Preform design method and forging method for large-size variable-section Ω-shaped parts

Abstract

The present invention relates to a preform design method and a forging forming method for large-sized variable-section Ω-shaped parts, and belongs to the field of forging. The present invention solves the problem of difficulty and high cost in the processing and manufacturing of existing large-sized variable-section Ω-shaped parts. Method: 1. Construct a half model of the Ω-shaped part along the symmetry plane D in the length direction of the Ω-shaped part; 2. Draw the longitudinal section profile of the web of the preform; 3. Design a half model of the web of the preform; 4. Design a half model of the web-flange of the preform; 5. Design a half model of the preform; 6. Mirror. Forging forming method: Prepare a preform according to the preform model, place the preform with the opening downward on the lower die, and then press the upper die into the next step for forming. The present invention is used for the preform design method and forging forming of large-sized variable-section Ω-shaped parts.

Description

Technical Field

[0001] The invention belongs to the field of forging. Background Art

[0002] In order to achieve faster flight speeds, longer ranges and lower energy consumption, aerospace vehicles are increasingly moving towards lightweight design and integrated manufacturing. Lightweight design makes the structure of parts more and more complex, while integrated manufacturing increases the size of components and increases the difficulty of processing and manufacturing. Large-size variable-section Ω-shaped parts are a key load-bearing component of spacecraft. Their cross-section is mainly composed of U-shaped or V-shaped webs and flanges on both sides of the webs. The cross-sectional shape and size change continuously along the length direction, and the configuration is relatively complex. Direct mechanical processing will cause a large amount of material and labor time consumption, and the cost is extremely high; the complex deep cavity with flange configuration also makes it difficult to control the generation of defects in ordinary forging, and due to the large overall size of the component, the load requirements of large deformation forging are also difficult to meet. Summary of the invention

[0003] The present invention aims to solve the problems of difficulty and high cost in the processing and manufacturing of existing large-sized variable-section Ω-shaped parts, and further provides a preform design method and a forging forming method for large-sized variable-section Ω-shaped parts.

[0004] The preform design method of large-size variable-section Ω-shaped parts is carried out according to the following steps:

[0005] 1. In the 3D modeling software, a half model of the Ω-shaped part is constructed along the symmetry plane D in the length direction of the Ω-shaped part;

[0006] The Ω-shaped piece is a large-sized, bilaterally symmetrical variable-section Ω-shaped structure, and the Ω-shaped piece is composed of a forged web and a forged flange. Forged flanges are arranged on both sides of the opening of the forged web, and forged fillets are arranged at the connection between the forged web and the forged flange. The maximum width of the Ω-shaped piece along the opening width direction is B1, and B1 of different cross sections in the vertical length direction of the Ω-shaped piece is the same, and the side surface F of the forged flange along the length direction of the Ω-shaped piece is a plane, and the upper edge of the side surface F is located on the same straight line K;

[0007] The forging web is one of U-shaped and V-shaped or a combination of the two. When it is U-shaped, the straight wall portion of the forging web is parallel to the symmetry plane D, and when it is V-shaped, there is an angle between the straight wall portion of the forging web and the symmetry plane D.

[0008] 2. In the 3D modeling software, set a plane E on the Ω-shaped half model. Plane E is perpendicular to the symmetry plane D. Plane E divides the Ω-shaped half model into part I, which is mainly composed of the forging web, and part II, which is mainly composed of the forging flange. Set the vertical distance between plane E and straight line K to be B. E , assuming that the maximum radius of the forging corner of the Ω-shaped part is (R 13 )max , B E :(R 13 ) max =(0.5-1):1, then draw the longitudinal section profile of the web of the preform on plane E; the longitudinal section profile of the web of the preform covers the section profile of the half model of the Ω-shaped part on plane E;

[0009] Assume that the cross-sectional thickness of the Ω-shaped half model on plane E is T 1E , assuming that the thickness of the longitudinal section profile of the preform web is T 2E , then at the same position, T 1E :T 2E =(0.6~1):1; let the distance between the thickness center line of the cross-section profile of the Ω-shaped half model on plane E and the thickness center line of the longitudinal cross-section profile of the web of the preform be H 12 , then at the same position, H 12 :T 1E =(0~0.2):1;

[0010] 3. In the 3D modeling software, the longitudinal section profile of the web of the preform is subjected to unidirectional stretching bosses in a direction perpendicular to the length direction to obtain a half model of the web of the preform;

[0011] Assume that the width of the prefabricated web half model is B 21 , assuming that the cross-sectional area of ​​the prefabricated web half model perpendicular to the length direction is S 21 , let the cross-sectional area of ​​the Ω-shaped half model part I perpendicular to the length direction be S Ⅰ , then at the same section perpendicular to the length direction, S 21 =(1.1~1.4)S Ⅰ ;

