A rocket tank bottom heat treatment method and tooling

Abstract

The present invention provides a method for heat treatment of the bottom of a rocket tank, comprising the following steps: S1, spray quenching test on a test workpiece, and dividing a number of processing areas according to the diameter shrinkage of different positions of the test workpiece; S2, determining the processing procedure of the annular processing area according to the type of the tank bottom; S3, spray quenching treatment according to the processing procedure determined in S2. The present invention controls the cooling and shrinkage sequence of different areas of the tank bottom through reasonable quenching procedures and process parameters based on the cooling characteristics of spray quenching and the structural stiffness characteristics of the tank bottom, so that the shrinkage deformation of the tank bottom accumulates to a position with a large margin, and uses tooling to shape the straight section area, so that the deformation of the tank bottom heat treatment is controllable, ensuring that the deformation degree of the difficult-to-process area at the large end of the tank bottom after quenching is less than 0.3%, filling the technical gap in the heat treatment method for the tank bottom after overall forming.

Description

Technical Field

[0001] The invention belongs to the field of launch vehicle parts processing, and in particular relates to a rocket tank bottom heat treatment method and tooling. Background Art

[0002] The launch vehicle tank is used as a pressure vessel to store propellants. It is also the main load-bearing structure of the launch vehicle and a key component of the launch vehicle. The tank bottom is a head-end product, and its product reliability and lightweight index directly affect the safety and reliability of the tank. The traditional tank bottom is made of multiple melon slices welded together, and the weld thickness needs to be increased to supplement the insufficient strength, which restricts the further improvement of the tank lightweight index; at the same time, the melon slice welded tank bottom process is complicated and the production cycle is long, which limits the production capacity and economy of the launch vehicle. Therefore, the new generation of medium-sized launch vehicles began to adopt the integral spinning tank bottom. However, the research and manufacturing of the integral spinning of the tank bottom in China is still in its infancy, and the research and application of the heat treatment shape control technology after the integral forming of the tank bottom is still blank. Summary of the invention

[0003] In view of this, the present invention aims to propose a rocket tank bottom heat treatment method and tooling to solve the above-mentioned technical problems.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] The present invention provides a rocket tank bottom heat treatment tool, comprising a base frame, an annular inner support and a plurality of fixing components, wherein the annular inner support is installed on the base frame, and the outer side of the annular inner support abuts against the inner wall of the tank bottom to form support for the tank bottom on the inner side; the fixing components are arranged at intervals along the circumferential direction on the outer side of the annular inner support to fix the opening edge of the tank bottom.

[0006] Furthermore, the annular inner support includes an inner ring and an outer ring, the inner ring and the outer ring are coaxially mounted on the base frame, and the outer ring has a larger diameter than the inner ring; a plurality of radially distributed horizontal beams are fixed between the outer ring and the inner ring to increase the strength of the annular inner support.

[0007] Further, the fixing component includes a fixing seat, a lifting device, a first clamping member and a pair of second clamping members, the fixing seat is fixed to the outer edge of the base frame by the first clamping member and the second clamping member; the lifting device is installed on the fixing seat, and the outer edge of the base frame is provided with an avoidance groove for avoiding the lifting end of the lifting device; the lifting end of the lifting device is provided with a clamping groove, and the edge of the bottom of the box is clamped in the clamping groove for fixing;

[0008] The first clamping member is clamped on the outer edge of the base frame; the first clamping member includes a first clamping plate and a first screw, the first clamping plate is mounted on the top end of the first screw, and the bottom end of the first screw is fixed on the fixing seat;

[0009] The second clamp is mounted on the edge of the base frame; the second clamp includes a second clamp plate and a second screw rod, the bottom end of the second screw rod is slidably mounted in the T-slot at the top of the fixing seat through a slider, and the second clamp plate is mounted on the top end.

[0010] The present invention provides a rocket tank bottom heat treatment method, comprising the following steps:

[0011] S1. Perform a spray quenching test on the test workpiece and divide it into several processing areas according to the diameter shrinkage of different positions of the test workpiece;

[0012] S2. Determine the processing procedure of the annular processing area according to the type of the bottom of the box;

[0013] S3. Perform spray quenching treatment according to the treatment process determined in S2.

[0014] Furthermore, in S1, the annular processing area includes a top cover area, a circular ring area, a fork ring area and a straight line segment area.

