JP2017206736A - Copper-based alloy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-based alloy achieving both of corrosion resistance and castability while suppressing a nickel amount.SOLUTION: The copper-based alloy having zinc equivalent of 36.0-48.0 mass%, nickel (Ni) of 0.001-0.1 mass%, zinc (Zn) of 30.0-43.0 mass%, lead (Pb) of 0.01-3.0 mass%, aluminum (Al) of 0.10-1.50 mass%, tin (Sn) of 0.001-0.1 mass%, iron (Fe) of 0.001-0.3 mass%, boron (B) of 0.0003-0.003 mass%, antimony (Sb) of 0.01 mass% or more with satisfying the following formula (1). Antimony (Sb) amount (mass%)≥0.04×(zinc equivalent-37.5) (1).SELECTED DRAWING: None

Description

  The present invention relates to a copper base alloy.

  Conventional copper-based alloys contain about 0.9% by mass of nickel, which is an allergen metal, and nickel was eluted into tap water (see Patent Document 1). When dealing with the possibility of stricter regulations regarding drinking water, it is conceivable to suppress the nickel content in the copper-based alloy in order to suppress the elution of nickel.

JP 2010-242210 A

However, when the amount of nickel in the copper-based alloy is reduced, it is difficult to achieve both corrosion resistance and castability.
Nickel has the effect of reducing the zinc equivalent of the copper-based alloy. In general, when the zinc equivalent is reduced, the corrosion resistance of the copper-based alloy is improved. Therefore, if the amount of nickel in the copper-based alloy is reduced, the zinc equivalent cannot be reduced, and as a result, it becomes difficult to ensure the corrosion resistance of the copper-based alloy.
Moreover, nickel has the effect | action which improves the mechanical strength (strength and elongation) of a copper base alloy. Therefore, if the amount of nickel in the copper-based alloy is reduced, the mechanical strength cannot be ensured when the zinc equivalent is reduced, and as a result, the castability is lowered.
Therefore, it is difficult to easily reduce the amount of nickel in order to achieve both corrosion resistance and castability of the copper base alloy.

  This invention is made | formed in view of the said conventional situation, Comprising: While suppressing the amount of nickel, it aims at providing the copper base alloy which was compatible with corrosion resistance and castability.

In view of the prior art, the present inventors have developed a new copper-based alloy as a result of intensive studies.
And the copper base alloy discovered the unexpected fact that corrosion resistance and castability can fully be ensured, suppressing nickel amount. The present invention has been made based on this finding.

That is, the invention described in claim 1
Copper group containing copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), aluminum (Al), tin (Sn), iron (Fe), boron (B), antimony (Sb) An alloy,
The zinc equivalent is 36.0 to 48.0% by weight,
Nickel (Ni) is 0.001 to 0.1 mass%,
Zinc (Zn) is 30.0-43.0% by mass,
Lead (Pb) is 0.01-3.0 mass%,
Aluminum (Al) is 0.10-1.50 mass%,
Tin (Sn) is 0.001 to 0.1 mass%,
Iron (Fe) is 0.001 to 0.3 mass%,
Boron (B) is 0.0003 to 0.003 mass%,
Antimony (Sb) is 0.01 mass% or more,
And satisfy | fills following formula (1),
The balance is copper (Cu) and an inevitable impurity, which is a copper-based alloy.

Antimony (Sb) amount (% by mass) ≧ 0.04 × (zinc equivalent-37.5) (1)

The invention described in claim 2
Antimony (Sb) satisfy | fills following formula (2), It is a copper base alloy of Claim 1 characterized by the above-mentioned.

Antimony (Sb) content (mass%) ≤ 0.03 + 0.04 x (zinc equivalent-36.0) (2)

  Invention of Claim 3 is a copper base alloy of Claim 1 or 2 whose zinc equivalent is 38.2-48.0 mass%.

