Method for processing an aeroengine lobed mixer and a bulging die

Abstract

The application discloses an aero-engine wave lobe mixer processing method and an expanding die. The expanding die comprises an outer expanding lobe, an inner expanding lobe, an outer guide rail and an inner guide rail. When the wave lobe mixer is processed, the following steps are sequentially implemented: a lower fan-shaped blank is prepared, deburring is performed, rounding is performed, a conical cylinder is welded, heat treatment is performed to remove welding stress, pre-expanding is performed, heat treatment is performed to remove expanding stress, polishing is performed, expanding forming is performed, fluorescence inspection is performed, and the excess size of the outer shape is cut. The wave lobe mixer processed by the method has only one longitudinal weld, the size of the mixer profile is accurate, the precision is high, and the technical requirements are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engine processing, and particularly relates to an aero-engine wave lobe mixer processing method and an expanding die for forming. BACKGROUND

[0002] As shown in Figs. Figure 1 and Figure 2 , it is a wave lobe mixer on an aero-engine, and the wave lobe mixer has 24 wave lobes which are uniformly distributed in the circumferential direction. According to the technical requirements, the wave lobe mixer can only have one longitudinal weld (i.e. the weld along the axial direction of the wave lobe mixer). Since the wave lobe mixer adopts an overall structure design, the diameter size is large, and the processing precision requirement is high, therefore, the traditional wave lobe mixer forming method is no longer applicable.

[0003] At present, there is no record about the overall processing method of the aero-engine wave lobe mixer in the prior art, therefore, it is necessary to propose an aero-engine wave lobe mixer overall processing method to meet the multiple requirements of the part shape, size precision and the number of welds. SUMMARY

[0004] The application aims to provide an aero-engine wave lobe mixer processing method and an expanding die, which meet the overall processing requirement of only one longitudinal weld, and the processed wave lobe mixer meets the quality requirements of the part size and shape precision.

[0005] The core idea of the application is that the wave lobe mixer is processed by accurately controlling the shape of the raw material, cooperating with the overall forming mode of welding, internal expansion and external shrinkage. Under the premise of reserving one weld, the die is expanded as a whole, and finally the quality requirements of the part size and shape precision are achieved by laser cutting the wave shape.

[0006] In order to achieve the above-mentioned target, the application adopts the following technical scheme:

[0007] The aero-engine wave lobe mixer processing method comprises,

[0008] Step 1: blanking, cutting the plate into a fan-shaped raw material, and the outer circular arc end of the fan-shaped raw material contains a plurality of identical trapezoidal sawteeth, the number of the trapezoidal sawteeth is the same as the final number of wave lobes of the wave lobe mixer, and the bisector of each trapezoidal sawtooth passes through the center of the fan-shaped raw material;

[0009] Step 2: deburring, removing the burrs at the edge of the fan-shaped raw material;

[0010] Step 3: rounding, rounding the fan-shaped raw material so that the two radial edges of the fan-shaped raw material are close to each other and form a conical cylinder;

[0011] Step 4: welding, aligning and welding two radial edges of the conical cylinder-shaped material into a conical cylinder; at this time, the weld will be the only weld on the lobed mixer;

[0012] Step 5: heat treatment, removing welding stress of the conical cylinder;

[0013] Step 6: pre-expanding, loading the conical cylinder into the expander die in a vertical state along the axis and with the trapezoidal sawteeth facing downward, the pre-expanding including simultaneous inward shrinking forming of the outer side of the conical cylinder and outward expanding forming of the inner side of the conical cylinder, aligning the expander die with the grooves between the two trapezoidal sawteeth on the conical cylinder as positioning reference, and then starting the pre-expanding, the expander die being not closed during the pre-expanding, the not closed being relative to the expander forming in Step 9, for example, assuming that the travel of the expander die when closed is 100%, the travel in the pre-expanding is 70%;

[0014] Step 7: heat treatment, removing forming stress of the pre-expanded conical cylinder;

[0015] Step 8: polishing, polishing surface defects at the corresponding lobed groove of the pre-expanded conical cylinder;

[0016] Step 9: expander forming, loading the pre-expanded conical cylinder after heat treatment and polishing into the expander die used in Step 6 and aligning, and then starting the expander forming with 100% travel;

[0017] Step 10: fluorescent inspection, performing fluorescent inspection on the formed surface of Step 9;

[0018] Step 11: cutting, cutting the excess size of the outer shape to obtain the lobed mixer meeting the size requirements.

