Titanium-steel composite plate welding method
By preparing a gradient transition layer during the welding of titanium-steel composite plates, the problem of brittle compound formation at the titanium-steel interface is solved, thereby improving the joint strength, toughness, and long-term stability. This method is suitable for pressure vessels, chemical equipment, and marine engineering.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
- Filing Date
- 2026-04-24
- Publication Date
- 2026-07-21
AI Technical Summary
Existing titanium-steel composite welding technologies suffer from interfacial brittleness and the formation of intermetallic compounds, which leads to a decrease in the plasticity and toughness of the welded joint, making it difficult to apply in fields such as pressure vessels, chemical equipment, and marine engineering. Existing transition layer methods also suffer from problems such as high heat input, insufficient coating density, and limited interfacial bonding strength.
A gradient transition layer was prepared on the titanium-steel interface using ultrasonic coupling cold spraying technology. The direct contact between Ti and Fe was blocked by a metallurgical buffer with gradually changing composition, thus constructing a Ti-Al-Ni-Fe composition gradient system and realizing the controllable adjustment of the interfacial thermo-chemical behavior.
It significantly inhibits the formation of TiFe-like brittle phases, improves the bonding strength and crack resistance of welded joints, ensures long-term service stability, and achieves reliable connection.
Smart Images
Figure CN122425379A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of titanium-steel composite plate welding technology, and particularly relates to a welding method for titanium-steel composite plates. Background Technology
[0002] In the welding process of existing titanium-steel composite materials, the significant difference in thermophysical parameters between titanium and steel, coupled with the ease with which elemental interdiffusion occurs under welding thermal cycling, leads to the formation of brittle intermetallic compound layers such as FeTi and Fe2Ti at the interface. This results in a significant decrease in the plasticity and toughness of the welded joint, and even interface delamination or brittle fracture, severely restricting the engineering applications of titanium-steel composite materials in pressure vessels, chemical equipment, and marine engineering. To improve these problems, existing technologies typically introduce intermediate transition layers such as aluminum or nickel at the welding interface. However, these transition layers are mostly prepared through thermal spraying, electroplating, or welding, which suffer from problems such as high heat input, insufficient coating density, and limited interfacial bonding strength. Furthermore, they are difficult to effectively suppress the formation and growth of metallic compounds at the titanium-steel interface during welding.
[0003] Specifically, current welding technologies for titanium-steel composite plates mainly include fusion welding and brazing, intermediate transition layer welding, and solid-state bonding. For example, patent CN101664852A uses a composite process of "fusion welding the titanium layer first, then silver brazing the steel layer." While this simplifies the process, the joint performance relies excessively on precious metal brazing filler metal, making it difficult to meet the high requirements of load-bearing structures for mechanical properties and long-term service stability. Patents CN103785962A and CN107984054A respectively attempt to introduce a solid metal transition layer (such as vanadium or high-nickel alloy) to achieve full penetration through fusion welding. Although this can effectively suppress the direct reaction between Ti and Fe, it still faces challenges in terms of precise control of the transition layer thickness, management of welding heat input, and process complexity.
[0004] To further optimize interface organization, more complex technical approaches have been proposed. Some studies (such as patents with publication numbers CN106001956A and CN113319405A) have attempted to employ multi-layer or multi-material composite transition structures; for example, preparing Cu / V powder composite layers through cold spraying or sequentially constructing copper-based and niobium-based transition layers using twin-wire welding. These methods aim to more precisely control interface reactions, but they often rely on specialized equipment or extremely complex welding processes, and the material systems are relatively fixed, making it difficult to flexibly adapt to diverse needs with different plate thicknesses and material combinations.
[0005] In addition, patent CN117206642A employs a step-by-step welding strategy, while patent CN117921165A introduces friction stir welding to achieve solid-state bonding. Although these methods have made progress in interface microstructure control, their process universality, equipment dependence, and applicability to complex structures remain limited.
