KR102310325B1 - Brazing method and apparatus for preventing surface oxidation - Google Patents

Abstract

A brazing method according to an embodiment of the present disclosure is a brazing method of a brazing object including a first object and a second object, the step of supplying a filler metal and a flux to the gap between the first object and the second object, by a heating unit and heating the first object, melting the filler metal and the flux, and the filler metal and the flux are solidified to bond the first object and the second object to each other.

Description

Brazing method and apparatus for surface oxidation prevention

The present disclosure relates to a brazing method and apparatus, and more particularly, to a brazing method and apparatus for preventing surface oxidation.

In general, metal or non-metal bonding techniques are classified into welding, brazing, soldering, and the like.

Welding is a technique for joining metals or non-metals of the same or different materials to each other by melting them with heat or pressure. Welding is fusion welding after raising the temperature of the object to be welded to the melting point, but thermal deformation such as distortion or bulging due to residual stress may be caused. In particular, in the case of precision parts where product dimensions or surface quality are important, thermal deformation can deteriorate the quality of parts.

In welding, it is difficult to melt the object to be welded, and quality control is difficult. When exposed to the sensitization temperature range for more than a certain period of time during material welding and heat treatment, chromium (Cr) around the grain boundary combines with carbon (C _{) to precipitate chromium carbide (Cr 23} C ₆ ), causing intergranular corrosion, After bonding is completed, residual stress remains inside the material, which may cause material destruction. To reduce residual stress, additional components must be added, heat treated, or surface oxidized parts must be removed through post-treatment. In addition, welding equipment is difficult to move and install, so there are many restrictions on use.

On the other hand, brazing uses a filler metal having a lower melting point than that of the brazing object, and only the filler metal is melted without the brazing object being melted. The molten filler metal fills the gap between the objects to be brazed, and at this time, the spreadability, wettability or capillary phenomenon of the filler metal is used. If brazing is used, deformation and damage to the product can be prevented while maintaining adequate strength. Brazing includes furnace brazing, vacuum brazing, torch brazing, DIP brazing, high frequency brazing, and resistance brazing.

Among them, torch brazing is a method of applying heat with a brazing torch using filler metal locally only on the part to be brazed when local partial brazing is required. Various gases are used as heat sources, and mainly manual torch brazing and automatic torch divided by brazing.

However, during the heating process for brazing, surface oxidation may occur in the object to be brazed, and a problem of low bonding strength between the objects to be brazed may occur.

An object of the present disclosure is to provide a brazing method that prevents surface oxidation of a brazing object or reduces an oxidation rate and has a high bonding strength at a low cost.

A brazing method according to an embodiment of the present disclosure includes the steps of supplying a filler metal and a flux to a gap between a first object and a second object, heating the first object by a heating unit, melting the filler metal and the flux; and a step in which the filler metal and the flux become solid and the first object and the second object are combined with each other.

In a brazing method according to an embodiment of the present disclosure, the first object includes a Cu component.

A brazing method according to an embodiment of the present disclosure includes a heating unit heating the surface of the first object spaced apart from the boundary between the first object and the second object by about 5 to 10 mm.

The brazing method according to an embodiment of the present disclosure further includes supplying at least one of acetylene, ethylene, LPG, LNG, and hydrogen to the heating unit.

In the brazing method according to an embodiment of the present disclosure, the second object corresponds to the STS pipe.

According to an embodiment of the present disclosure, the melting point of the flux is lower than that of the filler metal.

According to an embodiment of the present disclosure, the melting temperature difference (ΔT) between the filler metal and the flux is 200° C. or more.

A brazing method according to an embodiment of the present disclosure includes heating the surface of the first object except for the overlapping portion formed by the first object and the second object among the surfaces of the first object.

A brazing method according to an embodiment of the present disclosure includes melting a filler metal and a flux using heat conduction of a first object.

