Omega-shaped piece multi-directional die forging and pressure reduction composite forming method

Abstract

The application discloses a multi-directional die forging and pressure reduction composite forming method of an omega-shaped piece, and belongs to the field of forging. The application solves the problems of high forming load and large die eccentric load of the multi-directional die forging of the omega-shaped piece. The application is used for the multi-directional die forging and pressure reduction composite forming of the omega-shaped piece.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of forging. BACKGROUND

[0002] Lightweight structure design and overall manufacturing are important technical approaches to meet the high speed and high strength requirements of modern aerospace vehicles. As a key oil storage bearing component of a spacecraft, the Ω-shaped piece is composed of a U-shaped curved web, flanges on both sides of the web, and reinforcing ribs distributed along the web. The structure is complex. For such a component, the use of square bar machining manufacturing will result in a huge waste of material and a serious waste of machining time. The ordinary one-way loading die forging forming method is extremely difficult to form the flanges and curved reinforcing ribs with large thickness, and the forging is difficult to demold. Since the Ω-shaped piece has obvious characteristics in two perpendicular directions, the use of multi-directional die forging is more beneficial to its forming.

[0003] Currently, multi-directional die forging process is usually used for the forming of multi-pass pipe components, which has prominent structural characteristics and mature process design ideas, but there are few reports on the multi-directional die forging process of rib plate components. The multi-directional die forging form of multi-pass pipe components is mainly open extrusion without flash, and the forming relative load is small. The shape characteristics of the Ω-shaped piece determine that it is more suitable for forming by open die forging with flash, and the load is relatively large. Since the maximum load of the side pressure cylinder is usually less than that of the upper pressure cylinder, the lack of side load is particularly obvious, therefore, the traditional two-step simple loading path of up-down and left-right cannot meet the forming load demand. In addition, the Ω-shaped piece has low symmetry in the opening direction, and this asymmetry will generate a large bias load perpendicular to the loading direction on the die during multi-directional die forging, causing die damage. In order to reduce the bias load, the multi-directional die forging die structure for the Ω-shaped piece must be reasonably designed. SUMMARY

[0004] The present application solves the problems of high forming load and large die bias load in the existing multi-directional die forging of the Ω-shaped piece, and further provides a multi-directional die forging and split-flow pressure reduction composite forming method for the Ω-shaped piece.

[0005] A multi-directional die forging and split-flow pressure reduction composite forming method for the Ω-shaped piece, which is carried out according to the following steps:

[0006] I. Die design:

[0007] Design a multi-directional die forging and split-flow pressure reduction composite forming die for the Ω-shaped piece;

[0008] The Ω-shaped piece is composed of a U-shaped curved web, flanges on both sides of the web, and Ω-shaped reinforcing ribs. The flanges are arranged on both sides of the opening of the U-shaped curved web, and a plurality of Ω-shaped reinforcing ribs are uniformly arranged along the outer surfaces of the U-shaped curved web and the flanges;

[0009] The multi-directional die forging and pressure reduction composite forming die is composed of an upper pad, a lower pad, a pair of side pads, an upper die, a lower die, a pair of side dies, a lower ejector block, a pair of side blocks and a lower die pressing plate; the lower ejector block is arranged in the middle of the lower die, the punch of the upper die, the lower die, the pair of side dies and the lower ejector block form an Ω-shaped part cavity, and a flange cavity is arranged on the pair of side dies, and an Ω-shaped reinforcing rib cavity is arranged on the lower die, the pair of side dies and the lower ejector block;

[0010] The upper die and the pair of side dies are split on the upper surface of the flange of the Ω-shaped part, and the split surface is parallel to the movement direction of the upper die; the vertical distance from the split surface to the deepest part of the flange cavity of the side die is B 6f , the vertical distance from the surface of the U-shaped curved web cavity of the side die to the deepest part of the flange cavity is B 6w , and B 6f :B 6w =(0.5-0.9):1;

[0011] The pair of side dies are provided with guide blocks at both ends in the length direction of the Ω-shaped part, and the lower die is provided with guide grooves at the positions corresponding to the guide blocks; the lower die is provided with a pressing plate groove at the middle position of the upper surface of the side wall at both ends of the cavity in the length direction of the Ω-shaped part, and the pressing plate groove is used for placing the lower die pressing plate;

[0012] II. Forming:

