A upsetting method for forging large-sized titanium alloy billets used in aerospace

Abstract

The present invention relates to the technical field of non-ferrous metal hot working, and particularly relates to a upsetting method for forging large-sized titanium alloy billets for aerospace; S1. Forge using the surplus tailings of ordinary steel and make a simple upsetting plate by oneself; S2. Heat the titanium alloy billet, start the charging vehicle to take the billet out of the furnace and load it; S3. Use a 30-ton manipulator to clamp the upsetting plate, place it at the upper end of the billet, and complete the overall upsetting of the billet; S4. Complete the drawing forging of the large-sized titanium alloy billet, and forge it to the specified shape and size according to the process; S5. Continue to complete the drawing and rolling forging of the billet to obtain a bar product that meets the requirements. In the present invention, this method can effectively eliminate the "double-bulging" phenomenon after upsetting, significantly improve the uniformity of the product structure, solve the problems that the "double-bulging" phenomenon occurs in the billet during split-hammer upsetting, resulting in uneven deformation of the bar and unqualified flaw detection of the central part, greatly improve the flaw detection qualification rate of the product, and eliminate the cracking problems caused by the hammer marks of split-hammer upsetting of the billet and the low final forging temperature.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal hot processing, in particular to an upsetting method for forging large-size titanium alloy billets for aerospace use. Background Art

[0002] With the rapid development of equipment in industries such as aerospace, titanium alloy parts are becoming larger and larger, and the specifications of raw materials such as titanium alloy ingots and bars are becoming larger and larger, and the requirements for the uniformity of the organizational performance of bar products are also becoming higher and higher. Usually, the forging process requires multiple fires and repeated upsetting. At present, the diameter size of common 3-ton titanium alloy ingots has reached Φ580mm~Φ600mm, and the cross-sectional size of the billet in the forging process reaches δ500mm~δ600mm. After upsetting, the cross-sectional size of the billet reaches δ700mm~δ800mm, which is far beyond the width of 500mm of the hammer anvil of the 2000-ton fast forging unit. Using the 2000-ton fast forging unit There are also the following problems in upsetting large-sized titanium alloy billets with a 500mm wide hammer anvil: during the upsetting process, the cross-sectional size of the billet will exceed the size of the hammer anvil after expanding to 500mm, and it can only be upset with separate hammers. In fact, upsetting with separate hammers will stretch the billet along the cross section, and the deformation force is difficult to transmit to the core position. The center of the bar moves slowly, and a serious "double belly" phenomenon is prone to occur, that is, the side presents an obvious "I" shape; secondly, upsetting with separate hammers will cause the cross section to form multiple hammer marks at the junction of the separate hammers, which is easy to crack during the subsequent drawing process; finally, due to the irregularity of the billet, the drawing operation is more difficult. Once the temperature is lower than the final forging temperature, the billet will crack and the deformation required by the process cannot be completed.

[0003] At the same time, the serious "double bulging" problem during upsetting of titanium alloy billets will further lead to insufficient deformation in the middle part of the billet length during each fire drawing process. The difference in deformation during multiple fires will accumulate, and ultimately lead to insufficient total deformation in the middle part of the bar length after forming, and the grains cannot be completely broken, which is reflected in the ultrasonic testing results. For the "double bulging" phenomenon of large-sized titanium alloy billets due to upsetting, the main existing methods are to use a crane upsetting cap for upsetting or use a wide flat anvil on the upper and lower flat anvils:

[0004] 1. Using a crane to lift the upsetting cap for upsetting: The crane runs too slowly and is difficult to align. It also requires hanging and unhanging chain buckles, which is difficult to operate, time-consuming and labor-intensive. It cannot guarantee the initial forging temperature of the titanium alloy billet. The titanium alloy forging window is narrow, and a too low final forging temperature will cause severe cracking of the billet, making it impossible to meet the forging process requirements for each fire, seriously affecting product quality and production efficiency. In addition, an additional crane operator will be required, increasing human resource costs. In addition, the upsetting cap is easy to fall off, causing mechanical injuries and posing a safety hazard.

