CN106346126A - Method for electron beam welding of titanium alloy and red copper dissimilar metal - Google Patents

Abstract

The present invention is an electron beam welding method for dissimilar metals of titanium and copper, specifically an electron beam welding method for TC4 titanium alloy and T2 red copper. The specific steps of the method are as follows: first, preparatory work before welding is carried out; the first partial copper welding is completed ; Then use small beam current fast back-to-center welding to strengthen the root formation; finally, on the basis of the previous two weldings, use electron beam partial titanium alloy welding on one side. The welding method of the invention can effectively control the distribution and content of the primary unfavorable orientation intermetallic compound, and improve the strength and reliability of the welded joint.

Description

A kind of electron beam welding method of dissimilar metals of titanium alloy and red copper

technical field

The invention relates to the field of dissimilar metal welding, in particular to a welding method of TC4 titanium alloy and T2 red copper.

Background technique

Composite structures of dissimilar metals are widely used in aerospace, shipbuilding, power industry and other fields. Titanium alloys are widely used in aerospace, petrochemical and other fields because of their strong heat resistance, high specific strength, good plasticity, toughness and corrosion resistance. Copper alloys have excellent electrical conductivity, thermal conductivity, and excellent corrosion resistance. Some copper alloys also have high strength and are used in many parts in the aerospace field.

The welding of titanium-copper dissimilar metals can not only combine the material properties of each other to realize the multifunctionality of materials, but also explore high-strength titanium-copper joints as a transitional structure to solve the welding problems of other dissimilar metals such as titanium steel. Traditional titanium-copper welding, including brazing, fusion brazing, etc., due to the large difference in physical properties between the two materials and the formation of unfavorable brittle intermetallic compounds, the joint strength can only reach about 70% of the copper strength, which is difficult to achieve in actual engineering. application.

The composite structure of titanium-copper dissimilar metals not only meets the requirements of heat conduction, electrical conduction, wear resistance and corrosion resistance, but also can withstand a certain strength while reducing weight, but traditional fusion welding at high temperatures is easy to produce at the joints A large number of titanium-copper brittle intermetallic compounds seriously reduce the mechanical properties of the joint. The key to titanium-copper dissimilar metal welding is to effectively control the formation and growth of intermetallic compounds. Solid-phase welding methods such as explosive welding and friction welding can form titanium-copper joints, but they are limited in shape and size. Zhao Haisheng. Research on electron beam welding process of QCr0.8/TC4 dissimilar materials[D]. Harbin Institute of Technology, 2007. In this paper, electron beam centered welding of QCr0.8/TC4 dissimilar materials was studied, but the interface reaction layer is thick and the types of compounds And the number is large, the structure of the CuTi-based solid solution zone is coarse, the weld strength is low, and the connectivity is poor. Liu Wei, Chen Guoqing, Zhang Binggang, et al. Optimization of Electron Beam Welding Process for Copper/Titanium Alloy [J]. Journal of Welding Society, 2008, 29(5). The copper welding method improves the joint strength on the original basis, but the effect is not very obvious. There are still a large number of brittle intermetallic compounds in the weld and the distribution is irregular. The incomplete penetration of the root is also one of the reasons for the insignificant increase in the joint strength. . How to overcome the above-mentioned welding technical problems in the process has become a technical problem in the welding of TC4 titanium alloy and T2 copper.

Contents of the invention

The purpose of the present invention is to provide an electron beam welding method for titanium-copper dissimilar metals, which greatly optimizes the weak bonding surface of the joint by realizing the controlled growth of brittle intermetallic compounds, so as to solve the problem of low bonding strength of titanium-copper dissimilar metals.

