KR100444291B1 - High strength phosphorous copper with fine grain structure - Google Patents

Abstract

The present invention relates to a copper (Cu) -tin (Sn) -phosphorus (P) -cerium (Ce) -lanthanum (La) -based phosphor bronze alloy for high strength springs and a method of manufacturing the same, and an object thereof is conventional copper-tin The present invention relates to a new high strength alloy having excellent hot and cold workability by adding tin and phosphorus as main alloy elements and adding elements that can control the material strength and microstructure in the phosphorus alloy.

In the alloy of the present invention, in the phosphor bronze for high strength spring, 5.0 to 9.0 wt% (wt%) tin (Sn), 0.1 to 0.5 wt% (wt%) phosphorus (P), and 0.001 to 0.1 wt% % (Weight percent) cerium (Ce) and 0.001-0.1 wt% (weight percent) lanthanum (La) are added thereto, but the addition ratio of cerium (Ce) and lanthanum (La) is about 2: 1. The rest is based on the alloy made of copper (Cu).

Description

High strength phosphorous copper with fine grain structure for copper, tin, phosphorus, phosphorus, cerium and lanthanum phosphorescent alloys

The present invention relates to a copper (Cu) -tin (Sn) -phosphorus (P) -cerium (Ce) -lanthanum (La) -based phosphor bronze alloy for high strength springs. The present invention relates to a new alloy that can reduce manufacturing costs, improve processability of ingots, improve productivity, and improve the properties of phosphor bronze itself.

In the manufacture of high-strength phosphor bronze for spring, the prior art has added 9% tin and 9% tin in an alloy containing 7-9% tin and 0.03-0.35% phosphorus as in the current KS, JIS, ASTM and UNS. Tensile strength of up to 900 MPa is satisfied in the practical products produced by conventional equipment for 0.3% added alloys.

In the case of high-elastic spring phosphor bronze containing 7-9% of tin (Sn), a large amount of tin with low melting point of 232 ℃ is segregated at the grain boundary grains grown with the solidification structure of the ingot and hot plastic processing is performed. Of course, plastic working is very difficult even at room temperature. This causes the internal frictional heat generated by the plastic working even at room temperature plastic processing, and the ingot is broken while the tin of the columnar grain boundary melts.

Therefore, the phosphor bronze ingot has a disadvantage in that it does not increase the plastic working rate by 20-25% or more or accumulate the total processing rate by 60-70% or more so that internal frictional heat is generated even during plastic working at room temperature.

An object of the present invention for solving the above problems is that in the existing copper-tin-phosphorus alloy, tin and phosphorus as the main alloying elements and by adding elements that can control the material strength and microstructure, hot and cold workability To provide an excellent new high-strength alloy, firstly, by inoculating treatment, the solidified columnar structure is fined and oriented so that tin is finely dispersed in the matrix to prevent cracking of the ingot due to internal frictional heat during plastic processing and to achieve a plastic working rate. And increase the overall processing rate to improve productivity and material integrity.Secondly, cerium and lanthanum are combined with copper and tin and other complex phases such as CuxCe, CuyLa, CuxCeyLa and Cu-Sn complex phases. It is to provide an alloy with high strength of the material due to the solid solution strengthening property to form in the solid solution in the base.

That is, 1) miniaturization of columnar tissue and orientation removal of coagulated tissue by inoculation treatment, 2) crack prevention of ingot during plastic working, increase of plastic working rate and total processing rate, and 3) processing hardening process by increasing total processing rate. To improve the strength of the material, and 4) to provide alloys with improved strength through solid solution effects such as fine composite compounds or composite phases by the addition of cerium and lanthanum as inoculum elements.

The most important technique in the above is the discovery of an inoculation effect element capable of miniaturizing the solidification structure of the phosphor bronze alloy and its application to the copper and tin which are the main constituents of phosphor bronze, which has a narrow solid solubility limit. Finding the most suitable transition element with this strong feature is to maximize the application effect.