In the brazing method according to an embodiment of the present disclosure, any one of the first object and the second object corresponds to an expanded tube having a relatively large diameter, and the other one corresponds to a narrow tube having a relatively small diameter, and the narrow tube corresponds to an enlarged tube. Some are inserted to form an overlap.

A brazing apparatus according to an embodiment of the present disclosure is a brazing apparatus for heating a first object, and includes a heating unit configured to heat a first object containing a Cu component and a gas unit for supplying a combustible gas to the heating unit do.

A brazing apparatus according to an embodiment of the present disclosure includes a heating unit configured to heat the surface of the first object spaced apart from the boundary between the first object and the second object by about 5 to 10 mm.

The brazing apparatus according to an embodiment of the present disclosure is configured to heat the surface of the first object except for the overlap formed by the first object and the second object among the surfaces of the first object, using heat conduction of the first object and a heating unit for melting the filler metal and the flux.

Brazing device according to an embodiment of the present disclosure includes a heating unit corresponding to a single tip (Single Tip) or a double tip (Double Tip).

By using various embodiments of the present disclosure, it is possible to provide brazing that melts the filler metal and the flux by using the heat conduction of the pipe including the Cu component.

By using various embodiments of the present disclosure, it is possible to provide brazing that has high brazing joint strength and prevents surface oxidation of the brazing object.

By using various embodiments of the present disclosure, it is possible to provide brazing to prevent oxidation of the surface of the brazing object or reduce the oxidation rate even using a brass filler metal.

By using various embodiments of the present disclosure, it is possible to provide brazing that prevents surface oxidation of the brazing object or reduces the oxidation rate even if a filler metal containing no or less silver (Ag) is used.

The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present disclosure will be described with reference to the accompanying drawings described below, wherein like reference numerals denote like elements, but are not limited thereto.
1 is a view showing a brazing apparatus 100 and a brazing object 200 according to an embodiment of the present disclosure.
Figure 2 is a view showing the first object 210 and the second object 220 of the brazing object 200 according to an embodiment of the present disclosure.
3 is an enlarged view along the dotted line X of the brazing object 200 shown in FIG. 1 , and is a photograph showing a heating position by the heating unit 110 according to an embodiment of the present disclosure.
4 is an enlarged view along the dotted line X of the brazing object 200 shown in FIG. 1 , and is a photograph showing a heating position by the heating unit 110 according to another embodiment of the present disclosure.
5 is a flowchart illustrating a brazing method according to an embodiment of the present disclosure.
6 is a perspective view showing a brazing apparatus 100 and a brazing object 200 according to another embodiment of the present disclosure.

Hereinafter, specific contents for carrying out the present disclosure will be described in detail with reference to the accompanying drawings. However, in the following description, if there is a risk of unnecessarily obscuring the subject matter of the present disclosure, detailed descriptions of well-known functions or configurations will be omitted.

Throughout this specification, when a member is said to be located "on" another member, this means not only when a member is in contact with another member but also when another member exists between the two members unless otherwise stated. include

Before describing the embodiments of the present disclosure in detail, the upper side of the drawing may be referred to as “upper” or “upper side” and the lower side as “lower” or “lower side” of the configuration shown in the drawing. In addition, in the drawings, the remaining portions between the upper and lower portions of the illustrated configuration or except for the upper and lower portions may be referred to as “side” or “side”.

Throughout this specification, when a part "includes" a component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used throughout this specification, the terms "about", "substantially" and the like are used to encompass the tolerance when there is a tolerance.

Throughout this specification, the term "combination(s) of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, It means to include one or more selected from the group consisting of the above components.

Throughout this specification, reference to "A and/or B" means "A, or B, or A and B."

Throughout this specification, when a part is said to be "connected" with another part, it includes not only a case in which it is directly connected, but also a case in which it is connected through another configuration in the middle.

Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art to which the present application pertains can easily implement them. The present application may be embodied in several different forms and is not limited to the embodiments described herein.

