CN103551721B - Ultrasonic prefabricated transitional band welds the method preparing heterogenous material joint subsequently - Google Patents

Abstract

The invention discloses a method for preparing a joint of dissimilar materials by ultrasonically prefabricating a transition zone followed by welding. The main content is as follows: at least one layer of metal foil is stacked on the surface of the material to be connected by ultrasonic rolling welding to form a stacked layer. After the stacked layer is prepared, the milling cutter of the ultrasonic rolling welding system is used to cut off the unconnected part of the surrounding foil, and then the stacked layer is milled to form a transition zone of suitable shape and size. Then the transition zone is directly welded with another metal to be connected by welding, brazing or diffusion welding, so as to obtain a macroscopic structure of the material to be connected-transition zone-weld-another material to be connected Dissimilar material joints. The technical solution of the present invention utilizes the advantages of ultrasonic solid-phase connection to finally establish a transition zone by stacking metal foils on the surface of the materials to be connected, and indirectly converts the welding of dissimilar refractory materials into the welding of two types of materials with metallurgical compatibility. A dissimilar material joint with reliable performance is prepared.

Description

Method for preparing joints of dissimilar materials by ultrasonically prefabricating a transition zone followed by welding

technical field

The invention belongs to the field of welding connection of dissimilar materials, and mainly relates to a process method for preparing joints of dissimilar materials by ultrasonic rolling welding of prefabricated transition zones, especially the advantages of good joint strength and low material type dependence obtained by ultrasonic rolling welding. Before the material is directly welded, the transition zone is prefabricated on the surface of the material to be connected by means of ultrasonic solid-phase bonding, and the direct welding between dissimilar materials is transformed into a new process method of welding between metallurgically tolerant materials.

Background technique

Since dissimilar material joints can combine the performance advantages of two metals, they are more and more widely used in the industrial field, for example, aluminum/steel dissimilar material joints, aluminum/copper dissimilar material joints, etc. At present, fusion welding and solid-phase welding methods are mostly used in the welding of dissimilar materials, such as electron beam welding, MIG welding, TIG welding, etc., which have been tried in the production of dissimilar material joints. However, when welding dissimilar materials, a large number of brittle compounds are likely to be produced in the weld when the atoms of some material groups are in contact with each other in the liquid or solid phase, which greatly deteriorates the performance of the joint.

Taking fusion welding as an example, although fusion welding of dissimilar metals is a relatively economical and practical method at present, it is flexible and has various welding methods, which can be applied to different welding situations. However, when the joints of dissimilar materials are simply welded by fusion welding, hard and brittle intermetallic compounds are often produced at the weld. Compounds, even if the static mechanical properties of the joints are guaranteed by optimizing the welding process, the dynamic mechanical properties of the joints in practical applications will be greatly reduced due to the existence of these brittle compound phases.

In the research and practice of welding dissimilar materials, the inventors of the present invention have found that the transition zone can be prefabricated on the surface of one of the materials to be joined by stacking metal foil layers by means of ultrasonic roll welding, and then the The transition zone and another material to be joined are directly welded together by fusion welding, brazing or diffusion welding, and the transition zone is used as an intermediate connection medium to form a multi-region transition joint to avoid the appearance of brittle intermetallic compound phases.

Contents of the invention

The purpose of the present invention is to solve the problem that the direct metallurgical reaction of the two materials will form a large number of brittle intermetallic compounds in the joint area during the direct welding preparation of the joints of dissimilar materials, which will reduce the performance of the joints. A method of ultrasonic prefabricated transition zone followed by welding to prepare dissimilar material joints is proposed with low cost, good joint performance and wide applicability to various materials.

The present invention can be achieved through the following technical solutions.

A method for ultrasonically prefabricating a transition zone followed by welding to prepare a joint of dissimilar materials, characterized in that the steps are as follows:

Step 1, cleaning the surface of the material, using sandpaper or grinding wheel to polish the connection surface of the material to be connected on which the transition zone needs to be prepared;

Step 2, metal foil clamping, place at least one layer of metal foil on the surface of the above-mentioned polished materials to be connected, and use clamps to clamp the metal foil and the connection surface of the materials to be connected, so that the metal foil and the materials to be connected are connected Close surface contact;

Step 3. Prepare the stacked layer, apply pressure and vibration to the metal foil by using the ultrasonic roll welding system, and roll weld the metal foil on the connection surface of the material to be connected or the previous layer of metal foil that has been connected to the connection surface of the material to be connected , forming a metal foil stack layer;

Step 4. Prepare the transition zone. The ultrasonic rolling welding system comes with a three-dimensionally movable milling cutter to cut off the unconnected area of the stacked layer, and mill the stacked layer according to the size of the surface to be connected of another material to be connected. For the excess part, obtain a transition zone whose shape and size meet the requirements;

Step five, final welding, the transition zone and another material to be connected are welded together by direct welding.

The metal foil stacked layer of the present invention can be prepared from one layer of metal foil, or can be formed from two or more layers of metal foil through multiple times of ultrasonic rolling welding, so as to meet the technical requirements of different material structures.

