WO2015137048A1

WO2015137048A1 - Lead-free brass material and instrument for water supply

Info

Publication number: WO2015137048A1
Application number: PCT/JP2015/054100
Authority: WO
Inventors: 鈴木　宏昌; 継志伊藤; 文康石黒; 佐藤　浩司
Original assignee: 株式会社Ｌｉｘｉｌ
Priority date: 2014-03-13
Filing date: 2015-02-16
Publication date: 2015-09-17
Also published as: JP2015175008A

Abstract

The present invention relates to a lead-free brass material and an instrument for water supply, and provides an alloy material which has achieved a good balance among characteristics such as cutting workability, castability and corrosion resistance. The composition of this alloy material, which is a lead-free brass material, contains selenium in an amount of 0.04-0.58% by mass. In addition, this lead-free brass material contains bismuth in an amount of 0.59-2.44% by mass. It is preferable that this lead-free brass material contains silicon in an amount of 0.30-1.68% by mass.

Description

Lead-free brass material and water supply equipment

The present invention relates to a lead-less brass material and a water supply device.

Conventionally, brass-based alloys are often used for water supply appliances, and some of these alloys contain lead (Pb). There is an undeniable risk that water supply equipment manufactured using an alloy containing lead may be infused into the human body through drinking water or the like when lead is eluted from the alloy. Therefore, in recent years, regulations and the like have been strengthening the reduction of lead and the switching to materials that do not contain lead. On the other hand, lead has been used as a material useful for reducing nests generated during casting and improving cutting workability. Therefore, if the brass material simply does not contain lead or lead is reduced, the desired characteristics cannot be satisfied.

Therefore, a lead-free brass alloy has been devised that bismuth (Bi) is added instead of lead to improve the machinability (see, for example, Patent Document 1).

Japanese Patent No. 3335002

However, the above-described alloys have room for further improvement in castability and corrosion resistance other than machinability.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an alloy material capable of simultaneously satisfying characteristics such as cutting workability, castability, and corrosion resistance.

In order to solve the above problems, the lead-less brass material according to an aspect of the present invention includes copper, zinc, bismuth, selenium, and silicon. This lead-less brass material has a selenium content of 0.04 to 0.58 mass%.

According to this aspect, the castability can be improved while maintaining the machinability to some extent. In addition, lead-free may include not only the case where lead is not completely contained or the case where it is slightly contained as an impurity, but also the case where the lead content is reduced as compared with the conventional case.

The bismuth content may be 0.59 to 2.44% by mass, and the silicon content may be 0.30 to 1.68% by mass. Thereby, corrosion resistance can be improved, maintaining cutting workability to some extent.

Another aspect of the present invention is also a lead-less brass material. This leadless brass material contains copper, zinc, bismuth, selenium and silicon, the selenium content is 0.04 to 0.58% by mass, and the bismuth content is 0.76 to 1.72% by mass. The silicon content is 0.53 to 1.00% by mass.

According to this aspect, cutting workability, castability and corrosion resistance can be achieved at a higher level.

Still another embodiment of the present invention is also a lead-less brass material. This lead-less brass material is a lead-less brass material containing copper, zinc, bismuth, selenium and silicon, and has a selenium content of 0.04 to 0.15 mass% and a bismuth content of 0. It is 76 to 1.00% by mass, and the silicon content is 0.53 to 1.00% by mass.

According to this aspect, the material cost can be reduced while achieving both higher machinability, castability and corrosion resistance.

The lead content may be less than 0.25% by mass. Thereby, it becomes easy to use for water appliances, such as a faucet metal fitting and a water pipe. The lead content is preferably less than 0.15% by weight, more preferably less than 0.10% by weight, and even more preferably less than 0.05% by weight.

Another aspect of the present invention is a water supply device. This water supply device is manufactured using the above lead-less brass material.

According to this aspect, it is possible to obtain a water supply device that is free from defects even if a water supply device having a complicated internal shape and a non-monotonous external shape is manufactured and that is easy to cut.

