A steel / titanium dissimilar metal laser additive-welding method

Abstract

The application provides a steel / titanium dissimilar metal laser additive-welding method, which comprises the following steps: cleaning a to-be-bonding surface of a base material, preparing a pure V transition layer on a to-be-welding surface of a titanium alloy plate by using laser additive, polishing the transition layer on the surface of the titanium alloy plate to obtain a smooth transition layer, and welding the titanium alloy with the steel by using laser welding after the titanium alloy is prepared with the transition layer. The application breaks through the limitation of welding the titanium alloy with a pure V strip or V block, and prepares the transition layer by using the laser additive method to form metallurgical bonding with the titanium alloy base body. Due to the infinite solid solution characteristics of Ti and V, the bonding strength between the transition layer and the base body is high. The preparation of the pure V transition layer isolates the mutual diffusion reaction of Fe and Ti during welding, the method of laser welding helps to obtain a more uniform temperature field and improve the stability of the welding process, reduces the generation of intermetallic compounds, makes the welding interface microstructure mainly composed of Fe-V solid solution with better plastic and toughness performance, and greatly improves the mechanical properties of the joint.

Description

Technical Field

[0001] This invention relates to the field of dissimilar metal welding technology, and more particularly to a laser additive welding method for steel / titanium dissimilar metals. Background Technology

[0002] Steel / titanium welding is an important topic in dissimilar metal joining, and its composite structures are widely used in industry and daily life. Titanium alloys and steel are important engineering materials. Titanium alloys have low density, high specific strength, and good high-temperature resistance and corrosion resistance; steel, as the most common and widely used ferrous metal, has good mechanical properties and weldability, making it the most widely used metal material in industrial manufacturing and social construction. Steel-titanium dissimilar metal joining structures can fully utilize the performance advantages of both materials, saving materials, reducing weight, lowering energy consumption, and reducing pollution. Therefore, in recent years, more and more products have adopted steel / titanium welding, demonstrating unique advantages and significant economic benefits in petrochemicals, aerospace, nuclear industry, transportation, and shipbuilding, and has shown broad application prospects in various industries.

[0003] During steel / titanium welding, Fe-Ti intermetallic compounds are inevitably formed. These compounds are highly brittle and are the main areas for crack initiation and propagation. Therefore, suppressing the formation of intermetallic compounds at the interface is of great significance for improving the performance of titanium-steel welded joints and promoting the application of titanium-steel composite structures. Laser welding, as an advanced joining technology, has advantages such as high energy density, rapid heating / cooling rates, high welding precision, and small post-weld deformation, and has been widely used in modern industry in recent years. Given the significant difference in melting points between titanium and steel, during welding, the laser beam is biased towards the lower-melting-point steel base material, causing the steel base material to connect via self-fusion welding. The higher-melting-point titanium alloy base material is only slightly melted or not melted, and the molten steel base material spreads to the surface of the titanium alloy base material to form a connection. This self-fusion welding method avoids the mixing of liquid titanium and iron atoms, suppresses the growth of brittle intermetallic compounds, and can obtain titanium-steel welded joints with good performance. However, further research has found that the welding process (especially butt welding) suffers from problems such as limited joint adaptability and low molten pool stability. Instability is a common phenomenon in the laser welding process of dissimilar metals such as titanium and steel. On the other hand, although the rapid heating / cooling characteristic of laser welding has a positive effect on suppressing the formation of brittle intermetallic compounds at the interface, the localized heat source of the laser causes different welding thermal cycles at different locations on the interface, resulting in brittle intermetallic compounds of varying thickness, morphology, and even composition. This heterogeneous distribution of brittle intermetallic compound layers is detrimental to the precise control of the interface's microstructure and mechanical properties. Therefore, solving the problem of heterogeneous distribution of intermetallic compound layers, suppressing the rapid growth of intermetallic compounds, and improving the strength of steel-titanium laser-welded joints are of great significance for promoting the application of steel-titanium composite structures.

