KR102468119B1 - Copper-Tin alloy for hot rolling and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a copper-tin alloy capable of hot rolling and a method for manufacturing the same.

Description

Copper-Tin alloy for hot rolling and method for manufacturing thereof

The present invention relates to a copper-tin alloy capable of hot rolling and a method for manufacturing the same.

Copper alloy has been widely used as an electric and electronic material due to its excellent malleability and ductility and high electrical conductivity. can However, as the number and amount of added elements increase, the electrical conductivity rapidly decreases, and thus the use as an electrical and electronic material has been limited.

In general, there is a trade-off relationship between electrical conductivity and strength of copper alloys. When the strength is increased, the electrical conductivity is reduced, and when the electrical conductivity is improved, a problem occurs in that the strength is lowered according to the microstructure change.

In order to respond to the recent trend of light, thin, compact and high-density mounting of electrical and electronic components such as connectors, it is required to improve the shape and dimensional accuracy of bent products, and accordingly, high strength materials, high electrical conductivity, and high springs are required. is continuing

Representative copper alloys used for connectors and terminals so far include brass (Cu-Zn series), phosphor bronze (Cu-Sn-P series), and beryllium copper (Cu-Be series). Although strength and hardness can be obtained, there are disadvantages such as being expensive, easily oxidized, difficult to process due to too high hardness, and generating harmful substances during processing. Although brass is inexpensive and exhibits excellent characteristics in formability and processability, product reliability is poor due to low strength and poor stress corrosion cracking resistance.

Phosphor bronze is manufactured by adding 3 to 15% Sn, and exhibits excellent properties in terms of reliability, strength, spring property, etc., but is expensive due to low electrical conductivity and expensive tin content, and minimizes tin segregation during solidification. There is a problem that the rolling conditions must be strictly controlled to prevent cracking during rolling.

Therefore, as a substitute for brass and phosphor bronze, demand for bronze added with Sn is increasing. 1 shows a graph of phase change of bronze according to the amount of Sn added and the temperature. According to FIG. 1, bronze is a solid solution strengthening alloy in which the solid solubility of Sn is 15 wt%, and although it has a high solid solubility, segregation may occur at grain boundaries, and Sn-rich segregation occurs when high heat is applied, It becomes liquid or deforms under low stress.

Figure 2 is a SEM showing the crack area in the alloy hot-swaged with 90% of the Cu-6Ni-2Mn-2Sn-2Al alloy (Fig. 2 (a)) and the state of the cast alloy (Fig. 2 (b)) It is a micrograph. According to FIG. 2, it can be confirmed that cracks may occur in segregation when bronze is processed at a high temperature. Even if solution treatment or homogenization treatment is performed at high temperature to eliminate segregation, it is known that hot working is impossible for copper alloys to which Sn is added because voids remain at the location where segregation occurred.

As a background art of the present invention, Korean Patent No. 10-10064451 discloses copper (Cu)-nickel (Ni)-manganese (Mn)-silicon (Si)-tin (Sin) for high-strength lead frame materials with improved hot workability and softening properties. -Mishmetal (MS)-based alloy and its manufacturing method are disclosed.

An object of the present invention is to provide a copper-tin alloy capable of being hot rolled by preventing the occurrence of segregation of tin or the occurrence of cracks in segregation, and a manufacturing method thereof.

Another object of the present invention is to provide a method for producing a copper-tin alloy, in which a more stable compound can be produced at a location where segregation occurs, casting crystal grains are refined, and hot workability is improved.

Other objects and advantages of the present invention will become more apparent from the following detailed description, claims, and drawings.

According to one aspect, based on 100 parts by weight of the copper alloy, 4 to 22 parts by weight of Sn; 0 to 1.0 parts by weight of P; 0.1 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and Cu and the remainder of unavoidable impurities; wherein Co and Ti are dissolved in Sn segregation, and are selected from Co-Ti compounds, Sn-Ti compounds, and Sn-Co compounds at grain boundaries. There is provided a copper-tin alloy capable of being hot-rolled, characterized in that it comprises at least one species that is.

According to one embodiment, the Co-Ti compound may be at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti.

According to one embodiment, the Sn-Ti compound may be at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ .

According to one embodiment, the Sn-Co compound may be at least one selected from Co ₃ Sn ₂ and CoSn.

