A differential forging method and forming die for an arc-shaped forging.

Abstract

This invention discloses a differential forging method and forming die for arc-shaped forgings, belonging to the field of forging technology. Addressing the difficulties in forming arc-shaped forgings and the inconsistency between the fiber flow direction and the forging direction, this invention uses a trapezoidal straight billet for forging. The trapezoidal straight billet has a right-angled trapezoidal cross-section. The process includes: placing the trapezoidal straight billet between a combined elastic module and a lower flat anvil, gradually feeding it forward for forging, and repeating the feeding and forging operation to achieve elongation and bending. The trapezoidal straight billet adheres to the lower flat anvil with its right-angled waist surface. The combined elastic module includes multiple elastic dies arranged side-by-side along the inclined waist direction of the trapezoidal straight billet. During forging, the multiple elastic dies simultaneously contact the trapezoidal straight billet. This invention utilizes the difference in metal flow velocity on both sides of the trapezoidal straight billet to achieve billet bending, simplifying the forming process. Simultaneously, by using the combined elastic module to hinder the lateral flow of metal during billet elongation, the metal flows axially along the billet, ensuring the billet's radius of curvature.

Description

Technical Field

[0001] This invention relates to the field of forging, and more particularly to a differential forging method and forming die for arc-shaped forgings. Background Technology

[0002] Existing forging methods for curved forgings, such as Figure 2 As shown, the process involves forging a steel ingot into a wide plate forging capable of enveloping and covering the arc-shaped forging, and then machining it to the dimensions and shape of the arc-shaped forging. However, this method is difficult to form, results in a large machining allowance for the forging, extremely low material utilization, and the fiber structure direction of the forging is inconsistent with the direction of the arc-shaped component. This problem is particularly prominent for the special shape and huge size of ultra-large arc-shaped forgings.

[0003] Features of ultra-large flat cross-section arc forgings, such as Figure 1 As shown, the forging is characterized by an arc diameter greater than 8000mm, a cross-sectional width greater than 1600mm, a cross-sectional width-to-height ratio greater than 3, and an arc greater than 180°.

[0004] In response to the above problems, there are corresponding improvements in the existing technology. For example, Chinese patent application CN111346998A, published on June 30, 2020, discloses a method for preparing a cylindrical arc-shaped forging. The method includes: (1) forging slab: upsetting and drawing the ingot and forging it into a slab; (2) hot rolling steel billet: rolling the slab in multiple passes to obtain a hot-rolled flat and long steel billet; (3) local upsetting: using a local upsetting forming device to perform multiple passes of local upsetting on a local part of the flat and long steel billet, and then shaping and machining to obtain a cylindrical flat and long steel billet; (4) hot push bending forming: using a hot push bending forming equipment to perform segmented bending forming on the cylindrical flat and long steel billet, and finally obtaining a cylindrical arc-shaped forging; (5) performance heat treatment: the formed forging is subjected to performance heat treatment to meet the product performance requirements. This invention can efficiently form large cylindrical arc-shaped forgings, reduce machining allowances, improve material utilization, and obtain uniform grains and microstructure, ensuring the comprehensive performance of the forgings. The core technology of this solution lies in hot push bending. This technology requires continuous bending, which requires first heating the billet before the forming zone to above 1000°C rapidly, online, and continuously using a medium-frequency induction heating coil, as described in

[0083] of the specification. This means that high-temperature plastic forming is required, and the billet needs to be heated to a very high temperature across its entire cross-section in a short time. This method places high demands on the heating capacity of the induction heating coil. This method is feasible for hollow parts or parts with small cross-sectional dimensions. However, for ultra-large forgings with a cross-sectional width greater than 1600mm, the required induction heating coil power is extremely high, and the required medium-frequency induction heating coil equipment is very large and complex. At the same time, the space available for arranging the induction coil before the hot push bending forming zone is limited, making it difficult to meet the requirement of rapidly, online, and continuously heating the billet before the forming zone to above 1000°C using an induction heating coil. Therefore, this technical solution has extremely high requirements for the instantaneous power of the equipment, requires complex supporting equipment, and is not suitable for ultra-large arc-shaped forgings.