  The invention according to claim 4 further includes the group consisting of arsenic (As), cobalt (Co), magnesium (Mg), phosphorus (P), selenium (Se), silicon (Si), and zirconium (Zr). The copper-based alloy according to any one of claims 1 to 3, wherein the element contains at least one element selected from 0.01% by mass to 1% by mass.

  In addition, in this invention, when elements other than zinc are added to brass in the present invention, the element content is converted to Zn (mass%), and it is as if a Cu-Zn binary brass alloy. It is a value unique to each element that interprets as follows. In the present invention, the zinc equivalent proposed by Guillet is used and is obtained by the following calculation formula (reference: casting technology series 5, production technology of copper alloy castings, P58 to 59 issued by Foundation Materials Center).

A: Actual Cu content (% by mass) in the alloy
B: Actual Zn content (% by mass) in the alloy
q: Content of elements other than Cu and Zn (% by mass)
t: zinc equivalent of elements other than Cu and Zn

The zinc equivalent coefficient of each element is shown below. The zinc equivalent coefficient of elements excluding the following and Cu is set to “1.0”.
Pb: 1.0
Sn: 2.0
Al: 6.0
Ni: -1.3
Si: 10.0
Fe: 0.9
Mn: 0.5
Mg: 2.0

  According to the copper base alloy of the present invention, corrosion resistance and castability can be secured while suppressing the amount of nickel.

It is a top view of the metal mold | die for a both-ends restraint test used for castability evaluation. It is a figure which shows the cross-sectional photograph of the test piece with favorable corrosion resistance by an evaluation test. It is a figure which shows the cross-sectional photograph of the test piece with bad corrosion resistance by an evaluation test. It is a figure which shows the photograph of the test piece with favorable castability by an evaluation test. It is a figure which shows the photograph of the test piece with favorable castability by an evaluation test. It is a figure which shows the photograph of the test piece with bad castability by an evaluation test. It is a figure which shows the photograph of the test piece with bad castability by an evaluation test. It is an image which shows distribution of zinc (Zn) in the copper base alloy which is one of the Examples. It is an image which shows distribution of the antimony (Sb) in the copper base alloy which is one of the Examples.

A preferred embodiment of the present invention will be described.
Hereinafter, embodiments for carrying out the present invention will be described in detail based on each test with reference to the drawings and tables. In addition, the structure described below is an illustration and does not limit the scope of the present invention at all.

Hereinafter, the components of the copper-based alloy in the present invention will be described.
A zinc equivalent is 36.0-48.0 mass%. A zinc equivalent becomes like this. Preferably it is 36.0-42.0 mass%, More preferably, it is 38.2-42.0 mass%, More preferably, it is 39.5-41.5 mass%. When the zinc equivalent is within this range, the formation of the γ phase is suppressed, and the strength and corrosion resistance are excellent.

  Nickel (Ni) is 0.001 to 0.1% by mass, preferably 0.03 to 0.09% by mass, and more preferably 0.06% by mass. This is because if nickel (Ni) is within this range, elution of nickel into water can be suppressed as much as possible.

  Zinc (Zn) is 30.0 to 43.0% by mass, preferably 32 to 41% by mass, more preferably 35 to 40% by mass, and still more preferably 36 to 38% by mass. When zinc (Zn) is within this range, the mechanical strength is excellent, and it is easy to achieve both corrosion resistance and castability.

  Lead (Pb) is 0.01 to 3.0% by mass, preferably 0.80 to 2.45% by mass, more preferably 1.40 to 2.20% by mass, and still more preferably 1 .80 to 2.20 mass%. When lead (Pb) is within this range, the machinability is excellent. Moreover, when lead (Pb) exceeds 3.0 mass%, it exists in the tendency for intensity | strength to fall.

  Aluminum (Al) is 0.10 to 1.50% by mass, preferably 0.10 to 1.20% by mass, more preferably 0.30 to 0.90% by mass, and still more preferably 0. .30 to 0.50 mass%. When the aluminum (Al) is within this range, the acid resistance and erosion resistance are excellent.

