WO2015046421A1

WO2015046421A1 - Discoloration-resistant copper alloy and copper alloy member

Info

Publication number: WO2015046421A1
Application number: PCT/JP2014/075612
Authority: WO
Inventors: 真次田中; 恵一郎大石; 畑　克彦
Original assignee: 三菱伸銅株式会社
Priority date: 2013-09-26
Filing date: 2014-09-26
Publication date: 2015-04-02
Also published as: TWI516615B; JP5933848B2; TW201516165A; JPWO2015046421A1

Abstract

　Provided is a metal structure containing 17-34 mass% Zn, 0.01-2.5 mass% Sn, 0.005-1.8 mass% Al, and 0.0005-0.030 mass% Pb, the balance being Cu and unavoidable impurities, the above elements being contained in amounts such that the relationships 24 ≤ [Zn] + 5 × [Sn] + 3 × [Al] ≤ 40 and 1.2 ≤ [Sn] + 2 × [Al] ≤ 4.0 are satisfied, the area ratio (γ)% of the γ phase and the area ratio (β)% of the β phase in the α-phase matrix having the relationship 0 ≤ 2 × (γ) + (β) ≤ 1.5, and 0-0.7% of the γ phase and 0-0.9% of the β phase, in terms of area ratio, being dispersed in the α-phase matrix.

Description

Discoloration-resistant copper alloy and copper alloy member

The present invention relates to a discoloration-resistant copper alloy having a brass color and having discoloration resistance, and a copper alloy member using the discoloration-resistant copper alloy, and in particular, hot workability, cold workability, press The present invention relates to a discoloration-resistant copper alloy excellent in workability such as property and mechanical properties, and excellent in antibacterial and bactericidal properties, and a copper alloy member using this discoloration-resistant copper alloy.
This application claims priority based on Japanese Patent Application No. 2013-199475 filed in Japan on September 26, 2013, the contents of which are incorporated herein by reference.

Conventionally, copper alloys such as Cu—Zn have been used in various applications such as piping equipment, building materials, electrical / electronic equipment, daily necessities, and machine parts. Among the building materials, in applications such as handrails, decorations such as door knobs, metal fittings for construction, Western tableware, keys, etc., it is required to be difficult to discolor due to aesthetic problems. In order to meet such demands, copper alloy products are coated with a resin such as nickel / chrome plating or clear coating.
However, the plated product peels off from the plated product after long-term use. Further, the coated product has a problem that the color tone changes with the passage of time and the coating film peels off. Moreover, since the plated product and the coated product do not come into contact with the copper alloy, the antibacterial property (bactericidal property) of the copper alloy is impaired.

A copper alloy such as Cu—Zn has a brass color when the Zn content exceeds 15 mass% or 20 mass%. However, when a protective film such as plating or painting is not formed and used as a decoration on the surface of the material, the color changes to brown or reddish brown in a short period of time, although it is affected by the environment in which it is placed. In addition, the discoloration situation does not change uniformly, and the discoloration or the color tone varies depending on the environment, part or location, and the original beautiful metallic gloss cannot be maintained.

Conventionally, Cu—Ni—Zn alloys exhibiting a glossy white color similar to plating and aluminum bronze exhibiting a golden color have been proposed as copper discoloration resistant materials.
As such a Cu—Ni—Zn alloy, for example, JIS C 7941 includes Cu (60.0 to 64.0 mass%), Ni (16.5 to 19.5 mass%), Pb (0.8 to 1). .8 mass%), free-cutting white containing Zn (remainder) and the like. Patent Document 1 discloses Al (5 to 9 mass%), Ni (1 to 4 mass%), In (0.005 to 0.3 mass%), Mn (0.1 to 0.5 mass%), Co ( 0.001 to 0.01 mass%), Be (0.0025 to 0.2 mass%), Ti (0.001 to 0.01 mass%), Cr (0.05 to 0.2 mass%), Si (0. Aluminum containing one or two of 001 to 0.5 mass%), Zn (0.005 to 0.5 mass%), Sn (0.003 to 0.4 mass%), the balance being Cu and inevitable impurities A copper alloy is disclosed.

Moreover, it is known that a copper alloy has an antibacterial action (bactericidal action). In medical institutions such as hospitals, there is a problem commonly referred to as nosocomial infection in which patients with Staphylococcus aureus, Pseudomonas aeruginosa, etc. that have acquired drug resistance such as antibiotics are infected. In addition, diseases caused by bacteria or viruses are regarded as problems, such as the spread of influenza and other infectious diseases.
For example, in nosocomial infections, there are various routes of causative bacteria, and the patient who has the bacteria touches it, and another patient or medical worker touches the place where the bacteria are attached, and the causative bacteria spread in the hospital. It is possible. By using a copper alloy as an object touched by these patients and medical staff, these bacteria are killed or reduced. And it is expected to reduce nosocomial infections due to the interruption of the infection route. Specifically, the handle, lever handle, door handle, etc. installed on each door in the hospital, or the fence, side rail, and nur skirt installed on the bed are made of copper alloy, thereby expanding the path of bacteria. You can expect less. In addition, for influenza, etc., infection by various bacteria and viruses can be achieved by using antibacterial (bactericidal) copper alloys for members that can be contacted by an unspecified number of people in public institutions such as trains, buses or parks. It becomes possible to prevent.

Japanese Unexamined Patent Publication No. 2004-143574

However, since the copper alloy disclosed in JIS C 7941 contains a large amount of Ni and Pb and has problems in health and hygiene, its use is limited. Ni causes a particularly strong Ni allergy among metal allergies. Moreover, since Pb is a harmful substance as is well known, there is a problem in its use as a construction fitting such as a handrail that directly touches human skin, or a personal item such as a home appliance. Further, when Ni is contained in a large amount, the workability such as hot rolling property and pressability is inferior, and the manufacturing cost is increased due to the high cost of Ni, so that the use is limited.
Furthermore, the copper alloy disclosed in Patent Document 1 is an aluminum-containing alloy containing 5 mass% or more of Al, which is excellent in discoloration resistance, but is inferior in workability such as rolling. It is difficult to process into a thin plate. Furthermore, cold workability is poor, such as bending at 90 ° bending, for example, because the ductility is poor and cracking occurs in the bent portion. In addition, the formation of an aluminum oxide film on the surface makes the antibacterial property weak, and the antibacterial property is lost after long-term use.

Also, when normal copper alloy is actually used for the handle, lever handle, door handle, etc., there will be a difference in color tone between the part that touches the human body and the part that does not. In long-term use, the part with much contact with the human body is removed by physical action such as wear due to contact with the human body even if the discoloration layer (oxide) is formed slowly or even if the discoloration layer is formed. Therefore, the difference in color tone from other parts (parts with little contact with the human body) becomes clearer, and it is hard to say that the appearance is very good. The difference in color tone is due to the fact that the human body touches the material and the sweat, sebum, etc. of the human body adheres to the material, and the effect of promoting or delaying the discoloration by the adhered substance causes the place where the human body does not touch and the surface conditions. Caused by different things. In addition, discoloration varies depending on the environment in which the material is used. It is more likely to occur at higher temperatures and humidity, and it appears more prominently in places where water droplets (including rainwater, etc.) are attached. Discoloration occurs. For this reason, most of the copper alloy handles used in these applications are used in a state in which the surface of the copper alloy is covered with plating, clear coating, or the like and discoloration hardly occurs.

Copper alloy is a colored metal not found in other metals, and typical colors include reddish-orange of copper, yellow of brass (Cu—Zn alloy) or silver white of western (Cu—Ni—Zn alloy). . As described above, the copper alloy becomes a material of various colors depending on the additive element. However, when used under the condition of contacting with the human body as described above, it is difficult to avoid discoloration although it varies depending on the alloy. In particular, red-orange copper and yellow brass change color in a very short time, but they have a color tone not found in other metals, so these colored copper alloy materials from the viewpoint of design, design or aesthetics May be used. However, in order to prevent discoloration, a resin film such as a clear coat is coated (painted) on the surface, and the above-described antibacterial (bactericidal) function is not exhibited.

The present invention has been made against the background as described above, and has a yellow (brass) color tone and is excellent in workability such as hot workability, cold workability, pressability, and the like. The object is to provide a discoloration-resistant copper alloy excellent in both discoloration resistance and antibacterial properties (bactericidal properties) and a copper alloy member using this discoloration-resistant copper alloy.

In order to solve the above problems, the present inventors have studied the composition and metal structure of a copper alloy exhibiting a brass color, and as a result, have obtained the following knowledge.
In the Cu—Zn—Sn—Al alloy, depending on the content of each additive element, when the material becomes hot, such as hot rolling or hot extrusion, a β phase appears in the matrix. Deformation resistance is lowered, and hot deformability is improved. However, if the β phase area ratio is 0.9% or the γ phase area ratio exceeds 0.7% at room temperature (room temperature), the ductility deteriorates, and cold rolling or cold drawing in the next process, etc. In addition to the cold workability, discoloration resistance and the like deteriorate. Further, the pipe material is inferior in processing such as bending and flattening with a small radius of curvature. Furthermore, the corrosion resistance is adversely affected, and the dezincification corrosion resistance and stress corrosion cracking resistance are deteriorated. Note that the β phase appearing in the Cu—Zn—Sn—Al alloy contains Sn and Al, and thus is harder and more brittle than the β phase of the Cu—Zn alloy.

In addition, in a Cu—Zn—Sn—Al alloy, a β phase appears when processed at a high temperature such as hot rolling or hot extrusion, and a γ phase appears from a β phase due to a eutectoid reaction depending on cooling conditions. . The γ phase is harder than the α phase, which occupies most of the matrix, has a higher Zn content than the β phase, and contains Sn and Al more than twice as much as the β phase. It is a brittle phase. When the area ratio of the γ phase exceeds 0.7%, the ductility of the material becomes poor as in the β phase, and the cold workability decreases. Moreover, although the influence is smaller than that of the β phase, the corrosion resistance such as dezincification corrosion resistance is lowered, and the discoloration resistance is also deteriorated. Further, if the γ phase exceeds 0.7%, the ductility of the material is remarkably lowered, and if it is used for a member to which an impact is applied, the possibility of cracking is increased. The same applies to a Cu—Zn—Sn—Al—Ni alloy in which a part of Sn and Al is replaced by Ni, and the metal structure in the matrix affects various properties of the material.

The Cu—Zn alloy is generally processed by hot rolling or hot extrusion after heating an ingot produced by casting to a high temperature. Thereafter, a product having a desired size is obtained by repeating heat treatment such as cold rolling or drawing plastic working and annealing. For materials with poor hot workability, such as Cu—Sn alloy and Cu—Zn—Ni alloy, casts that are thinner (rolled product) or thinner (extruded material) than the ingot are produced by continuous casting, and then cooled. Manufactured by hot working. The ingot can be manufactured at about 10 tons per hour although it depends on the mold. However, the continuous casting has a smaller cross-sectional area than the ingot, so the production amount per hour is as small as a few. Become. For this reason, the production cost is lower in the ingot production than in the continuous casting, and many copper alloys employ a method of producing by hot working after producing the ingot. A Cu-Zn-Sn-Al alloy can be produced by hot rolling or hot extrusion as well as a Cu-Zn alloy, but it can also be produced by continuous casting. Manufacturing by casting may be cost effective.

As described above, although affected by the amount of each element added and the manufacturing conditions, the β phase that appears when the material becomes high temperature is transformed into a γ phase in the cooling process, and the β phase remains at room temperature, Each phase alone exceeds the area ratio of 0.7% (γ phase) and 0.9% (β phase), respectively, and the area ratio of β phase and γ phase is (β)% and (γ), respectively. %, If 2 × (γ) + (β) exceeds 1.5% in total, cold workability may deteriorate due to a decrease in cold ductility, and discoloration resistance and corrosion resistance may deteriorate. There is.

In addition, the antibacterial properties (bactericidal properties) of solid copper alloys are exhibited by the generation of active oxygen groups such as hydrogen peroxide and active radicals on the surface, and these active oxygen groups act on bacterial cell membranes and DNA. Is done. On the surface of the copper alloy produced by this active oxygen group, copper contributes to the oxidation / reduction reaction and reacts with moisture and the like present in the atmosphere. In addition, when the liquid contacts the copper alloy, the antibacterial (bactericidal) liquid that comes into contact with the copper alloy reacts to elute copper ions. These reactions are the same as the so-called corrosion of a copper alloy, and when antibacterial properties (bactericidal properties) are exerted, a corrosion reaction occurs on the surface of the copper alloy. The corrosion of the surface of the copper alloy is a cause of discoloration of the copper alloy. Thus, antibacterial properties (bactericidal properties) are properties that are basically opposite to discoloration resistance, and increasing the discoloration resistance leads to weakening the antibacterial properties (bactericidal properties). That is, discoloration resistance and antibacterial properties (bactericidal properties) are not always compatible. In order to achieve such conflicting characteristics, a relational expression such as Zn, Sn, and Al and a relational expression such as Sn and Al are important.

The present invention has been completed based on the above-mentioned findings of the present inventors. That is, the following invention is provided in order to solve the said subject.
The color-change-resistant copper alloy according to the first aspect of the present invention comprises 17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, 0.005%, and 0.1%. 0005 to 0.030 mass% of Pb, with the balance being Cu and inevitable impurities, Zn content [Zn] mass%, Sn content [Sn] mass%, and Al content [Al ] Mass%, and the relation of 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] ≦ 40, and the Sn content [Sn] mass% and the Al content [Al ] Mass%, 1.2 ≦ [Sn] + 2 × [Al] ≦ 4.0, and the area ratio (γ)% of the γ phase of the α phase matrix and the area of the β phase The ratio (β)% has a relationship of 0 ≦ 2 × (γ) + (β) ≦ 1.5, and the α phase matrix The metal structure is such that 0 to 0.7% γ phase and 0 to 0.9% β phase are dispersed in the coke.

According to the discoloration-resistant copper alloy that is the first aspect of the present invention, the contents of Zn, Sn, Al, and Pb are within the above-mentioned range, and the relationship between Zn, Sn, and Al, Sn and Al Are defined within the above-mentioned ranges, respectively, so that a brass color is exhibited. Furthermore, it is possible to achieve both discoloration resistance and antibacterial properties (bactericidal properties), and it is possible to improve the discoloration resistance while maintaining the excellent antibacterial properties (bactericidal properties) of the copper alloy.
Moreover, since the area ratios of the γ phase and the β phase in the α phase matrix are defined as described above, workability, discoloration resistance, and corrosion resistance can be improved.