[0012] Fourth, in the three-dimensional modeling software, a plane G is set above the edge along the length direction of the preform web half model, and the preform flange profile is drawn on the plane G. The preform flange profile is stretched along the direction perpendicular to the length direction and parallel to the plane E until the preform flange model and the bottom surface of the preform web half model are coplanar, and then according to the angle between the straight wall part of the forging web of the V-shaped part and the symmetry plane D, the co-bottom surface of the preform flange model and the preform web half model is cut off at the corresponding position to form an incision, so as to obtain the preform web-flange half model;

[0013] Assume that the cross-sectional area of ​​the preform flange model perpendicular to the length direction is S 22 ; Assume that the distance from the symmetry plane D of the Ω-shaped half model to the outer edge of the forging fillet is B R , B 21 ≥B R ;

[0014] 5. In the 3D modeling software, a preform fillet is added between the preform flange model and the preform web half model to obtain a preform half model;

[0015] Assume that the fillet radius of the preform is R 23 , R 23 >(R 13 ) max ;

[0016] Assume that the cross-sectional area of ​​the preform fillet perpendicular to the length direction is S 23 , let the width of the preform half model be B3, let the cross-sectional area of ​​the Ω-shaped half model part II perpendicular to the length direction be S Ⅱ , then at the same section perpendicular to the length direction, S 22 +S 23 =(1.0~1.3)S Ⅱ ;

[0017] Assume the thickness of the prefabricated web half model is T 21 , let the total arc length of the inner wall of the Ω-shaped half model be Assume that the total arc length of the outer wall of the Ω-shaped half model is Assume that the fillet radius of the Ω-shaped forging is R 13 , then in the same section perpendicular to the length direction, when R 13 >T 21 hour, When R 13 <T 21 hour,

[0018] 6. In the three-dimensional modeling software, the preform half model is mirrored with plane E as the symmetry plane to obtain the preform model, thus completing the design method of the large-size variable-section Ω-shaped part preform.

[0019] The method for forging an Ω-shaped part using a preform is carried out in the following steps:

[0020] A preform is prepared according to the preform model, the preform is placed on the lower die with its opening downward, and then the upper die is pressed to form a next step, thus completing the method of forging an Ω-shaped part using the preform.

[0021] The beneficial effects of the present invention are:

[0022] In view of the difficulty in forming large-sized variable-section Ω-shaped parts by large plastic deformation, the present invention proposes a bending forging forming process for straight web with flange preforms. During the forming process, the web of the preform only undergoes bending deformation and a small amount of thinning. The preform flanges on both sides of the web of the preform are first bent and then undergo a large upsetting deformation, which greatly reduces the forming load of the forging. At the same time, it avoids the problem of difficulty in gathering materials at the flange due to the complexity of the forging shape during conventional large plastic deformation forming, greatly reducing the forming difficulty. The present invention provides a specific design method for the preform, especially involving the determination of key dimensions, to ensure that in the bending forging process, there will be no situation where the filling is not fully filled due to inadequate bending. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The Ω-shaped piece described in step 1 of embodiment 1, (a) is a visual view of the convex surface, 11 is a forging web, 12 is a forging flange, 13 is a forging fillet, (b) is a visual view of the concave surface, and (c) is a side view, wherein sections A, B, and C are perpendicular to the symmetry plane D;

[0024] Figure 2 The preform model obtained in step 6 of Example 1, (a) is a front intuitive view, 21 is a preform web half model, 22 is a preform flange model, 23 is a preform fillet model, (b) is a back intuitive view;

[0025] Figure 3 Schematic diagram of the preform forging method in Example 1, 1 is an Ω-shaped part, 2 is a preform, 3 is a lower die, and 4 is an upper die;

[0026] Figure 4 2 is a design flow chart of the preform in Example 1, (a) is a front intuitive view of the preform web half model in step three, 21 is a preform web half model, (b) is a front intuitive view of the coplanar bottom surface of the preform flange model and the preform web half model in step four, 22 is the preform flange model, (c) is the corresponding position of the co-bottom surface of the preform flange model and the preform web half model in step four, (d) is a front intuitive view of the preform half model in step five, 23 is a preform fillet model, (e) is a front intuitive view of the preform model in step six, (f) is Figure 4 (a) is the bottom surface intuitive diagram, (g) is Figure 4 (b) is the bottom surface intuitive diagram, (h) is Figure 4 (c) is the bottom surface intuitive diagram, (i) is Figure 4 (d) is the bottom surface intuitive diagram, (j) is Figure 4 (e) Bottom surface intuitive diagram;

[0027] Figure 5 Schematic diagram of the position of plane E in step 2 of embodiment 1, (a) is an intuitive diagram, and (b) is a main view;

[0028] Figure 6 The longitudinal section profile size design diagram of the web of the preform in step 2 of Example 1, (a) is the complete profile, 14 is the cross-sectional profile of the half model of the Ω-shaped part on plane E, 24 is the longitudinal section profile of the web of the preform, and (b) is Figure 6 (a) is a partial enlarged view of the dotted box, 15 is the thickness centerline of the cross-section profile of the Ω-shaped half model on plane E, and 25 is the thickness centerline of the longitudinal cross-section profile of the web of the preform;

