Forming method of titanium alloy die forging with boss and circular arc frame

Abstract

This invention belongs to the field of material hot working, specifically relating to a forming method for a titanium alloy die forging with a bossed arc frame. The method includes: flattening a bar stock cut to specifications along its length onto a slab using a free forging hammer; then pressing and shaping one end of the slab longitudinally to a specified size; heating the slab in an electric furnace, then placing it upright into a dedicated forging blank die, eccentrically pressing the portion exposed outside the die, causing the eccentrically pressed portion of the bar stock to flow laterally to form a boss, thus obtaining a first intermediate blank; elongating the first intermediate blank, placing one end into the dedicated forging blank die to a specified size, and shaping it as a whole to obtain a second intermediate blank; and gradually pressing and bending the thin rod of the second intermediate blank using an anvil to obtain a rough shape of a sickle frame similar in shape and volume to the final forging.

Description

Technical Field

[0001] This invention belongs to the field of material hot working, and specifically relates to a forming method for a titanium alloy die forging with a bossed arc frame. Background Technology

[0002] The aerospace industry is experiencing a growing demand for high-performance and lightweight structures. Large, curved integral frame forgings play a crucial role in connecting and supporting structures within aircraft fuselages, providing sufficient strength and stiffness to withstand various forces and vibrations during flight. Furthermore, large, curved integral frame forgings reduce connection points and weld joints, thereby improving the overall reliability and safety of the structure.

[0003] However, existing technology cannot form large arc-shaped integral frame forgings as a whole. It is necessary to splice the boss part and the arc segment part. The connection point and welded joint pose safety hazards during the use of the forging. Summary of the Invention

[0004] Purpose of the invention: To provide a forming method for titanium alloy die forgings with a bossed arc frame, which solves the problems of multiple forging passes and poor shape quality in existing forging methods. The forging process is simple and meets the process requirements.

[0005] Technical solution

[0006] This invention provides a method for forming a titanium alloy forging with a bossed arc frame, comprising:

[0007] The bars cut to specifications are flattened along the length of the free forging hammer into a slab, and then one end of the slab in the longitudinal direction is pressed and shaped to the specified size.

[0008] After the slab is heated in an electric furnace, it is stood up and placed in a special forging blank die. The part exposed outside the special forging blank die is eccentrically pressed, so that the part of the bar material that is eccentrically pressed flows laterally to form a boss, thus obtaining the first intermediate billet.

[0009] The first intermediate billet is drawn out and placed into one end of a special forging blank die to a specified size and shaped as a whole to obtain the second intermediate billet;

[0010] The second intermediate billet is gradually pressed and bent using an anvil to obtain a rough shape of a sickle frame that is similar in shape and volume to the final forging.

[0011] Furthermore, the method also includes:

[0012] The rough shape is placed into the cavity of the final forging mold to form the final titanium alloy forging with a boss and an arc frame.

[0013] The final forging is placed in an electric furnace and heated to 850±10℃ for 150±15 minutes. After being removed from the furnace, it is air-cooled to room temperature.

[0014] Furthermore, the flattening and shaping process requires three heating cycles. The first two heating cycles press the bar stock into a slab, and the third heating cycle forges it to the specified shape and size.

[0015] Furthermore, the first intermediate billet is forged into a die through two firings.

[0016] Further, the first intermediate billet is drawn out and placed into one end of a special forging die to a specified size and shaped as a whole to obtain the second intermediate billet, including:

[0017] The first intermediate billet is drawn out on a 2500t high-speed forging mill, and the drawn end is widened.

[0018] The second intermediate blank is bent into a rough shape using a V-shaped anvil.

[0019] Furthermore, the final forging is carried out in multiple stages of pressing, with the deformation amount controlled between 5% and 25% per stage; the forging temperature is 30-50℃ below the phase transformation point.

[0020] Furthermore, the preheating temperature of the tooling and equipment is 200℃-300℃.

[0021] Furthermore, the special forging blank mold is a square module with one side extending upwards to the backrest; the square module has a cavity opened to the bottom next to the backrest, the cavity is used to stand the bar stock upright to prevent it from sticking to the backrest.

