KR101929170B1 - Brass alloy hot-worked article and method for producing brass alloy hot-worked article - Google Patents

Abstract

One aspect of the brass alloy hot-rolled product is a copper alloy product comprising 61.5 to 64.5 mass% of Cu, 0.6 to 2.0 mass% of Pb, 0.5 to 1.0 mass% of Sn, 0.02 to 0.08 mass% of Sb and 0.02 to 0.10 mass% of Ni And the remainder is composed of Zn and inevitable impurities, and the following expression is satisfied.
60.5? [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]? 64.0
0.03? [Sb] / [Sn]? 0.12
0.3? [Ni] / [Sb]? 3.5

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a brass alloy hot work and a brass alloy hot work,

[0001]

The present invention relates to a brass alloy hot work product (hot work product of a brass alloy) excellent in corrosion resistance, and a method of manufacturing the brass alloy hot work product.

The present application claims priority based on Japanese Patent Application No. 2016-104136 filed on May 25, 2016, the contents of which are incorporated herein by reference.

[0002]

JIS H3250 C3604 (Free-cutting brass) or C3771 (Brass for forging) is mainly used as the above-mentioned brass alloy hot working material (hot extruded bar or hot forging) because of excellent machinability (cutting ability) or mono-composition.

However, since these brass alloy materials contain a large amount of beta phase which is composed of alpha phase and beta phase and which is poor in corrosion resistance, these brass alloy materials are used under corrosive environments in which they come in contact with tap water such as faucets, Zinc corrosion occurs easily, and corrosion such as leakage occurs over time.

[0003]

Here, there is a case where a γ-phase of 5% or more in area ratio is precipitated for the purpose of improving the internal zinc corrosion resistance of the brass alloy material. Patent Document 1 discloses an internal zinc brass bonding member containing 1.5 mass% or more of Sn in the? Phase. Patent Document 2 discloses a copper alloy having a composition of 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% Materials having improved zinc corrosion resistance have been proposed.

[0004]

The alloy disclosed in Patent Document 1 is an alloy containing a large amount of hard and brittle γ phase and has a problem that cracks are likely to occur when a sudden force is applied, for example, in a water hammer phenomenon in an electric power receiver. Also, since the? -Phase is superior to the? -Phase but has a higher internal-zinc corrosion resistance than the? -Phase, when there is a large amount of the? -Phase, dezinc corrosion preferentially occurs on the? -Phase.

On the other hand, the copper-based alloy disclosed in Patent Document 2 is inferior in substantial antireflective zinc corrosion resistance because it does not contain Sn, and if it contains a large amount of P, there is also a manufacturing problem such as cracking during casting .

[0005] Patent Document 1: JP-A-2002-069552 Patent Document 2: JP-A-11-131158

[0006]

It is an object of the present invention to provide a method for manufacturing a brass alloy hot work product and a brass alloy hot work product excellent in corrosion resistance such as internal zinc corrosion and excellent in hot workability.

[0007]

The first aspect of the present invention is a brass alloy hot-work product, which comprises 61.5 mass% or more and 64.5 mass% or less of Cu, 0.6 mass% or more and 2.0 mass% or less of Pb, 0.55 , Cu: 0.02 to 0.08 mass%, Ni: 0.02 to 0.10 mass%, the balance being Zn and inevitable impurities, Cu content being [Cu] the mass% of Sn, the mass% of Sb, the mass% of Sn, and the mass percentage of Ni, respectively, of the mass%, Pb,

60.5? [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]? 64.0,

0.03? [Sb] / [Sn]? 0.12,

0.3? [Ni] / [Sb]? 3.5.

[0008]

The second aspect of the present invention is a brass alloy hot-work product, which comprises 62.0 to 64.0% by mass of Cu, 0.7 to 2.0% by mass of Pb, 0.70 to 0.95% by mass of Sn, By mass or more and 0.08% by mass or more and 0.025% by mass or less, and the remainder being Zn and inevitable impurities, the content of Cu being [Cu] mass%, the content of Pb being [Pb] , The content of Sn is [Sn] mass%, the content of Sb is [mass%] and the content of Ni is [Ni] mass%

60.7? [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]? 63.6,

0.035? [Sb] / [Sn]? 0.10,

0.4? [Ni] / [Sb]? 3.5.

[0009]

The brass alloy hot work product of the third aspect of the present invention is characterized in that in the above-mentioned brass alloy hot work product, the metal structure is an a-phase matrix and contains Pb particles, and the area ratio of the sum of the area ratio of? Is not less than 0% and not more than 5%.

[0010]

The brass alloy hot work product of the fourth aspect of the present invention is a brass alloy hot work product wherein the metal structure is an a-phase matrix and contains Pb particles and the length of each long side of the? Phase or? Phase is 100 占 퐉 or less .

[0011]

The brass alloy hot work product of the fifth aspect of the present invention is characterized in that in the above-mentioned brass alloy hot work product, the metal structure is an a-phase matrix and contains Pb particles, and the average particle size of Pb particles is 0.2 탆 or more and 3 탆 or less .

[0012]

In a sixth aspect of brass alloy brass alloy hot foods hot-processed products is described in the present invention and having a metal structure α-phase matrix, comprising a Pb particles, the distribution of Pb particle 0.002 pieces / 100μm ² or more, 0.06 Dog / 100 μm ² or less.

[0013]

The brass alloy hot work product of the seventh aspect of the present invention is characterized in that in the above-mentioned brass alloy hot work product, the metal structure is an a-phase matrix and contains Pb particles, wherein the average particle size of the Pb particles is 0.2 탆 or more, And the distribution of the Pb particles is 0.002 / 100 μm ² or more and 0.06 / 100 μm ² or less.

[0014]

The brass alloy hot work product of the eighth aspect of the present invention is the brass alloy hot work product described above and is characterized by being used as a water service tool.

[0015]

A ninth aspect of the present invention is a method for producing a brass alloy hot work product for producing the above-mentioned brass alloy hot work product, which comprises hot working at a temperature of 670 캜 to 820 캜, And the temperature range up to 450 占 폚 is cooled at an average cooling rate of 200 占 폚 / min or less.

[0016]

A tenth aspect of the present invention is a method for producing a brass alloy hot-worked article, characterized in that, in the above-described method for producing a brass alloy hot work product, after the hot working, a temperature of 470 DEG C to 560 DEG C for 1 minute to 8 hours And a heat treatment for maintaining the heat treatment is performed.

[0017]

According to the aspect of the present invention, it is possible to provide a method of manufacturing a brass alloy hot work product and a brass alloy hot work product excellent in corrosion resistance such as internal zinc corrosion and excellent in hot workability.

[0018]
BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory view showing a metal structure observation position of the hot extruded material in the examples. Fig.
Fig. 2 is an explanatory view showing a metal structure observation position of the hot forging material in the embodiment. Fig.

[0019]

Hereinafter, a method of manufacturing a brass alloy hot work product and a brass alloy hot work product according to an embodiment of the present invention will be described.

The brass alloy hot work product of the present embodiment is used as a water supply mechanism such as a water supply power fitting, a joint, and a valve. The brass alloy hot working product of the present embodiment is a brass alloy hot extruded rod or a brass alloy hot forging product.

[0020]

Here, in this specification, an element symbol enclosed in parentheses, such as [Zn], represents the content (mass%) of the element.

In the present embodiment, a plurality of compositional relationship expressions are defined as follows using the display method of the content.

