JP7462292B2 - Metal foil manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing metal foil that does not cause wrinkles, unevenness, etc.

Metal foil is very thin, so wrinkling is an issue. To prevent wrinkling when the metal foil is attached to an object, a technique is known in which a large number of pores are provided in the metal foil (see, for example, Patent Document 1).

JP 2012-116069 A

However, wrinkles can occur in metal foil even immediately after production, so it is essential to prevent wrinkles from occurring at this stage in the first place. Conventionally, metal foil was produced by rolling a metallic material using rolling rollers to make it thinner. When the metal foil emerged from the rolling rollers, it had wrinkles and unevenness on its surface.

The present invention takes into consideration the above-mentioned conventional techniques, and aims to provide a method for manufacturing metal foil that can eliminate wrinkles that occur after rolling and obtain metal foil with a smooth surface.

To achieve the above object, the present invention provides a method for manufacturing metal foil, comprising a rolling step of rolling a material made of a metal material to form a sheet having a non-smooth surface with wrinkles or irregularities on the surface, a clamping step of sandwiching the non-smooth surface sheet between a high thermal expansion metal body having a higher thermal expansion coefficient than the metal material forming the non-smooth surface sheet and a low thermal expansion metal body having a lower thermal expansion coefficient than the metal material forming the non-smooth surface sheet to form a treated body, and a surface treatment step of heating the treated body to remove the wrinkles or irregularities on the surface of the non-smooth surface sheet.

Preferably, in the clamping process, the high thermal expansion metal body is cylindrical or columnar, the non-smooth surface sheet is wrapped around the high thermal expansion metal body, and the low thermal expansion metal body is further wrapped around the outside of the sheet.

Preferably, in the clamping process, the high thermal expansion coefficient metal body and the low thermal expansion coefficient metal body are in the shape of a flat plate having a thickness greater than that of the non-smooth surface sheet.

Preferably, the metal material is titanium nickel, the high thermal expansion metal body is stainless steel, and the low thermal expansion metal body is titanium, and the workpiece is heated to 100°C or higher and 700°C or lower in the surface treatment process.

According to the present invention, the workpiece heated in the surface treatment process is pressed from one side against the uneven surface sheet that constitutes the workpiece by a high thermal expansion metal body having a high thermal expansion coefficient, and is not pressed from the other side, the low thermal expansion metal body, which has a lower thermal expansion coefficient than the uneven surface sheet. In other words, since the uneven surface sheet is pressed only from one direction, any wrinkles or irregularities that have occurred are efficiently stretched and removed.

In addition, by forming the high thermal expansion metal body into a cylindrical or columnar shape and wrapping the non-smooth surface sheet and the low thermal expansion metal body around it, the non-smooth surface sheet can be pressed more uniformly, and any wrinkles or irregularities that may have occurred can be efficiently removed.

In addition, by making the high thermal expansion coefficient metal body and the low thermal expansion coefficient metal body into a flat plate shape that is thicker than the non-smooth surface sheet, the clamping operation in the clamping process becomes easier, improving handleability.

In addition, by using titanium-nickel as the metal material, stainless steel as the metal body with a high thermal expansion coefficient, and titanium as the metal body with a low thermal expansion coefficient, and setting the heating temperature in the surface treatment process to 100°C or higher and 700°C or lower, the difference in thermal expansion coefficients can be fully utilized to press the sheet with an uneven surface.

1 is a flowchart of a method for producing a metal foil according to the present invention. FIG. FIG. FIG. FIG. 11 is an explanatory diagram of another surface treatment process.

As shown in FIG. 1, the method for producing metal foil according to the present invention first involves a rolling step (step S1). This rolling step involves rolling a metal material to form a sheet with a non-smooth surface, which has wrinkles or irregularities on the surface. This is the usual method of producing metal sheets, in which the material is pressed with a rolling roller or the like to make it thinner. The metal sheet obtained here has wrinkles and irregularities on the surface, and the surface is not smooth. In other words, it does not look very good.

Next, a clamping process is carried out (step S2). This clamping process is a process in which the rough-surfaced sheet is sandwiched between a high-thermal expansion metal body having a higher thermal expansion coefficient than the metal material forming the rough-surfaced sheet and a low-thermal expansion metal body having a lower thermal expansion coefficient than the metal material forming the rough-surfaced sheet to form the treated object. That is, a high-thermal expansion metal body having a higher thermal expansion coefficient than the raw material is prepared, and a low-thermal expansion metal body having a lower thermal expansion coefficient than the raw material is prepared. The rough-surfaced sheet obtained in the rolling process is then sandwiched between these. The rough-surfaced sheet sandwiched between the high-thermal expansion metal body and the low-thermal expansion metal body becomes the treated object.

Next, a surface treatment step is performed (step S3). This surface treatment step is a step of heating the object to remove wrinkles or unevenness occurring on the surface of the non-smooth surface sheet. Specifically, the object to be treated is placed in a heating furnace or the like and heated. At this time, as the object to be treated is heated, the non-smooth surface sheet constituting the object to be treated is pressed from one side by a high thermal expansion coefficient metal body having a high thermal expansion coefficient against the non-smooth surface sheet constituting the object to be treated. Since the low thermal expansion coefficient metal body has a lower thermal expansion coefficient than the non-smooth surface sheet, the non-smooth surface sheet is not pressed from the low thermal expansion coefficient metal body on the other side. Therefore, the non-smooth surface sheet is pressed only from one direction, so that the wrinkles or unevenness occurring are efficiently stretched and removed. If pressed from both sides, different pressing portions will occur, and further wrinkles and the like will occur. However, the non-smooth surface sheet is not pressed from only one direction, but the low thermal expansion coefficient metal body acts as a pressure from the other side, contributing to forming a smooth surface for the non-smooth surface sheet. In this way, the wrinkles or irregularities on the surface of the non-smooth sheet are removed, turning it into metal foil.

