Forming die, positioning tool, method for manufacturing regenerative cooling nozzle, and cooling nozzle

Abstract

The application discloses a forming die, a positioning tool, a regenerative cooling nozzle preparation method and a cooling nozzle, and belongs to the field of regenerative cooling nozzle preparation. The forming die comprises a reference uniform structure for clamping a cylinder blank. The reference uniform structure comprises an inner core and an annular positioning table integrally formed on the bottom circumference side of the inner core. The top circumference of the inner core is uniformly and threadedly connected with a plurality of trapezoidal positioning pressing blocks, so that the cylinder blank is clamped and positioned between the trapezoidal positioning pressing blocks and the outer side of the inner core. The profile of the inner core is consistent with the design curve generatrix profile of the regenerative cooling nozzle, and the outer profile of the inner core is fitted with the inner hole of the cylinder blank. The forming die, the positioning tool, the regenerative cooling nozzle preparation method and the cooling nozzle solve the problems of poor tool positioning adaptability, difficult control of the gap between the inner and outer layers of the nozzle, easy oxidation of the weld and long processing cycle in the preparation of the titanium alloy nozzle of the existing rocket engine, and realize the collaborative optimization of the nozzle preparation precision, production efficiency and use performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of regenerative cooling nozzle preparation, in particular to a forming die, a positioning tool, a regenerative cooling nozzle preparation method and a cooling nozzle. BACKGROUND

[0002] As a core thermal protection component of aerospace propulsion systems, the regenerative cooling nozzle realizes thermal protection through the flow of coolant in the gap between the inner and outer nozzles, directly ensuring the stable operation of the propulsion system under high temperature and high pressure conditions. The spinning process is the core process for preparing the pre-formed cylinder blank of the regenerative cooling nozzle (inner nozzle, outer nozzle). In the existing process, the pipe blank is directly fixed to the spinning machine core die by a three-jaw chuck, and the pipe blank is locally plastically deformed by the pressure of the spinning wheel in each pass, the wall thickness is thinned and a complex curved surface is formed. However, the spinning machine core die used only serves as a profile carrier for spinning forming, and does not establish a unified positioning reference with the subsequent welding tool, resulting in that the radial gap between the inner and outer nozzles is still difficult to control within the preset range of ≤0.15mm. SUMMARY

[0003] The purpose of the present application is to provide a forming die, a positioning tool, a regenerative cooling nozzle preparation method and a cooling nozzle, which solve the above technical problems.

[0004] To achieve the above-mentioned purpose, the present application provides a forming die, which comprises a reference unification structure for clamping a cylinder blank, the reference unification structure comprising an inner core and an annular positioning table integrally formed on the bottom circumference side of the inner core, the annular positioning table being fixed with a base on the side away from the inner core, and the top circumference of the inner core being uniformly screw-connected with a plurality of trapezoidal positioning blocks, so as to realize the positioning and clamping of the cylinder blank on the outer side of the inner core between the trapezoidal positioning blocks and the annular positioning table of the annular positioning table step.

[0005] The profile of the inner core is consistent with the design curve generatrix profile of the regenerative cooling nozzle, and the outer contour of the inner core is fitted with the inner hole of the cylinder blank without obvious shaking.

[0006] Preferably, the present application further comprises a lower pressing ring, which is sleeved on the outer side of the cylinder blank, and a plurality of U-shaped connecting blocks are uniformly arranged on the circumference side of the lower pressing ring, and the plurality of U-shaped connecting blocks are connected with the base through the first adjusting screw for applying axial tension to the lower pressing ring to drive the lower pressing ring to press the cylinder blank onto the inner core.

[0007] The side of the trapezoidal positioning block facing the cylinder blank is bonded with a silicone rubber pad; the reference unification structure is subjected to quenching and tempering treatment of 45# steel, with a hardness of HRC28-32, so as to ensure that the tool inner core has sufficient rigidity and avoids the influence of inner core deformation on the nozzle profile accuracy during the spinning process.

[0008] The positioning tooling includes a forming die and an upper pressing ring, an inner layer nozzle is attached to the outside of the inner core of the forming die, an outer layer nozzle is sleeved on the outside of the inner layer nozzle, and the outer circumference side of the outer layer nozzle is sequentially sleeved with the upper pressing ring and a lower pressing ring from top to bottom, wherein the lower pressing ring is used to apply axial tension to the outer layer nozzle so as to press the outer layer nozzle onto the inner layer nozzle;

[0009] The upper end surface of the upper pressing ring is positioned by a plurality of radial adjusting assemblies that are uniformly distributed on the upper end surface of the inner core, and the boss axial pressing surface of the upper pressing ring is in pressure contact with the top end of the outer layer nozzle.

[0010] Preferably, the radial adjusting assembly includes a second adjusting screw threadedly connected to the top end of the inner core and a pressing jaw threadedly connected with the second adjusting screw, the bottom end of the pressing jaw is integrally formed with a rear arc-shaped pressing block, the arc-shaped pressing block is in abutment with the upper end surface of the upper pressing ring, and precise adjustment within the range of 0-10mm in axial height can be achieved.

[0011] Silicone rubber pads with a thickness of 0.5mm are bonded to the side of the trapezoidal positioning pressing block facing the inner layer nozzle and the side of the arc-shaped pressing block facing the upper pressing ring, which have flexibility and wear resistance, can avoid scratching the nozzle when pressing, and can adapt to the profile error of the upper pressing ring through slight deformation to ensure uniform transmission of the pressing force.

[0012] The method for preparing a regenerative cooling nozzle includes the following steps:

[0013] S1, preparing a preformed cylinder blank: first, a metal plate is made into a fan-shaped blank, then the fan-shaped blank is pre-bent by roll bending to prepare a cylinder blank, after stress relief, the inner layer nozzle and the outer layer nozzle are respectively clamped on the workbench of a spinning machine using a forming die to prepare a profiled cylinder blank, and finally the inner and outer surfaces of the profiled cylinder blank are treated to prepare the inner layer nozzle and the outer layer nozzle;

[0014] S2, processing axial cooling flow grooves: taking the inner hole of the inner layer nozzle as a reference, the forming die sleeved with the inner layer nozzle is clamped on a five-axis machining center, and then axial cooling flow grooves are processed on the outer surface of the inner layer nozzle, and adjacent two axial cooling flow grooves are separated by a rib;

[0015] S3, pre-assembling the outer layer nozzle and the inner layer nozzle with axial cooling flow grooves to ensure that the radial gap and the end face flatness meet the welding requirements;

[0016] S4, coaxially assembling the nozzle main body assembly: the inner layer nozzle and the outer layer nozzle are coaxially positioned and the radial gap is locked using the positioning tooling to form a nozzle main body assembly;

[0017] S5, laser welding of the nozzle main body assembly: under the action of a double-layer coaxial protective cover, the rib longitudinal seam welding area of the outer layer nozzle and the inner layer nozzle of the nozzle main body assembly is laser welded to form a sealed nozzle main body;

[0018] S6, collector integrated welding: using the metal elbow pipe after slitting to weld tee pipe and flange, the inlet collector and outlet collector are prepared, and then the inlet collector and outlet collector are respectively connected with the upper and lower ends of the nozzle body in the form of angular joint and are full-welded by argon arc welding to form a regenerative cooling nozzle assembly;

[0019] S7, performance verification and finished product processing: after the regenerative cooling nozzle assembly is deburred, it is ultrasonically cleaned by 5% neutral degreasing agent, and the axial cooling flow channel is blown; performance verification is performed by pressure test and liquid flow experiment; and the regenerative cooling nozzle assembly that passes the verification is dried at 80-100℃ for 2-3h to obtain a regenerative cooling nozzle.

