JP6742278B2 - Lead-free free-cutting phosphor bronze rod wire and manufacturing method of lead-free free-cutting phosphor bronze rod wire - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lead-free free-cutting phosphor bronze rod wire and a method for producing a lead-free free-cutting phosphor bronze rod wire that achieves high strength and is excellent in machinability.

Phosphor bronze is a Cu (copper)-Sn (tin)-P (phosphorus)-based alloy, and various characteristics are produced depending on the content of Sn. Phosphor bronze is tough, has excellent corrosion resistance, wear resistance, and solderability, and is suitable for a wide range of applications.

Free-cutting phosphor bronze is an alloy in which the machinability of phosphor bronze is improved by adding Pb (lead) to phosphor bronze, and is used for machine screws, bearings, bushes, bolts, nuts, ballpoint pen parts and the like.

Since Pb is a specific harmful substance that may violate the central nervous system of humans, the smaller the content of Pb, the more desirable.

Since free-cutting phosphor bronze improves the machinability of phosphor bronze by adding Pb to phosphor bronze, if the content of Pb decreases, the machinability naturally deteriorates. From the viewpoint of performing precision cutting, Pb is considered to be required at least 3.5% by weight.

The European Union Directive (RoHS Directive) on the restriction of the use of certain hazardous substances in electronic and electrical equipment states that electronic and electrical equipment containing Pb in excess of 1000 ppm cannot be put on the market in the European Union. However, copper alloys are exempted up to 4% by weight because there is no suitable alternative.

However, there is a possibility that the exemption will be abolished in the near future, so the development of a substitute material in which the Pb content does not exceed 1000 ppm (0.1% by weight) is an urgent issue.

As a lead-free copper alloy, in patent document 1, Sn contains 0.5-11.0 mass%, P contains 0.03-0.35 mass%, S contains 0.02-1.0 mass%, and the balance is Cu. And a copper alloy wrought material having a component composition consisting of unavoidable impurities (for example, refer to paragraph (0030) of the present invention, Example 8 of the present invention).

In addition, as a lead-free copper alloy for castings, Patent Document 2 describes a copper alloy containing Sn, S (sulfur), Fe (iron), and P in addition to Cu, and Patent Document 3 describes a copper alloy including Cu. , Sn, Zn (zinc), Ni (nickel), S, P containing copper alloys are described.

Japanese Patent No. 5916464 Japanese Patent No. 4658269 Japanese Patent No. 5335558

However, the copper alloy wrought material disclosed in Patent Document 1 has a problem that the strength (for example, bending strength, header workability, wear resistance, etc.) required for parts using phosphor bronze cannot be obtained. There is.

The copper alloys disclosed in Patent Documents 2 and 3 are castings. Castings are not applicable to wrought materials because they have significantly different functions and uses from wrought materials. Further, Patent Documents 2 and 3 do not disclose a technique related to cold working or the like for obtaining a wrought material, and do not even suggest wrought the obtained copper alloy.

In order to improve machinability, Bi (bismuth) is also added in place of Pb, but it is easily cracked during expansion and plastic working such as cold rolling and cold drawing cannot be performed, so it is desirable. There is a problem that it can not be processed into a rod wire.

The purpose of the present invention is to obtain the high strength required for parts using phosphor bronze, also excellent in machinability, the cutting dust is not connected and fine, and sufficient precision machining is also possible, (EN) Provided are a lead-free free-cutting phosphor bronze rod wire and a method for manufacturing a lead-free free-cutting phosphor bronze rod wire.

MEANS TO SOLVE THE PROBLEM As a result of earnestly studying, in order to solve the said subject, the inventor of this invention Sn 1.5-7.0 weight%, Ni 0.5-7.0 weight%, S 0.02. Found to achieve the above-mentioned object by a lead-free free-cutting phosphor bronze rod wire or the like containing .about.0.6% by weight, 0.01 to 0.35% by weight of P, and the balance of Cu and unavoidable impurities. The present invention has been completed.

That is, the first lead-free free-cutting phosphor bronze rod wire of the present invention comprises Sn in an amount of 1.5 to 7.0% by weight, Ni in an amount of 0.5 to 7.0% by weight, and S in an amount of 0.02 to 0.6% by weight. % Lead , 0.01 to 0.35% by weight of P, the balance being Cu and unavoidable impurities and lead-free free-cutting phosphor bronze rod wire having a Rockwell hardness (HRB) of 74 or more. Is characterized by.

