A method for integrally forming a titanium alloy large flange deep drawing part

Abstract

The present invention discloses an integral forming method for a titanium alloy large flange deep drawing part, which mainly includes three processes: preforming, forming and shape correction. The hot forming temperature is above 690°C. The first process adopts a large blanking gap and gathers materials for preforming at 710°C. The second process adopts a small blanking gap and forms part features at 860°C. The third process adopts constant force strong pressing, with a pressure of more than 30t and a temperature of 860°C to flatten wrinkles. The method realizes forming in one mold, saves time and cost, is simple to operate, and the formed parts meet the requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of aerospace sheet metal parts manufacturing, and specifically relates to an integral forming method for a titanium alloy large flange deep drawing part. Background Art

[0002] With the continuous advancement of lightweight aerospace parts, titanium alloy products account for a growing proportion of them. Large flange deep drawing parts are difficult to form at one time or through a set of dies, especially titanium alloy large flange parts, which need to be formed under high temperature. Therefore, such parts are usually formed by welding, which increases costs and cycles. How to efficiently form titanium alloy large flange parts as a whole through a set of dies has become a major problem that must be faced and solved.

[0003] The Chinese invention patent with publication number CN117300026A discloses a die forging method for titanium alloy deep cylinders with flanges, which performs 2 to 6 step-by-step forming on the cylindrical blank to close one end of the cylindrical blank, thereby completing the processing of titanium alloy deep cylinders with flanges. The die forging method uses an integrated forming method to close the end, and the flange and the cylinder are an integral whole, which is suitable for use in high-pressure, high-fatigue, and harsh use environments. Aerospace shells, pressure vessels, etc.; multi-step forming is used, and defects are not easy to occur in the forging process, and the forging yield rate is high; the upper and lower mold structures are simple. The invention uses 4 deformations, and the deformation angle of each deformation is difficult to accurately grasp.

[0004] For titanium alloy large flange drawn parts, the flange is difficult to flow during drawing due to the characteristics of the parts themselves, which will cause cracking of the product during the forming process. Currently, multiple parts are formed separately and then welded together. This solution requires multiple sets of molds, multiple forming and welding, which greatly increases the production cost and cycle. Due to the presence of welds, the product precision and mechanical properties are reduced. Summary of the invention

[0005] In order to solve the above problems, the present invention aims to provide a method for integrally forming a titanium alloy large flange deep drawing part.

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for integrally forming a titanium alloy large flange deep drawing part, mainly including three processes of preforming, forming and correction, the hot forming temperature is above 690°C,

[0007] The first sequence uses a large blanking gap and preforms the aggregate at 710°C;

[0008] The second sequence uses a small blank holder gap and forms the part features at 860°C;

[0009] The third sequence uses constant force pressing, with a pressure of more than 30 tons and a temperature of 860℃ to form and level the folds;

[0010] The three processes are completed on a forming mold. The forming mold includes a die, a pressure edge and a punch from top to bottom. A guide seat, a pressure block and a sheet metal locating pin are arranged on the pressure edge. Guide plates are also arranged on the sides of the pressure edge and the punch. A push rod is connected under the punch.

[0011] Further, the preforming comprises the following steps,

[0012] Step 1: Place the pressure block in the pressure groove corresponding to the pressure edge;

[0013] Step 2: The mold is heated to 700°C ± 10°C in an isothermal hot forming device;

[0014] Step 3: The edge holder is raised to exceed the punch, the sheet is placed on the edge holder, and the sheet is positioned with a sheet positioning pin, and the sheet is preheated to 700℃±10℃;

[0015] Step 4: The die moves downward and closes with the edge press, and the die is pressed downward until it reaches the limit position to complete the forming action.

[0016] Furthermore, the edge pressing gap in step 1 is 1.5 mm ± 0.03 mm.

[0017] Further, the forming part feature comprises the following steps,

[0018] Step 1: Replace the pressure block and place it in the pressure groove corresponding to the pressure edge;

[0019] Step 2: The mold is heated to 850°C ± 10°C in an isothermal hot forming device;

[0020] Step 3: The edge holder is raised to exceed the punch, the preformed part is placed on the edge holder and positioned against the molding surface, and the part is preheated to 850℃±10℃;

[0021] Step 4: The die moves downward and closes with the edge press, and the die is pressed downward until it reaches the limit position to complete the forming action.

[0022] Furthermore, the edge pressing gap in step 1 is 1.25 mm ± 0.03 mm.

[0023] Furthermore, the calibration comprises the following steps:

[0024] Step 1: Remove the pressure block and fully apply the correction force to the parts;

[0025] Step 2: The mold is heated to 850°C ± 10°C in an isothermal hot forming device;

[0026] Step 3: The edge holder is raised to exceed the punch, the part is placed on the edge holder, positioned against the molding surface, and the part is preheated to 850℃±10℃;

[0027] Step 4: The die moves downward and closes with the edge press, and the die is pressed downward until it reaches the limit position to complete the forming action.

