A thick plate multi-directional forging deformation preparation process method and die device

Abstract

The present invention discloses a multi-directional forging deformation preparation process method for thick plates and a die device, which belongs to the field of large plastic deformation process of alloys. The device includes: a left die, a right die, a horizontal cylinder, a vertical punch, and a horizontal punch. During stamping, the vertical punch slides down along the inclined curved surface cavity of the horizontal cylinder. The offset of the vertical punch in the horizontal direction can be obtained by the angle of the horizontal cylinder cavity, and then transmitted to the blank by the horizontal punch. The present invention effectively improves the material utilization rate of forging forming and makes the forging as close as possible to the shape and size of the finished parts. The small cavity angle can make a smaller vertical pressure obtain a larger horizontal pressure, which reduces the number of steps compared with ordinary die forging, improves production efficiency, and reduces energy consumption. In addition, the nano-scale precipitates and high-density defects introduced by the multi-directional forging process make the forgings have good strength-shaping synergy, and the forging performance is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of material preparation, and in particular relates to a thick plate multi-directional forging deformation preparation process method and a die device. Background Art

[0002] The multi-directional forging (MDF) process is a severe plastic deformation (SPD) process that has developed rapidly in recent years. This method applies small strain compression deformation to the sample in different directions in turn. After multiple forging passes, a large cumulative strain is obtained, which promotes the refinement of the organization and structure and achieves a synergistic improvement in the strength and plasticity of the sample. However, the multi-directional forging process is only for block materials, and the sample size is small. For plate materials, since compression deformation along the plate surface direction can easily cause buckling and it is difficult to achieve a certain degree of compression, the multi-directional forging process cannot be implemented. At present, thick plate profiles prepared by extrusion / rolling process are mostly used for ordinary structural materials. If the multi-directional forging process is applied to thick plate materials, it will greatly improve the mechanical properties of the material and expand the application space of thick plate profiles. Summary of the Invention

[0003] In response to the above-mentioned problems existing in the existing multi-directional forging process for large-sized thick plate samples, the present invention proposes a thick plate multi-directional forging deformation preparation process method and die device. The technical solution adopted by the present invention is:

[0004] A thick plate multi-directional forging deformation preparation die device, the device comprising: a left die 2, a right die 3, a horizontal cylinder 1, a horizontal pressing head 4, and a vertical pressing head 5;

[0005] The horizontal cylinder 1 has an inclined curved cavity. The left mold 2 and the right mold 3 are fixed in the inclined curved cavity of the horizontal cylinder 1 after being combined, and are aligned with the height of the horizontal cylinder 1. One end of the left mold 2 and the right mold 3 is respectively provided with a connecting end. When combined, the side surface formed by the connecting end serves as the extrusion cavity surface, and the cavity enclosed by the other end and the horizontal cylinder 1 serves as the extrusion cavity. The outer curved surfaces of the left mold 2 and the right mold 3 each have an angle θ with the vertical direction, which is equal to the angle θ between the inner inclined curved surface of the horizontal cylinder 1 cavity and the vertical direction.

[0006] The horizontal ram 4 is placed in the cavity between the left die 2 and the right die 3. One side serves as the extrusion cavity surface, and the other side of the horizontal cylinder 1 cavity wall forms a gap for installing the vertical ram 5. The contact surface between the vertical ram 5 and the horizontal cylinder 1 cavity wall is also set at an angle θ with the vertical direction, so that when the vertical ram 5 moves downward under the pressure of the press, it will form a horizontal extrusion on the blank in the cavity through the horizontal ram 4 or directly;

[0007] Among them, the angle θ between the inner inclined surface of the horizontal cylinder 1 cavity, the vertical pressure head 5, the outer curved surfaces of the left mold 2 and the right mold 3 and the vertical direction can be selected to be between 3° and 7°, and the vertical pressure head 5 is higher than the top surface of the horizontal cylinder 1.

[0008] The horizontal cylinder 1 is provided with a groove for guidance, which allows one end of the extrusion cavity of the left die 2 and the right die 3 to slide downward along the groove of the horizontal cylinder 1 to connect. This ensures that the horizontal cylinder 1, the left die 2, and the right die 3 are all fixed and do not move during the forging process. In addition, the vertical ram 5 is embedded in the groove of the cavity of the horizontal cylinder 1 to limit the vertical ram 5.

[0009] Preferably, the composition of the left mold 2 and the right mold 3 is Cr with high strength. 12 MoV steel, the horizontal pressure head 4 and the vertical pressure head 5 use 45 steel, and the good wear resistance makes the pressure head mold have a long service life.