[0019] Further, in Step 1, making a cross section through the axis of the lobed mixer and the center of the groove between two adjacent lobes, forming a trapezoid by connecting the small inner diameter end and the large inner diameter end of the cross section with a straight line, keeping the angles between the waist and the top side and the bottom side of the trapezoid unchanged, proportionally reducing the length of the top side and the length of the bottom side of the trapezoid, then extending the waist to both ends, connecting the end points of the extended waist to obtain a new trapezoid, and generating a frustum of cone with the waist of the new trapezoid as the generatrix, the size of the fan-shaped material after the frustum of cone is unfolded being the size of the outer shape of the fan-shaped material.

[0020] Further, in Step 1, the trapezoidal sawteeth are formed as follows:

[0021] The arc length of the outer arc end of the fan-shaped raw material is equally divided by N, and N+1 equally divided points are obtained, the value of N is equal to twice the final lobe number of the lobe mixer, a straight line segment L1 is established through each odd equally divided point and tangent to the outer arc end, a straight line segment L2 is established through each even equally divided point and tangent to the outer arc end, then the straight line segment L2 is moved along the line connecting the even equally divided point and the center of the fan-shaped raw material by a distance H, the moving direction is away from the center of the fan-shaped raw material, and the end points of adjacent straight line segments L1 and L2 are sequentially connected in a straight line to obtain N trapezoidal sawteeth.

[0022] Further, in step 2, burrs around the fan-shaped raw material are removed by using a file, and the edges and bottoms of the notches between the trapezoidal sawteeth are polished by using sandpaper.

[0023] Further, in step 3, the fan-shaped raw material is rolled and bent into a conical cylinder by using a three-axis rolling bed.

[0024] Further, in step 4, the two radial edges of the fan-shaped raw material are first polished, then positioned and welded, then argon arc welding is performed by using the filler wire method, then the welded joint is ground after the argon arc welding, and then the leakage of the welded joint is checked.

[0025] Further, in step 5, the welding stress of the conical cylinder is removed by keeping the temperature at 1120-1140°C for 6-10 min.

[0026] Further, in step 6, the conical cylinder is contracted inward from the outside and expanded outward from the inside by using a hydraulic machine as a driving source, and the downward stroke of the hydraulic machine is converted into the contraction stroke from the outside to the inside of the conical cylinder and the expansion stroke from the inside to the outside of the conical cylinder.

[0027] Further, in step 11, the lobe mixer is cut according to the position of the line by using a five-axis laser cutting machine, the lobe starting angle line is drawn by using a circumferential cross-section template, and the height line of the lobe mixer is drawn by using an axial cross-section template.

[0028] The aviation engine lobe mixer expansion die comprises,

[0029] The outer guide rails are distributed on the generatrix of the first conical surface according to equal central angle, and the large diameter end of the first conical surface faces upward.

[0030] The inner guide rails are distributed on the generatrix of the second conical surface according to equal central angle, the second conical surface is coaxial with the first conical surface and located inside the first conical surface, and the large diameter end of the second conical surface faces downward.

[0031] The outer expansion petals are slidably connected to the outer guide rail, and the outer expansion petals comprise a first expansion surface and a first sliding groove; the first expansion surface is used for the profile expansion of the outer surface of the wave-limb mixer, and the first sliding groove is a straight groove matched with the outer guide rail;

[0032] The inner expansion petals are slidably connected to the inner guide rail, and the inner expansion petals comprise a second expansion surface and a second sliding groove; the second expansion surface is used for the profile expansion of the inner surface of the wave-limb mixer, and the second sliding groove is a straight groove matched with the inner guide rail.

