Preparation method and application of micro-pit texture reinforced dissimilar metal welded joint
By building a micro pit texture on the bevel of the different metal welded joint, the problem of crack propagation in the different metal welded joint is solved, and the strength and mechanical properties of the welded joint are improved.
Patent Information
- Application Number
- CN202510621435.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-08-08
AI Technical Summary
The heterogeneous metal welded joints generate brittle intermetallic compounds at the interface, causing cracks to proliferate and affect the mechanical properties of the joints. It is difficult for the prior art to effectively suppress them.
Micro pit texture is constructed on the bevel of different metal weldments, and the micro pit texture is etched on the bevel by mask electrolysis, and then welded to divide the weld interface to hinder crack propagation.
It improves the strength and toughness of different metal welded joints, reduces the aggregation of defects such as cracks and pores, and enhances the mechanical properties of the joints.
Smart Images
Figure CN120438744A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of dissimilar metal welding, in particular to a preparation method and application of a micro-pit texture reinforced dissimilar metal welded joint. Background Art
[0002] Dissimilar metal welding has important applications in areas such as automotive lightweighting, petrochemicals, and aerospace. However, due to the significant differences in physical and chemical properties between dissimilar metals, a large amount of brittle intermetallic compounds is generated at the weld interface, accompanied by defects such as cracks and pores. Under the action of external forces, cracks rapidly propagate along the intermetallic compounds, seriously affecting the mechanical properties of the joint. While optimizing welding process parameters, adding alloy brazing filler metals, and improving groove structure can improve joint quality and mechanical properties to a certain extent, it is still difficult to effectively inhibit crack propagation in the intermetallic compounds at the interface. Summary of the Invention
[0003] The present invention aims to provide a preparation method and application of a micro-pit texture-reinforced dissimilar metal weld joint, which is used to improve the wettability of the groove surface and hinder the propagation of cracks in the intermetallic compounds at the joint interface.
[0004] In order to solve the above technical problems, the specific solution adopted by the present invention is: a method for preparing a micro-pit texture reinforced dissimilar metal weld joint, comprising the following steps:
[0005] 1) Opening a groove on the butt joint of dissimilar metal weldments;
[0006] 2) Constructing micro-pit texture on the groove by mask electrolysis;
[0007] 3) Weld the grooves of dissimilar metal weldments with brazing filler metal.
[0008] Preferably, the material of the dissimilar metal weldment is aluminum-steel, copper-steel, or aluminum-copper.
[0009] Preferably, the specifications of the dissimilar metal weldments are plates, bars, and pipes.
[0010] Preferably, the shape of the groove is V-shaped, U-shaped, or X-shaped; the angle of the groove is 20°-90°.
[0011] Preferably, in step 2), a mask plate, a metal foam layer and a pressing plate are first laid on the groove in sequence, a mask hole is set on the mask plate, and a drainage channel is set on the pressing plate; then the electrolyte is infiltrated into the mask hole through the drainage channel and the metal foam layer, and an electric field is formed by the dissimilar metals and the metal foam layer to generate an electrochemical reaction, thereby etching a micro-pit texture on the groove.
[0012] Preferably, the mask holes are evenly spaced on the mask plate; the shapes of the mask holes are circular, square, or polygonal; the maximum spacing between the mask holes is 0.4-1 mm, and the spacing between adjacent mask holes is 0.1-2 mm.
[0013] Preferably, the depth of the micropits in the micropit texture is 0.1-0.2 mm.
[0014] Preferably, during the electrolysis process, the electrolyte flow rate is 0.5 m / s-5.0 m / s, the current is 0.5 A-3.0 A, and the voltage is 2 V-36 V.
[0015] Preferably, the micro-pit texture is constructed on a single slope surface of the dissimilar metal joint, or the micro-pit texture is constructed on both slope surfaces of the dissimilar metal joint.
[0016] Application of any of the above-mentioned methods for preparing micro-pit texture-reinforced dissimilar metal weld joints in automobiles, aerospace, and chemical equipment.