The compositional relationship f1 = [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]

Composition relation f2 = [Sb] / [Sn]

Composition relation f3 = [Ni] / [Sb]

[0021]

The brass alloy hot work product according to the first embodiment of the present invention is a brass alloy hot work product comprising 61.5 to 64.5 mass% of Cu, 0.6 to 2.0 mass% of Pb, 0.5 to less than 1.0 mass% of Sn, 0.02 to 0.08% by mass, Ni: 0.02 to 0.10% by mass, and the balance of Zn and inevitable impurities, wherein the compositional relationship f1 is in the range of 60.5? F1? 64.0, 0.03? F2? 0.12, and the compositional relationship f3 is within a range of 0.3? F3? 3.5.

[0022]

The brass alloy hot work product according to the second embodiment of the present invention is a brass alloy hot work product comprising 62.0 to 64.0 mass% of Cu, 0.7 to 2.0 mass% of Pb, 0.60 to 0.95 mass% of Sn, 0.03 to 0.07% by mass, Ni: 0.025 to 0.095% by mass, and the balance of Zn and inevitable impurities, wherein the compositional relationship f1 is in the range of 60.7? F1? 63.6, The compositional relationship formula f3 is in the range of 0.4? F3? 3.5 in the range of 0.035? F2?

[0023]

In the above-mentioned brass alloy hot work products according to the first and second embodiments of the present invention, the metal structure is an a-phase matrix and includes Pb particles, and the area ratio of the total area ratio of the? Is not less than 0% and not more than 5%.

The length of each of the long sides of the? Phase or? Phase is 100 占 퐉 or less.

[0024]

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

[0025]

(Cu)

Cu is a main element constituting the alloy of the present invention and is greatly influenced by the relationship with Sn, Pb and Zn. However, in the hot extruded material and hot forging, which are hot working materials of the alloy of the present invention, excellent corrosion resistance, , Cu is required to be at least 61.5 mass%, and preferably at least 62.0 mass%. On the other hand, when the content of Cu exceeds 64.5 mass%, the ratio of the? Phase or the like which lowers the deformation resistance during hot working, that is, hot extrusion and hot forging, becomes low. As a result, the deformation resistance in the hot state becomes large, and the hot working temperature for proper hot working becomes high. In addition, not only the hot extrudability and the hot hardness which are hot working are deteriorated but also the cutting ability is deteriorated, the strength is lowered, and the corrosion resistance is also saturated. Due to this, the upper limit of the content of Cu is 64.5% by mass or less, preferably 64.0% by mass or less.

[0026]

(Pb)

Pb is contained in order to improve machinability (machinability). For this purpose, Pb is required to be 0.6 mass% or more. Or more, preferably 0.7 mass% or more, and particularly 1.0 mass% or more when cutting property is required. As the content of Pb increases, machinability is improved. On the other hand, when Pb is contained in an amount exceeding 2.0 mass%, the elution amount with respect to water increases, and the environmental load may increase. Therefore, the upper limit of the content of Pb is 2.0 mass% or less.

Pb is present as Pb particles since most of the Pb is not solid-dissolved in the mother 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 are small in size and uniformly distributed at a high density. On the other hand, with respect to the elution amount of Pb, the larger the area of the Pb particles in contact with the aqueous solution such as tap water or the like to be contacted, the larger the amount of elution becomes, so that the size and distribution of the Pb particles are opposite to the machinability (machinability). Therefore, in order to balance the machinability (machinability) and the elution amount required for the alloy of the present invention, there is a suitable range for each of the size and distribution of the Pb particles. For machinability (machinability), the average particle size of the Pb particles is required to be not less than 0.2 탆 and not more than 3 탆. When the average particle size of the Pb particles exceeds 3 탆, the Pb particles are stretched on the cutting face at the time of cutting, but the area of the Pb is increased. As a result, the area of Pb in contact with tap water becomes larger and the amount of Pb leached increases. When the average particle diameter is less than 0.2 mu m, the particles are small and do not serve as a chip breaker for improving cutting performance.

Distribution of Pb particle indicates the presence the number (density) of the particles per cross-sectional area Pb 100μm ^2. If the distribution (density) of Pb particles is 0.002 / 100 μm ² or more and 0.06 / 100 μm ² or less, it contributes to cutting performance (machinability). If the distribution of the Pb particles is less than 0.002 / 100 mu m < ^{2 &} gt ;, the presence of the Pb particles is small and does not serve as a chip breaker and the machinability index is lowered (less than 75%).

The distribution of the Pb particles is advantageous in terms of machinability (machinability), but is preferably smaller in view of the elution of Pb. Pb particles are substantially dissolved on the cutting surface due to elongation in the direction in which the cutting tool is moved, for example, when the cutting tool is brought into contact with the cutting tool and partially dissolved by the heat generated at that time. Therefore, if the distribution of the Pb particles is large, Pb present on the surface after cutting necessarily increases, and the amount of Pb elution necessarily becomes large. When the leaching amount (elution amount) of Pb is measured by JIS S3200-7 (the apparatus for leaching performance test), even when the capacity is corrected, the average particle diameter of the Pb particles exceeds 3 μm And the distribution of the particles exceeds 0.06 / 100 μm ² . In addition, 0.007 mg / L of lead leaching amount (leaching amount) is the upper limit of the reference value of leaching solution in the terminal water supply described in No. 15 of the Ministry of Health, Labor and Welfare, the main component being copper alloy, Is not available as a terminal water supply.

Therefore, the upper limit of the distribution (density) of the Pb particles is set to 0.06 / 100 μm ² or less which does not cause problems in the amount of elution (amount of leaching).

In view of the above, the average particle size of the Pb particles is 0.2 to ³占 퐉, and the distribution is 0.002 to 0.06 / 100 占 퐉 ² .

[0027]

(Sn)

Sn is greatly influenced by the relationship with Cu and Zn, but improves the corrosion resistance, particularly the internal zinc corrosion resistance, in a severe water quality in the copper alloy. Sn also lowers deformation resistance in hot working, that is, hot extrusion, and hot in hot forging. In order to achieve this, 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, when Sn is contained in an amount exceeding 1.0 mass%, the ratio of the? -Phase or the? -Phase becomes large, and the corrosion resistance becomes rather problematic. As a result, the upper limit of the content of Sn is 1.0 mass% or less, preferably 0.95 mass% or less.

[0028]

(Sb)

Sb has an effect of improving the corrosion resistance in severe water quality, particularly the internal zinc corrosion resistance, in the copper alloy, and further exerts its effect under the co-addition of Sn and Ni. In order to exhibit excellent corrosion resistance, Sb is required to be not less than 0.02 mass%, preferably not less than 0.03 mass%, and more preferably not less than 0.035 mass%. On the other hand, even if Sb is contained in an amount exceeding 0.08 mass%, the effect not only saturates but also adversely affects the workability in hot and deteriorates the workability in cold. Therefore, the upper limit of the content of Sb is 0.08 mass% or less, preferably 0.07 mass% or less, and more preferably 0.065 mass% or less.

[0029]

(Ni)

Ni has an action of enhancing the corrosion resistance and the internal zinc corrosion resistance in the severe water quality and particularly the effect of Sb in the copper alloy under the coexistence with Sn and Sb. In order to exhibit excellent corrosion resistance, Ni is required to be not less than 0.02 mass%, preferably not less than 0.025 mass%. On the other hand, when Ni is contained in an amount exceeding 0.10% by mass, there is a fear that the elution amount of Ni is increased under severe water quality. Therefore, the upper limit of the content of Ni is 0.10% by mass or less, preferably 0.095% by mass or less.

