Laser welding method for connecting beryllium special-shaped workpieces by using aluminum alloy as filler metal
Patent Information
- Application Number
- CN202411919281.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-03-18
AI Technical Summary
During beryllium welding, deformation, uneven stress, brittle compound generation and pore defects are easily caused, resulting in reduced weld strength and unsightly surface quality.
Aluminum alloy is used as the filler metal, and impurities and gases on the surface of the beryllium hemispherical shell are removed through pre-washing, pickling, alkaline washing, rinsing and vacuum degassing steps. Combined with laser welding technology, the matching phase diagram of the aluminum alloy filler and the beryllium hemispherical shell is used to avoid the formation of brittle secondary phases.
It significantly improves the strength and surface quality of beryllium welds, reduces the problems of deformation and uneven stress distribution during welding, avoids the formation of brittle compounds, and improves the dimensional accuracy and aesthetics of welding.
Smart Images
Figure CN119634968A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of beryllium metal welding methods, and in particular to a laser welding method for connecting beryllium special-shaped workpieces by using aluminum alloy as filler metal. Background Art
[0002] As an emerging metal material, beryllium is increasingly valued for its high elastic modulus, high specific strength, low linear expansion coefficient, and high specific heat capacity. Beryllium is an indispensable and valuable material in atomic energy, rockets, missiles, aviation, aerospace, and metallurgical industries. Beryllium will cause deformation and uneven stress distribution in different directions during welding; in addition, beryllium easily absorbs oxygen, nitrogen and other elements in the environment during welding and reacts to form brittle compounds (such as BeO, Be 2 C, etc.), which results in a decrease in the strength of the beryllium weld, and even under protective conditions, it is easy to produce porosity defects. At present, adding dissimilar filler metals between beryllium and beryllium to improve the performance of beryllium welds has become a trend in the study of beryllium fusion welding. The traditional beryllium welding process does not effectively pretreat the material before welding, resulting in a large number of impurities in the area to be welded. In addition, during welding, affected by the temperature of the arc starting and arc ending stages, the weld is prone to defects such as humps and arc pits, resulting in an unsightly weld surface quality. Summary of the invention
[0003] In order to overcome the shortcomings of the prior art, the present invention provides a laser welding method for connecting beryllium special-shaped workpieces by using aluminum alloy as filler metal.
[0004] The technical solution of the present invention is as follows: A laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal comprises the following steps:
[0005] Step 1, pre-wash
[0006] The aluminum alloy filler was polished to remove the surface oxide layer. The beryllium hemispherical shell a and the beryllium hemispherical shell b were immersed in anhydrous ethanol and acetone for ultrasonic treatment respectively, and then dried with a dust-free cloth.
[0007] Step 2: pickling, alkali washing, rinsing
[0008] The beryllium hemispherical shell a and the beryllium hemispherical shell b are immersed in an acid solution, and then rinsed in deionized water; the beryllium hemispherical shell a and the beryllium hemispherical shell b are then immersed in an alkaline solution, rinsed again with deionized water, and then dried and transferred for standby use.
[0009] Step 3, vacuum degassing
[0010] The beryllium hemispherical shell a, the beryllium hemispherical shell b and the aluminum alloy filler are transferred into a vacuum furnace, and the vacuum furnace is evacuated and then heated to remove the gas adsorbed on the surface of the beryllium hemispherical shell.
[0011] Step 4: Workpiece clamping
[0012] Take out beryllium hemispherical shell a and beryllium hemispherical shell b, clamp the aluminum alloy filler in between, and use the tail top device to fix and clamp the beryllium hemispherical shell and the aluminum alloy filler.
[0013] Step 5: Preheating the workpiece
[0014] The weld at the connection between the beryllium hemispherical shell and the filler is preheated in the glove box.
[0015] Step 6, Laser Welding
[0016] Turn on the laser and perform laser welding on the weld.
[0017] Step 7. Cooling
[0018] The welded workpiece is cooled to room temperature along with the glove box temperature.
