JP5953432B2 - Copper base alloy - Google Patents

Description

  The present invention relates to a copper-based alloy, and particularly to a brass alloy excellent in dezincing resistance, erosion / corrosion resistance, stress corrosion cracking resistance, etc., suitable for parts that come into contact with water such as a faucet or a valve. .

Among copper-based alloys, bronze alloys are excellent in dezincing resistance, erosion / corrosion resistance and stress corrosion cracking resistance as cast, but are more expensive than brass alloys and can be used as a substitute for bronze alloys. In recent years, the need for has increased.
As an alloy excellent in corrosion resistance in Patent Document 1, at least one of Sn 0.05 to 0.2% by weight, Sb, As or P, or two of a copper alloy composed of two phases of an α phase and a β phase. A copper alloy containing 0.05 to 0.3% by weight, having a maximum erosion depth of 200 μm or less (JBMA test) and a solidification temperature range of 17 ° C. or less is disclosed.
However, the alloy disclosed in Patent Document 1 can maintain dezincification corrosion resistance by heat treatment.
In addition, the parts used for the part where the flow velocity is high, such as a faucet, have insufficient erosion / corrosion resistance, and the fields that can be used are limited.
In Patent Document 2, in terms of mass ratio, 61.2 ≦ Cu <64.0%, Sn: 0.8-2.0%, Sb: 0.04-0.15%, Al: 0.4-0. 7%, Pb: 0.5 to 3.0%, B: 1 to 200 ppm, the balance is made of Zn and inevitable impurities, and heat treatment is performed by adding Ni: 0.2 to 1.0% by mass ratio. There has been disclosed an alloy in which the dezincing resistance is improved and the ISO maximum dezincification corrosion depth is ensured to 200 μm or less by refining macro crystal grains.
However, although the alloy disclosed in Patent Document 2 has cleared the ISO maximum dezincification corrosion depth of 200 μm or less due to the refinement effect by B and Fe, sand casting is generally used for melting in the air without using a molten metal coating material. Then, the amount of B to be added is large, and an intermetallic compound is formed by B and Fe, which may deteriorate the polishing properties.
In particular, in the faucet fitting plated after polishing, the generation of an intermetallic compound of B and Fe is fatal.
Further, the ISO maximum dezincification corrosion depth of 200 μm is a standard value as a dezincing-resistant material, which is a standard lower limit value, and generally 100 μm or less is desired.
Furthermore, the copper-based alloy disclosed in the publication has substantially Ni as a necessary element as described in the examples.
However, since Ni is an environmentally hazardous substance and is expected to be added to the water quality standard soon, it is not preferable to add Ni to casting materials used for faucets and valves.

Japanese Patent No. 3461081 Japanese Unexamined Patent Publication No. 2009-263787

  An object of this invention is to provide the copper base alloy which consists of a brass alloy excellent in dezincing resistance etc., without heat-processing.

The copper-based alloy according to the present invention is excellent in dezincification corrosion resistance without heat treatment, and is excellent in erosion / corrosion resistance and stress corrosion cracking resistance. There are two types of copper-based alloys. First, as a Pb-based copper-based alloy, Cu: 63.5 to 69.0%, Sn: 1.2 to 2.0%, Fe: ≦ 0.15%, Pb: 0.1 to 2.0%, Al: 0.01 to 0.2%, Sb: 0.06 to 0.15%, and P component is Cu: 63. When it is less than 5 to 65.0%, P: 0.04 to 0.15%, Cu: When it is 65.0 to 69.0%, P: ≦ 0.15% The remainder is made of Zn and impurities.
The feature of the present invention is that the copper-based alloy (brass) retains the dezincing resistance of ISO maximum dezincing depth of 100 μm or less without heat treatment without adding B or Ni which are harmful elements to the faucet fitting. is there.
Regarding the stress corrosion cracking resistance, the cast material has a feature that cracks are difficult to progress because there is no crystal orientation.

  Moreover, the copper base alloy suitable for casting according to the present invention is, in mass%, Cu: 63.5 to 69.0%, Sn: 1.2 to 2.0%, Fe: ≦ 0.15%, Pb: 0.1 to 2.0%, Al: 0.01 to 0.2%, Sb: 0.06 to 0.15%, P component is Cu: 63.5 to 65.0 %: P: 0.04 to 0.15%, Cu: 65.0 to 69.0%, P: ≦ 0.15% is an optional additive component, Te: 0.0. 01 to 0.45%, Se: 0.02 to 0.45%, at least one element or / and Mg: 0.001 to 0.2%, Zr: 0.005 to 0.2% Among them, it contains at least one element and the balance is made of Zn and impurities.