[0013] ① The aluminum alloy blank and the multi-directional die forging and pressure reduction composite forming die are lubricated and heated;

[0014] ② The pair of side dies are opened, the heated aluminum alloy blank is placed in the cavity formed by the lower die and the lower ejector block, and the upper die is pressed down to the position at a speed v1;

[0015] ③ The pair of side dies are fed at a speed v2 until the side pressure cylinder load of the press is (0.7-0.9)F6, wherein F6 is the maximum load limit of the side pressure cylinder of the press;

[0016] ④ The pair of side dies are retracted to the side without load, the lower die pressing plate is placed in the pressing plate groove, the upper die is pressed down until the lower surfaces of the punch of the upper die at both ends in the length direction of the Ω-shaped part contact the lower die pressing plate, at this time, the vertical distance between the lower end of the punch of the upper die and the upper surface of the bottom of the formed part is h, and the upper pressure cylinder load of the press is ≤0.5F t and ≥0.3F6, wherein F t is the maximum load limit of the upper pressure cylinder of the press;

[0017] ⑤ The pair of side dies continue to be fed at the speed v2 until the side pressure cylinder load of the press is (0.7-0.9)F6;

[0018] (5) a pair of side dies retreats to the distance b between the U-shaped curved side wall surface of the formed part and the U-shaped curved web cavity side wall surface of the side die, the upper die is lifted up, the lower die pressing plate is removed, and then the upper die continues to be pressed down to the upper cylinder load of the press reaches (0.7-0.9) F6 t or the side cylinder load reaches (0.7-0.9) F6, and b=(0.05-0.15) T, wherein T is the wall thickness of the U-shaped side wall of the formed part after step (5) is completed.

[0019] (6) the upper die and the pair of side dies are retracted, the lower ejector block ejects the formed part, and the multi-directional die forging and split-flow pressure reduction combined forming method of the Ω-shaped part is completed.

[0020] The present application has the following beneficial effects:

[0021] The present application is aimed at the problems of high forming load and large die bias force in the multi-directional die forging of the Ω-shaped part, and a multi-directional die forging and split-flow pressure reduction combined forming method is designed. When the forming load of the side die approaches the maximum value, the upper die is lifted up to a certain height, so that a gap is generated between the upper die and the formed part, and then the side continues to be loaded, part of the deformed metal fills the flange and the rib, and the other part flows to the gap between the upper die and the formed part, achieving the effect of split-flow pressure reduction and reducing the forming pressure of the side.

[0022] In the present application, the side pads below the side dies are fixed on the lower pad plate, which can support the side dies and effectively offset the downward bias load of the side dies. In view of the problem of large upward bias force of the multi-directional die forging die of the Ω-shaped part, a parting method of the upper die and the side die is designed to reduce the area difference of the upper and lower surfaces of the flange cavity of the side die in the vertical direction and reduce the bias force. At the same time, guide blocks and guide grooves are arranged on the side die and the lower die respectively. During side forming, the guide blocks are inserted into the guide grooves, and the upward bias force is borne by the guide blocks and the guide grooves, avoiding the damage of the side die root and the bolts directly bearing excessive bending moment. Before the upper die is lifted up and the side die continues to feed, a lower die pressing plate is added between the upper and lower dies, and the upper die exerts a certain pressure on the lower die pressing plate, avoiding the bias of the two side dies with different tonnages acting on the upper die without load, which leads to the upper die and the upper die bolts bearing excessive bending moment and being damaged. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 For the Ω-shaped part model described in step one of the embodiment, (a) is a perspective view, and (b) is a front view.

[0024] Figure 2 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0025] Figure 3 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks; Figure 2 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0026] Figure 4 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks; Figure 4 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0027] Figure 5 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks; Figure 5 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0028] Figure 6 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0029] Figure 7 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks; Figure 6 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0030] Figure 8 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0031] Figure 9 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0032] Figure 10 The front structure sectional view of the multi-directional die forging and flow dividing pressure reducing combined forming die described in step one of the embodiment, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side blocks;

[0033] Figure 11For the embodiment step one described in the multi-directional die forging and split-flow pressure reduction composite forming die physical map, 1 is the upper pad, 2 is the lower pad, 3 is a pair of side pads, 4 is the upper die, 5 is the lower die, 6 is a pair of side dies, 7 is the lower top block, 8 is a pair of side pads;

