A copper-nickel alloy and stainless steel laser welding device and process

Abstract

The present invention provides a copper-nickel alloy and stainless steel laser welding device and process, a laser emitting device, a gas protection device and a control device; the laser emitting device includes a laser welding gun and an optical fiber, the laser welding gun is used to emit laser to weld the workpiece; the gas protection device includes an air blowing protection chamber, the air blowing protection chamber is used to spray a first protective gas toward one side of the stainless steel workpiece and a second protective gas toward the copper-nickel alloy workpiece; the control device is used to control the operating parameters and activity trajectory of the laser emitting device and the gas protection device. The copper-nickel alloy and stainless steel laser welding device and process described in the present application can reduce the temperature difference between the two sides of the molten pool during welding, reduce the process-related pores generated during welding, reduce the porosity, and achieve precise distribution of laser welding energy on the stainless steel workpiece side and the copper-nickel alloy workpiece side, avoid thermal cracks due to imbalance in fusion ratio, and achieve good forming of the weld.

Description

Technical Field

[0001] The present invention relates to the technical field of laser welding, and in particular to a copper-nickel alloy and stainless steel laser welding device and process. Background Art

[0002] Copper-nickel alloys are primarily composed of copper and nickel, both of which have a face-centered cubic crystal structure. The two elements have similar electronegativity and atomic radius, allowing them to form an infinite solid solution, a single α-phase. Because the various phases of copper and nickel have similar basic properties and are infinitely soluble in each other at any composition, copper-nickel alloys do not undergo phase transformations during thermal deformation, thereby reducing the impact of the forming and welding processes on the corrosion resistance and mechanical properties of the copper-nickel alloy.

[0003] When the mass fraction of Ni is between 10% and 30%, it is commonly referred to as "white copper." At this point, the alloy has a wide passivation range and the best corrosion resistance. It also possesses exceptional resistance to seawater erosion, earning it the nickname "marine engineering alloy." When the mass fraction of Ni reaches 60%, it becomes monel alloy, which exhibits excellent corrosion resistance to hydrofluoric acid, hydrochloric acid, sulfuric acid, and their derivatives, allowing for more demanding applications. Stainless steel is also commonly used in applications with moderate corrosion requirements. Therefore, copper-nickel alloys and stainless steel are widely used in industries such as shipbuilding and marine engineering, petrochemicals, electric power, and pharmaceuticals and food.

[0004] With the continuous advancement of industrial technology, the demand for welding copper-nickel alloys and stainless steel dissimilar metals is increasing, and the welding thickness is also increasing. The traditional process uses a welding method that adds a Ni transition layer on the stainless steel side. Its welding quality stability, welding efficiency, and welding cost can no longer meet the development needs. Therefore, it is urgent to develop new welding technologies to achieve efficient and high-quality welding of copper-nickel alloys and stainless steel dissimilar metals.

[0005] In recent years, laser welding technology has developed rapidly. The energy density of laser welding can reach 1012J / m3. It not only has high energy density, but also can achieve precise control of heat input and is easy to automate, which is expected to solve the above-mentioned technical bottlenecks. As the plate thickness increases, the difficulty of laser welding increases due to the large physical differences between copper-nickel alloys and stainless steel dissimilar metals. Not only is the welding forming difficult to control, but the loss of control of the fusion ratio during the welding process will also cause a series of quality problems. Taking B10 and 316 stainless steel welding as an example, lower heat input will lead to poor forming, and higher heat input will lead to serious B10 side undercuts, burn-through and other defects. A larger fusion ratio will also lead to the production of uncontrollable metal compounds, forming penetration cracks and liquefaction cracks. At the same time, the pores in the welding process, especially the "process pores", cannot be effectively controlled. The above problems have seriously restricted the application of laser welding technology in copper-nickel alloys and stainless steel dissimilar metals, and hindered the development of the industry. Summary of the Invention

[0006] In view of this, the present invention aims to propose a copper-nickel alloy and stainless steel laser welding device and process to solve the problems in the prior art of copper-nickel alloy and stainless steel in which the weld cannot be well formed and defects such as cracks or pores appear during laser welding.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] A copper-nickel alloy and stainless steel laser welding device, comprising

[0009] Laser emission device, gas protection device and control device;

[0010] The laser emitting device includes a laser welding gun and an optical fiber, wherein the optical fiber is used to provide energy to the laser welding gun, and the laser welding gun is used to emit laser to weld the workpiece;

[0011] The gas protection device includes an air blowing protection chamber, which includes a first air blowing protection chamber and a second air blowing protection chamber. The first air blowing protection chamber is used to spray a first protective gas toward one side of the stainless steel workpiece, and the second air blowing protection chamber is used to spray a second protective gas toward one side of the copper-nickel alloy workpiece.