[0030]

(Inevitable impurities)

Pb-containing copper alloys are used as main raw materials in terms of recycling and cost in terms of cutting debris and waste products. Several kinds of elements such as Fe are mixed with the cutting debris by, for example, tool abrasion or the like. The waste product may be plated with Cr or the like. Since they are used as raw materials, inevitable impurities are incorporated more than other copper alloys. For example, regarding the amount of Fe treated as impurities, in the copper alloy (C3604) containing about 3 mass% of Pb and the copper alloy (C3605) containing about 4 mass% of Pb, which are defined by JIS H 3250, 0.5% by 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 properties do not significantly affect the properties.

P, like Sb, acts to improve the corrosion resistance of the copper alloy. However, if P is mixed even in a small amount, cracks tend to be generated on the surface or inside of the ingot at the time of ingot formation, and cracks easily occur on the surface of the material during hot working. However, if the content of P is more than 0.02 mass%, for example, problems occur in forming the ingot and problems in hot working. Therefore, even if P is incorporated, The upper limit value is preferably 0.02 mass% or less.

[0031]

(Compositional relation f1)

In order to exhibit excellent corrosion resistance and to ensure good hot workability, it is not sufficient to specify the content range of each element such as Cu, Sn, and Ni. The Cu content is set to [Cu] mass%, the Pb content to [Pb] mass%, the Sn content to the [Sn] mass%, the Sb content to the [Sb] mass% and the Ni content to the [Ni] When the value of the compositional relationship f1 = [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni] is less than 60.5, good corrosion resistance can not be obtained. Further, in the step after hot working (hot extrusion, hot forging), excellent corrosion resistance can not be exerted even when heat treatment is carried out.

Therefore, the lower limit of the compositional relationship formula f1 is 60.5 or more, preferably 60.7 or more, and more preferably 61.0 or more.

On the other hand, when the value of the compositional relationship f1 = [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni] exceeds 64.0, the deformation resistance in the hot state becomes higher, The heat resistance, and the hot workability, that is, the hot extrudability and the hot step composition can not be ensured. For example, good hot workability means that the hot extrusion does not have cracks on the surface of the extruded rod, and that it is possible to extrude the extruded rod with a minimum dimension of 12 mm in practical use, though it depends on the hot working temperature and the facility capability . Regarding hot forging, whether the surface of the forged product does not cause cracking and whether thin forging is possible.

Therefore, the upper limit of the compositional relationship formula f1 is 64.0 or less, preferably 63.6 or less, and more preferably 63.0 or less.

[0032]

(Compositional relationship f2)

Only when Sb and Sn are contained in predetermined amounts, particularly excellent corrosion resistance and anti-slag corrosion resistance can not be obtained. Both the Sn and Sb elements are solved more than the α phase of the matrix at a stable β phase at a high temperature of 600 ° C. or higher. Alternatively, Sn and Sb are solved more than the α phase of the matrix at a stable γ phase at 475 ° C. or lower, particularly 450 ° C. or lower. The amount of Sn and Sb solved in the? Phase differs depending on the ratio of the? Phase of the matrix and the? Phase and / or the? Phase. , About two to seven times more. Further, the amount of Sn and Sb to be solved in the? -Phase is solved by about 7 to 15 times as much as that in the? -Phase. First, in order to make the α-phase of the matrix superior in corrosion resistance, the presence ratio of Sb and Sn is important, and Sb and Sn are in the above composition. When the compositional relationship f2 = [Sb] / [Sn] is 0.03? F2? 0.12, the effect of the co-addition of Sn and Sb becomes more significant and the corrosion resistance of the α phase is most improved. Preferably, the lower limit of the compositional relationship formula f2 is 0.035 or more, and the upper limit of the compositional relationship formula f2 is 0.10 or less.

[0033]

It is difficult to make the β phase of the Cu-Zn-Sn alloy particularly excellent in corrosion resistance, but the compositional relationship f2 = [Sb] / [Sn] satisfies 0.03 ≦ f2, preferably 0.035 ≦ f2 , The corrosion resistance of the β phase is improved and the corrosion resistance of the extruded material or the forgings is improved. The alloy of the present invention increases the hot workability by producing a? Phase having a low thermal deformation resistance at a high temperature. However, the? Phase is phase-changed to the? Phase and the corrosion resistance is increased as the temperature is lowered. However, there is a problem in the grain boundary system and the phase change system that the phase changes from the? Phase to? Phase. When the value of the compositional relationship f2 = [Sb] / [Sn] is at least 0.03 or more and 0.12 or less, the corrosion resistance of the grain boundary system and the marginal system increases.

When the temperature is lower than or equal to 475 ° C or lower than or equal to 450 ° C, when the β phase changes to the α phase, the concentration of Sn and Sb solidified in the β phase becomes higher, and a γ phase is generated. When 0.03 ≤ f2 ≤ 0.12, the corrosion resistance of the alpha phase and the gamma phase grain boundary system, grain boundary phase and gamma phase itself is further improved.

When the compositional relation f2 = [Sb] / [Sn] exceeds 0.12, the amount of Sb is excessively larger than that of Sn and the deformability in the heat of the? Phase and the? Phase is lowered, .

[0034]

(Compositional relation f3)

Like the composition relation f2 = [Sb] / [Sn], the relationship between Ni and Sb is also important. Depending on the presence of Ni, the effect of Sb is higher with respect to the corrosion resistance of the alpha phase and the gamma phase of the matrix, and the corrosion resistance of the beta phase also increases. Particularly, it improves the grain boundary system when the state is changed from the stable? Phase to the? Phase at high temperature, the crystal system, and the phase system and? Phase corrosion resistance when the state changes from the? Phase to? Phase and the? Phase at the low temperature side. In order to exert their effect, the value of the compositional relationship f3 = [Ni] / [Sb] is 0.3 or more, and 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 the value of the compositional relationship f3 = [Ni] / [Sb] is set to 3.5 or less in consideration of saturation of the above effect.

[0035]

(Metal structure)

In order to ensure good hot workability, it is essential that the? Phase exists at the hot working temperature. The? -Phase generated at the high-temperature heating temperature or the working temperature changes to? -Phase or? -Phase with the temperature drop. Although depending on the manufacturing process, the? -Phase with a problem of corrosion resistance remains even in the composition of the present invention alloy, and a? Phase is sometimes generated. Since the corrosion resistance of the β phase and the γ phase is improved by containing Sn, Sb and Ni in such a manner that the composition relation f2 = [Sb] / [Sn] and the compositional relation f3 = [Ni] / [ , It is not a problem in general water quality, but it can not be said to be sufficient under harsh environments.

[0036]

That is, the sum of the ratios of the? -Phase and the? -Phase contained in the metal structure exceeds 5% at the area ratio, and the length of each of the? -Phase or? -Phase in the? When it exceeds 100 탆, it can not withstand corrosion resistance under harsh environments. Since the internal-alkali corrosion resistance of the? phase or? phase is lower than that of the? phase, when they are present in the metal structure, they may preferentially exhibit dezinc corrosion. That is, when the length of the long side exceeds 100 袖 m, the dezinc corrosion depth may exceed 100 袖 m, which causes a problem in corrosion resistance. Therefore, it is necessary that the sum of the ratios of the? -Phase and the? -Phase contained in the metal structure is 0% or more and 5% or less in the area ratio or the length of each long side of the? Or? Phase is 100 占 퐉 or less. When the sum of the ratios of the β phase and the γ phase is 0% or more and 5% or less in terms of the area ratio, the β phase area ratio is preferably 0% or more and 3% or less. More preferably, the sum of the ratios of the? -Phase and the? -Phase contained in the metal structure is 5% or less of the area ratio and the length of each of the? -Phase or? -Phase is 100 占 퐉 or less. It is best that the sum of the ratios of the β phase and the γ phase is 0% or more and 5% or less in the area ratio and the area ratio of the β phase is 0% or more and 3% or less, The length of each long side is 100 μm or less.

