High-strength and large-length-diameter-ratio combustion chamber shell and manufacturing process thereof

Abstract

The invention belongs to the technical field of solid engines, and particularly discloses a high-strength large-length-diameter-ratio combustion chamber shell and a manufacturing process thereof. The high-strength combustion chamber shell with the large length-diameter ratio comprises a front end socket, a barrel I, a barrel II and a rear end socket which are coaxially arranged. The front end socket is welded at the front end of the cylinder I, the rear end of the cylinder I is welded with the front end of the cylinder II, and the rear end socket is welded at the rear end of the cylinder II; internal threads are arranged on the side wall of an inner hole in the front of the front end socket; an external thread is arranged on the excircle of the front part of the front sealing head; a plurality of threaded holes are formed in the rear end face of the rear end socket and evenly distributed in the circumferential direction. The high-strength combustion chamber shell with the large length-diameter ratio has the advantages of being simple in structure, light, consistent in outer diameter, large in length-diameter ratio, small in mass and the like, and the negative mass of a solid engine can be effectively reduced. According to the high-strength combustion chamber shell with the large length-diameter ratio, the process of heat treatment and finish machining is conducted after segmented welding forming, and the product quality consistency and reliability are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of solid motors, and in particular relates to a high-strength and large aspect ratio combustion chamber casing and a manufacturing process thereof. Background Art

[0002] Solid rocket engines are one of the most important parts of aircraft. The combustion chamber shell provides a place for the storage and combustion of propellant. At the same time, the combustion chamber shell is also part of the overall structure of the aircraft. Many parts on the aircraft are connected to it, and it also has to bear other mechanical loads. When the engine is working, the propellant burns in the combustion chamber shell, and the high-temperature and high-pressure combustion gas generated is ejected from the nozzle to provide power for the aircraft. The combustion chamber shell is an important part of the solid rocket engine, and its main structure is a long cylinder.

[0003] With the rapid development of aircraft, the overall requirements for power devices of aircraft are getting higher and higher. It is necessary to use a high-strength and light-weight combustion chamber shell to reduce the passive mass of the aircraft. Usually, the negative mass of the aircraft is reduced by reducing the wall thickness. At present, the combustion chamber shell with a diameter of 300 mm and an aspect ratio greater than 15 is processed in sections and then assembled by mechanical connection. This processing method makes the combustion chamber shell easy to deform. If the shell deformation is reduced by increasing the wall thickness (thickness above 2.7 mm), the processing technology is too complicated and cannot meet the requirements during implementation. The combustion chamber shell manufactured by the mechanical manufacturing process of the above two methods is of large mass and cannot meet the requirements of low passive mass of the aircraft. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-strength, high-aspect-ratio combustion chamber casing and a manufacturing process thereof which is simple in structure, lightweight, easy to manufacture, and can meet the requirements of the aircraft for negative mass.

[0005] The technical solution adopted by the present invention is: a high-strength and large aspect ratio combustion chamber casing, comprising a front head, a cylinder body I, a cylinder body II and a rear head; the front head is welded to the front end of the cylinder body I, the rear end of the cylinder body I is welded to the front end of the cylinder body II, and the rear head is welded to the rear end of the cylinder body II; the front head, the cylinder body I, the cylinder body II and the rear head are coaxial; An internal thread connected to the ignition device is provided on the side wall of the inner hole of the front head; an external thread provided on the outer circle of the front head is used to connect with the aircraft; A plurality of threaded holes are arranged on the rear end surface of the rear head, and the plurality of threaded holes are evenly arranged along the circumferential direction for connecting the engine nozzle.

[0006] In the above-mentioned high-strength and large aspect ratio combustion chamber casing, the wall thickness of cylinder I and cylinder II are both 2 mm.

[0007] In the above-mentioned high-strength and large aspect ratio combustion chamber casing, a centering portion is respectively provided on the outer circle of the front head, cylinder body I, cylinder body II and rear head, and the diameter of the centering portion is 300 mm.