[0005] For example, Chinese patent application CN112008025A, published on December 1, 2020, discloses a free forging process and mold for large curved blade-type forgings, relating to the field of forging technology. The process includes: Step 1, using a rectangular billet as the initial blank, high-temperature free forging is performed using a convex anvil to obtain a dumbbell-shaped long billet; Step 2, the long billet is cut along the centerline to obtain two pre-formed billets with different thicknesses on both sides and a smooth transition; Step 3, a free forging final drawing mold with guide grooves and asymmetrical baffles on both sides is used to perform high-temperature forging and drawing of the cut pre-formed billets, reducing the material thickness of the outer region of the pre-formed billet and elongating it along the feeding direction, forcing the pre-formed billet to bend inward, thereby forming a large curved blade-type forging. Through the above-described free forging process and mold, the forging of large curved blade-type forgings is achieved, which can improve forging performance and material utilization, reduce equipment load, improve forging forming effect, and increase production efficiency. The technical solution has two problems: (1) The upper and lower surfaces of the billet are both inclined, especially the lower inclined surface, which makes it impossible to support the billet stably and effectively. It cannot be stable on the mold and is prone to tilting and rotating to one side when subjected to gravity or equipment pressure, causing the billet to twist during the final forging process. The curvature consistency and flatness of the forging are difficult to control and guarantee; (2) The forming surfaces of the upper and lower molds in the final forging process are two planes. When the forming mold contacts the billet, it only contacts the higher side of the billet first, and the lateral flow of the billet is unobstructed during the pressing process. According to the law of least resistance in metal plastic forming, the billet will preferentially flow from the high side to the low side. After both sides of the billet are in contact with the mold, the heights of the billets on both sides are nearly the same, allowing for effective flow along the axial direction. However, at this point, the inward bending force of the billet is insufficient. When the inward bending force is insufficient, the baffles on both sides not only fail to help the billet bend and form, but also block the billet because the flow direction of the billet is inconsistent with the flow direction of the baffles, causing it to get stuck in the mold cavity. According to our company's research on this process scheme, under this scheme, the actual bending angle of the billet can only reach about 90°, which is far from meeting the requirement of an arc greater than 180°. At the same time, the fiber structure of the forging is relatively disordered.

[0006] Therefore, it is necessary to propose further solutions to address at least one of the aforementioned problems. Summary of the Invention

[0007] To address the difficulties in forming curved forgings and the inconsistency between the fiber flow direction and its orientation, this invention provides a differential forging method and forming die for curved forgings. The technical solution is as follows:

[0008] A differential forging method for an arc-shaped forging uses a trapezoidal straight billet for forging. The trapezoidal straight billet has a right-angled trapezoidal cross-section. The method includes: placing the trapezoidal straight billet between a combined elastic module and a lower flat anvil, gradually feeding it forward for forging, and repeating the feeding and forging operation to achieve elongation and bending shaping.

[0009] The trapezoidal straight blank is fitted with the lower flat anvil with its right-angled waist surface;

[0010] The combined elastic module includes multiple elastic molds, which are arranged side by side along the inclined waist direction of the trapezoidal straight blank. When the multiple elastic molds forge the trapezoidal straight blank, they simultaneously contact the trapezoidal straight blank.

[0011] In a preferred embodiment of the present invention, the elastic mold, except for the elastic mold located on the highest side of the trapezoidal straight blank, includes an elastic element and a flat anvil connected to the elastic element. The flat anvil is used to contact the inclined waist surface of the trapezoidal straight blank, and the flat anvil is located in the deformation direction of the elastic element.

[0012] In a preferred embodiment of the present invention, a support mold is also employed, which is located above a plurality of elastic molds, and the plurality of elastic molds forge the trapezoidal straight blank under the drive of the support mold.

[0013] In a preferred embodiment of the present invention, the support mold includes a top surface and two side surfaces located on both sides of the top surface, and a plurality of elastic molds are located between the two side surfaces and arranged from one side surface to the other side surface.

