KR900006105B1 - Cu-alloy and method for cu-alloy sheet - Google Patents

Abstract

Cu alloy consists of (in wt.%) 13.0-25.0 Zn, 2.0-4.0 Al, 0.3-5.0 Ni, 0.1-3.0 Si, 0.1-3.0 B, 0.5-3.0 Ti and balance Cu. The copper alloy has high strength, elasticity and heat resistance. The copper alloy sheet is made by hot rolling at 850-1000 deg.C, first cold rolling to 40-60%, annealing at 500-700 deg. C for 1-5 hrs., second cold rolling to 40-60%, annealing at 500-700 deg.C for 1-5 hrs., third cold rolling to 40-60%, annealing at 500-700 deg.C for 1-5 hrs., finish cold rolling to 40-60%, and low temperature annealing at 200-400 deg.C for 1-5 hrs.

Description

High strength, high elasticity, high heat resistance, manufacturing method of copper alloy and copper alloy plate

1 is a change in the tensile strength according to the annealing temperature in the alloy of the present invention.

2 is a heat resistance resistance comparison diagram of the present invention alloy and the existing copper alloy.

The present invention relates to a method for manufacturing high strength, high elasticity, high heat resistant copper alloy and copper alloy plate, and more specifically, for connectors, relays, switches, electrical, electronics in the fields of electrical and electronic communication The present invention relates to a manufacturing method of copper alloy and copper alloy plate used in electric springs, and furthermore, used in high-tech industries such as automobiles and aerospace industries.

In addition, the present invention fully considered not only did not use high-priced elements Sn and Be in order to lower the price of high strength, high elasticity and high heat resistant copper alloy, but also simplified the manufacturing process, and furthermore, without using special equipment. The characteristics of the existing high strength, high elasticity, high heat-resistant copper alloy is equivalent to, or in some properties even better properties to maintain.

Typical materials of high strength, high elasticity and high heat resistant copper alloys include phosphor bronze and beryllium copper, which are mainly used for electric and electronic parts. Such phosphor bronze contains 5-8% Sn, which is not only expensive but also a manufacturing process. It was difficult to compare with this general brass and had the disadvantage of low thermal softening resistance at which the material softened at about 500 ° C. Also, in the case of beryllium copper, it must contain extremely expensive beryllium, which is also expensive. In addition to being expensive, beryllium is an extremely toxic element, so it is necessary to have special equipment for manufacturing as well as difficulty in dissolution.

Therefore, phosphor bronze and beryllium copper are expensive, and the manufacturing process is difficult compared to general brass. Therefore, phosphor bronze and beryllium copper have the same strength and spring characteristics, and the manufacturing process is simple, and the high-strength, high elasticity, and high heat resistant copper alloy is inexpensive. New metals are required in the field of electrical and electronic component materials.

The present invention is to solve the above problems, the present invention is roughly divided into two forms, first, the spring having a strength (78kg / ㎜) corresponding to the spring hard temper of phosphor bronze The invention is an invention of an alloy having excellent heat resistance and excellent heat resistance, and secondly, to develop a high elastic alloy having a strength equivalent to that of a mill hardened temper (107 kg / mm 2 or more) of copper beryllium.

The alloy composition of the present invention is, firstly, to replace the spring hard temper of phosphor bronze, a small amount of Si, B and Ti in a Cu-Zn-Al-Ni-based alloy separately or in combination Secondly, as an alloy to replace the mill hardened temper of copper beryllium, a small amount of Si, B, and Ti are simultaneously added to the Cu-Zn-Al-Ni-based alloy and precipitate hardened. In this case, the mechanical properties are greatly improved.

On the other hand, in the alloy of the present invention, not only Si, B and Ti are added to improve mechanical properties, but also reinforcing mechanisms such as cold working and grain refinement have been applied.

That is, after melt casting, the casting ingot is homogenized and heat-treated, followed by hot rolling, cold rolling, annealing, cold rolling, and annealing, thereby reducing the thickness to further increase the strength of the final material, and at the same time, to refine the grain. In addition to increasing the strength, the ductility was also increased.