[0005] 2. The upper and lower flat anvils use wide flat anvils: Basically, it is for forging mills with a tonnage of more than 4,500 tons. If the 2,000-ton forging mill replaces the wide hammer anvil, the hammer anvil materials are all made of special die steel. The manufacturing cost of the upper and lower flat anvils is high. At the same time, due to the structural size limitations of the hanging hammer anvil part of the 2,000-ton forging mill, and the width of the card slot for fixing the flat anvil on the moving workbench is already determined, the modification difficulty is relatively large, exceeding the design limit, and there are potential safety hazards. In addition, the wider hammer anvil is not conducive to the drawing out of titanium alloy billets with a small feed amount. It is not realistic to replace the narrow hammer anvil on-site for drawing out after upsetting. Moreover, due to different product specifications and process requirements on-site, if the hammer anvil is repeatedly replaced, it will increase the labor intensity of workers and raise the preheating cost of the hammer anvil.

[0006] Therefore, the above two methods are both infeasible and cannot effectively solve the problem that large-sized titanium alloy billets have "double bellies" due to upsetting and ultimately lead to poor ultrasonic flaw detection uniformity of bar products and unqualified flaw detection in the middle part.

[0007] In summary, developing a method for upsetting large-sized titanium alloy billets used in aerospace forging is still a key problem that urgently needs to be solved in the field of non-ferrous metal hot working technology. Summary of the Invention

[0008] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a method for upsetting large-sized titanium alloy billets used in aerospace forging.

[0009] To achieve the above purpose, the present invention provides the following technical solutions:

[0010] A method for upsetting large-sized titanium alloy billets used in aerospace forging, comprising the following steps:

[0011] S1. Forge using the surplus tailings of ordinary steel and make a simple upsetting plate by oneself;

[0012] S2. Heat the titanium alloy billet, start the charging car to take out the billet from the furnace and load it;

[0013] S3. Use a 30-ton manipulator to clamp the upsetting plate, place it at the upper end of the billet, and complete the overall upsetting of the billet;

[0014] S4. Complete the drawing out forging of the large-sized titanium alloy billet, and forge it to the specified shape and size according to the process;

[0015] S5. Continue to complete the drawing out and rolling round forging of the billet to obtain a bar product that meets the requirements.

[0016] The present invention is further configured as follows: In step S1, the simple upsetting plate is made of steel material (remaining tail material of steel bar), heated in an electric furnace, and prepared by upsetting and forging into a flat square on a 2000-ton quick forging machine set. The main dimensions of the upsetting plate are: length 1000 mm × width 950 mm × thickness 140 mm, and the dimensions of the part with a tong handle are: length 300 mm × width 500 mm × thickness 140 mm.

[0017] The present invention is further configured as follows: In step S1, the 2000-ton quick forging machine set includes three main parts: a 2000-ton press mainframe, a 20-ton manipulator, and a 30-ton manipulator. Among them, the 30-ton manipulator and the 20-ton manipulator are symmetrically distributed on the left and right positions of the 2000-ton press mainframe. The 500-mm-wide upper flat anvil is fixed on the 2000-ton press mainframe, and the 500-mm-wide lower flat anvil is fixed in the clamping groove of the moving workbench of the quick forging machine set and can move with the moving workbench.

[0018] The present invention is further configured as follows: In step S2, titanium alloy large-sized billets with a cross-sectional dimension ≥ 500 mm are heated according to the formulated heating process, that is, in the single-phase region at 1000 - 1180 °C and in the two-phase region at 800 - 960 °C, heated and held in a high-precision electric heating furnace for a specified time. The preheating time in the two-phase region is 0.3D - 0.5D (unit: min), heated to the single-phase region for 0.3D - 0.5D, and heated in the two-phase region for 0.65D - 1.1D, where D is the minimum cross-sectional dimension of the billet (unit: mm). Start the charging car to the furnace door and make preparations for taking out of the furnace.