[0019] The radial thickness of the beryllium hemispherical shell a and the beryllium hemispherical shell b is less than 3 mm, the outer diameter is 150-300 mm, and L-shaped cuts are respectively arranged at both ends of the beryllium hemispherical shell.
[0020] The aluminum alloy filler is Al-Si alloy or Al-Ag alloy, with an Al content of 70-80%. The aluminum alloy filler is stepped, matching the L-shaped cutout of the beryllium hemispherical shell, and has a thickness of 0.1-0.5 mm.
[0021] In the step 1, the beryllium hemispherical shell a and the beryllium hemispherical shell b are ultrasonically cleaned in anhydrous ethanol and acetone at a frequency of 100 to 150 Hz, and are immersed in ultrasonic treatment for 3 to 5 minutes respectively.
[0022] In step 2, the cleaning solution acid solution is 8-10% HNO 3 +0.5~1% HF aqueous solution, pH value is 1~2, immerse in it for 3min; alkali solution is 3~5% Na 2 CO 3 The sample was immersed in an aqueous solution with a pH value of 11-12 for 5 minutes; the two deionized water rinses were each for 5 minutes.
[0023] In the step 3, the vacuum furnace is evacuated to 4 Pa and then heated at a heating temperature of 350° C. for a holding time of 5 hours.
[0024] In the step 5, the preheating method in the glove box is to preheat the weld by blowing heated argon gas, the preheating temperature is 100-300° C., the preheating time is 10-30 minutes, and the preheating argon gas flow rate is 1-10 L / min.
[0025] In the step 3, after the beryllium hemispherical shell removes the gas adsorbed on the surface, the water and oxygen content is required to be ≤3ppmV, and the oxygen content is required to be ≤5ppm; in the step 5, the water and oxygen content of the glove box is required to be ≤3ppmV, and the oxygen content is ≤5ppm.
[0026] In step 6, the power control of the laser during welding is as follows: in the arc starting stage within the range of 0 to 0.5s, the laser output power is 1500 to 1800W, and the welding speed is 5 to 8mm / s; in the formal welding stage, the laser output power is 1300 to 1600W, and the welding speed is 8 to 10mm / s; in the arc closing stage, the laser output power is 1000 to 1300W, and the welding speed is 8 to 10mm / s.
[0027] Before step 3, the method further includes: replacing the atmosphere of the vacuum furnace with argon or helium.
[0028] The present invention provides a laser welding method for connecting beryllium special-shaped workpieces by using aluminum alloy as filler metal, and the remarkable effects are: through pre-washing, pickling, alkali washing and rinsing operations, the gas adsorbed on the welding surface of the beryllium hemispherical shell is removed by using chemical solution, and an inert atmosphere environment and extremely low water and oxygen content are maintained throughout the subsequent processing process; vacuum degassing operation further reduces gas impurities adsorbed by the material of the welding part; the beryllium hemispherical shell is preheated before laser welding, reducing the internal stress of the material in the welding area and the generation of cracks caused by residual stress after welding; after the two beryllium hemispherical shells are matched, a tail top device is used It is fixed on a rotating workbench to ensure dimensional accuracy after welding; the aluminum alloy filler is Al-Si alloy or Al-Ag alloy. According to the binary alloy phase diagram, Be-Al, Be-Si, and Be-Ag can have no other secondary phases within the temperature range, eliminating the possibility of brittle secondary phases in the weld; the matching relationship between the laser output power and the welding speed in the arc starting stage, welding stage, and arc ending stage proposed in the present invention can be flexibly selected according to the thickness of the workpiece and the actual conditions of the laser welding machine, which can effectively avoid excessive temperature differences in the arc starting and arc ending stages and ensure welding quality. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.
