Laser composite manufacturing and processing method for gas turbine casing part

Abstract

The invention provides a laser composite manufacturing and processing method for a gas turbine case part. The laser composite manufacturing and processing method comprises the following steps: S1, preparation before process production; s2, mounting a substrate; s3, light spot adjustment; s4, calling a flange program; s5, preheating the substrate; s6, flange cladding machining is conducted; s7, calling a casing program; s8, carrying out cladding processing on the casing; s9, calling a test block processing program; s10, performing cladding processing on the test block; s11, inspection is carried out; s12, heat treatment; s13, cutting a test block; s14, inspection is carried out; s15, removing the substrate; s16, the part is polished; s17, roughly turning the small end; s18, turning a large end; s19, turning a small end; and S20, final inspection. According to the method, a laser composite additive manufacturing process method is adopted, the typical structure configuration forming path and process, tissue and mechanical properties, residual stress and macroscopic deformation are researched, the basic rule and process of forming are mastered, and the turbine case part manufacturing process and verification application research are completed.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine manufacturing technology, specifically relating to a laser composite manufacturing method for gas turbine casing components. Background Technology

[0002] The turbine casing is the main load-bearing component of a gas turbine and a key component forming the gas turbine's airflow passage; its structure and load conditions are extremely complex. The turbine load-bearing casing is a typical component among gas turbine casing parts, operating in a high-temperature, high-pressure environment with complex load conditions and susceptible to oxidation and corrosion. Structurally, the turbine load-bearing casing connects the combustion chamber casing, the low-pressure turbine guide vane, and the low-pressure turbine support ring casing. The quality of the turbine load-bearing casing structure directly affects the engine's aerodynamic performance, lifespan, and reliability. Currently, gas turbine casings are all forged. This paper discusses a design based on the structural characteristics and standards of a gas turbine casing, combined with laser additive and subtractive machining processes and performance parameters. Summary of the Invention

[0003] The purpose of this invention is to provide a laser composite manufacturing method for gas turbine casing components.

[0004] A laser composite manufacturing method for gas turbine casing components includes the following steps: S1, pre-production preparation; S2, mounting the substrate; S3, adjusting the laser spot; S4, calling the flange program; S5, preheating the substrate; S6, flange cladding; S7, calling the casing program; S8, casing cladding; S9, calling the test block processing program; S10, test block cladding; S11, inspection; S12, heat treatment; S13, cutting the test block; S14, inspection; S15, removing the substrate; S16, grinding the part; S17, rough machining the small end; S18, machining the large end; S19, machining the small end; S20, final inspection.

[0005] Furthermore, S1 includes pre-process preparation, including pre-processing inspection, installation of welding wire, substrate surface pretreatment, and program trial run; the substrate surface pretreatment includes polishing, grinding, and removing oxide layer from the substrate surface.

[0006] Furthermore, the mounting of the substrate in S2 includes placing the substrate on the turntable, fixing the substrate on the turntable using a six-point fixing method, and adjusting the position of the substrate while rotating the turntable so that the substrate gradually coincides with the rotation center of the turntable.

[0007] Furthermore, the S3 light spot adjustment includes turning on the laser generator and sending light; making the laser spot hit the substrate; and adjusting the focal length of the laser to make the laser spot diameter 10 mm.

[0008] Furthermore, the substrate preheating in S5 includes heating the substrate using a laser, with the laser power being the same as the laser power used when printing the parts.

[0009] Furthermore, the S12 heat treatment includes cleaning the part by wiping the surface of the part with a clean white silk cloth dipped in acetone to remove fingerprints and other dirt, stress-relieving annealing at a temperature of 760°±10° and holding for 1 to 1.5 hours; disassembly and assembly by removing the part and placing it on a transport vehicle after it has cooled to room temperature.

[0010] Furthermore, the S14 inspection includes sending the test block to a testing institution for metallographic inspection, room temperature tensile inspection and high temperature tensile inspection. The grain size after heat treatment reaches level 3; the room temperature mechanical properties Rm≥700MPa, A≥30%; and the high temperature mechanical properties at 800℃ Rm≥245MPa, A≥40%.

[0011] Further, step S15, removing the substrate, involves placing the heat-treated part with its large end facing upwards on the machine tool turntable, placing equal-height pads under the workpiece, checking the height of the part's base plate, checking 8 points around the circumference, adjusting the dimensions (the dimensional difference should not exceed 2mm), using chucks to support the inner hole of the part after adjustment, fixing the part, and then checking the runout of the outer circle of the substrate (the runout should not exceed 0.5). Finally, the bottom surface of the tooling substrate, the outer circle of the substrate, and the outer circle of the bottom flange are machined according to the drawing.

[0012] Furthermore, the S17 rough machining of the small end includes placing the part with the large end facing down and placing a level pad; checking the lower part of the outer circle of the flange and ensuring that the runout of the flange outer diameter and the upper end face of the flange is no more than 0.05 mm.

