JP2010106363A - Age precipitation type copper alloy, copper alloy material, copper alloy component and method for producing copper alloy material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper alloy which has excellent machinability and is particularly suitable for use requiring high strength or high conductivity. <P>SOLUTION: The age precipitation type copper alloy comprises, by mass, 1.5 to 7.0% Ni and 0.3 to 1.8% Si, wherein compounds having the average size of ≥1 μm and contributing its machinability are present by ≥1,000 pieces/mm<SP>2</SP>. Alternately, the copper alloy further contains at least one selected from the group consisting of Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg, V, P and Zn, by 0.05 to 2% in total, and the balance Cu with inevitable impurities, wherein metallic element-containing compounds having the average size of ≥1 μm are present by ≥1,000 pieces/mm<SP>2</SP>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to metal parts used in electronic equipment, precision machinery, automobiles, etc., particularly copper alloy parts manufactured by cutting, and further, an aging precipitation type copper alloy suitable for this copper alloy part, and this copper alloy is processed by cutting. The present invention relates to a copper alloy material formed into a shape suitable for the above and a manufacturing method thereof.

Cutting methods such as turning and drilling are methods for producing metal parts. Cutting is an effective processing method particularly for manufacturing parts having complicated shapes and parts requiring high dimensional accuracy. When performing a cutting process, the machinability often becomes a problem. The machinability includes items such as scrap disposal, tool life, cutting resistance, and cutting surface roughness, and the material has been improved to improve these.

Copper alloys are used in many metal parts for reasons such as high strength, excellent electrical conductivity and thermal conductivity, excellent corrosion resistance, and excellent color tone. A lot of processing by cutting is carried out,
For example, there are uses such as water faucets, valves, gears, ornaments, brass (Cu-Zn series), bronze (Cu-Sn series), aluminum bronze (Cu-Al series), white (Cu-Zn-Ni) In order to improve machinability, alloys containing lead are used (see Patent Documents 1 to 4). These are all applications that do not require high strength or high conductivity.

For applications requiring high strength or high conductivity, such as pin materials for coaxial connectors,
Free-cutting phosphor bronze (see Patent Document 5) obtained by adding lead to phosphor bronze or beryllium copper and free-cut beryllium copper (see Patent Document 6) are used. These are cut by a precision machine tool such as an NC lathe and used for highly reliable parts such as electronic devices.

Thus, in order to improve the machinability of a copper alloy, lead is generally added. This is because lead does not dissolve in the copper alloy, so it is finely dispersed in the material, and the cutting waste is easily divided at that portion during cutting. However, the use of lead is being restricted because it is considered to have an adverse effect on the human body and the environment, and there is an increasing demand for copper alloys that do not contain lead and have improved machinability. As a method for improving machinability without adding lead, a method of adding bismuth to brass or bronze (see Patent Documents 7 to 8) is known. In brass, the zinc concentration is increased to form a β-phase or γ-phase that is a copper-zinc compound (Patent Document 9), or silicon is added to form a κ-phase that is a copper-silicon compound ( Patent Document 10), a method for improving the machinability by causing these compounds to act as starting points for cutting waste cutting is known.

JP 60-056036 A JP 58-113336 A JP 51-101716 A Japanese Patent Laid-Open No. 01-177327 Japanese Patent Laid-Open No. 50-066423 JP 52-117244 A JP 2001-059123 A JP 2000-336442 A JP 2000-319737 A JP 2004-183056 A

However, the technique described in each patent document has the following problems. In each technique of patent documents 1-6, lead is used as an additive element for improving machinability, and there is a concern about the load to the environment. In particular, in the technique described in Patent Document 6, there is no substitute for lead as an additive element for improving the machinability of free-cutting beryllium copper, and beryllium itself is listed as one of the elements that affect the environment. In addition, there is a growing demand for a beryllium copper substitute material as well as a lead-added copper alloy substitute material. Further, in the techniques of Patent Documents 7 to 8, when bismuth is added, the machinability is improved, but cracking is likely to occur during processing, and particularly hot processing becomes difficult. That is, it is necessary to improve the hot workability. In Patent Documents 9 to 10, the formed compound is unique to the brass system.