1 is a cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm of Cu-7% Sn-0.3% P alloy, which is general phosphor bronze, and 2: 1 of cerium (Ce) and lanthanum (La) in a general phosphor bronze alloy component. Cu-7% Sn-0.3% P-0.03% (Ce + La) (b), Cu-7% Sn-0.3% P-0.05% (Ce + La) c) and Cu-7% Sn-0.3% P-0.1% (Ce + La) (d) microstructure of ingot,

FIG. 2 is a cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm of Cu-8% Sn-0.3% P alloy of general phosphor bronze, and cerium (Ce) and lanthanum (La) of 2: 1 in a general phosphor bronze alloy component. Cu-8% Sn-0.3% P-0.03% (Ce + La) (b), Cu-8% Sn-0.3% P -0.05% (Ce + La) c) and Cu-8% Sn-0.3% P-0.1% (Ce + La) (d) microstructure of ingot,

FIG. 3 shows 2: 1 of cerium (Ce) and lanthanum (La) in the cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm of a general phosphor bronze Cu-9% Sn-0.3% P alloy and a common phosphor bronze alloy component. Cu-9% Sn-0.3% P-0.03% (Ce + La) (b), Cu-9% Sn-0.3% P-0.05% (Ce + La) c) and Cu-9% Sn-0.3% P-0.1% (Ce + La) (d) Microstructure of ingot.

The composition of the high-strength spring phosphor bronze for the present invention, which achieves the object as described above and performs the problem for eliminating the conventional defect, is 5.0 to 9.0 wt% (% by weight) tin (Sn), and 0.1 to 0.5 wt. % (Wt%) phosphorus (P), 0.001-0.1 wt% (wt%) cerium (Ce), and 0.001-0.1 wt% (wt%) lanthanum (La) to this The addition ratio of (Ce) and lanthanum (La) was about 2: 1 and the rest was composed of copper (Cu).

In the above, tin and phosphorus were added to maintain the basic composition range of the commercial alloy as the main additive element of phosphor bronze.

The cerium and lanthanum 1) remove the orientation of the microstructure and coagulation structure of the columnar tissue by inoculation treatment, 2) prevent cracking of the ingot during plastic working, and increase the plastic working rate and total processing rate, 3) total In addition to improving the strength of the material by increasing the processing rate, 4) reducing the amount of expensive tin added due to the solid solution effect of fine complex compounds or composite phases by the addition of cerium and lanthanum as inoculation elements. A new material was added to improve the strength of phosphor bronze itself.

The most important technique here is the discovery of inoculation effect elements that can refine the solidification structure of phosphor bronze alloys and its application. As a result, the solid solution limit is narrow for copper and tin, which are the main components of phosphor bronze, and the reactivity to form compounds by alloying them It is to find the most suitable transition element with strong characteristics and maximize its application effect.

As a result, a high-strength spring phosphor bronze having a fine matrix structure and a tensile strength of 950 Mpa or more and an elongation of 10% or more could be produced by proper annealing heat treatment and cold working.

The reason for each numerical limitation in the composition of the present invention is;

According to the results of the experiment, the transition from the ingot state to the refined columnar crystals of the high-strength spring phosphor bronze, which acts as a solid solution element to copper and tin, and forms a variety of compounds with high alloy reactivity during annealing heat treatment and cold plastic working The elements selected by various experiments to find the elements are cerium and lanthanum, and combining these alloys could achieve the purpose more effectively.

The reason for limiting tin and phosphorus to 5.0 to 9.0 wt% (weight percent) and 0.1 to 0.5 wt% in the composition of the present invention is beyond the basic composition of practical phosphor bronze in a limited composition range, and cold workability is extremely poor. This is because there are many problems in practicality such as no improvement in strength or ductility of the material compared to the manufacturing cost.

