A method for manufacturing a single-sided stepped titanium alloy forging

Abstract

The application relates to a manufacturing method of a single-side stepped titanium alloy forge piece, and belongs to the technical field of metal forging processing. The method can effectively reduce the cost increase caused by excessive coating and excessively large corner collapse, and the method comprises the following steps: determining a blanking specification according to the weight and the maximum cross-sectional area of the forge piece, blanking according to the blanking specification to obtain a bar blank; performing cross-section upsetting of a rectangular blank along the length direction by using an upsetting tool to obtain a trapezoidal blank with a small upper part and a large lower part; placing the trapezoidal blank on a lower anvil to make the bottom surface of the trapezoidal blank adhere to the lower anvil; pressing a material distribution mark on the top surface of the trapezoidal blank by using a stamping and material distribution tool according to the step size, the material distribution mark separates the trapezoidal blank into a main body area and a target area; driving the upper anvil to forge the target area by using a forging equipment to make the target area press down to form a step, thereby obtaining an intermediate blank; and elongating the main body area by using an elongating tool to obtain a free forging forge piece.

Description

Technical Field

[0001] This invention belongs to the field of metal forging technology, and specifically relates to a method for manufacturing a single-sided stepped titanium alloy forging. Background Technology

[0002] Titanium alloys possess unique properties such as high strength, low density, and excellent corrosion resistance, making them widely used in the aerospace industry. To quickly obtain titanium alloy products for testing the rationality of product design and the reliability of performance, titanium alloy parts are often manufactured using free forging.

[0003] Traditional free forging designs are generally based on the envelope of the part's maximum outer contour, resulting in a simple cuboid shape. This approach leads to low material utilization. To improve material utilization, a single-sided step design is often incorporated into the forging, depending on the part's structure. Currently, single-sided stepped forgings, during the forging process, such as... Figure 1 As shown, a square forging blank 1 is typically placed on a lower anvil 2, and then an upper anvil 3 is used to forge a portion of the square forging blank 1's edge (i.e., the area corresponding to the step). During this process, because the bottom surface of the square forging blank 1 is fully in contact with the lower anvil 2, while the upper anvil 3 can only act on a portion of the upper surface of the square forging blank 1, the metal in the area forged by the upper anvil 3 flows outward at a greater speed than the metal at the bottom. Consequently, the edge of the step protrudes outward from the bottom edge of the square forging blank 1, with the protrusion distance defined as ΔS. However, the shortest dimension is usually used to determine whether a part can be machined. Therefore, the square forging blank 1 after the step is machined is judged based on its bottom edge. Thus, the portion of the step edge protruding from the bottom edge will be considered as filler material 4. Although this can be eliminated by cutting during subsequent processing, it will result in material waste and increase the cost of forging.

[0004] In addition, in the existing technology, the upper flat anvil 3 is usually used to directly forge the local edge of the square forging billet 1. Although a step can be forged, due to the rigidity and adhesion of the metal, a large collapse angle 5 will be formed at the part where the upper surface of the square forging billet 1 meets the step during forging with the upper flat anvil 3. Moreover, the collapse angle 5 increases with the increase of the step height. Of course, the collapse angle 5 can be compensated by the forging process. However, the larger the collapse angle 5 is, the more material is required to compensate, which will also increase the cost of forging.

[0005] Current methods for manufacturing single-sided stepped titanium alloy forgings cannot effectively reduce the forging costs caused by the two reasons mentioned above. Therefore, a more reasonable and lower-cost method for manufacturing single-sided stepped titanium alloy forgings is urgently needed. Summary of the Invention

[0006] The application provides a manufacturing method of a single-step titanium alloy forging, and aims at solving the technical problem that the current manufacturing method of the single-step titanium alloy forging cannot effectively reduce the cost increase of the forging caused by excessive coating and excessive corner collapse.

[0007] The application is achieved by the following technical scheme: a manufacturing method of a single-step titanium alloy forging, comprising:

[0008] Step 1: determining the blanking specification according to the weight and the maximum cross-sectional area of the forging, and blanking according to the blanking specification to obtain a bar blank;

[0009] Step 2: elongating the bar blank by using an elongation tool to obtain a rectangular blank;

[0010] Step 3: changing the cross section of the rectangular blank along the length direction of the rectangular blank by using a upsetting tool to obtain a trapezoidal blank with a small upper part and a large lower part;

[0011] Step 4: placing the trapezoidal blank on a lower anvil so that the bottom surface of the trapezoidal blank is attached to the lower anvil;

[0012] Step 5: pressing a distribution mark on the top surface of the trapezoidal blank according to the step size by using a press-in distribution tool, and the distribution mark separates the trapezoidal blank into a main body area and a target area;

[0013] Step 6: driving the upper anvil to forge the target area by using a forging equipment to make the target area form a step by being pressed downward to obtain an intermediate blank;

[0014] Step 7: elongating the main body area by using an elongation tool to obtain a free forging forging.