[0012] The control device is used to control the operating parameters and movement trajectory of the laser emitting device and the gas protection device.

[0013] The copper-nickel alloy and stainless steel laser welding device described in this application can effectively reduce the temperature difference on both sides of the molten pool during the welding process, reduce the process pores generated during the welding process, reduce the porosity, and achieve precise distribution of laser welding energy on the stainless steel workpiece side and the copper-nickel alloy workpiece side, avoiding thermal cracks due to imbalance in the fusion ratio, and achieving good weld formation.

[0014] Furthermore, a first conduit is provided at the upper end of the first air blowing protection chamber, and a first outlet is provided at the front end. The first conduit is connected to an external air supply device through a pipeline, and the first outlet is used to spray a first protective gas toward one side of the stainless steel workpiece. A second conduit is provided at the upper end of the second air blowing protection chamber, and a second outlet is provided at the front end. The second conduit is connected to an external air supply device through a pipeline, and the second outlet is used to spray a second protective gas toward one side of the copper-nickel alloy workpiece.

[0015] This structure can simultaneously spray different types of shielding gases onto the stainless steel workpiece and the copper-nickel alloy workpiece, increasing the cooling capacity of the stainless steel workpiece while reducing the cooling capacity of the copper-nickel alloy workpiece, thereby reducing the temperature difference between the two sides of the molten pool during laser welding and achieving excellent welding.

[0016] Furthermore, a buffer chamber is provided at the lower part of the blowing protection chamber, and the buffer chamber includes a first buffer chamber and a second buffer chamber, a wedge-shaped partition is provided between the first buffer chamber and the second buffer chamber, and the upper ends of the first buffer chamber and the second buffer chamber are both provided with evenly distributed air holes, the first buffer chamber is connected to the first blowing protection chamber through the air holes, and the second buffer chamber is connected to the second blowing protection chamber through the air holes.

[0017] This structure can not only enable the low-speed shielding gas to protect the welding surface and heat-affected zone, but also prevent the high-speed shielding gas from affecting the molten pool. The wedge-shaped partition can not only separate the two shielding gases, but also allow the two shielding gases to mix naturally in a small amount before being ejected from the buffer cavity, thereby avoiding the two shielding gases from intense mixing in the welding molten zone, which affects the welding quality.

[0018] Furthermore, the gas protection device further includes a follow-up protection gas cavity, which is used to spray a third protection gas toward the heat-affected zone of the welding workpiece.

[0019] This setting can prevent the welding heat affected zone of the workpiece from being affected by the surrounding environment and improve the welding quality.

[0020] Furthermore, a third conduit is provided at the upper end of the follower protective gas cavity and a screen is provided at the lower end. The third conduit is connected to an external gas supply device through a pipeline, and the screen is used to spray the third protective gas evenly onto the workpiece surface.

[0021] This structure can prevent the heat-affected zone of the welding workpiece following the lower part of the protective gas cavity from being affected by the surrounding environment.

[0022] Furthermore, the first protective gas and the third protective gas are nitrogen, and the second protective gas is argon.

[0023] Nitrogen has high thermal conductivity. Using nitrogen to blow sideways and protect one side of the stainless steel workpiece can prevent the temperature on one side of the stainless steel workpiece from being too high. At the same time, nitrogen is used to reduce the porosity in laser welding. Using argon to blow sideways and protect one side of the copper-nickel alloy workpiece can ensure that the alloy elements are not oxidized. Using nitrogen to protect the heat-affected zone of the welded workpiece can not only quickly cool the workpiece, but also prevent the heat-affected zone of the welded workpiece from being affected by the surrounding environment.

[0024] Furthermore, the nitrogen shielding gas velocity ejected from the first outlet and the screen is 10 to 15 L / min, and the argon shielding gas velocity ejected from the second outlet is 10 to 15 L / min.

