JP2016183381A - Copper alloy bar and copper alloy member - Google Patents

Abstract

A copper alloy rod having a yellow to silver white color tone, excellent workability and mechanical properties, and excellent in both discoloration resistance and antibacterial properties (bactericidal properties), and hot forging comprising the copper alloy rod Provided is a copper alloy member using the material. SOLUTION: 30.0 to 42.0 mass% Zn, 0.0005 to 0.30 mass% Pb, 0.01 to 11.0 mass% Ni, and 0.01 to 1.5 mass% Sn. Furthermore, 0.01-1.2 mass% Al, 0.01-1.2 mass% Mn, 0.005-0.07 mass% As, 0.005-0.07 mass% P A copper alloy rod containing at least one of 0.005 to 0.07 mass% of Sb, the balance being Cu and inevitable impurities, 33.0 ≦ f1 ≦ 38.0, 3.3 ≦ f2 ≦ 4.8, 1.5 ≦ (β) + (γ) ≦ 14.0, and the number density of β phases is 9 to 29 / mm. [Selection figure] None

Description

  The present invention relates to a copper alloy rod having discoloration resistance and a copper alloy member composed of a hot forging made of the copper alloy rod. In particular, a copper alloy rod excellent in hot extrudability, hot forgeability, machinability and mechanical properties, and excellent in discoloration resistance, antibacterial properties and bactericidal properties, and a hot forging material comprising this copper alloy rod The present invention relates to a copper alloy member using.

  Conventionally, in order to prevent the influence of the surface oxidation of copper alloys such as Cu-Zn, the copper alloy products are subjected to plating treatment such as nickel / chrome plating, or the surface is coated with a resin such as clear coating. Yes. However, the plating product has a problem that the plating layer on the surface peels off after long-term use.

  Copper alloys such as Cu-Zn have a brass color when the Zn content exceeds 15 mass% or 20 mass%, but they do not form a protective coating such as plating or painting, and are decorated on the surface of the material. If used for goods, it will be affected by the environment in which it is placed, but it will turn brown or reddish brown in a short period of time.

  In addition, when normal copper alloy (copper alloy without plating or surface coating) is actually used for the handle, lever handle, door handle, handrail, etc., the material that is in contact with the human body over time and the portion that is not A color difference 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.

  Furthermore, it is known that a copper alloy has an antibacterial action (bactericidal action). By using an antibacterial (bactericidal) copper alloy for a member that can be contacted by an unspecified number of people, it is possible to prevent infection by various bacteria and viruses.

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 alloys.
As such a Cu—Ni—Zn alloy, for example, JIS C 7541 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 Mn (0.1 to 0.5 mass%) in addition to Al (5 to 9 mass%), Ni (1 to 4 mass%), and In (0.005 to 0.3 mass%). , Co (0.001-0.01 mass%), Be (0.0025-0.2 mass%), Ti (0.001-0.01 mass%), Cr (0.05-0.2 mass%), Si (0.001 to 0.5 mass%), Zn (0.005 to 0.5 mass%), Sn (0.003 to 0.4 mass%) one or two of them, the remainder Cu and inevitable impurities An aluminum copper alloy is disclosed.

  However, since the copper alloy disclosed in JIS C 7541 contains a large amount of Ni and Pb and has problems in health and hygiene, its use is limited. Ni is a cause of strong Ni allergy among metal allergies, and Pb is a harmful substance as is well known, so it can be used as building hardware such as handrails that directly touch human skin, and personal items such as home appliances. There is a problem with its use. 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 copper alloy containing 5 mass% or more of Al, which is excellent in discoloration resistance but poor in workability such as rollability. Manufactured as. Therefore, it is difficult to process into a thin plate or the like. Furthermore, this copper alloy has poor cold workability, such as cracking at the bent portion because the ductility is poor in processing involving bending, for example, 90 ° bending. In addition, since an aluminum oxide film is formed on the surface, the antibacterial property is weak, and the antibacterial property is impaired due to long-term use.

  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). is there. As described above, the copper alloy becomes a material having various colors depending on the additive element. However, when used under the condition in contact with the human body as described above, it is difficult to avoid discoloration although it varies depending on the alloy. On the other hand, when the surface is coated (painted) with a resin film such as a clear coat in order to prevent discoloration, the above-described antibacterial (bactericidal) function is not exhibited.

  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. This reaction is the same as so-called corrosion, and when antibacterial properties (bactericidal properties) are exerted, a corrosion reaction occurs on the surface. The corrosion of the surface of the copper alloy causes 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.

  As a copper alloy having both antibacterial properties and discoloration resistance, Patent Document 2 discloses 51.0-58.0 mass% Cu, 9.0-12.5 mass% Ni, and 0.0003-0. 0.010 mass% C and 0.0005 to 0.030 mass% Pb, the balance being Zn and inevitable impurities, Cu content [Cu] mass%, and Ni content [Ni] mass % And the relationship of 65.5 ≦ [Cu] + 1.2 × [Ni] ≦ 70.0, and the β phase of 0 to 0.9% in terms of area ratio is dispersed in the α phase matrix. A silver-white copper alloy characterized by a metal structure is disclosed.

JP 2004-143574 A Japanese Patent No. 524,015

  However, the anti-discoloration copper alloy disclosed in Patent Document 2 has high hot deformation resistance, and in order to perform hot extrusion in a mass-production extrusion facility, it must be extruded at a temperature just below the melting point. If it is done, the material melts and temperature control is very difficult. Even if the temperature can be controlled and the extrusion can be performed, the general mass production equipment having an extrusion press capacity of about 3000 tons cannot be fully pressed, and the yield is very poor. Similarly, the hot forgeability is poor, and it is very difficult to control the temperature during forging as during hot extrusion. Even if heated properly, the original hot deformation resistance is very high, so a general forging facility with a press capacity of about 500 tons must be forged multiple times to form the desired shape. However, there is a problem that the cost becomes high. Moreover, since the discoloration-resistant copper alloy disclosed in Patent Document 2 is mainly used for plate and strip products, it hardly requires machinability. And this copper alloy matrix is almost composed of α phase, and β phase area ratio is 0-0.9%, so machinability is low and it is improved as a member requiring machinability. There is room for.

  The present invention was made against the background as described above, and has a yellow (brass color) to silver-white color tone, as well as hot extrudability, hot forgeability, machinability, and mechanical properties. It is an object of the present invention to provide a copper alloy rod excellent in both discoloration resistance and antibacterial properties (bactericidal properties), and a copper alloy member using a hot forging made of the copper alloy rod.

