JPWO2017204252A1 - Brass alloy hot-worked product and method for producing brass alloy hot-worked product - Google Patents

Abstract

One aspect of this brass alloy hot-worked product is Cu: 61.5-64.5 mass%, Pb: 0.6-2.0 mass%, Sn: 0.55-1.0 mass%, Sb: 0.02 -0.08 mass%, Ni: 0.02-0.10 mass% is included, the remainder consists of Zn and an inevitable impurity, and the following formula | equation is satisfied.
60.5 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 64.0
0.03 ≦ [Sb] / [Sn] ≦ 0.12
0.3 ≦ [Ni] / [Sb] ≦ 3.5

Description

The present invention relates to a brass alloy hot-worked product excellent in corrosion resistance (a hot-worked product of brass alloy) and a method for producing the brass alloy hot-worked product.
This application claims priority on May 25, 2016 based on Japanese Patent Application No. 2016-104136 for which it applied to Japan, and uses the content here.

As the above-mentioned brass alloy hot-worked material (hot extruded rod or hot forged product), since it is excellent in machinability (cutability) or forgeability, it is mainly JIS H3250 C3604 (free-cutting brass) or C3771. (Brass for forging) is used.
However, these brass alloy materials are used in a corrosive environment that comes in contact with tap water such as faucet equipment because the metal structure is composed of an α phase and a β phase and many β phases with poor corrosion resistance are included. Then, dezincification corrosion easily occurs, and problems such as water leakage occur due to aging corrosion.

  Here, in order to improve the dezincification resistance of the brass alloy material, a γ phase having an area ratio of 5% or more may be precipitated. Patent Document 1 discloses a dezincing-resistant brass joint member containing 1.5 mass% or more of Sn in the β phase. In Patent Document 2, Cu: 61.0 to 63.0 mass%, Pb: 2.0 to 4.5 mass%, P: 0.05 to 0.25 mass%, Ni: 0.05 to 0.30 mass %, A material with improved anti-dezincing corrosion resistance made of a copper-based alloy with the balance being Zn has been proposed.

The alloy disclosed in Patent Document 1 is an alloy containing a lot of hard and brittle γ-phase, and there is a problem that cracking is likely to occur in a water hammer phenomenon in a faucet device where a sudden force is applied. is there. In addition, the γ phase is more excellent in dezincification corrosion resistance than the β phase, but is inferior to the α phase. Therefore, when it is present in a large amount, dezincification corrosion occurs preferentially in the γ phase.
On the other hand, since the copper-based alloy disclosed in Patent Document 2 does not contain Sn, the resistance to substantial dezincification is inferior, and when it contains a large amount of P, it causes cracks during casting. There is also a problem.

JP 2002-066952 A JP-A-11-131158

  The present invention has been made in order to solve the above-described problems of the prior art, and has excellent corrosion resistance such as anti-zinc corrosion resistance, and hot-worked brass alloy and hot-worked brass alloy. It is an object to provide a method for manufacturing a processed product.

The present invention has been made on the basis of such knowledge, and the brass alloy hot-worked product according to the first aspect of the present invention has Cu: 61.5 mass% or more and 64.5 mass% or less, Pb: 0.0. 6 mass% or more and 2.0 mass% or less, Sn: 0.55 mass% or more and 1.0 mass% or less, Sb: 0.02 mass% or more and 0.08 mass% or less, Ni: 0.02 mass% or more and 0.10 mass% or less The balance is made of Zn and inevitable impurities, the Cu content is [Cu] mass%, the Pb content is [Pb] mass%, the Sn content is [Sn] mass%, and the Sb content is [Sb ] Mass%, when the content of Ni is [Ni] mass%,
60.5 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 64.0,
0.03 ≦ [Sb] / [Sn] ≦ 0.12,
0.3 ≦ [Ni] / [Sb] ≦ 3.5,
It is characterized by satisfying.

The brass alloy hot-worked product according to the second aspect of the present invention is Cu: 62.0 mass% or more and 64.0 mass% or less, Pb: 0.7 mass% or more and 2.0 mass% or less, Sn: 0.60 mass% or more 0.95 mass% or less, Sb: 0.03 mass% or more and 0.07 mass% or less, Ni: 0.025 mass% or more and 0.095 mass% or less, and the balance is made of Zn and inevitable impurities, and the content of Cu is [ Cu] mass%, Pb content is [Pb] mass%, Sn content is [Sn] mass%, Sb content is [Sb] mass%, and Ni content is [Ni] mass%. In case,
60.7 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 63.6,
0.035 ≦ [Sb] / [Sn] ≦ 0.10,
0.4 ≦ [Ni] / [Sb] ≦ 3.5,
It is characterized by satisfying.

  The brass alloy hot-worked product according to the third aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and the β-phase area ratio and the γ-phase. The area ratio of the total area ratio is 0% or more and 5% or less.

  The brass alloy hot-worked product according to the fourth aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and each of the β-phase or γ-phase. The long side length is 100 μm or less.

  The brass alloy hot-worked product according to the fifth aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and the average particle size of the Pb particles is 0. .2 μm or more and 3 μm or less.

The brass alloy hot-worked product according to the sixth aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, contains Pb particles, and the distribution of Pb particles is 0.002. It is characterized by the number of pieces / 100 μm ² or more and 0.06 pieces / 100 μm ² or less.

The brass alloy hot-worked product according to the seventh aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and the average particle size of the Pb particles is 0. .2μm or more and 3μm or less, and the distribution of Pb particle 0.002 / 100 [mu] m ² or more, characterized in that 0.06 units / 100 [mu] m ² or less.

  The brass alloy hot-worked product according to the eighth aspect of the present invention is the above-described brass alloy hot-worked product, and is characterized by being used as a water supply device.

  The method for producing a brass alloy hot-worked product according to the ninth aspect of the present invention is a method for producing a brass alloy hot-worked product for producing the above-described brass alloy hot-worked product, and is 670 ° C. or higher and 820 ° C. or lower. And a temperature region from 620 ° C. to 450 ° C. is cooled at an average cooling rate of 200 ° C./min or less.

  A method for manufacturing a brass alloy hot-worked product according to a tenth aspect of the present invention is the above-described method for manufacturing a brass alloy hot-worked product, wherein, after the hot working, a temperature of 470 ° C. or more and 560 ° C. or less is 1 It is characterized by performing a heat treatment for holding for 8 minutes or more.

  According to the aspect of the present invention, it is possible to provide a brass alloy hot-worked product and a brass alloy hot-worked product manufacturing method that are excellent in corrosion resistance such as dezincification corrosion resistance and excellent in hot workability.

It is explanatory drawing which shows the metal structure observation position of the hot extrusion material in an Example. It is explanatory drawing which shows the metal structure observation position of the hot forging material in an Example.

Below, the manufacturing method of the brass alloy hot work goods and brass alloy hot work goods which concern on embodiment of this invention is demonstrated.
The brass alloy hot-worked product according to the present embodiment is used as a water supply device such as a water tap fitting, a joint, or a valve. Moreover, the brass alloy hot-worked product which is this embodiment is a brass alloy hot-extrusion rod or a brass alloy hot-forged product.

Here, in the present specification, an element symbol in parentheses such as [Zn] indicates the content (mass%) of the element.
And in this embodiment, using this content display method, a plurality of compositional relational expressions are defined as follows.
Composition relation f1 = [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni]
Composition relation f2 = [Sb] / [Sn]
Composition relation f3 = [Ni] / [Sb]

  The brass alloy hot-worked product according to the first embodiment of the present invention is Cu: 61.5 mass% to 64.5 mass%, Pb: 0.6 mass% to 2.0 mass%, Sn: 0.55 mass% 1.0 mass% or less, Sb: 0.02 mass% or more and 0.08 mass% or less, Ni: 0.02 mass% or more and 0.10 mass% or less, and the balance is composed of Zn and inevitable impurities. Within the range of 60.5 ≦ f1 ≦ 64.0, the composition relational expression f2 is within the range of 0.03 ≦ f2 ≦ 0.12, and the compositional relational expression f3 is within the range of 0.3 ≦ f3 ≦ 3.5. ing.