According to one embodiment, the reduction rate of the cross-sectional area of the copper-tin alloy after hot rolling may be greater than 15%.

According to one embodiment, the total content of Co and Ti may be 0.3 parts by weight or more.

According to one embodiment, the value of (Co + Ti)/Sn may be 0.03 parts by weight or more.

According to another aspect, an article, which is a spring, a connector, a lead frame, or a component for semiconductor packaging, made of the above-described hot-rollable copper-tin alloy is provided.

According to another aspect, i) 4 to 22 parts by weight of Sn, based on 100 parts by weight of the copper alloy; 0 to 1.0 parts by weight of P; 0.1 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and the remainder of Cu and unavoidable impurities; casting a Cu-Sn alloy comprising; And ii) hot-rolling the cast Cu-Sn alloy; including, Co and Ti are dissolved in Sn segregation, and Co-Ti compound, Sn-Ti compound, and Sn-Co at the grain boundary A method for producing a copper-tin alloy capable of hot rolling, characterized in that it produces at least one selected from compounds is provided.

According to one embodiment, the hot rolling of step ii) may be performed at 750 °C to 850 °C.

According to one embodiment, in the method for manufacturing a copper-tin alloy capable of hot rolling, the Co-Ti compound may be at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti.

According to one embodiment, in the method for manufacturing a copper-tin alloy capable of hot rolling, the Sn-Ti compound may be at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ .

According to one embodiment, in the method for manufacturing a copper-tin alloy capable of hot rolling, the Sn-Co compound may be at least one selected from Co ₃ Sn ₂ and CoSn.

According to one embodiment, in the method for manufacturing a copper-tin alloy capable of being hot rolled, a reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy may be greater than 15%.

According to an embodiment, hot rolling of a copper-tin alloy is possible by adding cobalt and titanium, which react with tin and have high stability.

According to an embodiment, cobalt and titanium are dissolved in tin segregation, casting crystal grains of the copper-tin alloy are refined, and hot workability of the copper-tin alloy may be improved.

According to an embodiment, the hot workability of the copper-tin alloy may be improved by forming a Co-Ti compound, a Sn-Ti compound, and a Sn-Co compound at the grain boundary.

According to one embodiment, it is possible to facilitate hot rolling of the alloy in the manufacturing process of the copper-tin alloy, so that strength and spring properties can be improved.

1 is a graph showing the phase change of bronze according to the amount of Sn added and the temperature.
Figure 2 is a SEM showing the crack area in the alloy hot-swaged with 90% of the Cu-6Ni-2Mn-2Sn-2Al alloy (Fig. 2 (a)) and the state of the as-cast alloy (Fig. 2 (b)) It is a micrograph.
Figure 3a is a graph showing the phase change of the alloy according to the addition amount and temperature of titanium.
Figure 3b is a graph showing the phase change of the alloy according to the addition amount and temperature of tin.
Figure 3c is a graph showing the phase change of the alloy according to the addition amount and temperature of cobalt.
Figure 4 is a graph showing the phase fraction according to the temperature and equilibrium, equilibrium-cooling, and Sheil Gulliver-cooling of the Cu-8Sn-0.1P alloy (Alloy A).
5 shows the phase fraction according to the temperature and equilibrium, equilibrium-cooling, and Sheil Gulliver-cooling of the Cu-8Sn-0.1P-0.45Co-0.36Ti alloy (Alloy B).
6A is a graph showing hot rolling conditions of a copper-tin alloy.
6B is a photograph showing changes in casting crystal grains of the alloy according to the contents of phosphorus (P), cobalt (Co), and titanium (Ti) in the copper-tin alloy.
7 is a graph showing hot rolling conditions of a copper-tin alloy (FIG. 7(a)), and a cross-sectional area reduction rate and alloy according to phosphorus (P), cobalt (Co), and titanium (Ti) contents of the copper-tin alloy It is a photograph showing the change in appearance (FIG. 7 (b)).
8A is a graph showing hot rolling conditions of a copper-tin alloy.
8B is a photograph showing a reduction rate of cross-sectional area and a change in the appearance of the alloy according to the content of phosphorus (P), cobalt (Co), and titanium (Ti) in the copper-tin alloy.
9 is an image showing the change in inclusion amount of the alloy according to the contents of phosphorus (P), cobalt (Co), and titanium (Ti) in the copper-tin alloy.
Figure 10 shows the composition profile of the Sn-rich and deficient parts of the alloy (Alloy 6) of Comparative Example 2.
11 shows the composition profile of the Sn segregation portion of the alloy of Example 5 (Alloy 7).
12 shows the composition profile of the Sn segregation portion of the alloy of Example 6 (Alloy 8).
Figure 13 shows the composition profile of the Sn segregation portion of the alloy (Alloy 9) of Example 7.
14 shows the composition profile of the Sn segregation portion of the alloy (Alloy 10) of Example 8.
15 shows the composition profile of the Sn segregation portion of the alloy of Example 9 (Alloy 11).
16A is a graph showing hot rolling conditions of a copper-tin alloy.
16B is a photograph showing a cross-sectional area reduction rate according to phosphorus (P), cobalt (Co), and titanium (Ti) contents and hot rolling temperature of a copper-tin alloy and the appearance of the alloy.

