Method and die for one-time die forging bending forming of ultra-wide and ultra-thick arc-shaped forge piece

Abstract

The invention provides a method and a die for one-time die forging bending forming of an ultra-wide and ultra-thick arc-shaped forge piece, and belongs to the technical field of metal material forming. In order to solve the problems that the structure performance, the forging period and the cost cannot be considered at the same time during forging of the ultra-wide and ultra-thick arc-shaped forge piece, the invention provides a die which comprises an upper die and a lower die. The upper die comprises an arc-shaped plate, a supporting block arranged on the inner arc surface of the arc-shaped plate and a plurality of reinforcing ribs arranged at the joint of the arc-shaped plate and the supporting block, the lower die comprises two supporting plates which are oppositely arranged and a pulling plate connected with the side edges of the two supporting plates, and the supporting plates are used for bearing a blank in the length direction; according to the die forging bending forming process, the die forging bending forming process is achieved through cooperation of the upper die with the small width and the open type lower die, and the forging cost is reduced by reducing the die cost on the basis that the structure performance and the short forging period are guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of metal material forming, and in particular to a method for one-time die forging and bending forming of ultra-wide and ultra-thick arc-shaped forgings and a die thereof. Background Art

[0002] In recent years, my country has made brilliant achievements in the field of high-end manufacturing. Many large-scale infrastructure, large scientific facilities, military industry, nuclear power and other fields have developed in the direction of large-scale, integrated and high-performance, requiring a large number of large forgings with complex shapes and excellent performance as technical support.

[0003] 1. Traditional small arc parts are usually narrow in width, thin in thickness, and have low requirements for performance uniformity. Generally, small arc anvils are used to bend them segment by segment. As shown in Figure 1(a)-(b), the jaws 1 of the manipulator are used to clamp one end of the slab (usually a conventional rectangular slab), and the other end is placed on the lower arc anvil 3. The upper arc anvil 2 (the anvil surface of the arc anvil is arc-shaped, and the anvil surface radius is the same as the inner radius of the arc forging) is used to bend them segment by segment.

[0004] This method can be used to bend arc forgings with small thickness and radius. When using this method to bend arc forgings with larger sizes, firstly, the operation is difficult and the clamping position needs to be changed constantly, which may cause the forging to fall due to unstable clamping. Secondly, the bending of each section needs to be compared and trimmed with the sample constantly, which takes a long time. As the temperature of the forging gradually decreases during the forging process, the organization and performance of each area of ​​the forging will also be different. In addition, the diameter of large arc forgings is usually more than 8 meters. It is very difficult to match the radial size of each section with the delivery drawing when bending each section. It usually requires multiple rounds of trimming, which is difficult to meet the performance requirements of current high-end equipment.

[0005] 2. In traditional die forging bending, the width of the upper and lower anvil surfaces is usually ≥ the width of the arc forging, and the upper and lower anvils usually use the same inner and outer diameters as the arc forging, and the forging is completely formed by forced extrusion of the upper and lower dies. During the bending process of large arc forgings, especially when the arc forging is thicker (thickness ≥ 500mm) and wider (width ≥ 2000mm) (width-to-thickness ratio is less than or equal to 5), during the bending process, the material of the inner circle of the arc forging is extruded and accumulated, causing the material to flow in the width direction and widen the width. The outer circle of the arc forging is thinned during the bending process, resulting in the reduction of the width direction. Therefore, the cross-section of the slab will be distorted from the original rectangle to an "arch bridge shape", such as Figure 2 As shown in the cross-section of the forging after bending (yellow is the forging cross-section, and gray is the delivery drawing cross-section), both sides of the width direction will be twisted in the non-centripetal direction, and the smaller the width-to-thickness ratio, the more severe the distortion.