  The brass alloy hot-worked product according to the second embodiment of the present invention is Cu: 62.0 mass% to 64.0 mass%, Pb: 0.7 mass% to 2.0 mass%, Sn: 0.60 mass% 0.95 mass% or less, Sb: 0.03 mass% or more and 0.07 mass% or less, Ni: 0.025 mass% or more and 0.095 mass% or less, and the balance is composed of Zn and inevitable impurities. Within the range of 60.7 ≦ f1 ≦ 63.6, the composition relational expression f2 is within the range of 0.035 ≦ f2 ≦ 0.10, and the compositional relational expression f3 is within the range of 0.4 ≦ f3 ≦ 3.5. ing.

In the brass alloy hot-worked products according to the first and second embodiments of the present invention described above, the metal structure is an α-phase matrix, includes Pb particles, the β-phase area ratio and the γ-phase area. The total area ratio is set to 0% or more and 5% or less.
Further, the length of each long side of the β phase or γ phase is set to 100 μm or less.

  The reason why the component composition, the composition relational expressions f1, f2, and f3 and the metal structure are defined as described above will be described below.

(Cu)
Cu is a main element constituting the alloy of the present invention, and is greatly influenced by the relationship with Sn, Pb, Zn, but is a hot-worked material of the alloy of the present invention, a hot extruded material, and a hot forged product In order to have excellent corrosion resistance and dezincification corrosion resistance, Cu needs to be 61.5 mass% or more, preferably 62.0 mass% or more. On the other hand, if the Cu content exceeds 64.5 mass%, the proportion of β phase or the like that lowers the deformation resistance during hot working, that is, hot extrusion and hot forging, decreases. For this reason, the hot deformation resistance increases, and the hot working temperature for appropriate hot working increases. Moreover, not only hot extrudability and hot forgeability, which are hot workability, are deteriorated, but also machinability is deteriorated, strength is lowered, and corrosion resistance is saturated. For this reason, the upper limit of the Cu content is 64.5 mass% or less, preferably 64.0 mass% or less.

(Pb)
Pb is contained in order to improve machinability (machinability). For that purpose, Pb needs to be 0.6 mass% or more. Preferably it is 0.7 mass% or more, and is 1.0 mass% or more particularly when machinability is required. The machinability improves as the Pb content increases. On the other hand, if Pb is contained in excess of 2.0 mass%, the amount of elution into water increases and the environmental load may increase. Therefore, the upper limit of the Pb content is set to 2.0 mass% or less.
Note that Pb is present as Pb particles because it hardly dissolves in the parent phase of the copper alloy. The size and distribution of the Pb particles greatly affect the machinability (machinability) and also affect the elution amount of Pb. In order to improve the machinability (machinability), it is desired that the Pb particles have a small size and are uniformly distributed at a high density. On the other hand, with respect to the amount of Pb eluted, the larger the area of Pb particles in contact with an aqueous solution such as tap water that is in contact with, the larger the amount of elution, so that the size of Pb particles contrary to machinability (machinability) and Distribution. Therefore, there is an appropriate range for the size and distribution of the Pb particles in order to balance the machinability (machinability) and elution amount necessary for the alloy of the present invention so as not to be a problem. For machinability (machinability), the average particle size of the Pb particles needs to be 0.2 μm or more and 3 μm or less. When the average particle diameter of the Pb particles exceeds 3 μm, the Pb particles are stretched to the cutting surface at the time of cutting, but the area of the Pb increases. For this reason, as a result, the area of Pb which contacts tap water becomes large and the elution amount of Pb increases. When the average particle diameter is less than 0.2 μm, the particles are small and do not serve as a chip breaker for improving the machinability.
The distribution of Pb particles is indicated by the number (density) of Pb particles present per cross-sectional area of 100 μm ² . Distribution of Pb particle (density) 0.002 / 100 [mu] m ² or more, as long as 0.06 pieces / 100 [mu] m ² or less, which contributes to cutting performance (machinability). If the distribution of Pb particles is less than 0.002 particles / 100 μm ² , the presence of Pb particles is low and does not serve as a chip breaker, resulting in a low machinability index (less than 75%).
Further, the distribution of Pb particles is more advantageous from the viewpoint of machinability (machinability), but it is better from the viewpoint of elution of Pb. When the Pb particles come into contact with the cutting tool at the time of cutting, the Pb particles are partly dissolved by the heat generated at that time and are stretched in the moving direction of the cutting tool, so that the Pb particles are substantially present in a wide range of the cutting surface. Therefore, if the distribution of Pb particles is large, the amount of Pb present on the surface after cutting inevitably increases, and the amount of Pb elution increases inevitably. When the leaching amount (elution amount) of Pb is measured by JIS S3200-7 (water supply equipment-leaching performance test method), the average particle size of Pb particles is well above 0.007 mg / L even when the volume is corrected. Is over 3 μm, and the particle distribution is over 0.06 particles / 100 μm ² . In addition, 0.007mg / L of the lead leaching amount (elution amount) is the upper limit (when using a copper alloy as the main member) for the leachate in the end faucet described in Ordinance No. 1 of the Ministry of Health, Labor and Welfare Yes, materials that exceed this standard cannot be used as the end faucet.
Therefore, the upper limit of the distribution (density) of the Pb particles is set to 0.06 particles / 100 μm ² or less, which does not cause a problem in the dissolution amount (leaching amount).
From the above, the average particle diameter of the Pb particles is 0.2 to 3 μm, and the distribution is 0.002 to 0.06 particles / 100 μm ² .

(Sn)
Sn is greatly influenced by the relationship with Cu and Zn, but improves the corrosion resistance under severe water quality for copper alloys, particularly dezincification corrosion resistance. Furthermore, Sn lowers the deformation resistance during hot working, that is, during hot extrusion and during hot forging. In order to achieve these, Sn is required to be 0.55 mass% or more, preferably 0.60 mass% or more, and more preferably 0.65 mass% or more. On the other hand, if the Sn content exceeds 1.0 mass%, the proportion of the γ phase or β phase increases, and the corrosion resistance becomes a problem. For this reason, the upper limit of the Sn content is 1.0 mass% or less, and preferably 0.95 mass% or less.

(Sb)
Sb has a function of improving the corrosion resistance under severe water quality for copper alloys, in particular, dezincification corrosion resistance, and exhibits its effect even more when Sn and Ni are added together. In order to exhibit excellent corrosion resistance, Sb is required to be 0.02 mass% or more, preferably 0.03 mass% or more, more preferably 0.035 mass% or more. On the other hand, even if Sb exceeds 0.08 mass%, not only the effect is saturated, but also hot workability is adversely affected, and cold workability is also deteriorated. For this reason, the upper limit of the Sb content is 0.08 mass% or less, preferably 0.07 mass% or less, and more preferably 0.065 mass% or less.

(Ni)
Ni co-adds with Sn and Sb, and improves the corrosion resistance and the dezincification corrosion resistance in harsh water quality for copper alloys, and in particular has the function of maximizing the effect of Sb. In order to exhibit excellent corrosion resistance, Ni is required to be 0.02 mass% or more, preferably 0.025 mass% or more. On the other hand, when Ni is contained exceeding 0.10 mass%, there is a possibility that the elution amount of Ni increases under severe water quality. For this reason, the upper limit of the Ni content is 0.10 mass% or less, preferably 0.095 mass% or less.

(Inevitable impurities)
For copper alloys containing Pb, cutting chips and waste products are used as main raw materials in terms of recycling and cost. For example, several kinds of elements such as Fe are mixed into the cutting chips due to tool wear or the like. Waste products may be plated with Cr or the like. Since they are used as raw materials, inevitable impurities are mixed in more than other copper alloys. For example, with respect to the amount of Fe treated as an impurity, a copper alloy (C3604) containing about 3 mass% Pb specified by JIS H 3250 and a copper alloy (C3605) containing about 4 mass% Pb are set to 0. Up to 5 mass% is allowed.
Therefore, in the alloy of the present invention, inevitable impurities such as Fe, Cr, Mn, and Al are allowed up to 1.0 mass% in total on the premise that the characteristics are not seriously affected.
P, like Sb, functions to improve the corrosion resistance of the copper alloy. However, if P is mixed even in a small amount, cracks are likely to occur on the surface or inside during the production of the ingot, and cracks are likely to occur on the material surface during hot working. Although it depends on the contents of Cu, Pb, Sn, and Ni, for example, if the P content exceeds 0.02 mass%, problems occur during ingot creation and hot processing, so P is mixed. However, the upper limit value is preferably 0.02 mass% or less.