[0017] The present invention constructs a micro-pit texture on the groove of a dissimilar metal weldment and then welds the groove. After welding, the interface between the weldment and the weld is divided into a grid of squares by the micro-pit texture. This serves to hinder the propagation of cracks at the joint interface under stress and improve the mechanical strength of the dissimilar metal welded joint. Specifically, the present invention isolates welding defects such as cracks and pores within the texture array, thereby alleviating the concentration of welding defects at the joint interface and hindering the propagation of cracks in the intermetallic compound layer, thereby improving the toughness of the dissimilar metal welded joint. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 Schematic diagram of groove processing of dissimilar metal weldments in the present invention;
[0019] Figure 2 Schematic diagram of the process of constructing a micro-pit texture on a groove by masked electrolysis in the present invention;
[0020] Figure 3 Schematic diagram of the structure of the micro-pit texture constructed on a single-sided groove by mask electrolysis in the present invention;
[0021] Figure 4 Schematic diagram of the structure of the micro-pit texture constructed on the double-sided side openings by mask electrolysis in the present invention;
[0022] Figure 5 Schematic diagram of the welding process in the present invention;
[0023] Figure 6 Schematic diagram of the cross-sectional structure of the dissimilar metal joint in the present invention after constructing the micro-pit texture and welding;
[0024] Markings in the figure: 1. Dissimilar metal welding parts, 2. Groove, 3. Metal foam layer, 4. Drainage channel, 5. Press plate, 6. Mask hole, 7. Mask plate, 8. Micro-pit texture, 9. Welding wire, 10. Heating tool, 11. Shielding gas, 12. Substrate, 13. Intermetallic compound, 14. Filler solder, 15. Welding crack. DETAILED DESCRIPTION
[0025] The following two examples illustrate the method for preparing the micro-pit texture reinforced dissimilar metal weld joint of the present invention:
[0026] Example 1
[0027] In this embodiment, a method for preparing a micro-pit texture-reinforced aluminum / steel weld joint is proposed, and the specific steps are as follows:
[0028] (1) The raw materials are 6061-T6 aluminum alloy and Q235 steel as the dissimilar metal welding parts 1. The size of the steel plate and the aluminum plate are 100mm×80mm×4mm. The connection method is butt joint. The following openings are made on the butt joint surfaces of the aluminum plate and the steel plate: Figure 1 The V-shaped groove 2 shown has an inclination angle of 45° and a surface roughness of Ra=2.8 μm. The micro-pit texture 8 is constructed only on the groove 2 surface of the steel plate.
[0029] (2) A micro-pit texture 8 is constructed on the groove 2 of the steel plate by mask electrolysis. The mask plate 7 is made of polyvinyl chloride, the electrolyte composition is NaCl solution, the spacing of the mask holes 6 is 1.0 mm, and the mask holes 6 are evenly distributed on the entire groove 2 in a mesh shape. Figure 2 As shown, during the mask electrolysis process, the electrolyte enters the metal foam layer 3 (copper foam layer is used in this embodiment) through the drainage channel 4 on the pressing plate 5, and then penetrates into the mask hole 6. The width of the mask hole 6 is 0.4 mm, the electrolyte flow rate is 1.0 m / s, the current during the electrolysis process is 1.8 A, the electrolysis voltage is 15 V, the steel plate and the copper foam form an electric field, and an electrochemical reaction occurs. The reaction time is 420 seconds, and a micro-pit texture 8 with a depth of 0.2 mm is etched on the steel plate. The preparation process and micro-pit morphology are shown in FIG. Figure 3 shown.
[0030] (3) Figure 5 As shown, laser wire welding technology is used to connect the aluminum / steel heterogeneous materials laid on the substrate 12, with laser as the heating tool 10, the inclination angle of the laser beam to the table is 80°, the protective gas 11 is a mixed atmosphere of 50% N2 + 50% CO2, the gas supply rate is 10 L / min, N2 gas is passed under the weld pool, and the gas supply rate is 3.0 L / min to ensure that the weld pool is not oxidized by air during the solidification process. The filler metal in the groove 2 is Al-5Si alloy welding wire 9 with a wire diameter of 1.2 mm.
[0031] like Figure 6 As shown, through this embodiment, the welding cracks 15 such as cracks and pores distributed in the filling solder 14 and the intermetallic compound 13 are isolated in the micro-pit texture 8 array, thereby alleviating the degree of aggregation of welding defects in the joint interface, hindering the expansion of cracks in the intermetallic compound 13 layer, and thus improving the strength and toughness of the dissimilar metal welding joint.