[0006] Therefore, the traditional upper and lower die forced extrusion method has the following disadvantages:

[0007] 1. The bending process needs to go through two stages: bending and squeezing and closing. It requires very high pressure, and the press pressure becomes the main limiting condition:

[0008] 2. The die surface needs to fit the forging completely to meet the size requirements of the forging. The larger the forging, the larger the die will need. Usually, an integral casting is required. And with the huge pressure of the press, the die needs to be made of higher strength material, and the die cost also increases accordingly. Summary of the invention

[0009] The purpose of the present application is to solve the problem in the prior art that the forging of ultra-wide and ultra-thick arc forgings cannot take into account both the structural performance, forging cycle and cost. Therefore, the present application provides a one-time die forging bending forming method and a die thereof for ultra-wide and ultra-thick arc forgings. The die realizes the die forging bending forming process by cooperating with an upper die with a smaller width and an open lower die. On the basis of ensuring the structural performance and a shorter forging cycle, the die cost is reduced, thereby reducing the forging cost.

[0010] The embodiment of the present application provides a die for one-time die forging and bending of ultra-wide and ultra-thick arc-shaped forgings, comprising an upper die and a lower die;

[0011] The upper mold includes an arc-shaped plate, a support block arranged on the inner arc surface of the arc-shaped plate, and a plurality of reinforcing ribs arranged at the connection between the arc-shaped plate and the support block;

[0012] The outer arc surface of the arc plate is used to form the inner arc surface of the forging, and R 1 =(1.007-1.009)×R 0 , 0.6B 0 ≤B 1 <B 0 , A 1 =(0.05-0.15)A 0 And A 1 ≥60mm;

[0013] The support block is located in the width center area of ​​the arc plate and extends along the arc surface of the arc plate. 2 =(0.45-0.55)B 1 ;

[0014] The plurality of reinforcing ribs are evenly distributed at the connection between the arc plate and the support block, and are all oriented toward the center of the arc plate. The reinforcing ribs include a first side edge and a second side edge adjacent to each other. The first side edge is connected to the support block, and the second side edge is connected to the arc plate. 3 ≥3A 1 , B 3 =(0.2-0.3)B1 , A 3 =(0.45-0.55)A 1 , the interval between two adjacent reinforcing ribs is 10-12°;

[0015] The lower die comprises two supporting plates arranged opposite to each other, and a pulling plate connecting the sides of the two supporting plates, wherein the supporting plates are used to carry the blank along the length direction;

[0016] Among them, the length, width and thickness of the rectangular blank are L 0 , B 0 , A 0 The radius, width and thickness of the arc plate are R 1 , B 1 , A 1 The length, width and thickness of the support block are L 2 , B 2 , A 2 The length, width and thickness of the reinforcement rib are L 3 , B 3 , A 3 .

[0017] By adopting the above technical scheme, the die forging bending forming is realized by cooperating with the upper die and the lower die, which can ensure the microstructure and performance of the forging and a shorter forging cycle; and, by using an upper die whose width is much smaller than the width of the billet and an open lower die, the die cost is reduced, thereby reducing the forging cost; and while ensuring the overall strength of the upper die through the support block and the reinforcing ribs, the width of the support block is only about half of the width of the arc plate, and the remaining width is supported by the reinforcing ribs, which further reduces the size and weight of the die and reduces the forging cost.

[0018] In some embodiments, the yield strength of the arc plate and the support block is not less than 270 MPa; the yield strength of the reinforcing rib is not less than 225 MPa.

[0019] By adopting the above technical solution, the yield strength of the arc plate, the support block and the reinforcing ribs is selected to further ensure the strength of the upper die and improve the forging stability and reliability.

[0020] In some embodiments, the pull plate and the support plate are connected by blind holes and latches, and 1 =φ 0 +1mm, L 盲孔 ≥ 2 / 3 L 插销 , L 插销 ≥550mm, of which,

[0021] The diameter of the pin is φ 0 , length L 插销 , the blind hole diameter is φ 1 , the depth is L盲孔 .

[0022] By adopting the above technical solution, the difficulty of lower die forging is reduced, the lower die forging cycle is shortened, thereby reducing the lower die forging cost, and further reducing the arc part forging cost.

[0023] In some embodiments, the lower mold further includes a positioning block and a backing plate;

[0024] The positioning block is arranged on the working surface of the support plate;

[0025] The pad is arranged at the middle position of the two support plates and is used to fit the corresponding outer arc surface of the forging when the blank is bent into the forging.

[0026] By adopting the above technical solution, the bottom of the arc plate of the upper die and the top of the support plate of the lower die can be contacted to zero position through the positioning block, thereby ensuring that the blank is located in the center of the die, thereby ensuring the microstructure and performance of the forged forging and ensuring forging safety.