(Composition relational expression f1)
In order to exhibit excellent corrosion resistance and to ensure good hot workability, it is not sufficient to specify the range of the content of each element such as Cu, Sn, Ni and the like. The Cu content is [Cu] mass%, the Pb content is [Pb] mass%, the Sn content is [Sn] mass%, the Sb content is [Sb] mass%, and the Ni content is [ When Ni] mass%, the compositional relational expression f1 = [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] is preferably less than 60.5. Corrosion resistance is not obtained. Furthermore, excellent corrosion resistance cannot be exhibited even if heat treatment is performed in the process after hot working (hot extrusion, hot forging).
Therefore, the lower limit of the compositional relational expression f1 is 60.5 or more, preferably 60.7 or more, more preferably 61.0 or more.
On the other hand, when the value of the compositional relational expression f1 = [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] exceeds 64.0, the deformation resistance in the hot state is increased. In addition, the hot deformability deteriorates, and good hot workability, that is, hot extrudability and hot forgeability cannot be ensured. For example, depending on the hot working temperature and equipment capacity, good hot workability means that for hot extrusion, there is no crack on the surface of the extruded rod, and it is the smallest dimension that is practically used, φ12mm. Whether it can be extruded. About hot forging, it is whether cracking does not occur on the surface of a forged product and thin wall forging is possible.
Therefore, the upper limit of the compositional relational expression f1 is 64.0 or less, preferably 63.6 or less, and more preferably 63.0 or less.

(Composition relational expression f2)
By simply containing Sb and Sn in a predetermined amount, particularly excellent corrosion resistance and dezincification corrosion resistance cannot be obtained. Both Sn and Sb elements are more solidly dissolved in the β phase, which is stable at a high temperature of 600 ° C. or higher, than the α phase of the matrix. Alternatively, Sn and Sb are more dissolved in the γ phase which is stable at a low temperature of 475 ° C. or less, particularly 450 ° C. or less than the α phase of the matrix. Although depending on the ratio of the α phase of the matrix to the β phase and / or the γ phase, if the composition of the alloy of the present invention is used, the amount of Sn and Sb dissolved in the β phase will be solid solution in the α phase. Approximately 2 to 7 times more than the amount of Sn and Sb. Further, the amount of Sn and Sb dissolved in the γ phase is approximately 7 to 15 times larger than the amount dissolved in the α phase. First, in order to improve the corrosion resistance of the α phase of the matrix, the abundance ratio of Sb and Sn is important, and it is assumed that Sb and Sn are in the above composition range. When the compositional relational expression f2 = [Sb] / [Sn] is 0.03 ≦ f2 ≦ 0.12, the effect of co-addition of Sn and Sb becomes more remarkable, and the corrosion resistance of the α phase is most improved. . Preferably, the lower limit of the compositional relational expression f2 is 0.035 or more, and the upper limit of the compositional relational expression f2 is 0.10 or less.

Regarding the β phase of the Cu—Zn—Sn alloy, it is difficult to make it particularly excellent in corrosion resistance, but the compositional relational expression f2 = [Sb] / [Sn] is 0.03 ≦ f2, preferably When 0.035 ≦ f2 is satisfied, the corrosion resistance of the β phase is improved, and the corrosion resistance of the extruded material or the forged product is improved. The alloy of the present invention enhances hot workability by generating a β phase with low hot deformation resistance at high temperatures. However, as the temperature decreases, the β phase changes to an α phase and the corrosion resistance increases. It is done. However, crystal grain boundaries and phase boundaries that change from the β phase to the α phase have a problem in corrosion resistance. When the value of the compositional relational expression f2 = [Sb] / [Sn] is at least 0.03 and not more than 0.12, the corrosion resistance of the crystal grain boundary and the phase boundary is improved.
At a temperature of 475 ° C. or lower or 450 ° C. or lower, when the β phase changes to the α phase, the concentration of Sn and Sb dissolved in the β phase is further increased, so that the γ phase is generated. When 0.03 ≦ f2 ≦ 0.12, the grain boundaries of the α phase and the γ phase, the phase boundary, and the corrosion resistance of the γ phase itself are further improved.
Regarding the deformability at high temperature, when the compositional relational expression f2 = [Sb] / [Sn] exceeds 0.12, the amount of Sb becomes excessive as compared with Sn, and the deformability between the α phase and the β phase in the heat. Decreases and hot workability deteriorates.

(Composition relational expression f3)
Similar to the composition relational expression f2 = [Sb] / [Sn], the relationship between Ni and Sb is also important. Due to the presence of Ni, the effect of Sb is further enhanced on the corrosion resistance of the α phase and γ phase of the matrix, and the corrosion resistance of the β phase is also enhanced. In particular, grain boundaries and phase boundaries when changing from β phase, which is stable at high temperature, to α phase, and phase boundaries when changing from β phase to γ phase and α phase on the low temperature side, and corrosion resistance of γ phase To improve. In order to exert these effects, the value of the compositional relational expression f3 = [Ni] / [Sb] is 0.3 or more, preferably 0.4 or more. The upper limit is not particularly limited in the Ni composition range of the alloy of the present invention, but considering that the effect is saturated, the value of the composition relational expression f3 = [Ni] / [Sb] is set to 3.5 or less. .

(Metal structure)
In order to ensure good hot workability, it is an essential requirement that the β phase exists at the hot working temperature. The β phase generated at a high heating temperature or processing temperature changes to an α phase or a γ phase as the temperature decreases. Depending on the production process, even the composition of the alloy of the present invention may leave a β phase having a problem in corrosion resistance and a γ phase. By adding the above Sn, Sb, and Ni so that the composition relational expression f2 = [Sb] / [Sn] and the composition relational expression f3 = [Ni] / [Sb] are appropriate, the β phase, γ Since the corrosion resistance of the phase is improved, there is no problem in general water quality, but it is not sufficient in a harsh environment.

  That is, the total proportion of the β phase and γ phase contained in the metal structure exceeds 5% in area ratio, and the long side length of each of the β phase or γ phase in the microscopic observation of an arbitrary cross section However, if it exceeds 100 μm, it cannot withstand the corrosion resistance in a harsh environment. Since the anti-dezincification corrosion resistance of the β phase or γ phase is lower than that of the α phase, if they are present in the metal structure, they may preferentially exhibit dezincification corrosion. That is, when the length of the long side exceeds 100 μm, the dezincification corrosion depth may exceed 100 μm, which causes a problem in corrosion resistance. Therefore, the total proportion of β phase and γ phase contained in the metal structure is 0% or more and 5% or less in terms of area ratio, or the length of each long side of β phase or γ phase is , 100 μm or less is necessary. When the total proportion of the β phase and the γ phase is 0% or more and 5% or less in terms of area ratio, the β phase area ratio is preferably 0% or more and 3% or less. More preferably, the total proportion of β phase and γ phase contained in the metal structure is 5% or less in terms of area ratio, and the length of each long side of the β phase or γ phase is 100 μm or less. It is. Best, the total proportion of β phase and γ phase is 0% or more and 5% or less in area ratio, and the area ratio of β phase is 0% or more and 3% or less, and β The length of each long side of the phase or γ phase is 100 μm or less.

  Note that the α phase and β phase, or the α phase and γ phase grain boundaries and phase boundaries, which are problems in corrosion resistance under harsh environments, are the phase boundaries and crystal grains that contact the β phase during high-temperature heating. By including the above-mentioned Sn, Sb, Ni including the boundary so that the composition relational expression f2 = [Sb] / [Sn] and the composition relational expression f3 = [Ni] / [Sb] are appropriate, Corrosion resistance can be improved and it can fully cope with it.

Next, a method for manufacturing a brass alloy hot-worked product according to the first and second embodiments of the present invention will be described.
First, an ingot having the above-described component composition is prepared, and hot working (hot extrusion, hot forging) is performed on the ingot. Furthermore, in this embodiment, heat treatment may be performed after hot working.