[0037]

In addition, the grain boundary system and grain boundary system of α-phase and β-phase, α-phase and γ-phase, which are problematic in corrosion resistance under harsh environments, include a grain boundary system and a grain boundary system with α- Sb and Ni are contained in such a manner that the compositional relationship f2 = [Sb] / [Sn] and the compositional relationship f3 = [Ni] / [Sb] become appropriate, so that corrosion resistance can be improved and sufficient countermeasures can be achieved.

[0038]

Next, a method of manufacturing a brass alloy hot work product according to the first and second embodiments of the present invention will be described.

First, an ingot having the above-described composition is prepared and subjected to hot working (hot extrusion and hot forging) on the ingot. In the present embodiment, heat treatment may be performed after hot working.

[0039]

(Hot working)

In this hot working, the hot extrusion or hot forging at a temperature of 670 ° C or higher and 820 ° C or lower and cooling the temperature region of 620 ° C to 450 ° C at an average cooling rate of 2 ° C / minute to 200 ° C / minute or less desirable. The material after the hot working is ultimately set to 100 ° C or less, and most of the material is cooled to room temperature.

If the hot working temperature (hot extrusion temperature and hot forging temperature) is too high, fine cracks will occur on the surface. For this reason, the hot working temperature (hot extrusion temperature and hot forging temperature) is 820 DEG C or lower, preferably 800 DEG C or lower.

On the other hand, if the hot working temperature (hot extrusion temperature and hot forging temperature) is too low, the deformation resistance becomes high. For example, when a thin rod (diameter of 12 mm or less) having a small size is produced, it is difficult to extrude or extruded, a portion that can not be extruded due to temperature drop occurs during processing, There is a possibility that the yield, which is the weight ratio of the product, is deteriorated. Further, in a forged product having a high degree of processing, there is a fear that the material can not be sufficiently charged and therefore can not be molded.

[0040]

If the cooling rate after the hot working is excessively high, the phase change from the? Phase to the? Phase becomes insufficient, the? Phase rate after cooling becomes high, the elongated? Phase tends to remain, and the corrosion resistance in a harsh environment deteriorates. For this reason, the temperature range from 620 ° C to 450 ° C is to be 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 set at 2 ° C / min or more in consideration of the production efficiency.

[0041]

Here, even when the phase changes into the? -Phase and the? -Phase during the cooling, when the? -Phase is elongated, the? -Phase also tends to elongate, so that the corrosion resistance is deteriorated under a harsh environment.

In particular, hot extruded bars are obtained by extrusion from ingot. The metal structure of the hot extruded rod is arranged in parallel with the extrusion direction, and is in a situation where it is easy to elongate.

On the other hand, a hot forging product is obtained by hot forging 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 in various directions in the mold, but it basically becomes a metal structure along the flow of the material. Since the hot extruded material is heated and forged, but the metal structure of the heated hot extruded rod is destroyed, the crystal grains are hardly larger than the hot extruded material as a material in general.

Since the Pb particles are mostly not solved in the copper alloy as described above, they exist as Pb particles of the metal, and exist in the crystal grain and in the grain boundaries. Therefore, during the hot working or in the heat treatment described later, when the melting point of Pb is 327 占 폚 or higher, Pb is in a liquid state. The size (average crystal grain size) and distribution (density of the existing number) of the Pb particles vary with the temperature of the hot working, the flow of the metal structure and the cooling rate. This is the same in the heat treatment to be described later.

[0042]

(Heat treatment)

In the case of performing the heat treatment after the hot working, it is preferable that the heat treatment temperature is 470 DEG C or higher and 560 DEG C or lower, and the holding time at the heat treatment temperature is 1 minute or more and 8 hours or less.

In order to enhance the corrosion resistance, heat treatment is effective. However, when the heat treatment temperature exceeds 560 DEG C, there is no effect on the reduction of the? Phase (phase change to? Phase), and the? Phase may be rather increased, resulting in corrosion resistance. Due to this, the upper limit of the heat treatment temperature is 560 캜 or lower, preferably 550 캜 or lower. On the other hand, when the heat treatment is performed at a temperature lower than 470 캜, the? Phase is decreased, but the? Phase is increased, and in some cases, the corrosion resistance is sometimes deteriorated. Due to this, the lower limit of the heat treatment temperature is 470 DEG C or higher, preferably 490 DEG C or higher.

[0043]

When the holding time at the heat treatment temperature is shorter than 1 minute, the? Phase does not decrease sufficiently. On the other hand, if the holding time at the heat treatment temperature exceeds 8 hours, the effect of the reduction of the? Phase saturates and there is a problem in energy use. Therefore, in the present embodiment, the holding time at the heat treatment temperature is set to 1 minute to 8 hours.

The hot forging is performed on the hot extruded material (forging material), but even if the heat treatment is applied to the forged material, there is no significant influence on the mono-composition. This is because the history of the heat treatment is also cleared in order to heat the forging material before hot forging. However, in general, a brass alloy for hot forging is often used in a state of being extruded (not subjected to heat treatment) in view of the cost of heat treatment.

[0044]

By the above-described manufacturing method, the brass alloy hot work products of the first and second embodiments are produced.

[0045]

As described above, in the brass alloy hot work products of the first and second embodiments of the present invention, corrosion resistance is excellent, hot workability and machinability are good. Due to these characteristics, it is a suitable material for a water supply apparatus such as a water supply pipe, a joint and a valve, which is excellent in cost performance.

[0046]

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

Example

[0047]

Hereinafter, the results of verification tests conducted to confirm the effects of the present invention are shown. The following embodiments are for explaining the effects of the present invention, and the configurations, processes, and conditions described in the embodiments do not limit the technical scope of the present invention.

Hereinafter, in the evaluation results, the symbol " " means " excellent ", and the symbol " O " means " good ". The sign "? &Quot; means " fair ", the sign " x " means " poor ", and the sign " xx " .

[0048]

A brass alloy hot work product and a billet of a comparative composition according to the first and second embodiments of the present invention were produced. The composition of the copper alloy is shown in Tables 1 to 3.

The billets having the compositions shown in Table 1 were produced using a common melting furnace and a casting machine. Concretely, a billet having a diameter of 240 mm was produced by melting (melting) a copper alloy melt to be a predetermined component in a low frequency induction furnace, and by using a semi-continuous casting machine.

The billets of the compositions shown in Tables 2 and 3 were produced by a small scale dissolution facility in a laboratory. Specifically, a copper alloy melt was dissolved in a small high-frequency melting furnace so as to be a predetermined component, and the melt was injected into a mold to produce a billet having a diameter of 100 mm and a length of 125 mm.

[0049]

[0050]

[0051]

[0052]

(Hot extruded material)

The billet having the composition shown in Table 1 was cut to have a diameter of 240 mm and a length of 750 mm and extruded to a diameter of 12 mm by an indirect extruder of 2750 tons. Further, the billet was heated by an induction heating furnace before extrusion, and the extrusion temperature was set as shown in Table 4.

The cooling rate in the temperature range of 620 캜 to 450 캜 of the extruded bar material was determined under the conditions shown in Table 4. The temperature of the billet and the rod material after extrusion were measured using a radiation thermometer.

The extruded product after the hot extrusion process was subjected to heat treatment under the conditions shown in Table 4.

[0053]

(Hot forging material)

The billet having the composition shown in Table 1 was cut into 240 mm in diameter and 750 mm in length and extruded at a diameter of 20 mm by an indirect extruder of 2750 tons. The billet was heated by an induction heating furnace before extrusion, and the extrusion temperature was set as shown in Table 5. The cooling rate in the temperature range of 620 캜 to 450 캜 of the extruded bar material was determined under the conditions shown in Table 5. The rods were also cooled to room temperature (20 DEG C).