[0019] The present invention is further configured as follows: In step S3, use the 30-ton manipulator to clamp the upsetting plate, place it at the upper end of the billet, and complete the upsetting of the billet, including the following steps:

[0020] S31. Place the upsetting plate on the square upsetting platform. The square upsetting platform and the upsetting plate are lifted by a crane to the moving workbench of the 2000-ton quick forging machine set, located between the 30-ton manipulator and the 2000-ton press mainframe, close to the lower flat anvil of the 2000-ton press mainframe. Under the transmission of the moving workbench of the 2000-ton quick forging machine set, move the square upsetting platform with the upper-placed upsetting plate to the position directly below the upper flat anvil of the 2000-ton press mainframe;

[0021] S32. Start the 30-ton manipulator 15 - 20 min in advance, move forward along the direction of the 2000-ton press mainframe. The jaws of the 30-ton manipulator clamp firmly at the position of the tong handle of the upsetting plate, rise to the specified height, visually estimate to be close to or exceed the height of the titanium alloy billet after standing on the square upsetting platform, at a position about 2000 mm from the ground;

[0022] S33. Lift the furnace door. The charging car moves forward to clamp the titanium alloy blank, transfers it to the jaws of the 20-ton manipulator within 30 seconds, clamps the blank along the direction of the 2000-ton press mainframe and moves forward to feed the blank, crosses the lower flat anvil, turns 90° and stands on the thermal insulation cotton of the four-sided upsetting platform. The jaws of the 20-ton manipulator open and it retreats about 500 mm along the direction of the 20-ton manipulator;

[0023] S34. The 30-ton manipulator adjusts in time according to the height of the blank, clamps the upsetting plate and moves forward along the direction of the 2000-ton press mainframe, places it directly above the blank. After aligning with the assistance of the blacksmith, the jaws of the 30-ton manipulator loosen and it retreats about 500 mm along the direction of the 30-ton manipulator, leaving the upsetting plate directly above the blank;

[0024] S35. The upper flat anvil of the 2000-ton press mainframe drops, slowly approaches the upsetting plate and applies pressure. Under a pressure of 2000 tons, the upsetting plate drops with the height of the blank to upset the blank. The downward pressure rate is 20 - 50 mm / s. According to the temperature of the blank, the upsetting process can be paused appropriately 2 - 3 times, with each time about 5 s. After the height of the blank drops to the process-specified height, stop applying pressure to complete the upsetting of the blank, and lift the upper flat anvil of the 2000-ton press mainframe.

[0025] The present invention is further configured as: in step S4, for the drawing-forging of the large-sized titanium alloy blank to forge it into the process-specified shape and size, the following steps are included:

[0026] S41. The 30-ton manipulator moves forward along the direction of the 2000-ton press mainframe, clamps the upsetting plate and retreats about 1000 mm along the direction of the 30-ton manipulator. The 20-ton manipulator moves forward along the direction of the 2000-ton press mainframe, picks up the large-sized titanium alloy blank. The four-sided upsetting platform retreats about 1000 mm under the drive of the moving workbench of the 2000-ton quick forging unit to the position where the 500-mm-wide lower flat anvil is directly below the upper flat anvil;

[0027] S42. The 20-ton manipulator clamps the blank and turns it 90° to lay it down horizontally on the lower flat anvil;

[0028] S43. Use the 20-ton manipulator to clamp and flip the large-sized titanium alloy blank. The upper flat anvil of the 2000-ton press mainframe repeatedly presses down and rises, while the lower flat anvil remains stationary, to complete the drawing-forging of the large-sized titanium alloy blank in ways such as squaring, chamfering or squaring and octagonal chamfering or hexagon forming. The pressure-down rate is controlled at 10 - 30 mm / s, and forge it into the process-specified shape and size.

[0029] The present invention is further configured as follows: in step S4, after forging is completed, the final forging temperature of the billet is measured, the material is unloaded from the material cart onto the cooling bracket, air-cooled, polished, and loaded into the furnace for heating, and the above steps are continued to complete multiple rounds of repeated upsetting and drawing forging, and finally step S5 is completed to draw and round the billet to obtain a bar product that meets the requirements.

