JP5566622B2 - Cast alloy and wetted parts using the alloy - Google Patents

Description

In particular, the present invention satisfies the basic characteristics such as castability and erosion / corrosion resistance, and preferably can provide good dezincing resistance without heat treatment. brass alloys use and related wetted parts using the alloy.

  It is known that a mold casting has a high cooling rate at the time of casting, so that a casting with few surface defects and a good appearance can be obtained, and a thin casting with a dense metal structure and strength can be obtained. For this reason, die casting is suitable for forming wetted parts such as main parts such as water supply taps and pipe joints, and brass alloys are often used as the material for wetted parts.

By the way, in the wetted parts made of brass, Zn in the copper alloy is easily eluted into the fluid due to the difference in ionization tendency between Cu and Zn, and the Zn content decreases with the passage of time. For this reason, for example, when the applied fluid is water or the like, such as valves and plugs, it is important to prevent the phenomenon of dezincification corrosion.
Further, in particular, corrosion is likely to occur in a combination portion of different metals in the connection portion of the valve / plugs, and erosion is likely to occur in the valve seat portion due to the high-speed fluid. For these reasons, copper-free products and casting materials used for faucet fittings and the like are required to have dezincing resistance and erosion / corrosion resistance.

Therefore, at the time of molding the wetted parts made of brass, it is effective to increase the α phase ratio without crystallizing the β phase that is easily dezinced as much as possible in order to improve the dezincing resistance. In this case, as means for increasing the α phase ratio, for example, increasing the amount of Cu is effective, and in order to further increase the α phase ratio, heat treatment is performed at 450 to 550 ° C. for 30 minutes or more. It is also effective. In addition, in order to improve dezincing resistance, addition of elements such as P, Sb, As, and Sn is also an effective means.
On the other hand, in order to improve the erosion / corrosion resistance, for example, it is also known that 0.2% or more of Sn is added or 2% or more of Al is added.
In addition, when castings are provided, material properties such as molten metal flow, cast cracking resistance, good casting surface quality, and difficulty in forming shrinkage cavities are also necessary, and it is also necessary to mold in consideration of these. .

  As this type of casting brass casting, for example, there is a copper-based alloy of Patent Document 1. This copper-based alloy contains Cu: 61.0-65.0% by weight and Sn: 0.8-3.5% by weight, and has excellent machinability, mechanical properties, and corrosion resistance. It has a composition balance that improves erosion / corrosion resistance and casting crack resistance.

  The lead-free corrosion-resistant brass alloy in Patent Document 2 is Cu: 64.0-68.0%, Sn: 0.3-1.0%, Ni: 0.5-1.0%, Al: It contains 0.4 to 0.8%, Bi: 1.0 to 2.0%, and the balance consists of impurities and zinc. The literature 2 is a brass material that aims to improve the dezincing resistance in addition to the machinability and the grindability as plating pretreatment. For example, the metal structure is refined by containing B. Thus, it is described that the dezincing resistance is improved without heat treatment.

  The copper-based alloy for casting of Patent Document 3 is Cu: 60.0-65.0%, Pb: 1.5-2.4%, Sn: 0.5-1.2%, Al: 0 on a weight basis. 0.5 to 1.2%, Ni: 0.5 to 1.2%, B: 4 to 12 ppm, and the balance substantially consists of Zn. In the same document 3, the dezincification resistance is secured by crystallization of the α phase accompanying the increase of Cu and the inclusion of Sn and Ni, and further the dezincification resistance is improved by growing the α phase by heat treatment. It is said. Further, Al is trying to improve the fluidity of the molten metal. In this copper-based alloy, B is contained in order to refine crystal grains and reduce casting cracks.

JP 2005-281800 A JP 2000-239765 A JP-A-9-176762

However, in the above copper alloys, if the content of Cu or Sn is increased in order to improve the dezincing resistance and erosion / corrosion resistance, the hot-water flow at the time of casting is lowered, and the hot water is poor. It was easy to produce a casting defect. This casting defect cannot be improved even if Sb having the property of improving the dezincing resistance is contained.
For example, in Patent Document 1, in order to improve dezincing resistance and erosion / corrosion resistance, it is difficult to prevent casting defects only by increasing Cu, Sn, and the like.

  Moreover, the brass material of patent document 2 is going to improve machinability, grindability as a plating pretreatment, and dezincing resistance. However, this brass alloy does not take into consideration any improvement in erosion and corrosion resistance and suppression of casting defects such as poor hot water. In addition, this brass material has a particularly high Cu content ratio, and this has caused hot water defects to occur more easily.

On the other hand, although the copper-based alloy for casting of Patent Document 3 is intended to ensure dezincing resistance and castability such as molten metal flow, there is no description at all about improving erosion / corrosion resistance. Absent. Moreover, although B contains in order to reduce a casting crack in the same literature 3, it is not described that this B exhibits effects other than a casting crack.
Furthermore, this copper-based alloy is intended to improve the dezincing resistance by applying a heat treatment, but when it undergoes a heat treatment step, there will be a burden on the manufacturing process and a cost increase due to the generation of heat treatment costs. There is.

The present invention has been developed as a result of intensive studies in view of the above-described circumstances, and the object of the present invention is casting while improving dezincing resistance and erosion / corrosion resistance without requiring heat treatment. can be molded, moreover, provides a wetted components using casting brass alloy and its alloys to improve the castability, such as fluidity, etc. for die casting soundness can be secured as a casting There is.

In order to achieve the above object, the invention according to claim 1 ensures the erosion and corrosion resistance by containing Sn in a mass ratio of 0.8 to 2.0%, and further, Sb is 0.04. By containing ~ 0.15%, dezincing resistance is improved, and by making Cu 61.2 ≦ Cu <64.0%, hot water flowability is improved while also ensuring dezincing resistance. Moreover, hot metal flowability is improved by containing 0.4 to 0.7% of Al. Furthermore, by containing 1 to 200 ppm of B, which has the effect of refining the macro crystal grains, the area ratio of the γ phase is increased to 2.8% or more by refining the crystal grains and the ISO maximum dezincification corrosion depth is secured to 200 μm or less. It is a brass casting alloy for casting having a compositional balance excellent in hot-water flow property and erosion / corrosion resistance . Moreover, this brass alloy contains 0.5 to 3.0% of Pb , the remainder Zn and inevitable impurities as components other than the above.