[0014] In a preferred embodiment of the present invention, an upper and lower guide assembly is provided between the support mold and the lower anvil.

[0015] In a preferred embodiment of the present invention, the upper and lower guide components include guide posts disposed on the support mold and guide holes disposed at corresponding positions on the lower anvil, wherein the height direction of the guide posts and the depth direction of the guide holes are both consistent with the forging direction of the elastic mold.

[0016] In a preferred embodiment of the present invention, the natural heights of the plurality of elastic moduli satisfy:

[0017]

[0018] Where P1 and P2 are the lengths of the upper and lower bases of the trapezoidal cross-section of the trapezoidal straight blank, N is the number of elastic moduli, and T is the number of elastic moduli. n T1 is the height of the nth elastic modulus, where n is the order of elastic modulus sorted from low to high according to their natural height, and T1 is the height of the elastic modulus with the lowest natural height.

[0019] In a preferred embodiment of the present invention, N is between 3 and 8.

[0020] In a preferred embodiment of the present invention, the longitudinal width S of the contact surface between the plurality of elastic molds and the trapezoidal straight blank is consistent, and the feed amount M of each anvil during forward feeding is in... between.

[0021] Another technical solution is:

[0022] A forming die for a differential forging method applied to any of the above-described arc-shaped forgings includes a combined elastic module, wherein the combined elastic module includes multiple elastic molds arranged side by side and simultaneously contacting the blank during forging.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The present invention utilizes the difference in metal flow velocity on both sides of the trapezoidal straight billet to achieve billet bending, which is simple to form. At the same time, by using a combined elastic module to hinder the lateral flow of metal during the billet elongation process, the metal flows along the billet axis, ensuring the curvature radius of the billet.

[0025] (2) The present invention ensures that multiple elastic molds move synchronously through the support mold, and further ensures that the upper and lower molds effectively restrict the lateral flow of the billet and enhance the axial flow of the billet during the forging process by the upper and lower guide components set between the support mold and the lower anvil. At the same time, through the action of the guide hole and the guide column, it ensures that the tooling always runs on the designed track and ensures the cross-sectional shape of the forging. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of an ultra-large flat cross-section arc-shaped forging structure;

[0027] Figure 2 This is a schematic diagram of an existing forging method for flat-section arc-shaped forgings;

[0028] Figure 3 This is a schematic diagram of the drawing and feeding of an electroslag ingot, where T represents the riser end and B represents the bottom end;

[0029] Figure 4(a) is a schematic diagram of the mold structure;

[0030] Figure 4(b) is a schematic diagram of blank preparation by drawing out the mold;

[0031] Figure 4(c) is a schematic diagram of the structure of the trapezoidal straight blank obtained by drawing out the mold;

[0032] Figure 5 This is a schematic diagram illustrating the lengthening method used in this study;

[0033] Figure 6 This is a schematic diagram of the bending and forming method.

[0034] Specifically, 10. Trapezoidal straight billet; 20. Arc-shaped forging;

[0035] 100, Elastic mold; 200, Lower anvil; 300, Support mold; 310, Top surface; 320, Side surface. Detailed Implementation

[0036] The invention will be more readily understood by referring to the following detailed description of preferred embodiments and included examples. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of conflict, the definitions in this specification shall prevail. As used herein, the term "prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover a non-exclusive inclusion. For example, a composition, step, method, article, or apparatus comprising the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such a composition, step, method, article, or apparatus.

[0037] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0038] The singular form includes the plural objects of discussion unless the context clearly indicates otherwise. "Optional" or "any one" means that the matter or event described thereafter may or may not occur, and the description includes both the possibility that the event occurs and the possibility that the event does not occur.

[0039] Approximate terms used in the specification and claims to modify quantities indicate that the invention is not limited to that specific quantity, but also includes acceptable modifications close to that quantity that do not alter the relevant essential function. Correspondingly, the use of "about," "approximately," etc., to modify a numerical value means that the invention is not limited to that precise value. In some instances, approximate terms may correspond to the precision of the instrument used to measure the value. In this application's specification and claims, scope definitions can be combined and / or interchanged, unless otherwise stated, these scopes include all subscopes contained therein.