  Tin (Sn) is 0.001-0.1 mass%, Preferably it is 0.01-0.09 mass%, More preferably, it is 0.01-0.05 mass%. When tin (Sn) is within this range, sufficient forgeability and corrosion resistance can be obtained.

  Iron (Fe) is 0.001 to 0.3% by mass, preferably 0.03 to 0.20% by mass, more preferably 0.06 to 0.15% by mass, and still more preferably 0. 0.06 to 0.12% by mass. When iron (Fe) is within this range, hardness and strength increase, and high temperature strength is excellent.

  Boron (B) is 0.0003 to 0.003% by mass, preferably 0.0006 to 0.0030% by mass, more preferably 0.0006 to 0.0020% by mass, and still more preferably. It is 0.0006-0.0012 mass%. If boron (B) is within this range, the transition at the time of casting is delayed, so the strength at high temperature is excellent.

Antimony (Sb) is 0.01% by mass or more and satisfies the following formula (1). Antimony (Sb) is preferably 0.03 to 0.43% by mass, more preferably 0.03 to 0.25% by mass, and still more preferably 0.09 to 0.20% by mass. When antimony (Sb) is within this range, corrosion resistance and castability are excellent.

Antimony (Sb) amount (% by mass) ≧ 0.04 × (zinc equivalent-37.5) (1)

  In the present invention, the balance is copper (Cu) and inevitable impurities. Inevitable impurities are metal products that exist in raw materials or are inevitably mixed in the manufacturing process. It is an acceptable impurity because it is a trace amount and does not affect the properties of the metal product. In the present invention, the impurity is less than 0.1% by mass.

  In the present invention, one kind selected from the group consisting of arsenic (As), cobalt (Co), magnesium (Mg), phosphorus (P), selenium (Se), silicon (Si), and zirconium (Zr). The above elements can be contained in an amount of 0.01% by mass to 1% by mass. Even if these are contained, the copper base alloy of the present invention is excellent in corrosion resistance and castability.

  Hereinafter, the present invention will be described more specifically with reference to examples.

1 [Sample preparation]
Ingots composed of Examples 1 to 21 and Comparative Examples 1 to 9 having compositions shown in Tables 1 to 5 described below were produced by a known method. And using the ingot of each Example and each comparative example, the castability evaluation test and the dezincification corrosion resistance evaluation test were done.

2 [Test]
(Dezincification corrosion resistance evaluation test)
The test was performed based on the dezincification corrosion test method of brass specified in ISO6509 using the test piece produced from each ingot. About the corrosion resistance of Tables 1-5, the average depth of a dezincification layer is shown. The shallower the depth, the better the corrosion resistance.

(Castability evaluation)
Castability was evaluated by the arrow restraint test method. FIG. 1 is a plan view of a both-end restraint test mold used for castability evaluation. In this test method, a die for both ends restraint test shown in FIG. 1 was used. This metal mold has a rectangular central mold 11 provided at the center and a pair of rectangular constraining molds 12a and 12b provided at both ends. The central mold 11 and the constraining molds 12a and 12b are made of S45C. These are combined together and fixed to each other by a bolt (not shown) to form a mold.

  A square recess 13 is formed at the center of the central mold 11. Further, the central mold 11 is formed with a groove 14 that communicates with the recess 13 and extends in the width direction. The recess 13 and the groove 14 have the same depth. The recess 13 is filled with a heat insulating material 16 made of casting sand and a resin component as a binder except for a portion 15 communicating with the groove 14.

  The central mold 11 is formed with a groove 17 communicating with the groove 14 and the portion 15. The constraining dies 12a and 12b are formed with triangular recesses 18a and 18b communicating with the ends of the groove 14, the portion 15 and the groove 17, respectively. The depths of the grooves 17 and the recesses 18a and 18b are also the same as the recesses 13 and the grooves 14. A double arrow-shaped cavity is formed by the groove 14, the portion 15, the groove 17, and the recesses 18a and 18b.