In the accompanying drawings, identical or corresponding components are assigned the same reference numerals. In addition, in the description of the embodiments below, overlapping description of the same or corresponding components may be omitted. However, even if descriptions regarding components are omitted, it is not intended that such components are not included in any embodiment. Relative terms such as "upper", "upper", etc. may be used to describe the relationship between the components shown in the drawings, and the present disclosure is not limited by such terms.

1 is a view showing a brazing apparatus 100 and a brazing object 200 according to an embodiment of the present disclosure.

The brazing apparatus 100 corresponds to an apparatus for melting filler metal used to bond the brazing objects 200 to each other. As an embodiment, the brazing device 100 may correspond to a torch device using a combustible gas. However, the present disclosure is not limited thereto, and the brazing apparatus 100 may correspond to an induction heating apparatus.

The brazing apparatus 100 may include a heating unit 110 and a gas unit 120 . The heating unit 110 may use the combustible gas supplied from the gas unit 120 as a heat source. For example, the heating unit 110 may correspond to a torch capable of melting the filler metal using heat generated by burning the combustible gas.

The heating unit 110 is configured to heat a portion containing the Cu component of the brazing object 200 . In one embodiment, the brazing object 200 includes a first object 210 and a second object 220, of which the first object 210 may include a Cu component. The heating unit 110 is configured to heat the surface of the first object 210 spaced apart from the boundary portion 231 between the first object 210 and the second object 220 by about 5 to 10 mm.

A difference may occur in the oxidation rate of the surface of the brazing object 200 according to the heating position of the heating unit 110 . By melting the filler metal using heat conduction by the Cu component of the brazing object 200 (eg, heat conduction by the Cu component included in the first object) by applying heat at a location where the heating unit 110 is spaced apart from the filler metal, brazing It is possible to significantly reduce the surface oxidation rate of the object. On the other hand, when the heating unit 110 directly applies heat (eg, flame) to the filler metal to melt the filler metal, the surface oxidation rate of the brazing object may rapidly increase due to the combustion action due to the high flame temperature. A specific heating position of the heating unit 110 will be described in more detail with reference to FIGS. 3 and 4 .

Meanwhile, the heating unit shown in FIG. 1 is illustrated as having a single tip shape, but is not limited thereto, and may have, for example, another shape (eg, a double tip shape). This will be described with reference to FIG. 6 .

The gas unit 120 may supply a combustible gas suitable for combustion to the heating unit 110 . The combustible gas may correspond to any one or a combination of acetylene, ethylene, LPG, LNG, and hydrogen, and oxygen and/or air may be additionally mixed.

Acetylene (C ₂ H ₂ ) gas may correspond to a compound of carbon and hydrogen. Acetylene gas can be used to braze iron products such as automobile parts and metal furniture. When using acetylene gas, a flashback preventer may be additionally attached to the brazing apparatus 100 and used. The maximum temperature of the flame is about 3,127℃.

Ethylene (C ₂ H ₄ ) gas can be used as a substitute for acetylene gas, and although the manufacturing cost is lower than that of acetylene, an effect similar to acetylene can be obtained.

LPG (Liquified Petroleum Gas) is called LP gas or liquefied petroleum gas. LPG is a petroleum hydrocarbon that turns into a liquid when pressurized at room temperature. LPG components are C ₃ H ₈ , C ₃ H ₆ , C ₄ H ₁₀ , C ₄ H ₈ and the like. The maximum flame temperature is about 2,526°C.

LNG (Liquified Natural Gas) is _{a gas in a liquefied state by cooling natural gas containing methane (CH 4} ) as a main component, and is a combustible gas containing hydrocarbons as a main component. The maximum flame temperature is about 2,538℃.

Hydrogen (H ₂ ) has almost no flame during combustion, and the maximum flame temperature is about 4,820°C.