[0034] Figure 12 For the embodiment one preparation of the Ω-shaped part forming result physical map;

[0035] Figure 13 For the split die position size map of the upper die and the side die in the comparative example one;

[0036] Figure 14 For the upper die, the lower die and the side die in the comparative example one in the up-down direction load change curve, 4 is the upper die, 5 is the lower die, 6 is the side die;

[0037] Figure 15 For the split die position size map of the upper die and the side die in the comparative example two;

[0038] Figure 16 For the comparative example two Ω-shaped part forming finite element simulation result cross section, (a) is the forming result after step two 5, (b) is the forming result after step two 6;

[0039] Figure 17 For the comparative example three step two Ω-shaped part finite element simulation forming whole process side die side horizontal load change curve. DETAILED DESCRIPTION

[0040] Specific implementation one: a kind of multi-directional die forging and split-flow pressure reduction composite forming method of Ω-shaped part of the embodiment, it is carried out according to the following steps:

[0041] I. Die design:

[0042] According to the design of Ω-shaped part multi-directional die forging and split-flow pressure reduction composite forming die;

[0043] The Ω-shaped part is composed of U-shaped curved web, flange and Ω-shaped reinforcing rib, the flange is arranged on both sides of the opening of the U-shaped curved web, and a plurality of Ω-shaped reinforcing ribs are uniformly arranged along the outer surfaces of the U-shaped curved web and the flange;

[0044] The multi-directional die forging and split-flow pressure reduction composite forming die is composed of an upper pad 1, a lower pad 2, a pair of side pads 3, an upper die 4, a lower die 5, a pair of side dies 6, a lower top block 7, a pair of side pads 8 and a lower die pressing plate 9; the lower top block 7 is arranged in the middle of the lower die 5, the punch of the upper die 4, the lower die 5, a pair of side dies 6 and the lower top block 7 form an Ω-shaped part cavity, and the flange cavity is located on a pair of side dies 6, and the Ω-shaped reinforcing rib cavity is located on the lower die 5, a pair of side dies 6 and the lower top block 7;

[0045] The upper mold 4 and a pair of side molds 6 part on the upper surface of the flange of the Ω-shaped part, with the parting surface parallel to the movement direction of the upper mold 4; let B be the vertical distance from the parting surface to the deepest part of the flange cavity of the side molds 6. 6f Let B be the vertical distance from the surface of the U-shaped curved web cavity of the lateral mold 6 to the deepest point of the flange cavity. 6w B 6f :B 6w =(0.5~0.9):1;

[0046] A pair of side molds 6 are provided with guide blocks 61 at both ends of the Ω-shaped part along the length direction, and the lower mold 5 is provided with guide grooves 51 at the corresponding positions of the guide blocks 61; the lower mold 5 is provided with a pressure plate groove 52 at the middle position of the upper surface of the front and rear side walls of the cavity along the length direction of the Ω-shaped part, and the pressure plate groove 52 is used to place the lower mold pressure plate 9.

[0047] II. Shaping:

[0048] ① Lubricate and heat the aluminum alloy billet and the multi-directional forging and split-flow pressure reduction composite forming die;

[0049] ② Open a pair of side molds 6, place the heated aluminum alloy billet into the cavity formed by the lower mold 5 and the lower top block 7, and press the upper mold 4 down into place at a speed v1;

[0050] ③ A pair of side molds 6 are fed at a speed of v2 until the load on the side pressure cylinder of the press is (0.7~0.9)F6, where F6 is the maximum load limit of the side pressure cylinder of the press;

[0051] ④ The pair of side dies 6 retract to a state of no lateral load, the upper die 4 is raised, and the lower die platen 9 is placed in the pressure plate groove 52. The upper die 4 is pressed down until the lower surface of the front and rear end side walls of the punch of the upper die 4 along the length of the Ω-shaped part contacts the lower die platen 9. At this time, the vertical distance between the lower end of the punch of the upper die 4 and the upper surface of the bottom of the formed part is h, and the load of the upper pressure cylinder of the press is ≤0.5F. t And ≥0.3F6, the F t This is the maximum load limit of the upper pressure cylinder of the press;

[0052] ⑤ The pair of side molds 6 continue to be fed at a speed of v2 until the load on the side pressure cylinder of the press is (0.7~0.9)F6;