[0029] Figure 7 The flange outline dimension design diagram in step 4 of embodiment 1, (a) is the prefabricated blank web-flange half model, (b) is the Ω-shaped part half model part II, where C is Figure 1 Middle section C;

[0030] Figure 8 The cross-sectional dimensions of the Ω-shaped member in step 1 of embodiment 1 and the preform half model in step 5, (a) and (d) are Figure 1 The cross-section A, (b) and (e) of the Ω-shaped piece are Figure 1 The cross-sections B, (c) and (f) of the Ω-shaped member are Figure 1 Section C of the Ω-shaped part, (a), (b) and (c) are the Ω-shaped part in step 1 of embodiment 1, (d), (e) and (f) are the preform half models in step 5, 21 is the preform web half model, 22 is the preform flange model, and 23 is the preform fillet model;

[0031] Fig. 9 For example, the Ω-shaped half model is Figure 1 (c) Finite element simulation of the bending forging forming process at section C, (a) is the initial state, (b) is the intermediate step, (c) is the inner surface of the flange of the formed part contacts the inner surface of the upper mold cavity, (d) is the upper surface of the flange of the formed part contacts the upper surface of the upper mold cavity, and (e) is the final result;

[0032] Fig.10 This is a finite element simulation formed part of a large-sized variable-section Ω-shaped part prepared in Example 1, (a) is a direct view of the convex surface, and (b) is a direct view of the concave surface;

[0033] Fig.11 The preform half model in step 5 of comparative example 1 is Figure 1 Dimensional drawing of the section C of the middle Ω-shaped part, 21 is the preform web half model, 22 is the preform flange model, and 23 is the preform fillet model;

[0034] Fig.12 For the comparative example, a half-model of an Ω-shaped part is Figure 1(c) Finite element simulation of the bending forging forming process at section C, (a) is the initial state, (b) is the intermediate step, (c) is the upper surface of the flange of the formed part contacts the upper surface of the upper mold cavity, and (d) is the final result. DETAILED DESCRIPTION

[0035] Specific implementation method 1: The design method of the large-size variable-section Ω-shaped preform of this implementation method is carried out according to the following steps:

[0036] 1. In the 3D modeling software, a half model of the Ω-shaped part is constructed along the symmetry plane D in the length direction of the Ω-shaped part;

[0037] The Ω-shaped piece is a large-sized, bilaterally symmetrical variable-section Ω-shaped structure, and the Ω-shaped piece is composed of a forged web and a forged flange. Forged flanges are arranged on both sides of the opening of the forged web, and forged fillets are arranged at the connection between the forged web and the forged flange. The maximum width of the Ω-shaped piece along the opening width direction is B1, and B1 of different cross sections in the vertical length direction of the Ω-shaped piece is the same, and the side surface F of the forged flange along the length direction of the Ω-shaped piece is a plane, and the upper edge of the side surface F is located on the same straight line K;

[0038] The forging web is one of U-shaped and V-shaped or a combination of the two. When it is U-shaped, the straight wall portion of the forging web is parallel to the symmetry plane D, and when it is V-shaped, there is an angle between the straight wall portion of the forging web and the symmetry plane D.

[0039] 2. In the 3D modeling software, set a plane E on the Ω-shaped half model. Plane E is perpendicular to the symmetry plane D. Plane E divides the Ω-shaped half model into part I, which is mainly composed of the forging web, and part II, which is mainly composed of the forging flange. Set the vertical distance between plane E and straight line K to be B. E , assuming that the maximum radius of the forging corner of the Ω-shaped part is (R 13 ) max , B E :(R 13 ) max =(0.5-1):1, then draw the longitudinal section profile of the web of the preform on plane E; the longitudinal section profile of the web of the preform covers the section profile of the half model of the Ω-shaped part on plane E;

[0040] Assume that the cross-sectional thickness of the Ω-shaped half model on plane E is T 1E , assuming that the thickness of the longitudinal section profile of the preform web is T 2E , then at the same position, T 1E :T 2E =(0.6~1):1; let the distance between the thickness center line of the cross-section profile of the Ω-shaped half model on plane E and the thickness center line of the longitudinal cross-section profile of the web of the preform be H 12 , then at the same position, H 12 :T1E =(0~0.2):1;

[0041] 3. In the 3D modeling software, the longitudinal section profile of the web of the preform is subjected to unidirectional stretching bosses in a direction perpendicular to the length direction to obtain a half model of the web of the preform;

[0042] Assume that the width of the prefabricated web half model is B 21 , assuming that the cross-sectional area of ​​the prefabricated web half model perpendicular to the length direction is S 21 , let the cross-sectional area of ​​the Ω-shaped half model part I perpendicular to the length direction be S Ⅰ , then at the same section perpendicular to the length direction, S 21 =(1.1~1.4)S Ⅰ ;