The present invention has been completed based on the knowledge of the present inventors. That is, the following invention is provided in order to solve the said subject.
The copper alloy rod according to the first aspect of the present invention includes 30.0 to 42.0 mass% Zn, 0.0005 to 0.30 mass% Pb, 0.01 to 11.0 mass% Ni, 0.01 to 1.5 mass% Sn, and 0.01 to 1.2 mass% Al, 0.01 to 1.2 mass% Mn, 0.005 to 0.07 mass% As, It is a copper alloy rod containing any one or more of 0.005 to 0.07 mass% P and 0.005 to 0.07 mass% Sb, with the balance being Cu and inevitable impurities, and containing Zn [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al] mass% And Mn content [Mn] mas %, As content [As] mass%, P content [P] mass%, and Sb content [Sb] mass%, 33.0 ≦ [Zn] −0.5 * [Pb] + 3.6 * [Sn] -0.4 * [Ni] + 2.4 * [Al] -0.5 * [Mn] + 0.5 * [As] + 2.0 * [P] +2. 5 × [Sb] ≦ 38.0 and 3.3 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] +1.8 X [Al] ≦ 4.8 The relationship is 1.5 ≦ (β) between the β phase area ratio (β)% and the γ phase area ratio (γ)% in the α phase matrix. It has a relationship of + (γ) ≦ 14.0, and has a metal structure in which the number density of β phases crossing a straight line in a direction perpendicular to the longitudinal direction of β phases in an arbitrary cross section is 9 to 29 pieces / mm .

  The copper alloy rod according to the second aspect of the present invention includes 33.0 to 38.0 mass% Zn, 0.0005 to 0.30 mass% Pb, 1.5 to 4.0 mass% Ni, 0.1 to 1.2 mass% Sn, and 0.01 to 0.5 mass% Al, 0.01 to 0.5 mass% Mn, 0.005 to 0.07 mass% As, It is a copper alloy rod containing any one or more of 0.005 to 0.07 mass% P and 0.005 to 0.07 mass% Sb, with the balance being Cu and inevitable impurities, and containing Zn [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al] mass% And Mn content [Mn] mass% Between the As content [As] mass%, the P content [P] mass%, and the Sb content [Sb] mass%, 34.0 ≦ [Zn] −0.5 × [Pb ] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] + 0.5 × [As] + 2.0 × [P] + 2.5 × [ Sb] ≦ 38.0, and 3.6 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] + 1.8 × [Al ] ≦ 4.5, and 1.5 ≦ (β) + (γ between the area ratio (β)% of the β phase and the area ratio (γ)% of the γ phase in the α phase matrix. ) ≦ 14.0 and a metal structure in which the number density of β phases crossing a straight line in a direction perpendicular to the longitudinal direction of the β phase in an arbitrary cross section is 9 to 29 pieces / mm.

  The copper alloy member according to the third aspect of the present invention is composed of a hot forging material formed by hot forging the copper alloy rods according to the first and second aspects described above or a combination of the hot forging materials. The

  The copper alloy member according to the fourth aspect of the present invention is the copper alloy member according to the third aspect described above, including a handrail, a door knob, a door handle, a lever handle, a pole, a desk, a chair, a shelf, a member of a nurskirt handle, Bedside rails, grips, writing instruments, carriages, carts, food carts, carts, desk and chair components, key materials, medical equipment components, valve handles, indoor electrical switches, mechanical buttons, Western food Used as a container and musical instrument.

  According to the present invention, it has a yellow (brass color) to silver-white color tone, is excellent in hot extrudability, hot forgeability, machinability, and mechanical properties, and further has discoloration resistance and antibacterial properties (bactericidal properties). It is possible to provide an excellent copper alloy rod and a copper alloy member made of this copper alloy rod.

In the Example of this invention, it is the side view which showed typically the shape of the grip manufactured by the manufacturing process P4.

  Below, the 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, the composition index f1 and f2 are prescribed | regulated as follows using this content display method.

Composition index f1 = [Zn] −0.5 × [Pb] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] + 0.5 × [ As] + 2.0 × [P] + 2.5 × [Sb]
Composition index f2 = 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] + 1.8 × [Al]

The copper alloy rod according to the first embodiment of the present invention includes 30.0 to 42.0 mass% Zn, 0.0005 to 0.30 mass% Pb, and 0.01 to 11.0 mass% Ni. 0.01 to 1.5 mass% Sn, 0.01 to 1.2 mass% Al, 0.01 to 1.2 mass% Mn, 0.005 to 0.07 mass% As A copper alloy rod containing 0.005 to 0.07 mass% P or 0.005 to 0.07 mass% Sb, with the balance being Cu and inevitable impurities, Content [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al] mass % And Mn content [Mn] m 33.0 ≦ [Zn] −. 0 between the ss%, the As content [As] mass%, the P content [P] mass%, and the Sb content [Sb] mass%. 5 * [Pb] + 3.6 * [Sn] -0.4 * [Ni] + 2.4 * [Al] -0.5 * [Mn] + 0.5 * [As] + 2.0 * [P] +2 0.5 × [Sb] ≦ 38.0, and 3.3 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] +1. 8 × [Al] ≦ 4.8. That is, in the copper alloy rod according to the first embodiment, the composition index f1 is in the range of 33.0 ≦ f1 ≦ 38.0, and the composition index f2 is in the range of 3.3 ≦ f2 ≦ 4.8. Is done.
The copper alloy rod according to the first embodiment having the above composition is referred to as a first invention alloy rod.

The copper alloy rod according to the second embodiment of the present invention includes 33.0 to 38.0 mass% Zn, 0.0005 to 0.30 mass% Pb, and 1.5 to 4.0 mass% Ni. 0.1 to 1.2 mass% Sn, 0.01 to 0.5 mass% Al, 0.01 to 0.5 mass% Mn, 0.005 to 0.07 mass% As A copper alloy rod containing 0.005 to 0.07 mass% P or 0.005 to 0.07 mass% Sb, with the balance being Cu and inevitable impurities, Content [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al] mass % And Mn content [Mn] mass 34.0 ≦ [Zn] −0.5 × between the As content [As] mass%, the P content [P] mass%, and the Sb content [Sb] mass%. [Pb] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] + 0.5 × [As] + 2.0 × [P] +2.5 × [Sb] ≦ 38.0 and 3.6 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] + 1.8 × [Al] ≦ 4.5. That is, in the copper alloy rod according to the second embodiment, the composition index f1 is in the range of 34.0 ≦ f1 ≦ 38.0, and the composition index f2 is in the range of 3.6 ≦ f2 ≦ 4.5. Is done.
The copper alloy rod according to the second embodiment having the above composition is referred to as a second invention alloy rod.

  The copper alloys (first and second invention alloy rods) according to the first and second embodiments of the present invention described above have the β phase area ratio (β)% and the γ phase area ratio (γ) in the α phase matrix. )% And the number density of β phases crossing on a straight line in a direction perpendicular to the longitudinal direction of the β phase in an arbitrary cross section, with a relationship of 1.5 ≦ (β) + (γ) ≦ 14.0 Has a metal structure of 9 to 29 pieces / mm.

The reason why the component composition, composition index f1, f2, and metal structure are defined as described above will be described below.
First, the contents of Zn, Pb, Ni, and Sn, which are essential elements of the copper alloy rod of the present invention (first and second invention alloy rods), will be described.

(Zn: 30.0 mass% or more and 42.0 mass% or less)
Zn, in the copper alloy rod of the present invention, by co-addition with Sn and Ni, the color tone is changed from a brass color to a slightly yellowish silver-white color, and discoloration resistance and antibacterial properties (bactericidal properties) are improved. It is an important element that improves mechanical strength such as tensile strength and proof stress. By containing Zn in an amount of 30.0 mass% or more, more preferably 33.0 mass% or more, the above-described effects can be obtained. On the other hand, even if Zn is contained in excess of 42.0 mass%, an effect commensurate with the content cannot be obtained, and β-phase is more likely to remain, and although the strength is improved, cold workability, impact resistance, Corrosion resistance and antibacterial properties (bactericidal properties) will decrease. Therefore, the Zn content is 42.0 mass% or less, preferably 38.0 mass% or less. Thus, the Zn content is in the range of 30.0 mass% or more and 42.0 mass% or less, and particularly when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the Zn content is 33. It is preferable to set it to 0.0 mass% or more and 38.0 mass% or less.

