A method of forging an "L" shaped large sheet forging

Abstract

The present application belongs to the field of forging technology, and particularly relates to a forging method of an L-shaped large thin plate forging. The method realizes qualified output of the L-shaped large thin plate forging by using a special bending tool and an L-shaped die, and combining free forging and die membrane forging, and solves the blank of the forging technology of the L-shaped large thin plate forging.

Description

Technical Field

[0001] This invention belongs to the field of forging technology, and particularly relates to a forging method for an "L"-shaped large thin plate forging. Background Technology

[0002] With the rapid development of the aviation industry, forging shapes are becoming increasingly complex. Traditional L-shaped forging methods can only produce some relatively thick forgings, which employs bending and shaping methods, involves numerous heat treatments, and requires repeated adjustments using molds. Traditional methods cannot produce large, thin "L"-shaped forgings with a width-to-height ratio ≥ 4. Summary of the Invention

[0003] Purpose of the invention: To provide a forging method for "L"-shaped large thin plate forgings, which uses a combination of free forging and die forging to achieve qualified production of "L"-shaped large thin plate forgings by using a special bending fixture and an L-shaped die, thus filling the gap in forging technology for "L"-shaped large thin plate forgings.

[0004] Technical solution:

[0005] A forging method for an "L"-shaped large thin plate forging, wherein the total length of the "L"-shaped outer contour of the forging is A, the width is B, and the thickness is C; wherein 60mm≤C≤90mm, 20C≤A≤30C, 4C≤B≤6C, and the "L"-shaped corner is 90°, the method includes:

[0006] Step 1: Heat the bar stock to the deformation temperature and forge it into a rectangular first blank with length, width and thickness a, b and c respectively, and a = (0.5~0.7)A, b = (0.7~0.9)B, c = (1.8~2.2)C;

[0007] Step 2: Set two material sections with a length of d at both ends of the first blank length a, where d = (1 / 7 to 1 / 8)a. Press the two material sections thin to a height of (4 / 5 to 9 / 10)c to obtain the second blank;

[0008] Step 3: After heating the second blank to the deformation temperature, place the a×c surface flat on a 90° V-shaped fixture, with the length a spanning across the V-shaped fixture, and the center of the a direction aligned with the lowest point of the V-shaped fixture on a vertical line; place a semi-circular pad at the center of the blank, and press the semi-circular pad to bend the second blank. During the pressing process, the semi-circular pad moves within a range of (1 / 3 to 2 / 3)a on the second blank; the bending process is divided into three stages, using a first semi-circular pad, a second semi-circular pad, and a third semi-circular pad with different radii for each stage; in the first stage, the first semi-circular pad is used to bend the second blank to an angle of 140 to 150°; in the second stage, the second semi-circular pad is used to bend the second blank to an angle of 110 to 120°; and in the third stage, the third semi-circular pad is used to bend the second blank to an angle of 90° to obtain the third blank.

[0009] Step 4: Use a fan-shaped steel plate to thin the protruding part of the corner of the third blank until the height is (4 / 5 to 9 / 10)c to obtain an L-shaped blank;

[0010] Step 5: Compare the L-shaped blank with the L-shaped template. If the template can cover the L-shaped blank and the distance between the outline of the L-shaped blank and the outline of the template is ≤10mm, the L-shaped blank is qualified. Otherwise, the blank should be shaped until it is qualified.

[0011] Step 6: After heating the L-shaped billet to the deformation temperature, place it in a special L-shaped die and press it to obtain an L-shaped forging; the die forging is divided into two heats: local pressing is adopted, the first heat pressing height is (1.2~1.6)C, and the second heat pressing until the forging fills the cavity.

[0012] Furthermore, step one also includes: b≤2c.

[0013] Furthermore, in step six, the L-shaped mold is designed based on the dimensions of the L-shaped forging. The width of the L-shaped mold cavity is (1 + material thermal shrinkage rate) × B, the depth is (1 + material thermal shrinkage rate) × C, the outer contour length is (1 + material thermal shrinkage rate) × A, the draft angle is 5°, the edge chamfer is R10, and the L-shaped mold is an open mold.

