Titanium alloy barrier segment machining method

Abstract

The application discloses a titanium alloy partition plate segment processing method, which comprises the following steps in sequence: fan-shaped raw material blanking, deburring, rounding, welding, heat treatment, flanging, thermal bulging, cutting, pickling, welding and cutting, and finally the accurate shape of the titanium alloy partition plate segment is obtained. The titanium alloy partition plate segment which is not suitable for integral bulging is split into two parts along the axial direction, the inner tangent cone and the inner inscribed cone are used to simulate the unfolded shape, and then the two parts are welded to form the titanium alloy partition plate segment, so that the complex outer shape is divided into two relatively easy-to-form parts, high-quality forming of the most difficult-to-form spherical part is realized, and forming wrinkles are avoided. The titanium alloy partition plate segment is fixed through the flanging structure during bulging, and the cylindrical surface on the titanium alloy partition plate segment is used as the reference and support during cutting. The titanium alloy partition plate segment processed finally has high quality, accurate size and high processing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine processing technology, and particularly relates to a method for processing titanium alloy partition sections of aero-engines. Background Technology

[0002] An aircraft engine is a highly complex and precise thermodynamic machine. As the heart of an aircraft, it not only powers the aircraft's flight but also serves as a vital driving force for the development of the aviation industry. Every major transformation in the history of human aviation has been inseparable from the technological advancements in aircraft engines.

[0003] like Figure 1 The image shows a titanium alloy bulkhead section for an aircraft engine, manufactured from TA12A sheet metal. The part is shaped like a bottomless wine jar, with a profile tolerance of no more than 1. It is permitted to have two axial welds and one circumferential weld, and is shaped like a bulging wine jar. Due to the shape limitations, it cannot be formed using a single bulging method, and it also includes spherical portions. Figure 1 The machining of the H2 position is prone to wrinkles, and the appearance quality of the part is difficult to meet the design and assembly requirements. Therefore, it is necessary to propose a machining method for titanium alloy partition sections of aero-engines to meet the quality requirements of part shape and dimensional accuracy. Summary of the Invention

[0004] This invention aims to provide a method for processing titanium alloy partition segments. It employs a reasonable parting and segmented bulging structure to accurately form the dimensions, control the welding fit dimensions and welding deformation, and achieves the quality requirements of meeting the size and shape accuracy of the titanium alloy partition segments.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] Processing methods for titanium alloy partition sections include,

[0007] Step 1: Cutting the titanium alloy sheet into two fan-shaped blanks, with the large arc ends of both fan-shaped blanks having a serrated structure.

[0008] Step 2: Deburring, removing burrs from the edges of the fan-shaped fabric;

[0009] Step 3: Rounding. Round the two fan-shaped pieces of raw material separately, so that the two radial sides of the fan-shaped raw material come together to form a conical cylinder.

[0010] Step 4: Welding. Weld the two radial sides of the conical cylinder corresponding to the fan-shaped material at the point where they meet.

[0011] Step 5: Heat treatment to remove welding stress from Step 4;

[0012] Step six: turn up the edges, bend the sawtooth structure on the conical cylinder corresponding to the large circular arc end of the fan-shaped material, and the bending direction is outward;

[0013] Step seven: hot forming, use thermal expansion to obtain the profile and size of the titanium alloy partition section;

[0014] Step eight: cutting, remove the sawtooth structure after thermal expansion of the two conical cylinders;

[0015] Step nine: pickling, remove the oxide layer on the surface of the two conical cylinders;

[0016] Step ten: welding, butt joint and weld the large outer diameter end faces of the two conical cylinders to obtain the titanium alloy partition section;

[0017] Step eleven: cutting, cut the excess shape of the titanium alloy partition section obtained in step ten to obtain the final shape and size of the titanium alloy partition section.

[0018] As an option, in step one, the titanium alloy partition section is divided into two parts along the axial direction with the radial cross-section outer diameter maximum in the titanium alloy partition section part drawing as the division surface, and then the coaxial inscribed circular cone and coaxial tangent circular cone of the two parts are respectively unfolded as approximate structures to obtain the unfolded size of the two fan-shaped materials.

[0019] As an option, when the coaxial inscribed circular cone and coaxial tangent circular cone are unfolded, they respectively extend a distance to both ends along their generatrix direction.

[0020] As an option, in step four, the two radial edges of the fan-shaped material need to be polished before welding, then positioned by argon arc welding, and then automatically argon arc welded by the filler wire method. After welding, the weld is ground and leak detection is performed.