[0030] Beneficial effects

[0031] Compared with the known public technology, the technical solution provided by the present invention has the following advantages:

[0032] Beneficial effects:

[0033] (1) In the present invention, a simple upsetting plate is made by itself, which is clamped on the upper end of the blank by a 30-ton operating machine, and the lower end of the blank is placed on a square upsetting platform. The large-sized titanium alloy blank is upset as a whole on a 2000-ton fast forging unit. After upsetting, the large-sized titanium alloy blank has a regular shape, which reduces the difficulty of the drawing operation, is deformed evenly, and can smoothly meet the deformation requirements of each fire. The entire operation process is completed by a fast forging machine operator, who only needs to assist in alignment. Compared with the upsetting plate hung by a crane, the alignment is easy, the upsetting plate is not easy to fall off, and there is no need to fix the crane operator, which reduces the human resource cost and reduces the risk of safety accidents.

[0034] (2) In the present invention, the method can effectively eliminate the "double bulging" phenomenon of large-sized titanium alloy billets after upsetting, and the uniformity of the product structure is significantly improved. It solves the problem that the billet produces the "double bulging" phenomenon during upsetting with a separate hammer, which ultimately leads to uneven deformation of the bar and unqualified flaw detection at the center part. The product flaw detection pass rate is greatly improved; and the operation process is fast and smooth, ensuring the initial forging temperature of the titanium alloy billet, eliminating the cracking problem caused by the hammer mark of the billet during upsetting with a separate hammer and the low final forging temperature, and reducing the amount of grinding, thereby improving production efficiency and yield rate.

[0035] (3) In the present invention, the present invention can make full use of the original idle equipment and tooling such as the 30-ton manipulator for forging steel and the square upsetting platform, thereby preventing the equipment from being inflexible in operation due to long-term non-use, improving the utilization rate of idle equipment and tooling, avoiding major modification of the 2,000-ton fast forging unit, saving the cost of purchasing a new wide flat anvil and design modification, and reducing the safety risk caused by equipment modification.

[0036] (4) In the present invention, a method is provided to solve the problem of "double bulging" of large-sized titanium alloy billets for aerospace use during the upsetting process of a 2000-ton fast forging unit. The upsetting plate is forged from ordinary steel scraps, has a simple structure, a material-saving design, does not require maintenance, has a low cost, and is not easily damaged. A single piece can meet long-term use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1It is a process flow chart of a upsetting method for forging large-sized blanks of titanium alloy for aerospace applications. Specific embodiments

[0038] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0039] The present invention will be further described below in conjunction with embodiments.

[0040] Please refer to Figure 1 As shown, a upsetting method for forging large-sized blanks of titanium alloy for aerospace applications includes the following steps:

[0041] Step 1: Forge using the remaining tailings of ordinary steel to make a simple upsetting plate: The simple upsetting plate is made of steel material (steel bar remaining tailings). After being heated by an electric furnace, it is prepared by forging into a flat square on a 2000-ton quick forging machine set. The main dimensions of the upsetting plate are: length 1000 mm × width 950 mm × thickness 140 mm, and the dimensions of the part with a tong handle are: length 300 mm × width 500 mm × thickness 140 mm; The 2000-ton quick forging machine set includes three main parts: a 2000-ton press mainframe, a 20-ton manipulator, and a 30-ton manipulator. Among them, the 30-ton manipulator and the 20-ton manipulator are symmetrically distributed on the left and right sides of the 2000-ton press mainframe. The 500-mm-wide upper flat anvil is fixed on the 2000-ton press mainframe, and the 500-mm-wide lower flat anvil is fixed in the card slot of the moving workbench of the quick forging machine set and can move with the moving workbench;

[0042] 2000-ton press mainframe: Nominal pressure 20 MN, overall frame double-column down-pulling structure, direct drive by oil pump, maximum clear distance 2900 mm, maximum stroke 1400 mm, column spacing 2000×1100 mm, moving workbench size 1610×5000 mm, moving workbench stroke 2×1500 mm;

