KR100954055B1 - Heat exchanger with low-carbon steel parts - Google Patents

Abstract

The present invention relates to a low-carbon steel heat exchanger, a heat exchanger comprising two or more components, wherein at least one of the two or more components has a carbon content of 0.001 to 0.5% by weight of a low carbon steel base material or a carbon content of 0.001 to 0.5 weight % And a low carbon steel base material having a silicon content of 0.001 to 0.5% by weight, and a bonding material coated with an aluminum-silicon compound (Al / Si) or an aluminum-silicon-zinc compound (Al / Si / Zn) bonding material on the surface of the low carbon steel base material. And a layer, wherein the two or more components are brazed to each other via the bonding material layer.

The low carbon steel heat exchanger of the present invention is excellent in strength and has an effect of enabling the joining of the aluminum component constituting the heat exchanger and the low carbon steel component by Nocolok Brazing. In addition, the low carbon steel heat exchanger of the present invention does not change the surface color of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer during brazing because of the low carbon content of the base metal. It can replace the aluminum part of the part which does not need heat exchange, and can improve the strength of the heat exchanger part. In addition, the low-carbon steel heat exchanger of the present invention can reduce the cost by using a relatively low-cost low-carbon steel material instead of aluminum, it is possible to reduce the thickness of the parts. In addition, since the intermediate layer of aluminum-iron-silicon or aluminum-iron-silicon-zinc is formed between the low carbon steel base material and the bonding material layer during the brazing process, the corrosion of the low carbon steel base material is prevented, and the iron oxide is exposed to the exposed portion of the low carbon steel base material. A passivation layer may be formed to improve corrosion resistance.

Low Carbon Steel Heat Exchanger Parts, Side Plates, Heat Exchangers, Bonding Materials, Brazing

Description

Low Carbon Steel Heat Exchanger {HEAT EXCHANGER WITH LOW-CARBON STEEL PARTS}

The present invention relates to a low carbon steel heat exchanger, and more particularly, to a heat exchanger including two or more components, wherein at least one of the two or more components has a low carbon steel base material or carbon content having a carbon content of 0.001 to 0.5% by weight. A low carbon steel base material having 0.001 to 0.5% by weight and a silicon content of 0.001 to 0.5% by weight, and an aluminum-silicon compound (Al / Si) or an aluminum-silicon-zinc compound (Al / Si / Zn) bonding material on the surface of the low carbon steel base material. And a bonding material layer coated with each other, wherein the two or more components are brazed to each other through the bonding material layer.

Generally, heat exchangers of automobiles include heaters, coolers, evaporators, and condensers, and are used to heat or cool indoor air of vehicles, or to evaporate or condense refrigerant.

The heat exchanger is mainly made of aluminum, and brazing is performed by joining other aluminum parts by applying heat at a temperature range of 450 ° C or higher and below the melting point of the base material aluminum to the bonding material attached to the aluminum part by rolling. Formed by the method.

However, the heat exchanger component using the aluminum has a problem that the strength is low, and the cost is expensive at the portion requiring high strength and high durability.

In order to solve the above problems, a technology of brazing after coating an aluminum bonding material containing 6 to 12% of silicon or 6 to 12% of silicon and 1 to 1.5% of zinc to steel is known (US Pat. No. 5,277,358). In addition, an aluminum layer is formed on the steel, and a bonding material is coated on the aluminum layer to describe a technique of brazing (US Patent Publication No. 2005-0006066).

However, these techniques do not mention the carbon content of the steel, so if the carbon content exceeds a certain amount, when brazing the aluminum and steel in a brazing furnace, carbon in the steel diffuses to the surface of the aluminum coating layer bonding material. There is a problem in that the color is blacked without bonding due to this. In addition, the above technologies do not mention the coating thickness of the bonding material, so that if the coating thickness of the bonding material is smaller than a certain amount, there is a problem that the aluminum material may be eroded in the brazing process if the bonding amount is exceeded.