[0043] Fourth, in the three-dimensional modeling software, a plane G is set above the edge along the length direction of the preform web half model, and the preform flange profile is drawn on the plane G. The preform flange profile is stretched along the direction perpendicular to the length direction and parallel to the plane E until the preform flange model and the bottom surface of the preform web half model are coplanar, and then according to the angle between the straight wall part of the forging web of the V-shaped part and the symmetry plane D, the co-bottom surface of the preform flange model and the preform web half model is cut off at the corresponding position to form an incision, so as to obtain the preform web-flange half model;

[0044] Assume that the cross-sectional area of ​​the preform flange model perpendicular to the length direction is S 22 ; Assume that the distance from the symmetry plane D of the Ω-shaped half model to the outer edge of the forging fillet is B R , B 21 ≥B R ;

[0045] 5. In the 3D modeling software, a preform fillet is added between the preform flange model and the preform web half model to obtain a preform half model;

[0046] Assume that the fillet radius of the preform is R 23 , R 23 >(R 13 ) max ;

[0047] Assume that the cross-sectional area of ​​the preform fillet perpendicular to the length direction is S 23 , let the width of the preform half model be B3, let the cross-sectional area of ​​the Ω-shaped half model part II perpendicular to the length direction be S Ⅱ , then at the same section perpendicular to the length direction, S 22 +S 23 =(1.0~1.3)S Ⅱ ;

[0048] Assume the thickness of the prefabricated web half model is T 21 , let the total arc length of the inner wall of the Ω-shaped half model be Assume that the total arc length of the outer wall of the Ω-shaped half model is Assume that the fillet radius of the Ω-shaped forging is R 13 , then in the same section perpendicular to the length direction, when R 13 >T 21 hour, When R 13 <T 21 hour,

[0049] 6. In the three-dimensional modeling software, the preform half model is mirrored with plane E as the symmetry plane to obtain the preform model, thus completing the preform design method for large-size variable-section Ω-shaped parts.

[0050] The Ω-shaped member described in this specific embodiment has continuously changing shapes and dimensions at different cross sections of the member, except for its width.

[0051] The beneficial effects of this specific implementation are:

[0052] This specific implementation method aims at the problem of difficulty in forming large-sized variable-section Ω-shaped parts with large plastic deformation, and proposes a bending forging forming process for straight web with flange preform. During the forming process, the web of the preform only undergoes bending deformation and a small amount of thinning. The preform flanges on both sides of the web of the preform are first bent, and then undergo a large upsetting deformation, which greatly reduces the forming load of the forging; at the same time, it avoids the problem of difficulty in gathering materials at the flange due to the complexity of the forging shape during conventional large plastic deformation forming, greatly reducing the forming difficulty. The present invention provides a specific design method for the preform, especially involving the determination of key dimensions, to ensure that there will be no incomplete filling due to inadequate bending during the bending forging forming process.

[0053] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that: in step 1, the length of the Ω-shaped member is set to L1, and L1 ≥ 800 mm. The rest is the same as the specific implementation method 1.

[0054] Specific implementation method 3: This implementation method is different from specific implementation methods 1 or 2 in that: in step 1, the maximum height of the Ω-shaped member along the height direction of the U-shaped opening is set to (H1) max , B 1: (H1) max =(0.5-4): 1. The rest is the same as the first or second specific implementation.

[0055] Specific implementation method 4: This implementation method is different from the specific implementation methods 1 to 3 in that: in step 1, the minimum thickness of the forging web is set to (T 11 ) min , B 1: (T 11 ) min =(5-25): 1. The rest is the same as the first to third specific embodiments.

[0056] Specific embodiment 5: This embodiment is different from any one of the specific embodiments 1 to 4 in that: in step 4, the cross-sectional area of ​​the prefabricated web-flange half model perpendicular to the length direction is set to S2, then at the same cross section perpendicular to the length direction, S2=S 21 +S 22 ; Assume that the width of the preform web-flange half model is B2, and the width of the preform flange model is B 22 , then in the same section perpendicular to the length direction, B2=B 21 +B 22 The rest is the same as the specific implementation modes 1 to 4.

[0057] Specific embodiment 6: This embodiment is different from any one of the specific embodiments 1 to 5 in that: in step 5, the cross-sectional area of ​​the preform half model perpendicular to the length direction is set as S3, and the cross-sectional area of ​​the preform fillet perpendicular to the length direction is set as S 23 , then at the same section perpendicular to the length direction, S3=S 21 +S 22 +S 23 ; Assume that the width of the preform half model is B3, then in the same section perpendicular to the length direction, B2 = B3 = B 21 +B 22 The rest is the same as the specific implementation modes 1 to 5.

[0058] Specific embodiment 7: This embodiment differs from Specific embodiments 1 to 6 in that: in step 4, the V-shaped portion is such that the angle between the inner walls of the forging web on both sides and the symmetry plane D is θ1, and the angle between the cutout and the bottom surface of the preform web half model is θ2, then under the same cross section, θ2 = (0.7-1.3)θ1. The rest is the same as Specific embodiments 1 to 6.