In the alloy of the present invention, the alloying element composition range is (% by weight), Cu-Zn (13.0 ~ 25.0%) -Al (2.0 ~ 4.0%) -Ni (0.3 ~ 5.0%) -Si (0.1 ~ 3.0%)- B (0.1 ~ 3.0%) -Ti (0.5 ~ 3.0%), Cu-Zn (13.0 ~ 25.0%) -Al (2.0 ~ 4.0%) -Ni (0.3 ~ 5.0%) -Si (0.1 ~ 3.0% ) -B (0.1-3.0%) and Ti (0.5-3.0%) are added separately or together. The reason why the range of addition of each element is set as described above is as follows.

Zn: 13.0 ~ 25.0%

When Zn is 25% or more, a large amount of beta (β) phase of the brittle phenomena of BCC (body centered cubic tissue) is generated, and the workability and elongation are decreased. Since strength falls, Zn is preferably set to 13.0 to 25.0%.

Al: 2.0 ~ 4.0%

When Al is 8.0% or more, a large amount of beta (β) phase is generated, and workability and elongation are lowered, and when it is 1.5% or less, strength is lowered. Preferably, Al is set to 2.0 to 4.0%.

Ni: 0.3 ~ 5.0%

Ni may be employed in Cu up to 30%, but a large amount of addition is economically disadvantageous, and it becomes difficult to obtain a complex structure of alpha (α) and beta (β). α) and beta (β) is a complex structure), if less than 0.1%, it is difficult to produce the precipitates necessary for precipitation strengthening NiSi and Ni ₂ Si and the like is preferably set Ni to 0.3 to 5.0%.

Si: 0.1 ~ 3.0%

Si is an element required for solid solution strengthening and formation of Ni ₂ Si precipitates. When the content is 5.0% or more, the strength is increased, but the workability and elongation are lowered. Therefore, Si is preferably 0.1 to 3.0%.

B: 0.1-3.0%

B causes precipitation strengthening by the formation of precipitates such as NiB and TiB, and at the same time induces grain refinement. When it is 3.0% or more, the strength is increased so much that workability and elongation are deteriorated. I can't do it.

Therefore, B is preferably 0.1 to 3.0%.

Ti: 0.5 ~ 3.0%

Ti increases the strength by forming precipitates such as TiB, TiSi, CuTi, etc. in the alloy. However, when Ti is 4.0% or more, the strength is too high to degrade workability and elongation. will be.

The alloys in the above range was subjected to the manufacturing process of melting, casting, hot rolling, cold rolling, annealing, the main process is as follows.

One). The melting method is charged with Cu now and completely dissolved, and then the temperature is raised, Ni is added, the temperature is lowered, and then Si is added. Then, a Cu-B master alloy and a Cu-Ti master alloy are sequentially added, and Al and Zn are added. After melting, casting and casting were performed.

2). Hot rolling was performed at 850 ℃ ~ 1000 ℃ to reduce thickness by hot rolling. The formation of precipitates after hot rolling has an important influence on improving the overall strength, spring resistance and heat resistance. If the hot rolling temperature is lower than 850 ℃, it causes the formation of precipitates and causes cracks during rolling. The results showed that it affects the heterogeneous tissue state and decreased precipitate formation.

3). After the primary cold rolling was rolled at a reduction ratio of 40 to 60%, annealing was performed at 500 ° C. to 700 ° C. for 1 to 5 hours to improve spring properties and homogenize the structure.

4). After the secondary cold rolling was rolled at a reduction ratio of 40 to 60%, annealing was performed at 500 ° C to 700 ° C for 1 to 5 hours.

5). After the third cold rolling was rolled at a reduction ratio of 40 to 60%, annealing was performed at 500 ° C to 700 ° C for 1 to 5 hours.

6). The final cold rolling was rolled at a reduction ratio of 40 to 60%, followed by low temperature annealing at 500 ° C to 700 ° C for 1 to 5 hours.

The reduction ratio of cold rolling is closely related to the annealing temperature, and the high reduction ratio of 60% or more in cold rolling increases anisotropy and increases the possibility of cracking, and when it is less than 40%, it is difficult to satisfy the required strength.

In addition, when the annealing temperature exceeds 700 ℃ affects the decrease in strength and the weakening of the tissue due to grain growth, and less than 500 ℃ to the cold rolling properties to harm the soft rolling.