The discoloration-resistant copper alloy according to the second aspect of the present invention comprises 17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, 0.005% by weight, 0.1% to 0.2% by mass, 0.1% to 0.1% by mass, It contains Pb of 0005 to 0.030 mass%, Ni of 0.01 to 5 mass%, the balance is made of Cu and inevitable impurities, Zn content [Zn] mass%, and Sn content [Sn] mass %, Al content [Al] mass%, and Ni content [Ni] mass%, 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] −0.5 × [Ni] ≦ 40 and 1.2 ≦ between the Sn content [Sn] mass%, the Al content [Al] mass%, and the Ni content [Ni] mass% 0.7 × [Ni] + [Sn] + 2 × [Al] ≦ 4.0 In addition, there is a relationship of 0 ≦ 2 × (γ) + (β) ≦ 1.5 between the area ratio (γ)% of the γ phase and the area ratio (β)% of the β phase of the α phase matrix, It is a metal structure in which 0 to 0.7% γ phase and 0 to 0.9% β phase are dispersed in an α phase matrix.

In the discoloration-resistant copper alloy that is the second aspect of the present invention, a part of Sn and Al in the discoloration-resistant copper alloy that is the first aspect described above was replaced with Ni. Here, the contents of Zn, Sn, Al, Pb, and Ni are within the above ranges, and the relationship between Zn, Sn, Al, and Ni, and the relationship between Sn, Al, and Ni are within the above ranges, respectively. Therefore, it is possible to improve the discoloration resistance while maintaining the excellent antibacterial property (bactericidal property) of the copper alloy. Further, by adding Ni, it is possible to further improve discoloration resistance and corrosion resistance.
Furthermore, since the area ratios of the γ phase and the β phase in the α phase matrix are defined as described above, workability, discoloration resistance, and corrosion resistance can be improved.

Further, the color-change resistant copper alloy according to the third aspect of the present invention is the color-change-resistant copper alloy according to the first and second aspects described above, and further 0.01 to 1.0 mass% of Si, 0.01 Contains at least one of -0.5 mass% Ti, 0.01-1.5 mass% Mn, 0.001-0.09 mass% Fe, and 0.0005-0.03 mass% Zr. , Zn content [Zn] mass%, Sn content [Sn] mass%, Al content [Al] mass%, and each content of Si, Ti, Ni, Mn, Fe and Zr Between [Si] mass%, [Ti] mass%, [Ni] mass%, [Mn] mass%, [Fe] mass% and [Zr] mass%, 24 ≦ [Zn] + 5 × [Sn ] + 3 × [Al] + 2.5 × [Si] Having 1.0 × [Ti] -0.5 × [Ni] + 0.5 × [Mn] + 0.2 × [Fe] + 0.1 × [Zr] ≦ 40 relationship.

According to the discoloration-resistant copper alloy that is the third aspect of the present invention, desired elements can be obtained by appropriately adding elements such as Si, Ti, Mn, Fe, and Zr within the above range according to the intended use. It becomes possible to obtain a discoloration-resistant copper alloy having And even when these elements are added, the excellent antibacterial properties of the copper alloy can be obtained by keeping the relationship among Zn, Sn, Al, Ni, Si, Ti, Mn, Fe, and Zr within the above range. It becomes possible to improve discoloration resistance while maintaining (bactericidal properties).

The discoloration-resistant copper alloy according to the fourth aspect of the present invention is the discoloration-resistant copper alloy according to the first to third aspects described above, and further 0.005 to 0.09 mass% P, 0.01 to One or more of 0.09 mass% Sb, 0.01 to 0.09 mass% As, and 0.001 to 0.03 mass% Mg are contained.

According to the discoloration-resistant copper alloy that is the fourth aspect of the present invention, elements such as P, Sb, As, and Mg are appropriately added within the above-mentioned range according to the intended use, thereby providing desired characteristics. It is possible to obtain a discoloration-resistant copper alloy. The content of these elements is regulated to be relatively small and has little effect on antibacterial properties (bactericidal properties) and discoloration resistance, so it is necessary to consider the relationship with Zn, Sn, Al, etc. Absent.

The discoloration-resistant copper alloy according to the fifth aspect of the present invention is characterized in that it is used in the form of a welded tube, a forged product or a casting in the discoloration-resistant copper alloy according to the first to fourth aspects described above. .
According to the discoloration-resistant copper alloy which is the fifth aspect of the present invention, it can be widely applied as a member of various products by using it in the form of a welded tube, a forged product or a casting.

The discoloration-resistant copper alloy according to the sixth aspect of the present invention is the discoloration-resistant copper alloy according to any of the first to fifth aspects described above, wherein the viable cell ratio after 10 minutes in the antibacterial test is It is equal to or lower than the rate.
According to the discoloration-resistant copper alloy of the sixth aspect of the present invention, it has antibacterial properties equivalent to or better than pure copper, and is a medical facility, public facility, research facility that is strict in hygiene management (for example, food, cosmetics) It can be applied as a member of products used in pharmaceuticals, etc.).

The copper alloy member of the present invention is formed by joining a base material made of a color-change resistant copper alloy made of the color-change resistant copper alloy of the first to fifth aspects and another member. Examples of other members include discoloration-resistant copper alloys of the present invention, general copper and copper alloys, steel materials, stainless steel, aluminum alloys and other metal materials, resins, wood, and other products using discoloration-resistant copper alloys. The material of various members is shown according to the purpose.
According to the copper alloy member of this configuration, since the above-mentioned discoloration-resistant copper alloy is used as a base material, discoloration of the base material is suppressed and antibacterial properties (bactericidal properties) are excellent, and various uses Can be used.
Specific uses of the copper alloy member of the present invention include door handles, door knobs, door push plates, handrails, bed rails, sideboards, desk tops, chair backrests, skirt handle members, pen grips, and keyboards. , Mice, sinks, straps and building materials.

According to the present invention, it has a yellow (brass color) color tone, is excellent in workability such as hot workability, cold workability, pressability, and is excellent in both discoloration resistance and antibacterial properties (bactericidal properties). It is possible to provide a discoloration-resistant copper alloy and a copper alloy member using the discoloration-resistant copper alloy.

Below, the discoloration-resistant copper alloy which concerns on embodiment of this invention is demonstrated. In the present specification, an element symbol in parentheses such as [Zn] indicates the content (mass%) of the element.
Moreover, in this embodiment, using this content display method, a plurality of composition indexes are defined as follows. In addition, in the composition index f1, with respect to elements not added and Sn, Al, Si, Ti, Ni, Mn, Fe, and Zr, when each content is less than 0.01 mass%, the composition index f1 It is assumed that [] = 0.

Composition index f1 = [Zn] + 5 × [Sn] + 3 × [Al] + 2.5 × [Si] + 1.0 × [Ti] −0.5 × [Ni] + 0.5 × [Mn] + 0.2 × [Fe] + 0.1 × [Zr]
Composition index f2 = [Sn] + 2 × [Al]
Composition index f3 = 0.7 × [Ni] + [Sn] + 2 × [Al]
Composition index f4 = [Sn] × [Al] + 0.1 × [Ni]

The discoloration-resistant copper alloy according to the first embodiment of the present invention includes 17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, 0 .0005 to 0.030 mass% of Pb, with the balance being Cu and inevitable impurities, Zn content [Zn] mass%, Sn content [Sn] mass%, and Al content [ [Al] mass% and the relation of 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] ≦ 40, and the Sn content [Sn] mass% and the Al content [ And Al] mass% have a relationship of 1.2 ≦ [Sn] + 2 × [Al] ≦ 4.0. That is, in the discoloration-resistant copper alloy according to the first embodiment, the composition index f1 is in the range of 24 ≦ f1 ≦ 40, and the composition index f2 is in the range of 1.2 ≦ f2 ≦ 4.0. Yes.
The discoloration-resistant copper alloy according to the first embodiment having the above composition is referred to as a first invention alloy.

The discoloration-resistant copper alloy according to the second embodiment of the present invention includes 17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, 0 .0005 to 0.030 mass% of Pb, 0.01 to 5 mass% of Ni, the balance being made of Cu and inevitable impurities, Zn content [Zn] mass%, Sn content [Sn] Between mass%, Al content [Al] mass%, and Ni content [Ni] mass%, 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] −0.5 × [Ni ≦ 40, and between the Sn content [Sn] mass%, the Al content [Al] mass%, and the Ni content [Ni] mass%, 1.2 ≦ 0.7 × [Ni] + [Sn] + 2 × [Al] ≦ 4.0 ing. Furthermore, in this embodiment, there is a relationship of 0.3 ≦ [Sn] × [Al] + 0.1 × [Ni] ≦ 1.4. That is, in the discoloration-resistant copper alloy according to the second embodiment, the composition index f1, 24 ≦ f1 ≦ 40 and the composition index f3 are in the range 1.2 ≦ f3 ≦ 4.0. Yes.
The discoloration-resistant copper alloy according to the second embodiment having the above composition is referred to as a second invention alloy.

The discoloration-resistant copper alloy according to the third embodiment of the present invention is the same as the above-described first and second invention alloys, further 0.01 to 1.0 mass% Si, 0.01 to 0.5 mass% Ti, Zn content [Zn] containing one or more of 0.01 to 1.5 mass% Mn, 0.001 to 0.09 mass% Fe, 0.0005 to 0.03 mass% Zr mass%, Sn content [Sn] mass%, Al content [Al] mass%, and Si, Ti, Ni, Mn, Fe and Zr content respectively [Si] mass%, Between Ti] mass%, [Ni] mass%, [Mn] mass%, [Fe] mass% and [Zr] mass%, 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] +2. 5 x [Si] + 1.0 x [Ti] -0 5 × [Ni] + 0.5 × [Mn] + 0.2 × [Fe] + 0.1 × have a relationship of [Zr] ≦ 40. That is, in the discoloration-resistant copper alloy according to the third embodiment, the composition index f1 is in the range of 24 ≦ f1 ≦ 40. The composition indexes f2 and f3 are within the ranges defined in the first embodiment or the second embodiment, respectively.
The discoloration-resistant copper alloy according to the third embodiment having the above composition is referred to as a third invention alloy.

The discoloration-resistant copper alloy according to the fourth embodiment of the present invention is the above-described first to third invention alloys, further comprising 0.005 to 0.09 mass% P and 0.01 to 0.09 mass% Sb. , 0.01 to 0.09 mass% As, and 0.001 to 0.03 mass% Mg. Here, P, Sb, and As are not considered in the composition index f1 because the content is small and the influence on the characteristics is small. Therefore, also in the discoloration-resistant copper alloy according to the fourth embodiment, the composition index f1 is in the range of 24 ≦ f1 ≦ 40. The composition indexes f2 and f3 are within the ranges defined in the first embodiment or the second embodiment, respectively.
The discoloration-resistant copper alloy according to the fourth embodiment having the above composition is referred to as a fourth invention alloy.

In the discoloration-resistant copper alloys (first to fourth invention alloys) according to the first to fourth embodiments of the present invention described above, the area ratio (γ)% of the γ phase of the α phase matrix and the area of the β phase. 0 ≦ 2 × (γ) + (β) ≦ 1.5 with the ratio (β)%, and the α phase matrix has an area ratio of 0 to 0.7% γ phase and 0 to 0 It has a metal structure in which 9% of the β phase is dispersed.

Hereinafter, the reason why the component composition, composition index f1, f2, f3, f4, and metal structure are defined as described above will be described.

(Zn: 17 mass% or more and 34 mass% or less)
Zn is a main element in the alloy of the present invention, and improves the mechanical strength such as tensile strength and proof stress, discoloration resistance and workability, and further improves the various characteristics by synergistic effects with Sn and Al. Have. Moreover, it is an important element in strengthening the antibacterial (bactericidal) effect and ensuring the properties of the copper alloy. Note that a copper alloy containing a large amount of Zn is more excellent in discoloration resistance and strength than pure copper or a copper alloy having a high copper concentration, and is equivalent or superior in antibacterial properties (bactericidal properties). Furthermore, it is an essential element for exhibiting yellow (yellowish color tone, brass color), which is a characteristic color tone of brass which is an alloy with Cu. Depending on the content of Zn, Sn, Al, etc. (Cu is the balance), the β phase will appear, and the possibility that the β phase will remain even at room temperature (room temperature) increases, and it depends on the area ratio of the β phase. This may cause problems such as poor workability and corrosion resistance. Further, although depending on the contained components, the γ phase is produced by a eutectoid reaction depending on the cooling conditions from the β phase, and when the γ phase is present in the matrix, the cold workability and corrosion resistance are deteriorated as in the β phase. The same applies to a portion to be joined such as brazing or welding that is heated at a high temperature. In addition, the welded pipe is a strip product (product wound with a tape-shaped coil), formed into a circle using a roll (mold), and welded at both ends to obtain a pipe material. When heated, the temperature rises and the melting point is locally exceeded. In addition, since the material thickness (thickness in the pipe material) is thin, the cooling rate when air-cooled after welding is fast, and the welded part and its vicinity (width 10mm (one side 5mm) apart from the welded part) In the heat-affected zone, the β phase tends to remain. In addition, there are various welding pipe welding methods such as heating using a high-frequency induction heating coil, welding together, and joining the welded part directly by TIG welding. However, the welding method is not limited to these, and any welding / joining method can be used as long as both ends of the material after roll forming can be welded online. Similarly in brazing, there is a method of brazing in the furnace using a conveyor furnace, but there is also a method of hand brazing where the brazed portion is partially burned by a human hand, and in either case The brazing portion is heated to a temperature higher than the melting point of the brazing material or higher, for example, a temperature of 800 degrees or higher. In the case of hand brazing, the heated part is rapidly cooled as in welding, and the β phase tends to remain.

Further, the copper alloy has excellent antibacterial properties (bactericidal properties), but its action is said to depend on the copper content, and the copper content is said to be at least 60 mass% or more, preferably 70 mass% or more. Yes. However, the antibacterial properties (bactericidal properties) change not only depending on the copper content but also on the Zn content and Sn, Al content. In particular, the Cu content is more than 17 mass% or 20 mass%. It has been confirmed in experiments that antibacterial properties (bactericidal properties) are improved as compared with high copper alloys. That is, in the alloy of the present invention, antibacterial properties (bactericidal properties) are further improved by containing Zn in a certain amount or more and a synergistic effect of Sn and Al. When the Zn content is less than 17 mass%, the color tone of the alloy becomes slightly reddish. Pure copper is a red-orange copper color, but a copper alloy having a copper color tone is inferior in discoloration resistance to a yellowish brass material with a large amount of Zn. Therefore, the discoloration resistance is also excellent when combined with the synergistic effect with Sn and Al by setting the Zn content to approximately 20 mass% or more. When placed in the same environment, for example, the copper-colored copper alloy when exposed for 8 hours at 60 ° C. and 95% relative humidity shows a brownish discoloration and a dull surface, whereas yellow (brass In the case of a copper alloy of (color), discoloration resistance is improved by containing Zn, such as maintaining a metallic luster at the initial stage of exposure and no noticeable discoloration.