[0020] Preferably, step S1 specifically comprises the following steps:

[0021] S11, material selection and blanking: selecting a metal plate material suitable for the working condition, determining the unfolded size of the inner nozzle and the outer nozzle by computer-aided design software and reserving a 1.5% forming shrinkage allowance, and using numerical control laser cutting to blank the fan-shaped blank to ensure that the plate edge roughness Ra≤1.6μm;

[0022] S12, rolling and longitudinal seam welding: the fan-shaped blank after blanking is pre-bent into a straight cylinder blank that is suitable for the contour of the inner core and outer wheel by a three-roll bending machine, and the longitudinal seam is welded under the condition that the protective gas is argon with a purity of ≥99.99% and the flow rate is 12-15L / min, the weld transition area is polished after welding to make the weld surface roughness Ra≤1.6μm, the weld reinforcement is controlled to be 0.3-0.5mm, the weld and the base material form a smooth transition without protrusions, depressions and sharp corners, and penetration detection is performed to obtain the cylinder blank;

[0023] S13, stress relief annealing: the welded cylinder blank is placed in a heating furnace for stress relief annealing to eliminate the welding internal stress, wherein the annealing temperature of the titanium alloy cylinder blank is 550-750℃, and the cylinder blank is cooled in the furnace after being kept for 15-60min; the hardness of the cylinder blank is detected after annealing to ensure that the hardness of the titanium alloy is HV280-320;

[0024] S14, spinning forming: the annealed cylinder blank is sleeved outside the inner core of the forming die, the lower end surface of the cylinder blank abuts against the annular positioning support step on the inner core, the trapezoidal positioning pressure block at the top of the inner core is tightened to realize the axial and radial positioning of the cylinder blank, then a lower pressing ring is sleeved outside the cylinder blank to press the cylinder blank tightly to the outside of the inner core, the forming die is clamped on the spinning machine workbench (i.e. the forming die is positioned between the three-jaw chuck and the tail seat top rod of the spinning machine workbench), and the coaxiality between the cylinder blank axis and the spinning machine spindle is ensured to be ≤0.01mm by positioning pins, the spinning machine is opened, and the cylinder blank is formed into a profiled cylinder blank;

[0025] S15, clamp the spun profiled cylinder blank on the numerical control lathe, process the inner and outer surfaces of the profiled cylinder blank, and obtain the inner layer nozzle and the outer layer nozzle.

[0026] Preferably, step S4 specifically comprises the following steps:

[0027] S41, positioning and calibration of the tooling: install the reference unified structure of the positioning tooling to the workbench of the positioner, fix it by cooperating the reference holes of the workbench with the positioning pins; detect the coaxialities of 6 points along the outer circumference of the inner core with a micrometer, and adjust the positioning tooling until the coaxiality between the axis of the inner core and the axis of the main shaft of the positioner is ≤0.01mm, to ensure the accuracy of the subsequent assembly reference;

[0028] S42, clamping and fixing of the inner layer nozzle: put the pre-assembled qualified inner layer nozzle of step S3 into the outer side of the inner core of the positioning tooling, so that the lower end face of the pre-assembled qualified inner layer nozzle abuts against the annular positioning support step of the inner core; tighten the trapezoidal positioning blocks evenly distributed on the top of the inner core to realize the axial and radial positioning of the inner layer nozzle; detect the radial runout of 6 points along the outer circumference of the inner layer nozzle with a micrometer, to ensure that the radial runout is ≤0.02mm, and complete the positioning of the inner layer nozzle;

[0029] S43, installation and axial limiting of the outer layer nozzle: put the pre-assembled qualified outer layer nozzle of step S3 into the outer side of the inner layer nozzle, then put the lower pressing ring into the outer side of the outer layer nozzle, and then tighten the first adjusting screw to press the outer layer nozzle to the outer side of the inner layer nozzle (i.e. after putting the lower pressing ring into the outer side of the outer layer nozzle, then screwing the first adjusting screw into the U-shaped connecting block and connecting the base of the reference unified structure, so as to press the outer layer nozzle tightly to the outer side of the inner layer nozzle by using the downward force of the adjusting screw), and make the upper end face of the outer layer nozzle abut against the stepped face of the upper pressing ring to limit the initial position of the outer layer nozzle in the axial direction;

[0030] It should be noted that the height of the outer layer nozzle is lower than that of the inner layer nozzle, so there is a distance between the bottom end face of the outer layer nozzle and the bottom of the inner layer nozzle , so the distance needs to be covered by the lower pressing ring , and a pressing contact allowance is reserved . Therefore, the height of the lower pressing ring is designed .

[0031] S44, radial gap regulation and locking: put the upper pressing ring into the outer side of the outer layer nozzle, and turn the second adjusting screw to drive the pressing jaw and the arc-shaped pressing block to press the upper pressing ring downward under the cooperation of the threads; insert the feeler gauge into the gap detection channel of the inner core to measure the radial gap of 6 points of the inner layer nozzle and the outer layer nozzle, and gradually turn the second adjusting screw until the gap of all points is ≤0.15mm, lock the second adjusting screw, and form the nozzle main body assembly.

[0032] Preferably, the double-layer coaxial protective cover in step S5 is installed on the welding gun of the laser welding machine, and a main shaft through hole with a size matching the spot size of the laser welding machine and a spiral flow guide groove arranged outside the main shaft through hole are formed in the center of the double-layer coaxial protective cover, and the outlet end of the spiral flow guide groove is flush with the lower end surface of the main shaft through hole;

[0033] The outer layer gas inlet and the inner layer gas inlet are sequentially formed on the side wall of the double-layer coaxial protective cover from outside to inside and in the axial direction, and both the outer layer gas inlet and the inner layer gas inlet are inclined towards the outlet direction of the double-layer coaxial protective cover, and the inlet end of the outer layer gas inlet and the inner layer gas inlet is communicated with the inert gas preheating tank through an independent pipeline, and the outlet end of the inner layer gas inlet is communicated with the spiral flow guide groove, and the inert gas preheating tank is communicated with a high-purity argon gas supply tank with a purity of ≥99.999%;

[0034] The outer layer gas inlet and the inner layer gas inlet are both left with an annular air gap of 10-12mm between the main shaft, and a screen is arranged at the outlet of the double-layer coaxial protective cover;

[0035] It specifically includes the following steps:

[0036] S51, pretreatment before welding: polish the rib butt joint area of the outer layer nozzle and the inner layer nozzle of the nozzle body assembly with sandpaper to remove surface oxide scale and impurities; then wipe the area clean with acetone, and then blow off residual dust and waste liquid with compressed air to ensure that the welding area is free of oil stains and foreign matter; finally, clamp the treated nozzle body assembly on the positioner, detect the circular runout of 6 points along the outer circumference of the outer layer nozzle with a dial gauge, and adjust the clamping position until the circular runout is ≤0.15mm;

[0037] S52, inert gas protection structure building and argon gas covering: install the double-layer coaxial protective cover to the welding gun clamping mechanism of the laser welding machine, and adjust the distance between the double-layer coaxial protective cover and the outer surface of the outer layer nozzle to 8-12mm; at the same time, the inner layer gas inlet argon gas is at a flow rate of 15-20L / min, and the outer layer gas inlet is at a flow rate of 8-12L / min, forming an annular air curtain to block the diffusion of external air to the molten pool area; at the same time, the upper and lower ends of the nozzle body assembly are covered with sealing rings to achieve sealing of the upper and lower ends of the nozzle body assembly, and the sealing ring at the lower end and the sealing ring at the upper end are prearranged with argon gas inlets and argon gas outlets, the argon gas inlets are connected to a high-purity argon gas supply tank with a purity of ≥99.999%, and the argon gas outlets are connected to a waste gas collection pipeline; start the inert gas preheating tank, preheat the argon gas to 80-100℃, and pass the preheated argon gas into the sealing ring at the lower end through the argon gas inlets, and then evenly distribute the argon gas from the sealing ring at the lower end to the welding seam back surface area corresponding to each axial cooling flow groove to ensure that each welding seam back surface is covered with argon gas;

