CN103831533A - Titanium alloy laser-MIG composite welding method - Google Patents

Abstract

The invention discloses a titanium alloy laser-MIG composite welding method. The titanium alloy joint to be welded is processed into an I-shaped groove, and the joint form is a butt joint; the welding seam protection drag cover is fixed on the MIG gun nozzle, and the main body of the drag cover is arranged on the surface of the weld seam; the laser beam is vertical from 0 to 3 mm in front of the MIG Incidence, the welding wire is sent to the upper surface of the groove through the MIG nozzle; the compound heat source melts the welding wire and fills the joint gap to realize the single-pass welding of the workpiece. The invention solves the shortcomings of titanium alloy welding seams that are easily polluted, high requirements for laser welding assembly conditions, low MIG welding efficiency, large heat-affected zone of weld seams, increased pores and cracks, etc.; without reducing welding efficiency, it can reduce Requirements for assembly conditions. It has the characteristics of large welding penetration, fast welding speed, small workpiece deformation, low assembly requirements, strong molten pool bridging ability, high welding quality, good weld performance, and easy to realize automatic welding.

Description

Titanium Alloy Laser-MIG Hybrid Welding Method

technical field

The invention relates to a titanium alloy composite welding method, in particular to a titanium alloy laser-MIG composite welding method, which belongs to the technical field of laser material processing.

Background technique

Titanium and titanium alloys have been widely used in the aerospace field because of their many unique excellent properties, such as high tensile strength, good high and low temperature performance, corrosion resistance, and high specific strength and specific stiffness. With the continuous expansion of the application range of titanium and titanium alloys, the welding problems have become increasingly prominent. As a precise, efficient and fast high-energy beam welding method, laser welding has been more and more widely used in the aerospace field. However, conventional laser welding also has some problems and defects, such as low utilization rate of laser energy and high assembly precision requirements. In order to solve these problems, laser-metal inert gas welding (hereinafter referred to as MIG) welding technology has received extensive attention. Laser-MIG hybrid welding is an organic combination of the advantages of laser welding and MIG welding. The laser energy utilization rate is improved, the stability of the welding process is improved, the quality of the weld seam is improved, and the requirements for the assembly accuracy of the welded parts are reduced. At the same time, it makes up for the shortcomings of MIG welding, such as slow welding speed, low efficiency, and large deformation.

During the laser-MIG hybrid welding process of titanium alloy, due to the high chemical activity of titanium alloy and the fast laser-MIG hybrid welding speed, the high-temperature area has a large area, and the welding high-temperature area is extremely susceptible to pollution from the surrounding environment. At present, there are few researches and applications on the technology research and application of optical laser-MIG composite welding titanium alloy.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention discloses a titanium alloy laser-MIG hybrid welding method, which aims to increase the welding penetration and improve the welding quality without increasing the laser power, and realize laser-MIG hybrid welding of titanium alloys. Get good welding performance.

The present invention adopts following technical scheme:

A titanium alloy laser-MIG hybrid welding method, the method comprising:

The first step: the titanium alloy joint to be welded is processed into an I-shaped groove, and the joint form is butt joint;

Step 2: Fix the welding seam protection towing cover on the MIG gun, and the main body of the towing cover is arranged on the surface of the welding seam;

Step 3: Arrange the composite heat source of laser and MIG, the laser beam is incident vertically from 0-3 mm in front of the MIG nozzle, and the welding wire is sent to the upper surface of the groove through the MIG nozzle;

Step 4: Use the laser beam and MIG composite heat source, the composite heat source melts the welding wire and fills the joint gap to realize the single-pass welding of the workpiece.

In the first step, the maximum gap of the I-type groove joint is not greater than 0.2 times the thickness of the joint. The maximum penetration depth of laser-MIG composite single-layer welding is predicted according to 2mm/kW.

During the welding process, the laser output power is 1.2～3.2Kw, the MIG output current is 35～65A; the welding speed is 600～1200mm/min; the wire feeding speed is 75～125ipm; the laser defocus is 0～2mm; the thickness of weldable titanium alloy is 2 ~6mm.