The invention according to claim 2 ensures the erosion / corrosion resistance by containing Sn in a mass ratio of 0.8 to 2.0%, and further contains 0.04 to 0.15% of Sb. The dezincing resistance is improved, and by making Cu 61.2 ≦ Cu <64.0%, the hot-water flowability is improved while ensuring the same dezincing resistance. Moreover, hot metal flowability is improved by containing 0.4 to 0.7% of Al. Furthermore, by containing 1 to 200 ppm of B, which has the effect of refining the macro crystal grains, the area ratio of the γ phase is increased to 2.8% or more by refining the crystal grains and the ISO maximum dezincification corrosion depth is secured to 200 μm or less. It is a brass casting alloy for casting having a compositional balance excellent in hot-water flow property and erosion / corrosion resistance. Moreover, this brass alloy contains Bi 0.5 to 2.5%, the remainder Zn and inevitable impurities as components other than the above.

In the invention according to claim 3 , the erosion and corrosion resistance is ensured by containing Sn in a mass ratio of 0.8 to 2.0%, and further Sb is contained in an amount of 0.04 to 0.15%. The dezincing resistance is improved, and by making Cu 61.2 ≦ Cu <64.0%, the hot-water flowability is improved while ensuring the same dezincing resistance. Moreover, hot metal flowability is improved by containing 0.4 to 0.7% of Al. Furthermore, by containing 1 to 200 ppm of B which has the effect of refining the macro crystal grains, the ISO maximum dezincification corrosion depth is ensured to be 200 μm or less by surrounding the β phase with the γ phase. It is a brass casting alloy for casting having an excellent composition balance in corrosion characteristics. Moreover, this brass alloy contains 0.5 to 3.0% of Pb, the balance Zn and inevitable impurities as components other than the above.

In the invention according to claim 4 , the erosion and corrosion resistance is ensured by containing Sn in a mass ratio of 0.8 to 2.0%, and further Sb is contained in an amount of 0.04 to 0.15%. Thus, dezincing resistance is improved, and by making Cu 61.2 ≦ Cu <64.0%, the hot-water flowability is improved while also ensuring dezincing resistance. Moreover, hot metal flowability is improved by containing 0.4 to 0.7% of Al. Furthermore, by containing 1 to 200 ppm of B which has the effect of refining the macro crystal grains, the ISO maximum dezincification corrosion depth is ensured to be 200 μm or less by surrounding the β phase with the γ phase. It is a brass casting alloy for casting having an excellent composition balance in corrosion characteristics. Moreover, this brass alloy contains Bi 0.5 to 2.5%, the remainder Zn and inevitable impurities as components other than the above.

The invention according to claim 5 is the copper alloy according to any one of claims 1 to 7, and contains 0.04 to 0.4% of Fe that assists in refining macrocrystal grains of B. By doing so, it is a brass alloy for casting in which the content of expensive B is reduced to 1 to 30 ppm .

The invention according to claim 6 improves the dezincing resistance by containing 0.2 to 1.0% of Ni.

The invention according to claim 7 is a wetted part processed and formed using the cast alloy according to any one of claims 1 to 6.

The invention according to claim 8 is a cast alloy according to any one of claims 1 to 6 were prepared by a die casting.

The invention according to claim 9 is the wetted parts made of Casting alloy according to claim 8.

According to the present invention, it is possible to perform casting while improving dezincing resistance and erosion / corrosion resistance without the need for heat treatment, and also improve castability such as hot water flow and casting crack resistance. The brass alloy for casting which can ensure the soundness as a casting can be provided. Moreover, it is also possible to mold the various casting, for example, even when molded by sand casting, a Zogo gold cast can exhibit material properties excellent as in the case of molding by die casting.

Moreover , it can be formed by casting such as die casting while improving dezincing resistance and erosion / corrosion resistance without the need for heat treatment, and refinement of the metal structure while improving molten metal flowability. It is a brass alloy for casting that can produce a casting with a fine casting surface. In particular, with regard to dezincing resistance, it is a brass alloy for casting that can dramatically improve its characteristics by suppressing the progress of corrosion.
Moreover, Pb-containing, or even for any Pb-less, it is Zogo gold cast macro grains can be improved dezincification resistance is miniaturized.

Furthermore , a brass alloy for casting that can be molded by casting such as mold casting while improving dezincing resistance and erosion / corrosion resistance without requiring heat treatment, and can improve the flowability of molten metal. It is. In particular, for the dezincing resistance, by increasing the area ratio of the γ phase is Zogo gold casting can be suppressed reliably ISO maximum dezincification corrosion depth.
Moreover, Pb-containing, or even for any Pb-less, it is Zogo gold cast macro grains can be improved dezincification resistance is miniaturized.

Also , a brass alloy for casting that can be formed by casting such as mold casting while improving dezincing resistance and erosion / corrosion resistance without requiring heat treatment, and can improve the flowability of molten metal. It is. In particular, for dezincification resistance, which is Zogo gold casting can be suppressed reliably ISO maximum dezincification corrosion depth by surrounding the dezincification easily β phase at γ phase.
Moreover, Pb-containing, or even for any Pb-less, it is Zogo gold cast macro grains can be improved dezincification resistance is miniaturized.

Further , by assisting the refinement of macro crystal grains by B, it is possible to suppress the content of expensive B compared to other components, and to manufacture at a low cost while ensuring a predetermined dezincing resistance. it is Zogo gold cast can.

Furthermore, it has excellent castability such as molten metal flow and cast cracking resistance while ensuring excellent dezincing resistance and erosion / corrosion resistance without requiring heat treatment. Alloying can be provided.

Moreover , it is a wetted part that can exhibit excellent castability such as hot-water flow and cast cracking resistance while ensuring excellent dezincing resistance and erosion / corrosion resistance without requiring heat treatment. Valve parts such as drinking water valves, stems, valve seats, discs, plumbing equipment such as faucets and fittings, equipment for water supply and drainage pipes, wetted strainers, pumps, motors and other equipment, faucet fittings, water heaters A wide variety of wetted parts such as hot water-related devices, parts such as water supply lines, members, etc., final products, assemblies, etc., and intermediate products such as coils and hollow bars can be provided.

Further, the casting soul or the wetted part can be manufactured by die casting.