The present invention is to solve the problems of the prior art by minimizing the carbon content of the carbon steel base material, when the carbon steel base material and aluminum brazing in a brazing furnace (brazing furnace), the carbon in the base material is diffused to the aluminum bonding surface aluminum It prevents the brazing of the carbon steel and prevents the surface color from changing to black so that the carbon steel can be used in parts of the heat exchanger that require strength equivalent to 20 to 35 kg _f / mm ^{2, which} cannot be satisfied with aluminum. The purpose is to provide a low carbon steel heat exchanger employing a base material. In addition, the present invention not only satisfies the physical properties required for high strength as a material of the heat exchanger, but also provides excellent bonding and provides a certain amount of the bonding layer coating thickness to solve the erosion or lack of bonding beads in the bonding portion. The purpose is to provide a steel heat exchanger.

The object of the present invention is a heat exchanger comprising two or more components, wherein at least one of the two or more components is a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight or a carbon content of 0.001 to 0.5% by weight and a silicon content. The low carbon steel base material of 0.001 to 0.5% by weight and a bonding material layer coated with an aluminum-silicon compound (Al / Si) or an aluminum-silicon-zinc compound (Al / Si / Zn) bonding material on the surface of the low carbon steel base material. And a low carbon steel heat exchanger comprising the two or more components brazed to each other via the bonding material layer.

The thickness before brazing bonding of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding material layer coated on one surface of the low carbon steel base material is 6 to 14% of the total thickness of the part. It is characterized by 1.0 to 5.0 times thicker. In addition, the thickness after the brazing bonding of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer is thinner than before the brazing bonding, and the thickness after the brazing bonding of the interface layer is brazing. It is characterized in that it becomes thicker than before bonding.

In the heat exchanger component, the exposed portion of the low carbon steel base material may further include an iron oxide passivation layer of iron (II) oxide (FeO) or triiron tetraoxide (Fe ₃ O ₄ ).

Heat exchanger components of the present invention include a condenser header pipe, an evaporator tank, an evaporator header, a heater tank, a heater header, a charge air cooler header, a heat exchanger side plate, or a bracket.

The low carbon steel heat exchanger of the present invention has excellent strength by using a low carbon steel base material for structural parts requiring high strength such as brackets, coresides, headers and tanks of heat exchangers, and constitutes a heat exchanger by Nocolok Brazing. There is an effect of enabling the joining of aluminum parts and low carbon steel parts.

In addition, the low carbon steel heat exchanger of the present invention does not change the surface color of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer during brazing because of the low carbon content of the base metal. It can replace the aluminum part of the part which does not need heat exchange, and can improve the strength of the heat exchanger part. In addition, the low-carbon steel heat exchanger of the present invention can reduce the cost by using a relatively low-cost low-carbon steel material instead of aluminum, it is possible to reduce the thickness of the parts.

In addition, since the intermediate layer of aluminum-iron-silicon or aluminum-iron-silicon-zinc is formed between the low carbon steel base material and the bonding material layer in the brazing process, the corrosion of the low carbon steel base material is prevented and the iron oxide is exposed to the exposed portion of the low carbon steel base material. A passivation layer may be formed to improve corrosion resistance.

The low carbon steel heat exchanger of the present invention is a heat exchanger including two or more components, wherein at least one of the two or more components is a low carbon steel base material having a carbon content of 0.001 to 0.5 wt% or a carbon content of 0.001 to 0.5 wt% and silicon A low carbon steel base material having a content of 0.001 to 0.5 wt% and a bonding material layer coated with an aluminum-silicon compound (Al / Si) or an aluminum-silicon-zinc compound (Al / Si / Zn) bonding material on the surface of the low carbon steel base material. And the two or more parts brazed to each other through the bonding material layer.

The carbon steel base material constituting the part of the low carbon steel heat exchanger of the present invention is characterized by being a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight.

