KR20180074417A - Manufacturing method of multi-layered sheet - Google Patents

Abstract

A method for manufacturing a multilayer plate according to the present invention comprises: a step for preparing a first plate, a second plate and a third plate, and pre-treating the first plate to the third plate; a first heat treatment step for heat treating each of the first to third plates; a step for stacking and rolling the first to third plates to form a multilayer plate; and a second heat treatment step for heat treating the multilayer plate. According to the present invention, a multilayer plate having enhanced corrosion resistance and strength can be provided.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a multi-

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a multilayer plate material in which a plurality of metal plate materials are laminated, and more particularly, to a method of manufacturing a multilayer plate material including titanium.

Generally, a multilayer plate material (or a clad material) is defined as a laminate type composite material in which two or more surfaces of metal materials are metallurgically bonded and integrated. Such a multilayer sheet material is economically advantageous because it can maximize the performance of the material and save expensive materials by appropriately combining various materials.

Accordingly, the combination of the materials used in the production of the multi-layered sheet material has been diversified and its application field has also been expanded.

The materials of the multi-layered plate are various, but in most cases, they are high-functional materials which do not deteriorate even under harsh environments such as a corrosive atmosphere, and their price is also high. Double titanium is a light, strong and corrosion-resistant metal, but its application is limited because it is considerably more expensive than other metal materials. It is used in some applications such as seawater desalination and shipbuilding heat exchangers and building exterior materials .

In order to solve this problem, a multi-layered plate joining titanium and dissimilar metals has been produced in order to manufacture the titanium at a low cost while ensuring excellent physical properties.

However, the bonding property between titanium and the dissimilar metal is disadvantageously detached after molding.

Accordingly, the present invention provides a method for producing a multilayer sheet material having excellent bonding properties.

A method of manufacturing a multilayer plate according to an embodiment of the present invention includes the steps of preparing a first plate, a second plate, and a third plate, pretreating the first plate to the third plate, A first heat treatment step in which heat treatment is performed, a step of laminating the first to third plates and rolling to form a multi-layered plate, and a second heat treatment step of heat-treating the multi-layered plate.

In the pretreatment step, the roughness of the second plate member can be made larger than the roughness of the first plate member and the third plate member.

The first plate and the third plate may be a titanium plate, and the second plate may be an aluminum plate or an aluminum alloy plate.

In the first heat treatment step, the second plate may proceed at 200 ° C to 400 ° C for 10 minutes or less.

In the first heat treatment step, the first plate and the third plate may proceed at 200 ° C to 300 ° C for 10 minutes or less.

In the second heat treatment step, the multi-layer plate may be heated at 200 ° C to 300 ° C for 30 minutes or more.

Wherein the aluminum sheet material contains 0.4% or less of iron and 0.25% or less of silicon (Si), and the aluminum alloy sheet material may contain 1% to 1.5% of manganese (Mn), 0.7% or less of iron and 0.6% have.

The thickness of the first plate and the third plate may be thinner than the thickness of the second plate.

In the pretreatment step, the surface of the first plate, the second plate, and the third plate may be subjected to a brushing process and a sandblasting process to form the unevenness.

As described in the present invention, it is possible to provide a multi-layered plate having improved corrosion resistance and strength by improving the bonding properties between the multi-layered plates.

In addition, it can be used as a metal plate for a heat exchanger which requires heat transfer characteristics by improving the heat transfer characteristic of a titanium plate material.

1 is a schematic cross-sectional view of a multi-layered sheet according to an embodiment of the present invention.
2 is a flowchart illustrating a method of forming a multi-layered sheet according to an embodiment of the present invention.
3 is a cross-sectional photograph of a multi-layer plate according to an embodiment of the present invention.
4 and 5 are photographs of a multi-layer plate material according to an embodiment of the present invention.
6 and 7 are photographs showing the corrosion resistance of the multilayer plate according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In addition, since the sizes and thicknesses of the respective components shown in the drawings are arbitrarily shown for convenience of explanation, the present invention is not necessarily limited to those shown in the drawings.

In the drawings, the thicknesses are enlarged to clearly indicate layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated. Whenever a portion such as a layer, film, region, plate, or the like is referred to as being "on" or "on" another portion, it includes not only the case where it is "directly on" another portion but also the case where there is another portion in between.

Also, throughout the specification, when an element is referred to as "including" an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. Also, throughout the specification, the term "on " means to be located above or below a target portion, and does not necessarily mean that the target portion is located on the image side with respect to the gravitational direction.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the drawings.

1 is a schematic cross-sectional view of a multi-layered sheet according to an embodiment of the present invention.

As shown in FIG. 1, a multilayer plate 100 according to an embodiment of the present invention includes a first plate 12, a second plate 14, and a third plate 16 stacked thereon.