[0038] S53, laser welding parameter setting and welding: using a fiber laser welding machine to weld according to the principle of diagonal partition alternation, the circumference of the nozzle is divided into 360° / N° symmetrical partitions according to every N° (the preset partition angle N° needs to meet two conditions: ① 360 can be divided by N, to ensure the symmetry of the partition circumferential direction; ② X can be divided by 360 / N, to ensure that the number of ribs in each partition is equal), and one rib in each partition is welded with the butt joint longitudinal seam of the outer nozzle; after the weld in the previous partition cools to below 200℃, the longitudinal seam of the center symmetrical partition is welded to ensure that the welding stress is evenly dispersed;

[0039] S54, inert atmosphere cooling: after welding, keep the argon gas supply system and the double-layer protective cover running to cool the nozzle body to room temperature in an inert atmosphere to avoid oxidation of the weld joint by contacting air;

[0040] S55, weld quality detection: all welds are subjected to penetration detection; then the edges of the welds are polished with sandpaper to make the roughness Ra of the weld transition area ≤1.6μm, forming a sealed nozzle body.

[0041] In the above welding process of the longitudinal seam, the process lines on the upper and lower ends of the inner nozzle are used in cooperation with the high-definition vision camera integrated in the laser welding head to determine the position of the longitudinal seam, and the specific steps are as follows:

[0042] First, control the laser head to scan along the circumference of the outer surface of the outer nozzle, and collect the process lines on the upper and lower ends of the ribs of the inner nozzle;

[0043] Then, based on the extension direction of the process lines, guide the laser light path to align with the center line of each rib (determine the position of the longitudinal seam), ensure that the initial positioning deviation of the light path and the center of the rib is ≤0.05mm, and the path fits the curvature of the outer surface profile of the outer nozzle without local protrusions or depressions.

[0044] Preferably, step S6 specifically includes the following steps:

[0045] S61, collector body processing: select a seamless metal pipe made of the same material as the nozzle body, bend it into a circular pipe through a pipe bender, the inner diameter of the circular pipe is adapted to the outer diameter of the outer nozzle, and the fitting clearance is ≤0.1mm; clamp the circular pipe on a numerical control lathe and finish machining the inner surface to a roughness Ra of ≤0.8μm; at the center position of the outer wall of the circular pipe, a 45° bevel is opened at the fitting position of the branch pipe of the tee joint, the bevel depth is 1 / 2 of the metal pipe wall thickness, and the burrs at the edge of the bevel are removed;

[0046] S62, collector joint welding: select the same material tee joint, 90° elbow and flange, first the tee joint branch port and the circular pipe groove coaxial butt joint, under the condition of argon gas purity ≥ 99.999%, flow 15L / min, full welding is carried out by argon arc welding; then one end of the 90° elbow is coaxially connected with the main pipe port of the tee joint, and the other end is full welded with the end surface of the flange; during the welding process, the perpendicularity between the flange surface and the 90° elbow axis is calibrated by using a right angle ruler, and the perpendicularity is less than or equal to 0.02mm; then the penetration detection is carried out, and the inlet collector and the outlet collector are prepared;

[0047] S63, collector and nozzle body butt joint positioning: the nozzle body is clamped in the centering tool of the rotary workbench, the outer circle of the nozzle body is taken as the reference, the nozzle body axis is calibrated by using a dial gauge, and the axis runout is ensured to be less than or equal to 0.01mm; the inlet collector and the outlet collector are respectively butt jointed to the upper and lower ends of the nozzle body, the supporting mandrel is inserted into the nozzle body inner core, the coaxiality between the collector circular pipe axis and the nozzle body axis is ensured to be less than or equal to 0.02mm, and the butt joint gap is detected by using a feeler gauge, and the gap is ensured to be less than or equal to 0.1mm;

[0048] S64, full welding of angle joint argon arc welding: the butt joint of the collector and the nozzle body is full welded by using a pulse argon arc welding machine, and a closed annular flow collecting cavity is formed; during the welding process, argon gas with purity greater than or equal to 99.999% and flow 15L / min is continuously introduced for protection;

[0049] S65, weld cleaning and detection: after welding, the edge of the butt joint of the collector and the nozzle body is polished by hand with sandpaper, so that the roughness Ra of the transition area is less than or equal to 3.2μm; then the flow collecting cavity and the axial cooling flow groove are blown by compressed air; then the penetration detection is carried out on all the angle joint welds, and the regenerative cooling nozzle assembly is formed.

[0050] The cooling nozzle prepared by the regenerative cooling nozzle preparation method comprises an inner layer nozzle and an outer layer nozzle which are of the same material and have an inner and outer welding structure, an axial cooling flow groove is formed on one side of the inner layer nozzle facing the outer layer nozzle, and the axial cooling flow groove adopts a variable cross-section structure.

[0051] Therefore, the present application has the beneficial effects of the above forming die, positioning tool, regenerative cooling nozzle preparation method and cooling nozzle, which are as follows:

[0052] 1. The tool versatility is improved, the cost and switching time are reduced: the tool assembly is unified, a single tool can adapt to nozzles of different thicknesses and different heights, the number of special tools is reduced by more than 60%, the tool switching time is shortened from 2 hours to 30 minutes, and the tool investment cost and production preparation time are greatly reduced;

[0053] 2. Optimization of forming and assembly precision, guaranteeing cooling performance: the positioning datum of the forming die and the positioning tooling is unified, the gap between the inner layer nozzle and the tooling inner core is less than 0.05 mm, the radial gap between the inner and outer layer nozzles is less than or equal to 0.1 mm, the deviation of the cooling flow groove cross-sectional area from the design value is less than or equal to 5%, the flow consistency is improved by 30%, the coolant flow deviation is avoided, and the regenerative cooling efficiency is guaranteed;

[0054] 3. Excellent weld quality, improving structural reliability: through the double-layer coaxial protective cover (inner layer rotating gas column protecting the molten pool, outer layer air curtain blocking air) + 80-100 DEG C preheating argon + inert atmosphere slow cooling, the weld oxidation color grade is less than or equal to 1, the oxygen content is less than or equal to 0.05%, and the joint tensile strength is improved by 20%; the collector adopts a 45 DEG bevel and pulse argon arc welding, the overall nozzle is tested by pressing for 30 MPa for 30 minutes, without bulging, leakage and pressure drop phenomenon, meeting the sealing requirements under high temperature and high pressure;

[0055] 4. Improved production efficiency, suitable for batch production: optimizing the process flow (such as integrated spinning-welding datum, partitioned alternating welding), the processing cycle is shortened by 40%, the manufacturing cost is reduced by 40%, the product consistency is more than 98%, and large-scale batch production can be realized.

