CN116275646A

CN116275646A - Aluminum alloy connecting method

Info

Publication number: CN116275646A
Application number: CN202310228125.9A
Authority: CN
Inventors: 陈勇
Original assignee: Shenzhen Envicool Technology Co Ltd
Current assignee: Shenzhen Envicool Technology Co Ltd
Priority date: 2023-02-28
Filing date: 2023-02-28
Publication date: 2023-06-23

Abstract

The invention provides a connecting method of aluminum alloy, which comprises the following steps: providing a stacked structure, the stacked structure comprising: a first metal base material, a second metal base material, and zinc-containing metal disposed between the first metal base material and the second metal base material; the first metal base material is selected from aluminum alloy; and welding the stacked structure. The heating temperature in the invention is 400-600 ℃, the pure zinc sheet or the zinc alloy sheet is used as the intermediate connection alloy, and the material is easy to obtain and the cost is low from the viewpoint of raw materials. The melting point of pure zinc in the invention is about 419 ℃, and the zinc and aluminum elements are in a temperature range of 400-600 ℃ as shown by a zinc-aluminum binary alloy phase diagram, so that 97.2% of zinc elements can be melted on an aluminum matrix at maximum, and pure zinc sheets or zinc and alloy sheets thereof are used as welding connection metals, thereby not only ensuring that aluminum alloy is connected at 400-600 ℃ efficiently, but also ensuring that the performance of aluminum alloy base metal is not deteriorated.

Description

Aluminum alloy connecting method

Technical Field

The invention belongs to the technical field of aluminum alloy, and particularly relates to a connecting method of aluminum alloy.

Background

Aluminum and its alloy have light weight, high strength, excellent corrosion resistance, strong appearance performance after surface treatment, etc., so that it is widely used in various links of industrial production. The research on the connection process between aluminum alloys is an important subject research direction, and common aluminum alloy connection modes are as follows: fusion welding, brazing, argon arc welding, friction stir welding, and the like.

The brazing connection of aluminum alloy is usually performed by adopting a brazing mode, wherein the brazing refers to the welding temperature is more than 450 ℃, a soldering paste is coated on a connecting surface of metal or a soldering lug is placed on the connecting surface of metal, a heat source is provided by a heating mode to enable the intermediate solder to be molten, and physical and chemical reactions occur on the connecting surface, so that the brazing connection of aluminum alloy is realized, and the heating mode comprises but is not limited to flame heating, resistance heating and the like.

The welding material for aluminum alloy connection in the prior art mainly uses aluminum as a matrix, contains a certain amount of silicon element and aluminum-silicon solder composed of a small amount of other elements, for example, 4043, 4047, 4747 and other aluminum-silicon alloys, and has various state forms such as paste, sheet, wire and the like. Aluminum and silicon elements start to undergo eutectic reaction at 577 ℃ (eutectic reaction means a reaction that liquid with a certain component simultaneously crystallizes into solid phases with two certain components at a certain temperature, the two generated solid phases are mechanically mixed together to form a basic structure with fixed chemical components, which is called as eutectic, three phases coexist when eutectic reaction occurs, the respective components are definite, the reaction is carried out in balance at a constant temperature), aluminum-silicon solder starts to melt at a temperature higher than 577 ℃, and the aluminum-silicon solder gradually changes from solid to liquid with the increase of the temperature, so that the aluminum-silicon solder has good wettability and fluidity and is widely used.

However, the aluminum-silicon solder has a limitation in that, in order to achieve the reliability of an aluminum alloy welded joint (joint where two or more parts are to be joined by welding; or joint where two or more parts are to be joined by welding, including a weld, a fusion zone and a heat affected zone), the aluminum-silicon solder must be sufficiently melted to secure its wettability and fluidity, and thus the welding temperature must be 30 to 50 c higher than the melting point (solidus temperature) of the aluminum-silicon solder. Welding at 580 ℃ and above, which exceeds the recrystallization temperature of the aluminum alloy (the minimum temperature at which the recrystallization process can be completed in 1 hour of the heat-retaining time for a metal subjected to large cold plastic deformation (70% or more), called the recrystallization temperature) and the solidus temperature of most aluminum alloys, causes deterioration of the base material properties. Although some aluminum alloys can improve material properties through subsequent heat treatment, the aluminum alloys belong to heat-treatable reinforced aluminum alloys, but most aluminum alloy materials are annealed and softened locally or wholly after welding and cannot be heat-treated and reinforced, and the aluminum alloys belong to non-heat-treatable reinforced aluminum alloys.

Therefore, in the existing aluminum alloy brazing process, a brazing connection mode is sought below the solidus temperature of most aluminum alloys, and the reliability of a welded joint is particularly important, so that not only can the effective connection of aluminum alloy materials be realized, but also the comprehensive performance of the aluminum alloy materials can be ensured not to be lost.