The obtained hot extruded material was cut into a cylindrical shape having a diameter of 20 mm and a length of 30 mm to collect a sample. The sample was heated to the temperature shown in Table 5, and a circumferential sample was placed with a friction press of 200 tons, and the sample was freely forged from a height of 30 mm to 12 mm (processing rate 60%). The cooling rate in the temperature range of 620 DEG C to 450 DEG C of the forging material was determined under the conditions shown in Table 5. This hot forging also cooled to room temperature (20 ° C).

[0054]

(Labo extrusion material 1)

A part of the billet having a diameter of 240 mm in the composition shown in Table 1 was cut and then the surface thereof was cut to obtain a hot-rolled extruded product having a diameter of 95 mm and a length of 120 mm. This was used as a billet for producing the Labo extruded material 1. This was heated to a temperature shown in Table 6 by a muffle furnace, and a hot extruded rod having a diameter of 20 mm was obtained by a 200-ton direct extruder.

The cooling rate in the temperature range of 620 캜 to 450 캜 of the rod material after extrusion was determined under the conditions shown in Table 6. The extruder was cooled to room temperature (20 ° C).

Further, the extruded product after the hot extrusion process was subjected to heat treatment under the conditions shown in Table 6.

[0055]

(Labo extrusion material 2)

The billet surface of the composition shown in Tables 2 and 3 was cut to have a diameter of 95 mm and a length of 120 mm. This was heated by a muffle furnace to temperatures shown in Tables 7 and 8, and a hot extruded 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 extruded bar material was determined under the conditions shown in Tables 7 and 8. The extruder was cooled to room temperature (20 ° C).

Further, for the extruded product after the hot extrusion process, heat treatment was performed under the conditions shown in Tables 7 and 8.

[0056]

(Labo forging material)

The billet surface of the composition shown in Tables 2 and 3 was cut to have a diameter of 95 mm and a length of 120 mm. This was heated to the temperatures shown in Tables 9 and 10 by a muffle furnace and a hot extruded rod having a diameter of 20 mm was obtained by a 200-ton direct extruder.

The cooling rate in the temperature range of 620 캜 to 450 캜 of the extruded bar material was determined under the conditions shown in Tables 9 and 10. The extruder 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 to collect a sample. The sample was heated to the temperatures shown in Tables 9 and 10, and a circumferential sample was set up with a friction press of 200 tons to be 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 forging material was determined under the conditions shown in Tables 9 and 10. The hot forging was cooled to room temperature (20 ° C).

The forged product after the hot forging process was subjected to heat treatment under the conditions shown in Tables 9 and 10.

[0057]

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

[0058]

(Hot extrudability)

In the case of the hot extruded material, it was determined that the portion which could not be extruded at a diameter of 12 mm could be extruded completely, "? &Quot;, the portion which was not extruded was " Xx ". Further, in the extrusion process which is practically and practically performed, not all the ingot (billet) is extruded into the bar material. If the entire portion is extruded, defects are generated in the rear end portion of the extruded material which becomes the ingot end portion, and the product is not formed. As a result, an extrusion process was carried out by leaving a certain amount of the ingot end portion. And the remaining portion of the ingot exceeding 50 mm remained in the extruding capacity of the mass production machine (the mass production machine) was evaluated as " x ".

In the case of the Labo extruded material, those having an extrusion length of 200 mm or more in a hot extruded rod having a diameter of 20 mm were evaluated as " ", and those having an extrusion length of less than 200 mm were evaluated as " I appreciated.

[0059]

(Hot forging)

Evaluation was made as " x " when the forge load exceeded 100 tons, and " xx " when cracks were found on the surface of the hot forging material. did. "○" evaluation is required for mono-composition. If the forging load exceeds 100 tons, it is difficult to forge in a short-circuited machine having a small capacity, and there is a possibility that a forged product having a complicated shape can not be formed.

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

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

[0068]

(Observation of metal structure)

As shown in Fig. 1, in the metal extrusion, the metal structure is divided into 1/4 portion of the diameter D (1/4 of the diameter D from the surface) in the direction parallel to the extrusion direction, 5 mm from the surface, and 3 mm from the surface when the material was 12 mm thick).

As for the hot forging material, as shown in Fig. 2, cross-sectional microstructures of 3 mm in thickness, which is 1/4 of the thickness from the surface, were observed in the cross section cut in the radial direction with respect to the portion outside 8 mm from the center. In the case of hot forging, when the plate is freely forged from a height of 30 mm to 12 mm, it becomes a disc shape having a diameter of about 32 mm.

This observation sample was etched with a mixed etching solution of 3 vol% aqueous hydrogen peroxide and 3 vol% ammonia water, and the metal structure was observed at a magnification of 200 times using a metallurgical microscope (EPIPHOTO 300 manufactured by Nikon Corporation).

[0069]

The area ratio of the β phase and the γ phase was calculated as the area ratio of the β phase and the γ phase with respect to the area of the entire metal structure observed by performing the binarization treatment on the observed metal structure using image processing software (WinRoof). The area ratio was measured with respect to an arbitrary three-view metal structure with respect to an area of 75 mm x 100 mm among them by enlarging the metal structure observed at a magnification of 200 times to a size of 195 mm x 243 mm (substantial magnification: 355 times) , With their average value. Three fields of view were measured for each non-overlapping area. In the binarization processing, the β phase and the γ phase portions were respectively classified into the 75 mm × 100 mm portions, and the classified areas were measured by using image processing software. The β phase and γ And the area ratio of each phase was measured.

The size and distribution (density) of the Pb particles were measured by the following methods. 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 metallurgical microscope, and the metal structure was enlarged to 195 mm x 243 mm (the actual magnification was 1775 times). The Pb particle portion was classified in the three field of view (75 mm x 100 mm: substantial evaluation area 0.06 mm ² ) in which the measurement field of view did not overlap, and the classified area was measured using an image processing software, and each Pb particle The average particle diameter was measured. Specifically, it is assumed that Pb particles are a circle, and the diameter of Pb particles is determined from the measured areas as the particle diameters. Then, the average value of the particle diameters of all the Pb particles observed was determined to be the average particle size. The distribution (density) of the Pb particles was measured as follows. The number of Pb particles was counted in the 3 o'clock range where the average particle size of the Pb particles was determined. The number of Pb grains in the entire measured portions was calculated and the number per 100 μm ² (10 μm × 10 μm) was calculated. Then, the average value of the three locations was obtained, and the distribution (density) was determined.

[0070]

The maximum lengths of the long sides of the? phase and? phase were binarized with respect to arbitrary three-view metal structures using image processing software (WinRoof) in the same manner as the area ratios of the? phase and? phase. Next, the absolute maximum lengths of the specified? -Phase and? -Phase were determined. Among the absolute maximum lengths of all the measured? -Phase and? -Phase, the largest value was taken as the maximum length. In the case of hot extruded material, there was a maximum length in the direction parallel to the extrusion direction and in the direction parallel to the flow direction of the material in the transverse direction in the case of hot forging.

[0071]

the maximum length of the long side of the? phase and the? phase is less than 20 占 퐉 (0 占 퐉, that is, the case where the? phase rate and the? phase rate are 0%) is the best, Is the next best. When the maximum length of the long sides of the? phase and the? phase is not less than 50 占 퐉 and not more than 100 占 퐉, there is no problem, and when the maximum length of the long sides of the? phase and? phase exceeds 100 占 퐉, problems may occur from the viewpoint of corrosion resistance.