In the composition of the present invention, cerium and lanthanum are added in an amount of 0.001 to 0.1 wt% (weight percent) and 0.001 to 0.1 wt% (weight percent), respectively, and an addition ratio of cerium (Ce) and lanthanum (La) is 2 The reason for limiting to about 1 is that the workability is difficult due to the poor flowability of the molten metal during melting and refining above the limited composition range, and the cold workability is very poor and the ductility is low in the process after the ingot process. This problem is large, such that there is a disadvantage that the characteristics of the target material are not satisfied below the composition range.

The composition of the high-strength spring phosphor bronze for the composition as described above is 5.0 to 9.0 wt% (% by weight) tin (Sn), 0.1 to 0.5 wt% (% by weight) phosphorus (P), and 0.001 to 0.1 Wt% (wt%) cerium (Ce) and 0.001-0.1 wt% (wt%) lanthanum (La) are added thereto, but the addition ratio of cerium (Ce) and lanthanum (La) is about 2: 1. And the rest is weighed with copper (Cu),

After weighing, start dissolving copper (Cu) at the bottom of the furnace first, and then remove all the slag when all the copper is dissolved. Then, when the molten metal reaches about 1,100 ℃, stop heating or supply very low heat source. After charging and dissolving tin (Sn), and then adding a phosphorus phosphorus phosphorus (P) phosphorus to the plunger and stirred well to dissolve,

When the alloying elements are sufficiently dissolved and the melt temperature is about 1100 to 1150 ° C., the flowability of the melt is improved. The cerium (Ce) and the lanthanum (La), which are inoculation treatment elements, are added together with a plunger and stirred well to melt the melt 1100 to 1150. Manufacturing a bar or a plate by continuous casting immediately after stabilization at a range of ℃,

The plate or rod, which is a continuous cast ingot manufactured as described above, is homogenized for 1 hour in the range of 700 to 800 ° C., and then the casting structure is completely removed by plastic processing of 85% or more by cold rolling or cold drawing, and then it is 500 to 700 ° C. 2-5 hours at the temperature of the water and then cooled to perform the first annealing heat treatment, and then cold processing of about 50-80% again, it is maintained for 3 to 5 hours at a temperature of 350 ~ 550 ℃, water cooled to the second Annealing heat-treatment is carried out to produce a high-strength spring phosphor bronze plate or wire for the desired quality by cold processing of about 10 to 95%.

In the process of repeating the annealing heat treatment and cold working, cerium and lanthanum form another complex phase combined with copper and tin and CuxCe, CuyLa, CuxCeyLa, and Cu-Sn composite phases. Due to the employment-reinforcement characteristics employed, the strength of cold processed materials is further increased.

Hereinafter, the configuration and the operation of the embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm of Cu-7% Sn-0.3% P alloy, which is general phosphor bronze, and 2: 1 of cerium (Ce) and lanthanum (La) in a general phosphor bronze alloy component. Cu-7% Sn-0.3% P-0.03% (Ce + La) (b), Cu-7% Sn-0.3% P-0.05% (Ce + La) c) and Cu-7% Sn-0.3% P-0.1% (Ce + La) (d) Ingot microstructure.

FIG. 2 shows 2: 1 of cerium (Ce) and lanthanum (La) in the cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm and a common phosphor bronze alloy component of Cu-8% Sn-0.3% P alloy of general phosphor bronze. Cu-8% Sn-0.3% P-0.03% (Ce + La) (b), Cu-8% Sn-0.3% P -0.05% (Ce + La) c) and Cu-8% Sn-0.3% P-0.1% (Ce + La) (d) Ingot microstructure.

FIG. 3 shows 2: 1 of cerium (Ce) and lanthanum (La) in the cross-sectional microstructure (a) of a rod-shaped ingot having a diameter of 30 mm of a general phosphor bronze Cu-9% Sn-0.3% P alloy and a common phosphor bronze alloy component. Cu-9% Sn-0.3% P-0.03% (Ce + La) (b), Cu-9% Sn-0.3% P-0.05% (Ce + La) c) and Cu-9% Sn-0.3% P-0.1% (Ce + La) (d) Ingot microstructure.

