JPS6234824B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a copper alloy with excellent hot workability, and more particularly, to a copper alloy with excellent hot rollability. [Prior Art] Generally, extremely high reliability is required for spring materials such as terminals and connectors used in aircraft and large computers, etc., and beryllium copper has traditionally been used in these fields. ing. In addition, as electrical and electronic devices have become lighter, thinner, and smaller in recent years, the spring materials used in these devices are also required to be thinner. Demand for high-strength copper alloys such as beryllium copper is increasing. However, Be itself is expensive;
In addition, since Be and oxides containing Be are harmful to the human body, various safety and hygiene protection measures must be taken when producing copper alloys containing Be. The materials themselves are becoming more expensive. Therefore, there is a need for a high-strength copper alloy that has no problems in terms of safety and hygiene, is an inexpensive material, and has properties comparable to beryllium copper. [Problems to be Solved by the Invention] As explained above, the present invention solves the problem that although beryllium copper, which is used as a spring material for aircraft, large computers, etc., is reliable,
In view of the problems of safety, hygiene, and high cost due to the use of Be, the inventor of the present invention has conducted intensive research and found that it does not contain elements harmful to the human body such as Be, and It is advantageous in price compared to beryllium copper, and the inclusion of trace elements improves hot workability, especially
They developed a copper alloy with excellent hot workability, which is a structurally homogeneous material that has excellent hot rolling properties, and sufficient diffusion of the contained components occurs through hot rolling. [Means for solving the problems] The copper alloy with excellent hot workability according to the present invention includes: (1) Ni 2 to 30 wt%, Sn 3 to 9 wt%, Co 0.01 to 1.0 wt%;
%, Cr0.002~0.1wt%, and the remainder essentially consists of Cu, the first invention is a copper alloy with excellent hot workability, (2) Ni2~30wt%, Sn3~9wt%, Co0.01~1.0wt
%, Cr0.002~0.1wt%, and further contains one or two selected from Mg0.001~0.01wt%, Si0.005~0.2wt%, and the remainder is essentially Cu. This invention consists of two inventions, the second invention being a copper alloy with excellent hot workability characterized by comprising: The copper alloy with excellent hot workability according to the present invention will be described in detail below. Generally, in a certain composition range, Cu-Ni-Sn alloys undergo a phase separation phenomenon called spinodal decomposition by adopting an optimal manufacturing process, and α
It is known that the phase separates into two phases (α+α'). This phase separation significantly improves strength properties such as tensile strength and spring limit value. This will be explained in detail. That is,
Ni8.74wt%, Sn5.39wt%, Co0.054wt%,
A copper alloy consisting essentially of Cr0.039wt%, Si0.007wt%, Mg0.002wt%, the balance being Cu, is melted and then cast to form an ingot, and the cast structure is broken by hot rolling and cold rolling. After heating the material to 750°C for 1 minute, it is rapidly cooled in water to form the α phase. This material was cold rolled with a reduction in area of 30%, and further low-temperature annealed at 400°C for 1 hour. This low-temperature annealing causes spinodal decomposition and significantly strengthens the material, resulting in a tensile strength of 44.4 Kgf/mm ² compared to the material without low-temperature annealing.
The spring limit value shows an increase of 44.3Kgf/ ^mm2 . However, C72700 (Cu-
9wt%Ni-6wt%Sn) is known, but when ingots are formed in the air without containing Co and Cr at the same time, fine cracks occur on the wide and narrow surfaces during hot rolling. The reason for this is that the grain boundaries become brittle at high temperatures due to the segregation of Sn or Sn compounds at the grain boundaries.
Therefore, C72700 alloy is formed into ingots by horizontal continuous casting, and after homogenization treatment, it is processed into thin plates through a process of repeating cold rolling and intermediate annealing. but,
This manufacturing process is more expensive than the process of hot rolling an ingot formed by vertical continuous casting and then processing it into a thin plate by repeating cold rolling and intermediate annealing. Usage becomes limited. Furthermore, in the process of repeating cold rolling and intermediate annealing without hot rolling, a homogeneous structure cannot be obtained in the final product, resulting in variations in composition depending on location, and increased anisotropy of the material. There's a problem. The present invention includes the above-described Cu-Ni-Sn alloy containing trace amounts of both Co and Cr to form a hot-rollable ingot in an atmospheric atmosphere. By doing so, the process can be shortened compared to the method of cold rolling an ingot by horizontal casting, and by hot rolling, a thin plate with a uniform structure in which the contained components are sufficiently diffused can be manufactured. becomes possible. The components and component ratios of the copper alloy with excellent hot workability according to the present invention will be explained. Ni is an element necessary to impart strength,
If the content is less than 2 wt%, sufficient strength cannot be obtained, and if the content exceeds 30 wt%, work hardening increases, which is disadvantageous from the viewpoint of productivity. Therefore, the Ni content is set to 2 to 30 wt%. Like Ni, Sn is an element that imparts strength.
