KR102587294B1 - Brazing method of dissimilar metal panels and brazing clad metal panels by the method - Google Patents

Abstract

The present invention relates to a method for joining dissimilar metal panels using a high-temperature vacuum furnace, and a brazing clad metal using the same. More specifically, the method includes the following steps of: preparing a first metal base material and a second metal base material of a plate shape and ultrasonically cleaning the materials; deoxidizing the deoxidized first and second metal base materials; inserting a brazing filler metal sheet between the deoxidized first and second metal base materials, and then feeding the materials into a brazing furnace and forming a vacuum atmosphere; heating the first and second metal base materials, in which the filler metal sheet is inserted, to 950-1050℃ under a reduction atmosphere or a vacuum atmosphere and maintaining the materials for 1-2 hours, and then cooling the furnace to braze the materials; cooling the brazed brazing clad metal to a room temperature by feeding nitrogen; rolling the cooled brazing clad metal; and cutting and pressing the rolled clad metal, wherein the first and second metal base materials are dissimilar materials. In accordance with the present invention, the method can have an advantage of enabling brazing between large panels of dissimilar metal materials due to excellent bonding tightness, strength and processability between joined dissimilar metal materials. Moreover, the method can enable dissimilar metal brazing for not only existing small products but also large products, thereby having an advantage of applying brazing clad metal throughout the whole industry.

Description

Method for joining dissimilar metal plates using a high-temperature vacuum furnace and brazing clad metal using the same {BRAZING METHOD OF DISSIMILAR METAL PANELS AND BRAZING CLAD METAL PANELS BY THE METHOD}

The present invention relates to a method of joining dissimilar metal sheets and brazing clad metal using the same, and more specifically, to a technology for manufacturing metal sheets capable of secondary forming by joining dissimilar metal sheets using a high-temperature vacuum furnace. will be.

Dissimilar metal bonded plates are mainly used to form secondary processed products such as cookware, such as pots and frying pans, and thermal conductivity is very important. Therefore, very high confidentiality is required.

Previously, the most difficult material for high-end cookware was 2-ply dissimilar metals, and the only way to join them was 'rolled clad metal', which involves rolling dissimilar metals that passed through a heating furnace and joining them. However, this hot rolling method requires large facilities and has clear limitations in producing bonded materials of various thicknesses desired by the market. Additionally, the mass production method has disadvantages.

Among them, the two-ply bonding method of stainless steel (STS) and copper (COPPER) has the highest bonding difficulty. By combining STS, which is highly harmless to the human body, and COPPER, which is optimal for cookware due to its good thermal conductivity, the highest performance cookware can be developed. However, due to the shortcomings mentioned above, continuous production was not possible, so even though there was market demand, due to the narrowness of the high-end cookware market, STS+COPPER and 2-layer cladding of 2.5T or more were not produced and supplied, so it was discontinued.

On the other hand, brazing joining refers to a joining method of inserting a certain filler metal (filler metal) that melts at a temperature lower than the melting point of the part between the parts to be joined, and melting the filler metal to create a finished product. , Here, the term base material is not used and the term component is referred to because the brazing method mentioned above was mainly used for joining small parts less than 10 cm.

In other words, the conventional method of joining dissimilar metals using brazing is only used when joining small parts less than 10 cm, and when brazing large plates such as cookware, the joint airtightness is not good and the metal properties become soft after brazing. It could not be used for development purposes.

KR 10-1288854 B1 KR 10-2317581 B1

Therefore, the purpose of the present invention is the process of deoxidation to remove the oxygen content in the metal, which causes bubbles to decrease the airtightness of the joint, the development of filler metal sheets that are essential for uniform jointing in addition to airtightness, and the process of sheet alloy ratio. , a process of controlling the heating temperature and cooling time, and a re-rolling process that turns the soft metal after brazing into a hard one. A brazing clad metal manufacturing method that manufactures high-quality brazing clad metal, and the brazing clad metal produced by the method. It is to provide.

The method of joining dissimilar metal plates using a high-temperature vacuum furnace of the present invention to solve the above object includes preparing a plate-shaped first metal base material and a second metal base material, and combining the prepared first metal base material and the second metal base material. A step of ultrasonically cleaning the base material, deoxidizing the cleaned first metal base material and the second metal base material by heating them to 900 to 1000° C. under a vacuum atmosphere, and between the deoxidized first metal base material and the second metal base material. After inserting the brazing filler metal sheet into the brazing furnace, creating a vacuum atmosphere, the first metal base material and the second metal base material into which the filler metal sheet is inserted are heated at 950 to 1050° C. under a reducing atmosphere or a vacuum atmosphere. Raising the temperature to and maintaining it for 1 to 2 hours, brazing by furnace cooling to 300 to 500°C, cooling the brazed brazing clad metal to room temperature by adding nitrogen, and rolling the cooled brazing clad metal. and cutting and press processing the rolled clad metal, wherein the first metal base material and the second metal base material are different materials.