[0040] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of this invention do not impose any limitation on the quantity requirement (i.e., the number of times) of the elements or components. Therefore, “an” or “a” should be interpreted as including one or at least one, and the singular form of an element or component also includes the plural form, unless the quantity clearly refers to the singular form.

[0041] Example 1:

[0042] A differential forging method for an arc-shaped forging is disclosed, which uses a trapezoidal straight billet 10 as shown in Figure 4(c) for forging. The cross-section of the trapezoidal straight billet 10 is a right trapezoid. Furthermore, in this embodiment, the formed forging is an ultra-large flat-section arc-shaped forging, and its dimensional requirements are as follows... Figure 1 As shown.

[0043] The trapezoidal straight blank 10 can be produced by drawing with a die, specifically:

[0044] S1 material cutting: as shown Figure 3 As shown, the electroslag ingot is lightly pressed and rolled into a round shape, then the ingot body is drawn out, and the riser end is pressed with clamps to draw the steel ingot into a cylindrical blank with an ingot height-to-diameter ratio of less than 2.

[0045] S2 blank preparation: such as Figures 4(a)-4(c) As shown, a trapezoidal billet 10 with a right-angled trapezoidal cross-section is formed through upsetting, drawing, and die drawing. The dimensions of the trapezoidal billet 10 and the final formed arc-shaped forging 20 satisfy the following:

[0046]

[0047] P1 = (1.05 ~ 1.1)M

[0048] P1 and P2 are the lengths of the upper and lower bases of the trapezoidal cross section of the trapezoidal straight billet, Q is the thickness of the trapezoidal straight billet, and L is the length of the trapezoidal straight billet.

[0049] D1 is the outer diameter of the arc-shaped forging, D2 is the inner diameter of the arc-shaped forging, M is the thickness of the arc-shaped forging, and θ is the curvature of the arc-shaped forging.

[0050] γ is the loss value, which is the billet loss caused by heating oxidation, burning, cracking, and cleaning of scale during the forging process. γ is usually around 1% to 4%, but the actual value will vary depending on the on-site production process.

[0051] The trapezoidal straight billet 10 is then drawn longer. The billet bending is achieved by utilizing the difference in metal flow velocity on both sides of the billet 10. Specifically, the metal is drawn faster on the higher side of the billet 10, and slower on the lower side. This difference in metal flow velocity causes the billet to naturally bend towards the lower side during the drawing process. Simultaneously, a combined elastic module is used to impede the lateral flow of metal during the drawing process, ensuring that the metal flows along the axial direction of the billet and maintaining the billet's radius of curvature. Specifically: [Example...] Figure 5 and Figure 6 As shown, the trapezoidal straight blank 10 is placed between the combined elastic module and the lower flat anvil 200, and is fed forward for forging step by step, and the feeding and forging operation is repeated to achieve elongation and bending.

[0052] like Figure 5 As shown, the trapezoidal straight billet 10 is placed against the lower flat anvil 200 with its right-angled waist surface, that is, the trapezoidal straight billet 10 is placed vertically on the lower flat anvil 200 to keep it in a stable state. At the same time, it can be understood that forward feeding means feeding forward along its length direction, thereby forging the trapezoidal straight billet 10 into an arc-shaped forging 20.

[0053] The combined elastic module includes multiple elastic modules 100, which are arranged side by side along the inclined waist direction of the trapezoidal straight blank 10. That is, the multiple elastic modules 100 are arranged sequentially along the inclined waist of the right-angled trapezoidal section of the trapezoidal straight blank 10, or in other words, the multiple elastic modules 100 are arranged sequentially along a direction perpendicular to the length direction of the trapezoidal straight blank 10.

[0054] When multiple elastic dies 100 are forged against the trapezoidal straight blank 10, they simultaneously contact the trapezoidal straight blank 10. In this embodiment, the upper ends of the multiple elastic dies 100 are flush, and the lower ends are adapted to the inclined waist of the trapezoidal straight blank 10. That is, the natural height of the multiple elastic dies 100 decreases sequentially from low to high along the inclined waist of the trapezoidal straight blank 10, and the slope of the combined elastic die group is the same as the slope of the inclined surface of the trapezoidal straight blank 10. The natural height of the elastic die 100 refers to the height of the elastic die 100 in its free state.