Use back protection gas, MIG gun gas and drag mask gas for protection, of which: back protection gas 2~5L/min, MIG gun gas 10~18L/min, drag mask gas 12~25L/min; use argon with a purity of 99.99% gas as a shielding gas.

The technical solution of the invention is to improve the welding penetration, organically combine the advantages of laser welding and MIG welding, and apply it to the welding of titanium alloys. The advantage of this invention is that it makes full use of the deep penetration characteristics of laser and the high filling efficiency of MIG welding. Under the interaction of laser and MIG, the stability of welding process is improved and the welding efficiency is improved. It solves the shortcomings of titanium alloy welding seams that are easily polluted, high requirements for laser welding assembly conditions, low MIG welding efficiency, large heat-affected zone of weld seams, and increased pores and cracks; without reducing welding efficiency, it reduces the impact on welding Assembly conditions required. It has the characteristics of large welding penetration, fast welding speed, small workpiece deformation, low assembly requirements, strong molten pool bridging ability, high welding quality, good weld performance, and easy to realize automatic welding.

Description of drawings

Figure 1 Schematic diagram of type I butt joint;

Fig. 2 Schematic diagram of laser-MIG hybrid welding of titanium alloy.

In the figure: δ is the joint thickness; 1-workpiece; 2-laser; 3-welding wire and shielding gas; 4-MIG welding torch;

Detailed ways

Below, the specific implementation manner of the invention will be further described in conjunction with the accompanying drawings and specific embodiments.

Working principle: The present invention is a titanium alloy laser-MIG composite welding method, through the organic combination of laser welding and MIG welding applied to the welding of titanium alloys, the design of different process parameters during welding achieves a specific purpose: to achieve a welding penetration Large, fast welding speed, small workpiece deformation, low assembly requirements, strong molten pool bridging ability, high welding quality, and good weld performance for titanium alloy welding.

In the welding method of the present invention, first, the joint of the titanium alloy to be welded is processed into an I-shaped groove. In order to control welding defects, there is a certain requirement for the assembly gap during welding, so the joint assembly must meet the gap not greater than 0.2δ (δ is the joint thickness) requirements. Select the welding wire according to the composition of the titanium alloy material to be welded, and perform pre-welding treatments such as degreasing, pickling, and drying on the weldment and the welding wire; fix the welding seam protection drag cover on the MIG gun nozzle, and the main body of the drag cover is arranged on the weld seam The above table: Arrange the composite heat source of laser and MIG. When welding, the laser beam is incident vertically from 0 to 3 mm in front of the MIG to ensure that the two heat sources together form a common molten pool. The welding wire is sent to the upper surface of the molten pool through the MIG nozzle to form a short-circuit transition; The composite heat source melts the welding wire and fills the joint gap to realize the single-pass welding of the workpiece. Using high-power laser beam combined with low-power MIG, laser power 1.2 ~ 3.2Kw, MIG current 35 ~ 60A, welding speed 600 ~ 1200mm/min, wire feeding speed 75 ~ 125ipm, laser defocus is 0 ~ 2mm; use Argon gas with a purity of 99.99% is used as the protective gas, and the back protective gas, MIG gun gas and drag hood gas are used for protection, of which: back protective gas 2～5L/min, MIG gun gas 10～18L/min, drag hood gas 12～ 25L/min.

According to the different thickness of the material, the specific welding parameters are selected with reference to Table 1.

Table 1 TA12 titanium alloy laser-MIG hybrid welding process specification

specific embodiment

The laser used is the HL4006D Nd:YAG solid-state laser produced by TRUMFP in Germany, with a rated power of 4kW and a continuous wave laser with an output wavelength of 1.06μm, and a focusing lens with a focal length of 200mm; Binzel APDMFⅡ wire feeder.