[0013] Furthermore, S18 and S19 involve machining the large end and the small end. Machining the large end includes placing the part with the large end facing up on the machine tool turntable, aligning the inner hole of the small end after placing a level pad under the workpiece, and ensuring the alignment runout is within 0.05. Machining the small end includes turning it over for alignment, and then machining the small end process chuck to the dimensions shown in the drawing.

[0014] The beneficial effects of this invention are as follows: This invention combines emerging additive manufacturing with traditional subtractive manufacturing, integrating computer-aided design, mechanics, CNC, and laser technologies, and applying them to the manufacturing of gas turbine casing components. It breaks through the geometric limitations of current large metal component processing, enabling the manufacturing of complex multi-structure geometries. Compared to traditional manufacturing, it has a higher material utilization rate, saving more than 50% of material costs. Furthermore, it eliminates the need for molds and complex tools, allowing for rapid forming directly through laser melting of metal, while simultaneously increasing production efficiency by 3-5 times. In terms of performance, the equivalent stress strength reserve of the turbine casing components produced by the new process meets strength design requirements, while also satisfying the feasibility of the component manufacturing process and the economy of materials. The tensile strength and yield strength at 800℃ are superior to those of traditionally manufactured forgings, exhibiting good oxidation resistance below 1000℃, stable microstructure over long-term use, and good cold forming and welding performance. This laser composite manufacturing method for gas turbine casing components is a novel comprehensive processing technology and a new breakthrough in the field of gas turbine manufacturing for large components such as turbine load-bearing casings. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the turbine casing structure of the present invention; Figure 2 The printing sequence of the laser cladding 3D printing channels for the turbine casing part of this invention is shown from the outside to the inside. Figure 3 This is a diagram showing the printing sequence of the laser cladding 3D printing tracks for the turbine casing part of this invention, from the inside out. Figure 4 This is a stress-relief annealing curve diagram for the turbine casing part of this invention. Detailed Implementation

[0016] The present invention will now be further described with reference to the accompanying drawings.

[0017] like Figures 1-4 As shown, a laser composite manufacturing method for gas turbine casing components includes the following steps: S1, Pre-production process preparation; Pre-production process preparation includes pre-processing inspection, installation of welding wire, pretreatment of substrate surface and trial run of program; Pre-processing inspection includes confirming that the laser welding wire equipment of the heavy-duty composite precision manufacturing machining center is in good condition; Among them, the laser generator, water chiller and equipment turntable are operating normally; Confirm that the connection between each gas cylinder and the gas supply pipe in the argon gas container is intact and the pressure gauge reading is normal. Pre-production preparation for process installation includes receiving welding wire. Install the HGH3039 welding wire (15KG / coil) in 1.2, ensuring it is not loose and is not misaligned; after the welding wire is installed, use the program to control the wire feeding test; confirm that the wire feeding system is operating normally.

[0018] Pre-processing of the substrate surface during pre-production includes polishing, grinding, and removing the oxide layer from the substrate surface; there is no limit to the amount of polishing and grinding removed until the oxide layer is completely removed; there should be no obvious pits on the substrate after polishing and grinding; after polishing, the substrate is sanded with sandpaper, and the smoothness should not exceed Ra3.2; after sanding, the substrate surface is wiped with a cleaning cloth dipped in alcohol to remove residual particles from the substrate surface after sanding; multiple wipes can be made until there are no dirt marks on the cleaning cloth; The pre-production process includes trial operation of the programmed procedure without light supply, and observation of whether the linkage between the robot and the turntable is normal.

[0019] S2, Installing the substrate; Installing the substrate includes placing the substrate on the turntable and fixing the substrate to the turntable using a six-point fixing method. While rotating the turntable, adjust the position of the substrate so that the substrate gradually coincides with the rotation center of the turntable.

[0020] S3, Spot adjustment; Spot adjustment includes turning on the laser generator and sending light; making the laser spot hit the substrate; adjusting the focal length of the laser so that the laser spot diameter is 10 mm; S4, Flange program call; Flange program call includes importing the prepared flange cladding program (name: FALAN, program number: 005) into the printing system; S5, Substrate preheating; Substrate preheating includes heating the substrate using a laser, and the laser power should be consistent with the laser power used when printing the parts; the substrate can be printed when heated to above 300°C; protective gas is introduced when heating the substrate to prevent excessive oxidation of the substrate during the preheating process; S6, Flange cladding processing; Flange cladding processing includes running the program to begin cladding processing of the flange workpiece; real-time monitoring of the molten pool status during processing, stopping the machine immediately for inspection if abnormal molten pool color is detected; monitoring the usage of the welding wire, replacing it promptly when there are less than 5 turns of welding wire; stopping the machine after flange processing is completed, and checking the workpiece for over-oxidation; if so, grinding is required after the part has completely cooled down, grinding until the oxide layer is completely removed, measuring the remaining thickness, and reprinting until the thickness meets the drawing requirements; if there is no over-oxidation, grinding can be skipped and proceed directly to the next step.

