Large titanium alloy double-hole frame forge piece forming process method

Abstract

The invention provides a large titanium alloy double-hole frame forge piece forming process method which comprises the steps that a heated round bar is placed in a combined type pre-forming die to be pressed to a designated position, and a blank with a certain shape is obtained; the combined type pre-forming die comprises an upper die, a lower die and a die core with a certain shape. The obtained blank is taken out, remelted and heated and then put into a pre-forging die to be pre-formed, and a pre-forged piece is obtained through pre-forging deformation; the pre-forging die consists of an upper die and a lower die; and finally, the pre-forged blank is put into a final forging die to be subjected to final forging forming after being remelted and heated, and a final forging piece is obtained. By the adoption of the method, the complex free forging blank manufacturing process is avoided, the round bar is directly put into the blank manufacturing die to be deformed, the production quality and efficiency of forgings are guaranteed, forming on a fifty thousand-ton press can be achieved, the forming load is greatly reduced, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention relates to a forming process for a large titanium alloy double-hole frame forging and a design method for a combined preforming die, belonging to the field of titanium alloy plastic forming. Background Art

[0002] In the aviation industry, titanium alloy double-hole frames serve as the main load-bearing components of aircraft, and their forming quality is crucial to aircraft flight safety. However, their complex shape and large projected area pose numerous challenges during the forging production process. On the one hand, defects such as underfilling and folding are very likely to occur, seriously affecting the quality and performance of the forgings. On the other hand, traditional titanium alloy double-hole frame forgings are mostly formed by sheet metal die forging, and the quality of free forging has a significant impact on its forming quality. Furthermore, there are numerous process steps, which not only leads to low production efficiency but also extremely high forming loads, placing extremely high demands on both equipment and processes.

[0003] With the continuous development of the aviation industry, the demand for large titanium alloy double-hole frames is increasing, and the limitations of traditional processes are becoming more and more obvious. There is an urgent need for innovative forming processes and molds to solve these problems in order to meet the aviation manufacturing needs for high-quality and high-efficiency forgings. Summary of the Invention

[0004] In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a large titanium alloy double-hole frame forging forming process method to solve the problems of the prior art such as low production efficiency, high cost, dependence of the quality of free forging billets on the workers' operating experience, and inability to ensure stability and consistency during forging production.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: A forming process for a large titanium alloy double-hole frame forging comprises the following steps: Step 1: Place the heated round bar material into a combined preforming die and press it to a specified position to obtain a blank with a certain shape; the combined preforming die includes an upper die, a lower die and a die core with a certain shape; Step 2: taking out the blank obtained in step 1, returning it to the furnace for heating, and then placing it in a pre-forging die for pre-forging deformation to obtain a pre-forged part; the pre-forging die is composed of an upper die and a lower die; Step 3: After the pre-forged billet is returned to the furnace for heating, it is placed in the final forging die for final forging to obtain the final forging.

[0006] Furthermore, a groove for accommodating the die core is provided in the lower die, and the groove corresponds to the shape of the lower part of the pre-forging.

[0007] Furthermore, after the pre-forming in step 2 is completed, the core of the pre-forming lower die is ejected by the lower die push rod, and the pre-forming lower die after the core is taken out serves as the pre-forging lower die, and the pre-forging upper die remains the pre-forming upper die; after the core in the pre-forging lower die is taken out, an inner flash bin is formed at the core position to accommodate excess metal during the pre-forging process.

[0008] Furthermore, in the pre-forging process of step 2, the deformation times are adjusted according to the deformation amount.

[0009] Furthermore, after the pre-forging in step 2, the billet is directly heated and placed in the final forging die for final forging deformation. After the final forging is completed, the flash of the billet is cut off, and then the billet is returned to the furnace for heating and final forging deformation. The press presses the upper and lower dies to the specified position; and the number of deformation fires can be adjusted according to the deformation amount during the final forging process.

[0010] Furthermore, the structure of the mold core consists of two upper and lower bosses based on the parting surface, and the total thickness of the mold core is h1+h2, of which the thickness of the boss higher than the parting surface is h1, and the installation depth of the mold core in the pre-forging mold based on the parting surface is h2; an arc groove with a depth of h3 is set on the upper surface of the mold core and the prefabricated upper mold for positioning the round bar material, and dividing platforms with lengths of L1 and L2 are set on the left and right of the arc groove. The outer side of the dividing platform is designed to have a slope transition angle of θ1, and the far end side of the frame changes its slope to θ2 at an equal distance from the proximal end to coordinate the material flow; the radius of the lower surface of the mold core and the preforming mold are R1, and the radius of the preforming lower mold and the core are R2, and the press presses the upper and lower molds to the specified position.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention proposes a completely new process route: round bar stock → blanking → pre-forging → final forging. Traditional large double-hole frame forging processes typically involve free forging round bar stock into blanks, followed by die forging. This process presents challenges such as numerous free forging steps, the quality of free forging being easily affected by operator manipulation, and unstable quality in actual production. This invention eliminates these numerous cumbersome free forging steps and, by optimizing the forming steps, enables the forming of large double-hole frames on a 50,000-ton press, significantly improving production efficiency and process stability.