According to the present invention, it is possible to provide an alloy material that can simultaneously achieve characteristics such as cutting workability, castability, and corrosion resistance.

It is a top view of the metal mold | die for a both-ends restraint test used for castability evaluation. FIG. 2A is a diagram showing a cross-sectional photograph of a test piece with good corrosion resistance by an evaluation test, and FIG. 2B is a diagram showing a cross-sectional photograph of a test piece with poor corrosion resistance by an evaluation test. FIG. 3A is an image showing the distribution of copper (Cu) in a lead-less brass material that is one of the examples, and FIG. 3B is zinc (1) in the lead-less brass material that is one of the examples. It is an image which shows distribution of Zn). FIG. 4A is an image showing the distribution of tin (Sn) in a lead-less brass material that is one of the examples, and FIG. 4B is a bismuth in a lead-less brass material that is one of the examples. It is an image which shows distribution of Bi). FIG. 5A is an image showing the distribution of selenium (Se) in a lead-less brass material which is one of the examples, and FIG. 5B is a diagram showing silicon (1) in the lead-less brass material which is one of the examples. It is an image which shows distribution of Si).

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.

Ingots made of Comparative Examples 1 to 20 and Examples 1 to 45 showing the components of the additive elements shown in Tables 1 and 2 were produced by a general method. Then, using the ingots of each comparative example and each example, a machinability evaluation test, a castability evaluation test, and a dezincification corrosion resistance evaluation test were performed.

(Machinability evaluation test)
Using a rod with a diameter of 26 mm machined from the ingot, the machinability when the outer circumference was machined under the following conditions was evaluated. The conditions are cutting speed: 150 m / min, feed amount: 0.2 mm / rev, and cutting amount: 2 mm. The evaluation method is to measure the resistance value at the time of cutting and use the following formula based on CAC203 which is a cast of brass (containing about 0.5 to 3.0% by mass of lead) (cutting workability index 100). The machinability index was calculated.
Machinability index = (resistance value of CAC203 / resistance value of each bar) × 100

Regarding the machinability of Table 1 and Table 2, the machinability index of 90 or more is indicated by ◯, 80 or more and less than 90 by Δ, and less than 80 by x.

(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 in 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 wax 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.

The molten alloy 19 according to the example and the comparative example was poured into the cavity of this mold. 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 Table 1 and Table 2, the case where there is no crack even when the length of the linear cavity (not including the

recesses

18a and 18b) formed from the groove 14, the portion 15 and the groove 17 is 200 mm or more. ○, a case where there is a crack at 200 mm or more but no crack at 150 mm is Δ, and a case where there is a crack at 150 mm is x.

The judgment results shown in Table 1 and Table 2 are “A” judgments when all three tests are “good”, and “B” judgments are made when only one “△” and three others are “good”. The case where there is at least one x or the case where there are two or more Δs is “C” determination.

(Dezincification corrosion resistance evaluation test)
A test piece prepared from each ingot was used to perform a dezincification corrosion resistance evaluation test based on the Japan Copper and Brass Association Technical Standard (JBMA T303). FIG. 2A is a diagram showing a cross-sectional photograph of a test piece with good corrosion resistance by an evaluation test, and FIG. 2B is a diagram showing a cross-sectional photograph of a test piece with poor corrosion resistance by an evaluation test.

Regarding the corrosion resistance of Tables 1 and 2, the case where the average dezincification depth is less than 50 μm is indicated by ○, the case where the average dezincification depth is 50 μm or more and less than 100 μm, Δ, and the case where the average dezincification depth is 100 μm or more × It is said.