In addition, when the annealing time exceeds 5 hours, it affects the strength reduction and heat resistance improvement due to grain growth, and when less than 1 hour, the formation of unstable precipitates is shown.

In addition, the most suitable final annealing temperature and time for improving spring property and decreasing directionality were shown as 1 ~ 5 hours at 200 ℃ ~ 400 ℃.

The present invention was carried out by the above method as follows.

Example 1

TABLE 1

The alloys of the two compositions were cast at 1300 ° C. after induction melting in an atmospheric pressure reducing atmosphere, and the ingots were first cold rolled at a reduction ratio of 40% after hot rolling at 900 ° C., and then annealed at 600 ° C. for 3 hours.

After reducing the thickness to 60% by 3rd cold rolling, annealing was performed at 600 ℃ and finally rolled to produce a final cold rolled sheet of 0.3mm.The mechanical properties of the finished cold rolled sheet before cold annealing and the finished cold rolled sheet at 320 ℃ The physical properties of the low temperature annealing are shown in Table 2.

TABLE 2

After annealing, it can be seen that the elastic limit, that is, the spring property, has been increased by about 2 times.The No. 2 alloy containing Si is manufactured with the same thickness (0.3mm) by the same hot and cold rolling process than No.1 alloy. Ten percent higher in tensile strength and 16 percent higher in elastic limit.

Example 2

TABLE 3

After dissolving the alloy No. 3 above in an atmospheric reducing atmosphere, Si and a Cu—B mother alloy were added thereto. The molten product was cast at 1350 ° C. and then heated to 950 ° C. to hot roll the thickness to 8 mm, and the hot rolled plate was cold annealed to 3 to 4 mm at 1,550 ° C. and then annealed at 550 ° C., and the second to 50% reduction ratio. After cold rolling, 2 mm was annealed at 550 ° C., and thirdly cold rolled to 1 mm thickness was annealed at 650 ° C.

Subsequently, after the final cold rolling to 0.5mm, the final rolled sheet was obtained by low temperature annealing at 320 ° C. for about 1 hour. Thus, the physical properties of the final cold rolled sheet before low temperature annealing and the rolled sheet at low temperature at 320 ° C. for 1 hour (mechanical properties) Is shown in Table 4.

TABLE 4

It was shown that when 0.2% of B was added to No.1 composition, there was no change in tensile strength, but the elastic limit was increased.

Example 3

TABLE 5

The alloy Nos. 4 to 7 were induced and dissolved in an atmospheric reducing atmosphere, B and Ti were added using a master alloy of Cu-B and Cu-Ti, and Si was added using pure Si. When the temperature of the molten metal reached 1300 ℃, the ingot was cast to make an ingot.The ingot was heated to 980 ℃ and hot rolled to 7 ~ 9mm, and the hot rolled material was first cold rolled at 50% reduction rate to have a thickness of the plate. After 3 to 4mm and annealed at 500 ~ 700 ℃.

Subsequently, the plate was cold-cold at 50% reduction rate to 2 mm and then annealed at 500 to 700 ° C. In addition, after the third cold rolling to 1mm thickness again annealing at 500 ~ 700 ℃, the final cold rolling to 0.5mm and then low temperature annealing at 200 ~ 400 ℃ for 1 hour. On the other hand, Table 6 shows the mechanical properties of the final cold rolled sheet before low temperature annealing and the rolled sheet subjected to low temperature annealing at 320 ° C. for 1 hour.

TABLE 6

As in the present embodiment, the tensile strength and the elastic limit were greatly increased in No. 6, in which Si, B, and Ti were simultaneously added to Cu-Zn-Al-Ni, which is the No. 1 alloy.

The strength after low temperature annealing of No. 6 is comparable with the strength value after precipitation hardening of copper beryllium, and the high strength of No. 6 is due to Ti (2.78%) and B (2.74%).

The strength of the alloy No. 7 (114kg / mm 2) was also higher than that of the mill hardened temper of beryllium copper, and the elastic limit was also high.

Example 4

TABLE 7

The Nos. 8, 9 and 10 alloys were inductively dissolved in an atmospheric reducing atmosphere, B and Ti were added using Cu-B and Cu-Ti master alloys, and Si was added using pure Si.

The ingot was made by casting when the temperature of the molten metal was 1300 ° C.

