Welding method for thin-wall stainless steel skin heat insulation tile connecting structure

Abstract

The invention provides a thin-wall stainless steel skin heat insulation tile connecting structure welding method which comprises the following steps: marking a welding area and a welding sequence by marking a connecting piece distribution position of a to-be-welded area of a skin; according to the marked welding area and the welding sequence, the to-be-welded part is welded to the target position through a short-period and balanced magnetic field stud welding method; and after welding is completed, welding spot detection and air tightness detection are conducted on the skin welding seam area. High-quality and high-efficiency welding connection of rocket thin-wall stainless steel skin heat insulation tile metal structures repeatedly used in China can be achieved, the equipment investment cost is low, the welding technical problems of guaranteeing the welding strength of thin-wall stainless steel skin heat insulation tile structural parts and precisely controlling weld penetration are solved, and the technical blank of product development is filled.

Description

Technical Field

[0001] This application belongs to the field of rocket skin welding technology, and particularly relates to a welding method for a thin-walled stainless steel skin heat insulation tile connection structure. Background Technology

[0002] In recent years, reusable rocket technology has developed rapidly. To meet the demands of low-cost, high-efficiency space travel, stainless steel is used as the material for the rocket's skin structure. To address the heat insulation issue during atmospheric flight, a heat-insulating tile structure is required on the outer surface. The design uses metal connectors to attach these heat-insulating tiles to the stainless steel skin. These metal connectors are typically made of the same stainless steel as the skin. Due to the thinness of the skin structure (1.6-2mm), welding the metal connectors requires meeting both connection strength requirements and precise control of weld penetration to prevent skin deformation and burn-through. Furthermore, high welding position accuracy is also necessary, presenting significant technical challenges.

[0003] Currently, there is no welding technology or method for thin-walled stainless steel skin heat insulation tile structures in China, leaving a gap in this area. Summary of the Invention

[0004] In view of this, this application aims to propose a welding method for the connection structure of thin-walled stainless steel skin heat insulation tiles, so as to solve the welding technical problem of ensuring the welding strength and accurately controlling the weld penetration of special metal structural parts on thin-walled stainless steel skin with a thickness of 1.6-2mm.

[0005] To achieve the above objectives, the technical solution of this application is implemented as follows: This application provides a welding method for a thin-walled stainless steel skin heat insulation tile connection structure, including: By marking the locations of the connectors in the skin's welding area, the welding areas and welding sequence are indicated. According to the marked welding area and welding sequence, the parts to be welded are welded to the target position using a short-cycle stud welding method with a balanced magnetic field. After welding is completed, weld spot inspection and airtightness inspection are carried out on the skin weld area.

[0006] Furthermore, before marking the welding area and welding sequence, it also includes: Clean the surface of the skin to be welded and perform ultrasonic thickness measurement on the area of ​​the skin to be welded to record the actual thickness value and deviation.

[0007] Furthermore, the welding sequence adopts a symmetrical cross welding pattern.

[0008] Furthermore, the parts to be welded are mounted on the welding head, and short-circuit positioning is achieved through the vertical movement of the head and contact with the skin. By connecting the auxiliary power supply, a preliminary current is provided to the parts to be welded, and an arc space is formed after the arc is ignited. By switching on the welding current and forming a welding arc, and adding a balanced magnetic field around the stud welding arc to make the welding arc rotate at high speed, the welding arc concentrates the melting of the end of the part to be welded and the skin surface at a given time, and the molten metal at the end face of the stud is uniformly transferred to the plate surface to form a uniform weld.

[0009] Furthermore, the weld point inspection uses X-ray flaw detection to detect internal defects in the weld.

[0010] Furthermore, the skin welding area was inspected using a vacuum helium mass spectrometry leak detection method.

[0011] Furthermore, the stud diameter is determined by setting the matching relationship between the stud diameter and the plate thickness. The relationship between the stud diameter and the plate thickness is as follows: stud diameter D / plate thickness δ≤5.

