Shunt design method for combined extrusion of rotary body component

Abstract

The invention provides a split-flow design method for combined extrusion of a rotary body component, which comprises the following steps of: performing volume distribution pre-design according to the structure of the rotary body component, and performing metal split-flow pre-design in combination with an obtained volume distribution pre-design scheme to obtain a metal split-flow pre-design scheme; and then flow matching structure design is conducted by combining the obtained metal shunting pre-design scheme, and a composite extrusion forming scheme of the rotary body component is given. According to the method, the association model of the minimum shunting node in the combined extrusion process and the characterization function of the position of the minimum shunting node and the critical time are established, so that the metal flow rule of the minimum shunting node is mastered, and accurate regulation and control of upper and lower shunting of combined extrusion of the rotary body component are realized; the problems that local metal is transferred too much, and vortex or turbulent flow occurs during metal flowing are effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of composite extrusion forming of rotating body components, and in particular to a flow splitting design method for composite extrusion of rotating body components. Background Art

[0002] The key process of composite extrusion of rotating body components is mainly the pre-design of metal diversion, which directly affects the flow law and forming quality of the metal. When the pre-design of metal diversion is unreasonable, the flow speed of the upper outlet metal and the lower outlet metal is likely to be mismatched, resulting in defects such as partial metal filling or excessive local metal transfer, eddy current or turbulence in the metal flow, etc., which requires improved design of the process or multiple forming processes, which seriously affects the efficiency and manufacturing cycle of the rotating body components.

[0003] For a certain rotating body component, due to unreasonable pre-design of metal diversion (such as Figure 2 As shown in Figure 2), the hollow ring structure at the lower end has a small metal flow resistance and a large volume transfer (as shown in Figure 2). Figure 3 As shown), the metal in the hollow ring structure at the upper end generates eddy currents and flows back downwards (as shown Figure 4 As shown in the figure, it is impossible to achieve the design purpose of one-time composite extrusion forming, and it is even more difficult to accurately control the metal diversion method, and the material utilization rate is low, which affects the product manufacturing performance.

[0004] At present, the diversion design of composite extrusion of rotating body components mainly adopts design experience to conduct repeated trial and error of process solutions. There are a series of problems such as long product development cycle, redundant design blanks are not refined, and there is a lack of clear forming theoretical basis and laws. Summary of the invention

[0005] At least in view of the problems mentioned in the background technology, the present invention aims to provide a flow diversion design method for composite extrusion of rotating body components.

[0006] The present invention adopts the following technical solution.

[0007] A flow splitting design method for composite extrusion of a rotating body component, comprising the following steps: Step 1, pre-designing the volume distribution according to the structure of the rotating body component; wherein the forging of the rotating body component (i.e., the extruded blank for machining the rotating body component) has an upper outlet circular ring portion and a lower hollow protruding structure, and the lower hollow protruding structure is a composite structure of a conical transition and a circular protrusion; Step 2, performing metal flow splitting pre-design in combination with the obtained volume distribution pre-design scheme to obtain a metal flow splitting pre-design scheme; Step 3: Based on the obtained pre-designed metal flow splitting scheme, conduct the flow matching structure design and present the compound extrusion forming scheme for the rotary body component; this Step 3 is the key design stage for metal flow splitting in the flow matching structure design, where the flow velocities of the metal at the upper ring outlet part and the metal at the lower outlet tapered transition part are different in this stage.

[0008] As an optimized scheme, the compound extrusion forming is designed in two stages: In the first stage, the billet metal simultaneously flows to the upper outlet ring part and the lower outlet tapered transition part until the filling of the lower outlet tapered transition part is completed; in the second stage, the billet metal continues to simultaneously flow to the upper outlet ring part and the lower outlet ring part until the designed height of the ring part is reached.

[0009] As an optimized scheme, the steps of the pre-design of volume distribution include: Control the volume ratio η of the metal in the lower outlet ring part and the metal in the upper outlet ring part in the second stage according to Equation (1), In the formula, d 1down is the outer diameter of the lower outlet ring part, d 2down is the inner diameter of the lower outlet ring part, d 1up is the outer diameter of the upper outlet ring part, d 2up is the inner diameter of the upper outlet ring part, and the metal in the lower outlet ring part refers to the metal in the cavity corresponding to the lower outlet ring part; Determine the height of the billet consumed for metal transfer when the deformation in the second stage is completed according to the equal volume principle and Equation (2), In the formula, L0 is the filling height of the lower outlet ring part in this stage, and L1 is the filling height of the upper outlet ring part in this stage.

