CN113355558A

CN113355558A - Lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment

Info

Publication number: CN113355558A
Application number: CN202110641561.XA
Authority: CN
Inventors: 冯斌; 李威; 张毅; 黄敏; 章建炜; 黄剑杰
Original assignee: Ningbo Xingaoda Advanced Metallic Materials Co Ltd
Current assignee: Ningbo Xingaoda Advanced Metallic Materials Co Ltd
Priority date: 2021-06-09
Filing date: 2021-06-09
Publication date: 2021-09-07

Abstract

The invention relates to the technical field of copper alloy materials, in particular to a lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment, which comprises the following components in percentage by mass: 55 to 68% of Cu, 0.1 to 0.3% of Sn, 0.4 to 1.0% of Bi, 0.01 to 0.1% of B, 0.02 to 0.15% of Se, 0.06 to 0.08% of P, 0.1 to 0.5% of Mn, 0.1 to 0.5% of Al, 0.05 to 0.5% of Mg, and the balance of Zn and inevitable impurities. The lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment disclosed by the invention is extremely low in lead content, is environment-friendly and harmless when being contacted with drinking water, and has good oxidation resistance, corrosion resistance and machining performance of a cutting machine.

Description

Lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment

Technical Field

The invention relates to the technical field of copper alloy materials, in particular to a lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment.

Background

With the development of living standard, the quality of drinking water is more and more concerned by people. The harmful contamination of drinking water by components contained in materials used in drinking water delivery equipment is a considerable problem. The copper alloy is an alloy material formed by adding one or more elements into pure copper serving as a matrix. Because of the excellent properties of copper such as cutting, stretching and the like, the copper alloy is widely applied to various industries, and is particularly suitable for producing valves, pipe fittings and various spare and accessory parts thereof in drinking water systems. The brass alloy has the characteristics of special antibacterial and bactericidal performance, good corrosion resistance, good tensile cutting performance, renewable recovery and the like, and is widely applied to water delivery and distribution equipment such as taps, valves, pipe connectors and the like, particularly, the lead brass has the widest range due to the excellent free-cutting property, but in the using process, metal lead is easily dissolved out from a brass matrix and enters a water body, so that the lead content in drinking water exceeds the standard. For safety and health reasons, drinking water delivery equipment must use lead-free copper alloy materials, the content of Pb element in the alloy materials must be less than the national regulation standard.

Disclosure of Invention

The invention aims to overcome the defects of the existing copper alloy material for the drinking water conveying equipment, and provides a lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment, which has extremely low lead content, is environment-friendly and harmless when being contacted with drinking water, and has good oxidation resistance, corrosion resistance and machining performance of a cutting machine. In order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment comprises the following components in percentage by mass: 55 to 68% of Cu, 0.1 to 0.3% of Sn, 0.4 to 1.0% of Bi, 0.01 to 0.1% of B, 0.02 to 0.15% of Se, 0.06 to 0.08% of P, 0.1 to 0.5% of Mn, 0.1 to 0.5% of Al, 0.05 to 0.5% of Mg, and the balance of Zn and inevitable impurities.

Further, the composite material comprises the following components in percentage by mass: 58 to 65% of Cu, 0.1 to 0.2% of Sn, 0.6 to 0.8% of Bi, 0.01 to 0.05% of B, 0.05 to 0.1% of Se, 0.06 to 0.08% of P, 0.2 to 0.35% of Mn, 0.1 to 0.3% of Al, 0.1 to 0.2% of Mg, and the balance of Zn and inevitable impurities.

Further, the composite material comprises the following components in percentage by mass: 58 to 60% of Cu, 0.1 to 0.12% of Sn, 0.6 to 0.8% of Bi, 0.01 to 0.05% of B, 0.05 to 0.08% of Se, 0.06 to 0.08% of P, 0.25 to 0.3% of Mn, 0.1 to 0.13% of Al, 0.1 to 0.13% of Mg, and the balance of Zn and inevitable impurities.

Further, Sn and Bi in the alloy material are added as raw materials in the form of elemental metals, respectively.

Further, the B is added as a raw material in the form of a boron-copper intermediate alloy, and the content of the B in the boron-copper intermediate alloy is 10%.

Further, the P is added in the form of a phosphorus-copper intermediate alloy as a raw material, and the content of the P in the phosphorus-copper intermediate alloy is 13%.

Further, the total amount of impurities is not more than 0.12%.

Further, the mass percent content of lead in the alloy material is less than 0.005%.