Realize the object of the present invention and adopt following technical scheme:

A kind of electron beam welding method of TC4 titanium alloy and T2 red copper, concrete steps are as follows:

Step 1, prepare the TC4 titanium alloy plate and the T2 copper plate before welding;

Step 2, extract the vacuum and set the welding parameters: electron beam acceleration voltage, focusing current, welding height and filament current;

Step 3, set the electron beam current: 40mA-50mA, welding speed: 10mm/s, beam current rising and falling time: 1.5s; make the electron beam bias on the T2 copper plate side, the bias range: 1mm-3mm, Carry out welding, lower the beam and after the complete molten pool is formed, start the horizontal axis movement, and complete the vacuum welding on the front side of the T2 copper plate;

Step 4, set the electron beam current: 10mA-20mA, welding speed: 15-20mm/s, beam rising and falling time: 1.5s; carry out back center welding of TC4 titanium alloy plate and T2 copper plate, lower the beam and wait After the complete molten pool is formed, start the horizontal axis movement to complete the vacuum welding; electron beam welding has obvious deep perforation effect, the aspect ratio is large, and the root position of the welded joint may have poor fusion due to electron beam bias welding. Welding quality, the back of the electron beam uses a small beam to quickly center the weld for root forming strengthening.

Step 5, set the electron beam current: 20mA-30mA, welding speed: 10mm/s, beam current rise and fall time: 1.5s, bias the electron beam to the titanium side, the bias amount is 1.5-3.5mm, and perform TC4 Titanium alloy side welding, lower the beam and after the complete molten pool is formed, start the horizontal axis movement to complete the vacuum welding. By remodeling the weak interface of the offset welded titanium-copper joint, the reverse brittle intermetallic compound growth is realized, thereby achieving high-strength bonding of the joint.

Further, in step 1, the specific steps of preparation before welding are:

Step 1.1, use 280#, 400#, 600# mesh sandpaper to remove the titanium copper surface to be welded and the surface oxide layer of the surrounding 300mm area, and use acetone to clean the surface oil;

In step 1.2, the TC4 titanium alloy plate and the T2 copper plate are placed on the workbench and tightly connected without gaps.

Further, in step 2, the gun vacuum and chamber vacuum are respectively up to 8E ^-3 and 7E ^-2 .

Further, in step 2, the welding parameters are set as follows: electron beam accelerating voltage: 60KV, focusing current 600mA-650mA, welding height 260mm-290mm, filament current 400mA-450mA.

Further, the mass percentage of TC4 titanium alloy is composed of: Ti: 89.12%, Al: 6.42%, V: 4.30%, Fe: 0.05%, C: 0.03%; the mass percentage of T2 copper is composed of: Cu: ≥ 99.9%, O : 0.06%.

Compared with the prior art, the present invention has significant advantages as follows:

1. The present invention adopts a welding method in which the first beam current is biased on the copper side during the welding process of titanium-copper dissimilar metals. This method effectively controls the distribution and content of the primary unfavorable orientation intermetallic compounds and improves the strength of the welded joint and reliability.

2. On the back butt joint surface of the welding test plate, a small beam of rapid centering welding is carried out, which improves the bonding strength of the joint root, thereby further improving the connection reliability of the welded joint.

3. On the titanium side adjacent to the copper-biased welding seam, a titanium-biased welding was performed. On the basis of not destroying the original copper-biased welding connection interface, the titanium-biased welding changed the unfavorable orientation of the primary intermetallic compound through welding heat cycle growth direction, composition and content. The bonding strength of welded joints is greatly improved. The tensile strength reaches more than 90% of the copper base material, which is 220Mpa-250Mpa.

Description of drawings

Fig. 1 is the welding structure schematic diagram of the present invention;

Fig. 2 is a cross-sectional schematic diagram of a weld of the present invention;

Fig. 3 is the SEM microstructure diagram of weld seam in embodiment 1;

FIG. 4 is a SEM microstructure diagram of the weld in Example 2.

detailed description

The technical method of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.

The ZD60-6A 5001 vacuum electron beam welding machine developed by Beijing Aeronautical Manufacturing Engineering Research Institute is used to carry out electron beam welding of TC4 titanium alloy and T2 red copper. After assembly, the welding process is carried out as shown in Figure 1. as shown in picture 2.

Example 1

In the present embodiment, the electron beam adjacent welding method of titanium alloy TC4 and T2 red copper is carried out according to the following steps:

Use 280#, 400#, 600# mesh sandpaper to remove the oxide layer on the titanium copper surface to be welded and the surrounding 300mm area, and use acetone to clean the surface oil. Titanium-copper materials are TC4 and T2 red copper respectively, among which, the mass percentage of TC4 titanium alloy is composed of: Ti: 89.12%, Al: 6.42%, V: 4.30%, Fe: 0.05%, C: 0.03%; T2 red copper mass percentage group It becomes: Cu: ≥ 99.9%, O: 0.06%. Assemble the welded test panels, butt them tightly without opening grooves and without gaps. Fix the docking test plate at the focal point or the lower focal point of the electron beam spot surface in the vacuum chamber, and the docking surface is parallel to the moving direction of the horizontal guide rail.