(Pb: 0.0005 mass% or more and 0.30 mass% or less)
Pb is an element having an effect of improving workability and machinability in shearing and polishing in the copper alloy rod of the present invention. Here, although the above-mentioned effect can be obtained by containing Pb in an amount of 0.0005 mass% or more, hot workability is deteriorated if the content exceeds 0.30 mass%. Moreover, since Pb is a harmful substance, it is desirable to keep the content to a minimum. Therefore, the Pb content is in the range of 0.0005 mass% to 0.30 mass%, preferably 0.005 mass% to 0.1 mass%.

(Ni: 0.01 mass% or more and 11.0 mass% or less)
Ni is an important element in securing discoloration resistance and mechanical strength in the copper alloy rod of the present invention, and the above effect is exhibited at a content of at least 0.01 mass%. On the other hand, even if Ni is contained in excess of 11.0 mass%, the above effect is saturated although the discoloration resistance is slightly improved in view of the relationship with other elements. On the other hand, hot extrudability, hot forging The antibacterial properties and color tone are impaired. Moreover, if Ni is excessive, it can also cause allergies (Ni allergy). Therefore, when adding Ni, the Ni content should be in the range of 0.01 mass% or more and 11.0 mass% or less to ensure even higher antibacterial properties (bactericidal properties) without particularly impairing discoloration resistance. In order to achieve this, it is preferably 1.0 mass% or more and 5.0 mass% or less, and most preferably 1.5 mass% or more and 4.0 mass% or less.

(Sn: 0.01 mass% or more and 1.5 mass% or less)
Sn is an element having an effect of improving discoloration resistance and mechanical strength in the copper alloy rod of the present invention. Here, the above-mentioned operation and effect can be obtained by containing 0.01 mass% or more of Sn. On the other hand, if Sn is contained in excess of 1.5 mass%, an effect commensurate with the content cannot be obtained, and the solidus temperature and the liquidus temperature are widened during casting, which tends to cause concentration segregation, and hot working. And cold workability will deteriorate. In addition, the amount of γ phase increases, and the antibacterial and corrosion resistance also decreases. Therefore, when Sn is added, the Sn content is set within a range of 0.01 mass% to 1.5 mass%. In particular, when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the Sn content is preferably 0.1 mass% or more, and optimally 0.2 mass% or more. The upper limit of the content is preferably 1.2 mass%, and most preferably 1.0 mass%. In particular, when the value of 0.7 × [Ni] + [Sn] is 1.2 or more and 3.5 or less, excellent discoloration resistance and antibacterial properties can be provided.

  Next, Al, Mn, As, P, and Sb, which are essential elements for selection, will be described.

(Al: 0.01 mass% or more and 1.2 mass% or less)
Al is an element that has the effect of improving the flowability (castability), discoloration resistance, and strength during casting in the above-described copper alloy. Here, the above-mentioned effect can be obtained by containing Al by 0.01 mass% or more. On the other hand, even if Al is contained exceeding 1.2 mass%, an effect commensurate with the content cannot be obtained, and a strong oxide film is formed, so that antibacterial properties (bactericidal properties) are inhibited. Therefore, when Al is added, the Al content is set within a range of 0.01 mass% to 1.2 mass%. In addition, by co-adding Al with Sn, good discoloration resistance can be obtained without reducing antibacterial properties (bactericidal properties). The content of Al is preferably 0.1 mass% or more and 1.1 mass% or less, and optimally 0.9 mass% or less. Also, when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the upper limit of the Al content is preferably 0.5 mass% or less from the viewpoint of the interaction between Ni and Al. Is 0.3 mass% or less.

(Mn: 0.01 mass% or more and 1.2 mass% or less)
Mn is an element that exerts an effect by co-addition with Ni on the color tone surface of the copper alloy rod described above, enhances whiteness, and improves discoloration resistance, and plays a role as a Ni substitute element. The addition of Mn also has the effect of improving strength, wear resistance, and bending workability. Here, the above-described effects can be obtained by containing Mn in an amount of 0.01 mass% or more. On the other hand, when the content of Mn exceeds 1.2 mass%, an effect commensurate with the content cannot be obtained, hot workability is lowered, and antibacterial properties (bactericidal properties) are lowered. Therefore, when Mn is added, the Mn content is in the range of 0.01 mass% to 1.2 mass%, preferably 0.1 mass% to 0.9 mass%. In particular, the upper limit when the Ni content is 1.5 mass% or more and 4.0 mass% or less is preferably 0.5 mass% or less, and optimally 0.3 mass% or less.

(As: 0.005 mass% or more and 0.07 mass% or less)
As is an element having an effect of improving the corrosion resistance of the α-phase matrix in the above-described copper alloy rod. Here, the above-described effects can be obtained by containing As in an amount of 0.005 mass% or more. On the other hand, when the content of As exceeds 0.07 mass%, not only an effect commensurate with the content cannot be obtained, but also As is a harmful substance, it is desirable to keep the content to a minimum. Therefore, when As is added, the content of As is set in the range of 0.005 mass% to 0.07 mass%. In addition, since As is highly toxic, it is preferably 0.05% by mass or less.

(P: 0.005 mass% or more and 0.07 mass% or less)
P, like As, is an element that has the effect of improving the corrosion resistance of the α-phase matrix in the copper alloy rod described above, and has the effect of improving the hot water flowability (castability) during casting. Here, the above-mentioned effect can be obtained by containing 0.005 mass% or more of P. On the other hand, if the P content exceeds 0.07 mass%, an effect commensurate with the content cannot be obtained, and the hot workability and the cold workability during the production of the material are adversely affected. Therefore, when P is added, the P content is within the range of 0.005 mass% to 0.07 mass%, and more preferably 0.01 mass% to 0.04 mass%.

(Sb: 0.005 mass% or more and 0.07 mass% or less)
Similarly to P, Sb is an element having an effect of improving the corrosion resistance of the α-phase matrix in the above-described copper alloy rod. Here, the above-described effects can be obtained by containing Sb in an amount of 0.005 mass% or more. On the other hand, if the Sb content exceeds 0.07 mass%, not only an effect commensurate with the content cannot be obtained, but also Sb is a harmful substance, so it is desirable to keep the content to a minimum. Therefore, when Sb is added, the Sb content is set in the range of 0.005 mass% to 0.07 mass%. In addition, since Sb has strong toxicity, it is preferable to set it as 0.05 mass% or less.

(Cu: remainder)
Cu is a residual component of the above-described elements (except for 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, content of Cu for exhibiting various characteristics is 48.0 mass% or more and 69.0 mass% or less, Preferably it is 49.0 mass% or more and 68.0 mass% or less. In particular, when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the optimum content is 58.0 mass% or more and 64.0 mass% or less.