(Element distribution)
Next, the element distribution of the lead-less brass material according to Example 38, which is an example of the present embodiment, was measured using an EPMA (Electron Probe Micro Analyzer). FIG. 3A is an image showing the distribution of copper (Cu) in a lead-less brass material that is one of the examples, and FIG. 3B is zinc (1) in the lead-less brass material that is one of the examples. It is an image which shows distribution of Zn). FIG. 4A is an image showing the distribution of tin (Sn) in a lead-less brass material that is one of the examples, and FIG. 4B is a bismuth in a lead-less brass material that is one of the examples. It is an image which shows distribution of Bi). FIG. 5A is an image showing the distribution of selenium (Se) in a lead-less brass material which is one of the examples, and FIG. 5B is a diagram showing silicon (1) in the lead-less brass material which is one of the examples. It is an image which shows distribution of Si). Each of the images shown in FIGS. 3A to 5B is an image of the same region of the sample.

In each figure, a white (bright) region indicates that the concentration of the corresponding element is relatively high, and a black (dark) region indicates that the concentration of the corresponding element is relatively low. For example, the white areas shown in FIGS. 3A and 3B indicate that a large amount of copper and zinc are present. In particular, a region surrounded by a dotted line in FIG. 3A is a slightly darker region than other white regions. On the other hand, the area surrounded by the dotted line in FIG. 3B corresponding to the area surrounded by the dotted line in FIG. 3A is a brighter area than the other white areas. That is, a region surrounded by a dotted line is a β phase having a relatively large amount of zinc in the brass alloy, and other white regions are an α phase having a relatively large amount of copper.

In addition, the distribution of tin shown in FIG. 4A and the distribution of silicon shown in FIG. 5B are often present in the β phase as shown by the white area surrounded by a dotted line. Recognize. On the other hand, the distribution of bismuth shown in FIG. 4 (b) and the distribution of selenium shown in FIG. 5 (a) are often present in black regions other than the α phase and β phase shown in FIG. 3 (a) and FIG. 3 (b). You can see that

(Difference in performance due to additive elements)
Next, based on the test results of the comparative examples and examples shown in Tables 1 and 2, the influence of elements (particularly bismuth, silicon, selenium) added to brass on each property will be qualitatively described. Table 3 relatively shows the difference in performance depending on the combination of additive elements.

For example, in Comparative Examples 8 to 12 to which bismuth, which is sometimes used as an alternative material for lead, is added, the machinability is good, but the casting crack and the corrosion resistance are not good. This is because bismuth has a lower ability to fill the nest at the time of casting than lead, and the remaining nest at the time of casting becomes the starting point of the casting crack.

Further, in Comparative Examples 13 and 14 to which silicon was added, it was found that the castability and corrosion resistance were good, but the machinability was deteriorated. As shown in FIG. 5B, this is presumably because silicon is present in a large amount in the β phase, which is relatively rich in zinc, and prevents corrosion of the β phase. In addition, the addition of silicon increases the strength and makes it difficult for casting cracks to occur, while the machinability is thought to have deteriorated.

Accordingly, in Comparative Examples 15 to 19 in which both bismuth and silicon are added, there are some which have improved machinability as compared with Comparative Examples 13 and 14 in which only silicon is added. Sex is getting worse. Further, when Comparative Examples 20 to 24 in which both bismuth and selenium are added are seen, although the machinability is improved, the corrosion resistance tends to be poor.

Based on the above findings, the present inventors have conceived that selenium is further added. Specifically, the leadless brass materials according to Examples 1 to 45 include copper, zinc, bismuth, selenium, and silicon. Moreover, tin, aluminum (Al), and other impurities may be included as appropriate. By adding selenium, selenium coexists with bismuth (see FIGS. 4B and 5A), and it is considered that the machinability is improved. Also, selenium coexisting with silicon is considered to be able to fill the nest and improve casting cracks.

The lead-less brass material according to the present embodiment preferably has a selenium content of 0.04 to 0.58 mass%. As shown in Comparative Example 25, when the selenium content is about 0.02% by mass, improvement in cutting workability is not observed. As shown in Examples 1 to 45, the bismuth content is preferably 0.59 to 2.44 mass%, and the silicon content is preferably 0.30 to 1.68 mass%. Thereby, corrosion resistance can be improved, maintaining cutting workability to some extent.