[0012] Furthermore, the formula for determining the welding time is as follows: ; In the formula, The diameter of the stud is in mm. This indicates the welding time, in milliseconds (ms).

[0013] Compared with the prior art, the welding method for the connection structure of thin-walled stainless steel skin heat insulation tile described in this application has the following advantages: The welding method for the connection structure of thin-walled stainless steel skin heat insulation tile described in this application can achieve high-quality and high-efficiency welding connection of the metal structure of thin-walled stainless steel skin heat insulation tile for reusable rockets in China. It has low equipment investment cost, solves the welding technology problem of ensuring welding strength and precise control of weld penetration of thin-walled stainless steel skin heat insulation tile structural components, and fills the gap in product development technology. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram illustrating the welding position and sequence planning described in the embodiments of this application; Figure 2 This is a schematic diagram of the welding process of the heat insulation tile connection structure described in the embodiments of this application; Figure 3 This is a schematic diagram illustrating the welding shrinkage angle caused by arc blow as described in the embodiments of this application; Figure 4 This is a schematic diagram of the stud welding process using a balanced magnetic field mode as described in the embodiments of this application. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0016] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0017] As described in the background section above, this application aims to address two core issues: first, to solve the welding technology challenges of ensuring welding strength and precisely controlling weld penetration at the connection points of special metal structural components on thin-walled stainless steel skins with a thickness of 1.6-2mm; and second, to solve the technical challenges of high-efficiency welding and deformation control for densely connected structural components on large thin-walled stainless steel skins.

[0018] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0019] This embodiment provides a welding method for a thin-walled stainless steel skin heat insulation tile connection structure, which specifically includes the following steps: Step S101: Pre-welding preparation.

[0020] Clean the surface of the skin to be welded, removing oil, water stains, and other excess material to ensure the welding area is clean; perform ultrasonic thickness measurement on the area of ​​the skin to be welded, and record the actual thickness value and deviation.

[0021] Step S102: Planning of welding positions and welding sequence. Mark the locations of the connectors, indicating the welding areas and sequence. A symmetrical, cross-welding pattern is used to control welding deformation. The welding positions and sequence are as follows: Figure 1 As shown.

[0022] Step S103: Welding of the studs connecting the heat insulation tiles on the stainless steel skin.

[0023] For 1.6mm-2mm stainless steel skin, a short-cycle stud welding method with a balanced magnetic field is used to achieve the welded connection of the structure. First, the parts to be welded are mounted on the welding head. The vertical movement of the head contacts the skin, forming a short-circuit positioning. Second, the auxiliary power supply is turned on, providing a pilot current of 30-50A to the parts. This pilot arc cleans the welding surface, decomposing residual oil, oxides, and coatings at high temperatures and releasing them into the arc space. Third, the welding current is turned on, forming a welding arc. The welding arc concentrates the melting of the end of the parts to be welded and the surface of the skin. After a given time, the joint clamp holds the parts to be welded and lowers them into the molten pool under the pressure of the welding torch spring. After a delay, the current is cut off, and the welding ends. The welding process is as follows: Figure 2 As shown.

[0024] Step S104: Solder joint inspection.

[0025] X-ray flaw detection is used to detect internal defects in welds and eliminate defects such as cracks, lack of fusion, and incomplete penetration.

[0026] Step S105: Air tightness test of the skin weld area.

[0027] Vacuum helium mass spectrometry was used to perform helium leak detection on the welded areas of the skin to avoid the potential risk of localized burn-through in thin-walled skin.

[0028] In this embodiment, a short-cycle stud welding method for thin-walled stainless steel skin under a balanced magnetic field mode was developed to address the specific characteristics of the product structure and usage requirements, effectively ensuring the welding quality of the product.

[0029] In response to the stringent requirements for weld penetration in thin stainless steel sheets, a short-cycle stud welding parameter system was developed.