In applications that require high strength or high conductivity, it is possible to use an alloy system (Cu-Ni-Si system: so-called Corson alloy) in which nickel and silicon are added to copper. There has not been sufficient study to improve machinability, and further studies are required to obtain a material with excellent machinability.

The present invention has been made in view of such problems, and provides a copper alloy having excellent machinability that is particularly suitable for applications requiring high strength or high conductivity without using environmentally hazardous substances. It is the purpose.

As a result of intensive studies, the present inventors have used an aging precipitation type copper alloy having a specific composition, and the presence of 1000 elements / mm ² or more of metal element-containing compounds having a size (average diameter) of 1 μm or more makes it possible to cut. It was found that a copper alloy having excellent strength and conductivity can be obtained. In order to obtain a copper alloy-metal-element-containing compound is present 1000 / mm ² or more, it is also preferable not to oxidize the molten metal at the time of formation are preferred, also dissolution of compounds that act as cooling control speed, nuclei during casting I found out.

That is, the present invention provides the following solutions.
(1) A copper alloy containing 1.5 to 7.0 mass% of Ni and 0.3 to 1.8 mass% of Si, and having an average diameter of 1 μm or more and a compound that contributes to improved machinability An age-precipitation copper alloy characterized by being 1000 / mm ² or more.
(2) Ni is contained in 1.5 to 7.0 mass%, Si is contained in 0.3 to 1.8 mass%, and Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg, V, A copper alloy containing 0.05 to 2 mass% of a total amount of at least one selected from the group of P and Zn, with the balance being Cu and inevitable impurities, with an average diameter of 1 μm or more for improved machinability An age-precipitation copper alloy characterized in that there are 1000 / mm ² or more of compounds that contribute to
(3) Ni is contained in 1.5 to 7.0 mass%, Si is contained in 0.3 to 1.8 mass%, and Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg, V, A copper alloy containing at least one selected from the group of P and Zn in a total amount of 0.05 to 2 mass%, the balance being Cu and unavoidable impurities, Co, Zr, Ti, Fe, Mn, Cr, Sn, Al
An aging precipitation type copper alloy characterized in that there are 1000 / mm ² or more of compounds that contribute to improving machinability with an average diameter of 1 μm or more, containing any of Mg, V, P, and Zn.
(4) The aging precipitation type copper alloy according to any one of (1) to (3), wherein the compound contributing to the improvement of the machinability is a metal element-containing compound.
(5) A compound that acts as a nucleus exists in the metal element-containing compound, and the compound that acts as the nucleus has a higher melting point than the metal element-containing compound.
Aging precipitation type copper alloy as described in).
(6) The aging precipitation type copper alloy according to any one of (1) to (5), wherein an average diameter of the compound contributing to the improvement of the machinability is 30 μm or less.
(7) the density of the compound that contributes to the machinability improvement, 30000 / wherein the mm ² or less, (1) to (5) or age-precipitation type copper alloy according to one of.
(8) A copper alloy material obtained by molding the aging precipitation type copper alloy according to any one of (1) to (7) into a predetermined shape, wherein the tensile strength after molding is 500 MPa or more, and the electrical conductivity is A copper alloy material characterized by being 25% IACS or more.
(9) A copper alloy part formed by cutting the copper alloy material according to (8).
(10) The method for producing a copper alloy material according to (8), wherein the melting point of the metal element-containing compound is obtained by melting the raw material of the copper alloy material and casting the copper alloy material in the step after casting. A method for producing a copper alloy material, wherein the temperature is higher than a maximum temperature.
(11) The method for producing a copper alloy material according to (10), wherein the maximum temperature is any one of a hot working temperature, an annealing temperature, an aging heat treatment temperature, or a solution temperature.
(12) The method for producing a copper alloy material according to (10) or (11), wherein a cooling rate during casting is 0.5 ° C./second or more and 100 ° C./second or less.
(13) The method for producing a copper alloy material according to (10) or (11), wherein melt casting is performed in a non-oxidizing atmosphere.
(14) A method for producing the copper alloy material according to (8) by forming the aging precipitation type copper alloy according to (5) into a predetermined shape, which is oxidized from an element constituting the metal element-containing compound. The method for producing a copper alloy material according to any one of (10) to (13), comprising a step of adding an easy element.