[0015] Further, in the step 1, the weight of the bar blank is M, and the diameter of the bar blank is D;

[0016] 1.05m≤M≤1.3m, wherein m is the weight of the forging;

[0017] 1.1s≤S≤1.5s, wherein s is the maximum cross-sectional area of the forging, and S=ΠD² / 4.

[0018] Further, in the step 3, the bottom angle of the trapezoidal blank is α, and 3°≤α≤10°;

[0019] The height of the trapezoidal blank is H, and h+20mm≤H≤h+40mm, wherein h is the total height of the forging;

[0020] The horizontal distance of the upper base and the lower base of the trapezoidal blank on the single side is L, and L=ΔS.

[0021] Further, in order to better realize the present application, the bottom angle a of the trapezoidal blank is in positive correlation with the height H of the trapezoidal blank.

[0022] Further, in order to better realize the present application, the depth t of the material distribution mark in step 5 is 20mm≤t≤40mm.

[0023] Further, in order to better realize the present application, the depth t of the material distribution mark is in positive correlation with the height H of the trapezoidal blank.

[0024] Further, in order to better realize the present application, the material distribution pressing tool is a tapered structure with large top and small bottom, and a round corner is arranged at the edge angle between the bottom end face and the side face of the material distribution pressing tool;

[0025] The radius of the round corner is r, and 8mm≤r≤15mm.

[0026] The width of the material distribution pressing tool is W, and 30mm≤W≤60mm.

[0027] The inclination angle of the side face of the material distribution pressing tool is β, and 2°≤β≤3°.

[0028] Further, in order to better realize the present application, in the process of obtaining the intermediate blank in step 6, if the step depth is greater than the depth of the material distribution mark, the target area is forged by the upper anvil for multiple times, and before each forging, the material distribution pressing tool is used to press a mark at the joint between the step and the main body part.

[0029] Further, in order to better realize the present application, the bar blank before drawing, the rectangular blank before upsetting, the trapezoidal blank before material distribution pressing, and the intermediate blank before drawing are heated to 30-70℃ below the phase transition point by using an electric furnace, and the heating time is calculated according to 0.3-1.1min / mm.

[0030] Further, in order to better realize the present application, the drawing tool, the upsetting tool, the upper anvil, the lower anvil, and the material distribution pressing tool are preheated by using a natural gas furnace before use, and the preheating time is not less than 10 hours, so that the temperature of the drawing tool, the upsetting tool, the upper anvil, the lower anvil, and the material distribution pressing tool during use is not less than 200℃.

[0031] Compared with the prior art, the present application has the following beneficial effects:

[0032] The manufacturing method of the single-step titanium alloy forging provided by the application comprises the following steps: determining the blanking specification according to the weight and the maximum cross-sectional area of the forging, blanking according to the blanking specification to obtain a bar blank; using a heading tool to perform cross-section heading on the rectangular blank along the length direction of the rectangular blank to obtain a trapezoidal blank with a small upper part and a large lower part; placing the trapezoidal blank on a lower anvil so that the bottom surface of the trapezoidal blank is attached to the lower anvil; using a stamping and distributing tool to stamp a distribution mark on the top surface of the trapezoidal blank according to the step size, and the distribution mark separates the trapezoidal blank into a main body area and a target area; using a forging equipment to drive an upper anvil to forge the target area so that the target area is pressed downward to form a step, thereby obtaining an intermediate blank; using an elongation tool to elongate the main body area to obtain a free forging forging.

[0033] In the above method, the rectangular blank forged into a single-step forging is subjected to cross-section heading to form a trapezoidal blank with a small upper part and a large lower part, so that when the target area is forged by using the upper anvil, the metal of the target area continuously flows to the side edge, so that the upper edge of the step continuously extends outward, thereby continuously approaching the lower edge of the step in the horizontal direction. By reasonably setting the size of the trapezoidal blank, the upper edge of the step coincides with the lower edge when the step is formed, so that the bulge formed on the side is smaller, thereby greatly reducing unnecessary material and reducing costs. Furthermore, in the method, before the target area is forged by using the upper anvil, a distribution mark is stamped on the top surface of the trapezoidal blank by using a stamping and distributing tool, and the distribution mark separates the trapezoidal blank into a main body area and a target area. Since the contact area between the stamping and distributing tool and the top surface of the trapezoidal blank is smaller, the stamping and distributing tool can quickly penetrate into the top surface of the trapezoidal blank and cut the top surface of the trapezoidal blank. Although a certain amount of collapse corner is still formed at the separated part due to the cohesive action of the metal, the collapse corner is smaller than that formed by direct forging. Therefore, less material is used to compensate for the collapse corner in subsequent processing, thereby saving forging material and further reducing costs. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0035] Figure 1 is a structural schematic diagram of a conventional square forging blank in the background art when a single-step is processed;

