A method for manufacturing a large thin-walled titanium alloy frame structure

Abstract

The application provides a preparation method of a large thin-wall titanium alloy frame structure, which comprises the following steps: S1, product analysis and classification; S2, production of parts; S3, preparation of a platform and a tool; and S4, layer-by-layer assembly welding. The preparation method of the large thin-wall titanium alloy frame structure can realize production of the large thin-wall titanium alloy frame structure under the premise that the shape and size of the product are not limited, and can meet the high-precision requirement of the product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of titanium alloy processing, in particular to a preparation method of a large thin-walled titanium alloy frame structure. BACKGROUND

[0002] Titanium alloy has excellent comprehensive performance such as small density, high specific strength, corrosion resistance, and non-magneticity, and has become an important structural material in the field of high-end equipment. With the rapid development of China's shipbuilding, aviation, aerospace and other fields, the demand for high performance and high precision of related supporting equipment has made titanium alloy castings develop towards integration, large size and complexity. In particular, there is an increasing demand for large titanium alloy frame castings in aerospace equipment, which requires larger size and lighter weight.

[0003] Due to the size of the existing casting furnace equipment and the difficulty of filling the thin-walled titanium alloy, the size of the large thin-walled titanium alloy frame casting is generally less than 3000mm, and the casting wall thickness is generally greater than or equal to 5mm. Among them, the applicant uses machining graphite mold casting process to develop a complex frame titanium alloy casting for aerospace with a maximum size of 2300mm, and the minimum wall thickness is 5mm; Shenyang Casting Research Institute currently has the largest 1200kg vacuum consumable arc skull furnace in China, and the size of the investment casting large titanium alloy casting developed by the institute reaches more than 2000mm, and the minimum wall thickness is 3mm.

[0004] However, the frame structure with larger size and thinner wall thickness cannot be casted in the prior art. SUMMARY

[0005] Therefore, the present application aims to solve the technical problem of providing a preparation method of a large thin-walled titanium alloy frame structure, which realizes the production of a large thin-walled titanium alloy frame structure without limiting the shape and size of the product, and meets the high precision requirement of the product.

[0006] To solve the above technical problems, the present application provides a preparation method of a large thin-walled titanium alloy frame structure, comprising the following steps:

[0007] S1: product analysis and classification;

[0008] S2: production of parts;

[0009] S3: making platform and tooling;

[0010] S4: layer-by-layer assembly welding.

[0011] Preferably, step S1 comprises the following specific analysis steps:

[0012] S11: analyzing the shape and structure of the product;

[0013] S12: dividing the product into multiple layers and support connecting members between the multiple layers according to the product space structure;

[0014] S13: classifying and separating all parts in the product according to different shapes and structures.

[0015] Preferably, the classified and separated results of step S13 include "thin-walled pipes, special-shaped structural members" or "thin-walled pipes, special-shaped structural members, and plates".

[0016] Preferably, step S2 includes at least the first two or all of the following production processes:

[0017] S21: producing special-shaped structural members by using the investment precision casting or machining graphite mold casting process;

[0018] S22: forming thin-walled pipes by using seamless pipes or welded pipes;

[0019] S23: forming plates by using hot rolling or cold rolling processes.

[0020] Preferably, step S3 includes the following specific manufacturing steps:

[0021] S31: manufacturing a special large welding platform to ensure that the welding platform is flat and meets the flatness requirements;

[0022] S32: manufacturing a tool for group welding.

[0023] Preferably, in step S32, the tool includes at least a support tool, a fixing tool, and a deformation prevention tool.

[0024] Preferably, step S4 includes the following layer-by-layer group welding steps:

[0025] S41: bottom layer group welding, finding a reference and supporting and fixing by using a tool, positioning the positions of corresponding parts, and then performing spot welding, size re-measurement, and full welding;

[0026] S42: sequentially completing the individual group welding of all other layers;

[0027] S43: performing overall group welding from bottom to top by using corresponding support connecting members.

[0028] Preferably, step S43 includes the following overall group welding steps:

[0029] S431: adjusting the distances and angles between layers by using a support tool;

[0030] S432: determining the positions of corresponding structures by using a laser positioner;

[0031] S433: welding from inside to outside until the product is fully welded;

[0032] S434: Ensure product size tolerance by detection and adjustment.

[0033] Preferably, in step S431, the planar surface of the bottom layer support tool corresponding to the bottom layer group welding is taken as the reference surface, and the support tools of other layers are adjusted according to the difference value.