[0053] ⑥ When the pair of side dies 6 retract to a distance b between the vertical distance between the U-shaped curved sidewall surface of the formed part and the U-shaped curved web cavity sidewall surface of the side die 6, lift the upper die 4, remove the lower die platen 9, and then continue to press down at a speed v1 until the load on the upper pressure cylinder of the press reaches (0.7~0.9)F. tOr lateral pressure cylinder load reaches (0.7-0.9) F6, set ⑤ complete after forming U-shaped side wall of the wall thickness T, b = (0.05-0.15) T;

[0054] ⑦ upper die 4 and a pair of lateral die 6 back, the lower ejector 7 will be formed out, that is, complete a kind of Ω-shaped piece multi-directional die forging and flow pressure reduction composite forming method.

[0055] The beneficial effects of the embodiment are:

[0056] The embodiment is aimed at the problem of high forming load and large die bias force of Ω-shaped piece multi-directional die forging, and a multi-directional die forging and flow pressure reduction composite forming method is designed. When the lateral die forming load approaches the maximum value, the upper die is lifted to a certain height, so that a gap is formed between the upper die and the formed piece. Then the lateral continues to load, and part of the deformed metal fills the flange and the rib, and the other part flows to the gap between the upper die and the formed piece, achieving the effect of flow pressure reduction and reducing the lateral forming pressure. Then, when the lateral load reaches a specified value again, the lateral die is retracted a small distance, so that a gap is formed between the formed piece and the lateral die. The upper die continues to press down, and part of the metal entering the gap between the upper die and the formed piece is pressed into the gap between the formed piece and the lateral die, and the other part continues to fill the flange and the rib, again producing the effect of flow pressure reduction and further improving the filling quality.

[0057] In the embodiment, the side pads below the lateral die are fixed on the lower pad plate, which can support the lateral die and effectively offset the downward bias load of the lateral die. To solve the problem of large upward bias force of the Ω-shaped piece multi-directional die forging die, a parting method of the upper die and the lateral die is designed to reduce the area difference of the upper and lower surfaces of the flange cavity of the lateral die in the vertical direction and reduce the bias force. At the same time, guide blocks and guide grooves are arranged on the lateral die and the lower die respectively. During lateral forming, the guide blocks are inserted into the guide grooves, and the upward bias force is borne by the guide blocks and the guide grooves, avoiding the damage of the lateral die root and the bolts directly bearing excessive bending moment. Before the upper die is lifted and the lateral die continues to feed, a lower die pressing plate is added between the upper and lower dies, and the upper die exerts a certain pressure on the lower die pressing plate, avoiding the bias of the two lateral dies with different tonnages acting on the upper die without load when the lateral die feeds, which leads to excessive bending moment of the upper die and the upper die bolts and damages them.

[0058] The difference between the embodiment and the first embodiment is that the upper pad plate 1 in step one is arranged on the upper end of the upper die 4, the lower pad plate 2 in step one is arranged on the lower end of the lower die 5, and the pair of side pads 3 in step one is arranged on the outer side of the pair of lateral dies 6. The pair of side pads 8 is arranged between the lower pad plate 2 and the pair of lateral dies 6. The rest is the same as the first embodiment.

[0059] Specific embodiment three: the difference between this embodiment and one of the specific embodiments one or two is that: the maximum width of the Ω-shaped part along the width direction of the U-shaped opening in step one is B1, the maximum height of the Ω-shaped part along the height direction of the U-shaped opening is H1, and the maximum width of the U-shaped opening of the Ω-shaped part is B 1U ; the B1:H1=(0.3-2):1, and the B 1U :B1=(0.4-0.8):1. The others are the same as the specific embodiment one or two.

[0060] Specific embodiment four: the difference between this embodiment and one of the specific embodiments one to three is that: the height of the guide block 61 in step one is H 61 , the length is L 61 , the unidirectional tensile yield strength of the mold material of a pair of side molds 6 in step one at the forging forming temperature is σ6, H 61 ×L 61 ×σ6≥0.2F6, wherein the unit of H 61 is mm, the unit of L 61 is mm, the unit of σ6 is MPa, and the unit of F6 is N. The others are the same as the specific embodiments one to three.

[0061] Specific embodiment five: the difference between this embodiment and one of the specific embodiments one to four is that: the depth of the guide groove 51 in step one is D 51 , D 51 ≥L 61 +0.5mm. The others are the same as the specific embodiments one to four.