[0056] The technical solutions of the present application will be further described in detail below through the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 It is a perspective view of the regenerative cooling nozzle of the present application;

[0058] Figure 2 It is an external surface structure diagram of the inner layer nozzle of the regenerative cooling nozzle of the present application;

[0059] Figure 3 It is a structure diagram of the forming die of the present application;

[0060] Figure 4 It is a slot milling state diagram of the present application;

[0061] Figure 5 It is a positioning tooling perspective view of the regenerative cooling nozzle preparation method of the present application;

[0062] Figure 6 It is an axial sectional view of the positioning tooling of the regenerative cooling nozzle preparation method of the present application;

[0063] Figure 7 It is an enlarged view of A of Figure 6 ;

[0064] Figure 8 It is an enlarged view of B of Figure 6 ;

[0065] Figure 9Longitudinal seam welding schematic diagram for the preparation method of the regenerative cooling nozzle of the present application;

[0066] Figure 10 Radial sectional view of longitudinal seam welding for the preparation method of the regenerative cooling nozzle of the present application;

[0067] Figure 11 Longitudinal seam partition welding schematic diagram for the preparation method of the regenerative cooling nozzle of the present application;

[0068] Figure 12 Axial sectional view of the double-layer coaxial protective cover for the preparation method of the regenerative cooling nozzle of the present application;

[0069] Figure 13 External view of the double-layer coaxial protective cover for the preparation method of the regenerative cooling nozzle of the present application;

[0070] Figure 14 Collector welding position diagram for the preparation method of the regenerative cooling nozzle of the present application.

[0071] Reference signs

[0072] 1, outer nozzle; 2, inner nozzle; 3, outlet collector; 4, inlet collector; 5, flange; 6, 90° elbow; 7, axial cooling flow groove; 8, inner core; 9, annular positioning platform; 10, three-jaw chuck; 11, ejector rod; 12, upper compression ring; 13, lower compression ring; 131, U-shaped connecting block; 14, compression jaw; 15, trapezoidal positioning compression block; 16, arc-shaped compression block; 17, welding gun clamping mechanism; 18, double-layer coaxial protective cover; 19, inert gas preheating tank; 20, high-purity argon gas supply tank; 21, rib; 22, outer layer gas inlet; 23, inner layer gas inlet; 24, spiral flow guide groove; 25, screen; 26, annular positioning support step; 27, base. DETAILED DESCRIPTION

[0073] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the embodiments of the present application are further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present application and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application. The examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout.

[0074] It is to be understood that the terms "including", "comprising", "having" and their conjugates mean "including but not limited to", e.g. a process, method, object, or server that comprises a list of steps or elements is not necessarily limited to those specifically listed and can include other steps or elements not expressly listed or inherent to such process, method, object, or apparatus.

[0075] Embodiments of the present application will be described in detail below with reference to the drawings.

[0076] As Figures 1-14 shown.

[0077] Example 1: This example is directed to the preparation of a TA15 titanium alloy regenerative cooled nozzle for a rocket engine under aerospace high temperature and high pressure conditions, with the following specific parameters:

[0078] Outer nozzle 1: thickness 1.4 mm, large end diameter 480 mm, small end diameter 219 mm, height 256 mm;

[0079] Inner nozzle 2: thickness 2.6 mm, height 283 mm;

[0080] Axial cooling flow grooves 7: number 360, depth 2 mm, width 0.9-3.1 mm;

[0081] Sealing ring: in communication with all axial cooling flow grooves 7, forming a coolant shunt / confluence channel.

[0082] The preparation steps are as follows:

[0083] S1, preparation of a preformed cylinder blank;

[0084] S11, material selection and blanking: select 3 mm thick TA15 titanium alloy plate (for outer nozzle 1) and 5 mm thick TA15 titanium alloy plate (for inner nozzle 2), calculate the cone cylinder unfolding size by computer aided design software (such as CAD): outer nozzle 1 unfolding length 1145 mm, width 567 mm, inner nozzle 2 unfolding length 1174 mm, width 580 mm, reserve 1.5% forming shrinkage allowance; adopt numerical control laser cutting to blank into sector blanks, ensure that the plate edge roughness Ra≤1.6 μm.

[0085] S12, roll and longitudinal seam welding: put the sector blank into the three-roll bending machine for pre-bending, the pre-bending radius is 40 mm (consistent with the small end radius of the nozzle), roll into a straight cylinder blank that fits the outer contour of the inner core 8 of the forming die; the longitudinal seam is argon arc welded, the protective gas is argon with a purity of ≥99.999% (flow rate 14 L / min), the distance between the welding gun nozzle and the weld is 5-8 mm; the inner nozzle 2 welding parameters: current 120 A, welding speed 6 mm / s, arc voltage 20 V; the outer nozzle 1 welding parameters: current 100 A, welding speed 5 mm / s, arc voltage 18 V; after welding, use an angle grinder with 800# sandpaper to polish the weld transition area to a roughness of Ra≤3.2 μm, and perform penetration testing (PT), which meets the requirements of GB / T18851.1-2022 Grade I, to obtain the cylinder blank.

[0086] S13, stress relief annealing: place the welded cylinder blank into a pit furnace, introduce nitrogen gas with a purity of ≥99.999% for protection, heat to 580℃, and after holding for 30 min, cool down with the furnace; after annealing, detect the hardness of the cylinder blank to ensure that the hardness is controlled within HV280-320, and eliminate the welding internal stress.

[0087] S14, spinning forming: after annealing, the cylinder blank is sleeved outside the inner core 8 of the forming die, and abuts against the annular support step 26 of the annular positioning table on the inner core, and the trapezoidal positioning block 15 at the top of the inner core 8 is tightened (0.5 mm thick silicone rubber pad is attached to the inner side of the block), achieving axial and radial positioning of the cylinder blank; the cylinder blank is clamped on the spinning machine workbench (i.e. the forming die is positioned between the three-jaw chuck 10 and the tail seat top rod 11 of the spinning machine workbench, i.e. the base 27 at one end of the forming die is clamped with the three-jaw chuck 10 of the spinning machine workbench, and the other end abuts against the tail seat top rod 11), and the coaxiality of the cylinder blank axis and the spinning machine spindle is ensured to be ≤0.01 mm by positioning pins; hot spinning process is adopted (spinning temperature 800℃, real-time monitoring by infrared temperature detector), the spinning wheel feed speed is 2 mm / s, and the spinning wheel pressure is 80 kN, until the cylinder blank is formed into a contoured cylinder blank; after demolding, the outer nozzle 1 profile error is ≤±0.05 mm and the inner nozzle 2 inner hole cylindricity is ≤0.02 mm, which are detected by a three-coordinate measuring instrument.

[0088] S15, inner and outer surface processing: the contoured cylinder blank after spinning is clamped on a numerical control lathe: the outer surface of the outer nozzle 1 is finished to a roughness of Ra≤1.6 μm (cutting parameters: speed 1500 r / min, feed speed 100 mm / min, back engagement amount 0.2 mm); the outer surface of the inner nozzle 2 is finished to a roughness of Ra≤1.6 μm (cutting parameters: speed 1800 r / min, feed speed 80 mm / min, back engagement amount 0.15 mm), to obtain the inner nozzle 2 and the outer nozzle 1.

[0089] S2, machining axial cooling flow groove 7: the inner layer nozzle 2 is clamped in the five-axis machining center, and the inner hole is precisely machined as the positioning reference (three-jaw chuck 10+tail seat top cooperation, clamping coaxiality ≤0.01mm); select custom composite coated carbide end mill, mill outer surface axial cooling flow groove 7 and rib 21; milling parameters: rough milling speed 2800r / min, feed speed 180mm / min, back engagement 1mm, fine milling speed 3800r / min, feed speed 100mm / min, back engagement 0.2mm; cooling method: oil mist cooling (concentration 80%, pressure 0.3MPa)+0.4MPa compressed air purge; after milling detection: rib 21 width 1.1mm (tolerance ±0.03mm), inner wall roughness Ra≤0.8μm, prepare the inner layer nozzle 2 with cooling flow.