[0015] Further, in S2, the method for determining the processing procedure is:

[0016] S21, judging whether there is a bottom hole at the bottom of the box;

[0017] S22. If there is a bottom hole at the bottom of the box, spray the forked ring area, the circular ring area, and the top cover area in order, wherein the spraying of the circular ring area is 3-5s apart from that of the forked ring area;

[0018] If there is no bottom hole at the bottom of the box, spraying will be carried out in the order of the fork ring area, the top cover area and the circular ring area. The spraying of the top cover area is 3-5s apart from that of the fork ring area, and the spraying of the circular ring area is 3-5s apart from that of the top cover area.

[0019] Furthermore, in S3, the sum of the quenching time of each area is less than or equal to the difference between the maximum quenching transfer time and the actual transfer time of the bottom of the box.

[0020] Furthermore, the maximum quenching transfer time is 15-40s.

[0021] Furthermore, in S3, the deformation of the straight section area of ​​the box bottom is compensated by the method of spinning and expanding the volume, and the spinning trajectory is a gradual opening type; if the box bottom is a box bottom without a bottom hole, it is also necessary to use a tooling to fix the large end of the box bottom.

[0022] Furthermore, the deviation degree B of the straight line segment area is calculated according to the following formula:

[0023] B = kI + b;

[0024] Among them, B is the degree of deviation, I is the straightness length, k is the proportionality coefficient, and b is the initial degree of deviation;

[0025] The degree of deviation of the end position of the straight segment area is determined according to the shrinkage after spinning, and the calculation formula is as follows:

[0026] B = α × D × (K1-K2);

[0027] Among them, α is the thermal expansion coefficient of the material, D is the product diameter, K1 is the heating temperature, and K2 is the room temperature.

[0028] Compared with the prior art, the rocket tank bottom heat treatment method and tooling described in the present invention have the following beneficial effects:

[0029] The rocket tank bottom heat treatment method provided by the present invention is based on the spray quenching cooling characteristics, combined with the structural stiffness characteristics of the tank bottom, through reasonable quenching procedures and process parameters, to control the cooling and shrinkage sequence of different areas of the tank bottom, so that the shrinkage deformation of the tank bottom is accumulated to a position with a large margin, and the straight section area is finalized by tooling to achieve controllable deformation of the tank bottom during heat treatment, ensuring that the deformation degree of the difficult-to-process area at the large end of the tank bottom after quenching is less than 0.3%, filling the technical gap in the heat treatment method for the tank bottom after overall forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 It is a schematic diagram of the overall structure of the rocket tank bottom heat treatment tooling of the present invention;

[0032] Figure 2 For the present invention Figure 1 A partial enlarged view of the middle A part;

[0033] Figure 3 is a flow chart of the method of the present invention;

[0034] Figure 4 This is a schematic diagram of the covering position of the spray quenching furnace of the present invention;

[0035] Figure 5 This is a schematic diagram of the area division of the box bottom of the present invention;

[0036] Figure 6 This is a schematic diagram of setting the straight line segment area deviation rate of the present invention.

[0037] Description of reference numerals:

[0038] 1-annular inner support; 11-outer ring; 12-inner ring; 13-horizontal beam; 2-base; 3-fixed component; 31-first clamp; 311-first clamp plate; 312-first screw; 32-fixed seat; 321-T-slot; 33-lifting device; 331-slot; 34-second clamp; 341-second clamp plate; 342-second screw; 343-slider. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0043] The present invention provides a rocket tank bottom heat treatment tool, comprising a base frame 2, an annular inner support 1 and a plurality of fixing components 3. The annular inner support 1 is installed on the base frame 2, and the outer side of the annular inner support 1 is against the inner wall of the tank bottom, which is used to form support for the tank bottom on the inner side; the fixing components 3 are arranged in compartments along the circumferential direction on the outer side of the annular inner support 1, which is used to fix the edge of the tank bottom opening.

[0044] The annular inner support 1 includes an inner ring 12 and an outer ring 11, and the inner ring 12 and the outer ring 11 are coaxially mounted on the base frame 2, and the outer ring 11 has a larger diameter than the inner ring 12; a plurality of radially distributed horizontal beams 13 are fixedly installed between the outer ring 11 and the inner ring 12 to improve the strength of the annular inner support 1.

