JPS6134164A - Manufacture of alloy member for ornamentation - Google Patents

Abstract

PURPOSE:To manufacture an alloy member for ornamentation having high hardness and superior corrosion resistance and taking hardly scratches by heat treating a golden Cu-Al-Ni alloy under specified conditions. CONSTITUTION:A Cu-Al-Ni alloy consisting of 10-13% Al, 0.5-8% Ni and the balance Cu is cast into ornamental parts such as personal ornaments, tableware or artistic handicrafts. The resulting castings assume a gold color but have low hardness and inferior corrosion resistance. The castings are heated once to 750- 1,000 deg.C and water- or oil-quenched to precipitate a martensite phase in the structure. This precipitated martensite phase increases the hardness and improves the corrosion resistance, so fine alloy members for ornamentation having superior characteristics are obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a decorative alloy member, and more particularly to a method for manufacturing a decorative alloy member with excellent mechanical strength and corrosion resistance.

[Technical background of the invention and its problems]

Generally, copper alloys are used for decorative purposes such as arts and crafts in addition to industrial uses such as mechanical parts. Copper alloys have a characteristic coppery to golden color tone and are cheaper than precious metals such as gold and silver.
Demand is increasing in the field of pure art or applied art such as accessories, tableware, and arts and crafts.

Among such copper alloys, AJ10-13%, Ni2
A Cu-Afl-Ni alloy consisting of /6% and the remainder Cu is superior as a decorative alloy member for casting because of its relatively good corrosion resistance. However, the above copper alloy has a problem in that the β phase decomposes into the α phase and the γ2 phase during the casting process, resulting in deterioration of corrosion resistance and mechanical properties. Conventionally, as a method for reducing the β phase, for example, Fe3~
Further addition of 6% or more Ni is being carried out. It has also been attempted to contain Mn in an amount of 7 to 14% to approximate the decomposition rate of the β phase.

However, it is not necessarily preferable to contain a large amount of l"e, Ni, or Mn from the viewpoint of corrosion resistance, and addition of Ni is disadvantageous from the economic point of view. Furthermore, it is difficult to prevent the precipitation of the β phase. If it is suppressed, the hardness of the alloy material decreases, making it undesirable as a decorative material.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and provides a decorative copper alloy member with excellent both hardness and corrosion resistance! The purpose is to provide legal services.

[Summary of the invention]

In order to achieve the above object, the method for manufacturing a decorative alloy member of the present invention has a weight ratio of 8110 to 13% and a Ni content of 0.5 to 8%.
%, balance Cu and unavoidable impurities.
It is characterized in that it is heated to a temperature of 0 to 1000°C and then cooled with water or oil to form a martensitic structure.

The purpose of addition of each component in the alloy according to the present invention and the reason for limiting the composition are as follows. In the following description, "%" representing the composition is based on heavy equipment unless otherwise specified.

First, Ajl is an element necessary for imparting a beautiful golden tone and is contained in an amount of 10 to 13%.

If it is less than 10%, it becomes difficult for the martensite phase to precipitate, and the hardness becomes less than 2008V, making it easy to scratch as a non-decorative product. On the other hand, when added in excess of 13%, the golden color tone is lost and the strength becomes weak.

Furthermore, since the martensitic transformation point is below room temperature, sub-zero treatment is required as a subsequent heat treatment, which is not preferable.

Ni is an element effective in improving corrosion resistance, and 0.5 to 8%
included. If the content is less than 0.5%, problems such as clouding on the surface of the member due to long-term use and impaired planning will occur. On the other hand, even if it is added in an amount exceeding 8%, the effect of improving corrosion resistance is saturated and the cost increases, which is not preferable.

When adding the above components and Cu as the main component, the impurities incidentally included should be as small as possible (the smaller the better).

The method according to the present invention is characterized in that the alloy having the above composition range is heated to a specific depletion range and then cooled to change the alloy structure into a martensitic structure.

First, an alloy having the above composition is cast, heated to a temperature of 750 to 1000°C by the IC method 1], 1;3, and then cooled. It is preferable that cooling is performed by water cooling IJ1 or oil cooling H1. In this heat-treated culm, the martensitic 1-phase precipitates in the raw material, and as a result, the corrosion resistance is dramatically improved and the hardness is also increased.

(Examples and Comparative Examples of the Invention) Example 1 An alloy consisting of 10.5% 80, 4% Ni, and the balance CLI was melted in vacuum and poured into a mold (-in-F2 was created and : This was made into a master alloy and melted in an atmosphere of non!i'+bamboo gas to create lost wax.The ornament was cast into a mold.The ornament was heated at 950'C for 2 hours. 1) Oil-cooled 1.II L 7j. When the metallographic structure was observed, it was recognized that it had a martensitic structure. Also, the hardness was 300 (1" V). Then,
In order to evaluate corrosion resistance, an artificial sweat immersion corrosion test was conducted. Artificial sweat - Na CN 10H, lactic acid 11 Idl, urea 1.5g, Anz -7-1v n in 1Q of C1 water
1. ) When the product was soaked for 24 hours and the surface was observed, no discoloration was observed.

Example 2 An alloy consisting of A, 11.5% Ni, 3% Ni, and the balance Cu was melted in a vacuum to create an invoice 1- in a mold with V''/u. This was melted in an inert gas atmosphere as a master alloy. C1
Decorations were cast into molds made with zero-stack wax. This ornament was heated at 850° C. for 2 hours and then oil-cooled by IJI. Observation of the metallographic structure revealed a martensitic phase, and the hardness was 330 (11v).

In order to evaluate the corrosion resistance, an artificial sweat immersion corrosion test was conducted, but no discoloration was observed on the surface even after 24 hours of immersion.

An ingot was prepared by vacuum melting an alloy consisting of 1 挌J1 Δ, 012.5%, 5% Ni, and the balance Cu and cast into a mold. This was melted as a mother alloy in an inert gas atmosphere, and the ornament was cast into a mold made of lost wax. This ornament was heated at 750° C. for 2 hours and then cooled with water. When observing the metal IJ weave, it shows a martensite phase (the IZ size is 5).
00 (1-IV).

Evaluation of corrosion resistance - 4 IJ men - [sweat spray corrosion test (j
However, no tJ discoloration occurred after 24 hours.

An alloy consisting of 11.5% Ni, 3% Ni, and the balance CLI was vacuum melted and cast into a mold to produce an ingot. This was used as a mother alloy and melted in an inert gas atmosphere, and the ornaments were cast into a mold made of Ross wax. The metal structure in the as-cast state was a mixed structure of α phase, β phase, and γ2 phase. The hardness was 250 (l''v).

In order to evaluate corrosion resistance, an artificial sweat immersion corrosion test was conducted.
When observed after 24 hours, some discoloration was observed on the surface of the ornament.

(Effect of the invention) As is clear from the results of the above examples and comparative examples,
The member obtained by the method of the present invention has a beautiful color tone based on a specific phase.After casting, the member has a specific dryness condition. 1, the material structure is changed by heat treatment.
Because it has a structure, it has excellent properties of both hardness and corrosion resistance. Therefore, the method of the present invention is useful as a method for producing decorative alloy members that require a balance of these properties.

Claims (1)

[Claims] Weight ratio: Al 10-13%, Ni 0.5-8%, balance C
750 to 100 of an alloy consisting of u and unavoidable impurities
It is characterized by heating to a temperature of 0°C and then cooling with water or oil to form a martensitic structure.
A method for producing decorative alloy parts with excellent hardness and corrosion resistance.