It is explanatory drawing which showed the manufacturing method of a test material. It is the schematic diagram which showed the metal mold | die for test material shaping | molding. It is the graph which showed the relationship between Cu amount and ISO maximum dezincing depth. It is the external view which showed the test material which consists of a water stop cock. (A) is front sectional drawing of a test material. (B) is a bottom view of the specimen. (C) is a side view of the specimen. It is the external view which showed the test material which consists of a mixing faucet. (A) is a partially cutaway front view of the test material. (B) is a plan view of the specimen. (C) is AA sectional drawing of (a). It is the schematic explanatory drawing which showed the crevice jet corrosion test apparatus. It is the schematic diagram which showed the test material for an erosion-proof / corrosion test. It is the microscope picture which showed the structure | tissue where a macrocrystal grain is coarse. It is the microscope picture which showed the structure | tissue where a macrocrystal grain is fine. It is the graph which showed the relationship between B content, macrocrystal grain refinement | miniaturization, and the maximum dezincing depth at the time of melt | dissolving with a molten metal coating | covering material by air release. It is the graph which showed the relationship between B content, macrocrystal grain refinement | miniaturization, and the maximum dezincing depth at the time of melt | dissolving by air release. The macro structure of the alloy in which the macro crystal grain in the present invention is refined, and the alloy in which the macro crystal grain is not refined as a comparative example, its schematic diagram, and the microstructure are shown. It is the partially expanded sectional view which expanded the dezincification corrosion part before and behind crystal grain refinement | miniaturization of FIG. (A) is a partially expanded sectional view without crystal grain refinement. (B) is a partially expanded sectional view with crystal grain refinement. (A) is plane explanatory drawing which shows the test method of a vortex test, (b) is AA sectional drawing of (a). It is a graph which shows the relationship between Cu content and hot water flow length. It is a graph which shows the dezincing-proof test result with respect to content of Sn and Sb.

  The brass alloy for casting according to the present invention contains B and Fe in addition to containing Sb while increasing the Cu content while ensuring erosion / corrosion resistance by the inclusion of Sn. By improving the dezincing resistance to a level satisfying the ISO maximum dezincification corrosion depth of 200 μm or less without performing a heat treatment, it contains B and suppresses poor hot water supply. Brass alloy with improved soundness. Below, the example of the ingot or wetted part using the brass alloy for casting in this invention and its alloy is demonstrated.

As an example of the brass alloy for casting, for example, in mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8 to 2.0%, Sb: 0.04 to 0.15%, Al: 0 4 to 0.7%, Bi: 0.5 to 2.5%, or Pb: 0.5 to 3.0%, at least one of B: 1 to 200 ppm, the balance Zn and inevitable impurities Containing. This brass alloy has a compositional balance excellent in dezincing resistance, erosion / corrosion resistance, hot water flow resistance, and casting crack resistance by refining macro crystal grains and forming an α + β + γ structure.
This brass alloy is suitable for molding by die casting, but can also be used for castings other than die casting such as sand casting.

Examples of other brass alloys for casting include, for example, 61.2 ≦ Cu <64.0% in mass ratio, Sn: 0.8 to 2.0%, Sb: 0.04 to 0.15. %, Al: 0.4 to 0.7%, Bi: 0.5 to 2.5%, or Pb: 0.5 to 3.0%, B: 1 to 200 ppm, and the balance By containing Zn and inevitable impurities, a brass alloy having a composition balance excellent in erosion / corrosion resistance and molten metal flow may be used.
In this case, the macro crystal grains are refined, or the macro crystal grains are refined and the average area ratio of the γ phase is set to 2.8% or more, or (or in addition), The ISO maximum dezincification corrosion depth is ensured to 200 μm or less by surrounding the β phase with the phase.
Furthermore, you may make it refine | miniaturize a macro crystal grain, making this brass alloy for casting contain Fe: 0.04-0.4% and reducing B content.

  The brass alloy in this example is particularly suitable for molding by die casting, and when used for die casting, it can be easily formed even by a casting having a complicated shape as compared with sand casting. Inexpensive mass production is also possible. Furthermore, since it can prevent the generation of industrial waste such as foundry sand, it is environmentally friendly.

Next, the composition range of the casting brass alloy in the present embodiment and the reason thereof will be described.
Cu: 61.2 ≦ Cu <64.0 mass%
Cu is an essential element contained as a premise for obtaining an alloy having an α + β + γ structure or an α + γ structure. Although dezincing resistance can be improved by increasing the Cu content, in order to reduce the ISO maximum dezincing depth to 200 μm or less without performing heat treatment, the following contents of Sn and Sb, B and B On the premise of the refinement of macro crystal grains containing Fe, the Cu content is set to 61.2% or more as shown in Example 1 described later. Further, by setting the Cu content to 62.0% or more, the ISO maximum dezincing depth can be further reduced.
However, if the Cu content is increased, the solidified structure becomes dendrites, and the hot-water flow necessary for molding of the cast product is extremely reduced. Therefore, as shown in Examples 2 and 3 described later, the Cu content Is preferably set to a value lower than 64.0%, and more reliably 63.8% or less can suppress the formation of a dendrite structure and improve the hot water flowability.

Sn: 0.8-2.0 mass%
Sn is an essential element contained in order to ensure erosion / corrosion resistance.
When the content is 0.8% or more, the effect is manifested, and if it is premised on the refinement of macro crystal grains containing Fe together with B or B, the content is more sure when the content is 1.0% or more. Moreover, since cutting workability will fall by containing over 2.0%, the upper limit of Sn shall be 2.0%. In addition, as the Sn content increases, the tendency of the solidification form of the casting to become a Massy type is likely to cause poor hot water, shrinkage cavities, and casting cracks. Furthermore, from the viewpoint of securing elongation, as shown in Example 8 to be described later, the Sn content is preferably 1.7% or less. Furthermore, by setting the Sn content to 1.3 to 1.4%, excellent erosion / corrosion resistance even in relatively large castings such as a mixing faucet, as shown in Example 4 described later. Can be obtained.

Sb: 0.04 to 0.15 mass%
Sb is an essential element contained for improving dezincing resistance. As shown in Example 5 to be described later, the effect is manifested when the content is at least 0.04% or more (more certainly 0.06% or more), and particularly when the content is 0.06% or more, ISO maximum dezincification A corrosion depth of 200 μm or less is satisfied, and when the content is 0.08% or more, the effect becomes saturated. Moreover, since the tendency of embrittlement becomes strong when it exceeds 0.15%, the upper limit of Sb is set to 0.15%, and more preferably, the upper limit of Sb is set to 0.1% based on the saturation state.

Al: 0.4 to 0.7 mass%
Al is an indispensable element in the mold casting which is contained in order to improve the molten metal flowability of the alloy and produce a casting of good quality. Moreover, since this alloy contains Cu and Sn at a high concentration as described above in order to obtain corrosion resistance, Al is contained in an amount of 0.4% or more to ensure hot water flow. However, if Al is contained excessively, dezincing resistance is lowered, so 0.7% is made the upper limit.