[0090] S3, pre-assemble outer nozzle 1 and inner nozzle 2: the outer nozzle 1 is sleeved outside the inner nozzle 2, the radial clearance of 6 points is detected by feeler gauge, and the clearance is ensured to be in the range of 0-0.15mm; at the same time, the end face flatness of the outer nozzle 1 and the inner nozzle 2 is detected, and the misalignment of the two end faces is ensured to be ≤0.05mm, which meets the subsequent welding requirements.

[0091] S4, coaxial assembly of nozzle body assembly;

[0092] S41, tool positioning and calibration: the reference unified structure (inner core 8, annular positioning table 9) of the positioning tool is installed to the workbench of the positioner, and is fixed by the positioning pin and the workbench reference hole cooperation; the coaxiality of 6 points is detected along the outer circumference of the inner core 8 by the dial gauge, and the tool position is adjusted until the coaxiality of the inner core 8 axis and the positioner spindle axis is ≤0.01mm.

[0093] S42, inner nozzle 2 clamping and fixing: the pre-assembled inner nozzle 2 is sleeved outside the inner core 8 of the positioning tool, and the lower end face of the inner nozzle 2 abuts against the annular positioning support step 26 of the annular positioning table 9; the trapezoidal positioning blocks 15 distributed uniformly on the top of the inner core 8 are tightened, and the inner nozzle 2 is flexibly pressed by the silicone rubber pad on the inner side of the block; the radial runout of 6 points is detected along the outer circumference of the inner nozzle 2 by the dial gauge, and the radial runout is ensured to be ≤0.02mm.

[0094] S43, outer nozzle 1 installation and axial limiting: the outer nozzle 1 is sleeved outside the inner nozzle 2, and then the lower pressing ring 13 and the upper pressing ring 12 are sequentially sleeved outside the outer nozzle 1, and the upper end face of the outer nozzle 1 abuts against the lower end face of the upper pressing ring, and the outer nozzle 1 is pressed tightly to the outer side of the inner nozzle 2 by the U-shaped connecting block 131 and the first adjusting screw; the upper pressing ring 12 is sleeved from the upper end of the outer nozzle 1, and the inner hole of the upper pressing ring 12 abuts against the outer contour of the outer nozzle 1 (gap <0.02mm), until the lower end face of the upper pressing ring 12 abuts against the upper end face of the outer nozzle 1.

[0095] S44, radial gap regulation and locking: adjust the radial adjustment assembly on the positioning tool: turn the second adjustment screw clockwise, drive the pressure pawl 14 and the arc-shaped pressure block 16 (with a 0.5 mm thick silicone rubber pad) to press the upper pressure ring 12 downward; insert a feeler gauge through the inner core 8 gap detection channel to measure the radial gap at six points in real time, and gradually adjust the second adjustment screw until the gap at all points is 0-0.15 mm; lock the lock nut of the second adjustment screw to form the nozzle body assembly.

[0096] S5, laser welding of the nozzle body assembly;

[0097] S51, pretreatment before welding: polish the rib 21 butt joint area (5 mm on both sides) of the outer nozzle 1 and the inner nozzle 2 with 800# sandpaper to remove the oxide skin; wipe the area clean with acetone and blow off the residual dust with 0.4 MPa compressed air; clamp the nozzle body assembly on the positioner, and use a dial gauge to detect the circumferential runout of the outer nozzle 1, and adjust it to ≤0.15 mm.

[0098] S52, build a double-layer inert gas protection structure: install the double-layer coaxial protective cover 18 on the welding gun clamping mechanism 17 of the laser welding machine, adjust the distance between the protective cover and the outer surface of the outer nozzle 1 to 8-12 mm; seal the upper and lower ends of the nozzle body assembly, and only the lower end of the sealing ring is reserved for the argon gas inlet (connected to a high-purity argon gas supply tank 20 with a purity of ≥99.999%), and the upper end of the sealing ring is reserved for the argon gas outlet (connected to a waste gas collection pipeline); start the inert gas preheating tank 19, preheat the argon gas to 90℃, and the inlet flow is 5-8 L / min, to ensure that the argon gas covers all the back of the weld along the axial cooling flow groove 7; simultaneously adjust the protective cover gas path: the inner layer inlet flow is 18 L / min, and the outer layer inlet flow is 10 L / min, ventilate for 3-5 min to exhaust air (oxygen concentration ≤0.5%), and blow evenly to the surface of the outer nozzle 1 through the screen 25.

[0099] S53, laser welding parameter setting and welding: use a fiber laser welding machine, parameter setting: laser power 1.5 kW, welding speed 2.0 m / min, defocusing amount +3 mm, swing frequency 120 Hz, swing amplitude 0.7 mm; divide the nozzle circumference into 6 symmetrical partitions every 60°, and weld according to the "alternate diagonal partition" principle: after welding the rib 21 longitudinal joint of one partition, wait for the weld to cool down to below 200℃, and then weld the longitudinal joint of the center symmetrical partition; aim at the center line of the rib 21 through the visual positioning module during welding to ensure that the center line of the weld is offset from the center line of the rib 21 by ≤0.05 mm, and the weld penetration is 1.2 times the thickness of the outer nozzle 1 (3.6 mm).

[0100] S54. Inert atmosphere cooling: After sealing, keep the argon gas supply and the protective cover running to allow the nozzle body to cool naturally to room temperature in an inert atmosphere.

[0101] S55. Weld quality inspection: Perform penetrant testing (PT) on all longitudinal seams to meet the requirements of GB / T18851.1-2022 Class I; grind the weld edges with 1000# sandpaper until the roughness Ra≤3.2μm to form a sealed nozzle body.

[0102] S6, Assembly and welding;

[0103] S61, Collector Body Machining: Select A 35mm×1500mm seamless TA15 titanium alloy tube is bent into a circular pipe (inner diameter 35mm) using a pipe bending machine; the inner surface is precision machined on a CNC lathe until the roughness Ra≤0.8μm, ensuring that the clearance between the inner surface and the outer diameter of the outer nozzle 1 is ≤0.03mm; a 45° bevel (depth 1.5mm) is opened at the circumferential center of the outer wall of the circular pipe, where it matches the branch pipe of the tee connector, and the bevel burrs are removed.

[0104] S62. Welding of the manifold joints: Select a tee joint, a 90° elbow 6 and a flange 5 of the same material: Coaxially connect the branch pipe port of the tee joint with the bevel of the circular pipe, and perform full argon arc welding (current 120-140A, welding speed 5-6mm / s, argon flow rate 15L / min); Connect one end of the 90° elbow 6 to the main pipe port of the tee joint and the other end to the end face of the flange 5. During welding, use a right angle ruler to calibrate the perpendicularity of the flange 5 disc surface to the elbow axis ≤0.02mm; After all joint welds pass the penetrant test (PT), the inlet manifold 4 and the outlet manifold 3 are obtained.

[0105] S63. Dating and positioning of the collector and nozzle body: Clamp the nozzle body on the centering fixture of the rotary table, and calibrate the axis with the outer circle of the nozzle as the reference (runout ≤0.01mm); Connect the inlet collector 4 (upper end of the nozzle) and the outlet collector 3 (lower end of the nozzle) to both ends of the nozzle body, and ensure that the coaxiality of the collector axis and the nozzle axis is ≤0.02mm and the docking gap is ≤0.1mm by using the support mandrel.