The metal foil of the present invention can be a material close to or even the same as another material to be connected on which no transition zone is prefabricated in chemical composition, or it can have better metallurgical compatibility with another material to be connected. It is a material that does not react with it to form brittle intermetallic compounds in subsequent welding.

The stacked layer in the present invention can be formed by stacking metal foils of a single metal material, or can be obtained by stacking metal foils of two or more metal materials with better solid-phase connectivity.

The thickness of the metal foil described in the present invention is generally not greater than 1mm, and has a width that can be welded by ultrasonic rolling at least 3mm, so that the size of the stacked layer obtained by rolling and stacking is large enough to meet the subsequent welding requirements.

The direct welding method described in the present invention includes fusion welding or brazing or diffusion welding.

The pressure, power and frequency of the ultrasonic rolling welding system of the present invention can be adjusted, the maximum pressure can reach 1000N, the power is below 5000W, and the vibration frequency is 10kHz-75kHz.

In the ultrasonic rolling welding system of the present invention, the pressure of the rollers is adjusted through hydraulic control, and the pressure can be displayed in real time, so that the stacking process of metal foils can be easily realized. At the same time, there is a milling device behind the roller, which can realize the subsequent mechanical processing of the stacked layers.

The indenter of the ultrasonic rolling welding system according to the present invention is a replaceable roller. The surface of the roller can be a smooth surface or a different cross-textured surface. The material and surface pattern of the roller should be selected according to the different stacking materials. .

In the present invention, the transition zone is prefabricated by ultrasonic rolling welding between two materials to be connected, so it can avoid a large number of brittle compounds formed when dissimilar materials, especially dissimilar materials with poor metallurgical compatibility, are directly welded. The macroscopic structure of the material joint presents the characteristics of the material to be connected-metal transition zone-weld-another material to be connected, which reduces or even avoids the generation of brittle intermetallic compounds in the joint of dissimilar materials, ensuring that the joint of dissimilar materials has excellent Mechanical properties and performance, even if the physical properties of the materials are very different, they can be welded well.

The ultrasonic rolling welding applied in the present invention generally adopts a frequency of 15kHz to 75kHz. Although ultrasonic rolling welding can only be applied to thinner metal materials, its welding speed is fast and continuous welding can be realized. In the present invention, a transition zone made of stacked metal foils is prepared on the material surface by means of ultrasonic rolling welding. Especially convenient. At the same time, ultrasonic rolling welding has high strength, good stability, and small deformation of the workpiece. It does not need to be energized during the welding process. When sufficient energy is applied, local overheating will occur, and the metal will be frictionally bonded. The stacked metal foil and There is no melting reaction between the materials to be connected, and the solid phase or semi-solid phase connection is formed only by atomic diffusion. Therefore, using this method to prefabricate the transition zone on the surface of the materials to be connected can avoid the generation of brittle and hard intermetallic compounds. Moreover, the ultrasonic rolling welding equipment is relatively simple, and the ultrasonic generating device is easy to control, which can be well controlled and cooperate with the computer, which is beneficial to automatic production.

At the same time, the ultrasonic prefabrication transition zone provided by the present invention has simple method, controllable prefabrication parameters and flexible multi-dimensional processing, and can perform arbitrary ultrasonic rolling prefabrication according to the required joint form of dissimilar materials. After roll prefabrication, a simple machining of the stacked layers creates a transition strip that can be subsequently welded. Various welding methods can then be used to effectively weld the transition strip to another material to be joined. Therefore, in terms of the production cost of dissimilar material joints, the present invention can avoid process exploration and related process auxiliary means for direct welding of dissimilar materials. The fixture can realize the prefabrication process of the transition zone very easily. In combination with the above points, it can be seen that the method for preparing the joint of dissimilar materials by ultrasonically prefabricating the transition zone and then welding provided by the present invention has typical characteristics of low cost, and finally realizes two High-quality and reliable solder joints between materials, especially difficult-to-solder materials.

Description of drawings

Fig. 1 is the schematic diagram of the ultrasonic rolling welding system adopted in this method.

Fig. 2 is a schematic diagram of a dissimilar material joint made by this method.

Fig. 3 is a schematic diagram of the process of welding with fusion welding in this method.

Fig. 4 is a schematic diagram of the welding process using the diffusion welding method in this method.

detailed description

As shown in Figure 1 and Figure 2, the method for preparing the joint of dissimilar materials by ultrasonic rolling prefabricated transition zone followed by welding includes the following steps: firstly, the surface to be connected of the material (1) to be connected is cleaned by grinding with sandpaper or grinding wheel, On the surface of the material to be joined (1), use the roller pressure head (7) of the ultrasonic rolling welding system to weld one or more layers of metal foil (2) on the surface of (1) to obtain a stacked layer (3); then use the system The built-in milling cutter (8) processes the shape and size of the stacked layer (3) by mechanical processing to obtain a transition zone (4) of a certain shape and size for subsequent welding; finally, fusion welding, brazing or diffusion welding is used The welding method directly welds the transition zone (4) and another material (6) to be connected to form a weld (5), and finally obtains a dissimilar material joint between the material (1) and the material (6).

