TWI645053B - Hot worked product of brass alloy and method for manufacturing hot worked product of brass alloy - Google Patents

Abstract

The present invention provides a method for producing a brass alloy hot worked product and a brass alloy hot processed product. The brass alloy hot-worked product includes Cu: 61.5 to 64.5 mass%, Pb: 0.6 to 2.0 mass%, Sn: 0.55 to 1.0 mass%, Sb: 0.02 to 0.08 mass%, and Ni: 0.02 to 0.10 mass. %, the margin includes Zn and unavoidable impurities, and satisfies the following formula, 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

Brass alloy hot processed product and brass alloy hot processed product manufacturing method

The present invention relates to a brass alloy hot worked product (a hot worked product of a brass alloy) excellent in corrosion resistance and a method for producing the brass alloy hot worked product. The present application claims priority from Japanese Patent Application No. 2016-104136, filed on Jan.

As the brass alloy hot-worked material (hot extruded rod or hot forged product), JIS H3250 C3604 (fast-cut brass) or C3771 (mainly used) is used from the viewpoint of excellent machinability (cuttability) or forgeability. Forging with brass). However, in the brass alloy materials, the metal phase includes the α phase and the β phase, and contains a β phase having a poor corrosion resistance. Therefore, if it is used in a corrosive environment such as a faucet machine in contact with tap water, dezincification is liable to occur. Corrosion, and water leakage due to long-term corrosion.

Among them, in order to improve the dezincification resistance of the brass alloy material, a γ phase having an area ratio of 5% or more is precipitated. Patent Document 1 discloses a dezincification-resistant brass joined member containing 1.5 mass% or more of Sn in a β phase. Further, Patent Document 2 proposes a material including a copper alloy which is improved in dezincification corrosion resistance, and in the copper alloy, Cu: 61.0 to 63.0 mass%, Pb: 2.0 to 4.5 mass%, and P: 0.05 to 0.25 mass%. Ni: 0.05 to 0.30 mass%, and the balance is Zn.

The alloy disclosed in Patent Document 1 contains an alloy of a large amount of hard and brittle γ phase, and there is a problem that cracks are likely to occur in a water hammer phenomenon such as a faucet machine to which a force is applied. Further, the dezincification resistance of the γ phase is superior to that of the β phase but is inferior to that of α. Therefore, in the case where a large amount is present, dezincification corrosion preferentially occurs in the γ phase. On the other hand, the copper alloy disclosed in Patent Document 2 does not contain Sn, and therefore has substantially poor dezincification resistance, and when P is contained in a large amount, there is a problem in production such as cracking during casting. [Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2002-069552 (Patent Document 2)

The present invention has been made to solve the above problems of the prior art, and an object of the present invention is to provide a brass alloy hot worked product and a brass alloy hot worked product which are excellent in corrosion resistance such as dezincification resistance and excellent in hot workability. method.

According to the present invention, the brass alloy hot-worked product according to the first aspect of the present invention is characterized by comprising Cu: 61.5 mass% or more and 64.5 mass% or less, Pb: 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, and the balance includes Zn and unavoidable impurities, The content of Cu is set to [Cu]mass%, the content of Pb is set to [Pb]mass%, the content of Sn is set to [Sn]mass%, and the content of Sb is set to [Sb]mass%, and Ni is used. When the content is set to [Ni]mass%, it satisfies the following: 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.

The brass alloy hot-worked product according to the second aspect of the present invention is characterized by comprising Cu: 62.0 mass% or more and 64.0 mass% or less, Pb: 0.7 mass% or more, 2.0 mass% or less, and Sn: 0.60 mass% or more. And 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, the balance includes Zn and unavoidable impurities, and the content of Cu is set to [Cu] mass% The content of Pb is [Pb]mass%, the content of Sn is [Sn]mass%, the content of Sb is [Sb]mass%, and the content of Ni is [Ni]mass%. Next, it satisfies the following: 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 according to a third aspect of the present invention is characterized in that, in the brass alloy hot worked product, the metal phase is an α phase base, and the Pb particles are included, and the area ratio of the β phase and the area of the γ phase. The total area ratio of the rate is 0% or more and 5% or less.

A brass alloy hot-worked product according to a fourth aspect of the present invention is characterized in that, in the brass alloy hot-worked product, the metal phase is an α phase base, and each of the long sides of the Pb particles, the β phase or the γ phase is contained. The length is 100 μm or less.

A brass alloy hot-worked product according to a fifth aspect of the present invention is characterized in that, in the brass alloy hot-worked product, the metal phase is an α phase base and contains Pb particles, and the Pb particles have an average particle diameter of 0.2 μm or more. And 3 μm or less.

A brass alloy hot-worked product according to a sixth aspect of the present invention is characterized in that, in the brass alloy hot-worked product, the metal phase is an α phase base, and the Pb particles are contained, and the Pb particles have a distribution of 0.002 / 100 μm ² The above is 0.06 / 100 μm ² or less.

A brass alloy hot-worked product according to a seventh aspect of the present invention is characterized in that in the brass alloy hot-worked product, the metal phase is an α phase base, and Pb particles are contained, and the Pb particles have an average particle diameter of 0.2 μm or more. Further, it is 3 μm or less, and the distribution of Pb particles is 0.002 / 100 μm ² or more and 0.06 / 100 μm ² or less.

A brass alloy hot-worked product according to an eighth aspect of the present invention is characterized in that it is used as an apparatus for a water pipe in the brass alloy hot-worked product.

A method for producing a brass alloy hot-worked article according to a ninth aspect of the present invention is characterized in that, in the method for producing a brass alloy hot-worked article of the brass alloy hot-worked product, at 670 ° C or higher and 820 ° C The hot working is performed at the following temperature, and the temperature range of 620 ° C to 450 ° C is cooled at an average cooling rate of 200 ° C / min or less.

A method for producing a brass alloy hot-worked article according to a tenth aspect of the present invention is characterized in that, in the method for producing a brass alloy hot-worked product, after the hot working, the temperature is 470 ° C or higher and 560 ° C or lower. At a temperature, heat treatment is performed for 1 minute or more and 8 hours or less. [Effect of the invention]

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

Hereinafter, a method of producing a brass alloy hot-worked product and a brass alloy hot-worked product according to an embodiment of the present invention will be described. The brass alloy hot-worked product of the present embodiment is used as an apparatus for a water supply pipe such as a water supply tap metal part, a joint, or a valve. Further, as the brass alloy hot-worked product of the present embodiment, a brass alloy hot extruded rod or a brass alloy hot forged product is used.

Here, in the present specification, such as [Zn], the element symbol in parentheses indicates the content (mass%) of the element. Further, in the present embodiment, as described below, a plurality of compositional expressions are defined by the method of expressing the content. Composition relationship f1=[Cu]+0.5×[Pb]-2×[Sn]-2×[Sb]+[Ni] Composition relation f2=[Sb]/[Sn] Composition relationship f3=[Ni] /[Sb]

The brass alloy hot-worked product according to the first embodiment of the present invention contains Cu: 61.5 mass% or more and 64.5 mass% or less, Pb: 0.6 mass% or more and 2.0 mass% or less, and 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 includes Zn and unavoidable impurities, and the compositional relationship f1 is set in the range of 60.5 ≤ f1 ≤ 64.0, and the composition The relation f2 is set in the range of 0.03 ≤ f2 ≤ 0.12, and the composition relation f3 is set in the range of 0.3 ≤ f3 ≤ 3.5.