[0106] S64. Full fillet weld: The fillet weld is performed at the joint using a pulsed argon arc welding machine. The welding area covers the "upper end face of the collector ring - outer surface of the outer nozzle 1" and the "lower end face of the collector ring - inner nozzle 2" to form a closed annular collection cavity. Argon gas with a purity of ≥99.999% (flow rate 15L / min) is continuously introduced during the welding process.

[0107] S65, weld cleaning and detection: after welding, use 1000# sandpaper to polish the edge of the butt weld to a roughness Ra≤3.2μm; use 0.5MPa compressed air to blow the current collecting cavity and axial cooling flow channel 7; perform penetration testing (PT) on all fillet welds, which meets the requirements of GB / T18851.1-2022 Grade I, forming a regenerative cooling nozzle assembly.

[0108] S7, performance verification and finished product processing;

[0109] S71, deburring and ultrasonic cleaning: use 1000# sandpaper to manually polish the welds and axial cooling flow channel 7 inlet and outlet edges of the regenerative cooling nozzle assembly to remove burrs; place it in an ultrasonic cleaning tank and use 5% neutral degreasing agent for cleaning; after cleaning, use 0.5MPa compressed air to blow the axial cooling flow channel to remove residual liquid.

[0110] S72, pressure test: using compressed air as the medium: slowly increase the pressure to 1.5 times the design pressure (30MPa) at a rate of 0.4MPa / min; hold for 30min, pressure drop ≤0.5MPa; use soap water to smear all welds, no air bubble leakage; use a dial gauge to detect the deformation of the nozzle, which is 0.08mm (≤0.1mm).

[0111] S73, liquid flow experiment: using deionized water as the medium (add 0.5% anti-rust agent): first flush the axial cooling flow channel for 7min at a flow rate of 20kg / s, then increase to 20kg / s at a rate of 5kg / s, record the pressure drop: 0.1MPa at 5kg / s, 0.15MPa at 10kg / s, 0.22MPa at 15kg / s, 0.3MPa at 20kg / s; use an industrial endoscope to detect the cross section along the flow channel axis, confirm that all channels are continuously liquid, the flow channel cross section area deviation from the design value is ≤3%, no blockage.

[0112] S74, drying: place the qualified regenerative cooling nozzle assembly into a 90℃ oven for 2h to obtain a TA15 titanium alloy regenerative cooling nozzle.

[0113] In this embodiment, the regenerative cooling nozzle processing cycle is 70 days (40% shorter than the traditional process), and the manufacturing cost is reduced by 40%; the cooling flow channel gap deviation is ≤0.02mm, the weld oxidation color grade is 1 grade; it is suitable for high temperature and high pressure working conditions of rocket engines.

[0114] Example 2: This example is for a certain type of rocket engine nozzle extension, preparing a TC4 regenerative cooling nozzle, with the following specific parameters:

[0115] Outer nozzle 1: thickness 1mm, inlet diameter 412mm, outlet diameter 1000mm (straight cylinder type), height 874mm;

[0116] Inner layer nozzle 2: thickness 1mm;

[0117] Axial cooling channel 7: number 744, depth 2mm, channel width 2.3-3.7mm;

[0118] Sealing ring: in communication with all axial cooling channels 7, ensuring uniform distribution of coolant.

[0119] The preparation steps are as follows:

[0120] S1, preparing a preformed cylinder blank;

[0121] S11, material selection and blanking: selecting 3mm thick TC4 plate (for outer layer nozzle 1) and 3mm thick TC4 plate (for inner layer nozzle 2), calculating the straight cylinder unfolding size (reserving 1.5% forming shrinkage allowance) through computer-aided design software; using numerical control laser cutting to blank into sector blanks, with plate edge roughness Ra≤1.6μm.

[0122] S12, rolling and longitudinal seam welding: placing the sector blank into a three-roll bending machine for pre-bending and then rolling into a straight cylinder blank; performing argon arc welding on the longitudinal seam, with pure argon (purity ≥99.999%, flow rate 12-15L / min) as the protective gas, and the distance between the welding gun nozzle and the weld is 5-8mm; welding parameters: current 110A, welding speed 90mm / min, arc voltage 11V; after welding, grinding the weld with 800# sandpaper to a roughness Ra≤3.2μm, and the penetration test (PT) meets the requirements of GB / T18851.1-2022 Grade I, obtaining the cylinder blank.

[0123] S13, stress relief annealing: placing the cylinder blank into a heating furnace, heating to 550℃, holding for 20min and then cooling in the furnace; after annealing, detecting the hardness of the cylinder blank to ensure that the hardness is controlled within HV 280-320, and eliminating the welding internal stress.

[0124] S14, spinning forming: placing the annealed cylinder blank into the outer side of the inner core 8 of the forming die, and positioning through the trapezoidal positioning block 15; clamping on the spinning machine workbench (coaxiality ≤0.01mm), using hot spinning process, with spinning wheel feed speed 1.5mm / s and spinning wheel pressure 60kN; after forming, detecting: outer circle roundness error of outer layer nozzle 1 ≤0.1mm, and inner hole cylindricity of inner layer nozzle 2 ≤0.03mm.

[0125] S15, inner and outer surface processing: clamping the profiled cylinder blank on the numerical control lathe: finishing the inner surface of the outer layer nozzle 1 to a roughness Ra≤1.2μm (cutting parameters: spindle speed 180 r / min, feed speed 90mm / min, back engagement amount 0.15mm), and finishing the outer surface to Ra≤1.6μm; finishing the outer surface of the inner layer nozzle 2 to Ra≤1.2μm, obtaining the preformed cylinder blank.

[0126] S2, machining axial cooling flow groove 7: clamp inner layer nozzle 2 on five-axis machining center, mill axial cooling flow groove 7 and rib 21; milling parameters: rough milling speed 2400 r / min, feed speed 200 mm / min, back engagement 1 mm, fine milling speed 3000 r / min, feed speed 120 mm / min, back engagement 0.2 mm; cooling method: oil mist cooling (concentration 60%, pressure 0.3 MPa) + 0.4 MPa compressed air blowing; after milling, detection: rib 21 width 1 mm (tolerance ± 0.03 mm), groove inner wall Ra ≤ 0.8 μm.

[0127] S3-S6, key step parameter adjustment:

[0128] S3, pre-assembly: detect inner and outer layer nozzle 1 radial gap 0-0.15 mm, end face flatness ≤ 0.03 mm.

[0129] S4, coaxial assembly: positioning tool calibration, nozzle clamping and gap control steps are the same as in example 1, only adjust the height of the down pressure ring 13 to adapt to the straight cylinder type nozzle.

[0130] S5, laser welding: double-layer coaxial protective cover 18 gas path parameters: spiral flow guide groove 24 flow 15 L / min, outer layer gas inlet 22 flow 8-12 L / min, argon preheated to 80℃; laser parameters: power 1.5 kW, welding speed 2.5 m / min, defocusing amount +3 mm, weld penetration 1.5 mm (1.5 times the thickness of the outer layer); zoned welding: divided into 24 symmetrical zones according to every 15°, and the longitudinal seam is welded alternately.

[0131] S6, collector integrated welding: collector joint welding: pulse argon arc welding current 140 A, frequency 60 Hz, weld penetration 2.5 mm (1.25 times the thickness of the branch pipe wall 2 mm); full welding of angle joint: argon flow 15 L / min, to ensure smooth transition of weld and base material.

[0132] S7, performance verification and finished product processing;

[0133] S71, deburring and cleaning: same as example 1, after ultrasonic cleaning, blow off axial cooling flow groove 7.

[0134] S72, pressure test: using compressed air as medium, pressurized to 1.5 times the design pressure (20 MPa) (30 MPa), pressure maintaining 20 min, pressure drop ≤ 0.08 MPa; soap water detection of weld has no leakage.