The first metal base material is copper, and the second metal base material is stainless steel.

The brazing filler metal sheet is characterized in that it is composed of 0.01-0.05% by weight of Pb, 0.05-0.15% by weight of Fe, 5.0-9.0% by weight of Sn, 0.1-0.3% by weight of Zn, 0.01-0.05% by weight of P, and the balance of Cu. .

The plate-shaped first metal base material and the second metal base material are characterized in that the width, length, or diameter is 30 cm or more.

The step of rolling the cooled brazing clad metal is characterized in that rolling is performed twice.

And the brazing clad metal according to the present invention is characterized in that it is manufactured by the above-described method.

The method of joining dissimilar metal plates using a high-temperature vacuum furnace according to the present invention and the brazing clad metal using the same are the world's only material development technology that allows secondary processing of large plates into cookware by brazing large plates without air pockets. Brazing between large plates of different metals is possible due to excellent joint tightness, strength, and processability. Brazing of different metals is possible not only for conventional small products but also for large products, so brazing clad metal can be applied throughout the industry. There is.

1 is a flowchart showing a method of joining dissimilar metal plates according to the present invention.

Hereinafter, the present invention will be described in detail.

The present invention relates to a technology for producing a metal sheet capable of secondary forming processing by joining dissimilar metals using a vacuum furnace. It should be noted that the metal sheet manufactured in the present invention is called 'brazing clad metal'.

This brazing clad metal is mainly used as a material for processing cookware, and thermal conductivity is important, so it requires very high airtightness. Therefore, not generating air pockets that reduce thermal conductivity is the key to manufacturing brazing clad metal according to the present invention. In addition, conventional rolled clad metal could only be produced in large quantities, but the brazing clad metal of the present invention has the feature of being able to be produced in small quantities.

More specifically, the method of joining dissimilar metal sheets according to the present invention, that is, the method of manufacturing brazing clad metal, has auxiliary processes, uses, and production processes compared to the method of joining small-sized parts and parts, which is the brazing joining method so far. It is different, and the core technology is to join large metal plates side to side to increase airtightness without leaving any air gaps. It is impossible to manufacture such large dissimilar metal sheets using conventional brazing methods, and brazing clad metal is a metal material technology that can be used widely in production and industrial sites as a sheet shape that can be subjected to secondary forming processing. Other than the commonality of using a vacuum furnace to join small parts to other brazing methods, there are differences in the alloy ratio for turning filler metal into a thin sheet, deoxidation, rolling, and temperature control, and other techniques and processes that are not found in conventional brazing. It is a completely different metal material root technology with added elements.

The method of joining dissimilar metal sheets using a high-temperature vacuum furnace according to the present invention includes preparing a plate-shaped first metal base material and a second metal base material, and ultrasonically cleaning the prepared first metal base material and the second metal base material. and deoxidizing the washed first metal base material and the second metal base material by heating them to 900-1000° C. under a vacuum atmosphere, and placing a brazing filler metal sheet between the deoxidized first metal base material and the second metal base material. After insertion, it is placed in a brazing furnace and a vacuum atmosphere is created, and the first metal base material and the second metal base material into which the filler metal sheet is inserted are heated to 950-1050°C under a reducing atmosphere or vacuum atmosphere to process 1-2. After maintaining the time, brazing by furnace cooling to 300 to 500°C, cooling the brazed brazing clad metal to room temperature by adding nitrogen, rolling the cooled brazing clad metal, and rolling the cooled brazing clad metal. It is characterized in that it includes the step of cutting and press processing the clad metal.

Hereinafter, this will be described in detail step by step with reference to FIG. 1.

Step of preparing a plate-shaped first metal base material and a second metal base material

First, prepare a plate-shaped first metal base material and a second metal base material. Since the first and second metal base materials are materials that are joined together, it is natural that their sizes and shapes correspond to each other.

In addition, the first and second metal base materials are different types of metals, and the materials are not limited, but for example, the first metal base material may be copper, and the second metal base material may be stainless steel, more specifically, 300 series stainless steel. there is. This is because copper and stainless steel are materials that can be widely used industrially, for example, as high-end cookware, but their use is limited because it is difficult to braze them in the case of large plates.