The aging precipitation type copper alloy of the present invention is excellent in strength and conductivity, and is excellent in machinability without using environmentally hazardous substances such as lead and beryllium. The copper alloy of the present invention is
It is suitable as a material for parts such as electronic equipment manufactured by cutting.

It is a photograph which shows the SEM image of the compound which contributes to the machinability improvement in the preferable embodiment of the aging precipitation type copper alloy of this invention.

Preferred embodiments of the aging precipitation type copper alloy and copper alloy material of the present invention will be described in detail. First, the effect of each alloy element and the range of its content will be described.
In this specification, “copper alloy” refers to a material that does not include the concept of shape, and “copper alloy material” refers to a material that includes the concept of shape. Further, in the present specification, a “metal element-containing compound” is defined, and this “metal element-containing compound” is mainly classified into 2 of “crystallized product” and “precipitate”.
Classify into types. The “crystallized product” is generated in the process of solidification of the molten metal during the casting of the copper alloy, and the “precipitate” is generated by heat treatment in the state of a solid metal. Therefore, “crystallized product” and “precipitate” are clearly distinguished.

Nickel (Ni) and silicon (Si) in a preferred embodiment of the copper alloy and copper alloy material of the present invention are formed by depositing Ni-Si precipitates in the metal matrix (matrix) by controlling the content ratio of Ni and Si. Ni ₂ Si) is formed for precipitation strengthening and added to improve the strength and conductivity of the copper alloy. Although this Ni-Si precipitate (Ni ₂ Si: precipitate for strengthening precipitation) is formally a metal element-containing compound, it does not contribute much to the improvement of machinability.

In a preferred embodiment of the copper alloy and copper alloy material of the present invention, a compound that contributes to improving the machinability is formed, which is coarser than the precipitate for precipitation strengthening described above. This compound is a metal element-containing compound, such as a crystallized product containing at least one of nickel and silicon, or a crystallized product containing at least one of nickel and silicon and other additive elements described later. These metal element-containing compounds act as starting points for cutting waste when the cutting is performed, so that the cutting waste is easily finely divided and the machinability is improved.

The content of Ni is 1.5 to 7.0 mass% (mass%), and 1.7 to 6.5 mass.
% Is preferred. If the amount of Ni is less than 1.5 mass%, the amount of precipitation hardening due to Ni—Si precipitates is small and the strength is insufficient, and the amount of coarse crystals formed is small, and the effect of improving machinability is not observed. If the amount of Ni is more than 7.0 mass%, grain boundary reaction type precipitation occurs during the heat treatment, and the amount of coarse crystallized material increases excessively, which may reduce the strength.

When the Ni content is calculated by mass% in the formation of Ni-Si precipitates (Ni ₂ Si), an amount of about 1/4 of the Ni content is required. Further, when Si is contained in the metal element-containing compound, it is preferable to add a corresponding amount of Si, and when containing Ni, it is preferable to reduce the amount of Si. From these things, in this invention, content of Si is 0.3-1.8.
It is mass%, and it is preferable that it is 0.35-1.7 mass%.

In a preferred embodiment of the copper alloy and copper alloy material of the present invention, the average diameter is 1
The metal element-containing compound having a size of μm or more needs to be 1000 / mm ² or more.
For that purpose, cobalt (Co), zirconium (Zr), titanium (Ti), iron (Fe)
, Manganese (Mn), Chromium (Cr), Tin (Sn), Aluminum (Al), Magnesium (Mg), Vanadium (V), Phosphorus (P), Zinc (Zn) It is preferable. These elements form a metal element-containing compound with Cu, Ni, Si, or with each other, and improve machinability. In this case, the metal element-containing compound is almost a crystallized product. When contained, Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg
It is preferable to contain 0.05 to 2 mass% of one or more selected from V, P and Zn in a total amount. When it is less than 0.05 mass%, the number of crystallized substances formed is small, and the machinability is not improved. On the other hand, if it is more than 2 mass%, not only is the effect of improving the machinability saturated, but also the conductivity is lowered, which is not a good idea.