[0043] 20-ton fully hydraulic direct-moving forging manipulator: mainly composed of a frame, a tong rod, a hanging system, a hydraulic system, a detection system, a lubrication system, an electrical control system and others. The nominal load capacity is 20 tons, the clamping torque is 40 t.m, the rotation speed of the tong head is 1 - 16 r.p.m, and the side shift distance of the tong rod is ±200 mm;

[0044] 30-ton fully hydraulic direct-moving forging manipulator: mainly composed of a frame, tong rod, hanging system, hydraulic system, detection system, lubrication system, electrical control system and others, with a nominal load capacity of 30 tons, a clamping torque of 60 t.m, a tong head rotation speed of 1 - 16 r.p.m, and a tong rod side shift distance of ±210 mm.

[0045] Step 2: Start the charging car to the front of the furnace and make preparations for tapping: The original ingot size of the large-sized TC4 titanium alloy is Φ585mm×1355mm, and the size of the titanium alloy billet during forging is 550mm×1200mm. Heat the large-sized titanium alloy billet with a cross-sectional size ≥500mm according to the specified heating process, with the β transformation temperature T β = 990 ± 10 °C, heat it in a high-precision resistance furnace according to the specified process, with heating temperatures of 1150 ± 10 °C, 1060 ± 10 °C, 960 ± 10 °C and multiple heating stages at T β 30 - 50 °C below, heat in sections, with a preheating time of 165 - 180 min at 850 °C - 900 °C, a holding time of 210 - 240 min at 1150 °C and 1060 °C, and a heating time of 425 min at T β 30 - 50 °C below, make preparations for tapping. After reaching the temperature, the charging car takes out the billet.

[0046] Step 3: Use the 30-ton manipulator to clamp the upsetting plate, place it at the upper end of the billet, and complete the upsetting of the billet, including the following steps:

[0047] 31) Place the upsetting plate on the square upsetting platform (made of cast steel, with dimensions of 1600mm in length × 1600mm in width × 800mm in height). The square upsetting platform and the upsetting plate are lifted by a crane to the moving workbench of the 2000-ton quick forging unit, located between the 30-ton manipulator and the main body of the 2000-ton press, close to the lower flat anvil of the 2000-ton press main body, and under the transmission of the moving workbench of the quick forging unit, move to directly below the 2000-ton press main body;

[0048] 32) Start the 2000-ton quick forging unit half an hour in advance and move forward along the direction of the 2000-ton press main body. The jaws of the 30-ton manipulator clamp the handle position of the upsetting plate, lift the upsetting plate to a height of about 2000mm, and keep it horizontal;

[0049] 33) Lift the furnace door, take out the titanium alloy billet, the charging car moves forward to clamp the titanium alloy billet, transfer it to the jaws of the 20-ton manipulator within 30s by the charging car, cross the lower flat anvil, feed (in the direction of the 2000-ton press main body) to the square upsetting platform (lined with a 20mm-thick heat-insulating cotton on the upper layer), turn 90° to stand up the titanium alloy billet, cover the upper end of the billet with heat-insulating cotton, and under the command of the forging worker, the operator adjusts the streamline direction of the billet to be perpendicular to the square upsetting platform;

[0050] 34) The 30-ton manipulator is adjusted in a timely manner according to the height of the blank, and advances along the direction of the 2000-ton press mainframe while clamping the upsetting plate, places it directly above the titanium alloy blank, adjusts the position, and after aligning with the assistance of the blacksmith, the upper flat anvil on the 2000-ton press mainframe drops to the position of the upsetting plate on the upper end face of the blank. The jaws of the 30-ton manipulator are loosened and it retreats about 500 mm along the direction of the 30-ton manipulator, leaving the upsetting plate directly above the blank.

[0051] 35) The upper flat anvil on the 2000-ton press mainframe drops, slowly approaches the upsetting plate, and applies pressure. Under a pressure of 2000 tons, the upsetting plate drops with the height of the blank under the action of the upper flat anvil, and the blank is upset. The upsetting deformation amount is controlled at 45%, and the pressing rate is 30 - 40 mm / s. According to the temperature of the blank, the upsetting process can be paused 2 - 3 times, with each time about 5 s, to prevent the temperature rise of the blank. After the height of the blank drops to the process-specified height H = 660 ± 10 mm (the cross-sectional dimension expands to 740 mm × 740 mm), the pressure application is stopped, the upsetting of the blank is completed, and the upper flat anvil on the 2000-ton press mainframe is lifted.