[0006] In summary, while existing technologies have achieved some success in physically isolating the titanium-steel interface reaction, they generally suffer from the following shortcomings: the transition layer often relies on pre-prepared fixed-composition welding wire, brazing filler metal, or a solid intermediate layer, playing a primarily "passive" barrier role during welding. It is difficult to actively and precisely control the transition layer's compositional gradient, microstructure, and reaction behavior during the welding thermal cycle from the material system design perspective. This makes it difficult to simultaneously achieve process convenience and interface performance stability. Therefore, the industry urgently needs an innovative method that can prepare a weldable transition layer with good metallurgical compatibility with both titanium and steel substrates under low heat input conditions, and actively control the interface reaction path during subsequent welding, thereby achieving reliable connection while fundamentally ensuring joint strength, toughness, and long-term service stability. Summary of the Invention
[0007] To overcome the shortcomings of existing technologies, this invention provides a welding method for titanium-steel composite plates, which can achieve reliable connection while fundamentally ensuring the joint's strength, toughness, and long-term service stability.
[0008] The objective of this invention is achieved through the following technical solution: A welding method for titanium-steel composite plates includes the following steps: Bevels are machined in the areas to be welded on both the titanium and steel substrates, and the bevels undergo surface pretreatment. The steel substrate is butt-welded to form a continuous and dense steel weld layer; A gradient transition layer was prepared on the surface of the steel weld layer and its adjacent area near the titanium substrate using ultrasonic coupling cold spraying technology. The titanium substrate is capped by welding to form a titanium weld layer at the end of the gradient transition layer away from the steel weld layer.
[0009] Furthermore, surface pretreatment of the bevel includes: After the beveling process is completed, the beveling surface is mechanically ground and cleaned to remove oil, oxide film and contaminants, and to control the surface roughness of the beveling within the range of Ra1.6~6.3 or to achieve an equivalent sandblasting roughening state.
[0010] Furthermore, butt welding is performed using submerged arc welding, TIG welding, or laser welding; and / or During butt welding, the titanium substrate does not participate in the molten pool reaction.
[0011] Furthermore, the preparation of the gradient transition layer using ultrasonic coupling cold spraying technology includes: After the steel weld layer cools to room temperature, a gradient transition layer is prepared.
[0012] Furthermore, the preparation of the gradient transition layer using ultrasonic coupling cold spraying technology includes: Multiple layers of metal or alloy powders with different compositions are sequentially deposited using a cold spraying method to form a gradient transition layer with gradually changing composition along the thickness direction. During the cold spraying process, controlled ultrasonic vibrations are applied to the spraying deposition area through an ultrasonic transducer.
[0013] Furthermore, the frequency of the ultrasonic vibration is 15~40kHz, and the amplitude of the ultrasonic vibration is 5~30µm.
[0014] Furthermore, the ultrasonic vibration is applied in the following manner: The ultrasonic transducer is in direct contact with the back of the bevel; or The ultrasonic transducer is coupled to the bevel sidewall via a clamp; or The ultrasonic transducer and the cold spray nozzle form an integrated vibration coupling structure.
[0015] Furthermore, the gradient transition layer includes a first transition layer, a second transition layer, and a third transition layer arranged sequentially along the steel weld layer away from the weld layer; The first transition layer is a nickel-rich layer or a nickel-iron transition layer. The powder used for cold spraying is nickel powder, nickel-iron mixed powder, or nickel-based alloy powder; the iron content in the nickel-iron mixed powder or nickel-based alloy powder is 5~30 wt%. The second transition layer is an aluminum base layer or an aluminum-nickel composite layer. The powder used for cold spraying is aluminum powder, aluminum-nickel mixed powder, or aluminum-based alloy powder; the nickel content in the aluminum-nickel mixed powder or aluminum-based alloy powder is 5~40 wt%. The third transition layer is a titanium-rich layer or a titanium-aluminum composite layer. The powder used for cold spraying is pure titanium powder, titanium-aluminum mixed powder, or titanium-based alloy powder. The aluminum content in the titanium-aluminum mixed powder or titanium-based alloy powder is 5~30wt%.
[0016] Furthermore, each cold-sprayed layer is applied using continuous spraying or partial overlapping spraying to create a continuous transition interface between the layers. The carrier gas for cold spraying is an inert gas or a mixture of an inert gas and nitrogen; The cold spraying temperature is 200~600℃, the cold spraying pressure is 2~5MPa, and the particle size of the powder used in the cold spraying is 5~50um; The total thickness of the gradient transition layer is 1~2mm.
