Laser welding method for brass workpieces and phosphor bronze workpieces

Abstract

The present application discloses a laser welding method for brass workpieces and phosphor bronze workpieces. The method includes the steps of: assembling the brass workpiece and the phosphor bronze workpiece onto a welding jig, the brass workpiece and the phosphor bronze workpiece; using nanosecond green light to weld the brass workpiece and the phosphor bronze workpiece, the wavelength of the nanosecond green light being 510 - 535 nm and the pulse width being 195 - 1050 ns; the average output power of the laser being 30 - 55 W, the welding speed being 45 - 85 mm / s, and the laser focus position being 0 to -0.3 mm. The laser welding method for brass workpieces and phosphor bronze workpieces of the present application has a simple process, high production efficiency, small heat influence on the solder joint edge, stable tensile force, high metal bonding strength, and is economical and applicable.

Description

Technical Field

[0001] This application relates to the technical field of metal welding, and particularly to a laser welding method for brass workpieces and phosphor bronze workpieces. Background Art

[0002] Brass and phosphor bronze have gradually become important materials in the fields of consumer electronics and precision parts due to their good thermal and electrical conductivity, and the proportion of copper structural parts used in the related products has also increased significantly. For example, a welded structural part of a brass workpiece and a phosphor bronze workpiece is required in a mobile phone camera. In the prior art, the welding of brass workpieces and phosphor bronze workpieces has problems such as complex process, low welding quality, low welding strength, and high welding cost. Summary of the Invention

[0003] To solve the above technical problems, this application provides a laser welding method for brass workpieces and phosphor bronze workpieces, which has the advantages of simple process, high production efficiency, small heat influence on the solder joint edge, stable tensile force, high metal bonding strength, and being economical and applicable.

[0004] To achieve this purpose, this application adopts the following technical solutions:

[0005] A laser welding method for brass workpieces and phosphor bronze workpieces, comprising the steps of:

[0006] Assembling the brass workpiece and the phosphor bronze workpiece onto a welding jig;

[0007] Welding the brass workpiece and the phosphor bronze workpiece with nanosecond green light, the wavelength of the nanosecond green light is 510 - 535 nm, and the pulse width is 195 - 1050 ns; the average output power of the laser is 30 - 55 W, the welding speed is 45 - 85 mm / s, and the laser focus position is 0 - -0.3 mm.

[0008] As an alternative to the above laser welding method for brass workpieces and phosphor bronze workpieces, the thickness of the brass workpiece is 0.08 - 0.12 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.3 mm;

[0009] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 200 KHz, and the pulse width is 1000 ns; the laser welding parameters are: spiral points, the filling spacing is 0.02 - 0.03 mm; or, rectangular frame points, the filling spacing is 0.015 - 0.035 mm; the solder joint diameter is 0.35 - 0.45 mm; the average output power of the laser is 35 - 38 w, the welding speed is 60 - 80 mm / s, and the laser focus position is 0 - -0.3 mm.

[0010] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the thickness of the brass workpiece is 0.12 - 0.14 mm, and the phosphor bronze workpiece is 0.2 - 0.4 mm;

[0011] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 250 - 350 KHz, and the pulse width is 500 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm; or, rectangular frame points, the filling spacing is 0.015 - 0.035 mm; the solder joint diameter is 0.35 - 0.45 mm; the average laser output power is 37 - 42 w, the welding speed is 50 - 70 mm / s, and the laser focus position is 0 - -0.3 mm.

[0012] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the thickness of the brass workpiece is 0.14 - 0.16 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.5 mm;

[0013] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 1000 KHz, and the pulse width is 200 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm; or, rectangular frame points, the filling spacing is 0.01 - 0.03 mm; the solder joint diameter is 0.35 - 0.45 mm; the average laser output power is 40 - 50 w, the welding speed is 50 - 80 mm / s, and the laser focus position is 0 - -0.3 mm.

[0014] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the wavelength of the nanosecond green light is 532 nm.

[0015] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, during welding, the brass workpiece is on the upper layer and the phosphor bronze workpiece is on the lower layer, and the assembly gap between the brass workpiece and the phosphor bronze workpiece is less than 1 / 10 of the thickness of the brass workpiece on the upper layer.