[0030] A. Matching the stud diameter and plate thickness: Determine the stud diameter M6-M8 according to the rule that stud diameter D / plate thickness δ≤5; B. Welding time: ,in, The diameter of the stud is in mm. (unit: milliseconds) is used to determine the welding time; C. Welding current: ,in, The diameter of the stud is in mm. (Unit A) Determine the welding current; D. Lifting height: proportional to the stud diameter, ranging from 1.2 to 1.5 mm.

[0031] This embodiment uses a balanced magnetic field mode to control arc blow during the welding process.

[0032] like Figure 3As shown, during conventional stud welding, the instantaneous high current generates a strong magnetic field, and the airflow generated by the overheated air and ceramic ring also affects the electric arc. Both of these factors can cause the electric arc to deviate along the stud axis, resulting in arc blow. As a result, the welded part melts on one side, and after upsetting, it deviates due to the asymmetry of thermal expansion and contraction, which seriously affects the welding quality and positional dimensions.

[0033] To solve the problem of arc blow, such as Figure 4 As shown, this embodiment proposes a thin-walled stainless steel stud welding method using a balanced magnetic field mode. The welding equipment adds a controllable magnetic field around the stud welding arc, causing the arc to rotate at high speed. This uniformly transfers the molten metal from the stud end face to the plate surface, forming a uniform weld. The high arc stiffness effectively controls arc deviation, achieving uniform circumferential penetration of the weld. Simultaneously, the arc rotation and uniform metal transfer reduce welding heat input, effectively minimizing workpiece deformation, shortening welding time, reducing energy loss by 70%, and significantly improving production efficiency.

[0034] The welding method for the connection structure of thin-walled stainless steel skin heat insulation tile provided in this embodiment can realize high-quality and high-efficiency welding connection of the metal structure of thin-walled stainless steel skin heat insulation tile for reusable rockets in China. It has low equipment investment cost, solves the welding technology problem of ensuring welding strength and precise control of weld penetration of thin-walled stainless steel skin heat insulation tile structural components, and fills the gap in product development technology.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

[0036] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A welding method for a connection structure of a thin-walled stainless steel skin heat insulation tile, characterized in that, include: By marking the locations of the connectors in the skin's welding area, the welding areas and welding sequence are indicated. According to the marked welding area and welding sequence, the parts to be welded are welded to the target position using a short-cycle stud welding method with a balanced magnetic field. After welding is completed, weld spot inspection and airtightness inspection are carried out on the skin weld area.

2. The method according to claim 1, characterized in that, Before marking the welding areas and welding sequence, the following is also included: Clean the surface of the skin to be welded and perform ultrasonic thickness measurement on the area of ​​the skin to be welded to record the actual thickness value and deviation.

3. The method according to claim 1, characterized in that: The welding sequence adopts a symmetrical cross welding pattern.

4. The method according to claim 1, characterized in that: The parts to be welded are mounted on the welding head, and short-circuit positioning is achieved through the vertical movement of the head and contact with the skin. By connecting the auxiliary power supply, a preliminary current is provided to the parts to be welded, and an arc space is formed after the arc is ignited. By switching on the welding current and forming a welding arc, and adding a balanced magnetic field around the stud welding arc to make the welding arc rotate at high speed, the welding arc concentrates the melting of the end of the part to be welded and the skin surface at a given time, and the molten metal at the end face of the stud is uniformly transferred to the plate surface to form a uniform weld.

5. The method according to claim 1, characterized in that: The weld point inspection uses X-ray flaw detection to detect internal defects in the weld.

6. The method according to claim 1, characterized in that: The welded area of ​​the skin was inspected using a vacuum helium mass spectrometry leak detection method.

7. The method according to claim 1, characterized in that: The stud diameter is determined by setting the matching relationship between the stud diameter and the plate thickness. The relationship between the stud diameter and the plate thickness is as follows: stud diameter D / plate thickness δ≤5.

8. The method according to claim 1, characterized in that, The formula for determining the welding time is as follows: ； In the formula, The diameter of the stud is in mm. This indicates the welding time, in milliseconds (ms).

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