[0025] This setting can not only enable the shielding gas to protect the weld surface and heat-affected zone, but also prevent high-speed shielding gas from impacting the molten pool and affecting the welding quality.

[0026] A process for laser welding a copper-nickel alloy and stainless steel, comprising:

[0027] Step 1: Input the plate thickness information α of the copper-nickel alloy workpiece and the stainless steel workpiece to be welded into the control device. If α≤X, proceed to step 2; if α>X, proceed to step 3;

[0028] Step 2: The minimum focal size of the laser welding gun is D, the deflection amplitude on the stainless steel workpiece side is: La = 0.5D, and the deflection amplitude on the copper-nickel alloy workpiece side is: Tc = 1 to 1.5D. At this time, the total swing amplitude of the laser welding gun is: La + Tc = 1.5 to 2.5D, the welding speed is A2 to A3, and the laser swing frequency is f = B2 to B3;

[0029] Step 3: The minimum focus size of the laser welding gun is D, the deflection amplitude on the stainless steel workpiece side is: La=1D, and the deflection amplitude on the copper-nickel alloy workpiece side is: Tc=1.5~2D. At this time, the total swing amplitude of the laser welding gun is: La+Tc=2.5~3.5D, the welding speed is A1~A2, and the laser swing frequency is f=B1~B2; wherein X is the set plate thickness information. In steps 2 and 3, the gas protection device sprays nitrogen to one side of the stainless steel workpiece and argon to one side of the copper-nickel alloy workpiece, and at the same time sprays nitrogen to the heat-affected zone of the workpiece through the screen, and the gas protection device and the laser welding gun have the same movement speed in the welding direction.

[0030] This welding process can easily offset the heat loss caused by the high thermal conductivity of copper-nickel alloy and reduce the temperature difference between the stainless steel workpiece and the copper-nickel alloy workpiece.

[0031] Furthermore, 4mm≤X≤6mm, 400mm / min≤A1≤600mm / min, 1400mm / min≤A2≤1600mm / min, 2400mm / min≤A3≤2600mm / min, 80Hz≤B1≤120Hz, 180Hz≤B2≤220Hz, 280Hz≤B3≤320Hz.

[0032] This setting enables the laser welding gun to use different welding speeds and oscillation frequencies when welding workpieces of different plate thicknesses, which can not only make the weld well-formed, but also increase the welding speed.

[0033] Furthermore, the distance between the front end face of the gas protection device and the focus of the laser welding gun is Y, the distance between the lower end face of the gas protection device and the welding surface of the workpiece is Z, and 5mm≤Y≤10mm, 0.5mm≤Z≤1mm.

[0034] This setting enables the shielding gas sprayed from the gas shielding device to cover the welding molten area, preventing the welding area and the heat-affected zone from being affected by the surrounding environment. It can also avoid scratches between the gas shielding device and the surface of the welding area, making it easier for the shielding gas in the shielding gas cavity to be sprayed through the screen to the workpiece surface.

[0035] Compared with the existing technology, the copper-nickel alloy and stainless steel laser welding device and process described in the present invention have the following advantages:

[0036] 1) The gas shielding device sprays a first shielding gas onto the weld surface and heat-affected zone on one side of the stainless steel workpiece, sprays a second shielding gas onto the weld surface and heat-affected zone on the side of the copper-nickel alloy workpiece, and simultaneously sprays a third shielding gas onto the heat-affected zone of the welded workpiece following the lower portion of the shielding gas cavity. This can effectively reduce the temperature difference between the two sides of the molten pool during welding, stabilize the pores generated during laser welding, reduce defects such as burn-through and undercutting during welding, and simultaneously reduce process-related pores generated during welding, thereby reducing porosity.