The? -phase and? -phase are less corrosion resistant than the? -phase. Although corrosion resistance is enhanced by appropriate addition of Sn, Sb and Ni, there is a possibility that dezinc corrosion occurs in the? -Phase and? -Phase under severe conditions, and that from the viewpoint of corrosion resistance, Is preferably as short as possible, and preferably not more than 100 mu m.

[0072]

(Dezinc corrosion test)

As a dezinc corrosion test, dezinc corrosion resistance of each brass alloy material was evaluated by a dezinc corrosion test described in ISO6509-1 (Corrosion of metals and alloys-Determination of dezincification resistance of copper alloys with zinc-Part1: Test method). In other words, at a 1vol% cupric chloride solution maintained at 75 ℃ expose a surface observing the cross-sectional microstructure (by masking the exposed area to the 1cm ^2), it was immersed for 24 hours. Subsequently, microstructures were observed in the cross section perpendicular to the exposed surface, and the maximum dezinc corrosion depth, which is the deepest zinc corrosion depth, was measured on the entire exposed surface.

[0073]

The case where the maximum dezinc corrosion depth was less than 20 μm (0 μm, ie, the case where dezinc corrosion was not confirmed) was evaluated as "⊚", and when the maximum dezinc corrosion depth was less than 20 袖 m and less than 50 袖 m, I appreciated. A case where the maximum dezinc corrosion depth was 50 μm or more and less than 100 μm was evaluated as "Δ", and a maximum dezinc corrosion depth of 100 μm or more was evaluated as "×".

If the maximum zinc depletion depth is less than 100 占 퐉, it is determined that the zinc depletion layer has corrosion resistance. Therefore, if it is evaluated as "? &Quot;, it can be said that there is corrosion resistance (silver nitrate corrosion resistance).

[0074]

(Immersion test)

As a test in a severe corrosive environment, sodium hypochlorite was appropriately added to tap water, carbon dioxide gas was injected, and the test solution was adjusted by adjusting the residual chlorine concentration to 30 ppm and the pH to 6.8. The test piece was prepared by adjusting the exposed surface in the same manner as in the ISO6509 test. The specimen was immersed in the test liquid at a liquid temperature of 40 占 폚. After 8 weeks, the specimens were removed and the maximum dezinc corrosion depth was measured in the same manner as in the ISO6509 test.

[0075]

The case where the maximum dezinc corrosion depth was less than 20 μm (0 μm, ie, the case where dezinc corrosion was not confirmed) was evaluated as "⊚", and when the maximum dezinc corrosion depth was less than 20 袖 m and less than 50 袖 m, I appreciated. A case where the maximum dezinc corrosion depth was 50 μm or more and less than 100 μm was evaluated as "Δ", and a maximum dezinc corrosion depth of 100 μm or more was evaluated as "×".

In the immersion test, there is no criterion that there is clear internal zinc corrosion resistance. However, as in the ISO6509 test, it was judged that if the maximum dezinc corrosion depth is less than 100 占 퐉, the internal zinc corrosion resistance is present.

It is needless to say that in any dezinc corrosion test, the corrosion resistance is satisfactory as long as the maximum dezinc corrosion depth is low.

[0076]

(Machinability)

A hot extruded material (without heat treatment) having a diameter of 20 mm was prepared. A hole having a depth of 10 mm was drilled in the center of the hot extruded material (rod material) at a revolution of 1250 rpm and a feed rate of 0.17 mm / rev by a straight drill having a diameter of 3.5 mm. At that time, the torque applied to the drill and the resistance value of the thrust were measured, and the cutting resistance value, which is the square root mean square root of the torque and the thrust, was obtained. With reference to the cutting resistance value of JIS H3250 C3604, the machinability index was determined by the following formula, and the machinability was evaluated by the value.

Machinability index (%) = (cutting resistance value of each brass alloy material) / (cutting resistance value of C3604) × 100

A degree of machinability of 90% or more was evaluated as " ", and a machinability index of 75% or more and 90% or less was evaluated as "

If the machinability index is more than 75%, it is possible to cut industrially without a big difference from C3604.

Further, a rod having a diameter of 20 mm and a height of 30 mm was forged to a height of 12 mm, and a hot forging material (without heat treatment) was prepared. The test was conducted under the same conditions as in the case of a hot extruded material having a diameter of 20 mm by a straight drill having a diameter of 3.5 mm to evaluate the machinability of the hot forging material.

Tables 11 to 24 show various test results.

[0077]

[0078]

[0079]

[0080]

[0081]

[0082]

[0083]

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

Alloy No. 3 having a Cu content of 61.2 mass% In S137 (Test No. T137), the extrudability is good, but the extruded material has a β phase rate of 6%, a total of β phase and γ phase (β + γ) of 10% and a maximum length of β phase or γ phase of 150 μm And the ratio of the β phase and the γ phase was high and the maximum length of the β phase or the γ phase was long, so that the corrosion resistance (anti-drip zinc corrosion resistance) was not good.

Alloy No. 61 having a Cu content of 61.7% by mass; S40 (Test No. T40, T70) and alloy No. 61 having a Cu content of 61.8 mass%. Although there is no problem with the extrudability of the extruded material, the sum of the? -Phase and the sum of the? -Phase and the? -Phase is 3% to 4% and 5% The maximum length of the image is relatively long, i.e., 90 to 95 mu m. As for the corrosion resistance (anti-drip zinc corrosion resistance), the extruded material, the forgings, and the respective heat treatment materials are evaluated with DELTA, and there is no practical problem, but the corrosion resistance is somewhat lower than those of the alloys of the present invention.

[0092]

The Cu content is 64.1% by mass, and the alloy No. 7 having a relatively high Cu content is 64.1% by mass. S6 (Test Nos. T6, T16, T26) and Alloy No. Nos. In S31 (Test Nos. T31 and T61), the extrudability and the monocomponent were evaluated as "? &Quot;, and there was no problem. In some cases, extrusion was possible with the maximum capacity of the extruder. The extrudability is somewhat deteriorated in comparison with other alloys of the present invention under the same extrusion conditions.

Alloy No. 3 having Cu content of 64.7 mass% In S136 (Test No. T136), extrusion is impossible (extruded portion exists, extrusion length is less than 200 mm in laboratory extruded material), and there is a problem in mass production. However, the β phase and the γ phase are small and the corrosion resistance is good.

[0093]

An alloy No. 1 having a Pb content of 0.55% by mass; In S144 (Test No. T144), the other components are within the range of the present invention, and hot workability such as extrudability and corrosion resistance are not problematic (evaluation is?) And machinability is poor. This material has an average particle diameter of Pb particles of 0.1 mu m, a distribution (density) of 0.001 pore / 100 mu m < ^{2 &} gt ;, a small size and a low density, and poor machinability (machinability).

An alloy No. 2 having a Pb content of 2.15% by mass; In S145 (Test No. T145), the other components are within the range, and the hot workability, corrosion resistance and machinability are not problematic. However, if the amount of Pb is large, there is a possibility that the amount of elution to water increases, and a treatment for reducing the elution amount is required. This material has an average particle diameter of 3.0 m and a distribution (density) of 0.06 pb / 100 m < ² > ² , and the amount of Pb eluted as described above increases.

If the content of Pb is within the range of the present invention, the machinability evaluation becomes "? &Quot; or "? &Quot;, which is excellent. Since the machinability affects not only Pb but also the metal structure, it can not be evaluated only by the content of Pb, but it is a sample containing many in the appropriate range that the evaluation is "⊚".

