Efficient grid reinforcing rib structure expansion adjusting sheet composite additive manufacturing method

Abstract

The invention relates to an efficient grid reinforcing rib structure expansion adjusting sheet composite additive manufacturing method. The method comprises the following steps of part analysis, part blank state design, part forming, heat treatment, rough machining, heat treatment and finish machining. According to the method, advantages and disadvantages of composite manufacturing and laser fused deposition additive manufacturing in connection performance, process matching performance and processing efficiency are fully utilized, the expansion adjusting sheet of the grid reinforcing rib structure is manufactured by adopting a composite manufacturing and laser fused deposition additive manufacturing method, and macro and microstructure is optimized through a heat treatment process; the scanning strategy is optimized, heat accumulation of each layer of forming area is reduced, the forming strength of the part is guaranteed, the deformation amount is reduced, the part machining technology is improved, and the part rejection rate is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of metal additive manufacturing of aircraft engine parts, and in particular to a composite additive manufacturing method for an expansion regulating piece of a high-efficiency grid reinforcement rib structure. Background Art

[0002] The expansion adjustment plate part is a key component in the aircraft engine. It is a typical "web + grid reinforcement" structure. The material is TA15 titanium alloy. The product consists of a web, grid reinforcement, and assembly hole surface. The maximum outline is about 900×300×50mm, the web thickness is about 2mm, and the minimum wall thickness of the reinforcement is about 3mm. According to the existing structure of the part, considering the outline size, production cost, processing cycle, and precision requirements, the existing structure is suitable for manufacturing using the LaserMelt Deposition (LMD) process in the additive manufacturing process. Analysis of the expansion adjustment plate structure shows that the bottom web is a large-area plate-like structure. If it is all manufactured using the laser melting deposition process, the manufacturing cycle will be long. In order to further improve manufacturing efficiency, the bottom web is made of a titanium alloy substrate, and then mechanical processing is used to remove a small amount of excess.

[0003] The laser melting deposition process is a non-steady-state variable temperature cycle process of extremely rapid metal heating-melting metallurgy-cooling and solidification. It uses high-energy laser as the heat source, and pre-set or synchronously supplied metal powder or metal wire as the forming material. According to the scanning path planned by the layered slicing information of the part model, metal powder is deposited on the metal substrate, and the metal powder is melted, rapidly solidified, and deposited layer by layer through a high-energy laser beam. At present, the comprehensive performance of the formed parts by the laser melting deposition process is close to that of forgings.

[0004] TA15 titanium alloy, with a nominal composition of Ti-6Al-2Zr-1Mo-1V, is a near-α-type titanium alloy with good comprehensive properties. It has moderate room temperature and high temperature strength, good thermal stability and welding performance. It is mainly used for aircraft engine parts in working environments below 500°C. Its microstructure includes lamellar structure, strip structure, equiaxed structure, and mixed dual-state structure, etc. The mechanical properties are usually improved by improving the microstructure. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a high-efficiency grid reinforcement rib structure expansion adjustment plate composite additive manufacturing method; the specific technical scheme is as follows:

[0006] A high-efficiency grid reinforcement rib structure expansion adjustment sheet composite additive manufacturing method comprises the following steps:

[0007] Step 1: Parts Analysis

[0008] Analyzing the composition of the parts, the parts are composed of a web, grid reinforcement ribs, and assembly hole surfaces. The maximum outline is about 900×300×50mm, the web thickness is about 2mm, and the minimum wall thickness of the reinforcement ribs is about 3mm; the bottom web is a large-area plate-like structure;

[0009] Step 2: Part blank state design

[0010] The blank design of the product is to add the allowance on the basis of the precision digital model; all the holes in the assembly hole surface are filled and sealed, and all the structures in the expansion adjustment piece that are not connected to the bottom of the part are added with solid support to prevent collapse during the forming process;

[0011] Step 3: Part Forming

[0012] The expansion adjustment piece blank is manufactured according to the designed part blank state;

[0013] Step 4: Heat treatment

[0014] The parts are subjected to stress relief annealing at a heating temperature of 640±10℃ and a holding time of 2h±15min, followed by air cooling after being taken out of the furnace;

[0015] Step 5: Rough machining

[0016] Rough machining is performed on the part blank after stress relief annealing to ensure that the flatness is less than 0.2mm, and a small amount of margin is left for subsequent fine machining;

[0017] Step 6: Heat treatment

[0018] Double annealing is performed on the blank parts, with the heating temperature of 840±10℃, keeping temperature for 2h±15min, and air cooling after being taken out of the furnace; 700±10℃, keeping temperature for 2h±15min, and air cooling after being taken out of the furnace;

[0019] Step 7: Finishing

[0020] Finishing is divided into primary finishing, secondary finishing and tertiary finishing.

[0021] The preferred embodiment of the composite additive manufacturing method for an efficient grid reinforcement structure expansion adjustment plate is that, in step 2, a margin of 3 mm to 6 mm is left on the outside of the blank body of the part.

