Narrow groove welding method for titanium alloy large complex space component

Abstract

The invention belongs to the technical field of welding, and discloses a titanium alloy large complex space component narrow groove welding method which comprises the following specific steps: step 1, workpiece treatment: machining the groove angle of a to-be-welded titanium alloy large complex component to be 40-50 degrees; secondly, first welding is conducted, wherein manual TIG welding is adopted for bottoming; thirdly, second welding is conducted, wherein MIG welding filling is adopted; fourthly, third-pass welding is conducted, specifically, the cover face is welded through MIG; and fifthly, supplementary welding is conducted, specifically, the welding seam forming condition of the MIG welding cover face is judged, and if stress concentration exists on the front face and the back face of cover face welding seam forming, manual TIG welding is adopted for modifying MIG cover face welding seam forming. According to the technical scheme, the welding quality is good, deformation is small, and the welding efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of welding, and in particular relates to a narrow groove welding method for a large and complex space component of a titanium alloy. Background Art

[0002] With the current combat requirements of rapid and full-domain mobile deployment of weapons and equipment, higher requirements are placed on lightweight materials. Titanium alloy is the preferred material for lightweighting and performance improvement of weapons and equipment due to its high specific strength, corrosion resistance, low density and other excellent properties. The shell of a certain armored assault equipment is made of titanium alloy. It is a complex box-type welded structure. The shell material involves a variety of thickness specifications such as 10mm-40mm. The joint form is mainly butt joints and corner joints. The groove angle is mainly 60°, and the welding position is variable (flat welding, horizontal welding, vertical welding, overhead angle welding, etc.). For details, see Figure 1 The manual TIG multi-layer and multi-pass welding with conventional drag hood and argon blowing protection measures is mainly adopted. The single-pass weld of manual TIG welding has a small penetration depth and width, resulting in many titanium alloy welding layers and passes, low welding efficiency, high overall welding heat input, and large welding deformation. In order to avoid oxidation, the control of interlayer temperature also reduces the welding efficiency of titanium alloy, which cannot meet the task of batch, efficient and high-quality production.

[0003] MIG welding is much more efficient than TIG welding, and has better accessibility than manual TIG welding. Compared with TIG welding, MIG welding can use a larger welding current and automatic wire feeding, has a greater welding penetration, higher deposition efficiency, and a single pass can replace multiple passes of TIG welding. The overall heat input is smaller, the welding deformation is smaller, and the welding strength is higher. The quality of MIG welding of titanium alloys is equivalent to that of traditional TIG welding, and the automatic wire feeding welding with large current is more efficient. However, the welding process is unstable and the spatter is large, which affects the argon blowing protection of the drag hood, thereby causing the titanium alloy to absorb oxygen, nitrogen, and hydrogen at high temperature and seriously affecting the performance of the weld joint. In addition, the front and back excess heights of the weld are large, which also causes stress concentration. Therefore, it is almost blank in the welding of large and complex space components of titanium alloys. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the starting depth and width of a single-pass weld in manual TIG welding is small, resulting in many titanium alloy welding layers and passes, low welding efficiency, and multi-layer and multi-pass welding resulting in high overall welding heat input and large welding deformation.

[0005] In order to solve the above technical problems, the specific technical solutions of the present invention are as follows:

[0006] A method for narrow groove welding of large complex space components of titanium alloy, the specific steps are as follows:

[0007] Step 1: Workpiece processing: Process the groove angle of the large and complex titanium alloy component to be welded to 40°-50°;

[0008] Step 2: First welding: manual TIG welding for base application;

[0009] Step 3: Second welding: MIG welding filling;

[0010] Step 4: The third welding: Use MIG welding to weld the cover surface;

[0011] Step 5: Supplementary welding: Determine the weld formation of the MIG welding cover. If there is stress concentration on the front and back of the cover weld, use manual TIG welding to modify the MIG cover weld formation.

[0012] Preferably, the groove angle of the large complex titanium alloy component to be welded is 46°.

[0013] Preferably, the bottom gap of the first welding is 2 mm.

[0014] Preferably, the ratio of MIG welding shielding gas is 50% Ar / 50% He.

[0015] Preferably, the wire diameter for all welds is 1.2 mm.

[0016] Preferably, the current for all welding is 150-170A.

[0017] Preferably, the voltage for all welding is 22-24V.

[0018] Preferably, the speed of all welding is 480 mm / min.

[0019] The present invention has the following advantages: 1. It optimizes the groove angle of large and complex titanium alloy components, reduces the amount of titanium alloy welding filling, improves welding efficiency, reduces welding heat input, improves weld performance, and improves weld quality; 2. Manual TIG welding is used for base welding of large and complex titanium alloy spatial components, which can well ensure that the base welding penetrates the root of the weld, the welding process is stable, and the back drag cover has a good protection effect, providing a protective basis for MIG welding filling and covering; 3. MIG welding is used for filling and covering of large and complex titanium alloy spatial components, the structure of manual TIG welding base weld is improved, the performance of titanium alloy welds is improved, and the welding efficiency is greatly improved; 4. The welding efficiency and welding quality of large and complex titanium alloy components are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Typical welding structure and joint form of the shell part;

[0021] Figure 2It is a schematic diagram of the narrow groove structure of the large complex space component of titanium alloy of the present invention;

[0022] Figure 3 It is a schematic diagram of the high-efficiency and high-quality interactive welding process for narrow grooves of large and complex spatial components made of titanium alloy according to the present invention. DETAILED DESCRIPTION

[0023] In order to better understand the purpose, structure and function of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings.