Since the present invention can apply various transformations and have various embodiments, specific embodiments will be illustrated in the drawings and described in detail in the detailed description. However, it should be understood that this is not intended to limit the present invention to specific embodiments, and includes all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of related known technologies may obscure the gist of the present invention, the detailed description will be omitted.

Terms used in this application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this application, the terms "include" or "have" are intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Hereinafter, with reference to the accompanying drawings, a hot-rollable copper-tin alloy and a manufacturing method thereof according to the present invention will be described in detail.

According to one aspect, based on 100 parts by weight of the copper alloy, 4 to 22 parts by weight of Sn; 0 to 1.0 parts by weight of P; 0.1 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and Cu and the remainder of unavoidable impurities; wherein Co and Ti are dissolved in Sn segregation and selected from Co-Ti compounds, Sn-Ti compounds, and Sn-Co compounds at grain boundaries. A copper-tin alloy capable of hot rolling, characterized in that it comprises one or more, is provided.

Ti and Co, elements that react with tin and increase stability, are added to the copper-tin alloy to create a stable compound in copper itself. In addition, it was confirmed that the hot workability of the copper-tin alloy can be improved by suppressing Sn segregation or generating a stable compound at the grain boundary.

Sn has an excellent solid-solution strengthening effect in the copper alloy and has an effect of improving the stress relaxation resistance of the copper alloy sheet. 4 to 22 parts by weight of Sn may be suitable in terms of solid solution strengthening effect and stress relaxation resistance, 7 to 10 parts by weight may be more suitable, and 7 to 9 parts by weight may be more suitable. When the Sn content exceeds 22 parts by weight, the content of Sn, an element that is easily segregated, is relatively high, and cracks easily occur during hot rolling. Therefore, it is suitable that the Sn content is 22 parts by weight or less.

P improves the mechanical properties of the copper alloy sheet and acts as a deoxidizer when casting by melting the raw material of the copper alloy, thereby reducing the oxygen concentration of the molten metal. In order to exert the said effect, it is suitable that P content is more than 0 weight part. When the content of P exceeds 1.0 parts by weight, coarse precipitates are formed or the hydrogen concentration increases due to excessive deoxidation, so that cracks easily occur during casting bonding or hot rolling of the copper alloy sheet. Therefore, it is suitable that the content of P is 1.0 parts by weight or less.

Co and Ti are dissolved in the Cu matrix and contribute to improving the strength and spring properties of the copper alloy. Co and Ti react with Sn and can make stable compounds in copper themselves, contributing to the improvement of electrical conductivity and stress resistance.

Co has an effect of simultaneously improving the strength and conductivity of the copper alloy sheet, but is an expensive element, so the content of Co is preferably 0.1 parts by weight or more and 3.0 parts by weight or less. Since Co is an expensive element, when the content of Co exceeds 3.0 parts by weight, it is not cost-effective.

Although not limited thereto, according to one embodiment, the Co-Ti compound may be at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti, and Sn segregation forms a Co-Ti compound, The hot rolling properties of the alloy can be improved.

Although not limited thereto, according to one embodiment, the Sn-Ti compound may be at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ , and Sn and Ti react to form a copper matrix. It can form stable compounds in When stable compounds are formed at grain boundaries, copper-tin alloys with improved hot workability can be manufactured.