Extract the vacuum, and when the gun vacuum and chamber vacuum reach the welding conditions, the gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , load high pressure, and set the welding parameters. Among them, electron beam accelerating voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 45mA, welding speed: 10mm/s, beam rising and falling time: 1.5s; start the vacuum chamber motion system servo Enable, move the vertical direction of the docking surface, so that the electron beam is biased on the copper side, the bias range: 1.5mm. After the parameter setting is completed, the welding is carried out. After the beam is lowered and the complete molten pool is formed, the horizontal axis movement is started to complete the first welding.

Turn off the vacuum in the chamber, remove the connecting test plate from the fixing fixture, replace the back as the welding surface, fix it again, keep the original welding height unchanged and make the butt surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

Extract the vacuum to the vacuum degree required by welding and below, the gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , and reset the electron beam parameters as follows: electron beam acceleration voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 15mA, welding speed: 15mm/s, beam current rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the second back welding.

Turn off the vacuum again, remove the connection test plate from the fixing fixture, and fix the original first welding surface as the front side again, while keeping the original welding height unchanged and making the butt joint surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

The electron beam is biased on the titanium side, the bias is 2mm, the vacuum is drawn, the gun vacuum and chamber vacuum are respectively 8E ^-3 and 7E ^-2 , and the electron beam parameters are reset as follows: electron beam acceleration voltage: 60KV, focusing Current 650mA, welding height 280mm, filament current 430mA; electron beam current: 20mA, welding speed: 10mm/s, beam rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the third adjacent welding.

FIG. 3 is a SEM microstructure diagram of a part of the weld seam in Example 1 of the present invention. As shown in the figure, the interfacial intermetallic transition layer is well formed and there is no thicker continuous intermetallic compound.

The joint strength of titanium alloy TC4 plate and T2 copper plate reaches 245Mpa.

Example 2

In the present embodiment, the electron beam welding method to titanium alloy TC4 and T2 red copper is carried out in the following steps:

Use 280#, 400#, 600# mesh sandpaper to remove the oxide layer on the titanium copper surface to be welded and the surrounding 300mm area, and use acetone to clean the surface oil. Titanium-copper materials are TC4 and T2 red copper respectively, among which, the mass percentage of TC4 titanium alloy is composed of: Ti: 89.12%, Al: 6.42%, V: 4.30%, Fe: 0.05%, C: 0.03%; T2 red copper mass percentage group It becomes: Cu: ≥ 99.9%, O: 0.06%. Assemble the welded test plates, butt them tightly without opening grooves and gaps. Fix the docking test plate at the focal point or the lower focal point of the electron beam spot surface in the vacuum chamber, and the docking surface is parallel to the moving direction of the horizontal guide rail.

Extract the vacuum, and when the gun vacuum and chamber vacuum reach the welding conditions, the gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , load high pressure, and set the welding parameters. Among them, electron beam accelerating voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 45mA, welding speed: 10mm/s, beam rising and falling time: 1.5s; start the vacuum chamber motion system servo Enable, move the vertical direction of the docking surface, so that the electron beam is biased on the copper side, the bias range: 1.5mm. After the parameter setting is completed, the welding is carried out. After the beam is lowered and the complete molten pool is formed, the horizontal axis movement is started to complete the first welding.

Turn off the vacuum in the chamber, remove the connecting test plate from the fixing fixture, replace the back as the welding surface, fix it again, keep the original welding height unchanged and make the butt surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

Extract the vacuum to the required vacuum degree for welding, gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , reset the electron beam parameters as follows: electron beam acceleration voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA ; Electron beam current: 15mA, welding speed: 15mm/s, beam current rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the second back welding.