[0017] Furthermore, the capping welding employs TIG welding, laser welding, or electron beam welding; and / or During the capping welding process, inert gas protection is applied to the titanium weld layer area.
[0018] The beneficial effects of this invention are as follows: This invention pre-constructs a gradient transition layer with continuously varying composition between the steel weld layer and the capping titanium weld layer, forming a stable metallurgical buffer zone before the welding thermal cycle, thereby blocking the direct contact and reaction path between Ti and Fe from the source and achieving controllable adjustment of the interfacial thermo-chemical behavior. The gradient transition layer of this invention preferably adopts a Ti-Al-Ni-Fe compositional gradient system design. Based on the metallurgical characteristic that the Ti-Fe system readily forms high-hardness and brittle intermetallic compounds thermodynamically, Al and Ni are introduced as intermediate transition elements to construct a synergistic mechanism of "diffusion blocking," "reaction regulation," and "stress buffering." Specifically, a Ti-Al transition layer is set on the side closer to the titanium matrix to achieve compositional matching with the titanium matrix and reduce abrupt changes in interface composition. An Al-Ni transition layer is set in the middle and acts as a diffusion regulation layer to block the direct reaction path between Ti and Fe. A Ni-Fe transition layer is set on the side closer to the steel matrix to form a stable solid solution transition zone with the steel matrix, thereby achieving metallurgical compatibility.
[0019] Therefore, this invention can effectively control the reaction path at the titanium-steel interface, thereby significantly suppressing the formation of brittle TiFe phases, reducing residual stress concentration at the interface, and improving the bonding strength, crack resistance, and fatigue life of the welded joint. This ensures reliable connection while fundamentally guaranteeing the joint's toughness and long-term service stability. Attached Figure Description
[0020] The invention will now be described in more detail with reference to embodiments and the accompanying drawings. Figure 1 A schematic diagram of the steps of the present invention is shown; Figure 2 A schematic diagram of the structure after welding of the present invention is shown; In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.
[0021] Figure label: 1. Steel substrate; 2. Titanium substrate; 3. Steel weld layer; 4. Gradient transition layer; 401. First transition layer; 402. Second transition layer; 403. Third transition layer; 5. Titanium weld layer. Detailed Implementation
[0022] The invention will now be further described with reference to the accompanying drawings.
[0023] This invention provides a welding method for titanium-steel composite plates, such as... Figure 1 andFigure 2 As shown, it includes the following steps: Step S1: Process bevels in the areas to be welded on the titanium substrate 2 and the steel substrate 1, and perform surface pretreatment on the bevels; Step S2: Butt welding is performed on the steel substrate 1 to form a continuous and dense steel weld layer 3; Step S3: A gradient transition layer 4 is prepared on the steel weld layer 3 and its adjacent area near the titanium substrate 2 using ultrasonic coupling cold spraying technology. Step S4: Perform capping welding on the titanium substrate 2 to form a titanium weld layer 5 at the end of the gradient transition layer 4 away from the steel weld layer 3.
[0024] Furthermore, in step S1, after the beveling is completed, the beveling surface is mechanically ground and cleaned to remove oil, oxide film and contaminants from the beveling surface, and to control the surface roughness of the beveling within the range of Ra1.6~6.3 or to reach an equivalent sandblasting roughening state, so as to ensure the effective adhesion and bonding of the subsequent gradient transition layer 4.
[0025] Furthermore, in step S2, the butt welding can be carried out using welding processes suitable for steel, such as submerged arc welding, TIG welding, or laser welding, so that the steel weld layer 3 can be fully penetrated and meet the structural load-bearing requirements; in addition, in this step, the titanium matrix 2 does not participate in the molten pool reaction, thereby avoiding the formation of brittle phases due to direct fusion welding of titanium steel.
[0026] Furthermore, in step S3, after the steel weld layer 3 is formed and cooled to room temperature, multiple layers of metal or alloy powders with different compositions are sequentially deposited by cold spraying to form a gradient transition layer 4 with gradually changing composition along the thickness direction. During the cold spraying process, controlled ultrasonic vibration is applied to the spraying deposition area through an ultrasonic transducer to improve the plastic deformation ability of powder particles and the interlayer density.