The Zn content is at least 17.0 mass%, preferably at least 18.0 mass%, more preferably at least 20.0 mass%, in view of mechanical properties, antibacterial properties (bactericidal properties), and color tone of the alloy. Optimally, it is 21.0 mass% or more.
However, if the Zn content exceeds 34.0 mass%, many β phases appear hot (the material temperature is high) and contribute to hot workability, while cold ductility and bending work. , Corrosion resistance, stress corrosion cracking resistance and discoloration resistance are deteriorated, and antibacterial properties (bactericidal properties) are saturated or rather deteriorated. In addition, the β phase is likely to appear at the time of manufacturing a welded pipe or brazing, and there is a high possibility that many γ phases exist. The Zn content is preferably 32.0 mass% or less, more preferably 30.0 mass% or less, and more preferably 28.0 mass% or less. In addition, when there is little Zn content and it is less than 17.0 mass% (Cu content increases), mechanical strength falls, hot workability and a moldability worsen, Sn, Al, etc. Although it depends on the content, antibacterial properties (bactericidal properties) are poor. Moreover, the burr | flash at the time of cold processing, such as cold press processing, becomes large.
These various characteristics greatly affect the composition index f1, which will be described later, and the workability, corrosion resistance, discoloration resistance, mechanical strength, and the like vary depending on the value of this index.

(Sn: 0.01 mass% or more and 2.5 mass% or less)
Sn not only greatly contributes to discoloration resistance, but also has the effect of reducing deformation resistance at high temperatures, such as facilitating the formation of a β phase at high temperatures. It also contributes to punching properties such as corrosion resistance, mechanical strength, and press working. However, the Cu—Zn alloy containing Sn has a large γ phase, and the presence of the γ phase affects cold rolling properties, workability, corrosion resistance, and discoloration resistance. When Sn is contained in a copper alloy, for example, in a harsh environment viewed from a corrosive surface such as tap water, Sn oxides are preferentially formed, and complex oxides with copper or oxides of other elements However, it greatly contributes to corrosion resistance by acting as a stable protective film. The formation of an oxide is corrosion, that is, the material will change color, so the Sn oxide also affects the color change. Even in use in the atmosphere, Sn is preferentially produced as an oxide or a component in the atmosphere (a compound such as corrosive sulfur oxide or chloride). However, in the atmosphere, unlike water, it is formed as an extremely thin film rather than a thick film, so that no significant change in color tone is observed even when visually confirmed. The discoloration resistance is improved by the protective action of the film. If the protective effect of this film is too strong, it also affects antibacterial properties (bactericidal properties). The component balance based on the composition index f1 becomes important.

In order to exert the above-described effects, Sn needs to be 0.01 mass% or more, preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and most preferably 0.5 mass% or more. . In addition, if it is less than 0.01 mass%, the effect of discoloration resistance and antibacterial properties (bactericidal properties) is small, and the contribution to mechanical strength, corrosion resistance and the like is small.
On the other hand, when the Sn content exceeds 2.5 mass%, not only discoloration resistance and corrosion resistance are saturated, but also many γ phases appear at room temperature (more β phases at high temperatures) Including weldability, cold workability, cold bending workability, corrosion resistance, and the like deteriorate. Therefore, the Sn content is 2.5 mass% or less, preferably 2.0 mass% or less, more preferably 1.8 mass% or less, and most preferably 1.5 mass% or less. The relationship between discoloration resistance, antibacterial properties (bactericidal properties), and tissue (β-phase, γ-phase) is greatly related to composition indexes f1 and f2 described later, and in particular, composition indexes f2 and f3, which are relational expressions with Al. , F4 are important factors for various characteristics. Although the effect alone is small, the synergistic effect due to coexistence with Al is high, and various properties such as discoloration resistance and antibacterial properties (bactericidal properties) are good in the composition range satisfying the relational expression of f2.
In addition, Sn has almost no influence on the color tone within the range defined as described above and within a preferable range.

(Al: 0.005 mass% or more and 1.8 mass% or less)
Al, like Sn, greatly contributes to discoloration resistance. Al is one of the active elements that have low free energy of formation of oxides and are easily oxidized. Discoloration resistance is enhanced by forming an extremely thin oxide film on the surface by the addition of Al. On the other hand, when a thin oxide film is formed on the surface and the discoloration resistance is improved, the antibacterial property (bactericidal property) may be inhibited, but the antibacterial property (bactericidal property) is impaired by the proper blending of Zn and Sn. It can be held without being lost. It also has the effect of increasing the appearance of β phase at high temperatures, contributes to deformation resistance and deformability at high temperatures, and increases strength. However, although depending on the Zn and Sn contents, the addition of Al facilitates the formation of the β phase, which may cause a problem in cold workability. Furthermore, the addition of Al has the effect of reducing the viscosity of the molten metal, improving the castability, and suppressing Zn vapor generated during casting and welding. Similarly, weldability at the time of welding is improved, and a sound welded pipe and a joined structure can be obtained. On the other hand, although it becomes easy to form an oxide film when it contains a lot of Al, the oxide film becomes thick and strong, and even if bacteria are attached to the surface due to the presence of the film, it is an antibacterial (bactericidal) copper alloy. The contact between the base material (material) and the bacteria is limited, and the antibacterial property (bactericidal property) decreases. In addition, when it is actually used in the atmosphere, surface corrosion such as oxidation progresses, but the oxide film formed on the surface due to the corrosion contributes to discoloration resistance, but antibacterial (bactericidal) May become worse and may not exhibit antibacterial properties (bactericidal properties) depending on conditions. Even during welding, if a large amount of Al is contained, the weldability deteriorates rather due to the formation of a strong Al oxide film (oxide).

In order to exert the above-described effects, Al is 0.005 mass% or more, preferably 0.1 mass% or more, more preferably 0.3 mass% or more, and most preferably 0.4 mass%. That's it. In addition, if it is less than 0.005 mass%, there are few oxide films formed on the surface and the effect of discoloration resistance is small.
On the other hand, if the Al content exceeds 1.8 mass%, a strong oxide film is formed, so that discoloration resistance is improved, but antibacterial (bactericidal) or weldability is hindered. Preferably it is 1.7 mass% or less, More preferably, it is 1.6 mass% or less, Optimally, it is 1.5 mass% or less. Further, like Sn, the characteristics, structure, etc. are greatly influenced by the composition indices f1, f2, f3, f4.
In addition, Al has almost no influence on the color tone within the range defined as described above and within a preferable range.

(Pb: 0.0005 mass% or more and 0.030 mass% or less)
Pb is contained in order to improve workability such as shearing processing such as pressing and polishing. Pb hardly dissolves at room temperature in a Cu—Zn—Sn—Al-based alloy having a single-phase metal structure. Zn, Sn, Al, etc. (remainder Cu) are within the above-described composition range, composition indices f1, f2 are within an appropriate range, and cooling after completion of hot rolling or hot extrusion, cooling of heat treatment, or During the cooling of the heated portion after welding pipe welding, after forging and after brazing, Pb mainly precipitates at the grain boundaries. Since these Pb precipitate finely as Pb particles, the shearing process such as pressing and the workability such as polishing are improved.

In order to exhibit the above effects, Pb is 0.0005 mass% or more, preferably 0.001 mass% or more. On the other hand, when there is too much content of Pb, it will have a bad influence on the ductility of an alloy, hot rolling property, weldability, flat workability of a welded pipe, and bendability. The Pb content is 0.030 mass% or less, preferably 0.015 mass% or less, and optimally 0.009 mass% or less. In particular, since Pb is a harmful substance, a smaller amount is desirable.

Next, Ni added in the second invention alloy will be described.

(Ni: 0.01 mass% or more and 5 mass% or less)
Ni is an important element for suppressing discoloration resistance and suppressing the formation of β and γ phases generated during welding and hot working. Regarding the discoloration resistance, the effect of Sn and Al described above is replaced by Ni. In other words, Sn and Al improve discoloration resistance by forming a stable film such as an oxide on the surface of the material, but Ni also forms complex oxides with Cu and other elements and contributes to discoloration resistance. To do. Although depending on the amount of Ni added, even if Ni alone is added to the Cu—Zn alloy, the effect of improving the color fastness is lower than that of Sn or Al, and co-addition with Sn and Al contributes to the color fastness.
Here, if the Ni content exceeds a certain amount, hot working such as deterioration of hot water flow during casting and occurrence of surface cracks and ear cracks in hot rolling are related to Sn, Al and Zn contents. Sexuality gets worse. In addition, the press moldability is lowered, and there is a high possibility that allergy (Ni allergy) will occur, and it will be separated from the brass color and become white. However, when the content of Ni is small, the effect of improving discoloration resistance is small. Therefore, when Ni is added, the Ni content is 0.01 mass% or more, and preferably 0.3 mass% or more. In particular, when the effect of Sn and Al is replaced by Ni, when the total content of Sn and Al is 0.02 mass% or more and 0.5 mass% or less (Sn content [Sn] mass% and Al The content of Ni for obtaining properties such as 0.02 ≦ [Sn] + [Al] ≦ 0.5) between the content [Al] and good discoloration resistance is preferably 1.5 mass% or more. . Discoloration resistance and the like are exhibited by co-addition of Sn, Al, and Ni. However, when the content of Sn and Al is small, if the Ni content decreases, the effect on discoloration resistance decreases, and the Ni content is reduced to 1. When the content is 0.5 mass% or more, the decrease in the effect of Sn and Al on the discoloration resistance and the like can be compensated by the addition of Ni.
On the other hand, from the viewpoint of having a brass color, Ni allergy, and hot rolling properties, the Ni content is 5.0 mass% or less. Preferably it is 4.0 mass% or less, and optimally 3.0 mass% or less. Note that Ni contributes little to antibacterial properties (bactericidal properties), and composition indexes f1, f3, and f4 representing the blending ratio with Zn, Al, and Sn are important.

Next, Si, Ti, Mn, Fe, and Zr added in the third invention alloy will be described.

(Si: 0.01 mass% or more and 1.0 mass% or less)
The addition of Si has the effect of expanding the β phase at high temperature and improves the deformation resistance and deformability at high temperature. However, if it is included in a large amount, the β phase increases, and a lot of β phase remains even at room temperature (room temperature). Co-addition with Sn, Al increases γ phase and the like (also affected by cooling conditions). Moreover, although mechanical strength also becomes high, elongation falls and the balance of intensity | strength and elongation worsens. Below 0.01 mass%, the effect of discoloration resistance is small, and when added over 1.0 mass%, there is an effect on discoloration resistance, but not only the precipitation of β phase, but also the balance between mechanical strength and elongation. Deteriorate.
From the above, when Si is added, the Si content is 0.01 mass% or more and 1.0 mass% or less, and preferably 0.01 mass% or more and 0.5 mass% or less.

(Ti: 0.01 mass% or more and 0.5 mass% or less)
Ti does not dissolve much in the Cu—Zn—Sn—Al alloy, and some precipitates such as Ti ₂ Cu are formed. Although the addition of Ti contributes to discoloration resistance, if it is present in a large amount, the amount of precipitates increases and contributes to strength, but the elongation value decreases. In addition, the inclusion of oxide during casting becomes a problem, and a special melting method such as vacuum melting is required. If it is less than 0.01 mass%, the effect of discoloration resistance is small, and if it exceeds 0.5 mass%, the mechanical properties may be deteriorated, and the casting yield is also deteriorated.
From the above, when Ti is added, the content of Ti is not less than 0.01 mass% and not more than 0.5 mass%, preferably not less than 0.01 mass% and not more than 0.2 mass%.

(Mn: 0.01 mass% or more and 1.5 mass% or less)
Mn improves strength and wear resistance, and improves bendability and pressability. On the other hand, when there is too much content of Mn, hot rolling property will be inhibited. In addition, the contribution to discoloration resistance and antibacterial properties (bactericidal properties) is small with Mn alone, and in some cases, the antibacterial properties (bactericidal properties) may be inhibited, and the combination with Cu, Zn, Al and Sn Is important (composition index f1). Moreover, the hot metal flow property of a molten metal can be improved by containing Mn. From these points, when Mn is added, the Mn content is 0.01 to 1.5 mass%, preferably 0.1 to 1.0 mass%. Co-addition of Mn and Si must be avoided because it forms a Mn—Si compound and hinders cold workability. If Si and Mn are added together, it is preferable that Si is 0.05 mass% or less and Mn is 0.5 mass% or less.

(Fe: 0.001 mass% or more and 0.09 mass% or less)
Fe has the effect of refining the crystal grains during annealing, and in particular, when the crystal grains of the welded portion of the welded tube are made finer and high strength is obtained in the welded tube, and the welded tube is bent, the surface Will be smooth without rough skin. In order to obtain such an effect, Fe is required to be 0.001 mass% or more. Moreover, even if it contains exceeding 0.09 mass%, the above-mentioned effect is saturated and workability in cold rather falls.
From the above, when Fe is added, the content of Fe is 0.001 mass% or more and 0.09 mass% or less.

(Zr: 0.0005 mass% or more and 0.03 mass% or less)
Zr has the effect of refining hot-rolled material and crystal grains during annealing, and in particular, co-addition with P improves weldability and makes the crystal grains in the welded portion of the welded tube finer and welded. High strength is obtained in the tube, and the surface when subjected to bending is smooth without being roughened. In order to obtain such effects, Zr needs to be 0.0005 mass% or more. Moreover, even if it contains 0.03 mass% or more, the above-mentioned effect is saturated, and rather, it is taken in as an oxide at the time of casting, resulting in adverse effects such as causing casting defects.
From the above, when Zr is added, the content of Zr is 0.0005 mass% or more and 0.03 mass% or less.

Next, P, Sb, As, and Mg added in the fourth invention alloy will be described.

(P: 0.005 mass% or more and 0.09 mass% or less)
P improves corrosion resistance and improves the flowability of the molten metal. In order to exhibit this effect, the content of P needs to be 0.005 mass% or more. Moreover, since excessive P content will adversely affect cold and hot ductility, the P content is set to 0.09 mass% or less.
From the above, when P is added, the content of P is not less than 0.005 mass% and not more than 0.09 mass%.

(Sb: 0.01 mass% or more and 0.09 mass% or less)
Similarly to P, Sb is also added to improve the corrosion resistance. In order to obtain this effect, the content of Sb needs to be 0.01 mass% or more. Moreover, even if it contains exceeding 0.09 mass%, the effect corresponding to content will not be acquired, but ductility will fall on the contrary. Moreover, since Sb has a possibility of having a bad influence on a human body, it is preferable that content is 0.05 mass% or less.
From the above, when Sb is added, the Sb content is 0.01 mass% or more and 0.09 mass% or less, and preferably 0.01 mass% or more and 0.05 mass% or less.