[0021] S7, Call the casing program; Calling the casing program includes importing the prepared casing cladding program (name: JIXIA, program number 006) into the printing system.

[0022] S8, Chassis cladding process; Chassis cladding process includes running the program to start the cladding process of the chassis workpiece; real-time monitoring of the molten pool status during processing, stopping the machine immediately for inspection if abnormal molten pool color is detected; monitoring the use of welding wire, replacing it promptly when there are less than 5 turns of welding wire; stopping the machine after the chassis processing is completed; checking the workpiece for over-oxidation after stopping the machine; if so, grinding is required after the part has completely cooled down, grinding until the oxide layer is completely removed, measuring the remaining height, and printing additional thickness until it meets the drawing requirements; if there is no over-oxidation, grinding can be skipped and the next step can be performed directly.

[0023] S9, call the test block processing program; calling the test block processing program includes importing the prepared test block cladding program (named SHIYANG, program number 007) into the printing system.

[0024] S10, Test block cladding processing; Test block cladding processing includes running the program to start the cladding processing of the test block; real-time monitoring of the molten pool status during processing, stopping the machine immediately for inspection if abnormal molten pool color is detected; monitoring the use of welding wire, replacing it promptly when there are less than 5 turns of welding wire; stopping the machine after the test block processing is completed; checking the workpiece for over-oxidation after stopping the machine; if so, grinding is required after the part has completely cooled down, grinding until the oxide layer is completely removed, measuring the remaining height, and supplementing the printing until the thickness meets the drawing requirements; if there is no over-oxidation, grinding can be skipped and proceed directly to the next step.

[0025] S11, Inspection; S12, Heat Treatment; Heat treatment includes cleaning the parts, wearing disposable rubber gloves and masks, and wiping the surface of the parts with a clean white silk cloth dipped in acetone to remove fingerprints and other dirt. Stress-relief annealing at 760°±10°C for 1 to 1.5 hours; disassembly and assembly: after the parts have cooled to room temperature, remove them and place them on a transport vehicle; visually inspect the appearance of the parts, ensuring the surface is free of scratches and other defects; the surface of the heat-treated parts should have a bright color, with permissible metallic luster and an oxide color ranging from pale yellow, but not extremely bright or densely pitted or otherwise oxide-colored. The heat treatment must be performed within 24 hours after printing and must not exceed this timeframe.

[0026] S13, Cutting the test block; Cutting the test block includes cutting the test block with an angle grinder, and the remaining thickness of the test block after cutting shall not be less than 35mm.

[0027] S14, Inspection; Inspection includes sending the test block to a testing institution for metallographic examination, room temperature tensile testing, and high temperature tensile testing. The grain size after heat treatment reaches grade 3; room temperature mechanical properties Rm≥700MPa, A≥30%; high temperature mechanical properties at 800℃ Rm≥245MPa, A≥40%.

[0028] S15, Remove the substrate; Removing the substrate includes placing the heat-treated part with the large end facing up on the machine tool turntable, placing equal-height pads under the workpiece, checking the height of the part's base plate, checking 8 points around the circumference, adjusting the dimensions as much as possible, and ensuring that the dimensional difference does not exceed 2mm. After adjusting the dimensions, use chucks to support the inner hole of the part; After fixing the part, check the runout of the outer circle of the substrate, and ensure that the runout does not exceed 0.5; and machine the bottom surface of the tooling substrate, the outer circle of the substrate, and the outer circle of the bottom flange according to the drawing.

[0029] S16, Part Grinding; Part grinding includes grinding the inner and outer surfaces of the workpiece after laser cladding. This removes weld beads and weld inclusions.

[0030] S17, rough machining of the small end; rough machining of the small end includes placing the part with the large end facing down and placing a level pad; checking the lower part of the outer circle of the flange, ensuring that the runout of the flange outer diameter and the upper end face of the flange is not greater than 0.05 mm, and machining all dimensions (small end face of the casing, machining the inner and outer walls of the casing).

[0031] S18, Machining the large end; Machining the large end involves placing the part with its large end facing upwards on the machine tool turntable, placing a level shim under the workpiece, and then aligning the inner hole of the small end. The alignment runout should be within 0.05. Dimensions for machining the large end. S19, Machining the small end; Machining the small end process chuck includes flipping and alignment, and after alignment, machining the small end process chuck to the dimensions shown in the drawing. S20, Final Inspection; Final inspection includes checking and recording all machined dimensions of the workpiece.