[0032] Example 2
[0033] In this embodiment, a method for preparing a micro-pit texture-reinforced weld joint of Ti6Al4V alloy and 304 steel is proposed. The micro-pit texture 8 is constructed on two surfaces of the weld groove to improve the interface bonding strength. The specific steps are as follows:
[0034] (1) The materials selected are Ti6Al4V titanium alloy and 304 stainless steel, both of which have dimensions of 150 mm × 60 mm × 5 mm. The connection method is butt-jointing. A V-shaped groove 2 is processed at the ends of the titanium alloy and stainless steel weldments. The angle of the groove 2 is 300, and the surface roughness is controlled to Ra = 3.2 μm.
[0035] (2) A micro-pit texture 8 was designed on both sides of the groove between the steel plate and the alloy plate by mask electrolysis. The mask material was polyimide, the mask holes 6 were in the shape of a square with a side length of 0.8 mm, the hole spacing was 1.2 mm, and they were evenly distributed on both sides of the groove. The electrolyte was a Na2SO4 solution, which was transported to the copper foam layer through the drainage channel 4 at a flow rate of 1.5 m / s and infiltrated into the mask holes 6. The copper foam layer and the stainless steel formed an electric field. The electrolysis voltage was 20 V, the current was 2.5 A, and the electrolysis time was 300 seconds. A micro-pit texture 8 with a depth of 0.15 mm was etched on both sides of the groove between the titanium alloy and the stainless steel. Figure 4 shown.
[0036] (3) Metallurgical electrode gas shielded welding is adopted, and the welding wire 9 is ER308L with a diameter of 1.0 mm. Argon gas is passed above the weld pool at a gas supply rate of 15 L / min, and argon gas is passed below the weld pool at a gas supply rate of 5 L / min to prevent the titanium alloy and stainless steel from being oxidized. After the brazing filler metal is melted, the groove 2 is filled. The micro-pit texture 8 divides the interface into several 1.5 mm × 1.5 mm square units, which hinders the expansion of cracks at the joint interface.
[0037] Compared with Example 1, Example 2 uses different dissimilar materials, different welding parameters and heating methods to obtain micro-pit structures with different shapes, sizes, spacings and arrangements, which are suitable for different welding materials and application scenarios, illustrating the wide applicability of this invention method.
Claims
1. A method for preparing a micro-pit texture-reinforced dissimilar metal weld joint, characterized by: The following steps are involved: 1) Opening a groove on the butt joint of dissimilar metal weldments; 2) Constructing micro-pit texture on the groove by mask electrolysis; 3) Weld the grooves of dissimilar metal weldments with brazing filler metal.
2. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 1, characterized in that: The materials of dissimilar metal weldments are aluminum-steel, copper-steel, and aluminum-copper.
3. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 1, characterized in that: The specifications of dissimilar metal weldments are plates, bars and pipes.
4. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 1, wherein: The shapes of the grooves are V-shaped, U-shaped, and X-shaped; the angles of the grooves are 20°-90°.
5. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 1, wherein: In step 2), a mask plate, a metal foam layer and a pressing plate are first laid on the groove in sequence, a mask hole is set on the mask plate, and a drainage channel is set on the pressing plate; then the electrolyte is infiltrated into the mask hole through the drainage channel and the metal foam layer, and an electric field is formed by the dissimilar metals and the metal foam layer to generate an electrochemical reaction, thereby etching a micro-pit texture on the groove.
6. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 5, characterized in that: The mask holes are evenly spaced on the mask plate; the shapes of the mask holes are circular, square, and polygonal, the maximum spacing between the mask holes is 0.4-1 mm, and the spacing between adjacent mask holes is 0.1-2 mm.
7. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 5, characterized in that: The depth of the micropits in the micropit texture is 0.1-0.2 mm.
8. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 5, characterized in that: During the electrolysis process, the electrolyte flow rate is 0.5m / s-5.0m / s, the current is 0.5A-3.0A, and the voltage is 2V-36V.
9. The method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to claim 1, characterized in that: A micro-pit texture is constructed on a single-side slope surface of the dissimilar metal joint, or a micro-pit texture is constructed on both sides of the slope surface of the dissimilar metal joint.
10. Application of the method for preparing a micro-pit texture reinforced dissimilar metal weld joint according to any one of claims 1 to 9 in automobile, aerospace, and chemical equipment.