[0037] 2) The control device can control the laser welding gun to execute different swinging motion trajectories according to the thickness of the welding workpiece, thereby achieving precise distribution of laser welding energy on the stainless steel side and the copper-nickel alloy side. The swinging laser can also ensure the melting amount on one side of the copper-nickel alloy workpiece, avoiding thermal cracks due to imbalance in the fusion ratio. At the same time, it can also increase the stirring of the molten pool, promote the escape of pores, enable the weld to be well formed, optimize the composition of the weld joint, and refine the grains. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic structural diagram of a laser welding device according to an embodiment of the present invention;

[0039] Figure 2 for Figure 1 A partial enlarged schematic diagram of point A in the middle;

[0040] Figure 3 for Figure 1 Schematic diagram of the structure of the gas protection device;

[0041] Figure 4 for Figure 3 Schematic diagram of the structure of the gas protection device from the second perspective;

[0042] Figure 5 for Figure 3 A schematic diagram of the structure of the gas protection device from the third perspective;

[0043] Figure 6 for Figure 3 Schematic diagram of the structure of the gas protection device from the fourth perspective;

[0044] Figure 7This is a trajectory diagram of laser welding according to an embodiment of the present invention;

[0045] Figure 8 This is a schematic diagram of frontal radiographic inspection of a weld according to Example 3 of the present invention;

[0046] Figure 9 This is a schematic diagram of back-side radiographic inspection of a weld according to Example 3 of the present invention;

[0047] Figure 10 Schematic diagram of DR ray detection of the weld described in Example 3 of the present invention.

[0048] Description of reference numerals:

[0049] 1. Laser emitting device; 10. Laser; 11. Laser welding gun; 12. Optical fiber; 2. Gas protection device; 3. Control device; 4. Air blowing protection chamber; 41. First air blowing protection chamber; 410. First conduit; 411. First outlet; 42. Second air blowing protection chamber; 420. Second conduit; 421. Second outlet; 43. Buffer chamber; 431. First buffer chamber; 432. Second buffer chamber; 44. Wedge-shaped partition; 45. Vent; 5. Follow-up protective gas chamber; 51. Third conduit; 52. Screen; 6. Bracket; 81. First protective gas; 82. Second protective gas; 83. Third protective gas; 91. Stainless steel workpiece; 92. Copper-nickel alloy workpiece; 100. Weld. DETAILED DESCRIPTION

[0050] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0051] Example 1

[0052] like Figures 1 to 7 As shown, a copper-nickel alloy and stainless steel laser welding device includes

[0053] Laser emitting device 1, gas protection device 2 and control device 3;

[0054] The laser emitting device 1 includes a laser welding gun 11 and an optical fiber 12. The optical fiber 12 is used to provide energy to the laser welding gun 11. The laser welding gun 11 is used to emit laser light 10 to weld the workpiece.

[0055] The gas protection device 2 includes an air blowing protection chamber 4, which includes a first air blowing protection chamber 41 and a second air blowing protection chamber 42. The first air blowing protection chamber 41 is used to spray a first protective gas 81 toward one side of the stainless steel workpiece 91, and the second air blowing protection chamber 42 is used to spray a second protective gas 82 toward one side of the copper-nickel alloy workpiece 92.

[0056] The control device 3 is used to control the operating parameters and movement trajectories of the laser emitting device 1 and the gas protection device 2 .

[0057] The copper-nickel alloy and stainless steel laser welding device described in the present application, during the laser welding process, sprays a first shielding gas 81 on the weld 100 surface and the heat-affected zone on one side of the stainless steel workpiece 91 through the gas shielding device 2, and sprays a second shielding gas 82 on the weld 100 surface and the heat-affected zone on the side of the copper-nickel alloy workpiece 92. This structure can effectively reduce the temperature difference on both sides of the molten pool during welding, reduce the process pores generated during welding, and reduce the porosity. By controlling the operating parameters and activity trajectory of the laser emitting device 1 and the gas shielding device 2, it is possible to further achieve precise distribution of laser welding energy on the stainless steel workpiece 91 side and the copper-nickel alloy workpiece 92 side, avoid thermal cracks due to imbalance in the fusion ratio, and achieve good forming of the weld.

[0058] Preferably, the laser welding gun 11 is a galvanometer welding gun or a laser welding gun with at least one-dimensional swing function.

[0059] As a preferred example of the present invention, a first conduit 410 is provided at the upper end of the first air blowing protection chamber 41, and a first outlet 411 is provided at the front end. The first conduit 410 is connected to an external gas supply device through a pipeline, and the first outlet 411 is used to spray the first protective gas 81 toward one side of the stainless steel workpiece 91. A second conduit 420 is provided at the upper end of the second air blowing protection chamber 42, and a second outlet 421 is provided at the front end. The second conduit 420 is connected to the external gas supply device through a pipeline, and the second outlet 421 is used to spray the second protective gas 82 toward one side of the copper-nickel alloy workpiece 92.