The reason why the types and the addition amounts of metals in the lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment are limited is that:

bismuth: the cutting performance of the alloy material can be improved by adding bismuth into the alloy material, the bismuth and copper generate eutectic at 250 ℃, when the content of bismuth is within 1-2%, the bismuth and the bismuth are uniformly distributed in a dotted manner in an (alpha + beta) phase, cutting foam is not easy to break, so that copper chips are in a slender spiral shape, and the copper chips are in large-area contact with a cutter for a long time, so that the cutting resistance is high, the cutter is easy to generate heat, and the color of the copper chips is dark yellow. When the bismuth content in the copper alloy is lower than 0.4%, the cutting performance of the material is poor, and when the bismuth content is 0.4-1.0%, the copper scraps are fine and needle-shaped, the cutting performance of the loose material of the copper scraps is improved, the brittleness of the material is reduced, and therefore the bismuth content in the alloy material is selected to be 0.4-1.0%.

Tin: the tin of the alloy material can be slightly fused into an alpha phase and an (alpha + beta) phase of the material, so that dezincification is inhibited, the corrosion resistance of the material is improved, the wear resistance of the material can be improved, and the preferable range of the tin content is 0.1-0.3%.

B, boron copper alloy: the addition of trace boron can obviously refine the crystal grains of the copper alloy, obviously improve the mechanical strength, the corrosion resistance and the erosion resistance of copper, and have better dezincification resistance when the boron is used together with tin and aluminum. When the boron content is too high, boron precipitates from the copper alloy in the form of boride to reduce the plasticity of the material, and therefore, the boron content is preferably 0.01 to 0.1%.

Selenium: the selenium is added into the alloy material, so that the mechanical property of the material can be improved, the structure of the material is more compact, the material can be cut at high speed, and the surface of a processed part is smoother, therefore, the content of the selenium is preferably 0.02-0.15%.

Manganese: the manganese is added into the copper alloy material to play a role in deoxidation and degassing and improvement of the mechanical strength of the alloy, and the preferable content range is 0.1-0.5%.

Magnesium: the addition of magnesium to the alloy material can improve the corrosion resistance and hot workability of the material, and spheroidize the matrix to improve the cutting performance of the alloy. The preferable range of the Mg content is 0.05-0.5%.

Aluminum: the corrosion resistance and the hot workability of the alloy can be improved by adding aluminum into the alloy material. For the preferred scheme, the content of aluminum is lower than 0.1%, and the effect of improving the corrosion resistance of the alloy material is not obvious; the aluminum content is higher than 0.5%, and a 'die sticking' phenomenon is easily generated in the hot working process, so that the preferred range of the aluminum content is 0.1-0.5%.

Copper phosphorus alloy: the addition of trace phosphorus can improve the fluidity of copper and has the effect of deoxidation, and phosphorus is mainly (alpha + Cu) in copper₃P) in the form of a eutectic, Cu₃The P compound has high hardness, can obviously improve the mechanical property of the alloy material, and has no obvious effect on the fluidity and deoxidation of the material when the phosphorus content is less than 0.04 percent, and has no obvious effect on the improvement of the cutting property of the material when the phosphorus content exceeds 0.1 percent, so the phosphorus content is preferably in the range of 0.06-0.08 percent.

Copper: the higher the copper content in the alloy material is, the more alpha phase is, the better the corrosion resistance and plasticity of the material is, but the corresponding cost is increased, and the cutting processing of the material is deteriorated; if the copper content is too low, the plasticity of the alloy material becomes poor.

Compared with the conventional lead brass material, the invention has the following beneficial effects:

the lead-free environment-friendly free-cutting copper alloy material provided by the invention is suitable for drinking water conveying equipment, is environment-friendly and safe, has extremely low lead content, and has good cutting processing performance, oxidation resistance and corrosion resistance. According to the invention, the addition amount of each metal element in the alloy material is adjusted to obtain the optimal accumulation effect, and the elements are mutually synergistic to ensure that the alloy material has excellent cutting performance and oxidation and corrosion resistance. According to the invention, 0.4-1.0% of bismuth and copper are added into the alloy material to generate eutectic, so that the cutting performance of the material is obviously improved; the trace phosphorus element is added in the form of phosphorus-copper alloy, so that the mechanical property and the cutting processability of the alloy material can be improved; a small amount of tin is added into the alloy material, so that the wear resistance and the corrosion resistance of the material can be improved; the grain fineness of the copper alloy is reduced by adding elements such as boron, selenium and manganese, the corrosion resistance and the mechanical strength of the alloy material are improved, and the phosphorus plays a role in improving dezincification corrosion and machinability in brass.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description, which should be understood that the following examples are only illustrative of the preferred embodiments of the present invention, show and describe the basic principles, main features and advantages of the present invention, and are only illustrative and explanatory of the present invention, but not restrictive thereof.