(Hot processing)
In this hot working, hot extrusion or hot forging at a temperature of 670 ° C. or more and 820 ° C. or less, and a temperature range of 620 ° C. to 450 ° C. with an average cooling rate of 2 ° C./min or more and 200 ° C./min or less. It is preferable to cool. The hot-processed material is finally brought to 100 ° C. or lower, and many are cooled to room temperature.
If the hot working temperature (hot extrusion temperature and hot forging temperature) is too high, fine cracks are generated on the surface. For this reason, the hot working temperature (hot extrusion temperature and hot forging temperature) is set to 820 ° C. or less, preferably 800 ° C. or less.
On the other hand, when the hot working temperature (hot extrusion temperature and hot forging temperature) is too low, the deformation resistance increases. Although it depends on the processing equipment capacity, for example, when manufacturing a small thin rod (diameter 12 mm or less), even if extrusion becomes difficult or even if extrusion is possible, a portion that cannot be extruded due to a temperature drop during processing occurs. The yield, which is the weight ratio of the product from the ingot, may be deteriorated. In addition, a forged product with a high degree of processing may not be sufficiently filled with material and may not be molded.

  Also, if the cooling rate after hot working is too fast, the phase change from β phase to α phase becomes insufficient, the β phase rate after cooling becomes high, and the elongated β phase tends to remain, Corrosion resistance in harsh environments is degraded. Therefore, the temperature range from 620 ° C. to 450 ° C. is cooled at an average cooling rate of 200 ° C./min or less, preferably 100 ° C./min or less. The lower limit of the cooling rate is 2 ° C./min or more in consideration of production efficiency.

Here, even when the β phase is changed from the β phase to the γ phase and the α phase during cooling, the corrosion resistance is deteriorated under a severe environment such as the γ phase is easily extended when the β phase is extended.
In particular, a hot extruded rod is obtained by extrusion from an ingot. The metal structure of the hot-extrusion rod is in a state where it is easily stretched and aligned in parallel with the extrusion direction.
On the other hand, a hot forged product is obtained by hot forging using a hot extruded material obtained by extrusion from an ingot as a raw material. In hot forging, depending on the shape of the product, the material plastically deforms and flows in various directions in the mold during hot forging, but basically it has a metal structure along the flow of the material. Hot forged material is heated and hot forged, but it is plastic because it is plastically deformed into a shape along the forging die and the metal structure of the heated hot extruded rod is destroyed. The crystal grains are hardly larger than the hot extruded material.
Since the Pb particles are hardly dissolved in the copper alloy as described above, they exist as metallic Pb particles and exist regardless of the crystal grains and the crystal grain boundaries. Therefore, Pb is in a liquid state when it is at 327 ° C. or higher, which is the melting point of Pb, during hot working or heat treatment described later. The size (average crystal grain size) and distribution (density of existing number) of the Pb particles also vary depending on the hot working temperature, the flow of the metal structure and the cooling rate. This is the same for the heat treatment described later.

(Heat treatment)
When heat treatment is performed after hot working, the heat treatment temperature is preferably 470 ° C. or more and 560 ° C. or less, and the holding time at the heat treatment temperature is preferably 1 minute or more and 8 hours or less.
In order to further improve the corrosion resistance, heat treatment is an effective means. However, when the heat treatment temperature exceeds 560 ° C., there is no effect with respect to the decrease of the β phase (phase change from the β phase to the α phase), and the β phase may increase, which causes a problem in corrosion resistance. For this reason, the upper limit of heat processing temperature is 560 degrees C or less, Preferably it is 550 degrees C or less. On the other hand, when the heat treatment temperature is less than 470 ° C., the β phase decreases, but the γ phase increases, and in some cases, the corrosion resistance may deteriorate. For this reason, the minimum of heat processing temperature is 470 degreeC or more, Preferably it is 490 degreeC or more.

Further, when the holding time at the heat treatment temperature is shorter than 1 minute, the β phase is not sufficiently reduced. On the other hand, if the holding time at the heat treatment temperature exceeds 8 hours, the effect of reducing the β phase is saturated and there is a problem in terms of energy use. Therefore, in this embodiment, the holding time at the heat treatment temperature is set to 1 minute or more and 8 hours or less.
In addition, although hot forging is performed with respect to a hot extrusion material (forging raw material), even if it heat-processes to the bar material forged, it has no big influence on forgeability. This is because the forging material is heated before hot forging, so the history of heat treatment is also cleared. However, since heat treatment is costly, generally, a brass alloy to be hot forged is often used as an extruded material (not subjected to heat treatment).

  The brass alloy hot-worked product according to the first and second embodiments is manufactured by the manufacturing method as described above.

  As described above, the brass alloy hot-worked products according to the first and second embodiments of the present invention have excellent corrosion resistance, and good hot workability and machinability. From these characteristics, it becomes a suitable material for water supply equipment such as a water faucet fitting, a joint, and a valve excellent in cost performance.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and can be appropriately changed without departing from the technical requirements 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 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.
Hereinafter, in the evaluation results, the symbol “” ”means“ excellent ”, and the symbol“ ◯ ”means“ good ”. The symbol “△” means “fair”, the symbol “×” means “poor”, and the symbol “xx” means “very poor”. .

A brass alloy hot-worked product and a billet having a composition for comparison according to the first and second embodiments of the present invention described above were produced. The composition of the copper alloy is shown in Tables 1-3.
The billet having the composition shown in Table 1 was manufactured using a commercial melting furnace and casting machine. Specifically, a molten copper alloy was melted so as to have predetermined components in a low frequency induction furnace, and a billet having a diameter of 240 mm was manufactured by a semi-continuous casting machine.
Billets having the compositions shown in Tables 2 and 3 were manufactured in a small-scale melting facility in a laboratory. Specifically, a copper alloy melt was melted so as to be a predetermined component in a small high-frequency melting furnace and cast into a mold to produce a billet having a diameter of 100 mm and a length of 125 mm.

(Hot extruded material)
Billets having the composition shown in Table 1 were cut into a diameter of 240 mm and a length of 750 mm, and extruded to a diameter of 12 mm by a 2750-ton indirect extruder. In addition, the billet was heated with the induction heating furnace before extrusion, and it was set as the extrusion temperature described in Table 4.
The cooling rate in the temperature range of 620 ° C. to 450 ° C. of the bar after extrusion was set as shown in Table 4. In addition, the temperature of the billet and the bar after extrusion was measured using a radiation thermometer.
Moreover, heat processing was implemented on the conditions shown in Table 4 with respect to the extrusion product after a hot extrusion process.

(Hot forging)
Billets having the composition shown in Table 1 were cut into a diameter of 240 mm and a length of 750 mm, and extruded to a diameter of 20 mm by a 2750-ton indirect extruder. In addition, the billet was heated with the induction heating furnace before extrusion, and it was set as the extrusion temperature described in Table 5. The cooling rate in the temperature range of 620 ° C. to 450 ° C. of the bar after extrusion was set as shown in Table 5. The bar was cooled to room temperature (20 ° C.).
The obtained hot extruded material was cut into a cylindrical shape having a diameter of 20 mm and a length of 30 mm, and a sample was collected. This sample was heated to the temperature shown in Table 5, and a columnar sample was set up with a 200-ton friction press and freely forged from a height of 30 mm to 12 mm (processing rate 60%). The cooling rate in the temperature range of 620 ° C. to 450 ° C. of the forged material was the conditions shown in Table 5. This hot forged product was also cooled to room temperature (20 ° C.).

(Lab extruded material 1)
A part of a billet having a composition shown in Table 1 having a diameter of 240 mm was cut and then the surface was cut to obtain a diameter of 95 mm and a length of 120 mm. This was used as a billet for producing the lab extrudate 1. This was heated to the temperature shown in Table 6 by a muffle furnace, and a hot extrusion rod having a diameter of 20 mm was obtained by a 200-ton direct extruder.
The cooling rate in the temperature range of 620 ° C. to 450 ° C. of the bar after extrusion was set as shown in Table 6. The extruded bar was cooled to room temperature (20 ° C.).
Moreover, heat processing was implemented on the conditions shown in Table 6 with respect to the extrusion product after a hot extrusion process.

(Lab extruded material 2)
The surface of the billet having the composition shown in Table 2 and Table 3 was cut into a diameter of 95 mm and a length of 120 mm. This was heated to the temperature shown in Table 7 and Table 8 with a muffle furnace, and a hot extrusion rod having a diameter of 20 mm was obtained with a 200-ton direct extruder.
The cooling rate in the temperature region of 620 ° C. to 450 ° C. of the bar after extrusion was set to the conditions shown in Table 7 and Table 8. The extruded bar was cooled to room temperature (20 ° C.).
Moreover, heat processing was implemented on the conditions shown in Table 7 and Table 8 with respect to the extrusion product after a hot extrusion process.

