flash groove 237.

[0042] During the final forging and die closing process, the flash groove 237 is used to accommodate excess metal material and increases the resistance to the metal flowing out of the cavity through its narrow bridge, thereby forcing the metal material to fill the various complex branches of the cavity under high internal pressure.

[0043] The overflow groove 238 is used to receive excess metal that continues to overflow from the flash groove 237, effectively preventing excessively thick flash from being generated at the parting surface of the mold, thereby ensuring the mold closing accuracy of the final forging upper mold 21 and the final forging lower mold 22, and reducing the difficulty of subsequent edge trimming processes.

[0044] Furthermore, since the cylindrical gap 233 in the main branch cavity 231 is relatively deep, in order to prevent air resistance, multiple vent holes 236 are provided at the bottom of the cylindrical gap 233, and the multiple vent holes 236 are evenly distributed around the center of the cylindrical gap 233. During the process of the high-temperature metal billet being rapidly extruded and filling the cylindrical gap 233, the air in the cylindrical gap 233 and the gas generated by the volatilization of the mold lubricant can be quickly discharged outside the mold through these evenly distributed vent holes 236, thereby avoiding defects such as porosity, local depressions or incomplete filling in the final forging part.

[0045] refer to Figure 11 Taking the production of 6110A aluminum alloy steering knuckles for forklifts as an example, the specific implementation steps of the forging method are as follows: Step 1: Use 6110A hot-extruded aluminum alloy bar with a diameter of 75mm, saw it into a cylindrical initial billet weighing 2.94kg, and use a chain heating furnace to uniformly heat the billet to 520℃±5℃ to obtain a hot billet.

[0046] Step 2: Using the heating channels and temperature control system inside the mold, the upper pre-forging mold 11 and the lower pre-forging mold 12 are preheated and kept constant at 200℃±10℃, and the extrusion hammer 13 is preheated and kept constant at 250℃±10℃; at the same time, water-based graphite lubricant is uniformly sprayed on the surface of the pre-forging cavity 14 and inside each flow channel branch.

[0047] Step 3: The heated billet is quickly placed into the feeding channel 141 of the pre-forging lower die 12 within 20 seconds; then, the three-way press is started, and its first driver 32 drives the pre-forging upper die 11 downward, applying a constant clamping force of about 300 tons to tightly close with the pre-forging lower die 12; at this time, the clamping force is sufficient to overcome the normal separation force brought about by the subsequent transverse extrusion, and a pre-forging cavity 14 is established around the hot billet.

[0048] Step four: Under the constraint of maintaining a constant longitudinal clamping force of 300 tons, the second driver 33 of the triaxial press drives the extrusion hammer 13 to advance horizontally at a speed of 50 mm / s, applying an extrusion force of about 150 tons to the hot billet; simultaneously, the third driver 34 on the opposite side drives the balancing pressure head 16 to press against the lateral bearing surface 15 of the die, providing 150 tons of lateral support force to balance the extrusion load; under the strong triaxial compressive stress and cavity geometric constraints, the aluminum alloy material undergoes plastic diversion along the respective set angles to the main branch flow channel 143 and the side branch flow channel 144 until it fills the pre-forged cavity 14.

[0049] Step 5: Hold pressure for 0.8 seconds to allow the aluminum alloy material to fully absorb the deformation heat and stabilize the profile; then, the second actuator 33 and the third actuator 34 first release pressure and retract, the first actuator 32 releases pressure and lifts the pre-forging upper die 11, and the operator or robotic arm takes out the obtained pre-forging billet.

[0050] Step six: The pre-forged billet is quickly transferred to the final forging die on the same workbench 31; under the closed extrusion of the final forging die, the pre-forged billet undergoes final plastic deformation, and the excess material is squeezed into the flash groove 237 and overflow groove 238. The gas in the final forging cavity is discharged through the exhaust hole 236 at the bottom of the cylindrical gap 233, and finally a steering knuckle finished product with less flash, continuous internal metal flow lines, and high dimensional accuracy is obtained.