Next, the definition of the size and number of the metal element-containing compound, which is a compound that contributes to improved machinability, and the formation method and characteristics will be described. The metal element-containing compound has an action of finely cutting the cutting waste generated during cutting, thereby improving the machinability. However, if the size (average diameter) is smaller than 1 μm, a great effect cannot be obtained. Moreover, even if there is a metal element-containing compound of 1 μm or more, the cutting waste is not finely divided if the number of the existing elements is small. Specifically, if the metal element-containing compound having a size of 1 μm or more (for example, a crystallized product) is not distributed at a density of 1000 pieces / mm ² or more, the cutting waste is not sufficiently divided.

The upper limit of the size of the metal element-containing compound is not particularly specified, but is preferably about 30 μm. When it exceeds 30 μm, not only the roughness of the cutting surface is lowered, but also cracking is likely to occur during cold working, and it may be difficult to process to the dimensions required by the user. The upper limit of the density of the metal element-containing compound is not particularly specified, but is desirably about 30000 pieces / mm ² . Ratio is increased occupied by 30000 / mm ² by weight, the metal-element-containing compound, the strength of the material may be reduced.

As described above, the crystallized product is a metal element-containing compound generated in the process of solidification of the molten metal in casting in the production process. In general, a crystallized substance has a weak binding force with a parent phase, and therefore acts as a starting point for breaking up debris during cutting. On the other hand, precipitates are metal element-containing compounds that are generated by heat treatment in the state of solid metal. Depending on the alloy system, the precipitates are generally smaller in size than the crystallized material and have a strong bonding force with the parent phase. It is difficult to act as a starting point. However, in the case of precipitates formed at the crystal grain boundaries, an increase in size may act as a starting point for cutting waste separation. In addition, as a metal element-containing compound, there is a compound that remains undissolved at the time of dissolution (undissolved compound), but this has a weak binding force with the parent phase and acts as a starting point for cutting waste fragmentation. Similar to the crystallized product, it can be used as a means for improving machinability.
That is, the crystallized product, the precipitate, and the undissolved compound each have a size (average diameter) of 1 μm or more and a metal element-containing compound in the aging precipitation type copper alloy in order to have a function of finely cutting the cutting waste. The distribution density is required to be 1000 / mm ² or more.

Furthermore, the melting point of the metal element-containing compound is preferably higher than the maximum temperature of the copper alloy material in the step after melting and casting the raw material of the copper alloy material. This maximum temperature is generally one of a hot working temperature, an annealing temperature, an aging heat treatment temperature, or a solution temperature before aging precipitation when the material is hot worked. This is because the metal element-containing compound, which is a compound that contributes to improved machinability in each heating step, does not cause melting or disappearance.

In addition, among the metal element-containing compounds that are compounds that contribute to improvement in machinability, the size and distribution of crystallized substances vary depending on the cooling rate during casting. When the cooling rate is slow, the crystallized material becomes coarse and sufficient cutting chip separation may not be obtained. Therefore, cooling is preferably performed at 0.5 ° C./second or more, more preferably 1 ° C./second or more. The copper alloy of the present invention is obtained. Further, if the cooling rate is too fast, the crystallized product becomes too fine and the cutting waste is inferior, and therefore it is preferably 100 ° C./second or less. As a casting method for increasing the cooling rate, for example, there is a twin roll casting method. In this method, the material is rapidly solidified by pouring between two pairs of rotating rolls.

As another method for finely forming a crystallized product as a metal element-containing compound that is a compound that contributes to improved machinability, there is a method of forming a crystallized product around a compound having a composition different from that of the crystallized product. is there. This is a method in which a compound having a composition different from that of the crystallized substance or a raw material thereof is charged or formed in the molten metal before the target crystallized substance is formed, and the crystallized substance is formed using the compound as a nucleus. is there.