[0030] Figure 1 This is the assembly drawing of the beryllium hemispherical shell stop;
[0031] Figure 2 This is an enlarged view of the stop portion of the beryllium hemispherical shell;
[0032] Figure numerals: 1 - beryllium hemispherical shell a; 2 - beryllium hemispherical shell b; 3 - aluminum alloy filler. DETAILED DESCRIPTION
[0033] In order to make those skilled in the art better understand the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, not all. Based on the embodiments recorded in the present application, all other embodiments obtained by those skilled in the art without paying creative work are within the scope of protection of the present application.
[0034] The following describes in detail a laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal provided by the present application in conjunction with several specific embodiments.
[0035] Example 1
[0036] In the laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal in this embodiment, the beryllium special-shaped workpieces, namely the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2, refer to Figure 1 The radial thickness of the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 is 2.8 mm, the outer diameter is 300 mm, and L-shaped cuts are respectively provided at both ends of the beryllium hemispherical shell;
[0037] Aluminum alloy filler 3 see Figure 2 The selected filler is Al-Si alloy with an Al content of 88%. The thickness of the aluminum alloy filler 3 is 0.5 mm and is stepped, matching the L-shaped cutout of the beryllium hemispherical shell.
[0038] Optionally, the aluminum alloy filler 3 may also be an Al—Ag alloy.
[0039] A laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal in this embodiment includes the following steps:
[0040] Step 1: Pre-wash
[0041] The surface oxide layer of the aluminum alloy filler 3 was removed by grinding with 2000# sandpaper; the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 were immersed in anhydrous ethanol and acetone for ultrasonic treatment, the ultrasonic cleaning frequency was 150 Hz, and they were immersed in ultrasonic treatment for 3 minutes respectively, and then dried with a dust-free cloth.
[0042] Step 2: Pickling, rinsing, alkali washing
[0043] Place the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 in an acid solution (the cleaning solution is 10% HNO 3 +0.5%HF+89.5%H 2O aqueous solution) for 3 minutes, and then rinsed in deionized water for 5 minutes (pH value close to 7). Visually, the welding surface of beryllium hemispherical shell a1 and beryllium hemispherical shell b2 showed a uniform steel gray color without obvious spots. 2 CO 3 +96%H 2 The samples were immersed in a deionized water solution of 5% acetone for 5 min, then rinsed in deionized water for 5 min, wiped dry with a dust-free cloth, visually inspected, and transferred to fresh acetone for use.
[0044] Step 3: Vacuum Degassing
[0045] Use argon or helium to replace the atmosphere in the vacuum furnace; transfer the two beryllium hemispherical shells and the aluminum alloy filler 3 into the vacuum furnace, evacuate the vacuum furnace to 4Pa and then heat it at 350°C for 5h; after removing the gas adsorbed on the surface of the beryllium hemispherical shell, the water oxygen content is required to be ≤3ppmV, and the oxygen content is required to be ≤5ppm.
[0046] Step 4: Workpiece clamping
[0047] Take out the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2, quickly transfer them to the workbench of the special atmosphere replacement glove box, clamp the aluminum alloy filler 3 between the two beryllium hemispherical shells, use the tail top device on the workbench to assemble and fix the hemispherical shell and the filler to the workbench, then use the tail top device to adjust the ring weld in the vertical plane, clamp the tail top device to achieve the clamping of the spherical shell.
[0048] Step 5: Preheating the workpiece
[0049] The spherical shell ring weld is preheated in the glove box by means of heating argon gas blowing the ring weld, the preheating temperature is 100-300°C, the preheating time is 10-30min, and the preheating argon gas flow rate is 1-10L / min, until the water oxygen content in the glove box is less than 3ppm.
[0050] Step 6: Laser Welding
[0051] Turn on the laser, control a certain laser output power and welding speed, and perform laser welding on the ring weld; the laser power control during welding is as follows: in the arc starting stage, the laser output power is 1800W within the range of 0 to 0.5s, and the welding speed is 8mm / s; in the formal welding stage, the laser output power is 1600W, and the welding speed is 10mm / s; in the arc closing stage, the laser output power is 1300W, and the welding speed is 10mm / s.