[0060] Specifically, the first outlet 411 is used to spray the first shielding gas 81 toward one side of the stainless steel workpiece 91, and the second outlet 421 is used to spray the second shielding gas 82 toward one side of the copper-nickel alloy workpiece 92. This structure can simultaneously spray different types of shielding gases toward both the stainless steel workpiece 91 and the copper-nickel alloy workpiece 92, thereby increasing the cooling capacity of the stainless steel workpiece 91 and reducing the cooling capacity of the copper-nickel alloy workpiece 92, thereby reducing the temperature difference between the two sides of the molten pool during laser welding and achieving excellent welding.

[0061] Preferably, the control device 3 is electrically connected to the external gas supply device and the laser emitting device 1 respectively, so as to realize real-time control of the operating parameters of the gas protection device 2 and the laser emitting device 1 .

[0062] As a preferred example of the present invention, a buffer chamber 43 is provided at the lower part of the blowing protection chamber 4, and the buffer chamber 43 includes a first buffer chamber 431 and a second buffer chamber 432. A wedge-shaped partition 44 is provided between the first buffer chamber 431 and the second buffer chamber 432. The upper ends of the first buffer chamber 431 and the second buffer chamber 432 are both provided with evenly distributed air holes 45. The first buffer chamber 431 is connected to the first blowing protection chamber 41 through the air holes 45, and the second buffer chamber 432 is connected to the second blowing protection chamber 42 through the air holes 45.

[0063] Specifically, the first shielding gas 81 in the first air blowing shielding chamber 41 enters the first buffer chamber 431 through the air vent 45, decelerates after colliding with the workpiece surface, and is ejected from the front end of the first buffer chamber 431. The second shielding gas 82 in the second air blowing shielding chamber 42 enters the second buffer chamber 432 through the air vent 45, decelerates after colliding with the workpiece surface, and is ejected from the front end of the second buffer chamber 432. The low-speed shielding gas ejected from the front ends of the first buffer chamber 431 and the second buffer chamber 432 is close to the welding surface of the workpiece, and the high-speed shielding gas ejected from the first outlet 411 and the second outlet 421 is located at the upper end of the low-speed shielding gas. This structure can not only enable the low-speed shielding gas to protect the welding surface and the heat-affected zone, but also prevent the high-speed shielding gas from affecting the molten pool. The wedge-shaped partition 44 can not only separate the two shielding gases, but also enable the two shielding gases to be naturally mixed in small amounts before ejecting the buffer chamber 43, so as to prevent the two shielding gases from being violently mixed in the welding molten zone and affecting the welding quality.

[0064] As a preferred example of the present invention, the gas protection device 2 further includes a follow-up protection gas cavity 5, and the follow-up protection gas cavity 5 is used to spray a third protection gas 83 toward the heat-affected zone of the welding workpiece.

[0065] Specifically, this arrangement can prevent the welding heat-affected zone of the workpiece from being affected by the surrounding environment, thereby improving the welding quality.

[0066] As a preferred example of the present invention, the upper end of the follow-up protective gas cavity 5 is provided with a third conduit 51, and the lower end is provided with a screen 52. The third conduit 51 is connected to the external air supply device through a pipeline, and the screen 52 is used to make the third protective gas 83 spray evenly onto the workpiece surface.

[0067] Specifically, this structure can prevent the heat-affected zone of the welding workpiece below the protective gas cavity 5 from being affected by the surrounding environment.

[0068] As a preferred example of the present invention, the screen 52 is provided with evenly distributed through holes, and the through holes enable the third shielding gas 83 to be evenly sprayed toward the workpiece.

[0069] Specifically, this structure can evenly divide the third shielding gas in the follow-up shielding gas cavity 5 into uniform-speed shielding gas that is sprayed toward the workpiece, thereby preventing the heat-affected zone of the welded workpiece from being affected by the surrounding environment.

[0070] Preferably, the diameter of the through hole is set to 0.5 mm.

[0071] As a preferred example of the present invention, the first protective gas 81 and the third protective gas 83 are nitrogen, and the second protective gas 82 is argon.