Although not limited thereto, according to one embodiment, the Sn-Co compound may be at least one selected from Co ₃ Sn ₂ and CoSn, and Sn and Co react to form a stable compound in a copper matrix. . When stable compounds are formed at grain boundaries, copper-tin alloys with improved hot workability can be manufactured.

Although not limited thereto, according to one embodiment, the reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy may be suitably greater than 15%, and may be more suitably greater than 20%. When the reduction rate of the cross-sectional area is 15% or less, only the surface layer is drawn, and a difference in structure between the inner and outer layers may occur, and the structure may be destroyed (crashing).

Although not limited thereto, according to one embodiment, the total content of Co and Ti is 0.3 parts by weight or more suitable for improving the hot workability of the Cu-Sn alloy, and 0.8 parts by weight or more and 4.5 parts by weight or less may be more suitable. have. When the total content of Co and Ti exceeds 4.5 parts by weight, the amount of inclusions in the Cu matrix may increase.

Although not limited thereto, according to one embodiment, a value of (Co + Ti) / Sn of 0.03 parts by weight or more is suitable for improving the hot workability of the Cu-Sn alloy, and a value of 0.04 parts by weight or more may be more suitable.

According to another aspect, an article is provided made from a copper-tin alloy capable of hot rolling. Although not limited thereto, the article may be a spring, a connector, a lead frame, or a component for semiconductor packaging.

According to another aspect, i) 4 to 22 parts by weight of Sn, based on 100 parts by weight of the copper alloy; 0 to 1.0 parts by weight of P; 0.1 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and the remainder of Cu and unavoidable impurities; casting a Cu-Sn alloy comprising; and ii) hot-rolling the cast Cu-Sn alloy, wherein Co and Ti are dissolved in Sn segregation, and Co-Ti compounds, Sn-Ti compounds, and Sn-Co compounds at grain boundaries There is provided a method for producing a copper-tin alloy capable of hot rolling, characterized in that it produces one or more selected from.

According to one embodiment, the hot rolling of step ii) is preferably performed at 750 °C to 850 °C. However, performing hot rolling at a high temperature exceeding 850 ° C. is not suitable because there is a risk of cracking in the segregated portion of alloy components and in the portion where the melting point is lowered. If hot rolling is performed at less than 750° C., it may be difficult to hot-roll the structure uniformly.

Although not limited thereto, according to one embodiment, the Co-Ti compound may be at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti, and Sn segregation forms a Co-Ti compound, The hot rolling properties of the alloy can be improved.

Although not limited thereto, according to one embodiment, the Sn-Ti compound may be at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ , and Sn and Ti react to form a copper matrix. It can form stable compounds in When stable compounds are formed at grain boundaries, copper-tin alloys with improved hot workability can be manufactured.

Although not limited thereto, according to one embodiment, the Sn-Co compound may be at least one selected from Co ₃ Sn ₂ and CoSn, and Sn and Co react to form a stable compound in a copper matrix. . When stable compounds are formed at grain boundaries, copper-tin alloys with improved hot workability can be manufactured.

Although not limited thereto, according to one embodiment, the reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy may be suitably greater than 15%, and may be more suitably greater than 20%. When the reduction rate of the cross-sectional area is 15% or less, only the surface layer is drawn, and a difference in structure between the inner and outer layers may occur, and the structure may be destroyed (crashing).

Hereinafter, with reference to the accompanying drawings, a method for manufacturing a copper-tin alloy capable of hot rolling according to the present invention and a copper-tin alloy manufactured thereby will be described in detail.

Example

1. Preparation of Copper-Tin Alloy Added with Ti and Co 1

3A to 3C show a graph of phase change of the alloy according to the amount of titanium added and temperature, a graph of phase change of the alloy according to the amount of Sn added and temperature, and a graph of phase change of the alloy according to the amount of addition of Co and temperature. 3a to 3c, it was confirmed that when Ti and Co are added to the copper-tin alloy, Sn segregation generated at the grain boundary is suppressed or a more stable compound is generated at a position where Sn segregation exists.

Co and Ti are elements that increase stability by reacting with Sn, and make stable compounds within the copper base itself. By making a more stable phase than Sn segregation or forming a stable compound at the grain boundary, Sn-doped copper with improved hot workability can be manufactured.

