Multi-process combined machining method for large-size titanium alloy frame structural component

Abstract

The invention provides a multi-process combined processing method for a large-size titanium alloy frame type structural member, which comprises the following steps: segmenting the large-size titanium alloy frame type structural member to obtain a plurality of process models and welding joint models on the process models; titanium alloy blank forging is conducted according to the process models and the welding joint models, semi-finish machining is conducted after blank forging is completed till the sizes of the process models are achieved, and the multiple process models are obtained; vacuum electron beam welding is conducted on the multiple process models, heat treatment is conducted after welding is completed, and after heat treatment is completed, surface allowance is removed through machining, and a part is obtained; and the quality of welding seams of the parts is detected through X-ray detection and ultrasonic flaw detection, and manufacturing of the large-size high-strength titanium alloy frame type structural parts is achieved.

Description

Technical Field

[0001] The invention relates to the field of aviation manufacturing, and in particular to a multi-process combined processing method for large-size titanium alloy frame-type structural parts. Background Art

[0002] Large-size frame components are an important part of the aircraft skeleton structure. They have complex structures, difficult processes, and high manufacturing risks. At the same time, due to the large number of them installed in the aircraft structure, they are an important factor restricting the progress of aircraft development. At the same time, with the development of material technology and manufacturing technology and the needs of aircraft performance and structure, the structural design of various advanced models at home and abroad has put forward higher and higher requirements for structural materials, namely high strength, light weight, and long life. TC4 titanium alloy has excellent comprehensive properties such as low quality and high strength, good corrosion resistance, and high temperature resistance. At the same time, TC4 titanium alloy can also be used in a variety of ways. Parts forming, welding and machining and other advantages, so it has been widely used in the field of aerospace.

[0003] At the same time, in recent years, the proportion of titanium alloy materials used in military and civilian aircraft is increasing, and the application level of titanium alloy materials has become one of the important indicators of aircraft advancement. Therefore, traditional small and medium-sized frame parts are mostly made of T-titanium alloy forgings through integral machining. However, 1. For large-sized rear body frame components of 2m in length, due to the limitation of the forging size of TC4 titanium alloy forging blanks, they cannot be forged and machined as a whole; 2. In order to strengthen the frame in large rear body frame components, 20mm thick high ribs will be extended on both sides of the frame. After adding the high ribs, the overall thickness of the rear body frame exceeds 300mm, but the current maximum thickness of the forging is 300mm, which also cannot be forged and machined as a whole.

[0004] In order to solve the problem that such large-sized high-strength titanium alloy frame-type structural parts cannot be integrally formed, it is urgently necessary to invent a multi-process combination processing method for large-sized high-strength titanium alloy frame-type structural parts. Summary of the invention

[0005] The invention provides a multi-process combined processing method for large-size titanium alloy frame-type structural parts.

[0006] The present invention provides a multi-process combined processing method for large-size titanium alloy frame-type structural parts, comprising:

[0007] The large-sized titanium alloy frame-type structural parts are segmented to obtain multiple process models and welding joint models on each process model;

[0008] Forging titanium alloy raw materials according to the process model and the welding joint model, and semi-finishing the raw materials to the size of the process model after the forging is completed, so as to obtain multiple process models;

[0009] Vacuum electron beam welding is performed on multiple process models, and heat treatment is performed after welding. After the heat treatment, mechanical processing is performed to remove the surface excess to obtain parts;

[0010] The quality of parts welds is checked through X-ray inspection and ultrasonic flaw detection to enable the manufacture of large-size and high-strength titanium alloy frame structural parts.

[0011] Optionally, before vacuum electron beam welding for multiple process models, including:

[0012] Determine the welding process flow and vacuum electron beam welding parameters.

[0013] Optionally, when the large-size titanium alloy frame-type structural member is a fixed frame at the engine position, the process model includes: a rear body frame upper body, a rear body frame lower body, a reinforcing ear piece, and an introduction and extraction block process model.