[0021] As an option, in step five, vacuum heat treatment is used to remove welding stress, and then the temperature is kept at 500-540℃ for 90-120min, and then cooled to below 400℃ and argon is filled for rapid cooling.

[0022] As an option, in step six, the root of the sawtooth structure is heated, and then the edges are bent outward until the sawtooth structure is perpendicular to the axis of the conical cylinder.

[0023] As an option, in step seven, the thermal expansion temperature is 750-780℃, the sawtooth structure after turning up the edges of the conical cylinder is pressed by the edge ring, and then thermal expansion is performed from the inside of the conical cylinder.

[0024] As an option, in step eight, a five-axis laser cutting machine is used to cut off the turned-up sawtooth structure on the conical cylinder with a sample plate to ensure that the shape and size of the cut end face meet the requirements.

[0025] As an alternative, the interval time between the step nine and the step ten is not more than 8 hours, and the step ten is carried out after the welding.

[0026] As an alternative, in the step eleven, the cylindrical surface of the conical cylinder after the thermal expansion is used as a positioning reference and a support surface to find the alignment, and then the profile cutting is carried out.

[0027] The processing method has the following characteristics:

[0028] (1) The titanium alloy partition section which is not suitable for integral expansion is divided into two parts along the axial direction, the inner tangent cone and the inscribed cone are used to simulate the unfolded shape, and then the welding is carried out to form the two parts, so that the complex profile is divided into two relatively easy-to-form parts, the high-quality forming of the most difficult-to-form spherical part is realized, and the forming wrinkles are avoided;

[0029] (2) The sawtooth structure is increased, the fixed position during the expansion is formed by the flanging process, and the axial movement during the expansion is prevented;

[0030] (3) The cylindrical straight wall section of the titanium alloy partition section is used as a reference and support during the second cutting, so that the coaxiality and runout value of the entire titanium alloy partition section meet the requirements.

[0031] Compared with the existing forming method, the processing method of the titanium alloy partition section of the aircraft engine proposed by the present application realizes the accurate forming of the shape of the part by reasonably dividing the blank structure and scientifically determining the parting position, adopting an optimized process route, and using a simple thermal expansion die, which ensures the shape and size precision of the part, and greatly improves the processing efficiency and the quality of the part. The processing method has been used in the field, and the purpose and requirements of the present application have been achieved. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is the front view of the titanium alloy partition section;

[0033] Figure 2 is the unfolded view of the fan-shaped blank;

[0034] Figure 3 is the front view of the conical cylinder flanging;

[0035] Figure 4 is the top view of the conical cylinder flanging. DETAILED DESCRIPTION

[0036] The application will be further described in conjunction with the accompanying drawings and specific embodiments, but should not be understood as the scope of the subject matter described herein is limited to the following embodiments, any modifications, substitutions and changes made according to ordinary technical knowledge and conventional means without departing from the above technical idea of the application are included in the scope of the application.

[0037] As shown in the figure, the method for processing the titanium alloy partition segment of the aero-engine designed by the application comprises the following steps: Figures 1-4

[0038] Step 1: blanking, cutting the titanium alloy plate into two fan-shaped blanks, the blanking idea is to cut the titanium alloy partition segment along the maximum diameter (H2) into two parts (corresponding to A and B in the figure), and the two parts are designed according to the minimum bulging principle, the blank adopts a conical cylinder structure with serrated flanging, the conical cylinder has a 15-20mm allowance at the axial ends, and the large end has a 15-20mm flange allowance based on the aforementioned allowance for unfolding; Figure 1 Figure 1 Step 2: deburring, removing the burrs on the edge of the fan-shaped blank;

[0039] Step 3: rounding, rounding each fan-shaped blank into a conical cylinder;

[0040] Step 4: welding, welding the conical cylinder along the butt joint edge;

[0041] Step 5: heat treatment, removing the welding stress;

[0042] Step 6: flanging, bending the edge by heating the root of the serration with a blowtorch;

[0043] Step 7: hot forming, hot bulging to ensure the shape and size accuracy of the part;

[0044] Step 8: cutting, cutting the serrated flange on the large end face of the conical cylinder to ensure that the gap between the butt joint end faces is not greater than 0.16mm;

[0045] Step 9: pickling, removing the surface oxide layer of the conical cylinder;

[0046] Step 10: welding, welding the two conical cylinders after splicing the large outer diameter ends;

[0047] Step 11: cutting: cutting the outer shape to obtain the final contour size of the titanium alloy partition segment.

