Electron beam welding method for high-entropy alloy and stainless steel metal plate

Abstract

The invention provides an electron beam welding method for a high-entropy alloy and a stainless steel metal plate, belongs to the technical field of vacuum welding, and solves the problems of stress concentration, thermal retention time period and easy crack generation of a welding seam in the welding process of the high-entropy alloy and stainless steel, and the electron beam welding method comprises the following steps: step 1, determining a to-be-welded interface of the high-entropy alloy and the stainless steel metal plate; step 2, assembling a workpiece; 3, vacuum welding is conducted; and 4, welding is completed, heat preservation is conducted, and the welded workpiece is taken out. The method is simple in process and easy to implement, compared with adjustment and control by adding a middle metal layer or a complex welding process, the arc-shaped welding seam design is easy to process and implement, and the method is suitable for large-scale industrial production and has high practicability and popularization value.

Description

Technical Field

[0001] The invention relates to an electron beam welding method for a high entropy alloy and a stainless steel metal plate, belonging to the technical field of vacuum welding. Background Art

[0002] In modern manufacturing, electron beam welding technology has been widely used in the connection of various metal materials. With the emergence of high entropy alloys and their application in engineering, the research on dissimilar metal welding technology has become an important emerging research field. High entropy alloys are ideal structural materials due to their excellent mechanical properties and corrosion resistance, but they have high production costs and long production cycles. Therefore, by exploring the structural design of welded joints between high entropy alloys and other metals, product costs can be further reduced, production efficiency can be improved, and product competitiveness can be enhanced. It has important application potential in aerospace, automotive, and energy fields.

[0003] High entropy alloys have attracted much attention due to their excellent comprehensive properties, especially the nanotwins and work hardening effects produced during the deformation process, which make them exhibit excellent mechanical properties at both room temperature and low temperature, especially in terms of hydrogen embrittlement resistance and fracture toughness. They are suitable for parts that require extreme low temperature resistance. However, due to its complex preparation process and high cost, its wide application is limited. In comparison, stainless steel has good corrosion resistance and mechanical properties, and has been widely used in chemical, aviation, marine and other fields. It has a relatively economical price and also has good low temperature performance. Combining high entropy alloys with stainless steel to make structural parts, stainless steel has higher cost-effectiveness, while high entropy alloys can provide better performance and environmental corrosion resistance in key parts, achieving performance optimization while reducing costs, and further promoting the application of high entropy alloys in industrial applications.

[0004] There are obvious differences in thermophysical properties and material composition between high entropy alloys and stainless steel, especially in thermal expansion coefficient and specific heat capacity, which makes stress concentration easy to occur during welding. The difference in composition may also cause poor metallurgical compatibility. Therefore, during electron beam welding, under the combined effect of the above factors, stress concentration may occur in the welding area, which in turn leads to the formation of cracks and reduces the mechanical properties and reliability of the welded joint. In addition, the cooling rate of electron beam welding is relatively fast, while high entropy alloys are more sensitive to the cooling rate, and rapid cooling may cause welding cracks. Therefore, the cooling process must be controlled to appropriately extend the high temperature residence time of the weld to suppress welding stress and reduce the occurrence of cracks. Slow cooling is generally achieved by reducing the welding speed. To improve metallurgical compatibility, methods such as adding metal layers are usually used, which not only requires a lot of process exploration and test materials, but also makes the process complicated and less practical. To this end, the present invention proposes a method for electron beam welding of high entropy alloys and stainless steel metal plates. The arc structure is adopted to effectively alleviate the problem of stress concentration, increase the high-temperature residence time of the weld, reduce the cooling rate, and improve the weld performance. At the same time, the mechanically stable structure can also improve the weld reliability. Summary of the invention

[0005] The present invention aims to solve the problems of stress concentration, thermal dwell time period and easy cracking of welds during welding of high entropy alloy and stainless steel, and further proposes a method for electron beam welding of high entropy alloy and stainless steel metal plates, which specifically includes:

[0006] Step 1: prepare high entropy alloy and stainless steel metal plates of the same size, and process a continuous arc-shaped welding interface on the high entropy alloy and stainless steel metal plates;

[0007] Step 2: Grind the interface to be welded with sandpaper, perform ultrasonic cleaning on the polished high entropy alloy and stainless steel metal plates, wipe the ultrasonically cleaned high entropy alloy and stainless steel metal plates with an organic solvent, and blow dry immediately after wiping;

[0008] Step 3: Align the wiped high entropy alloy and stainless steel metal plate welding machine surfaces for assembly, clamp and fix the assembled high entropy alloy and stainless steel metal plates on the welding fixture and place them in the vacuum chamber of the electron beam welder, start the multi-stage vacuum system to evacuate until the pressure in the vacuum chamber of the electron beam welder reaches the preset value;

[0009] Step 4: Turn on the electron gun high voltage system, adjust the focusing current, locate the focusing position to the flat surface, select the corresponding welding parameters, control the electron beam to weld the high entropy alloy and the stainless steel metal plate along the arc weld, and keep the temperature in the vacuum chamber after welding;

[0010] Step 5: After the insulation is completed, take out the workpiece and complete the electron beam welding of the high entropy alloy and the stainless steel.