The second plate member 14 is located between the first plate member 12 and the third plate member 16 and joins them therebetween.

Specifically, the first plate 12 and the third plate 16 may be a plate containing titanium, and the second plate 14 may be a plate containing aluminum.

The first plate 12 and the third plate 16 are made of a pure titanium plate material and may contain not more than 0.2% iron (Fe) and not more than 0.18% oxygen (O). At this time, the first plate 12 and the third plate 16 may have a thickness of 0.2 mm to 0.3 mm and a width of 500 mm or more and 1,250 mm or less.

The second plate 14 is made of a pure aluminum plate, and may contain 0.4% or less iron and 0.25% or less silicon (Si). Or the second plate 14 is an aluminum alloy with increased strength, and may contain 1% to 1.5% of manganese (Mn), 0.7% or less of iron, and 0.6% or less of silicon. At this time, the thickness of the aluminum plate material may be 0.5 mm to 2.0 mm, and the width may be 500 mm or more and 1,250 mm or less. When an aluminum alloy is used, the tensile strength of the multi-layered sheet may be 100 MPa to 400 MPa.

Hereinafter, a method of forming the multilayer sheet material shown in FIG. 1 will be described with reference to the drawings.

2 is a flowchart illustrating a method of forming a multi-layered sheet according to an embodiment of the present invention.

Referring to FIG. 2, a method of forming a multi-layer plate according to an embodiment of the present invention includes a step of pre-treating a first plate to a third plate (S100), a step of performing a first heat treatment of the first plate to the third plate Step S104 of laminating the first to third plates, rolling the first to third plates, and performing a second heat treatment of the first to third plates (S106).

The step (S100) of pretreating the first to third plates is to remove the contamination on the surfaces of the first to third plates, and the surface is washed with an organic solvent. At this time, the organic solvent may be alcohol-based, for example, methyl alcohol or acetone. And the first plate and the third plate may be titanium sheets.

Thereafter, irregularities are formed on the surfaces of the first to third plates. The unevenness can be carried out once by a mechanical process such as brushing using a steel brush or sandblasting. Through such a mechanical process, the surface roughness can be increased by breaking the oxide film formed on the surfaces of the first plate and the third plate and simultaneously forming concave and convex portions.

At this time, since the thickness of the first plate and the third plate is thinner than the thickness of the second plate, the surface of the second plate is made rougher than the first plate and the third plate. Therefore, the concavities and convexities of the first and third plates can be larger than the concavities and convexities of the second plate. This can be modified by controlling the strength of the brush during the brushing process, the pressure during the sandblasting process and the particle size.

The first plate and the third plate may form concavities and convexities only on one surface facing the second plate. Since the second plate is disposed between the first plate and the third plate, concave and convex are preferably formed on both surfaces.

The first step to the third step (S102) of heat treating the first to third plates is for preheating the first to third plates. The first and third plates are heat-treated at 200 ° C to 300 ° C for 10 minutes or less , And the second plate is heat-treated at 200 ° C to 400 ° C for 10 minutes or less. On the other hand, in the case of titanium, the preheating process can be omitted since it has a relatively thin thickness compared to aluminum. Further, titanium is subjected to heat treatment at a temperature of 300 DEG C or less because it is discolored at a high temperature exceeding 300 DEG C.

In the rolling step (S104), the first plate, the second plate, and the third plate are stacked in order and rolled by a rolling mill. Further, the rolling can be performed by first rolling the first plate and the second plate, then second rolling the laminate after the third plate is laminated.

At this time, the reduction rate is maintained at least 30% for securing the bonding strength.

In the second heat treatment step (S106), the multi-layer plate material formed by rolling is heat-treated at 200 ° C to 300 ° C for 30 minutes or more. This is to increase the bonding strength between the first plate and the second plate and between the second plate and the third plate by the diffusion annealing process due to diffusion.

When the multi-layered sheet material is formed as in the present invention, it is possible to provide a sheet material having increased bonding force between the multi-layered sheet materials.

Table 1 is a table showing conditions at the stage of producing the multi-layer plate according to the embodiment of the present invention.

Process conditions Inventory 1 Inventory 2 The material of the second plate 1050 Al 3003 Al The first plate and the third thickness 0.2mm 0.2mm Thickness of the second plate 1.5mm 1.5mm The first heat treatment temperature of the first plate and the third plate Room temperature (no preheating) 200 ℃ The first heat treatment temperature of the second plate 300 ° C 300 ° C Feed speed of sheet material 10 m / min 10 m / min Reduction rate 50% 40% Second heat treatment temperature 200 ℃ 200 ℃ Second heat treatment time 30 minutes 30 minutes

3 is a cross-sectional photograph of a multi-layer plate according to an embodiment of the present invention.