Further, as shown in Examples 12 to 45, when the bismuth content is 0.76% by mass or more, the machinability is further improved. As shown in Examples 1 to 43, when the bismuth content is 1.72% by mass or less, the castability is improved.

Further, as shown in Examples 1 to 12, 14 to 21, 23 to 25, and 27 to 45, the corrosion resistance is further improved when the silicon content is 0.53% by mass or more. As shown in Examples 1 to 19, 21, 22, 24 to 29, 31 to 37, 39 to 41, 44, 45, when the silicon content is 1.00% by mass or less, the machinability is further improved. improves.

Thus, in the lead-less brass material containing copper, zinc, bismuth, selenium and silicon, the selenium content is 0.04 to 0.58 mass% and the bismuth content is 0.76 to 1.72 mass%. When the silicon content is 0.53 to 1.00% by mass, cutting workability, castability and corrosion resistance can be achieved at a higher level.

Further, in a lead-less brass material containing copper, zinc, bismuth, selenium and silicon, the selenium content is 0.04 to 0.15 mass%, the bismuth content is 0.76 to 1.00 mass%, silicon By making the content of 0.53 to 1.00% by mass, it is possible to reduce material costs while at the same time achieving higher levels of cutting workability, castability, and corrosion resistance.

In addition, the lead content in the lead-less brass material according to the present embodiment is preferably less than 0.25% by mass. Thereby, it becomes easy to use for water appliances, such as a faucet metal fitting and a water pipe. The lead content is preferably less than 0.15% by weight, more preferably less than 0.10% by weight, and even more preferably less than 0.05% by weight.

A water supply device (water faucet) was manufactured by casting using a lead-less brass material containing each element at a rate as shown in each of the above examples. Specifically, in the first step, the materials were prepared so that each faucet fitting was a component of the examples shown in Table 2. Next, in the second step, molding was performed by casting. Then, in the third step, the obtained molded product was cut, and in the fourth step, the product was completed. In this way, even if a water supply device having a complicated internal shape and a non-monotonous external shape is manufactured by casting using the leadless brass material according to the present embodiment, there is no problem due to casting, and cutting is easy. You can get water supplies.

The present invention has been described with reference to the above-described embodiments and examples. However, the present invention is not limited to the above-described embodiments and examples, and the configuration of each example is appropriately set. Combinations and substitutions are also included in the present invention. Further, based on the knowledge of those skilled in the art, the combination of the embodiments and examples and the order of processing can be appropriately changed, and various modifications such as design changes can be added to the embodiments and examples. Embodiments to which such modifications are added can also be included in the scope of the present invention.

The present invention can be used for water appliances such as faucet fittings.

11 Central type, 12a, 12b restraint type, 13 recesses, 14 grooves, 16 thermal insulation, 17 grooves, 18a, 18b recesses, 19 molten metal.

Claims

A leadless brass material comprising copper, zinc, bismuth, selenium and silicon,
A lead-less brass material, wherein the selenium content is 0.04 to 0.58 mass%.
The bismuth content is 0.59 to 2.44% by mass,
2. The leadless brass material according to claim 1, wherein the silicon content is 0.30 to 1.68% by mass.
A leadless brass material comprising copper, zinc, bismuth, selenium and silicon,
The selenium content is 0.04 to 0.58% by mass,
The bismuth content is 0.76 to 1.72% by mass,
A lead-less brass material having a silicon content of 0.53 to 1.00% by mass.
A leadless brass material comprising copper, zinc, bismuth, selenium and silicon,
The selenium content is 0.04 to 0.15% by mass,
The bismuth content is 0.76 to 1.00% by mass,
A lead-less brass material having a silicon content of 0.53 to 1.00% by mass.
Lead-free brass material according to any one of claims 1 to 4, wherein the lead content is less than 0.25% by mass.
A water supply device manufactured using the lead-less brass material according to any one of claims 1 to 5.