[0014] Furthermore, in step three, the V-shaped fixture is to machine a 90° V-shaped groove on the block base, with the V-shaped cross-section having a length of (0.4~0.5)A, a height of (0.2~0.3)A, and a groove depth of (0.15~0.2)A.

[0015] Furthermore, in step three, the semi-circular pad is a pad with a semi-circular cross-section and a length of L, and L = (3~5)C; and the radius of the third semi-circular pad is equal to the radius of the inner corner of the L-shaped blank bend, the radius of the second semi-circular pad is 4 / 5 of the radius of the third semi-circular pad, and the radius of the first semi-circular pad is 3 / 5 of the radius of the third semi-circular pad.

[0016] Furthermore, in step four, the thickness of the sector-shaped steel plate is 10mm, the central angle of the sector is 65°, and the horizontal projection completely coincides with the horizontal projection at the corner of the L-shaped billet.

[0017] Furthermore, in step five, the L-shaped template is made of a 3mm thick steel plate, with a horizontal projected area smaller than that of the L-shaped forging, and its edge is 15-25mm away from the edge of the L-shaped forging. Several holes with a diameter of 2 / 3 of the template width are machined on it, and the distance between the holes is 1 / 3R.

[0018] Furthermore, one end of the L-shaped mold is open along its length.

[0019] Beneficial effects:

[0020] The "L"-shaped large thin plate forgings produced using this method are simple and easy to control. Furthermore, the V-shaped tooling, semi-circular spacer, fan-shaped steel plate, and L-shaped template designed in this scheme facilitate the realization of the L-shaped blank, reducing the number of forging passes and avoiding repeated finishing. Open-form forging helps to conceal the external dimensions of the L-shaped forgings. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the first blank and the material division section provided by the present invention.

[0022] Figure 2 This is a schematic diagram of the second blank of the present invention.

[0023] Figure 3 This is a schematic diagram of the bending of the second blank of the present invention.

[0024] Figure 4 This is a schematic diagram of the thinning of the fan-shaped steel plate according to the present invention.

[0025] Figure 5 This is a schematic diagram of the L-shaped template of the present invention.

[0026] Figure 6 This is a schematic diagram of the L-shaped blank of the present invention.

[0027] Figure 7 This is a schematic diagram of the fetal membrane of the present invention.

[0028] Figure 8 This is a drawing of the forging of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The various features of embodiments of the present invention will now be described in detail. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can also be practiced without these specific details. The following description of the embodiments is merely intended to provide a better understanding of the invention by illustrating examples. The invention is not limited to any specific setups and methods provided below, but covers all improvements, substitutions, etc., to product structures and methods without departing from the spirit of the invention.

[0031] The "L"-shaped outer contour targeted by this invention has a total length of A, a width of B, and a thickness of C; wherein 60mm≤C≤90mm, 20C≤A≤30C, 4C≤B≤6C, and the "L"-shaped corner is 90°.

[0032] This invention first designs an L-shaped blank and an L-shaped die based on the shape characteristics of the L-shaped large thin plate forging. By combining free forging and die forging, the precise forming of the forging is ensured, while also ensuring the streamline direction of the forging.

[0033] To achieve the above objectives, the present invention also utilizes bending fixtures (90° V-shaped fixtures, semi-circular pads), fan-shaped steel plates, and other fixtures in combination with free forging and drawing steps such as lengthening and widening to obtain an L-shaped blank. Then, an L-shaped open die is used to perform die forging on the L-shaped blank to obtain an L-shaped forging.

[0034] This invention provides a method for forming an "L"-shaped thin plate forging, comprising: freely forging a first blank; pressing the first blank thin to obtain a second blank; bending the second blank to obtain an L-shaped blank; and forging the L-shaped blank using a die to obtain an L-shaped forging. The specific steps are as follows:

[0035] Step 1: Design the L-shaped die and L-shaped blank according to the external dimensions of the L-shaped forging.