(Inevitable impurities)
Inevitable impurities include Fe, Co, Cr, Ag, Ca, Sr, Ba, Sc, Y, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, Se, Te, Rh, Examples include Ir, Pd, Pt, Au, Cd, Ga, In, Li, Ge, Tl, Bi, S, O, C, Be, N, H, Hg, B, and rare earth. These inevitable impurities are desirably 0.5 mass% or less in total.

  Next, the composition index and metal structure of the copper alloy rod of the present invention will be described.

(Composition index f1)
Here, in order to simultaneously satisfy various characteristics such as hot workability, machinability, discoloration resistance, antibacterial property (bactericidal property) in the copper alloy rod of the present invention, the composition index f1 = [Zn] − 0.5 × [Pb] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] + 0.5 × [As] + 2.0 × [P ] + 2.5 × [Sb] is important to satisfy the relational expression of 33.0 ≦ f1 ≦ 38.0. In the above formula, for Ni, Sn, Al, and Mn, when the respective contents are less than 0.01 mass%, the influence on the characteristics is small, and thus [Ni], [Sn], [ The calculation is performed assuming that the values of [Al] and [Mn] are 0. As, As, P, and Sb are less than 0.005 mass%, since the effect on the characteristics is small. Therefore, the values of [As], [P], and [Sb] are calculated as 0, respectively. To do. Moreover, about the Pb, when the content is less than 0.0005 mass%, since it has little influence on a characteristic, the value of [Pb] is calculated as 0. Further, for elements not added, the content is calculated as 0. As for the impurities inevitably contained, the composition index f1 and its relational expression are hardly affected when the total impurity amount is less than 0.5 mass%. When the total amount of inevitable impurities exceeds 0.5 mass%, the following preferable range may be satisfied.

  In the relational expression of f1 (33.0 ≦ f1 ≦ 38.0), when f1 is less than the lower limit of 33.0, hot workability, machinability, strength, and discoloration resistance are deteriorated or decreased. If the upper limit of 38.0 is exceeded, the corrosion resistance and antibacterial properties will deteriorate or decrease. In the composition index f1, Zn is a value serving as a base for the composition index f1, and particularly affects hot workability, strength, discoloration resistance, and antibacterial properties. Since Sn particularly affects the formation of β phase and γ phase and contributes to improvement of strength and antibacterial properties (bactericidal properties), a positive coefficient is given. Al has an effect similar to Sn, but its influence is a little smaller than Sn, and gives a coefficient that is comprehensively taken into consideration including the effect of discoloration resistance. Contrary to Sn, Ni and Mn are mainly evaluated to inhibit the formation of the β phase, and are given a negative coefficient in consideration of corrosion resistance and discoloration resistance. By satisfying the relational expression f1 above, it is possible to simultaneously satisfy hot workability, machinability, strength, discoloration resistance, and antibacterial properties (bactericidal properties). Note that the value of the composition index f1 is preferably 33.5 or more, and more preferably 34.0 or more. Particularly when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the optimum value is 35.0 or more, and the upper limit is 37.5. Thus, by setting not only the component range of each element but also the value of the composition index f1 within a narrow range, the problem of the present invention can be solved.

(Composition index f2)
Furthermore, in order to have the opposite characteristics of discoloration resistance and antibacterial properties (bactericidal properties) at the same time in the above-mentioned copper alloy rod, in addition to satisfying the above relational expression, the composition index f1 satisfies Zn, Ni It is very important to adjust the balance of the contents of Sn and Al. That is, the composition index f2 = 0.05 × [Zn] + 3.0 × exp (−1 / [Ni]) + 0.7 × [Sn] + 1.8 × [Al] is 3.3 ≦ f2 ≦ 4. 8 needs to be satisfied. In this composition index f2, for Ni, Sn, and Al, when each content is less than 0.01 mass%, the influence on the characteristics is small, so exp (−1 / [Ni]), [ The calculation is performed assuming that the values of Sn] and [Al] are 0. When the composition index f2 is less than 3.3, there is a problem in the discoloration resistance. When the f2 exceeds 4.8, the discoloration resistance is improved, but the antibacterial property (bactericidal property) is impaired.

  In the relational expression of f2 (3.3 ≦ f2 ≦ 4.8), Zn increases discoloration resistance and antibacterial properties (bactericidal properties) by co-addition with Sn and Ni, and has tensile strength, yield strength, etc. Although mechanical strength is improved, the effect commensurate with the content is significantly less than other elements. Therefore, a considerably small coefficient is given to Zn. Al exhibits a great effect on the color fastness, and particularly when Al is added together with Sn, the color fastness is particularly remarkably improved. Therefore, a large coefficient is given in consideration of strength and other characteristics. On the other hand, the composition index f2 indicates that antibacterial properties (bactericidal properties) are impaired when the Al content is excessively increased. Sn also shows a tendency similar to that of Al, but the coefficient of discoloration resistance and the like is small because its effect is smaller than that of Al. Ni exerts an effect mainly on the color fastness, but a certain amount is necessary to exert the effect, and the effect is rapidly increased particularly when the addition amount is in the range of 1.0 to 5.0 mass%. However, after 5.0 mass%, the effect increases slightly, but the effect increases to 11.0 mass%, and if it exceeds 11.0 mass%, the anti-bacterial property decreases rather than the effect of discoloration resistance is almost saturated. This has been confirmed by experiments. That is, since the effect of Ni exhibits an exponential behavior as described above, the composition index f2 approximates the effect of Ni by expressing the term [Ni] as an exponential function with an appropriate coefficient. Yes. By satisfying such a relational expression of the composition index f2, it is possible to achieve both contradictory properties of discoloration resistance and antibacterial properties (bactericidal properties). The value of the composition index f2 is optimally 3.6 or more and 4.5 or less. In particular, when the Ni content is 1.5 mass% or more and 4.0 mass% or less, the value of f2 is optimally 3.6 or more and 4.5 or less.

(Importance of relational expressions of composition indexes f1 and f2)
The copper alloy rod of the present invention is a brass alloy composed of Zn and Cu having a base of 30.0 to 42.0 mass%, but is far superior to the base brass in color change resistance and at least equal to or more than brass. This is a copper alloy rod having antibacterial properties (bactericidal properties). Moreover, even when long-term use is assumed, it is an alloy bar that maintains its antibacterial properties without deteriorating.

  As represented by pure copper, copper has excellent antibacterial properties, but is inferior in discoloration resistance. From a general concept, it seems that discoloration resistance and antibacterial properties are contradictory properties. In order to achieve both discoloration resistance and antibacterial properties, it is not sufficient to simply add Ni, Sn, Al or other elements to brass, and the interaction of Zn, Ni, Sn, and Al The relational expression of the composition index f2 in consideration is very important. Furthermore, in addition to satisfying the relational expression of f2 to achieve both discoloration resistance and antibacterial properties, a copper alloy bar having hot workability, machinability, corrosion resistance, and mechanical properties (mechanical strength) is obtained. For this purpose, not only the relational expression of the composition index f2 but also the relational expression of the composition index f1 must be satisfied at the same time. In other words, in copper alloys, all these properties (discoloration resistance, antibacterial properties, hot workability, machinability, corrosion resistance, and mechanical properties) should be provided at the same time simply by specifying the range of each component content. The content of each component must be within the scope of the present invention, and the components must satisfy all the relational expressions of the composition indexes f1 and f2. Therefore, when the content of each component is such that f1 and f2 are outside the range of the above relational expression, the content of Zn, Ni, Sn, Al, or other elements is within the scope of the present invention. However, discoloration resistance, antibacterial properties, hot workability, machinability, corrosion resistance and mechanical properties cannot be combined at the same time.