The brass alloy hot-worked product according to the second embodiment of the present invention contains Cu: 62.0 mass% or more and 64.0 mass% or less, Pb: 0.7 mass% or more and 2.0 mass% or less, and Sn: 0.60 mass% or more and 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, the balance contains Zn and unavoidable impurities, and the composition relationship f1 is set in the range of 60.7 ≤ f1 ≤ 63.6, and the composition The relation f2 is set in the range of 0.035 ≤ f2 ≤ 0.10, and the composition relation f3 is set in the range of 0.4 ≤ f3 ≤ 3.5.

Further, in the brass alloy hot-worked article according to the first and second embodiments of the present invention, the metal phase is an α phase base, and the Pb particles are included, and the area ratio of the β phase and the area ratio of the γ phase are set to be the total area ratio. It is 0% or more and 5% or less. Further, the length of each long side of the β phase or the γ phase is set to 100 μm or less.

Hereinafter, the reason why the component composition and the compositional relationship formulas f1, f2, and f3 and the metallographic phase are defined as described above will be described.

(Cu) Cu is a main element of the alloy of the present invention and is greatly affected by the relationship with Sn, Pb, and Zn. However, in the hot extruded material and hot forged product which are hot processed materials of the alloy of the present invention, Excellent corrosion resistance and dezincification resistance, Cu needs to be 61.5 mass% or more, and 62.0 mass% or more is preferable. On the other hand, when the content of Cu exceeds 64.5 mass%, the ratio of β which is equal to the deformation resistance at the time of hot working, that is, hot extrusion and hot forging, is lowered. Therefore, the hot deformation resistance becomes large, and the hot working temperature for performing appropriate hot working becomes high. Moreover, not only hot extrusion property and hot forgeability which are hot workability are deteriorated, but also machinability is deteriorated, strength is also low, and corrosion resistance is also saturated. Therefore, the upper limit of the content of Cu is 64.5 mass% or less, and 64.0 mass% or less is preferable.

(Pb) Pb is contained in order to improve machinability (machinability). Therefore, Pb needs to be 0.6 mass% or more. 0.7 mass% or more is preferable, and in the case where machinability is required, it is 1.0 mass% or more. As the content of Pb increases, the machinability is improved. On the other hand, when Pb exceeds 2.0 mass%, the amount of elution into water increases, and the environmental load may increase. Therefore, the upper limit of the content of Pb is 2.0 mass%. Further, Pb is mostly not dissolved in the mother phase of the copper alloy, and therefore exists as Pb particles. The size and distribution of Pb particles have a great influence on the machinability (cuttability), and also affect the amount of Pb eluted. In order to improve machinability (workability), it is desirable that the size of the Pb particles is small and uniform and high-density distribution. On the other hand, the larger the area of the Pb particles which are in contact with the aqueous solution such as the contact tap water, the larger the elution amount of Pb, and the larger the amount of elution, the size of the Pb particles which are opposite to the machinability (the machinability). distributed. Therefore, in order to balance the machinability (cuttability) and the amount of elution required for the alloy of the present invention, the size and distribution of the Pb particles are respectively in an appropriate range. For the machinability (cuttability), the average particle diameter 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 extend to the cutting surface during cutting, and the area of the Pb increases. Therefore, as a result, the area of Pb in contact with the 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 it is not possible to function as a chip breaker for improving machinability. The distribution of Pb particles is represented by the number (density) of Pb particles having a cross-sectional area of 100 μm ² . The distribution (density) of the Pb particles is 0.002 / 100 μm ² or more, and when it is 0.06 / 100 μm ² or less, it contributes to machinability (machinability). When the distribution of the Pb particles is less than 0.002 / 100 μm ² , the Pb particles are present in a low amount, and do not function as a chip breaker, resulting in a small machinability index (less than 75%). Further, the distribution of the Pb particles is more advantageous from the viewpoint of machinability (workability), but is less preferable from the viewpoint of elution of Pb. When the Pb particles are in contact with the cutter during the cutting, a part of the Pb particles are dissolved due to the heat generated at the time, and extend in the moving direction of the cutter, thereby substantially existing in a wide range of the cutting surface. Therefore, if the distribution of the Pb particles is large, the amount of Pb present on the surface after the cutting is inevitably increased, and the amount of elution of Pb is inevitably increased. When the leaching amount (dissolution amount) of Pb is measured by JIS S3200-7 (apparatus for tap water pipe - leaching performance test method), even if capacity correction is performed, the average particle diameter of Pb particles is sufficient when it exceeds 0.007 mg/L. More than 3 μm, and the distribution of particles exceeds 0.06 / 100 μm ² . In addition, the upper limit of the standard of the leachate in the terminal water supply tap described in the No. 1st No. 5 of the lead leaching amount (dissolution amount) (when the copper alloy is used as the main member) is exceeded. Standard materials cannot be used as end water supply taps. Therefore, the upper limit of the distribution (density) of the Pb particles is 0.06/100 μm ² or less which does not cause a problem in the elution amount (the amount of elution). As described above, the average particle diameter of the Pb particles is 0.2 to 3 μm, and the distribution is 0.002 to 0.06 / 100 μm ² .

(Sn) Sn is greatly affected by the relationship between Cu and Zn, but for copper alloys, corrosion resistance under severe water quality is improved, and dezincification resistance is particularly improved. Further, Sn reduces the thermal deformation resistance during hot working, that is, during hot extrusion and hot forging. In order to achieve this, Sn needs to be 0.55 mass% or more, 0.60 mass% or more is preferable, and 0.65 mass% or more is more preferable. On the other hand, when Sn is contained in an amount exceeding 1.0 mass%, the proportion of the γ phase or the β phase is increased, and the corrosion resistance is inversely problematic. Therefore, the upper limit of the content of Sn is 1.0 mass% or less, and 0.95 mass% or less is preferable.

(Sb) Sb is a copper alloy that improves the corrosion resistance under severe water quality, and is particularly resistant to dezincification. When Sn and Ni are added together, the effect is further exerted. In order to exhibit excellent corrosion resistance, Sb needs to be 0.02 mass% or more, preferably 0.03 mass% or more, and more preferably 0.035 mass% or more. On the other hand, even if Sb is contained in an amount of more than 0.08 mass%, not only the effect is saturated, but also the hot workability is adversely affected, and the cold workability is also deteriorated. Therefore, the upper limit of the content of Sb is 0.08 mass% or less, preferably 0.07 mass% or less, more preferably 0.065 mass% or less.

(Ni) When Ni is added together with Sn and Sb, the copper alloy is improved in corrosion resistance and dezincification resistance under severe water quality, and particularly plays the role of maximizing the effect of Sb. In order to exhibit excellent corrosion resistance, Ni needs to be 0.02 mass% or more, and preferably 0.025 mass% or more. On the other hand, when Ni is contained in an amount exceeding 0.10 mass%, there is a problem that the elution amount of Ni increases under severe water quality. Therefore, the upper limit of the content of Ni is 0.10 mass% or less, and preferably 0.095 mass% or less.

(Inevitable Impurity) For the copper alloy containing Pb, cutting chips or waste products are used as main raw materials from the viewpoint of recycling and cost. In the cutting chips, various elements such as Fe are mixed due to, for example, tool wear. Among the scrap products, there are cases where plating of Cr or the like is performed. Since these are used as raw materials, more inevitable impurities are mixed in comparison with other copper alloys. For example, the amount of Fe regarded as an impurity is allowed to 0.5 mass% in a copper alloy (C3604) containing about 3 mass% Pb and a copper alloy (C3605) containing about 4 mass% Pb prescribed by JIS H 3250. Therefore, in the alloy of the present invention, it is considered that the inevitable impurities such as Fe, Cr, Mn, and Al are allowed to be 1.0 mass% in total, without causing a significant influence on the characteristics. P acts to improve the corrosion resistance of the copper alloy in the same manner as Sb. However, even if a small amount is mixed, when the ingot is produced, cracks are likely to occur on the surface or inside, and cracks are likely to occur on the surface of the material during hot working. Although it is based on the content of Cu, Pb, Sn, and Ni, for example, when the content of P exceeds 0.02 mass%, there is a problem in the case of producing an ingot or a problem in hot working. Therefore, even if P is mixed, the upper limit value is added. It is preferable to set it as 0.02 mass% or less.

