JPH02217483A - Copper sheet for ornament - Google Patents

Abstract

PURPOSE:To produce a Cu sheet for ornament in which the characteristics of Cu as metal are made the most of by subjecting a cold worked stock of a unidirectionally solidified ingot of Cu or Cu alloy to etching treatment and allowing an attractive straight-grain pattern of unidirectionally solidified structure to appear. CONSTITUTION:A melt 3 of pure copper, such as oxygen-free copper, or Cu alloy, such as Cu-Zn, Cu-Sn, and Cu-Al, is held in a casting furnace 4, drawn out through a horizontal mold 6 heated by means of a heating device 5, and cooled by means of a cooler 8, and the resulting cast ingot 7 is drawn out by means of pinch rolls 9. At this time, the solid-liquid interface 10 of the above cast ingot 7 is formed perpendicular to the drawing-out direction of the cast ingot 7, and a unidirectionally solidified structure in which crystalline grains extend into columnar state in the longitudinal direction of the cast ingot 7 is provided. A substrate is cut off from the cold rolled sheet of the above continuously cast ingot, and, after the cut side face is ground, the substrate is immersed into an aqueous solution of mineral acid, such as HNO3, HCl, and H2SO4, and etched to allow the unidirectionally solidified structure 2 to appear, and finally, clear lacquer is also applied to the above, by which the Cu or Cu alloy stock for ornament in which the attractive gold-colored straight-grain pattern of unidirectionally splidified structure is allowed to appear can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a decorative copper plate in which unidirectionally solidified fibers are exposed.

[Conventional technology and its issues]

Copper or copper alloys are shiny, colored metals with excellent corrosion resistance, so they have been used in decorative items such as wall hangings and pendants since ancient times.

However, conventional copper ornaments are used by drawing pictures or engraving patterns on copper plates with polished surfaces, which do not fully take advantage of the characteristics of copper as a metal, and do not allow the user to use it. was also limited to some people.

[Means to solve the problem]

The present invention was made in view of this situation, and its purpose is to provide a beautiful decorative copper plate that takes advantage of the characteristics of copper as a metal.

That is, the present invention is characterized in that a unidirectionally solidified copper or copper alloy ingot or a cold-worked material of the ingot is etched to reveal a unidirectionally solidified structure.

An ingot made by melting copper or copper alloy and solidifying it in one direction is
As shown schematically in Fig. 1, the crystal structure consists of long columnar crystals 1 that grow long in the direction of solidification, and the present invention etches the surface parallel to the direction of solidification of the ingot. This was done by focusing on the fact that the unidirectionally solidified structure 2 as shown in FIG.

In the unidirectionally solidified structure 2, the width of the columnar crystals 1 can be changed arbitrarily depending on the casting conditions, and the casting speed can be increased as shown in FIG. 3, which shows the relationship between the casting speed and the crystal grain size. The spacing between the columnar crystals becomes narrower.

In addition to the unidirectionally solidified ingots, the copper plate of the present invention can also be applied to processed materials obtained by cold-working the above-mentioned ingots. The crystals are thin (elongated) and exhibit a straight-grained birch shape that is more clear than that of the ingot.

In producing the copper plate of the present invention, methods for unidirectionally solidifying copper or copper alloy include a heated mold continuous casting method in which heat extraction is performed only through the produced ingot, Ge single crystal production, etc. Any casting method can be used as long as it can solidify in one direction, such as the ingot rotation pull-up casting method used in

The copper or copper alloy used to form the copper plate of the present invention may include pure copper such as tough pitch copper or oxygen-free copper, as well as Cu-Zn series, Cu-5n series, C
Copper alloys such as u-Al type can be arbitrarily selected according to preferences such as color.

In manufacturing the copper plate of the present invention, a method of etching a unidirectionally solidified ingot or a cold-worked material obtained by subjecting the ingot to a unidirectionally solidified ingot, includes etching the ingot or cold-worked material in nitric acid, hydrochloric acid, sulfuric acid, etc. A method such as immersion in an aqueous solution is mainly used.

The shape of the copper plate of the present invention is not limited to a plate shape,
Any shape such as a round bar can be applied.

The copper plate of the present invention may be used for drawing pictures with the unidirectionally solidified structure left behind, thereby making it a more tasteful decorative item.

[Effect]

One-way solidified ingots made by heat extraction and solidification of molten metal from only one end, or processed materials obtained by cold working this ingot, have a crystal structure in which a plurality of columnar crystals extend parallel to the longitudinal direction. When a surface parallel to the longitudinal direction of a lump or processed material is polished and etched, the degree of corrosion due to etching differs for each columnar crystal, and as a result, each columnar crystal has a difference in color or brightness, and the entire etched surface looks like wood. It looks like a straight grain pattern. In addition, the differences in color or brightness of each columnar crystal caused by etching are difficult to disappear,
The straight grain pattern remains clear for a long time.