Disclosure of Invention

In view of the above, the present invention aims to provide a welding connection method for aluminum alloy, which can weld aluminum alloy at a temperature lower than solidus temperature and even lower than recrystallization temperature, thereby obtaining good welding quality.

The invention provides a connecting method of aluminum alloy, which comprises the following steps:

providing a stacked structure, the stacked structure comprising: a first metal base material, a second metal base material, and zinc-containing metal disposed between the first metal base material and the second metal base material; the first metal base material is selected from aluminum alloy;

and welding the stacked structure.

Preferably, the mass content of zinc in the zinc-containing metal is more than or equal to 70%.

Preferably, the zinc-containing metal is selected from pure zinc metal and/or zinc alloy.

Preferably, the zinc-containing metal has a thickness of 0.01 to 2mm.

According to the invention, good interface element fusion can be obtained by adopting a specific zinc-containing metal thickness, if the thickness is too thin, the connection effect cannot be achieved, and if the thickness is too thick, uneven heat transfer can be caused, so that the interface element fusion is insufficient.

Preferably, the temperature of the welding is 400-600 ℃.

Preferably, the welding time is 3-7 min.

The special welding time is adopted in the invention, so that the element diffusion and fusion can happen to the connecting interface, and if the welding time is too short, the intermediate alloy is insufficiently melted, and the connecting effect can not be achieved; if the welding time is too long, the base metal will melt into the intermediate alloy layer to cause melting corrosion.

Preferably, the welding is performed under inert atmosphere and/or vacuum conditions.

Preferably, a weight is placed on the stacked structure during the welding process;

the weight of the weight is 0.1-10 kg.

According to the invention, the weight is pressed and placed in the welding process, a certain force can be applied to the intermediate alloy layer, so that the intermediate alloy and the base metal alloys at two sides are tightly attached in the welding process, and even if the intermediate alloy is affected by temperature, the intermediate alloy becomes soft and collapses, the intermediate alloy can be well attached to the base metal alloys at two sides, and the welding effect can be improved.

Preferably, the method further comprises:

cleaning the first metal base material and the second metal base material;

the cleaning is firstly cleaning by adopting an alkali solution and then cleaning by adopting an acid solution.

According to the invention, through acid-base cleaning of the surface of the metal base metal, grease and oxide films can be removed, and the surface activity of the aluminum alloy can be improved, so that the welded joint has better quality.

Preferably, the first metal base material is selected from one or more of a 1-series aluminum alloy, a 3-series aluminum alloy and a 6-series aluminum alloy;

the second metal base material is selected from one or more of aluminum alloy, copper alloy and steel.

The present invention provides a way of joining (welding) two or more aluminium alloy materials, including but not limited to aluminium alloys and aluminium alloys, but also aluminium alloys and copper alloys, aluminium alloys and steel. In order to solve the technical contradiction point of aluminum alloy welding, the key of the invention is that the welding temperature is controlled not to exceed the recrystallization temperature of the aluminum alloy at first and is far away from the solidus temperature (overburning temperature) of the aluminum alloy material; secondly, the welding time is controlled, so that the welding process of short-time high efficiency ensures the performance of the welding joint.

The invention takes common aluminum alloy brands in the market as parent materials and takes pure zinc sheets or zinc alloy sheets as intermediate connecting alloys, adopts a laminated structure form, and heats the aluminum alloy parent materials at two sides in the vacuum or inert atmosphere environment so as to connect the aluminum alloy parent materials. The heating temperature in the invention is 400-600 ℃, the pure zinc sheet or the zinc alloy sheet is used as the intermediate connection alloy, and the material is easy to obtain and the cost is low from the viewpoint of raw materials. The melting point of pure zinc in the invention is about 419 ℃, and the zinc and aluminum elements are in a temperature range of 400-600 ℃ as shown by a zinc-aluminum binary alloy phase diagram, so that 97.2% of zinc elements can be melted on an aluminum matrix at maximum, and pure zinc sheets or zinc and alloy sheets thereof are used as welding connection metals, thereby not only ensuring that aluminum alloy is connected at 400-600 ℃ efficiently, but also ensuring that the performance of aluminum alloy base metal is not deteriorated.

Drawings

FIG. 1 is a schematic diagram of a stacked structure according to an embodiment of the present invention;

FIG. 2 is a metallographic structure diagram of a welded joint after welding in example 1 of the present invention;

FIG. 3 is a metallographic structure diagram of a welded joint according to example 2 of the present invention;

FIG. 4 is a metallographic structure diagram of a welded joint after welding in example 3 of the present invention;

fig. 5 is a metallographic structure diagram of a welded joint after welding in example 4 of the present invention.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

and welding the stacked structure.