[0008] A manufacturing process for a high-strength and large-length-diameter-ratio combustion chamber casing is used to manufacture the above-mentioned high-strength and large-length-diameter-ratio combustion chamber casing, comprising the following steps: 1) Processing the front head, cylinder I, cylinder II and rear head; 2) Weld the front head and cylinder I; The welding is carried out by a thin-walled shell welding tool, which includes a mandrel, an expansion cone, a pressure plate I and a pressure plate II. External threads are respectively provided at both ends of the mandrel, and an expansion cone is fixedly installed on the mandrel. The expansion cone is coaxial with the mandrel. A plurality of expansion blocks are mounted on the side of the expansion cone. The plurality of expansion blocks form an annular structure. The inner hole of the annular structure cooperates with the expansion cone. A copper plate is provided on the outer surface of the expansion block. One end face of the expansion block contacts one end of a gland. The gland is sleeved on the mandrel and arranged close to the small end of the expansion cone. The other end of the gland contacts the gland nut. The gland nut is threaded with the mandrel. Pressure plates I and II are sleeved on the mandrel and positioned by pressure plate nut I and pressure plate nut II respectively. Pressure plate I is used to position the front head or the rear head, and pressure plate II is used to position the cylinder I or the cylinder II. First, insert the mandrel and the expansion block and gland sleeved on the mandrel into the center hole of the front head and cylinder body I, and adjust the mandrel so that the expansion block is located at the gap between the front head and the cylinder body I at the opposite ends; adjust the gland nut so that the outer side of the expansion block presses against the inner wall of the front head and cylinder body I; set the pressure plate I at the center hole of the end of the front head facing away from the cylinder body I and fix it through the pressure plate nut I, set the pressure plate II at the center hole of the end of the cylinder body I facing away from the front head and fix it through the pressure plate nut II, and adjust the gap between the front head and cylinder body I to 2-5mm by tightening the pressure plate nut I and the pressure plate nut II; then turn on the welding machine to weld the front head and cylinder body I; 3) Welding of cylinder I and cylinder II Remove the pressing plate I and II, and loosen the gland nut; put the cylinder II on the outside of the mandrel so that the cylinder II is set close to the cylinder I, and adjust the mandrel so that the expansion block is located at the gap between the opposite ends of the cylinder I and the cylinder II; adjust the gland nut so that the outer side of the expansion block presses against the inner wall of the cylinder I and the cylinder II; set the pressing plate I at the center hole of the end of the front head facing away from the cylinder II and fix it through the pressing plate nut I, set the pressing plate II at the center hole of the end of the cylinder II facing away from the front head and fix it through the pressing plate nut II, and adjust the gap between the front cylinder II and the cylinder I to 2-5mm by tightening the pressing plate nut I and the pressing plate nut II; then turn on the welding machine to weld the cylinder II and the cylinder I; 4) Welding of cylinder II and rear head Remove the pressure plate I and pressure plate II, and loosen the gland nut; put the rear head on the outside of the core shaft so that the rear head is set close to the cylinder II; and adjust the core shaft so that the expansion block is located in the gap between the cylinder II and the rear head; adjust the gland nut so that the outer side of the expansion block presses against the inner wall of the rear head and the cylinder II; set the pressure plate I at the center hole of the end of the front head facing away from the cylinder II and fix it through the pressure plate nut I, set the other pressure plate I at the center hole of the end of the rear head facing away from the front head and fix it through another pressure plate nut I, and adjust the distance between the two pressure plates I by tightening the two pressure plate nuts I so that the gap between the head and the cylinder II is 2-5mm; then turn on the welding machine to weld the cylinder II and the rear head to form the combustion chamber shell; 5) Remove the welding tooling of the thin-walled shell and perform non-destructive testing on the welds; if there are unqualified welds, perform repair welding on the unqualified welds; after the welds are qualified, perform envelope circle testing on the combustion chamber shell and perform tempering treatment on the combustion chamber shell; at the same time, correct the shape of the combustion chamber shell; 6) Grind the weld, tap the multiple threaded holes of the rear head, and remove burrs and rust from the outer surface of the combustion chamber shell; then rough bore the inner cavity of the combustion chamber shell, perform a water pressure test on the combustion chamber shell, perform non-destructive testing on the weld again after the water pressure test, turn the external and internal threads of the front head; fine bore the inner cavity of the combustion chamber shell, remove burrs from the inner cavity of the combustion chamber shell, inspect, and put the qualified products into storage.