In the brazing method of the present invention, the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding material is coated on a low carbon steel surface as a base material, and at a brazing temperature of 550 ° C. to 630 ° C. It is a method of melting only the said bonding material and joining the low carbon steel which is a base material with another low carbon steel components or aluminum components. At this time, if the carbon content of the carbon steel base material is less than 0.001% by weight, the strength as the carbon steel is lowered, and it is difficult to manage a low amount of carbon. If the carbon content of the carbon steel base material exceeds 0.5% by weight, the structural parts of the heat exchanger When brazing a carbon steel substrate as a brazing furnace with other aluminum parts, a large amount of carbon diffuses to the surface of the bonding material layer, and consequently, the interfering force is superior to the bonding force caused by the diffusion of the aluminum and silicon bonding layer. There is a problem that the joint is not made smoothly. In addition, when the carbon content of the carbon steel base material is more than 0.5% by weight, the carbon is diffused on the surface of the bonding material, the bonding is not made and the surface color is black.

Therefore, it is possible to form a low carbon steel heat exchanger component having excellent strength and bonding and having a surface color close to that of aluminum only when a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight is used.

In addition, the carbon steel base material constituting the components of the low-carbon steel heat exchanger of the present invention is characterized in that the carbon content is 0.001 to 0.5% by weight and the silicon content is 0.001 to 0.5% by weight low carbon steel base material. When 0.001 to 0.5% by weight of silicon is added to a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight, the silicon becomes an aluminum-silicon compound (Al / Si) or an aluminum-silicon-zinc compound (Al / The diffusion of Si / Zn) into the bonding material layer is prevented to facilitate the bonding by diffusion of the aluminum and silicon bonding material layers. If the silicon content is less than 0.001% by weight in the low carbon steel base material, the silicon inhibits the diffusion of carbon less than the force of carbon diffusion into the bonding layer in the brazing bonding process. If the content exceeds 0.5% by weight, the brittleness of the carbon steel is increased to lower the physical properties of the base material. Therefore, the silicon content of the low carbon steel base material is appropriately in the range of 0.001 to 0.5% by weight.

The thickness before brazing bonding of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding material layer coated on one surface of the low carbon steel base material of the present invention is 6 It is characterized by 1.0 to 5.0 times thicker than ~ 14%. In addition, the thickness after the brazing bonding of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer is thinner than before the brazing bonding, and the thickness after the brazing bonding of the interface layer is brazing. It is characterized in that it becomes thicker than before bonding.

In general, the cladding ratio of the cladding layer is in the range of 6-14% of the overall thickness of the component when brazing the aluminum material. However, when the brazing bonding with the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer coated on the surface of the low carbon steel base material and the low carbon steel base material of the present invention, the low carbon base material Diffusion proceeds between the steel and the coated bonding material layer to grow an intermediate interface layer and the thickness of the bonding material layer formed before brazing is relatively reduced. Therefore, it is necessary to adjust the clad rate in a range different from the clad rate of the bonding material layer generally used when brazing an aluminum material. The present inventors confirmed that the appropriate thickness of the bonding material layer of the present invention through the experiment is 6.6 ~ 70% of the total thickness of the component and the thickness range of the bonding material layer is 1.1 ~ 5.0 × 6 ~ 14% of the total thickness of the component Can be represented. Specifically, when the coating thickness of the bonding material layer is too thin, that is, less than 6.6% of the total thickness of the part, the bonding beads are small and the bonding strength is poor. In addition, if the coating thickness of the bonding material layer is too thick, that is, exceeding 70% of the total thickness of the part, erosion occurs and the corresponding aluminum part is deformed or melted during brazing of the low carbon steel base part and the counterpart aluminum part. A problem occurs. Therefore, the aluminum-silicon compound (Al / Si) or aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer coated on the surface of the low carbon steel base material of the present invention is 1.1 ~ 5.0 × 6 ~ It can be defined as having a relation of 14%.