〔Example] The present invention will be explained in detail below using examples.

Example 1 Oxygen-free 1II (OFC) with a purity of 99.99% was melted in a melting furnace, and the molten metal was cast into a mold with a cross-sectional size of 10 x 900 m using a heated mold continuous casting device shown in Fig. 4. It was cast into a plate-shaped ingot.

That is, the molten metal 3 is transferred to a heater-embedded casting furnace 4 and held at 1150°C, and passed through a mold 6 whose inner surface is heated to 1090°C with a heater 5. The ingot 7 produced from the ingot was continuously cast by being cooled by running water in a cooler 8 and pulled out by pinch rolls 9 at a speed of 100 min/sin. In the above, since the melting point of copper is 1083°C, heat extraction during solidification is performed exclusively through the ingot 7, and as a result, the solid-liquid interface 10 is formed almost perpendicular to the drawing direction of the ingot 7, and the resulting ingot is The ingot 7 had a unidirectionally solidified structure in which crystal grains extended in the longitudinal direction of the ingot 7.

In addition, since the amount of water flowing from the cooler 8 is controlled so that the solid-liquid interface 10 is located near the mold outlet, the ingot rubs against the mold and segregates on the surface of the ingot, as in normal water-cooled casting. The surface quality was extremely excellent, with no defects such as hot spots, like knees, cracks, blisters, or thick oxide films.

The obtained ingot was cut into a substrate with a size of 10 cm x 16 cm, and the cut side surface was polished, and then this substrate was immersed in a 10% nitric acid aqueous solution and etched to reveal a unidirectionally solidified structure. Then, a clear lacquer was applied to protect the entire surface of the board, creating a copper plate for painting.

This copper plate had a straight-grained pattern consisting of a relatively coarse unidirectionally solidified structure with a grain spacing of about 1Offi11, and was reddish and beautiful, and was viewed by leaning it on a pedestal and placing it on a table.

Example 2 The plate-shaped ingot produced in Example 1 was cold rolled to form a wall plate. The above cold rolling was carried out without using a solidifying agent since there were no defects on the ingot surface.

Furthermore, since the cold rolling was carried out in the direction of solidification, that is, in the direction parallel to the grain boundaries, the work hardening rate was low, and the material could be rolled to a thickness of 50 μm without intermediate annealing.

Of the rolled material thus obtained, 0.3 m and 5 m
A rolled material with a thickness of 0.0 mm was cut into a substrate with a size of 1010 x 20 mm, and this substrate was immersed in a 10% nitric acid aqueous solution and etched to reveal a unidirectionally solidified structure.
A clear lacquer was applied to the etched surface to protect it, creating a decorative copper plate.

Next, the above-mentioned copper plate with a thickness of 0.3 m was left as it was, and
The 0μ copper plates were lined with plywood, and a hanging device was attached to each plate to serve as a wall hanging plate.

The obtained plates were all beautiful, reddish and straight-grained, consisting of a coarse unidirectionally solidified structure with a crystal grain interval of about 13 m.

Example 3 A wall plate was produced in the same manner as in Example 2, except that a Cu-30% Zn alloy was used as the cast metal, the mold inner surface temperature was 1060° C., and the casting speed was 150 tIm/min.

The obtained plates were all beautiful, golden yellow and had a straight grain pattern consisting of a fine unidirectionally solidified structure with a grain spacing of 3-.

〔effect〕

As described above, the decorative copper plate of the present invention makes use of the characteristics of copper as a metal by expressing the beautiful straight grain of the unidirectionally solidified structure. It is still in use.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the crystal structure of a unidirectionally solidified ingot;
The figure is a replica of a unidirectional solidification structure, FIG. 3 is a diagram showing the relationship between casting speed and grain size, and FIG. 4 is an explanatory diagram of a heating mold casting device showing an example of a unidirectional solidification casting device. . 1... Columnar crystal, 2... Unidirectional solidification IJ1m, 3
... Molten metal, 6... Mold, 7... Ingot. Patent applicant Furukawa Electric Co., Ltd. Solidification direction columnar crystals Figure 1 Casting speed (s/min) Figure 3 Figure 2

Claims (1)

[Claims] 1. A decorative copper plate, characterized in that a unidirectionally solidified copper or copper alloy ingot or a cold-worked material of the ingot is etched to reveal a unidirectionally solidified structure.