[0052] Step 7: Cooling
[0053] The welded workpiece is cooled to room temperature along with the glove box temperature.
[0054] Example 2
[0055] In the laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal in this embodiment, the beryllium special-shaped workpieces, namely the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2, refer to Figure 1 The radial thickness of the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 is 2.1 mm, the outer diameter is 225 mm, and L-shaped cuts are provided at both ends of the beryllium hemispherical shell;
[0056] Aluminum alloy filler 3 see Figure 2 The selected filler is Al-Si alloy with an Al content of 70%. The thickness of the aluminum alloy filler 3 is 0.3 mm and is stepped, matching the L-shaped cutout of the beryllium hemispherical shell.
[0057] Optionally, the aluminum alloy filler 3 may also be an Al—Ag alloy.
[0058] This embodiment is a laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal, referring to Example 1, and the difference from Example 1 is that:
[0059] In the pre-cleaning step, the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 were ultrasonically cleaned in anhydrous ethanol and acetone at a frequency of 125 Hz and immersed in ultrasonic treatment for 4 minutes respectively.
[0060] In the acid washing, alkaline washing and rinsing steps, in the acid solution (9% HNO 3 +0.9%HF+90.1%H 2 O aqueous solution) for 3 min; then rinsed in deionized water (pH close to 7) for 5 min; then the two beryllium hemispherical shells were immersed in an alkaline solution (3% Na 2 CO 3 +97%H 2 O aqueous solution) for 5 min and rinsed again in deionized water for 5 min.
[0061] During the laser welding process, the power of the laser is controlled as follows: in the arc starting stage, the laser output power is 1700W and the welding speed is 7mm / s in the range of 0 to 0.5s; in the formal welding stage, the laser output power is 1500W and the welding speed is 9mm / s; in the arc closing stage, the laser output power is 1100W and the welding speed is 9mm / s.
[0062] Example 3
[0063] In the laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal in this embodiment, the beryllium special-shaped workpieces, namely the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2, refer to Figure 1 The radial thickness of the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 is 1.4 mm, the outer diameter is 150 mm, and L-shaped cuts are respectively provided at both ends of the beryllium hemispherical shell;
[0064] Aluminum alloy filler 3 see Figure 2 The selected filler is Al-Si alloy with an Al content of 80%. The thickness of the aluminum alloy filler 3 is 0.1 mm and is stepped, matching the L-shaped cutout of the beryllium hemispherical shell.
[0065] Optionally, the aluminum alloy filler 3 may also be an Al—Ag alloy.
[0066] This embodiment is a laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal, referring to Example 1, and the difference from Example 1 is that:
[0067] In the pre-cleaning step, the beryllium hemispherical shell a1 and the beryllium hemispherical shell b2 were ultrasonically cleaned in anhydrous ethanol and acetone at a frequency of 100 Hz and immersed in ultrasonic treatment for 5 minutes respectively.
[0068] In the acid washing, alkaline washing and rinsing steps, the two beryllium hemispherical shells were immersed in an acid solution (8% HNO3+1% HF+91% H2O aqueous solution) for 3 minutes; then rinsed in deionized water (pH value close to 7) for 5 minutes; then the two beryllium hemispherical shells were immersed in an alkaline solution (5% Na2CO3+95% H2O aqueous solution) for 5 minutes, and rinsed again in deionized water for 5 minutes.
[0069] During the laser welding process, the power of the laser is controlled as follows: in the arc starting stage, the laser output power is 1500W within the range of 0 to 0.5s, and the welding speed is 5mm / s; in the formal welding stage, the laser output power is 1300W, and the welding speed is 8mm / s; in the arc closing stage, the laser output power is 1000W, and the welding speed is 8mm / s.
[0070] The above description is only a preferred embodiment of this patent and is not intended to limit this patent. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this patent should be included in the scope of protection of this patent.
[0071] It should be noted that, for the convenience of description, the aforementioned method embodiments are all described as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.