[0059] Specific embodiment 8: This embodiment differs from any one of specific embodiments 1 to 7 in that: in step 4, the side surface F of the forged flange along the length direction of the Ω-shaped piece and the dihedral angle between the symmetric surface D of the Ω-shaped piece is set to θ FD , 0°≤θ FD ≤60°, let the dihedral angle between plane G and plane E be θ GE ,θGE =(90°-θ FD );Let the length of the intersection of the cross section perpendicular to the length direction of the Ω-shaped half model and the plane F in the middle of the Ω-shaped half model part II be B F , let the length of the intersection line between the cross section at the corresponding position of the preform flange model and the plane G of the preform flange model be B G , B G =(1~2.5)B F The rest is the same as Specific Implementation Methods 1 to 7.

[0060] Specific embodiment 9: This embodiment is different from specific embodiments 1 to 8 in that: the preform described in step 7 is a bilaterally symmetrical variable cross-section structure, the preform is composed of a preform web and a preform flange, the cross section of the preform web is rectangular, one-way raised preform flanges are arranged on both sides of the preform web along the thickness direction of the preform web, and a preform fillet is arranged at the connection between the preform web and the preform flange. The rest is the same as specific embodiments 1 to 8.

[0061] Specific embodiment 10: This embodiment uses a preform to forge an Ω-shaped part in the following steps:

[0062] A preform is prepared according to the preform model, the preform is placed on the lower die with its opening downward, and then the upper die is pressed to form a next step, thus completing the method of forging an Ω-shaped part using the preform.

[0063] During the process of this specific implementation, the web of the preform mainly undergoes bending deformation, with a small amount of thinning. In the later stage of forming, the flange of the preform contacts the upper surface of the upper mold cavity and undergoes upsetting deformation to complete the forming.

[0064] The following examples are used to verify the beneficial effects of the present invention:

[0065] Embodiment 1, combined with Figures 1 to 10 :

[0066] The design method of the large-size variable-section Ω-shaped preform is carried out according to the following steps:

[0067] 1. In the 3D modeling software, a half model of the Ω-shaped part is constructed along the symmetry plane D in the length direction of the Ω-shaped part;

[0068] The Ω-shaped piece is a large-sized, bilaterally symmetrical variable-section Ω-shaped structure, and the Ω-shaped piece is composed of a forged web and a forged flange. Forged flanges are arranged on both sides of the opening of the forged web, and forged fillets are arranged at the connection between the forged web and the forged flange. The maximum width of the Ω-shaped piece along the opening width direction is B1, B1=540mm, B1 of different cross sections in the vertical length direction of the Ω-shaped piece is the same, and the side surface F of the forged flange along the length direction of the Ω-shaped piece is a plane, and the upper edge of the side surface F is located on the same straight line K;

[0069] The forging web is a combination of a U-shape and a V-shape; when the forging web is in the U-shape, the straight wall portion in the forging web is parallel to the symmetry plane D, and when the forging web is in the V-shape, there is an angle between the straight wall portion in the forging web and the symmetry plane D;

[0070] 2. In the 3D modeling software, set a plane E on the Ω-shaped half model. Plane E is perpendicular to the symmetry plane D. Plane E divides the Ω-shaped half model into part I, which is mainly composed of the forging web, and part II, which is mainly composed of the forging flange. Set the vertical distance between plane E and straight line K to be B. E , B E =50mm, assuming the maximum radius of the forging corner of the Ω-shaped part is (R 13 ) max , (R 13 ) max =80mm, B E :(R 13 ) max =0.63:1, and then draw the longitudinal section profile of the web of the preform on plane E; the longitudinal section profile of the web of the preform covers the section profile of the Ω-shaped part half model on plane E;

[0071] Assume that the cross-sectional thickness of the Ω-shaped half model on plane E is T 1E , assuming that the thickness of the longitudinal section profile of the preform web is T 2E , then at the same position, any position meets T 1E :T 2E =(0.6~1):1; Figure 6 Taking the dotted line part in (b) as an example, T 1E =58mm, T 2E =87mm, T 1E :T 2E =0.67:1; let the distance between the thickness centerline of the cross-section profile of the Ω-shaped half model on plane E and the thickness centerline of the longitudinal cross-section profile of the web of the preform be H 12 , then at the same position, any position meets H 12 :T 1E =(0~0.2):1, Figure 6 Taking the dotted line part in (b) as an example, H 12 =8.5mm, H12 :T 1E =0.15:1;

[0072] 3. In the 3D modeling software, the longitudinal section profile of the web of the preform is subjected to unidirectional stretching bosses in a direction perpendicular to the length direction to obtain a half model of the web of the preform;

[0073] Assume that the width of the prefabricated web half model is B 21 , assuming that the cross-sectional area of ​​the prefabricated web half model perpendicular to the length direction is S 21 , let the cross-sectional area of ​​the Ω-shaped half model part I perpendicular to the length direction be S Ⅰ , then in the same cross section perpendicular to the length direction, any position meets S 21 =(1.1~1.4)S Ⅰ ,by Figure 8 (a)(d) as an example, S 21 =23436mm 2 , S Ⅰ =18000mm 2 , S 21 =1.30S Ⅰ ;