[0036] The total length of the “L”-shaped outer contour is A, the width is B, and the thickness is C; where 60mm≤C≤90mm, 20C≤A≤30C, 4C≤B≤6C, and the corner of the “L” shape is 90°.

[0037] First, the L-shaped die is designed based on the dimensions of the L-shaped forging. The width of the L-shaped die cavity is (1 + material thermal shrinkage rate) × B, the depth is (1 + material thermal shrinkage rate) × C, the outer contour length is (1 + material thermal shrinkage rate) × A, the draft angle is 5°, the edge chamfer is R10, and one end of the L-shaped die is open. This design is conducive to the excess metal flowing out from the open end during die forging, thus ensuring the thickness of the L-shaped forging.

[0038] Secondly, the L-shaped blank is designed based on the outer dimensions of the L-shaped forging, and the design is based on the outer dimensions of the forging + 5mm underpressure volume conversion. The horizontal projection area of ​​the L-shaped blank is smaller than the horizontal projection area of ​​the L-shaped forging, and the edge distance is 15-30mm from the edge of the L-shaped forging. The height is (1.5-1.8)C.

[0039] Step 2: Design V-shaped fixtures, semi-circular pads, fan-shaped steel plates, and L-shaped templates based on the L-shaped blank.

[0040] The V-shaped fixture is a 90° V-shaped groove machined on a square base, with a V-shaped cross-section of (0.4~0.5)A in length, (0.2~0.3)A in height, and (0.15~0.2)A in depth.

[0041] The semicircular pad is a pad with a semicircular cross-section and a length of L, where L = (3~5)C; and the radius of the third semicircular pad is equal to the radius of the inner corner of the L-shaped blank bend, the radius of the second semicircular pad is 4 / 5 of the radius of the third semicircular pad, and the radius of the first semicircular pad is 3 / 5 of the radius of the third semicircular pad.

[0042] The specialized fan-shaped steel plate is designed for L-shaped blanks. With a thickness of 10mm, the 10mm fan-shaped steel plate effectively prevents deformation when the L-shaped blank is thinned. The central angle of the fan is 65°, and its horizontal projection completely coincides with the horizontal projection at the corner of the L-shaped blank. The fan-shaped steel plate completely covers the protrusions generated when the second blank is bent. This design ensures that the metal flows along the inner and outer arc directions at the corner, effectively preventing folds at the inner diameter bend and ensuring full filling at the outer diameter of the corner.

[0043] The L-shaped template is designed based on an L-shaped blank. It is made of 3mm thick steel plate, with a horizontal projected area smaller than that of the L-shaped forging. The edge of the template is 15-25mm from the edge of the L-shaped forging. Several holes with a diameter of 2 / 3 of the template width are machined on it, with a spacing of 1 / 3R between the holes. These machined holes effectively reduce the template's weight and facilitate handling when checking the dimensions of the L-shaped blank.

[0044] Step 3: Heat the bar stock to the deformation temperature and freely forge the billet to obtain the first rectangular blank (e.g., Figure 1), whose length, width and thickness are a, b and c respectively, and a = (0.5~0.7)A, b = (0.7~0.9)B, c = (1.8~2.2)C, b≤2c.

[0045] Step 4: Set two material dividing sections of length d at both ends of the first blank along the length 'a' direction, where d = (1 / 7 to 1 / 8)a. Compress the two material dividing sections to a height of (4 / 5 to 9 / 10)c to obtain the second blank (e.g., ...). Figure 2 ).

[0046] Step 5: After heating the second blank to the deformation temperature, place the a×c surface flat on the 90° V-shaped fixture, with the length a spanning across the V-shaped fixture, and the center of the a direction aligned with the lowest point of the V-shaped fixture on a vertical line; place the semi-circular pad at the center of the blank, and press the semi-circular pad to bend the second blank (e.g., ...). Figure 3 During the pressing process, the semi-circular pad moves within a range of (1 / 3 to 2 / 3)a on the second blank. The bending process is divided into three heats, and the pads used in the three heats are the first semi-circular pad, the second semi-circular pad, and the third semi-circular pad, respectively. In the first heat, the first semi-circular pad is used to bend the second blank to an angle of 140 to 150°. In the second heat, the second semi-circular pad is used to bend the second blank to an angle of 110 to 120°. In the third heat, the third semi-circular pad is used to bend the second blank to an angle of 90°. The resulting third blank has a protrusion at its corner.