In addition, the plate-shaped first metal base material and the second metal base material may have a width, length, or diameter of 30 cm or more, and the present invention has the advantage of being able to apply brazing to large plate-shaped products that were conventionally difficult to braze. However, it is natural that the present invention can be applied not only to large products but also to small products.

Ultrasonic cleaning the prepared first metal base material and the second metal base material

Next, the prepared first metal base material and the second metal base material are ultrasonically cleaned.

The ultrasonic cleaning involves precipitating the first metal base material and the second metal base material in a water-soluble ultrasonic cleaner for 15 to 25 minutes while cleaning them using an ultrasonic cleaning device that emits ultrasonic energy at a frequency of 10 KHz to 200 KHz. At this time, the ultrasonic cleaner such as KCU-G510C, which is commercially available, can be used, and the type is not limited. In addition, the ultrasonic cleaning device can also use a variety of previously published products, so the types are not limited.

Deoxidizing the washed first metal base material and second metal base material by heating them to 900-1000°C under a vacuum atmosphere.

Next, oxygen in the first metal base material or the second metal base material is precipitated and removed by heating the washed first metal base material and the second metal base material under a vacuum atmosphere to 900-1000°C, most preferably to 1000°C. . And it is natural to cool it to room temperature.

In the present invention, the joint airtightness between the first metal base material and the second metal base material is increased through this deoxidation process, and brazing of large products becomes possible due to the increase in the joint airtightness.

Inserting a brazing filler metal sheet between the deoxidized first metal base material and the second metal base material, then putting it into a brazing furnace and creating a vacuum atmosphere.

Then, a brazing filler metal sheet is inserted between the deoxidized first metal base material and the second metal base material. The brazing filler metal sheet may be inserted in the form of a thin film with a thickness of 1.0 to 10㎛, but is not limited to this, and is laminated on the joint surface of the first metal base material or the second metal base material by a method such as sputtering to form a brazing filler metal sheet. You can also allow sheets to be inserted.

The brazing filler metal sheet is used as a filler material for the first metal base material and the second metal base material, and contains Pb 0.01-0.05% by weight, Fe 0.05-0.15% by weight, Sn 5.0-9.0% by weight, Zn 0.1-0.3% by weight, It is preferably composed of 0.01 to 0.05% by weight of P and the balance of Cu. This is because the brazing filler metal sheet having the above composition increases the joint strength and joint airtightness between the first metal base material and the second metal base material.

After inserting the filler metal sheet, brazing preparation is completed by inserting it into the brazing furnace, placing it between the upper pressurizing jig and the lower pressurizing jig, and creating a vacuum atmosphere.

Brazing the first metal base material and the second metal base material into which the filler metal sheet is inserted by raising the temperature to 950-1050°C under a reducing atmosphere or a vacuum atmosphere, maintaining it for 1-2 hours, and then cooling to 300-500°C.

Next, while maintaining the atmosphere in the brazing furnace in which the first metal base material and the second metal base material into which the filler metal sheet is inserted is placed as a reducing atmosphere or a vacuum atmosphere, the temperature is 950 to 1050° C. Most preferably, the temperature is raised to 1000°C and maintained for 1 to 2 hours so that the brazing filler metal sheet is dissolved and the first metal base material and the second metal base material are brazed. At this time, the reducing atmosphere can be created by injecting argon gas, an inert gas, etc., using a known method.

Then, it is heated to 300~500℃ to produce brazing clad metal.

Cooling the brazed brazing clad metal to room temperature by adding nitrogen to it.

Then, nitrogen gas is introduced into the brazed brazing clad metal to cool it to room temperature. This is to stably enhance the properties of the base material as well as manufacturing efficiency.

Rolling the cooled brazing clad metal

Next, by rolling the cooled brazing clad metal, it is not only flattened but also its thickness is adjusted. In addition, the generation of stress changes the properties of the first metal base material and the second metal base material to enhance strength. This is because the base material that has been too softened by high heat has poor workability, and the strength of the base material made of copper and stainless steel is difficult to increase through heat treatment, so the strength is increased through the rolling process.

At this time, the rolling can be performed by either cold rolling or hot rolling, and hot rolling is preferably performed at 400 to 500°C.

In addition, the rolling may be performed once, but it is natural that the rolling process may be performed twice depending on the required thickness and strength.