[0004] The metallurgical control method of introducing alloying elements is one approach to address the problem of rapid growth of Fe-Ti intermetallic compounds during welding, which leads to deterioration of joint performance. Vanadium is the preferred element for controlling the properties of intermetallic compounds in titanium-steel weld joints because a vanadium interlayer can prevent the formation of intermetallic compounds. Current research, such as the vanadium-interlayer-based laser welding method for titanium alloys and stainless steel dissimilar metals (application number 201710559216.5), typically introduces vanadium using pure vanadium strips or pure vanadium blocks. First, using pure vanadium strips requires double-pass laser welding, which significantly increases the assembly difficulty considering the high precision requirements of laser welding. Second, using vanadium strips is difficult to implement for many dissimilar structures, resulting in poor structural adaptability. Third, the thickness of the vanadium layer greatly affects the mechanical properties of the joint and is not easily controlled. If the vanadium layer is too thin, it completely dissolves into the molten pool during welding, temporarily blocking the reaction between Fe and Ti. Although this improves mechanical properties to some extent, the key problem of the interfacial structure containing brittle Fe-Ti intermetallic compounds remains unresolved. If the V-layer is too thick, unmelted V-layers will remain at the joint connection, acting as a weak point and making the joint highly susceptible to fracture at the intermediate layer, thus worsening the joint performance. Therefore, there is an urgent need to design a steel / titanium dissimilar metal welding method with low assembly difficulty, high adaptability, and good controllability to further promote the use of steel / titanium joints. Summary of the Invention

[0005] To address the aforementioned technical problems, a laser additive welding method for steel / titanium dissimilar metals is provided. This method cleverly transforms the Fe / Ti problem of the weld joint into an Fe / V problem by preparing a robust laser cladding layer on the titanium alloy surface. The Fe-V solid solution generated during welding exhibits better toughness and crack resistance. Using laser welding helps to obtain a more uniform temperature field. Through the combined technological and metallurgical methods described above, the interfacial reaction of the joint is controlled to obtain a high-performance joint that meets practical production needs.

[0006] The technical means employed in this invention are as follows:

[0007] A laser additive welding method for steel / titanium dissimilar metals, specifically comprising the following steps:

[0008] Step 1: Clean the surfaces of the base materials to be bonded: Clean the titanium alloy plate and the steel plate to be welded before welding;

[0009] Step 2: Prepare a pure V transition layer on the surface of the titanium alloy plate to be welded using laser additive manufacturing: Fix the titanium alloy plate to be welded, and use a laser to melt the fed pure V powder to form a pure V transition layer on the surface of the titanium alloy plate. The thickness and composition of the pure V transition layer are controlled by adjusting the parameters of the laser output power, defocusing amount, cladding speed, cladding times and powder feeding amount.

[0010] Step 3: Grind the transition layer on the surface of the titanium alloy plate to obtain a smooth transition layer.

[0011] Step 4: Welding the titanium alloy with the transition layer to the steel using laser welding: The titanium alloy plate to be welded with the smoothed transition layer is butt-jointed with the steel plate to be welded using a fixture and fixed with a clamp. After adjusting the process parameters such as laser power, defocusing amount, welding speed, spot position, and protective gas flow, steel / titanium laser autofusion welding is performed.

[0012] Furthermore, in step one, the pre-welding cleaning step of the titanium alloy plate to be welded is as follows: after sanding the side of the titanium alloy plate smooth with sandpaper, clean the surface of the titanium alloy plate with acetone to remove stains, and then rinse with running water and blow dry.

[0013] Furthermore, in step one, the specific steps for pre-welding treatment of the steel plate to be welded are as follows: after sanding the side of the steel plate smooth with sandpaper, clean the surface of the steel plate with acetone to remove stains, and then rinse with running water and blow dry.

[0014] Furthermore, in step two, the laser used in laser additive manufacturing is any one of a CO2 laser, a YAG solid-state laser, a fiber laser, and a semiconductor laser.

[0015] Furthermore, in step two, the powder feeding method is either pre-placed powder or synchronous powder feeding.

[0016] Furthermore, in step two, the V powder used is 50-400 mesh.

[0017] Furthermore, in step two, the laser power used is 1000-2000W, the cladding speed is 4-12mm / s, the defocusing amount is 30-60mm, the number of cladding cycles is 1-10, and the cladding layer thickness is 0.1-10mm.

[0018] Furthermore, in step three, the method for smoothing the titanium used to prepare the transition layer is to use wire cutting to remove the excess parts of the side surface and mating surface of the cladding layer, and then use sandpaper to polish out the exposed titanium and cladding layer metal.

[0019] Furthermore, in step four, the laser is any one of a CO2 laser, a YAG solid-state laser, a fiber laser, and a semiconductor laser.