[0062] Specific embodiment six: the difference between this embodiment and one of the specific embodiments one to five is that: the length of the lower mold pressing plate 9 in step one is L b , the width is B b , the unidirectional tensile yield strength of the material of the lower mold pressing plate 9 at room temperature is σ Lb , L b ×B b ×σ Lb ≥0.5F t , wherein the unit of L b is mm, the unit of B b is mm, the unit of σ Lb is MPa, and the unit of F t is N. The others are the same as the specific embodiments one to five.

[0063] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that: in step two, the aluminum alloy blank and the multi-directional die forging and pressure reduction composite forming die are lubricated and heated to 420-480℃. The others are the same as the specific embodiments one to six.

[0064] Specific embodiment eight: this embodiment is different from one of the specific embodiments one to seven in that: in step two ④, h = (0.02-0.2) H1. The others are the same as specific embodiments one to seven.

[0065] Specific embodiment nine: this embodiment is different from one of the specific embodiments one to eight in that: in step two ② and ⑥, v1 = 0.1 mm / s-3 mm / s. The others are the same as specific embodiments one to eight.

[0066] Specific embodiment ten: this embodiment is different from one of the specific embodiments one to nine in that: in step two ③ and ⑤, v2 = 0.1 mm / s-1 mm / s. The others are the same as specific embodiments one to nine.

[0067] The beneficial effects of the present application are verified by the following examples:

[0068] Example one, combined Figures 1 to 12 :

[0069] A multi-directional die forging and split-flow pressure reduction composite forming method of an Ω-shaped piece, which is carried out according to the following steps:

[0070] I. Die design:

[0071] Design a multi-directional die forging and split-flow pressure reduction composite forming die according to the Ω-shaped piece;

[0072] The Ω-shaped piece is composed of a U-shaped curved web, a flange, and an Ω-shaped reinforcing rib, the flange is arranged on both sides of the opening of the U-shaped curved web, and a plurality of Ω-shaped reinforcing ribs are uniformly arranged along the outer surfaces of the U-shaped curved web and the flange;

[0073] The multi-directional die forging and split-flow pressure reduction composite forming die is composed of an upper pad 1, a lower pad 2, a pair of side pads 3, an upper die 4, a lower die 5, a pair of side dies 6, a lower ejector block 7, a pair of side pads 8, and a lower die pressing plate 9; the lower ejector block 7 is arranged in the middle of the lower die 5, the punch of the upper die 4, the lower die 5, the pair of side dies 6, and the lower ejector block 7 form an Ω-shaped piece cavity, and the flange cavity is located on the pair of side dies 6, and the Ω-shaped reinforcing rib cavity is located on the lower die 5, the pair of side dies 6, and the lower ejector block 7;

[0074] The upper die 4 and the pair of side dies 6 are split on the upper surface of the flange of the Ω-shaped piece, and the split surface is parallel to the movement direction of the upper die 4; the vertical distance from the split surface to the deepest part of the flange cavity of the side die 6 is B 6f , B 6f = 72 mm, the vertical distance from the surface of the U-shaped curved web cavity of the side die 6 to the deepest part of the flange cavity is B 6w , B 6w = 110 mm, B 6f : B 6w= 0.65:1;

[0075] A pair of lateral dies 6 are provided with guide blocks 61 at both ends along the length direction of the Ω-shaped piece, and the lower die 5 is provided with guide grooves 51 at the corresponding positions of the guide blocks 61; the lower die 5 is provided with a press plate groove 52 at the middle position of the upper surface of the side wall at both ends along the length direction of the Ω-shaped piece, and the press plate groove 52 is used for placing the lower die press plate 9;

[0076] II. Forming:

[0077] ① The 2A12 aluminum alloy blank and the multi-directional die forging and split-flow pressure reduction composite forming die are lubricated and heated;

[0078] ② The pair of lateral dies 6 are opened, and the heated aluminum alloy blank is placed in the cavity formed by the lower die 5 and the lower ejector block 7, and the upper die 4 is pressed down to the position at a speed of 1 mm / s;

[0079] ③ The pair of lateral dies 6 are fed at a speed of 0.3 mm / s until the load of the lateral pressure cylinder of the press is 0.83F6, wherein F6 is the maximum load limit of the lateral pressure cylinder of the press, F6 = 3 × 10 7 N;