(Lab forging)
The surface of the billet having the composition shown in Table 2 and Table 3 was cut into a diameter of 95 mm and a length of 120 mm. This was heated to the temperature shown in Table 9 and Table 10 with a muffle furnace, and a hot extrusion rod having a diameter of 20 mm was obtained with a 200-ton direct extruder.
The cooling rate in the temperature region of 620 ° C. to 450 ° C. of the bar after extrusion was set to the conditions shown in Table 9 and Table 10. The extruded bar was cooled to room temperature (20 ° C.).
The obtained hot extruded material was cut into a cylindrical shape having a diameter of 20 mm and a length of 30 mm, and a sample was collected. This sample was heated to the temperature shown in Table 9 and Table 10, and a columnar sample was set up with a 200-ton friction press and freely forged from a height of 30 mm to 12 mm (processing rate 60%). The cooling rate in the temperature range of 620 ° C. to 450 ° C. of the forged material was the conditions shown in Table 9 and Table 10. The hot forged product was cooled to room temperature (20 ° C.).
Further, heat treatment was performed on the forged product after the hot forging process under the conditions shown in Table 9 and Table 10.

  The following hot workability was evaluated for the above-mentioned hot extruded material, hot forged material, laboratory extruded material, and laboratory forged material.

(Hot extrudability)
In the case of hot extruded material, the one that is 12 mm in diameter and can be extruded without leaving a portion that cannot be pushed out is marked with “◯”, and the portion that has not been pushed through is marked with “×”, and the surface of the hot extruded material is cracked. What was recognized was evaluated as “XX”. In an extrusion process that is actually performed commercially, not all ingots (billets) are extruded into bars. If everything is extruded, defects will occur at the rear end of the extruded material, which will be the end of the ingot, and it will not become a product. For this reason, the extrusion process was carried out leaving a certain amount of the ingot end portion. The length of the remaining part was set to 50 mm, and the case where an ingot exceeding 50 mm remained due to the extrusion capability of the mass production machine was evaluated as “x”.
For lab extrudates, hot extrusion rods with a diameter of 20 mm and extrusion lengths of 200 mm or more are evaluated as “◯”, and those less than 200 mm are evaluated as “x”, and the surface of the hot extrusion material is cracked. What was recognized was evaluated as “XX”.

(Hot forgeability)
A forging load of 100 tons or less was evaluated as “◯”, a forging load exceeding 100 tons was evaluated as “x”, and a forging material with cracks recognized on the surface. Evaluated as “XX”. Forgeability, “◯” evaluation is necessary. When the forging load exceeds 100 tons, it becomes difficult to forge with a forging machine with a small capacity, and there is a possibility that a forged product with a complicated shape may not be formed. .

  The above-described hot extruded material, hot forged material, lab extruded material, and lab forged material were evaluated for metal structure observation, corrosion resistance (dezincification corrosion test / immersion test), and machinability.

(Metal structure observation)
As shown in FIG. 1, the metal structure is a 1/4 portion of the diameter D in the direction parallel to the extrusion direction (if it is a φ20 mm material that is a 1/4 portion of the diameter D from the surface). The cross-sectional microstructure of the portion 5 mm from the surface, or 3 mm from the surface in the case of a φ12 mm material was observed.
As for the hot forged material, as shown in FIG. 2, the cross-sectional microstructure of a portion of 3 mm, which is ¼ of the thickness from the surface, was observed in a cross section cut in the diameter direction at a portion 8 mm outside from the center. . In hot forging, when free forging from 30 mm to 12 mm in height, a disk shape with a diameter of about 32 mm is obtained.
This observation sample was etched with a mixed etching solution of 3 vol% hydrogen peroxide water and 3 vol% ammonia water, and the metal structure was observed at a magnification of 200 times using a metal microscope (EPIPHOTO 300 manufactured by Nikon Corporation).

The area ratio of β phase and γ phase is the ratio of the area of β phase and γ phase to the total area of the observed metal structure by binarizing the observed metal structure using image processing software (WinRoof). Calculated as In addition, the area ratio enlarges the metal structure observed at a magnification of 200 times to a size of 195 mm × 243 mm (substantial magnification is 355 times), and the metal structure of an arbitrary three fields of view with an area of 75 mm × 100 mm therein Was measured and taken as the average value thereof. In each of the three visual fields, a non-overlapping portion was measured. In the binarization process, the β-phase and γ-phase portions are color-coded for the 75 mm × 100 mm portion, and the color-coded areas are measured using image processing software, and the whole (75 mm × 100 mm) is measured. The area ratio of each of the β phase and γ phase was measured.
The size and distribution (density) of the Pb particles were measured by the following method. Regarding the size of the Pb particles, the Pb particles may be fine. The metal structure was photographed at a magnification of 1000 times using a metal microscope, and the metal structure was enlarged to 195 mm × 243 mm (substantial magnification was 1775 times). In three visual fields (75 mm × 100 mm: substantial evaluation area 0.06 mm ² ) without any overlapping of the measurement visual fields, the Pb particle part is color-coded, and the color-coded area is measured using image processing software, The average particle diameter was measured from the area of the Pb particles. Specifically, assuming that the Pb particle is a circle, the diameter of the Pb particle was obtained as the particle diameter from the measured area. And the average value of the particle diameter of all the observed Pb particles was calculated | required, and it was set as the average particle diameter. The distribution (density) of Pb particles was measured as follows. The number of Pb particles was counted in three fields of view where the average particle size of the Pb particles was obtained. The number of Pb particles with respect to the entire measured location was determined, and the number per 100 μm ² (10 μm × 10 μm) was calculated. And the average value of the three places was calculated | required and it was set as distribution (density).

  The maximum length of the long side of the β phase and the γ phase was binarized with respect to the metal structure of any three fields of view using image processing software (WinRoof) in the same manner as the area ratio of the β phase and the γ phase. . Next, the absolute maximum lengths of the specified β phase and γ phase were determined. Among the absolute maximum lengths of all the measured β phases and γ phases, the largest value was taken as the maximum length. In the case of a hot extruded material, there was a maximum length in a direction parallel to the extrusion direction, and in the case of a hot forged material, there was a maximum length in a direction parallel to the material flow direction in the cross-sectional direction.

The maximum length of the long side of the β phase and the γ phase is less than 20 μm (including 0 μm, that is, the case where the β phase rate and the γ phase rate are 0%). If the length is 20 μm or more and less than 50 μm, it is the next best. When the maximum length of the long side of the β phase and γ phase is 50 μm or more and 100 μm or less, there is no problem. When the maximum length of the long side of the β phase and γ phase exceeds 100 μm, there is a problem from the viewpoint of corrosion resistance. May occur.
The β phase and the γ phase are inferior in corrosion resistance to the α phase. Corrosion resistance is enhanced by the proper addition of Sn, Sb, and Ni. However, under severe conditions, dezincification corrosion may occur in the β phase and γ phase. From the viewpoint of corrosion resistance, these phases are continuous. In other words, it is better that the length in the longitudinal direction is short, and it is desirable that the length is 100 μm or less.

(Dezincification corrosion test)
As a dezincification corrosion test, ISO65509-1 (corrosion of metals and alloys-determining of dezincification, resistance of copper alloy with zinc zinc-Part 1: Test method). That is, the surface where the cross-sectional microstructure was observed was exposed to a 1 vol% cupric chloride aqueous solution maintained at 75 ° C. (masking with an exposed area of 1 cm ² ) and immersed for 24 hours. Next, the cross-sectional microstructure was observed from the direction perpendicular to the exposed surface, and the maximum dezincification depth, which is the deepest part of the exposed surface, was measured.

The case where the maximum dezincification corrosion depth is less than 20 μm (including the case where dezincification corrosion is not observed) is evaluated as “◎”, and the case where the maximum dezincification corrosion depth is 20 μm or more and less than 50 μm is evaluated as “○ ". The case where the maximum dezincification corrosion depth was 50 μm or more and less than 100 μm was evaluated as “Δ”, and the case where the maximum dezincification corrosion depth was 100 μm or more was evaluated as “x”.
If the maximum dezincification corrosion depth is less than 100 μm, it is judged that there is dezincification corrosion resistance. Therefore, if the evaluation is “Δ” or more, it can be said that there is corrosion resistance (dezincification corrosion resistance).