[0072] Specifically, nitrogen has high thermal conductivity. Using nitrogen to blow sideways and protect one side of the stainless steel workpiece can prevent the temperature on one side of the stainless steel workpiece 91 from being too high. At the same time, using nitrogen to reduce the porosity in laser welding, using argon to blow sideways and protect one side of the copper-nickel alloy workpiece 92 can ensure that the alloy elements are not oxidized. Using nitrogen to protect the heat-affected zone of the welded workpiece can not only quickly cool the workpiece, but also prevent the heat-affected zone of the welded workpiece from being affected by the surrounding environment.

[0073] As a preferred example of the present invention, the nitrogen shielding gas velocity ejected from the first outlet 411 and the screen 52 is 10-15 L / min, and the argon shielding gas velocity ejected from the second outlet 421 is 10-15 L / min.

[0074] Specifically, this setting can not only enable the shielding gas to protect the weld 100 surface and the heat-affected zone, but also prevent the high-speed shielding gas from impacting the molten pool and affecting the welding quality.

[0075] As a preferred example of the present invention, a bracket 6 is provided at the upper end of the gas protection device 2 , and the bracket 6 is used to fix the gas protection device 2 .

[0076] Specifically, this arrangement enables the gas protection device 2 to move along the weld 100 during laser welding, thereby facilitating protection of the welding surface.

[0077] Example 2

[0078] like Figures 1 to 7 As shown, a process for a copper-nickel alloy and stainless steel laser welding device includes:

[0079] Step 1: Input the plate thickness information α of the copper-nickel alloy workpiece 92 and the stainless steel workpiece 91 to be welded into the control device 3. If α≤X, proceed to step 2; if α>X, proceed to step 3;

[0080] Step 2: The minimum focal size of the laser welding gun 11 is D. The deflection amplitude on the stainless steel workpiece 91 side is: La=0.5D, and the deflection amplitude on the copper-nickel alloy workpiece 92 side is: Tc=1-1.5D. At this time, the total swing amplitude of the laser welding gun 11 is: La+Tc=1.5-2.5D. At this time, the laser energy obtained on the copper-nickel alloy workpiece 92 side is 2-3 times that on the stainless steel workpiece 91 side. This welding process is convenient for offsetting the heat loss caused by the high thermal conductivity of the copper-nickel alloy and reducing the temperature difference between the stainless steel workpiece 91 side and the copper-nickel alloy workpiece 92. At this time, the welding speed is A2-A3, and the laser swing frequency is set to f=B2-B3.

[0081] Step 3: The minimum focal size of the laser welding gun 11 is D. As the plate thickness increases, the high thermal conductivity of the copper-nickel alloy side becomes more obvious. It is necessary to further increase the energy density of the copper-nickel alloy workpiece 92. At this time, the deflection amplitude of the stainless steel workpiece 91 side is set to: La = 1D, and the deflection amplitude of the copper-nickel alloy workpiece 92 is set to: Tc = 1.5~2D. At this time, the total swing amplitude of the laser welding gun 11 is: La+Tc=2.5~3.5D. The copper-nickel alloy workpiece 92 will obtain a larger laser energy density, which helps to reduce the temperature difference between the stainless steel workpiece 91 side and the copper-nickel alloy workpiece 92. At this time, the welding speed is A1~A2, and the laser swing frequency is set to f=B1~B2;

[0082] Among them, X is the set plate thickness information, A1, A2, A3 are welding speeds, B1, B2, B3 are laser oscillation frequencies, 4mm≤X≤6mm, 400mm / min≤A1≤600mm / min, 1400mm / min≤A2≤1600mm / min, 2400mm / min≤A3≤2600mm / min, 80Hz≤B1≤120Hz, 180Hz≤B2≤220Hz, 280Hz≤B3≤320Hz. This setting enables the laser welding gun 11 to adopt different welding speeds and oscillation frequencies when welding workpieces with different plate thicknesses, which can not only make the weld well-formed, but also increase the welding speed.

[0083] Preferably, X is 5 mm, A1 is 500 mm / min, A2 is 1500 mm / min, A3 is 2500 mm / min, B1 is 100 Hz, B2 is 200 Hz, and B3 is 300 Hz.

[0084] In steps 2 and 3, the gas protection device 2 sprays nitrogen toward one side of the stainless steel workpiece 91 and sprays argon toward one side of the copper-nickel alloy workpiece 92, and at the same time sprays nitrogen toward the heat-affected zone of the workpiece through the screen 52, and the gas protection device 2 and the laser welding gun 11 have the same moving speed in the welding direction.