[0052] Step Four: Complete the drawing forging of the large-sized titanium alloy blank to the process-specified shape and dimensions, including the following steps:

[0053] 41) Along the direction of the 2000-ton press mainframe, the 30-ton manipulator advances, clamps the upsetting plate and retreats about 1000 mm along the direction of the 30-ton manipulator. The 20-ton manipulator advances along the direction of the 2000-ton press mainframe, picks up the large-sized titanium alloy blank (with the blank streamline in the up-down direction), and the four-sided upsetting platform retreats about 1000 mm (in the direction of the 30-ton manipulator) driven by the moving workbench of the 2000-ton quick forging unit until the 500-mm-wide lower flat anvil is located directly below the upper flat anvil.

[0054] 42) The 20-ton manipulator clamps the blank between the upper and lower flat anvils (with the blank streamline in the up-down direction) and rotates the blank 90° to lay it down horizontally on the lower flat anvil.

[0055] 43) Use the 20-ton manipulator to clamp and flip the large-sized titanium alloy blank. With the blank streamline in the horizontal direction and in the coaxial direction with the manipulator, complete the forging of square-making, chamfering and drawing in 3 - 4 passes under the action of the 2000-ton press. The deformation amount is controlled at 45%, and the deformation rate is 10 - 20 mm / s. Draw and trim to the dimensions of 550 mm × 1200 mm, and air-cool.

[0056] Step Five: After grinding the defects, reload the furnace for heating, and according to the above method T βRepeatedly upset the whole billet at 30 - 50°C for multiple times until H = 660 ± 10 mm (cross-sectional size 740 mm × 740 mm), square it, chamfer it (size 550 mm × 1200 mm), and finally elongate and roll it into Φ440(0, +5)mm × ~2100 mm to obtain a qualified bar product; use a band saw to divide the bar into four equal parts along the length direction, number them -1, -2, -3, -4 in sequence from head to tail along the streamline, and machine it on a lathe to Φ429(-0.2, +0.2)mm with a surface roughness Ra ≤ 3.2 μm.

[0057] Randomly select two heat numbers of titanium alloy bars forged by upsetting and elongating according to the above method, and perform ultrasonic flaw detection according to GB / T5193 - 2020 "Ultrasonic Inspection Method for Titanium and Titanium Alloy Processed Products". The results are shown in Table 1:

[0058] Table 1 Flaw Detection Results of Titanium Alloy Bars of Two Heat Numbers

[0059]

[0060] It can be seen from the flaw detection results of the bars in Table 1 above that the overall flaw detection of the titanium alloy bars obtained by this method is uniform, meeting the requirements of Grade B of GB / T 5193 - 2020 standard. There is no longer the situation that the flaw detection of the core noise value of 0 - +3 dB is unqualified. The method of the present invention eliminates the phenomenon of coarse grains in the core of the bar caused by "double bulges" during upsetting, as well as non-uniform and unqualified flaw detection.

[0061] Based on existing equipment such as a 2000-ton quick forging machine (including a 2000-ton press mainframe, a 20-ton manipulator, and a 30-ton manipulator), a billet loading vehicle, a high-precision box-type electric heating furnace, etc., and tooling such as a square upsetting platform and 500-mm-wide upper and lower flat anvils, the present invention uses the surplus tailstock steel bar to make a simple auxiliary tooling (upsetting plate with a clamp handle) through heating and forging methods, and invents a method that can solve the "double bulges" generated during the upsetting process of large-sized titanium alloy billets for aerospace applications on a 2000-ton quick forging machine. The upsetting plate is forged from surplus tailstock of ordinary steel, with a simple structure, material-saving design, no need for maintenance, low cost, and not easily damaged. Making one can meet the long-term use requirements.