[0074] Fourth, in the three-dimensional modeling software, a plane G is set above the edge along the length direction of the preform web half model, and the preform flange profile is drawn on the plane G. The preform flange profile is stretched along the direction perpendicular to the length direction and parallel to the plane E until the preform flange model and the bottom surface of the preform web half model are coplanar, and then according to the angle between the straight wall part of the forging web of the V-shaped part and the symmetry plane D, the co-bottom surface of the preform flange model and the preform web half model is cut off at the corresponding position to form an incision, so as to obtain the preform web-flange half model;

[0075] Assume that the cross-sectional area of ​​the preform web-flange half model perpendicular to the length direction is S2, and the cross-sectional area of ​​the preform flange model perpendicular to the length direction is S 22 , then in the same cross section perpendicular to the length direction, any position satisfies S2=S 21 +S 22 ; Assume that the width of the preform web-flange half model is B2, and the width of the preform flange model is B 22 , then in the same cross section perpendicular to the length direction, any position meets B2=B 21 +B 22 ; Assume that the distance from the symmetry plane D of the Ω-shaped half model to the outer edge of the forging fillet is B R , any position meets B 21 ≥B R ,by Figure 8Take (a)(d) as an example, B 21 =372mm, B R =251mm, B 21 >B R ;

[0076] For the V-shaped part, let the angle between the inner wall of the forging web and the symmetry plane D be θ1, and let the angle between the cutout and the bottom surface of the preform web half model be θ2. Then, under the same cross section, any position meets the condition that θ2 = (0.7-1.3)θ1. Figure 8 (b) (e) For example, θ2=23°, θ1=25°, θ2=0.92θ1;

[0077] 5. In the 3D modeling software, a preform fillet is added between the preform flange model and the preform web half model to obtain a preform half model;

[0078] Assume that the fillet radius of the preform is R 23 , R 23 =200mm, R 23 >(R 13 ) max ;

[0079] Assume that the cross-sectional area of ​​the preform half model perpendicular to the length direction is S3, and the cross-sectional area of ​​the preform fillet perpendicular to the length direction is S 23 , then in the same cross section perpendicular to the length direction, any position satisfies S3=S 21 +S 22 +S 23 ; Assume that the width of the preform half model is B3, then in the same cross section perpendicular to the length direction, any position meets B2=B3=B 21 +B 22 ; Assume that the cross-sectional area of ​​the half model part II of the Ω-shaped part perpendicular to the length direction is S Ⅱ , then in the same cross section perpendicular to the length direction, any position meets S 22 +S 23 =(1.0~1.3)S Ⅱ ,by Figure 8 (a)(d) as an example, S 22 +S 23 =13994mm 2 , S Ⅱ =13486mm 2 , S 22 +S 23 =1.04S Ⅱ ;

[0080] Assume the thickness of the prefabricated web half model is T 21 , let the total arc length of the inner wall of the Ω-shaped half model be Assume that the total arc length of the outer wall of the Ω-shaped half model is Assume that the fillet radius of the Ω-shaped forging is R 13 , in the same cross section perpendicular to the length direction, when R 13 >T 21 When , any position meets the by Figure 8 (a)(d) as an example, R 13 =70m, T 21 =63mm, B3=448mm; In the same section perpendicular to the length direction, when R 13 <T 21 When any position meets by Figure 8 (c)(f) as an example, R 13 =30mm, T 21 =87mm, B3=412mm,

[0081] 6. In the 3D modeling software, the preform half model is mirrored with plane E as the symmetry plane to obtain the preform model;

[0082] 7. A method for designing a preform of a large-size variable-section Ω-shaped part is completed by preparing the preform according to the preform model.

[0083] In step 1, the length of the Ω-shaped piece is assumed to be L1, L1 = 1580 mm;

[0084] In step 1, the maximum height of the Ω-shaped piece along the height direction of the U-shaped opening is (H1) max , (H1) max =423mm, B 1: (H1) max =1.28:1.

[0085] In step 1, the minimum thickness of the forging web is assumed to be (T 11 ) min , (T 11 ) min =44mm, B 1: (T 11 ) min =12.27:1.

[0086] In step 4, the angle between the side surface F of the forged flange along the length direction of the Ω-shaped piece and the symmetry plane D of the Ω-shaped piece is θ FD , 0°≤θ FD ≤60°, let the dihedral angle between plane G and plane E be θ GE ,θ GE =(90°-θFD );Let the length of the intersection of the cross section perpendicular to the length direction of the Ω-shaped half model and the plane F in the middle of the Ω-shaped half model part II be B F , let the length of the intersection line between the cross section at the corresponding position of the preform flange model and the plane G of the preform flange model be B G , any position meets B G =(1~2.5)B F ,by Figure 7 Take section C in (a) and (b) as an example, B F =72mm, B G =140mm=1.94B F .