[0016] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the scheme of the laser welding method for the brass workpiece and the phosphor bronze workpiece further includes the steps:

[0017] Determine the focus: Place the workpiece to be welded on the welding processing plane, use the laser to make multiple solder joints with different foci on the workpiece to be welded, and determine the focus position selected during welding by detecting the appearance and quality of the multiple solder joints.

[0018] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the steps of determining the focus specifically include:

[0019] Place the workpiece to be welded on the welding processing plane;

[0020] Make a Z on the workpiece to be welded +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 Seven solder joints, where the focus position of the solder joint Z0 is 0, and from the solder joint Z0 to Z +3 The focus gradually shifts upward, and from the solder joint Z0 to Z -3 The focus gradually shifts downward;

[0021] By detecting the appearance and quality of the solder joints Z +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 Determine the focus position selected during welding.

[0022] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the welding strength between the brass workpiece and the phosphor bronze workpiece is: the welding strength of 3 solder joints is greater than or equal to 80 N, and the welding strength of 15 solder joints is greater than or equal to 400 N.

[0023] As an alternative to the laser welding method for the above-mentioned brass workpiece and phosphor bronze workpiece, the model of the brass workpiece is C2600, and the model of the phosphor bronze workpiece is C5191.

[0024] The beneficial effects of the embodiments of the present application are as follows: By studying the welding process parameters suitable for brass workpieces and phosphor bronze workpieces, the existing welding process is simplified. There is no need to add protective gases such as nitrogen and argon, and there is no need to fill welding materials such as welding wires and welding consumables. It has high economic benefits, simple process, and high production efficiency. When using the laser welding method for brass workpieces and phosphor bronze workpieces of the present invention for welding, the single-pulse output energy is low, the laser peak power is high, the laser beam quality is good, the appearance of the solder joints is good, there is no obvious splash at the edges, the heat-affected area at the edges of the solder joints is small, the overall deformation of the welded product is small, the solder joints are firm, the reliability is high, the tensile force is stable, the heat input and output are small, and the welding energy and control accuracy are relatively high. The welding strength of the upper and lower layers of dissimilar metals is high, and there are no welding defects such as cracks and pores in the weld joint layer, which can meet the application requirements of the welded product, and the welding effect of dissimilar metals is good. Brief Description of the Drawings

[0025] Figure 1 Is a flowchart of the laser welding method for brass workpieces and phosphor bronze workpieces in an embodiment of the present application;

[0026] Figure 2 Is a schematic structural diagram of a brass workpiece in an embodiment of the present application;

[0027] Figure 3 It is a schematic structural diagram of a phosphor bronze workpiece in an embodiment of the present application;

[0028] Figure 4 It is a schematic structural diagram of the welding of a brass workpiece and a phosphor bronze workpiece in an embodiment of the present application;

[0029] Figure 5 It is a schematic diagram of a welding spiral trajectory in an embodiment of the present application;

[0030] Figure 6 It is a schematic diagram of a welding spiral trajectory in an embodiment of the present application;

[0031] Figure 7 It is a micrograph of the cross-section of a spiral spot weld under a metallurgical microscope in an embodiment of the present application;

[0032] Figure 8 It is a micrograph of the cross-section of a rectangular frame spot weld under a metallurgical microscope in an embodiment of the present application.

[0033] In the figure:

[0034] 101, brass workpiece; 201, phosphor bronze workpiece. Specific embodiments

[0035] The following further describes the present application in detail with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the present application, rather than limiting the present application. In addition, it should be noted that for the sake of description, only parts related to the present application are shown in the drawings, rather than all the structures.

[0036] Please refer to Figure 1 , in the embodiment of the present application, the laser welding method for a brass workpiece and a phosphor bronze workpiece includes the following steps:

[0037] S100, Assemble the brass workpiece and the phosphor bronze workpiece onto the welding jig;

[0038] S200, Weld the brass workpiece and the phosphor bronze workpiece using a nanosecond green light. The wavelength of the nanosecond green light is 510 - 535 nm, and the pulse width is 195 - 1050 ns; the average output power of the laser is 30 - 55 W, the welding speed is 45 - 85 mm / s, and the laser focus position is 0 - -0.3 mm.