(Metal structure)
If a hard and brittle β phase or γ phase is present in excess of a predetermined amount in the α phase matrix, the corrosion resistance and discoloration resistance are adversely affected. 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. The γ phase is generated when the β phase that appears at high temperature is transformed into an α phase and a γ phase by a eutectoid reaction.

  In a copper alloy rod, the β phase is usually present so that the longitudinal direction of the β phase is parallel to the extrusion direction. Therefore, since cutting is usually performed when a hot-extrusion rod is machined, not only the ratio of the β phase in the α phase matrix but also the number density in the direction perpendicular to the longitudinal direction of the β phase Important in gender. Furthermore, the number density of the β phase is important because it also affects the resistance to discoloration and corrosion.

  If the sum of the area ratio (β)% of β phase and the area ratio (γ)% of γ phase is less than 1.5%, the total amount of β phase and γ phase is too small, so machinability and hot working The nature is low. If the sum of the area ratio (β)% of the β phase and the area ratio (γ)% of the γ phase is more than 14.0%, the total amount of the β phase and the γ phase is too large. Although machinability is improved, cold workability, corrosion resistance, and discoloration resistance are reduced. Therefore, the sum of the β phase area ratio (β)% and the γ phase area ratio (γ)% in the α phase matrix is in the range of 1.5% to 14.0%, preferably 2.5%. % To 14.0%. The area ratio of the β phase is preferably 1.5% or more. Thereby, excellent hot workability and machinability are obtained. Here, in order to combine machinability, corrosion resistance, and discoloration resistance at the same time, not only is the sum of the β phase area ratio (β)% and the γ phase area ratio (γ)% limited to the above range, Furthermore, it is necessary that the number density of β phases in a direction perpendicular to the longitudinal direction of the β phase is within a predetermined range. When the number density of β phases is less than 9 / mm, even if the sum of the β phase area ratio (β)% and the γ phase area ratio (γ)% is within the appropriate range, the machinability is poor. When the β phase exceeds 29 pieces / mm, the machinability is improved, while the sum of the β phase area ratio (β)% and the γ phase area ratio (γ)% is within an appropriate range. Corrosion resistance and discoloration resistance are reduced. Accordingly, the number density of β phases in the direction perpendicular to the longitudinal direction of the β phases is in the range of 9 / mm to 29 / mm, preferably 10 / mm to 28 / mm.

  In the case of hot forgings, the cutting direction at the time of cutting depends on the shape of the product, so the cutting direction cannot be specified, but the presence form of the β phase of the hot forging is usually the direction that undergoes hot forging It becomes a form that extends in the vertical direction. Therefore, when cutting is performed in a direction perpendicular to the longitudinal direction of the β phase, the number density in the direction perpendicular to the longitudinal direction of the β phase is important in machinability even for a forged material.

  As described above, the copper alloy rods according to the first and second embodiments of the present invention have excellent discoloration resistance, antibacterial properties, hot workability (hot extrudability, hot forgeability), and machinability. With corrosion resistance and mechanical properties. Therefore, these copper alloy rods are suitable for forming by hot forging, and are suitable for a copper alloy member composed of a hot forged material formed by hot forging the copper alloy rod or a combination thereof. More specifically, handrails, door knobs, door handles, lever handles, poles, desks, chairs, shelves, nur skirt handle members, bedside rails, grips, writing instruments, companion vehicles, carts, food transport carts, carts, etc. It is suitable for components for desks and chairs, keys, members for medical instruments, valve handles, indoor electrical switches, buttons for mechanical devices, Western dishes, and copper alloy members used as musical instruments.

  Although the embodiment of the present invention has been described above, the present invention is not limited to this, and can be appropriately changed without departing from the technical idea of the present invention.

  Hereinafter, the result of the confirmation experiment conducted to confirm the effect of the present invention will be shown. In addition, the following Examples are for demonstrating the effect of this invention, Comprising: The structure, process, and conditions which were described in the Example do not limit the technical scope of this invention.

  Copper alloy (alloy Nos. 1 to 22) having the composition, composition index, and metal structure of the above-described first invention alloy bar and second invention alloy bar, and copper having a composition, composition index, and metal structure for comparison Using alloys (alloys Nos. A1 to A16, B1 to B3), copper alloy rods as samples were produced by changing the manufacturing process. The composition of each copper alloy is shown in Tables 1 and 2. In addition, as a copper alloy for comparison, C2600, C2800 defined in JIS H 3250 and alloys described in Patent Document 2 were used (Alloy Nos. B1 to B3).

(Manufacturing process P1)
Raw materials adjusted to the predetermined components shown in Tables 1 and 2 were melted in a groove-type low-frequency induction heating furnace to produce a bar-shaped ingot having a diameter of 240 mm and a length of 700 mm, and the ingot was subjected to a predetermined temperature T1 (° C. ) And a round bar extruded material having a diameter of 22.5 mm was produced by a 3000 ton extruder. In addition, the cooling after extrusion was performed by air cooling.

(Manufacturing process P2)
Raw materials adjusted to the predetermined components shown in Tables 1 and 2 were melted in a groove-type low-frequency induction heating furnace to produce a bar-shaped ingot having a diameter of 240 mm and a length of 700 mm, and the ingot was subjected to a predetermined temperature T1 (° C. ), And a bus bar shaped extruded material of 6.5 mm × 30 mm (R = 1) was produced by a 3000 ton extruder. In addition, the cooling after extrusion was performed by air cooling.

(Manufacturing process P3)
The round bar with a diameter of 22.5 mm produced by the manufacturing process P1 was cut into a length of 50 mm, heated to a predetermined temperature T2 (° C.) in a furnace, and flat forged into a shape of 50 mm × 50 mm × 8 mm thickness. The cooling after forging was performed by air cooling.

(Manufacturing process P4)
The round bar with a diameter of 22.5 mm produced by the manufacturing process P1 was cut into a length of 240 mm, heated in a furnace to a predetermined temperature T2 (° C.), and hot forged into the shape of the grip shown in FIG. The cooling after forging was performed by air cooling. 1 shows the side surface of the grip when viewed on the XY plane orthogonal to each other (on the surface orthogonal to the grip mounting surface) when the horizontal direction in FIG. 1 is the X direction and the vertical direction is the Y direction. FIG.

(Predetermined temperatures T1, T2)
Table 1 shows the temperature T1 immediately before the hot extrusion and the temperature T2 immediately before the hot forging for the predetermined temperatures T1 and T2 in the manufacturing steps P1 to P4. Based on the value of the composition index f1, the hot extrusion temperature and the hot forging temperature are changed for each sample.