[0012] 2. The method of the present invention provides a mold core in the blank making lower mold. After the blank making is completed, the mold core is taken out and can be directly used as a pre-forging lower mold. This design not only simplifies the mold structure and production process, but also the mold core can directly form the round bar material into a blank with a double-hole frame shape while reducing the forming load, saving mold materials and reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the prefabricated mold of the present invention; Figure 2This is a cross-sectional view of the prefabricated mold of the present invention taken along line AA; Figure 3 This is a front view of the prefabricated mold core structure of the present invention; Figure 4 This is a front view of the lower mold cavity of the pre-forging die of the present invention.

[0014] In the figure, 1 is the upper die, 2 is the lower die, 3 is the core, 4 is the round bar material, 5 is the groove, and 6 is the ejector hole. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings.

[0016] Example 1 See also Figure 1 and Figure 2 The present invention provides a large titanium alloy double-hole frame forging forming process method, which is used to process a large titanium alloy double-hole frame for a certain aviation, and specifically includes the following steps: Step 1: Place the heated round bar material 4 into a combined preforming die and press it to a specified position to obtain a blank with a certain shape; the combined preforming die includes an upper die 1, a lower die 2, and a core 3 with a certain shape; the lower die 2 is provided with a groove 5 for accommodating the core and corresponding to the shape of the preforging; Step 2: taking out the blank obtained in step 1, returning it to the furnace for heating, and then placing it in a pre-forging die for pre-forming, and obtaining a pre-forged part through pre-forging deformation; the pre-forging die is composed of an upper die 1 and a lower die 2; Step 3: After the pre-forged billet is returned to the furnace for heating, it is placed in the final forging die for final forging to obtain the final forging.

[0017] In this embodiment, the frame forging material is TA15 titanium alloy, and the round bar material size is selected to be φ350×3000 mm. Ultimately, the round bar material is deformed into a forging that meets the size requirements of the drawing.

[0018] See also Figure 3 and Figure 4The thickness (H) of the core 3 (h1 + h2) is 80-120mm, the thickness of the boss above the parting surface (h1) is 40-60mm, and the installation depth (h2) of the core 3 in the pre-forging die is 60-80mm. A circular arc groove with a depth (h3) of 10-20mm is provided on the upper surface of the core 3 and the prefabricated upper die for positioning the round bar. Material distribution platforms with lengths (L1) of 100-150mm and (L2) of 30-50mm are provided on the left and right sides of the core groove, respectively. The outer sides of the distribution platforms are designed with a slope transition angle (θ1) of 3°-5°. The slope (θ2) of the distal end of the frame changes to 5°-7° at an equal distance from the proximal end to coordinate material flow. The radius (R1) of the lower surface of the core 3 where it meets the blanking die (lower die) 2 is 3-5mm, and the radius (R2) of the prefabricated lower die 2 where it meets the core 3 is 10-15mm.

[0019] During the blank deformation, the mold is heated to 300-350℃, the blank is heated to 950-965℃ and kept warm, then taken out of the furnace, covered and returned to the furnace for insulation. After the temperature of the blank is evenly distributed, it is transferred to the press for blank deformation. According to the deformation amount, the preforming is divided into two fires. After the first fire is completed, the blank is returned to the furnace for heating and then the second fire is carried out. After the blank is completed, the core 3 in the prefabricated lower die 2 is ejected by the ejector pin through the lower die ejector pin hole 6. At this time, the prefabricated lower die after taking out the core 3 is used as the pre-forging lower die, and the prefabricated upper die is used as the pre-forging upper die for pre-forging deformation. The blank is returned to the furnace for heating to 950-965℃, taken out of the furnace, covered and returned to the furnace for insulation, and then transferred to the pre-forging die for pre-forging deformation. According to the deformation amount, the pre-forging deformation is divided into three fires. After the pre-forging is completed, the blank is returned to the furnace for heating to 950-965℃, covered and then transferred to the final forging die for final forging deformation. The final forging process is divided into two fires according to the deformation amount. The deformation process is carried out on a 50,000-ton press. The size, shape and performance of the forging products obtained by the above scheme all meet the requirements of the drawings.