Hot rolled at 900 ℃ to make 8mm, first cold rolled to 4mm thickness, then annealed at 600 ℃, second cold rolled to 2mm, then annealed again at 600 ℃, third cold rolled to 1mm, 600 ℃ After annealing at, the final cold rolled to 0.5mm.

The final rolled material was annealed at 350 ° C. at low temperature, and the mechanical properties before and after low temperature annealing of the final rolled sheet are shown in Table 8.

TABLE 8

As shown in Table 8, alloy No. 10 in which the alloy composition is not added with Si and Ti is lowered in tensile strength, and alloy No. 9 with simultaneous addition of Ti and Si and alloy No. 8 with Si and B added The mechanical properties were excellent.

The tensile strengths of Nos. 8 and 9 are the tensile strengths corresponding to the spring hard temper of phosphor bronze.

Example 5

TABLE 9

The composition alloy 11 was dissolved in an atmospheric reducing atmosphere, and Ti was added using a mother alloy of Cu-Ti.

The molten material was cast at 1350 ° C. and then heated to 950 ° C. to hot roll the thickness of 8 mm, and the hot rolled plate was cold rolled to 3 to 4 mm at the first cold annealing at 550 ° C., followed by secondary cold at 50% reduction. After rolling to 2mm, annealing was carried out at 550 ° C., followed by cold rolling 3 times to 1mm thickness, and annealing at 650 ° C.

After final cold rolling to 0.5mm, the final rolled plate was obtained by low temperature annealing at 320 ℃ for about 1 hour, and the physical properties (mechanical properties) of the final cold rolled plate before low temperature annealing and the rolled sheet at low temperature at 320 ℃ for 1 hour 10 is shown.

TABLE 10

The mechanical properties of alloy No. 11 were found to be improved than that of phosphor bronze.

Example 6

TABLE 11

The composition alloy No. 12 was dissolved in an atmospheric reducing atmosphere, and B and Ti were added using a Cu-B and a Cu-Ti master alloy.

The molten metal was cast at a temperature of 1300 ° C. to make an ingot, and hot rolled at 900 ° C. to 8 mm, followed by primary cold rolling to a thickness of 4 mm, followed by annealing at 600 ° C.

After the second cold rolling to 2mm and annealing again at 600 ℃, the third cold rolling to 1mm and annealing at 600 ℃, the final cold rolling to 0.5mm.

The final rolled material was cold-annealed at 350 ° C., and the mechanical properties before and after low-temperature annealing of the final rolled sheet are shown in Table 12.

TABLE 12

As shown in Table 12, the mechanical properties of Alloy No. 11 can be seen to be excellent by simultaneous addition of Ti and B.

In total from Examples 1 to 6, the No. 2 alloy containing 0.3% Si in the No. 1 alloy Cu-Zn-Al-Ni composition of Example 1 was 10% at tensile strength and 16% at elastic limit. You can see that increased.

The alloy of No. 3 of Example 2 added B by 0.2% to the Cu-Zn-Al-Ni composition, and showed that the tensile strength was comparable with the No. 2 alloy and the elastic limit was slightly increased.

The tensile strengths of No. 2 and No. 3 correspond to Spring Hard Temper (68 ~ 79kg / mm2) of phosphor bronze, which has much better elongation and limit of impact.

Alloy No. 4, No. 5, No. 6, and No. 7 in Example 3 were obtained by adding a small amount of Si, B, and Ti to a Cu-Zn-Al-Ni-based alloy, which added only Si and B. The mechanical properties were much better than those of No. 2 and No. 3 alloys. Alloy No. 6 and No. 7 showed the same tensile strength as beryllium copper, and the elastic limit was 90kg /. It exceeds 2mm2.

In conclusion, in the present invention, the alloys except alloys No. 1 and No. 10 can be replaced with phosphor bronze and beryllium copper, and Nos. 2 to 5, No. 8, No. 9, No. 11, and No. 12 Phosphor Bronze, No. 6 and No. 7 replace beryllium copper at low cost with equivalent mechanical properties or more.

Example 7

Thermal Softening Resistance Test In order to test the thermal softening resistance of the alloy of the present invention, cold rolled sheet materials of alloys No. 1, No. 2, and No. 7 before final annealing were used. After annealing at temperatures of 400, 500, 600, 650 ° C. for about 1 hour, a tensile test was performed at room temperature, and the change in tensile strength was measured according to the annealing temperature. The results are shown in FIG.