[0027] The embodiment of the present application also provides a method for one-time die forging and bending of an ultra-wide and ultra-thick arc-shaped forging, using any of the above-mentioned dies, and the method comprises:

[0028] S1 Prefabricated trapezoidal billet: Forged trapezoidal billet, and B 上底 =0.96×B 0 , B 下底 =1.05×B 0 , where the width of the rectangular blank section is B 0 The width of the upper bottom of the front cross section of the trapezoidal blank is B 上底 , the bottom width is B 下底 ;

[0029] S2 mold assembly and positioning: the mold is manufactured according to the size of the rectangular blank, and the upper mold of the mold is assembled with the 10,000-ton press, and the relative positions of the upper mold and the lower mold of the mold are adjusted so that the upper mold and the lower mold are centered and zero position is confirmed;

[0030] S3 forging forming: placing the trapezoidal blank on the lower die, and using the upper die to press the trapezoidal blank one by one.

[0031] By adopting the above technical scheme, the special die of the present application is used to forge ultra-wide and ultra-thick arc forgings, which takes into account the organizational performance, forging cycle and cost; and, on the basis of the conventional rectangular billet, it is improved to a trapezoidal billet, which can reduce the distortion during the forging process, thereby improving the uniformity of the allowance distribution, ensuring sufficient allowance everywhere, and reducing the risk of forging forming size; and, due to precise allowance control, the forged trapezoidal billet does not require the rough processing step before bending in the conventional process, and can be bent directly, thereby further improving the uniformity of the organizational performance of the formed forging, and further shortening the forging cycle and reducing the forging cost, and the maximum degree of contour forging meets the product requirements.

[0032] In some embodiments, the trapezoidal billet is kept at 1050-1100° C. for 8-12 hours.

[0033] In some embodiments, step S3 of pressing step by step refers to pressing down at intervals for multiple times, and each pressing amount is 100 mm, and the number of pressing times is 12 times.

[0034] Other features and corresponding beneficial effects of the present application are described in the latter part of the specification, and it should be understood that at least some of the beneficial effects become obvious from the records in the specification of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1( a ) is a schematic diagram of a small arc forging forming preparation stage in the prior art;

[0036] FIG1( b ) is a schematic diagram of the forming forging stage of a small arc forging in the prior art;

[0037] Figure 2 A schematic diagram of the cross-sectional distortion of an arc-shaped forging after bending, which is forged by a conventional die forging bending forming method;

[0038] Figure 3 A schematic diagram of the dimensions of the upper die of an embodiment of the present application and a conventional rectangular blank;

[0039] Figure 4 This is a schematic structural diagram of the lower mold of an embodiment of the present application;

[0040] FIG5( a ) is a schematic diagram of the structure of a conventional through-hole plug;

[0041] FIG5( b ) is a schematic structural diagram of a blind hole type latch of a lower mold according to an embodiment of the present application;

[0042] Figure 6 This is a schematic diagram of the dimensions of a trapezoidal blank according to an embodiment of the present application;

[0043] Figure 7 Schematic diagram of the forging process before and after bending using the traditional die forging bending forming method and the traditional billet matching forging;

[0044] Figure 8 This is a schematic diagram of the die and trapezoidal blank in the embodiment of the present application for forging, before and after bending;

[0045] Fig. 9 This is a schematic diagram of measuring the radius of an arc forging according to an embodiment of the present application.

[0046] Description of reference numerals:

[0047] 1. Operating machine jaws; 2. Upper arc anvil; 3. Lower arc anvil;

[0048] 10. Upper die; 11. Arc plate; 12. Support block; 13. Reinforcement rib;

[0049] 20. Lower die; 21. Support plate; 22. Pull plate; 23. Latch; 24. Pad; 25. Positioning block;

[0050] 30. Trapezoidal blank; 31. Rectangular blank. DETAILED DESCRIPTION

[0051] The following specific embodiments illustrate the implementation of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with the preferred embodiment, this does not mean that the features of this application are limited to the implementation. On the contrary, the purpose of introducing the application in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide a deep understanding of the present application, the following description will include many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0052] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0053] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", and "third" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description created by the present application, unless otherwise specified, "multiple" means two or more. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0054] Embodiment 1:

[0055] See also Figure 3-4 , Figure 3 It is a schematic diagram of the dimensions of the upper mold 10 of the embodiment of the present application and the conventional rectangular blank 40; Figure 4 Schematic diagram of the structure of the lower mold 20 according to an embodiment of the present application.