The gas unit 120 may supply combustible gas to the heating unit 110 . The heating unit 110 generates a flame by burning the supplied combustible gas. The flame of the heating unit 110 heats a portion of the surface of the brazing object 200 containing the Cu component. The heat transferred by the high thermal conductivity of the Cu component melts the filler metal, thereby remarkably reducing the surface oxidation rate of the brazing object 200 as compared to the case where the filler metal is directly heated using a flame. In the case of torch brazing, if the thermal conduction method using the Cu component is used, it is possible to prevent surface oxidation of the brazing object while using a filler metal that does not contain silver (Ag) or contains a small amount, and it is possible to provide a high-strength brazing joint. have.

The brazing object 200 includes a first object 210 and a second object 220 . One of the brazing objects 200 may correspond to an STS pipe, and the other may correspond to a copper (Cu) pipe. The first object 210 and the second object 220 have a pipe shape, and one of the objects may have a larger diameter than the other. A small-diameter pipe (narrow pipe) is inserted into a large-diameter pipe (expanded pipe), and the overlapping portion 230 may be formed. A gap between objects may be formed in the overlapping portion 230 . The filler metal permeates into the gap between the objects to be brazed and hardens or solidifies to form a joint. Furthermore, a boundary portion 231 between the objects is formed at the end of the overlapping portion 230 formed by the first object and the second object. The boundary portion 231 may include a portion of a joint portion formed in a gap between the first object and the second object.

The joint portion includes a joint portion between the objects to be brazed and a portion adjacent thereto. The joint includes filler metal and/or flux. The junction may correspond to a layer that is stuck to the oxide as the flux melts. The first object 210 and the second object 220 may be joined using a butt joint, a lap joint, a mixed type joint, or the like. The form of the joint may have a butt and an overlap form, and both forms may be mixed and used. The shape of the joint can be changed according to various conditions such as the characteristics of the brazing object and the desired joint strength.

Filler metal is a material included in the joint, and is lower than the melting point of the brazing object 200 . Through the heating process, the filler metal is melted before the brazing object 200, fills the gap between the first object 210 and the second object 220, and then solidifies to form a joint. The filler metal may correspond to one or a combination of silver alloy filler metal, brass filler metal, phosphor copper filler metal, silver filler metal, aluminum filler metal, heat-resistant alloy filler metal, or a combination thereof.

The main components of the silver alloy filler metal are Ag, Cu, Zn, and Cd, Ni, Sn, Mn, In, etc. may be added depending on the use. Silver alloy filler metal has a relatively low melting point (about 700°C), so it is easy to work with, and has excellent strength and elongation due to good fluidity. It is used for brazing of non-ferrous alloys except aluminum and magnesium, steel, copper, and copper alloys.

Brass filler metal is a copper alloy containing 60% or less of copper (Cu) and zinc (Zn), and is used for brazing copper, copper alloy, and some steels. The melting point is about 850 ~ 1050 ℃. Brass filler metal has low electrical conductivity and low resistance to vibration.

Phosphorus copper filler metal is a copper alloy obtained by alloying copper (Cu) with phosphorus (P) or copper (Cu) with phosphorus (P) and silver (Ag), and is used for brazing copper or copper alloys.

The silver filler metal is a copper-zinc-nickel (Cu-Zn-Ni) alloy, the higher the nickel (Ni) content, the higher the melting point. Common components are copper 47%, zinc 11%, nickel 42%, copper, brass, nickel Used for brazing of alloys and steels.

Aluminum filler metal is an aluminum alloy containing aluminum (Al) as a main component and alloying silicon (Si), copper (Cu), etc., and has a melting point of about 600°C. Aluminum filler metal is usually used for zinc-based alloys.

The heat-resistant alloy filler metal includes nickel-chromium (Ni-Cr)-based, silver-manganese (Ag-Mn)-based, copper-gold (Cu-Au)-based, and the like. Heat-resistant alloy filler metal is used for brazing of jet engines, gas turbines, STSs, etc., which are heat-resistant and corrosion-resistant materials.

Flux is a material included in the joint, which melts and liquefies the metal oxide generated during the heating process of brazing to prevent oxidation of the surface of the object to be brazed and to penetrate the filler metal into the joint.