[0080] ④ The pair of lateral dies 6 are retracted to the lateral no-load state, the upper die 4 is lifted, the lower die press plate 9 is placed in the press plate groove 52, and the upper die 4 is pressed down until the lower surface of the punch at both ends along the length direction of the Ω-shaped piece of the upper die 4 contacts the lower die press plate 9, at this time, the vertical distance between the lower end of the punch of the upper die 4 and the upper surface of the bottom of the formed piece is h, and the load of the upper pressure cylinder of the press is 0.3F t 6 and 0.6F6, wherein F t 6 is the maximum load limit of the upper pressure cylinder of the press, F t 6 = 6 × 10 7 N;

[0081] ⑤ The pair of lateral dies 6 continue to be fed at a speed of 0.3 mm / s until the load of the lateral pressure cylinder of the press is 0.83F6;

[0082] ⑥ The pair of lateral dies 6 are retracted to the vertical distance b between the U-shaped curved side wall surface of the formed piece and the U-shaped curved web cavity side wall surface of the lateral die 6, b = 3 mm, the upper die 4 is lifted, the lower die press plate 9 is taken out, and then the upper die 4 continues to be pressed down at a speed of 1 mm / s until the load of the lateral pressure cylinder of the press reaches 0.83F6, wherein T is the wall thickness of the U-shaped side wall of the formed piece after step ⑤ is completed, T = 22 mm, and b = 0.14T = 3 mm;

[0083] ⑦ The upper die 4 and the pair of lateral dies 6 are retracted, the formed piece is ejected by the lower ejector block 7, and the multi-directional die forging and split-flow pressure reduction composite forming method of the Ω-shaped piece is completed.

[0084] The upper pad 1 mentioned in step one is set on the upper end of the upper mold 4; the lower pad 2 mentioned in step one is set on the lower end of the lower mold 5; the pair of side pads 3 mentioned in step one are set on the outside of the pair of side molds 6; the pair of side pads 8 are set between the lower pad 2 and the pair of side molds 6.

[0085] In step one, let the maximum width of the Ω-shaped component along the width direction of the U-shaped opening be B1, where B1 = 536 mm; let the maximum height of the Ω-shaped component along the height direction of the U-shaped opening be H1, where H1 = 412 mm; and let the maximum width of the U-shaped opening of the Ω-shaped component be B... 1U B 1U =284mm; the B1:H1 = 1.3:1, the B 1U :B1=0.53:1.

[0086] Let the height of guide block 61 in step one be H. 61 H 61 =100mm, length is L 61 L 61 =127mm, the material of the pair of side dies 6 is 5CrNiMo, and the uniaxial tensile yield strength of the material of the pair of side dies 6 in step one at the forming temperature of 440℃ for 2A12 aluminum alloy forging is σ6, σ6=900MPa, H 61 ×L 61 ×σ6=0.381F6, where H 61 The unit is mm, L 61 The unit is mm, the unit of σ6 is MPa, and the unit of F6 is N.

[0087] Let the depth of the guide groove 51 in step one be D. 51 D 51 =130mm, D 51 =L 61 +3mm.

[0088] Let the length of the lower mold plate 9 in step one be L. b L b =210mm, width is B b B b =190mm, the material used for the lower mold plate 9 is 5CrNiMo, and the uniaxial tensile yield strength of the material of the lower mold plate 9 at room temperature is σ. Lb , σ Lb =1000MPa, L b ×B b ×σ Lb =0.665F t L b The unit is mm, B b The unit is mm, σLb F is in MPa, F t F is in N.

[0089] In step two ①, the aluminum alloy blank and the multi-directional die forging and split-flow pressure-reducing combined forming die were lubricated and heated to 440℃.

[0090] In step two ④, h = 0.097H1 = 40mm.

[0091] Comparative Example One, combined with Figures 13 to 14 The difference between this comparative example and Example One is that the vertical distance from the parting surface to the deepest part of the flange cavity of the lateral die 6 is B 6f , and B 6f = 120mm, B 6f : B 6w = 1.09:1. The rest is the same as Example One.

[0092] Comparative Example Two, combined with Figures 15 to 16 The difference between this comparative example and Example One is that the vertical distance from the parting surface to the deepest part of the flange cavity of the lateral die 6 is B 6f , and B 6f = 21mm, B 6f : B 6w = 0.19:1. The rest is the same as Example One.