[0022] The described method for high-efficiency composite additive manufacturing of expansion regulating plates with grid reinforcement rib structure has a preferred embodiment that, in step 2, in combination with the large size of the expansion regulating plate parts, a substrate mixed manufacturing method is proposed to be used for deposition manufacturing, and the entire structure of the web of the expansion regulating plate blank and part of the grid reinforcement ribs 3 and the assembly hole surface 4 structure are sunk into a 20 mm thick TA15 titanium alloy substrate, so that the TA15 titanium alloy substrate becomes a part of the expansion regulating plate blank, and the exposed part of the TA15 titanium alloy substrate is formed by laser melting deposition manufacturing.

[0023] The preferred embodiment of the composite additive manufacturing method for an efficient grid reinforcement rib structure expansion adjustment plate is that, in step three, the scanning strategy during the manufacturing process of the expansion adjustment plate blank adopts bow-shaped partition scanning.

[0024] The described method for high-efficiency composite additive manufacturing of an expansion adjustment plate of a grid reinforcement rib structure has a preferred embodiment that, in step seven, a first finishing operation is performed to remove 1.5 mm of excess to ensure a flatness of 0.1 mm and a roughness of Ra 3.2 μm after processing; a second finishing operation is performed to process the through holes on the assembly hole surface; and a third finishing operation is performed to finish all dimensions to the final dimensions.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] The present invention makes full use of the advantages and disadvantages of composite manufacturing and laser melt deposition additive manufacturing in connection performance, process matching and processing efficiency, adopts the method of composite manufacturing and laser melt deposition additive manufacturing to manufacture grid reinforcement rib structure expansion adjustment pieces, and optimizes the macro and micro structures through heat treatment process, which not only ensures the forming strength of the parts and reduces the deformation, but also improves the parts processing technology and reduces the parts scrap rate, thereby realizing low-cost, high-efficiency, low-residue and high-quality manufacturing of grid reinforcement rib structure expansion adjustment pieces, breaking the concept of traditional "subtractive manufacturing" mechanical processing methods for parts, and developing an efficient composite additive manufacturing method for grid reinforcement rib structure expansion adjustment pieces, which makes full use of the advantages of the two advanced processing methods of composite manufacturing and laser melt deposition additive manufacturing to form complementary improvements, and combines the heat treatment process with the laser melt deposition deformation control method to reduce the difficulty of manufacturing technology and the risk of scrap, and also reduces the difficulty and cost of blank manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the expansion adjustment piece of the grid reinforcement rib structure involved in the present invention;

[0028] Figure 2 It is a schematic diagram of the composite manufacturing process of the expansion adjustment piece of the grid reinforcement rib structure involved in the present invention;

[0029] Figure 3It is a schematic diagram of the partition scanning path of the laser melting deposition involved in the present invention.

[0030] In the figure: 1-expansion adjustment plate, 2-web, 3-grid reinforcement rib, 4-assembly hole surface, 5-outer position of the main body surface, 6-height direction position, 7-inner position, 8-expansion adjustment plate blank, 9-TA15 titanium alloy substrate. DETAILED DESCRIPTION

[0031] The following is combined with Figure 1-3 The present invention is described in detail, but the protection scope of the present invention is not limited by the accompanying drawings.

[0032] A high-efficiency grid reinforcement rib structure expansion adjustment plate composite additive manufacturing method, the method comprising the following steps:

[0033] The overall steps are: part analysis - part blank state design - part forming - heat treatment - rough machining - heat treatment - finishing.

[0034] Step 1: Parts Analysis

[0035] Expansion adjustment piece 1 Figure 1 As shown, it consists of a web 2, a grid reinforcement rib 3, and an assembly hole surface 4. The maximum outer contour of the part is about 900×300×50mm, the web thickness is about 2mm, and the minimum wall thickness of the grid reinforcement rib is about 3mm; the bottom web is a large-area plate-like structure.

[0036] Step 2: Part blank state design

[0037] The blank design of the product is to add allowance on the basis of the precision digital model. An allowance of 4mm is added to the outer position 5 of the main surface of the expansion adjustment piece 1 to avoid shrinkage during the printing process of the part; an allowance of 6mm is added to the height direction position 6 of the expansion adjustment piece 1 to avoid the problem of missing due to unevenness in the height direction; an allowance of 3mm is added to the inner position 7 of the expansion adjustment piece 1 to avoid shrinkage during the printing process of the part. The holes in the assembly hole surface 4 are all filled and sealed, and all structures in the expansion adjustment piece 1 that are not connected to the bottom of the part are added with solid support to prevent collapse during the forming process. The web 2 structure at the bottom of the expansion adjustment piece blank 8 is relatively large in size. During the forming process, due to the concentration of thermal stress, warping and deformation will occur. Combined with the structural characteristics of the part, the substrate mixed manufacturing method is used for additive manufacturing. The entire structure of the web 2 and part of the grid reinforcement ribs 3 and the assembly hole surface 4 structure in the expansion adjustment piece blank 8 are sunk into a 20mm thick TA15 titanium alloy substrate 9, and finally the expansion adjustment piece blank 8 is generated. Figure 2 As shown, the TA15 titanium alloy substrate 9 becomes a part of the final product of the expansion regulating piece 1, and the exposed portion of the TA15 titanium alloy substrate 9 is formed by laser melting deposition.

