Method and device for designing size of special-shaped lock catch structure of forging die for controlling displacement of forgings

Abstract

The application belongs to the field of forging and relates to a size design method and device of a special-shaped lock catch structure of a forging die for controlling displacement of a forged piece. The method comprises the following steps: acquiring the length H1 of a slope lead-in section of a lower die and the length H2 of an effective working section of the lower die; the effective working section is obtained by subtracting the slope lead-in section of an upper die from a straight wall working section; and the length and width of the special-shaped lock catch are set according to the shear force borne by the root of the special-shaped lock catch and the limit displacement force of the forged piece borne by the straight wall working section during the forming process of the forged piece.

Description

Technical Field

[0001] This invention belongs to the field of forging and relates to a method and device for designing the dimensions of a special-shaped locking structure for forging dies to control the misalignment of forgings. Background Technology

[0002] Current forging technology is trending towards near-net-shape forming. However, during the forging process, due to the combined effects of die processing, equipment errors, and the forging structure, misalignment in a certain direction often occurs between the upper and lower dies in various forgings. The selection of the design allowance for precision forgings is significantly influenced by this misalignment, especially for structural forgings with lateral forces. In these cases, regular misalignment exists between the upper and lower dies, and this misalignment often worsens with die use, easily leading to a decline in forging quality or even scrapping. For rotary forgings, there is uncertain offset; for structural forgings, there is offset and deflection. In such cases, guide pillars are used for guidance or equipment precision is relied upon. However, for structural forgings with lateral forces, the lifespan of guide pillars and dies is typically short. Closed-die forging (burr-free forging) is commonly used to produce precision forgings with small net allowances. However, this method, especially, places high demands on die processing. High surface finish and precision requirements on the die, coupled with uneven burr distribution, increase the risk of forging formation. Furthermore, vertical burrs exacerbate demolding difficulties, significantly impacting production continuity and die lifespan. Summary of the Invention:

[0003] The technical problem to be solved by this invention is to propose a design method and device for the dimensions of a special-shaped locking structure for forging die to control the misalignment of forgings. This method can effectively reduce the misalignment of forgings, solve the problem of damage that easily occurs during the installation and use of closed-die forging dies, alleviate the difficulty of demolding, improve the continuity of production and extend the die life by controlling the uniformity of flash.

[0004] Technical solution:

[0005] A method for designing the dimensions of a forging die with a non-standard locking structure that allows for controllable forging misalignment includes:

[0006] Obtain the length H1 of the inclined section of the lower die and the length H2 of the effective working section of the lower die; the effective working section is the straight wall working section minus the inclined section of the upper die.

[0007] The length and width of the irregular locking buckle are set based on the shear force borne at the root and the ultimate displacement force generated by the forging in the straight wall working section during the forging process.

[0008] The correspondence between the length and width of irregularly shaped latches:

[0009]

[0010] Where, l3 is the length of the latch, which is 1 / 4 to 1 / 6 of the mold length; B is the width of the latch, which is not less than 1 / 4 to 1 / 6 of the mold width; K is the safety factor, which is 1.3 to 2; F max σb represents the maximum lateral force during the forging process; σb represents the yield strength of the die material.

[0011] F max The methods for obtaining it include:

[0012] Numerical simulation of the forging process was performed to obtain the maximum lateral force exerted by the forging on the die.

[0013] F max The methods for obtaining it include:

[0014] A stress analysis was performed on the forging during the forging process to obtain the maximum lateral force exerted by the forging on the die.

[0015] Among them, F max =F.sinα.cosα

[0016] F is the maximum pressure required for the forging process, and α is the angle between the force direction and the horizontal direction.

[0017] The length and width of the irregularly shaped latch designed for lateral force are both greater than the length and width of the irregularly shaped latch designed for lateral force in the opposite direction.

[0018] A device for designing the dimensions of a forging die with a non-standard locking mechanism that can control forging misalignment includes:

[0019] The acquisition unit is used to acquire the length H1 of the inclined surface inlet section of the lower die and the length H2 of the effective working section of the lower die; the effective working section is the straight wall working section minus the inclined surface inlet section of the upper die.