The flux is to prevent oxidation on the surface of the brazing object to obtain a uniform brazing joint surface. In general, a chemical reaction proceeds when a metal is exposed to air, and the degree is more severe as the temperature increases. Therefore, if a metal and a metal must be joined, the temperature must be raised and the oxidation reaction takes place on the surface of the metal because it comes into contact with air. Flux is needed to cope with this phenomenon. The flux may directly decompose or remove oxides or other unnecessary substances, or may prevent the formation of unnecessary substances. The flux can be applied to the joint, or the flux can be added to the filler metal.

The flux may have a lower melting point than the filler metal. Furthermore, the flux may vaporize when the filler metal is in a molten state (or liquid state). Accordingly, the flux can more effectively prevent surface oxidation of the brazing object, which is generated during the heat conduction process of the heated first object.

For example, the silver alloy filler metal has a brazing operation temperature of about 700°C. Although it contains silver (Ag) and has a relatively low melting point, the cost is high due to the Ag content, and oxides are generated on the surface of the object to be brazed after brazing. For brass filler metal, the brazing operation temperature is around 900℃. Since the melting point is about 820 ~ 930 ℃, when overheated, zinc evaporates and porosity increases during the bonding process, and oxides are also generated on the surface of the brazing object. Oxidation of the surface of the brazing object may be more severe if no flux is added to the filler metal, or if the flux is melted later than the filler metal even if the flux is added.

To solve this, when using a flux having a lower melting point than the filler metal according to an embodiment of the present disclosure, the flux is first melted before the filler metal is melted due to heat conduction by the Cu component of the brazing object to enter a liquid state. It can prevent oxidation of the surface. Such a phenomenon of preventing oxidation of the surface of the brazing object may be more pronounced when the flux is vaporized when the filler metal is in a molten state (or a liquid state). To take advantage of this phenomenon, by using a flux having a melting point lower than the melting point of the filler metal, or by using a flux that may be in a vaporized state when the filler metal is in a molten state, oxidation of the surface of the brazing object can be prevented.

The flux, which becomes liquid (or melted) at about 500 ° C. to 850 ° C., is 10 to 30 wt % of Potassium Fluoride (KF), 10 to 30 wt % of Potassium Bifluoride (HF ₂ K), and Boric acid (Boric Acid, H ₃ BO ₃ ) 40 to 60% by weight may be included.

Flux that becomes liquid (or melted) at about 600 ℃ ~ 950 ℃, potassium fluoride (KBF ₄ ) 25 ~ 55% by weight, potassium bifluoride (Potassium Bifluoride, HF ₂ K) 5 ~ 40 weight %, potassium pentaborate (Potassium Pentaborate, KB ₅ O ₈ ) 1 to 10% by weight, and boron (Boron, B) 10 to 40% by weight.

According to an embodiment of the present disclosure, a combination of the high-temperature filler metal-low-temperature flux may be used. High or low is the melting point as a reference, and in the case of a combination of high-temperature filler metal and low-temperature flux, the melting point of the filler metal is higher than that of the flux. Therefore, if the melting point of the filler metal is higher than the flux, the principle according to the present disclosure can be used, and there is no limitation on the components contained in the high temperature filler metal. For example, even if the filler metal contains silver (Ag) or a silver alloy, if the melting point of the filler metal is higher than the flux, it may correspond to an embodiment of the present disclosure. Start of brazing by heat conduction of the heated first object by reducing costs by using a filler material that does not contain or contains less silver (Ag), and using a flux that has a lower melting point than the filler material and becomes liquid in a low temperature range It prevents surface oxidation by removing surface oxides.

The melting point of the filler metal can be more than 200°C higher than the flux. In this case, since the flux is melted before the filler metal, the process time of the brazing operation is reduced, and the oxidation time of the surface of the brazing object is reduced, thereby preventing oxidation. During the time the object to be brazed is heated, the flux is first melted to remove oxides on the surface of the object to be brazed.

2 is a view showing the first object 210 and the second object 220 of the brazing object 200 according to an embodiment of the present disclosure.