[0010] As an optimized scheme, the steps of the pre-design of metal flow splitting include: In the compound extrusion deformation process of the first stage, the minimum flow splitting node is set near the edge of the billet; Assume that there are N minimum flow splitting node time-position coordinates P i (t i , y i ) distributed along the time-alternating order and the height direction at the edge of the billet. t i is the critical time of the i-th minimum flow splitting node, and y i is the initial height of the i-th minimum flow splitting node from the surface of the billet. Then, the flow velocity of the i-th minimum flow splitting node at the critical time t i is close to 0; at this time, the instantaneous deformation height h i = h0 - v0t i , where h0 is the original height of the billet and v0 is the downward speed of the punch; Design the minimum shunt node time-position coordinate P at the start of the first-stage combined extrusion deformation start (t0, y s ) and the minimum shunt node time-position coordinate P at the completion of the deformation of the conical transition part end (t e , y e ), where t0 is the critical time at the start of the deformation, t e is the critical time at the completion of the deformation of the conical transition part, and y s is the initial height of the minimum shunt node from the billet surface at the start of the deformation, and y e is the initial height of the minimum shunt node from the billet surface at the completion of the deformation of the conical transition part, which satisfies Here, g0 is the designed thickness of the intermediate web of the forging (i.e., the bottom thickness of the middle part of the forging); at this time, the instantaneous deformation height of the corresponding billet is h e = g0 + g1, and the time is calculated as Furthermore, the initial height y of the i-th minimum shunt node from the billet surface is established i and the characterization relationship with the critical time t i is y i = f(t i ).

[0011] As a preferred solution, the steps for the design of the flow matching structure include: During the first-stage combined extrusion deformation, the instantaneous height of the i-th minimum shunt node from the upper surface of the billet is h iup = y i -(h0 - h i ), and the instantaneous height of the i-th minimum shunt node from the lower surface of the billet is h idown = h0 - y i . Calculate the transfer time Δt between two adjacent minimum shunt nodes i = t i - t i-1 , then the average instantaneous flow velocity of the metal from the minimum shunt node of the combined extrusion to the upper outlet ring part The average instantaneous flow velocity of the metal from the minimum shunt node of the combined extrusion to the lower outlet conical transition part is The volume V of the billet transferred by the punch drive during this time period (the discretely designed differential time period, i.e., the time period from t i to t i+1 ) is equal to the sum of the volume V i of the billet metal flowing simultaneously to the upper outlet ring part and the volume V iup flowing to the lower outlet conical transition part, that is, V idown = V i = Viup +V idown , where here, s0 is the initial area of the blank, s iup is the instantaneous area of the metal from the minimum shunt node of the compound extrusion to the upper outlet, s idown is the instantaneous area of the metal in the conical transition part from the minimum shunt node of the compound extrusion to the lower outlet; d t represents the time interval for the calculus calculation, belonging to the time difference from t i to t i+1 ; According to the principle of equal volume, design the geometric structure of the conical transition part at the lower outlet, which can be iteratively optimized through 3D modeling software to design the geometric shape of the conical transition part; finally, obtain the forging drawing to ensure reasonable metal shunting during the forming process and achieve the overall forming at one time to reach the designed structure of the forging.

[0012] Advantageous effects: By establishing the correlation model of the minimum shunt node in the compound extrusion process and the characterization function of the position of the minimum shunt node and the critical time, the present invention has mastered the metal flow law of the minimum shunt node, realized the precise control of the upper and lower shunts of the compound extrusion of the rotary body component, and effectively solved the problems such as excessive local metal transfer, eddy current or turbulent flow of metal flow; adopting the solution of the present invention can accurately guide the analysis of the compound extrusion deformation law of the rotary body component and the optimization design of its forging structure, can provide a clear theoretical basis for the forming of the rotary body component, can accurately master the shunting method of the compound extrusion of the rotary body component, is beneficial to improving the forming quality and efficiency of the rotary body component, is beneficial to improving the material utilization rate, and has wide application value in materials such as aluminum alloy, magnesium alloy, titanium alloy, and alloy steel. Brief description of the drawings