[0033] Compared with the prior art, the aviation engine wave-limb mixer processing method and the expansion die have the following characteristics:

[0034] (1) The entire wave-limb mixer forming process has only one welding seam;

[0035] (2) The expansion is used to realize the overall forming of the wave-limb mixer cylinder and the wave-limb;

[0036] (3) By adjusting the cutting parameters, the shape precision of the wave-limb mixer is ensured, and the labor efficiency is greatly improved;

[0037] (4) By controlling the shape of the blank, the trapezoidal serrations on the arc-shaped edge of the fan-shaped blank are used for expansion positioning, and the synchronous expansion and contraction is used to ensure the profile size and precision.

[0038] At present, the processing method has been used in the field, and the purpose of the application is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 is an axial view of the wave-limb mixer;

[0040] Figure 2 is Figure 1 is an A-A sectional view of the wave-limb mixer;

[0041] Figure 3 is an expanded view of the fan-shaped blank of the wave-limb mixer with trapezoidal serrations;

[0042] Figure 4 is a schematic view of a conical cylinder;

[0043] Figure 5 is a schematic view of an inner expansion petal;

[0044] Figure 6 is a schematic view of an outer expansion petal;

[0045] Figure 7 is a schematic view of an expansion die;

[0046] Figure 8 is a schematic view of the obtaining process of the fan-shaped blank;

[0047] In the figure, 1 - outer inflation lobe, 2 - inner inflation lobe, 3 - outer guide rail, 4 - inner guide rail. DETAILED DESCRIPTION

[0048] The application will be further described below 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 examples, without departing from the above technical ideas of the application, any modifications, substitutions and changes made according to the ordinary technical knowledge and conventional means, are included in the scope of the application.

[0049] As Figure 7 , an aero-engine lobe mixer inflation die includes an outer inflation lobe 1, an inner inflation lobe 2, an outer guide rail 3 and an inner guide rail 4.

[0050] The 24 outer guide rails 3 are fixed on the upper end face of the lower die plate in the form of equal central angle, and the outer guide rails 3 are distributed on the generatrix of the first conical surface, the large diameter end of the first conical surface faces upward, and the outer guide rail 3 is a T-shaped rail groove;

[0051] The 24 inner guide rails 4 are fixed on the upper end face of the lower die plate in the form of equal central angle, and the inner guide rails 4 are distributed on the generatrix of the second conical surface, the second conical surface is coaxial with the first conical surface and located inside the first conical surface, the large diameter end of the second conical surface faces downward, and the inner guide rail 4 is a rectangular rail groove, and a T-shaped guide rail is fixed in the rail groove by screws;

[0052] The 24 outer inflation lobes 1 are slidably connected to the outer guide rails 3, as Figure 6 , the outer inflation lobe 1 includes a first inflation surface and a first sliding groove, the first inflation surface is used for the profile inflation of the outer surface of the lobe mixer, the first sliding groove is a rectangular linear groove, a T-shaped sliding block is installed in the linear groove by screws, and the outer inflation lobe 1 is slidably matched with the T-shaped rail groove of the outer guide rail 3 through the T-shaped sliding block;

[0053] The 24 inner inflation lobes 2 are slidably connected to the inner guide rails 4, as Figure 5 , the inner inflation lobe 2 includes a second inflation surface and a second sliding groove, the second inflation surface is used for the profile inflation of the inner surface of the lobe mixer, the second sliding groove is a T-shaped linear groove, and the inner inflation lobe 2 is slidably matched with the T-shaped guide rail on the inner guide rail 4 through the T-shaped linear groove;

[0054] The lengths of the outer inflation lobe 1 and the inner inflation lobe 2 are equal (i.e. Figure 7 , the heights of the outer inflation lobe 1 and the inner inflation lobe 2 are equal), when the upper die plate is driven downward by the hydraulic machine, as Figure 7 , the outer inflation lobe 1 and the inner inflation lobe 2 located between the upper die plate and the lower die plate can complete the same downward stroke.