  About the round bar extrusion material produced by the above-mentioned manufacturing process P1, the area ratio which β phase and γ phase occupy in the α phase matrix, the number density of β phase, tensile strength, 0.2% proof stress, machinability evaluated. The results are shown in Tables 3 and 4. Moreover, about the bus bar extrusion material produced at the manufacturing process P2, the antibacterial property and anticorrosion after a discoloration resistance, antibacterial property, and a discoloration resistance test were evaluated. The results are shown in Tables 5 and 6. The same items as the bus bar extruded material produced in the production process P2 were also evaluated for the flat forging material produced in the production process P3. The results are shown in Tables 7 and 8. Furthermore, about the grip produced by the manufacturing process P4, the moldability at the time of hot forging, tensile strength, and 0.2% yield strength were evaluated. The results are shown in Tables 9 and 10.

(Area ratio occupied by β phase and γ phase)
About the cross section parallel to the extrusion direction of the round bar extruded material produced in the production process P1, the area ratio occupied by the β phase and the γ phase in the α phase matrix was measured. Specifically, a tissue photograph was taken at a magnification of 500 using an inverted metal microscope (ECLIPSE MA200) manufactured by Nikon Instruments Company, Ltd., and β phase and γ in an α phase matrix using image analysis software (Winroof 2013). Each phase was binarized, and the area ratio occupied by the β phase and the γ phase was measured. The area ratios of the β phase and the γ phase are measured at any three locations (the size of one location is 221 μm × 277 μm) and the average value is used as data.

(Number density of β phase)
About the cross section along the extrusion direction of the round bar extrusion material produced in the manufacturing process P1, the number density of β phase is a structure photograph (magnification 200 times) using an inverted metal microscope (ECLIPSE MA200) manufactured by Nikon Instruments Co., Ltd. 553 μm × 692 μm) were taken with the β-phase longitudinal direction aligned with the longitudinal direction of the photograph, and 3 at equal intervals (138 μm interval) in a direction perpendicular to the longitudinal direction of any β-phase in the tissue photograph. Draw a line, calculate the average value of the number of β phases across each drawn line in three photographs, and calculate the average value of the number of β phases obtained by the length of the line drawn over the β phase. The number density was measured by dividing by the length (553 μm, which is the length in the short direction of the photograph).

(Tensile strength, 0.2% proof stress)
The hot-extrusion φ22.5mm round bar extruded material produced in the P1 process is used as the No. 4 test piece of metal material tensile test piece (bar: diameter: 14 mm, distance between gauge points: 50 mm) specified in JIS Z 2201. processed. In addition, a sample of the grip shape obtained in the P4 process is a No. 13B test piece of metal material tensile test piece specified in JIS Z 2201 (plate material: parallel part width 12.5 mm, thickness 3 mm, distance between gauge points. 50 mm), and a tensile test was performed using a 100 kN universal testing machine (AG-X, manufactured by Shimadzu Corporation). Tensile strength and 0.2% proof stress were measured by a tensile test. In the embodiments and examples of the present invention, “proof strength” means 0.2% proof stress specified in JIS Z 2241, that is, offset method described in the metal material tensile test method of JIS Z 2241. It means the yield strength when the permanent elongation obtained by is 0.2%.

(Discoloration resistance)
The discoloration resistance test was conducted using the bus bar extruded material produced in the P2 process and the flat forging material produced in the P3 process. The surface of the flat forged material and the bus bar extruded material that can take the maximum area was polished with # 1200 emily paper, and then subjected to a discoloration resistance test. In the discoloration resistance test method, each sample was exposed to an atmosphere at a temperature of 60 ° C. and a relative humidity of 95% by using a constant temperature and humidity chamber (HIFLEX FX2050, Enomoto Kasei Co., Ltd.). The test time was 12 hours, a sample was taken out after the test, and the surface color of the material before and after exposure was measured with a spectrocolorimeter to measure L * a * b *, and the color difference was calculated and evaluated. In Tables 5 to 8, as 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. That is, the smaller the color difference, the smaller the change in color tone, and thus the better the resistance to discoloration. When the color difference is 10 or more, it can be confirmed that the color is sufficiently discolored by visual observation, and it can be determined that the discoloration resistance is poor.

  As a comparative material, C2600 (70-30 brass, alloy No. B1) and C2800 (60-40 brass, alloy No. B2) were similarly evaluated for discoloration resistance. C2600 and C2800 were subjected to rust prevention treatment (treatment using a commercially available rust prevention liquid for copper alloy) 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 an aqueous solution containing 0.1 vol% of a commercially available rust prevention liquid for copper alloys whose main component is benzotriazole is heated to 75 ° C. Each material was soaked for 10 seconds, then washed with water and hot water to prepare a final blower-dried material. This is a condition similar to a general copper alloy rust prevention treatment condition (rust prevention treatment condition during mass production).

(Antibacterial)
The antibacterial property (bactericidal property) was performed using a sample obtained by cutting out the central part of the portion where the area could be taken most in the bus bar extruded material obtained in the P2 step and the flat forged material obtained in the P3 step into 25 mm squares. The test method was evaluated by a method referring to a test method defined in JIS Z 2801. The bacterium used in the test is Staphylococcus aureus (strain storage number: ATCC 6538), and 5.6 of JIS Z 2801. Tested a solution prepared by diluting Staphylococcus aureus pre-cultured at 35 ± 1 ° C. with 1/500 NB based on the method specified in Item a and adjusting the Staphylococcus aureus to 1.0 × 10 ⁶ cells / ml. Bacterial fluid was used. In the test method, a sample processed to a predetermined size is placed in a sterilized petri dish, 0.045 ml of the above-mentioned test bacterial solution (Staphylococcus aureus: 1.0 × 10 ⁶ cells / ml) is dropped, and a φ15 mm film is covered. And closed the petri dish lid. The petri dish is cultured for 10 minutes (inoculation time: 10 minutes) in an atmosphere of 35 ± 1 ° C. and a relative humidity of 95%. 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. 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 antibacterial test (cfu / ml)), it was compared with the number of live bacteria in each sample. The results were evaluated in Tables 5 to 8 as “A”: less than 10%, “B”: less than 10 to 33%, and “C”: 33% or more. It was judged that the sample that obtained an evaluation of “A” or more (that is, the viable cell count of the evaluation sample was less than 1/3 of the viable cell count at the time of inoculation) was excellent in antibacterial property (bactericidal property).

(Antimicrobial test after discoloration resistance test)
The antibacterial property test was performed using the sample whose surface was discolored to some extent after the discoloration resistance test of the bus bar extruded material obtained in the P2 step and the flat forged material obtained in the P3 step. The antibacterial test method is the same as the above-described antibacterial test method. Evaluation of antimicrobial (bacteriocidal) is viable cell ratio C _H were carried out in samples after discoloration resistance test, relative viable cell ratio C ₀ of the sample that is not the discoloration resistance test, C _H ≦ 1. The case of 10 × C ₀ is “A”, the case of 1.10 × C ₀ <C _H ≦ 1.25 × C ₀ is “B”, and the case of C _H > 1.25 × C ₀ is “C”. did. That is, there is a concern that the antibacterial performance may be deteriorated when the copper alloy is discolored, and a slight discoloration is recognized even in the alloys of the present invention (alloys Nos. 1 to 24) by the severe discoloration resistance test under the high temperature and high humidity. Thus, it was predicted that oxides and the like were generated in the surface extreme surface layer portion. Even in such a slightly discolored sample, it was judged that the antibacterial performance was not impaired if it was evaluated A and at least evaluated B, compared to the sample having a clean surface before the test.