(As: 0.01 mass% or more and 0.09 mass% or less)
As is also added to As to improve the corrosion resistance. In order to obtain this effect, the content of As is required to be 0.01 mass% or more. Moreover, even if it contains exceeding 0.09 mass%, the effect corresponding to content will not be acquired, but ductility will fall on the contrary. Moreover, since As has a possibility of having a bad influence on a human body, it is preferable that content is 0.05 mass% or less.
From the above, when As is added, the content of As is 0.01 mass% or more and 0.09 mass% or less, and preferably 0.01 mass% or more and 0.05 mass% or less.

(Mg: 0.001 mass% or more and 0.03 mass% or less)
A scrap material is often used as a part of a raw material of a copper alloy, and such a scrap material may contain an S (sulfur) component. Mg can be removed in the form of MgS in the case of manufacturing a product using scrap containing S component as an alloy raw material. Even if this MgS remains in the alloy, it does not adversely affect the corrosion resistance, discoloration resistance and the like. Further, when the S component is in the form of MgS, pressability is improved. If the scrap containing S component is used without adding Mg, S tends to be present at the crystal grain boundary of the alloy and may promote intergranular corrosion, which also reduces the corrosion resistance and discoloration resistance. However, intergranular corrosion can be effectively prevented by adding Mg. In order to exhibit the effect, the Mg content needs to be 0.001 to 0.03 mass%. Since Mg is easy to oxidize, if it is added excessively, it is oxidized at the time of casting, and forming an oxide increases the viscosity of the molten metal, which may cause casting defects such as oxide entrainment.
From the above, when adding Mg, the content of Mg is not less than 0.001 mass% and not more than 0.03 mass%.

(Cu: remainder)
Cu is a residual component such as Zn, Sn, and Al (excluding inevitable impurities), and is included as a balance of these main elements. Cu is an important element in improving mechanical strength such as tensile strength and proof stress as a copper alloy and securing characteristics such as antibacterial properties (bactericidal properties). Although it is a residual component, the content of Cu for exhibiting various characteristics is 64.0 mass% or more, preferably 65.0 mass% or more, more preferably 70.0 mass%, and most preferably 72. It is 0 mass% or more. On the other hand, if the Cu content exceeds 81.0 mass%, the mechanical strength decreases, the workability such as hot rollability and formability deteriorates, and the antibacterial properties (bactericidal properties) only deteriorate. In addition, the discoloration resistance also decreases. Note that the Cu content is 81.0 mass% or less, preferably 80.0 mass% or less, more preferably 78.0 mass%, and most preferably 77.0 mass% or less.

(Inevitable impurities)
Inevitable impurities include Cr, Ag, Ca, Sr, Ba, Sc, Y, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, Se, Te, Rh, Ir, Pd, Examples thereof include Pt, Au, Cd, Ga, In, Li, Ge, Tl, Bi, S, O, Be, N, H, Hg, B, and rare earth. The total amount of inevitable impurities including these is preferably 0.5 mass% or less. When inevitable impurities are contained in a large amount of 0.5 mass% or more in total amount, it also affects the metal structure, reduces corrosion resistance, antibacterial properties (bactericidal properties), etc., reduces cold workability, such as reducing elongation, Moreover, it is desirable not to include such as increasing deformation resistance in the hot state. Inevitable impurities indicate elements that are not intentionally included.

(Composition index f1)
Zn content [Zn] mass%, Sn content [Sn] mass%, Al content [Al] mass%, and each content of Si, Ti, Ni, Mn, Fe and Zr [Si] mass%, [Ti] mass%, [Ni] mass%, [Mn] mass%, [Fe] mass%, and [Zr] mass% multiplied by a coefficient for each element, and the total relational expression And its numerical value affects the area ratio of β phase and γ phase present in the metallographic structure of welded pipes, plates, bars, forgings, castings, and cold workability (cold rolling, cold drawing, etc.) Plastic processing), bending workability of welded pipes and plates, strength, corrosion resistance, discoloration resistance and antibacterial properties (bactericidal properties). Therefore, the composition index f1 is an important relational expression obtained by comprehensively quantifying these characteristics and properties.

When the value of the composition index f1 is lower than 24, hot deformation resistance such as hot rolling, hot extrusion or hot forging becomes high. Further, the strength of the material is low, discoloration resistance is poor, and press workability is also deteriorated. In hot rolling, an ingot heated to a predetermined temperature (for example, a plate thickness of 190 mm) is gradually rolled by a rolling mill to reduce the plate thickness. However, since the rolling resistance with a small power has a large deformation resistance, the processing rate in one pass cannot be made large. Therefore, the number of machining passes increases, and the material becomes thin and the material length is long in the second half of hot working (the latter half of hot rolling in which the final thickness is 25 mm or less when hot rolling is performed to about 12 mm). Therefore, the processing time of hot rolling becomes long. For this reason, not only does the temperature drop of the material increase, the deformation resistance increases, the load on the rolling mill increases, but it is also impossible to obtain a rolled material with a desired thickness, which adversely affects hot rolling properties. . In addition, when the content of each element including Zn, Sn, and Al and the total content weighted for each element: f1 is low, discoloration resistance is not sufficient. Similarly, antibacterial properties (bactericidal properties) are also inferior. In addition, workability in the case of performing shearing such as press working is deteriorated such that burrs are easily generated. In addition, when the material strength is low and it is used for a member that requires strength, it is necessary to increase the material thickness, and there is a problem in cost. On the other hand, when the value of the composition index f1 is low, the thermal conductivity is increased, the weldability is deteriorated, the mechanical strength is lowered, and the balance with ductility is deteriorated. Copper alloy has good thermal conductivity, but if it has good thermal conductivity (replaced by electrical conductivity, there is a proportional relationship between thermal conductivity and conductivity, which is an index of electrical conductivity), welding Since heat diffuses at the time of brazing or brazing, it is necessary to heat over a wide range, resulting in poor weldability and brazing. In order to perform good welding and brazing, 25% IACS or less is desirable in terms of conductivity.
As described above, the value of the composition index f1 is 24 or more, preferably 26 or more, more preferably 28 or more, and optimally 29 or more from the viewpoint of hot rollability, press workability and strength.

If the value of the composition index f1 exceeds 40, the area ratio of the β phase at a high temperature state such as hot rolling, hot extrusion, tube welding, hot forging, etc. increases, and the β phase at the normal temperature (room temperature), γ The area ratio of the phase is also increased. Therefore, although the material strength increases, the balance between the material strength (tensile strength) and the elongation is poor, and the relational expression M1 = σ × (1 + ε / 100) (σ is the tensile strength and ε is a value indicating the elongation). Get smaller. In addition, the increase in the β phase reduces the hot deformation resistance and improves the hot workability, but the cold workability is improved by the presence of a large amount of β and γ phases in the structure at room temperature (room temperature). It drops significantly. Ductility is low during cold rolling, cold drawing, etc., and cold working such as bending of pipes and plates, resulting in cracks during processing and insufficient processing rates. There are adverse effects. Furthermore, the dezincification corrosion resistance and stress corrosion cracking resistance, which are corrosion resistance, are deteriorated. The discoloration resistance is the same. When the numerical value reaches the upper limit, the discoloration resistance is saturated and rather lowered. Furthermore, the antibacterial property (bactericidal property) that is a feature of copper alloys is not saturated, but decreases.

In addition, a welded pipe is manufactured by electro-sewing processing, but the weldability is deteriorated and the yield at the time of manufacturing the welded pipe is deteriorated. Further, since the welded pipe is locally accompanied with temperature rise and melting, the thickness of the pipe is thin and the cooling rate is high, the area ratio of β phase and γ phase in the metal structure of the welded pipe is increased. Welded pipes may be used after being bent 90 ° (for example, with a radius of curvature of 40 mm) or complex bending depending on the application, causing problems such as cracking in the bent part or inability to process into a predetermined bending shape. Arise. If the bending process is performed by heating the bent part or the like, the bending process can be performed without causing a crack, but the strength of the part is lowered. In addition, since the heated portion is annealed, the crystal grain size grows, and there is a possibility that problems such as rough skin, strength, and fatigue may occur during bending. In addition, discoloration resistance, corrosion resistance, and antibacterial properties (bactericidal properties) are deteriorated, and further, the cost is increased. Further, in the production of welded pipes, if the value of the composition index f1 is higher than 40, the β phase or γ phase remains in the joint portion and the portion that receives the heat of welding, and the subsequent production processes such as cold rolling and cold There is a problem with drawing. Moreover, discoloration resistance and antibacterial properties (bactericidal properties) deteriorate.

As described above, in consideration of discoloration resistance, antibacterial properties (bactericidal properties), cold workability, bendability and the like, the value of the composition index f1 is 40 or less, preferably 38 or less, more preferably 36 or less. The optimum value is 34 or less. On the other hand, in consideration of hot rollability, press workability and strength, the value of f1 is 24 or more, preferably 26 or more, more preferably 28 or more, and optimally 29 or more.
That is, the composition index f1 is in the range of 24 ≦ f1 ≦ 40, preferably in the range of 26 ≦ f1 ≦ 38, more preferably in the range of 28 ≦ f1 ≦ 36, and optimally 29 ≦ f1 ≦ 34. Within range.

Incidentally, in the composition index f1, a large coefficient is given to Sn and Al. The main reason is that both Sn and Al have a great influence on discoloration resistance, corrosion resistance, and antibacterial properties (bactericidal properties). Furthermore, when Sn is locally melted during welding, segregation of Sn occurs, and a small amount of Sn. The β phase and γ phase remain, and the amount of β phase and γ phase increases as the concentration increases. In addition, the β phase and γ phase are likely to remain even during hot working. Moreover, since the β phase and γ phase containing a large amount of Sn are brittle and hard, they affect cold workability and bending workability. Al shows the same tendency as Sn in terms of metal structure, but the degree thereof is small, works positively on weldability, and alleviates the influence of Sn. In particular, a synergistic effect of Sn and Al is added to each property including discoloration resistance and antibacterial properties (bactericidal properties), which are the subject of the present invention.

Ni added in the second invention alloy has a small coefficient of composition index f1 and is negative. The discoloration resistance is small compared to the synergistic effect of Sn and Al, but has a certain effect, and therefore depends on the Ni content. Moreover, Ni has the effect | action which suppresses the production | generation of the beta phase at the time of welding by hot containing by containing Sn and Al, and a gamma phase. In particular, when the composition index f1 shows a large value, it is possible to maintain the discoloration resistance by using Ni instead of Sn and Al, and to use it for suppressing the formation of β and γ phases. It is. Although the coefficient is small and the action seems to be small, the effective use of Ni makes it possible to improve discoloration resistance and antibacterial properties (bactericidal properties) while improving processability.

In addition, since Si, Ti, Mn, Fe, and Zr added in the third invention alloy affect various properties such as workability, discoloration resistance, and antibacterial properties (bactericidal properties), the composition index f1 , Each element has been multiplied by a factor.
On the other hand, P, Sb, As, and Mg added in the fourth invention alloy are small in amount compared to other elements, and have a significant effect on mechanical properties, corrosion resistance, discoloration resistance, etc. Since the influence is small (that is, the coefficient is 0 or a number close to 0), it is not included in the relational expression of the composition index f1.

For impurities inevitably included, the composition index f1 is hardly affected when the total amount of impurities is less than 0.5 mass%. When the total amount of inevitable impurities exceeds 0.5 mass%, the content of inevitable impurities is set to [X] mass%, and f1 = [Zn] + 5 × [Sn] + 3 × [Al] + 2.5 × [Si] + 1.0 × [Ti] −0.5 × [Ni] + 0.5 × [Mn] + 0.2 × [Fe] + 0.1 × [Zr] + [X] is 24 ≦ f1 ≦ 40 It may be within the range.

(Composition index f2)
Sn and Al are also related to the Zn content, but the composition index f2 is based on the premise that Al: 0.01 to 1.8 mass% and Sn: 0.01 to 2.5 mass%. It has a great influence on discoloration resistance, corrosion resistance and antibacterial properties (bactericidal properties), and affects punchability such as weldability, hot workability, cold workability, bending workability, and press work.
When the value of the composition index f2 = [Sn] + 2 × [Al] is less than 1.2, it does not greatly contribute to the discoloration resistance, the punching property such as press working is deteriorated, and the antibacterial property (bactericidal property) is also inferior. On the other hand, when the composition index f2 exceeds 4.0, discoloration resistance is improved, but antibacterial properties (bactericidal properties) are reduced, and weldability, hot workability, cold workability, and bending workability are also improved. descend. In addition, under the co-addition of Al and Sn, Al is given a larger coefficient than Sn. Al is contained in a small amount and exhibits an effect particularly on discoloration resistance. As the antibacterial properties (bactericidal) begin to deteriorate. Considering such characteristics, the value of f2 is preferably 1.3 or more, and more preferably 1.5 or more. Moreover, 3.5 or less is preferable and 3.2 or less is more preferable. From the viewpoint of the synergistic effect of Al and Sn, when Al is contained in an amount of 0.4 mass% or more, and Sn is contained in an amount of 0.5 mass% or more, it has a remarkable effect.
That is, the composition index f2 is in the range of 1.2 ≦ f2 ≦ 4.0, preferably in the range of 1.3 ≦ f2 ≦ 3.5, and more preferably in the range of 1.5 ≦ f2 ≦ 3.2. Within the range.
As for the impurities inevitably included, the composition index f2 is hardly affected when the total amount of impurities is less than 0.5 mass%. Even when the total amount of inevitable impurities exceeds 0.5 mass%, the composition index f2 may be within the above range.

(Composition index f3)
When a part of Al and Sn is replaced by Ni as in the second invention alloy, the composition index f3 = 0.7 × [Ni] + [Sn] + 2 × [Al] is 1.2 ≦ f3 ≦ 4 Within the range of 0.0, the alloy has good discoloration resistance, corrosion resistance, and antibacterial properties (bactericidal properties), and good hot workability, cold workability, bending workability, and punching workability such as press work. It becomes. Further, from the composition index f3, the effect of Ni, such as discoloration resistance, is lower than that of Al or Sn, and it is necessary to contain a large amount of Ni, and the coefficient is small.
Similar to the composition index f2, the composition index f3 is 1.2 or more, preferably 1.3 or more, and more preferably 1.5 or more considering various characteristics. On the other hand, it is 4.0 or less, preferably 3.5 or less, and more preferably 3.2 or less.
That is, the composition index f3 is in the range of 1.2 ≦ f3 ≦ 4.0, preferably in the range of 1.3 ≦ f3 ≦ 3.5, and more preferably in the range of 1.5 ≦ f3 ≦ 3.2. Within range.
As for the impurities inevitably contained, the composition index f3 is hardly affected when the total amount of impurities is less than 0.5 mass%. Even when the total amount of inevitable impurities exceeds 0.5 mass%, the composition index f3 may be within the above range.