The brazing object 200 includes a first object 210 and a second object 220 . One of the first object 210 and the second object 220 may correspond to an expanded tube having a relatively large diameter, and the other may correspond to a narrow tube having a relatively small diameter. The narrow tube may be partially inserted into the expanded tube to form the overlapping portion 230 . As shown in FIG. 2 , in the expansion of the tube, only the portion corresponding to the overlapping portion 230 has a relatively large diameter, and the diameter of the portion excluding the overlapping portion may be smaller than that. The shape of the expanded tube is not limited by FIG. 2 , and for example, the diameter of the expanded tube may be uniform as a whole.

The expanded tube may include a Cu component, and the narrow tube may include a component different from Cu (eg, a component corresponding to STS). Alternatively, the narrow tube may include a Cu component, and the expanded tube may include a component different from Cu (eg, a component corresponding to STS).

The copper pipe including the Cu component may correspond to a pipe made of copper or a copper alloy. The copper pipe may include K, L, and M-type pipes classified according to thickness, and the shape of the pipe may be variously modified according to the purpose of use.

A pipe including a component different from Cu may correspond to a steel pipe or a STS (Stainless Steel) pipe. The STS pipe may mean a pipe manufactured by using chromium (Cr) or alloy steel containing chromium and nickel (Ni) for the purpose of improving corrosion resistance, and the chromium content may correspond to 12% or more. _{Chromium carbide (Cr 23} C ₆ ) is formed in the brazing process of the STS pipe, and therefore, after brazing is completed, residual stress remains inside the material, which may cause material destruction. Therefore, in order to reduce the residual stress, additional components must be added, heat treated, or surface oxidized parts must be removed. The present disclosure can solve the above-mentioned problem by preventing oxidation of the surface of the steel or STS pipe during brazing.

As shown in FIG. 2 , when the second object 220 corresponds to the narrow tube and the first object 210 corresponds to the enlarged tube, the second object 220 is inserted into the first object 210, the overlapping portion 230 may be formed. The overlapping portion 230 means a portion where one of the first object 210 and the second object 220 is inserted into the other and can be combined with each other, and the diameter of the first object 210 as shown in FIG. 2 . It can correspond to this relatively large area. When the first object 210 and the second object 220 are coupled to each other to form the overlapping portion 230 , the boundary portion 231 is formed by the first object 210 and the second object 220 . The boundary portion 231 may correspond to the end of the expanded tube or the first object 210 as shown in FIG. 2 .

3 is an enlarged view along the X dotted line of the brazing object 200 shown in FIG. 1 , and is a photograph showing a heating position by the heating unit 110 according to an embodiment of the present disclosure.

According to an embodiment of the present disclosure, the first object 210 includes a Cu component and corresponds to an expanded tube having a relatively large diameter. The second object 220 corresponds to an STS pipe and a narrow pipe having a relatively small diameter. Further, a boundary portion 231 is formed at the end of the overlapping portion 230 formed by combining the first object and the second object. The boundary portion 231 may include a junction formed in a gap between the first object and the second object. The joint portion includes a portion where the filler metal and the flux are melted and joined to the gap between the first object 210 and the second object 220 . A portion 232 of the bonding portion may be formed to extend from the boundary portion 231 .

The heating position of the heating unit 110 needs to be spaced apart from the boundary portion 231 formed by the first object 210 and the second object 220 to an appropriate position. According to an embodiment of the present disclosure, the heating unit 110 is spaced apart from the boundary portion 231 formed by the first object 210 and the second object 220 by about 5 to 10 mm of the first object 210 . configured to heat the surface. That is, a distance between the position D of the first object 210 heated by the heating unit 110 and the boundary portions 231 and d formed by the first object and the second object corresponds to about 5 to 10 mm. Even if the heating position of the heating unit 110 is spaced apart from the boundary portion 231 , the filler metal and the flux may be melted by using the high thermal conductivity of the Cu component of the first object 210 .