[0047] Step Six: Use a special fan-shaped steel plate to thin the protruding corner of the third blank (e.g., Figure 4 ), to a height of (4 / 5~9 / 10)c to obtain an L-shaped blank (such as Figure 6 The purpose of using fan-shaped steel plates is to facilitate the flow of metal along the inner and outer arcs at the corners, effectively prevent folding at the inner diameter bends, and ensure the filling at the outer diameter of the corners.

[0048] Step 7: Use a special L-shaped template (such as...) Figure 5 The template is compared with the L-shaped blank. If the template can cover the L-shaped blank and the distance between the L-shaped blank outline and the template outline is ≤10mm, the L-shaped blank is qualified. Otherwise, the blank should be shaped until it is qualified.

[0049] Step 8: After heating the L-shaped blank to the deformation temperature, place it on a special L-shaped molding sheet (such as...). Figure 7 L-shaped forgings (such as) are obtained by pressing in the process. Figure 8 The forging process involves two heats: due to the large size of the forging, local pressing is adopted. The first heat is pressed to a height of (1.2~1.6)C, and the second heat is pressed until the forging fills the cavity.

[0050] The method of heating the bar stock to the deformation temperature and freely forging the billet to obtain a rectangular blank also includes: b≤2c, this design is beneficial to the subsequent bending step, if b>2c, it cannot be bent and will cause pinching at the bending point, and the material will be pulled on both sides.

[0051] The two material sections are pressed thin to a height of (4 / 5 to 9 / 10)c. During the subsequent forging of the mold, the material is not easy to move in the width direction at both ends. Pressing the width in advance is beneficial for filling the mold.

[0052] Example 1:

[0053] Step 1: Design the L-shaped die and L-shaped blank according to the external dimensions of the L-shaped forging.

[0054] First, based on the dimensions of the L-shaped forging, an L-shaped mold is designed. The width of the L-shaped mold cavity is (1+1%)×420mm=424mm, the depth is (1+1%)×90mm=91mm, the outer contour length is (1+1%)×1930mm=1949mm, the draft angle is 5°, the edge chamfer is R10, and one end of the L-shaped mold is open.

[0055] Secondly, based on the external dimensions of the L-shaped forging, an L-shaped blank is designed with the following dimensions: length = 1930mm - 20mm × 2 = 1890mm, width = 420mm - 20mm × 2 = 380mm, height = 1.8 × 90 = 162mm, inner arc radius at the corner is 140mm, and outer arc radius at the corner is 400mm.

[0056] Step 2: Design V-shaped tooling, semi-circular pads, fan-shaped steel plates, and L-shaped templates based on the L-shaped standard billet.

[0057] The V-shaped fixture is a 90° V-shaped groove machined on a square base. The V-shaped cross-section has a length of 0.45×1930mm=870mm, a height of 0.3×1930mm=580mm, and a groove depth of 0.2×1930mm=386mm.

[0058] The semicircular pad is a pad with a semicircular cross-section and a length of L, where L = 4C = 4 × 90 = 360 mm; and the radius R of the third semicircular pad is 140, the radius R of the second semicircular pad is 140 × 4 / 5 = 112 mm, and the radius R of the first semicircular pad is 140 × 3 / 5 = 84 mm.

[0059] The special fan-shaped steel plate designed according to the L-shaped billet has a thickness of 10mm, a central angle of 65°, an inner arc radius of 140, and an outer arc radius of 400.

[0060] Based on the design of the L-shaped forging, an L-shaped template is made of 3mm thick steel plate. The outer contour length is 1890mm, the width is 380mm, the inner arc radius at the corner is 140mm, and the outer arc radius at the corner is 400mm. There are 6 holes with a diameter of 280mm on top, and the distance between the holes is 93mm.