The second lead-free free-cutting phosphor bronze rod wire according to the present invention contains Sn in an amount of 1.5 to 7.0% by weight, Ni in an amount of 0.5 to 7.0% by weight, and S in an amount of 0.02 to 0.6% by weight. % Lead , 0.9% by weight or less of Fe (not including 0% by weight), 0.01 to 0.35% by weight of P, and the balance of Cu and inevitable impurities are lead-free free-cutting phosphor bronze rods. A wire rod having a Rockwell hardness (HRB) of 74 or more .

In the lead-free free-cutting phosphor bronze rod wire of the present invention, the content of Sn and the content of Ni satisfy the relationship of 2.5%≦1.3Sn+Ni≦9.2% in weight %. Further, it is also possible to adopt a constitution in which the relationship of 3.5%≦1.3Sn+Ni≦8.5% is satisfied in weight %.

In the lead-free free-cutting phosphor bronze rod wire of the present invention, it is possible to adopt a configuration in which Sn is 3.5 to 6.5% by weight.

The first method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention is 1.5 to 7.0 wt% Sn, 0.5 to 7.0 wt% Ni, and 0.02 to 0. A method for producing a lead-free free-cutting phosphor bronze bar wire rod, which is obtained by cold working a processing copper alloy containing 6% by weight, 0.01 to 0.35% by weight of P, and the balance being Cu and inevitable impurities. The Rockwell hardness (HRB) is 74 or more .

A second method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention is as follows. Sn is 1.5 to 7.0% by weight, Ni is 0.5 to 7.0% by weight, and S is 0.02 to 0. A copper alloy for processing containing 6% by weight, 0.9% by weight or less of Fe (not including 0% by weight), 0.01 to 0.35% by weight of P, and the balance of Cu and inevitable impurities. A method of manufacturing a lead-free free-cutting phosphor bronze rod wire formed by cold working, characterized by having a Rockwell hardness (HRB) of 74 or more .

In the method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention, the content of Sn and the content of Ni satisfy the relationship of 2.5%≦1.3Sn+Ni≦9.2% in weight %. In addition, it is possible to adopt a configuration in which the relationship of 3.5%≦1.3Sn+Ni≦8.5% by weight% is satisfied.

In the method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention, it is possible to adopt a configuration in which Sn is 3.5 to 6.5% by weight.

The lead-free free-cutting phosphor bronze rod wire of the present invention can obtain high strength required for parts using phosphor bronze, and also has excellent machinability, and therefore requires precision such as thin parts and fine parts. There is an advantage that processing is possible.

Further, since the lead-free free-cutting phosphor bronze rod wire of the present invention has better conductivity than the conventional free-cutting phosphor bronze, it also has an advantage that it can be used for applications where performance has hitherto been impossible.

By using the method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention, the high strength required for parts using phosphor bronze can be obtained, and the machinability is also excellent. There is an advantage that a bronze rod wire can be manufactured.

The first lead-free free-cutting phosphor bronze rod wire of the present invention comprises Sn in an amount of 1.5 to 7.0% by weight, Ni in an amount of 0.5 to 7.0% by weight, and S in an amount of 0.02 to 0.6% by weight. the P containing 0.01 to 0.35 wt%, Ri Do the remainder of Cu and inevitable impurities, Rockwell hardness (HRB) is Ru der 74 or more.

In the present invention, the Sn content is 1.5 to 7.0% by weight, and the Sn content of less than 1.5% by weight provides the strength required for a component. This is because, on the contrary, when the Sn content exceeds 7.0% by weight, cracking occurs and plastic working becomes difficult.

Here, the Sn content is preferably 3.5 to 6.5% by weight. This is because when Sn is contained in an amount of 3.5 to 6.5% by weight, a very high strength rod wire can be obtained.

In the present invention, the Ni content is 0.5 to 7.0% by weight, because the Ni content is less than 0.5% by weight, the strength is insufficient and the strength in forming a component Is insufficient, and if the Ni content exceeds 7.0% by weight, the plastic workability deteriorates.

The Ni content is preferably 0.7% by weight or more because the effect of the invention may not be stably obtained, and if the importance of stably obtaining the effect of the invention is 0. It is more preferably 9% by weight or more.

In the present invention, considering the strength, the electrical conductivity, and the machinability comprehensively, and also considering the plastic workability, the Sn content and the Ni content are 2.5%≦1.3Sn+Ni in weight %. It is more preferable to satisfy the relationship of ≦9.2%, and if importance is attached to the electrical conductivity, the Sn content and the Ni content are 3.5%≦1.3Sn+Ni≦8.5% in weight %. It is even more preferable to satisfy.