In the aluminum-silicon compound bonding material of the present invention, the silicon content is not particularly limited, but in order to increase the strength of the bond and effectively block carbon diffusion of low carbon steel, the silicon content is preferably 6 to 15% by weight. In the aluminum-silicon-zinc compound (Al / Si / Zn) bonding material of the present invention, the zinc is an element used to supplement the corrosion resistance of the bonding material layer. In the aluminum-silicon-zinc compound (Al / Si / Zn) bonding material of the present invention, the zinc content is not particularly limited, but the zinc content is preferably 0.01 to 4% by weight in consideration of the effect of corrosion resistance and economical efficiency by zinc addition. .

The low carbon steel heat exchanger component of the present invention may further include an iron oxide passivation layer of iron oxide (II) (FeO) or triiron tetraoxide (Fe ₃ O ₄ ) at an exposed portion of the low carbon steel base material. The low carbon steel heat exchanger component of the present invention is iron (II) oxide (FeO) or trioxide, which is a passivation film formed on the surface of the low carbon steel exposed to the outside in the brazing process in the brazing temperature range of 500 to 600 ℃ and the moisture atmosphere. An iron oxide passivation layer (Fe ₃ O ₄ ) may be included, and the passivation layer serves to complement corrosion resistance of the low carbon steel component. Here, the passivation layer of the iron oxide may be applied to the side plate or bracket in which one side or both sides of the low carbon steel heat exchanger component is exposed to the corrosive environment. In addition, a component in which the bonding material is rolled and bonded the low carbon steel, such as a condenser header pipe or an evaporator header, may form the passivation layer of iron oxide by solid solution of the low carbon steel in the exposed cross section.

1A is a schematic representation of a low carbon steel heat exchanger component of the present invention using an aluminum-silicon compound (Al / 6-15% Si) bonding material and a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight.

As shown in Figure 1a, when the coating of the aluminum-silicon compound (Al / 6 ~ 15% Si) bonding material on the low carbon steel base material and brazing after the low carbon steel base material and aluminum-silicon bonding material coating layer diffusion during the brazing process Since many / Fe / Si layers are formed, it can be seen that the aluminum-silicon bonding layer is relatively reduced. In addition, when a cross section of a low carbon steel base material such as a side plate of the heat exchanger part is exposed to air, iron (II) (FeO) (FeO), which is a passivation film on the surface of the carbon steel during the brazing process in a temperature range of 500 to 600 ° C. and a moisture atmosphere. ) Or iron oxide passivation layer of triiron tetraoxide (Fe ₃ O ₄ ) is formed, it can be seen that the passivation layer complements the corrosion resistance of the heat exchanger components.

Unlike in FIG. 1A, when the carbon content of the carbon steel base material exceeds 0.5%, carbon of the carbon steel diffuses to the surface of the bonding material layer during the brazing bonding process, and the diffused carbon prevents the aluminum-silicon component of the bonding material from diffusing and bonding. There arises a problem that the joining of the part and the other aluminum part or the low carbon steel part cannot be made, and the surface color of the joining material layer becomes black. In addition, when silicon is included in the range of 0.001 to 0.5% by weight in the low carbon steel base material, it can prevent the carbon of the carbon steel to diffuse into the bonding material layer.

1b schematically illustrates a low carbon steel heat exchanger component of the present invention using an aluminum-silicon-zinc compound (Al / 6-15% Si / 0.01-4% Zn) bonding material and a low carbon steel base material having a carbon content of 0.001 to 0.5% by weight. It is a figure shown. 1B is the same as the content of FIG. 1A. In addition, in FIG. 1B, zinc, which is one of the components of the bonding material, is an element used to compensate for corrosion resistance of the bonding material layer.

The low carbon steel heat exchanger parts of the present invention are preferably condenser header pipes, evaporator tanks, evaporator headers, heater tanks, heater headers, charge air cooler headers, side plates, or brackets of automotive and household heat exchanger parts. It can be applied to the bracket. However, it is not limited to the said specific component.