(Immersion test)
Further, as a test in a severe corrosive environment, sodium hypochlorite was appropriately added to tap water, carbon dioxide gas was blown in, and a residual chlorine concentration was adjusted to 30 ppm and pH 6.8 to prepare a test solution. A test piece having an exposed surface adjusted by the same method as in the ISO 6509 test was prepared. The test piece was immersed in a test solution having a liquid temperature of 40 ° C. After 8 weeks, the test piece was taken out and the maximum dezincification corrosion depth was measured by the same method as the ISO 6509 test.

The case where the maximum dezincification corrosion depth is less than 20 μm (including the case where dezincification corrosion is not observed) is evaluated as “◎”, and the case where the maximum dezincification corrosion depth is 20 μm or more and less than 50 μm is evaluated as “○ ". The case where the maximum dezincification corrosion depth was 50 μm or more and less than 100 μm was evaluated as “Δ”, and the case where the maximum dezincification corrosion depth was 100 μm or more was evaluated as “x”.
In the immersion test, there is no standard for determining that there is clear dezincification corrosion resistance. However, if the maximum dezincification corrosion depth is less than 100 μm as in the ISO 6509 test, it was determined that there is dezincification corrosion resistance.
In any dezincification corrosion test, it goes without saying that the smaller the maximum dezincification corrosion depth, the better the corrosion resistance.

(Machinability)
A hot extruded material (no heat treatment) having a diameter of 20 mm was prepared. With a straight drill having a diameter of 3.5 mm, a hole having a depth of 10 mm was made in the center of the hot extruded material (bar material) at a rotation speed of 1250 rpm and a feed rate of 0.17 mm / rev. The torque applied to the drill at that time and the resistance value of the thrust were measured, and the cutting resistance value, which is the root mean square of the torque and thrust, was determined. Based on the cutting resistance value of JIS H3250 C3604, the machinability index was determined by the following formula, and the machinability was evaluated based on the value.
Machinability index (%) = (cutting resistance value of each brass alloy material) / (cutting resistance value of C3604) × 100
A machinability index of 90% or more was evaluated as “◎”, a machinability index of 75% or more and less than 90% was evaluated as “◯”, and a machinability index of less than 75% was evaluated as “x”. .
If the machinability index is 75% or more, it can be industrially cut without much inferior to C3604.
Further, a bar with a diameter of 20 mm and a height of 30 mm was forged to a height of 12 mm to prepare a hot forged material (no heat treatment). A test was performed with a straight drill having a diameter of 3.5 mm under the same conditions as in the case of a hot extruded material having a diameter of 20 mm, and the machinability of the hot forged material was evaluated.
Various test results are shown in Tables 11-24.

Alloy No. 1 with a Cu content of 61.2 mass% In S137 (Test No. T137), the extrudability is good, but in the extruded material, the β phase ratio is 6%, the sum of β and γ phases (β + γ) is 10%, and the maximum length of β phase or γ phase. Was 150 μm, the ratio of β phase and γ phase was high, and the maximum length of β phase or γ phase was long, so the corrosion resistance (zinc corrosion resistance) was poor.
Alloy No. 1 with a Cu content of 61.7 mass% S40 (test No. T40, T70) and alloy No. in which the Cu content was 61.8 mass%. In S52 (Test Nos. T52 and T82), there is no problem in extrudability, but the extruded material has a β phase ratio of 3 to 4%, and the total of β and γ phases (β + γ) is as high as 5%. Alternatively, the maximum length of the γ phase is relatively long as 90 to 95 μm. Corrosion resistance (zinc corrosion resistance) is also evaluated for extruded materials, forged materials, and heat-treated materials, and there is no practical problem, but the corrosion resistance is slightly lower than other alloys of the present invention.

Alloy No. 2 having a relatively high Cu content of 64.1 mass%. S6 (test No. T6, T16, T26) and alloy No. In S31 (Test Nos. T31 and T61), the extrudability and the forgeability are evaluated as “◯” and there is no problem, but the extrusion is possible with the full capacity of the extruder. The deformation resistance is large, and the extrudability is slightly deteriorated when compared with other alloys of the present invention under the same other extrusion conditions.
Alloy No. 1 having a Cu content of 64.7 mass% In S136 (Test No. T136), extrusion is not possible (there is a portion that cannot be extruded, and the extrusion length is less than 200 mm in a laboratory extruded material), which is problematic for mass production. However, the β phase and γ phase are few and the corrosion resistance is good.

Alloy No. 5 with a Pb content of 0.55 mass% In S144 (Test No. T144), other components are within the scope of the present invention, and hot workability such as extrudability and corrosion resistance are not problematic (evaluation is Δ or more), but machinability is inferior. This material has an average particle size of Pb particles of 0.1 μm, a distribution (density) of 0.001 particles / 100 μm ² , a small size, a low density, and inferior machinability (machinability).
Alloy No. 2 with a Pb content of 2.15 mass% In S145 (Test No. T145), other components are within the range, and there is no problem in hot workability, corrosion resistance, and machinability. However, if the amount of Pb is large, the amount of elution into water may increase, and a treatment for reducing the amount of elution is required. This material has an average particle diameter of Pb particles of 3.0 μm and a distribution (density) exceeding 0.06 particles / 100 μm ² , and the amount of Pb eluted increases as described above.
When the content of Pb is within the range of the present invention, the machinability evaluation is “◎” or “◯”, which is excellent. Since machinability affects not only Pb but also the structure, it cannot be evaluated only by the content of Pb, but the evaluation is “◎” for a sample that contains a large amount within an appropriate range.
The average particle diameter and distribution (density) of the Pb particles are slightly affected by the conditions of hot working (hot extrusion, hot forging) and heat treatment conditions. Alloy No. In S5, when the heat treatment temperature is as high as 580 ° C. (Test No. T5-2), the average particle diameter of Pb exceeds 3 μm, which causes a problem in the elution amount. In addition, Alloy No. Even when the hot extrusion temperature of the laboratory extruded material of S1 is as high as 850 ° C. (Test No. T21-3), the average particle diameter of Pb exceeds 3 μm. Alloy No. In S37, S44 and S45, when the hot forging temperature is as high as 840 ° C. or higher (test No. T67-3, T74-2, T75-3), surface cracking occurs, and there is a problem with hot workability, The subsequent heat treatment was not investigated. Further, when the hot forging temperature is lower than 670 ° C. in the same alloy (test Nos. T67-5, T74-3, T75-5), the deformation resistance is high and the load during hot forging exceeds 100 t. We did not investigate heat treatment. For these alloys, only the average particle size and distribution of Pb particles were investigated. As a result, Alloy No. In S37, when hot forging was performed at 850 ° C. (Test No. T67-3), the Pb average particle diameter exceeded 3 μm. No. In S44 and S45, when the hot forging temperature was 840 ° C. (Test Nos. T74-2 and T75-3), the Pb distribution was 0.001 pieces / 100 μm ² , and the machinability (machinability) was poor. In addition, Alloy No. In S44, when the hot forging temperature was as low as 650 ° C. (Test No. T74-3), the average particle diameter of Pb was 0.1 μm, and this also had poor machinability (machinability). If the average particle size and distribution of these Pb are out of the appropriate range, there will be a problem in machinability or elution of Pb. If they are in the proper range, the machinability (machinability) evaluation is satisfactory and excellent.

Alloy No. 1 with a Sn content of 0.45 mass% In S141 (test No. T141), if the other composition is within the appropriate range, there is no problem as extrudability and metal structure, but the evaluation is x in the immersion test, resulting in poor corrosion resistance.
Alloy No. 1 with Sn content of 1.10 mass% In S142 (Test No. T142), the γ phase ratio increases, and the total of β and γ phases (β + γ) exceeds 5%. Therefore, the corrosion resistance is poor, and the corrosion resistance remains poor even after heat treatment.

Although it depends on not only the content of Sn but also the content of other elements, the alloy No. 1 has an Sn content of 0.57 mass%. In S46 (Test Nos. T46 and T76), the corrosion resistance evaluation is many (determined that there is no problem in practical use), and if the Sn content is small, the corrosion resistance tends to deteriorate.
On the other hand, when the Sn content is large, the γ phase tends to increase, but there is no problem as long as it is within the scope of the present invention. Alloy No. 1 having a Sn content of 0.96 mass% In S49 (Test Nos. T49 and T79), the hot-extruded material or hot-forged material had a larger amount of γ phase, and the corrosion resistance evaluation also had more Δ.
As described above, the corrosion resistance is improved by the Sn content. However, if the Sn content exceeds the appropriate range, the γ phase increases in the metal structure, and the corrosion resistance becomes worse.