[0039] Refer to Figures 2 to 4 , Figure 2 shows a schematic structural diagram of the brass workpiece 101, Figure 3 shows a schematic structural diagram of the phosphor bronze workpiece 201. As Figure 4As shown, during welding, the brass workpiece 101 can be placed above the phosphor bronze workpiece 201, and the laser is emitted from top to bottom to weld the brass workpiece 101 and the phosphor bronze workpiece 201. In the embodiment of the present application, the structural part after welding the brass workpiece 101 and the phosphor bronze workpiece 201 is a part used in a mobile phone camera. In this structural part, the model of the brass material used for the brass workpiece 101 is C2600 nickel-plated, and the model of the phosphor bronze material used for the phosphor bronze workpiece 201 is C5191 nickel-plated.

[0040] In the embodiment of the present application, an ns (nanosecond)-level laser light source is adopted, and the welding heat influence of the ns-level laser light source is relatively small. At the same time, by using the above laser wavelength and laser processing parameters, the single-pulse energy during processing is less than or equal to 450 μJ, the single-pulse output energy is low, the laser peak power is high, the laser beam quality is good, the appearance of the solder joint is good, there is no obvious splash at the edge, the heat-affected area at the edge of the solder joint is small, the overall deformation of the welded product is small, the solder joint is firm, the reliability is high, the tensile force is stable, the heat input and output are small, and the welding energy and control accuracy are relatively high. The laser welding method for the brass workpiece and the phosphor bronze workpiece in the embodiment of the present application does not require additional protective gases such as nitrogen and argon, and does not require welding materials such as filler wires and welding consumables, thus simplifying the existing welding process, with high economic benefits and high production efficiency. After welding, the welding strength of the upper and lower dissimilar metals is high, and there are no welding defects such as cracks and pores in the weld joint layer, which can meet the application requirements of the welded product, and the welding effect of the dissimilar metals has great advantages.

[0041] Embodiment 1

[0042] The thickness of the brass workpiece for welding is 0.08 - 0.12 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.3 mm;

[0043] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 200 KHz, and the pulse width is 1000 ns; the laser welding parameters are: spiral dots, the filling spacing is 0.02 - 0.03 mm; or, rectangular frame dots, the filling spacing is 0.015 - 0.035 mm; the diameter of the solder joint is 0.35 - 0.45 mm; the average output power of the laser is 35 - 38 W, the welding speed is 60 - 80 mm / s, and the laser focus position is 0 - -0.3 mm.

[0044] In the embodiment of the present application, a nanosecond green light with a wavelength of 532 nm is used as the light source, so that the welding of the brass workpiece and the phosphor bronze workpiece achieves a good welding effect. The phosphor bronze workpiece has a high absorption rate and a low reflectivity for the green light source. In the embodiment of the present application, the energy absorbed by the nanosecond green light laser with a wavelength of 532 nm acting on the material surface is more than 20 times that of the red light laser with a wavelength of 1064 nm. In the embodiment of the present application, the heat-affected zone at the edge of the solder joint is small. The above spiral dots and rectangular frame dots can be referred to Figure 5 andFigure 6 During laser welding, the laser head can move spirally outward along the Figure 5 spiral trajectory shown, or it can move spirally outward along the Figure 6 rectangular frame-shaped trajectory shown. The laser head moves along the trajectory. After completing one spiral trajectory, a solder joint is formed. The distance between the two spiral lines in the spiral trajectory is the filling distance.

[0045] More specifically, the thickness of the brass workpiece is 0.1 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.3 mm;

[0046] The laser waveform is a square wave, the laser wavelength is 532 nm, the laser repetition frequency is 200 KHz, and the pulse width is 1000 ns; the laser welding parameters are: spiral points, the filling distance is 0.02 - 0.03 mm, 2 inner circles, 1 outer circle, the solder joint diameter is 0.35 - 0.45 mm, and the spiral direction is from the inside to the outside; if rectangular frame points are used, the filling distance is 0.015 - 0.035 mm, and other parameters are the same as those of the spiral points; the average laser output power is 35 - 38 w, the welding speed is 60 - 80 mm / s, and the laser focus position is 0 - -0.3 mm.