[0013] Figure 1 is a schematic diagram of the rotary body component and its forging in Embodiment 1; Figure 2 is a schematic diagram of the unreasonable pre-design of the metal shunting of the rotary body component in the prior art; Figure 3 is a schematic diagram of the small metal flow resistance and large volume transfer at the lower end hollow annular structure of the rotary body component in the prior art; Figure 4 is a schematic diagram of the eddy current and downward backflow of the metal at the upper end hollow annular structure of the rotary body component in the prior art; Figure 5 is a schematic diagram of the geometric relationship between the mold and the blank in Embodiment 1; Figure 6 is a schematic diagram of the correlation model of the minimum shunt node in the compound extrusion in Embodiment 1; Figure 7It is the deformation analysis diagram of the minimum shunt node at the start of deformation in Example 1. In the figure, part a corresponds to a blank height of 28 mm and a circular lower die outlet; part b corresponds to a blank height of 28 mm and a conical lower die outlet. Figure 8 It is the simulation analysis diagram of the rotary body component in Example 1; Figure 9 It is the diagram of the initial position of the inserted node during the simulation process; Figure 10 It is the data diagram of the axial velocity and time of the inserted node during the simulation process; Figure 11 It is the relationship diagram between the starting position and the minimum velocity of the inserted node during the simulation process; Figure 12 It is the relationship diagram between the initial position and the critical time of the shunt node (comparison between Example 1 and simulation); Figure 13 It is the relationship diagram between the instantaneous blank height and the initial position of the shunt node (comparison between Example 1 and simulation); Reference numerals: 1 - Forged part of the rotary body component, 2 - Rotary body component, 3 - Punch, 4 - Die, 5 - Blank, 6 - Upper outlet ring part, 7 - Conical transition (structure), 8 - Ring protrusion (structure), 9 - Center of the instantaneous blank height, 10 - Blank height required for metal transfer to complete during the second-stage deformation (this g1 height region). Detailed implementation manners

[0014] Next, in conjunction with the accompanying drawings, the technical solutions in the present invention will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Example 1

[0015] The structures of a certain rotary body component 2 and its forged part 1 are as Figure 1 shown. After the forged part 1 is formed by extrusion, it is machined into the rotary body component 2. The forged part 1 has an upper outlet ring part 6 and a lower hollow protruding structure at the lower end. The lower hollow protruding structure is a composite structure of a conical transition 7 and a ring protrusion 8. In order to realize the one-step forming of the forged part 1 of the rotary body component 2, the composite extrusion forming is designed in two stages. In the first stage, the metal of the blank simultaneously flows to the upper outlet ring part and the lower outlet conical transition part until the filling of the lower outlet conical transition part is completed. In the second stage, the blank metal continues to flow to the upper outlet ring part and the lower outlet ring part simultaneously until the designed height of the ring part is reached.

[0016] In this example, the split-flow design method for the compound extrusion of a rotary body component (essentially extruding the forging 1 corresponding to the rotary body component 2): Step 1, perform a preliminary volume distribution design according to the structure of the rotary body component; among them, the forging 1 of the rotary body component 2 has an upper outlet ring part 6 and a lower hollow protruding structure 7. The upper outlet ring part 6 is a ring, and the lower hollow protruding structure is a composite structure of a tapered transition 7 and a ring protrusion 8; Step 2, perform a preliminary metal split-flow design in combination with the obtained preliminary volume distribution design plan; Step 3, perform a flow matching structure design in combination with the obtained preliminary metal split-flow design plan, and give a compound extrusion forming plan for the rotary body component. Among them, Step 2 can be understood as the preliminary metal split-flow design stage of the flow matching structure design (volume pre-distribution, in this stage, the metal flow velocities at the upper and lower ring outlet parts are basically the same), and Step 3 can be understood as the key metal split-flow design stage of the flow matching structure design (volume regulation, in this stage, the metal flow velocities at the upper ring outlet part and the lower outlet tapered transition part are different). Specifically as follows.

[0017] In this example, the steps of the preliminary volume distribution design: Combine Figure 5 As shown, design the outer diameter d of the lower outlet ring part of the forging 1 1down to be 116 mm, the inner diameter d of the lower outlet ring part 2down to be 94 mm, the outer diameter d of the upper outlet ring part 1up to be 125 mm, and the inner diameter d of the upper outlet ring part 2up to be 103 mm. Calculate the volume ratio of the metal in the lower outlet ring part and the metal in the upper outlet ring part of the compound extrusion at the end of the second-stage deformation to be 0.92. At the same time, design the filling height L0 of the lower outlet ring part in this stage to be 11 mm and the filling height L1 of the upper outlet ring part to be 6 mm. Calculate the billet height required for metal transfer at the end of the second-stage deformation according to the equal-volume principle to be 7.63 mm.

