JP4871380B2 - Copper-base alloy for casting - Google Patents

Description

  The present invention relates to a copper base alloy for casting.

  General casting brass, such as YBsC3 (CAC203), tin (Sn) is 1.0 mass% or less, lead (Pb) is 0.5 to 3.0 mass%, aluminum (Al) is 0.5 mass. % Or less, iron (Fe) is 0.8 mass% or less, copper (Cu) is 58.0 to 64.0 mass%, and zinc (Zn) is the balance. YBsC3 is used in products such as faucet fittings and water pipes such as water pipes from the viewpoints of castability and machinability.

  However, YBsC3 has a problem that dezincification corrosion occurs. Dezincification corrosion is one type of decomponent corrosion that causes zinc in brass components to escape. According to the test results of the inventors, YBsC3 showed a dezincification depth of 198 μm in the JBMAT-303 test. In addition, erosion is corrosion in which material is shaved by the flow of water. For example, if a product with a mechanism that stops water at the seat part, such as a single water tap or a stop cock, is produced using general brass, the sheet part will be eroded, leading to poor water stoppage. .

  Therefore, higher corrosion resistance is currently required for products made of general brass for casting. For this reason, the copper base alloy for casting which considered the corrosion resistance of patent document 1 is proposed.

  The copper-based alloy for casting disclosed in Patent Document 1 is 0.05 to 0.2% by mass of tin, 0.5 to 3.0% by mass of lead, 0.1 to 0.5% by mass of aluminum, antimony ( Any one or more of Sb), arsenic (As) or phosphorus (P) is 0.05 to 0.3% by mass, zinc is 33.0 to 37.0% by mass, and copper is the balance.

  This casting copper base alloy has higher corrosion resistance than general casting brass. For example, according to the test results of the inventors, the copper base alloy for casting of Patent Document 1 showed a dezincification depth of about 30 to 50 μm in the JBMAT-303 test.

Japanese Patent No. 3461081

  However, according to the test results of the inventors, even a copper base alloy for casting considering the above corrosion resistance is not sufficient in dezincing resistance and castability. The same applies to other commercially available copper-based alloys for casting. For this reason, the copper base alloy for casting which can exhibit more superior dezincing resistance and castability is desired.

  This invention is made | formed in view of the said conventional situation, Comprising: It is set as the problem which should be solved to provide the copper base alloy for casting which can exhibit more superior dezincing resistance and castability.

  The inventors have intensively studied to solve the above problems, and are a copper-based alloy for casting containing copper, zinc, tin and antimony as a main component, and by optimizing the amount of tin and antimony, It has been found that dezincing resistance and castability are improved. Thus, the inventors have completed the present invention.

That is, the copper-based alloy for casting of the present invention is a copper-based alloy for casting containing copper, the main component of which is zinc, tin and antimony,
The amount of tin and the amount of antimony are 0.015 mass% for antimony and 0.013 to 0.203 mass% for tin and 0.203 for tin in a coordinate system in which the tin amount and the antimony amount are expressed in mass%. And a straight line of 0.015 to 0.047% by mass of antimony, 0.047% by mass of antimony and 0.047 to 0.203% by mass of tin, 0.047% by mass of tin and antimony Is 0.047 to 0.141% by mass, antimony is 0.141% by mass and tin is 0.013 to 0.047% by mass, tin is 0.013% by mass and antimony is 0.015%. within the range surrounded by the straight line ～0.141 wt% (inclusive.) der is,
Lead is 2.0 ± 0.2 mass%, iron is 0.11 ± 0.05 mass%, nickel is 0.5-1.0 mass%, aluminum is 0.4 ± 0.1 mass%, zinc is 36.0 ± 0.5 wt%, the balance being copper der Rukoto (claim 1).

  As shown in FIG. 1, this range is surrounded by ABCDEF in the coordinate system in which the tin amount and the antimony amount are expressed in mass%. According to the test results of the inventors, a copper-based alloy for casting containing copper, zinc and tin and antimony, and a copper-based alloy for casting having an amount of tin and antimony within this range is JBMAT. In the −303 test, the average dezincing depth was 15 μm or less, and the dezincing resistance was improved as compared with the conventional copper base alloy for casting considering corrosion resistance. It is speculated that the interaction was effectively expressed by optimizing the contents of tin and antimony. For example, even if tin is 0.013 to 0.203 mass%, the copper-based alloy for casting having 0.047 to 0.141 mass% of antimony is not sufficiently dezincing resistant. For example, a copper-based alloy for casting with 0.081% by mass of tin and 0.084% by mass of antimony has an average dezincing depth of 32 μm and is not sufficiently dezincing resistant.