[0038] Step 3: Part Forming

[0039] The expansion adjustment sheet blank 8 is manufactured according to the blank state shown in step S2. The scanning strategy adopts a bow-shaped partition scanning, such as Figure 3 The scanning sequence is area a - area d - area c - area b. The black mark point is the starting point of the laser scanning position of each area. The laser scanning is performed in the direction indicated by the arrow.

[0040] Step 4: Heat treatment

[0041] The expansion regulating plate blank 8 is subjected to stress relief annealing: the heating temperature is 640±10°C, the holding time is 2h±15min, and the blank is air-cooled after being taken out of the furnace.

[0042] Step 5: Rough machining

[0043] The expansion adjustment plate blank 8 after heat treatment is rough-machined to ensure that the flatness is less than 0.2 mm, and a small margin of 2 mm is left for subsequent fine machining.

[0044] Step 6: Heat treatment

[0045] Double annealing of the expansion adjustment plate blank 8:

[0046] (1) Heating temperature is 840±10℃, keeping temperature for 2h±15min, and air cooling after exiting the furnace;

[0047] (2) The heating temperature is 700±10℃, the temperature is kept for 2h±15min, and then air-cooled after being taken out of the furnace.

[0048] Step 7: Finishing

[0049] The expansion adjustment piece blank 8 is subjected to primary finishing, secondary finishing and tertiary finishing respectively.

[0050] One of the finishing operations removes 1.5mm of excess to ensure a flatness of 0.1mm and a roughness of Ra3.2μm after processing.

[0051] Secondary finishing: machining the through hole on assembly hole surface 4.

[0052] Three finishing operations are performed to finish all dimensions to the final dimensions, meeting the dimensional requirements of the expansion adjustment piece 1 part.

[0053] The above embodiments are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the protection scope determined by the claims of the present invention.

Claims

1. A high-efficiency grid reinforcement rib structure expansion adjustment sheet composite additive manufacturing method, characterized in that: The steps include: Step 1: Parts Analysis Analyzing the composition of the parts, the parts are composed of a web, grid reinforcement ribs, and assembly hole surfaces. The maximum outline is 900×300×50mm, the web thickness is about 2mm, and the minimum wall thickness of the reinforcement ribs is 3mm; the bottom web is a large-area plate-like structure; Step 2: Part blank state design The blank design of the product is to add the allowance on the basis of the precision digital model; all the holes in the assembly hole surface are filled and sealed, and all the structures in the expansion adjustment piece that are not connected to the bottom of the part are added with solid support to prevent collapse during the forming process; Step 3: Part Forming The expansion adjustment piece blank is manufactured according to the designed part blank state; Step 4: Heat treatment The parts are subjected to stress relief annealing at a heating temperature of 640±10℃ and a holding time of 2h±15min, followed by air cooling after being taken out of the furnace; Step 5: Rough machining Rough machining is performed on the part blank after stress relief annealing to ensure that the flatness is less than 0.2mm, and a small amount of margin is left for subsequent fine machining; Step 6: Heat treatment Double annealing is performed on the blank parts, with the heating temperature of 840±10℃, keeping temperature for 2h±15min, and air cooling after being taken out of the furnace; 700±10℃, keeping temperature for 2h±15min, and air cooling after being taken out of the furnace; Step 7: Finishing Finishing is divided into primary finishing, secondary finishing and tertiary finishing.

2. A high-efficiency grid reinforcement rib structure expansion adjustment sheet composite additive manufacturing method according to claim 1, characterized in that: In step 2, a margin of 3 mm to 6 mm is left on the outside of the main body of the blank of the part.

3. The method for composite additive manufacturing of an efficient grid reinforcement rib structure expansion adjustment sheet according to claim 1, characterized in that: In step two, considering the large size of the expansion adjustment piece parts, it is planned to adopt a substrate mixed manufacturing method for deposition manufacturing, and the entire structure of the web of the expansion adjustment piece blank and part of the grid reinforcement ribs 3 and the assembly hole surface 4 structure are sunk into a 20 mm thick TA15 titanium alloy substrate, so that the TA15 titanium alloy substrate becomes a part of the expansion adjustment piece blank, and the exposed part of the TA15 titanium alloy substrate is formed by laser melting deposition manufacturing.

4. The method for composite additive manufacturing of an efficient grid reinforcement rib structure expansion adjustment sheet according to claim 1, characterized in that: In step three, the scanning strategy during the manufacturing process of the expansion adjustment plate blank adopts bow-shaped partition scanning.

5. The method for composite additive manufacturing of an efficient grid reinforcement rib structure expansion adjustment sheet according to claim 1, characterized in that: In step seven, the first finishing is to remove 1.5mm of excess to ensure the flatness of 0.1mm and the roughness of Ra3.2μm after processing; the second finishing is to process the through holes on the assembly hole surface; the third finishing is to finish all dimensions to the final size.

Images