In the present invention, the stacked structure includes three layers, a first layer is a first metal base material, a third layer is a second metal base material, and a second layer is zinc-containing metal, as shown in fig. 1.

In the present invention, the first metal base material is preferably an aluminum alloy, and more preferably selected from a 1-series aluminum alloy, a 3-series aluminum alloy, a 6-series aluminum alloy, and the like, such as an aluminum alloy with the designation 1100, an aluminum alloy with the designation 3003, and an aluminum alloy with the designation 6063.

In the present invention, the second metal base material is preferably selected from one or more of aluminum alloy, copper alloy and steel, more preferably selected from aluminum alloy, most preferably selected from 1-series aluminum alloy, 3-series aluminum alloy, 6-series aluminum alloy, etc., such as aluminum alloy with the designation 1100,

aluminum alloy

3003, 6063 aluminum alloy.

In the present invention, it is preferable that the first metal base material and the second metal base material are cleaned and then stacked and welded; the cleaning is preferably to clean the surfaces of the first metal base metal and the second metal base metal by adopting alkali solution and then acid solution so as to remove grease and oxide films, improve the surface activity of aluminum alloy and ensure the quality of the welded joint; the alkali solution is preferably sodium hydroxide solution; the acid solution is preferably a dilute nitric acid solution.

In the invention, the zinc mass content in the zinc-containing metal is preferably more than or equal to 70%, more preferably more than or equal to 99.95%; the zinc-containing metal is preferably selected from pure zinc metal and/or zinc alloy.

In the present invention, the zinc-containing metal is preferably a sheet; the zinc-containing metal preferably has a thickness of 0.01 to 2mm, more preferably 0.05 to 1.5mm, still more preferably 0.1 to 1mm, still more preferably 0.2 to 0.8mm, still more preferably 0.3 to 0.6mm, and most preferably 0.4 to 0.5mm.

In the present invention, the welding is preferably performed in an inert atmosphere and/or a vacuum environment.

In the present invention, it is preferable to place a weight on the stacked structure during the welding, and the weight is preferably 0.1 to 10kg, more preferably 0.5 to 8kg, more preferably 1 to 6kg, more preferably 2 to 5kg, and most preferably 3 to 4kg.

In the present invention, the temperature of the welding is preferably 400 to 600 ℃, more preferably 450 to 550 ℃, and most preferably 500 ℃; the welding time is preferably 3 to 7 minutes, more preferably 5 minutes.

According to the invention, the first metal base metal and the second metal base metal are connected through welding, and the zinc sheet and the aluminum alloy base metal on two sides react and form a microstructure by controlling the heating temperature and the heating time, so that the performance of a welded joint can be ensured, and holes or cracks are not generated.

The welding temperature interval of the existing aluminum-silicon solder exceeds the recrystallization temperature or solidus temperature of most aluminum alloys, so that the aluminum alloy materials have the conditions of performance degradation and strength softening after welding. If the solidus temperature of the aluminum alloy 6061 is 582 ℃ (overburning temperature 580 ℃), the recrystallization temperature is between 350 and 500 ℃, and the melting point of the aluminum-silicon solder is 580 ℃; under the condition of ensuring that the solder is sufficiently melted, the welding temperature is required to be near 610 ℃, and in this way, the 6061 aluminum alloy base material is light and is over-burned in structure, and the 6061 aluminum alloy base material is softened and collapses.

The invention adopts the zinc sheet to replace aluminum-silicon solder for welding, and because the cost of the zinc sheet is lower, the processing and preparation process is simpler, the cost is lower, the external heating temperature required by welding is lower than that of the conventional aluminum-silicon solder, the aluminum-silicon solder can realize welding at the temperature of more than 600 ℃, and the pure zinc sheet can realize lower welding temperature. The invention can save energy, and can ensure that the performance of the welding base metal alloy is not lost, and the self characteristics of the aluminum alloy are not damaged.

Example 1

Providing a pure zinc sheet with the thickness of 0.05mm, placing the zinc sheet between two aluminum alloys, ensuring that the upper contact surface and the lower contact surface are covered completely, placing the zinc sheet in a stacking mode, pressing a weight of 1kg on the zinc sheet, continuously heating the zinc sheet for 5 minutes at the heating temperature of 500 ℃ under an inert atmosphere, and then placing the zinc sheet at room temperature for cooling to finish the welding connection of two aluminum alloy base materials; the two aluminum alloys are pure aluminum blocks with the brand of 1100, and the content of zinc in the pure zinc sheets is more than 99.95 percent.

The picture of the welded product in the embodiment 1 of the invention is shown in fig. 2, it can be seen that the pure zinc sheet is completely melted, and the joint interface is effectively fused with the aluminum alloy base materials on both sides, so that the weld joint area, the element diffusion area and the base materials can be clearly seen.