[0055] Preferably, the natural heights of the plurality of elastic moduli 100 satisfy:

[0056]

[0057] Where P1 and P2 are the lengths of the upper and lower bases of the trapezoidal cross-section of the trapezoidal straight blank, N is the number of elastic moduli of 100, and T is the length of the upper and lower bases of the trapezoidal straight blank. n T1 is the height of the nth elastic modulus 100, where n is the order of elastic moduli from lowest to highest natural height, and T1 is the height of the elastic modulus with the lowest natural height. N is between 3 and 8, and more preferably N is 5.

[0058] Except for the elastic mold 100 located on the highest side of the trapezoidal straight blank 10, the elastic mold 100 includes an elastic element and a flat anvil connected to the elastic element. The flat anvil is used to contact the inclined waist surface of the trapezoidal straight blank 10, and the flat anvil is located in the deformation direction of the elastic element. Taking a combination of 5 elastic molds 100 as an example, the combined elastic mold group from the high side to the low side of the trapezoidal straight blank 10 includes a first elastic mold with a height of T1; a second elastic mold with a height of T2; a third elastic mold with a height of T3; a fourth elastic mold with a height of T4; and a fifth elastic mold with a height of T5. The second to fifth elastic molds are connected by elastic elements and flat anvils. The elastic element can be a spring or other equivalent elastic structural element. The first elastic mold can also be connected by elastic elements and flat anvils. However, since the deformation of the highest side of the trapezoidal straight blank 10 is the largest, and the lower ends of the five elastic molds 100 are flush during final forming, the first elastic mold preferably has an elasticity of 0, that is, it is a rigid mold, and a flat anvil can be directly used. It is understandable that the elastic elements in the five elastic molds 100 have different lengths. The five elastic molds 100 can use flat anvils with the same working surface size, which is the contact surface with the trapezoidal straight blank 10.

[0059] In this embodiment, the combined elastic module consists of five elastic molds 100 with gradually increasing rigidity from left to right, with the fifth one from the right being the rigid mold. During the forging of the trapezoidal cross-section billet, the combined elastic module simultaneously contacts and compresses different positions on the inclined surface of the trapezoidal straight billet 10, causing synchronous deformation in different areas of the billet. Simultaneously, the elastic molds 100 can prevent the lateral flow of metal from the higher side to the lower side, ensuring that the metal on the higher side flows axially to maintain the speed difference between the two sides. During the pressing process, the elastic molds 100 are subjected to continuously increasing metal resistance until the four elastic molds 100 on the left are finally compressed to the same height as the rigid mold on the right, resulting in a rectangular cross-section for the forging. That is, when the forging thickness is reached, the combined elastic module is simultaneously compressed to the same height, making the surface of the forged billet smooth.

[0060] To ensure the synchronous movement of multiple elastic molds 100, this method also employs a support mold 300, which is located above the multiple elastic molds 100. The multiple elastic molds 100 forge the trapezoidal straight billet 10 under the action of the support mold 300. The support mold 300 includes a top surface 310 and two side surfaces 320 located on either side of the top surface 310. The multiple elastic molds 100 are located between the two side surfaces 320 and arranged from one side surface 320 to the other, thereby confining the elastic molds 100 within the space formed by the top surface 310 and the two side surfaces 320.

[0061] Preferably, an upper and lower guide assembly is provided between the support mold 300 and the lower anvil 200 to ensure that during the pressing down and return stroke of the combined elastic mold, the upper and lower molds effectively restrict the lateral flow of the billet and enhance the axial flow of the billet during the forging process. Simultaneously, it ensures that the tooling always runs on the designed track, ensuring the cross-sectional shape of the forging. Specifically, the upper and lower guide assembly may include guide posts disposed on the support mold 300 and guide holes disposed at corresponding positions on the lower anvil 200. The height direction of the guide posts and the depth direction of the guide holes are both consistent with the forging direction of the elastic mold 100.