[0010] A thick plate multi-directional forging deformation preparation process method, the specific steps are:

[0011] 1) First mark the material thickness direction as X, and the other two orthogonal directions as Y and Z, and then start forging. The forging process can be carried out at room temperature or under heating;

[0012] 2) First, perform a forging in the X direction. Place the vertical ram 5 in the groove of the horizontal cylinder 1. Then, place the left die 2 and the right die 3 in the horizontal cylinder 1 along the edge of the vertical ram 5, so that the contact surfaces of the left die 2 and the right die 3 are in contact.

[0013] 3) Remove the vertical pressing head 5 from the mold, place the lubricated billet into the extrusion cavity and fit it to the surface of the mold cavity, then insert the horizontal pressing head 4 to press the billet;

[0014] 4) Place the vertical pressure head 5 in the groove and perform a punching test. The punch of the press moves downward at a rate v, and the displacement s of the vertical pressure head 5 is obtained according to the corresponding time t, thereby calculating the horizontal compression displacement of the blank. The calculation formula is as follows:

[0015] Δl=s×tanθ=vt×tanθ

[0016] At this time, the calculation formula of the horizontal compressive stress σ of the blank is as follows:

[0017]

[0018] The calculation formula of the strain of the blank in the horizontal direction is as follows:

[0019]

[0020] According to the law of volume invariance, the strain calculation formula in the vertical direction is as follows:

[0021]

[0022] Where N is the load provided by the press, A is the area of ​​the pressing surface, l is the length of the blank in the vertical direction between the blank and the horizontal punch, h is the height of the blank forged along the X direction, and θ is the inclination angle of the inner wall of the horizontal cylinder;

[0023] 5) After the X-direction forging is completed, follow the method of steps 2) to 4) and forge the Y-direction at the same compression rate;

[0024] 6) After forging in the Y direction, follow the method of steps 2) to 4) and forge in the Z direction with the same compression rate. After the operation is completed, quickly immerse in water to cool.

[0025] The above is a single pass of the MDF process. Generally, to obtain finer grains, multiple passes of MDF are required to process the material. This allows the dislocations introduced during the forging process to be evenly stressed from all directions, fully refining the grains.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] This forming process is simple, efficient and low-cost. The use of this forming method can not only realize the application of the multi-directional forging process to thick plate materials with a thickness greater than 4mm, but also significantly improve the mechanical properties of the material and expand the application space of thick plate profiles. The left and right dies are embedded in the horizontal cylinder, and the fixed material thickness size gap serves as a constraint to prevent the sample from buckling due to compression deformation along the plate surface. The inclination angle of the horizontal cylinder cavity is small. When the vertical pressure head is subjected to the pressure of the press, it will generate pressure components perpendicular to the inner wall of the horizontal cylinder and the horizontal pressure cavity. The device can obtain a large horizontal load with a small vertical external force. The machining time is short and the production efficiency is high. This method can realize multi-directional forging deformation of large-size thick plate materials, so that the metal deformation is uniform, the flow is reasonable, the structure is dense, and the performance is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the workflow of the embodiment of the present application, a brief introduction to the drawings of the embodiment is given below.

[0029] Figure 1 Schematic diagram of a device using a horizontal pressure head with a pressure surface size of 40×80 mm in an embodiment of the present invention;

[0030] Figure 2A It is a left view of the present invention, Figure 2B This is a front view of the device of the present invention, Figure 2C is a top view of the device of the present invention;

[0031] Figure 3 It is a left side cross-sectional view of the present invention;

[0032] Figure 4 It is a schematic diagram of the force applied to the vertical pressure head in the process of the present invention;

[0033] Figure 5 Schematic diagram of a device using a vertical pressure head with a pressure surface size of 5×40 mm / 5×80 mm in an embodiment of the present invention;

[0034] Figure 6 It is a flow chart of multiple forging processes based on the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below in the form of specific embodiments in conjunction with the accompanying drawings.

[0036] like Figure 1 、 Figures 2A to 2C 、 Figure 3 and Figure 5 As shown, this embodiment provides a device for realizing multi-directional forging of large-size thick plate forgings, which includes: a left die 2, a right die 3, a horizontal cylinder 1, a horizontal pressing head 4, and a vertical pressing head 5.

[0037] The horizontal cylinder 1 is placed on the workbench, and the left mold 2 and the right mold 3 are embedded in the horizontal cylinder 1 along the inner inclined surface cavity. The left mold 2, the right mold 3, and the horizontal pressure head 4 are flush with the upper and lower surfaces of the horizontal cylinder 1.

[0038] One end of the left die 2 and the right die 3 is connected. The side surface formed by the connection serves as the extrusion cavity surface, and the other end forms a rectangular cavity as the extrusion cavity. The horizontal cylinder 1 is provided with a groove for guidance. The extrusion cavity ends of the left die 2 and the right die 3 are slid downward along the direction of the groove of the horizontal cylinder 1 to connect. During the forging process, the horizontal cylinder 1, the left die 2, and the right die 3 are all fixed and do not move.