[0014] Optionally, the welding joint model includes: a medium thickness welding joint and a large thickness welding joint;

[0015] The weld joint model on the reinforcing lug is a medium thickness weld joint;

[0016] The model of the welding joint on the upper body of the rear body frame connected to the reinforcing ear piece is a medium-thickness welding joint; the model of the welding joint on the upper body of the rear body frame connected to the lower body of the rear body frame is a large-thickness welding joint;

[0017] The welding joint model on the lower body of the rear body frame is a large thickness welding joint;

[0018] The model of the welded joint connected to the reinforcing lug on the lead-in and lead-out blocks is a medium-thickness welded joint;

[0019] The welding joint model on the lead-in and lead-out block connected with the upper body of the rear body frame and the lower body of the rear body frame is a large thickness welding joint.

[0020] Optionally, the method further includes:

[0021] Carry out forging of bottom pads;

[0022] Before performing vacuum electron beam welding on a plurality of process models, the method further comprises:

[0023] The upper body of the rear body frame and the lower body of the rear body frame are spot-welded to the bottom pad, and the bottom pad is removed during the process of removing the surface excess by mechanical processing.

[0024] Optionally, the thickness of the medium-thickness welded joint is 20 mm, and the form of the medium-thickness welded joint is a bottom-locked butt joint;

[0025] The thickness of the large thickness welding joint is 130mm, and the large thickness joint form is butt joint;

[0026] The bottom pad is located in the middle of the bottom of the thick welding joint, and a groove is arranged above the bottom pad.

[0027] Optionally, spot welding is performed using argon arc welding.

[0028] Optionally, before performing vacuum electron beam welding on multiple process models, the method includes:

[0029] Spot-weld the lead-in and lead-out blocks to the reinforcing lugs;

[0030] Spot-weld the upper body of the rear body frame and the lower body of the rear body frame to the bottom pad;

[0031] The lead-in and lead-out blocks are spot-welded to the upper body of the rear body frame and the lower body of the rear body frame;

[0032] And in the process of removing the surface excess by mechanical processing, the bottom pad is removed and the lead-out blocks are introduced.

[0033] The invention provides a multi-process combined processing method for large-size titanium alloy frame-type structural parts, which can solve the manufacturing problem of large-size high-strength titanium alloy frame-type combined components with a thickness of 300 mm and a length of 2 m or more. At present, there is no effective process method to realize low-cost and rapid manufacturing of this type of components. The above processing method can effectively solve the manufacturing problem of this type of components and promote the development of large-scale rear body frame-type components; a multi-process combined processing method for large-size high-strength titanium alloy frame-type structural parts is designed, and the method can be promoted and applied to other large similar components; the quality of the component welding joint is high, and the strength of the joint after welding can reach more than 90% of the strength of the parent material, meeting the requirements of engineering use; the manufacturing technology and process adopted in the method are conventional and mature process methods, with low manufacturing cost and high manufacturing efficiency; the component manufacturing precision is high, firstly, a margin is reserved on the surface of the component, and welding and heat treatment are performed in a semi-finishing state, and after welding and heat treatment are completed, the margin is removed in the finishing process according to the deformation of the component, and the manufacturing precision of the component can be guaranteed by reserving the margin and removing the margin according to the deformation of the component during the finishing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a front view of a large-scale titanium alloy frame-type component model;

[0035] Figure 2 It is a schematic diagram of the reverse side of a large-sized titanium alloy frame-type component model;

[0036] Figure 3 It is a model for medium thickness bottom-lock butt joints;

[0037] Figure 4It is a model for butt joints with large thickness and gasket strips;

[0038] Figure 5 A flowchart for specific implementation;

[0039] Description of reference numerals:

[0040] 1 is the upper body model of the rear body frame, 2 is the lower body model of the rear body frame, 3 and 4 are the reinforcement ear models, 5 and 6 are the reinforcement ear models, 7, 8, 9, 10, 11 and 12 are the lead-in and lead-out block models, 13, 14, 15, 16, 17, 18, 19 and 20 are the lead-in and lead-out block models, and 21 is the bottom pad model. DETAILED DESCRIPTION