(Composition index f4)
Further, when Sn and Al are added together as described above, they contribute to various properties such as discoloration resistance, antibacterial properties (bactericidal properties) and strength, and the composition index f4 = [Sn] × [Al] +0. 1 × [Ni] is also an important factor. When Ni is not added, the composition index f4 = [Sn] × [Al].
When the composition index f4 is less than 0.02, discoloration resistance and strength are not sufficient even when Sn and Al are added together. Therefore, the composition index f4 is 0.02 or more, preferably 0.1 or more, more preferably 0.2 or more, and most preferably 0.3 or more. On the other hand, when the composition index f4 exceeds 1.8, not only the additive synergistic effect by co-addition is saturated but also bad aspects such as a decrease in cold workability appear. Therefore, the composition index f4 is 1.8 or less, preferably 1.6 or less, more preferably 1.4 or less, and most preferably 1.3 or less.
That is, the composition index f4 is in the range of 0.02 ≦ f4 ≦ 1.8, preferably in the range of 0.1 ≦ f4 ≦ 1.6, more preferably in the range of 0.2 ≦ f4 ≦ 1.4. The optimum range is 0.3 ≦ f4 ≦ 1.3.
As for the impurities inevitably included, the composition index f4 is hardly affected when the total amount of impurities is less than 0.5 mass%. Even when the total amount of inevitable impurities exceeds 0.5 mass%, the composition index f4 may be within the above range.

(Metal structure)
The β phase has different area ratios depending on the Zn amount (Cu amount), Sn amount, and Al amount, and the value of the composition index f1 becomes important. The β phase appears in the Cu—Zn alloy when the material temperature becomes high when the Zn content is 32.5 mass% or more as seen from the Cu—Zn binary equilibrium diagram. Although the β phase appears at a high temperature, it transforms from the β phase to the α phase when the material is cooled, and the β phase decreases. Further, when the Zn content is 39 mass% or more, the β phase exists without disappearing even at room temperature. However, if it is manufactured by a general manufacturing method, it becomes a non-equilibrium state, and the amount of Zn remaining in the β phase shifts to the low concentration side instead of the equilibrium state diagram. Sn and Al are elements that facilitate the appearance of the β phase at high temperatures. Furthermore, since Sn and Al have a metal structure and phase structure that are further away from the equilibrium state in practical production, the composition of Zn, Sn, Al, and the like is determined in an appropriate range by the composition index f1 and the like.

The β phase has a function of reducing deformation resistance at high temperatures in copper alloys and improving workability and deformability in hot conditions. However, if the β phase is present in the matrix at room temperature (room temperature), the β phase is harder than the α phase, which is the majority of the matrix, and the strength is high, so that cold workability is lowered. Sn and Al are harder because they are distributed more in the β phase than in the α phase. Specifically, in cold bending and plastic processing such as rolling, cracks occur in parts where the radius of curvature of the bending is severe, or ear cracks (cracks on the end face of the ingot) occur during cold rolling. To do. In addition, the corrosion resistance is very poor compared to the α phase, which causes dezincification corrosion and stress corrosion cracking. In particular, if the β phase is large, the rolled phase or extruded material may cause the β phase to continue in parallel with the rolling direction or the extrusion direction, and the corrosion depth increases due to the continuous β phase having poor corrosion resistance. Moreover, it has a bad influence also about discoloration resistance and antibacterial property (bactericidal property). Note that the β phase that appeared at high temperature in the Cu—Zn—Sn—Al based alloy is transformed into the α phase or the α phase and the γ phase by cooling as in the Cu—Zn alloy, but depending on the amount of Zn and the amount of Sn and Al. Affected by the compositional indices f1, f2, f3, f4.

On the other hand, when shearing such as press working is performed due to the presence of the β phase, it is better that a small amount of the β phase and a γ phase described later are present. The α phase containing Sn and Al having a high Zn concentration and satisfying the conditions of f2, f3, and f4, that is, the α phase immediately before the appearance of the β phase does not include the β phase or the γ phase. The pressability is improved as compared with the α phase containing no Sn or Al or a small amount even if it is contained, compared with the α phase having a low Zn concentration. In addition, the presence of a small amount of β phase serves to suppress the growth of crystal grains of the α phase of the matrix when the material temperature rises, such as heat treatment, resulting in smaller crystal grains. Crystal grains affect mechanical properties (strength), and the smaller the crystal grain size, the higher the strength. As described above, various characteristics are affected in various ways by the presence of the β phase.

Similarly, this alloy, which has a compositional index f1, f2, f3 and f4 and is in a state immediately before the appearance of the β phase and has only the α phase in the metal structure, has discoloration resistance and antibacterial properties (bactericidal properties). Good bendability and weldability.
From the above, the area ratio of the β phase at room temperature (room temperature) is 0.9% or less, preferably less than 0.5%, and more preferably in the vicinity of 0% or 0%. That is, in order to achieve the object of the present invention, from the viewpoint of the metal structure, the metal structure of the α phase only immediately before the appearance of the β phase, or the matrix is the α phase, and the β is about 0.1% in area ratio. A metal structure containing a phase is good.

Γ phase is generated by transformation of β phase that appeared at high temperature into α phase and γ phase by eutectoid reaction. The γ phase is harder than the β phase and has a brittle nature. A γ phase formed of a Cu—Zn—Sn—Al based alloy (for example, a γ phase composed of 50 mass% Cu-40 mass% Zn-10 mass% (Sn + Al)) contains a lot of Sn and Al. It becomes harder. Therefore, when compared with the same area ratio, the γ phase has a greater effect on the elongation when the tensile test is carried out than the β phase, and the cold workability is lowered. Further, although the γ phase has better corrosion resistance than the β phase, it is worse than the α phase of the matrix, so that the overall corrosion resistance (dezincification corrosion, stress corrosion cracking, etc.) is reduced. The γ phase is also observed in the Cu—Zn binary alloy and appears when the Zn content is 48.9 mass% or more. However, in the Cu—Zn—Sn—Al based alloy, unlike the γ phase of the Cu—Zn binary alloy, the Sn phase is Sn. , Al will be contained, it is harder and more brittle, and the influence on cold workability will be greater. A small amount of γ phase improves press workability.

Like the β phase, the γ phase is affected by the amount of Zn, Sn, and Al, and in order to keep the appropriate amount of γ phase, it is necessary that the values of the composition indices f1 and f2 are in a favorable range. It is important in view of various characteristics. In view of the area ratio of the γ phase, it is necessary to be 0.7% or less, preferably less than 0.4%, and more preferably in the vicinity of 0% or 0%. From the viewpoint of the metal structure, in the same way as the β phase, in order to have good discoloration resistance, antibacterial properties (bactericidal properties), and good bending workability and weldability, the metal of only the α phase immediately before the appearance of the γ phase. A structure or a metal structure containing an α phase and a γ phase with an area ratio of about 0.1% is preferable.

If the β phase and the γ phase are present at room temperature (room temperature), the cold workability and corrosion resistance are adversely affected as described above. If these β phase and γ phase are present at room temperature (room temperature) at the same time, the synergistic effect of these β phase and γ phase is greater than the presence of each of them alone. In view of this influence, when the area ratio of the γ phase is (γ) and the area ratio of the β phase is (β), the value of the area ratio index f5 = 2 × (γ) + (β) is 1.5. If it exceeds the above range, the cold workability and the corrosion resistance are deteriorated.
Therefore, the area ratio index f5 is 1.5 or less, preferably 1.2 or less, more preferably f3 is 1.0 or less, and most preferably 0% or near 0%.

In the alloy of the present invention, the β phase area ratio in the α phase matrix is 0 to 0.9%, preferably 0 to 0.5%. Tissue is preferred. However, the grain boundary of α phase and the phase boundary of α-β increase the concentration of Zn, Sn, Al and other inevitable impurities that promote the formation of β phase, and the corrosion resistance becomes unstable and strengthened. There is a need to. For this reason, addition of Mg, Sb, As, and P is necessary. Note that the β phase includes a β ′ phase generated by the order-disorder transformation.

Here, in the discoloration-resistant copper alloys (first to fourth invention alloys) according to the first to fourth embodiments of the present invention, the viable cell rate after 10 minutes in the antibacterial test is the viable cell rate of pure copper. Is equivalent or lower. That is, it has antibacterial properties (bactericidal properties) equivalent to or better than pure copper.
Here, the viable cell rate is evaluated by a test method compliant with JIS Z 2801 (antibacterial processed product-antibacterial test method / antibacterial effect).

(Strength / elongation balance index M1)
In the discoloration-resistant copper alloys (first to fourth invention alloys) according to the first to fourth embodiments of the present invention, when the tensile strength σ and the elongation ε are assumed, the strength / elongation balance index M1 = σ It is preferable to consider x (1 + ε / 100).
High strength makes it possible to reduce the thickness and weight of the product used, which is advantageous in terms of cost, but high-strength materials have low elongation values, and plastic working such as cold workability and bending work. The balance between strength and elongation becomes important. If the strength / elongation balance index M1 = σ × (1 + ε / 100) is 440 or more, the balance between strength and elongation is good, and cold workability, bending work, strength, and the like are ensured to the minimum necessary. The strength / elongation balance index M1 is preferably 490 or more.

(Average crystal grain size)
Further, in the discoloration-resistant copper alloy (first to fourth invention alloys) according to the first to fourth embodiments of the present invention, it is preferable to consider the average crystal grain size.
The average grain size is preferably 0.003 to 0.070 mm (3 to 70 μm) because it affects punchability, bendability, strength, corrosion resistance, and the like. When the average crystal grain size is larger than 0.070 mm, roughening (roughness) occurs when bending is performed. In addition, when punching, the quality of the product is deteriorated, such as a large amount of baldness and burr and rough skin in the vicinity of the punched portion. Further, the strength is lowered, and when used for a handrail, a door handle or the like, the strength is insufficient, and repeated fatigue becomes worse. Since it is necessary to increase the thickness (plate thickness) due to insufficient strength, the weight cannot be reduced, and corrosion resistance and discoloration resistance tend to deteriorate. Preferably, it is 0.050 mm or less, and optimally 0.040 mm or less. On the other hand, if the average crystal grain size is less than 0.003 mm, a problem occurs in bendability, and 0.005 mm or more, and further 0.010 mm or more is optimal. In the case of a welded pipe that is not subjected to cold drawing, strength is required for use, and therefore the average crystal grain size of the strip of the welded pipe material is preferably 0.005 to 0.020 mm.

Next, a method for producing a discoloration-resistant copper alloy (first to fourth invention alloys) according to the first to fourth embodiments of the present invention, a copper alloy member made of the first to fourth invention alloys, and a copper alloy member A manufacturing method will be described.

Depending on the content of Zn, Sn, Al, etc., the β phase may appear at high temperatures during hot working, and it transforms from the high temperature region to the α phase during the cooling phase, or the α phase and the γ phase co- The γ phase appears by the precipitation reaction. In order to keep the amount of β phase and γ phase present in non-equilibrium below the predetermined amount in the final plate and welded pipe, the total amount of β phase and γ phase should be 5% at the stage after hot working. Hereinafter, it should be preferably 3% or less. The starting temperature of hot working such as hot rolling is 760 to 930 ° C. depending on the composition, and the rolled material is finished to a thickness of 10 to 20 mm. If it is an extruded material, it is extruded to a predetermined size. In the case of a rolled material, after hot rolling, it is annealed through milling and cold rolling. When cold-rolled material is heat-treated (softening heat treatment such as annealing) in a continuous annealing cleaning line, the highest temperature reached during annealing is 550 to 780 ° C, and it is heated to a high temperature range such as hot rolling and hot extrusion. Since the heating time is short, the β phase in the matrix does not increase. However, in the case of batch-type annealing, attention should be paid because the γ phase may increase when the first annealing is performed at a temperature of 450 ° C. or lower. Preferably, batch annealing is desirable under conditions of 480 ° C. or higher.

In hot forging, when the material temperature is raised, the deformation resistance decreases, and when the β phase appears at a high temperature, the deformation resistance at high temperature decreases and the deformability improves. Therefore, the material temperature is increased to 700 to 880 ° C. Will be implemented. When the β phase is included in a large amount of 10% or more during hot forging, the β phase is reduced by setting the cooling rate to 650 ° C. after forging to 3 ° C./second or less or 10 ° C./second or less. In hot forging, although depending on the shape of the forging, the cooling rate is fast in the thin part after forging, and the cooling rate is slow in the thick part, but the cooling rate in the fast part is 1 ° C / second or less. If so, the overall β phase is reduced.

When forming the welded pipe, the joint portion of the welded pipe is instantaneously melted, so that the β phase is likely to appear. Further, when joining is performed by welding, brazing, or the like, the welded portion is instantaneously melted, and the brazed portion is heated to a temperature of 800 ° C. or higher, so that the β phase is likely to appear. In addition, when the plate thickness is thin, the cooling condition is accelerated and the β phase tends to remain. For this reason, the proportion of the β phase and γ phase in the metal structure of the welded pipe material must be set to 0% or 0.5% or less in advance.

Here, the discoloration-resistant copper alloys (first to fourth invention alloys) according to the first to fourth embodiments of the present invention are, for example, lever handles, door handles, etc. used in hospitals and public facilities, such as nurse skirts. Or it is used for the rail installed in a bed, and a side rail, but many of them are used for them. In these applications, the pipe material is used after being subjected to 90-degree bending, flattening, caulking, etc. In the case of fences, side rails, lever handles, a large load is applied during use, so high strength and ductility, and Safety and antibacterial properties (bactericidal properties) are required. In the case of this alloy, a welded pipe (electrically welded pipe) is preferable as the pipe material. In addition to being excellent in discoloration resistance and antibacterial properties (bactericidal properties) in the welded pipe, the weldability is good and the strength of the welded pipe is high. It is necessary to have a good balance between strength and ductility. The alloy of the present invention can have the above characteristics by satisfying the requirements of the composition range of each element, the composition index f1, f2, f3, f4, the area ratio index f5 and the occupied area of the β phase and the γ phase.

In addition, as an evaluation of the welded pipe, a spread test, a flat test, and a 180 ° bending test can be applied. When the welded pipe is expanded to 1.25 times the diameter of the original welded pipe in the expansion test, the welded part is not cracked. In the flat test, the welded part has a thickness of 3 t (three times the wall thickness: t Is flattened to the thickness of the pipe material), it is proved that the welded portion is sound because there is no crack in the welded portion. When the welded pipe is bent at 180 degrees, there is no practical problem if the bending R is within three times the diameter and no cracking occurs. And preferably, if the tensile strength of the welded pipe is 350 MPa or more, more preferably 400 MPa or more, or the proof stress is 120 MPa or more, preferably 150 MPa or more, more preferably 200 MPa or more, it is said that the strength is good, and it is made of iron. It can be made thinner than the finished pipe.