  Next, as the Bi-based copper-based alloy according to the present invention, in mass%, Cu: 63.5 to 69.0%, Sn: 1.2 to 2.0%, Fe: ≦ 0.15%, Bi: 0.5 to 1.5%, Al: 0.01 to 0.2%, Sb: 0.06 to 0.15%, P component is Cu: 63.5 to 65.0 Is less than%, P: 0.04 to 0.15%, Cu: 65.0 to 69.0%, P: ≤ 0.15% of any additive component, the balance is Zn It consists of impurities.

  Moreover, in mass%, Cu: 63.5-69.0%, Sn: 1.2-2.0%, Fe: ≦ 0.15%, Bi: 0.5-1.5%, Al: 0 0.01% to 0.2%, Sb: 0.06% to 0.15%, and when Cu is less than 63.5% to 65.0%, P: 0.04% to 0.15% , Cu: 65.0 to 69.0%, P: ≦ 0.15% is an optional additive component, Te: 0.01 to 0.45%, Se: 0.02 to 0.05%. 45% of at least one element or / and Mg: 0.001 to 0.2%, Zr: 0.005 to 0.2% of at least one element, with the balance being Zn And impurities.

The brass alloy according to the present invention can be used as an alternative to a bronze alloy.
An alloy used for contact with water can clear the ISO maximum dezincification corrosion depth of 100 μm or less without heat treatment without adding harmful elements such as Ni and B.
It also has excellent erosion / corrosion resistance and stress corrosion cracking resistance.

The component table | surface and evaluation result of the copper base alloy used for evaluation are shown. The component table | surface and evaluation result of the copper base alloy used for evaluation are shown. A sample collection diagram is shown. The test method of erosion corrosion is shown.

Hereinafter, the components of the copper-based alloy in the present invention will be described.
The Cu component is preferably in the range of 63.5 to 69.0%.
If the Cu component is less than 63.5%, the β phase increases and the corrosion resistance decreases.
Increasing the Cu component improves the corrosion resistance such as dezincification corrosion resistance, but it is preferably in the range of 63.5 to 69.0% because it becomes expensive and the strength decreases.

Pb is an additive element for improving the machinability, and in the present invention, if necessary, it contains 0.1% or more, but if it exceeds 2.0%, the strength may decrease. 2.0% or less.
Further, from the viewpoint of improving machinability, 0.5 to 1.5% Bi may be contained instead of Pb.

Sn is an element necessary for ensuring dezincing resistance and erosion / corrosion resistance. In order to obtain the erosion / corrosion resistance equivalent to that of a bronze material, the Sn content needs to be 1.2% or more, more preferably 1.5% or more.
On the other hand, when the Sn content exceeds 2.0%, even if the dezincing resistance is good, the elongation value decreases among the mechanical properties when used as cast. From the viewpoint of securing the elongation value, it is more preferably 1.8% or less. Therefore, the range of Sn is 1.2 to 2.0%, more preferably 1.5 to 1.8%.

  Fe is preferable to be 0.15% or less because it easily forms a compound with P and reduces the effect of P.

Al is contained for preventing oxidation of P.
In order to prevent oxidation of P, it is necessary to contain at least 0.01%.
Further, when Al is 0.2% or more, dezincing resistance is reduced in the range of this component, so the Al range is set to 0.01 to 0.2%.
From the viewpoint of dezincing resistance, it is more preferably 0.01 to 0.1%.
Al is also effective in improving the hot water flow, but this level of Al content is sufficient to maintain the same hot water flow as bronze.

Sb is contained in order to improve the dezincing resistance.
In order to ensure that the ISO maximum dezincing depth is 100 μm or less without heat treatment, it is necessary to contain 0.3% or more in the γ phase.
For that purpose, the content of at least 0.06% is necessary.
Moreover, since it will embrittle if it exceeds 0.15%, the content range of Sb was made into 0.06 to 0.15%.
More preferably, it is 0.08 to 0.13% in terms of both dezincing resistance and mechanical properties.

