A method for designing a forging anvil for slab elongation

Abstract

The present application belongs to the field of metal processing, and particularly relates to a design method of a forging anvil for slab elongation, comprising the following steps: S1, determining the total width L of the anvil; S2, determining the parallel section length Lp and the circular arc section length Lr of the anvil; S3, determining the circular arc section of the anvil; S4, determining the total length B and the height H of the anvil; and S5, uniquely determining the working structure of the forging anvil according to S1-S4, and the working surface structures of the upper anvil and the lower anvil are the same. The present application designs a special forging anvil with a short parallel section and a long entrance and exit circular arc section, reduces the deformation dead zone during elongation, improves the deformation uniformity, and improves the axial pressure of the anvil on the blank through non-1 / 4 circular arc design, so as to promote the rapid elongation of the blank, i.e. to improve the elongation efficiency.

Description

Technical Field

[0001] This invention belongs to the field of metal processing, and specifically relates to a design method for a forging anvil used for drawing slabs. Background Technology

[0002] Free forging is a conventional metal plastic processing method. The upper and lower anvils of a press contact the metal, applying pressure to induce plastic deformation. Through multiple upsetting and drawing processes, the metal achieves the target dimensions and microstructure. Titanium alloys, due to their high specific strength, are the preferred material for lightweight, high-strength aerospace load-bearing components. With the continuous improvement of my country's equipment level, titanium alloy load-bearing components are gradually becoming more integrated and larger. The maximum weight of a single titanium alloy material used can reach 3 tons, and the titanium alloy billets selected for frame components are gradually shifting from bars to slabs. Large aerospace load-bearing titanium alloy slabs are often produced by free forging, with finished slab thicknesses ranging from 80mm to 200mm and a maximum projected area of ​​3m². 2 The free forging process for large-size titanium alloy slabs involves two deformation methods: upsetting and drawing. Drawing is the main method for slab forming in the later stages of processing. The forging anvil used in drawing forging has a significant impact on the slab surface quality, deformation uniformity, deformation efficiency, and microstructure uniformity.

[0003] Conventional forging anvils are flat anvils with slightly chamfered inlets and outlets, suitable for various deformations such as upsetting and drawing. These flat anvils have a large contact area with the metal during forging, resulting in significant deformation dead zones on the material surface due to contact friction. Furthermore, the increased width of the slab compared to bar drawing further amplifies this contact area. Since the core material lacks the constraint of anvil friction to participate in deformation normally, this difference in deformation between the surface and core further exacerbates the slab's microstructure inhomogeneity, often leading to microstructure delamination in the finished slab. In addition, the large contact dead zone during traditional flat anvil forging restricts metal flow and results in low drawing efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a design method for a forging anvil used in slab drawing. This invention designs a specialized forging anvil with a short parallel section and a long inlet / outlet arc section, reducing the deformation dead zone and improving deformation uniformity during drawing. Furthermore, the non-1 / 4 arc design increases the axial pressure of the anvil on the slab, promoting rapid length extension and thus improving drawing efficiency.

[0005] The technical solution provided by the present invention to achieve the above objectives is as follows:

[0006] A method for designing a forging anvil for drawing slabs includes the following steps:

[0007] S1, determine the total width L of the cutting board;

[0008] S2, determine the length of the parallel segment Lp and the length of the arc segment Lr of the anvil;

[0009] S3, determine the arc segment of the cutting board;

[0010] S4, determine the total length B and height H of the anvil;

[0011] S5, based on S1 to S4, the working structure of the forging anvil can be uniquely determined, and the working surfaces of the upper and lower anvils have the same structure.

[0012] Preferably, in step S2, the specific steps for determining the length Lp of the parallel segment and the length Lr of the arc segment of the anvil are as follows:

[0013] A1, determine the minimum value of the arc segment length Lr and the maximum value of the parallel segment length Lp;

[0014] A2, set the value of the parallel segment length Lp, and determine the value of the arc segment length Lr.

[0015] Preferably, in step A1, the specific method for determining the minimum value of the arc segment length Lr and the maximum value of the parallel segment length Lp is as follows: (Design:)

[0016] Lr≥Lp / 2

[0017] Where Lp is the length of the parallel segment and Lr is the length of the circular arc segment.

[0018] Preferably, in step S3, the specific steps for determining the arc segment of the anvil are as follows:

[0019] B1, the starting point P1 of the arc segment is determined by the length Lr of the arc segment and the length Lp of the parallel segment;

[0020] B2, determine the height H1 of the arc segment through the starting point P1;

[0021] B3, determine the endpoint P2 of the arc segment by the height H1 of the arc segment;

[0022] B4. The arc segment of the anvil is determined by the starting point P1 of the arc segment, the ending point P2 of the arc segment, and the tangency between the arc segment and the parallel segment of the working surface at point P1.