[0062] This method uses a self-made simple upsetting plate, which is clamped by a 30-ton manipulator and placed at the upper end of the billet. The lower end of the billet is placed on a square upsetting platform, and the overall upsetting of the large-sized titanium alloy billet is realized on a 2000-ton quick forging machine. After upsetting, the shape of the large-sized titanium alloy billet is regular, reducing the difficulty of elongation operation, with uniform deformation, and can smoothly complete the deformation requirements specified for each heat; and the entire operation process is completed by one quick forging machine operator, and the blacksmith only needs to assist in aligning. Compared with using a crane to lift the upsetting plate, it is easier to align, the upsetting plate is not easily detached, and there is no need to fix the crane operator, which not only reduces the human resource cost but also reduces the risk of safety accidents.

[0063] The invention discloses an upsetting method for forging large-size titanium alloy billets for aerospace use, which can effectively eliminate the "double bulging" phenomenon after upsetting, significantly improves the uniformity of product structure, solves the problem that the billet produces the "double bulging" phenomenon during upsetting with separate hammers, and ultimately leads to uneven deformation of the bar and unqualified flaw detection at the center part, and greatly improves the qualified rate of product flaw detection; and the operation process is fast and smooth, which ensures the initial forging temperature of the titanium alloy billet, eliminates the cracking problem caused by the hammer mark of the separate hammer upsetting and the low final forging temperature of the billet, reduces the amount of grinding, and improves production efficiency and yield rate; the utilization frequency of the 30-ton manipulator is low, and the invention can make full use of the original 30-ton manipulator for forging steel, the square upsetting platform and other idle equipment and tooling, prevents the equipment from being inflexible due to long-term non-use, improves the utilization rate of idle equipment and tooling, avoids major modification of the 2000-ton fast forging unit, saves the cost of purchasing a new wide flat anvil and design modification, and reduces the safety use risk caused by equipment modification.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. 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 will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. Upsetting method for forging large-sized titanium alloy billets for aerospace applications It is characterized in that it includes the following steps: S1. Use ordinary steel scraps to forge and make simple upsetting plates; S2, heating the titanium alloy billet, starting the material car to take out of the furnace and load the material; S3. Use a 30-ton manipulator to clamp the upsetting plate, place it on the top of the blank, and complete the upsetting of the entire blank, including the following steps: S31. Place the upsetting plate on the square upsetting platform. Use a crane to lift the square upsetting platform and the upsetting plate to the mobile workbench of the 2000-ton fast forging unit. The platform is located between the 30-ton manipulator and the 2000-ton press mainframe, close to the lower flat anvil of the 2000-ton press mainframe. Move the square upsetting platform with the upsetting plate on it to the mobile workbench of the 2000-ton fast forging unit. Directly below the flat anvil on the main machine of a 2000-ton press; S32. Start the 30-ton manipulator 15 to 20 minutes in advance and move it in the direction of the 2000-ton press. The 30-ton manipulator jaws should firmly clamp the upsetting plate clamps and rise to the specified height. Visually check that the height is close to or exceeds the height of the titanium alloy billet after the square upsetting platform is erected, 2000 mm above the ground. S33. Lift the furnace door. The reclaimer moves forward to clamp the titanium alloy billet. Within 30 seconds, the billet is transferred to the jaws of the 20-ton manipulator. The billet is clamped in the direction of the 2000-ton press mainframe and fed forward. The billet straddles the lower anvil, turns 90 degrees, and stands on the insulation cotton of the square upsetting platform. The jaws of the 20-ton manipulator open, and the billet is withdrawn 500mm in the direction of the 20-ton manipulator. S34, 30-ton manipulator is adjusted in time according to the height of the blank. It moves forward along the direction of the 2000-ton press main machine, holding the upsetting plate and placing it just above the blank. After alignment with the assistance of the forger, the jaws of the 30-ton manipulator are loosened and it moves back 500mm along the direction of the 30-ton manipulator, leaving the upsetting plate just above the blank. S35. The flat anvil on the 2000-ton press machine falls down and slowly approaches the upsetting plate. Pressure is applied. Under the 2000-ton pressure, the upsetting plate descends along with the height of the blank to perform upsetting of the blank. The downward pressing rate is 20-50 mm / s. Depending on the temperature of the blank, the upsetting process is paused 2-3 times, each time for 5 seconds. After the blank height drops to the specified height, pressure is stopped, the blank upsetting is completed, and the flat anvil on the 2000-ton press machine is pulled up. S4. Complete the drawing and forging of large-sized titanium alloy billets to the shape and size specified by the process, including the following steps: S41. The 30-ton manipulator moves forward in the direction of the 2000-ton press, clamps the upsetting plate, and moves back 1000mm in the direction of the 30-ton manipulator. The 20-ton manipulator moves forward in the direction of the 2000-ton press, clamps the large-sized titanium alloy billet, and the square upsetting platform, driven by the moving worktable of the 2000-ton fast forging unit, moves back 1000mm until the 500mm-wide lower anvil is directly below the upper anvil. S42, 20-ton manipulator clamps the blank, turns it 90°, and lays it forward, horizontally on the lower anvil; S43. Use a 20-ton manipulator to clamp and flip a large-sized titanium alloy billet. The upper flat anvil on the 2000-ton press mainframe repeatedly presses down and rebounds, while the lower flat anvil remains stationary, to complete the upsetting forging of the large-sized titanium alloy billet in the ways of square forging, chamfering, or square forging, octagonal chamfering, or hexagonal forging. Control the pressing rate at 10 - 30 mm / s and forge it to the shape and size specified by the process. S5. Continue to complete the upsetting and rounding forging of the billet to obtain a bar product that meets the requirements.