Alloy No. 1 with a Ni content of 0.018 mass% In S140 (Test No. T140), other elements are in an appropriate range, but the corrosion resistance is inferior and there is a problem.
Alloy No. 1 with a Ni content of 0.021 mass% In S41 (test Nos. T41 and T71), the compositional relational expression f3 = [Ni] / [Sb] is also low, but in the corrosion resistance evaluation, Δ is large, and in particular, the immersion test is evaluated as Δ, which is corrosion resistance. Although it was a material, the result was slightly inferior in the alloy of the present invention.
Alloy No. 1 with a Ni content of 0.11 mass%, which is higher than the range of the present invention. In S146 (Test No. T146), there is no problem in hot extrudability and corrosion resistance, but it is not preferable because the amount of Ni eluted with respect to water increases. Although depending on the content of other elements and the compositional relational expression, when the Ni content is increased, the corrosion resistance evaluation is also increased, and the corrosion resistance is improved.

Alloy No. 1 with a Sb content of 0.015 mass% Alloy No. S143 (Test No. T143) and Alloy No. in which the Sb content was 0.018 mass%. In S138 (Test No. T138), the Sb content is less than the range of the present invention, and the corrosion resistance is poor.
Alloy No. 5 with a Sb content of 0.024 mass% Alloy No. S34 (test No. T34, T64) and alloy No. having a Sb content of 0.028 mass%. In S43 (test Nos. T43 and T73), the corrosion resistance evaluation is large, and there is no practical problem with the corrosion resistance, but it can be seen that Sb affects the corrosion resistance.
On the other hand, Alloy No. with Sb content of 0.085 mass% was used. In S139 (Test No. T139), the corrosion resistance is good because the Sb content is large, but the hot workability is poor such as cracking during hot extrusion. If Sb is within the range of the present invention, the corrosion resistance is improved, although it is affected by the content of other additive elements or the compositional relational expression.

P, Mn, and Fe are unavoidable impurities, but do not significantly affect hot workability, corrosion resistance, etc., as long as they are within the ranges shown in the examples.
Alloy No. whose P content is 0.02 mass% or less. In S5 (test Nos. T5-1 to 11, T15), there was no problem in castability and hot workability (extrusion property, forgeability). On the other hand, in alloy No. S7 (test No. T7, T17) in which the P content was 0.026 mass%, cracks occurred during hot working (hot extrusion, hot forging).

Alloy No. 5 with composition relational expression f1 set to 60.32. In S101 (Test No. T101), although there is no problem in hot workability, there are many β-phases and γ-phases, and the maximum length is increased, resulting in poor corrosion resistance.
Alloy No. 5 with composition relational expression f1 set to 60.63 In S56 (Test Nos. T56 and T86), although the β and γ phases were slightly larger, the corrosion resistance evaluation was Δ.
Alloy No. with compositional relationship f1 set to 64.09 In S135 (Test No. T135), there are few β phases and γ phases and corrosion resistance is good, but there is a problem in hot workability such as cracking during extrusion.

Alloy No. with compositional relationship f1 set to 63.65 In S35 (Test Nos. T35 and T65), the β-phase and γ-phase are few and the corrosion resistance is good. As for hot workability, although the extrusion length was 200 mm or more by laboratory extrusion, it was shorter than other alloys of the present invention, and the limit of hot workability was close.
If the numerical value of the composition relational expression f1 is within an appropriate range, it is influenced by other elements, but the evaluation of corrosion resistance tends to be good. As described above, the compositional relational expression f1 relates to hot workability and corrosion resistance, and it is important for the alloy of the present invention to be within an appropriate range.

Alloy No. with composition relational expression f2 set to 0.026 In S133 (Test No. T133), the content of each element was within the appropriate range, but the corrosion resistance was poor, and the corrosion depth was large, such that the β and γ phases were preferentially dezincified. There was no problem with hot workability.
On the other hand, Alloy No. having a composition relational expression f2 of 0.132. In S134 (Test No. T134), the corrosion resistance is good, but there is a problem in hot workability such as cracking during hot extrusion.

Alloy No. with composition relational expression f2 set to 0.033 In S53 (Test Nos. T53 and T83), there is no problem in hot extrudability, and in the ISO 6509 dezincification corrosion test, ◎ evaluation is obtained with the heat treatment material. As a result, there was little improvement in corrosion resistance.
Alloy No. with composition relational expression f2 set to 0.11 S42 (test No. T42, T72), alloy No. in which the compositional relational expression f2 is 0.105. In S55 (Test Nos. T55 and T85), the corrosion resistance is relatively good, and there is no problem because the corrosion resistance evaluation becomes ◯ or more by performing the heat treatment. However, no cracks were found on the surface of the extrusion tip, but there were irregularities, and there were signs close to the limit at which cracking occurred.
In addition, if the composition relational expression f2 is within an appropriate range, the hot workability or the corrosion resistance is also good. Of course, the compositional relational expression f2 is greatly related to hot workability and corrosion resistance as described above, but each characteristic is influenced by other compositional relational expressions and additive elements.

Alloy No. with compositional relationship f3 set to 0.28 In S132 (Test No. T132), although the content of the additive element is within the appropriate range of the present application, the corrosion resistance is inferior. It is considered that the effect of Ni and Sb on the corrosion resistance is reduced because the value of the composition relational expression f3 is small.
Alloy No. with composition relational expression f3 set to 0.38 In S54 (Test Nos. T54 and T84), the corrosion resistance of the immersion test was a level at which it was possible to judge that there was corrosion resistance, although the evaluation was lower than any Δ. If the composition relational expression f3 is within an appropriate range, it is affected by the content of other elements and other compositional relational expressions, but exhibits good corrosion resistance.

  Alloy No. with compositional relationship f3 set to 3.73 In S143 (Test No. T143), the Sb content is low and the corrosion resistance is poor. Depending on the contents of Ni and Sb, if Sb is, for example, 0.03 mass%, which is the lower limit of the preferred range, [Ni] / [Sb] = 3.5 or more is the Ni content is 0.105 mass% Thus, the upper limit of the appropriate range of Ni of the present application is exceeded. Thus, when the numerical value of the relational expression f3 is large, the amount of Ni is large, and therefore there is a problem in the amount of Ni elution, or there is a possibility that Sb is low and there is a problem in corrosion resistance.

Next, test no. See T5-1 to T5-11, T12-1 to T12-8, T21-1 to T21-8, T23-1 to T23-7, T67-1 to T67-8, T75-1 to T75-6 Confirm the hot working conditions.
When the temperature conditions during hot working (hot extrusion, hot forging) are as high as 840 ° C or 850 ° C, cracks occur in the extruded material and surface cracks occur in the forged product. The performance becomes worse. In addition, Test No. Under conditions where the temperature during hot working is high, such as T21-3 and T67-3, the average particle diameter of Pb increases, and the amount of Pb elution increases, which has an adverse effect.
Conversely, when the temperature conditions during hot working (hot extrusion, hot forging) are as low as 640 ° C. or 650 ° C., extrusion is impossible (extruded length is less than 200 mm for laboratory extruded materials). ) Or the forging load is increased by forging, the deformation resistance of the material at high temperatures is increased, and the hot workability is decreased. Test No. When the hot extrusion temperature of T21-5 is as low as 640 ° C., the particle size of Pb is small and the distribution exceeds 0.06 pieces / 100 μm ^{2. In} this case, a problem occurs in the elution amount of Pb. It will be. Thus, the temperature conditions during hot working (hot extrusion, hot forging) affect not only the workability during hot working, but also the particle size and distribution of Pb.

When the cooling rate in the temperature range from 620 ° C. to 450 ° C. exceeds 200 ° C./min after hot working (hot extrusion, hot forging) (test No. T5-11, T21-7), Corrosion resistance is poor due to many β phases and long maximum length.
On the other hand, when the above cooling rate is lower than 2 ° C./min, it is not carried out. However, if it is 1 ° C./min, for example, the cooling time is 170 minutes, which causes problems in mass productivity.