[0023] Preferably, in S4, the total length B of the cutting board is greater than the widest possible product width.

[0024] Preferably, in step S4, the height of the anvil is determined by the equipment operator based on the overall structural strength of the anvil. The height of the anvil is greater than the height of the material, and a value between 300mm and 600mm is recommended.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. On the one hand, wide arc segments are used to reduce the deformation dead zone and increase surface deformation, giving full play to the axial compression effect of the arc on the material surface, promoting the axial elongation of the material and improving the elongation efficiency.

[0027] 2. On the other hand, a non-1 / 4 arc design is adopted. This design supports the smooth design of the arc segment, that is, the arc is close to a straight line but not a straight line. During the drawing process, this design allows the slab to be fed into the drawing process with a very small amount of feed. The reduction of the drawing feed amount can effectively improve the deformation uniformity of the material. Attached Figure Description

[0028] Figure 1 This is a top view of the cutting board.

[0029] Figure 2 This is a front view of the cutting board.

[0030] Figure 3 A schematic diagram of the design method for circular arc segments.

[0031] In the diagram, L is the total width of the cutting board, Lp is the length of the parallel segment, Lr is the length of the arc segment, P1 is the starting point of the arc segment, P2 is the ending point of the arc segment, B is the total length of the cutting board, H is the height of the cutting board, H1 is the height of the arc segment, P3 is the center of the arc segment, and R is the radius of the arc. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and embodiments.

[0033] This invention discloses a method for designing a forging anvil for drawing slabs, comprising the following steps:

[0034] S1: Determine the total width L of the anvil: For large slabs with a thickness of 80-200mm, the width of the flat anvil ranges from 500-700mm. The anvil width L is defined as consisting of two circular arc segments (length Lr) on both sides and a parallel segment in the middle (length Lp). The circular arc segments are symmetrically distributed on both sides of the parallel segment, and the starting point of the arc is tangent to the ending point of the parallel segment. See Appendix. Figure 1 and attached Figure 2 .

[0035] The formula for the width L of the anvil is:

[0036] L=Lp+2Lr

[0037] Where Lp is the length of the parallel segment and Lr is the length of the circular arc segment.

[0038] S2: Determine the length of the parallel segment Lp and the length of the circular arc segment Lr.

[0039] A1. Determine the minimum value of the arc segment length Lr and the maximum value of the parallel segment length Lp.

[0040] The specific method is as follows: Design

[0041] Lr≥Lp / 2

[0042] Where Lp is the length of the parallel segment and Lr is the length of the circular arc segment.

[0043] Since L = Lp + 2Lr, the minimum value of Lr and the maximum value of Lp can be determined. The larger Lr is, the greater the tendency of the slab to bend during elongation.

[0044] Traditional flat anvils have a long parallel section. The chamfer on the anvil edge is only to avoid excessively sharp edges that could cause stress concentration and damage to the material. Therefore, the ratio of the chamfer radius to the parallel section length is very small, and the impact of the chamfer on the main deformation of the material during forging is negligible. Since the frictional force at the contact point between the material and the arc section is not parallel to the length of the material, the deformation at this point is less affected by friction. Therefore, by designing Lr ≥ Lp / 2, the role of the arc section in the deformation stage can be maximized. By reducing the parallel section length while increasing the arc length, the deformation of the material can be promoted, fundamentally changing the effect of the inlet and outlet arcs during the slab drawing process.

[0045] A2. Set the value of the parallel segment length Lp. The value of the arc segment length Lr can be determined according to L=Lp+2Lr.

[0046] Different materials have different hardness and softness, and their bending tendency also differs under the same degree of deformation. If the main products of the production line are products with high requirements for flatness, the lower limit of reliability Lr should be selected during the design.

[0047] S3: Arc Segment Design: The arc segments on both sides of the anvil are symmetrical, and the design method is the same. See Appendix. Figure 3 .

[0048] B1, the starting point P1 of the arc segment is determined by the length Lr of the arc segment and the length Lp of the parallel segment.

[0049] The intersection point P1 of segments Lp and Lr is the starting point of the arc segment of the anvil, and the arc segment is tangent to the working surface at point P1.

[0050] B2, determine the height H1 of the arc segment through the starting point P1.

[0051] The height of the arc segment is H1, the ratio of H1 to Lr is 0.3, and H1 is an integer value in millimeters between 50mm and 100mm.

[0052] B3, determine the endpoint P2 of the arc segment by using the height H1 of the arc segment.

[0053] The point on the side that is a distance from the working plane H1 is determined as the endpoint P2 of the arc. The arc segment is not tangent to the side of the anvil at P2.