In the present invention, the content of S is 0.02 to 0.6% by weight. When the content of S is less than 0.02% by weight, the machinability required for cutting is obtained. This is because the shavings are connected for a long time, and conversely, if the content of S exceeds 0.6% by weight, a uniform molten metal cannot be obtained when melt-casting the copper alloy for processing, and a normal alloy is obtained. Because you can't make.

In the present invention, the content of P is 0.01 to 0.35% by weight, because if the content of P is less than 0.01% by weight, the deoxidizing effect during dissolution becomes insufficient. On the contrary, when the P content exceeds 0.35% by weight, the plastic workability is deteriorated. Note that the P content is preferably 0.25% by weight or less because more stable plastic workability can be obtained.

Examples of elements that can be contained as impurities in the present invention include iron, silver, carbon, zirconium, manganese, bismuth, indium, selenium, aluminum, oxygen, boron, tungsten, zinc, antimony, silicon, and lead. The content of each of these is preferably less than 0.05% by weight, and more preferably less than the detection limit.

The second lead-free free-cutting phosphor bronze rod wire of the present invention comprises Sn in an amount of 1.5 to 7.0% by weight, Ni in an amount of 0.5 to 7.0% by weight, and S in an amount of 0.02 to 0.6% by weight. , Fe 0.9 wt% or less (not including 0% by weight.) the P containing 0.01 to 0.35 wt%, Ri do the remainder of Cu and inevitable impurities, Rockwell hardness (HRB ) is Ru der 74 or more.

In the second lead-free free-cutting phosphor bronze rod wire of the present invention, the Fe content is less than 0.9% by weight (not including 0% by weight). This is because a good quality material with few defects can be efficiently obtained when the copper alloy for casting is melt-cast, but if the Fe content exceeds 0.9% by weight, the machinability deteriorates. .. The Fe content is preferably 0.5 wt% or less because more stable machinability can be obtained.

Since the lead-free free-cutting phosphor bronze rod wire according to the present invention has good weldability, continuous wire drawing is possible by welding a coil having a small single weight.

The method for obtaining the lead-free free-cutting phosphor bronze rod wire of the present invention is not particularly limited, and a known method can be used, but cold working is preferable.

The first method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention is 1.5 to 7.0 wt% Sn, 0.5 to 7.0 wt% Ni, and 0.02 to 0. 6 wt%, contains P 0.01 to 0.35 wt%, the machining copper alloy of the balance of Cu and unavoidable impurities, Ri Na cold working, Rockwell hardness (HRB) 74 Ru der above.

Further, the second method for producing a lead-free free-cutting phosphor bronze rod wire according to the present invention comprises Sn at 1.5 to 7.0 wt%, Ni at 0.5 to 7.0 wt%, and S at 0.02. 0.6% by weight, 0.9% by weight or less of Fe (not including 0% by weight), 0.01 to 0.35% by weight of P, and the balance being Cu and unavoidable impurities for processing. the alloy, Ri Na cold working, Rockwell hardness (HRB) is Ru der 74 or more.

Regarding the manufacturing method of the lead-free free-cutting phosphor bronze rod wire of the present invention, the description of the same parts as those of the lead-free free-cutting phosphor bronze rod wire of the present invention will be omitted.

Examples of the cold working include cold rolling, cold forging, cold wire drawing and the like. The number of cold workings is not particularly limited, but is preferably 4 or more in order to obtain a uniform structure. In addition, it is preferable to perform annealing after the cold working.

Hereinafter, the present invention will be described more specifically based on Examples, but the present invention is not limited to these Examples.

(Preparation of test piece)
First, the addition amount of Sn, the addition amount of Ni, the addition amount of Fe, the addition amount of S, the addition amount of P, and the addition amount of Pb are appropriately changed, and the rest are added as Cu and inevitable impurities, and then mixed. Then, alloy materials 1 to 11 and alloy materials R1 to R7 were prepared, and the components were analyzed.

Table 1 shows the results of the component analysis of the alloy materials 1 to 11 and the alloy materials R1 to R7.