B: 1 to 200 ppm
B is an essential element contained in order to refine the macro crystal grains and improve corrosion resistance such as dezincing resistance and erosion / corrosion resistance. Further, since it improves the castability such as improvement of hot water flow and suppression of casting cracking, it is an essential element in the alloy of the present invention containing Sn and Cu at a relatively high concentration in order to obtain corrosion resistance.
The effect of refinement of macro crystal grains due to the inclusion of B is obtained by the inclusion of 1 ppm as shown in Examples 7 to 9 described later. However, the excessive inclusion adversely affects the polishing properties due to the precipitation of the B compound. Therefore, the upper limit of the content is 200 ppm.
Among these, the refinement effect of the macro crystal grains in the casting produced by hermetic melting is obtained with a content of 1 to 30 ppm.
In addition, when using a molten metal coating material by melting in the atmosphere, it is necessary to contain about 30 to 100 ppm in order to obtain refinement of macro crystal grains. Can reduce the B content, and the inclusion of 5 to 30 ppm makes it possible to obtain finer macro crystal grains.
When melt | dissolving by the perfect open | release to the atmosphere which does not use a molten metal coating | covering material, refinement | miniaturization of a macrocrystal grain is obtained by containing 100-200 ppm.
As the method for adding B, it is most effective to add it in the form of a halogen compound such as potassium tetrafluoroborate, or a halogen compound not containing B and Cu-B. This is because oxygen and hydrogen gas present in the molten metal are removed by the halogen compound, and the molten metal is coated to suppress the incapability due to the oxidation of B.

Fe: 0.04 to 0.40 mass%
Fe is an optional element that is contained together with B in order to refine macrocrystal grains and improve corrosion resistance such as dezincing resistance and erosion / corrosion resistance. Although refinement of macro crystal grains due to the inclusion of only Fe does not extend to refinement due to the inclusion of B, Fe may be an element that assists refinement of macro crystal grains due to the inclusion of B according to examples described later. It has been confirmed that the inclusion of Fe makes it possible to refine the macro crystal grains while reducing the expensive B content. Therefore, the inclusion of Fe is a very effective means of refining macro crystal grains in actual operations because it refines macro crystal grains and improves dezincing resistance while suppressing material costs.
In order to assist the refinement of macro crystal grains due to the inclusion of Fe by the inclusion of Fe, as shown in Example 9 to be described later, it is necessary to contain at least 0.04% or more, and 0.07%. By containing the above Fe, dezincing resistance can be improved reliably.
On the other hand, if Fe is contained excessively, the generation of hard spots is promoted, and there is a concern that the machinability and the abrasiveness are lowered. Therefore, the upper limit is made 0.40%. More preferably, the upper limit is 0.22%.

Pb: 0.5 to 3.0 mass%
Pb is an arbitrary element that improves machinability. Depending on the required machinability, it is contained in an amount of 0.5% or more. However, if it exceeds 3.0%, the cast cracking resistance, tensile strength and elongation are lowered, so the content is made 3.0% or less. In a brass alloy containing 0.5 to 2.5% of Bi to be described later, Pb is an element that lowers the impact value at 100 ° C. or higher. When the usage environment is 100 ° C. or higher, it is necessary that the allowable amount of Pb relative to Bi is 0.012. Thus, by defining the allowable amount of Pb with respect to Bi, it is possible to prevent a decrease in impact value at 100 ° C. or higher, and to enable the use of reusable materials such as chips, thereby reducing the environmental load and cost. Can be reduced.

Bi: 0.5 to 2.5 mass%
Bi is an optional element that improves machinability. When the content is at least 0.5% or more, and when free machining is most important, the content is 2.5% or less. If it exceeds 2.0%, the cast cracking resistance, tensile strength and elongation decrease, so the preferred range is made 2.0% or less. In the brass alloy containing 0.5 to 3.0% of Pb described above, Bi is an element that lowers the impact value at 100 ° C. or higher. When the usage environment is 100 ° C. or higher, the Bi content relative to Pb needs to be 0.06 or less by weight. Thus, by defining the allowable value of Bi with respect to Pb, it is possible to prevent a drop in impact value at 100 ° C. or higher, and to enable the use of reusable materials such as chips, thereby reducing the environmental burden and cost. Can be reduced.

Ni: 0.2-1.0 mass%
Ni is an optional element contained in the case where the tensile strength is improved and the dezincing resistance is improved, and the effect becomes effective at 0.2% or more. On the other hand, if the Ni content exceeds 1.0%, an intermetallic compound is generated, which becomes a hard spot, which deteriorates the machinability / polishing property.

Se: 0-0.35 mass%
Se is an optional element added as necessary. Se exists in the alloy as SeZn, and is effective for a finer, chip breaker, Bi segregation suppression, microporosity dispersion, and the like. An effect is seen from 0.05% or more, and it improves as the content increases. In particular, the optimum value is 0.2% due to the suppression of segregation of Bi and the dispersion effect of microporosity, but excessive addition causes the mechanical properties to deteriorate, so 0.35% is made the upper limit.

P: 0.01 ≦ P <0.06 mass%
P is an optional component that can improve dezincing resistance, but is also a component that tends to cause casting cracks. While this P is suppressed to the impurity level, Sn and Sb can be contained to obtain a dezincing resistance effect. In addition, when P is positively contained, a tendency to suppress casting cracks can be obtained by suppressing it to less than 0.06 mass%. Therefore, as a component range corresponding to mold casting, 0.01 ≦ P <0.06 mass%.

Inevitable impurities: Mn, Si, Zr, Ti, Mg, As, Cr, P
Mn hardens the structure and reduces machinability. In addition, the usage is limited when reused. Therefore, Mn: 0.03 mass% or less.
Si is a component contained in a brass material that requires hot workability, but since it is also a component that hardens and becomes brittle, the casting brass alloy according to the present invention treats it as an impurity level. The component value is 0.1 mass% or less.
Zr may be added as a crystal refining element, but if the content is increased, the material strength is lowered.
Ti is a component that improves the matrix strength and increases the tensile strength, but if the content is increased, the oxide may be involved, so the content is made 0.2 mass% or less.
Mg may be added as an element that suppresses the generation of Zn oxide, but if the content is increased, the corrosion resistance and tensile strength may be reduced, so 0.1 mass% or less.
Since As is a harmful substance, it is set to 0.05 mass% or less.
Since Cr is a component that makes the alloy brittle, it is set to 0.005 mass% or less.
Note that P as an impurity level is less than 0.01 mass%.

  The above-described brass alloy for casting is manufactured as an intermediate product such as an ingot or a continuous casting product, or directly cast and processed and manufactured as a wetted part. Among these, as the wetted parts, for example, valve parts for drinking water, valve parts such as stems, valve seats, discs, piping equipment such as faucets and joints, equipment for water supply / drainage pipes, strainers for wetted liquids, pumps, motors Appliances, faucet fittings, hot water-related equipment such as hot water supply equipment, parts and members such as water supply lines, intermediate products such as the above-mentioned final products, assemblies, coils, and hollow bars.

  Next, in determining the desirable composition balance of the brass alloy for casting according to the present invention, various evaluation tests were conducted in each example, and the results were considered. Each example will be described below.