[0027] Specifically, the frequency of the ultrasonic vibration is 15~40kHz, and the amplitude of the ultrasonic vibration is 5~30um; Each cold spray coating layer is applied using continuous spraying or partial overlapping spraying to create a continuous transition interface between the layers. The carrier gas for cold spraying is an inert gas or a mixture of an inert gas and nitrogen; The cold spraying temperature is 200~600℃, the cold spraying pressure is 2~5MPa, and the particle size of the powder used in the cold spraying is 5~50um; The total thickness of the gradient transition layer 4 is 1~2mm.
[0028] In addition, ultrasonic vibration can be applied in the following ways: The ultrasonic transducer is in direct contact with the back of the bevel. The ultrasonic transducer is coupled to the bevel sidewall via a clamp; The ultrasonic transducer and the cold spray nozzle form an integrated vibration coupling structure.
[0029] Furthermore, the gradient transition layer 4 includes a first transition layer 401, a second transition layer 402, and a third transition layer 403 arranged sequentially along the steel weld layer 3 away from the weld layer 3; The first transition layer 401 is a nickel-rich layer or a nickel-iron transition layer. The powder used for cold spraying is nickel powder, nickel-iron mixed powder, or nickel-based alloy powder; the iron content in the nickel-iron mixed powder or nickel-based alloy powder is 5~30 wt%. The second transition layer 402 is an aluminum base layer or an aluminum-nickel composite layer. The powder used for cold spraying is aluminum powder, aluminum-nickel mixed powder, or aluminum-based alloy powder; the nickel content in the aluminum-nickel mixed powder or aluminum-based alloy powder is 5~40wt%. The third transition layer 403 is a titanium-rich layer or a titanium-aluminum composite layer. The powder used for cold spraying is pure titanium powder, titanium-aluminum mixed powder, or titanium-based alloy powder. The aluminum content in the titanium-aluminum mixed powder or titanium-based alloy powder is 5~30wt%.
[0030] It should be noted that the present invention preferably uses a Ti-Al-Ni-Fe compositional gradient system design, that is, the first transition layer 401 is preferably a nickel-iron transition layer, the second transition layer 402 is preferably an aluminum-nickel composite layer, and the third transition layer 403 is preferably a titanium-aluminum composite layer. Based on this, the design can form a stable solid solution transition region with the steel substrate 1 through the first transition layer 401, thereby achieving metallurgical compatibility; the design uses the second transition layer 402 as a diffusion control layer to block the direct reaction path between Ti and Fe; and the design uses the third transition layer 403 to achieve compositional matching with the titanium substrate 2 and reduce abrupt changes in interface composition.
[0031] It should also be noted that the gradient transition layer 4 of the present invention is not limited to a three-layer structure, but can also be configured as a transition layer with two or more layers of gradually changing components.
[0032] Furthermore, in step S4, the capping welding is performed using TIG welding, laser welding, or electron beam welding, and inert gas protection is applied to the area of the titanium weld layer 5 during the capping welding process; in addition, the welding heat input is strictly controlled to prevent the molten pool from penetrating the gradient transition layer 4 and reacting directly with the steel substrate 1.
[0033] Two examples and two comparative examples are given below.
[0034] Example 1 For the test specimens and materials, this embodiment selects a 6mm thick TA2 titanium plate and an 8mm thick Q235A steel plate as the base material for butt welding. The two plates are processed into rectangular plates with a size of 100mm×50mm, and the two plates are butt-welded with an X-shaped bevel angle of 60°.
[0035] For beveling pretreatment, in this embodiment, the bevel surfaces of TA2 titanium plate and Q235A steel plate are mechanically polished with 120-mesh sandpaper to remove the surface oxide layer; then the surfaces to be welded are ultrasonically cleaned in acetone or anhydrous ethanol for 10 minutes; after cleaning, they are air-dried for later use.