[0018] In this example, the steps of the preliminary metal split-flow design: Combine Figure 6 As shown, during the first-stage compound extrusion deformation process, the minimum split-flow node is at the edge of the billet ( Figure 6 the outermost vertical line in it, and there are many horizontal lines on this line, and these horizontal lines represent the transient split-flow points), and it gradually approaches the instantaneous billet height center 9 as the deformation progresses. The instantaneous billet height center 9 is transiently changing, and finally it is near Pg, that is, g2 = 0.5g0. The billet height required for metal transfer at the end of the second-stage deformation is represented by the reference numeral 10 in the figure, and the g1 height region in the figure; Assume that there are N minimum split-flow node time-position coordinates P at the edge of the billet according to the time-alternating order and distribution along the height direction i (ti , y i ), t i is the critical time of the i-th minimum shunt node, y i is the initial height of the i-th minimum shunt node from the billet surface. Then, the flow velocity of the i-th minimum shunt node at the critical time t i is close to 0. At this time, the instantaneous deformation height h of the billet i = h0 - v0t i , where h0 is the original height of the billet and is designed to be 28 mm, and v0 is the downward speed of the punch and is designed to be 10 mm / s; Design the time-position coordinate P of the minimum shunt node at the start of the first-stage compound extrusion deformation start (t0, y s ) and the time-position coordinate P of the minimum shunt node when the deformation of the conical transition part is completed end (t e , y e ), where t0 is the critical time at the start of deformation and is taken as 0, and t e is the critical time when the deformation of the conical transition part is completed, and y s is the initial height of the minimum shunt node from the billet surface at the start of deformation. After analysis and design, y s is 6 mm (as shown in Figure 7 ), and y e is the initial height of the minimum shunt node from the billet surface when the deformation of the conical transition part is completed, and it satisfies Here, g0 is the thickness of the intermediate web of the forging and is designed to be 11.5 mm (the height of g0 in Figure 6 , that is, the bottom thickness of the intermediate part of the forging). Then, by calculation, y e is 14.62 mm. At this time, the corresponding instantaneous deformation height h of the billet e = g0 + g1 is 19.13 mm, and the calculated time is 0.887 s; Furthermore, use linear fitting to obtain the characterization relationship y start (t0, y s ) and P end (t e , y e ) as y i = 6 + 9.72t i . Let the value of N nodes be 30. Then, calculate the initial height y of each minimum shunt node from the billet surface i and the instantaneous deformation height h of the billet i , as shown in Table 1; Table 1 Related values of the minimum shunt node during the first-stage compound extrusion deformation

[0019] Steps for designing the flow matching structure in this example: During the first-stage compound extrusion deformation process, the instantaneous height h of the i-th minimum flow-dividing node from the upper surface of the blank iup = y i -(h0 - h i ), and the instantaneous height h of the i-th minimum flow-dividing node from the lower surface of the blank idown = h0 - y i , calculate the transfer time Δt between two adjacent minimum flow-dividing nodes i = t i - t i-1 , then the average instantaneous flow velocity of the metal from the minimum flow-dividing node of the compound extrusion to the upper outlet circular ring part The average instantaneous flow velocity of the metal from the minimum flow-dividing node of the compound extrusion to the lower outlet conical transition part The volume V of the blank transferred by the punch during this period i is equal to the sum of the volume V iup flowing upward to the upper outlet circular ring part and the volume V idown flowing to the lower outlet conical transition part of the blank metal, that is, V i = V iup + V idown , where here s0 is the initial area of the blank, s iup is the instantaneous area of the metal from the minimum flow-dividing node of the compound extrusion to the upper outlet, and s idown is the instantaneous area of the metal from the minimum flow-dividing node of the compound extrusion to the lower outlet conical transition part; According to the principle of equal volume, design the geometric structure of the lower outlet conical transition part of the compound extrusion (the geometric shape of the conical transition part can be iteratively optimized through 3D modeling software; finally, a forging drawing can be obtained, which can ensure reasonable metal flow diversion during the forming process and achieve a one-piece overall forming to reach the designed structure of the forging).

[0020] Use the simulation test method to verify and optimize the forging shape of the designed rotary body component and the compound extrusion flow diversion design method. The simulation process shows good metal filling (as Figure 7 and Figure 8 shown), without vortex and turbulent flow phenomena, and reasonable metal volume distribution at the upper and lower outlet parts of the forging. Interpolate 21 nodes at the edge of the blank (as Figure 9 shown) to track and analyze the simulation process (as Figure 10 shown), and it can be found that the minimum velocity of the 6th - 12th interpolation nodes tends to 0 (as Figure 11As shown, it is the minimum shunt node. By comparing the deformation law of the minimum shunt node calculated and simulated in this embodiment, it can be found that the relationship between the initial position of the shunt node and the critical time, and the relationship between the instantaneous height of the blank and the initial position of the shunt node have high accuracy (as Figure 12 and Figure 13 shown), indicating that the shunt design method is feasible.