P is contained together with Sb in order to improve the dezincing resistance. However, it is an essential element when Cu is less than 65%, but an optional element when Cu is 65% or more.
In order to ensure that the ISO maximum dezincing depth is 100 μm without heat treatment, when Cu is less than 65%, it is necessary to contain at least 0.04%.
More preferably, it is 0.06% or more.
On the other hand, if it exceeds 0.15%, segregation is likely to occur if it is cast, so the range was 0.04 to 0.15%.
In addition, even if P is not contained when Cu is 65% or more, it is excellent in dezincing resistance, and may be arbitrarily added within a range of 0.15% or less.

  The Te component improves the machinability, but is effective at 0.01% or more, and when added from the point of obtaining an effect corresponding to the amount added and economical, the upper limit was 0.45%.

The Se component improves machinability, but is suppressed as much as possible because the material unit price is expensive.
Moreover, since hot workability worsens, 0.45% or less is desirable.
When adding Se component, the range of 0.02 to 0.45% is preferable.

The Mg component has the effect of improving the strength by refining crystal grains, improving the flowability of hot water, and deoxidizing / desulfurizing effects.
When 0.001% or more of Mg is contained in the molten metal, the S component in the molten metal is removed in the form of MgS.
On the other hand, if Mg exceeds 0.2%, it is oxidized, and the viscosity of the molten metal is increased, which may cause casting defects such as oxide entrainment.
Therefore, when adding the Mg component, an effect is recognized in the range of 0.001 to 0.2%.

The Zr component has a crystal grain refining effect.
The effect appears with addition of 0.005% or more.
Zr has a strong affinity for oxygen, and when it exceeds 0.2%, it oxidizes, increasing the viscosity of the molten metal, and may cause casting defects such as oxide entrainment.
Therefore, when adding Zr, it is 0.005 to 0.2% of range.

As a test material, melts having various alloy compositions as shown in the tables of FIGS. 1 and 2 were prepared, and poured into a JIS H5120 A test material (sand mold) as shown in FIG. Solidified), and the sample was collected by carrying out frame separation.
In addition, although there exist No. A, No. B, etc. in the casting die used as a test material, it checked with the No. A test material this time.
The balance Zn in the table also contains inevitable impurities.
<Evaluation test>
(1) Dezincing resistance test The test piece sampling position shown in FIG. 3 was cut out, and the test material was added to a 12.7 g / l solution of CuCl ₂ .2H ₂ O at 75 ± 3 ° C. according to ISO 24. It was immersed for a time, the dezincification corrosion depth was measured, and evaluated according to the following criteria.
Those having a dezincification depth of 100 μm or less were accepted, and those having a dezincification depth exceeding 100 μm were rejected.
In this evaluation test, the evaluation was evaluated more strictly than the ISO standard of 200 μm or less.
(2) Tensile test A JIS Z 2201 No. 4 specimen taken from JIS H5120 A specimen (sand mold) and machined was subjected to a tensile test using an Amsler universal testing machine.
A sample having a strength exceeding 200 MPa was marked with ◯, and a sample having a strength less than 200 MPa was marked with ×.
A product with an elongation exceeding 15% was marked with ◎, a material with elongation exceeding 12% was marked with ○, and a material with elongation less than 12% was marked with ×.
(3) Erosion / corrosion evaluation test Using a test apparatus as shown in FIG. 4, the test liquid is jetted onto the surface of the test piece, and the shear force generated by the disturbance of the test liquid flowing through the gap between the test piece and the nozzle The erosion-corrosion was forcibly generated, and the maximum corrosion wear depth and corrosion form were evaluated.
Test liquid: CuCl ₂ · 2H ₂ O (12.7 g / 1000 ml)
Test temperature: 40 ° C
・ Flow rate: 0.2 l / min
・ Maximum flow velocity: 0.62 m / sec
・ Test time: 7 hours