[0036] Figure 2 is a structural schematic diagram of a forging produced by the manufacturing method of the single-step titanium alloy forging provided by the embodiment of the present application;

[0037] Figure 3 is a structural schematic diagram of the trapezoidal blank described in the embodiments of the present application;

[0038] Figure 4 is a structural schematic diagram of the embossing and distributing tooling described in the embodiments of the present application;

[0039] Figure 5 is a structural schematic diagram of the embossing and distributing process described in the embodiments of the present application;

[0040] Figure 6 is a structural schematic diagram of the upper flat anvil forging target area described in the embodiments of the present application;

[0041] Figure 7 is a flow chart of the manufacturing method of the single-sided stepped titanium alloy forging provided by the embodiments of the present application.

[0042] In the drawings:

[0043] 1-square forging blank, 2-lower flat anvil, 3-upper flat anvil, 4-spread, 5-corn;

[0044] 100-forging, 200-trapezoidal blank, 300-embossing and distributing tooling. DETAILED DESCRIPTION

[0045] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0046] Embodiment:

[0047] The manufacturing method of the single-sided stepped titanium alloy forging provided by the present embodiment is as shown in Figure 7 , which comprises:

[0048] Step 1: according to the weight and the maximum cross-sectional area of the forging 100 (as shown in Figure 2 ), determine the blanking specification, and according to the blanking specification, carry out blanking to obtain a bar blank. In this step, the weight of the forging 100 is defined as m, the maximum cross-sectional area of the forging 100 is defined as s, the diameter of the bar blank is defined as D, the cross-sectional area of the bar blank is defined as S=ΠD² / 4, the weight of the bar blank is defined as M, considering the control error of the free forging 100 forming process and the spread 4 and the deformation amount in the forming process, so that 1.05m≤M≤1.3m, 1.1s≤S≤1.5s.

[0049] Step 2: elongate the rod blank by using the elongation tool to obtain a rectangular blank. Before the process is carried out, the elongation tool needs to be preheated, and the preheating method is to heat it by using a natural gas furnace, and the heating time is not less than 10 hours, and the temperature of the elongation tool when in use is not less than 200℃, and the rod blank is heated to 30-70℃ below the phase transition point by using an electric furnace before elongation, and the heating time is calculated according to 0.3-1.1min / mm.

[0050] Step 3: change the cross section of the rectangular blank along its length direction by using the upsetting tool to obtain a trapezoidal blank 200 (as shown in Figure 3

[0051] The bottom angle of the trapezoidal blank 200 obtained through this step is defined as a, and 3°≤a≤10°, optionally, the value of a can be 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, etc.

[0052] The height of the trapezoidal blank 200 is defined as H, and h+20mm≤H≤h+40mm, where h is the total height of the forged piece 100, and optionally, the value of H can be h+20mm, h+25mm, h+30mm, h+35mm, h+40mm, etc.

[0053] The horizontal distance of the upper base and the lower base of the trapezoidal blank 200 on one side is defined as L, and L=ΔS, where ΔS is the protruding distance of the step edge part outward from the bottom edge of the square blank 1 when the existing method in the background art is forged. In this way, when the step forging is completed, the step top surface edge is flush with the bottom surface edge.

[0054] More preferably, the bottom angle a of the trapezoidal blank 200 in the embodiment and the height H of the trapezoidal blank 200 have a positive correlation, the greater the height H of the trapezoidal blank 200, that is, the thicker the trapezoidal blank 200, the greater the value of the bottom angle a of the trapezoidal blank 200, on the contrary, if the height of the trapezoidal blank 200 is smaller, the value of the bottom angle a is smaller.

[0055] Step 4: place the trapezoidal blank 200 on the lower anvil 2 so that the bottom surface of the trapezoidal blank 200 is in contact with the lower anvil 2. Of course, the lower anvil 2 can also be preheated in advance, and the preheating method is to heat it by using a natural gas furnace, and the heating time is not less than 10 hours, and the temperature of the elongation tool when in use is not less than 200℃.