[0061] Step 3: Heat the bar stock to the deformation temperature and freely forge the billet to obtain the first rectangular blank.

[0062] First heating: Put the Φ300×1210 titanium alloy bar into the electric furnace for heating. The heating temperature is 945℃ below the phase transformation point, and the holding time is 240min.

[0063] Φ300×1210 is first riveted and then upset to ~Φ338×950±10;

[0064] ~Φ338×950±10, elongated and shaped to 250±3×350±3×~978;

[0065] Note: When drawing, the feed amount is 150-180mm, the pressing amount is ≤35, and after each pressing, it needs to be flipped 90°. Superimposed deformation is not allowed.

[0066] Second heating: The 250±3×350±3×~978 billet is placed in the electric furnace for heating at a temperature of 945℃ and a holding time of 200min.

[0067] The first rough blank is obtained by stretching and shaping the material from 250±350±3×~978 to 185±3×330+100×~1200.

[0068] Note: When drawing, the feed amount is 120-150mm, and the pressing amount is ≤30mm. After each pressing, the surface must be flipped 90°. Superimposed deformation is not allowed.

[0069] Step 4: Thin the end of the first blank to obtain the second blank. Place the 185±3×330+10 0×~1200 blank into an electric furnace for heating at 945℃ for 200min.

[0070] After the 385 area at both ends of 185±3×330+10 0×~1200 is thinned to 150, the width is adjusted to obtain the second blank.

[0071] Step 5, bending the second blank to obtain an L-shaped blank, includes three firing processes:

[0072] First heating: The second blank is placed in an electric furnace for heating at a temperature of 945℃ and a holding time of 150min.

[0073] The second blank is laid flat on the 90° V-shaped fixture with its length × height surface, and the length direction spans across the V-shaped fixture. The center of the length direction and the lowest point of the V-shaped fixture are on the same vertical line. A semi-circular pad is placed at the center of the blank, and the first semi-circular pad is pressed to bend the second blank to an angle of 140-150°. During the pressing process, the U-shaped pad moves within 800mm of the center of the length on the second blank.

[0074] Second heating: The billet is placed in an electric furnace for heating at a temperature of 945℃ and a holding time of 150min.

[0075] Place the billet on a 90° V-shaped fixture, place a semi-circular pad at the center of the billet, and press the U-shaped pad 2 to bend the billet to an angle of 110-120°. During the pressing process, the second semi-circular pad moves within a 600mm range of the center of the billet.

[0076] Third heat: The billet is heated in an electric furnace at a temperature of 945℃ for 150 minutes.

[0077] Place the billet on a 90° V-shaped fixture, place a semi-circular pad at the center of the billet, and press the third semi-circular pad to bend the second billet to an angle of 90° to obtain an L-shaped billet. During the pressing process, the third semi-circular pad moves within a 600mm range of the center of the billet.

[0078] The resulting L-shaped billet has a raised section at the bend. The L-shaped billet is then placed flat on a hammer anvil, and a special fan-shaped steel plate is placed on the raised section to thin it to 150mm.

[0079] Step 6: Compare the L-shaped blank with a special L-shaped template. If the template can cover the L-shaped blank and the distance between the outline of the L-shaped blank and the outline of the template is 6-10mm, the L-shaped blank is qualified.

[0080] Step 7: After heating the L-shaped billet to the deformation temperature, place it in a special L-shaped die and press it to obtain an L-shaped forging.

[0081] First forging: The L-shaped billet is heated in an electric furnace at a temperature of 945℃ for 100 minutes. After heating and holding, the L-shaped billet is placed on a die and pressed at a speed of 4 mm / s until the forging thickness is 130 ± 2 mm. The final forging temperature is ≤ 800℃.