[0009] In the manufacturing process of the high-strength and large aspect ratio combustion chamber shell, argon arc welding is used for welding in steps 2)-4), and the welded parts are preheated before welding, and the preheating temperature of the welded parts is 200°C; the welding power is 2.5kW, the welding speed is 1.8m / min, the spot diameter is 0.4mm, and the defocus is -0.2mm.

[0010] In the above-mentioned manufacturing process of the high-strength and large aspect ratio combustion chamber casing, in steps 5) and 6), X-ray detection and / or fluorescent flaw detection are used to perform non-destructive testing on the weld.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1) The high-strength and large aspect ratio combustion chamber casing of the present invention has the advantages of simple structure, light weight, consistent outer diameter, large aspect ratio, small mass, etc., which can effectively reduce the negative mass of the solid engine. The high-strength and large aspect ratio combustion chamber casing of the present invention is formed by segmented welding, heat treatment, and then fine processing, which improves the quality consistency and reliability.

[0012] 2) In the manufacturing process of the present invention, the combustion chamber shell is welded by argon arc ring welding, and the weld is tightened by expansion blocks during welding to facilitate disassembly; and the coaxiality and misalignment of the welded parts are ensured to be less than 0.2mm, ensuring the consistency of quality.

[0013] 3) The invented manufacturing process uses argon arc girth welding to weld the combustion chamber shell instead of the commonly used roll welding, which reduces product deformation, shortens the weld length, and improves the product qualification rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the high-strength and large aspect ratio combustion chamber casing of the present invention.

[0015] Figure 2 It is a structural diagram of a thin-wall shell welding tool in the manufacturing process of the present invention.

[0016] Figure 3 It is a structural diagram of the cylinder body Ⅰ of the present invention during spinning.

[0017] Figure 4 It is an installation diagram of a thin-wall shell welding tool when welding the front head and the cylinder body I in the manufacturing process of the present invention.

[0018] In the figure: 1-front head, 11-internal thread, 12-external thread, 2-cylinder body I, 3-cylinder body II, 4-rear head, 41-threaded hole, 5-centering part, 6-expansion block, 7-copper plate, 8-expansion cone, 9-core shaft, 10-pressure plate II, 13-pressure plate I, 14-pressure plate nut I, 15-pressure cover, 16-pressure plate nut II, 17-pressure cover nut, 18, mold, 19-return plate, 20-mold connector. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings.

[0020] like Figure 1 As shown, the high-strength and large aspect ratio combustion chamber casing of the present invention comprises a front end cap 1, a cylinder body Ⅰ 2, a cylinder body Ⅱ 3 and a rear end cap 4; the front end cap 1 is welded to the front end of the cylinder body Ⅰ 2, the rear end of the cylinder body Ⅰ 2 is welded to the front end of the cylinder body Ⅱ 3, and the rear end cap 4 is welded to the rear end of the cylinder body Ⅱ 3; the front end cap 1, the cylinder body Ⅰ 2, the cylinder body Ⅱ 3 and the rear end cap 4 are coaxial. An internal thread 11 connected to the ignition device is provided on the side wall of the front inner hole of the front end cap 1; an external thread 12 is provided on the front outer circle of the front end cap 1 for connecting with the aircraft. A plurality of threaded holes 41 are provided on the rear end surface of the rear end cap 4, and the plurality of threaded holes 41 are evenly arranged in the circumferential direction for connecting the engine nozzle. The wall thickness of the cylinder body Ⅰ 2 and the cylinder body Ⅱ 3 are both 2 mm. A centering portion 5 is provided on the outer circle of the front end cap 1, the cylinder body Ⅰ 2, the cylinder body Ⅱ 3 and the rear end cap 4, respectively, and the diameter of the centering portion 5 is 300 mm.