[0056] ​Step 5: according to the size of the step, using the embossing and distributing tool 300 (as shown in Figure 4 ) to emboss a distributing mark on the top surface of the trapezoidal blank 200, which separates the trapezoidal blank 200 into a main body area and a target area, as shown in Figure 5 . Before this process, the embossing and distributing tool 300 needs to be preheated, which is heated by a natural gas furnace for no less than 10 hours, and the temperature of the embossing and distributing tool 300 is ensured to be no less than 200℃ when in use. Moreover, the trapezoidal blank 200 is heated to 30-70℃ below the phase transition point by an electric furnace before embossing and distributing, and the heating time is calculated according to 0.3-1.1 min / mm.

[0057] Optionally, the embossing and distributing tool 300 has a large-to-small conical structure from top to bottom, and a fillet is arranged at the corner between the bottom end surface and the side surface of the embossing and distributing tool 300, so that the embossing and distributing tool 300 can easily cut into the top surface of the trapezoidal blank 200. When in use, the embossing and distributing tool 300 is driven to press down by a press or forging equipment, so as to emboss a mark on the top surface of the trapezoidal blank 200, and the depth of the mark is defined as t, 20mm≤t≤40mm, and specifically, t can be 20mm, 25mm, 30mm, 35mm, 40mm, etc. Moreover, the depth t of the mark and the height H of the trapezoidal blank 200 have a positive correlation, that is, the depth of the mark increases with the increase of the thickness of the trapezoidal blank 200, or the depth of the mark decreases with the decrease of the thickness of the trapezoidal blank 200.

[0058] The radius of the fillet is defined as r, 8mm≤r≤15mm. Specifically, r can be 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, etc.

[0059] The width of the embossing and distributing tool 300 is defined as W, 30mm≤W≤60mm, and specifically, W can be 30mm, 40mm, 50mm, 60mm, etc.

[0060] The inclination angle of the side surface of the embossing and distributing tool 300 is defined as β, 2°≤β≤3°, and specifically, β can be 2°, 2.5°, 3°, etc.

[0061] Step 6: the upper anvil 3 is forged to hit the target area by forging equipment, as shown in Figure 6The target area is pressed down to form a step, and an intermediate blank is obtained. Before this step, the upper flat anvil 3 needs to be preheated. The preheating method is to heat it with a natural gas furnace, and the heating time is not less than 10 hours, and the temperature of the upper flat anvil 3 during use is not less than 200°C. Moreover, the trapezoidal blank 200 is heated to 30-70°C below the phase transition point with an electric furnace before forging the step, and the heating time is calculated according to 0.3-1.1 min / mm.

[0062] Because the parting mark has been pressed on the top surface of the trapezoidal blank 200 in advance with the parting press tool 300, the collapse 5 near the step of the body part is smaller when the upper flat anvil 3 is forged to form the step. If the depth of the step is greater than the depth of the parting mark, the target area is forged with the upper flat anvil 3 multiple times, and the parting press tool 300 is used to press a mark at the joint between the step and the body part before each forging.

[0063] In addition, if steps are needed on both sides of the forged piece 100, corresponding steps are also processed on the other side of the trapezoidal blank 200 according to steps 5 and 6.

[0064] Step 7: The body area is elongated with an elongation tool to obtain a free-forged forged piece 100. Before this process, the elongation tool needs to be preheated. The preheating method is to heat it with a natural gas furnace, and the heating time is not less than 10 hours, and the temperature of the elongation tool during use is not less than 200°C. Moreover, the intermediate skin is heated to 30-70°C below the phase transition point with an electric furnace before elongation, and the heating time is calculated according to 0.3-1.1 min / mm.

[0065] The height of the body part of the intermediate blank is the same as the height of the trapezoidal blank 200, which is still H. The elongation tool is used to elongate the thickness, so that the height of the body part of the intermediate blank is reduced to h. During elongation, the collapse 5 at the edge of the body part can also be repaired.

[0066] If necessary, the bulging filler 4 at the edge of the forged piece 100 can be cut off.