[0085] Preferably, in step 2 and step 3, a laser welding gun with a one-dimensional swing function is selected.

[0086] Preferably, the distance between the focus of the laser welding gun 11 and the front end face of the gas protection device 2 is Y, 5mm≤Y≤10mm. This setting enables the protective gas sprayed by the gas protection device 2 to cover the welding melting area, avoiding the welding area and the heat-affected zone from being affected by the surrounding environment.

[0087] Preferably, the distance between the lower end face of the gas protection device 2 and the welding surface of the workpiece is Z, 0.5mm≤Z≤1mm. This setting can not only avoid scratches between the gas protection device 2 and the surface of the welding area, but also facilitate the protective gas in the protective gas cavity 5 to be sprayed onto the workpiece surface through the screen 52.

[0088] Example 3

[0089] like Figures 1 to 10 As shown, 10mm thick, B10+316 dissimilar metal laser welding is adopted, "I" type groove, flat welding position narrow gap welding is adopted, the first blowing protection chamber 41 sprays 10~15L / min of N2 to the 316 side for side blowing and protection, the second blowing protection chamber 42 sprays 10~15L / min of Ar to the B10 side for side blowing and protection, and the following protection gas chamber 5 sprays 10~15L / min of Ar to the heat affected zone of the welding workpiece for follow-up protection. At the same time, a laser welding gun with a minimum focus size D = 0.4mm, La = 1D, and the copper-nickel alloy side swing amplitude is: Tc = 2D. At this time, the total swing amplitude of the welding gun is: La + Tc = 3D, the laser power is: 11000W, the laser swing frequency f = 100 ~ 200Hz, the welding speed is 600mm / min ~ 800mm / min, and the welding effect is excellent. After welding, according to the NB / T47013 level II radiographic inspection, no undercuts and cracks were found.

[0090] In summary, the copper-nickel alloy and stainless steel laser welding device and process described in the present application, during the laser welding process, on the one hand, the gas protection device 2 is used to spray the first shielding gas 81 on the weld seam 100 surface and the heat-affected zone on one side of the stainless steel workpiece, and the second shielding gas 82 is sprayed on the weld seam 100 surface and the heat-affected zone on the copper-nickel alloy workpiece, and at the same time, the third shielding gas 83 is sprayed on the heat-affected zone of the welding workpiece following the lower part of the shielding gas cavity 5. On the other hand, the control device 3 can control the laser welding gun 11 to perform different swinging motion trajectories according to the plate thickness of the welding workpiece, so as to realize The laser welding energy is now precisely distributed on the stainless steel side and the copper-nickel alloy side. This structure can effectively reduce the temperature difference on both sides of the molten pool during welding, stabilize the pores generated during laser welding, reduce defects such as burn-through and undercut during welding, and at the same time reduce the process-related pores generated during welding and reduce the porosity. The swinging laser can also ensure the melting amount on one side of the copper-nickel alloy workpiece 92, avoid thermal cracks due to imbalance in the fusion ratio, and increase the stirring of the molten pool, promote the escape of pores, enable the weld to be well formed, optimize the composition of the weld joint, and refine the grains.