[0135] S73, liquid flow experiment: using deionized water as medium (adding 0.5% anti-rust agent), flushing and detecting flow channel: all channels continuously discharge liquid, cross-sectional area deviation ≤ 4%, no blockage.

[0136] S74, drying: the qualified nozzle is put into a 90℃ oven to dry for 3h, thereby obtaining a TC4 titanium alloy regenerative cooling nozzle.

[0137] Finally, it should be noted that the above examples are intended to illustrate the technical solutions of the present application but not to limit the same. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or equivalently replaced, and such modifications or equivalent replacements will not cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method of manufacturing a regeneratively cooled nozzle, characterized by: The method comprises the following steps: S1, preparing a preformed cylinder blank: first, a metal plate is made into a fan-shaped blank, then the fan-shaped blank is pre-bent by roll bending to prepare a cylinder blank, after stress relief, the inner layer nozzle and the outer layer nozzle are respectively clamped on the workbench of a spinning machine using a forming die to prepare a profiled cylinder blank, and finally the inner and outer surfaces of the profiled cylinder blank are treated to prepare the inner layer nozzle and the outer layer nozzle; The forming die comprises a reference uniform structure for clamping the cylinder blank, the reference uniform structure comprises an inner core and an annular positioning table integrally formed on the bottom circumference side of the inner core, the side of the annular positioning table away from the inner core is fixed with a base, and the top circumference of the inner core is uniformly threadedly connected with a plurality of trapezoidal positioning blocks, so as to realize the positioning and clamping of the cylinder blank on the outer side of the inner core between the annular positioning support steps of the trapezoidal positioning blocks and the annular positioning table; the profile of the inner core is consistent with the design curved generatrix contour of the regenerative cooling nozzle, and the outer contour of the inner core is fitted with the inner hole of the cylinder blank; The forming die further comprises a lower pressing ring, the lower pressing ring is sleeved on the outer side of the cylinder blank, and a plurality of U-shaped connecting blocks are uniformly arranged on the circumference side of the lower pressing ring, the plurality of U-shaped connecting blocks are connected with the base through first adjusting screws, and the lower pressing ring is used to apply axial tension to the cylinder blank to press the cylinder blank onto the inner core; the side of the trapezoidal positioning block facing the cylinder blank is bonded with a silicone rubber pad; the reference uniform structure is quenched and tempered with 45# steel; S2, processing the axial cooling flow channel: taking the inner hole of the inner layer nozzle as a reference, the forming die sleeved with the inner layer nozzle is clamped on a five-axis machining center, and the axial cooling flow channel is processed on the outer surface of the inner layer nozzle, and the adjacent two axial cooling flow channels are separated by ribs; S3, pre-assemble the outer layer nozzle and the inner layer nozzle with the axial cooling flow channel, and ensure that the radial gap and the end face flatness meet the welding requirements; S4, coaxial assembly of the nozzle main body assembly: the positioning tool is used to coaxially position the inner layer nozzle and the outer layer nozzle, and lock the radial gap to form the nozzle main body assembly; The positioning tool comprises a forming die and an upper pressing ring, the inner core of the forming die is fitted with the inner layer nozzle, the outer layer nozzle is sleeved on the outer side of the inner layer nozzle, and the outer circumference side of the outer layer nozzle is sequentially sleeved with the upper pressing ring and the lower pressing ring from top to bottom, wherein the lower pressing ring is used to apply axial tension to the outer layer nozzle to press the outer layer nozzle onto the inner layer nozzle; the upper end surface of the upper pressing ring is positioned by a plurality of radial adjusting assemblies uniformly distributed on the upper end surface of the inner core, and the convex boss axial pressing surface of the upper pressing ring is in pressure contact with the top end of the outer layer nozzle; The radial adjusting assembly comprises a second adjusting screw threadedly connected to the top end of the inner core and a pressing jaw threadedly connected with the second adjusting screw, the bottom end of the pressing jaw is integrally formed with a rear arc-shaped pressing block, and the arc-shaped pressing block is in abutment with the upper end surface of the upper pressing ring; The side of the trapezoidal positioning block facing the inner layer nozzle and the side of the arc-shaped pressing block facing the upper pressing ring are both bonded with a silicone rubber pad; Step S4 specifically comprises the following steps: S41, tool positioning and calibration: install the reference unified structure of the positioning tool to the workbench of the positioner, fix it by cooperating with the reference holes of the workbench through positioning pins; detect the coaxiality of 6 points along the outer circle of the inner core by using a micrometer, adjust the positioning tool until the coaxiality between the axis of the inner core and the axis of the main shaft of the positioner is ≤0.01mm, and ensure the accuracy of the subsequent assembly reference; S42, inner layer nozzle clamping and fixing: put the inner layer nozzle of step S3 into the outer side of the inner core of the positioning tool, so that the lower end face of the pre-assembled inner layer nozzle abuts against the annular positioning support step of the inner core; tighten the trapezoidal positioning blocks evenly distributed on the top of the inner core to realize the axial and radial positioning of the inner layer nozzle; detect the radial runout of 6 points along the outer circle of the inner layer nozzle by using a micrometer, and ensure that the radial runout is ≤0.02mm to complete the positioning of the inner layer nozzle; S43, outer layer nozzle installation and axial limiting: put the outer layer nozzle of step S3 into the outer side of the inner layer nozzle, then put the lower pressing ring into the outer side of the outer layer nozzle, and then tighten the first adjusting screw to press the outer layer nozzle to the outer side of the inner layer nozzle and make the upper end face of the outer layer nozzle fit with the step face of the upper pressing ring to limit the initial position of the outer layer nozzle in the axial direction; S44, radial gap regulation and locking: put the upper pressing ring into the outer side of the outer layer nozzle and turn the second adjusting screw, which drives the pressing claw and the arc-shaped pressing block to press the upper pressing ring downward under the cooperation of the threads; insert a feeler gauge into the gap detection channel of the inner core to measure the radial gap of 6 points of the inner layer nozzle and the outer layer nozzle, and then gradually turn the second adjusting screw until the gap of all points is ≤0.15mm, lock the second adjusting screw, and form a nozzle main body assembly; S5, laser welding of nozzle main body assembly: under the action of the double-layer coaxial protective cover, laser weld the rib longitudinal seam welding area of the outer layer nozzle and the inner layer nozzle of the nozzle main body assembly to form a sealed nozzle main body; The double-layer coaxial protective cover of step S5 is installed on the welding gun of the laser welding machine, the double-layer coaxial protective cover is provided with a main shaft through hole in the center which is matched with the spot size of the laser welding machine, and a spiral flow guide groove is arranged outside the main shaft through hole, and the outlet end of the spiral flow guide groove is flush with the lower end face of the main shaft through hole; The outer layer gas inlet and the inner layer gas inlet are sequentially arranged on the side wall of the double-layer coaxial protective cover from outside to inside and in the axial direction, both of which are inclined towards the outlet direction of the double-layer coaxial protective cover, the inlet ends of the outer layer gas inlet and the inner layer gas inlet are communicated with the inert gas preheating tank through independent pipelines, the outlet end of the inner layer gas inlet is communicated with the spiral flow guide groove, and the inert gas preheating tank is communicated with a high-purity argon gas supply tank with a purity of ≥99.999%; Both the outer layer gas inlet and the inner layer gas inlet are left with an annular air gap of 10-12mm between the main shaft, and a screen is arranged at the outlet of the double-layer coaxial protective cover; S6, integrator integrated welding: use the split metal elbow pipe to weld the tee pipe and the flange to obtain the inlet collector and the outlet collector, and then perform argon arc welding on the upper and lower ends of the nozzle main body in the form of angle joint to form a regenerative cooling nozzle assembly. S7, performance verification and finished product processing: after deburring the regenerative cooling nozzle assembly, ultrasonic cleaning with 5% neutral degreasing agent, blowing the axial cooling flow tank; performance verification by pressure test and liquid flow experiment; and the qualified regenerative cooling nozzle assembly is placed in an environment of 80-100℃ for 2-3h drying, to obtain the regenerative cooling nozzle.