[0072] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0073] The preferred embodiments of the present application disclosed above are only used to help explain the present application. The optional embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the present application. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can understand and use the present application well.
Claims
1. A laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal, characterized in that: The following steps are involved: Step 1, pre-wash: The aluminum alloy filler (3) is polished to remove the surface oxide layer, and the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2) are immersed in anhydrous ethanol and acetone for ultrasonic treatment in turn, and then dried with a dust-free cloth; Step 2, pickling, alkali washing, rinsing: Immerse the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2) in an acid solution, and then rinse them in deionized water; then immerse the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2) in an alkaline solution, rinse them again with deionized water, and transfer them for later use after drying; Step 3, vacuum degassing: The beryllium hemispherical shell a (1), the beryllium hemispherical shell b (2) and the aluminum alloy filler (3) are placed in a vacuum furnace, and the vacuum furnace is evacuated and then heated to remove the gas adsorbed on the surface of the beryllium hemispherical shell; Step 4, workpiece clamping: Take out the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2), clamp an aluminum alloy filler (3) in between, and use a tail top device to fix and clamp the beryllium hemispherical shell and the aluminum alloy filler (3); Step 5, workpiece preheating: Preheating the weld at the connection between the beryllium hemispherical shell and the filler in a glove box; Step 6, Laser Welding: Turn on the laser to perform laser welding on the weld; Step 7, Cooling: The welded workpiece is cooled to room temperature along with the glove box temperature.
2. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: The radial thickness of the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2) is less than 3 mm, the outer diameter is 150-300 mm, and L-shaped cuts are respectively arranged at both ends of the beryllium hemispherical shell.
3. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: The aluminum alloy filler (3) is an Al-Si alloy or an Al-Ag alloy, with an Al content of 70-80%. The aluminum alloy filler (3) is in a stepped shape, matching the L-shaped cutout of the beryllium hemispherical shell, and has a thickness of 0.1-0.5 mm.
4. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In the step 1, the beryllium hemispherical shell a (1) and the beryllium hemispherical shell b (2) are ultrasonically cleaned in anhydrous ethanol and acetone at a frequency of 100 to 150 Hz, and are immersed in ultrasonic treatment for 3 to 5 minutes respectively.
5. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In step 2, the cleaning solution acid solution is an aqueous solution of 8-10% HNO3 + 0.5-1% HF, with a pH value of 1-2, and the mixture is immersed in it for 3 minutes; The alkaline solution is a 3-5% Na2CO3 aqueous solution with a pH value of 11-12, and the samples are immersed in the solution for 5 minutes; the duration of the two deionized water rinses is 5 minutes each.
6. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In the step 3, the vacuum furnace is evacuated to 4 Pa and then heated at a heating temperature of 350° C. for a holding time of 5 hours.
7. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In the step 5, the preheating method in the glove box is to preheat the weld by blowing heated argon gas, the preheating temperature is 100-300° C., the preheating time is 10-30 minutes, and the preheating argon gas flow rate is 1-10 L / min.
8. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In the step 3, after the beryllium hemispherical shell removes the gas adsorbed on the surface, the water and oxygen content is required to be ≤3ppmV, and the oxygen content is required to be ≤5ppm; in the step 5, the water and oxygen content of the glove box is required to be ≤3ppmV, and the oxygen content is ≤5ppm.
9. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: In step 6, the power control of the laser during welding is as follows: in the arc starting stage within the range of 0 to 0.5s, the laser output power is 1500 to 1800W, and the welding speed is 5 to 8mm / s; in the formal welding stage, the laser output power is 1300 to 1600W, and the welding speed is 8 to 10mm / s; in the arc closing stage, the laser output power is 1000 to 1300W, and the welding speed is 8 to 10mm / s.
10. The laser welding method for connecting beryllium special-shaped workpieces using aluminum alloy as filler metal according to claim 1, characterized in that: Before step 3, the method further includes: replacing the atmosphere of the vacuum furnace with argon or helium.