[0055] The method for processing an aero-engine lobe mixer using the above-mentioned lobe mixer bulging mold includes the following steps:

[0056] Step 1: Cutting the material. Cut the titanium alloy blank into a fan-shaped blank, such as... Figure 8 The process is demonstrated, including obtaining the trapezoidal cross-section, proportionally reducing and extending the waist of the trapezoid. The fan-shaped blank is a section along the part's cross-section (passing through the axis of the beam mixer and the center of the grooves of two adjacent beams). Figure 8 (The large diameter end and the small diameter end are connected to form a trapezoid in the middle left figure (dashed line). Then, the four sides of the trapezoid are reduced inward proportionally. The reduction of any one of the four sides is about 5 to 8 mm. The trapezoid is used as the axial section of the subsequent conical cylinder. The two waists of the trapezoid are extended about 20 mm to each end along the axial direction and then unfolded to obtain the fan-shaped raw material.

[0057] like Figure 3 The outer arc end of the fan-shaped material has 24 evenly distributed trapezoidal serrations, and the center bisector of each trapezoidal serration passes through the center of the fan-shaped material.

[0058] The formation process of the trapezoidal sawtooth is as follows: Since the final number of lobes in the lobe mixer is 24, the outer arc length of the fan-shaped blank is divided into 48 equal parts, resulting in 49 division points (e.g., Figure 3 As shown, due to Figure 4 The fan-shaped fabric was closed to form a conical cylinder, so... Figure 3 (The leftmost and rightmost division points of the fan-shaped fabric coincide, as shown in the example.) Figure 3 Let the leftmost dividing point be numbered 1. Number the dividing points sequentially to the right. For each odd-numbered dividing point, establish a straight line segment L1 tangent to the outer arc end. For each even-numbered dividing point, establish a straight line segment L2 tangent to the outer arc end. Then, move line segment L2 a distance H along the line connecting the even-numbered dividing point and the center of the fan-shaped material, moving away from the center of the fan-shaped material. Connect the endpoints of adjacent line segments L1 and L2 sequentially using straight lines, with each line transitioning to the endpoints of adjacent line segments L1 and L2 using an arc of length R. This results in 24 trapezoidal sawtooths. Figure 4 .

[0059] like Figure 4 The value of distance H needs to be considered. Figure 2 The tail length h of the mid-lobe, the lobe length, and the machining allowance; the value of the straight segment L1 is determined according to... Figure 1 The distance between adjacent lobes A ( Figure 1 The length of the waist of the fan-shaped fabric and the machining allowance are determined, and the value of L2 is based on the width B at the end of the lobe. Figure 1 The outer diameter of the circle where the lobe is located, the elongation length of the waist of the fan-shaped material, and the machining allowance are determined.

[0060] Step 2: deburring, removing burrs of the fan-shaped material edge; using a file to remove burrs of the fan-shaped material, polishing and rounding the edges of the inwardly recessed notched edges and bottoms of the trapezoidal serrations with sandpaper, and the surface roughness is not greater than Ra3.2;

[0061] Step 3: rounding, using a three-axis rolling bed to roll the fan-shaped material into a conical cylinder, such as Figure 4 ;

[0062] Step 4: welding, welding the conical material into a conical cylinder, such as Figure 4 Before welding, the welding end faces of the butt joint edges of the to-be-welded parts are polished, the two surfaces within a range of not less than 15 mm in width are polished, then an argon arc welding machine is used for positioning welding of the fan-shaped material, the welding gap at the butt joint is not greater than 0.1 mm, the misalignment is not greater than 0.1 mm, then an automatic argon arc welding machine is used for automatic argon arc welding with a filler wire method, to ensure that the fan-shaped material is fully penetrated and has no defects. After automatic argon arc welding, the weld is ground to ensure that the weld is not higher than the base body by not more than 0.25 mm, after welding, penetration inspection is performed, kerosene method penetration is used for 5 minutes, leakage is not allowed, the material strength at the welded part is not less than 90% of the base material strength, and the welded part is polished to be flush with the base body after welding;

[0063] Step 5: heat treatment, heat treatment temperature (1120-1140) ℃ for (6-10) min, to remove welding stress;