A compound having a composition different from that of the crystallized substance and acting as a nucleus for crystallized substance formation (hereinafter, simply referred to as “compound acting as a nucleus”) needs to have a higher melting point than the target crystallized substance. Specifically, non-metal element-containing compounds such as carbides, sulfides, borides, oxides, and nitrides are effective. These are the ones in which the nonmetallic element-containing compound is directly put into the molten metal as a powder, or Ni,
It is formed in the melt as a compound that acts as a nucleus by bonding with an alloy component such as Si or a newly added metal element in the melt. Carbon in forming compounds that act as nuclei,
As a method of adding a nonmetallic element such as sulfur or boron into a copper alloy, a method of adding it as it is (for example, immersing a carbon rod) or a method of adding it in the state of a compound with another element (for example, copper- Boron master alloy is used as a raw material). Note that the size (average diameter) of the compound acting as a nucleus is usually smaller than 1 μm, and the compound acting as a nucleus itself hardly contributes directly to the improvement of machinability.

When many compounds that act as nuclei are formed in the molten metal, crystallized substances are formed around the nuclei, and if the number of nuclei is large, the number of crystallized substances is increased, and the function of finely dividing the cutting waste is achieved. It has the size and density it has. This method is particularly effective when the cooling rate is low, and when the cooling rate is high, even if there is no compound that acts as a nucleus, the crystallized product has a size and density that has the effect of finely cutting the cutting waste. There is no need to form a compound that acts as a nucleus.

In a preferred embodiment of the copper alloy and copper alloy material of the present invention, the additive element for forming a compound (metal element-containing compound) that contributes to improvement of machinability includes an element that is easily oxidized,
For example, Si, Zr, Ti, Al, Mg, etc. are included. When these oxidizable elements are used, it is preferable to prevent oxidation by covering a melting furnace, a molten metal path, a mold and the like at the time of melting and casting, and making an inert gas atmosphere such as argon and nitrogen. By this method, the loss of the additive element is reduced, and a crystallized product having a size and density having an action of finely cutting the cutting waste can be obtained.

As another method for preventing oxidation of the additive element for forming a compound (metal element-containing compound) that contributes to improved machinability, the additive element for forming a compound (metal element-containing compound) that contributes to improved machinability There is a method of adding an element that is easily oxidized. For example, Cu-Ni-S
The case where Zr, Fe, Ti, and Sn, which are additive elements for forming a compound (metal element-containing compound) that contributes to the improvement of machinability, based on the i system, will be described. When these elements (Zr, Fe, Ti, and Sn) are dissolved, if Al, Mg, Ca, etc., which are more easily oxidized than these elements, are added, Al, Mg, Ca are oxidized.
The additive element for forming the compound (metal element-containing compound) that contributes to improved machinability is hardly oxidized, and the target compound (metal element-containing compound) is easily obtained. Note that the ease with which an element is oxidized is determined by the standard free energy of formation of the oxide, and it can be said that the smaller the energy, the more stable the oxide (that is, the more easily oxidized). The standard generation energy of oxide is, for example, “Revised 4th edition Metal Data Book edited by the Japan Institute of Metals”
"Issued in February 2004".

Next, the mechanical properties of the copper alloy material in a preferred embodiment of the present invention will be described.
The copper alloy in a preferred embodiment of the present invention aims to replace lead-containing phosphor bronze or beryllium copper, that is, a copper alloy containing environmentally hazardous substances, and requires the same strength as these alloys. . Therefore, the strength and conductivity that do not cause a problem in practice are required to have a tensile strength of 500 MPa or more and a conductivity of 25% IACS or more. The copper alloy of the present invention is an aging precipitation type, and the strength and conductivity are improved by forming Ni ₂ Si as described above. For that purpose, Ni is 1.5 to 7.0 mass%, Si is added. 0.3 to 1.8 mass%
It is necessary to contain. Moreover, the solution heat treatment temperature in a manufacturing process is 800-950.
The range of ° C is preferred, and the aging heat treatment temperature is preferably in the range of 350 to 600 ° C.