[0087] The preform described in step seven is a variable-section structure that is symmetrical on both sides. The preform consists of a preform web and a preform flange. The cross-section of the preform web is rectangular. One-way raised preform flanges are arranged on both sides of the preform web along the thickness direction of the preform web, and preform fillets are arranged at the connection between the preform web and the preform flange.

[0088] The preform forging forming method of the above-mentioned design is carried out according to the following steps:

[0089] The preform is placed on the lower die with its opening downward, and then the upper die is pressed to form the preform, thereby completing the bending forging forming method of the large-sized variable-section Ω-shaped part using the preform, and obtaining the large-sized variable-section Ω-shaped part.

[0090] Fig. 9 For example, the Ω-shaped half model is Figure 1 (c) Finite element simulation of the bending forging forming process at section C, (a) is the initial state, (b) is the intermediate step, (c) is the inner surface of the flange of the formed part contacts the inner surface of the upper mold cavity, (d) is the upper surface of the flange of the formed part contacts the upper surface of the upper mold cavity, and (e) is the final result; Fig.10 This is a finite element simulation formed part of a large-sized variable-section Ω-shaped part prepared in Example 1. (a) is a direct view of the convex surface, and (b) is a direct view of the concave surface. It can be seen that the forging is well formed without defects such as insufficiency or folding.

[0091] Comparative Example 1, combined Figures 11 to 12 :

[0092] The difference between this comparative example and the first embodiment is that in step 5, at the same cross section perpendicular to the length direction, when R 13 <T 21 When , any position meets the by Fig.11 Taking the cross section C as an example, R 13 =30mm, T 21 =72mm, B3 = 471 mm. The rest is the same as in the first embodiment.

[0093] Fig.12 For the comparative example, a half-model of an Ω-shaped part is Figure 1 (c) Finite element simulation of the bending forging process at section C, (a) is the initial state, (b) is the intermediate step, (c) is the upper surface of the flange of the formed part contacts the upper surface of the upper mold cavity, and (d) is the final result; Fig.12 (c) It can be seen that due to the excessive width of the preform, the flange of the preform first contacts the upper surface of the upper mold cavity before contacting the inner surface of the upper mold cavity during bending, resulting in the flange not bending properly, thus causing the flange cavity to be incompletely filled. Fig.12 (d) as shown.

Claims

1. A preform design method for large-size variable-section Ω-shaped parts, characterized in that It is carried out in the following steps:

1. In the 3D modeling software, a half model of the Ω-shaped part is constructed along the symmetry plane D in the length direction of the Ω-shaped part; The Ω-shaped piece is a large-sized, bilaterally symmetrical variable-section Ω-shaped structure, and the Ω-shaped piece is composed of a forged web and a forged flange. Forged flanges are arranged on both sides of the opening of the forged web, and forged fillets are arranged at the connection between the forged web and the forged flange. The maximum width of the Ω-shaped piece along the opening width direction is B1, and B1 of different cross sections in the vertical length direction of the Ω-shaped piece is the same, and the side surface F of the forged flange along the length direction of the Ω-shaped piece is a plane, and the upper edge of the side surface F is located on the same straight line K; The forging web is one of U-shaped and V-shaped or a combination of the two. When it is U-shaped, the straight wall portion of the forging web is parallel to the symmetry plane D, and when it is V-shaped, there is an angle between the straight wall portion of the forging web and the symmetry plane D.