In each manufacturing method, high-temperature heating, that is, hot working (rolling, extrusion, forging, etc.) is heated to 700 to 930 ° C., or in a welded pipe, it melts instantaneously, but each component of the material has a composition index f1. By satisfying, the β phase and the γ phase fall within a predetermined amount. If there is a large amount of residual β phase, the mechanical strength increases, but the elongation decreases, the balance between strength and elongation is poor, cold workability is poor, and antibacterial (bactericidal) and corrosion resistance are also adversely affected. Effect. In order to reduce the area ratio of the β phase, various characteristics can be improved by setting the composition index f1 or the like to an appropriate range.
Door handles, elbows, and the like are sometimes made of forged products, and are required to have no cracks with an appropriate forging load. In the alloy of the present invention, forging characteristics, discoloration resistance, antibacterial properties are satisfied by satisfying the requirements of the composition range of each element, composition index f1, f2, f3, f4, area ratio index f5, and occupied area of β phase and γ phase. (Bactericidal) can be provided.

As described above, welded pipes are used for side rails, fences, etc., but they are joints between pipes, and other pipes of the same kind and different materials, pipes, forged products, plates, bars, wires, castings, etc. Are joined by welding, soldering, brazing, or the like to form one member (for example, a side rail). Therefore, at least the alloy of the present invention needs to have good bondability, weldability, solderability, and brazeability. In the alloy of the present invention, by satisfying the requirements of the composition range of each element, composition index f1, f2, f3, f4, area ratio index f5 and the occupied area of β phase and γ phase, bonding property, discoloration resistance, antibacterial property (Bactericidal) can be provided.

As described above, the discoloration-resistant copper alloys (first to fourth invention alloys) according to the first to fourth embodiments of the present invention have discoloration resistance, corrosion resistance, and antibacterial properties (bactericidal properties), and are welded pipes. Forged products, good bonding, mechanical strength, good ductility, door handles, door knobs, door push plates, handrails, bed rails, sideboards, tabletops, chair backrests, nur skirt handles, It can be suitably used for building materials for walls used for stationery supplies such as pen grips, keyboards, mice, sinks, straps, switches, switch covers, elevators, and the like.

As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It is possible to change suitably in the range which does not deviate from the technical idea of the invention.

Hereinafter, the results of a confirmation experiment conducted to confirm the effect of the present invention will be shown. The following examples are for explaining the effects of the present invention, and the configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

Using the first invention alloy, the second invention alloy, the third invention alloy, the fourth invention alloy, and the copper alloy having a composition for comparison, samples were prepared by changing the manufacturing process. As comparative copper alloys, C1020, 2600 defined by JIS H 3100 and C4622 defined by JIS H 3250 were used.

The production process P1 was conducted in a laboratory test for the purpose of examining the influence of the composition, and the process P1-1 was a rolled material and the process P1-2 was an extruded material.
The production process P2 was aimed at production in a mass production facility as a rolled material, and also aimed at investigation with a welded pipe.
The production process P3 was intended for production in mass production equipment as an extruded material, and for the purpose of investigating forgings and joining such as brazing and welding.

The production process P1-1 was performed as follows.
Raw materials prepared by adjusting various components of electrolytic copper, electrolytic zinc, high-purity Sn, Al, and other commercially available pure metals were dissolved in an electric furnace. Then, the molten metal was poured into a mold mold having a width of 70 mm, a thickness of 35 mm, and a length of 200 mm to obtain a plate-shaped ingot as a test sample. The plate-shaped ingot was made by removing the entire cast skin portion and oxides by cutting to prepare a sample having a width of 65 mm, a thickness of 30 mm, and a length of 190 mm. The ingot was heated to 800 ° C., hot-rolled to a thickness of 8 mm in 3 passes, and cooled by air cooling and forced air cooling using a cooling fan. After removing the oxide on the surface of the hot-rolled sample by polishing, it was cold-rolled to a thickness of 1.0 mm, and the furnace set temperature in a nitrogen atmosphere using a continuous furnace (manufactured by Koyo Thermosystem: 810A). By changing the feed rate, heat treatment was performed under the conditions of a maximum temperature of 650 ° C. and a holding time in the temperature range from a temperature 50 ° C. lower than the maximum temperature to a maximum temperature of 0.3 min. These heat treatments are carried out on the assumption that mass-produced materials are manufactured in a continuous annealing cleaning line, and it is possible to perform the heat treatment under the same heat treatment conditions as in the continuous annealing cleaning line. After the heat treatment, it was further cold-rolled to 0.9 mm (processing rate 10%) to prepare a sample.

The production process P1-2 was performed as follows.
Raw materials prepared by adjusting various components of electrolytic copper, electrolytic zinc, high-purity Sn, Al, and other commercially available pure metals were dissolved in an electric furnace. Thereafter, the molten metal was poured into a mold having a diameter of 100 mm and a height of 200 mm to obtain a rod-shaped ingot. The cast cast ingot was made by removing the cast surface portion and oxides on the entire surface by cutting to prepare a sample having a diameter of 90 mm and a height of 190 mm. This sample was heated to 800 ° C. and extruded to a diameter of 21 mm by a 500-ton press extruder to obtain a bar having a length of 2000 mm. This extruded rod was drawn to a diameter of 20 mm to obtain a cold drawn material (processing rate: 9.3%).

The production process P2 was performed as follows.
A raw material adjusted to a predetermined component is melted in a groove type low frequency induction heating furnace to produce a plate-shaped ingot having a thickness of 190 mm, a width of 840 mm, and a length of 2000 mm, and the ingot is heated to 800 ° C. And hot rolled to a thickness of 12 mm (13 passes). Each surface of the rolled material was chamfered (thickness: 11.2 mm) and then processed to 1.0 mm by cold rolling. This material was heat-treated in a continuous annealing cleaning line with a heat treatment material having a maximum temperature of 650 ° C. and a holding time in a temperature range from a temperature 50 ° C. lower than the maximum temperature to a maximum temperature of 0.3 min. The heat-treated material was cut into a width of 87 mm and 80 mm by a slitter, and a strip (material) of a welded tube was produced.

The welded pipe was manufactured in two ways. The width of the strip varies depending on the welding method. When a welded tube is manufactured by heating with a high-frequency induction heating coil, the width of the strip is 87 mm, and when performing TIG welding, the width of the strip is 80 mm, and the thickness is 1.0 mm. )) Was used. In the production of welded pipes using a high-frequency induction heating coil, the material is supplied at a feed rate of 60 m / min, plastically processed into a circle by a plurality of rolls, and the cylindrical material is heated by a high-frequency induction heating coil. Join by joining both ends of the strip. The bead portion of the joint portion was removed by cutting with a cutting tool (cutting blade) to obtain a welded tube having a diameter of 25.4 mm and a wall thickness of 1.08 mm. Due to the change in wall thickness, when forming into a welded tube, a substantial percentage of cold work is applied. In the manufacture of welded pipes by TIG welding, the strips are supplied at a feed rate of 2 m / min, the plate-like shape is plastically deformed into a circle by a plurality of rolls (same as the heating method using a high-frequency heating coil), and both end surfaces are brought into contact with each other. The portions are joined by TIG welding while supplying Ar gas. The bead portion of the welded portion was cut and removed online with a tool (cutting blade). By this method, a welded tube having a diameter of 25.4 mm and a wall thickness of 1.0 mm was obtained. In addition, although the thickness of the welded pipe by the induction heating coil was changed, there was almost no change in the TIG welding.
In addition, the rolled material after heat treatment in the continuous annealing cleaning line was rolled to a thickness of 0.9 mm (working rate: 10%) by cold rolling in order to evaluate various properties.
In addition, C2600 (70Cu / 30Zn brass) and C1020 (oxygen-free copper) with a plate thickness of 1 mm were used as comparative materials, and the maximum temperature reached was achieved by adjusting the furnace set temperature and feed rate in a nitrogen atmosphere using a continuous furnace. The heat treatment was performed at 650 ° C. and a holding time in the temperature range from the temperature 50 ° C. lower than the highest temperature to the highest temperature at 0.3 min. Each heat-treated plate was cold-rolled to a plate thickness of 0.9 mm (processing rate: 10%).

Manufacturing process P3 was performed as follows.
The raw material adjusted to a predetermined component is melted in a groove-type low frequency induction heating furnace to prepare a bar ingot having a diameter of 240 mm and a length of 700 mm, and the ingot is heated to 800 ° C. An extruded material having a diameter of 21 mm was prepared. The extruded material was cold drawn to a diameter of 20 mm (processing rate: 9.3%) to obtain a drawn material.
The drawn material was cut to a length of 200 mm, heated to 800 ° C. in a furnace, and hot forged into a door handle shape (L shape). Immediately after forging, the cooling rate at 800 ° C. to 650 ° C. was 1.5 ° C./second.
As a comparative material, C4622 (63Cu-35.9Zn-1.1Sn) having a diameter of 21 mm was manufactured in the same process as the manufacturing process P3, and cold-drawn to a diameter of 20 mm (processing rate: 9.3%).

No. in step P1-1. 1 to 8, 1-1 to 1-12, 2-1 to 2-10, 3-1 to 3-6, 4-1, 4-2, no. A1-A7, A9-A11, A1-1, A1-2, A2-1-A2-4, A3-1-A3-5, A4-1, A4-2, and No. B1 and B2 are No. in the process P1-2. 9-11, 1-13-1-15, 2-11, 3-7, 3-8, no. A8, A12, A13 and No. B3 was prepared and subjected to hot workability, structure observation, mechanical property measurement, discoloration resistance test, corrosion resistance test and the like.
Further, in the process P2, no. 12, 13 and 17 were prepared and heat-treated in a continuous annealing cleaning line, and then the rolled material (working rate 10%) having a thickness of 0.9 mm by cold rolling and the heat-treated material were welded by welding pipe processing. Prototyped. The rolled material was subjected to hot workability, structure observation, mechanical property measurement, discoloration resistance test, corrosion resistance test and the like as in Step P1-1. In addition to these, we also conducted tests to evaluate the soundness of welded pipes, such as flattening tests and spreading tests, and weldability evaluations.
It is No. by process P3. 14, 15 and 16 extruded materials (drawing materials) were produced. For these, the same evaluation as in Step P1-2, a brazing test and a forged product were produced, and the forgeability and the structure of the forged product were confirmed.

<Color tone and color difference>
For the surface color (color tone) of the copper alloy to be evaluated in the discoloration resistance test described later, an object color measurement method in accordance with JIS Z 8722-2009 (color measurement method—reflective and transmissive object color) was performed. It is shown in the L ^* a ^* b ^* color system defined by Z 8729-2004 (color display method—L ^* a ^* b ^* color system and L ^* u ^* v ^* color system).
Specifically, L, a, and b values were measured by an SCI (including regular reflection light) method using a spectrocolorimeter “CM-700d” manufactured by Konica Minolta. Color difference (ΔE = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^1/2 by JIS Z8730 (color display method-color difference of object color): ΔL ^* , Δa ^* , Δb ^* is The difference between the two object colors) was calculated from each L ^* a ^* b ^* measured before and after the test, and evaluated by the magnitude of the color difference. In addition, L ^* a ^* b ^* measurement before and after the test was measured at three points, and the average value was used.

<Discoloration resistance test 1: High temperature and high humidity atmosphere test>
In the discoloration resistance test for evaluating the discoloration resistance of the material, each sample was exposed to an atmosphere at a temperature of 60 ° C. and a relative humidity of 95% using a thermostatic chamber (HIFLEX FX2050, Enomoto Kasei Co., Ltd.). The test time was 24 hours, the sample was taken out after the test, the surface color of the material before and after exposure was measured with a spectrocolorimeter, L ^* a ^* b ^* was measured, and the color difference was calculated and evaluated. The smaller the color difference, the smaller the change in color tone, and thus the better the resistance to discoloration. In the corrosion resistance evaluation, the color difference values were “A”: 0 to 4.9, “B”: 5 to 9.9, and “C”: 10 or more. The color difference represents the difference between the measured values before and after the test. The larger the value, the different the color tone before and after the test. When the color difference is 10 or more, it can be confirmed that the color is sufficiently discolored, and the discoloration resistance is inferior. It can be judged.
As comparative materials, C2600 (brass: 70Cu-30Zn), C1020 (oxygen-free copper: 100Cu), and C4622 (naval brass: 63Cu-35.9Zn-1.1Sn) were similarly evaluated for discoloration resistance. The bar-shaped discoloration resistance is 50 mm for a drawn material having a diameter of 20 mm, cut perpendicularly to the longitudinal direction, and a cross section of 20 mm wide × 50 mm long is dry-surface polished using # 1200 water-resistant abrasive paper. The test was conducted. The plate-shaped material was a 10% cold-rolled material having a length of 150 mm and a width of 50 mm, and the surface of the material was subjected to surface polishing using a # 1200 water-resistant abrasive paper and subjected to a test.
C2600 and C1020 were subjected to rust prevention treatment (treatment using a commercially available rust prevention liquid for copper alloys) carried out by a general copper alloy manufacturing company. In the rust prevention treatment, the surface of each material is degreased with acetone, and then immersed in an aqueous solution containing 0.1 vol% of a commercially available rust prevention liquid for copper alloys whose main component is benzotriazole heated to 75 ° C. for 10 seconds, After washing with water and hot water, the final blower-dried material was prepared. This is similar to general copper alloy rust prevention treatment conditions (mass production). Further, C4622 and invention alloys were subjected to an exposure test without being subjected to rust prevention treatment.

<Discoloration resistance test 2: Indoor exposure test>
With the actual use as a push plate in mind, a 10% cold rolled material cut to 150mm x 50mm is pasted on the indoor door of the building in Mitsubishi Shindoh Co., Ltd. I confirmed the situation. Prior to exposure, the surface of this test material was subjected to surface polishing by dry using # 1200 water-resistant abrasive paper, and exposed at room temperature (with air conditioning) for 1 month. This push plate was used under the condition that a human hand touches at least 100 times / day (one contact time is about 1 second). The surface color of the material before and after the exposure was evaluated by measuring L ^* a ^* b ^* with a spectrocolorimeter and calculating the color difference. The evaluation criteria were the same as in the high-temperature and high-humidity atmosphere test, where the color difference values were “A”: 0 to 4.9, “B”: 5 to 9.9, and “C”: 10 or more. The C2600 rust-proofing material and the C1020 rust-proofing material were also evaluated by performing exposure tests in the same manner as comparative materials.

<Pressability>
The press punching test was carried out with a 200 kN hydraulic universal testing machine (AY-200SIII-L, manufactured by Tokyo Testing Machine Co., Ltd.) using a punching jig equipped with a punch and die having a diameter of 57 mm. The copper alloy plate was held on the upper part of the die having a circular round hole and punched from the upper part toward the lower part at a speed of 5 mm / second. The punch and die were made of SKS-3, the clearance from the punch was 3%, the die taper was 0 °, and it was carried out without lubrication. The sample to be evaluated was a 10% cold rolled material.
A sample with a width of 5 mm and a length of 10 mm was cut out from the end of a copper alloy plate punched into a circle with a diameter of 57 mm, the sample was buried in resin, and observed from a metal microscope in the vertical direction from the end of the copper alloy plate. The height of was measured. For the punched sample, the “burr height” was calculated by averaging four points divided in the 90 ° direction. The lower the “burr height”, the higher the pressability (punching), and the evaluation was based on the measured value of “burr height”. The evaluation of pressability (punching) was A: less than 5 μm, B: less than 5 to 10 μm, and C: 10 μm or more. The smaller the burr height is, the better the pressability is.