The average particle size and distribution (density) of Pb particles are slightly influenced by the conditions of hot working (hot extrusion, hot forging) and the conditions of heat treatment. Alloy No. In S5, when the heat treatment temperature was as high as 580 占 폚 (Test No. T5-2), the average particle diameter of Pb exceeded 3 占 퐉 causing a problem in the amount of elution. In addition, When the hot extrusion temperature of the Labo extruded material of S1 is as high as 850 캜 (Test No. T21-3), the average particle diameter of Pb exceeds 3 탆. Alloy No. In S37, S44 and S45, when the hot forging temperature was as high as 840 DEG C or higher (Test Nos. T67-3, T74-2, T75-3), surface cracks occurred and there was a problem with hot workability, And the subsequent heat treatment was not conducted. Also, when the hot forging temperature of the same alloy is lower than 670 ° C (Test Nos. T67-5, T74-3 and T75-5), the deformation resistance is high and the load during hot forging exceeds 100t, The heat treatment was not conducted. Only the average particle size and distribution of Pb particles with respect to these alloys were examined. As a result, In S37, Pb average particle size exceeded 3 μm when hot forging was performed at 850 ° C. (Test No. T67-3). Also, No. In S44 and S45, when the hot forging temperature was 840 占 폚 (Test Nos. T74-2 and T75-3), the distribution of Pb was 0.001 / 100 占 퐉 ² , and the machinability (machinability) was not good. In addition, In S44, when the hot forging temperature was as low as 650 占 폚 (Test No. T74-3), the average particle size of Pb became 0.1 占 퐉, and the machinability (machinability) was not good. When the average particle diameter and the distribution of Pb are out of an appropriate range, there arises a problem in machinability or elution of Pb. When they are in the appropriate range, they are excellent without problems in machinability evaluation.

[0094]

Alloy No. 1 having a Sn content of 0.45 mass% In S141 (Test No. T141), if the other composition was in the appropriate range, there was no problem in extrudability or metal structure, but the evaluation was negative in the immersion test and the corrosion resistance was poor.

An alloy No. 1 having a Sn content of 1.10% by mass; In S142 (Test No. T142), the? -Phase is increased and the sum (? +?) Of the? -Phase and the? -Phase exceeds 5%. As a result, the corrosion resistance is poor and the corrosion resistance is poor even after the heat treatment.

[0095]

Sn, which varies depending on the contents of other elements as well as Sn, but contains Sn in an amount of 0.57% by mass. In S46 (Test Nos. T46 and T76), the corrosion resistance is evaluated by a large degree (it is judged practically that there is no problem and corrosion resistance), and when the content of Sn is small, the corrosion resistance tends to deteriorate.

On the other hand, if the content of Sn is large, the? Phase tends to increase, but there is no problem within the scope of the present invention. An alloy No. 1 having a Sn content of 0.96 mass%; In S49 (Test Nos. T49 and T79), the γ phase of the hot extruded material or the hot forging was large, and the corrosion resistance evaluation was also large.

As described above, the corrosion resistance is improved by the content of Sn, but if it exceeds the proper range, the? Phase is increased in the metal structure and the corrosion resistance is deteriorated to the contrary.

[0096]

An alloy No. 1 having a Ni content of 0.018 mass%; In S140 (Test No. T140), the other elements are in an appropriate range, but the corrosion resistance is inferior and there is a problem.

An alloy No. 1 having a Ni content of 0.021% by mass; S41 (Test Nos. T41 and T71) has a compositional relation f3 = [Ni] / [Sb] which is low. However, in the evaluation of corrosion resistance, It was somewhat out of place in inventive alloys.

The content of Ni is 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 elution amount of Ni increases with respect to water. Although depending on the contents of the other elements and the compositional relational expression, when the content of Ni is large, the corrosion resistance evaluation is also increased, and the corrosion resistance is improved.

[0097]

An alloy No. 1 having a Sb content of 0.015% by mass; S143 (Test No. T143) and an alloy No. Sb having a Sb content of 0.018 mass%. In S138 (Test No. T138), the content of Sb is less than the range of the present invention, and corrosion resistance is poor.

An alloy No. 1 having a Sb content of 0.024% by mass; S34 (Test Nos. T34 and T64) and an alloy No. Sb having a Sb content of 0.028 mass%. In S43 (Test Nos. T43 and T73), the corrosion resistance is evaluated by a large amount, and there is practically no problem with the corrosion resistance, but Sb affects the corrosion resistance.

On the other hand, the alloy No. 1 in which the Sb content is 0.085 mass% In S139 (Test No. T139), since the content of Sb is large, corrosion resistance is good, but cracking occurs during hot extrusion, and hot workability is poor. If Sb is within the range of the present invention, the addition amount of other added elements or the compositional relational expression is affected, but the corrosion resistance is improved.

[0098]

P, Mn and Fe are inevitable impurities, but if they are within the ranges shown in the examples, they do not significantly affect the hot workability, corrosion resistance and the like.

P is 0.02 mass% or less. S5 (Test Nos. T5-1 to 11 and T15), there were no problems in casting, hot workability (extrudability, mono-composition). On the other hand, the alloy No. 1 having a P content of 0.026 mass% In S7 (Test Nos. T7 and T17), cracks occurred during hot working (hot extrusion, hot forging).

[0099]

An alloy No. 1 having a compositional relationship f1 of 60.32; In S101 (Test No. T101), there is no problem in hot workability, but the β phase and the γ phase are large and the maximum length is long, resulting in poor corrosion resistance.

An alloy No. 1 having a compositional relationship f1 of 60.63; In S56 (Test Nos. T56 and T86), although the β and γ phases were somewhat larger, the corrosion resistance evaluation was Δ.

An alloy No. 1 having a compositional relationship f 1 of 64.09; In S135 (Test No. T135), there is a problem in the hot workability, such as less β phase and γ phase, and good corrosion resistance, but cracking occurs at the time of extrusion.

[0100]

An alloy No. 1 having a compositional relationship f1 of 63.65; In S35 (Test No. T35, T65), the β phase and the γ phase are small, and the corrosion resistance is also good. As for the hot workability, the extrusion length in the laboratory extrusion was 200 mm or more, but it is shorter than other alloys of the present invention and is close to the limit of hot workability.

When the numerical value of the compositional relationship formula f1 is within an appropriate range, it is also affected by other elements and the like, but the evaluation of corrosion resistance tends to be good. As far as the compositional relationship f1 is concerned with the hot workability and the corrosion resistance, it is important for the alloy of the present invention that it falls within an appropriate range.

[0101]

The alloy No. 1 in which the compositional relationship f2 is 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 such as β-phase and γ-phase was preferentially dezincified by corrosion. Further, there was no problem with hot workability.

On the other hand, the alloy No. 1 having the compositional relationship f2 of 0.132 was obtained. In S134 (Test No. T134), although the corrosion resistance is good, a problem arises in hot workability, such as cracks occurring in hot extrusion.

[0102]

The alloy No. 1 in which the compositional relationship f2 is 0.033; In S53 (Test Nos. T53 and T83), there was no problem in hot extrusion property, and in the dezinc corrosion test of ISO6509, the evaluation was also evaluated as?, But in the immersion test, all evaluation was? And in the case of heat treatment, .

An alloy No. 1 having a compositional relationship f2 of 0.11; S42 (Test Nos. T42 and T72), an alloy No. 1 having a compositional relationship f2 of 0.105. In S55 (Test No. T55, T85), the corrosion resistance is also comparatively good, and the corrosion resistance is evaluated by performing heat treatment. However, cracks in the surface of the extruded tip portion were not observed, but unevenness was present and indications were close to the limit at which cracks occurred.

In addition, when the compositional relationship f2 is within an appropriate range, the hot workability or corrosion resistance is also good. Of course, the compositional relation f2 is largely concerned with hot workability and corrosion resistance as described above, but each characteristic is influenced by other compositional relations and additive elements.