[0051] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A lateral extrusion pre-forging die, characterized in that, include: The upper pre-forging die (11) and the lower pre-forging die (12) are mounted on the die frame and can move relative to each other in the die closing direction; The extrusion hammer (13) is mounted on the mold frame and can move in a direction perpendicular to the mold closing direction. When the pre-forging upper mold (11), the pre-forging lower mold (12) and the extrusion hammer (13) are all in the mold closing state, they jointly define a pre-forging cavity (14). The pre-forged cavity (14) includes: The feeding channel (141) takes the shape of a cylindrical hole when the pre-forging upper die (11) and the pre-forging lower die (12) are closed. When the extrusion hammer (13) is closed, it is occupied by the extrusion hammer (13). The axis of the feeding channel (141) is collinear with the extrusion direction of the extrusion hammer (13). The radial flow channel (142) extends radially from the end of the feeding flow channel (141) to form multiple flow channel branches, and the flow channel branches have a preset angle with the axis of the feeding flow channel (141).

2. The lateral extrusion pre-forging die according to claim 1, characterized in that, The flow channel branch includes: At least one main branch channel (143) is located in a first plane containing the axis of the feeding channel (141) and has a first angle with the axis of the feeding channel (141); At least one side channel (144) is located in a second plane containing the axis of the feeding channel (141) and has a second included angle with the axis of the feeding channel (141); The first plane and the second plane are perpendicular to each other.

3. The lateral extrusion pre-forging die according to claim 2, characterized in that, The number of the main branch channels (143) is two, and the two main branch channels (143) extend in opposite directions to each other; The number of side channel (144) is two, and the two side channel (144) and the feeding channel (141) are located in the same plane.

4. The lateral extrusion pre-forging die according to claim 3, characterized in that, The axis of each main branch flow channel (143) is parallel to the mold closing direction, and the axis of each side branch flow channel (144) and the axis of the feeding flow channel (141) are located on the parting surface of the pre-forging upper mold (11) and the pre-forging lower mold (12).

5. The lateral extrusion pre-forging die according to claim 4, characterized in that, The pre-forging upper die (11) has a groove (146) formed around the edge of the pre-forging cavity (14) on its parting surface. The pre-forging lower die (12) is provided with a flange (145) formed around the edge of the pre-forging cavity (14) on the parting surface. The flange (145) is inserted into the groove (146) to restrict the relative movement of the pre-forging upper die (11) and the pre-forging lower die (12) in a direction perpendicular to the die closing direction.

6. The lateral extrusion pre-forging die according to claim 1, characterized in that, The cross-section of the feeding channel (141) and each of the channel branches is circular or elliptical, and the extrusion hammer (13) is clearance-fitted with the feeding channel (141).

7. The lateral extrusion pre-forging die according to claim 1, characterized in that, The upper pre-forging die (11) and the lower pre-forging die (12) together form a flat lateral bearing surface (15) on the side away from the feeding channel (141).

8. A final forging die for final forging of a pre-forged billet forged by a lateral extrusion pre-forging die according to any one of claims 1-7, characterized in that, It includes a final forging upper die (21) and a final forging lower die (22), which are set on the die frame and can move relative to each other in the die closing direction. When the final forging upper die (21) and the final forging lower die (22) are in the die closing state, they jointly define a final forging cavity (23). The internal contour of the final forging cavity (23) is adapted to the final shape of the pre-forged billet after final forging.

9. The final forging die according to claim 8, characterized in that, The final forging cavity (23) includes: At least one main branch cavity (231) includes a frustum-shaped inner wall extending along the mold closing direction and a circular boss (232) coaxially formed at the bottom of the main branch cavity (231) such that a cylindrical gap (233) is formed between the outer peripheral wall of the circular boss (232) and the frustum-shaped inner wall of the main branch cavity (231). The first side branch cavity (234) includes a stepped axial inner wall with a gradually changing diameter extending in a direction perpendicular to the mold closing direction; The second side branch cavity (235) includes a flat, rib-shaped inner wall extending in a direction perpendicular to the mold closing direction.

10. A forging system comprising the lateral extrusion pre-forging die of claim 1 and the final forging die of claim 8, and a multi-directional forging press; The multi-directional forging press includes: A workbench (31) is used to place the pre-forging lower die (12) and the final forging lower die (22). The first driver (32) has an actuator that moves linearly along the mold closing direction for driving the pre-forging upper mold (11) and the final forging upper mold (21). The second driver (33) has an actuator that moves linearly in a direction perpendicular to the mold closing direction, for driving the extrusion hammer (13) to move along the feeding channel (141); The third driver (34) has an actuator that moves in the opposite direction to the second driver (33) and is used to drive the balancing pressure head (16) to apply a balancing force to the pre-forging upper die (11) and the pre-forging lower die (12) to counteract the extrusion force output by the extrusion hammer (13).

Images