(Compositional relationship f1) In order to exhibit excellent corrosion resistance, in order to ensure good hot workability, it is only required that the content range of each element such as Cu, Sn, and Ni is insufficient. When the content of Cu is set to [Cu]mass%, the content of Pb is set to [Pb]mass%, the content of Sn is set to [Sn]mass%, and the content of Sb is set to [Sb]mass% and When the content of Ni is set to [Ni]mass%, the value of the compositional relationship f1=[Cu]+0.5×[Pb]-2×[Sn]-2×[Sb]+[Ni] is less than 60.5, and the obtained value cannot be obtained. Good corrosion resistance. Further, in the process after hot working (hot extrusion, hot forging), excellent corrosion resistance cannot be exhibited even if heat treatment is performed. Therefore, the lower limit of the compositional relationship f1 is 60.5 or more, preferably 60.7 or more, and more preferably 61.0 or more. On the other hand, if the value of the compositional relationship f1 = [Cu] + 0.5 × [Pb] - 2 × [Sn] - 2 × [Sb] + [Ni] exceeds 64.0, the thermal deformation resistance becomes high, and again, heat The deformation ability is deteriorated, so that it is impossible to ensure good hot workability, that is, hot extrusion property and hot forgeability. For example, although it is also based on hot working temperature or equipment capacity, good hot workability means that there is no crack on the surface of the extruded rod with respect to hot extrusion, and whether it can be extruded into a minimum of practical use. The size is φ12mm. Regarding hot forging, it is possible to forge to a thin wall without causing cracks on the surface of the forged product. Therefore, the upper limit of the compositional relationship f1 is 64.0 or less, 63.6 or less is preferable, and 63.0 or less is more preferable.

(Composition relation f2) Only a predetermined amount of Sb and Sn are contained, and it is not possible to obtain very excellent corrosion resistance and dezincification resistance. Both of Sn and Sb have a solid solution in the stable β phase at a high temperature of 600 ° C or higher compared to the base α phase. Alternatively, Sn and Sb have a solid solution in the stable γ phase more than the base α phase at a low temperature side of 475 ° C or lower, particularly 450 ° C or lower. Although based on the ratio to the α phase, the β phase, and/or the γ phase, for the composition of the alloy of the present invention, the amount of Sn, Sb dissolved in the β phase is larger than the amount of Sn, Sb dissolved in the α phase. About 2 to 7 times more. Further, the amount of Sn and Sb which are solid-solved in the γ phase is approximately 7 to 15 times more solid solution than the amount of solid solution in the α phase. First, in order to make the corrosion resistance of the base α phase excellent, the existence ratio of Sb and Sn is important, provided that Sb and Sn are within the aforementioned composition range. When the compositional relationship f2 = [Sb] / [Sn] is 0.03 ≤ f2 ≤ 0.12, the effect of adding Sn and Sb together is more remarkable, and the corrosion resistance of the α phase is most improved. The lower limit of the compositional relationship f2 is 0.035 or more, and the upper limit of the compositional relationship f2 is preferably 0.10 or less.

The β phase of the Cu—Zn—Sn-based alloy is difficult to be excellent in corrosion resistance, but the compositional relationship f2=[Sb]/[Sn] satisfies 0.03≤f2, and preferably satisfies 0.035≤f2. The corrosion resistance of the β phase and the corrosion resistance of the extruded material or the forged product. The alloy of the present invention is improved in hot workability by forming a β phase having a low heat deformation resistance at a high temperature, but as the temperature is lowered, the β phase becomes an α phase, whereby corrosion resistance is improved. However, the grain boundary and the phase boundary from the β phase to the α phase have problems in corrosion resistance. When the value of the compositional relationship f2 = [Sb] / [Sn] is at least 0.03 or more and 0.12 or less, the grain boundary and the phase boundary corrosion resistance are improved. When the temperature becomes 475 ° C or lower or 450 ° C or lower, when the β phase becomes the α phase, the concentrations of Sn and Sb which are solid-solubilized in the β phase become higher, thereby generating the γ phase. When 0.03 ≤ f2 ≤ 0.12, the grain boundary of the α phase and the γ phase, the phase boundary, and the corrosion resistance of the γ phase itself are further improved. When the compositional relationship f2 = [Sb] / [Sn] exceeds 0.12, the amount of Sb is excessive compared with Sn, and the thermal deformation ability of the α phase and the β phase is lowered to deteriorate the hot workability.

(Composition relation f3) Similarly to the compositional relationship f2=[Sb]/[Sn], the relationship between Ni and Sb is also important. Due to the presence of Ni, the corrosion resistance of the α phase and the γ phase of the base, the effect of Sb is further improved, and the corrosion resistance to the β phase is also improved. In particular, the grain boundary and phase boundary when the β phase which is stable from a high temperature is changed to the α phase, and the phase boundary and the γ phase corrosion resistance when the γ phase and the α phase are changed from the β phase to the α phase on the low temperature side are improved. When these effects are exerted, the value of the compositional relationship f3 = [Ni] / [Sb] is 0.3 or more, and 0.4 or more is preferable. 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 view of the saturation of the above effect.

(Metal phase) In order to ensure good hot workability, it is necessary to have a β phase at a hot working temperature. The β phase formed at a high temperature heating temperature or processing temperature becomes an α phase or a γ phase as the temperature decreases. Although it is based on the manufacturing process, even if it is the composition of the alloy of this invention, the β phase which has a problem of residual corrosion resistance exists, and the γ phase is produced. The compositional relationship f2=[Sb]/[Sn] and the compositional relationship f3=[Ni]/[Sb] are appropriate, and the Sn, Sb, and Ni are contained, thereby improving the corrosion resistance of the β phase and the γ phase. Therefore, there is no problem under normal water quality, but it cannot be said to be sufficient in a harsh environment.

That is, the ratio of the β phase to the γ phase contained in the metal phase is more than 5% by area ratio, and if the length of each long side of the β phase or the γ phase exceeds 100 μm under the microscope observation of an arbitrary cross section, Can not withstand the corrosion resistance in harsh environments. The dezincification resistance of the β phase or the γ phase is relatively low compared to the α phase, and therefore, in the case where these are present in the metal phase, dezincification corrosion may be preferentially exhibited. That is, if the length of the long side exceeds 100 μm, the depth of dezincification corrosion sometimes exceeds 100 μm, which causes a problem in corrosion resistance. Therefore, the total ratio of the ratio of the β phase to the γ phase contained in the metal phase is required to be 0% or more and 5% or less in terms of area ratio, or the length of each long side of the β phase or the γ phase is 100 μm or less. When the total ratio of the ratio of the β phase to the γ phase is 0% or more and 5% or less in terms of the area ratio, the area ratio of the β phase is preferably 0% or more and 3% or less. The total ratio of the ratio of the β phase to the γ phase contained in the metal phase is 5% or less in terms of area ratio, and the length of each long side of the β phase or the γ phase is preferably 100 μm or less. The total ratio of the ratio of the β phase to the γ phase is 0% or more and 5% or less in terms of area ratio, and the area ratio of the β phase is 0% or more and 3% or less, and each long side of the β phase or the γ phase The length is preferably 100 μm or less.