In this invention, there is no restriction | limiting in particular in the manufacturing method of copper alloy material. Since the copper alloy in the preferred embodiment of the present invention is an aging precipitation type copper alloy, an aging heat treatment step is essential at least after the melt casting step of the copper alloy raw material, but a hot working step, an annealing step, a solution treatment The heat treatment step is performed as necessary. For example, for hot working processes, billet hot extrusion,
The copper alloy material of the present invention can be produced by any of the production methods such as hot forging of an ingot or continuous casting. Moreover, there is no restriction | limiting in particular in the shape of a product, It is preferable to set it as the shape which is easy to obtain the copper alloy component which is a last form by the cutting process which is a post process. That is, as a copper alloy material of a predetermined shape such as wire, bar, strip, plate, pipe depending on the use of copper alloy parts,
Use it properly. For example, when the copper alloy part in the final form is a screw, the shape of the copper alloy material is preferably a round bar.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

(Test Example 1)
A copper alloy having the composition shown in Table 1 is melted in a high-frequency melting furnace, and the cooling rate is 5 to 10
Each billet was cast at ° C / second. In addition, a cover such as a lid was covered to prevent oxidation, and nitrogen gas was allowed to flow into the melting furnace, the flow of molten metal to the mold, and the portion where the molten metal of the mold was in contact with the atmosphere. The billet was hot extruded at 900 ° C. and immediately quenched in water to obtain a round bar. Next, the round bar is drawn out in a cold state to produce a round bar having a diameter of 10 mm.
Time aging heat treatment was performed.

For each round bar thus obtained, [1] tensile strength, [2] conductivity, [3]
The machinability was examined by the following method. The measurement method for each evaluation item is as follows.
[1] Tensile strength Three were measured according to JIS Z 2241 and the average value (MPa) was shown.
[2] Conductivity Using a four-terminal method, two samples were measured for each sample in a thermostatic chamber controlled at 20 ° C. (± 1 ° C.), and the average value (% IACS) was shown.
[3] Cutting performance A cutting experiment was performed using a general-purpose lathe, and the form of the cutting waste was observed. The cutting waste was divided into 10 mm or less, and the cutting waste was divided, but the length of 10 mm or more was acceptable, and the cutting scrap connected in a spiral shape was defective. It is good and good that there is no practical problem. The cutting conditions were a cutting speed of 30 m / min, a feed speed of 0.1 mm / rev, and a cutting allowance of 0.2 mm. The tool was made of cemented carbide and no cutting oil was used.

In addition, the size and number of the metal element-containing compound (simply referred to as “compound” in the table) that contributes to improved machinability can be measured using a scanning electron microscope (SEM) at any three locations on the cross section of the billet. Each was obtained by observing the structure for three visual fields. The size (average diameter) is
The size of 10 compounds per field of view was measured and averaged. For the number, the number of compounds found in one visual field was counted and the average was taken. The number was converted to the number per 1 mm ² and rounded to the nearest tenth. Components of the metal element-containing compound were investigated using an energy dispersive X-ray fluorescence analyzer (EDX) attached to the SEM.

The results are shown in Table 2. Alloy No. 1 to 22 are examples of the present invention, alloy no. Nos. 23 to 28 are comparative examples in which the components are out of the scope of the present invention, alloy nos. 29 and 30 are conventional free-cutting phosphor bronze and free-cutting beryllium copper.

Alloy No. The inventive examples 1 to 22 all have a tensile strength of 500 MPa or more and an electrical conductivity of 25%.
I am more than IACS. Moreover, good or good is obtained in all of the cutting property of the cutting waste.

On the other hand, the alloy no. In Nos. 23 and 24, the main components Ni and Si are outside the scope of the present invention, so that the tensile strength or the electrical conductivity is not satisfactory. Alloy No. 25 and 2
In No. 6, since the content of additive elements other than Ni and Si is less than the range of the present invention, the density of the metal element-containing compound is less than 1000 / mm ² of the present invention, and the machinability is inferior. Also,
Alloy No. 27 and no. No. 28 is inferior in conductivity because the content of additive elements other than Ni and Si is larger than the range of the present invention.

(Test Example 2)
Alloy No. 1 in Table 1 5 and no. 17 is a small experimental mold (25 mm × 25
mm × 300 mm) was used to change the cooling rate during casting to produce small ingots having various metal element-containing compound sizes. As in Test Example 1, nitrogen gas was introduced into a portion where the molten metal such as a melting furnace and a slag contacted the atmosphere with a lid for preventing oxidation. The resulting ingot is 9
Hot forging was performed at 00 ° C., and directly quenched in water to obtain a round bar. Next, the round bar was drawn out cold to produce a round bar having a diameter of 10 mm, and further subjected to aging heat treatment at 450 ° C. for 2 hours.
For each of the round bars thus obtained, [1] tensile strength, [2] conductivity, [3] machinability are examined by the above method, and the size and number of the metal element-containing compound are determined by the above method. Asked. The results are shown in Table 3.