(Corrosion resistance)
The corrosion resistance test was performed using the flat forged material obtained in the P3 step and the bus bar extruded material obtained in the P2 step.
The test method was evaluated by a dezincification corrosion test specified by ISO 6509: 1981 (Corrosion of metals and alloys determination of dezincification resistance of brass). Similar to the discoloration resistance test, the processed flat forging is cut out so that the center of the surface where the maximum area can be taken is exposed, and the surface is polished with # 1200 Emily paper so that the exposed surface becomes 1 cm ^2. Masking was performed with a heat-resistant resin tape and exposed to the test solution for 24 hours. A 1% aqueous cupric chloride solution heated to 75 ° C. was used as a test solution. The samples held for 24 hours were observed in the metal structure in the vertical direction from the exposed surface, and the depth (maximum dezincification corrosion depth) of the portion where dezincification corrosion was most advanced was measured. Those whose maximum dezincification corrosion depth is 200 μm or less are listed in Tables 5 to 8 as “A”, and those having more than 200 μm as “C”.

(Machinability)
A φ20 mm rod-shaped cutting test piece was collected from the φ22.5 mm round bar extruded material obtained in the P1 process after hot extrusion, the outer periphery was cut without lubrication, the chips were collected, and the thickness of the chips was measured. . Cutting the outer circumference from φ20mm to φ18mm (cutting 1mm on one side), cutting speed is 150m / min, feed is 0.2mm / rev, insert is TNGG 160404R (material UTi20T) made by Mitsubishi Materials, cutting distance is 9.4m Went. A chip thickness of less than 350 μm was evaluated as “A”, 350 to 420 μm was evaluated as “B”, and an excess of 420 μm was evaluated as “C”.

(Formability during hot forging: P4 process)
Hot forging in the P4 process, that is, the 22.5 mm round bar extruded material obtained after the hot extrusion obtained in the P1 process is cut into a length of 240 mm, heated in a furnace to a predetermined temperature T2 (° C.), and gripped. Evaluation was made based on the presence or absence of surface cracks in the grip and the dimensions after molding when hot forging into the shape. FIG. 1 shows a cross-sectional view of the grip. C, with no defects such as surface cracks, ear cracks, or defects such as molding defects (thinning) or lack of dimensional accuracy. A good one with high accuracy was evaluated as A. As for the dimensional accuracy, the target values of the thicknesses of the arrows A and B shown in FIG. Judgment by whether or not. That is, if the thicknesses of the arrows A and B are within the ranges of 11.3 to 12.0 mm and 12.3 to 13.0 mm, respectively, it is determined that the dimensional accuracy is high. Here, the thicknesses of the arrows A and B mean the dimensions of the arrows A and B in the Y direction. Moreover, the parts indicated by arrows A and B in FIG. 1 are 53 to 56 mm along the X direction from the left end in the X direction and 81 to 81 from the right end with respect to the total length of 240 mm in the longitudinal direction (X direction) of the grip. It is a 84 mm portion. If the thickness (dimension in the Y direction) at these portions was within the above range, it was judged that the dimensional accuracy had come out.

As a result of the above test, the following was found.
Alloy No. corresponding to the first invention alloy rod 1 to 22, that is, 30.0 to 42.0 mass% Zn, 0.0005 to 0.30 mass% Pb, 0.01 to 11.0 mass% Ni, and 0.01 to 1.5 mass% In addition, 0.01 to 1.2 mass% Al, 0.01 to 1.2 mass% Mn, 0.005 to 0.07 mass% As, 0.005 to 0.07 mass% P, 0.005 to 0.07 mass% of any one of Sb, and the balance is a copper alloy rod made of Cu and inevitable impurities, 33.0 ≦ f1 ≦ 38.0, and f2 ≦ 4.8, and 1.5 ≦ (β) + (γ between the area ratio (β)% of the β phase and the area ratio (γ)% of the γ phase in the α phase matrix. ) ≦ 14.0 and the length of β phase in any cross section A copper alloy bar having a metal structure in which the number density of β phases crossing a straight line in a direction perpendicular to the direction is 9 to 29 pieces / mm is hot extrudability, hot forgeability, machinability and mechanical properties. The copper alloy was excellent in (tensile strength, 0.2% proof stress) and excellent in corrosion resistance, discoloration resistance, antibacterial properties and bactericidal properties.

  Furthermore, the alloy no. 13-22, ie, 33.0-38.0 mass% Zn, 0.0005-0.30 mass% Pb, 1.5-4.0 mass% Ni, and 0.1-1.2 mass% In addition, 0.01-0.5 mass% Al, 0.01-0.5 mass% Mn, 0.005-0.07 mass% As, 0.005-0.07 mass% P, 0.005 to 0.07 mass% of any one of Sb, and the balance is a copper alloy rod made of Cu and inevitable impurities, 34.0 ≦ f1 ≦ 38.0, and 3.6 ≦ f2 ≦ 4.5, and 1.5 ≦ (β between the area ratio (β)% of the β phase and the area ratio (γ)% of the γ phase in the α phase matrix. ) + (Γ) ≦ 14.0 and β phase in any cross section A copper alloy bar having a metal structure in which the number density of β phases crossing a straight line in a direction perpendicular to the longitudinal direction is 9 to 29 pieces / mm is hot extrudable, hot forgeable, machinable and mechanical properties. The copper alloy was excellent in anti-discoloration, antibacterial and bactericidal properties. In particular, even when the range of the addition amount of Ni, Mn, and Al was further limited than that of the first inventive alloy rod, the discoloration resistance performance was hardly impaired.

  Alloy No. whose Zn content is lower than the lower limit of the alloy rod of the present invention. In A7, discoloration resistance and machinability deteriorated, and alloy no. In A1, the antibacterial and corrosion resistance after the antibacterial and discoloration resistance tests deteriorated.

  Alloy No. having a Pb content equal to or lower than the lower limit of the alloy rod of the present invention. In A13, machinability decreased.

  Alloy No. whose Ni content exceeded the upper limit of the alloy rod of the present invention. In A4, machinability, antibacterial properties after the discoloration resistance test, and moldability during hot forging deteriorated. Alloy No. in which the Ni content falls within the optimum range of the alloy rod of the present invention In 13-22, it was recognized that antibacterial property improves further, without impairing discoloration resistance almost, and it was recognized that discoloration resistance and antibacterial property are compatible.

  Alloy No. whose Sn content exceeded the upper limit of the alloy rod of the present invention. In A9, the antibacterial properties, corrosion resistance, and hot forging moldability after the discoloration resistance test were deteriorated. Alloy No. with Sn content falling within the optimum range of the alloy rod of the present invention. In 8, 10-18, it was recognized that antibacterial property improves more.

  Alloy No. in which the Al content exceeds the upper limit of the alloy rod of the present invention. In A10, antibacterial properties and antibacterial properties after the discoloration resistance test deteriorated. Alloy No. 1 in which the Al content falls within a more preferable range in the alloy rod of the present invention. 7 and 8, an improvement in antibacterial properties after the discoloration resistance test was observed.