If the content is less than 3wt%, high strength comparable to beryllium copper cannot be obtained, and if the content exceeds 9wt%, hot rolling cracking cannot be suppressed even if both Co and Cr components are included. becomes impossible. Therefore, the Sn content is set to 3 to 9 wt%. Co is an element that improves hot workability; if the content is less than 0.01wt%, hot workability will not be improved regardless of the Cr content, and if the content exceeds 1.0wt%, the hot workability will not be improved. Compared to a Co content in the range of 1.0 wt%, hot workability is not improved any further, and inclusion of a large amount is wasteful. Therefore, the Co content is
The content should be 0.01-1.0wt%. Cr is an element that imparts the effect of improving hot workability, and when the content is less than 0.002wt%, Co is 0.01 to 1.0wt%.
If the content exceeds 0.1wt%, sufficient hot workability cannot be obtained, and if the content exceeds 0.1wt%, the flowability of the molten metal deteriorates, causing problems with the surface properties of the ingot. occurs, making it impossible to obtain a sound ingot.
Therefore, the Cr content is set to 0.002 to 0.1 wt%. By containing both Co and Cr, hot workability, which deteriorates as the content of Ni and Sn increases, is improved.
When one or two selected from Mg0.001~0.01wt% and Si0.005~0.2wt% are included, impurities such as S in the molten metal are removed, Cr loss is suppressed, and stability is achieved. It becomes possible to perform hot rolling. Mg is an element for removing impurities such as S, and if the content is less than 0.001wt%, this effect will be small, and if the content exceeds 0.01wt%, the flowability during agglomeration will deteriorate. , it becomes impossible to obtain a healthy ingot. Therefore, the Mg content is set to 0.001 to 0.01 wt%. Si is an element that is effective in suppressing the loss and loss of Cr; if the content is less than 0.005wt%, this effect is small, and if the content exceeds 0.2wt%, hot and cold workability is reduced. It gets noticeably worse. Therefore, the Si content is set to 0.005 to 0.2 wt%. In addition to the contained elements explained above, Mn, Fe, Al,
Even if one or more types of Zn are contained at 0.1wt% or less and P is contained at 0.01wt% or less, there is no effect on the hot workability of the copper alloy with excellent hot workability according to the present invention. No impact. [Example] Next, an example of a copper alloy having excellent hot workability according to the present invention will be described. Example A copper alloy having the components and proportions shown in Table 1 was ingot-formed by vertical continuous casting in an atmospheric atmosphere, and the ingot was heated to a temperature of 600°C or higher.
In addition, hot rolling is performed at a temperature below the melting point of this alloy with a reduction in area of 60% or more, which is sufficient to destroy the cast structure. In this hot rolling, Co and
Since it contains both Cr components, it exhibits good hot workability. Comparative ingots No. 8 to No. 10 shown in Table 1, which do not contain both Co and Cr, cracked on the wide and narrow surfaces during hot rolling, and the hot rolling failed. Since the ingots No. 1 to No. 7 of the copper alloy with excellent hot workability according to the present invention contain both Co and Cr components, cracks do not occur during hot rolling. is suppressed and exhibits good hot workability. Furthermore, this hot-rolled material undergoes cold rolling including one or more intermediate annealing steps, and then this cold-rolled material is heated to an α single-phase region determined mainly by the Ni and Sn contents, and then Solution treatment is performed by quenching in water or similar quenching treatment, resulting in an α single phase state. Then, this material is cold-rolled to the final thickness and subjected to final low-temperature annealing to produce a thin plate. This low temperature annealing significantly strengthens the sheet material. However,
This low-temperature annealing temperature is preferably in the range of 300 to 450°C; temperatures below 300°C take too long to strengthen the material, and temperatures above 450°C may cause some recrystallization. No improvement in strength can be expected. Next, ingots having the No. 1 and No. 2 content and component ratios of copper alloys with excellent hot workability according to the present invention shown in Table 1 were subjected to water cooling treatment at a starting temperature of 820°C and after completion of water cooling treatment. Hot rolling was carried out to achieve a reduction in area of 90%. Next, this hot rolled material was subjected to 700
Cold rolling was carried out including an intermediate annealing for 2 hours at a temperature of .degree. After holding this cold-rolled material at a temperature of 750°C for 1 minute, it was rapidly cooled in water, further subjected to up-rolling with a reduction in area of 30%, and then final low-temperature annealing was performed at a temperature of 400°C for 2 hours. Ta. The mechanical properties and material properties of No. 1 and No. 2 thus produced are shown in Table 2 as No. 1-1 and No. 2-1. In addition, when the final low-temperature annealing of No. 1 and No. 2 is not performed, the mechanical properties and physical properties of No. 1-2,
It is shown in Table 2 as No. 2-2. In addition, comparison material No. 11
The mechanical and physical properties of beryllium copper are also second to none.