The evaluation results are shown in the tables of FIGS.
The strength indicates the evaluation result of the tensile strength by the above tensile test, and the elongation is also evaluated based on the above criteria.
Dezincing depth indicates a specific measured value, and its unit is μm.
Inventive alloys Examples 1 to 20 and 27 to 47 show Pb-based brass alloys, and Examples 21 to 24 and 48 to 69 show Bi-based brass alloys.
Examples 25 and 26 are Pb-based alloys to which P is not added.
In any of these, each component was included in a predetermined range, and it was excellent in dezincing resistance without heat treatment.
In Example 47, since the quality target is clear even if the Cu component is 69.34%, it is estimated that there is no problem even if the Cu component exceeds 69.0%.
In Example 39, the quality target was cleared even when the Pb component was 2.10%. Therefore, there is no problem even if the Pb component slightly exceeds 2.0%.
On the other hand, Comparative Examples 101 and 102 were inferior in dezincing resistance because the Cu component was less than 63.5% and Al was more.
Also, the growth did not reach the target.
In particular, Comparative Example 113 did not contain P and Sb, and was inferior in dezincing resistance.
In Comparative Examples 103 to 107, since the Sn component exceeds 2.0%, even though the dezincing resistance is good, the elongation does not reach the target.
In Comparative Examples 108 and 109, the Cu component was less than 63.5%, and 110 was inferior in dezincing resistance because Al was higher than 0.2%.
In Comparative Example 111, Sn exceeded 2%, so the growth could not achieve the target.
Moreover, since the comparative example 112 was less than 65% of Cu and did not contain P, the dezincing resistance was inferior.

Next, an erosion / corrosion evaluation test was conducted.
Samples were also evaluated for comparison, invention alloy 3, alloy of comparative example 113 and bronze material (CAC406C: Sn: 3.67%, Zn: 5.76%, Pb: 4.20%, balance Cu). .
As a result, at the maximum corrosion wear depth, the invention alloy 3 was 66 μm, the comparative example 113 was 700 μm, and the bronze material was 63 μm.
Further, the corrosion form of the invention alloy 3 was laminar, while the comparative example 113 was cyclic.
The bronze material was layered.
From this, it became clear that the brass alloy according to the present invention can be sufficiently used as a substitute for a bronze alloy.

The copper-based alloy according to the present invention can be widely applied to water-based products that require high dezincing resistance and erosion / corrosion resistance.
Moreover, it is useful for cost reduction of the conventional brass alloy in that heat treatment after casting is not required.

Claims (4)

In mass%, Cu: 63.5-69.0%, Sn: 1.2-2.0%, Fe: ≦ 0.15%, Pb: 0.1-2.0%, Al: 0.01 -0.2%, Sb: 0.06-0.15% of range,
The P component is P: 0.04 to 0.15% when Cu: 63.5 to less than 65.0%, and P: ≤ 0.15% when Cu: 65.0 to 69.0%. Is an optional additive component in the range,
A copper-base alloy characterized in that the balance consists of Zn and impurities. In mass%, Cu: 63.5-69.0%, Sn: 1.2-2.0%, Fe: ≦ 0.15%, Pb: 0.1-2.0%, Al: 0.01 -0.2%, Sb: 0.06-0.15% of range,
The P component is P: 0.04 to 0.15% when Cu: 63.5 to less than 65.0%, and P: ≤ 0.15% when Cu: 65.0 to 69.0%. Is an optional additive component in the range,
Te: 0.01 to 0.45%, Se: 0.02 to 0.45%, at least one element or / and Mg: 0.001 to 0.2%, Zr: 0.005 A copper-based alloy containing 0.2% of at least one element, the balance being Zn and impurities. In mass%, Cu: 63.5-69.0%, Sn: 1.2-2.0%, Fe: ≦ 0.15%, Bi: 0.5-1.5%, Al: 0.01 -0.2%, Sb: 0.06-0.15% of range,
The P component is P: 0.04 to 0.15% when Cu: 63.5 to less than 65.0%, and P: ≤ 0.15% when Cu: 65.0 to 69.0%. Is an optional additive component in the range,
A copper-base alloy characterized in that the balance consists of Zn and impurities. In mass%, Cu: 63.5-69.0%, Sn: 1.2-2.0%, Fe: ≦ 0.15%, Bi: 0.5-1.5%, Al: 0.01 -0.2%, Sb: 0.06-0.15% of range,
The P component is P: 0.04 to 0.15% when Cu: 63.5 to less than 65.0%, and P: ≤ 0.15% when Cu: 65.0 to 69.0%. Is an optional additive component in the range,
Te: 0.01 to 0.45%, Se: 0.02 to 0.45%, at least one element or / and Mg: 0.001 to 0.2%, Zr: 0.005 A copper-based alloy containing 0.2% of at least one element, the balance being Zn and impurities.

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