Cutting and press processing the rolled clad metal

Then, the rolled brazing clad metal is press cut to the desired size and shape, inserted into a mold tool, and then pressed into shape by applying a certain amount of pressure.

The cutting and press processing are performed according to the prior art, and further description thereof will be omitted.

As described above, the brazing clad metal of the present invention joined as described above has the advantage of high gas tightness between dissimilar metals, excellent strength, and excellent workability. In addition, it has the advantage of being able to be used across industries as brazing between large plates of different types is possible.

Hereinafter, the present invention will be described in detail through examples.

(Example 1)

A copper base material, a circular plate with a diameter of 30 cm, and a 304 stainless steel base material, a circular plate with a diameter of 30 cm, were prepared. After ultrasonic cleaning by settling in KCU-G510C, an ultrasonic cleaner, for 20 minutes, it was deoxidized by heating to 1000°C in a vacuum atmosphere at a rate of 100°C/min and maintaining it for 3 minutes.

Then, prepare a thin film with a thickness of 5㎛ consisting of 0.02wt% of Pb, 10wt% of Fe0, 7.0wt% of Sn, 0.20wt% of Zn, 0.03wt% of P, and the balance of Cu, and place the thin film between the copper base material and the stainless steel base material. After that, it was put into a brazing furnace and a vacuum atmosphere was created. Then, the temperature was raised to 1010°C at a rate of 100°C/min and maintained for 1.5 hours, then furnace cooled to 400°C and cooled to room temperature at a cooling rate of 50°C/min while nitrogen was added again.

Next, the cooled specimen was flattened by cold rolling at a thickness reduction rate of 30%.

(Comparative Example 1)

The same procedure as Example 1 was performed, but the deoxidation process was omitted, and a 5㎛ thick thin film composed of 65% by weight Ag and 35% Cu was used.

(Test Example 1)

A tensile test (ASTM E 8/E8M-08) was performed to measure the joint strength of the dissimilar metal joining alloy specimens prepared in Example 1 and Comparative Example 1, and the results are shown in Table 1 below.

Test Example 1 Results division Yield strength (Mpa) Tensile strength (Mpa) Example 1 321 451 Comparative Example 1 241 321

As can be seen in Table 1, it was confirmed that Example 1 of the present invention had superior strength compared to Comparative Example 1.

The best embodiments of the present invention are disclosed in the drawings and specification. Here, specific terms are used, but they are used only for the purpose of explaining the present invention and are not used to limit the meaning or scope of the present invention described in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent embodiments of the present invention are possible therefrom. Therefore, the true technical scope of the present invention should be determined by the technical spirit of the attached claims.

Claims (6)

Preparing a plate-shaped first metal base material and a second metal base material;
Ultrasonic cleaning the prepared first metal base material and the second metal base material;
Deoxidizing the washed first metal base material and the second metal base material by heating them to 900-1000° C. under a vacuum atmosphere;
Inserting a brazing filler metal sheet between the deoxidized first metal base material and the second metal base material and then putting it into a brazing furnace to create a vacuum atmosphere;
A step of brazing the first metal base material and the second metal base material into which the filler metal sheet is inserted by raising the temperature to 950 to 1050 ° C. under a reducing atmosphere or a vacuum atmosphere and maintaining it for 1 to 2 hours, then cooling to 300 to 500 ° C. ,
Cooling the brazed brazing clad metal to room temperature by adding nitrogen;
rolling the cooled brazing clad metal;
It includes cutting and press processing the rolled clad metal,
The first metal base material and the second metal base material are different materials,
The brazing filler metal sheet is characterized in that it consists of 0.01 to 0.05% by weight of Pb, 0.05 to 0.15% by weight of Fe, 5.0 to 9.0% by weight of Sn, 0.1 to 0.3% by weight of Zn, 0.01 to 0.05% by weight of P, and the balance of Cu. A method of joining dissimilar metal plates using a high-temperature vacuum furnace.
According to paragraph 1,
A method of joining dissimilar metal sheets using a high-temperature vacuum furnace, wherein the first metal base material is copper and the second metal base material is stainless steel.
delete According to paragraph 1,
The plate-shaped first metal base material and the second metal base material are,
A method of joining dissimilar metal plates using a high-temperature vacuum furnace, characterized in that the width, length, or diameter is 30 cm or more.
According to paragraph 1,
A method of joining dissimilar metal sheets using a high-temperature vacuum furnace, characterized in that the step of rolling the cooled brazing clad metal is rolling twice.
Brazing clad metal, characterized in that it is joined by the joining method according to any one of claims 1, 2, 4, and 5.