As shown in Table 3, sample no. In B, C, F, and G, the size and distribution density of the metal element-containing compound were within the scope of the present invention, and the machinability of the manufactured round bar was excellent. Sample No. In A and E, the cooling rate was high, and the size of the metal element-containing compound was 1 μm or less, and the machinability of the manufactured round bar was inferior. Sample No. In D and H, the cooling rate was slow, the density of the metal element-containing compound was small, and the machinability of the manufactured round bar was inferior.

(Test Example 3)
In Test Example 2, because the cooling rate during casting was slow and the distribution density of the metal element-containing compound was reduced, Alloy No. 5 and no. For 17 samples D and H, in order to form a compound (non-metal element-containing compound) that acts as a nucleus of a compound (metal element-containing compound) that contributes to machinability, (a) a carbon rod is placed in the crucible when dissolved. Immersion for 30 minutes, (b) Use copper-boron mother alloy as raw material, (c) 0.1% aluminum
The additional steps of addition and addition were performed, respectively. No. 5 has a cooling rate of 0.2 ° C./second.
No. 17 was cooled at a cooling rate of 0.1 ° C./second to produce a small ingot. Alloy N
o. About 17, the additional process (a) was performed and casting was performed by changing the cooling rate. The obtained ingot was hot forged at 900 ° C. and directly quenched in water to obtain a round bar. Next, the round bar was drawn out cold to produce a round bar having a diameter of 10 mm, and further subjected to aging heat treatment at 450 ° C. for 2 hours. For each round bar thus obtained, [1] tensile strength, [2] conductivity, [3] machinability were examined by the method of Test Example 1, and the size and number of metal element-containing compounds were determined. Obtained by the method of Moreover, the component investigation was conducted by EDX about the nonmetallic element containing compound seen inside the metallic element containing compound at the time of SEM observation. The results are shown in Table 4.

Comparison of Samples D1 to D3 in Table 4 with Sample D in Table 3 and Samples H1 to H1 in Table 4
From the comparison between H6 and Sample H in Table 3, the size and density of the metal element-containing compound can be obtained by performing additional steps (a), (b), and (c) even when the cooling rate during casting is slow. It is within the scope of the invention, and it can be seen that the machinability of the manufactured round bar is improved. When the cooling rate is changed by performing the additional step (a), when the cooling rate is increased, the compound has a size and density having an action of finely dividing the cutting waste, but samples E, F, and G in Table 3 are used. From comparison with
When the cooling rate is high, the effect of the step (a) is hardly observed. Additional step (a)
, (B), (c), non-metal element-containing compounds such as carbides and borides acting as nuclei are observed inside the compounds.

In FIG. The SEM image of the compound which contributes to the machinability improvement of the ingot of the sample H1 obtained by adding a process (a) to the sample H of 17 is shown. In FIG. 1, 1 is a metal element-containing compound (compound that contributes to improved machinability), 2 is a non-metal element-containing compound (a compound that acts as a nucleus), and is seen near the center of the metal element-containing compound 1 in FIG. The resulting granular material is a non-metallic element-containing compound 2 that acts as a nucleus of the metallic element-containing compound 1, and is specifically Ti carbide (TiC). The size (average diameter) of the compound was about 0.6 μm.

(Test Example 4)
Alloy No. 1 in Test Example 1 5 and no. For No. 17, a billet was produced by melting and casting without inflow of nitrogen gas for preventing oxidation, and a round bar having a diameter of 10 mm was produced and evaluated in the same process as in Test Example 1. The results are shown in Table 5.

As shown in Table 5, Z was added as an additive element because no nitrogen gas was introduced during melting and casting.
r and Ti were oxidized, and the density of the compound containing Zr and Ti that contributed to the improvement of machinability was significantly reduced. As a result, the machinability of the manufactured round bar has deteriorated.

(Test Example 5)
Alloy No. 1 in Test Example 1 5 and no. For No. 17, a billet added with 0.005 mass% Mg and a billet containing no Mg as an easily oxidizable element without inflow of oxidation-preventing nitrogen gas were prepared. Bars were manufactured and evaluated. The results are shown in Table 6.