[0034] Preferably, when the special-shaped structural member comprises a large outer circular I-beam, the large outer circular I-beam is segmented and formed by adopting the graphite mold casting process in step S21, and before step S41, step S4 further comprises the following layer-by-layer group welding steps:

[0035] S40: Group welding of the large outer circular I-beam, taking the outer circle as the reference, the segmented outer circular I-beam is fixed and compacted on the welding platform by the tool, and after spot welding, the size precision is detected and adjusted, and then full welding is performed.

[0036] Compared with the prior art, the preparation method of the large thin-walled titanium alloy frame structure member has the following beneficial effects:

[0037] 1) The production of the large thin-walled titanium alloy frame structure member is realized under the premise that the shape and size of the product are not limited, and the high-precision requirement of the product is met;

[0038] 2) The large thin-walled titanium alloy frame structure member is prepared by combining "casting, rolling, machining, and layer-by-layer group welding", so as to overcome the shortcoming that the existing casting furnace cannot directly cast the large thin-walled frame product. BRIEF DESCRIPTION OF DRAWINGS

[0039] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification. The illustrations are shown to explain the present application and are not intended to be an improper limitation of the present application. In the drawings:

[0040] Figure 1 FIG. 1 is a first perspective view of a large thin-walled titanium alloy frame structure member according to the present application;

[0041] Figure 2 FIG. 2 is a second perspective view of a large thin-walled titanium alloy frame structure member according to the present application;

[0042] Figure 3 FIG. 3 is a perspective view of a bottom layer group welding according to the present application;

[0043] Figure 4 FIG. 4 is a perspective view of an outer circular I-beam according to the present application; Figure 3

[0044] Figure 5 ​A planar structure schematic view of a sectional pouring mold (for an outer circle I-beam) according to the present application;

[0045] Figure 6 A three-dimensional structure schematic view of an upper layer assembly welding according to the present application. DETAILED DESCRIPTION

[0046] In order to make the above-mentioned objectives, technical solutions and advantages of the present application more clear and easy to understand, the present application will be further described in detail below. It should be understood that the specific embodiments described herein of the present application are only part of the embodiments of the present application, which are only used to explain the present application and do not constitute a limitation of the present application. In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0047] Referring to Figures 1-6 The present application proposes a preparation method of a large thin-walled titanium alloy frame structure, comprising the following steps:

[0048] S1: product analysis and classification;

[0049] S2: production of parts;

[0050] S3: making platform and tooling;

[0051] S4: layer-by-layer assembly welding.

[0052] Specifically, referring to Figures 1-2 It is a three-dimensional structure schematic view of a large thin-walled titanium alloy frame structure. In the present application, in view of the shortcomings of the existing process method, the large thin-walled titanium alloy frame structure can be prepared by the method of "product analysis and classification - production of parts - making platform and tooling - layer-by-layer assembly welding", so as to overcome the shortcomings that the existing casting furnace cannot directly cast the large thin-walled frame product. Thus, under the premise that the shape and size of the product are not limited, the production of the large thin-walled titanium alloy frame structure is realized, and the high-precision requirement of the product is met.

[0053] Preferably, step S1 comprises the following specific analysis steps:

[0054] S11: analyzing the shape structure of the product;

[0055] S12: dividing the product into multiple layers and support connecting pieces located between the multiple layers according to the spatial structure of the product;

[0056] S13: classifying and splitting all parts in the product according to the different shape structures.

[0057] Specifically, the large frame structure has large size, thin wall, and many small structures, which cannot be directly casted into shape, and needs to be divided into multiple layers according to the spatial structure of the product, and the parts in the product are classified and split according to the different shapes and structures, such as thin-walled pipes, special-shaped structural parts, and plates. Therefore, in step S2, other more diversified production processes can be adopted according to the different shapes and structures of the parts, such as rolling, machining, etc., without being limited to the casting process; meanwhile, in step S4, all the parts produced are sequentially assembled and welded layer by layer to finally assemble and weld the large thin-walled frame product.

[0058] As one of the preferred examples of the present application, the classification and splitting result of step S13 includes "thin-walled pipes, special-shaped structural parts" or "thin-walled pipes, special-shaped structural parts, and plates".

[0059] Specifically, in general cases, the large thin-walled titanium alloy frame structure can at least include the first two of "thin-walled pipes, special-shaped structural parts, and plates". Further corresponding to step S2, the special-shaped structural parts can be casted into shape, but the thin-walled pipes can be machined into seamless pipes; and when the plates are also included, the plates can be rolled into shape.