[0020] Furthermore, in step four, the specific process parameters are as follows: laser power 2000-4000W, defocusing amount 0-20mm, welding speed 0.3-5m / min, steel side offset 0-0.5mm, shielding gas is pure argon, shielding gas flow rate is 20L / min, and the shielding gas protects the back side of the weld.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] This invention overcomes the limitations of welding pure V strips or blocks to titanium alloys. It employs laser additive manufacturing to prepare a transition layer that forms a metallurgical bond with the titanium alloy matrix. Due to the infinite solid solution properties of Ti and V, the bond strength between the transition layer and the matrix is ​​high. During welding, the preparation of the pure V transition layer isolates the interdiffusion reaction of Fe and Ti. Simultaneously, the laser welding method helps to obtain a more uniform temperature field, improves the stability of the welding process, and reduces the formation of few intermetallic compounds. This results in the weld interface microstructure being primarily composed of Fe-V solid solutions with good ductility and toughness. The precipitation of the originally brittle Fe-Ti intermetallic compounds at the steel / titanium dissimilar metal welding interface is suppressed, significantly improving the mechanical properties of the joint.

[0023] This invention utilizes laser additive manufacturing to prepare a dense, pure V-transition layer on the titanium surface, offering the advantage of flexible and controllable transition layer thickness. During welding with steel, it cleverly transforms the Fe-Ti interface structure into an Fe-V interface structure, thereby improving the mechanical properties of the steel-titanium dissimilar metal weld joint, such as tensile properties. The use of V-powder provides strong structural adaptability and ease of control. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of the welding method of the present invention.

[0026] Figure 2 This is a schematic diagram of the transition joint obtained by laser additive manufacturing according to the present invention.

[0027] Figure 3 This is a schematic diagram of the coating obtained after cooling, trimming, and polishing.

[0028] Figure 4 This is a schematic diagram of the laser welding process.

[0029] Figure 5 It is the actual cross-section of the welded joint.

[0030] In the figure: 1. Titanium alloy plate to be welded, 2. Steel plate to be welded, 3. V cladding layer, 4. Clad layer after grinding, 5. Laser used for cladding, 6. Powder feeder, 7. Laser used for welding, 8. Backing plate, 9. Shielding gas. Detailed Implementation

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0034] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0036] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0037] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0038] like Figures 1-4 As shown, this invention provides a laser additive welding method for steel / titanium dissimilar metals, comprising the following steps:

[0039] Step 1: Clean the surfaces of the base material to be bonded.

[0040] The titanium alloy plate 1 to be welded and the steel plate to be welded are cleaned before welding. The specific steps are as follows: after sanding the side of the titanium alloy plate 1 with sandpaper, clean the surface of the titanium alloy plate 1 with acetone to remove stains, and then rinse with running water and blow dry.

[0041] The specific steps for pre-welding treatment of the steel plate 2 to be welded are as follows: after sanding the side of the steel plate 2 with sandpaper, clean the surface of the steel plate 2 with acetone to remove stains, and then rinse with running water and blow dry.

[0042] The thickness of the steel plate 1 to be welded is 1-6mm, and the thickness of the steel plate 2 to be welded is 1-6mm. In this embodiment, the thickness of the titanium alloy plate 1 to be welded is 3mm and the thickness of the steel plate 2 to be welded is 3mm, which will be used as an example for introduction.

[0043] Step 2: Prepare laser cladding layer 3 on the side of the titanium alloy plate 1 to be welded.

[0044] After cleaning, the titanium alloy plate 1 to be welded is vertically fixed. A fiber laser and powder feeder are activated to prepare the surface cladding layer 3. The laser can be any one of a CO2 laser, YAG solid-state laser, fiber laser, or semiconductor laser. Pure V powder of 50-400 mesh is fed out using the powder feeder. The laser power is 1000-2000W, the cladding speed is 4-12 mm / s, the defocusing distance is 30-60 mm, the number of cladding passes is 1-10, and the cladding layer thickness is 0.1-10 mm. The titanium alloy plate 1 to be welded is removed after the surface cladding layer 3 is prepared. Figure 2 As shown, after the above treatment, the titanium alloy plate 1 to be welded has a cladding layer 3.

[0045] Step 3: Polish the cladding layer 3 on the surface of the titanium alloy plate 1 again to obtain a smooth transition layer 4.

[0046] The method for further smoothing the titanium used to prepare the transition layer is as follows: Excess portions of the cladding layer's sides and mating surfaces are removed using wire cutting, and then sanded to expose the bare titanium alloy and cladding metal. For example... Figure 3 As shown, after the above treatment, a titanium alloy plate 1 with a smooth cladding layer 4 is obtained.