As shown in FIG. 4 , it is a SEM microstructure diagram of a part of the weld seam in Example 2 of the present invention. As shown in the figure, the interface intermetallic compound transition layer is thick and the distribution is disordered.

The joint strength of titanium alloy TC4 plate and T2 copper plate welded by electron beam only on the copper side reaches 162Mpa.

Example 3

The electron beam adjacent welding method for titanium alloy TC4 and T2 red copper is carried out in the following steps:

Use 280#, 400#, 600# mesh sandpaper to remove the oxide layer on the titanium copper surface to be welded and the surrounding 300mm area, and use acetone to clean the surface oil. Titanium-copper materials are TC4 and T2 red copper respectively, among which, the mass percentage of TC4 titanium alloy is composed of: Ti: 89.12%, Al: 6.42%, V: 4.30%, Fe: 0.05%, C: 0.03%; T2 red copper mass percentage group It becomes: Cu: ≥ 99.9%, O: 0.06%. Assemble the welded test plates, butt them tightly without opening grooves and gaps. Fix the docking test plate at the focal point or the lower focal point of the electron beam spot surface in the vacuum chamber, and the docking surface is parallel to the moving direction of the horizontal guide rail.

Extract the vacuum, and when the gun vacuum and chamber vacuum reach the welding conditions, the gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , load high pressure, and set the welding parameters. Among them, electron beam accelerating voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 45mA, welding speed: 10mm/s, beam rising and falling time: 1.5s; start the vacuum chamber motion system servo Enable, move the vertical direction of the docking surface, so that the electron beam is biased on the copper side, the bias range: 1.5mm. After the parameter setting is completed, the welding is carried out. After the beam is lowered and the complete molten pool is formed, the horizontal axis movement is started to complete the first welding.

Turn off the vacuum in the chamber, remove the connecting test plate from the fixing fixture, replace the back as the welding surface, fix it again, keep the original welding height unchanged and make the butt surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

Extract the vacuum to the required vacuum degree for welding, gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , reset the electron beam parameters as follows: electron beam acceleration voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 15mA, welding speed: 15mm/s, beam current rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the second back welding.

Turn off the vacuum again, remove the connection test plate from the fixing fixture, and fix the original first welding surface as the front side again, while keeping the original welding height unchanged and making the butt joint surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

The electron beam is biased on the titanium side, the bias is 2.5mm, the vacuum is drawn, the gun vacuum and chamber vacuum are respectively 8E ^-3 and 7E ^-2 , and the electron beam parameters are reset as follows: electron beam acceleration voltage: 60KV, Focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 20mA, welding speed: 10mm/s, beam rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the third adjacent welding.

The joint strength of titanium alloy TC4 plate and T2 copper plate reaches 228Mpa.

Example 4

The electron beam adjacent welding method to titanium alloy TC4 and T2 red copper is carried out in the following steps in the present embodiment:

Use 280#, 400#, 600# mesh sandpaper to remove the oxide layer on the titanium copper surface to be welded and the surrounding 300mm area, and use acetone to clean the surface oil. Titanium-copper materials are TC4 and T2 red copper respectively, among which, the mass percentage of TC4 titanium alloy is composed of: Ti: 89.12%, Al: 6.42%, V: 4.30%, Fe: 0.05%, C: 0.03%; T2 red copper mass percentage group It becomes: Cu: ≥ 99.9%, O: 0.06%. Assemble the welded test plates, butt them tightly without opening grooves and gaps. Fix the docking test plate at the focal point or the lower focal point of the electron beam spot surface in the vacuum chamber, and the docking surface is parallel to the moving direction of the horizontal guide rail.

Extract the vacuum, and when the gun vacuum and chamber vacuum reach the welding conditions, the gun vacuum and chamber vacuum respectively reach below 8E ^-3 and 7E ^-2 , load high pressure, and set the welding parameters. Among them, electron beam accelerating voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 45mA, welding speed: 10mm/s, beam rising and falling time: 1.5s; start the vacuum chamber motion system servo Enable, move the vertical direction of the docking surface, so that the electron beam is biased on the copper side, the bias range: 1.5mm. After the parameter setting is completed, the welding is carried out. After the beam is lowered and the complete molten pool is formed, the horizontal axis movement is started to complete the first welding.