<Bendability>
The bendability was determined by bending the sample by 180 degrees as described in JIS Z 2248 (Metal Material Bending Test Method) and the condition of the bent portion. The 180-degree bending test uses a sample with a thickness of 0.9 mm that has been cold rolled 10%, cut into a length of 50 mm and a width of 10 mm parallel to the rolling direction, bent in a direction perpendicular to the rolling direction, The bending radius (R) was 0.45 mm, and 180 ° bending was performed with R / ta = 0.5 (ta is the plate thickness). Evaluation was made by visually observing the bent portion (curved portion), and A: no wrinkle or small wrinkle, B: large wrinkle, C: rough, D: cracked.
“A” (no wrinkles or small wrinkles present) that does not hinder the bending work is judged to have good bendability, and an evaluation of B or higher without cracks is desirable. If it is difficult to visually determine the size of the wrinkle, as shown in JBMA (Japan Copper and Brass Association Technical Standard) T307: 1999 copper and copper alloy sheet strip evaluation method, Part: width 10 mm) was magnified 50 times with a metallurgical microscope and observed. Further, when the material crystal grains are coarse, when bending is performed, cracks do not exist in the periphery of the bent portion, but large roughness (skin roughness) occurs, and these materials cannot be used. The evaluation of the sample that produced the roughness was “C”.

<Weldability>
Welded pipes are generally made by gradually forming plastic products in the width direction with a forming roller into a circular shape and forming them into a circular shape, then inductively generating heat with a high-frequency induction heating coil, or joining the two ends together by TIG welding. Manufactured by. The joint is heated locally, melted instantaneously, and joined at both ends, so-called pressure welding. The joint is formed with a large bead due to the excess material abutted, and the weld bead is continuous. Then, both the inside and the outside of the tube are cut and removed by the cutting blade. However, when the diameter of the welded pipe is as small as φ15 mm or less, the cutting tool to be inserted into the inside becomes too thin and a sufficient bead portion may not be cut and removed. Therefore, the bead portion is not cut and removed in all welded pipes. . The welded part has a problem in the bondability due to the adhesion of the butted part. Weldability was evaluated by a flat test described in JIS H 3320 copper and copper alloy welded tubes. A sample of about 100 mm is taken from the end of the welded tube, the sample is sandwiched between two flat plates, and is crushed until the distance between the flat plates becomes three times the wall thickness of the tube, and the welded portion of the welded tube at that time is compressed. Placed in a direction perpendicular to the direction, flat bending was performed so as to be the tip of the bending, and the state of the bent welded portion was visually observed. For flat bending, a welded pipe was used. Evaluation: A: Defects such as cracks and fine holes are not observed, B: Fine cracks are observed (the length of the opened cracks is less than 2 mm in the longitudinal direction of the pipe material), C: Partially cracked (opened cracks) Is 2 mm or more in the longitudinal direction of the pipe material).

As an evaluation of the welded portion of the welded pipe, not only the above-described flatness test but also a spread test and a 180 ° bending test were performed. The spread test was performed by the method described in JIS H 3320. In the spread test, a conical tool with a vertex angle of 60 ° is pushed into one end of a sample obtained by cutting a welded tube to 50 mm, and the outer diameter is 1.25 times (that is, the end face has a diameter of 25.4 mm. It was expanded to a position where the diameter was 31.75 mm, which was 25 times larger, and cracks in the welded portion were visually confirmed. A: Defects such as cracks and fine holes are not observed, B: Fine cracks are observed (the weld is not divided), C: Cracks are observed in the weld and are evaluated as being divided .
In the 180 ° bending test, the welded tube was cut to 300 mm, and 180 ° bending was performed using a CNC vendor machine (manufactured by Chiyoda Corporation). The welded portion was bent as a portion that becomes the outermost diameter when the 180 ° bending was performed, and the state of the welded portion was visually confirmed. In addition, the bending part (welding part) after implementing a bending process was bent and evaluated as 76.2 mm which is 3 times the diameter. The case where defects such as cracks and fine holes were not recognized was evaluated as “A”, and the case where defects such as cracks and fine holes were observed was evaluated as “C”.

As for weldability, a 25.4 mm diameter welded pipe is cut to 150 mm, both ends of the cut welded pipe are butted and a copper alloy welding rod (JIS Z 3341 YCuSi A 2.4Si-Cu added with silicon) is added. : All elements in the circumferential direction were welded by TIG welding. The pipe having a total length of 300 mm was pulled with a tensile tester (Shimadzu AG-X) until it was broken, and the tensile strength of the welded tube was measured. The cross-sectional area for obtaining the tensile strength was the cross-sectional area of the welded pipe (not the cross-sectional area of the welded portion). When the tensile strength of the butt welded pipe exceeds 70% of the tensile strength of the welded pipe (raw material) that is not butt welded, A is indicated as B, and 50-70% or higher is indicated as B, and C is indicated when the tensile strength is less than 70%. , B or more is assumed to have weldability, and A or more is assumed to have good weldability.

<Brassability>
A drawing rod having a diameter of 20 mm was cut to a length of 50 mm, a hole having a diameter of 5 mm was drilled at the center of the cut surface, and a C1100 (tough pitch copper) rod having a diameter of 4.8 mm was placed in the drill hole. The part was heated by a burner, and brazing was performed using a phosphor copper braze (JIS Z 3264 BCuP-4 7.2P-5Ag-Cu: mass% before the element symbol) to which silver was added. .
A tensile tester (Shimadzu AG-X) is used to perform a tensile test on the brazed sample. Brazing performance is good when fractured at C1100 other than the brazed part. It was evaluated. The chuck part of the tensile test (the part that holds the sample with the testing machine) is C1100 having a diameter of 20 mm and a diameter of 4.8 mm.
Each sample before brazing was degreased with acetone and brazed with no flux.

<Crystal grain size>
The grain size of the reduced 10% cold-rolled sample is a cross-section in the direction parallel to the rolling direction and a 20 mm diameter rod (reduction 9.3%) is used for the metal structure of the cross-section in the direction parallel to the drawing direction. Nikon EPIPOT 300) was observed 150 times (changed to 500 times as appropriate depending on the crystal grain size), and the α phase crystal grains of the measured metal structure were measured according to JIS H 0501 (Copper Product Grain Size Test Method). ). The crystal grain size (α phase crystal grain) was an average value of three arbitrary points.
As for the metal structure of the forged product, the area of 1/5 in the thickness direction from the forged surface was measured, and the average value of three points was obtained, as was the area ratio of the β phase and γ phase described later.

<Area ratio of β phase and γ phase>
The area ratios of the β phase and the γ phase were determined as follows. A metallographic microscope (ECLIPSE MA200 manufactured by Nikon Corp.) was used to measure the metallographic structure of the cross section in the direction parallel to the rolling direction of the 10% cold rolled sample and the cross section in the direction parallel to the drawing direction of the rod of φ20 mm drawn material (reduction 9.3%). Is observed 500 times (field of view 270 μm × 220 μm), and the observed metal structure is binarized for the β phase and the γ phase using the image processing software “WinROOF”, and the β phase with respect to the area of the entire metal structure The area ratio was defined as the area ratio. In addition, the metal structure measured 3 visual fields, and calculated the average value of each area ratio.
The weld pipe was measured at a portion 5 mm away from the outer surface in the thickness direction at a portion 5 mm away from the outer surface in the circumferential direction centering on the weld. For the forged product, a 1/5 portion in the thickness direction from the forging surface was measured. The welded pipe and the metal structure of the forged product were measured in three fields of view, and the average area ratio was calculated.

When it was difficult to discriminate the β phase or the γ phase with a 500 times magnification metal microscope, it was determined by the FE-SEM-EBSP (Electron Back Scattering Diffraction Pattern) method. That is, FE-SEM is JSM-7000F manufactured by JEOL Ltd., and TSL Solutions OIM-Ver. 5.1 was used and obtained from a phase map (Phase map) having an analysis magnification of 500 times. That is, the α phase shows the crystal structure of FCC (face centered cubic lattice), and the β phase and γ phase have the crystal structure of BCC (body centered cubic lattice). Although the β phase and the γ phase have the same crystal structure, since the interatomic distance and the lattice constant are different, the respective phases can be distinguished.

<Hot workability>
About hot workability, it evaluated by the crack condition after hot rolling. The appearance is visually observed, and those that have no damage such as cracks due to hot rolling, or those that are fine even if cracked (3 mm or less) are indicated by “A” as being excellent in practicality, and 5 mm For those where the following minor ear cracks are 5 or less over the entire length, it is indicated as “B” as practical, and for those having a large crack exceeding 5 mm or a small crack exceeding 3 mm exceeding 6 places Indicated as “C” as a practical difficulty (requires large rework in practice). In addition, when the hot deformation resistance was large and the rolling could not be performed to the specified thickness (8 mm in P1-1) by the number of passes in hot rolling, it was evaluated as difficult to be practical, and “C” was assigned. And the thing evaluated as "C" canceled the subsequent test fundamentally.

<Cold workability>
About cold workability, it evaluated by the crack condition (crack condition of a cold work material) after cold-rolling a hot-rolled material with the high processing rate of 80% or more. Appearances that have no damage such as cracks by visual inspection or those that are fine (3 mm or less) even if there are cracks are indicated by “A” as being excellent in practicality, and an ear crack exceeding 3 mm and 5 mm or less has occurred. Those with a large crack exceeding 5 mm were indicated with “C” as having difficulty in practical use. In this evaluation, cracks caused by ingots were excluded, and cracks that could be visually judged in advance by hot rolling were judged by crack lengths that occurred by cold rolling except for cracks that occurred by hot rolling. And the thing evaluated as "C" canceled the subsequent test fundamentally.

<Antimicrobial (bactericidal) 1>
The antibacterial evaluation was performed by a test method referring to (antibacterial processed product-antibacterial test method / antibacterial effect) of JIS Z 2801, and the test area (film area) and contact time were changed and evaluated. The bacterium used for the test was E. coli (strain storage number: NBRC3982), and E. coli pre-cultured at 35 ± 1 ° C. (the pre-culture method was 5.6.a method described in JIS Z 2801) was 1/500 NB. A solution in which the number of bacteria was adjusted to 1.0 × 10 ⁶ cells / mL was used as a test bacterial solution. The test method is to place a sample cut into a 20 mm square in a sterilized petri dish, drop 0.045 mL of the aforementioned test bacterial solution (E. coli: 1.0 × 10 ⁶ cells / mL), cover with a 15 mm diameter film, Close the lid. The petri dish is cultured for 10 minutes in an atmosphere of 35 ° C. ± 1 ° C. and a relative humidity of 95% (inoculation time: 10 minutes). The cultured test bacterial solution is washed out with 10 mL of SCDLP medium to obtain a washed bacterial solution. The washed bacterial solution is diluted 10-fold with phosphate buffered saline, standard agar medium is added to the bacterial solution, cultured at 35 ± 1 ° C. for 48 hours, and the number of colonies is 30 or more. In this case, the number of colonies was counted and the viable cell count (cfu / mL) was determined. Based on the number of bacteria at the time of inoculation (the number of bacteria at the start of the bactericidal test: cfu / mL), A: less than 10%, B: less than 10-33%, C: It was evaluated as 33% or more. It was judged that a sample obtained with an evaluation of A or more (that is, the number of viable bacteria in the evaluation sample is less than 1/3 with respect to the number of viable bacteria at the time of inoculation) is excellent in antibacterial properties (bactericidal properties). The reason for shortening the culture time (inoculation time) to 10 minutes is that the antibacterial (bactericidal) immediate effect was evaluated. The evaluated sample is a reduction 10% cold rolled sample. In pure copper (C1020), according to the above test method, the number of bacteria after 10 minutes is 33% of the number of inoculated bacteria. From the above, the material of evaluation A or evaluation B has the same or lower antibacterial (bactericidal) properties than pure copper (C1020), that is, the viable cell rate after 10 minutes from inoculation becomes the same or low, Excellent antibacterial (bactericidal) properties. In addition, the rod-shaped material was implemented in the cross section cut | disconnected in the vertical direction with respect to the longitudinal direction. The plate-shaped material was cut into 20 mm × 20 mm.

<Antimicrobial (bactericidal) 2>
After measuring the surface color of the above-mentioned exposed material for discoloration resistance test 2 (exposed for 1 month as a push plate for the indoor door of Mitsubishi Shindoh Co., Ltd.) A bactericidal test using a bacterial solution was performed, and antibacterial properties (bactericidal properties) of the samples after long-term use were evaluated. The test method and the evaluation method are the same as the antibacterial (bactericidal) 1 evaluation method described above.

<Corrosion resistance>
Corrosion resistance was evaluated by a dezincification corrosion test according to ISO 6509: 1981 (Corrosion of metals and alloys determination of dezincification resistance of brass). In the test, a sample maintained in a 1% cupric chloride aqueous solution heated to 75 ° C. for 24 hours was observed from the exposed surface to observe the metallographic structure in the vertical direction. Dezincification corrosion depth) was measured. The maximum dezincification corrosion depth is 200 μm or less as “A”, and the maximum dezincification corrosion depth exceeds 200 μm as “C”.

<Tensile test>
JIS Z2201: Metallic material tensile test for rolled material after heat treatment (sample before cold rolling) and 10% cold rolled sample, extruded rod and drawn rod (Re: 9.3%) Tested into No. 5 test piece (rolled material: width 25 mm, distance between marks 50 mm) and No. 4 test piece (bar material: diameter 14 mm, distance between marks 50 mm), and 200 kN hydraulic universal testing machine (stock association) Tensile tests were carried out using AY-200SIII-L) manufactured by Tokyo Test Machine. Also, the welded pipe (diameter 25.4 mm, wall thickness 1.08 mm or 1.0 mm) as welded is JIS Z2201: No. 11 test piece of metal material tensile test piece (distance between gauge points 50 mm: test piece is from pipe The core was inserted into the gripping part, and a tensile test was carried out with a 200 kN hydraulic universal testing machine (AY-200SIII-L, manufactured by Tokyo Testing Machine Co., Ltd.). Tensile strength, elongation and 0.2% yield strength were measured by a tensile test. In addition, the yield strength described in the specification indicates the yield strength when the permanent elongation is 0.2% by the offset method described in JIS Z2241: Metallic material tensile test method.
Further, when the tensile strength was σ (MPa) and the elongation was ε (%), the strength / elongation balance index M1 = σ × (1 + ε / 100) was defined as an index indicating the balance between strength and ductility.
In addition, in what implemented the manufacturing process P2, in addition to the rolling material after the heat treatment process (sample before cold rolling) and the 10% cold rolling sample, the rolling material after the heat treatment step: strip (width 111 mm × thickness) 1.0 mm) was subjected to a tensile test. The result is shown with () in the column of the tensile test result of the 10% cold rolled sample.