[0047] Step 4: Butt weld the titanium alloy with the transition layer to the steel using laser welding:

[0048] The titanium alloy plate 1 to be welded, with a smoothed transition layer 4, is butt-welded with the steel plate 2 using a fixture. The plate is fixed in place and laser welded. The process parameters, including laser power, defocusing amount, welding speed, spot position, and shielding gas flow rate, are adjusted to perform laser autofusion welding of the steel / titanium dissimilar metals. During welding, the heat source is concentrated on the surface of the steel base material. Both the titanium base material and the cladding layer remain solid. The presence of the transition layer 4 isolates the reaction between liquid Fe and solid Ti, thus inhibiting the formation of Fe-Ti intermetallic compounds. The interface is formed by the reaction of solid V with the molten metal, resulting in a metallurgical bond in the form of an Fe-V solid solution, thus obtaining the welded joint. Considering the above factors, the selected process parameters for welding are: laser power 2000W~4000W, defocusing amount 0~20mm, welding speed 0.3m / min~5m / min, beam offset on the steel side 0~0.5mm, shielding gas is pure argon, shielding gas flow rate is 20L / min, and the shielding gas protects the back side of the weld.

[0049] The laser mentioned in this step is any one of a CO2 laser, a YAG solid-state laser, a fiber laser, and a semiconductor laser.

[0050] Example 1

[0051] A laser additive welding method for steel / titanium dissimilar metals.

[0052] Step 1: Select TA2 titanium alloy plate and Q235 steel plate, both with a thickness of 3mm, and clean the surface of the titanium alloy plate 1 and the steel plate 2 to be welded according to the above method before welding.

[0053] Step 2: Pure V powder of 100-200 mesh is fed out using a carrier gas. The pure V powder is melted using a fiber laser to form a cladding layer on the titanium surface. The laser power is 1600W, the cladding speed is 10mm / s, the defocusing distance is 40mm, and the powder feeding rate is 9.36g / min. The V powder is fed in at the front of the laser travel direction. The cladding is performed 5 times. Each cladding is cooled to room temperature before the next cladding begins.

[0054] Step 3: After cutting off the protruding parts of the cladding layer using wire cutting, polish the cladding layer with sandpaper until the metal luster is exposed. The thickness of the transition layer 4 is 3±0.1mm.

[0055] Step 4: The processed titanium alloy plate 1 to be welded is butt-jointed with the steel plate to be welded using a fixture. The plate is clamped and self-fusion welded using a CW-CBW-6000G-51 fiber laser with a laser power of 3500W, a welding speed of 1.2m / min, a focusing mode, and an offset of 0.1mm towards the steel side.

[0056] like Figure 5 As shown, a well-formed steel / titanium butt joint was obtained using the above welding parameters, with no obvious defects such as lack of fusion, undercut, or porosity. Observation of the interface microstructure revealed that the interface was mainly based on Fe-V solid solution, with some carbides and intermetallic compounds dispersed in it. No obvious microcracks were generated. The tensile strength of the butt joint was tested, with a sample width of 10 mm, and the maximum tensile strength of the joint reached 393.2 MPa.

[0057] Example 2

[0058] A laser additive welding method for steel / titanium dissimilar metals.

[0059] Step 1: Select TA2 titanium alloy plate and 304 stainless steel plate, both with a thickness of 3mm, and clean the surface of the titanium alloy plate 1 and the steel plate 2 to be welded according to the above method before welding.

[0060] Step 2: Pure V powder of 100-200 mesh is fed out using a carrier gas. The pure V powder is melted using a fiber laser to form a cladding layer on the titanium surface. The laser power is 1600W, the cladding speed is 10mm / s, the defocusing distance is 40mm, and the powder feeding rate is 9.36g / min. The V powder is fed in at the front of the laser travel direction. The cladding is performed 5 times. Each cladding is cooled to room temperature before the next cladding begins.

[0061] Step 3: After cutting off the protruding parts of the cladding layer using wire cutting, polish the cladding layer with sandpaper until the metal luster is exposed. The thickness of the transition layer 4 is 3±0.1mm.

[0062] Step 4: The processed titanium alloy plate 1 to be welded is assembled with the stainless steel plate to be welded using a fixture. The plate is clamped with a clamp and self-fusion welding is performed using a CW-CBW-6000G-51 fiber laser. The selected laser power is 4000W, the welding speed is 2m / min, the focusing mode is used, and the offset is 0.1mm towards the steel side.

[0063] No defects such as porosity, lack of fusion, and cracks were found in the joint after welding. No continuous intermetallic compounds were observed in the interface area. The tensile strength of the joint was 406.3 MPa.

[0064] Example 3

[0065] A laser additive welding method for steel / titanium dissimilar metals.

[0066] Step 1: Select TC4 titanium alloy plate and 304 stainless steel plate, both with a thickness of 2mm, and clean the surface of the titanium alloy plate 1 and the steel plate 2 to be welded according to the above method before welding.