Furthermore, the crystal grain boundary and phase boundary of the α phase and the β phase or the α phase and the γ phase which are problematic in the corrosion resistance in a harsh environment include the α phase which is in contact with the β phase at the time of high temperature heating. The phase boundary, the grain boundary, and the compositional relationship f2=[Sb]/[Sn] and the compositional relationship f3=[Ni]/[Sb] are contained in an appropriate manner to contain the aforementioned Sn, Sb, and Ni, thereby improving corrosion resistance. Sex, so that it can fully cope.

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

(Heat processing) In this hot working, hot extrusion or hot forging is performed at a temperature of 670 ° C or more and 820 ° C or less, and an average cooling rate of 620 ° C to 450 is performed at 2 ° C / min or more and 200 ° C / min or less. It is preferred to carry out cooling in a temperature range of °C. The material that has been subjected to hot working is finally set to 100 ° C or lower, and is mostly 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. Therefore, the hot working temperature (hot extrusion temperature and hot forging temperature) is preferably 820 ° C or lower, and preferably 800 ° 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. Although it is also based on the processing equipment capacity, for example, when manufacturing a small-sized thin rod (less than 12 mm in diameter), it is difficult to extrude, or even if it can be extruded, it may not be completely extruded as the temperature in the process is lowered. There is thus a possibility that the weight ratio from the ingot to the product, that is, the yield, is deteriorated. Further, in the forged product having a high processing ratio, there is a possibility that the material cannot be sufficiently filled and cannot be molded.

Moreover, if the cooling rate after hot working is too fast, the phase transition from the β phase to the α phase is insufficient, and the β phase ratio after cooling becomes high. Further, the elongated β phase is liable to remain, and the corrosion resistance in a severe environment is deteriorated. Therefore, it is possible to cool the temperature region of 620 ° C to 450 ° C at an average cooling rate of 200 ° C / min or less, preferably 100 ° C / min or less. Regarding the lower limit of the cooling rate, if it is necessary to describe it, the production efficiency is considered to be 2 ° C / min or more.

In the case where the β phase changes to the γ phase and the α phase during cooling, the γ phase is easily elongated when the β phase is elongated, and the corrosion resistance is also deteriorated in a severe environment. In particular, hot extruded rods are obtained by extrusion from an ingot. The metallurgical phase of the hot extruded rod is arranged in parallel with the extrusion direction and is easily elongated. On the other hand, regarding the hot forged product, a hot extruded material obtained by extruding from an ingot is used as a raw material and hot forged. In hot forging, the material flows plastically in various directions in the mold by the shape of the product, but basically becomes a metal phase that follows the flow of the material. The hot extruded material is heated and hot forged, but the plastic deformation is in accordance with the shape of the forged die, and the metallographic phase of the heated hot extruded rod is destroyed, so that there is almost no crystal grain which is hot extruded than the raw material. The situation of large materials. As described above, since the Pb particles hardly dissolve in the copper alloy, they exist as metal Pb particles, regardless of the intragranular and grain boundaries. Therefore, in the heat processing or the heat treatment described later, when the melting point of Pb is 327 ° C or more, Pb is in a liquid state. The size (average crystal grain size) and distribution (density of the number) of the Pb particles also change by the temperature of the hot working, the flow of the metal phase, and the cooling rate. These are also the same in the heat treatment described later.

(Heat Treatment) When the heat treatment is performed after the hot working, the heat treatment temperature is 470 ° C or higher and 560 ° C or lower, and the holding time at the heat treatment temperature is preferably 1 minute or longer and 8 hours or shorter. In order to further improve corrosion resistance, heat treatment is an effective means. However, when the heat treatment temperature exceeds 560 ° C, the decrease in the β phase (phase transition from the β phase to the α phase) has no effect, and the β phase increases, which causes a problem in corrosion resistance. Therefore, the upper limit of the heat treatment temperature is 560 ° C or lower, and preferably 550 ° C or lower. On the other hand, when the heat treatment is performed at a temperature lower than the heat treatment temperature of 470 ° C, the β phase is decreased, but the γ phase is increased, and depending on the case, the corrosion resistance may be deteriorated. Therefore, the lower limit of the heat treatment temperature is 470 ° C or higher, and preferably 490 ° C or higher.

Further, if the holding time at the heat treatment temperature is less 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, which causes a problem in energy use. Therefore, in the present embodiment, the holding time at the heat treatment temperature is set to 1 minute or longer and 8 hours or shorter. Further, although hot forging is performed on a hot extruded material (forged raw material), even if the forged bar is subjected to heat treatment, it does not greatly affect the forgeability. This is because the forged material is heated prior to hot forging, so the heat treatment record is also removed. However, in order to carry out heat treatment, a cost is required. Therefore, a material for the hot forged brass alloy is usually used in an extruded state (heat treatment is not performed).

According to the above manufacturing method, the brass alloy hot-worked products of the first and second embodiments are produced.

As described above, the brass alloy hot-worked products according to the first and second embodiments of the present invention are excellent in corrosion resistance and are excellent in hot workability and machinability. Because of these characteristics, it is a preferred raw material for water supply pipe fittings such as metal parts, joints, and valves that are excellent in cost performance.

The embodiment of the present invention has been described above, but the present invention is not limited thereto, and can be appropriately changed without departing from the technical scope of the invention. [Examples]

Hereinafter, the results of the confirmation experiment performed to confirm the effects of the present invention are shown. In addition, the following examples are used for explaining the effects of the present invention, and the structures, processes, and conditions described in the examples are not intended to limit the technical scope of the present invention. Further, hereinafter, in the evaluation results, the symbol "◎" means "excellent", and the symbol "○" means "good". The symbol "△" means "fair", the symbol "x" means "poor", and the symbol "xxx" means "very poor."

The brass alloy hot-worked product of the first and second embodiments of the present invention and the comparative composition blank were produced. The composition of the copper alloy is shown in Tables 1-3. Further, the billet of the composition shown in Table 1 was produced using a commercial melting furnace and a casting machine. Specifically, the copper alloy molten metal is melted by a low frequency induction furnace so as to be a predetermined component, and a billet having a diameter of 240 mm is produced by a semi-continuous casting machine. The blanks of the compositions shown in Tables 2 and 3 utilize the laboratory's small melting equipment manufacturer. Specifically, the copper alloy molten metal is smelted in a small-sized high-frequency melting furnace so as to be a predetermined component, and cast into a mold to produce a billet having a diameter of 100 mm and a length of 125 mm.

[Table 1]

[Table 2]

[table 3]

(Hot Extrusion Material) The billet of the composition shown in Table 1 was cut into a diameter of 240 mm × a length of 750 mm, and extruded into a diameter of 12 mm by a 2,750 ton indirect extruder. Further, the billet was heated by an induction heating furnace before extrusion, and set to the extrusion temperature shown in Table 4. The cooling rate of the extruded bar in the temperature range of 620 ° C to 450 ° C was taken as the condition shown in Table 4. Further, the temperature of the billet and the extruded bar was measured using a radiation thermometer. Further, the extruded product after the hot extrusion process was subjected to heat treatment under the conditions shown in Table 4.