The heating position of the heating unit 110 may correspond to a portion of the first object 210 excluding the overlapping portion 230 . The overlapping portion 230 is a portion where the first object 210 and the second object 220 overlap, and the filler metal may be positioned in a gap between the objects formed in the overlapping portion 230 . In order to utilize the heat conduction of Cu component while being spaced apart from the overlapping portion 230 corresponding to the portion where the filler metal is distributed, the surface of the first object 210 excluding the overlapping portion 230 is located at the heating position of the heating unit 110 . may be applicable.

4 is an enlarged view along the dotted line X of the brazing object 200 shown in FIG. 1 , and is a photograph showing a heating position by the heating unit 110 according to another embodiment of the present disclosure.

According to an embodiment of the present disclosure, the first object 210 includes a Cu component and corresponds to a narrow tube having a relatively small diameter. The second object 220 corresponds to the STS pipe and corresponds to the expansion pipe having a relatively large diameter. Further, a boundary portion 231 is formed at the end of the overlapping portion 230 formed by combining the first object and the second object. The boundary portion 231 may include a junction formed in a gap between the first object 210 and the second object 220 . The joint portion includes a portion where the filler metal and the flux are melted and joined to the gap between the first object 210 and the second object 220 . A portion 232 of the bonding portion may be formed to extend from the boundary portion 231 .

The heating position of the heating unit 110 needs to be spaced apart from the boundary portion 231 formed by the first object 210 and the second object 220 to an appropriate position. According to an embodiment of the present disclosure, the heating unit 110 is spaced apart from the boundary portion 231 formed by the first object 210 and the second object 220 by about 5 to 10 mm of the first object 210 . configured to heat the surface. That is, a distance between the position D of the first object 210 heated by the heating unit 110 and the boundary portions 231 and d formed by the first object and the second object corresponds to about 5 to 10 mm. Even if the heating position of the heating unit 110 is spaced apart from the boundary portion 231 , the filler metal and the flux may be melted by using the high thermal conductivity of the Cu component of the first object 210 .

5 is a flowchart illustrating a brazing method according to an embodiment of the present disclosure.

The brazing method according to an embodiment of the present disclosure starts with the step of supplying a filler metal and a flux to the gap between the brazing objects 200 (S510). The filler metal and flux may be fed simultaneously or sequentially. The filler metal and flux may be supplied in a solid state, or some of them may be supplied in a molten state.

After that, the brazing object 200 is moved toward the heating unit 110 (S520). Alternatively, the heating unit 110 may move toward the brazing object 200 .

The heating unit 110 heats the first object 210 (S530). The heating unit 110 may be positioned on the surface of the first object spaced apart from the boundary portion 231 between the first object 210 and the second object 220 by about 5 to 10 mm. The first object 210 includes a Cu component. The gas unit 120 supplies the combustible gas to the heating unit 110 . The combustible gas supplied to the heating unit 110 corresponds to any one or a combination of acetylene, ethylene, LPG, LNG, and hydrogen. The heating unit 110 heats the surface of the first object spaced apart from the boundary portion 231 formed by the first object 210 and the second object 220 by about 5 to 10 mm. Alternatively, the heating unit 110 heats the surface of the first object except for the overlapping portion 230 .

The filler metal and the flux are melted using the heat conduction of the Cu component of the first object 210 (S540). Conventionally, when the junction of the brazing object 200 is directly heated using a torch device, a problem in which the surface of the brazing object is damaged or the oxidation rate is increased may occur. On the other hand, the brazing method in which heat is applied to the surface of the first object to melt the filler metal and the flux using Cu thermal conduction of the first object is less damaging to the surface of the brazing object including the second object, and surface oxidation can be prevented. .

At this time, since the melting point of the flux is lower than that of the filler metal, the flux is melted before the filler material, thereby preventing surface oxidation of the brazing object. Flux with a lower melting point than the filler metal melts faster at a lower temperature than the filler metal. Since the flux removes surface oxides from the stage when the heating of the filler metal and the brazing object is started by the heat conduction of the first object, the surface oxidation of the brazing object is prevented, and the corrosion resistance of the STS pipe is additionally protected, and silver (Ag ), by using filler metal that does not contain or contains less, it is possible to obtain the effect of reducing the brazing cost.