  Moreover, the copper base alloy for casting of the present invention has a solidification latent heat exceeding 72 J / g, and the molten metal flowability is good. The latent heat of solidification is the total amount of heat energy required when the phase of a substance changes. The larger the value, the more difficult it is to change from a liquid state to a solid state, so the flow of hot water is considered to improve. It has been. Also in this respect, it is presumed that the interaction was effectively expressed by optimizing the contents of tin and antimony. For example, even if tin is 0.013 to 0.203 mass%, the casting copper-base alloy having 0.047 to 0.141 mass% of antimony does not have sufficient molten metal flowability. For example, a casting copper base alloy having 0.081% by mass of tin and 0.084% by mass of antimony has a solidification latent heat of 72 J / g, and the molten metal flowability is not sufficient.

  Therefore, according to the copper base alloy for casting of the present invention, it is possible to exhibit better dezincing resistance and castability.

  According to the test results of the inventors, the copper-based alloy for casting according to the present invention has 0.013 to 0.047% by mass of tin and 0.015 to 0.141% by mass of antimony. Preferred (claim 2). As shown in FIG. 1, this range is surrounded by AGEF in a coordinate system in which the tin amount and the antimony amount are expressed in mass%. This copper base alloy for casting has an average dezincing depth of 13 μm or less, and the dezincing resistance is further improved. Moreover, this copper-based alloy for casting has a solidification latent heat of 78 J / g or more, and the molten metal flowability is better.

Further, according to the test results of the inventors, the copper-based alloy for casting of the present invention has 0.013 to 0.203 mass% tin and 0.015 to 0.047 mass% antimony. it is also not preferable. As shown in FIG. 1, this range is surrounded by ABCH in a coordinate system in which the tin amount and the antimony amount are expressed in mass%. This copper-based alloy for casting makes the amount of tin that is easily contained as an impurity in a wide range, while narrowing the amount of antimony that is hardly contained as an impurity. For this reason, in this case, it becomes possible to manufacture the copper base alloy for casting of the present invention under simple management conditions.

In particular, according to the test results of the inventors, the copper-based alloy for casting of the present invention has 0.013 to 0.047% by mass of tin and 0.015 to 0.047% by mass of antimony. it is not preferable. As shown in FIG. 1, this range is surrounded by AGDH in a coordinate system in which the tin amount and the antimony amount are expressed in mass%. This copper-based alloy for casting has an average dezincing depth of 9 μm or less, and the dezincing resistance is further improved.

According to the inventors the test results, casting copper based alloys of the present invention, it is not preferable zinc is a 35.0 to 37.0 wt%. The inventors confirmed the above effects in these copper-based alloys for casting.

Further, according to the test results of the inventors, casting copper based alloys of the present invention, it has preferably may comprise lead, iron, nickel and aluminum. The copper-based alloy for casting of the present invention has a lead content of 2.0 ± 0.2% by mass, iron of 0.11 ± 0.05% by mass, nickel of 0.5-1.0% by mass, and aluminum of 0.1%. 4 ± 0.1 wt%, zinc 36.0 ± 0.5 wt%, it is not more preferable balance being copper. The inventors confirmed the above effects in these copper-based alloys for casting. Lead improves the workability of the casting copper base alloy, iron refines the crystals of the casting copper base alloy, nickel improves the corrosion resistance of the casting copper base alloy, and aluminum improves the hot water flow. In addition, the copper base alloy for casting according to the present invention may contain other inevitable impurities.

It is the coordinate system which represented the amount of tin and the amount of antimony in the mass%. It is a graph which shows the relationship between tin amount and antimony amount, and an average dezincification depth. It is a graph which expands and shows the relationship between the amount of tin and antimony, and average dezincification depth. It is a graph which shows the relationship between the amount of tin and antimony, and solidification latent heat. It is a graph which expands and shows the relationship between the amount of tin and antimony, and solidification latent heat.

  Hereinafter, the present invention will be described based on tests.

  In order to investigate the effect of the addition of tin and antimony, a copper base alloy for casting added with tin, antimony and the like with the composition shown in Table 1 was prepared, and samples 1 to 30 were cast using these copper base alloys for casting. . About each sample, the below-mentioned dezincing resistance test and solidification latent heat evaluation were performed.

(Dezincing resistance test)
JBMA T-303 test: Carbonate buffer solution (5 × 10 ⁻³ M NaHCO ₃ ) containing chloride (0.5 NaCl) was used as a test solution (60 ° C.), and CO ₂ + O ₂ + N ₂ (10:20). : 70) In an environment saturated with a mixed gas, an anode current of 1.0 mA / cm ² was passed through each lead (area 100 to 200 mm ² ) embedded in the resin through a lead wire for 24 hours, and the cross section was observed with a microscope. Observing, the average depth (μm) of the dezincification layer was measured.

(Coagulation latent heat evaluation)
DSC analysis: Thermal analysis was performed for each sample. Measurement conditions are a temperature rising rate of 20 ° C./min (700 ° C.) → 10 ° C./min (1030 ° C.) → 10 ° C./min (700 ° C.). Atmosphere, a N _2, the standard samples and used cell was Al ₂ O _3.