[0091] Although the present invention is disclosed as above, the present invention 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 invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A copper-nickel alloy and stainless steel laser welding device, characterized in that: It comprises a laser emitting device (1), a gas protection device (2) and a control device (3); The laser emitting device (1) comprises a laser welding gun (11) and an optical fiber (12), wherein the optical fiber (12) is used to provide energy to the laser welding gun (11), and the laser welding gun (11) is used to emit laser light (10) to weld a workpiece; The gas protection device (2) comprises an air blowing protection chamber (4), wherein the air blowing protection chamber (4) comprises a first air blowing protection chamber (41) and a second air blowing protection chamber (42), wherein the first air blowing protection chamber (41) is used to spray a first protection gas (81) toward one side of a stainless steel workpiece (91), and the second air blowing protection chamber (42) is used to spray a second protection gas (82) toward one side of a copper-nickel alloy workpiece (92); The first air blowing protection chamber (41) is provided with a first conduit (410) at the upper end and a first outlet (411) at the front end. The first conduit (410) is connected to an external air supply device through a pipeline. The first outlet (411) is used to spray a first protective gas (81) toward one side of the stainless steel workpiece (91). The second air blowing protection chamber (42) is provided with a second conduit (420) at the upper end and a second outlet (421) at the front end. The second conduit (420) is connected to an external air supply device through a pipeline. The second outlet (421) is used to spray a second protective gas (82) toward one side of the copper-nickel alloy workpiece (92). A buffer chamber (43) is provided at the lower portion of the air blowing protection chamber (4), the buffer chamber (43) comprising a first buffer chamber (431) and a second buffer chamber (432), a wedge-shaped partition (44) being provided between the first buffer chamber (431) and the second buffer chamber (432), and evenly distributed vents (45) being provided at the upper ends of the first buffer chamber (431) and the second buffer chamber (432), the first buffer chamber (431) being in communication with the first air blowing protection chamber (41) through the vents (45), and the second buffer chamber (432) being in communication with the second air blowing protection chamber (42) through the vents (45); The control device (3) is used to control the operating parameters and activity tracks of the laser emitting device (1) and the gas protection device (2).

2. The copper-nickel alloy and stainless steel laser welding device according to claim 1, characterized in that: The gas protection device (2) further comprises a follow-up protection gas cavity (5), and the follow-up protection gas cavity (5) is used to spray a third protection gas (83) toward the heat-affected zone of the welding workpiece.

3. The copper-nickel alloy and stainless steel laser welding device according to claim 2, characterized in that: The upper end of the follower protective gas cavity (5) is provided with a third conduit (51), and the lower end is provided with a screen (52). The third conduit (51) is connected to an external air supply device through a pipeline, and the screen (52) is used to make the third protective gas (83) spray evenly onto the workpiece surface.

4. The copper-nickel alloy and stainless steel laser welding device according to claim 3, characterized in that: The first protective gas (81) and the third protective gas (83) are nitrogen, and the second protective gas (82) is argon.

5. The copper-nickel alloy and stainless steel laser welding device according to claim 4, characterized in that: The nitrogen protection gas velocity ejected from the first outlet (411) and the screen (52) is 10 to 15 L / min, and the argon protection gas velocity ejected from the second outlet (421) is 10 to 15 L / min.

6. A process based on the copper-nickel alloy and stainless steel laser welding device according to claim 5, characterized in that: include: Step 1: Inputting the plate thickness information α of the copper-nickel alloy workpiece (92) and the stainless steel workpiece (91) to be welded into the control device (3); if α≤X, proceeding to step 2; if α>X, proceeding to step 3; Step 2, the minimum focal size of the laser welding gun (11) is D, the deflection amplitude on one side of the stainless steel workpiece (91) is: La=0.5D, and the deflection amplitude on one side of the copper-nickel alloy workpiece (92) is: Tc=1~1.5D. At this time, the total swing amplitude of the laser welding gun (11) is: La+Tc=1.5~2.5D, the welding speed is A2~A3, and the laser swing frequency is f=B2~B3; Step 3: The minimum focal size of the laser welding gun (11) is D, the deflection amplitude on one side of the stainless steel workpiece (91) is: La=1D, and the deflection amplitude on one side of the copper-nickel alloy workpiece (92) is: Tc=1.5~2D. At this time, the total swing amplitude of the laser welding gun (11) is: La+Tc=2.5~3.5D, the welding speed is A1~A2, and the laser swing frequency is f=B1~B2; Wherein, X is the set plate thickness information. In steps 2 and 3, the gas protection device (2) sprays nitrogen toward one side of the stainless steel workpiece (91) and sprays argon toward one side of the copper-nickel alloy workpiece (92), and simultaneously sprays nitrogen toward the heat-affected zone of the workpiece through the screen (52), and the moving speed of the gas protection device (2) and the laser welding gun (11) in the welding direction is the same.

7. The process of the copper-nickel alloy and stainless steel laser welding device according to claim 6, characterized in that: 4mm ≤ 8. The process of the copper-nickel alloy and stainless steel laser welding device according to claim 6, characterized in that: The distance between the front end face of the gas protection device (2) and the focus of the laser welding gun (11) is Y, the distance between the lower end face of the gas protection device (2) and the welding surface of the workpiece is Z, and 5mm≤Y≤10mm, 0.5mm≤Z≤1mm.

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