Table 1 below shows the radii, melting points, densities, and structures of Sn, Co, Ti, and Cu, respectively.

atom Sn(50) Co(27) Ti(22) Cu(29) Radius (nm) 0.145 0.135 0.140 0.135 Melting point (℃) 232 1595 1668 1085 Density (g cm ^-3 ) 7.29 or 5.79 8.9 4.51 8.96 rescue Diamond or BCC tetragonal HCP HCP FCC

According to FIG. 3, the Sn-Ti compound has Sn ₃ Ti ₂ , βSn ₅ Ti ₆ , and Sn ₃ Ti ₅ at 1490 ° C or higher, and the Sn-Co compound has βCo ₃ Sn ₂ and CoSn at 1209 ° C or higher. , Co-Ti compounds can be seen that CoTi ₂ , CoTi, and Co ₂ Ti compounds exist at 1058 ° C or higher.

2. Preparation of Copper-Tin Alloy Added with Ti and Co 2

Hereinafter, the present invention will be described in more detail through specific examples and comparative examples of the present invention, and evaluation results of their characteristics.

The phase fraction according to temperature and equilibrium, equilibrium-cooling, and Sheil Gulliver-cooling is shown in FIGS. 4 and 5 for the Cu—Sn alloy having the composition shown in Table 2 below.

Cu Sn P Co Ti Alloy A wt% Bal. 8 0.1 - - at% Bal. 4.443 - - Alloy B wt% Bal. 8 0.1 0.45 0.36 at% Bal. 4.443 0.213 0.503 0.495

Figure 4 is a graph showing the phase fraction according to the temperature and equilibrium, equilibrium-cooling, and Sheil Gulliver-cooling of the Cu-8Sn-0.1P alloy (Alloy A). According to FIG. 4, Cu ₃ P and Cu ₃ Sn compounds were observed.

5 shows the phase fraction according to the temperature and equilibrium, equilibrium-cooling, and Sheil Gulliver-cooling of the Cu-8Sn-0.1P-0.45Co-0.36Ti alloy (Alloy B). According to FIG. 5, Cu ₃ P, Cu ₃ Sn, Ti ₆ Sn ₅ , CoTi, and Co ₂ Ti compounds were observed.

Therefore, it can be confirmed that various compounds are produced when Co and Ti are added to Sn-added copper. However, during the actual casting process, it is difficult to reach phase equilibrium, so various phases are created. For example, a Sn-Ti compound, a Sn-Co compound, a Co-Ti compound, and a Co-Ti-Sn compound are produced.

Table 3 shows the content of the components of Comparative Example 1, Comparative Example 2 and Examples 1 to 15, values of Co+Ti, (Co+Ti)/Sn, Ti/Co parameters, hot rolling temperature, and hot rolling It shows the rolling properties.

Casting grains of the alloys of Comparative Example 1 and Examples 1 to 4 are shown in FIG. 6 .

According to FIG. 6, Examples 2 (Alloy 3) and Example 4 (Alloy 5) having a total amount of Co and Ti of 1.33 wt% and 3.01 wt%, respectively, have a total amount of Co and Ti of 0 wt%, 0.35 wt%, and Compared to Comparative Example 1 and Examples 1 and 3 (Alloys 1, 2, and 4), which are 0.87 wt%, it can be seen that the cast crystal grains are refined.

Therefore, it can be confirmed that the cast crystal grains are refined as the total content of Co and Ti increases.

For the alloys of Comparative Example 1 and Examples 1 to 4, the cross-sectional area reduction rate and the appearance of the alloy according to the phosphorus (P), cobalt (Co), and titanium (Ti) contents of the copper-tin alloy are shown in FIG. 7 . According to FIG. 7, in the case of Comparative Example 1 (Alloy 1 (Cu-8.48Sn-0.18P)) not containing Co and Ti, the cross-sectional area reduction rate was 15%, and crashing occurred immediately after hot rolling Hot rolling was impossible. In the case of Examples 1 to 4 (Alloy 2 to Alloy 5) in which Co and Ti were simultaneously added, hot rolling at 850 ° C was possible. It was confirmed that hot rolling is possible from 0.34wt% of Co and 0.01wt% of Ti.

Figure 8 shows the cross-sectional area reduction rate and the appearance of the alloys according to the contents of phosphorus (P), cobalt (Co), and titanium (Ti) for the alloys of Comparative Example 2 and Examples 5 to 9.