  A brass alloy having a different Cu content was used as a test material, and the ISO dezincing resistance of each test material was evaluated. The specimen is manufactured by the specimen manufacturing method shown in FIG. In the present Example 1, it melted | dissolved using the molten metal coating | covering material in the state of open air shown to the method B among these. This specimen was a casting formed by a φ13 × 50 mm or φ35 × 80 mm mold, and was formed by a φ13 mold in FIG. 2A or a φ35 mold in FIG. 2B.

  The corrosion test for dezincing was performed according to the dezincification corrosion test method for brass specified in ISO 6509-1981. The test method was that a 1% cupric chloride aqueous solution was maintained at 75 ° C., and a sample (test material) finished to # 1500 with emery paper was immersed in a test tank for 24 hours, and then this sample was taken out and cross-sectioned. The corrosion depth and morphology of the steel were measured by microscopic observation. By this microscopic measurement, a sample having a maximum corrosion depth of 200 μm or less was examined.

Table 1 shows the results of evaluating the ISO dezincing resistance by changing the Cu content. Table 1 shows Pb-containing alloy data.
Specimen Nos. 1 to 7 are made by refining macro crystal grains by containing B, and test specimens Nos. 8 to 14 are made by refining macro crystal grains by Fe and B. In addition, all these experimental results evaluated the test material which refined | miniaturized the macrocrystal grain by B or B and Fe, and have shown the average value of the number N of test materials N = 2.

The results of the maximum dezincing depth in Table 1 are plotted on the graph in FIG. In FIG. 3 (a), the content value of B is made close to 40 ppm, and in FIG. 3 (b), the content value of B is made 10 ppm and the content value of Fe is made close to 0.2%. Is.
As shown in Table 1 and the relationship between the amount of Cu and the ISO maximum dezincification depth shown in FIG. 3, in order to make the ISO maximum dezincification depth 200 μm or less, the optimum component range (composition balance) in other elements And the Cu content is 61.2% or more on the premise of making the crystal grains fine with B or Fe. In the case of φ13 castings, the test material No. 1-4, no. As shown to 11-14, it becomes possible to reduce ISO maximum dezincing depth by making content of Cu 62.0% or more.

  Table 2 shows Bi-based alloy data containing Bi, and evaluates test materials in which macro crystal grains are refined with Fe and B. From this, it was confirmed that the content of Cu is at least 61.2% and the maximum ISO dezincification corrosion depth is 200 μm or less. In addition, specimen No. As shown in FIG. 19, it was confirmed that even when Ni = 0, the ISO maximum dezincification corrosion depth of 200 μm or less can be satisfied.

This example shows the basis for the upper limit value of Cu. In addition, this example is Pb containing alloy data. Using the specimen, the relationship between the Cu content and the rate of defective hot water was investigated. The test material was produced by hermetic dissolution shown in Method C in FIG. This test material is a water-stopper made of die casting having a nominal diameter of 1/2 inch shown in FIG.
Table 3 shows the relationship between the Cu content and the rate of defective hot water.

  In Table 3, the test material No. with a Cu content of 64.2% was used. No. 21 has an extremely high hot water defect rate of 87.5%. This is because the flowability of the hot water is lowered by the solidified structure becoming dendrites. On the other hand, the test material No. with a Cu content of 63.4% was obtained. No. 24 had a low hot water circulation defective rate of 11.7%, and it was confirmed that the hot water flowability was good.

  In addition, specimen No. with Sn increased to 0.8%. 23, the hot water failure rate is as high as 65.8%. This is because when the solidification form becomes Massy, the hot water flowability is lowered. It is important to keep Sn low to improve the hot water flowability. However, as will be described later, in order to ensure erosion / corrosion resistance, the content of Sn of 0.8% or more is essential. It is necessary to contain B like 24 and to improve hot-water flow property. Thereafter, it was confirmed that all the levels containing B have good hot water flowability.

  In this example, the relationship between the Cu content of the Bi-containing material and the hot water flowability was investigated by a hot water flow test. This test was conducted using a sand mold because it is easy to compare the hot water flow of the alloys. 14 (a) and 14 (b) show a test method for a hot water flow test by a spiral flow test method (see, for example, a dictionary of technical terms for metal materials, published by Nikkan Kogyo Shimbun). In addition, although the casting in this example was performed according to the method B of FIG. 1, since a temperature fall is unavoidable when pouring hot water from a melting furnace to a ladle and pouring from a ladle to a tundish, FIG. The melting temperature was 1070 ° C. with respect to the melting temperature of 1000 ° C. All the test materials were evaluated by refining macro crystal grains with B and Fe. Table 4 shows the chemical component values of the test materials and the hot water flow test results, and FIG. 15 shows the relationship between the Cu content and the hot water flow length.

In this result, the sample No. with a Cu content of 63.8% was obtained. No. 32 has a good hot-water flow property, and furthermore, the specimen No. 31 was confirmed to have excellent hot water flowability.
Here, the hot water flow length of the alloy of the present invention needs to be within an allowable range of 20% of JIS H5120 CAC203, which is a general brass casting, in consideration of manufacturing conditions during mass production. The hot water flow length of CAC203 in the above test is about 500 mm, and the acceptance standard of the alloy of the present invention is 400 mm. Therefore, based on the above test results, the upper limit value of the Cu content satisfying the hot water flow acceptance standard. Was set to a value lower than 64%, specifically 63.8% or less.
When Cu exceeding this upper limit is contained, for example, sample No. In 33 (Cu content is 64.3%), the hot water flow length is reduced to nearly 300 mm, and the castability of a thin cast such as a faucet increases.

Next, the erosion / corrosion resistance of the test materials having different Sn contents was evaluated. This example is Pb-containing alloy data.
In Table 5, the chemical composition values of the test material in which the Sn content was changed, the CAC203 which is a typical brass casting material for casting as a comparative material, and the CAC406 which is a bronze casting material having excellent corrosion resistance as a water supply member Is shown.

  Specimens No. 34 to 39 were prepared by hermetic dissolution shown in Method C of FIG. 1, and CAC203 and CAC406 were prepared in an experimental furnace shown in Method A of FIG. The test material is a sample taken from a φ35 × 80 mm mold casting in FIG. 2B and a sample cut out from the mold faucet main body shown in FIG. 5 and used. A test was conducted.

Here, the erosion / corrosion resistance is evaluated by a crevice jet corrosion test. In FIG. 6, the schematic explanatory drawing of the crevice jet corrosion test device is shown. As a test method, a test piece processed to have an exposed area of 64 mm ² (φ16 mm) with respect to a corrosive solution is mirror-polished and installed as shown in FIG. Next, a test solution (1% cupric chloride aqueous solution) is sprayed from the surface of the test piece at a rate of 0.4 liter / min from a spray nozzle having a height of 0.4 mm (nozzle diameter: 1.6 mm). After spraying the test solution for 5 hours, the mass is measured to determine the mass loss and the corrosion form is observed.