[0028] Furthermore, a cutting process hole process is provided between preforming and forming, and a cutting process supplement process is provided between forming and correction, so as to retain the part profile.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] 1. The large edge pressing gap and low temperature forming are adopted to facilitate the flange flow during the forming process and play a role in gathering materials.

[0031] 2. Use small edge gap and high temperature forming to increase the elongation of the material and avoid forming cracks.

[0032] 3. Use constant force pressure and high temperature forming to press and correct the flange to ensure the forming quality and forming accuracy of the parts.

[0033] 4. Molding is achieved in one mold, saving time and cost and easy operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a three-dimensional schematic diagram of the titanium alloy large flange in the present invention;

[0036] Figure 2 It is a schematic plan view of the titanium alloy large flange in the present invention;

[0037] Figure 3 for Figure 2 AA section view;

[0038] Figure 4 It is a schematic diagram of the processing process of the titanium alloy large flange in the present invention;

[0039] Figure 5 It is a schematic diagram of the forming mold in the present invention;

[0040] Figure 6 It is a cross-sectional view of the forming die in the present invention;

[0041] Figure 7A top view of the forming mold in the present invention;

[0042] In the figure, 1-die; 2-edge pressure; 3-punch; 4-guide seat; 5-pressure block; 6-sheet positioning pin; 7-guide plate; 8-thrust rod. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0044] A method for integrally forming a titanium alloy large flange deep drawing part mainly includes three processes: preforming, forming and shape correction.

[0045] The pre-forming process uses a large edge gap and low-temperature forming to facilitate flange flow during the forming process and play a role in gathering materials;

[0046] The forming process uses a small blanking gap and high temperature forming. Raising the temperature increases the elongation of the material and avoids forming cracks.

[0047] The shaping process uses constant force pressure and high temperature forming to perform strong pressure shaping on the flange to ensure the forming quality and forming accuracy of the parts.

[0048] Reference Figure 1-Figure 3 This part is a typical titanium alloy large flange drawn part. The selected flange is wide, the flange has a large curvature, and the flange shape is different from the drawn shape, making it more difficult to form as a whole.

[0049] For titanium alloy materials, the hot forming process has a certain forming temperature range. Within the temperature range, the lower the temperature, the more conducive to the flow of the material; the higher the temperature, the higher the forming limit of the material, and the better the correction effect. The present invention utilizes this characteristic of titanium alloy materials, realizes the material aggregation during the deep drawing process through low temperature, and then forms the part characteristics through high temperature, and finally ensures the quality of the part by shaping. The hot forming temperature of titanium alloy materials is selected to be above 690℃.

[0050] Material: TA15

[0051] Material thickness: 1.2mm

[0052] Product related dimensions: length 190mm, width 133mm, height 35mm, flange arc radius: 453.5mm, middle drawing part: length 150mm, width 80mm, arc radius at both ends 40mm.

[0053] Product profile: 0.3mm

[0054] Forming process route such as Figure 4 Shown

[0055] Forming mold such as Figure 5-Figure 7 As shown, the mold is made of stainless steel 310s.

[0056] The forming process is as follows

[0057] OP10 Cutting

[0058] Cutting Figure 4 (a) The blank shown.

[0059] OP20 Preform

[0060] (1) Place the pressure block 5 in the pressure groove corresponding to the pressure edge 2, ensuring that the pressure edge gap is 1.5 mm;

[0061] (2) The mold is heated to 700°C in an isothermal hot forming device;

[0062] (3) The equipment push rod 8 drives the edge holder 2 to rise above the punch 3;

[0063] (4) Place the blank on the tooling edge 2 and position the blank with the sheet positioning pin 6;

[0064] (5) Preheat the blank to 700°C;

[0065] (6) The die 1 moves downward and closes the die with the edge holder 2;

[0066] (7) Set the equipment push rod 8 to give a blank holding force of 30t and maintain the pressure;

[0067] (8) The die 1 and the edge holder 2 are pressed down to the limit position to complete the forming action;

[0068] (9) Open the mold, take out the parts and cool them down. Figure 4 (b) shown.

[0069] OP30 cutting process holes

[0070] After the pre-forming process, the deformation tendency of deep drawing is changed by opening the process hole; after the process hole is opened, the forming process changes from deep drawing (mainly flange flow) to flanging (mainly process hole flow); the opening hole is as follows Figure 4 (c) shown.

[0071] OP40 Forming

[0072] (1) Replace the pressure block with a smaller height to ensure that the pressure edge clearance is about 1.25 mm;

[0073] (2) The mold is heated to about 850°C in an isothermal hot forming device;

[0074] (3) The equipment push rod 8 drives the edge holder 2 to rise above the punch 3;

[0075] (4) Place the preformed part on the edge holder 2 and position it against the molding surface;

[0076] (5) Preheat the parts to about 850°C;

[0077] (6) The die 1 moves downward and closes the die with the edge holder 2;

[0078] (7) Set the equipment push rod 8 to give a blank holding force of 30t and maintain the pressure;

[0079] (8) The die 1 and the edge holder 2 are pressed down to the limit position to complete the forming action;

[0080] (9) Open the mold, take out the parts and cool them down; Figure 4 (d) as shown.