2. The upsetting method for forging large-sized titanium alloy billets for aerospace use according to claim 1, characterized in that, In step S1, the simple upsetting plate is prepared by upsetting and forging the surplus tailstock of a steel bar after heating in an electric furnace on a 2000-ton quick forging unit. The main dimensions of the upsetting plate are: length 1000 mm × width 950 mm × thickness 140 mm, and the dimensions of the part with a tong handle are: length 300 mm × width 500 mm × thickness 140 mm.

3. A upsetting method for forging large-sized titanium alloy billets for aerospace applications according to claim 2, characterized in that, In step S1, the 2000-ton quick forging unit consists of three main parts: a 2000-ton press mainframe, a 20-ton manipulator, and a 3-ton manipulator. Among them, the 30-ton manipulator and the 20-ton manipulator are symmetrically distributed on the left and right sides of the 2000-ton press mainframe. The 500-mm-wide upper flat anvil is fixed on the 2000-ton press mainframe, and the 500-mm-wide lower flat anvil is fixed in the card slot of the moving workbench of the quick forging unit and can move with the moving workbench.

4. A upsetting method for forging large-sized titanium alloy billets for aerospace applications according to claim 1, characterized in that, In step S2, heat a large-sized titanium alloy billet with a cross-sectional size ≥ 500 mm according to the specified heating process, that is, in the single-phase region at 1,000 - 1,180 °C and in the two-phase region at 800 - 960 °C. Heat and hold it in a high-precision electric heating furnace for the specified time. The preheating time t in the two-phase region is 0.3 min / mm × D - 0.5 min / mm × D, where the unit of time t is min, the heating time t for heating to the single-phase region is 0.3 min / mm × D - 0.5 min / mm × D, where the unit of time t is min, and the heating time t in the two-phase region is 0.65 min / mm × D - 1.1 min / mm × D, where the unit of time t is min, and D is the minimum cross-sectional size of the billet, with the unit of mm. Start the charging car to the furnace door and make preparations for discharging.

5. The upsetting method for forging large-sized titanium alloy blanks for aerospace use according to claim 1, characterized in that, In step S4, after forging, measure the final forging temperature of the billet. The charging car unloads the billet onto the cooling bracket, and it is air-cooled, polished, and then charged into the furnace for heating. Continue to complete the multi-pass upsetting and drawing forging according to the above process steps, and finally complete the drawing and rounding of the billet to obtain a bar product that meets the requirements.

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