[0039] After the billet is placed in the center of the extrusion cavity, the horizontal ram 4 is placed in the cavity retained between the left and right dies 2 and 3, fitting the billet. It provides the horizontal forming load, forming a complete extrusion cavity. The vertical ram 5 is embedded in the groove of the cavity within the horizontal cylinder 1. During the forging process, due to the relative height of the vertical ram 5 relative to the overflow, the vertical ram 5 moves obliquely downward along the inclined curved cavity of the horizontal cylinder 1, providing the horizontal forming load and driving the horizontal ram 4 to move toward the extrusion cavity to achieve the pressing of the slab. The horizontal ram 4 and the vertical ram 5 move in the opposite direction of the forging process to achieve horizontal die opening.

[0040] The components of the left mold 2 and the right mold 3 are Cr with high strength. 12 MoV steel, the horizontal pressure head 4 and the vertical pressure head 5 use 45 steel, and the good wear resistance makes the pressure head mold have a long service life.

[0041] like Figure 6As shown, this embodiment provides a process method for realizing multi-directional forging of forgings based on the device, and the specific steps are as follows:

[0042] 1) First, mark the surface of the blank with a size of 40×80 mm as X, and mark the other two orthogonal directions as Y and Z respectively, and then start forging. The forging process can be carried out at room temperature or under heating;

[0043] 2) First use the first set of molds (such as Figure 1 As shown in FIG1 , a forging operation is performed in the X direction. A vertical pressing head 5 is placed in the groove of the horizontal cylinder 1. Then, the left die 2 and the right die 3 are placed in the horizontal cylinder 1 along the edge of the vertical pressing head 5 so that the contact surfaces of the left die 2 and the right die 3 fit together.

[0044] 3) Remove the vertical pressing head 5 from the mold, place the lubricated billet into the extrusion cavity and fit it to the surface of the mold cavity, then insert the horizontal pressing head 4 to press the billet;

[0045] 4) Place the vertical pressure head 5 in the groove and perform a punching test. The punch of the press moves downward at a certain rate, and the displacement s of the vertical pressure head 5 is obtained according to the corresponding time, so as to calculate the horizontal compression displacement of the blank. The calculation formula is as follows:

[0046] Δl=s×tan5°

[0047] At this time, the calculation formula for the horizontal compressive stress of the blank is as follows:

[0048]

[0049] The calculation formula of the strain of the blank in the horizontal direction is as follows:

[0050]

[0051] According to the law of volume invariance, the strain calculation formula in the vertical direction is as follows:

[0052]

[0053] Where N is the load provided by the press, A is the area of ​​the pressing surface, l is the length of the blank in the vertical direction between the blank and the horizontal punch, and h is the height of the blank forged along the X direction;

[0054] 5) After the X-direction forging is completed, rotate the material 90°, the pressure surface is 5×40mm, and replace the second set of molds (such as Figure 5 As shown), select a pad of corresponding size as the horizontal pressing head and perform forging in the Y direction with the same compression rate;

[0055] 6) After forging in the Y direction, rotate the material and the pad together by 90°. The pressure surface is 5×80mm. Use the second set of dies to forge in the Z direction with the same compression rate. After the operation is completed, quickly immerse in water to cool.

[0056] The above is one-pass MDF process. To obtain finer grains, it is necessary to repeat multiple passes of MDF to process the material. This will allow the dislocations introduced during the forging process to be evenly stressed from all directions, thereby refining the grains.

[0057] The left and right dies are embedded in a horizontal cylinder, and their fixed material thickness dimensions and distance gaps serve as constraints to prevent buckling caused by compression deformation of the sample along the plate surface.

[0058] The horizontal cylinder cavity is inclined at an angle of 5° to the vertical direction, and the device can obtain a large horizontal load with a small vertical external force.

[0059] Applying the multi-directional forging process to thick plate materials will greatly improve the mechanical properties of the materials and expand the application space of thick plate profiles.

[0060] Effect verification:

[0061] The Mg-2Zn-0.2Ca alloy prepared by the multi-directional forging deformation preparation process in the present invention has a yield strength (YS) and an ultimate tensile strength (UTS) of 320 MPa and 360 MPa, respectively, which is compared with the strong plasticity (YS120 MPa and TS220 MPa) of the Mg-2Zn-0.2Ca alloy obtained by extrusion molding, and the mechanical properties of the material are significantly improved.