[0011] Preferably, in step 1, each adjacent semicircular arc interface between the high entropy alloy and the stainless steel metal plate is tangent, and the arc-shaped interface to be welded between the high entropy alloy and the stainless steel metal plate has the same size.

[0012] Preferably, the mesh size of the sandpaper used for polishing in step 2 is 1000-2000 mesh, the ultrasonic cleaning frequency is 20 kHz, the cleaning time is 5 minutes, and the organic solvent is petroleum ether.

[0013] Preferably, the preset pressure value in step 3 is 5×10 -2 Pa.

[0014] Preferably, in step 4, the welding voltage during the welding process is 60 kV, the welding current is 5-20 mA, and the insulation time is 15 min.

[0015] The beneficial effects of the present invention are:

[0016] (1) The present invention is suitable for welding high-entropy alloys and stainless steel with a thickness of 2-8 mm. By adopting an arc weld design, the arc weld significantly increases the contact area of ​​the joint interface compared to the straight weld, making the welding part more firm and improving the strength and stability of the welded joint.

[0017] (2) The full curved structure of the arc weld helps to disperse the stress generated during the welding process. Compared with traditional straight welds, the arc weld can naturally guide the stress distribution, thereby avoiding the stress concentration problem caused by the difference in the thermal physical properties of dissimilar metals and reducing the risk of cracks.

[0018] (3) The arc structure of the present invention forms a mechanical stabilization effect in the weld, improving the crack resistance and service reliability of the weld. Even if cracks occur locally in the joint, the curved weld can limit the expansion of the crack and enhance the crack resistance of the weld. In this way, even if a small defect occurs, the joint can still maintain the basic connection function, increasing safety and reliability.

[0019] (4) The process of the present invention is simple and easy to implement. Compared with the process of adding an intermediate metal layer or complex welding process control, the arc weld design of the present invention is easy to process and implement, suitable for large-scale industrial production, and has high practicality and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a process for electron beam welding of a high entropy alloy and a stainless steel metal plate provided by the present invention;

[0021] Figure 2 A schematic diagram of the assembly process of the high entropy alloy and stainless steel during electron beam welding provided by the present invention;

[0022] Figure 3 The specific dimension diagram of the arc weld of the high entropy alloy and stainless steel provided by the present invention with the dimension of 150mm×40mm×2mm;

[0023] Figure 4 The specific dimension diagram of the arc weld of the high entropy alloy and stainless steel provided by the present invention is 300mm×80mm×4mm;

[0024] Figure 5 The specific dimension diagram of the arc weld between the high entropy alloy and stainless steel provided by the present invention is 600mm×160mm×6mm. DETAILED DESCRIPTION

[0025] Specific implementation method 1: Combination Figure 1-3 To illustrate this embodiment, Figure 1 As shown, the steps of a high entropy alloy and stainless steel metal plate electron beam welding method described in this embodiment include:

[0026] S1: Determine the welding interface between the high entropy alloy and the stainless steel metal plate;

[0027] In this embodiment, a high entropy alloy and stainless steel metal plate with a size of 150 mm × 40 mm × 2 mm is used. Figure 3 As shown, a semi-arc interface with a long axis of 10 mm and a short axis of 5 mm is processed at the interface to be welded. Each adjacent semi-arc interface between the high entropy alloy and the stainless steel metal plates is tangent. The sizes of the arc interfaces of the high entropy alloy and the stainless steel metal plates are exactly the same. The processed butt surfaces of the two plates should match each other and be smooth and flat. For plates of different sizes, the size of the arc interface can be adjusted accordingly.

[0028] This embodiment adopts an arc weld design. Compared with a straight weld, the arc weld significantly increases the contact area of ​​the joint interface, makes the welding part more firm, and improves the strength and stability of the welded joint.

[0029] S2: Workpiece assembly;

[0030] S201: Use 1000-2000# sandpaper to polish the interface to be welded to remove pollutants such as oxides and rust until the interface is bright.