[0047] Figure 7 is the morphology diagram of the cross-section of the spiral point solder joint under a metallurgical microscope in an embodiment of the present application. Figure 8 is the morphology diagram of the cross-section of the rectangular frame point solder joint under a metallurgical microscope in an embodiment of the present application. From Figure 7 and Figure 8 it can be seen that the appearance of the solder joint is good, there is no obvious splash at the edge, the heat affected area at the edge of the solder joint is small, the overall deformation of the welded product is small, there are no cracks and pores in the weld joint bonding layer, the solder joint is firm, and the tensile force is stable. Using the laser welding method of the present application, the welding strength between the brass workpiece and the phosphor bronze workpiece reaches: when welding 3 solder joints, the welding strength is greater than or equal to 80 N, and when welding 15 solder joints, the welding strength is greater than or equal to 400 N.

[0048] Preferably, during welding, referring to Figure 3 , the brass workpiece is placed above the phosphor bronze workpiece, with the brass workpiece on the upper layer and the phosphor bronze workpiece on the lower layer. The assembly gap between the brass workpiece and the phosphor bronze workpiece is less than 1 / 10 of the thickness of the brass workpiece located on the upper layer. During welding, the brass workpiece and the phosphor bronze workpiece are assembled on the fixture and locked by the locking device, so that the assembly gap between the brass workpiece and the phosphor bronze workpiece is less than 1 / 10 of the thickness of the brass workpiece, which can optimize the welding effect and welding quality.

[0049] Example Two

[0050] The thickness of the brass workpiece is 0.12 - 0.14 mm, and the phosphor bronze workpiece is 0.2 - 0.4 mm;

[0051] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 250 - 350 KHz, and the pulse width is 500 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm; or, rectangular frame points, the filling spacing is 0.015 - 0.035 mm; the solder joint diameter is 0.35 - 0.45 mm; the average laser output power is 37 - 42 w, the welding speed is 50 - 70 mm / s, and the laser focus position is 0 to -0.3 mm.

[0052] More specifically, the thickness of the brass workpiece is 0.13 mm, and the thickness of the lower layer phosphor bronze workpiece is 0.2 - 0.4 mm;

[0053] The laser waveform uses a square wave, the laser wavelength is 532 nm, the laser repetition frequency is 250 - 350 KHz, and the pulse width is 500 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm, 1.5 turns for the inner circle, 1 turn for the outer circle, the solder joint diameter is 0.35 - 0.45 mm, and the spiral direction is from the inside to the outside; if rectangular frame points are used, the filling spacing is 0.015 - 0.035 mm; the average laser output power is 37 - 42 w, the welding speed is 50 - 70 mm / s, and the laser focus position is 0 to -0.3 mm.

[0054] The cross-sectional morphology effect of the solder joint is similar to that in Embodiment 1 Figure 7 and Figure 8 similar. The strength of the solder joint is also similar to that in Embodiment 1. When welding 3 solder joints, the welding strength is greater than or equal to 80 N, and when welding 15 solder joints, the welding strength is greater than or equal to 400 N.

[0055] Embodiment 3

[0056] The thickness of the brass workpiece is 0.14 - 0.16 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.5 mm;

[0057] The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 1000 KHz, and the pulse width is 200 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm; or, rectangular frame points, the filling spacing is 0.01 - 0.03 mm; the solder joint diameter is 0.35 - 0.45 mm; the average laser output power is 40 - 50 w, the welding speed is 50 - 80 mm / s, and the laser focus position is 0 to -0.3 mm.

[0058] More specifically, the thickness of the brass workpiece is 0.15 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.5 mm;

[0059] The laser waveform is a square wave, the laser wavelength is 532 nm, the laser repetition frequency is 1000 KHz, and the pulse width is 200 ns; the laser welding parameters are: spiral points, the filling spacing is 0.01 - 0.025 mm, 2 inner circles, 1 outer circle, the solder joint diameter is 0.35 - 0.45 mm, and the spiral direction is from the inside to the outside; if rectangular frame points are used, the filling spacing is 0.01 - 0.03 mm; the average laser output power is 40 - 50 w, the welding speed is 50 - 80 mm / s, and the laser focus position is 0 - -0.3 mm.