As a result, a high-strength spring phosphor bronze alloy having a tensile strength of 700 to 965 Mpa and an elongation of 5 to 15% was provided through a suitable annealing heat treatment and cold plastic working, and a manufacturing method thereof.

1, 2, and 3, each photograph (a) is not inoculated and the photographs (b), (c) and (d) are inoculated. Here, in the photograph (a) without inoculation treatment, the columnar tablets, which are cast tissues, are highly developed with direction, but in the case of inoculation treatments (b), (c), and (d), the cast tissues are very fine and uniform. Seems to have changed.

The following Table 1 is an example of the alloys presented in the present invention, Table 2 shows the changes in tensile strength, elongation and hardness of 75% cold rolling after annealing heat treatment at 480 ℃ for 5 hours for temper treatment, Cu In the case of -9Sn-0.3P-0.1Ms, the tensile strength is 966 MPa and the elongation is 12%.

Table 3 shows the tensile strength, elongation, and hardness of the Cu-8Sn-0.3P-0.03Ms alloy after annealing at 480 ° C. for 5 hours. Tensile strength was increased to 977 MPa or more, and a good level of elongation of 8% was obtained.

In the above results, in the case of Cu-9% Sn-0.3% P alloy which can obtain the best tensile strength in the case of conventional utility products, the cold rolling rate is about 65% applied due to the difficulty in workability, and the tensile strength obtained at this time is Considering that 900 MPa, elongation is 10% or less, through the present invention, it is possible to manufacture a high-strength spring phosphor bronze having excellent properties of tensile strength of 960-970 MPa, elongation of about 8-10%.

[Table 1] Types of alloys and alloy components (wt%)

Alloy Cu Sn P Ms Cu-7Sn-0.3P Remainder 7 0.3 - Cu-7Sn-0.3P-0.001Ms Remainder 7 0.3 0.001 Cu-7Sn-0.3P-0.03Ms Remainder 7 0.3 0.03 Cu-7Sn-0.3P-0.05Ms Remainder 7 0.3 0.05 Cu-7Sn-0.3P-0.1Ms Remainder 7 0.3 0.10 Cu-8Sn-0.3P Remainder 8 0.3 - Cu-8Sn-0.3P-0.001Ms Remainder 8 0.3 0.001 Cu-8Sn-0.3P-0.01Ms Remainder 8 0.3 0.01 Cu-8Sn-0.3P-0.03Ms Remainder 8 0.3 0.03 Cu-8Sn-0.3P-0.05Ms Remainder 8 0.3 0.05 Cu-8Sn-0.3P-0.1Ms Remainder 8 0.3 0.10 Cu-9Sn-0.3P Remainder 9 0.3 - Cu-9Sn-0.3P-0.001Ms Remainder 9 0.3 0.001 Cu-9Sn-0.3P-0.03Ms Remainder 9 0.3 0.03 Cu-9Sn-0.3P-0.05Ms Remainder 9 0.3 0.05 Cu-9Sn-0.3P-0.1Ms Remainder 9 0.3 0.10

[Table 2] Change in tensile strength, elongation and hardness after 75% cold rolling after annealing heat treatment at 480 ℃ for 5 hours

Alloy T.S (MPa) El (%) Hardness (Hv) Cu-7Sn-0.3P 880 10 Cu-7Sn-0.3P-0.03Ms 890 13 Cu-7Sn-0.3P-0.05Ms 910 13 Cu-7Sn-0.3P-0.1Ms 931 15

Alloy T.S (MPa) El (%) Hardness (Hv) Cu-8Sn-0.3P 903 11 Cu-8Sn-0.3P-0.01Ms 927 16 Cu-8Sn-0.3P-0.03Ms 931 13 Cu-8Sn-0.3P-0.05Ms 944 12 Cu-8Sn-0.3P-0.1Ms 949 13