  An alloy melt 19 according to the example and the comparative example was poured into the mold cavity. In the process in which the molten metal 19 in the cavity is cooled and solidified, the recesses 18a and 18b are restrained, and a solidification contraction force is generated. The central portion of the molten metal 19 in the cavity is delayed by the heat insulating material 16 as compared with the recesses 18a and 18b and becomes a final solidified portion, and the solidification shrinkage force is concentrated. Castability was evaluated by the presence or absence and degree of cracking at the central portion.

  Regarding the castability of Tables 1 to 5, in the linear cavity formed from the groove 14, the part 15 and the groove 17 (not including the recesses 18a and 18b), an experiment was performed by gradually lengthening the cavity. The length at which cracking occurred for the first time is shown. The longer this length, the better the castability.

(Element distribution)
The element distribution of the copper-based alloy according to Example 10 which is an example of the present embodiment was measured using an EPMA (Electron Probe Micro Analyzer).

3 [Result]
The result of the dezincification corrosion resistance evaluation test of Examples 1-21 and Comparative Examples 1-9, and the evaluation result of castability are shown with a composition.
In addition, the Sb lower limit in each table is a value obtained by substituting the zinc equivalent of each sample into the following formula.
(Sb lower limit)

Antimony (Sb) amount (% by mass) = 0.04 × (zinc equivalent-37.5)

The upper limit of Sb in each table is a value obtained by substituting the zinc equivalent of each sample into the following formula.
(Sb upper limit)

Antimony (Sb) amount (% by mass) = 0.03 + 0.04 x (zinc equivalent-36.0)

Here, the correspondence between each claim and the examples and comparative examples will be described. The correspondence is as follows.
Examples 1 to 12 satisfy the requirements of claims 1, 2, and 3.
Examples 13 to 16 satisfy the requirements of claims 1 and 3. However, Examples 13 to 16 do not meet the condition of the above formula (2) and do not satisfy the requirement of claim 2.
Examples 17 to 19 are examples that satisfy the configurations of claims 1 and 2. However, Examples 17 to 19 have a zinc equivalent of less than 38.2 and do not satisfy the requirement of claim 3.
Examples 20 to 21 are examples that satisfy the configurations of claims 1, 2, 3, and 4.
The comparative example does not meet the condition of the above formula (1) and does not satisfy the requirements of any claims.

  Moreover, the ratio of β phase in each table was obtained from observation of the metal structure. For the metal structure, the cut surface of the sample was mirrored, etched with an aqueous solution in which hydrochloric acid and ferric chloride were mixed, and observed with an optical microscope to determine the area ratio (%) of the α phase and β phase.

(Dezincification corrosion resistance evaluation test)
FIG. 2 is a diagram showing a cross-sectional photograph of the test piece of Example 3 with good corrosion resistance by the evaluation test, and FIG. 3 is a diagram showing a cross-sectional photograph of the test piece of Comparative Example 2 with poor corrosion resistance by the evaluation test.
From the results of Tables 1 to 5, in any example in which antimony (Sb) is 0.01% by mass or more and satisfies the following formula (1), the average depth of the dezincification layer is 100 μm or less, It showed good corrosion resistance.

Antimony (Sb) amount (% by mass) ≧ 0.04 × (zinc equivalent-37.5) (1)

  In Comparative Examples 1 to 9, none of the above formula (1) was satisfied, the average depth of the dezincification layer was 100 μm or more, and the evaluation of corrosion resistance was low.

(Castability evaluation results)
FIGS. 4 to 5 illustrate photographs of samples that did not crack at a predetermined length. 4 is taken from an oblique direction, and FIG. 5 is taken from the top. As can be seen from these photographs, it is not cracked at the center, and it can be evaluated that the castability is good.
FIGS. 6 to 7 illustrate photographs of samples with cracks having a predetermined length. 6 is taken from an oblique direction, and FIG. 7 is taken from above. As can be seen from these photographs, it is cracked at the center and it can be evaluated that the castability is poor.