[0060] The cross-sectional morphology effect of the solder joint is similar to that in Embodiment 1 Figure 7 and Figure 8 similar. The strength of the solder joint is also similar to that in Embodiment 1. When welding 3 solder joints, the welding strength is greater than or equal to 80 N, and when welding 15 solder joints, the welding strength is greater than or equal to 400 N.

[0061] The laser welding method for brass workpieces and phosphor bronze workpieces in the embodiments of the present application further includes the steps:

[0062] S1. Determine the focus: Place the workpiece to be welded on the welding processing plane, and use a laser to make multiple solder joints with different foci on the workpiece to be welded. By detecting the appearance and quality of the multiple solder joints, determine the focus position selected during welding.

[0063] Specifically, before welding, first determine the appropriate focus position to select a focus with better welding effect and exclude foci with slightly worse welding effect.

[0064] More specifically, the steps for determining the focus specifically include:

[0065] Place the workpiece to be welded on the welding processing plane;

[0066] Make solder joints Z +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 、Z +3 、Z -3 、Z

[0067] 、Z +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 on the workpiece to be welded. Among them, the focus position of the solder joint Z0 is 0, and the focus gradually shifts upward from the solder joint Z0 to Z

[0068] such asFigure 1 As shown, make seven solder joints of Z +3 , Z +2 , Z +1 , Z0, Z -1 , Z -2 , Z -3 on the workpiece to be welded. The laser focus position of solder joint Z0 is 0, and the laser focus position of solder joint Z +1 is +0.1mm, the laser focus position of solder joint Z +2 is +0.2mm, and the laser focus position of solder joint Z +3 is 0 + 0.3mm; the laser focus position of solder joint Z -1 is -0.1mm, the laser focus position of solder joint Z -2 is -0.2mm, and the laser focus position of solder joint Z -3 is -0.3mm. Determine the focus position used during welding by making seven solder joints with different foci on the welded part.

[0069] In other embodiments, the number of solder joints made when determining the focus can also be adjusted as needed. For example Figure 1 7 solder joints are used in , and 5, 9 or other numbers can also be used in other embodiments. The focus of each point can also be adjusted as needed, which will not be elaborated here.

[0070] The laser welding method for brass workpieces and phosphor bronze workpieces in the embodiments of the present application further includes the steps of:

[0071] Dip a lint-free cloth in alcohol to wipe the surface dirt and debris of the upper brass workpiece and the lower phosphor bronze workpiece respectively, clean them, and dry for 5 - 6 minutes;

[0072] Assemble the upper brass workpiece and the lower phosphor bronze workpiece into a workpiece to be welded according to the welding position, lock them, and make the fitting gap between the brass workpiece and the phosphor bronze workpiece less than 1 / 10 of the thickness of the upper material;

[0073] Perform preliminary positioning, and place the workpiece to be welded at the preview position indicated by the laser red light;

[0074] Perform secondary positioning, trajectory teaching, aiming, determine the welding position, set the light output parameters, and perform laser welding;

[0075] Preliminarily observe the appearance cracks and spatter of the weld under a microscope;

[0076] Grind and polish the outer surface of the weld, corrode it with a solution, measure the penetration depth, width, and reinforcement height of the weld; observe and analyze the defects such as transverse and longitudinal weld cross-section cracks and pores of the weld under a metallurgical microscope for the second time.

[0077] Obviously, the above embodiments of the present application are merely examples for clearly illustrating the present application, rather than limitations on the implementation manners of the present application. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present application. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present application shall be included within the protection scope of the claims of the present application.

Claims

1. A laser welding method for brass workpieces and phosphor bronze workpieces, characterized in that, Including the steps: Assemble the brass workpiece and the phosphor bronze workpiece onto the welding jig; Weld the brass workpiece and the phosphor bronze workpiece using a nanosecond green laser. The wavelength of the nanosecond green laser is 510 - 535 nm, and the pulse width is 195 - 1050 ns; the average output power of the laser is 30 - 55 W, the welding speed is 45 - 85 mm / s, and the laser focus position is 0 to -0.3 mm; The thickness of the brass workpiece is 0.08 - 0.12 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.3 mm; or, the thickness of the brass workpiece is 0.12 - 0.14 mm, and the phosphor bronze workpiece is 0.2 - 0.4 mm; or, the thickness of the brass workpiece is 0.14 - 0.16 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.5 mm; During welding, the brass workpiece is on the upper layer and the phosphor bronze workpiece is on the lower layer, and the assembly gap between the brass workpiece and the phosphor bronze workpiece is less than 1 / 10 of the thickness of the brass workpiece on the upper layer; Using the above laser wavelength and laser processing parameters, the single-pulse energy during processing is less than or equal to 450 uJ.