Alloy T.S (MPa) El (%) Hardness (Hv) Cu-9Sn-0.3P 928 10 Cu-9Sn-0.3P-0.03Ms 958 14 Cu-9Sn-0.3P-0.05Ms 960 12 Cu-9Sn-0.3P-0.1Ms 966 12

[Table 3] Tensile Strength, Elongation and Hardness of Cu-8Sn-0.3P-0.03Ms Alloy According to Cold Rolling Rate after Annealing Heat Treatment at 480 ° C for 5 Hours

Cold rolling rate (%) T.S (MPa) El (%) Hardness (Hv) 0 465 65 119 37 670 20 206 59 865 14 253 75 931 11 262 85 977 8 271

Hereinafter is a preferred embodiment of the present invention.

(Example and Comparative Example 1)

A total amount of alloy is targeted to 1,000 kg of Cu-7Sn-0.3P, which is a conventional phosphor bronze alloy system, and 927 kg of copper is first dissolved according to each alloy composition ratio, followed by melting by adding 70 kg of tin and then 3 kg. The ingot was prepared by continuously casting phosphor bronze, Cu-7Sn-0.3P, into a plate shape having a thickness of 15 mm and a width of 300 mm at 1180 ° C., maintaining it at 750 ° C. for 1 hour, and then cooling and homogenizing it. First, cold rolling was performed to a thickness of 5 mm. After holding for 3 hours at 600 ° C., it was cooled and annealed, and then secondarily cold rolled to 1 mm. After heating at 450 ° C. for 4 hours, the mixture was cooled and prepared for tempering treatment, the product was produced to meet each quality requirement. .

As an example, when the material properties of the rolled material are rolled up to 0.25 mm by 75%, the tensile strength is 880 MPa, the elongation is 10%, and the electrical resistance is 16 μΩcm as shown in Table 2.

Compared to the above, in the case of Cu-7Sn-0.3P-0.1Ms in which 0.05% of cerium and lanthanum are added to the same Cu-7Sn-0.3P, 0.05% of tensile strength, 15% elongation and 15μΩcm Physical properties are greatly improved.

(Example and Comparative Example 2)

A total amount of alloy is targeted to 1,000 kg of Cu-8Sn-0.3P, which is a conventional phosphor bronze alloy system, and 917 kg of copper is first dissolved according to each alloy composition ratio, followed by melting by adding 80 kg of tin, followed by 3 kg. The ingot was prepared by continuously casting phosphor bronze, Cu-8Sn-0.3P, into a plate shape having a thickness of 15 mm and a width of 300 mm at 1180 ° C., maintaining it at 750 ° C. for 1 hour, and then cooling and homogenizing it. First, cold rolling was performed to a thickness of 5 mm. After holding for 3 hours at 600 ° C., it was cooled and annealed, and then secondarily cold rolled to 1 mm. After heating at 450 ° C. for 4 hours, the mixture was cooled and prepared for tempering treatment, the product was produced to meet each quality requirement. .

For example, when the material properties of the rolled material to 0.25 mm 75%, as shown in Table 2, the tensile strength is 903 MPa, elongation 11% and electrical resistance 18μΩcm.

Compared to the above, in the case of Cu-8Sn-0.3P-0.1Ms in which 0.05% of cerium and lanthanum are added to the same Cu-8Sn-0.3P, a tensile strength of 949 MPa, an elongation of 13%, and an electric resistance of 16 μΩcm Physical properties are greatly improved.

(Example and Comparative Example 3)

A total amount of alloy is targeted at 1,000 kg for Cu-9Sn-0.3P, a conventional phosphor bronze alloy system, and 907 kg of copper is first dissolved according to each alloy composition ratio, followed by melting by adding 90 kg of tin, and then 3 kg. Ingot was prepared by continuously casting phosphor bronze, Cu-9Sn-0.3P, into a plate having a thickness of 15 mm and a width of 300 mm at 1180 ° C. After cooling for 1 hour at 750 ° C, it was homogenized. First, cold rolling was performed to a thickness of 5 mm. After holding for 3 hours at 600 ° C., it was cooled and annealed, and then secondarily cold rolled to 1 mm. After heating at 450 ° C. for 4 hours, the mixture was cooled and prepared for tempering treatment, the product was produced to meet each quality requirement. .