[0064] Step 6: pre-expansion, aligning the grooves between the trapezoidal serrations at the large-diameter end of the fan-shaped material with the forming surface grooves of the outer expansion petals 1 or the forming surface protrusions of the inner expansion petals 2 in the expansion die, or aligning the straight line segments L2 of the trapezoidal serrations with the forming surface protrusions of the outer expansion petals 1 or the forming surface grooves of the inner expansion petals 2, then the die is lowered to 70% of the height (equivalent to the outer expansion petals 1 and the inner expansion petals 2 being lowered to a distance of 50-60 mm from the die closing), stopping pressing, and taking out the pre-expanded conical cylinder. The power equipment for pre-expansion is a hydraulic machine with a tonnage of not less than 400 t, a combined expansion die of inner expansion (inner expansion petals 2) and outer contraction (outer expansion petals 1) is used for expansion, and after the trapezoidal serrations are ensured to be consistent with the concave-convex surfaces of the outer expansion petals 1 and the inner expansion petals 2, the hydraulic machine is started to press;

[0065] Step 7: heat treatment, heat treatment temperature (1120-1140) ℃ for (6-10) min, then air cooling, to remove forming stress;

[0066] Step 8: polishing, polishing the surface defects of the grooves after the lobed forming of the conical cylinder, grinding and rounding the groove defects of the pre-formed lobes, and ensuring that the surface roughness is not greater than Ra3.2;

[0067] Step 9: bulging forming, the pre-bulging completed conical cylinder is put into the bulging mold again, and pressing is performed by using a hydraulic machine, after the lobe surface of the conical cylinder is coincided with the mold surface and the concave and convex positions are aligned, the conical cylinder is pressed, the hydraulic machine is lowered to the closed mold of the outer bulging lobe 1 and the inner bulging lobe 2, the pressure of the hydraulic machine is about 100t, the pressing is stopped, the outer bulging lobe 1 and the inner bulging lobe 2 are ejected, and the conical cylinder is taken out;

[0068] Step 10: fluorescence inspection, fluorescence inspection is performed on the whole surface of the conical cylinder;

[0069] Step 11: cutting: cutting the outer shape of the conical cylinder to obtain the final lobe mixer shape. A five-axis laser cutting machine is used, the laser cutting machine has a rotating platform, the laser head has a telescopic function, the conical cylinder needs to be bulged by a clamp, the roundness is not greater than 1, the coaxiality of the conical cylinder and the rotating platform is not greater than 0.5. The three-dimensional model of the lobe mixer (such as Figure 1 and Figure 2 ) is established for cutting. In order to ensure that the laser can normally cut, the processing process is simulated, and the B and C axis angles of the laser cutting machine are adjusted, wherein the B axis is the turning direction of the Z axis, and the C axis is the swing of the laser head. The circumferential cross-section template is used to draw the lobe starting angle line, and the axial template is used to draw the lobe mixer height line, and the part is cut according to the position of the line.

[0070] The contents not described in detail in the specification of the present application are the prior art known to those skilled in the art. Although the above describes the specific embodiments of the present application in order to facilitate those skilled in the art to understand the present application, it should be clear that the present 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 present application defined and limited by the appended claims, and all the inventions utilizing the concept of the present application are included in the protection.