[0022] Beneficial effects:

[0023] The forming of large integral titanium alloy forgings with bossed arc frames effectively solves the forming method of such complex-shaped frame forgings. In this forming method, the use of special molds and V-shaped hammer anvil bending greatly improves the material utilization rate of the forgings. The integral forming of the forgings improves the comprehensive performance of the forgings, thereby improving the reliability and safety of the overall structure. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the undeveloped terrain.

[0025] Figure 2 This is a schematic diagram of the first intermediate blank before it enters the mold.

[0026] Figure 3 This is a schematic diagram of material placement in the mold. Detailed Implementation

[0027] 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.

[0028] This invention provides a method for forming a titanium alloy forging with a bossed arc frame, comprising:

[0029] The bars cut to specifications are flattened along the length of the free forging hammer into a slab, and then one end of the slab in the longitudinal direction is pressed and shaped to the specified size.

[0030] After the slab is heated in an electric furnace, it is stood up and placed in a special forging blank die. The part exposed outside the special forging blank die is eccentrically pressed, so that the part of the bar material that is eccentrically pressed flows laterally to form a boss, thus obtaining the first intermediate billet.

[0031] The first intermediate billet is drawn out and placed into one end of a special forging blank die to a specified size and shaped as a whole to obtain the second intermediate billet;

[0032] The second intermediate billet is gradually pressed and bent using an anvil to obtain a rough shape of a sickle frame that is similar in shape and volume to the final forging.

[0033] Furthermore, the method also includes:

[0034] The rough shape is placed into the cavity of the final forging mold to form the final titanium alloy forging with a boss and an arc frame.

[0035] The final forging is placed in an electric furnace and heated to 850±10℃ for 150±15 minutes. After being removed from the furnace, it is air-cooled to room temperature.

[0036] Furthermore, the flattening and shaping process requires three heating cycles. The first two heating cycles press the bar stock into a slab, and the third heating cycle forges it to the specified shape and size.

[0037] Furthermore, the first intermediate billet is forged into a die through two firings.

[0038] Further, the first intermediate billet is drawn out and placed into one end of a special forging die to a specified size and shaped as a whole to obtain the second intermediate billet, including:

[0039] The first intermediate billet is drawn out on a 2500t high-speed forging mill, and the drawn end is widened.

[0040] The second intermediate blank is bent into a rough shape using a V-shaped anvil.

[0041] Furthermore, the final forging is carried out in multiple stages of pressing, with the deformation amount controlled between 5% and 25% per stage; the forging temperature is 30-50℃ below the phase transformation point.

[0042] Furthermore, the preheating temperature of the tooling and equipment is 200℃-300℃.

[0043] Furthermore, the special forging blank mold is a square module with one side extending upwards to the backrest; the square module has a cavity opened to the bottom next to the backrest, the cavity is used to stand the bar stock upright to prevent it from sticking to the backrest.

[0044] This invention provides a method for forming a titanium alloy forging with a bossed arc frame, comprising:

[0045] Step 1: Determine the shape of the wasteland Figure 1 As shown, the rough shape is a sickle shape composed of a boss section and a circular arc section. The difficulty lies in the large size, complex shape, and large variation in the cross-section of the forging; therefore, a special die is used for die forging.

[0046] The bars cut to specifications are heated to the forging temperature in an electric furnace, flattened into slabs along the length direction on a free forging hammer, and then one end of the slabs is pressed and shaped to the specified size in the longitudinal direction.

[0047] Step Two: After heating the slab in the electric furnace, stand it upright and place it into a special forging die. Figure 3 In this process, the die adopts a backrest design, and eccentric pressing is achieved by vertical pressure from a high-speed forging machine to obtain the first intermediate billet, as shown in the figure. Figure 2 As shown, during production, a special blanking and forging die is used, and the outline of the die cavity is the same as the outline of the blank. The eccentric pressing method is used to achieve material separation, and the blank is pressed into an intermediate blank with a volume similar to that of the die forging. This method is simple to operate, the production process is easy to control, the dimensions of the intermediate blank produced are stable, which greatly improves the consistency of the dimensions of the blank in the same batch, and at the same time improves the material utilization rate.