Next, for each of the alloy materials 1 to 11 and the alloy materials R1 to R7, the melting temperature was set to 1200° C., and after an ingot was manufactured by a die casting method, cold rolling with a working rate of about 20% and 650° C. After repeating the annealing and performing the fourth cold rolling, the lead-free free-cutting phosphor bronze rod wires 1 to 11 of the present invention as examples and the lead-free free-cutting phosphor bronze rod wires R1 to R3 and R5 as comparative examples. , R7, and lead-free free-cutting phosphor bronze rod wire R6 were obtained.

Regarding the alloy material R4 as well, after the melting temperature was set to 1200° C. and an ingot was produced by a die casting method, cold rolling at a working rate of about 20% and annealing at about 650° C. were repeated, but fracture occurred, No lead-free free-cutting phosphor bronze rod wire was obtained. From this result, it became clear that plastic working is difficult when the Sn content exceeds 7.0% by weight.

Next, lead-free free-cutting phosphor bronze rods 1 to 11 (Examples 1 to 11), lead-free free-cutting phosphor bronze rods R1 to R3, R5, R7 (Comparative Examples 1 to 5, 5, 7), leaded free-cutting. For each of the bronze rod wires R6 (Comparative Example 6), a test piece having a diameter of 20 mm and a length of 50 mm was prepared and designated as test pieces 1 to 11, test pieces R1 to R3, and R5 to R7.

(Test Example 1) Hardness Test For each of the test pieces 1 to 11 (Examples 1 to 11) and the test pieces R1 to R3 (Comparative Examples 1 to 3), ARK24129 manufactured by Akashi Co., Ltd. (currently Mitutoyo Co., Ltd.) was used. Then, using a steel ball having a diameter of 1/16 in (1.588 mm), a preliminary load of 10 kgf was first applied, and then 90 kgf was added, so that a total test load of 100 kgf was applied. After about 30 seconds, the preload (10 kgf) was restored. In this way, the Rockwell hardness (HRB) was obtained from 130-500 h from the difference in the depth of the depression (h scale of the dial gauge, where 1 scale is 0.002 mm) in the state of preload twice before and after. ..

Table 2 shows the measurement results of the Rockwell hardness (HRB) of the test pieces 1 to 11 and the test pieces R1 to R3.

For the test pieces 1 to 11 (Examples 1 to 11) in which the Sn content is 1.5 wt% or more and the Ni content is 0.5 wt% or more, all are 74 or more. , The high hardness required for parts using phosphor bronze can be obtained, and it can be predicted that, for example, the bending strength, header workability, and wear resistance will be excellent, but the Sn content is less than 1.5% by weight. For the test piece R3 (Comparative Example 3), the test piece R1 (Comparative Example 1) and the test piece R2 (Comparative Example 2) having a Ni content of less than 0.5% by weight, both are less than 74, It was found that the hardness required for parts using phosphor bronze cannot be obtained.

It was also found that the test pieces 8 to 11 (Examples 8 to 11) in which the Sn content was 3.5 to 6.5% by weight exceeded 80 in all cases. From this result, it became clear that the free-cutting phosphor bronze rod wire of the present invention having a Sn content of 3.5 to 6.5% by weight has a very high hardness.

(Test Example 2) Machinability test For each of the test pieces 1 to 11 (Examples 1 to 11) and the test pieces R5 to R7 (Comparative Examples 5 to 7), a general-purpose lathe LPT-35C manufactured by Wasino Machinery Co., Ltd. was used. The number of revolutions was 450 rpm, the feed pitch was 0.75 mm, and the cutting depth was 0.5 mm.

Then, the weight of 10 cutting scraps generated during the chamfering was measured by an electronic balance AUX120 manufactured by Shimadzu Corporation.

Table 3 shows the measurement results of the weight of 10 cutting chips for the test pieces 1 to 11 and the test pieces R5 to R7.

In all of the test pieces 1 to 11 (Examples 1 to 11), the cutting waste was not connected and was fine, the weight of 10 cutting wastes was less than 0.3 g, and even if lead was not included. It was found that the machinability was excellent. On the other hand, with respect to the test piece R5 containing no S, the cutting waste was connected for a long time, and the weight of 10 cutting wastes also exceeded 20 g.

Even in the case of the test piece R6 containing lead (Japanese Industrial Standard JIS H3270 C5341), cutting waste was connected, and the weight of 10 cutting wastes also exceeded 2 g. From this result, it became clear that the machinability of the lead-free free-cutting phosphor bronze rod wire of the present invention is considerably superior to that of the lead-free free-cutting phosphor bronze rod wire.