After that, the filler metal and the flux become solid to form a joint (S550).

Although the above-described steps are described as being sequentially performed, the present disclosure is not limited thereto, and some steps may be performed simultaneously.

6 is a perspective view showing a brazing apparatus 100 and a brazing object 200 according to another embodiment of the present disclosure. The brazing apparatus 100 according to an embodiment of the present disclosure may have a double tip shape in the form of the heating unit 110 . Since the heating position of the heating unit 110 overlaps with the above-described content, it will be omitted.

The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to various modifications without departing from the spirit or scope of the disclosure. Accordingly, this disclosure is not intended to be limited to the examples set forth herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Although the present disclosure has been described with reference to some embodiments herein, it should be understood that various modifications and changes may be made without departing from the scope of the present disclosure as understood by those skilled in the art to which the present disclosure pertains. something to do. Further, such modifications and variations are intended to fall within the scope of the claims appended hereto.

100: brazing device
110: heating unit
120: power unit
200: brazing object
210: first object
220: second object
230: overlapping portion
231: border

Claims (10)

As a brazing method of a brazing object comprising a first object and a second object,
supplying a filler metal and a flux to a gap between the first object and the second object;
heating the first object by a heating unit;
melting the filler metal and the flux; and
The filler metal and the flux are solidified so that the first object and the second object are combined with each other.
including,
The first object includes a Cu component,
The step of heating the first object by the heating unit,
A brazing method comprising the step of heating the surface of the first object spaced apart by 5 to 10 mm from the boundary between the first object and the object formed by the second object by the heating unit.
According to claim 1,
The brazing method further comprising the step of supplying at least one of acetylene, ethylene, LPG, LNG, and hydrogen to the heating unit.
According to claim 1,
The second object corresponds to the STS pipe, brazing method.
According to claim 1,
the melting point of the flux is lower than that of the filler metal, brazing method
5. The method of claim 4,
A melting temperature difference (ΔT) between the filler metal and the flux corresponds to 200° C. or more, a brazing method.
As a brazing method of a brazing object comprising a first object and a second object,
supplying a filler metal and a flux to a gap between the first object and the second object;
heating the first object by a heating unit;
melting the filler metal and the flux; and
The filler metal and the flux are solidified and the first object and the second object are combined with each other.
including,
The first object includes a Cu component,
The step of heating the first object by the heating unit,
Among the surfaces of the first object, heating the surface of the first object except for an overlap formed by the first object and the second object,
The melting of the filler metal and the flux comprises:
A brazing method of melting the filler metal and the flux by using heat conduction of the first object.
7. The method of claim 6,
One of the first object and the second object corresponds to an enlarged tube having a relatively large diameter, and the other corresponds to a narrow tube having a relatively small diameter,
The narrow tube is partially inserted into the expanded tube to form the overlapping portion, a brazing method.
A brazing device for heating a brazing object comprising a first object and a second object, comprising:
a heating unit configured to heat a first object including a Cu component; and
A gas unit for supplying a combustible gas to the heating unit
including,
The heating unit is configured to heat the surface of the first object 5 to 10 mm away from the boundary between the object formed by the first object and the second object, the brazing device.
A brazing device for heating a brazing object comprising a first object and a second object, comprising:
a heating unit configured to heat a first object including a Cu component; and
A gas unit for supplying a combustible gas to the heating unit
including,
The heating unit is configured to heat the surface of the first object except for the overlapping portion formed by the first object and the second object among the surfaces of the first object, and uses the heat conduction of the first object to heat the filler metal and A brazing device that melts the flux.
10. The method according to claim 8 or 9,
The heating unit corresponds to a single tip (Single Tip) or a double tip (Double Tip), brazing device.

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