[0062] In this method, the longitudinal width S of the contact surface between multiple elastic moduli 100 and the trapezoidal straight blank 10 is consistent, and the feed amount M of each anvil during forward feeding is within... This allows the billet to flow more easily along the axial direction during plastic deformation. The longitudinal width of the elastic mold 100 is the width of its side 320 parallel to the billet feeding direction.

[0063] In this embodiment, the longitudinal width of the elastic mold 100 is the same as the longitudinal width of the support mold 300. Figure 6 The longitudinal width of the support mold 300 is shown to be S, and the elastic mold 100 is located directly below the support mold 300, and its longitudinal width is also S.

[0064] Example 2:

[0065] A forming die is used in Example 1. The die includes a combined elastic module, which includes multiple elastic molds 100 arranged side by side and simultaneously contacting the blank during forging.

[0066] Multiple elastic molds 100 can be configured such that their upper ends are flush with each other, their lower ends are stepped, and their slopes are the same as the slopes of the forging surface of the billet, that is, the same as the slopes of the inclined surface of the trapezoidal straight billet 10.

[0067] The natural height of multiple elastic moduli 100s satisfies:

[0068]

[0069] Where P1 and P2 are the lengths of the upper and lower bases of the trapezoidal cross-section of the trapezoidal blank, N is the number of elastic moduli of 100, and T is the length of the cross-section of the trapezoidal blank. n T1 represents the height of the nth elastic modulus 100, where n is the order of elastic moduli from lowest to highest natural height, and T1 is the height of the elastic modulus with the lowest natural height. N is between 3 and 8, and more preferably N is 5.

[0070] Except for the elastic mold 100 located on the highest side of the billet, each elastic mold 100 includes an elastic element and a flat anvil connected to the elastic element. The flat anvil is used to contact the billet and is located in the deformation direction of the elastic element. Taking a combination of five elastic molds 100 as an example, the combined elastic mold group, from the high side to the low side of the billet, includes a first elastic mold with a height of T1; a second elastic mold with a height of T2; a third elastic mold with a height of T3; a fourth elastic mold with a height of T4; and a fifth elastic mold with a height of T5. The second to fifth elastic molds are connected by elastic elements and flat anvils. The elastic elements can be springs or other equivalent elastic structural elements. The first elastic mold can also be connected by elastic elements and flat anvils. However, since the deformation of the highest side of the billet is the largest, and the lower ends of the five elastic molds 100 are flush during final forming, the first elastic mold preferably has zero elasticity, i.e., it is a rigid mold and can directly use a flat anvil. It is understood that the lengths of the elastic elements in the five elastic molds 100 are different. Five elastic molds 100 can use flat anvils with the same working surface size, which is the contact surface with the blank.

[0071] In this embodiment, the combined elastic module consists of five elastic molds 100 with gradually increasing rigidity from left to right, with the fifth one from the right being the rigid mold. During the forging of the billet, the combined elastic module simultaneously contacts and compresses different positions on the inclined surface of the billet, causing different areas of the billet to deform synchronously. At the same time, the elastic molds 100 can prevent the lateral flow of metal from the high side to the low side, ensuring that the metal on the high side flows axially to maintain the speed difference of the metal flow on both sides. During the pressing process, the elastic molds 100 are subjected to continuously increasing metal resistance until the four elastic molds 100 on the left are finally compressed to the same height as the rigid mold on the right, making the cross-section of the forging rectangular. That is, when the forging thickness is reached, the combined elastic module is simultaneously compressed to the same height, making the surface of the forged billet flat.

[0072] To ensure the synchronous movement of multiple elastic molds 100, this mold also includes a support mold 300, which is located above the multiple elastic molds 100. The multiple elastic molds 100 forge the blank under the action of the support mold 300. The support mold 300 includes a top surface 310 and two side surfaces 320 located on both sides of the top surface 310. The multiple elastic molds 100 are located between the two side surfaces 320 and are arranged from one side surface 320 to the other side surface 320, thereby confining the elastic molds 100 within the space formed by the top surface 310 and the two side surfaces 320.