  Alloy No. whose Mn content exceeded the upper limit of the alloy rod of the present invention. In A5, the antibacterial property after the discoloration resistance test and the moldability at the time of hot forging deteriorated. Alloy No. 4 in which the Mn content falls within the optimum range of the alloy rod of the present invention. In Nos. 1 to 6, a decrease in antibacterial property was minimized while maintaining good discoloration resistance.

  Alloy No. with the contents of As, P and Sb set to appropriate amounts in the alloy rod of the present invention. In 10-22 and A14, the improvement of corrosion resistance was recognized.

  Alloy No. whose P content exceeded the upper limit of the alloy rod of the present invention. In A15, the formability during hot working deteriorated.

  Alloy No. with a composition index f1 of less than the lower limit in the alloy rod of the present invention. In A2 and A7, machinability, formability during hot working, strength, and discoloration resistance deteriorated. On the other hand, the alloy no. In A1, A8, A9, and A12, corrosion resistance and antibacterial properties deteriorated.

  Alloy No. having a composition index f2 of less than the lower limit in the alloy rod of the present invention. In A7, although antibacterial property was high, discoloration resistance became bad. On the other hand, Alloy No. with a composition index f2 exceeding the upper limit. In A1 and A3, the discoloration resistance improved, but the antibacterial properties deteriorated.

  Even if the value of the composition index f2 is within the preferable range of the alloy rod of the present invention, the alloy no. In 18, 20, 21, A5, A12, and A14 to A16, the antibacterial property slightly decreased.

  Alloy Nos. In which the values of the composition indexes f1 and f2 fall within the more optimal range of the alloy rod of the present invention. In 13-17, antibacterial property became higher, ensuring discoloration resistance.

  Alloy No. 1 in which the area ratio occupied by the β phase and the γ phase is less than the lower limit of the alloy rod of the present invention. In A2, A4, A7, and A11, machinability and formability during hot working deteriorated. On the other hand, the alloy No. in which the area ratio occupied by the β phase and the γ phase exceeded the upper limit of the alloy rod of the present invention. In A1, A8, and A12, corrosion resistance and discoloration resistance deteriorated.

  When the number density of β phases was less than 9 pieces / mm, machinability deteriorated even if the area ratio occupied by β phases and γ phases was within the appropriate range (alloy No. A6). Further, when the number density of β phases exceeds 29 / mm, the machinability is improved even if the area ratio occupied by β phases and γ phases is within an appropriate range, but the corrosion resistance and discoloration resistance are deteriorated. (Alloy No. A16).

  The comparative material C2600 (70-30 brass, alloy No. B1) had poor discoloration resistance and machinability and poor moldability during hot forging. C2800 (60-40 brass, alloy No. B2) had poor discoloration resistance and corrosion resistance.

  The alloy (alloy No. B3) described in Patent Document 2 as a comparative material had a poor yield and could hardly be extruded. A few samples were tested for machinability and formability during hot forging, both of which were bad.

  Although the strength of the hot forged material in the P3 process is slightly higher than that of the hot extruded material, the discoloration resistance, antibacterial properties, and antibacterial properties after the discoloration resistance test were equivalent to those of the hot extruded material.

  Since the copper alloy bar and copper alloy member of the present invention have excellent discoloration resistance, antibacterial properties, hot workability, machinability, corrosion resistance and mechanical properties, they are handrails, door knobs, doors in hospitals or public facilities. Handles, lever handles, poles, desks, chairs, shelves, nur skirt handle members, bedside rails, drip gantry grips, writing instruments, companion vehicles, carts, food and other transport carts, carts, desks and chair components , Key material, medical instrument member, valve handle, indoor electrical switch, mechanical device button, western tableware, musical instrument, nickel plating, etc.

Claims (4)

Contains 30.0-42.0 mass% Zn, 0.0005-0.30 mass% Pb, 0.01-11.0 mass% Ni, and 0.01-1.5 mass% Sn. ,
Furthermore, 0.01-1.2 mass% Al, 0.01-1.2 mass% Mn, 0.005-0.07 mass% As, 0.005-0.07 mass% P, 0.005- Contains any one or more of 0.07 mass% Sb,
The balance is a copper alloy rod made of Cu and inevitable impurities,
Zn content [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al ] Between mass%, Mn content [Mn] mass%, As content [As] mass%, P content [P] mass%, and Sb content [Sb] mass% 33.0 ≦ [Zn] −0.5 × [Pb] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] +0.5 × [As] + 2.0 × [P] + 2.5 × [Sb] ≦ 38.0, and 3.3 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [ Ni]) + 0.7 × [Sn] + 1.8 × [Al] ≦ 4.8
Between the β phase area ratio (β)% and the γ phase area ratio (γ)% in the α phase matrix, there is a relationship of 1.5 ≦ (β) + (γ) ≦ 14.0,
A copper alloy bar characterized by having a metal structure in which the number density of β phases crossing a straight line perpendicular to the longitudinal direction of β phases in an arbitrary cross section is 9 to 29 pieces / mm. 33.0 to 38.0 mass% Zn, 0.0005 to 0.30 mass% Pb, 1.5 to 4.0 mass% Ni, and 0.1 to 1.2 mass% Sn ,
Furthermore, 0.01 to 0.5 mass% Al, 0.01 to 0.5 mass% Mn, 0.005 to 0.07 mass% As, 0.005 to 0.07 mass% P, 0.005 Contains any one or more of 0.07 mass% Sb,
The balance is a copper alloy rod made of Cu and inevitable impurities,
Zn content [Zn] mass%, Pb content [Pb] mass%, Sn content [Sn] mass%, Ni content [Ni] mass%, and Al content [Al ] Between mass%, Mn content [Mn] mass%, As content [As] mass%, P content [P] mass%, and Sb content [Sb] mass% 34.0 ≦ [Zn] −0.5 × [Pb] + 3.6 × [Sn] −0.4 × [Ni] + 2.4 × [Al] −0.5 × [Mn] +0.5 × [As] + 2.0 × [P] + 2.5 × [Sb] ≦ 38.0 and 3.6 ≦ 0.05 × [Zn] + 3.0 × exp (−1 / [ Ni]) + 0.7 × [Sn] + 1.8 × [Al] ≦ 4.5,
Between the β phase area ratio (β)% and the γ phase area ratio (γ)% in the α phase matrix, there is a relationship of 1.5 ≦ (β) + (γ) ≦ 14.0,
A copper alloy bar characterized by having a metal structure in which the number density of β phases crossing a straight line perpendicular to the longitudinal direction of β phases in an arbitrary cross section is 9 to 29 pieces / mm.   A copper alloy member comprising a hot forged material formed by hot forging the copper alloy bar according to claim 1.   Construction of handrails, door knobs, door handles, lever handles, poles, desks, chairs, shelves, nur skirt handle members, bedside rails, grips, writing instruments, companion vehicles, carts, carriages for meals, carts, desks and chairs The copper alloy member according to claim 3, wherein the copper alloy member is used as a member, a key member, a member of a medical instrument, a valve handle, an indoor electric switch, a button of a mechanical device, a western tableware, and a musical instrument.

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