[0036] For the butt welding of the steel substrate 1, this embodiment performs butt welding on one side of the Q235A steel plate; TIG welding is used for multi-layer and multi-pass welding to ensure that the steel weld layer 3 is fully penetrated and forms a continuous and dense weld structure, and the TA2 titanium plate does not participate in the molten pool reaction, thereby avoiding the direct fusion of Ti-Fe to form brittle intermetallic compounds; after welding, air cooling to room temperature is performed.
[0037] For the arrangement of the ultrasonic coupling cold spraying device, in this embodiment, a gradient transition layer 4 is prepared in the steel weld layer 3 and its adjacent area; the preparation process uses an industrial ultrasonic transducer, and the ultrasonic frequency is set to 20kHz; the ultrasonic transducer contacts the back of the steel substrate 1 through a rigid clamp so that the vibration is transmitted to the spraying deposition area along the thickness direction; the ultrasonic vibration is continuously applied throughout the cold spraying process.
[0038] For the cold spraying preparation of the gradient transition layer 4, the following cold spraying process parameters are used in this embodiment: the carrier gas is nitrogen, the cold spraying gas temperature is 350℃, the cold spraying gas pressure is 3.5MPa, the cold spraying distance is 20mm, and the particle size of the powder used for cold spraying is 10~30um. This embodiment employs the following gradient transition layer 4 structure and powder system: a first transition layer 401, a second transition layer 402, and a third transition layer 403 are sequentially deposited on the surface of the steel weld layer 3. The powder used for cold spraying the first transition layer 401 is a nickel-iron mixed powder with an iron mass fraction of 15 wt%, and the thickness of the first transition layer 401 is approximately 0.5 mm. The powder used for cold spraying the second transition layer 402 is an aluminum-nickel mixed powder with a nickel mass fraction of 20 wt%, and the thickness of the second transition layer 402 is approximately 0.5 mm. The powder used for cold spraying the third transition layer 403 is a titanium-aluminum mixed powder with an aluminum mass fraction of 10 wt%, and the thickness of the third transition layer 403 is approximately 0.4 mm. Through multi-layer ultrasonic cold spraying, a gradient transition layer 4 with a thickness of approximately 1.4 mm is formed, thereby completing the gradient transition of the titanium-steel weld from steel to NiFe to AlNi to TiAl to titanium.
[0039] For the capping welding of the titanium substrate 2, this embodiment uses TIG welding to fill the titanium side bevel. High-purity argon gas protection is implemented during the welding process. The welding heat input is controlled so that the molten pool only acts on the titanium substrate 2 and the upper region of the gradient transition layer 4, avoiding penetration into the steel substrate 1. After welding, it is allowed to cool naturally.
[0040] Macroscopic and microscopic observations of the joint after welding in this embodiment show that: The titanium-steel interface is continuous and intact, and no obvious interface delamination was observed. The tensile strength of the joint is increased by 15% to 30%; No brittle fracture at the interface occurred during the bending test; No through-interface cracks were observed after welding.
[0041] Example 2 For the selection of the base material, this embodiment selects a 6mm thick Ti-6Al-4V titanium alloy plate and an 8mm thick 304 austenitic stainless steel plate as the welding base material and adopts butt welding. Since 304 stainless steel contains about 8-10 wt% Ni and 18 wt% Cr, its alloying elements can alleviate the direct reaction activity between Fe and Ti to a certain extent, and the interface reaction sensitivity is relatively lower than that of pure carbon steel system.
[0042] For beveling and surface pretreatment, the beveling form and surface roughness control method in this embodiment are the same as in embodiment 1.
[0043] For the preparation of the ultrasonic cold spray double transition layer, in this embodiment, 20KHz ultrasonic vibration is applied to the surface of the steel weld layer 3, and the rest of the ultrasonic vibration arrangement is the same as in Example 1; in addition, based on the characteristic of the low degree of interfacial reaction of the 304 stainless steel material system, a double gradient transition structure is formed by cold spraying on the bevel surface of the titanium substrate 2 in sequence. Specifically, the powder used for the first cold spray coating near the steel substrate 1 is a nickel-iron mixed powder with an iron mass fraction of 15 wt%, and the thickness of the first layer is about 0.7 mm. The powder used for the second cold spray coating near the titanium substrate 2 is a titanium-aluminum mixed powder with an aluminum mass fraction of 20 wt%, and the thickness of the second layer is about 0.7 mm, so as to form a double-layer gradient transition structure with a thickness of about 1.2 mm, thereby completing the gradient transition of the titanium-steel weld from steel to NiFe to TiAl to titanium.