However, the mixed faucet (product cut-out sample) among the test materials used in this test is different from the test sample of FIG. That is, in the case of a water stop cock, since the thickness of the product is thin, it cannot be made into the same shape as the sample used for a normal crevice jet corrosion test. Therefore, as shown in FIG. 7, a thin sample of about 20 mm × 20 mm cut out from the product was filled with resin and machined so that it could be fixed to the sample holder of the apparatus was used as a test material. For this reason, the area of the exposed surface of the test material is different from the sample of FIG. 6, and the value of mass loss is a reference value.
The number of test materials was N = 1. The erosion / corrosion test results are shown in Table 6.

From Tables 5 and 6, the test material No. in which the macrocrystal grains are not refined is shown. Since B does not contain B, even when Sn is contained in an amount of 0.8%, the erosion / corrosion resistance of both the φ35 mold casting and the mixed water faucet is evaluated as x.
Next, test material No. 1 containing B and having refined macro crystal grains was used. No. 35 was evaluated as Δ for a φ35 mold casting, and erosion and corrosion resistance was improved.
Next, test material No. 1 containing 1% or more of Sn. 36 to 39 were all evaluated as ◎ in the φ35 die casting, and the erosion / corrosion resistance was further improved. In the case of the mixed faucet, the test material No. About 37-39, evaluation became (circle) or more and the erosion-corrosion resistance was improved.

In addition, the improvement of the erosion / corrosion resistance of the mixing faucet required more B than the φ35 mold casting because the mixing faucet is formed of a mold body and a sand core. This is probably because the metal structure tends to vary.
Based on the above, on the premise of optimization of other elements and refinement of macro crystal grains by the inclusion of B, the erosion / corrosion resistance contains at least Sn of 0.8% or more, and further adjusts the B content. Moreover, it becomes possible to improve reliably by containing Sn 1.0% or more.

  Next, regarding the influence of Sn and Sb on the dezincing resistance, the method A in FIG. 1 was melted by opening to the atmosphere + molten metal coating to prepare a φ13 mold casting, and the dezincing resistance of these test materials The properties were evaluated by the ISO dezincing resistance test method described above. This example is Bi-based alloy data containing Bi, and all the test materials were subjected to refinement of macro crystal grains with B and Fe. In addition, these test results have shown the average value of the number of test materials N = 2.

As shown in Table 7 and FIG. 16, the ISO maximum dezincification corrosion depth of the test material is as the Sb content increases in each data of Sn target values 0.9, 1.35, and 1.8. It was confirmed that when the content was at least 0.04% or more, the effect was exhibited, and at 0.06% or more, the ISO maximum dezincification corrosion depth of 200 μm or less was satisfied.
On the other hand, it was confirmed that Sn has a small influence on the dezincing resistance between 0.9% and 1.9%.

Next, improvement in dezincing resistance by refining macro crystal grains will be described.
First, this alloy is 61.2 ≦ Cu <64.0%, Sn: 0.8 to 2.0%, Sb: 0.04 to 0.15%, Al: 0.4 to 0.7%, In addition, at least one selected from Bi: 0.5 to 2.5% or Pb: 0.5 to 3.0%, which contributes to machinability, and the balance is Zn and inevitable impurities, no heat treatment Thus, the maximum ISO dezincing depth can be suppressed to about 400 μm or less, and superior dezincing resistance compared with CAC203 has been secured.

However, according to the evaluation standard of the dezincing resistance test method (ISO 6509-1981), 200 μm or less is regarded as A grade, and a material satisfying A grade is required practically. The required dezincing resistance cannot be satisfied stably.
Further, in order to ensure erosion / corrosion resistance, high concentration of Sn is contained, so that there is a concern that the flowability of molten metal is deteriorated and casting cracks and shrinkage cavities are likely to occur.

  As a result of further detailed studies, it was found that there is a correlation between refinement of macro crystal grains and dezincing resistance. Here, the macro crystal grain refers to a structure in which nuclei generated by heterogeneous nucleation grow in the solidification process, and α phase groups (β phase and γ phase existing in the gap of α phase are arranged in the same direction). A crystal grain having a unit). The microstructure seen in the extruded rod is visually recognized by observing the cut surface of the casting using a metal microscope, whereas the macrostructure according to the present invention is visually recognized using the naked eye or a magnifier of about 10 times. It is a structure that can be produced, and is a structure that is not found in the extruded rod.

In addition, as shown in FIG. 9, it is extremely rare that the maximum length of the macro crystal grain coincides with the maximum length of the crystal grain in the microstructure within one field of view.
The reason why the refinement of macro crystal grains is effective in improving the dezincing resistance is as follows.
Since the present invention relates to a cast alloy, it differs from the microstructure of the bar. In particular,
(1) The mold casting alloy is a casting and forms a solidified structure from the molten state, and therefore has a macro structure.
(2) Since there is no process such as hot working, it is not a granular structure due to recrystallization, but a needle-like structure.
(3) Since it is an assembly of complicated needle-like structures, it is impossible to specify the microcrystal grain size, grain shape, etc. in the bar.

Then, when the form of the cast structure was examined in detail, it was found that a needle-like structure having a certain directivity tends to develop in one macro crystal grain as shown in FIGS. In addition, when the state of the above cast product after the dezincing resistance test was investigated, the dezincing corrosion tends to proceed in the length direction of the needle-like structure, and is parallel to the corrosion depth direction of the dezincing resistance test. It was also found that when the acicular structure grows in the direction, the rate of progress of corrosion is fast.
Furthermore, it has also been found that the corrosion progressing speed in the acicular structure having a certain directionality changes by colliding with acicular structures (different macro crystal grains) grown in the other direction.

  Therefore, it has been elucidated that the progress of corrosion can be suppressed and the dezincing resistance can be improved by refining the macro crystal grains. In this case, the macro crystal grain needs to be refined in at least the wetted part of the wetted part. For example, in the case of a valve, the wetted part is a processed surface such as a valve seat or an inner peripheral surface of a pipe connection part or a cast surface in addition to the surface of the valve body in the flow path of the valve body, the valve body, etc. Say. In this way, if the macro crystal grains in the surface structure such as the valve seat, which has the fastest flow rate and is easily eroded at least inside the valve of the wetted parts, are refined, the macro crystal grains are refined in the entire wetted parts. It can be handled as a thing.

  Further, the refinement of macro crystal grains is effective for improving castability. Usually, an alloy containing Sn exceeding 0.2% frequently causes poor hot water casting and casting cracks, but these defects can be suppressed by making the macro crystal grains finer.