The hardness and conductivity of the aluminum alloy before and after welding in example 1 of the present invention were measured, and the hardness measurement method was GB/T4340.1-2009 "Vickers hardness test of Metal Material part 1: test method, conductivity detection method is GB/T12966-2022 aluminum and aluminum alloy conductivity vortex test method. The detection results are as follows:

example 2

Providing a pure zinc sheet with the thickness of 0.05mm, placing the zinc sheet between two aluminum alloys, ensuring that the upper contact surface and the lower contact surface are covered completely, placing the zinc sheet in a stacking mode, pressing a weight of 1kg on the zinc sheet, continuously heating the zinc sheet for 5 minutes at the heating temperature of 500 ℃ under an inert atmosphere, and then placing the zinc sheet at room temperature for cooling to finish the content connection of two aluminum alloy base materials; the two aluminum alloys are 3003 aluminum alloys, and the content of zinc in the pure zinc sheet is more than 99.95%.

A picture of the welded product of example 2 is shown in fig. 3.

The hardness and conductivity of the aluminum alloy before and after welding in example 2 were measured as in example 1, and the measurement results were as follows:

example 3

Providing a pure zinc sheet with the thickness of 0.05mm, placing the zinc sheet between two aluminum alloys, ensuring that the upper contact surface and the lower contact surface are covered completely, placing the zinc sheet in a stacking mode, pressing a weight of 1kg on the zinc sheet, continuously heating the zinc sheet for 5 minutes at the heating temperature of 500 ℃ under an inert atmosphere, and then placing the zinc sheet at room temperature for cooling to finish the welding connection of two aluminum alloy base materials; the two aluminum alloy brands are respectively 3003 aluminum alloy on the upper layer and 1100 pure aluminum blocks on the lower layer, and the content of zinc in the pure zinc sheet is more than 99.95 percent.

Example 3 a picture of the welded product is shown in figure 4.

The hardness and conductivity of the aluminum alloy before and after welding in example 3 were measured as in example 1, and the measurement results were as follows:

example 4

Providing a pure zinc sheet with the thickness of 0.05mm, placing the zinc sheet between two aluminum alloys, ensuring that the upper contact surface and the lower contact surface are covered completely, placing the zinc sheet in a stacking mode, pressing a weight of 1kg on the zinc sheet, continuously heating the zinc sheet for 5 minutes at the heating temperature of 500 ℃ under an inert atmosphere, and then placing the zinc sheet at room temperature for cooling to finish the welding connection of two aluminum alloy base materials; the two aluminum alloys are 6063 aluminum alloy, and the content of zinc in the pure zinc sheet is more than 99.95 percent.

Example 4 a picture of the welded product is shown in figure 5.

The hardness and conductivity of the aluminum alloy before and after welding in example 4 were measured as in example 1, and the measurement results were as follows:

While the invention has been described and illustrated with reference to specific embodiments thereof, the description and illustration is not intended to limit the invention. It will be apparent to those skilled in the art that various changes may be made in this particular situation, material, composition of matter, substance, method or process without departing from the true spirit and scope of the invention as defined by the following claims, so as to adapt the objective, spirit and scope of the present application. All such modifications are intended to be within the scope of this appended claims. Although the methods disclosed herein have been described with reference to particular operations being performed in a particular order, it should be understood that these operations may be combined, sub-divided, or reordered to form an equivalent method without departing from the teachings of the present disclosure. Thus, unless specifically indicated herein, the order and grouping of operations is not a limitation of the present application.

Claims

1. A method of joining aluminum alloys, comprising:

and welding the stacked structure.

2. The method for connecting aluminum alloy according to claim 1, wherein the zinc content of the zinc-containing metal is not less than 70% by mass.

3. The aluminum alloy joining method according to claim 1, wherein the zinc-containing metal is selected from pure zinc metal and/or zinc alloy.

4. The method of joining aluminum alloys according to claim 1, wherein said zinc-containing metal has a thickness of 0.01 to 2mm.

5. The method of joining aluminum alloys according to claim 1, wherein the temperature of said welding is 400-600 ℃.

6. The method of joining aluminum alloys according to claim 1, wherein said welding is for 3 to 7 minutes.

7. The method of joining aluminum alloys according to claim 1, wherein said welding is performed under inert atmosphere and/or vacuum conditions.

8. The method of joining aluminum alloys according to claim 1, wherein weights are placed on the stacked structure during said welding;

the weight of the weight is 0.1-10 kg.

9. The method of joining aluminum alloys according to claim 1, further comprising:

cleaning the first metal base material and the second metal base material;

10. The method for joining aluminum alloys according to claim 1, wherein said first metal base material is selected from one or more of a 1-series aluminum alloy, a 3-series aluminum alloy and a 6-series aluminum alloy;