2. The method of claim 1, wherein: Step S1 specifically includes the following steps: S11, material selection and blanking: select metal plate material suitable for working conditions, determine the unfolded size of the inner nozzle and the outer nozzle by computer aided design software and reserve 1.5% shrinkage allowance, use numerical control laser cutting to blank the fan-shaped blank to ensure that the plate edge roughness Ra≤1.6μm; S12, rolling and longitudinal seam welding: put the blanked fan-shaped blank into a three-roll bending machine for pre-bending, roll it into a straight cylinder blank compatible with the inner core outer contour, under the condition of pure argon gas with purity≥99.99% and flow rate of 12-15L / min, perform argon arc welding on the longitudinal seam, polish the weld transition area after welding to make the weld surface roughness Ra≤1.6μm, control the weld reinforcement at 0.3-0.5mm, and perform penetration detection to obtain the cylinder blank; S13, stress relief annealing: put the welded cylinder blank into a heating furnace for stress relief annealing to eliminate the welding internal stress; S14, spinning forming: put the annealed cylinder blank into the inner core outside of the forming die, make the lower end surface of the cylinder blank abut against the annular positioning support step on the inner core, tighten the trapezoidal positioning block at the top of the inner core to realize the axial and radial positioning of the cylinder blank, then set the lower pressing ring outside the cylinder blank, press the cylinder blank tightly to the outside of the inner core, then clamp the forming die on the spinning machine workbench and ensure the coaxiality of the cylinder blank axis and the spinning machine spindle≤0.01mm through positioning pins, open the spinning machine until the cylinder blank is formed into a contoured cylinder blank; S15, clamp the contoured cylinder blank after spinning on the numerical control lathe to process the inner and outer surfaces of the contoured cylinder blank to obtain the inner nozzle and the outer nozzle.

3. The method of claim 1, wherein: Step S5 specifically includes the following steps: S51, pretreatment before welding: polish the rib butt joint area of the outer nozzle and the inner nozzle of the nozzle body assembly with sandpaper to remove surface oxidation scale and impurities; then wipe the area clean with acetone, then blow off residual dust and waste liquid with compressed air to ensure that the welding area is free of oil stains and foreign matter; finally, clamp the treated nozzle body assembly on the positioner, detect the circular runout of 6 points along the outer circumference of the outer nozzle with a dial gauge, adjust the clamping position until the circular runout≤0.15mm; S52. Inert Gas Protection Structure Construction and Argon Coverage: Install the double-layer coaxial protective cover onto the welding torch clamping mechanism of the laser welding machine, and adjust the distance between the double-layer coaxial protective cover and the outer surface of the outer nozzle to 8-12mm; simultaneously, argon gas is introduced at a flow rate of 15-20L / min at the inner inlet and 8-12L / min at the outer inlet to form an annular gas curtain, preventing external air from diffusing into the molten pool area; at the same time, sealing rings are used to cover the upper and lower ends of the nozzle main assembly to achieve upper and lower sealing of the nozzle main assembly. The ends are sealed, and argon gas inlets and outlets are reserved on the lower and upper sealing rings. The argon gas inlet is connected to a high-purity argon gas supply tank with a purity ≥99.999%, and the argon gas outlet is connected to a waste gas collection pipe. The inert gas preheating tank is started to preheat the argon gas to 80-100℃. The preheated argon gas is introduced into the lower sealing ring through the argon gas inlet, and then evenly distributed from the lower sealing ring to the back area of ​​the weld corresponding to each axial cooling groove, ensuring that the back of each weld is covered by argon gas. S53. Laser welding parameter setting and welding: The fiber laser welding machine is used to weld according to the principle of diagonal partitioning and alternation. The circumference of the nozzle is divided into 360° / N° symmetrical partitions every N°. In each partition, one longitudinal seam is welded between the rib and the outer nozzle. After the weld of the previous partition cools down to below 200°, the longitudinal seam of the central symmetrical partition is welded to ensure that the welding stress is evenly distributed. S54. Inert atmosphere cooling: After welding, keep the argon gas supply system and double protective cover running to allow the nozzle body to cool naturally to room temperature in an inert atmosphere, avoiding oxidation of the weld seam upon contact with air. S55. Weld quality inspection: Perform penetrant testing on all welds; then grind the weld edges with sandpaper to make the roughness Ra of the weld transition area ≤ 1.6μm, forming a sealed nozzle body.

4. The method of claim 1, wherein: Step S6 specifically includes the following steps: S61. Processing of the main body of the collector: Select a seamless metal tube of the same material as the nozzle body, and bend it into a circular pipe by a pipe bending machine. The inner diameter of the circular pipe is adapted to the outer diameter of the outer nozzle, and the fitting clearance is ≤0.1mm. Clamp the circular pipe on a CNC lathe and precision machine the inner surface to a roughness Ra≤0.8μm. At the center of the outer wall of the circular pipe, a 45° bevel is opened at the matching position of the branch pipe of the tee joint. The bevel depth is 1 / 2 of the thickness of the metal pipe wall. Remove the burrs from the edge of the bevel. S62. Welding of the manifold joint: Select a tee joint, a 90° elbow, and a flange of the same material. First, coaxially connect the branch pipe port of the tee joint with the bevel of the annular pipe. Perform full argon arc welding under the condition of argon gas purity ≥99.999% and flow rate 15L / min. Then, coaxially connect one end of the 90° elbow with the main pipe port of the tee joint, and fully weld the other end to the end face of the flange. During the welding process, use a right-angle ruler to calibrate the perpendicularity of the flange face and the axis of the 90° elbow to ≤0.02mm. Then, perform a penetration test to obtain the inlet manifold and the outlet manifold. S63, the collector and the nozzle body are positioned in butt joint: the nozzle body is clamped in the centering tool of the rotary workbench, the axis of the nozzle body is calibrated by using the micrometer, and the axial runout is ensured to be less than or equal to 0.01 mm; the inlet collector and the outlet collector are respectively butt-jointed to the upper and lower ends of the nozzle body, the supporting mandrel is inserted into the inner core of the nozzle body, the coaxiality between the axis of the annular pipeline of the collector and the axis of the nozzle body is ensured to be less than or equal to 0.02 mm, meanwhile, the butt-joint gap is detected by using the feeler gauge, and the gap is ensured to be less than or equal to 0.1 mm; S64, the corner joint argon arc welding is full-welded: the butt joint part of the collector and the nozzle body is corner joint full-welded by using the pulse argon arc welding machine, and a closed annular flow collecting cavity is formed; during the welding process, the argon gas with a purity of greater than or equal to 99.999% and a flow rate of 15 L / min is continuously introduced for protection; S65, the weld is cleaned and detected: after the welding, the edge of the butt joint weld of the collector and the nozzle body is manually polished by using the sandpaper, the roughness Ra of the transition area is less than or equal to 3.2 μm; then, the flow collecting cavity and the axial cooling flow groove are blown by using the compressed air; finally, the penetration detection is performed on all the corner joint welds, and the regenerative cooling nozzle assembly is formed.

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