[0048] Step 1: cutting the two parts, which correspond to

[0049] Step 1: cutting the two parts, which correspond to Figure 1 ​​The left and right sides of the H2 section are formed by rotating the H1 line (i.e. the generatrix of the inscribed frustum) around the axis of the titanium alloy partition section and intersecting with the two end faces to form an inscribed frustum. The inscribed frustum extends 15-20mm along the small outer diameter end and 25-30mm along the large outer diameter end.

[0050] The outer diameter end of the inscribed frustum has a flanged structure, and the flange is a hand-made flange with a serrated structure.

[0051] The inscribed frustum is determined by the generatrix H1, and lies on the central section of the titanium alloy partition segment. Figure 1 Busbar H1 is lower than the busbar of the titanium alloy partition section and tangent to the busbar of the titanium alloy partition section (the tangent point is...). Figure 1 In the R2 section, the busbar H1 intersects the left end face and the end face at H2 of the titanium alloy partition section, with height differences of h1 and h2 respectively, and h1≈h2.

[0052] The inner frustum is formed by rotating the H3 line around the axis of the titanium alloy partition segment, intersecting the end face at H2 and the right end face. The inner frustum extends 15-20 mm along the smaller outer diameter end and 25-30 mm along the larger outer diameter end. The generatrix H3 of rotation lies on the central section of the titanium alloy partition segment. Figure 1 The busbar H3 is the line connecting the intersection of the end face at H2, the right end face, and the center section, and is offset by 1mm from the axis of the titanium alloy partition section.

[0053] like Figure 2 The large arc ends of the two fan-shaped raw materials have a uniformly distributed serrated structure. The width of the serrated end face is 10-12, the groove width is 1±0.2, and it is evenly divided along the central angle of the fan-shaped circle. At the large arc end of the fan-shaped raw material, it is offset downward by 10-20mm.

[0054] In step 2, a file is used to remove the burrs around the fan-shaped material.

[0055] In step 3, a three-axis rolling mill is used to roll the fan-shaped raw material into a conical cylinder.

[0056] Step 4: Before welding, polish the end faces of the butt joint to be welded within a width of not less than 15mm on both sides. Before welding, use an argon arc welding machine to perform tack welding on the parts, ensuring that the welding gap at the butt joint is not greater than 0.1mm and the misalignment is not greater than 0.1mm. Then, use an automatic argon arc welding machine to perform automatic argon arc welding using the filler wire method to ensure that the butt weld at the generatrix of the conical cylinder is fully penetrated and defect-free.

[0057] After automatic argon arc welding in step 4, the weld needs to be ground to ensure that the weld protrudes no more than 0.25mm above the base material, and the weld is inspected using the kerosene penetration test to ensure that there is no leakage for 5 minutes.

[0058] The heat treatment in step 5 is vacuum heat treatment, with a vacuum furnace pressure less than or equal to 1.33 × 10⁻⁶. -1 Pa, heat up and hold at 500-540℃ for 90-120 minutes, then cool down to below 400℃ and rapidly cool with argon gas to remove welding stress. The time from welding completion to heat treatment completion shall not exceed 20 days.

[0059] In step 6, the flanging is done manually. A blowtorch is used to heat the root of the groove at the large outer diameter end, and the flanging is done outward along the root of the groove, with the flanged surface perpendicular to the axis of the conical cylinder.

[0060] In step 7, the thermal expansion forming process uses a thermoforming machine heated to 750–780℃. During thermal expansion forming, a mold structure with a pressure ring is used. As the machine descends, the mold presses down on the flange of the conical cylinder. The machine continues to descend, pressing to the bottom and holding at that temperature for 3–5 minutes. Two conical cylinders are formed, corresponding to the original shapes. Comparing them with the template, the gap should not exceed 0.3mm. The male and female molds used in thermal expansion forming are... Figure 1 The shapes of the medium-titanium alloy partition sections are consistent. 1Cr18Ni9Ti is used as the material for the male and female molds, and the male and female molds are reduced accordingly based on the coefficient of thermal expansion of 0.99695.

[0061] In step 8, the cutting equipment is a five-axis laser cutting machine. The template is used to scribing and cut the flanges of the large outer diameter end faces of the two conical cylinders. After cutting, the large outer diameter end faces of the two conical cylinders are joined together in a limited state, requiring the gap and misalignment to be no more than 0.16mm.

[0062] In step 9, acid washing removes the oxide layer from the surfaces of the two conical cylinders.