[0081] OP50 cutting process supplement

[0082] After the pre-forming process and the forming process, the inside of the part cavity has been formed in place, but the wrinkles on the part flange caused by the pre-forming process still have slight wrinkle marks after the forming process; therefore, the cutting process is designed to add a surface to retain the part surface (leave a 5mm margin) so that the correction force acts entirely on the part surface; Figure 4 (e) shown.

[0083] OP60 calibration

[0084] (1) Remove the pressure block 5, and the correction force acts completely on the parts;

[0085] (2) The mold is heated to about 850°C in an isothermal hot forming device;

[0086] (3) The equipment push rod 8 drives the edge holder 2 to rise above the punch 3;

[0087] (4) Place the part on the edge holder 2 and position it against the profile;

[0088] (5) Preheat the sheet to about 850°C;

[0089] (6) The die 1 moves downward and closes the die with the edge holder 2;

[0090] (7) Set the equipment push rod to give a blank holding force of 30t and maintain the pressure;

[0091] (8) The die 1 and the edge holder 2 are pressed down to the limit position to complete the forming action;

[0092] (9) Open the mold, take out the parts and cool them down; Figure 4 (f) shown.

[0093] OP70 Cut

[0094] Cutting part shape, parts such as Figure 4 (g) shown.

[0095] The above is a detailed introduction to the integral forming method of a titanium alloy large flange deep drawing part provided by the present invention. This article uses specific examples to illustrate the structure and working principle of the present invention. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in several ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for integrally forming a titanium alloy large flange deep drawing part, characterized in that: It mainly includes three processes: preforming, forming and calibration. The hot forming temperature is above 690℃. The first sequence uses a large blanking gap and preforms the aggregate at 710°C; The second sequence uses a small blank holder gap and forms the part features at 860°C; The third sequence uses constant force pressing, with a pressure of more than 30t and a temperature of 860℃ to level the wrinkles; The first-order large blanking clearance is 1.5mm±0.03mm, and the second-order small blanking clearance is 1.25mm±0.03mm; The three steps are completed on a forming mold, which comprises a die (1), a pressure edge (2) and a punch (3) from top to bottom. A guide seat (4), a pressure block (5) and a sheet metal positioning pin (6) are arranged on the pressure edge (2). Guide plates (7) are also arranged on the sides of the pressure edge (2) and the punch (3). A push rod (8) is connected below the punch (3). The pressure block (5) is removably arranged in a pressure groove corresponding to the pressure edge (2).

2. The integral forming method of the titanium alloy large flange deep drawing part according to claim 1 is characterized in that: The preforming comprises the following steps, Step 1: placing the pressure block (5) in the pressure groove corresponding to the pressure edge (2); Step 2: The mold is heated to 700°C ± 10°C in an isothermal hot forming device; Step 3: The edge holder (2) is raised to exceed the punch (3), the sheet is placed on the edge holder (2), and the sheet is positioned using the sheet positioning pin (6), and the sheet is preheated to 700°C ± 10°C; Step 4: The die (1) moves downward and closes with the edge holder (2), and the die is pressed downward until it reaches the limit position, completing the forming operation.

3. The integral forming method of the titanium alloy large flange deep drawing part according to claim 1 is characterized in that: The formed part features The following steps are included: Step 1: Replace the pressure block (5) and place the pressure block (5) in the pressure groove corresponding to the pressure edge (2); Step 2: The mold is heated to 850°C ± 10°C in an isothermal hot forming device; Step 3: The edge holder (2) is raised to exceed the punch (3), the preformed part is placed on the edge holder (2) and positioned against the molding surface, and the part is preheated to 850°C ± 10°C; Step 4: The die (1) moves downward and closes with the edge holder (2), and the die is pressed downward until it reaches the limit position, completing the forming operation.

4. The integral forming method of the titanium alloy large flange deep drawing part according to claim 1 is characterized in that: The calibration comprises the following steps: Step 1: Remove the pressure block (5) so that the correction force acts completely on the part; Step 2: The mold is heated to 850°C ± 10°C in an isothermal hot forming device; Step 3: The edge holder (2) is raised to exceed the punch (3), the part is placed on the edge holder (2), positioned against the molding surface, and the part is preheated to 850℃±10℃; Step 4: The die (1) moves downward and closes with the edge holder (2), and the die is pressed downward until it reaches the limit position, completing the forming operation.

5. The integral forming method of the titanium alloy large flange deep drawing part according to claim 1 is characterized in that: A cutting process hole process is arranged between preforming and forming, and a cutting process supplement process is arranged between forming and correction to retain the part profile.

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