At this time, the multilayer sheet material of FIG. 3 is a multilayer sheet material formed under the conditions of Example 1 of [Table 1].

3, the thicknesses of the first plate and the third plate in the multilayer plate according to Example 1 were 0.15 mm and 0.9 mm, respectively, and the thickness of the second plate was 0.9 mm. Further, it can be confirmed that there is no gold surface product at the interface between the first plate and the second plate and between the second plate and the third plate. This was the same in the rolling direction of the multilayer plate material shown in Fig. 1 and the cross-sectional view (not shown) cut at 90 degrees with respect to the rolling direction.

4 and 5 are photographs of a multi-layer plate material according to an embodiment of the present invention.

Fig. 4 is a photograph of an outer side when the multilayer plate of Example 1 is bent so as to have a radius of curvature of 6.0, 3.0 and 1.5, and Fig. 5 is a photograph of a cross section of the molded article of Fig.

Referring to FIG. 4, it was confirmed that no orange peel or crack was observed on the outer surface even if the R value decreased. Referring to FIG. 5, no separation or cracks were observed at the interface between the aluminum sheet and the titanium sheet even if the R value was reduced.

As described above, when the multi-layer plate is formed as in the embodiment of the present invention, the bonding force between the plate materials is increased, and the formability using the multi-layer plate is improved.

6 and 7 are photographs showing the corrosion resistance of the multilayer plate according to the present invention.

6 and 7, the corrosion products were removed after holding the multilayer plate of Example 1 for 3,000 hours in a salt spray atmosphere having a concentration of 5% NaCl, about 35 degrees, and a pH of 6.5 to 7.2. FIG. 6 is a photograph of the surface after the corrosion resistance test, and FIG. 7 is a photograph of a cross section taken with time. The photographs were taken before the experiment, 500 hours, 2,000 hours and 3,000 hours after the experiment.

Referring to FIG. 6, it can be confirmed that no corrosion occurs on the surface of the titanium plate, which is the surface of the multilayer plate according to the first embodiment.

Referring to FIG. 7, after 500 hours, the titanium plate material among the titanium plate material / aluminum plate material / titanium plate material did not exhibit the corrosion behavior, and only the aluminum plate material started to show corrosion. Even after 2,000 hours, only the aluminum plate was corroded and the depth of corrosion was about 2 mm.

Exposure time Corrosion loss (g / m ² h) 500 hours 0.027 1,000 hours 0.054 2,000 hours 0.056 3,000 hours 0.054

Table 2 shows the corrosion reduction values (g / m ² h), which shows the degree of corrosion with time (the reduction due to corrosion at a constant area per unit time). Referring to Table 2, it can be seen that, even if the time is increased due to the exposure to the corrosive environment, the corrosion reduction amount is not increased further after 1,000 hours exposure and is maintained constant up to 3,000 hours, and the depth of corrosion is not as large as 4 mm .

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the spirit and scope of the following claims. Those who are engaged in the technology field will understand easily.

12: First plate
14: Second plate
16: Third plate

Claims (9)

Preparing a first plate, a second plate and a third plate, pretreating the first plate to the third plate,
A first heat treatment step of heat-treating the first plate to the third plate,
Laminating the first to third plates and then rolling to form a multi-layered plate;
A second heat treatment step of heat-treating the multi-layer plate material
Lt; / RTI > The method of claim 1,
In the pretreatment step,
Wherein a roughness of the second plate material is larger than a roughness of the first plate material and the third plate material. 3. The method of claim 2,
Wherein the first plate and the third plate are titanium plates,
Wherein the second plate is an aluminum plate or an aluminum alloy plate. 4. The method of claim 3,
In the first heat treatment step,
Wherein the second plate is heated to 200 to 400 DEG C for 10 minutes or less. 5. The method of claim 4,
In the first heat treatment step,
Wherein the first plate and the third plate proceed at 200 캜 to 300 캜 for 10 minutes or less. 4. The method of claim 3,
In the second heat treatment step,
Wherein the multi-layer plate material is heated at a temperature of 200 to 300 DEG C for 30 minutes or more. 4. The method of claim 3,
Wherein the aluminum sheet material contains 0.4% or less of iron and 0.25% or less of silicon (Si)
Wherein the aluminum alloy sheet material contains 1% to 1.5% of manganese (Mn), 0.7% or less of iron, and 0.6% or less of silicon. The method of claim 1,
Wherein the thickness of the first plate and the third plate is thinner than the thickness of the second plate. The method of claim 1,
In the pretreatment step,
Wherein the surface of the first plate, the second plate and the third plate is formed by a brushing process and a sandblasting process.

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