[0044] Regarding the welding steps, in this embodiment, the welding of the steel substrate 1 side is completed first, and then the sealing welding of the titanium substrate 2 side is performed. The welding pool mainly acts on the transition layer area, so that the titanium and steel form an interface connection after gradient control.
[0045] Observation of the interface after welding in this embodiment shows that: In the Ti-6Al-4V titanium alloy and 304 stainless steel material system, the formation of a continuous brittle Ti-Fe reaction layer can be effectively avoided by adopting a double-layer gradient transition structure. The interface structure is continuous and no obvious cracking is observed. This shows that in material systems with low interface reaction sensitivity, an economical structural design can be achieved by reducing the number of gradient layers.
[0046] Comparative Example 1 The comparative example uses the same TA2 titanium plate and Q235A steel plate as Example 1, but does not perform cold spraying gradient transition layer 4 preparation, and directly performs bevel butt welding, and the welding method is the same as in Example 1.
[0047] The results observed after welding of the comparative example are as follows: The titanium-steel interface continuously forms an intermetallic compound layer without diffusion barriers or stress buffer regions. The thickness of the brittle intermetallic compound layer in Example 1 was significantly higher than that in Example 1, with TiFe and TiFe2 phases dominating the interface. Compared with Comparative Example 1, the thickness of the intermetallic compound layer in Example 1 was reduced by 30% to 50%. Brittle fracture of the interface was observed during the joint bending test; The tensile strength of the joint is reduced by more than 20% compared with Example 1, and its fatigue resistance is poor.
[0048] Comparative Example 2 The comparative example follows the process steps of Example 1, but does not apply ultrasonic vibration during cold spraying to form a gradient transition layer 4 with the same thickness and composition structure; the welding steps are the same as in Example 1.
[0049] The results observed after welding of the comparative example are as follows: The gradient transition layer 4 has obvious pores and discontinuous interlayer bonding. Insufficient interlayer bonding strength fails to adequately block the direct reaction pathway of Ti–Fe; The tensile strength of the joint is reduced by 10% to 25% compared to Example 1; Microcracks appear locally after welding thermal cycling, reducing fatigue performance.
[0050] In summary, the present invention can form a stable metallurgical buffer zone by pre-constructing a gradient transition layer 4 with continuously changing composition between the steel weld layer 3 and the capping titanium weld layer 5, thereby blocking the direct contact and reaction path between Ti and Fe from the source and achieving controllable adjustment of the interfacial thermo-chemical behavior. The gradient transition layer 4 of the present invention preferably adopts a Ti-Al-Ni-Fe compositional gradient system design. Based on the metallurgical characteristics of the Ti-Fe system, which is thermodynamically prone to forming high-hardness and brittle intermetallic compounds, Al and Ni are introduced as intermediate transition elements to construct a synergistic mechanism of "diffusion blocking", "reaction regulation" and "stress buffering". Specifically, a Ti-Al transition layer is set on the side closer to the titanium substrate 2 to achieve compositional matching with the titanium substrate 2 and reduce abrupt changes in interface composition. An Al-Ni transition layer is set in the middle and acts as a diffusion regulation layer to block the direct reaction path between Ti and Fe. A Ni-Fe transition layer is set on the side closer to the steel substrate 1 to form a stable solid solution transition zone with the steel substrate 1, thereby achieving metallurgical compatibility.
[0051] Therefore, this invention can effectively control the reaction path at the titanium-steel interface, thereby significantly suppressing the formation of brittle TiFe phases, reducing residual stress concentration at the interface, and improving the bonding strength, crack resistance, and fatigue life of the welded joint. This ensures reliable connection while fundamentally guaranteeing the joint's toughness and long-term service stability.
[0052] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and 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. Therefore, they should not be construed as limitations on this invention.
[0053] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.