[0063] In step 10, the time between welding and the end of pickling should not exceed 8 hours, the gap between weld joints should not exceed 0.16mm, and the misalignment should not exceed 0.16mm. Before welding, the surface should be cleaned and no stains are allowed. Argon gas should be passed through both the inner and outer sides of the conical cylinder for 3-5 minutes. The two conical cylinders should be welded together along the H2 surface to form a single part. After welding, the gap between the part and the template should not exceed 1mm. After welding, the weld should be inspected for kerosene penetration, and no penetration is allowed after 5 minutes. The weld should be inspected by X-ray according to the corresponding welding technical standards and weld grade. Defects not allowed by the standard are not allowed.

[0064] In step 11, the cutting is done using a straight wall ( Figure 1 Using the cylindrical surface corresponding to the left part of H2 as the reference for positioning and support, align the straight wall with a circular runout of no more than 0.1, cut the diameter ΦD2, ensure the coaxiality Φ0.4 relative to the straight wall, cut the end of the straight wall, and ensure L±0.3.

[0065] The description of the application herein is not intended to be detailed and is well known to those skilled in the art. Although the above describes the specific embodiments of the application in order to facilitate the understanding of the application for those skilled in the art, it should be clear that the application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the application defined and determined by the appended claims, and all the applications using the concept of the application are within the scope of protection.

Claims

1. A method for processing titanium alloy partition segments, characterized in that: include, Step 1: Cutting the titanium alloy sheet into two fan-shaped blanks, with the large arc ends of both fan-shaped blanks having a serrated structure. Step 2: Deburring, removing burrs from the edges of the fan-shaped fabric; Step 3: Rounding. Round the two fan-shaped pieces of raw material separately, so that the two radial sides of the fan-shaped raw material come together to form a conical cylinder. Step 4: Welding. Weld the two radial sides of the conical cylinder corresponding to the fan-shaped material at the point where they meet. Step 5: Heat treatment to remove welding stress from Step 4; Step 6: Fold the edge. Bend the serrated structure on the conical cylinder corresponding to the large arc end of the fan-shaped material, bending it towards the outside of the conical cylinder. Step 7: Hot forming, using thermal expansion to obtain the profile and dimensions of the titanium alloy partition section from the two conical cylinders; Step 8: Cutting to remove the serrated structure of the two conical cylinders after thermal expansion; Step 9: Pickling to remove the oxide layer from the surfaces of the two conical cylinders; Step 10: Welding. Connect and weld the large outer diameter ends of the two conical cylinders to obtain the titanium alloy partition section. Step 11: Cutting. Cut off the excess shape of the titanium alloy partition segment obtained by welding in Step 10 to obtain the final shape and dimensions of the titanium alloy partition segment. In step one, the titanium alloy partition segment is divided into two parts along the axial direction, with the largest radial cross-sectional outer diameter in the part drawing as the dividing surface. Then, the coaxial inscribed frustum and coaxial inscribed frustum of the two parts are used as approximate structures to obtain the unfolded dimensions of the two fan-shaped blanks. When the coaxial inscribed frustum and coaxial inscribed frustum are unfolded, they are extended a certain distance to both ends along their generatrices. In step seven, the thermal expansion temperature is 750-780℃. A pressure ring is used to press the serrated structure of the flanged conical cylinder, and then thermal expansion is performed from the inside of the conical cylinder.

2. The method for processing titanium alloy partition segments according to claim 1, characterized in that: In step four, the two radial edges of the fan-shaped material need to be polished before welding. Then, tack welding is performed by argon arc welding, followed by automatic argon arc welding by filler wire method. After welding, the weld is ground and weld leakage is detected.

3. The method for processing titanium alloy partition segments according to claim 1, characterized in that: In step five, vacuum heat treatment is used to relieve welding stress. The temperature is held at 500-540℃ for 90-120 minutes, and then cooled to below 400℃ and rapidly cooled with argon gas.

4. The method for processing titanium alloy partition segments according to claim 1, characterized in that: In step six, the root of the sawtooth structure is heated, and then the edge is bent outward until the sawtooth structure is perpendicular to the axis of the conical cylinder.

5. The method for processing titanium alloy partition segments according to claim 1, characterized in that: In step eight, a five-axis laser cutting machine is used in conjunction with a template to remove the serrated edge structure on the conical cylinder, ensuring that the shape and size of the cut end face meet the requirements.

6. The method for processing titanium alloy partition segments according to claim 1, characterized in that: The interval between steps nine and ten shall not exceed 8 hours, and a penetration test shall be performed after welding in step ten.

7. The method for processing titanium alloy partition segments according to claim 1, characterized in that: In step eleven, the cylindrical surface of the conical cylinder with a cylindrical surface after thermal expansion is used as the positioning reference and support surface for alignment, and then the outer shape is cut.

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