Here, when showing the criteria for the refinement of macro crystal grains in the present invention,
(1) The test material is corroded for about 1 second with a corrosive solution consisting of hydrogen peroxide water + ammonia water, and when the corroded surface is observed with the naked eye, macrocrystal grains cannot be confirmed, and the following judgment is made. You may use a standard together.
(2) The specimen is corroded for about 1 second with a corrosive solution consisting of hydrogen peroxide water + ammonia water, and when the microstructure is observed with a metal microscope, the standard is that the crystals are granular.

  A specific example of this criterion is shown in FIG. 12. In FIG. 12, the macrostructure and schematic diagram of an alloy in which macrocrystal grains are refined in the present invention and an alloy in which macrocrystal grains are not refined as a comparative example, and the microstructure are shown. Indicates. Each sample in the drawing is a specimen No. in Table 10 described later. 80, no. It was composed of 82 compositions, and all were manufactured using a φ13 mold.

  According to this, in sample A in which the macro crystal grains are miniaturized, the macro crystal grains are so fine that the macro crystal grains cannot be confirmed with the naked eye, whereas in sample B in which the macro crystal grains are not miniaturized, the macro crystal grains are macroscopically visible. I can confirm. In this sample B, columnar crystals grow from the mold, and coarse equiaxed crystals can be confirmed near the center. The microstructure is an enlargement of the vicinity of the center of each sample shown in the macro structure. In the sample A in which the macro crystal grains are refined, the crystals are granular, whereas in the sample B in which the macro crystal grains are not refined, the crystals are acicular.

  Incidentally, in the “Presence / absence of refinement of macro crystal grains” column in each example in the specification, a test product in which macro crystal grains are miniaturized, that is, a sample belonging to sample A is displayed as “◯”. Samples whose macrocrystal grains are not miniaturized, that is, samples belonging to the sample B are indicated as “x”.

  Next, Table 8 shows the relationship between the refinement of macro crystal grains and the dezincing resistance with respect to the B content. Among the test materials, Nos. 52 to 59 are φ13 mold castings that were prepared after being released into the atmosphere and melted using the molten metal coating material shown in Method B of FIG. ˜62 are φ13 mold castings produced by melting in the atmosphere without using the melt coating material shown in the method A of FIG. The dezincing resistance of these test materials was measured by the ISO dezincing resistance test method described above. In addition, these experimental results have shown the average value of the number of test materials N = 2. Specimen No. A graph of the test results of 52 to 59 is shown in FIG. A graph of the test results of 60 to 64 is shown in FIG.

  From the results shown in the figure, it was confirmed that the refinement of macro crystal grains improved the dezincing resistance and satisfied the ISO maximum dezincification corrosion depth of 200 μm or less. Further, the macrocrystal grains are refined at 36 ppm or more when the melt coating material is used, whereas the macrocrystal grains are not refined at 81 ppm when the melt coating material is not used. First, macrocrystal grains were refined with a content of 146 ppm. As described above, the use of the melt coating material in the open air furnace makes it possible to achieve miniaturization with a small B content. Moreover, it was confirmed that refinement | miniaturization of a macrocrystal grain was obtained by the same B content with the material containing Pb or the material containing Bi.

Further, Table 9 shows the results of the relationship between the refinement of macro crystal grains and the dezincing resistance with respect to the B content in a 1.8 t large closed furnace. The specimen is a φ13 die casting produced by melting and sealing as shown in Method C of FIG. The dezincing resistance of these test materials was measured by the ISO dezincing resistance test method described above. In addition, these experimental results have shown the average value of the number of test materials N = 2.
Table 9 also shows the results of a tensile test performed on a JIS Z2201 No. 4 tensile test piece collected from a JIS H5120 B specimen (die) and machined using an Amsler universal testing machine.

From the results of Table 9, when Fe is contained, at least the B content necessary for refining the macro crystal grains is 1 ppm or more, and more certainly 3 ppm or more is necessary. It was also confirmed that the dezincing resistance was improved with the refinement of macro crystal grains.
The tensile test results confirm that both the tensile strength and elongation are improved by refining the macro crystal grains. These are the JIS standard values of the mechanical properties of CAC203, the tensile strength is 245 MPa or more, and the elongation is 20 % Was fully satisfied. However, No. containing 1.7% of Sn. In No. 74, the tensile strength is improved due to the high content of Sn, but the elongation is reduced. When the standard value of the CAC203 elongation of 20% or more is used as a reference value, Sn 1.7% or less is sufficient to ensure sufficient elongation. It was confirmed that it was desirable.

  Next, in a small 15 kg high-frequency experimental furnace, in the casting method shown in Method B of FIG. 1 using the air melting and molten metal coating material, the test material produced by introducing B into the molten metal containing Fe was used as a target. Table 10 shows the results of investigations on the relationship between the content of B and Fe and the refinement of macro crystal grains. Here, the specimen is a mold casting of φ13. The dezincing resistance of these test materials was measured by the ISO dezincing resistance test method described above. This example is Pb-containing alloy data. In addition, these experimental results have shown the average value of the number of test materials N = 2.

Sample No. B with B less than 10 ppm. 80-86, the macrocrystal grains were refined because of the test material No. containing 0.07% Fe. Only 82. Even if the Fe content is increased while the B content is less than 10 ppm, Fe 0.03% of the test material No. No. 80 and Fe 0.28% test material No. As shown in 83, the macro crystal grains were not refined. In addition, test material No. 93 was not refined even though B was 22 ppm.
On the other hand, the test material No. containing 11 to 43 ppm of B and 0.04 to 0.22% of Fe. In 87-92, all were refined.

  From the above, the lower limit of the Fe content that assists the refining action of the macro crystal grains of B and secures the predetermined dezincing resistance is 0.04%, and the higher content is more than 0.07%. can get. At least the effect of Fe lasts up to a content of 0.22%, but after 0.40%, the effect decreases. Therefore, when melt coating material is used for melting in the atmosphere, it is necessary to contain about 40 ppm of B when Fe is not contained, but when Fe is contained, it can be reduced to at least 5 ppm. confirmed.

Table 11 shows the amounts of B and Fe required for other melting methods and macrocrystal grain refinement in Pb-containing materials.
Specimen No. From the results of 94 and 95, in the case of melting in a completely open atmosphere that does not use a molten metal coating material, the B content (no Fe content) necessary for refining macro crystal grains is 100 to 200 ppm. It was confirmed that it was in an appropriate range.
Specimen No. From the results of 96 and 97, when the molten metal coating material is used for melting in the atmosphere, the content of B necessary for refining the macro crystal grains (no Fe content) is within a proper range of 30 to 100 ppm. It was confirmed.
Specimen No. From the results of 98 and 99, in the case of hermetic dissolution, it was confirmed that the content of B necessary for refining the macro crystal grains is within a proper range of 1 to 3 ppm.