The low carbon steel heat exchanger part according to the present invention has a strength of 2 to 5 times compared to that of a general aluminum material heat exchanger, so that the thickness can be reduced to 0.2 to 0.5 times at the same strength, thereby making it thinner. In addition, material prices can be reduced from 1/4 to 1/5.

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

Example  One : Brazing  Of low-carbon steel heat exchanger components before and after joining SEM Of EDS  analysis

A low-carbon steel base material containing 0.5 wt% carbon is coated with an aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15 wt%, and the cross-section before and after brazing bonding is performed by scanning electron microscope (SEM) and energy dispersion. The change of the bonding material layer was observed by analyzing by energy dispersive x-ray spectroscopy (EDS).

2 is a scanning electron microscope (SEM) photograph before brazing bonding of a low carbon steel heat exchanger component according to the present invention.

3A and 3B are energy dispersive x-ray spectroscopy (EDS) elemental analysis results of component analysis of the low carbon steel heat exchanger component of FIG. 2.

As shown in Figure 2, it was confirmed through the SEM picture that the bonding material is coated in a predetermined thickness on the low carbon steel base material. The layer labeled "1" is a coated bonding material layer of about 43 占 퐉, and the layer labeled "2" is an interfacial layer of about 4 占 퐉, the component of which is changed by bonding the base material carbon steel and the bonding material. Here, as shown in FIGS. 3A and 3B, the bonding material layer has a silicon content of 15%, but the silicon content decreases and the iron component is included toward the interfacial layer (aluminum-iron-silicon layer). The layer is believed to be formed by interdiffusion of a certain component between the low carbon steel and the bonding material to a lesser extent.

4 is a scanning electron microscope (SEM) photograph after brazing bonding of a low carbon steel heat exchanger component according to the present invention.

5A, 5B, and 5C are energy dispersive x-ray spectroscopy (EDS) elemental analysis results of component analysis of the low carbon steel heat exchanger component of FIG. 4.

As shown in FIG. 4, diffusion between the low carbon steel and the aluminum-silicon compound (Al / Si) bonding material continued during brazing bonding, such that the aluminum-iron-silicon intermediate interface layer (“2” and “3” in FIG. 4) was 31 at 4 μm. Rather, it was confirmed that the aluminum-silicon bonding layer (“1” in FIG. 4) greatly decreased from 43 μm before brazing to 9-10 μm after brazing.

From the results of Example 1, it was concluded that the thickness of the aluminum-silicon compound (Al / Si) bonding layer of the low carbon steel heat exchanger component should be formed in consideration of the decrease in the bonding layer during the brazing process. Considering the erosion caused by erosion, the thickness of the cladding layer, which is generally used when brazing aluminum materials, is 1.1 to 5.0 times higher than the range of 6-14% of the total thickness of the component. 6.6 ~ 70% of the total thickness) was confirmed through the experiment. Therefore, the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer of the present invention has a relation of 1.1 to 5.0 × 6 to 14% of the total thickness of the low carbon steel heat exchanger component. It can be defined as having.

Comparative example  1: Observation of the surface color of carbon steel heat exchanger parts with a carbon content of 0.7 wt% (greater than 0.5 wt%)

An aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15% by weight was coated on a carbon steel material having a carbon content of 0.7% by weight on both sides, and a brazing connection with a counterpart heat exchanger aluminum fin was attempted. This did not go smoothly.

FIG. 6 is a photograph showing the surface color of the bonding material layer when the bonding material is coated and brazed on a carbon steel base material having a carbon content of 0.7 wt%. FIG. When the carbon content of the carbon steel base material exceeds 0.5% by weight, it can be seen that during the brazing bonding process, a large amount of carbon in the base material diffuses to the surface of the aluminum-silicon compound (Al / Si) bonding material layer and the surface of the bonding material layer turns black.