[0056] The embodiment of the present application provides a die forging and bending forming of ultra-wide and ultra-thick arc-shaped forgings in one step, including an upper die 10 and a lower die 20, so that the process can adopt die forging and bending forming, which solves the problems of low degree of profiling, high risk of structural performance and great difficulty in operation caused by traditional segmented bending forming (i.e., traditional forging method of small arc-shaped parts), thereby ensuring the structural performance of the forgings and achieving a shorter forging cycle.

[0057] It should be noted that in order to ensure the size of the bending forming, the width of the traditional curved upper die 10 in the die forging bending forming process generally has to completely cover the width of the blank, that is, the die width ≥ the blank width. Therefore, the wider the blank, the wider the die, which will greatly increase the die cost.

[0058] See also Figure 3In one embodiment, in order to reduce the mold cost while ensuring the mold strength, the upper mold 10 includes an arc plate 11, a support block 12 arranged on the inner arc surface of the arc plate 11, and a plurality of reinforcing ribs 13 arranged at the connection between the arc plate 11 and the support block 12. The outer arc surface of the arc plate 11 is used to form the inner arc surface of the forging, and the arc plate 11 with limited strength is supported by the support block 12 and the reinforcing ribs 13, so that the overall strength of the upper mold 10 meets the requirements, and the cooperation of the arc plate 11, the support block 12 and the reinforcing ribs 13 can reduce the weight of the upper mold 10 by more than 60% relative to the conventional upper mold 10.

[0059] Here, the parameters involved in the following description are as follows: the length, width and thickness of the rectangular blank 40 are L and L respectively. 0 , B 0 , A 0 The outer arc radius, width and thickness of the arc plate 11 are R 1 , B 1 , A 1 The length, width and thickness of the support block 12 are L 2 , B 2 , A 2 The length, width and thickness of the reinforcing rib 13 are L 3 , B 3 , A 3 .

[0060] The size of the rectangular blank 40 can be determined by a person skilled in the art according to a conventional blank size calculation method of a conventional forging and bending forming process.

[0061] In one embodiment, 0.6B 0 ≤B 1 <B 0 , A 1 =(0.05-0.15)A 0 And A 1 ≥60mm. Preferably, A 1 =0.1A 0 This method reduces the die cost by using the upper die 10 whose width is much smaller than the width of the blank, thereby reducing the forging cost.

[0062] Preferably, the yield strength of the arc plate 11 is not less than 270 MPa, for example, ZG270-500 or a material with higher strength is used to further ensure the strength of the arc plate 11 itself, thereby ensuring the strength of the upper die 10 and improving the forging stability and reliability.

[0063] It should be noted that, for generally thinner and narrower small arc forgings, the radius of the upper die 10 contoured arc plate is basically the same as the radius of the arc forgings. However, it is not applicable to ultra-wide and ultra-thick arc forgings, especially arc forgings with a thickness of ≥500mm, a width of ≥2000mm, a width-to-thickness ratio of ≤5, and a bending angle of 90°. After bending, the cross-section of the blank of such forgings is "arch bridge-shaped", resulting in tight margins, and it is difficult to meet the size requirements of the arc forgings after bending.

[0064] Therefore, in one embodiment, R 1 =(1.007-1.009)×R 0 , preferably, R 1 =1.008×R 0 By making the radius of the upper die 10 slightly larger than the radius of the forging, the "arch bridge-shaped" area can be further squeezed during the forging process to even out the excess, so that the size of the bent forging after bending can meet the requirements of the delivery drawing.

[0065] In one embodiment, the support block 12 is located in the width center area of ​​the arc plate 11 and extends along the arc surface of the arc plate 11, that is, the support block 12 is symmetrically arranged about the center line of the width side of the arc plate 11 and covers the arc length of the arc plate 11, thereby ensuring that the support block 12 uniformly supports the arc plate 11.