[0024] like Figure 2-Figure 3 As shown, this embodiment analyzes the typical structure and joint form of the shell, fully considers the characteristics of the manual TIG multi-layer and multi-pass welding and MIG welding methods of the conventional drag hood argon blowing protection measures, optimizes the welding groove angle, and changes it from the original 60° to 46°, reducing the filling amount and improving the welding efficiency. The performance of the 46° weld is basically the same as that of the 60° weld; combined with manual TIG welding primer, it provides a basis for MIG welding filling cover protection, and determines the joint interactive welding process method with complementary advantages of manual TIG welding and MIG welding. It is used for the welding and manufacturing of large and complex space components of titanium alloys. A narrow groove, efficient and high-quality interactive welding process method is provided for the welding and forming of large and complex space structures similar to titanium alloys. The specific steps are as follows:

[0025] Step 1: Change the groove angle of the large complex titanium alloy component to be welded from the original 60° to 40°-50° (see Figure 2 ), the amount of titanium alloy welding filler is reduced, the welding efficiency is improved, and the reduction of welding heat input also improves the performance of the weld and improves the weld quality;

[0026] Step 2: The first welding of large and complex titanium alloy space components is done by manual TIG welding, which can well ensure that the base welding penetrates the weld root, the welding process is stable, and the back drag shield has a good protection effect, providing a protective foundation for MIG welding filling cover;

[0027] Step 3: The second welding of large and complex titanium alloy space components adopts MIG welding filling, which improves the organization of manual TIG welding base weld, improves the performance of titanium alloy welds, and greatly improves welding efficiency;

[0028] Step 4: The third pass of MIG welding is used to cover the large and complex titanium alloy space components, which further improves the welding efficiency.

[0029] Step 5. According to the weld formation of MIG cap weld, if the front and back excess heights of the cap weld are large, causing stress concentration, manual TIG welding can be used to modify the MIG cap weld formation, reduce stress concentration, and improve weld quality.

[0030] Among them, MIG welding selects consumable pulse argon arc welding, which has a stable welding process, small spatter, good weld formation, a wide current adjustment range, and can effectively control the welding line energy, which is conducive to all-position welding and high weld quality. The best ratio of shielding gas is 50% Ar / 50% He, and the welding process parameters are shown in Table 1 below. At this time, the weld is beautiful, spatter is small, and the mechanical properties of the weld joint are slightly better than those of the TIG weld joint.

[0031] Table 1 Optimal process parameters for MIG welding of titanium alloy

[0032]

[0033] This patent fully analyzes the large and complex space structure of titanium alloy, takes into account the characteristics of the manual TIG welding and MIG welding methods, optimizes the welding groove angle, and adopts a 46° groove angle; combined with manual TIG welding, it provides a protective basis for MIG welding filling and capping, and determines the high-efficiency and high-quality interactive welding process method of narrow grooves of large and complex space components of titanium alloy with complementary advantages of manual TIG welding and MIG welding. The manual TIG welding is used for the base welding, which has mature welding technology, high weld strength, good plasticity and toughness, and stable welding process. It can well ensure that the base welding penetrates the weld root, and the drag cover has a good protection effect, avoiding the problem of base welding being oxidized. It is suitable for 46° narrow groove welding and can effectively reduce the filling amount; manual TIG base avoids the shortcomings of MIG welding that is not suitable for 46° narrow groove base welding and the problem of unstable back protection during MIG welding. MIG welding is used for filling and capping, which greatly reduces the problems of low welding efficiency, large welding deformation caused by large heat input and reduced performance caused by multi-layer and multi-pass manual TIG welding, and improves welding efficiency and welding quality. The narrow groove manual TIG welding-MIG welding of large and complex space components of titanium alloy has good welding quality, small deformation and high welding efficiency.

[0034] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, it is apparent to those skilled in the art that several modifications and improvements may be made without departing from the principles of the present invention, and these modifications and improvements should also be considered to fall within the scope of protection of the present invention.

Claims

1. A method for narrow groove welding of large complex space components of titanium alloy, characterized in that: The specific steps are as follows: Step 1: Workpiece processing: Process the groove angle of the large and complex titanium alloy component to be welded to 40°-50°; Step 2: First welding: manual TIG welding for base application; Step 3: Second welding: MIG welding filling; Step 4: The third welding: Use MIG welding to weld the cover surface; Step 5: Supplementary welding: Determine the weld formation of the MIG welding cover. If there is stress concentration on the front and back of the cover weld, use manual TIG welding to modify the MIG cover weld formation.

2. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: The groove angle of the large and complex titanium alloy component to be welded is 46°.

3. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: The base gap for the first weld is 2mm.

4. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: The ratio of MIG welding shielding gas is 50% Ar / 50% He.

5. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: The wire diameter for all welds was 1.2 mm.

6. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: All welding was done at 150-170A.

7. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: All welding voltage is 22-24V.

8. The narrow groove welding method of titanium alloy large complex space component according to claim 1 is characterized in that: The speed for all welding was 480 mm / min.

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