[0062] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. A thick plate multi-directional forging deformation preparation die device, characterized in that: The device comprises: a left mold (2), a right mold (3), a horizontal cylinder (1), a horizontal pressure head (4), and a vertical pressure head (5); The horizontal cylinder (1) has an inclined curved cavity; the left mold (2) and the right mold (3) are fixed in the inclined curved cavity of the horizontal cylinder (1) after being combined, and are consistent with the height of the horizontal cylinder (1); one end of the left mold (2) and the right mold (3) are respectively provided with a connecting end; after being combined, the side surface formed by the connecting end serves as the extrusion cavity surface, and the cavity surrounded by the other end and the horizontal cylinder (1) serves as the extrusion cavity; the outer curved surface of the left mold (2) and the right mold (3) has an angle θ with the vertical direction, and the angle is equal to the angle θ between the inner inclined curved surface of the cavity of the horizontal cylinder (1) and the vertical direction; The horizontal ram (4) is placed in the cavity between the left die (2) and the right die (3), with one side serving as the extrusion cavity surface and the other side of the horizontal cylinder (1) cavity wall forming a gap for installing the vertical ram (5). The contact surface between the vertical ram (5) and the horizontal cylinder (1) cavity wall is also provided with an angle θ with the vertical direction, so that when the vertical ram (5) moves downward under the pressure of the press, it will form a horizontal extrusion on the blank in the cavity through the horizontal ram (4) or directly; The angle θ between the inner inclined surface of the cavity of the horizontal cylinder (1), the vertical pressure head (5), the outer curved surfaces of the left mold (2) and the right mold (3) and the vertical direction ranges from 3° to 7°, and the vertical pressure head (5) is higher than the top surface of the horizontal cylinder (1).

2. The thick plate multi-directional forging deformation preparation die device according to claim 1, characterized in that: The horizontal cylinder (1) is provided with a groove for guidance, and one end of the extrusion cavity of the left mold (2) and the right mold (3) are connected by sliding downward along the direction of the groove of the horizontal cylinder (1).

3. The thick plate multi-directional forging deformation preparation die device according to claim 2, characterized in that: The vertical pressure head (5) is embedded in the groove of the inner cavity of the horizontal cylinder (1), forming a limit for the vertical pressure head (5).

4. The thick plate multi-directional forging deformation preparation die device according to claim 1, characterized in that: The composition of the left mold (2) and the right mold (3) is Cr 12 MoV steel, horizontal pressure head (4) and vertical pressure head (5) use 45 steel.

5. The thick plate multi-directional forging deformation preparation die device according to claim 1, characterized in that: The included angle θ between the inner inclined surface of the horizontal cylinder (1) cavity, the vertical pressure head (5), the left mold (2), and the outer curved surface of the right mold (3) and the vertical direction is 5°.

6. A thick plate multi-directional forging deformation preparation process based on the mold device according to claim 1, characterized in that: The specific steps of this method are: 1) First mark the material thickness direction as X, and the other two orthogonal directions as Y and Z, and then start forging. The forging process can be carried out at room temperature or under heating; 2) First, perform a forging in the X direction, place a vertical pressing head (5) in the groove of the horizontal cylinder (1), and then place the left die (2) and the right die (3) in the horizontal cylinder (1) along the edge of the vertical pressing head (5) so that the contact surfaces of the left die (2) and the right die (3) fit together; 3) Remove the vertical pressing head (5) from the mold, place the lubricated blank into the extrusion cavity to fit the surface of the mold cavity, and then place the horizontal pressing head (4) to press the blank; 4) A vertical pressure head (5) is placed in the groove to perform a punching test. The punch of the press moves downward at a rate v, and the displacement s of the vertical pressure head (5) is obtained according to the corresponding time t, thereby calculating the horizontal compression displacement of the blank. The calculation formula is as follows: Δl=s×tanθ=vt×tanθ At this time, the calculation formula of the horizontal compressive stress σ of the blank is as follows: The calculation formula of the strain of the blank in the horizontal direction is as follows: According to the law of volume invariance, the strain calculation formula in the vertical direction is as follows: Where N is the load provided by the press, A is the area of ​​the pressing surface, l is the length of the blank in the vertical direction between the blank and the horizontal punch, h is the height of the blank forged along the X direction, and θ is the inclination angle of the inner wall of the horizontal cylinder; 5) After the X-direction forging is completed, follow the method of steps 2) to 4) and forge the Y-direction at the same compression rate; 6) After forging in the Y direction, follow the method of steps 2) to 4) and forge in the Z direction with the same compression rate. After the operation is completed, quickly immerse in water to cool.

7. The thick plate multi-directional forging deformation preparation process according to claim 6, characterized in that: Steps 1) to 6) constitute one forging process, and steps 1) to 6) are repeated to complete multiple forging processes.

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