[0066] Preferably, B 2 =(0.45-0.55)B 1 , further, B 2 =0.5B 1 , that is, the width of the support block 12 is only about half of the width of the arc-shaped plate 11, which further reduces the size and weight of the mold and reduces the forging cost.

[0067] Preferably, the yield strength of the support block 12 is not less than 270 MPa, for example, ZG270-500 or a material with higher strength is used to further ensure the strength of the support block 12 itself, thereby ensuring the strength of the upper die 10 and improving the forging stability and reliability.

[0068] In one embodiment, a plurality of reinforcing ribs 13 are evenly distributed at the connection between the arc plate 11 and the support block 12, thereby supporting the area of ​​the arc plate 11 not covered by the support block 12, ensuring the strength of the upper mold 10, and the reinforcing ribs 13 are small in size and weight, which can further reduce the forging cost.

[0069] Since the connection between the ends of the arc-shaped plate 11 and the support block 12 is relatively short, a reinforcing rib 13 is usually provided at the connection between the arcs of the two.

[0070] Preferably, the plurality of reinforcing ribs 13 are all oriented toward the center of the arc plate 11, and generally a triangular reinforcing rib 13 is used, with the vertex pointing toward the center of the arc plate 11, so as to improve the overall strength. Further, the reinforcing rib 13 includes a first side edge and a second side edge adjacent to each other, the first side edge is connected to the support block 12, and the second side edge is connected to the arc plate 11, L 3 ≥3A 1 , B 3 =(0.2-0.3)B 1 , A 3 =(0.45-0.55)A 1 , the interval between two adjacent reinforcing ribs 13 is 10-12°, for example, B 3 =0.25B 1 , A 3 =0.5A 1 , 22 reinforcing ribs 13 are used, namely 11 on each side, and the interval between two adjacent reinforcing ribs 13 is 11°.

[0071] Preferably, the yield strength of the reinforcing rib 13 is not less than 225 MPa, for example, Q235 or other materials with higher strength are used to further ensure the strength of the reinforcing rib 13 itself, thereby ensuring the strength of the upper die 10 and improving the forging stability and reliability.

[0072] See also Figure 4 In one embodiment, the lower die 20 includes two support plates 21 disposed opposite to each other, and a pulling plate 22 connecting the sides of the two support plates 21, and the support plates 21 are used to support the blank along the length direction.

[0073] Preferably, the support surface of the support plate 21 has a guide portion, so that the blank is bent along the guide portion toward the inside of the lower die 20 under the extrusion of the upper die 10 .

[0074] It should be noted that the conventional die forging bending forming process uses a lower die that matches the shape and size of the arc forging. The lower die is large in size and weight, resulting in a high manufacturing cost for the lower die.

[0075] This method reduces the mass of the lower mold by opening the lower mold, thereby reducing the manufacturing cost.

[0076] In addition, the traditional die forging bending forming process needs to go through two stages: bending and extrusion closing, and the pressure required for the final extrusion process increases sharply.

[0077] The shape of the upper die of the present application is similar to that of the forging, and the lower die adopts an open die which mainly plays a bearing role. The forming can be completed through the bending process, which greatly reduces the huge pressure required for the die closing and extrusion, thereby reducing the demand for the pressure performance of the press.

[0078] In a specific embodiment, each side of the two support plates 21 is connected by six pull plates 22 and twelve latches 23 .

[0079] Please refer to Figures 5(a)-(b), Figure 5(a) is a schematic diagram of the structure of a traditional through-hole type pin 23; Figure 5(b) is a schematic diagram of the structure of a blind hole type pin 23 of the lower mold 20 of an embodiment of the present application.

[0080] It should be noted that most conventional pins 23 are designed as through holes, that is, the pins 23 penetrate the entire support plate 21 of the lower die 20. However, when the arc-shaped forging is an ultra-wide and ultra-thick forging, the size and strength requirements of the lower die 20 are increased, that is, the support plate 21 and the pull plate 22 are larger in size, have higher strength, and require higher reliability in connection between the two, which makes it difficult to process the through hole and takes a long time. In addition, the pins 23 will bend and deform under stress, which sometimes requires destructive removal, further increasing the forging cost.