[0060] Of course, the present application here is only a preferred example for general case illustration, and in some special structures, step S13 can also have other classification and splitting results, which are not particularly limited and illustrated here. In addition, corresponding to Example 1 below, it does not contain plates, but the thin-walled alloy pipe can be attributed to thin-walled pipes, and the pipe joint and the I-beam can be attributed to special-shaped structural parts.

[0061] Preferably, step S2 at least includes the first two or all of the following production processes:

[0062] S21: the special-shaped structural parts are produced by investment precision casting or machining graphite mold casting process;

[0063] S22: the thin-walled pipes are formed by seamless pipes or welded pipes;

[0064] S23: the plates are formed by hot rolling or cold rolling process.

[0065] Specifically, for any one of the production processes S21-S23, each of them includes two types of process production routes, wherein the route selection basis can correspond to the following respectively: the characteristics of the special-shaped structural parts, the characteristics requirements of the thin-walled pipes, and the characteristics and thickness of the plates. In addition, the production processes S21-S22 or S21-S23 have no sequence in the present application.

[0066] Preferably, step S3 includes the following specific manufacturing steps:

[0067] S31: A large welding platform is made to ensure that the welding platform is flat and meets the flatness requirements.

[0068] S32: A tooling for group welding is made.

[0069] Specifically, the material of the welding platform can be stainless steel, carbon steel, etc., and the flatness is generally ≤2mm; and the tooling can assist in controlling the group welding accuracy of each layer in step S4.

[0070] As one of the preferred examples of the present application, in step S32, the tooling at least includes: support tooling, fixed tooling, and anti-deformation tooling.

[0071] Preferably, step S4 includes the following steps of layer-by-layer group welding:

[0072] S41: Bottom layer group welding, find the reference and support and fix with tooling, position the corresponding part position, and then perform spot welding, size re-measurement, and full welding;

[0073] S42: Sequentially complete the individual group welding of all other layers;

[0074] S43: All layers are connected by corresponding support connectors for overall group welding from bottom to top.

[0075] Specifically, the present application is prepared by combining "casting, rolling, machining, and layer-by-layer group welding" to prepare large thin-walled titanium alloy frame structure, wherein in step S41, a gauge or laser positioning means can be used to position the corresponding part position; and step S42 at least includes upper layer group welding, and in step S42, the individual group welding of each layer can refer to and follow the bottom layer group welding in step S41.

[0076] Preferably, step S43 includes the following overall group welding steps:

[0077] S431: Adjust the spacing and angle between layers using support tooling;

[0078] S432: Determine the corresponding structure position using a laser positioning instrument;

[0079] S433: Weld from inside to outside until the product is fully welded;

[0080] S434: Ensure product size tolerance through detection and adjustment.

[0081] Specifically, in step S431, the bottom layer support tooling corresponding to the bottom layer group welding is used as the reference surface, and the support tooling of other layers is adjusted according to the difference; in step S433, point welding, symmetrical welding, intermittent welding, etc. can be used from inside to outside until the product is fully welded.

[0082] Example 1

[0083] A large thin-walled titanium alloy structural member is prepared from TC4.

[0084] I. Product Analysis

[0085] The size of the frame structural member is The minimum wall thickness is 3 mm. First, the shape and structure of the product are analyzed. The product has many small structures, a wall thickness of 3 mm, and a size cannot be directly cast into shape. The components can be divided into three categories: thin-walled alloy pipes, pipe joints, and I-beams. Second, different processes are used to produce each type of component. Thin-walled pipes are machined from seamless pipes, I-beams are cast from graphite molds, and pipe joints are cast from investment molds. Finally, the product can be divided into two layers according to its spatial structure, and each layer is welded separately. The final product is obtained by assembling the two layers. The design of the cast product is shown in Figures 1-2 .

[0086] II. Component Production

[0087] 1. The I-beam casting process uses graphite casting. The inner I-beam and outer circular I-beam are poured in sections in a VAC800KG vacuum casting furnace. The vacuum degree during pouring is ≤1 Pa, the melting current is ≥38 KA, the pouring and cooling time is 60 min, and after pouring, sandblasting and other processes are performed. After the workpiece is processed to be qualified, the anti-deformation ribs are removed, and the I-beam is ready for welding. The outer circular I-beam can be poured in sections with the aid of the sectional pouring mold shown in Figure 5 .