Table 12 shows the dissolution method in the Bi-containing material and the amounts of B and Fe necessary for refining the macro crystal grains. Even in the Bi-containing alloy, it was confirmed that the macro crystal grains were not refined when Fe was contained in excess of 0.4%.
Specimen No. From the results of 100 and 101, in the case of melting in a completely open atmosphere that does not use a molten metal coating material, the B content (no Fe content) necessary for refining the macro crystal grains is 100 to 200 ppm. It was confirmed that it was in an appropriate range.
Specimen No. From the results of 102 and 103, when using the molten metal coating material by melting in the atmosphere, the content of B necessary for refining the macro crystal grains (no Fe content) is within a proper range of 30 to 100 ppm. It was confirmed.
Specimen No. From the results of 104 and 105, it is confirmed that the content of B necessary for refining the macro crystal grains is in an appropriate range of 5 to 30 ppm when using the molten metal coating material by melting in the atmosphere with Fe. It was.
Specimen No. From the results of 106 to 110, when using the molten metal coating material by melting in the atmosphere, the content of Fe necessary for refining the macro crystal grains is in the proper range of 0.04 to 0.4%. is there.

Next, precipitation of γ phase and improvement of dezincing resistance by refining macro crystal grains will be described.
As an example in which the dezincing resistance is improved by refining the macro crystal grains, the test material Nos. In the test material shown in 116, although the Cu content is low and the composition is unfavorable for securing the dezincing resistance, the macro crystal grains are finely contained by containing 14 ppm of B and 0.16% of Fe. And a dezincification corrosion depth of 200 μm or less is obtained.

However, the specimen No. having the same composition. As shown in 118, even when the macro crystal grains are refined, the ISO maximum dezincification depth may exceed 200 μm. 116, φ35, specimen No. 118 is different from φ13, but the effect of the type of mold and the size of the casting on the dezincing resistance was clarified by analyzing the microstructure.
Each sample material is a casting produced by a casting method shown in Method B of FIG. The dezincing resistance of these test materials was measured by the ISO dezincing resistance test method described above. The number of test materials is N = 1.

FIG. 13A and FIG. 13B show enlarged microstructure photographs before and after crystal grain refinement in a sample produced in a sand mold, with the dezincification corrosion portion enlarged.
From the results shown in the figure, it can be seen that the crystal structure becomes granular due to the refinement of the macro crystal grains, resulting in a structure in which the β phase is separated, and the precipitation amount of the γ phase is clearly increased. Dezincification corrosion preferentially proceeds in the β phase over the γ phase in this alloy system. Although the γ phase is also corroded, it tends to be less corroded than the β phase, and the γ phase surrounds the β phase, which is considered to delay the progress of corrosion.
The surrounding state of the β phase by the γ phase is at least 61.2 ≦ Cu <64.0%, Sn: 0.8 to 2.0%, Sb: 0.04 to 0.15%, Al: 0.3. It can be obtained by a composition comprising 4 to 0.7%, Pb: 0.5 to 3.0%, B: 1 to 200 ppm, and the balance Zn and inevitable impurities.

Next, in order to quantitatively grasp the relationship between the γ phase and the dezincification corrosion resistance, the area ratios of the α phase, the β phase, and the γ phase were measured. Show.
The area ratios of the α, β, and γ phases were measured by a point calculation method using 26 × 26 grid lines, and the number of measurement fields was five. In the present invention, a sample cast in a mold uses a x1500 microstructure, and a sample cast in a sand mold uses a x1000 microstructure. The difference in measurement magnification is due to the fact that the size of the microstructure differs depending on the presence or absence of miniaturization or the type of mold, and measurement at a magnification suitable for the size of the microstructure is necessary.

From the results shown in the table, it is possible to ensure the ISO maximum dezincification depth of 200 μm or less without heat treatment by ensuring at least 2.8% or more of the γ phase ratio by refining the grains assuming the inclusion of Sn. It became.
Further, the brass alloy for casting according to the present invention has a test material No. As shown at 114, it was also applied to a casting made of a sand mold, and it was confirmed that more γ phase was precipitated than a mold casting. When attention was paid to the size of the casting, it was confirmed that the γ phase area ratio of the φ35 casting was larger than the γ phase area ratio of the φ13 casting.
The alloy of the present invention improves the dezincing resistance to a level satisfying the ISO maximum dezincification corrosion depth of 200 μm or more without performing a heat treatment. You may add well-known alpha heat processing as needed.

Claims (9)

  By mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8-2.0%, Sb: 0.06-0.15%, Al: 0.4-0.7%, Pb: 0.5 to 3.0%, B: 1 to 200 ppm, an α + β + γ structure or an α + γ structure composed of the balance Zn and inevitable impurities, which refines macrocrystal grains and has an average area ratio of γ phase of 2. A casting alloy characterized by ensuring the maximum ISO dezincification corrosion depth to 200 μm or less by setting it to 8% or more.   By mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8-2.0%, Sb: 0.06-0.15%, Al: 0.4-0.7%, Bi: 0.5 to 2.5%, B: 1 to 200 ppm, an α + β + γ structure or an α + γ structure composed of the balance Zn and inevitable impurities, refines macrocrystal grains, and has an average area ratio of γ phase of 2. A casting alloy characterized by ensuring the maximum ISO dezincification corrosion depth to 200 μm or less by setting it to 8% or more.   By mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8-2.0%, Sb: 0.06-0.15%, Al: 0.4-0.7%, Pb: 0.5 to 3.0%, B: 1 to 200 ppm, α + β + γ structure or α + γ structure composed of the balance Zn and inevitable impurities, refined macro crystal grains, and surrounded by β phase by γ phase A cast alloy characterized by ensuring a maximum dezincification corrosion depth of 200 μm or less.   By mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8-2.0%, Sb: 0.06-0.15%, Al: 0.4-0.7%, Bi: 0.5 to 2.5%, B: 1 to 200 ppm, α + β + γ structure or α + γ structure composed of the balance Zn and inevitable impurities, refines macro crystal grains, and surrounds the β phase with the γ phase to form ISO A cast alloy characterized by ensuring a maximum dezincification corrosion depth of 200 μm or less.   The copper alloy according to any one of claims 1 to 4, wherein, by mass ratio, Fe: 0.04 to 0.4% is contained to reduce the B content to 1 to 30 ppm. alloy.   The cast alloy according to any one of claims 1 to 5, wherein Ni: 0.2 to 1.0% is contained in a mass ratio. A wetted part machined and formed using the cast alloy according to any one of claims 1 to 6. Casting alloy according to any one of claims 1 to 6 were prepared by a die casting. Wetted parts made of Casting alloy according to claim 8.

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