[0031] S202: ultrasonically clean the polished high entropy alloy and the stainless steel plate to be welded at a frequency of 20 kHz for 5 minutes to remove pollutants such as oily water stains, and then wipe the interface to be welded with petroleum ether or other organic solvents, and blow dry immediately after wiping;

[0032] S203: Figure 2 As shown, the wiped high entropy alloy and stainless steel metal plates are assembled to ensure that the interfaces to be welded of the metal plates are aligned and overlapped.

[0033] S3: Vacuum welding;

[0034] S301: Clamp and fix the assembled high entropy alloy and stainless steel metal plate on the welding fixture, place the fixture and the metal plate into the vacuum chamber of the electron beam welding machine after fixation, and start the multi-stage vacuum system to evacuate;

[0035] S302: When the vacuum degree of the vacuum chamber reaches 5×10 -2 When 0.05 Pa, turn on the electron gun high voltage system, adjust the focusing current, locate the focusing position to the flat surface, select appropriate welding parameters, and control the electron beam to weld the high entropy alloy and stainless steel along the arc weld.

[0036] In this embodiment, the full curved structure of the arc weld helps to disperse the stress generated during the welding process. Compared with the traditional straight weld, the arc weld can naturally guide the stress distribution, thereby avoiding the stress concentration problem caused by the difference in the thermophysical properties of dissimilar metals and reducing the risk of cracks. The arc structure forms a mechanical stability effect in the weld, improving the crack resistance and service reliability of the weld. Even if cracks occur locally in the joint, the curved weld can limit the expansion of the crack and enhance the crack resistance of the weld. In this way, even if a small defect occurs, the joint can still maintain the basic connection function, increasing safety and reliability.

[0037] S4: Finish welding and keep warm, then take out the welded workpiece;

[0038] After welding is completed, keep the workpiece in the vacuum chamber for 10 to 20 minutes and then take it out.

[0039] Specific implementation method 2: Combination Figure 1 , Figure 2 and Figure 4 This embodiment is described as follows. Figure 1 As shown, the steps of a high entropy alloy and stainless steel metal plate electron beam welding method described in this embodiment include:

[0040] S1: Determine the welding interface between the high entropy alloy and the stainless steel metal plate;

[0041] In this embodiment, high entropy alloy and stainless steel metal plates with a size of 300 mm×80 mm×4 mm are prepared, such as Figure 4 As shown, a semi-arc interface with a long axis of 40 mm and a short axis of 20 mm is processed on the interface to be welded, each adjacent semi-arc interface is tangent to each other, the arc interface sizes of the two plates are exactly the same, and the processed butt surfaces of the two plates match each other and are smooth and flat.

[0042] S2: Workpiece assembly;

[0043] S201: Use 1000-2000# sandpaper to polish the interface to be welded to remove pollutants such as oxides and rust until the interface is bright.

[0044] S202: ultrasonically clean the polished high entropy alloy and the stainless steel plate to be welded at a frequency of 20 kHz for 5 minutes to remove pollutants such as oily water stains, and then wipe the interface to be welded with petroleum ether or other organic solvents, and blow dry immediately after wiping;

[0045] S203: Figure 2 As shown, the wiped high entropy alloy and stainless steel metal plates are assembled to ensure that the interfaces to be welded of the metal plates are aligned and overlapped.

[0046] S3: Vacuum welding;

[0047] S301: Clamp and fix the assembled high entropy alloy and stainless steel metal plate on the welding fixture, place the fixture and the metal plate into the vacuum chamber of the electron beam welding machine after fixation, and start the multi-stage vacuum system to evacuate;

[0048] S302: When the vacuum degree of the vacuum chamber reaches 5×10 -2 Pa, turn on the electron gun high voltage system, adjust the focusing current, locate the focusing position to the flat surface, set the welding voltage to 60 kV, and the welding current to 5-20 mA to ensure that the weld is fully melted without obvious concave or convex, and control the electron beam to weld the high entropy alloy and stainless steel along the arc weld.

[0049] S4: Finish welding and keep warm, then take out the welded workpiece;

[0050] After welding is completed, keep the workpiece in the vacuum chamber for 15 minutes and then take it out.

[0051] Specific implementation method three: Combination Figure 1 , Figure 2 and Figure 5 This embodiment is described as follows. Figure 1 As shown, the steps of a high entropy alloy and stainless steel metal plate electron beam welding method described in this embodiment include:

[0052] S1: Determine the welding interface between the high entropy alloy and the stainless steel metal plate;

[0053] In this embodiment, high entropy alloy and stainless steel metal plates with a size of 600 mm×160 mm×6 mm are prepared, such as Figure 5 As shown, a semi-arc interface with a long axis of 40 mm and a short axis of 20 mm is processed on the interface to be welded, each adjacent semi-arc interface is tangent to each other, the arc interface sizes of the two plates are exactly the same, and the processed butt surfaces of the two plates match each other and are smooth and flat.