Example  2: Observation of surface color of low carbon steel heat exchanger parts with carbon content of 0.5% by weight

An aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15% by weight was coated on a carbon steel material having a carbon content of 0.5% by weight, and brazing bonding was performed with a counterpart heat exchanger aluminum fin.

7A and 7B are photographs showing the surface color of the low carbon steel heat exchanger component according to the present invention after coating a brazing material on a carbon steel having a carbon content of 0.5% by weight and brazing bonding. When the aluminum-silicon bonding material is coated on the surface of the low carbon steel base material having a carbon content of 0.5 wt% as shown in FIGS. 7A and 7B and the brazing bonding is performed, carbon does not diffuse to the surface of the bonding material layer during the brazing bonding. The surface color was similar to that of aluminum, and the bonding was smooth without the influence of the counterpart aluminum component and carbon.

Example  3: Observation of the junction with the fin of the heat exchanger part

An aluminum fin was brazed and bonded to a low carbon steel heat exchanger component coated with an aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15% by weight in a carbon steel material having a carbon content of 0.5% by weight.

FIG. 8A is a photograph showing a bonding interface after brazing bonding aluminum fins to a conventional aluminum heat exchanger component, and FIG. 8B is a photograph showing a bonding interface after brazing bonding aluminum fins to a low carbon steel heat exchanger component of the present invention. When brazing bonding the aluminum fin to the low carbon steel heat exchanger component of the present invention as shown in FIG. 8B, the bonding interface had a bonding bead almost corresponding to the brazing bonding interface between the conventional aluminum component and the aluminum fin of FIG. Was good.

9 is a photograph of the adhesion test between the low-carbon steel component coated with the aluminum silicon bonding material according to the present invention and the aluminum fin bonded to the low-carbon steel component. As a result of testing the adhesion between the low carbon steel heat exchanger component and the fin as shown in Figure 9 it can be seen indirectly that the bonding bead is good enough to tear the fin without being separated.

Example  4: heat exchanger made of low carbon steel heat exchanger parts with carbon content of 0.5% by weight

(1) A carbon-containing 0.5 wt% low carbon steel base material was coated with an aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15 wt%, and braze-bonded with a counterpart aluminum component to produce a heat exchanger.

10 is a photograph showing a vehicle heat exchanger condenser product brazing the side plate which is a low carbon steel heat exchanger component according to the present invention. As shown in FIG. 10, the heat exchanger using the low carbon steel heat exchanger component was thinner than the heat exchanger using aluminum as the base material, and the surface color did not change to the aluminum color, and the strength was further increased.

(2) A 0.5-wt% carbon-based low carbon steel base material coated with an aluminum-silicon or aluminum-silicon-zinc compound (Al / Si / Zn) bonding material having a silicon content of 15 wt% and a zinc content of 4 wt%. The heat exchanger was manufactured by brazing the aluminum parts.

11A is a picture showing a charge air cooler heat exchanger brazed to a low carbon steel heat exchanger component according to the present invention, and FIG. 11B is a heater heat exchanger brazed to a low carbon steel heat exchanger component according to the present invention. It is a photograph. 11A and 11B, the heat exchanger using the low carbon steel heat exchanger component was thinner than the heat exchanger using aluminum as the base material, and the surface color did not change to the aluminum color, and the strength was further increased.

As shown in FIG. 10, the heat exchanger using the low carbon steel heat exchanger component was thinner than the heat exchanger using aluminum as the base material, and the surface color did not change to the aluminum color, and the strength was further increased.

Example  5: On the exposed surface of low carbon steel heat exchanger parts with a carbon content of 0.5% by weight Passive  formation

The counterpart was brazed to a low carbon steel heat exchanger component coated with a carbon-based material having a carbon content of 0.5% by weight and an aluminum-silicon compound (Al / Si) bonding material having a silicon content of 15% by weight. Thereafter, it was observed whether the passivation was formed in the exposed portion of the low carbon steel in which the aluminum-silicon compound (Al / Si) bonding material was not coated in the low carbon steel base material having a carbon content of 0.5 wt%.