2. The laser welding method for brass workpieces and phosphor bronze workpieces according to claim 1, characterized in that, The thickness of the brass workpiece is 0.08 - 0.12 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.3 mm; The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 200 KHz, and the pulse width is 1000 ns; the laser welding parameters are: spiral dots, the filling pitch is 0.02 - 0.03 mm, or, rectangular frame dots, the filling pitch is 0.015 - 0.035 mm; the solder joint diameter is 0.35 - 0.45 mm; the average output power of the laser is 35 - 38 W, the welding speed is 60 - 80 mm / s, and the laser focus position is 0 to -0.3 mm.

3. The laser welding method for brass workpieces and phosphor bronze workpieces according to claim 1, characterized in that, The thickness of the brass workpiece is 0.12 - 0.14 mm, and the phosphor bronze workpiece is 0.2 - 0.4 mm; The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 250 - 350 KHz, and the pulse width is 500 ns; the laser welding parameters are: spiral dots, the filling pitch is 0.01 - 0.025 mm, or, rectangular frame dots, the filling pitch is 0.015 - 0.035 mm; the solder joint diameter is 0.35 - 0.45 mm; the average output power of the laser is 37 - 42 W, the welding speed is 50 - 70 mm / s, and the laser focus position is 0 to -0.3 mm.

4. The laser welding method for brass workpieces and phosphor bronze workpieces according to claim 1, characterized in that, The thickness of the brass workpiece is 0.14 - 0.16 mm, and the thickness of the phosphor bronze workpiece is 0.1 - 0.5 mm; The laser wavelength is 532 nm; the laser waveform is a square wave, the laser repetition frequency is 1000 KHz, and the pulse width is 200 ns; the laser welding parameters are: spiral dots, the filling pitch is 0.01 - 0.025 mm, or, rectangular frame dots, the filling pitch is 0.01 - 0.03 mm; the solder joint diameter is 0.35 - 0.45 mm; the average output power of the laser is 40 - 50 W, the welding speed is 50 - 80 mm / s, and the laser focus position is 0 to -0.3 mm.

5. The laser welding method for brass workpieces and phosphor bronze workpieces according to claim 1, characterized in that, The wavelength of the nanosecond green laser is 532 nm.

6. The laser welding method for brass workpieces and phosphor bronze workpieces according to any one of claims 1 to 5, characterized in that, Also including the steps: Determine the focus: Place the workpiece to be welded on the welding processing plane, and use a laser to make multiple weld spots with different foci on the workpiece to be welded. By detecting the appearance and quality of the multiple weld spots, determine the focus position selected during welding.

7. The laser welding method for brass workpieces and phosphor bronze workpieces according to claim 6, characterized in that, The steps for determining the focus specifically include: Place the workpiece to be welded on the welding processing plane; Make Z on the workpiece to be welded +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 Seven welding points, where the focus position of welding point Z0 is 0, and from welding point Z0 to Z +3 the focus gradually shifts upward, and from welding point Z0 to Z -3 the focus gradually shifts downward; By detecting the solder joints Z +3 、Z +2 、Z +1 、Z0、Z -1 、Z -2 、Z -3 's appearance and quality, determine the focal position selected during welding.

8. The laser welding method for brass workpieces and phosphor bronze workpieces according to any one of claims 1 to 5, characterized in that, The welding strength between the brass workpiece and the phosphor bronze workpiece is: the welding strength of 3 weld spots is greater than or equal to 80 N, and the welding strength of 15 weld spots is greater than or equal to 400 N.

9. The laser welding method for brass workpieces and phosphor bronze workpieces according to any one of claims 1 to 5, characterized in that, The brass material model used for the brass workpiece is C2600, and the phosphor bronze material model used for the phosphor bronze workpiece is C5191.

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