[0081] Therefore, in some embodiments, the pull plate 22 and the support plate 21 are connected by blind holes and latches 23, and φ 1 =φ 0 +1mm, pin 23 diameter φ 0 According to the stress conditions and the selected materials, the pin 23 and the blind hole are matched with a small clearance to ensure the stability and reliability of the connection between the two. 盲孔 ≥ 2 / 3 L 插销 , that is, the pin 23 ensures that at least 2 / 3 of its length extends into the blind hole, and L 插销 ≥550mm, thereby ensuring the connection strength between the two. Among them, the diameter of the pin 23 is φ 0 , length L 插销 , the blind hole diameter is φ 1 , the depth is L 盲孔 .

[0082] This method reduces the difficulty of forging the lower die 20 and shortens the forging cycle of the lower die 20, thereby reducing the forging cost of the lower die 20 and further reducing the forging cost of the arc-shaped part.

[0083] In some embodiments, the lower mold 20 further includes a positioning block 25 and a backing plate.

[0084] The positioning block 25 is disposed on the working surface of the supporting plate 21 .

[0085] The backing plate is disposed in the middle of the two support plates 21 and is used to fit the corresponding outer arc surface of the forging when the blank is bent into the forging.

[0086] This method can achieve zero contact between the bottom of the arc plate 11 of the upper die 10 and the top of the support plate 21 of the lower die 20 through the positioning block 25, thereby ensuring that the blank is located in the center of the die, thereby ensuring the structural performance of the forged forging and ensuring forging safety.

[0087] Embodiment 2:

[0088] On the basis of Example 1, the embodiment of the present application also provides a method for one-time die forging and bending of ultra-wide and ultra-thick arc-shaped forgings, using the mold of Example 1.

[0089] See also Figure 3-6 , Figure 3 It is a schematic diagram of the dimensions of the upper mold 10 of the embodiment of the present application and the conventional rectangular blank 40; Figure 4 5( a ) is a schematic diagram of the structure of a conventional through-hole type latch 23 ; and FIG. 5( b ) is a schematic diagram of the structure of a blind hole type latch 23 of the lower mold 20 of the embodiment of the present application. Figure 6 It is a schematic diagram of the dimensions of the trapezoidal blank 30 according to the embodiment of the present application.

[0090] The method includes:

[0091] S1 Prefabricated trapezoidal billet 30: Forged trapezoidal billet 30, and B 上底 =0.96×B 0 , B 下底 =1.05×B 0 , where the cross-sectional width of the rectangular blank 40 is B 0 , the width of the upper bottom of the front cross section of the trapezoidal blank 30 is B 上底 , the bottom width is B 下 end.

[0092] S2 mold assembly and positioning: the mold is manufactured according to the size of the rectangular blank 40, and the upper mold 10 of the mold is assembled with the 10,000-ton press, and the relative positions of the upper mold 10 and the lower mold 20 of the mold are adjusted so that the upper mold 10 and the lower mold 20 are centered and the zero position is confirmed;

[0093] S3 forging forming: placing the trapezoidal blank 30 on the lower die 20 , and using the upper die 10 to press the trapezoidal blank 30 one by one.

[0094] The method takes into account the organizational performance, forging cycle and cost by adopting the special die of the present application to forge ultra-wide and ultra-thick arc forgings.

[0095] See also Figure 7-8 , Figure 7 Schematic diagram of the forging process before and after bending using the traditional die forging bending forming method and the traditional billet matching forging; Figure 8This is a schematic diagram of the upper die 10 and the trapezoidal blank 30 cooperated in forging according to an embodiment of the present application, before and after bending.

[0096] It should be noted that the material of the inner circle of the arc forging is extruded and accumulated during the bending process, causing the material to flow along the width direction and widen the width. The outer circle of the arc forging is thinned during the bending process, resulting in the shrinkage of the width direction. Figure 2 As shown in the figure, the cross section of the slab is twisted from the original rectangle to an "arch bridge shape". The gray part in the figure is the delivery size, and the yellow part is the cross-sectional size after bending. It can be seen from the figure that the allowance distribution is extremely uneven, resulting in a great risk of forming size for forgings.

[0097] The present application found that when the bending angle of the blank reaches 90°, the elongation rate of the inner arc width is about 4%, and the thinning rate of the outer arc width is about 5%.