According to FIG. 8, in the case of Comparative Example 2 (Alloy 6 (Cu-7.97Sn-0.12P)) not containing Co and Ti, the cross-sectional area reduction rate was 15%, and crashing occurred immediately after hot rolling Hot rolling was impossible. In the case of Examples 5 to 9 (Alloy 7 to Alloy 11) in which Co and Ti were simultaneously added, hot rolling at 850 ° C was possible. When Co and Ti were simultaneously added, hot rolling was possible, and hot rolling was also possible in the case of Examples 7 to 9 (Alloy 9 to Alloy 11) having a P content of 0 wt%. Therefore, when P is not included and Co and Ti are included at the same time, it can be confirmed that hot rolling at 850 ° C. is possible.

9 is a view showing inclusions in the alloy according to the contents of phosphorus (P), cobalt (Co), and titanium (Ti) in the copper-tin alloy. According to FIG. 9, it can be seen that the amount of inclusions increases as the contents of Co and Ti increase.

Figure 10 shows the composition profile of the Sn-rich and deficient parts of Comparative Example 2 (Alloy 6 (Cu-7.97Sn-0.12P alloy)). It can be confirmed that P exists as an intermetallic compound in Sn segregation.

11 shows the composition profile of the Sn segregation part of Example 5 (Alloy 7 (Cu-8.21Sn-0.34P-0.45Co-0.36Ti alloy)). It can be confirmed that Co and Ti are dissolved in Sn segregation, and present as Co-Ti compounds (CoTi ₂ , CoTi, Co ₂ Ti compounds) at the grain interface.

12 shows the composition profile of the Sn segregation part of Example 6 (Alloy 8 (Cu-8Sn-0.1P-1Co-0.5Ti alloy)). It can be confirmed that Co and Ti are dissolved in Sn segregation, and present as Co-Ti compounds (CoTi ₂ , CoTi, Co ₂ Ti compounds) at the grain interface.

13 shows the composition profile of the Sn segregation part of Example 7 (Alloy 9 (Cu-8Sn-1.51Co-0.91Ti alloy)). It can be confirmed that Co and Ti are dissolved in Sn segregation, and present as Co-Ti compounds (CoTi ₂ , CoTi, Co ₂ Ti compounds) at the grain interface.

14 shows the composition profile of the Sn segregation portion of Example 8 (Alloy 10 (Cu-8Sn-2.78Co-1.76Ti alloy)). It can be confirmed that Co and Ti are dissolved in Sn segregation or present as Co-Ti compounds (CoTi ₂ , CoTi, Co ₂ Ti compounds) at grain boundaries.

15 shows the composition profile of the Sn segregation portion of Example 9 (Alloy 11 (Cu-8Sn-2.31Co-1.38Ti alloy)). It can be confirmed that Co and Ti are dissolved in Sn segregation or exist as Sn-Ti compounds (Sn ₃ Ti ₂ , βSn ₅ Ti ₆ , Sn ₃ Ti ₅ ) at grain boundaries.

According to FIGS. 11 to 15, it was shown that Co and Ti were dissolved in Sn segregation or reacted with Sn to form a stable compound. Therefore, by forming a stable compound at the grain boundary, a Sn-added copper alloy with improved hot workability can be manufactured.

Figure 16b shows the cross-sectional area reduction rate and the appearance of the alloy according to the content of phosphorus (P), cobalt (Co), and titanium (Ti) for the Cu—Sn alloys of Examples 10 to 15.

16a and 16b, when the Cu-Sn alloy having the composition of Table 3 was hot-rolled at 750 ° C to 850 ° C, the cross-sectional area reduction rate of Comparative Example 1 (Alloy 1 (Cu-8.48Sn-0.18P)) 15%, while Example 10 (Alloy 12) and Example 11 (Alloy 13) can confirm that the cross-sectional area reduction rate has increased to 20%, and the cross-sectional area reduction rate of Example 15 (Alloy 17) has also increased to 21%. can In Examples 12 to 14 (Alloy 14 to Alloy 16), it was found that the cross-sectional area reduction rate increased dramatically to 50%, 49%, and 48%, respectively.

Although not limited thereto, according to one embodiment, the reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy may be suitably greater than 15%, and may be suitably greater than 20%. When the reduction rate of the cross-sectional area is 15% or less, only the surface layer is drawn, and a difference in structure between the inner and outer layers may occur, and the structure may be destroyed (crashing).