As an example, when the material properties of the rolled material to 75% rolled to 0.25mm, as shown in Table 2, the tensile strength is 928 MPa, elongation 10% and electrical resistance 19μΩcm.

Compared to the above, in the case of Cu-9Sn-0.3P-0.1Ms in which 0.05% of cerium and lanthanum are added to the same Cu-9Sn-0.3P, a tensile strength of 966 MPa, an elongation of 12%, and an electrical resistance of 17 μΩcm Physical properties are greatly improved.

(Example and Comparative Example 4)

Targeting the total amount of alloy to 1,000kg for Cu-8Sn-0.3P-0.03Ms, the developed high-strength spring phosphor bronze alloy, dissolve 917kg of copper according to each alloy composition ratio and add 80kg of tin After melting, the phosphor bronze was added 3kg and phosphorus bronze, Cu-8Sn-0.3P-0.03Ms, in which 0.3 kg of the total amount of cerium and lanthanum were added, and the thickness was 15mm and 300mm in width. The ingot was prepared by continuous casting in a plate shape, and after maintaining it at 750 ° C. for 1 hour, it was cooled and homogenized, and then first cold rolled to a thickness of 5 mm. After holding for 3 hours at 600 ° C., it was cooled and annealed, and then secondarily cold rolled to 1 mm. After heating at 450 ° C. for 4 hours, the mixture was cooled and prepared for tempering treatment, the product was produced to meet each quality requirement. .

For example, in the case of rolling in the range of 37 to 75% from 0.63 to 0.15 mm, as shown in Table 3, the tensile strength varies from 670 to 797 MPa, elongation 8 to 20%, and hardness Hv 206 to 271. Could get

In the case where the cold rolling was not performed, tensile strength 465 MPa, elongation 65%, and hardness Hv 119 without reinforcing properties were shown.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

The present invention as described above relates to a copper (Cu) -tin (Sn) -phosphorus (P) -cerium (Ce) -lanthanum (La) -based phosphor bronze alloy for high strength springs, 1) columnar tissue by inoculation treatment Eliminates the direction of micronization and coagulation structure, 2) prevents cracking of ingot during plastic working, increases plastic working rate and total working rate, and 3) improves the strength of materials by hardening work by increasing total working rate. 4) A new material with the function of a new material that can enhance the strength of phosphor bronze itself while reducing the amount of expensive tin added due to the strengthening effect of fine complex compounds or composite phases by the addition of cerium and lanthanum inoculation elements. Leeum (Ce) and lanthanum (La) were added.

In other words, in the process of repeating annealing heat treatment and cold working on the existing phosphor bronze, the combination of copper and tin and fine complexes of CuxCe, CuyLa, CuxCeyLa, and Cu-Sn complex phases was added by the addition effect of cerium and lanthanum. The formation of other composite phases, etc., has the advantage of further increasing the strength of cold-worked materials due to the solid solution strengthening properties employed in the base. By this advantage, the industrial use is expected to be greatly expected.

Claims (2)

In the manufacture of high-strength spring phosphor bronze, 5.0 to 9.0 wt% (wt%) tin (Sn), 0.1 to 0.5 wt% (wt%) phosphorus (P), 0.001-0.1 wt% (wt%) cerium (Ce), To this, 0.001 to 0.1 wt% (weight percent) lanthanum (La) is added, but the addition ratio of cerium (Ce) and lanthanum (La) is about 2: 1, and the rest is composed of copper (Cu). High strength spring copper (Cu)-tin (Sn)-phosphorus (P)-cerium (Ce)-lanthanum (La) based phosphor bronze alloy. delete