[0067] Step 2: Pure V powder of 50-400 mesh is fed out using a carrier gas. The pure V powder is melted using a fiber laser to form a cladding layer on the titanium surface. The laser power is 1400W, the cladding speed is 11mm / s, the defocusing distance is 35mm, and the powder feeding rate is 10.08g / min. The V powder is fed in at the front of the laser travel direction. The cladding is performed 5 times. Each cladding is cooled to room temperature before the next cladding begins.

[0068] Step 3: After cutting off the protruding parts of the cladding layer using wire cutting, polish the cladding layer with sandpaper until the metal luster is exposed. The thickness of the transition layer 4 is 3±0.1mm.

[0069] Step 4: The processed titanium alloy plate 1 to be welded is assembled with the steel plate to be welded using a fixture. The plate is clamped and self-fusion welded using a CW-CBW-6000G-51 fiber laser with a laser power of 2000W, a welding speed of 1.5m / min, a focusing mode, and an offset of 0.1mm towards the steel side.

[0070] Using the above welding parameters, a well-formed steel / titanium butt joint was obtained, with no obvious defects such as lack of fusion, undercut, or porosity. Observation of the interface microstructure revealed that the interface was mainly based on Fe-V solid solution, with some carbides and intermetallic compounds dispersed in it. No obvious microcracks were generated. The tensile strength test of the butt joint showed that the maximum tensile strength of the joint reached 399.1 MPa.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A laser additive welding method for steel / titanium dissimilar metals, characterized in that, Includes the following steps: Step 1: Clean the surfaces of the base materials to be bonded: Clean the titanium alloy plate and the steel plate to be welded before welding; Step 2: Prepare a pure V transition layer on the surface of the titanium alloy plate to be welded using laser additive manufacturing: Fix the titanium alloy plate to be welded, and use a laser to melt the fed pure V powder to form a pure V transition layer on the surface of the titanium alloy plate. The thickness and composition of the pure V transition layer are controlled by adjusting the parameters of the laser output power, defocusing amount, cladding speed, cladding times and powder feeding amount. Step 3: Grind the transition layer on the surface of the titanium alloy plate to obtain a smooth transition layer. Step 4: Welding the titanium alloy with the transition layer to steel using laser welding: The titanium alloy plate to be welded with the smoothed transition layer is butt-welded to the steel plate using a fixture and fixed with a clamp. After adjusting the process parameters such as laser power, defocusing amount, welding speed, spot position, and shielding gas flow rate, steel / titanium laser autofusion welding is performed. During welding, the heat source is concentrated on the surface of the steel base material, while the titanium base material and the cladding layer remain solid. The presence of the transition layer isolates the reaction between liquid Fe and solid Ti, thereby inhibiting the formation of Fe-Ti intermetallic compounds. The interface is formed by the reaction between solid V and molten metal, forming a metallurgical bond in the form of Fe-V solid solution. The specific process parameters are: laser power 2000-4000W, defocusing amount 0-20mm, welding speed 0.3-5m / min, steel side offset 0-0.5mm, shielding gas is pure argon, shielding gas flow rate is 20L / min, and the shielding gas protects the back side of the weld.

2. The steel / titanium dissimilar metal laser additive welding method according to claim 1, characterized in that, In step one, the pre-welding cleaning of the surface of the titanium alloy plate to be welded is as follows: after sanding the side of the titanium alloy plate with sandpaper, clean the surface of the titanium alloy plate with acetone to remove stains, and then rinse with running water and blow dry.

3. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step one, the specific steps for pre-welding treatment of the steel plate to be welded are as follows: after sanding the side of the steel plate with sandpaper, clean the surface of the steel plate with acetone to remove stains, and then rinse with running water and blow dry.

4. The steel / titanium dissimilar metal laser additive welding method according to claim 1, characterized in that, In step two, the laser used for laser additive manufacturing is any one of a CO2 laser, a YAG solid-state laser, a fiber laser, and a semiconductor laser.

5. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step two, the powder feeding method is either pre-powdered powder or synchronous powder feeding.

6. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step two, the V powder used is 50-400 mesh.

7. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step two, the laser power used is 1000-2000W, the cladding speed is 4-12mm / s, the defocusing amount is 30-60mm, the number of cladding times is 1-10, and the thickness of the pure V transition layer is 0.1-10mm.

8. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step three, the method for smoothing the titanium of the prepared transition layer again is to use wire cutting to remove the excess parts of the side and mating surface of the pure V transition layer, and then use sandpaper to polish out the exposed titanium and pure V transition layer metal.

9. The laser additive welding method for steel / titanium dissimilar metals according to claim 1, characterized in that, In step four, the laser is any one of a CO2 laser, a YAG solid-state laser, a fiber laser, and a semiconductor laser.

Images