[0041] The present application is further described in detail below with reference to examples and drawings:

[0042] The present invention provides a multi-process combined processing method for large-size titanium alloy frame structural parts. The main idea is to design a segmented process model for the rear body frame component and design welding joints of different thicknesses. After the design is completed, the titanium alloy rough material is forged according to the process model. After the rough material forging is completed, the rough material is semi-finished to the process model size by using mechanical processing technology, and vacuum electron beam welding parameters and welding process flow are simultaneously formulated. After the mechanical processing is completed, vacuum electron beam welding is performed according to the designed welding parameters and welding process flow. After the welding is completed, heat treatment is performed. After the heat treatment is completed, mechanical processing is used to remove the surface excess of the parts. After the excess is removed, the weld quality is checked by X-ray detection and ultrasonic flaw detection, and finally the manufacturing of large-size high-strength titanium alloy frame structural parts is realized. The specific steps are as follows:

[0043] 1. Carry out segmented design of the process model of the rear body frame assembly, and respectively design the process models of the rear body frame upper body, rear body frame lower body, reinforcement ear piece, lead-in and lead-out block, and bottom pad;

[0044] 2. Construct the medium thickness (20mm) welding joint form, which is the bottom lock joint. According to the medium thickness welding joint form, construct the semi-finishing process digital model of the welded joint before welding, and determine the installation position of the lead-in and lead-out blocks;

[0045] 3. Construct a large thickness (130mm) welding joint form. The large thickness joint form is a butt joint. A gasket with a groove is set at the bottom of the joint. According to the large thickness welding joint form, a semi-finishing process digital model of the welded joint before welding is constructed, and the installation position of the lead-in and lead-out block, the installation position of the gasket and the direction of the gasket groove are determined;

[0046] 4. Forge the titanium alloy forging raw material according to the constructed process model, and after forging, perform semi-finishing before welding according to the process model;

[0047] 5. Formulate welding process parameters and welding process flow of medium and large thickness joints according to the process model of component welding joints, characteristics of component materials, welding equipment parameters, etc.;

[0048] 6. First, use argon arc welding to position the components, and then combine the established vacuum electron beam welding process parameters and process flow to perform preheating welding, formal welding, and finishing welding;

[0049] 7. Perform stress relief heat treatment on components after welding;

[0050] 8. Carry out fine processing on the components, remove the surface excess of the components, and introduce and remove the blocks and pads;

[0051] 9. Use X-ray to inspect the weld quality of medium-thickness lock-bottom butt joints, and use ultrasonic testing to inspect the weld quality of thick butt joints.

[0052] like Figure 1-4 As shown, in this embodiment, the rear frame component is 1.6m long, 1.5m wide, and 0.24m high. TC4-DT titanium alloy is used. The processes involved in the processing of the rear frame component include titanium alloy forging, process model design, mechanical processing, welding, heat treatment, and non-destructive testing. The specific implementation steps are as follows:

[0053] 1. The rear body frame assembly is divided into sections for process model design. After the section design is completed, there are 6 process models in total, among which model No. 1 is the upper body of the rear body frame, model No. 2 is the lower body of the rear body frame, and models No. 3, 4, 5, and 6 are reinforced ear pieces. The 6 process models are shown in the attached Figure 1 , Attachment Figure 2 ;

[0054] 2. Construct the process model of medium-thickness lock-bottom butt joint. The form of medium-thickness welding joint is 20mm lock-bottom butt joint. The size of the medium-thickness joint to be welded on model No. 1 is constructed to be 20mm. The size of the joint to be welded of models No. 3, 4, 5, and 6 is constructed to be 20mm respectively. The two ends of the joint to be welded are constructed as flat end faces. A 20mm×15mm lock-bottom step is constructed at the bottom of the joint to be welded. At the corners of the welding joints of models No. 3, 4, 5, and 6, lead-in and lead-out block models No. 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, and 18 are constructed respectively. The lead-in and lead-out blocks are made of the same material and thickness as the rear frame assembly, with a size of 40×40×20mm. The form of the medium-thickness lock-bottom butt joint is shown in the attached Figure 3 ;