[0093] Comparative Example Three, combined with Figure 17 The difference between this comparative example and Example One is that in step two ③, the lateral die 6 is fed straight until the die cavity is completely filled, and steps ④ to ⑥ are cancelled. The rest is the same as Example One.

[0094] Figure 10 is the load change curve of the whole process of forming the Ω-shaped piece in Example One, step two, (a) is the lateral horizontal load change curve of the lateral die, (b) is the load change curve of the upper die, lower die and lateral die in the up-down direction, 4 is the upper die, 5 is the lower die, and 6 is the lateral die; if the load of the lower die is greater than that of the upper die, the lateral die is subjected to upward bias load. From Figure 10 (a), it can be seen that the maximum lateral load is about 2500t; from Figure 10 (b), it can be seen that the maximum upward bias load of the lateral die is about 55t.

[0095] Figure 12 is the physical map of the Ω-shaped piece formed in Example One; it can be seen that the Ω-shaped piece is well formed and has no surface defects.

[0096] Figure 14The load change curve of the upper die, the lower die and the lateral die in the up-down direction in the comparative example 1, 4 is the upper die, 5 is the lower die, and 6 is the lateral die; if the load of the lower die is greater than that of the upper die, the lateral die is subjected to the bias load in the upward direction. As shown in the figure, the maximum bias load of the lateral die in the upward direction is about 199 t, which is more than doubled compared with the first embodiment.

[0097] Figure 16 The cross-sectional view of the finite element simulation result of the Ω-shaped part forming in the comparative example 2, (a) is the forming result after step 2 (v), and (b) is the forming result after step 2 (vi). As shown in the figure, after step 2 (v), the flange of the formed part is upwardly buckled due to the excessive space above the flange, and a gap is generated on the lower surface of the flange, as shown in the circle in (a); this part of the gap still cannot be completely pressed after forming in step 2 (vi), as shown in the circle in (b). Figure 16 Figure 16

[0098] Figure 17 The lateral horizontal load change curve of the lateral die in the whole forming process of the step 2 Ω-shaped part in the comparative example 3; as shown in the figure, the maximum load of the lateral die reaches about 4400 t = 40000 kN, which is more than 75% larger than that in the first embodiment, and has exceeded the maximum load of the lateral pressure cylinder of the press.​​