[0103]

An alloy No. 1 having a compositional relationship f3 of 0.28; In S132 (Test No. T132), the content of the additive element is in the proper range of the present invention, but the corrosion resistance is poor. It is considered that the effect of the Ni and Sb on the corrosion resistance is lowered because the value of the compositional formula f3 is small.

An alloy No. 3 having a compositional relationship f3 of 0.38; In S54 (Test Nos. T54 and T84), all of the corrosion resistance of the immersion test was evaluated as DELTA, and the evaluation was slightly lower, but the level was judged to be corrosion resistance. If the compositional relationship f3 is within an appropriate range, it is influenced by the contents of other elements and other compositional relations, but exhibits good corrosion resistance.

[0104]

Alloy No. 3 with compositional relationship f3 of 3.73; In S143 (Test No. T143), the content of Sb is low and corrosion resistance is poor. When Sb is 0.03% by mass or less, which is the lower limit of the preferable range, depending on the content of Ni and Sb, for example, the content of Ni becomes 0.105% by mass or more when Ni / Sb is 3.5 or more. The upper limit of the range is exceeded. When the value of the relational expression f3 is large in this way, the upper limit is set to 3.5 because there is a large amount of Ni, and there is a problem in the elution amount of Ni, or Sb is low and there is a risk of corrosion resistance.

[0105]

Next, 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 , And hot working conditions.

When the temperature condition at the time of hot working (hot extrusion, hot forging) is as high as 840 ° C or 850 ° C, cracks are generated in the extruded material and surface cracks occur in the forged product. In addition, Under the conditions of high temperature during hot working such as T21-3 or T67-3, the average particle size of Pb becomes large and the elution amount of Pb also increases, which has an adverse effect.

On the other hand, when the temperature condition at the time of hot working (hot extrusion, hot forging) is as low as 640 ° C. or 650 ° C., extrusion is impossible (extrusion length is less than 200 mm in laboratory extruded material) The deformation resistance of the material at a high temperature is increased, and the hot workability is lowered. Test No. When the hot extrusion temperature of T21-5 is as low as 640 占 폚, the particle size of Pb is small and the distribution exceeds 0.06 / 100 占 퐉 ² , and in this case, there arises a problem in the elution amount of Pb. The temperature conditions at the time of hot working (hot extrusion, hot forging) affect not only the workability at the time of hot working but also particle size and distribution of Pb.

[0106]

When the cooling rate in the temperature range from 620 ° C to 450 ° C exceeds 200 ° C / min (Test Nos. T5-11 and T21-7) after hot working (hot extrusion, hot forging) The corrosion resistance is poor due to many phases and a long maximum length.

On the other hand, when the cooling rate is slower than 2 DEG C / min, the above cooling rate is not performed. However, if the cooling rate is 1 DEG C / min, for example, the cooling time becomes 170 minutes.

[0107]

Next, T5-1 to T5-10, and T12-1 to T12-7, confirm the heat treatment conditions.

When the conditions of the heat treatment of the hot extruded material and the hot forged product exceed 560 占 폚, the? Phase is large and the maximum length is also long, and the corrosion resistance is poor.

When the conditions of the heat treatment of the hot extruded material and the hot forging product are less than 470 캜, the γ phase increases and the maximum length is longer than other conditions, and the corrosion resistance is deteriorated.

The holding time is the same as that in the extruded condition under the condition of less than 1 minute, and the effect of the heat treatment is not seen. On the other hand, if it exceeds 8 hours (480 minutes), there is no big difference from the condition within 8 hours, and only the cost for the heat treatment is increased.

[0108]

As described above, the alloy of the present invention in which the contents of the respective added elements and the compositional relational expressions are within the appropriate range has excellent hot workability (hot extrusion, hot forging), and is also excellent in corrosion resistance and machinability. Further, in order to obtain excellent properties in the alloy of the present invention, it can be achieved by setting the production conditions in the hot extrusion and the hot forging and the conditions in the heat treatment to an appropriate range.

[0109]

The brass alloy hot work product of the present invention is excellent in hot workability (hot extrudability and hot weather resistance) and excellent in corrosion resistance and machinability. As a result, the brass alloy hot work product of the present invention can be suitably applied as a constituent material of a water supply mechanism such as a water supply pipe, seam, and valve.

Claims (10)

Cu: not less than 64.5 mass%, Pb: not less than 0.6 mass% and not more than 2.0 mass%, Sn: not less than 0.5 mass% and not more than 1.0 mass%, Sb: not less than 0.02 mass% and not more than 0.08 mass% 0.10% by mass or less, the balance being Zn and inevitable impurities, the content of P being an unavoidable impurity is 0.02% by mass or less,
The Cu content is set to [Cu] mass%, the Pb content to the [Pb] mass%, the Sn content to the [Sn] mass%, the Sb content to the [Sb] mass%, and the Ni content to the [Ni] In one case,
60.5? [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]? 64.0,
0.03? [Sb] / [Sn]? 0.12,
0.3? [Ni] / [Sb]? 3.5,
Wherein the metal structure is an alpha -phase matrix and contains Pb particles, and the area ratio of the sum of the area ratio of the beta phase and the area ratio of the gamma phase is 0% or more and 5% or less and the length of each of the long sides of the? By weight or less. Cu: not less than 64.0 mass%, Pb: not less than 0.7 mass% and not more than 2.0 mass%, Sn: not less than 0.60 mass% and not more than 0.95 mass%, Sb: not less than 0.03 mass% and not more than 0.07 mass% 0.095% by mass or less, the remainder being composed of Zn and inevitable impurities, the content of P being an unavoidable impurity is 0.02% by mass or less,
The Cu content is set to [Cu] mass%, the Pb content to the [Pb] mass%, the Sn content to the [Sn] mass%, the Sb content to the [Sb] mass%, and the Ni content to the [Ni] In one case,
60.7? [Cu] + 0.5 x [Pb] -2 x [Sn] -2 x [Sb] + [Ni]? 63.6,
0.035? [Sb] / [Sn]? 0.10,
0.4? [Ni] / [Sb]? 3.5,
Wherein the metal structure is an alpha -phase matrix and contains Pb particles, and the area ratio of the sum of the area ratio of the beta phase and the area ratio of the gamma phase is 0% or more and 5% or less and the length of each of the long sides of the? By weight or less. The method according to claim 1 or 2,
Wherein the Pb particles have an average particle diameter of 0.2 占 퐉 or more and 3 占 퐉 or less. The method according to claim 1 or 2,
Brass alloy hot work piece, characterized in that the distribution is 0.002 pieces / 100μm ² or less than 0.06 piece / 100μm ² of the Pb grains. The method according to claim 1 or 2,
Wherein the average particle diameter of the Pb particles is 0.2 占 퐉 or more and 3 占 퐉 or less and the distribution of the Pb particles is 0.002 / 100 占 퐉 ² or more and 0.06 / 100 占 퐉 ² or less Brass alloy hot work products. The method according to claim 1 or 2,
A brass alloy hot work product characterized by being used as a water-based appliance. A method for producing a brass alloy hot work product for manufacturing a brass alloy hot work product as set forth in claim 1 or claim 2,
Characterized in that the hot working is performed at a temperature of 670 DEG C or higher and 820 DEG C or lower and the temperature region from 620 DEG C to 450 DEG C is cooled at an average cooling rate of 200 DEG C / minute or less. The method of claim 7,
Wherein the heat treatment is performed at a temperature of 470 DEG C to 560 DEG C for 1 minute to 8 hours after the hot working. delete delete

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