Claims

1. A split-flow design method for compound extrusion of a rotary body component, characterized in that the steps Including: Step 1: Conduct a preliminary design of volume distribution according to the structure of the rotary body component; wherein, the forging of the rotary body component has an upper outlet ring part and a lower end hollow protruding structure, and the lower end hollow protruding structure is a composite structure of tapered transition and ring protrusion; Step 2: Combine the obtained preliminary volume distribution design scheme to conduct a preliminary design of metal flow splitting to obtain a preliminary metal flow splitting design scheme; Step 3: Combine the obtained preliminary metal flow splitting design scheme to conduct a flow matching structure design and give a composite extrusion forming scheme for the rotary body component.

2. The method according to claim 1, wherein The composite extrusion forming design is divided into two stages: In the first stage, the blank metal flows simultaneously to the upper outlet ring part and the lower outlet tapered transition part until the filling of the lower outlet tapered transition part is completed; In the second stage, the blank metal continues to flow simultaneously to the upper outlet ring part and the lower outlet ring part until the designed height of the ring part is reached.

3. The method according to claim 2, characterized in that, The steps of the preliminary volume distribution design include: Control the volume ratio η of the metal in the lower outlet ring part and the metal in the upper outlet ring part in the second stage according to Equation (1), and the value of η is taken as 0.9 - 1.1, where d 1down is the outer diameter of the lower outlet ring part, d 2down is the inner diameter of the lower outlet ring part, d 1up is the outer diameter of the upper outlet ring part, d 2up is the inner diameter of the upper outlet ring part; Determine the height of the blank consumed by metal transfer when the deformation in the second stage is completed according to the principle of equal volume and Equation (2) In the formula, L0 is the filling height of the lower outlet ring part in this stage, and L1 is the filling height of the upper outlet ring part in this stage.

4. The method according to claim 3, wherein The steps of the preliminary metal flow splitting design include: In the composite extrusion deformation process of the first stage, the minimum flow splitting node is set near the edge of the blank; Assume that there are N minimum shunt node time - position coordinates P distributed in the order of time alternation and along the height direction at the blank edge i (t i , y i ), where t i is the critical time of the i - th minimum shunt node, and y i is the initial height of the i - th minimum shunt node from the blank surface. Then the flow velocity of the i - th minimum shunt node at the critical time t i is close to 0; at this time, the instantaneous deformation height h i = h0 - v0t i , where h0 is the original height of the blank and v0 is the downward speed of the punch; Design the time - position coordinate P of the minimum shunt node at the start of the first - stage compound extrusion deformation start (t0, y s ) and the time - position coordinate P of the minimum shunt node when the deformation of the conical transition part is completed end (t e , y e ), where t0 is the critical time at the start of the deformation, t e is the critical time when the deformation of the conical transition part is completed, y s is the initial height of the minimum shunt node from the billet surface at the start of the deformation, y e is the initial height of the minimum shunt node from the billet surface when the deformation of the conical transition part is completed, and it satisfies Here, g0 is the designed thickness of the intermediate web of the forging; at this time, the instantaneous deformation height of the corresponding billet is h e = g0 + g1, and the calculated time Further establish the initial height y of the i-th smallest shunting node from the billet surface i and the critical time t i The characterization relationship is y i = f(t i ).

5. The method according to claim 4, wherein The steps of the flow matching structure design include: During the first-stage compound extrusion deformation process, the instantaneous height of the $i$-th minimum flow-division node from the upper surface of the blank is $h$ iup $= y$ i $-(h_0 - h$ i ), and the instantaneous height of the $i$-th minimum flow-division node from the lower surface of the blank is $h$ idown $= h_0 - y$ i . Calculate the transfer time $\Delta t$ between two adjacent minimum flow-division nodes i $= t$ i $- t$ i-1 . Then, the average instantaneous flow velocity of the metal in the part from the minimum flow-division node of the compound extrusion to the upper outlet circular ring The average instantaneous flow velocity of the metal in the part from the minimum flow-division node of the compound extrusion to the lower outlet conical transition The volume V of the punch driving the blank transfer during this period i is equal to the sum of the volume V flowing upward to the upper outlet ring part and the volume V of the lower outlet conical transition part simultaneously with the blank metal, that is, V iup idown = V i iup + V idown , where here s0 is the initial area of the blank, s iup is the instantaneous area of the metal from the minimum diversion node of the compound extrusion to the upper outlet, and s idown is the instantaneous area of the metal from the minimum diversion node of the compound extrusion to the lower outlet conical transition part. dt belongs to the time difference from t i to t i+1 ;​​ Design the geometric structure of the lower outlet tapered transition part according to the principle of equal volume to design the geometric shape of the tapered transition part; Finally, obtain the forging drawing.

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