[0098] To this end, based on the conventional rectangular billet 40, the present application improves the trapezoidal billet 30, which can reduce the material at the extrusion part (i.e., the upper bottom), compensate for the thinning part (i.e., the lower bottom), and reduce the distortion during the forging process, thereby further improving the uniformity of the margin distribution, ensuring sufficient margins at all locations, and reducing the risk of forging size. In addition, due to the precise margin control, the forged trapezoidal billet 30 can be directly bent without the rough processing process before bending in the conventional process, thereby further improving the uniformity of the structure and performance of the formed forging, and further shortening the forging cycle and reducing the forging cost, and the maximum degree of profiling forging meets the product requirements.

[0099] It should be noted that before conventional blanks are bent, they need to be processed to remove all black skin and arc heads on the surface of the blanks, and they must comply with the rough processing diagram before bending. This is because the shape control accuracy of the conventional bending process is poor. If the surface is bent with black skin, the dimensional risk after bending is greater, and if the blanks are not processed, there will be arc heads, making it difficult to position the blanks before bending.

[0100] In some embodiments, the trapezoidal blank 30 is kept at 1050-1100° C. for 8-12 hours to improve the forging effect.

[0101] In some embodiments, step S3 of pressing step by step refers to pressing down at intervals for multiple times, and each pressing amount is 100 mm, and the number of pressing times is 12 times, so as to further ensure the forging effect.

[0102] In a specific embodiment, the method is:

[0103] S1 Prefabricated trapezoidal billet 30: After multiple overall upsetting and WHF method elongation, the steel ingot obtains a good forging compaction effect. Prefabricated "trapezoidal" cross-section billet, "trapezoidal" cross-section upper bottom B 上底 =2170mm, B 下底 =2380mm, thickness A梯 =860mm, slab length L 梯 =6050mm, billet size Figure 6 As shown, the prefabricated slab does not require rough machining after forging.

[0104] S2 mold assembly and positioning: the arc plate 11, support block 12 and reinforcing rib 13 of the upper mold 10 are assembled by welding, and after welding, they are assembled with the 10,000-ton press. The support plate 21 and pull plate 22 of the lower mold 20 are assembled by connecting with blind hole pins 23.

[0105] After assembly, the mold is first aligned by measuring the gap between the upper mold 10 and the lower mold 20. 下模 =2400mm, upper die 10 arc plate width B 1 =1140mm, move the upper die 10 downward to the inner area of ​​the lower die 20, and when the gap between the arc plate of the upper die 10 and both sides of the lower die 20 is consistent at 630mm, the upper and lower dies 20 are aligned.

[0106] Then, the zero position is confirmed, that is, the bottom of the arc plate 11 of the upper die 10 is in contact with the top of the support plate 21 of the lower die 20 to set the zero position. Since the width of the arc plate 11 of the upper die 10 is much smaller than the width of the blank, the center of the blank, the upper die 10 and the lower die 20 must be strictly consistent when bending. If they are inconsistent, the bending trends of the two ends of the blank may be different, and even lateral sliding may occur, causing the mold to overturn. Therefore, the positioning stopper 25 is welded at a position of 1190mm from the center line of the lower die 20 on the support plate 21 of the lower die 20, that is, half of the blank width of 2380mm. When one side of the blank contacts the stopper before bending, it means that the blank is located in the center of the mold.

[0107] S3 forging forming: The prefabricated slab is kept at 1050-1100℃ in the heating furnace for 10 hours and then taken out of the furnace. The slab is clamped on the support plate 21 of the lower die 20, and the center positioning is completed after one side of the slab is close to the positioning block.

[0108] Start bending, and the bending process adopts a step-by-step pressing method, that is, press 100mm each time, pause briefly, and then press 100mm again, for a total of 12 times, and the total pressing amount is 100×12=1200mm.

[0109] During the bending process, pay attention to whether the deformation trends on both sides of the forging are consistent and whether the arc plate 11 of the upper die 10 fits the forging.

[0110] After the bending is completed, observe whether the forging and the lower die 20 pad are completely fitted. If they are completely fitted, it can be preliminarily determined that the forging size requirements are met.