[0032] Figure 1 The diagram shows a schematic of a turbine casing for a gas turbine. It is an integrally formed conical cylindrical structure with a rear flange at the bottom. This structure provides a cooling chamber for the turbine cooling blades and ensures a smooth flow path for the high-temperature gas. It is made of GH3039, a high-temperature alloy with a low coefficient of thermal expansion. Its chemical composition (mass percentage) is: C≤0.08, Cr: 19.00~22.00, Mo: 1.8~2.30, Ti: 0.35~0.75, Nb: 0.90~1.30, Al: 0.35~0.75, Fe≤3.00, Si≤0.80, Mn≤0.40, P≤0.020, S≤0.012, Cu≤0.20, Ni: balance. The workpiece is formed by laser printing of the bottom flange and the conical cylindrical casing.

[0033] The trial run of the S1 program includes the study of laser cladding part forming process scheme and process parameters, as shown in Figure 2. Figure 3Two sequences for laser cladding 3D printing were proposed: outside-to-in and inside-to-out. Testing showed that the inside-to-in sequence resulted in insufficient inner run width, which decreased with increasing height. Therefore, the inside-to-out sequence was chosen for its better performance. The laser cladding process parameters, after testing and optimization, were determined to be: laser power 5000W, filament feed speed 25mm / s, scanning speed 1mm / s, layer height 1mm, height increment 1mm, single run width 5mm, overlap rate 18%, and inward translation 0.6mm. These process parameters were applied in programs S4, S7, and S9.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser composite manufacturing method for gas turbine casing components, characterized in that, The process includes the following steps: S1, pre-production preparation; S2, mounting the substrate; S3, spot adjustment; S4, flange program call; S5, substrate preheating; S6, flange cladding; S7, calling the casing program; S8, casing cladding; S9, calling the test block processing program; S10, test block cladding; S11, inspection; S12, heat treatment; S13, cutting the test block; S14, inspection; S15, removing the substrate; S16, part grinding; S17, rough machining the small end; S18, machining the large end; S19, machining the small end; S20, final inspection.

2. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, S1 includes pre-process preparation, including pre-processing inspection, installation of welding wire, substrate surface pretreatment, and program trial operation; the substrate surface pretreatment includes polishing, grinding, and removing oxide layer from the substrate surface.

3. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The step S2 of mounting the substrate includes placing the substrate on the turntable, fixing the substrate on the turntable using a six-point fixing method, and adjusting the position of the substrate while rotating the turntable so that the substrate gradually coincides with the rotation center of the turntable.

4. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The S3 spot adjustment includes turning on the laser generator and sending light; making the laser spot hit the substrate; and adjusting the focal length of the laser to make the laser spot diameter 10 mm.

5. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The substrate preheating in S5 includes heating the substrate using a laser, with the laser power being the same as that used when printing the parts.

6. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The S12 heat treatment includes cleaning the parts by wiping the surface of the parts with a clean white silk cloth dipped in acetone to remove fingerprints and other dirt, stress-relieving annealing at a temperature of 760°±10° and holding for 1 to 1.5 hours, and disassembly and assembly by removing the parts and placing them on a transport vehicle after they have cooled to room temperature.

7. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The S14 test includes sending the test block to a testing institution for metallographic examination, room temperature tensile test and high temperature tensile test. The grain size after heat treatment reaches level 3; the room temperature mechanical properties Rm≥700MPa, A≥30%; and the high temperature mechanical properties at 800℃ Rm≥245MPa, A≥40%.

8. The laser composite manufacturing method for gas turbine casing parts according to claim 1, characterized in that, The S15 substrate removal process includes placing the heat-treated part with its large end facing upwards on the machine tool turntable, placing equal-height pads under the workpiece, checking the height of the part's base plate, checking 8 points around the circumference, adjusting the dimensions to ensure the dimensional difference is no greater than 2mm, using chucks to support the inner hole of the part after adjusting the dimensions, fixing the part, and then checking the runout of the outer circle of the substrate to ensure the runout is no greater than 0.5mm; and machining the bottom surface of the tooling substrate, the outer circle of the substrate, and the outer circle of the bottom flange according to the drawing.

9. The laser composite manufacturing method for gas turbine casing components according to claim 1, characterized in that, The S17 rough machining of the small end includes placing the part with the large end facing down and placing a level pad; checking the lower part of the outer circle of the flange and ensuring that the runout of the flange outer diameter and the upper end face of the flange is no more than 0.05 mm.

10. The laser composite manufacturing method for gas turbine casing parts according to claim 1, characterized in that, S18 and S19 involve machining the large end and the small end. Machining the large end includes placing the part with the large end facing up on the machine tool turntable, aligning the inner hole of the small end after placing a level pad under the workpiece, and ensuring the alignment runout is within 0.

05. Machining the small end includes turning it over for alignment, and then machining the small end process chuck to the dimensions shown in the drawing.

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