[0055] 3. Construct a process model of a butt joint with a large thickness of gasket strips. The form of a large thickness welding joint is a 130mm bottom butt joint with a gasket strip. The dimensions of the parts to be welded in models No. 1 and No. 2 are respectively constructed as 1000mm×160mm×130mm. Next, construct the lead-in and lead-out block models at both ends of the large thickness welding joints No. 19 and No. 20. The dimensions of the models No. 19 and No. 20 are both 130mm×40mm×40mm. Finally, construct the bottom gasket strip model No. 21. The size of the gasket strip is 1080mm×40mm×40mm. The gasket strip is placed directly below the weld, and a 1080mm×5mm×5mm groove is constructed in the center of the gasket strip. The form of the butt joint with a large thickness of gasket strips is shown in the attached Figure 4 ;

[0056] 4. Complete the forging process of titanium alloy forging blanks according to the constructed process model;

[0057] 5. Perform mechanical semi-finishing on the forged blank according to the dimensions of the constructed process model;

[0058] 6. Combine the component welding joint process model, component material characteristics, and welding equipment parameters to formulate the electron beam welding parameters for medium and large thickness joints, simulate the welding joint form to conduct multiple rounds of welding process tests, and check the weld formation quality, weld cross-sectional morphology, and weld internal quality in turn, and finally determine the welding parameters for medium and large thickness joints;

[0059] 7. For the welding of medium-thickness bottom-locked butt joints, firstly, argon arc welding is used to position-weld the No. 4 and 6 reinforcing ear pieces on the No. 1 rear body frame upper body. After the positioning is completed, argon arc welding is used to position-weld the No. 10, 12, 16, and 18 lead-in blocks with the No. 4 and 6 reinforcing ear pieces and the No. 1 rear body frame upper body respectively. After the argon arc welding positioning welding is completed, the established vacuum electron beam welding parameters are used to perform electron beam positioning welding, preheating welding, and formal welding on the No. 1 rear body frame upper body and the No. 3 and 4 reinforcing ear pieces to be welded. After the electron beam welding is completed, mechanical processing technology is used to remove the No. 10, 12, 16, and 18 lead-in blocks. Similarly, the argon arc welding positioning welding, electron beam positioning welding, preheating welding, formal welding, and finally mechanical processing and removal of the lead-in blocks of other medium-thickness bottom-locked butt joints between the rear body frame upper body and the reinforcing ear pieces and the lead-in blocks are completed according to the above welding process.

[0060] 8. For the welding of the butt joint with large thickness and gasket strips, firstly, the No. 1 rear body frame upper body and the No. 2 rear body frame lower body are positioned and welded by argon arc welding, and then the No. 19 and No. 20 lead-in and lead-out blocks and the No. 21 bottom gasket strip are positioned and welded to the rear body frame body by argon arc welding. When the No. 21 bottom gasket strip is positioned and welded to the rear body frame body, the gasket strip is placed at the bottom of the rear body frame body with the groove facing upward. After the argon arc welding positioning welding is completed, the No. 1 rear body frame upper body and the No. 2 rear body frame lower body to be welded are respectively electron beam positioned, preheated and formally welded by using the established vacuum electron beam welding parameters;

[0061] 9. Perform stress relief heat treatment on the frame components after welding;

[0062] 10. Use mechanical processing technology to fine-process the heat-treated rear frame components, remove the surface excess of the components, lead-in blocks and back pads;

[0063] 11. Use X-ray to inspect the weld quality of medium-thickness lock-bottom butt joints, and use ultrasonic testing to inspect the weld quality of thick butt joints.

[0064] During electron beam welding, a spike structure will appear at the bottom of the weld. The performance of this structure is poor. The use of a lock-bottom butt medium-thickness joint and a thick joint with a pad can transfer the spike structure to the lock-bottom position and the pad. The tail of the spike can be removed by subsequent machining to improve the quality of the weld.