[0048] Step 3: After heating the first intermediate billet in an electric furnace, one end of the long thin rod is drawn out to the specified size and shaped as a whole to obtain the second intermediate billet. This method cleverly sets up the forging process, placing the step of forging the long thin rod end in the later stage, reducing the difficulty of transferring the whole forging material and the operation of workers.

[0049] Step 4: After heating the second intermediate billet in an electric furnace, use a V-shaped anvil to gradually press and bend the thin rod to obtain a rough shape that is similar to the shape and volume of the final forging;

[0050] Step 5: Final forging. After heating the rough shape in an electric furnace, it is placed into the final forging mold cavity to form the final titanium alloy forging with a bossed arc frame (sickle frame).

[0051] Step 6: Heat treatment. Place the final forging into an electric furnace and heat it at a temperature of 850±10℃ above the phase transformation point. Hold it at that temperature for 150±15 minutes. After removing it from the furnace, let it air cool to room temperature.

[0052] Example 1

[0053] This forging is characterized by its complex shape with a raised, arc-shaped part, and is formed using a die and forging process.

[0054] Forging characteristics: This forging belongs to a frame structure, with a "sickle" shape. The difference in cross-sectional area between the handle and the blade of the "sickle" is large, with a maximum cross-sectional area of ​​99498 mm². 2 The minimum cross-sectional area is only 4300 mm² 2， The ratio is 23:1. The arc length reaches 2845mm, and it is a double-shaped, thin-walled, high-ribbed forging with a projected area of ​​approximately 0.51m². 2 A titanium alloy forging weighing approximately 115 kg. (Transmitted via...) The bar stock is formed through free forging and flattening, die forging, bending forging, and die forging. The forging temperature is 40±10°C below the phase transformation point, and the temperature is held for a certain time. The billet is formed in 9 passes, and the die forging is completed in 3 passes. The deformation amount per pass is 15%-30%. Forgings with good shape, qualified microstructure and properties are obtained.

Claims

1. A method for forming a titanium alloy forging with a bossed arc frame, characterized in that, include: The bars cut to specifications are flattened along the length of the free forging hammer into a slab, and then one end of the slab in the longitudinal direction is pressed and shaped to the specified size. After the slab is heated in an electric furnace, it is stood up and placed in a special forging blank die. The part exposed outside the special forging blank die is eccentrically pressed, so that the part of the bar material that is eccentrically pressed flows laterally to form a boss, thus obtaining the first intermediate billet. The first intermediate billet is drawn out and placed into one end of a special forging blank die to a specified size and shaped as a whole to obtain the second intermediate billet; The thin rod is gradually pressed and bent using an anvil to obtain a rough shape of a sickle frame that is similar in shape and volume to the final forging. The rough shape is placed into the cavity of the final forging mold to form the final titanium alloy forging with a boss and an arc frame. The special forging blank mold is a square module with one side extending upwards to the backrest; the square module has a cavity opened to the bottom next to the backrest, and the cavity is used to hold the bar stock vertically, with the bar stock against the backrest.

2. The method according to claim 1, characterized in that, The method further includes: The final forging is placed in an electric furnace and heated to 850±10℃ for 150±15 minutes. After being removed from the furnace, it is air-cooled to room temperature.

3. The method according to claim 1, characterized in that, Flattening and shaping require three firing processes. The first two firing processes press the bar stock into a slab, and the third firing process forges it into the specified shape and size.

4. The method according to claim 1, characterized in that, The first intermediate billet is forged into a die through two firings.

5. The method according to claim 1, characterized in that, The first intermediate billet is drawn out and placed into one end of a special forging die to a specified size and shaped as a whole to obtain the second intermediate billet, which includes: The first intermediate billet is drawn out on a 2500t high-speed forging mill, and the drawn end is widened.

6. The method according to claim 1, characterized in that, The second intermediate blank is bent into a rough shape using a V-shaped anvil.

7. The method according to claim 2, characterized in that, The final forging is carried out in multiple stages, with the deformation amount controlled between 5% and 25% per stage; the forging temperature is 30-50℃ below the phase transformation point.

8. The method according to claim 2, characterized in that, The preheating temperature of the tooling and equipment is 200℃-300℃.

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