[0020] By comparison, the processing of large-scale aviation titanium alloy double-hole frames of the same specifications requires forming on an 80,000-ton press using traditional sheet metal forming methods; while the method of the present invention can be used on a 50,000-ton press, which greatly reduces the forming load and processing costs. In addition, the traditional forming method requires a complex and lengthy free forging process, which has low production efficiency, and the quality of free forgings is dependent on the workers' operating experience, and cannot guarantee the stability and consistency of forgings during production; the method of the present invention circumvents the complex free forging process and directly places the round bar material into the blanking die for deformation, thereby ensuring the quality and efficiency of forging production. At the same time, this forming method combines the blanking die and the pre-forging die into one by providing a combined die structure with a detachable core in the pre-forging die, which can save a set of blanking dies in production, save production costs and achieve the purpose of reducing costs and increasing efficiency. The process method of the present invention is not limited to large titanium alloy forgings, nor is it limited to forgings of the structural shape described in this embodiment, but is suitable for the forming of large whole frame forgings.

[0021] In summary, the process route of the present invention is to directly place the round bar material into the pre-forming die for blanking deformation, and then perform pre-forging and final forging. Compared with the traditional forging process of large titanium alloy double-hole frames, it saves a lot of free forging processes, improves the production efficiency of forgings and the stability and consistency of forgings during production. This process realizes the forming of large double-hole frames on a 50,000-ton press. In addition, the combined mold structure of the present invention is that a mold core is provided in the pre-forming lower mold, and the mold core is taken out after the blanking is completed, which is the pre-forging lower mold. The design of the mold core can directly form the round bar material into a blank with a double-hole frame shape while reducing the forming load, avoiding the influence of the operating factors of the free forging workers on the quality of the forgings, while shortening the production cycle and improving production efficiency.

[0022] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention 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 make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A large titanium alloy double-hole frame forging forming process, characterized in that: The following steps are involved: Step 1: Place the heated round bar material into a combined preforming die and press it to a specified position to obtain a blank with a certain shape; the combined preforming die includes an upper die, a lower die and a die core with a certain shape; Step 2: taking out the blank obtained in step 1, returning it to the furnace for heating, and then placing it in a pre-forging die for pre-forging, and obtaining a pre-forged part through pre-forging deformation; the pre-forging die is composed of an upper die and a lower die; Step 3: After the pre-forged billet is returned to the furnace for heating, it is placed in the final forging die for final forging to obtain the final forging.

2. The titanium alloy double-hole frame forging forming process according to claim 1, characterized in that: The lower die is provided with a groove for accommodating the die core, and the groove corresponds to the shape of the lower part of the pre-forging.

3. The titanium alloy double-hole frame forging forming process according to claim 1, characterized in that: After the preforming is completed in step 2, the core of the preforming lower die is ejected by the lower die ejector pin, and the preforming lower die after the core is taken out serves as the pre-forging lower die, and the pre-forging upper die remains the pre-forming upper die; after the core in the pre-forging lower die is taken out, an inner flash bin is formed at the core position to accommodate excess metal during the pre-forging process.

4. The titanium alloy double-hole frame forging forming process according to claim 1, characterized in that: In the pre-forging process of step 2, the deformation times are adjusted according to the deformation amount.

5. The titanium alloy double-hole frame forging forming process according to claim 1, characterized in that: After the pre-forging in step 2, the billet is directly heated and placed in the final forging die for final forging deformation. After the final forging is completed, the flash of the billet is cut off, and then the billet is returned to the furnace for heating and final forging deformation. The press presses the upper and lower dies to the specified position. In addition, the number of deformation fires can be adjusted according to the deformation amount during the final forging process.

6. The titanium alloy double-hole frame forging forming process according to claim 1, characterized in that: The structure of the mold core consists of two upper and lower bosses based on the parting surface. The total thickness of the mold core is h1+h2, of which the thickness of the boss higher than the parting surface is h1, and the installation depth of the mold core in the pre-forging mold based on the parting surface is h2; an arc groove with a depth of h3 is set on the upper surface of the mold core and the prefabricated upper mold for positioning the round bar material, and dividing platforms with lengths of L1 and L2 are set on the left and right of the arc groove. The outer side of the dividing platform is designed to have a slope transition angle of θ1, and the far end side of the frame changes its slope to θ2 at an equal distance from the proximal end to coordinate the material flow; the fillet of the lower surface of the mold core and the preforming mold is R1, and the fillet of the preforming lower mold and the mold core is R2.

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