[0021] The manufacturing process of the high-strength and large-aspect-ratio combustion chamber casing of the present invention comprises the following steps: 1) Process the front head 1, cylinder Ⅰ2, cylinder Ⅱ3 and rear head 4.

[0022] a) The process of the front head 1 and the rear head 4 is the same, and the process is as follows: material collection → rough turning → ultrasonic flaw detection → semi-finishing turning → quenching and tempering → finishing turning → inspection → storage. The front head 1 and the rear head 4 are processed with round steel, and ultrasonic flaw detection is performed after rough turning, which meets the level 1 requirements of GB / T6402-91.

[0023] b) The manufacturing process of cylinder Ⅰ2 and cylinder Ⅱ3 is the same. The manufacturing steps of cylinder Ⅰ2 are as follows: receiving materials → rough turning → ultrasonic flaw detection → annealing → cutting (including test piece) → quenching and tempering → turning → inspection → spinning → inspection → ultrasonic flaw detection → storage. When spinning, steel pipe spinning is used, and the mold is installed and spun once, such as Figure 3 As shown, the mold 18 is coaxially connected to the main shaft of the spinning machine through the mold connector 20; the mold 18 is inserted into the center hole of the cylinder I2 and transitionally matched with the cylinder I2; the mold 18 is provided with a material removal plate 19, which is used to remove the spun cylinder I2 from the mold. After the cylinder I2 or the cylinder II3 is spun, it is tempered with the material heads at both ends. During the tempering, the shape correction tooling is used to ensure the straightness and roundness requirements of the cylinder I2 or the cylinder II3. After the tempering, the shape correction is performed to ensure that the difference between the maximum and minimum diameters is not greater than 1.5mm, and the straightness is not greater than 0.5mm.

[0024] 2) Weld the front head 1 and the cylinder Ⅰ2; Welding is carried out using thin-wall shell welding tools. Thin-wall shell welding tools such as Figure 2 As shown, it includes a mandrel 9, an expansion cone 8, a pressure plate Ⅰ13 and a pressure plate Ⅱ10. The two ends of the mandrel 9 are respectively provided with external threads. The expansion cone 8 is fixedly installed on the mandrel 9, and the expansion cone 8 is coaxial with the mandrel 9. A plurality of expansion blocks 6 are mounted on the side of the expansion cone 8. The plurality of expansion blocks 6 form an annular structure. The inner hole of the annular structure cooperates with the expansion cone 8. A copper plate 7 is provided on the outer surface of the expansion block 6. One end face of the expansion block 6 contacts one end of the pressure cover 15. The pressure cover 15 is sleeved on the mandrel 9 and is arranged close to the small end of the expansion cone 8. The other end of the pressure cover 15 contacts the pressure cover nut 17; the pressure cover nut 17 is screwed to the mandrel 9. The pressure plates Ⅰ13 and Ⅱ10 are sleeved on the mandrel 9 and are positioned by the pressure plate nut Ⅰ14 and the pressure plate nut Ⅱ16 respectively. The pressure plate Ⅰ13 is used to position the front head 1 or the rear head 4, and the pressure plate Ⅱ10 is used to position the cylinder Ⅰ2 or the cylinder Ⅱ3. The specific operation is as follows: First, insert the mandrel and the expansion block 6 and the gland 15 on the mandrel 9 into the center hole of the front head 1 and the cylinder Ⅰ2, and adjust the mandrel 9 so that the expansion block 6 is located at the gap between the front head 1 and the cylinder Ⅰ2. Adjust the gland nut 17 so that the outer side of the expansion block 6 presses against the inner wall of the front head 1 and the cylinder Ⅰ2. Set the pressure plate Ⅰ13 at the center hole of the end of the front head 1 facing away from the cylinder Ⅰ and fix it through the pressure plate nut Ⅰ14, set the pressure plate Ⅱ10 at the center hole of the end of the cylinder Ⅰ2 facing away from the front head and fix it through the pressure plate nut Ⅱ16, and adjust the gap between the front head 1 and the cylinder Ⅰ2 to 2-5mm by tightening the pressure plate nut Ⅰ14 and the pressure plate nut Ⅱ16. Preheat the welded parts (front head 1 and cylinder Ⅰ2), and the preheating temperature of the welded parts is 200℃. Then turn on the welding machine to weld the front head 1 and the cylinder Ⅰ2. The welding adopts argon arc welding, the welding power is 2.5kW, the welding speed is 1.8m / min, the spot diameter is 0.4mm, and the defocus is -0.2mm.