12 is a photograph in which passivation is formed when brazing a low carbon steel heat exchanger component according to the present invention. As shown in FIG. 12, a black or black passivation layer of iron oxide (II) (FeO) or triiron tetraoxide (Fe ₃ O ₄ ) was formed under brazing bonding conditions.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Figure 1a is a schematic view of the low carbon steel heat exchanger component according to the present invention.

2 is a scanning electron microscope (SEM) photograph before brazing bonding of a low carbon steel heat exchanger component according to the present invention.

3A and 3B are energy dispersive x-ray spectroscopy (EDS) elemental analysis results of component analysis of the low carbon steel heat exchanger component of FIG. 2.

4 is a scanning electron microscope (SEM) photograph after brazing bonding of a low carbon steel heat exchanger component according to the present invention.

5A, 5B and 5C are energy dispersive x-ray spectroscopy (EDS) elemental analysis results of component analysis of the low carbon steel heat exchanger component of FIG. 4.

FIG. 6 is a photograph showing the surface color of the bonding material layer when the bonding material is coated and brazed on a carbon steel base material having a carbon content of 0.7 wt%. FIG.

7a and 7b is a photograph showing the surface color after coating the bonding material on the carbon steel having a carbon content of 0.5% by weight of the side plate, a low carbon steel heat exchanger component according to the present invention.

FIG. 8A is a photograph showing a bonding interface after brazing bonding aluminum fins to a conventional aluminum heat exchanger component, and FIG. 8B is a photograph showing a bonding interface after brazing bonding aluminum fins to a low carbon steel heat exchanger component of the present invention.

9 is a photograph of the adhesion test between the low-carbon steel component coated with the aluminum silicon bonding material according to the present invention and the aluminum fin bonded to the low-carbon steel component.

10 is a photograph showing a vehicle heat exchanger condenser product brazing the side plate which is a low carbon steel heat exchanger component according to the present invention.

11A is a picture showing a charge air cooler heat exchanger brazed to a low carbon steel heat exchanger component according to the present invention, and FIG. 11B is a heater heat exchanger brazed to a low carbon steel heat exchanger component according to the present invention. It is a photograph.

12 is a photograph in which passivation is formed when brazing a low carbon steel heat exchanger component according to the present invention.

Claims (5)

A heat exchanger comprising two or more parts, At least one of the two or more components includes a low carbon steel base material having a carbon content of 0.001 to 0.5 wt% or a low carbon steel base material having a carbon content of 0.001 to 0.5 wt% and a silicon content of 0.001 to 0.5 wt%, and the low carbon steel base material. It includes a bonding material layer coated on the surface of the aluminum-silicon compound (Al / Si) or aluminum-silicon-zinc compound (Al / Si / Zn) bonding material, A low carbon steel heat exchanger comprising the two or more parts brazed to each other via the bonding material layer. According to claim 1, wherein the thickness before the brazing bonding of the aluminum-silicon compound (Al / Si) or aluminum-silicon-zinc compound (Al / Si / Zn) bonding material layer coated on one surface of the low carbon steel base material, Low carbon steel heat exchanger, characterized in that 1.0 to 5.0 times thicker than 6 to 14% of the thickness. The thickness after the brazing bonding of the aluminum-silicon compound (Al / Si) or the aluminum-silicon-zinc compound (Al / Si / Zn) bonding layer is thinner than before the brazing bonding, and the brazing bonding of the interface layer. The thickness after heat becomes thicker than before brazing joining. The low carbon steel heat exchanger of claim 1, further comprising an iron oxide passivation layer of iron oxide (II) (FeO) or triiron tetraoxide (Fe ₃ O ₄ ) at an exposed portion of the low carbon steel base material of the component. 4. The component of claim 1, wherein the part is a condenser header pipe, an evaporator tank, an evaporator header, a heater tank, a heater header, a charge air cooler header, a heat exchanger side plate, or a bracket. Low carbon steel heat exchanger.

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