<Conductivity>
The conductivity was measured using SIGMATEST D2.069 (manufactured by Nippon Felster Co., Ltd.). Various rolled materials were measured at a measurement frequency of 480 kHz on the surface of a cold rolled material (Re 10%), and a bar (φ20 mm cold drawn material: Re 9.3%) was cut in a direction perpendicular to the extrusion direction.

Compositions and evaluation results are shown in Tables 1 to 10.

As a result of the test, the following was found.
A first invention alloy (a discoloration-resistant copper alloy having a composition range according to claim 1), wherein the composition index f1 is in the range of 24 ≦ f1 ≦ 40, and the composition index f2 is 1.2 ≦ f2 ≦ 4.0. In the range, the hot workability and the cold workability are also good, and the metal structure of the cold-rolled material has a β-phase ratio and a γ-phase ratio of 0.9% or less, respectively. It became 7% or less, and the average grain size became 30 μm or less. Therefore, the mechanical property (strength) is high, there is also elongation, and the strength / elongation balance index M1 is 480 or more, indicating a high numerical value. Furthermore, the discoloration resistance was good, the workability such as punchability and bendability was excellent, the antibacterial property (bactericidal property) was equal to or better than that of pure copper (C1020), and the corrosion resistance was also good.

From the viewpoint of the composition indexes f1 and f2, when these are in the preferred range, the discoloration resistance and antibacterial properties (bactericidal properties) are more excellent, and these composition indexes f1 and f2 have a great influence on each characteristic. I understood it. No. A1 and A9 in which f1 exceeds the appropriate range have many β phases and γ phases, have problems in cold workability, and are inferior in discoloration resistance and workability. On the other hand, No. f1 falls below the appropriate range. A3 and A4 could not be rolled down to a predetermined thickness because of their large deformation resistance during hot working. No. A4 had a high deformation resistance and had a problem in reduction, but Pb exceeded the proper range, a large ear crack occurred, and hot workability also had a problem.
Although the brass material (C2600) as a comparative material has good bactericidal properties, it has poor discoloration resistance and has a problem in workability such as punchability. Pure copper (C1020) was discolored in a short time and had poor discoloration resistance and low workability such as punchability. Further, as described above, the antibacterial (bactericidal) ratio of the number of viable bacteria after the test was 33% at the time of inoculation, which was the same as or worse than the first invention alloy, and the strength was weak (the value of M1 was small). . Naval brass (C4622) had a low strength / elongation balance before cold drawing and had a problem with discoloration resistance. There was also a problem with corrosion resistance (dezincification corrosion resistance).

No. Zn containing more than the range of the present invention. In A1 and A9, the composition index f1 is also larger than the range. Therefore, the ratio of β phase and γ phase in the metal structure is as large as 2% or more, and there is a problem in cold workability (large cracks are generated by cold rolling). As a result, although the strength is somewhat high, the elongation value is low, the strength / elongation balance index M1 is low, and there are significant problems in discoloration resistance, bendability and corrosion resistance, and it is a problem to use as a discoloration resistance copper alloy was there.
No. Zn content is less than the range of the present invention. In A3, the composition index f1 was also smaller than the range, the deformation resistance at the time of hot rolling became large, and it could not be rolled to a desired thickness.
The content of Sn is larger than the range of the present invention. In A2, the composition index f2 was larger than the range, and although there was no β phase in the metal structure, there were many γ phases, and thus large cracks occurred during cold rolling. For this reason, the elongation is also reduced, and M1 is also reduced, resulting in great problems in bendability and corrosion resistance. On the other hand, No. A1-1, whose Sn content is less than the range of the present invention, has a composition index f4 smaller than the range and no γ phase, but has a low tensile strength and a small M1 value. This caused problems in punching processability.
No. with more Pb content than the range of the present invention. In A4, f1 is small, but since a large crack occurred during hot rolling, the next step of cold rolling could not be performed.
On the contrary, the content of Pb is less than the range of the present invention. A6 had almost no effect on mechanical properties, discoloration resistance, and antibacterial properties (bactericidal properties), but had a high burr height when subjected to a punching test, and had a problem in press workability.
No. 1 containing more Al than the range of the present invention. In A5, the composition index f2 was also large, and the β phase ratio in the metal structure was high. Moreover, since there is much Al, the antibacterial property (bactericidal property) in the sample exposed especially for a long term deteriorated. In No. A8, in which the Al content is less than the range of the present invention, the composition indices f2 and f4 were small, the crystal grains were large, the tensile strength was small, and M1 was small. Moreover, it was inferior to discoloration resistance.

The second invention alloy (color-change resistant copper alloy having the composition range described in claim 2) is a composition in which a part of Sn and Al in the first invention alloy is replaced with Ni, and the composition index f1 is If the composition index f3 is within the range of 24 ≦ f1 ≦ 40 and 1.2 ≦ f3 ≦ 4.0, hot workability, cold workability, mechanical strength (strength / elongation balance index) In addition to good workability such as punchability, excellent bactericidal properties and corrosion resistance were obtained, and even if Sn and Al were replaced with Ni, various characteristics were at the same level, and there was no problem. In particular, when the composition index f4 is in the range of 0.02 ≦ f4 ≦ 1.8, the above-described characteristics are further improved.
No. with composition index f3 larger than 4.0. In A7, the Ni—Al-based intermetallic compound deteriorated the hot workability, resulting in a large crack.
In No. A8 in which the Si content was greater than the range of the present invention and the composition ranges f2 and f4 exceeded the range, large ear cracks occurred during hot rolling. This was because the composition indexes f2 and f4 exceeded the upper limit and the Si content increased. Although the hot workability was C evaluation, only the present alloy was subjected to various evaluations by cutting off the ears of the hot rolled material with a grinder and performing cold working. The cold workability was also evaluated as C, and a large crack occurred. There were many β-phases and γ-phases in the metal structure, so that the ductility (elongation) was small and M1 in the annealed material was small, and the bendability, antibacterial property (bactericidal property) and corrosion resistance were deteriorated.
No. in which the content of Ni exceeds the range of the present invention and the composition index f3 exceeds the range. In A11, hot workability deteriorated and large cracks occurred.

The third invention alloy (the discoloration-resistant copper alloy having the composition range described in claim 3) is the same as the first and second invention alloys described above, and further 0.01 to 1.0 mass% Si, 0.01 to 0.00. Contains one or more of 5 mass% Ti, 0.01 to 1.5 mass% Mn, 0.001 to 0.09 mass% Fe, and 0.0005 to 0.03 mass% Zr. f1 is in the range of 24 ≦ f1 ≦ 40, the composition index f2 is in the range of 1.2 ≦ f2 ≦ 4.0, or the composition index f3 is in the range of 1.2 ≦ f3 ≦ 4.0. Alloy.
In these alloys, discoloration resistance, workability, antibacterial (bactericidal) and discoloration resistance are affected by the composition index f1, f2 or f3, but are almost the same as the first invention alloy and the second invention alloy, Furthermore, the mechanical properties (strength) increased and M1 increased.

The content of Sn, Si is less than the range of the present invention, and the content of Ti is more than the range of the present invention. In A10, the elongation was small and M1 was small, and the cold workability was inferior, for example, cracking occurred in the bending workability. Moreover, since there was little Sn and Si, it resulted in inferior antibacterial property (bactericidal property).
No. in which Si, Ti and Zr are smaller than the range of the present invention. No. A3-1, and Mn and Fe are smaller than the scope of the present invention. A3-2 is No. with close composition. The mechanical properties (strength), discoloration resistance, bactericidal properties, and the like almost the same as those of No. 1 were exhibited.
On the other hand, No. Ti exceeds the scope of the present invention. In A10, cracking occurred due to bending workability, and a problem occurred in workability. Nos. In which Si, Fe, Ti, Zr and Mn exceed the scope of the present invention, respectively. A3-3, A3-4 and A3-5 have many β-phase and γ-phase and have problems with cold workability and corrosion resistance, and poor hot workability due to ingot defects due to inclusion of oxides such as Zr and Ti. , And a large amount of Mn contained, causing problems in workability and various properties such as large-scale ear cracks due to deterioration of hot workability.

The fourth invention alloy is a discoloration-resistant copper alloy of the first to third invention alloys, and further 0.005-0.09 mass% P, 0.01-0.09 mass% Sb, 0.01-0. It contains at least one of 0.09 mass% As and 0.001 to 0.03 mass% Mg. Although various characteristics are affected by the composition index f1, f2, etc., the discoloration resistance, bactericidal properties, etc. are improved as compared with the first invention alloy, and the effect of the additive element was observed. No. P, Sb, As is lower than the appropriate range of the present invention. A4-1 has a slightly different composition but a similar composition No. A4-1. Various characteristics similar to those of No. 4 were exhibited, and the effect of the additive element was not observed. On the other hand, P.Mg containing Nos. Contained beyond the proper range of the present invention. A4-2 caused problems in hot workability such as large cracks during hot working due to excessive P content and ingot defects due to Mg oxide.

The first invention alloy, the second invention alloy, and the third invention alloy were prepared by mass production trial production, and a welded pipe was made as a prototype. The soundness of the welded pipe (flatness test, spread test, 180 degree bend) The structure in the vicinity of the weld and the area ratio of β phase and γ phase were small, and there was no problem. It was also confirmed that there was no problem in weldability (butt welding). All were excellent in tensile strength and elongation, and their balance was also good. The welded pipe of the second invention alloy (No. 17 in the present figure) was manufactured by heating using a high frequency induction coil and TIG welding. Welded pipes manufactured by either method are good in the soundness of the welded pipe (flatness test, spread test, 180 ° bend), the structure is no problem with α single phase, and the tensile strength, elongation and balance between them are excellent. It was.
In addition, as a extruded material, a hot forged product was prototyped and the corrosion resistance, structure, etc. were confirmed, but there was no problem with any sample.

Thus, various invention alloys were able to obtain materials satisfying various characteristics for strip products, plate products, and welded pipes manufactured therefrom. Further, it was confirmed that the bar (extruded material) can be manufactured well, and a hot forged product can be manufactured without any problem.
If the average crystal grain size is within the range, it is affected by the composition index f1 and the like, but the mechanical properties are good, but if it is coarse, there is a problem in workability such as roughening during bending. There has occurred.

As described above, the various invention alloys contribute not only to the area ratio, discoloration resistance, and workability of the β phase and γ phase, but also to antibacterial (bactericidal) and corrosion resistance depending on the composition indices f1, f2, f3, and f4. Is within the range recited in the claims, it was confirmed that a discoloration-resistant copper alloy having various characteristics can be obtained.

According to the discoloration-resistant copper alloy of the present invention and the copper alloy member using this discoloration-resistant copper alloy, it has a yellow (brass color) color tone, hot workability, cold workability, pressability, etc. It has excellent processability and can further improve discoloration resistance, antibacterial properties, and bactericidal properties.

Claims

It contains 17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, and 0.0005 to 0.030 mass% Pb with the balance being Cu. And inevitable impurities,
Between the Zn content [Zn] mass%, the Sn content [Sn] mass%, and the Al content [Al] mass%, 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al ] ≦ 40, and 1.2 ≦ [Sn] + 2 × [Al] ≦ 4 between the Sn content [Sn] mass% and the Al content [Al] mass% .0 relationship,
The α phase matrix has a relationship of 0 ≦ 2 × (γ) + (β) ≦ 1.5 between the area ratio (γ)% of the γ phase and the area ratio (β)% of the β phase, and the α phase A discoloration-resistant copper alloy having a metal structure in which 0 to 0.7% γ phase and 0 to 0.9% β phase are dispersed in a matrix.
17 to 34 mass% Zn, 0.01 to 2.5 mass% Sn, 0.005 to 1.8 mass% Al, 0.0005 to 0.030 mass% Pb, and 0.01 to 5 mass% Containing Ni and the balance consisting of Cu and inevitable impurities,
Between the Zn content [Zn] mass%, the Sn content [Sn] mass%, the Al content [Al] mass%, and the Ni content [Ni] mass%, 24 ≦ [Zn ] + 5 × [Sn] + 3 × [Al] −0.5 × [Ni] ≦ 40, and the Sn content [Sn] mass% and the Al content [Al] mass% And Ni content [Ni] mass%, there is a relationship of 1.2 ≦ 0.7 × [Ni] + [Sn] + 2 × [Al] ≦ 4.0,
The α phase matrix has a relationship of 0 ≦ 2 × (γ) + (β) ≦ 1.5 between the area ratio (γ)% of the γ phase and the area ratio (β)% of the β phase, and the α phase A discoloration-resistant copper alloy having a metal structure in which 0 to 0.7% γ phase and 0 to 0.9% β phase are dispersed in a matrix.
Furthermore, 0.01 to 1.0 mass% Si, 0.01 to 0.5 mass% Ti, 0.01 to 1.5 mass% Mn, 0.001 to 0.09 mass% Fe, 0.0005 to Containing any one or more of 0.03 mass% Zr,
Zn content [Zn] mass%, Sn content [Sn] mass%, Al content [Al] mass%, and each content of Si, Ti, Ni, Mn, Fe and Zr Between [Si] mass%, [Ti] mass%, [Ni] mass%, [Mn] mass%, [Fe] mass% and [Zr] mass%, 24 ≦ [Zn] + 5 × [Sn] + 3 × [Al] + 2.5 × [Si] + 1.0 × [Ti] −0.5 × [Ni] + 0.5 × [Mn] + 0.2 × [Fe] + 0.1 × [Zr The discoloration-resistant copper alloy according to claim 1 or 2, which has a relationship of ≦ 40.
Further, any one of 0.005 to 0.09 mass% P, 0.01 to 0.09 mass% Sb, 0.01 to 0.09 mass% As, and 0.001 to 0.03 mass% Mg. The discoloration-resistant copper alloy according to any one of claims 1 to 3, comprising at least one kind.
The discoloration-resistant copper alloy according to any one of claims 1 to 4, which is used in the form of a welded pipe, a forged product, or a casting.
The discoloration-resistant copper alloy according to any one of claims 1 to 5, wherein a viable cell rate after 10 minutes in the antibacterial test is equal to or lower than a viable cell rate of pure copper.
A copper alloy member configured by joining a base material made of the discoloration-resistant copper alloy according to any one of claims 1 to 6 and another member.
Door handle, door knob, door push plate, handrail, bed rail, side board, desk top, chair back, skirt handle member, pen grip, keyboard, mouse, sink, strap, switch, switch cover, building material The copper alloy member according to claim 7 used as the above.