Example 1

Adopt the present invention as shown in Figure 3, use 0.2mm thick aluminum foil on the 1mm thick copper plate (9) by ultrasonic rolling, stack and weld 7 layers of aluminum foil on the surface of the copper plate (9) in sequence, forming a width of about 5mm Wide stacking layer, then machine the three sides of the stacking layer with the milling cutter that comes with the system to form a boss-shaped transition zone (10) made of aluminum foil with a height of 1mm and a width of 4mm, and then cut the 1mm thick The aluminum plate (12) and the transition zone (10) are flat-butt assembled, and finally the gas metal shielded welding torch (13) is used for welding with aluminum wire to form a weld (11) to realize the dissimilarity between the copper plate (9) and the aluminum plate (12) material connection. Tensile tests were carried out after welding, and the joints were all broken at the fusion welding seam, and the strength was far greater than that obtained by direct fusion welding of copper and aluminum with a fusion welding torch.

Example 2

Adopt the present invention as shown in Figure 4, use 0.2mm thick aluminum foil on the 4mm thick steel plate (14) by ultrasonic roll welding, stack and weld 7 layers of aluminum foil on the surface of the steel plate (14) in sequence, forming a width of about 5mm wide stacked layer, and then use a milling cutter to machine the three sides of the stacked layer to form a boss-shaped transition zone (15) with a height of 1mm and a width of 4mm, which is composed of aluminum foil stacked interconnections, and then the 4mm thick The aluminum plate (16) and the transition zone (15) are vertically docked and assembled, then put into a vacuum furnace, and the transition zone (15) and the aluminum plate (16) are welded by means of diffusion welding. After welding, the shear test is carried out. Since the transition reaction caused by the contact between the aluminum plate (16) and the steel plate (14) is avoided by diffusion welding, the amount of intermetallic compounds is reduced, and the strength of the joint is greatly improved.

Claims (9)

1. A method for ultrasonically prefabricated transition zone welding to prepare dissimilar material joints, characterized in that the steps are as follows: Step 1, cleaning the surface of the material, using sandpaper or grinding wheel to polish the connection surface of the material to be connected on which the transition zone needs to be prepared; Step 2, metal foil clamping, place one or more layers of metal foil on the surface of the material to be connected after grinding, and use clamps to clamp the metal foil and the connection surface of the material to be connected, so that the metal foil and the material to be connected The connecting surfaces of the connecting materials are in close contact; Step 3. Prepare the stacked layer, apply pressure and vibration to the metal foil by using the ultrasonic roll welding system, and roll weld the metal foil on the connection surface of the material to be connected or the previous layer of metal foil that has been connected to the connection surface of the material to be connected , forming a metal foil stack layer; Step 4. Prepare the transition zone. The ultrasonic rolling welding system comes with a three-dimensionally movable milling cutter to cut off the unconnected area of the stacked layer, and mill the stacked layer according to the size of the surface to be connected of another material to be connected. For the excess part, obtain a transition zone whose shape and size meet the requirements; Step five, final welding, the transition zone and another material to be connected are welded together by direct welding. 2. A method of ultrasonic prefabricated transition zone followed by welding to prepare dissimilar material joints according to claim 1, characterized in that the chemical composition of the metal foil is close to that of another material to be connected that is not prefabricated on the transition zone Or the same material or have better metallurgical compatibility with another material to be joined, that is, a material that does not react with it to form brittle intermetallic compounds in subsequent welding. 3. A method of ultrasonic prefabricated transition zone followed by welding to prepare dissimilar material joints according to claim 1, characterized in that the stacked layers are stacked of metal foils of a single metal material or made of two or more metal foils with relatively Metal foil stacks of metallic materials with good solid phase connectivity are obtained. 4. A method for preparing a joint of dissimilar materials by ultrasonic prefabricated transition zone followed by welding according to claim 1, characterized in that the thickness of the metal foil is not greater than 1 mm, and the width of the ultrasonic roll welding is not less than 3 mm. 5. A method for preparing a joint of dissimilar materials by ultrasonic prefabricated transition zone followed by welding according to claim 1, characterized in that the direct welding method includes fusion welding, brazing or diffusion welding. 6. A method for preparing a joint of dissimilar materials by ultrasonic prefabricated transition zone according to claim 1, characterized in that the pressure, power and frequency of the ultrasonic rolling welding system are all adjustable, the maximum pressure is 1000N, and the power is below 5000W , the vibration frequency is 10kHz-75kHz. 7. A method for ultrasonic prefabricated transition zone followed by welding to prepare dissimilar material joints according to claim 1, characterized in that the pressure of the rollers in the ultrasonic rolling welding system is adjusted by hydraulic control, and the pressure can be displayed in real time. 8. A method for preparing a joint of dissimilar materials by ultrasonic prefabricated transition zone followed by welding according to claim 1, characterized in that the ultrasonic rolling welding system is provided with a milling device capable of performing subsequent mechanical processing on stacked layers. 9. A method of ultrasonic prefabricated transition zone followed by welding to prepare dissimilar material joints according to claim 1, characterized in that the indenter in the ultrasonic rolling welding system is a replaceable roller, and the surface of the roller is a smooth surface or Cross textured surface.