[0054] S2: Workpiece assembly;

[0055] S201: Use 1000-2000# sandpaper to polish the interface to be welded to remove pollutants such as oxides and rust until the interface is bright.

[0056] S202: ultrasonically clean the polished high entropy alloy and the stainless steel plate to be welded at a frequency of 20 kHz for 5 minutes to remove pollutants such as oil stains, and then wipe the interface to be welded with petroleum ether or other organic solvents, and blow dry immediately after wiping;

[0057] S203: Figure 2 As shown, the wiped high entropy alloy and stainless steel metal plates are assembled to ensure that the interfaces to be welded of the metal plates are aligned and overlapped.

[0058] S3: Vacuum welding;

[0059] S301: Clamp and fix the assembled high entropy alloy and stainless steel metal plate on the welding fixture, place the fixture and the metal plate into the vacuum chamber of the electron beam welding machine after fixation, and start the multi-stage vacuum system to evacuate;

[0060] S302: When the vacuum degree of the vacuum chamber reaches 5×10 -2 Pa, turn on the electron gun high voltage system, adjust the focusing current, locate the focusing position to the flat surface, set the welding voltage to 60 kV, and the welding current to 5-20 mA to ensure that the weld is fully melted without obvious concave or convex, and control the electron beam to weld the high entropy alloy and stainless steel along the arc weld.

[0061] S4: Finish welding and keep warm, then take out the welded workpiece;

[0062] After welding is completed, keep the workpiece in the vacuum chamber for 15 minutes and then take it out.

[0063] In summary, the process of the present invention is simple and easy to implement. Compared with the process of adding an intermediate metal layer or complex welding process control, the arc weld design of the present invention is easy to process and implement, is suitable for large-scale industrial production, and has high practicality and promotion value.

[0064] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent replacement and improvement made to the above embodiments without departing from the content of the technical solution of the present invention, based on the technical essence of the present invention, within the spirit and principles of the present invention, still fall within the protection scope of the technical solution of the present invention.

Claims

1. A method for electron beam welding of a high entropy alloy and a stainless steel metal plate, characterized in that: The steps of the electron beam welding method of a high entropy alloy and a stainless steel metal plate include: Step 1: prepare high entropy alloy and stainless steel metal plates of the same size, and process a continuous arc-shaped welding interface on the high entropy alloy and stainless steel metal plates; Step 2: Grind the interface to be welded with sandpaper, perform ultrasonic cleaning on the polished high entropy alloy and stainless steel metal plates, wipe the ultrasonically cleaned high entropy alloy and stainless steel metal plates with an organic solvent, and blow dry immediately after wiping; Step 3: Align the wiped high entropy alloy and stainless steel metal plate welding machine surfaces for assembly, clamp and fix the assembled high entropy alloy and stainless steel metal plates on the welding fixture and place them in the vacuum chamber of the electron beam welder, start the multi-stage vacuum system to evacuate until the pressure in the vacuum chamber of the electron beam welder reaches the preset value; Step 4: Turn on the electron gun high voltage system, adjust the focusing current, locate the focusing position to the flat surface, select the corresponding welding parameters, control the electron beam to weld the high entropy alloy and the stainless steel metal plate along the arc weld, and keep the temperature in the vacuum chamber after welding; Step 5: After the insulation is completed, the workpiece is taken out to complete the electron beam welding of the high entropy alloy and the stainless steel.

2. The electron beam welding method for high entropy alloy and stainless steel metal plate according to claim 1, characterized in that: Step 1: Each adjacent semicircular arc interface between the high entropy alloy and the stainless steel metal plate is tangent, and the arc-shaped interface to be welded between the high entropy alloy and the stainless steel metal plate has the same size.

3. The electron beam welding method for high entropy alloy and stainless steel metal plate according to claim 1, characterized in that: The mesh number of the sandpaper used for polishing in step 2 is 1000-2000 mesh, the ultrasonic cleaning frequency is 20 kHz, the cleaning time is 5 minutes, and the organic solvent is petroleum ether.

4. The electron beam welding method for high entropy alloy and stainless steel metal plate according to claim 1, characterized in that: The preset pressure value in step 3 is 5×10 -2 Pa.

5. The electron beam welding method for high entropy alloy and stainless steel metal plate according to claim 1, characterized in that: In step 4, the welding voltage of the welding process is 60 kV, the welding current is 5-20 mA, and the holding time is 15 min.

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