[0020] The setting unit is used to set the length and width of the irregular locking buckle based on the shear force borne by the root of the irregular locking buckle and the ultimate displacement force generated by the forging in the straight wall working section during the forging process.

[0021] The correspondence between the length and width of irregularly shaped latches:

[0022]

[0023] Where, l3 is the length of the latch, which is 1 / 4 to 1 / 6 of the mold length; B is the width of the latch, which is not less than 1 / 4 to 1 / 6 of the mold width; K is the safety factor, which is 1.3 to 2; F max σb represents the maximum lateral force during the forging process; σb represents the yield strength of the die material.

[0024] Beneficial effects: This invention designs and obtains specific parameters for the irregular locking buckle by considering the mold's external dimensions, the structural features and external dimensions of the forging, and the ultimate misalignment force that may be generated during deformation. On the one hand, by controlling the gap between the upper and lower molds, relative misalignment and rotation between the upper and lower molds are prevented, effectively controlling the amount of misalignment generated by the forging and achieving the required amount of misalignment for the forging. On the other hand, the irregular locking buckle structure can counteract the misalignment force from the misalignment direction during the forging process, providing a method for calculating the structure and strength, and preventing mold damage or reduced lifespan due to insufficient strength of the irregular locking buckle structure. Attached Figure Description

[0025] Figure 1 A schematic diagram of a special-shaped locking structure for forging dies used to control misalignment of forgings.

[0026] Figure 2 This is a schematic diagram of the cross-section of an irregularly shaped locking mechanism.

[0027] Figure 3 This is a diagram for mechanical analysis. Detailed Implementation

[0028] Based on the structure and dimensions of the forging, the dimensions of the mold, and the maximum pressure required for forging, the lateral force is first calculated. This can be obtained using numerical simulation software. The maximum lateral force exerted by the forging on the mold can also be calculated by performing a stress analysis on the forging to determine the maximum lateral force that may be generated during the forming process.

[0029] right Figure 3 A force analysis is performed on a certain inclined forging. The forming pressure is F. After two force decompositions, the relationship between the maximum lateral force and the forming pressure is as follows:

[0030] F max =F.sinα.cosα;

[0031] F is the maximum pressure required for molding perpendicular to the horizontal plane, and α is the angle between the force direction and the horizontal direction. At this point, F... max This represents the maximum lateral force exerted by the forging on the die.

[0032] like Figure 1-3 As shown, the irregularly shaped lock needs to provide sufficient strength for the forging process, including the lock root being able to withstand the ultimate shear stress of the ultimate lateral force on the lock root, and the working surface also needing to meet the ultimate lateral stress during the forging process.

[0033] First, calculate the ultimate shear stress at the root of the irregular-shaped latch, i.e., the cross-section of the irregular-shaped latch. The cross-section of the working surface of the irregular-shaped latch should be able to withstand the maximum shear stress during deformation.

[0034] Then there is

[0035] σ b The yield strength of the mold material;

[0036] K is the safety factor, which is taken as 1.3-2;

[0037] l3 is the length of the latch on the side subjected to force.

[0038] but:

[0039] Secondly, the lateral force on the working surface of the irregularly shaped latch during deformation should also be calculated. It should then satisfy the following:

[0040]

[0041] but:

[0042] H2 is the straight-wall working section of the mold, and H1 is the inclined-face guide section of the mold;

[0043] According to mold design safety guidelines, even the weakest point should meet strength requirements. The L3 of the irregularly shaped locking mechanism should meet strength requirements in both the root cross-section and the working surface. Therefore:

[0044]

[0045] In addition to the above requirements, the relationship between the length L3 and width B of the irregular-shaped latch should also meet the following conditions:

[0046] Where l3 is the long side of the irregular buckle, which is usually 1 / 4 to 1 / 6 of the long side of the mold;

[0047] B is the short side of the lock, which is no less than 1 / 4 to 1 / 6 of the short side of the mold;

[0048] K is the safety factor, which is taken as 1.3-2;

[0049] Based on the lateral force requirements during the forging process, a larger safety factor can be selected on the side facing the lateral force to improve the mold life; on the side opposite to the lateral force, the irregular locking buckle mainly plays the role of ensuring the forming and does not bear the main lateral force, so its size can be selected with a smaller factor.