(Hot forging material) The billet of the composition shown in Table 1 was cut into a diameter of 240 mm × a length of 750 mm, and extruded into a diameter of 20 mm by a 2,750 ton indirect extruder. Further, the billet was heated by an induction heating furnace before extrusion, and set to the extrusion temperature shown in Table 5. The cooling rate of the extruded bar in the temperature range of 620 ° C to 450 ° C was taken as the condition shown in Table 5. Again, 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 × a length of 30 mm and a sample was taken. The sample was heated to the temperature shown in Table 5, and a cylindrical sample was erected by a 200 ton friction press, and free forging was performed from a height of 30 mm to 12 mm (processing rate: 60%). The cooling rate of the forged material in the temperature range of 620 ° C to 450 ° C was taken as the condition shown in Table 5. The hot forged product was also cooled to room temperature (20 ° C).

(Laboratory Extrusion Material 1) When the above-mentioned hot extruded material was produced, a part of the billet having a diameter of 240 mm shown in Table 1 was cut, and then the surface was cut to have a diameter of 95 mm × a length of 120 mm. This was used as a blank for the production of laboratory extruded material 1. The billet was heated to the temperature shown in Table 6 using a Montfort furnace, and a hot extruded rod having a diameter of 20 mm was obtained by a 200 ton direct extruder. The cooling rate of the extruded bar in the temperature range of 620 ° C to 450 ° C was taken as the condition shown in Table 6. The extruded rod 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.

(Laboratory Extrusion Material 2) The surface of the blank of the composition shown in Tables 2 and 3 was subjected to a cutting process to have a diameter of 95 mm and a length of 120 mm. The billet was heated to the temperatures shown in Tables 7 and 8 using a Montfort furnace, and a hot extruded rod having a diameter of 20 mm was obtained by a 200 ton direct extruder. The cooling rate of the extruded bar in the temperature range of 620 ° C to 450 ° C was set as the conditions shown in Tables 7 and 8. The extruded rod 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 Tables 7 and 8.

(Laboratory Forging Material) The surface of the blank of the composition shown in Tables 2 and 3 was cut to have a diameter of 95 mm × a length of 120 mm. The billet was heated to a temperature shown in Tables 9 and 10 using a Montfort furnace, and a hot extruded rod having a diameter of 20 mm was obtained by a 200 ton direct extruder. The cooling rate of the extruded bar in the temperature range of 620 ° C to 450 ° C was as shown in Tables 9 and 10. The extruded rod was cooled to room temperature (20 ° C). The obtained hot extruded material was cut into a cylindrical shape having a diameter of 20 mm × a length of 30 mm and a sample was taken. The sample was heated to the temperatures shown in Tables 9 and 10, and a cylindrical sample was erected by a 200-ton friction press, and free forging was performed 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 as shown in Tables 9 and 10. Furthermore, the hot forged product was cooled to room temperature (20 ° C). Further, the forged products after the hot forging process were subjected to heat treatment under the conditions shown in Tables 9 and 10.

The following hot workability was evaluated on the above hot extruded material, hot forged material, laboratory extruded material, and laboratory forged material.

(Hot Extrusion) In the hot extruded material, the portion which can be extruded at a diameter of 12 mm and which does not remain unextruded is set to "○", and the portion which is not extruded is set to "X". The crack confirmed on the surface of the hot extruded material was evaluated as "××". Furthermore, in the extrusion process which is actually carried out commercially, all ingots (blanks) are not extruded into a bar. When all of the extrusion is performed, defects are generated at the rear end portion of the extruded material which is the end portion of the ingot, and it is impossible to obtain a product. Therefore, an extrusion process is carried out by leaving a certain amount of the end portion of the ingot. The length of the remaining portion was set to 50 mm, and the case where the ingot exceeding 50 mm was left under the extrusion ability of the mass production machine was evaluated as "x". In the laboratory extruded material, in a hot extruded rod having a diameter of 20 mm, the extrusion length of 200 mm or more is evaluated as "○", and the less than 200 mm is evaluated as "X", which is confirmed on the surface of the hot extruded material. The cracker was evaluated as "××".

(Hot forgeability) A forging load of 100 tons or less is evaluated as "○", a forging load of more than 100 tons is evaluated as "X", and a crack on the surface of the hot forged material is evaluated as "××". As forging property, "○" evaluation is required. When the forging load exceeds 100 tons, it is difficult to forge using a forging machine having a small power, and there is a possibility that a forged product having a complicated shape cannot be formed. Therefore, the hot forgeability is evaluated as "x".

[Table 4]

[table 5]

[Table 6]

[Table 7]

[Table 8]

[Table 9]

[Table 10]

The above-mentioned hot extruded material, hot forged material, laboratory extruded material, and laboratory forged material were evaluated for metallographic observation, corrosion resistance (dezincification corrosion test/immersion test), and machinability.

(Metal observation) As shown in Fig. 1, in the metallographic phase, about 1/4 of the diameter D is observed in the direction parallel to the extrusion direction with respect to the hot extruded material (from the surface to the 1/4 portion of the diameter D, that is, If the material is φ20 mm, the cross-sectional microstructure is 5 mm from the surface, and the material is φ 12 mm, which is the portion from the surface of 3 mm. As shown in Fig. 2, regarding the hot forged material, the cross-sectional microstructure at a quarter of the thickness from the surface, that is, 3 mm, was observed on the cross section cut in the diameter direction from the portion outside the center portion of 8 mm. Further, in the case of free forging from a height of 30 mm to 12 mm in hot forging, a disk shape having a diameter of about 32 mm is obtained. The observation sample was etched by a mixed etching liquid of 3 vol% hydrogen peroxide water and 3 vol% ammonia water, and the metal phase was observed at a magnification of 200 times using a metal microscope (EPIPHOTO 300 manufactured by NIKON CORPORATION).

Regarding the area ratio of the β phase and the γ phase, the observed metal phase is binarized by image processing software (WinRoof), and the ratio of the area of the β phase and the γ phase to the area of the entire metallographic phase observed is calculated. . Further, regarding the area ratio, the metal phase observed at a magnification of 200 times is enlarged to a size of 195 mm × 243 mm (the substantial magnification is 355 times), and the metal phase of any three viewing angles among the areas of 75 mm × 100 mm is measured. And set the average value of these. Regarding the three angles of view, the portions that do not overlap are measured separately. Regarding the binarization processing, the β phase and the γ phase portion are separately color-coded for the 75 mm × 100 mm portion, and the area in which the color has been distinguished is measured using image processing software, and the measurement is relative to the whole (75 mm × Each area ratio of the β phase and the γ phase of 100 mm). The size and distribution (density) of the Pb particles were measured by the following method. Regarding the size of the Pb particles, there was a case where the Pb particles were fine, and the metal phase was photographed at a magnification of 1000 times using a metal microscope, and the metal phase was expanded to 195 mm × 243 mm (the substantial magnification was 1775 times). In the non-overlapping three viewing angles (75 mm × 100 mm: substantially evaluated area 0.06 mm ² ) in the measurement viewing angle, the Pb particle portions are color-coded, and the area in which the color has been distinguished is measured using an image processing software. The average particle diameter was determined from the area of each Pb particle. Specifically, it is assumed that the Pb particles are a circle, and the diameter of the Pb particles is determined as the particle diameter from the respective measured areas. Then, the average value of the particle diameters of all the observed Pb particles was determined as the average particle diameter. Further, the distribution (density) of the Pb particles was measured as follows. The number of Pb particles was counted in the three viewing angles at which the average particle diameter of the Pb particles was determined. The number of Pb particles relative to the entire measured portion was determined and the number per 100 μm ² (10 μm × 10 μm) was calculated. Then, the average value of the three points is obtained as the distribution (density).