Next, test no. The heat treatment conditions will be confirmed with reference to T5-1 to T5-10 and T12-1 to T12-7.
When the heat treatment conditions of the hot extruded material and the hot forged product exceed 560 ° C., the β phase is large, the maximum length is long, and the corrosion resistance is poor.
When the conditions for heat treatment of the hot extruded material and the hot forged product are less than 470 ° C., the γ phase increases more than the other conditions, the maximum length is longer, and the corrosion resistance becomes worse.
The holding time is the same as the extrusion under the condition of less than 1 minute, and the effect of heat treatment is not seen. On the other hand, even if it exceeds 8 hours (480 minutes), there is no significant difference from the conditions within 8 hours, and only the cost for heat treatment is required.

  As described above, the alloy of the present invention in which the content of each additive element and each compositional relational expression are in an appropriate range are excellent in hot workability (hot extrusion, hot forging), and have good corrosion resistance and machinability. Moreover, in order to obtain the outstanding characteristic in this invention alloy, it can achieve by making the manufacturing conditions in hot extrusion and hot forging, and the conditions in heat processing into an appropriate range.

  The brass alloy hot-worked product of the present invention is excellent in hot workability (hot extrudability and hot forgeability), and excellent in corrosion resistance and machinability. For this reason, the brass alloy hot-worked product of the present invention can be suitably applied as a component for water supply equipment such as a water faucet fitting, a joint, and a valve.

The present invention has been made on the basis of such knowledge, and the brass alloy hot-worked product according to the first aspect of the present invention has Cu: 61.5 mass% or more and 64.5 mass% or less, Pb: 0.0. 6 mass% or more and 2.0 mass% or less, Sn: 0.55 mass% or more and 1.0 mass% or less, Sb: 0.02 mass% or more and 0.08 mass% or less, Ni: 0.02 mass% or more and 0.10 mass% or less The balance is made of Zn and inevitable impurities, the content of P, which is an inevitable impurity, is 0.02 mass% or less, the Cu content is [Cu] mass%, the Pb content is [Pb] mass%, Sn When the content of [Sn] mass%, the content of Sb is [Sb] mass%, and the content of Ni is [Ni] mass%,
60.5 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 64.0,
0.03 ≦ [Sb] / [Sn] ≦ 0.12,
0.3 ≦ [Ni] / [Sb] ≦ 3.5,
And the metal structure is an α phase matrix, includes Pb particles, the total area ratio of the β phase area ratio and the γ phase area ratio is 0% or more and 5% or less, and the β phase or γ The long side length of each phase is 100 μm or less .

The brass alloy hot-worked product according to the second aspect of the present invention is Cu: 62.0 mass% or more and 64.0 mass% or less, Pb: 0.7 mass% or more and 2.0 mass% or less, Sn: 0.60 mass% or more 0.95 mass% or less, Sb: 0.03 mass% or more and 0.07 mass% or less, Ni: 0.025 mass% or more and 0.095 mass% or less, with the balance being Zn and inevitable impurities, and P being an inevitable impurity The content is 0.02 mass% or less, the Cu content is [Cu] mass%, the Pb content is [Pb] mass%, the Sn content is [Sn] mass%, and the Sb content is [ Sb] mass%, when the content of Ni is [Ni] mass%,
60.7 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 63.6,
0.035 ≦ [Sb] / [Sn] ≦ 0.10,
0.4 ≦ [Ni] / [Sb] ≦ 3.5,
And the metal structure is an α phase matrix, includes Pb particles, the total area ratio of the β phase area ratio and the γ phase area ratio is 0% or more and 5% or less, and the β phase or γ The long side length of each phase is 100 μm or less .

The brass alloy hot-worked product according to the third aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and the average particle size of the Pb particles is 0. .2 μm or more and 3 μm or less.

The brass alloy hot-worked product according to the fourth aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, contains Pb particles, and the distribution of Pb particles is 0.002. It is characterized by the number of pieces / 100 μm ² or more and 0.06 pieces / 100 μm ² or less.

The brass alloy hot-worked product according to the fifth aspect of the present invention is the above-described brass alloy hot-worked product, wherein the metal structure is an α-phase matrix, includes Pb particles, and the average particle size of the Pb particles is 0. .2μm or more and 3μm or less, and the distribution of Pb particle 0.002 / 100 [mu] m ² or more, characterized in that 0.06 units / 100 [mu] m ² or less.

The brass alloy hot-worked product according to the sixth aspect of the present invention is the above-described brass alloy hot-worked product, and is characterized by being used as a water supply device.

The method for manufacturing a brass alloy hot-worked product according to the seventh aspect of the present invention is a method for manufacturing a brass alloy hot-worked product for manufacturing the above-described brass alloy hot-worked product, and is 670 ° C. or higher and 820 ° C. or lower. And a temperature region from 620 ° C. to 450 ° C. is cooled at an average cooling rate of 200 ° C./min or less.

A method for manufacturing a brass alloy hot-worked product according to an eighth aspect of the present invention is the above-described method for manufacturing a brass alloy hot-worked product, wherein the hot-working product has a temperature of 470 ° C. or higher and 560 ° C. or lower. It is characterized by performing a heat treatment for holding for 8 minutes or more.

Claims (10)

Cu: 61.5 mass% to 64.5 mass%, Pb: 0.6 mass% to 2.0 mass%, Sn: 0.55 mass% to 1.0 mass%, Sb: 0.02 mass% to 0.08 mass% Hereinafter, Ni: 0.02 mass% or more and 0.10 mass% or less, the balance consists of Zn and inevitable impurities,
The Cu content is [Cu] mass%, the Pb content is [Pb] mass%, the Sn content is [Sn] mass%, the Sb content is [Sb] mass%, and the Ni content is [ Ni] mass%,
60.5 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 64.0,
0.03 ≦ [Sb] / [Sn] ≦ 0.12,
0.3 ≦ [Ni] / [Sb] ≦ 3.5,
A brass alloy hot-worked product characterized by satisfying Cu: 62.0 mass% to 64.0 mass%, Pb: 0.7 mass% to 2.0 mass%, Sn: 0.60 mass% to 0.95 mass%, Sb: 0.03 mass% to 0.07 mass% Hereinafter, Ni: 0.025 mass% or more and 0.095 mass% or less, the balance is made of Zn and inevitable impurities,
The Cu content is [Cu] mass%, the Pb content is [Pb] mass%, the Sn content is [Sn] mass%, the Sb content is [Sb] mass%, and the Ni content is [ Ni] mass%,
60.7 ≦ [Cu] + 0.5 × [Pb] −2 × [Sn] −2 × [Sb] + [Ni] ≦ 63.6,
0.035 ≦ [Sb] / [Sn] ≦ 0.10,
0.4 ≦ [Ni] / [Sb] ≦ 3.5,
A brass alloy hot-worked product characterized by satisfying   The metal structure is an α phase matrix, contains Pb particles, and the total area ratio of the β phase area ratio and the γ phase area ratio is 0% or more and 5% or less. The brass alloy hot-worked product according to claim 2.   The metal structure is an α phase matrix, contains Pb particles, and the length of each long side of the β phase or the γ phase is 100 μm or less. 5. The brass alloy hot-worked product described in 1.   5. The metal structure is an α-phase matrix, contains Pb particles, and the Pb particles have an average particle size of 0.2 μm or more and 3 μm or less. 6. Brass alloy hot-worked products. Metal structure is α phase matrix comprises a Pb particles, distribution of Pb particle 0.002 / 100 [mu] m ² or more, claim from claim 1, characterized in that 0.06 units / 100 [mu] m ² or less The brass alloy hot-worked product according to any one of 4. The metal structure is an α-phase matrix, contains Pb particles, the average particle size of the Pb particles is 0.2 μm or more and 3 μm or less, and the distribution of Pb particles is 0.002 particles / 100 μm ² or more, 0.06 The brass alloy hot-worked product according to any one of claims 1 to 4, wherein the number is 100 pieces / 100 μm ² or less.   The brass alloy hot-worked product according to any one of claims 1 to 7, which is used as a water supply device. A method for producing a brass alloy hot-worked product for producing the brass alloy hot-worked product according to any one of claims 1 to 7,
Hot-working at a temperature of 670 ° C. or more and 820 ° C. or less, and cooling a temperature region from 620 ° C. to 450 ° C. at an average cooling rate of 200 ° C./min or less. Method.   The method for manufacturing a brass alloy hot-worked product according to claim 9, wherein after the hot working, heat treatment is performed at a temperature of 470 ° C to 560 ° C for 1 minute to 8 hours.

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