[0088] 2. The pipe joint casting uses investment precision casting. The pouring is carried out in a VAC150KG vacuum casting furnace. The vacuum degree during pouring is ≤1 Pa, the melting current is ≥22 KA, the pouring and cooling time is 30 min, and after pouring, sandblasting and other processes are performed to process the workpiece to be qualified.

[0089] 3. The thin-walled alloy pipe uses a seamless pipe. The production process route is: seamless pipe titanium ingot smelting - forging blank - forging rod machining centering hole - forging rod piercing - pipe expansion - straightening - non-destructive testing - machining - inspection.

[0090] III. Production Platform and Tooling

[0091] A special large welding platform is made of 30 mm thick 316L stainless steel plate. The welding platform needs to be flat and calibrated periodically with a level to ensure that the flatness of the welding platform is within 1 mm.

[0092] Supporting, fixing, and anti-deformation tooling is made of 316L stainless steel.

[0093] IV. Layer-by-Layer Assembly Welding

[0094] (1) Large outer circle I-beam group welding

[0095] With outer circle as reference, the segmented outer circle I-beam is fixed and compacted on the welding platform by using tooling, and after spot welding, detection and size accuracy adjustment are performed, and then full welding is performed. The outer circle I-beam finally welded has an outer diameter size accuracy of ±2mm.

[0096] (2) Bottom layer group welding

[0097] The outer circle I-beam is supported and fixed on the welding platform, laser positioning is used to determine the joint position for point-by-point welding, size re-measurement, and full welding forming.

[0098] (3) Upper layer group welding

[0099] The upper layer group welding method is the same as the bottom layer group welding.

[0100] (4) Overall group welding

[0101] Upper and lower layer butt joint: taking the bottom layer support tooling upper plane corresponding to the bottom layer group welding as reference surface, the height and angle of the upper layer support tooling are adjusted according to the difference, and then the upper layer group welding is supported and fixed. Then the laser positioning instrument is used to determine the positions of the 6 joints of the upper layer, 6 main supports are welded according to the positions, the key structure is spot welded from inside to outside, re-measured, and then full welding is performed by using symmetric welding and intermittent welding, and after the overall welding is completed, three-dimensional scanning detection is performed, the size tolerance of the key joints is ±2mm, which can meet the use requirements.

[0102] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for manufacturing a large thin-walled titanium alloy frame-like structural member, characterized by, It comprises the following steps: S1: product analysis and classification, comprising the following specific steps: S11: analyzing the shape structure of the product; S12: dividing the product into multiple layers and support connecting pieces between the layers according to the spatial structure of the product; S13: classifying and splitting all the parts in the product according to the different shape structures; the classification and splitting results include thin-walled pipes and special-shaped structural parts, and the special-shaped structural parts are pipe joints and I-beams; S2: part production, at least including the first two or all of the following production processes: S21: special-shaped structural parts are produced by using precision casting or machining graphite casting process; S22: thin-walled pipes are formed by using seamless pipes or welded pipes; S23: plates are formed by using hot rolling or cold rolling process; S3: making a platform and tooling; S4: layer-by-layer assembly welding, comprising the following layer-by-layer assembly welding steps: S40: large outer circle I-beam assembly welding, taking the outer circle as the reference, the segmented formed outer circle I-beam is fixed and compacted on the welding platform by using tooling, and then it is detected, adjusted in size accuracy, and then fully welded; S41: bottom layer assembly welding, finding the reference and supporting and fixing by using tooling, positioning the corresponding part position, and then performing spot welding, size re-measurement, and full welding; S42: sequentially completing the assembly welding of all other layers; S43: overall assembly welding of all layers from bottom to top through corresponding support connecting pieces, comprising the following overall assembly welding steps: S431: adjusting the spacing and angle between layers by using support tooling, taking the bottom layer support tooling plane corresponding to the bottom layer assembly welding as the reference surface, and adjusting the support tooling of other layers according to the difference; S432: determining the corresponding structure position by using a laser positioner; S433: welding from inside to outside until the product is fully welded; S434: ensuring the product size tolerance by detection and adjustment.

2. The method according to claim 1, wherein The classification and splitting results of step S13 include thin-walled pipes, special-shaped structural parts, and plates.

3. The method according to claim 1, wherein Step S3 comprises the following specific manufacturing steps: S31: manufacturing a special large welding platform to ensure that the welding platform is flat and meets the flatness requirements; S32: manufacturing tooling for assembly welding.

4. The method according to claim 3, wherein In step S32, the tooling at least includes support tooling, fixing tooling, and anti-deformation tooling.

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