Claims
1. A welding method for titanium-steel composite plates, characterized in that, It includes the following steps: Bevels are machined in the areas to be welded in the titanium substrate (2) and the steel substrate (1), and the bevels are pre-treated. The steel substrate (1) is butt welded to form a continuous and dense steel weld layer (3). A gradient transition layer (4) is prepared on the steel weld layer (3) and its adjacent area near the titanium substrate (2) using ultrasonic coupling cold spraying technology. The titanium substrate (2) is capped by welding to form a titanium weld layer (5) at the end of the gradient transition layer (4) away from the steel weld layer (3).
2. The welding method for titanium-steel composite plates according to claim 1, characterized in that, The surface pretreatment of the bevel includes: After the beveling process is completed, the beveling surface is mechanically ground and cleaned to remove oil, oxide film and contaminants, and to control the surface roughness of the beveling within the range of Ra1.6~6.3 or to achieve an equivalent sandblasting roughening state.
3. The welding method for titanium-steel composite plates according to claim 1, characterized in that, Butt welding is performed using submerged arc welding, TIG welding, or laser welding; and / or During the butt welding process, the titanium matrix (2) does not participate in the molten pool reaction.
4. The welding method for titanium-steel composite plates according to claim 1, characterized in that, The preparation of the gradient transition layer (4) using ultrasonic coupling cold spraying technology includes: After the steel weld layer (3) cools to room temperature, a gradient transition layer (4) is prepared.
5. A welding method for titanium-steel composite plates according to claim 1 or 4, characterized in that, The preparation of the gradient transition layer (4) using ultrasonic coupling cold spraying technology includes: Multiple layers of metal or alloy powders with different compositions are sequentially deposited by cold spraying to form a gradient transition layer (4) with gradually changing composition along the thickness direction. During the cold spraying process, controlled ultrasonic vibration is applied to the spraying deposition area by an ultrasonic transducer.
6. The welding method for titanium-steel composite plates according to claim 5, characterized in that, The frequency of ultrasonic vibration is 15~40kHz, and the amplitude of ultrasonic vibration is 5~30um.
7. A welding method for titanium-steel composite plates according to claim 5, characterized in that, The ultrasonic vibration is applied in the following way: The ultrasonic transducer is in direct contact with the back of the bevel; or The ultrasonic transducer is coupled to the bevel sidewall via a clamp; or The ultrasonic transducer and the cold spray nozzle form an integrated vibration coupling structure.
8. The welding method for titanium-steel composite plates according to claim 5, characterized in that, The gradient transition layer (4) includes a first transition layer (401), a second transition layer (402) and a third transition layer (403) arranged sequentially along the steel weld layer (3). The first transition layer (401) is a nickel-rich layer or a nickel-iron transition layer. The powder used for cold spraying is nickel powder, nickel-iron mixed powder, or nickel-based alloy powder. The iron content in the nickel-iron mixed powder or nickel-based alloy powder is 5~30 wt%. The second transition layer (402) is an aluminum base layer or an aluminum-nickel composite layer. The powder used for cold spraying is aluminum powder, aluminum-nickel mixed powder, or aluminum-based alloy powder. The nickel content in the aluminum-nickel mixed powder or aluminum-based alloy powder is 5~40wt%. The third transition layer (403) is a titanium-rich layer or a titanium-aluminum composite layer. The powder used for cold spraying is pure titanium powder, titanium-aluminum mixed powder or titanium-based alloy powder. The aluminum content in the titanium-aluminum mixed powder or titanium-based alloy powder is 5~30wt%.
9. A welding method for titanium-steel composite plates according to claim 5, characterized in that, Each cold spray coating layer is applied using continuous spraying or partial overlapping spraying to create a continuous transition interface between the layers. The carrier gas for cold spraying is an inert gas or a mixture of an inert gas and nitrogen; The cold spraying temperature is 200~600℃, the cold spraying pressure is 2~5MPa, and the particle size of the powder used in the cold spraying is 5~50um; The total thickness of the gradient transition layer (4) is 1~2mm.
10. The welding method for titanium-steel composite plates according to claim 1, characterized in that, The capping welding is performed using TIG welding, laser welding, or electron beam welding; and / or During the capping welding process, inert gas protection is applied to the titanium weld layer (5) area.