[0082] Second heating: The L-shaped billet is heated in an electric furnace at a temperature of 945℃ for 100 minutes. After heating and holding, the L-shaped billet is placed on a die and pressed at a speed of 4 mm / s until the forging is flush with the die. The final forging temperature is ≤800℃ to obtain the L-shaped forging.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A forging method for an "L"-shaped large thin plate forging, characterized in that, The "L"-shaped large thin plate forging has an overall length of A, a width of B, and a thickness of C; where 60mm≤C≤90mm, 20C≤A≤30C, 4C≤B≤6C, and the "L"-shaped corner is 90°. The method includes: Step 1: Heat the bar stock to the deformation temperature and forge it into a rectangular first blank with length, width and thickness a, b and c respectively, and a=(0.5~0.7)A, b=(0.7~0.9)B, c=(1.8~2.2)C; Step 2: Set two material sections with a length of d at both ends of the first blank length a, where d = (1 / 7 to 1 / 8)a. Press the two material sections thin to a height of (4 / 5 to 9 / 10)c to obtain the second blank. Step 3: After heating the second blank to the deformation temperature, place the a×c surface flat on a 90° V-shaped fixture, with the length a spanning across the V-shaped fixture, and the center of the a direction aligned with the lowest point of the V-shaped fixture. Place a semi-circular pad at the center of the second blank and press the semi-circular pad to bend the second blank. During the pressing process, the semi-circular pad moves within a range of (1 / 3 to 2 / 3)a on the second blank. The bending process is divided into three stages, using semi-circular pads of different radii for the first, second, and third stages. In the first stage, the first semi-circular pad is used to bend the second blank to an angle of 140-150°. In the second stage, the second semi-circular pad is used to bend the second blank to an angle of 110-120°. In the third stage, the third semi-circular pad is used to bend the second blank to an angle of 90° to obtain the third blank. Step 4: Use a fan-shaped steel plate to thin the protruding part of the corner of the third blank until the height is (4 / 5 to 9 / 10)c to obtain an L-shaped blank; Step 5: Compare the L-shaped blank with the L-shaped template. If the template can cover the L-shaped blank and the distance between the outline of the L-shaped blank and the outline of the template is ≤10mm, the L-shaped blank is qualified. Otherwise, the L-shaped blank should be shaped until it is qualified. Step 6: After heating the L-shaped billet to the deformation temperature, place it in an L-shaped die and press it to obtain an L-shaped forging; the die forging is divided into two heats: local pressing is adopted, the first heat is pressed to a height of (1.2~1.6)C, and the second heat is pressed until the forging fills the cavity.

2. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, Step one also includes: b≤2c.

3. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, In step six, the L-shaped mold is designed based on the dimensions of the L-shaped forging. The width of the L-shaped mold cavity is (1 + material thermal shrinkage rate) × B, the depth is (1 + material thermal shrinkage rate) × C, the outer contour length is (1 + material thermal shrinkage rate) × A, the draft angle is 5°, the edge chamfer is R10, and the L-shaped mold is an open mold.

4. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, In step three, the V-shaped fixture is used to machine a 90° V-shaped groove on the block base, with a V-shaped cross-section length of (0.4~0.5)A, a height of (0.2~0.3)A, and a groove depth of (0.15~0.2)A.

5. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, In step three, the semi-circular pad is a pad with a semi-circular cross-section and a length of L, where L = (3~5)C; and the radius of the third semi-circular pad is equal to the radius of the inner corner of the L-shaped blank bend, the radius of the second semi-circular pad is 4 / 5 of the radius of the third semi-circular pad, and the radius of the first semi-circular pad is 3 / 5 of the radius of the third semi-circular pad.

6. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, In step four, the thickness of the sector-shaped steel plate is 10mm, the central angle of the sector is 65°, and the horizontal projection completely coincides with the horizontal projection at the corner of the L-shaped billet.

7. The forging method for the "L"-shaped large thin plate forging according to claim 1, characterized in that, In step five, the L-shaped template is made of a 3mm thick steel plate. Its horizontal projected area is smaller than that of the L-shaped forging, and its edge is 15-25mm away from the edge of the L-shaped forging. Several holes with a diameter of 2 / 3 of the template width are machined on it, and the distance between the holes is 1 / 3R.

8. The forging method for the "L"-shaped large thin plate forging according to claim 3, characterized in that, The L-shaped mold has one open end along its length.

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