Regarding the maximum length of the long side of the β phase and the γ phase, the metallographic phase of any three viewing angles is binarized 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 length of the specific β phase and γ phase is obtained. The maximum value among the absolute maximum lengths of all the β phases and γ phases measured was set to the maximum length. In the case of a hot extruded material, there is a maximum length in a direction parallel to the extrusion direction, and in the case of a hot forged material, there is a maximum length in a direction parallel to the flow direction of the material 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 β phase ratio and the γ phase ratio are 0%), and the maximum length of the long side of the β phase and the γ phase is The case of 20 μm or more and less than 50 μm is suboptimal. When the maximum length of the long side of the β phase and the γ phase is 50 μm or more and 100 μm or less, there is no problem, and when the maximum length of the long side of the β phase and the γ phase exceeds 100 μm, from the viewpoint of corrosion resistance, There is a possibility of causing problems. The corrosion resistance of the β phase and the γ phase is inferior to that of α. Corrosion resistance is enhanced by the proper addition of Sn, Sb, Ni, but under severe conditions, there is a possibility of dezincification corrosion on the β phase and the γ phase, and from the viewpoint of corrosion resistance, the phases are not In the continuous direction, that is, the length in the longitudinal direction is short, and it is preferably 100 μm or less.

(Dezincification corrosion test) As a dezincification corrosion test, by ISO 6509-1 (Corrosion of metals and alloys - Determination of dezincification resistance of brass alloys - Part 1: Corrosion of metals and alloys-Determination of dezincification resistance of The dezincification corrosion test described in the copper alloys with zinc-Part 1: test method) evaluates the dezincification corrosion property of each brass alloy material. That is, the surface of the cross-sectional microstructure was observed to be exposed to a 1 vol% copper (II) chloride aqueous solution held at 75 ° C (the exposed area was set to 1 cm ² for masking), and immersed for 24 hours. Next, the cross-sectional microstructure was observed from the perpendicular direction to the exposed surface, and the deepest part of the dezincification corrosion in the entire exposed surface, that is, the maximum dezincification corrosion depth was measured.

The case where the maximum dezincification corrosion depth was less than 20 μm (including 0 μm, that is, the case where dezincification corrosion was not confirmed) was evaluated as “◎”, and the case where the maximum dezincification corrosion depth was 20 μm or more and less than 50 μm was 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 maximum dezincification corrosion depth was 100 μm or more as “×”. When the maximum dezincification corrosion depth is less than 100 μm, it is judged to have dezincification resistance. Therefore, when it is evaluated as "△" or more, it can be said that it has corrosion resistance (dezincification 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, and a chlorine residual concentration of 30 ppm and a pH of 6.8 were adjusted to prepare a test solution. A test piece having an exposed surface was prepared in the same manner as the ISO 6509 test. 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 ISO6509 test.

The case where the maximum dezincification corrosion depth was less than 20 μm (including 0 μm, that is, the case where dezincification corrosion was not confirmed) was evaluated as “◎”, and the case where the maximum dezincification corrosion depth was 20 μm or more and less than 50 μm was 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 maximum dezincification corrosion depth was 100 μm or more as “×”. In the immersion test, although it was not judged that there was a clear standard for dezincification resistance, similarly to the ISO6509 test, if the maximum dezincification corrosion depth was less than 100 μm, it was judged to have dezincification resistance. In any dezincification corrosion test, it is not necessary to say that the maximum dezincification corrosion depth is small and the corrosion resistance is good.

(Meatability) A hot extruded material having a diameter of 20 mm (without heat treatment) was prepared. A hole having a depth of 10 mm was opened to the center portion of the hot extruded material (bar) by a 3.5 mm diameter straight shank drill at a rotational speed of 1250 rpm and a feed rate of 0.17 mm/rev. The resistance value of the torque and the thrust applied to the drill at this time is measured, and the root mean square of the torque and the thrust, that is, the cutting resistance value is obtained. Based on the cutting resistance value of JIS H3250 C3604, the machinability index was obtained by the following formula, and the machinability was evaluated by this value. Machinability index (%) = (cutting resistance value of each brass alloy material) / (cutting resistance value of C3604) × 100 The machinability index is 90% or more and is evaluated as "◎", and the machinability index is 75% or more and less than 90% were evaluated as "○", and the machinability index was less than 75% as "X". If the machinability index is 75% or more, it is not too inferior to C3604 and can be industrially cut. Further, a bar having 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 (without heat treatment). 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 shank drill having a diameter of 3.5 mm, and the machinability of the hot forged material was evaluated. The results of various tests are shown in Tables 11 to 24.

[Table 11]

[Table 12]

[Table 13]

[Table 14]

[Table 15]

[Table 16]

[Table 17]

[Table 18]

[Table 19]

[Table 20]

[Table 21]

[Table 22]

[Table 23]

[Table 24]

In alloy No. S137 (test No. T137) in which the content of Cu was 61.2 mass%, although the extrudability was good, in the extruded material, the β phase ratio was 6%, and the total of the β phase and the γ phase ( β+γ) is 10%, the maximum length of β phase or γ phase is 150 μm, the ratio of β phase and γ phase is high, and the maximum length of β phase or γ phase is long, so corrosion resistance (dezincification resistance) Poor. Alloy No. S40 (test No. T40, T70) having a Cu content of 61.7 mass% and alloy No. S52 (test No. T52 and T82) having a Cu content of 61.8 mass%, although extrudability There is no problem, but in the extruded material, the β phase ratio is 3-4%, the total of the β phase and the γ phase (β+γ) is 5%, and the maximum length of the β phase or the γ phase is also longer. 90 to 95 μm. The corrosion resistance (dezincification resistance) was evaluated as Δ in the extruded material, the forged material, and the respective heat-treated materials, and although there was no problem in practical use, the corrosion resistance was slightly lower than that of the other alloys of the present invention.

Evaluation of extrudability or forgeability in Alloy No. S6 (Test No. T6, T16, T26) and Alloy No. S31 (Test No. T31, T61) in which the content of Cu was 64.1 mass% was high. There is no problem with "○", but sometimes there is a case where the extruder can be extruded to the maximum extent, and the deformation resistance at high temperature is large. Under the same extrusion conditions, the extrusion property is better than other ones. The alloy of the invention is slightly inferior. In alloy No. S136 (test No. T136) in which the content of Cu was set to 64.7 mass%, it was not possible to extrude (the portion which could not be completely extruded, and the extrusion length in the laboratory extruded material was less than 200 mm). There is a problem with production. However, the β phase and the γ phase are small, and the corrosion resistance is good.