[0045] The fixing component 3 includes a fixing seat 32, a lifting device 33, a first clamp 31 and a pair of second clamps 34. The fixing seat 32 is fixed to the outer edge of the base frame 2 through the first clamp 31 and the second clamp 34. The lifting device 33 is installed on the fixing seat 32. The outer edge of the base frame 2 is provided with an avoidance groove for avoiding the lifting end of the lifting device 33. The lifting end of the lifting device 33 is provided with a clamping groove 331, and the edge of the bottom of the box is clamped in the clamping groove 331 for fixing. Specifically, the lifting device 33 is a jack. The first clamp 31 is clamped on the outer edge of the base frame 2. The first clamp 31 includes a first clamping plate 311 and a first screw 312. The first clamping plate 311 is installed on the top of the first screw 312, and the bottom of the first screw 312 is fixed on the fixing seat 32. The second clamping member 34 is clamped on the edge of the base frame 2; the second clamping member 34 includes a second clamping plate 341 and a second screw 342, the bottom end of the second screw 342 is slidably installed in the T-slot 321 at the top of the fixing seat 32 through a slider 343, and the second clamping plate 341 is installed on the top.

[0046] The present invention provides a rocket tank bottom heat treatment method, which specifically comprises the following steps:

[0047] S1. Perform a spray quenching test on the test workpiece and divide it into several processing areas according to the diameter shrinkage of different positions of the test workpiece;

[0048] The annular processing area includes a top cover area, a circular ring area, a fork ring area and a straight line segment area. Figure 5 As shown in the figure, according to the preliminary spray test results, there is diameter shrinkage in different areas of the box bottom after spray quenching. The distribution pattern is that the diameter shrinkage after quenching gradually increases from the top cover area to the straight section area, and the position with the minimum machining allowance is located in the fork ring area and the straight section area.

[0049] S2. Determine the processing procedure of the annular processing area according to the type of the bottom of the box;

[0050] Among them, the method for determining the processing procedure is:

[0051] S21. Determine whether there is a bottom hole at the bottom of the box.

[0052] S22. The rigidity of the bottom structure gradually decreases from the top cover to the fork-shaped ring area, and spraying needs to be performed in the order of rigidity from small to large. For the bottom of the box with a bottom hole, the machining allowance of the fork-shaped ring area is small, and the machining allowance of the top cover area is the largest. The quenching deformation needs to be gradually accumulated to the top cover area. Therefore, spraying needs to be performed in the order of the fork-shaped ring area, the circular ring area, and the top cover area. Among them, the spraying of the circular ring area is 3-5s apart from that of the fork-shaped ring area.

[0053] For the box bottom without bottom holes, the machining allowance of the fork ring area is smaller, and the machining allowance of the circular ring area is the largest. The quenching deformation of the top cover area and the fork ring area needs to be accumulated to the circular ring area. Therefore, it is necessary to spray in the order of the fork ring area, the top cover area, and the circular ring area. Among them, the spraying of the top cover area is 3-5s away from the fork ring area, and the spraying of the circular ring area is 3-5s away from the top cover area.

[0054] The bottom of the box without bottom holes is a semi-closed cavity structure. The traditional invasive quenching method cannot solve the exhaust problem at the top of the box bottom. A closed air cavity is formed at the bottom of the box, which causes the box to easily deform greatly during the quenching process. The heat treatment method provided by the present invention uses spray quenching instead of traditional invasive quenching. Through a reasonable spraying sequence, the cooling and shrinking sequence of different positions of the box bottom is controlled, so that the shrinkage deformation of the box bottom accumulates to a position with a large margin, thereby minimizing the degree of heat treatment deformation of the box bottom.

[0055] S3, performing spray quenching treatment according to the treatment process determined in S2;

[0056] The sum of the quenching time of each area is less than or equal to the difference between the maximum quenching transfer time and the actual transfer time of the bottom of the box. Preferably, the maximum quenching transfer time is 15-40s.