[0025] 3) Welding of cylinder Ⅰ2 and cylinder Ⅱ3 Remove the pressing plate Ⅰ13 and pressing plate Ⅱ10, and loosen the gland nut 17; sleeve the cylinder Ⅱ3 on the outside of the mandrel 9 so that the cylinder Ⅱ3 is set close to the cylinder Ⅰ2, and adjust the mandrel 9 so that the expansion block 6 is located at the gap between the opposite ends of the cylinder Ⅰ2 and the cylinder Ⅱ3. Adjust the gland nut 17 so that the outer side of the expansion block presses against the inner wall of the cylinder Ⅰ2 and the cylinder Ⅱ3. Set the pressing plate Ⅰ13 at the center hole of the end of the front head 1 facing away from the cylinder Ⅱ and fix it through the pressing plate nut Ⅰ14, set the pressing plate Ⅱ10 at the center hole of the end of the cylinder Ⅱ facing away from the front head and fix it through the pressing plate nut Ⅱ16, and adjust the gap between the front cylinder Ⅱ3 and the cylinder Ⅰ2 to 2-5mm by tightening the pressing plate nut Ⅰ14 and the pressing plate nut Ⅱ16. Preheat the welded parts (the front head 1, the cylinder Ⅰ2 and the cylinder Ⅱ3 that have been welded into one body), and the preheating temperature of the welded parts is 200℃. Then the welding machine is turned on to weld the cylinder II 3 and the cylinder I 2. The welding adopts argon arc welding, the welding power is 2.5kW, the welding speed is 1.8m / min, the spot diameter is 0.4mm, and the defocus amount is -0.2mm.

[0026] 4) Welding of cylinder II3 and rear head 4 Remove the pressing plate Ⅰ13 and pressing plate Ⅱ10, and loosen the gland nut 17. Sleeve the rear head 4 on the outside of the mandrel 9 so that the rear head 4 is set close to the cylinder Ⅱ3; and adjust the mandrel 9 so that the expansion block 6 is located at the gap between the cylinder Ⅱ3 and the rear head 4. Adjust the gland nut 17 so that the outer side of the expansion block 6 presses against the inner wall of the rear head 4 and the cylinder Ⅱ3. Set the pressing plate Ⅰ13 at the center hole of the end of the front head 1 facing away from the cylinder Ⅱ and fix it through the pressing plate nut Ⅰ14, set the other pressing plate Ⅰ13 at the center hole of the end of the rear head 4 facing away from the front head and fix it through another pressing plate nut Ⅰ, tighten the two pressing plate nuts Ⅰ14 to adjust the distance between the two pressing plates Ⅰ13, so that the gap between the head and the cylinder Ⅱ is 2-5mm. Preheat the welded parts (the front head 1, cylinder Ⅰ2 and cylinder Ⅱ3 and the rear head 4 that have been welded into one body), and the preheating temperature of the welded parts is 200℃. Then, the welding machine is turned on to weld the cylinder II 3 and the rear head 4; the welding adopts argon arc welding, the welding power is 2.5kW, the welding speed is 1.8m / min, the spot diameter is 0.4mm, and the defocus amount is -0.2mm, so as to form the combustion chamber shell.