As shown in FIG. 2, the high thermal expansion metal body 1 used in the clamping process has a cylindrical or columnar shape (cylindrical shape in the figure). In the clamping process, the non-smooth surface sheet 2 and the low thermal expansion metal body 3 obtained in the rolling process are also prepared. In this case, the low thermal expansion metal body 3 is a sheet shape with a similar thickness to the non-smooth surface sheet 2. However, the length of the low thermal expansion metal body 3 is longer than the non-smooth surface sheet 2. Then, as shown in FIG. 3, the non-smooth surface sheet 2 obtained in the rolling process is wrapped around the high thermal expansion metal body 1. Furthermore, the low thermal expansion metal body 3 is wrapped around it from the outside. At this time, since the low thermal expansion metal body 3 is longer than the non-smooth surface sheet 2, the entire non-smooth surface sheet 2 is reliably covered. The non-smooth surface sheet 2 and the low thermal expansion metal body 3 are fixed to the high thermal expansion metal body 1, for example, by a clip not shown. In this way, the high thermal expansion metal body 1, the non-smooth surface sheet 2, and the low thermal expansion metal body 3 are integrated to become the treated body 4. If the workpiece 4 in this state is heated in the next surface treatment process, the sheet 2 with the non-smooth surface can be pressed more uniformly, and any wrinkles or irregularities that have occurred can be efficiently removed.

As shown in FIG. 4, as a method of forming another treated object 4, the high thermal expansion metal body 1 and the low thermal expansion metal body 3 used in the clamping process may be formed into a flat plate shape with a thickness greater than that of the non-smooth surface sheet 2. In this case, the high thermal expansion metal body 1 and the low thermal expansion metal body 3 have a larger surface area than the non-smooth surface sheet 2. This allows them to be clamped while covering the entire non-smooth surface sheet 2. Furthermore, by forming the high thermal expansion metal body 1 and the low thermal expansion metal body 3 into a flat plate shape, the clamping operation in the clamping process is easier to perform, improving handling. As shown in FIG. 5, the treated object 4 formed in this way has an approximately rectangular parallelepiped shape, so that it is space-efficient when placed in a heating furnace or the like in the subsequent surface treatment process.

As described above, the high thermal expansion metal body 1 may be any metal having a higher thermal expansion coefficient than the non-smooth surface sheet 2, and the low thermal expansion metal body 3 may be any metal having a lower thermal expansion coefficient than the non-smooth surface sheet 2. Preferably, the metal material forming the non-smooth surface sheet 2 is titanium nickel, the metal forming the high thermal expansion metal body 1 is stainless steel, and the metal forming the low thermal expansion metal body 3 is titanium. The thermal expansion coefficients of these metals at 100°C are 10% for titanium nickel, 16.3% for stainless steel, and 8.4% for titanium. It has been confirmed that such a difference in thermal expansion coefficient makes the metal foil look good and gives it a mirror-like surface. In addition, when these metals are used, the heating of the treated body 4 in the surface treatment process is 100°C or higher and 700°C or lower. This is because the difference in thermal expansion coefficient at 100°C is sufficient as described above, so wrinkles and the like of the non-smooth surface sheet 2 can be removed even at 100°C, and if it is 700°C or higher, the shape of the metal will be affected. In other words, within this temperature range, the difference in thermal expansion coefficients can be fully utilized to press the non-smooth surface sheet 2.

1: Metal body with high thermal expansion coefficient, 2: Sheet with non-smooth surface, 3: Metal body with low thermal expansion coefficient, 4: Body to be treated

Claims (3)

A rolling step of rolling a material made of a metal material to form a sheet having a non-smooth surface having wrinkles or irregularities on the surface;
a clamping step of forming a treated body by sandwiching the textured surface sheet between a high thermal expansion metal body having a higher thermal expansion coefficient than the metal material forming the textured surface sheet and a low thermal expansion metal body having a lower thermal expansion coefficient than the metal material forming the textured surface sheet;
and a surface treatment step of heating the treated body to remove wrinkles or irregularities occurring on the surface of the non-smooth surface sheet ,
This method for manufacturing metal foil is characterized in that, in the clamping process, the high thermal expansion coefficient metal body is cylindrical or columnar in shape, the non-smooth surface sheet is wrapped around the high thermal expansion coefficient metal body, and the low thermal expansion coefficient metal body is further wrapped around the outside of the sheet . The method for manufacturing metal foil according to claim 1, characterized in that in the clamping process, the high thermal expansion metal body and the low thermal expansion metal body are in the shape of a flat plate having a thickness greater than that of the non-smooth surface sheet. The metal material is titanium nickel, the high thermal expansion metal body is stainless steel, and the low thermal expansion metal body is titanium;
2. The method for producing a metal foil according to claim 1, wherein the object is heated to a temperature of 100° C. or higher and 700° C. or lower in the surface treatment step.

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