[0065] Based on the beam accessibility of the electron beam welder and the material forging capacity, the medium-thickness welding joints are segmented. When the joint segment is close to the upper body frame, the electron beam welding gun cannot reach it. When the joint segment is close to the reinforcing ear, the material forging thickness cannot be reached. The segmented surface distance of the medium-thickness welding joint is determined to be 10mm, which can meet the beam accessibility and the thickness of the forging.

[0066] Based on the material forging capacity and the optimal implementation path of electron beam welding, the large thickness welded joints are segmented. The segmented positions of the large thickness welded joints are close to the middle part of the component. The sizes of the upper and lower parts are close and meet the forging capacity of the forging. At the same time, the middle part is only a straight weld after segmentation, which is convenient for implementation during electron beam welding.

Claims

1. A multi-process combined processing method for large-size titanium alloy frame structural parts, characterized in that: include: The large-sized titanium alloy frame-type structural parts are segmented to obtain multiple process models and welding joint models on each process model; Forging titanium alloy raw materials according to the process model and the welding joint model, and semi-finishing the raw materials to the size of the process model after the forging is completed, so as to obtain multiple process models; Vacuum electron beam welding is performed on multiple process models, and heat treatment is performed after welding. After the heat treatment, mechanical processing is performed to remove the surface excess to obtain parts; The quality of parts welds is checked through X-ray inspection and ultrasonic flaw detection to enable the manufacture of large-size and high-strength titanium alloy frame structural parts.

2. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 1 is characterized in that: Prior to vacuum electron beam welding of multiple process models, including: Determine the welding process flow and vacuum electron beam welding parameters.

3. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 1 is characterized in that: When the large-size titanium alloy frame-type structural parts are fixed frames at the engine position, the process model includes: a rear body frame upper body, a rear body frame lower body, a reinforcing ear piece, and an introduction and extraction block process model.

4. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 3 is characterized in that: Welding joint models include: medium thickness welding joint and large thickness welding joint; The weld joint model on the reinforcing lug is a medium thickness weld joint; The model of the welding joint on the upper body of the rear body frame connected to the reinforcing ear piece is a medium-thickness welding joint; the model of the welding joint on the upper body of the rear body frame connected to the lower body of the rear body frame is a large-thickness welding joint; The welding joint model on the lower body of the rear body frame is a large thickness welding joint; The model of the welded joint connected to the reinforcing lug on the lead-in and lead-out blocks is a medium-thickness welded joint; The welding joint model on the lead-in and lead-out block connected with the upper body of the rear body frame and the lower body of the rear body frame is a large thickness welding joint.

5. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 4 is characterized in that: The method further comprises: Carry out forging of bottom pads; Before performing vacuum electron beam welding on a plurality of process models, the method further comprises: The upper body of the rear body frame and the lower body of the rear body frame are spot-welded to the bottom pad, and the bottom pad is removed during the process of removing the surface excess by mechanical processing.

6. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 5 is characterized in that: The thickness of the medium thickness welding joint is 20mm, and the form of the medium thickness welding joint is lock bottom butt joint; The thickness of the large thickness welding joint is 130mm, and the large thickness joint form is butt joint; The bottom pad is located in the middle of the bottom of the thickest welding joint, and a groove is arranged above the bottom pad.

7. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 5 is characterized in that: Spot welding uses argon arc welding.

8. The multi-process combined processing method for large-size titanium alloy frame-type structural parts according to claim 5 is characterized in that: Before performing vacuum electron beam welding on a plurality of process models, the method includes: Spot-weld the lead-in and lead-out blocks to the reinforcing lugs; Spot-weld the upper body of the rear body frame and the lower body of the rear body frame to the bottom pad; The lead-in and lead-out blocks are spot-welded to the upper body of the rear body frame and the lower body of the rear body frame; And in the process of removing the surface excess by mechanical processing, the bottom pad is removed and the lead-out blocks are introduced.

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