The preparation method of the lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment provided by the embodiments of the invention is a conventional production process of copper alloy in the industry, and the general flow is as follows:

batching → power frequency induction furnace smelting (alloying treatment, charcoal coverage protection) → full-continuous casting of an ingot with a diameter of 103mm (the smelting temperature is 1100 ℃ -1300 ℃, degassing during pouring) → 1250-ton reverse extruder 660 ℃ -680 ℃ extrusion → 23mm → 19mm → 14mm, and the final content of each component falls into the range of the distribution content; wherein Sn used in the burdening process is a pure tin ingot, and Bi is a pure bismuth ingot; p is added in the form of copper-phosphorus intermediate alloy, B is added in the form of boron-copper intermediate alloy, and the final content of each component falls into the distribution content range.

The lead brass material of the comparative example was also processed under the same process conditions.

The specific component contents of the lead-free environment-friendly free-cutting copper alloy materials of examples 1 to 4 of the present invention and the lead brass materials of comparative examples 1 to 2 are shown in table 1.

TABLE 1 compositions (wt%) of alloy materials in examples 1 to 4 and comparative examples 1 to 2

Mechanical property tests are carried out on the alloy materials in examples 1-4 and comparative examples 1-2 according to the national standard GB/T228.1-2010 respectively, and the results are shown in Table 2. The cutting performance evaluation method in table 2 is generally to fix the cutting process parameters and measure the cutting force to compare with the free-cutting lead brass HPb63-3 to obtain the relative cutting rate. However, in actual production, the "good" or "poor" of the machinability of the material is often determined according to the size of the cutting shape, the smoothness of chip removal, and the degree of tool wear. The invention adopts a chip form test method, the rotating speed of a main shaft is 1000rpm/min, the feed amount is 0.16mm/rer, and the cutting depth is 1 mm. Wherein "excellent" means good machinability, "good" means good machinability, and "poor" means poor machinability.

TABLE 2 comparison of alloy Material Properties in examples 1-4 and comparative examples 1-2

Through various test data, compared with conventional lead brass materials HPb58-3 and HPb63-3, the lead-free environment-friendly free-cutting copper alloy material provided by the invention has good cutting performance and corrosion resistance, and the machinability is equivalent to that of a lead brass material HPb 63-3.

Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that various changes, modifications and substitutions can be made without departing from the spirit and scope of the invention as defined by the appended claims. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment is characterized by comprising the following components in percentage by mass: 55 to 68% of Cu, 0.1 to 0.3% of Sn, 0.4 to 1.0% of Bi, 0.01 to 0.1% of B, 0.02 to 0.15% of Se, 0.06 to 0.08% of P, 0.1 to 0.5% of Mn, 0.1 to 0.5% of Al, 0.05 to 0.5% of Mg, and the balance of Zn and inevitable impurities.

2. The lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment as claimed in claim 1, which is characterized by comprising the following components in percentage by mass: 58 to 65% of Cu, 0.1 to 0.2% of Sn, 0.6 to 0.8% of Bi, 0.01 to 0.05% of B, 0.05 to 0.1% of Se, 0.06 to 0.08% of P, 0.2 to 0.35% of Mn, 0.1 to 0.3% of Al, 0.1 to 0.2% of Mg, and the balance of Zn and inevitable impurities.

3. The lead-free environment-friendly free-cutting copper alloy material for the drinking water conveying equipment as claimed in claim 1, which is characterized by comprising the following components in percentage by mass: 58 to 60% of Cu, 0.1 to 0.12% of Sn, 0.6 to 0.8% of Bi, 0.01 to 0.05% of B, 0.05 to 0.08% of Se, 0.06 to 0.08% of P, 0.25 to 0.3% of Mn, 0.1 to 0.13% of Al, 0.1 to 0.13% of Mg, and the balance of Zn and inevitable impurities.

4. The lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment as claimed in claim 1, wherein Sn and Bi in the alloy material are respectively added as raw materials in the form of elemental metals.

5. The lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment as claimed in claim 1, wherein the B is added as a raw material in the form of boron-copper intermediate alloy, and the content of B in the boron-copper intermediate alloy is 10%.

6. The lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment as claimed in claim 1, wherein P is added as a raw material in the form of phosphorus-copper master alloy, and the content of P in the phosphorus-copper master alloy is 13%.

7. The lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment as claimed in claim 1, wherein the total amount of impurities is not more than 0.12%.

8. The lead-free environment-friendly free-cutting copper alloy material for drinking water conveying equipment as claimed in claim 1, wherein the lead content in the alloy material is less than 0.005% by mass.