Claims

1. A method for manufacturing a beam mixer for an aero-engine, characterized in that: include, Step 1: Cutting the material, take the board and cut it into fan-shaped rough pieces, and the outer arc end of the fan-shaped rough pieces contains multiple identical trapezoidal saw teeth. The number of trapezoidal saw teeth is the same as the final number of lobes of the lobe mixer. The bisector of each trapezoidal saw tooth passes through the center of the fan-shaped rough piece. Step 2: Deburring, removing burrs from the edges of the fan-shaped fabric; Step 3: Rounding. Round the fan-shaped material so that the two radial edges of the fan-shaped material are close together and form a cone shape. Step 4: Welding. Align the two radial edges of the conical blank and weld them together to form a conical cylinder. Step 5: Heat treatment to remove welding stress from the conical cylinder; Step 6: Pre-expansion. The conical cylinder is placed into the expansion mold with its axis vertical and trapezoidal serrations facing downward. The pre-expansion includes the simultaneous inward shrinkage forming of the outer side of the conical cylinder and the outward expansion forming of the inner side of the conical cylinder. The groove between the two trapezoidal serrations on the conical cylinder is used as the positioning reference to align the expansion mold, and then the pre-expansion begins. During the pre-expansion, the expansion mold is not closed. Step 7: Heat treatment to remove the forming stress after the pre-expansion of the conical cylinder; Step 8: Polishing, removing surface defects at the corresponding lobe grooves after the pre-expansion of the conical cylinder; Step 9: Bulging and forming. Place the pre-bulged conical cylinder, which has been heat-treated and polished, back into the bulging mold used in Step 6 and align it. Then begin bulging and forming with 100% bulging stroke. Step 10: Fluorescence inspection, perform fluorescence inspection on the entire bulging surface from step 9; Step 11: Cutting. Cut off the excess dimensions of the shape to obtain a beam mixer that meets the size requirements; In step 1, a cross section is made through the axis of the beam mixer and the center of the groove between two adjacent beams. A trapezoid is formed by connecting the small inner diameter end and the large inner diameter end of the cross section with a straight line. The angle between the waist of the trapezoid and the base and top sides remains unchanged. The length of the top side and the length of the base side of the trapezoid are reduced proportionally. Then the waist of the trapezoid is extended to both ends. The endpoints of the extended waist are connected to obtain a new trapezoid. The waist of the new trapezoid is used as the generatrix to generate a frustum. The fan-shaped size of the unfolded frustum is the outer size of the fan-shaped fabric. In step 1, the formation process of the trapezoidal saw teeth is as follows: Divide the arc length of the outer arc end of the fan-shaped material into N equal parts and obtain N+1 equal division points. The value of N is equal to twice the final number of lobes of the lobe mixer. Establish a straight line segment L1 tangent to the outer arc end through each odd-numbered division point, and establish a straight line segment L2 tangent to the outer arc end through each even-numbered division point. Then move the straight line segment L2 a distance H along the line connecting the even-numbered division point and the center of the fan-shaped material. The direction of movement is away from the center of the fan-shaped material. Use straight lines to connect the endpoints of adjacent straight line segments L1 and L2 in sequence to obtain N trapezoidal sawtooths. The bulging molds in steps 6 and 9 include, The outer guide rail (3) is distributed along the generatrix of the first conical surface at equal central angles, with the large diameter end of the first conical surface facing upwards. Inner guide rail (4), multiple inner guide rails (4) are distributed on the generatrix of the second conical surface at equal center angles. The second conical surface is coaxial with the first conical surface and located inside the first conical surface. The large diameter end of the second conical surface faces downward. The outer expansion lobe (1) is slidably connected to the outer guide rail (3). The outer expansion lobe (1) includes a first expansion surface and a first sliding groove. The first expansion surface is used for the surface expansion of the outer surface of the beam mixer. The first sliding groove is a straight groove and matches the outer guide rail (3). The inner expansion lobe (2) has multiple inner expansion lobes (2) that are slidably connected on the inner guide rail (4). The inner expansion lobe (2) includes a second expansion surface and a second sliding groove. The second expansion surface is used for the expansion of the inner surface of the lobe mixer. The second sliding groove is a straight groove and matches the inner guide rail (4).

2. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 2, a file is used to remove the burrs around the fan-shaped material, and sandpaper is used to polish the edges and bottom of the grooves between the trapezoidal serrations.

3. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 3, a three-axis rolling mill is used to roll the fan-shaped material into a round shape and bend it into a conical shape.

4. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 4, the two radial edges of the fan-shaped material are first polished, then tack welding is performed, and then argon arc welding is performed using the filler wire method. After argon arc welding, the weld is ground and the leakage at the weld is checked.

5. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 5, the welding stress of the conical cylinder is removed by holding it at 1120-1140℃ for 6-10 minutes.

6. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 6, the inward shrinkage forming from the outer side of the conical cylinder and the outward expansion forming from the inner side of the conical cylinder are driven by a hydraulic press, which converts the downward stroke of the hydraulic press into a shrinkage stroke from the outer side of the conical cylinder and an expansion stroke from the inner side of the conical cylinder.

7. The method for processing an aero-engine lobe mixer according to claim 1, characterized in that: In step 11, a five-axis laser cutting machine is used to draw the starting angle line of the lobe using a circumferential section template and the height line of the lobe mixer using an axial section template. The lobe mixer is then cut according to the position of the drawn lines.

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