Further, with respect to the test piece R7 (Japanese Industrial Standard JIS H3270 C5191), the cutting waste was completely connected, and the number of the cutting waste was less than 10. Therefore, the weight of the 10 cutting scraps could not be measured. ..

(Test Example 3) Conductivity Test For each of the test pieces 1 to 11 (Examples 1 to 11) and the test piece R7 (Comparative Example 7), SIGMATEST 2.069 manufactured by FOERSTER was used to directly contact the measurement terminals. The conductivity was measured. Specifically, after calibrating with the attached standard test piece (pure copper, nickel silver), the cross section of each test piece was measured three times, and the average value was used as the measured value.

Table 4 shows the measurement results of the electrical conductivity of the test pieces 1 to 11 and the test piece R7.

The test piece R7 (Comparative Example 7) had a value of 13.0, but the test pieces 1 to 11 (Examples 1 to 11) each had a value of more than 13.5. It was found that the bronze rod wire has better conductivity than the conventional free-cutting phosphor bronze rod wire.

Moreover, the content of Sn and the content of Ni satisfy|fill the relationship of 3.5%<=1.3Sn+Ni<=8.5% by weight%, The test piece 1-3, 5-9 (Examples 1-3). , 5 to 9), all exceeded 16. From this result, the free-cutting phosphor bronze rod wire of the present invention, which satisfies the relation of 3.5%≦1.3Sn+Ni≦8.5% in terms of Sn content and Ni content in weight %, is particularly conductive. It became clear that it is excellent in sex.

Claims (10)

Sn: 1.5-7.0 wt%, Ni: 0.5-7.0 wt%, S: 0.02-0.6 wt%, P: 0.01-0.35 wt%, A lead-free free-cutting phosphor bronze rod wire having a balance of 74 or more, which is a lead-free free-cutting phosphor bronze rod wire consisting of Cu and inevitable impurities. Sn: 1.5-7.0 wt%, Ni: 0.5-7.0 wt%, S: 0.02-0.6 wt%, Fe: 0.9 wt% or less (including 0 wt% A lead-free free-cutting phosphor bronze rod wire containing 0.01 to 0.35% by weight of P and the balance Cu and unavoidable impurities, and having a Rockwell hardness (HRB) of 74 or more. Lead-free free-cutting phosphor bronze rod wire characterized by the following. The lead-free free-cutting according to claim 1 or 2, wherein the content of Sn and the content of Ni satisfy a relationship of 2.5% ≤ 1.3 Sn + Ni ≤ 9.2% by weight. Bronze rod wire. The lead-free free-cutting phosphor bronze according to claim 3, wherein the content of Sn and the content of Ni satisfy the relationship of 3.5%≦1.3Sn+Ni≦8.5% in weight %. Rod wire. The lead-free free-cutting phosphor bronze rod wire according to claim 1 or 2, wherein the Sn is 3.5 to 6.5% by weight. Sn: 1.5-7.0 wt%, Ni: 0.5-7.0 wt%, S: 0.02-0.6 wt%, P: 0.01-0.35 wt%, A method of manufacturing a lead-free free-cutting phosphor bronze rod wire, which is obtained by cold working a copper alloy for processing, the balance of which is Cu and unavoidable impurities, characterized by having a Rockwell hardness (HRB) of 74 or more. Lead-free free-cutting phosphor bronze rod wire manufacturing method. Sn: 1.5-7.0 wt%, Ni: 0.5-7.0 wt%, S: 0.02-0.6 wt%, Fe: 0.9 wt% or less (including 0 wt% In the manufacturing method of a lead-free free-cutting phosphor bronze rod wire rod, which is obtained by cold working a processing copper alloy containing 0.01 to 0.35% by weight of P and the balance of Cu and unavoidable impurities. A method for producing a lead-free free-cutting phosphor bronze rod wire , which has a Rockwell hardness (HRB) of 74 or more . The lead-free free-cutting according to claim 6 or 7, wherein the content of Sn and the content of Ni satisfy a relationship of 2.5% ≤ 1.3 Sn + Ni ≤ 9.2% by weight. Bronze rod wire manufacturing method. 9. The lead-free free-cutting phosphor bronze according to claim 8, wherein the Sn content and the Ni content satisfy the relationship of 3.5%≦1.3Sn+Ni≦8.5% by weight. Manufacturing method of rod and wire. The method for producing a lead-free free-cutting phosphor bronze rod wire according to claim 6 or 7, wherein the Sn is 3.5 to 6.5% by weight.