[0027] 5) Remove the welding tooling of the thin-walled shell and perform X-ray inspection and / or fluorescent flaw detection on the welds. If there are unqualified welds, perform repair welding on the unqualified welds; after the welds are qualified, perform envelope circle inspection on the combustion chamber shell, perform tempering treatment on the combustion chamber shell, and at the same time, correct the shape of the combustion chamber shell.

[0028] During tempering, the combustion chamber shell is vertically hoisted and placed in the tempering furnace using a hoist. During tempering, the shaping tooling protects the processed and formed surface to prevent surface decarburization. The shaping rigid ring and shaping support are used for shaping. After shaping, the outer envelope size of the combustion chamber shell is tested. The outer envelope size of the shell part outside the elastic band is required to be no greater than Φ299.8mm. If the requirements are not met, adjustments are allowed while ensuring the processing requirements of the guide ring. If the requirements are still not met, tempering and shaping are performed again.

[0029] 6) Grind the weld, tap the multiple threaded holes 41 of the rear head 4, and remove burrs and rust from the outer surface of the combustion chamber shell. Then, roughly bore the inner cavity of the combustion chamber shell, and perform a water pressure test on the combustion chamber shell at a pressure of 15-16MPa, stabilizing the pressure for 25s. After the water pressure test, perform X-ray inspection or / and fluorescent flaw detection on the weld, and turn the external thread 12 and internal thread 11 of the front head 1; fine bore the inner cavity of the combustion chamber shell, remove burrs from the inner cavity of the combustion chamber shell, inspect, and store qualified products.

Claims

1. A high-strength, high-aspect-ratio combustion chamber casing, characterized by: It includes a front head, a cylinder body I, a cylinder body II and a rear head; the front head is welded to the front end of the cylinder body I, the rear end of the cylinder body I is welded to the front end of the cylinder body II, and the rear head is welded to the rear end of the cylinder body II; the front head, cylinder body I, cylinder body II and the rear head are coaxial; an internal thread connected to the ignition device is arranged on the side wall of the front inner hole of the front head; an external thread is arranged on the front outer circle of the front head for connection with the aircraft; a plurality of threaded holes are arranged on the rear end surface of the rear head, and the plurality of threaded holes are evenly arranged along the circumferential direction for connecting to the engine nozzle.

2. The high-strength and high-aspect-ratio combustion chamber casing according to claim 1 is characterized in that: The wall thickness of cylinder Ⅰ and cylinder Ⅱ is 2mm.

3. The high-strength and high-aspect-ratio combustion chamber casing according to claim 1 is characterized in that: A centering portion is respectively provided on the outer circles of the front head, cylinder body I, cylinder body II and the rear head, and the diameter of the centering portion is 300 mm.