Claims

1. A multi-directional die forging and split-flow pressure reduction composite forming method for Ω-shaped parts, characterized in that... It is done in the following steps: I. Mold Design: Design a multi-directional die forging and split-flow pressure reduction composite forming mold based on Ω-shaped parts; The Ω-shaped component consists of a U-shaped curved web, a flange, and Ω-shaped reinforcing ribs. Flanges are provided on both sides of the opening of the U-shaped curved web, and multiple Ω-shaped reinforcing ribs are evenly distributed along the outer surface of the U-shaped curved web and the flanges. The multi-directional forging and diversion pressure reduction composite forming mold consists of an upper pad (1), a lower pad (2), a pair of side pads (3), an upper mold (4), a lower mold (5), a pair of side molds (6), a lower ejector block (7), a pair of side pads (8), and a lower mold pressure plate (9); the lower ejector block (7) is located in the middle of the lower mold (5), and the punch of the upper mold (4), the lower mold (5), the pair of side molds (6), and the lower ejector block (7) together form an Ω-shaped part cavity, and the flange cavity is located on the pair of side molds (6), and the Ω-shaped reinforcing rib cavity is located on the lower mold (5), the pair of side molds (6), and the lower ejector block (7); The upper mold (4) and a pair of side molds (6) are used for parting on the upper surface of the flange of the Ω-shaped part, with the parting surface parallel to the direction of movement of the upper mold (4); let B be the vertical distance from the parting surface to the deepest part of the flange cavity of the side molds (6). 6f Let B be the vertical distance from the surface of the U-shaped curved web cavity of the lateral mold (6) to the deepest part of the flange cavity. 6w B 6f :B 6w =(0.5~0.9):1; A pair of side molds (6) are provided with guide blocks (61) at both ends of the Ω-shaped part along the length direction, and the lower mold (5) is provided with guide grooves (51) at the corresponding positions of the guide blocks (61); the lower mold (5) is provided with a pressure plate groove (52) at the middle position of the upper surface of the front and rear side walls of the cavity along the length direction of the Ω-shaped part, and the pressure plate groove (52) is used to place the lower mold pressure plate (9); II. Shaping: ① Lubricate and heat the aluminum alloy billet and the multi-directional forging and split-flow pressure reduction composite forming die; ② Open a pair of side molds (6), place the heated aluminum alloy blank in the cavity formed by the lower mold (5) and the lower top block (7), and press the upper mold (4) down to the position at a speed v1; ③ A pair of side molds (6) are fed at a speed of v2 until the load on the side pressure cylinder of the press is (0.7~0.9)F6, where F6 is the maximum load limit of the side pressure cylinder of the press; ④ The pair of side dies (6) retract to a state of no lateral load, the upper die (4) is raised, and the lower die platen (9) is placed in the pressure plate groove (52). The upper die (4) is pressed down until the lower surface of the front and rear end side walls of the punch of the upper die (4) along the length of the Ω-shaped part contacts the lower die platen (9). At this time, the vertical distance between the lower end of the punch of the upper die (4) and the upper surface of the bottom of the formed part is h, and the load of the upper pressure cylinder of the press is ≤0.5F. t And ≥0.3F6, the F t This is the maximum load limit of the upper pressure cylinder of the press; ⑤ The pair of side molds (6) continue to feed at a speed of v2 until the load on the side pressure cylinder of the press is (0.7~0.9)F6; ⑥ When the pair of side dies (6) retract to a point where the vertical distance between the U-shaped curved sidewall surface of the formed part and the U-shaped curved web cavity sidewall surface of the side die (6) is b, lift the upper die (4), remove the lower die platen (9), and then continue to press down the upper die (4) at a speed v1 until the load on the upper pressure cylinder of the press reaches (0.7~0.9)F. t Or the lateral pressure cylinder load reaches (0.7~0.9)F6, and let the wall thickness of the U-shaped sidewall of the formed part after ⑤ be T, b=(0.05~0.15)T; ⑦ The upper die (4) and a pair of side dies (6) return, and the lower ejector block (7) ejects the formed part, thus completing a multi-directional die forging and diversion pressure reduction composite forming method for an Ω-shaped part.

2. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... The upper pad (1) mentioned in step one is set at the upper end of the upper mold (4); the lower pad (2) mentioned in step one is set at the lower end of the lower mold (5); the pair of side pads (3) mentioned in step one are set outside the pair of side molds (6); the pair of side pads (8) are set between the lower pad (2) and the pair of side molds (6).

3. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... In step one, let the maximum width of the Ω-shaped component along the width direction of the U-shaped opening be B1, the maximum height of the Ω-shaped component along the height direction of the U-shaped opening be H1, and the maximum width of the U-shaped opening of the Ω-shaped component be B. 1U The B1:H1 = (0.3~2):1, the B 1U :B1=(0.4~0.8):

1.

4. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that: In step one, the height of the guide block (61) is H. 61 The length is L 61 Let the uniaxial tensile yield strength of the die material of the pair of side dies (6) in step one at the forging forming temperature be σ6, H 61 ×L 61 ×σ6≥0.2F6, where H 61 The unit is mm, L 61 The unit is mm, the unit of σ6 is MPa, and the unit of F6 is N.

5. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 4, characterized in that... Let the depth of the guide groove (51) in step one be D. 51 D 51 ≥L 61 +0.5mm.

6. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... Let the length of the lower mold plate (9) in step one be L. b Width is B b Let the uniaxial tensile yield strength of the material of the molded plate (9) at room temperature be σ. Lb L b ×B b ×σ Lb ≥0.5F t L b The unit is mm, B b The unit is mm, σ Lb The unit is MPa, F t The unit is N.

7. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... In step 2①, the aluminum alloy billet and the multi-directional forging and diversion pressure reduction composite forming die are lubricated and heated to 420℃~480℃.

8. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... In step 2, h = (0.02~0.2)H1.

9. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... In steps 2 and 6, v1 = 0.1 mm / s ~ 3 mm / s.

10. The multi-directional die forging and split-flow pressure reduction composite forming method for an Ω-shaped part according to claim 1, characterized in that... In steps 2, ③ and ⑤, v2 = 0.1 mm / s ~ 1 mm / s.

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