Turn off the vacuum in the chamber, remove the connecting test plate from the fixing fixture, replace the back as the welding surface, fix it again, keep the original welding height unchanged and make the butt surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

Extract the vacuum to the vacuum degree required by welding and below, the gun vacuum and chamber vacuum respectively reach 8E ^-3 and 7E ^-2 , and reset the electron beam parameters as follows: electron beam acceleration voltage: 60KV, focusing current 650mA, welding height 280mm, filament current 430mA; electron beam current: 15mA, welding speed: 15mm/s, beam current rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the second back welding.

Turn off the vacuum again, remove the connection test plate from the fixing fixture, and fix the original first welding surface as the front side again, while keeping the original welding height unchanged and making the butt joint surface parallel to the horizontal moving guide rail. Clean the soldered surfaces with acetone.

Make the electron beam bias on the titanium side, the bias amount is 3mm, pump the vacuum, the gun vacuum and chamber vacuum respectively reach 8E ^-3 , 7E ^-2 , reset the electron beam parameters as follows: electron beam acceleration voltage: 60KV, focusing Current 650mA, welding height 280mm, filament current 430mA; electron beam current: 20mA, welding speed: 10mm/s, beam rising and falling time: 1.5s. After the parameter setting is completed, welding is carried out. After the beam is lowered and a complete molten pool is formed, the horizontal axis movement is started to complete the third adjacent welding.

The joint strength of titanium alloy TC4 plate and T2 copper plate reaches 220Mpa.

Claims (5)

1. a kind of tc4 titanium alloy and the electro-beam welding method of t2 red copper are it is characterised in that specifically comprise the following steps that

Step 1, tc4 titanium alloy sheet and t2 copper plate are carried out welding front preparation；

Step 2, extracting vacuum, set welding parameter: beam voltage, focus current, welding and assembling height and heater current；

Step 3, sets electronic beam current: 40ma-50ma, speed of welding: 10mm/s, and line rises, fall time: 1.5s；Make electricity Beamlet is offset to t2 copper plate side, amount of bias scope: 1mm-3mm, is welded, lower restraint and after complete molten bath is formed, start Trunnion axis moves, and completes t2 copper plate side front and carries out vacuum welding；

Step 4, sets electronic beam current: 10ma-20ma, speed of welding: 15-20mm/s, and line rises, fall time: 1.5s；Enter Row tc4 titanium alloy sheet and t2 copper plate back centering weldering, lower restraint and after complete molten bath is formed, start trunnion axis motion complete true Missing solder connects；

Step 5, sets electronic beam current: 20ma-30ma, speed of welding: 10mm/s, and line rises, fall time: 1.5s, by electricity Beamlet is offset to titanium side, amount of bias be 1.5-3.5mm, carry out tc4 titanium alloy side welding, lower restraint and after complete molten bath is formed, Start trunnion axis motion and complete vacuum welding.

2. the electro-beam welding method of tc4 titanium alloy according to claim 1 and t2 red copper is it is characterised in that step 1 In, before described weldering, preparation process is:

Step 1.1, removes titanium copper surface to be welded and the oxidation of periphery 300mm region surface using 280#, 400#, 600# mesh number sand paper Layer, and carry out surface and oil contaminant cleaning using acetone；

Step 1.2, makes tc4 titanium alloy sheet and t2 copper plate place simultaneously gapless closed butt joint on the table.

3. the electro-beam welding method of tc4 titanium alloy according to claim 1 and t2 red copper is it is characterised in that step 2 In, described rifle vacuum, room vacuum respectively reach 8e^-3、7e^-2.

4. the electro-beam welding method of tc4 titanium alloy according to claim 1 and t2 red copper is it is characterised in that step 2 In, the welding parameter that sets is as beam voltage: 60kv, focus current 600ma-650ma, welding and assembling height 260mm- 290mm, heater current 400ma-450ma.

5. the electro-beam welding method of tc4 titanium alloy according to claim 1 and t2 red copper is it is characterised in that described Tc4 titanium alloy percent mass consists of: ti:89.12%, al:6.42%, v:4.30%, fe:0.05%, c:0.03%；T2 is purple Copper mass percentage composition is: cu: >=99.9%, o:0.06%.