[0054] B4. The arc segment of the anvil can be determined by the starting point P1 of the arc segment, the ending point P2 of the arc segment, and the relationship between the arc and the parallel segment of the working surface at point P1.

[0055] Draw the perpendicular bisector of line segment P1P2. Then, based on the tangency relationship between the arc segment and the parallel segment at point P1, obtain the foot of the perpendicular line at point P1. The intersection of the two lines is the center P3 of the uniquely determined arc segment. Line segment P1P3 is the radius R of the arc. Based on P3 and R, the uniquely determined arc connecting points P1 and P2 can be drawn.

[0056] The arc segment of the anvil is not a quarter circle. Using a non-quarter circle allows for an infinite increase in the arc radius while keeping the arc segment length fixed. This means the arc segment can approach a straight line infinitely. The gentler the arc segment, the stronger the biting ability of the material, allowing the slab to be fed in and stretched with a small feed rate.

[0057] S4: Determine the total length B and height H of the anvil: The total length of the anvil can be selected according to the size of the product to be forged, that is, the total length of the anvil should be greater than the widest possible product width; the height of the anvil is determined by the equipment operator based on the overall structural strength of the anvil, and the height of the anvil should be greater than the height of the material, and a value of 300mm to 600mm is recommended.

[0058] S5: The final working structure of the forging anvil can be uniquely determined based on S1 to S4, and the working surfaces of the upper and lower anvils have the same structure.

[0059] Finally, the anvil can improve the uniformity of the slab elongation structure.

[0060] The invention is further verified and illustrated through the following experimental examples:

[0061] The following is a specific example using a TC4 titanium alloy slab with a height of 200mm, a width of 1500mm, a length of 2500mm, and a length of 175mm, 1560mm, and 2950mm.

[0062] (1) Determine the total width L of the cutting board to be 700mm.

[0063] (2) According to the design of Lr≥Lp / 2, the minimum value of Lr is 175mm and the maximum value of Lp is 350mm. If Lp is set to 200mm, then Lr is determined to be 250mm based on the total width of 700mm.

[0064] (3) The position of point P1 can be determined by the values ​​of Lp and Lr; point P2 is determined by H / Lr = 0.3, which is rounded to get the height H1 from the working surface as 80mm. The position of point P2 is obtained from H1. The final arc segment is determined based on the relationship between point P1, point P2 and the tangency of the arc and the parallel segment at point P1.

[0065] (4) If the width of the slab after forging is 1560mm, then the total length B of the anvil should be greater than 1560mm, and is set to 2000mm. The height H of the anvil is 500mm, which is the common height of a regular flat anvil.

[0066] (5) The dimensions of the final working structure of the anvil can be uniquely determined by (1) to (4), and the anvil is made accordingly and forging tests are carried out.

Claims

1. A method for designing a forging anvil for drawing slabs, characterized in that, Includes the following steps: S1, determine the total width L of the cutting board; S2, determine the length of the parallel segment Lp and the length of the arc segment Lr of the anvil; In step S2, the specific steps for determining the length Lp of the parallel segment and the length Lr of the arc segment of the anvil are as follows: A1, determine the minimum value of the arc segment length Lr and the maximum value of the parallel segment length Lp; In step A1, the specific method for determining the minimum value of the arc segment length Lr and the maximum value of the parallel segment length Lp is as follows: Design: Lr≥Lp / 2 Where Lp is the length of the parallel segment and Lr is the length of the circular arc segment; A2, set the value of the parallel segment length Lp, and determine the value of the arc segment length Lr; S3, determine the arc segment of the cutting board; In step S3, the specific steps for determining the arc segment of the anvil are as follows: B1, the starting point P1 of the arc segment is determined by the length Lr of the arc segment and the length Lp of the parallel segment; B2, determine the height H1 of the arc segment through the starting point P1; In B2, the ratio of H1 to Lr is 0.3, and H1 takes an integer millimeter value between 50mm and 100mm. B3, determine the endpoint P2 of the arc segment by the height H1 of the arc segment; B4. The arc segment of the anvil is determined by the starting point P1 of the arc segment, the ending point P2 of the arc segment, and the tangency between the arc segment and the parallel segment of the working surface at point P1. S4, determine the total length B and height H of the anvil; S5, based on S1 to S4, the working structure of the forging anvil can be uniquely determined, and the working surfaces of the upper and lower anvils have the same structure.

2. The design method for forging anvils for slab drawing according to claim 1, characterized in that, In S4, the total length B of the cutting board is greater than the width of the widest product produced.

3. The design method for forging anvils for slab drawing according to claim 1, characterized in that, In step S4, the height of the anvil is determined by the equipment operator based on the overall structural strength of the anvil. The height of the anvil is greater than the height of the material, and the height of the anvil is between 300mm and 600mm.

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