In Alloy No. S144 (Test No. T144) in which the content of Pb is 0.55 mass%, other components are within the scope of the present invention, and there is no problem in hot workability and corrosion resistance such as extrudability (evaluation is Δ or more). , but the machinability is poor. With respect to this material, the Pb particles have an average particle diameter of 0.1 μm, a distribution (density) of 0.001/100 μm ² , a small size, a low density, and poor machinability (machinability). In Alloy No. S145 (Test No. T145) in which the content of Pb was 2.15 mass%, the other components were within the range, and there was no problem in hot workability, corrosion resistance, and machinability. However, if Pb is large, the amount of elution into water may increase, and it is necessary to carry out a treatment for reducing the amount of elution. With respect to this material, the Pb particles had an average particle diameter of 3.0 μm and a distribution (density) of more than 0.06 / 100 μm ² , and as described above, the amount of Pb eluted increased. When the content of Pb is within the range of the present invention, the machinability is evaluated as "?" or "○" and is excellent. The machinability is affected not only by the influence of Pb but also by the metallographic phase. Therefore, it is not possible to evaluate only the content of Pb, and it is evaluated as "◎", and a large number of samples are contained in an appropriate range. Regarding the average particle diameter and distribution (density) of the Pb particles, the conditions of the hot working (hot extrusion, hot forging) or the conditions of the heat treatment are somewhat affected. In Alloy No. S5, when the heat treatment temperature was 580 ° C (test No. T5-2), the average particle diameter of Pb exceeded 3 μm which caused a problem in the amount of elution. Further, when the hot extrusion temperature of the laboratory extruded material of Alloy No. S1 was 850 ° C (test No. T21-3), the average particle diameter of Pb was also more than 3 μm. In Alloy No. S37, S44 and S45, when the hot forging temperature is higher than 840 °C (test No. T67-3, T74-2, T75-3), surface cracks occur and hot workability exists. The problem was not investigated after the subsequent heat treatment. Moreover, in the same alloy, when the hot forging temperature is lower than 670 ° C (test No. T67-5, T74-3, T75-5), the deformation resistance is also high and the load during hot forging exceeds 100t. The subsequent heat treatment and the like were not investigated. Regarding these alloys, only the average particle diameter and distribution of the Pb particles were investigated. As a result, in the case of hot forging at 850 ° C (test No. T67-3) in Alloy No. S37, the Pb average particle diameter exceeded 3 μm. In the case of No. S44 and S45, when the hot forging temperature is 840 ° C (test No. T74-2, T75-3), the distribution of Pb is 0.001/100 μm ² , and the machinability (machinability) is poor. . In the alloy No. S44, when the hot forging temperature was 650 ° C (test No. T74-3), the average particle diameter of Pb was 0.1 μm, and the machinability (cuttability) was also inferior. When the average particle diameter and distribution of these Pbs are out of an appropriate range, problems occur in the machinability or the elution of Pb. When these are in an appropriate range, the evaluation of machinability (workability) is excellent without any problem.

In alloy No. S141 (test No. T141) in which the content of Sn is 0.45 mass%, if the other composition is within an appropriate range, there is no problem as extrudability or metal phase, but in the immersion test, it is evaluated as ×. The result of poor corrosion resistance. In Alloy No. S142 (Test No. T142) in which the content of Sn was set to 1.10 mass%, the γ phase ratio increased, and the total (β + γ) of the β phase and the γ phase exceeded 5%. Therefore, the corrosion resistance is inferior, and the corrosion resistance is maintained poor even when heat treatment is performed.

In addition, Sn is also different in the content of other elements. However, in alloy No. S46 (test No. T46 and T76) in which the content of Sn is 0.57 mass%, Δ is more in the evaluation of corrosion resistance (it is judged to be actually used). There is no problem and there is corrosion resistance. If the content of Sn is small, the corrosion resistance tends to be deteriorated. On the other hand, when the content of Sn is large, the γ phase tends to be large, but there is no problem in the range of the present invention. In Alloy No. S49 (Test No. T49, T79) in which the content of Sn was 0.96 mass%, the γ phase of the hot extruded material or the hot forged material was large, and Δ was also evaluated in the corrosion resistance evaluation. As described above, although the corrosion resistance is improved by the content of Sn, if it exceeds the appropriate range, the γ phase changes in the metal phase, and the corrosion resistance is rather deteriorated.

In Alloy No. S140 (Test No. T140) in which the content of Ni was set to 0.018 mass%, other elements were in an appropriate range, but the corrosion resistance was inferior. Alloy No. S41 (test No. T41, T71) in which the content of Ni was set to 0.021 mass%, and the composition relational expression f3 = [Ni] / [Sb] was also low, but Δ was more in the evaluation of corrosion resistance. In particular, the evaluation of the immersion test was Δ, and although it was a material having corrosion resistance, it was a slightly inferior result in the alloy of the present invention. In Alloy No. S146 (Test No. T146) having a Ni content of 0.11 mass% and a range higher than the range of the present invention, there is no problem in hot extrudability or corrosion resistance, but the amount of Ni eluting water is increased. Not good. Although the content or compositional relationship of other elements is also used, when the content of Ni is increased, ○ is also increased in corrosion resistance evaluation, and corrosion resistance is improved.

In the alloy No. S143 (test No. T143) in which the content of Sb is set to 0.015 mass%, and the alloy No. S138 (test No. T138) in which the content of Sb is set to 0.018 mass%, the content of Sb is larger than the range of the present invention. Less, corrosion resistance is poor. In alloy No. S34 (test No. T34, T64) in which the content of Sb was set to 0.024 mass%, and alloy No. S43 (test No. T43 and T73) in which the content of Sb was set to 0.028 mass%, corrosion resistance was evaluated. There are many Δ, and the corrosion resistance has no problem in practical use, but it is known that Sb has an influence on corrosion resistance. On the other hand, in Alloy No. S139 (Test No. T139) in which the content of Sb is set to 0.085 mass%, since the content of Sb is large, the corrosion resistance is good, but hot workability such as cracking during hot extrusion is inferior. If Sb is within the scope of the present invention, it is also affected by the content or compositional relationship of other added elements, but the corrosion resistance becomes good.

P, Mn or Fe is an unavoidable impurity, but if it is within the range shown in the examples, it does not greatly affect hot workability, corrosion resistance and the like. In Alloy No. S5 (Test Nos. T5-1 to 11, T15) having a P content of 0.02 mass% or less, there was no problem in castability and hot workability (extrudability, forgeability). On the other hand, in Alloy No. S7 (Test No. T7, T17) in which the content of P was 0.026 mass%, cracks occurred during hot working (hot extrusion, hot forging).

In alloy No. S101 (test No. T101) having a compositional expression f1 of 60.32, there was no problem in hot workability, but there were many β phase and γ phase, and the maximum length was also long, and as a result, corrosion resistance was inferior. In alloy No. S56 (test No. T56, T86) having a compositional relationship f1 of 60.63, β and γ phases were many, but the corrosion resistance was evaluated as Δ. In alloy No. S135 (test No. T135) having a compositional expression f1 of 64.09, the β phase and the γ phase are small, and the corrosion resistance is also good. However, cracking occurs during extrusion, and there is a problem in hot workability.

In alloy No. S35 (test No. T35 and T65) having a compositional relationship f1 of 63.65, the β phase and the γ phase were also small and the corrosion resistance was also good. Further, regarding the hot workability, the extrusion length is 200 mm or more in laboratory extrusion, but it is slightly shorter than other alloys of the present invention, and is close to the limit of hot workability. When the numerical value of the relational expression f1 is within an appropriate range, it is affected by other elements and the like, but the evaluation of corrosion resistance tends to be good. As described above, the compositional relationship f1 is related to hot workability and corrosion resistance, and is important in the range of the present invention.

In alloy No. S133 (test No. T133) having a compositional relationship f2 of 0.026, the content of each element is within an appropriate range, but the corrosion resistance is poor, and the β phase and the γ phase are preferentially subjected to dezincification corrosion or the like. Also larger. Furthermore, there is no problem with hot workability. On the other hand, in alloy No. S134 (test No. T134) having a compositional relationship f2 of 0.132, although corrosion resistance was good, cracks occurred during hot extrusion, and the like, there was a problem in hot workability.