[0050] For example:

[0051] A typical forging cross section used in this invention is as follows: Figure 3 As shown, the forging has external dimensions of 1000×400×100mm, is made of TC4, has mold dimensions of 1800×1000×450mm, a forming tonnage of approximately 150MN, and an angle of 6° between the forming pressure slope and the horizontal plane.

[0052] Step 1: For the rectangular mold, select a four-corner straight-walled irregular-shaped locking buckle:

[0053] The second step is to calculate the maximum lateral stress:

[0054] F max =F.sinα.cosα

[0055] Its ultimate lateral force is approximately 15.6 MN.

[0056] The third step is to calculate L3 and B separately:

[0057]

[0058] σb is selected as 1300MPa;

[0059] but

[0060]

[0061] And satisfy

[0062]

[0063] When the forging thickness is 100mm, H1 is chosen to be 20mm, H2 is chosen to be 40mm, and the coefficient K is 2:

[0064] Calculations show that L3 should be greater than 325 mm, and L×B should be greater than 0.012 m2;

[0065] However, based on the fact that l3 is the long side of the irregular buckle, which is usually 1 / 4 to 1 / 6 of the long side of the mold, and B is the short side of the buckle, which is no less than 1 / 4 to 1 / 6 of the short side of the mold.

[0066] The molds can be selected as follows:

[0067] On the side facing the lateral force, irregular locking buckles are set at the two corners of the mold. The dimensions of the irregular locking buckles are: L3 is 330mm, B is 170mm, and L2 is 60mm, which can meet the requirements of the irregular locking buckles of the mold for the ultimate lateral force during the forging process.

Claims

1. A method for designing the dimensions of a forging die with a non-standard locking structure that allows for controllable forging misalignment, characterized in that, include: Obtain the length H1 of the inclined section of the lower die and the length H2 of the effective working section of the lower die; the effective working section is the straight wall working section minus the inclined section of the upper die. Based on the shear force borne by the root of the irregularly shaped lock during the forging process and the ultimate displacement force generated by the forging in the straight wall working section, the length and width of the irregularly shaped lock are set. The correspondence between the length and width of irregularly shaped latches: ； Where, l3 is the length of the latch, which is 1 / 4 to 1 / 6 of the mold length; B is the width of the latch, which is not less than 1 / 4 to 1 / 6 of the mold width; K is the safety factor, which is 1.3 to 2; F max This represents the maximum lateral force during the forging process. σ b The yield strength of the mold material.

2. The method according to claim 1, characterized in that, F max The methods for obtaining it include: Numerical simulation of the forging process was performed to obtain the maximum lateral force exerted by the forging on the die.

3. The method according to claim 1, characterized in that, F max The methods for obtaining it include: A stress analysis was performed on the forging during the forging process to obtain the maximum lateral force exerted by the forging on the die.

4. The method according to claim 2, characterized in that, The length and width of the irregularly shaped latch designed for lateral force are both greater than the length and width of the irregularly shaped latch designed for lateral force in the opposite direction.

5. A device for designing the dimensions of a forging die with a non-standard locking structure that can control the misalignment of forgings, characterized in that, include: The acquisition unit is used to acquire the length H1 of the inclined surface inlet section of the lower die and the length H2 of the effective working section of the lower die; the effective working section is the straight wall working section minus the inclined surface inlet section of the upper die. The setting unit is used to set the length and width of the irregular locking buckle based on the shear force borne by the root of the irregular locking buckle and the ultimate displacement force generated by the forging in the straight wall working section during the forging process. The correspondence between the length and width of irregularly shaped latches: ； Where, l3 is the length of the latch, which is 1 / 4 to 1 / 6 of the mold length; B is the width of the latch, which is not less than 1 / 4 to 1 / 6 of the mold width; K is the safety factor, which is 1.3 to 2; F max This represents the maximum lateral force during the forging process. σ b The yield strength of the mold material.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the method as described in any one of claims 1-4.

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