[0073] Preferably, an upper and lower guide assembly is provided between the support mold 300 and the lower anvil 200 to ensure that during the pressing down and return stroke of the combined elastic mold, the upper and lower molds effectively restrict the lateral flow of the billet and enhance the axial flow of the billet during the forging process. Simultaneously, it ensures that the tooling always runs on the designed track, ensuring the cross-sectional shape of the forging. Specifically, the upper and lower guide assembly may include guide posts disposed on the support mold 300 and guide holes disposed at corresponding positions on the lower anvil 200. The height direction of the guide posts and the depth direction of the guide holes are both consistent with the forging direction of the elastic mold 100.

[0074] In summary, this invention utilizes the difference in metal flow velocity on both sides of a trapezoidal straight billet to achieve billet bending. At the same time, by using a combined elastic module to hinder the lateral flow of metal during the billet drawing process, the metal flows along the axial direction of the billet, ensuring the billet's radius of curvature.

[0075] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A differential forging method for an arc-shaped forging, characterized in that, Forging is performed using a trapezoidal straight billet, the cross-section of which is a right-angled trapezoid. The process includes: placing the trapezoidal straight billet between a combined elastic module and a lower flat anvil, gradually feeding it forward for forging, and repeating the feeding and forging operation to achieve elongation and bending shaping. The trapezoidal straight blank is fitted with the lower flat anvil with its right-angled waist surface; The combined elastic module includes multiple elastic molds, which are arranged side by side along the inclined waist direction of the trapezoidal straight blank. When the multiple elastic molds forge the trapezoidal straight blank, they simultaneously contact the trapezoidal straight blank.

2. The differential forging method for arc-shaped forgings according to claim 1, characterized in that, The elastic mold, except for the elastic mold located on the highest side of the trapezoidal straight blank, includes an elastic element and a flat anvil connected to the elastic element. The flat anvil is used to contact the inclined waist surface of the trapezoidal straight blank and is located in the deformation direction of the elastic element.

3. The differential forging method for arc-shaped forgings according to claim 1, characterized in that, A support mold is also used, which is located above a plurality of elastic molds, and the plurality of elastic molds forge the trapezoidal straight blank under the drive of the support mold.

4. The differential forging method for arc-shaped forgings according to claim 3, characterized in that, The support mold includes a top surface and two side surfaces located on both sides of the top surface, and a plurality of elastic molds are located between the two side surfaces and arranged from one side surface to the other side surface.

5. The differential forging method for arc-shaped forgings according to claim 3, characterized in that, An upper and lower guide assembly is provided between the support mold and the lower anvil.

6. The differential forging method for arc-shaped forgings according to claim 5, characterized in that, The upper and lower guide components include guide posts disposed on the support mold and guide holes disposed at corresponding positions on the lower anvil. The height direction of the guide posts and the depth direction of the guide holes are both consistent with the forging direction of the elastic mold.

7. The differential forging method for arc-shaped forgings according to claim 1, characterized in that, The natural heights of the plurality of elastic moduli satisfy: Where P1 and P2 are the lengths of the upper and lower bases of the trapezoidal cross-section of the trapezoidal straight blank, N is the number of elastic moduli, and T is the number of elastic moduli. n T1 is the height of the nth elastic modulus, where n is the order of elastic modulus sorted from low to high according to their natural height, and T1 is the height of the elastic modulus with the lowest natural height.

8. The differential forging method for arc-shaped forgings according to claim 7, characterized in that, N is between 3 and 8.

9. The differential forging method for arc-shaped forgings according to claim 1, characterized in that, The longitudinal width S of the contact surface between the multiple elastic molds and the trapezoidal straight blank is consistent, and the feed amount M of each anvil during forward feeding is within... between.

10. A forming die for a differential forging method applied to the arc-shaped forging of any one of claims 1-9, characterized in that, It includes a combined elastic module, which comprises multiple elastic molds arranged side by side and simultaneously contacting the blank during forging.

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