In alloy No. S53 (test No. T53, T83) having a compositional relationship f2 of 0.033, there was no problem in hot extrudability, and in the dezincification corrosion test of ISO 6509, the heat-treated material was also evaluated, but in the impregnation. In the test, the evaluation was Δ, and even if the heat treatment was performed, the corrosion resistance was less improved. In alloy No. S42 (test No. T42, T72) having a compositional relationship f2 of 0.11 and alloy No. S55 (test No. T55 and T85) having a compositional relationship f2 of 0.105, the corrosion resistance was also good. By performing the heat treatment, the corrosion resistance was evaluated to be ○ or more without problems. However, although the crack on the surface of the extrusion front end portion was not confirmed, there were irregularities, and it was found that the crack was close to the limit of occurrence of cracks. In addition, if the compositional relationship f2 is within an appropriate range, hot workability or corrosion resistance is also good. Of course, as described above, the compositional relationship f2 has a large influence on hot workability or corrosion resistance, but each characteristic is affected by other compositional relationships and added elements.

In alloy No. S132 (test No. T132) having a compositional relationship f3 of 0.28, the content of the additive element is within the appropriate range of the present application, but the corrosion resistance is inferior. It is considered that since the value of the compositional relationship f3 is small, the effects of Ni and Sb on the corrosion resistance are low. In the alloy No. S54 (test No. T54, T84) in which the compositional relationship f3 was set to 0.38, the corrosion resistance of the immersion test was evaluated to be Δ and slightly lower, but it was judged to have the level of corrosion resistance. If the compositional relationship f3 is within an appropriate range, it may be affected by the content of other elements or other compositional relationships, but exhibits good corrosion resistance.

In Alloy No. S143 (Test No. T143) having a compositional relationship f3 of 3.73, the content of Sb was low and the corrosion resistance was inferior. In the case of the content of Ni and Sb, if Sb is, for example, 0.03 mass%, which is the lower limit of the preferred range, the content of Ni becomes 0.105 mass% when [Ni]/[Sb]=3.5 or more. The upper limit of the appropriate range of the applied Ni. As described above, when the value of the relation f3 is large, the amount of Ni is large, and there is a possibility that there is a problem in the elution amount of Ni, or Sb is low and there is a problem in corrosion resistance. Therefore, 3.5 is made the upper limit.

Next, refer to Test No. 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, and T75-1. T75-6, confirm the hot working conditions. When the temperature condition at the time of hot working (hot extrusion, hot forging) is 840 ° C or 850 ° C and the temperature is high, cracks are generated in the extruded material, surface cracks are generated in the forged product, and deformation ability at high temperature is obtained. Getting worse. Further, in Test No. T21-3 or T67-3, the average particle diameter of Pb was increased under conditions of high temperature during hot working, and the amount of elution of Pb was also increased to cause an adverse effect. On the contrary, in the case of hot working (hot extrusion, hot forging), the temperature condition is 640 ° C or 650 ° C, and in the case of low temperature, it cannot be extruded (the extrusion length of the laboratory extruded material becomes less than 200 mm) or forging in forging When the load is increased, the deformation resistance of the material at a high temperature is increased, and the hot workability is lowered. In the case where the hot extrusion temperature of Test No. T21-5 is 640 ° C, the particle diameter of Pb is also small, and the distribution exceeds 0.06 / 100 μm ² . In this case, problems occur in the amount of Pb eluted. . Thus, 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 the particle size and distribution of Pb.

After hot working (hot extrusion, hot forging), the cooling rate in the temperature range of 620 ° C to 450 ° C exceeds 200 ° C / min (test No. T5-11, T21-7), due to β phase More, the maximum length is also longer, etc., and the corrosion resistance is poor. On the other hand, when the cooling rate is less than 2 ° C /min, the temperature is not more than 2 ° C / min. However, for example, if it is 1 ° C / min, the cooling time is 170 minutes, which causes problems such as obstacles to mass productivity.

Next, the test conditions No. T5-1 to T5-10 and T12-1 to T12-7 were examined, and the heat treatment conditions were confirmed. If the heat treatment conditions of the hot extruded material and the hot forged product exceed 560 ° C, the β phase is large, and the maximum length is also long, and the corrosion resistance is poor. When the heat treatment conditions of the hot extruded material and the hot forged product are lower than 470 ° C, the γ phase changes more, the maximum length is longer, and the corrosion resistance is deteriorated compared to other conditions. Under the condition that the holding time was less than 1 minute, the effect of the heat treatment could not be seen as in the state at the time of extrusion. 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 increased.

As described above, in the alloy of the present invention in which the content of each additive element and the compositional relationship are in an appropriate range, the hot workability (hot extrusion, hot forging) is excellent, and the corrosion resistance and the machinability are also good. Moreover, in order to obtain excellent characteristics in the alloy of the present invention, it can be achieved by setting the production conditions in hot extrusion and hot forging and the conditions in the heat treatment to an appropriate range. [Industrial availability]

The brass alloy hot-worked product of the present invention is excellent in hot workability (hot extrudability and hot forgeability), and is excellent in corrosion resistance and machinability. Therefore, the brass alloy hot-worked product of the present invention can be preferably applied as a structural material of a water supply pipe metal fitting, a joint, a valve, and the like for a water pipe.

D‧‧‧diameter

Fig. 1 is an explanatory view showing a metallographic observation position of a hot extruded material in the embodiment. Fig. 2 is an explanatory view showing a metallographic observation position of the hot forged material in the embodiment.

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Claims (8)

A brass alloy hot-worked product comprising Cu: 61.5 mass% or more and 64.5 mass% or less, Pb: 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 includes Zn and unavoidable impurities, and the content of the impurity P is inevitably 0.02 mass% or less; the content of Cu is set to [Cu]mass%, the content of Pb is [Pb]mass%, the content of Sn is [Sn]mass%, the content of Sb is [Sb]mass%, and the content of Ni is [Ni In the case of mass%, the satisfaction is as follows: 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; the metallographic phase is an α phase base, and includes Pb particles. The total area ratio of the area ratio of the β phase to the area ratio of the γ phase is 0% or more and 5% or less, and the length of each long side of the β phase or the γ phase is 100 μm or less. A brass alloy hot-worked product comprising: 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, and 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, the balance includes Zn and unavoidable impurities, and the content of the impurity P is inevitably 0.02 mass% or less; the content of Cu is set to [Cu]mass%, the content of Pb is [Pb]mass%, the content of Sn is [Sn]mass%, the content of Sb is [Sb]mass%, and the content of Ni is [Ni In the case of mass%, the satisfaction is as follows: 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; the metallographic phase is an α phase base, and includes Pb particles. The total area ratio of the area ratio of the β phase to the area ratio of the γ phase is 0% or more and 5% or less, and the length of each long side of the β phase or the γ phase is 100 μm or less. The brass alloy hot-worked product according to claim 1 or 2, wherein the Pb particles have an average particle diameter of 0.2 μm or more and 3 μm or less. The brass alloy hot-worked product according to claim 1 or 2, wherein the distribution of the Pb particles is 0.002 / 100 μm ² or more and 0.06 / 100 μm ² or less. The brass alloy hot-worked product according to claim 1 or 2, wherein the Pb particles have an average particle diameter of 0.2 μm or more and 3 μm or less, and the Pb particles have a distribution of 0.002 / 100 μm ² or more and 0.06 / 100 μm ² the following. A brass alloy hot worked article according to claim 1 or 2, which is used as an appliance for a water pipe. A method for producing a brass alloy hot-worked article, wherein the brass alloy hot-worked product according to any one of claims 1 to 6, wherein the manufacturing method is characterized by being at a temperature of 670 ° C or higher and 820 ° C or lower The hot working is performed, and the temperature region of 620 ° C to 450 ° C is cooled at an average cooling rate of 200 ° C / min or less. The method for producing a brass alloy hot-worked product according to claim 7, wherein after the hot working, the heat treatment is maintained at a temperature of 470 ° C or higher and 560 ° C or lower for 1 minute or longer and 8 hours or shorter.