2. In the 3D modeling software, set a plane E on the Ω-shaped half model. Plane E is perpendicular to the symmetry plane D. Plane E divides the Ω-shaped half model into part I, which is mainly composed of the forging web, and part II, which is mainly composed of the forging flange. Set the vertical distance between plane E and straight line K to be B. E , assuming that the maximum radius of the forging corner of the Ω-shaped part is (R 13 ) max , B E :(R 13 ) max =(0.5~1):1, then draw the longitudinal section profile of the web of the preform on plane E; the longitudinal section profile of the web of the preform covers the section profile of the Ω-shaped part half model on plane E; Assume that the cross-sectional thickness of the Ω-shaped half model on plane E is T 1E , assuming that the thickness of the longitudinal section profile of the preform web is T 2E , then at the same position, T 1E :T 2E =(0.6~1):1; Let the distance between the thickness center line of the cross-section profile of the Ω-shaped half model on plane E and the thickness center line of the longitudinal cross-section profile of the web of the preform be H 12 , then at the same position, H 12 :T 1E =(0~0.2):1; 3. In the 3D modeling software, the longitudinal section profile of the web of the preform is subjected to unidirectional stretching bosses in a direction perpendicular to the length direction to obtain a half model of the web of the preform; Assume that the width of the prefabricated web half model is B 21 , assuming that the cross-sectional area of ​​the prefabricated web half model perpendicular to the length direction is S 21 , let the cross-sectional area of ​​the Ω-shaped half model part I perpendicular to the length direction be S Ⅰ , then in the same section perpendicular to the length direction, S 21 =(1.1~1.4)S Ⅰ ; Fourth, in the three-dimensional modeling software, a plane G is set above the edge along the length direction of the preform web half model, and the preform flange profile is drawn on the plane G. The preform flange profile is stretched along the direction perpendicular to the length direction and parallel to the plane E until the preform flange model and the bottom surface of the preform web half model are coplanar, and then according to the angle between the straight wall part of the forging web of the V-shaped part and the symmetry plane D, the co-bottom surface of the preform flange model and the preform web half model is cut off at the corresponding position to form an incision, so as to obtain the preform web-flange half model; Assume that the cross-sectional area of ​​the preform flange model perpendicular to the length direction is S 22 ; Assume that the distance from the symmetry plane D of the Ω-shaped half model to the outer edge of the forging fillet is B R , B 21 ≥B R ; 5. In the 3D modeling software, a preform fillet is added between the preform flange model and the preform web half model to obtain a preform half model; Assume that the fillet radius of the preform is R 23 , R 23 >(R 13 ) max ; Assume that the cross-sectional area of ​​the preform fillet perpendicular to the length direction is S 23 , let the width of the preform half model be B3, let the cross-sectional area of ​​the Ω-shaped half model part II perpendicular to the length direction be S Ⅱ , then in the same section perpendicular to the length direction, S 22 +S 23 =(1.0~1.3)S Ⅱ ; Assume the thickness of the prefabricated web half model is T 21 , let the total arc length of the inner wall of the Ω-shaped half model be , let the total arc length of the outer wall of the Ω-shaped half model be , assuming that the fillet radius of the Ω-shaped forging is R 13 , then in the same cross section perpendicular to the length direction, when R 13 >T 21 When B3<0.5( + ), when R 13 <T 21 When B3< ; 6. In the three-dimensional modeling software, the preform half model is mirrored with plane E as the symmetry plane to obtain a preform model, and the preform is prepared according to the preform model, thus completing the preform design method for large-size variable-section Ω-shaped parts.

2. The preform design method for large-size variable-section Ω-shaped parts according to claim 1 is characterized in that In step 1, the length of the Ω-shaped piece is assumed to be L1, and L1 ≥ 800 mm.

3. The preform design method for large-size variable-section Ω-shaped parts according to claim 1 is characterized in that In step 1, the maximum height of the Ω-shaped piece along the height direction of the U-shaped opening is (H1) max , B 1: (H1) max =(0.5~4):

1.

4. The preform design method for large-size variable-section Ω-shaped parts according to claim 1 is characterized in that In step 1, the minimum thickness of the forging web is (T 11 ) min , B 1: (T 11 ) min =(5~25):

1.

5. The method for designing a preform of a large-size variable-section Ω-shaped part according to claim 1, characterized in that In step 4, the cross-sectional area of ​​the prefabricated web-flange half model perpendicular to the length direction is S2. Then, under the same cross section perpendicular to the length direction, S2=S 21 +S 22 ; Assume that the width of the preform web-flange half model is B2, and the width of the preform flange model is B 22 , then in the same section perpendicular to the length direction, B2=B 21 +B 22 .

6. The method for designing a preform of a large-size variable-section Ω-shaped part according to claim 5, characterized in that In step 5, the cross-sectional area of ​​the preform half model perpendicular to the length direction is S3, and the cross-sectional area of ​​the preform fillet perpendicular to the length direction is S 23 , then in the same section perpendicular to the length direction, S3=S 21 +S 22 +S 23 ; Assume that the width of the preform half model is B3, then in the same section perpendicular to the length direction, B2=B3=B 21 +B 22 .

7. The preform design method for large-size variable-section Ω-shaped parts according to claim 1 is characterized in that For the V-shaped part in step 4, let the angle between the inner walls on both sides of the forging web and the symmetry plane D be θ1, and let the angle between the cut and the bottom surface of the preform web half model be θ2. Then, under the same section, θ2=(0.7~1.3)θ1.

8. The method for designing a preform of a large-size variable-section Ω-shaped part according to claim 1, characterized in that In step 4, the angle between the side surface F of the forged flange along the length direction of the Ω-shaped piece and the symmetry plane D of the Ω-shaped piece is θ FD , 0°≤θ FD ≤60°, let the dihedral angle between plane G and plane E be θ GE ,θ GE =(90°-θ FD );Let the length of the intersection of the cross section perpendicular to the length direction of the Ω-shaped half model and the plane F in the middle of the Ω-shaped half model part II be B F , let the length of the intersection line between the cross section at the corresponding position of the preform flange model and the plane G of the preform flange model be B G , B G =(1~2.5)B F .

9. The method for designing a preform of a large-size variable-section Ω-shaped part according to claim 1, characterized in that The preform described in step six is ​​a variable-section structure that is symmetrical on both sides. The preform consists of a preform web and a preform flange. The cross-section of the preform web is rectangular. One-way raised preform flanges are arranged on both sides of the preform web along the thickness direction of the preform web, and preform fillets are arranged at the connection between the preform web and the preform flange.

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