When P, Co, and Ti are simultaneously added to the copper-tin alloy, hot rolling is possible even at a low temperature of 750 ° C., and hot rolling is possible when Sn is included in 4 wt% to 22 wt%.

In the above, an embodiment of the present invention has been described, but those skilled in the art can add, change, delete, or add components within the scope not departing from the spirit of the present invention described in the claims. Various modifications and changes may be made to the present invention by addition or the like, which will also be included within the scope of the present invention.

Claims (16)

For 100 parts by weight of copper alloy,
4 to 22 parts by weight of Sn;
0.1 to 3.0 parts by weight of Co;
0.01 to 2.0 parts by weight of Ti; and
A Cu-Sn alloy consisting of Cu and the balance of unavoidable impurities; a copper-tin alloy capable of being hot rolled. For 100 parts by weight of copper alloy,
4 to 22 parts by weight of Sn;
0 to 1.0 parts by weight of P;
0.45 to 3.0 parts by weight of Co;
0.01 to 2.0 parts by weight of Ti; and
A Cu-Sn alloy consisting of Cu and the balance of unavoidable impurities;
Co and Ti are dissolved in Sn segregation, and a Co-Ti compound is included at the grain boundary,
The Co-Ti compound is a copper-tin alloy capable of hot rolling, characterized in that at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti. According to claim 1 or 2,
A copper-tin alloy capable of hot rolling, characterized in that Co and Ti are dissolved in Sn segregation, and at least one selected from Sn-Ti compounds and Sn-Co compounds. According to claim 3,
The Sn-Ti compound is at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ , characterized in that, a copper-tin alloy capable of hot rolling. According to claim 3,
The Sn-Co compound is a copper-tin alloy capable of hot rolling, characterized in that at least one selected from Co ₃ Sn ₂ and CoSn. According to claim 1 or 2,
Characterized in that the reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy is greater than 15%, a copper-tin alloy capable of hot rolling. According to claim 1 or 2,
A copper-tin alloy capable of hot rolling, wherein the sum of the Co and Ti contents is 0.3 parts by weight or more. According to claim 1 or 2,
A copper-tin alloy capable of being hot rolled, wherein the value of (Co + Ti)/Sn is 0.03 parts by weight or more. An article made of the hot-rollable copper-tin alloy according to claim 1 or 2, which is a spring, a connector, a lead frame, or a component for semiconductor packaging. i) 4 to 22 parts by weight of Sn, based on 100 parts by weight of copper alloy; 0.1 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and Cu and the balance of unavoidable impurities; casting a Cu-Sn alloy comprising; and
ii) hot-rolling the cast Cu-Sn alloy; including, hot-rollable copper-tin alloy manufacturing method. i) 4 to 22 parts by weight of Sn, based on 100 parts by weight of copper alloy; 0 to 1.0 parts by weight of P; 0.45 to 3.0 parts by weight of Co; 0.01 to 2.0 parts by weight of Ti; and Cu and the balance of unavoidable impurities; casting a Cu-Sn alloy comprising; and
ii) hot-rolling the cast Cu—Sn alloy;
Co and Ti are dissolved in Sn segregation, and a Co-Ti compound is generated at the grain interface, and the Co-Ti compound is at least one selected from CoTi ₂ , CoTi, and Co ₂ Ti. Characterized in that, Method for producing a copper-tin alloy capable of hot rolling. According to claim 10 or 11,
The method for producing a copper-tin alloy capable of hot rolling, characterized in that the hot rolling of step ii) is performed at 750 ° C to 850 ° C. According to claim 10 or 11,
A method for producing a copper-tin alloy capable of hot rolling, characterized in that Co and Ti are dissolved in Sn segregation and at least one selected from Sn-Ti compounds and Sn-Co compounds is produced. According to claim 13,
The Sn-Ti compound is at least one selected from Sn ₃ Ti ₂ , Sn ₅ Ti ₆ , and Sn ₃ Ti ₅ Method for producing a copper-tin alloy capable of hot rolling. According to claim 13,
The Sn-Co compound is a method for producing a copper-tin alloy capable of hot rolling, characterized in that at least one selected from Co ₃ Sn ₂ and CoSn. According to claim 10 or 11,
The method for producing a copper-tin alloy capable of hot rolling, characterized in that the reduction rate of the cross-sectional area after hot rolling of the copper-tin alloy is greater than 15%.

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