[0111] 4. Dimension verification: Use the "three-point circle" principle to prepare a simple and fast measurement tool, see Fig. 9 , use two straight sample bars, distributed at 90 degrees to each other, and confirm the positions of the three points through the chord length calculation formula before welding. After the forging is bent, compare it with the measuring tool to observe whether the inner diameter of the forging meets the size requirements. If the size meets the requirements, it is completed.

[0112] It should be noted that the dimensions involved in the above embodiments should be increased with error margins during the actual processing, and for the convenience of processing, rounding or integeration is usually adopted, which does not affect the final product. This is a routine operation of technical personnel in this field.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A die for one-time die forging and bending of ultra-wide and ultra-thick arc forgings, characterized in that: Including upper die and lower die; The upper mold includes an arc-shaped plate, a support block arranged on the inner arc surface of the arc-shaped plate, and a plurality of reinforcing ribs arranged at the connection between the arc-shaped plate and the support block; The outer arc surface of the arc plate is used to form the inner arc surface of the forging, and R1 = (1.007-1.009) × R0, 0.6B0 ≤ B1 < B0, A1 = (0.05-0.15) A0 and A1 ≥ 60 mm; The support block is located in the width center area of ​​the arc-shaped plate and extends along the arc surface of the arc-shaped plate, B2 = (0.45-0.55) B1; The plurality of reinforcing ribs are evenly distributed at the connection between the arc plate and the support block, and are all oriented toward the center of the arc plate, the reinforcing ribs include adjacent first side edges and second side edges, the first side edges are connected to the support block, and the second side edges are connected to the arc plate, L3≥3A1, B3=(0.2-0.3)B1, A3=(0.45-0.55)A1, and the interval between two adjacent reinforcing ribs is 10-12°; The lower die comprises two supporting plates arranged opposite to each other, and a pulling plate connecting the sides of the two supporting plates, wherein the supporting plates are used to carry the blank along the length direction; Among them, the length, width and thickness of the rectangular blank are L0, B0 and A0 respectively; the outer arc radius, width and thickness of the curved plate are R1, B1 and A1 respectively; the length, width and thickness of the supporting block are L2, B2 and A2 respectively; the length, width and thickness of the reinforcing rib are L3, B3 and A3 respectively.

2. The mold according to claim 1, characterized in that: The yield strength of the arc plate and the support block is not less than 270 MPa; the yield strength of the reinforcing rib is not less than 225 MPa.

3. The mold according to claim 1, characterized in that: The pull plate and the support plate are connected by blind holes and pins, and φ1=φ0+1mm, L 盲孔 ≥ 2 / 3 L 插销 , L 插销 ≥550mm, of which, The diameter of the pin is φ0 and the length is L 插销 , the blind hole diameter is φ1 and the depth is L 盲孔 .

4. The mold according to claim 1, characterized in that: The lower die also includes a positioning block and a pad; The positioning block is arranged on the working surface of the support plate; The pad is arranged at the middle position of the two support plates and is used to fit the corresponding outer arc surface of the forging when the blank is bent into the forging.

5. A method for one-time die forging and bending of ultra-wide and ultra-thick arc-shaped forgings, characterized in that: A mold as described in any one of claims 1 to 4 is used, and the method comprises: S1 Prefabricated trapezoidal billet: Forged trapezoidal billet, and B 上底 =0.96×B0,B 下底 =1.05×B0, where the width of the rectangular blank section is B0, and the width of the upper base of the curved front cross section of the trapezoidal blank is B 上底 , the bottom width is B 下底 ; S2 mold assembly and positioning: the mold is manufactured according to the size of the rectangular blank, and the upper mold of the mold is assembled with the 10,000-ton press, and the relative positions of the upper mold and the lower mold of the mold are adjusted so that the upper mold and the lower mold are centered and zero position is confirmed; S3 forging forming: placing the trapezoidal blank on the lower die, and using the upper die to press the trapezoidal blank one by one.

6. The method according to claim 5, characterized in that Before the pressing in step S3, the trapezoidal billet is kept at 1050-1100°C for 8-12h.

7. The method according to claim 5, characterized in that Step S3, pressing step by step, refers to pressing down at intervals for multiple times, and each pressing amount is 100 mm, and the number of pressing times is 12 times.

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