4. A manufacturing process for a high-strength and high-length-diameter-ratio combustion chamber casing, used for manufacturing the high-strength and high-length-diameter-ratio combustion chamber casing according to any one of claims 1 to 3, comprising the following steps: 1) Processing the front head, cylinder I, cylinder II and rear head; 2) Weld the front head and cylinder I; The welding is carried out by a thin-walled shell welding tool, which includes a mandrel, an expansion cone, a pressure plate I and a pressure plate II. External threads are respectively provided at both ends of the mandrel, and an expansion cone is fixedly installed on the mandrel. The expansion cone is coaxial with the mandrel. A plurality of expansion blocks are mounted on the side of the expansion cone. The plurality of expansion blocks form an annular structure. The inner hole of the annular structure cooperates with the expansion cone. A copper plate is provided on the outer surface of the expansion block. One end face of the expansion block contacts one end of a gland. The gland is sleeved on the mandrel and arranged close to the small end of the expansion cone. The other end of the gland contacts the gland nut. The gland nut is threaded with the mandrel. Pressure plates I and II are sleeved on the mandrel and positioned by pressure plate nut I and pressure plate nut II respectively. Pressure plate I is used to position the front head or the rear head, and pressure plate II is used to position the cylinder I or the cylinder II. First, insert the mandrel and the expansion block and pressure cover on the mandrel into the center hole of the front head and the cylinder body I, and adjust the mandrel so that the expansion block is located at the gap between the front head and the cylinder body I at the opposite ends; adjust the pressure cover nut so that the outer side of the expansion block presses against the inner wall of the front head and the cylinder body I; set the pressure plate I at the center hole of the end of the front head facing away from the cylinder body I and fix it through the pressure plate nut I, set the pressure plate II at the center hole of the end of the cylinder body I facing away from the front head and fix it through the pressure plate nut II, and adjust the gap between the front head and the cylinder body I to 2-5mm by tightening the pressure plate nut I and the pressure plate nut II; then turn on the welding machine to weld the front head and the cylinder body I; 3) Welding of cylinder I and cylinder II Remove the pressing plate I and II, and loosen the gland nut; put the cylinder II on the outside of the mandrel so that the cylinder II is set close to the cylinder I, and adjust the mandrel so that the expansion block is located at the gap between the opposite ends of the cylinder I and the cylinder II; adjust the gland nut so that the outer side of the expansion block presses against the inner wall of the cylinder I and the cylinder II; set the pressing plate I at the center hole of the end of the front head facing away from the cylinder II and fix it through the pressing plate nut I, set the pressing plate II at the center hole of the end of the cylinder II facing away from the front head and fix it through the pressing plate nut II, and adjust the gap between the front cylinder II and the cylinder I to 2-5mm by tightening the pressing plate nut I and the pressing plate nut II; then turn on the welding machine to weld the cylinder II and the cylinder I; 4) Welding of cylinder II and rear head Remove the pressure plate I and pressure plate II, and loosen the gland nut; put the rear head on the outside of the core shaft so that the rear head is set close to the cylinder II; and adjust the core shaft so that the expansion block is located in the gap between the cylinder II and the rear head; adjust the gland nut so that the outer side of the expansion block presses against the inner wall of the rear head and the cylinder II; set the pressure plate I at the center hole of the end of the front head facing away from the cylinder II and fix it through the pressure plate nut I, set the other pressure plate I at the center hole of the end of the rear head facing away from the front head and fix it through another pressure plate nut I, and adjust the distance between the two pressure plates I by tightening the two pressure plate nuts I so that the gap between the head and the cylinder II is 2-5mm; then turn on the welding machine to weld the cylinder II and the rear head to form the combustion chamber shell; 5) Remove the welding tooling of the thin-walled shell and perform non-destructive testing on the welds; if any welds are unqualified, perform repair welding on the unqualified welds; After the weld is qualified, the combustion chamber shell is tested for envelope circle and tempered; at the same time, the combustion chamber shell is calibrated; 6) Grind the weld, tap the multiple threaded holes of the rear head, and remove burrs and rust from the outer surface of the combustion chamber shell; then rough bore the inner cavity of the combustion chamber shell, perform a water pressure test on the combustion chamber shell, perform non-destructive testing on the weld again after the water pressure test, turn the external and internal threads of the front head; fine bore the inner cavity of the combustion chamber shell, remove burrs from the inner cavity of the combustion chamber shell, inspect, and put the qualified products into storage.

5. According to the manufacturing process of the high-strength and large aspect ratio combustion chamber shell of claim 4, the welding in steps 2)-4) adopts argon arc welding, and the parts to be welded are preheated before welding, and the preheating temperature of the parts to be welded is 200°C; the welding power is 2.5kW, the welding speed is 1.8m / min, the spot diameter is: 0.4mm, and the defocus amount is -0.2mm.

6. According to the manufacturing process of the high-strength and large aspect ratio combustion chamber casing of claim 4, in steps 5) and 6), X-ray detection and / or fluorescent flaw detection are used to perform non-destructive testing on the weld.

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