[0067] In the method, the rectangular blank forged into the single-sided stepped forging 100 is upset into the trapezoidal blank 200 with the upper small and the lower large, so that when the target area is forged by the upper anvil 3, the metal of the target area constantly flows to the lateral edge, so that the upper edge of the step constantly extends outward, thereby the upper edge of the step constantly approaches the lower edge in the horizontal direction, and by reasonably setting the size of the trapezoidal blank 200, the upper edge of the step is coincided with the lower edge when the step is formed, so that the bulge formed laterally is smaller, and therefore, the unnecessary dressing 4 can be greatly reduced, and the cost is reduced; furthermore, in the method, before the target area is forged by the upper anvil 3, the blanking mark is pressed on the top surface of the trapezoidal blank 200 by the blanking device 300, and the blanking mark separates the trapezoidal blank 200 into the main body area and the target area, since the contact area between the blanking device 300 and the top surface of the trapezoidal blank 200 is smaller, the blanking device 300 can quickly sink into the top surface of the trapezoidal blank 200, and the top surface of the trapezoidal blank 200 is cut, although due to the cohesive property of the metal, a certain amount of the burr 5 is still formed at the separated part, the burr 5 is smaller than the burr 5 directly formed by forging in the background art, so that the material used for compensating the burr 5 is less in the subsequent processing, thereby the material of the forging 100 is more saved, the cost is further reduced, the overall deformation of the forging 100 is uniform, the material utilization is improved, and the quality of the forging 100 is ensured.

[0068] In addition, it should be noted that, in order to prevent the forging 100 from being not forged through due to too small deformation and the end cracking due to too large deformation, the forging ratio of each heating should be between 1.1 and 1.6, and the single deformation amount should be controlled between 10% and 70% during the forging process of each heating.

[0069] The above merely describes the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of the changes or replacements within the technical range disclosed in the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for manufacturing a single-sided stepped titanium alloy forging, characterized in that, include: Step 1: Determine the blanking specifications based on the weight and maximum cross-sectional area of ​​the forging, and cut the blank according to the specifications to obtain the billet; Step 2: Use a drawing tool to draw the bar billet to obtain a rectangular billet; Step 3: Use upsetting fixtures to upset the rectangular billet along its length to obtain a trapezoidal billet that is smaller at the top and larger at the bottom; Step 4: Place the trapezoidal blank on the lower flat anvil, so that the bottom surface of the trapezoidal blank is in contact with the lower flat anvil; Step 5: According to the step size, use an embossing and material distribution tool to press out material distribution marks on the top surface of the trapezoidal blank. The material distribution marks divide the trapezoidal blank into the main area and the target area. Step 6: Use forging equipment to drive the upper flat anvil to forge the target area, so that the target area is pressed down to form a step, and an intermediate billet is obtained; Step 7: Use a drawing tool to lengthen the main body area to obtain a free-forging forging.

2. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 1, characterized in that: In step 1, the weight of the billet is M, and the diameter of the billet is D; 1.05m≤M≤1.3m, where m is the weight of the forging; 1.1s≤S≤1.5s, where s is the maximum cross-sectional area of ​​the forging, and S=ΠD² / 4.

3. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 1, characterized in that: In step 3, the base angle of the trapezoidal blank is α, where 3°≤α≤10°; The height of the trapezoidal billet is H, where h+20mm≤H≤h+40mm, and h is the total height of the forging.

4. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 3, characterized in that: There is a positive correlation between the base angle α of the trapezoidal blank and the height H of the trapezoidal blank.

5. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 1, characterized in that: In step 5, the depth of the material separation mark is t, where 20mm ≤ t ≤ 40mm.

6. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 5, characterized in that: The depth t of the material distribution mark is positively correlated with the height H of the trapezoidal blank.

7. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 5, characterized in that: The imprinting and material distribution fixture has a conical structure that is larger at the top and smaller at the bottom, and the corners between the bottom end face and the side face of the imprinting and material distribution fixture are rounded. The radius of the fillet is r, where 8mm ≤ r ≤ 15mm; The width of the embossing and material distribution fixture is W, 30mm≤W≤60mm; The inclination angle of the side of the embossing and material distribution fixture is β, where 2°≤β≤3°.

8. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 5, characterized in that: In the process of obtaining the intermediate billet in step 6, if the depth of the step is greater than the depth of the material distribution mark, the target area is forged multiple times using an upper flat anvil. Before each forging, the pressing and material distribution tool is used to press out the mark at the part where the step and the main body meet.

9. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 1, characterized in that: Before the bar billet is drawn, before the rectangular billet is upset, before the trapezoidal billet is pressed and divided, and before the intermediate billet is drawn, the billet is heated to 30-70°C below the phase transformation point in an electric furnace. The heating time is calculated at 0.3-1.1 min / mm.

10. The method for manufacturing a single-sided stepped titanium alloy forging according to claim 9, characterized in that: Before use, the drawing tool, the upsetting tool, the upper anvil, the lower anvil, and the stamping and dispensing tool are all preheated in a natural gas furnace for no less than 10 hours, so that the temperature of the drawing tool, the upsetting tool, the upper anvil, the lower anvil, and the stamping and dispensing tool during use is no less than 200°C.

Images