Shown in the table. It can be seen from Table 2 that mechanical strength is greatly improved by performing final low temperature annealing. That is,
No.1-1 and No.2-1 subjected to final low temperature annealing
The tensile strength is 108.2Kgf/mm ² and 108.5Kgf/mm ² respectively.
, and the spring limit values are 80.3Kgf/mm ² , respectively.
Shows 76.0Kgf/mm ² and does not perform final low temperature annealing
Compared with No. 1-2 and No. 2-2, the tensile strength is 44.4Kgf/mm ² and 42.6Kgf/mm 2 , and the spring limit value is 44.3Kgf/mm ² and 38.0Kgf/mm ^{2 respectively} . It shows an increase. In addition, regarding growth, No. 1-1 and No. 2-1 showed an increase of 5.6% and 7.0%, respectively, and compared to No. 1-2 and No. 2-2, the increase was 3.4% and 3.7%, respectively. show. In addition, No. 1-1 and No. 2 were subjected to final low-temperature annealing.
-1 both exhibit mechanical properties equivalent to No. 11 beryllium copper used as a comparison material. Further, the copper alloy with excellent hot workability according to the present invention has excellent stress relaxation properties compared to beryllium copper (C17000). The stress relaxation properties of No. 1-1 in Table 2 at temperatures of 100°C and 200°C are shown in Figure 2 in comparison with No. 11 beryllium copper. As shown in Fig. 1, a sample 1 with a strain measurement gauge 2 pasted on a titanium holder 3 is attached to a bolt.
A load of 80% of the yield strength of sample 1 was applied using nut 4, and the sample was held at temperatures of 100°C and 200°C for a maximum of 1000 hours. After a certain period of time had elapsed, Sample 1 was removed from the above apparatus, and the stress relaxation rate was measured using the following equation. Stress relaxation rate (%) = (l ₀ − lt) / (l ₀ − _{l 1} ) × 100 l ₀ : Distance between the sample ends at the start of the test l ₁ : Holder length lt: Sample after t time has elapsed Distance between ends In other words, at a temperature of 100℃, both No. 1-1 and No. 11 show the same degree of stress relaxation characteristics, but at a temperature of 200℃
At a temperature of It shows good stress relaxation properties. In Fig. 2, -〇-: 200℃, ...〇...: 100℃ indicates No. 1-1 of the copper alloy with excellent hot workability according to the present invention, -△-: 200℃, ... △…: 100°C indicates No. 11 of comparative material beryllium copper.

【table】

[Table] [Effects of the Invention] As explained above, the copper alloy with excellent hot workability according to the present invention has the above structure, so Co is added to the Cu-Ni-Sn alloy. By simultaneously containing both the components of The ingredients can be sufficiently diffused through rolling, making it a homogeneous material with little anisotropy.Furthermore, it has mechanical properties comparable to beryllium copper, and requires high reliability. It will make a significant contribution to the field in which research is conducted.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an apparatus for a stress relaxation test, and FIG. 2 is a diagram showing the relationship between time and stress relaxation rate.

Claims (1)

[Claims] 1 Ni2-30wt%, Sn3-9wt%, Co0.01-1.0wt
%, Cr0.002 to 0.1wt%, and the remainder essentially consists of Cu.A copper alloy with excellent hot workability. 2 Ni2~30wt%, Sn3~9wt%, Co0.01~1.0wt
%, Cr0.002~0.1wt%, and further contains one or two selected from Mg0.001~0.01wt%, Si0.005~0.2wt%, and the remainder is essentially Cu. A copper alloy with excellent hot workability.