[0057] The spinning method is adopted to compensate for the deformation of the straight line area at the bottom of the box, and the spinning trajectory is an involute type;

[0058] The deviation degree B of the straight line segment area is calculated according to the following formula:

[0059] B = kI + b;

[0060] Among them, B is the degree of deviation, I is the straightness length, k is the proportionality coefficient, and b is the initial degree of deviation;

[0061] The degree of deviation of the end position of the straight segment area is determined according to the shrinkage after spinning, and the calculation formula is as follows:

[0062] B = α × D × (K1-K2);

[0063] Among them, α is the thermal expansion coefficient of the material, D is the product diameter, K1 is the heating temperature, and K2 is the room temperature.

[0064] If the bottom of the box is a bottomless box, the deformation of the bottom of the box will accumulate from the upper and lower ends to the annular area. After quenching, the shrinkage deformation of the annular area will be further transmitted to the large end and cause local elastic deformation of the large end. Therefore, it is also necessary to use a tool to fix the large end of the box bottom. Place the large end of the box bottom facing down on the heat treatment tooling of the bottom of the rocket tank, fix the bottom of the box with the fixing component 3, and the edge of the box bottom is clamped in the slot 331 at the top of the lifting device 33. Drive it to a suitable height through the lifting device 33 to ensure that the annular inner support 1 covers the straight section area. At the same time, it is necessary to avoid the annular inner support 1 from contacting the annular area to avoid excessive shrinkage of the box bottom during quenching, which may cause deformation of the tooling.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A rocket tank bottom heat treatment method, characterized in that: The following steps are involved: S1. Perform a spray quenching test on the test workpiece and divide it into several processing areas according to the diameter shrinkage of different positions of the test workpiece; S2. Determine the processing procedure of the annular processing area according to the type of the bottom of the box; S3, performing spray quenching treatment according to the treatment process determined in S2; In S1, the processing area includes a top cover area, a circular ring area, a fork ring area and a straight line segment area; In S2, the method for determining the processing steps is: S21, judging whether there is a bottom hole at the bottom of the box; S22. If there is a bottom hole at the bottom of the box, spray the forked ring area, the circular ring area, and the top cover area in order, wherein the spraying of the circular ring area is 3-5s apart from that of the forked ring area; If there is no bottom hole at the bottom of the box, spraying will be carried out in the order of the fork ring area, the top cover area and the circular ring area. The spraying of the top cover area is 3-5s apart from that of the fork ring area, and the spraying of the circular ring area is 3-5s apart from that of the top cover area.

2. The heat treatment method according to claim 1, characterized in that In S3, the sum of the quenching time of each area is less than or equal to the difference between the maximum quenching transfer time and the actual transfer time of the bottom of the box.

3. The heat treatment method according to claim 2, characterized in that: The maximum quenching transfer time is 15-40s.

4. The rocket tank bottom heat treatment method according to any one of claims 1 to 3, characterized in that: A rocket tank bottom heat treatment tool is used, which includes a base frame, an annular inner support and a plurality of fixing components. The annular inner support is installed on the base frame, and the outer side of the annular inner support is against the inner wall of the tank bottom to form support for the tank bottom on the inner side; the fixing components are arranged in compartments along the circumferential direction on the outer side of the annular inner support to fix the opening edge of the tank bottom.

5. The rocket tank bottom heat treatment method according to claim 4, characterized in that: The annular inner support includes an inner ring and an outer ring, which are coaxially mounted on the base frame, and the outer ring has a larger diameter than the inner ring. A plurality of radially distributed horizontal beams are fixed between the outer ring and the inner ring to improve the strength of the annular inner support.

6. The rocket tank bottom heat treatment method according to claim 4, characterized in that: The fixing component comprises a fixing seat, a lifting device, a first clamping member and a pair of second clamping members, wherein the fixing seat is fixed to the outer edge of the base frame by the first clamping member and the second clamping member; the lifting device is installed on the fixing seat, and the outer edge of the base frame is provided with an avoidance groove for avoiding the lifting end of the lifting device; the lifting end of the lifting device is provided with a clamping groove, and the edge of the bottom of the box is clamped in the clamping groove for fixing; The first clamping member is clamped on the outer edge of the base frame; the first clamping member includes a first clamping plate and a first screw, the first clamping plate is mounted on the top end of the first screw, and the bottom end of the first screw is fixed on the fixing seat; The second clamp is mounted on the edge of the base frame; the second clamp includes a second clamp plate and a second screw rod, the bottom end of the second screw rod is slidably mounted in the T-slot at the top of the fixing seat through a slider, and the second clamp plate is mounted on the top end.

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