As shown in Table 6, the billet to which Mg was added had an appropriate compound density, and the round bar produced from this billet had good machinability, and the round produced from the billet to which no Mg was added. Improved machinability compared to the bar. This is because Mg, which is an element that is more easily oxidized than these elements, is added at the time of dissolution of Si, Zr, Fe, and Ti, which are additive elements for forming a compound (metal element-containing compound) that contributes to improved machinability. As a result, Mg is preferentially oxidized. As a result, it is considered that the additive element for forming the compound (metal element-containing compound) contributing to the improvement of machinability was hardly oxidized.

1 Metal element-containing compounds (compounds that contribute to improved machinability)
2 Nonmetallic element-containing compounds (compounds that act as nuclei)

Claims (14)

It is a copper alloy containing 1.5 to 7.0 mass% of Ni and 0.3 to 1.8 mass% of Si, and has 1000 compounds / contributing to improving machinability with an average diameter of 1 μm or more. m
An aging precipitation type copper alloy characterized by existing in m ² or more. Containing 1.5 to 7.0 mass% of Ni, 0.3 to 1.8 mass% of Si, and Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg, V, P, Zn This is a copper alloy containing 0.05 to 2 mass% in total of at least one selected from the group consisting of Cu and the balance consisting of Cu and inevitable impurities, and contributes to improved machinability with an average diameter of 1 μm or more. An aging precipitation type copper alloy characterized by the presence of 1000 compounds / mm ² or more. Containing 1.5 to 7.0 mass% of Ni, 0.3 to 1.8 mass% of Si, and Co, Zr, Ti, Fe, Mn, Cr, Sn, Al, Mg, V, P, Zn A copper alloy containing 0.05 to 2 mass% in total of at least one selected from the group consisting of Cu and the remainder consisting of Cu and inevitable impurities, Co, Zr, Ti, Fe, Mn, Cr, Sn, Al , M
An aging precipitation type copper alloy characterized in that there are 1000 / mm ² or more of compounds that contribute to improving machinability with an average diameter of 1 μm or more, containing any of g, V, P, and Zn. The aging precipitation type copper alloy according to any one of claims 1 to 3, wherein the compound contributing to the improvement of the machinability is a metal element-containing compound. The compound acting as a nucleus exists inside the metal element-containing compound, and the compound acting as the nucleus has a higher melting point than the metal element-containing compound.
Aging precipitation type copper alloy as described in 1. The average diameter of the compound that contributes to the improvement of machinability is 30 μm or less,
The aging precipitation type copper alloy of any one of Claims 1-5. The aging precipitation type copper alloy according to any one of claims 1 to 5, wherein the density of the compound contributing to the improvement of the machinability is 30000 pieces / mm ² or less. A copper alloy material in which the aging precipitation type copper alloy according to any one of claims 1 to 7 is molded into a predetermined shape, wherein the tensile strength after molding is 500 MPa or more, and the conductivity is 25% IACS. A copper alloy material characterized by the above.   A copper alloy part formed by cutting the copper alloy material according to claim 8. It is a method of manufacturing the copper alloy material according to claim 8, wherein the melting point of the metal element-containing compound is higher than the maximum temperature of the copper alloy material in the step after melting and casting the raw material of the copper alloy material. A method for producing a copper alloy material, characterized by being at a high temperature. The method for producing a copper alloy material according to claim 10, wherein the maximum temperature is any one of a hot working temperature, an annealing temperature, an aging heat treatment temperature, or a solution temperature. The method for producing a copper alloy material according to claim 10 or 11, wherein a cooling rate during casting is 0.5 ° C / second or more and 100 ° C / second or less. The method for producing a copper alloy material according to claim 10 or 11, wherein melt casting is performed in a non-oxidizing atmosphere. The method for producing a copper alloy material according to claim 8, wherein the aging precipitation type copper alloy according to claim 5 is formed into a predetermined shape, wherein the element is more easily oxidized than an element constituting the metal element-containing compound. The method for producing a copper alloy material according to any one of claims 10 to 13, further comprising a step of adding.

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