From Tables 1-5, Examples 1-21 which satisfy | fill Formula (1) were 150 mm, and there was no crack, and the castability was a practical level.
In particular, the zinc equivalent was 38.2 to 48% by mass, and Examples 1 to 12 satisfying the formula (2) were not cracked even when the thickness was 200 mm or more, and the castability was particularly good.

Antimony (Sb) content (mass%) ≤ 0.03 + 0.04 x (zinc equivalent-36.0) (2)

  Further, focusing on the zinc equivalent, Examples 1 to 12 having a zinc equivalent of 38.2 to 48% by mass were found to have better castability than Examples 17 to 19 having a zinc equivalent of less than 38.2. It was.

(Result of element distribution)
8 to 9 show the results of elemental analysis. FIG. 8 is an image showing the distribution of zinc (Zn) in the copper-based alloy which is one of the examples, and FIG. 9 is an image showing the distribution of antimony (Sb) in the copper-based alloy which is one of the examples. is there. Note that the images shown in FIGS. 8 and 9 are obtained by capturing the same region of the same sample.

  In FIG. 8, a bright region has relatively little zinc (Zn) and suggests an α phase, and a dark region has relatively much zinc (Zn) and suggests a β phase. On the other hand, in FIG. 9, the bright part shows antimony (Sb). 8 to 9, it can be seen that antimony (Sb) is preferentially taken into the β phase. When the composition of the example of the present invention is adopted, it is considered that antimony (Sb) is preferentially taken into the β phase and the corrosion resistance is improved. On the other hand, it is considered that good castability can be secured because the zinc equivalent does not decrease.

From the results of the various tests described above, it was confirmed that the copper-based alloy of this example was excellent in both corrosion resistance and castability.
In addition, this invention is not limited to the Example demonstrated with the said description and drawing.

  Although the present invention can be used for a wide range of applications, it can be suitably used for water supply equipment such as water supply fittings, drainage fittings and valves. In addition, since the present invention has good castability, it is generally molded by casting the material of the present invention dissolved in a mold using a mold or sand mold, and the molded product is processed by cutting, polishing, or plating. Get. In addition, because of its good castability, it may be a cutting bar or a forging bar that is formed by extrusion after continuous casting.

DESCRIPTION OF SYMBOLS 11 ... Center type 12a, 12b ... Restraint type 13 ... Recessed part 14 ... Groove 16 ... Heat insulating material 17 ... Groove 18a, 18b ... Recessed part 19 ... Molten metal

Claims (4)

Copper group containing copper (Cu), nickel (Ni), zinc (Zn), lead (Pb), aluminum (Al), tin (Sn), iron (Fe), boron (B), antimony (Sb) An alloy,
The zinc equivalent is 36.0 to 48.0% by weight,
Nickel (Ni) is 0.001 to 0.1 mass%,
Zinc (Zn) is 30.0-43.0% by mass,
Lead (Pb) is 0.01-3.0 mass%,
Aluminum (Al) is 0.10-1.50 mass%,
Tin (Sn) is 0.001 to 0.1 mass%,
Iron (Fe) is 0.001 to 0.3 mass%,
Boron (B) is 0.0003 to 0.003 mass%,
Antimony (Sb) is 0.01 mass% or more,
And satisfy | fills following formula (1),
A copper base alloy characterized in that the balance is copper (Cu) and inevitable impurities.

Antimony (Sb) amount (% by mass) ≧ 0.04 × (zinc equivalent-37.5) (1)
Antimony (Sb) satisfy | fills following formula (2), The copper base alloy of Claim 1 characterized by the above-mentioned.

Antimony (Sb) content (mass%) ≤ 0.03 + 0.04 x (zinc equivalent-36.0) (2)
  The copper-based alloy according to claim 1 or 2, wherein the zinc equivalent is 38.2 to 48.0 mass%.   Furthermore, one or more elements selected from the group consisting of arsenic (As), cobalt (Co), magnesium (Mg), phosphorus (P), selenium (Se), silicon (Si), and zirconium (Zr), It contains 0.01 to 1 mass%, The copper base alloy as described in any one of Claims 1-3 characterized by the above-mentioned.