As shown in FIG. 1, the No. 2 and No. 7 alloys in which Si, B, Ti, etc. were added alone or together were much higher than the No. 1 alloy of Cu-Zn-Al-Ni alone. .

FIG. 2 compares the alloys of the present invention with general brass (Cu 70-Zn 30) phosphorous beryllium copper and the thermal softening resistance. As shown in FIG. 1, alloys No. 2 and No. 7 of the present invention are more than phosphor bronze. It was excellent in heat resistance and almost equal to beryllium copper.

The thermal softening resistance is determined according to the size of the grains. In order to compare the thermal softening resistance, after annealing several alloys at 500 ° C, 600 ° C, and 650 ° C for 1 hour, the grain growth was measured. In the absence of Si, B, Ti, grains grew coarsely, and the alloys added with Si, B, Ti were observed to have a grain size of 0.01 mm or less even at 650 ° C. Addition has been shown to reduce the grain size, thereby making it excellent in thermal softening resistance.

The physical properties and prices of the alloys and conventional alloys of the present invention are summarized in Table 13 below.

TABLE 13

As shown in Table 13, the alloy of the present invention is superior to phosphor bronze in physical properties, is almost similar to beryllium copper, and is much cheaper than phosphor bronze and beryllium copper in terms of price, so that the alloy of the present invention has high strength in electric, electronic and communication fields. It is a material for major parts in the field where high elasticity and high heat resistance are required, and it is a substitute material of expensive phosphor bronze and beryllium copper for spring, which is expensive among existing alloys. It can be used.

Claims (7)

The chemical composition of the alloy is Zn 13.0 ~ 25.0%, Al 2.0 ~ 4.0%, Ni 0.3 ~ 5.0%, Si 0.1 ~ 3.0%, B 0.1 ~ 3.0%, Ti 0.5 ~ 3.0%, and the rest is composed of Cu High strength, high elasticity, high heat resistant copper alloy. High strength, high elasticity, high heat resistance, characterized in that the chemical composition of the alloy is Zn 13.0 ~ 25.0%, Al 2.0 ~ 4.0%, Ni 0.3 ~ 5.0%, Si 0.1 ~ 3.0%, and the remainder is composed of Cu Copper alloy. High strength, high modulus, high heat resistant copper alloy characterized by adding 0.5 to 3.0% of Ti to the chemical composition of alloys of Zn 13.0 ~ 25.0%, Al 2.0 ~ 4.0%, Ni 0.3 ~ 5.0%, and the remainder composed of Cu. . The alloy has a chemical composition of Zn 13.0-25.0%, Al 2.0-4.0%, Ni 0.3-5.0%, and Si 0.1-3.0%, B 0.1-3.0% is added, and the remainder is composed of Cu. , High elasticity, high heat resistant copper alloy. The alloy has a chemical composition of Zn 13.0-25.0%, Al 2.0-4.0%, Ni 0.3-5.0%, and Si 0.1-3.0%, Ti 0.5-3.0%, and the remainder is composed of Cu. , High elasticity, high heat resistant copper alloy. It is characterized in that the chemical composition of the alloy is Zn 13.0-25.0%, Al 2.0-4.0%, Ni 0.3-5.0%, B 0.1-3.0%, Ti 0.5-3.0%, and the remainder is composed of Cu. High strength, high elasticity, high heat resistant copper alloy. After melting and casting the copper alloy of the composition of the present invention, 1) hot rolling at 850 ~ 1,000 ℃, 2) primary cold rolling at a reduction ratio of 40 ~ 60%, 3) annealing for 1 to 5 hours at 500 ~ 700 ℃, 4) 2nd cold rolling at 40 ~ 60% reduction rate, 5) Annealing 1 ~ 5 hours at 500 ~ 700 ℃, 6) 3rd cold rolling at 40 ~ 60% reduction rate, 7) 1 ~ at 500 ~ 700 ℃ 5 hours annealing, 8) final cold rolling at a reduction ratio of 40 to 60%, 9) low temperature annealing at 200 to 400 ° C. for 1 to 5 hours, to produce a high strength, high elasticity and high heat resistant copper alloy sheet.

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