1) TA12 titanium alloy material 6mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 60A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 5L/min, the MIG gun gas is 18L/min, and the hood gas is 25L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no defects such as cracks, incomplete penetration and incomplete fusion inside, and no visible inclusions. The existing defects are mainly chain pores, and the pores are less than 0.5mm in diameter. The joint strength coefficient reaches 0.93.

2) TA12 titanium alloy material 3mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 50A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 3L/min, the MIG gun gas is 15L/min, and the hood gas is 20L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no internal defects such as cracks, incomplete penetration and incomplete fusion, and no visible inclusions. The joint strength coefficient reaches 0.96.

3) TA12 titanium alloy material 2mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 45A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 2L/min, the MIG gun gas is 12L/min, and the hood gas is 16L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no internal defects such as cracks, incomplete penetration and incomplete fusion, and no visible inclusions. The joint strength factor reaches 0.95.

4) TC1 titanium alloy material 6mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 60A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 5L/min, the MIG gun gas is 18L/min, and the hood gas is 25L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no defects such as cracks, incomplete penetration and incomplete fusion inside, and no visible inclusions. The existing defects are mainly chain pores, and the pores are less than 0.5mm in diameter. The joint strength coefficient reaches 0.93.

5) TC4 titanium alloy material 3mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 50A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 3L/min, the MIG gun gas is 15L/min, and the hood gas is 20L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no internal defects such as cracks, incomplete penetration and incomplete fusion, and no visible inclusions. The joint strength coefficient reaches 0.96.

6) TA15 titanium alloy material 2mm thick plate butt welding

The welding specifications are as follows: the groove type is type I; the welding wire is pure titanium welding wire with a diameter of 1.6mm; the distance between the light wires is 2mm, and the laser is in front; 45A, the shielding gas is 99.99% high-purity argon, the initial stage is YAG for 0.8s, MIG for 1s; the back shielding gas is 2L/min, the MIG gun gas is 12L/min, and the hood gas is 16L/min.

The titanium alloy flat plate butt weld obtained by the above-mentioned laser-MIG hybrid welding method has good shape, uniform corrugation, and good gas protection. There are no internal defects such as cracks, incomplete penetration and incomplete fusion, and no visible inclusions. The joint strength factor reaches 0.95.

The above descriptions are only preferred feasible embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Therefore, all equivalent structural changes made by using the description and accompanying drawings of the present invention are included in the protection scope of the present invention.

Claims (5)

1. a titanium alloy Laser-MIG Composite Welding method, comprising:

The first step: titanium alloy joint to be welded is processed into I type groove, joint form is docking;

Second step: drag cover to be fixed on MIG rifle weld seam protection, drag cover main body to arrange table in welded joints;

The 3rd step: arrange laser and MIG composite heat power supply, laser beam is from MIG rifle mouth front 0～3mm vertical incidence, and welding wire is sent into groove upper surface by MIG rifle mouth;

The 4th step: use laser beam and MIG composite heat power supply, fill play movement after composite heat power supply filler wire, realize workpiece single track welding fabrication.

2. titanium alloy Laser-MIG Composite Welding method according to claim 1, is characterized in that, in the first step, the maximal clearance of I type groove joint is not more than 0.2 times of joint thickness.

3. titanium alloy Laser-MIG Composite Welding method according to claim 1, is characterized in that, the maximum fusion penetration of laser-MIG composite single layer weldering carries out anticipation by 2mm/kW.

4. titanium alloy Laser-MIG Composite Welding method according to claim 1, is characterized in that, in welding process, and laser output power 1.2～3.2Kw, MIG output current 35～65A; Speed of welding 600～1200mm/min; Wire feed rate 75～125ipm; Laser defocusing amount is 0～2mm.

5. titanium alloy Laser-MIG Composite Welding method according to claim 1, is characterized in that, adopts back of the body protection gas, MIG rifle gas and drags cover gas mating protection, wherein: back of the body protection gas 2～5L/min, MIG rifle gas 10～18L/min, drag cover gas 12～25L/min.

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