  Table 1 shows the composition, average dezincing depth (μm), and latent heat of solidification (J / g) of each sample. 2 and 3 show the relationship between the tin amount and antimony amount and the average dezincing depth, and FIGS. 4 and 5 show the relationship between the tin amount and antimony amount and the latent heat of solidification.

  As shown in Table 1, FIG. 2 and FIG. 3, the samples 4 to 8, 11 to 17, 20, 21, 23, 26, 27, 29 in which the tin amount and the antimony amount are surrounded by ABCDEF in FIG. 30 has an average dezincification depth of 15 μm or less. On the other hand, the sample 24, which is a conventional copper base alloy for casting considering the corrosion resistance, has an average dezincing depth of 32 μm. For this reason, samples 4-8, 11-17, 20, 21, 23, 26, 27, 29, 30 have improved dezincing resistance compared to sample 24. Samples 4-8, 11-17, 20, 21, 23, 26, 27, 29, and 30 are samples 3 in which tin is less than the range surrounded by ABCDEF in FIG. 1, and antimony is ABCDEF in FIG. The dezincing resistance is improved as compared with the samples 9, 10, 18, 19, 25, 28 which are smaller than the enclosed range. For this reason, in the copper base alloy for casting, it can be seen that tin and antimony are not too much and not too little, and an excellent effect can be exhibited by optimization.

  In addition, samples 4 to 7 and 11 to 17 in which the tin amount and the antimony amount are surrounded by AGEF in FIG. 1 have an average dezincification depth of 13 μm or less, and the dezincing resistance is further improved.

  In particular, samples 4, 5, 7, 13, and 14 in which the tin amount and antimony amount are surrounded by AGDH in FIG. 1 have an average dezincification depth of 9 μm or less, and the dezincing resistance is further improved. ing.

  In addition, samples 4, 5, 7, 13, 14, 20, 21, 23, 26, 27, 29, and 30 in which the tin amount and the antimony amount are surrounded by ABCH in FIG. Since the amount of is in a wide range, it can be manufactured under simple management conditions.

  In addition, samples 4 to 8, 11 to 17, 20, 21, 23, 26, 27, 29, and 30 in which the tin amount and the antimony amount are surrounded by ABCDEF in FIG. 1 have a latent heat of solidification exceeding 72 J / g. ing. On the other hand, sample 24, which is a conventional copper base alloy for casting considering corrosion resistance, has a latent heat of solidification of 72 J / g. For this reason, samples 4-8, 11-17, 20, 21, 23, 26, 27, 29, and 30 have larger solidification latent heat and better molten metal flowability than sample 24.

  In particular, Samples 4 to 7 and 11 to 17 in which the tin amount and the antimony amount are surrounded by AGEF in FIG. 1 have a solidification latent heat of 78 J / g or more, and the molten metal flowability is better.

  Therefore, according to the copper base alloy for casting of this invention, it turns out that the more superior dezincing resistance and castability can be exhibited. In addition, since this copper-based alloy for casting is excellent in dezincing resistance, dezincification corrosion due to water such as tap water hardly occurs, and it does not easily fall into a water stoppage failure. For this reason, even if this copper-based alloy for casting is used in a water-stopping portion made of a copper alloy typified by a thermo faucet or the like and a rubber packing, its excellent dezincing resistance makes it an excellent water A stopper may be constructed.

  While the present invention has been described with reference to the embodiments, it is needless to say that the present invention is not limited to the above-described embodiments and can be appropriately modified and applied without departing from the spirit thereof.

  The present invention can be used for water supply equipment such as a faucet fitting.

Claims (2)

A copper-based alloy for casting containing copper, zinc, tin and antimony as a main component,
The amount of tin and the amount of antimony are 0.015 mass% for antimony and 0.013 to 0.203 mass% for tin and 0.203 for tin in a coordinate system in which the tin amount and the antimony amount are expressed in mass%. And a straight line of 0.015 to 0.047% by mass of antimony, 0.047% by mass of antimony and 0.047 to 0.203% by mass of tin, 0.047% by mass of tin and antimony Is 0.047 to 0.141% by mass, antimony is 0.141% by mass and tin is 0.013 to 0.047% by mass, tin is 0.013% by mass and antimony is 0.015%. within the range surrounded by the straight line ～0.141 wt% (inclusive.) der is,
Lead is 2.0 ± 0.2 mass%, iron is 0.11 ± 0.05 mass%, nickel is 0.5-1.0 mass%, aluminum is 0.4 ± 0.1 mass%, zinc is 36.0 ± 0.5 wt%, casting copper based alloys and the balance copper der Rukoto.   The copper-based alloy for casting according to claim 1, wherein tin is 0.013-0.047 mass% and antimony is 0.015-0.141 mass%.

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