JPH0240725B2 - BANEYOKOKYODODOGOKINOYOBISONOSEIZOHO - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a high-strength copper alloy for springs that is suitable as a spring material for electrical and electronic components that are required to be non-magnetic and have high electrical conductivity, and a method for manufacturing the same. [Prior art and its problems] Spring materials for electrical and electronic components, which are a type of conductive component, are required to be non-magnetic and have excellent electrical conductivity. Conventionally, this type of conductive spring material has been made of, for example, brass, nickel silver, phosphor bronze, or beryllium copper. However, brass is inferior in terms of strength, elasticity, and reliability, and nickel silver and phosphor bronze have the drawbacks of being slightly insufficient in strength and elasticity, and having poor stress relaxation properties at temperatures above 100°C. Additionally, beryllium copper has the drawbacks of being expensive and prone to stress relaxation at temperatures above 150°C. Age-hardening titanium copper, which contains copper with a suitable amount of Ti, has recently been developed. This Ti-Cu binary copper alloy is known to have strength and elasticity superior to brass, nickel silver, and phosphor bronze, and its heat resistance and stress relaxation properties are superior to conventional copper alloys containing beryllium copper. There is. However, this Ti--Cu binary alloy requires solution treatment, quenching, and aging treatment, and is difficult to cast and hot-roll, resulting in significant manufacturing constraints and high costs. In addition, the crystal grains of this alloy tend to coarsen during solution treatment, and grain boundary reactions tend to occur during aging treatment, so there are various problems in effectively demonstrating its original properties. be. The present invention was made with the aim of solving the problems of such conventional conductive spring materials. [Means for Solving the Problems] The present invention provides Ti of 1.0 to 2.0% by weight and 0.1% of Ti by weight.
The present invention provides a high-strength copper alloy for springs containing ~2.0% Ni in a Ti/Ni ratio of 1 to 5, with the remainder consisting of Cu and unavoidable impurities. The alloy of the present invention can form Cu-Ti intermetallic compounds, Ti-Ni intermetallic compounds and/or Cu-Ti- The basic feature is that the Ni-based intermetallic compound is finely dispersed and precipitated in the Cu matrix to exhibit various properties desirable for spring materials. As a method for producing the alloy of the present invention in order to advantageously exhibit various properties desirable for this spring material, 1.0 to 2.0% Ti and 0.1 to 2.0% Ti and 0.1 to 2.0% by weight are used.
A process of manufacturing a slab containing Ni in a Ti/Ni ratio of 1 to 5, with the balance consisting of Cu and unavoidable impurities, and rolling this slab at a rolling reduction of 60% or more and a hot rolling finishing temperature.
A process of hot rolling at 850°C or higher and then cooling from the hot-rolled finishing temperature to a temperature of 300°C or lower at a cooling rate of 30°C/min or higher to obtain a hot-rolled sheet, the obtained hot-rolled sheet The first cold rolling is performed at a reduction rate of 50% or more, followed by annealing at a temperature of 300 to 600°C for 5 to 720 minutes.The obtained cold rolled sheet is cooled to the target thickness. A process of reducing the plate thickness by inter-rolling (or cold rolling with intermediate annealing in the case of several cold rollings), and after the final cold rolling, rolling at a temperature of 300 to 750°C for 5 to 50 minutes. 180
The present invention provides a method for manufacturing a high-strength copper alloy for springs, which comprises the steps of performing tension annealing for seconds. [Detailed Description of the Invention] First, the reason for selecting the content range of the additive element in the copper alloy of the present invention will be explained. Cu-Ti based intermetallic compound, Ti-Ni based intermetallic compound and/or Cu-Ti-Ni based intermetallic compound
Ti and Ni are essential elements in the alloy of the present invention, which is strengthened by precipitation in a Cu matrix. If the Ti content is less than 1.0% by weight, there will be little effect on improving strength, elasticity and heat resistance even in the coexistence with Ni.
If Ti is contained in an amount exceeding 2.0% by weight, the amount of precipitates will increase excessively, reducing the ductility and bendability of the alloy, so the Ti content should be in the range of 1.0 to 2.0% by weight. By forming a compound with Ti, Ni contributes to improving the strength, elasticity, and heat resistance of the alloy, and also contributes to refining the hot structure and suppressing grain boundary reactions during aging treatment. In order to exhibit such an effect, a Ni content of 0.1% by weight or more is required.
However, if the content exceeds 2.0% by weight, Ti-Ni
Precipitation of the system compounds progresses, resulting in a significant decrease in ductility and bendability. Therefore, the Ni content is 0.1~
The range is 2.0% by weight. These Ti and Ni elements exhibit their original effectiveness when precipitated as Cu-Ti intermetallic compounds, Ti-Ni intermetallic compounds, and/or Cu-Ti-Ni intermetallic compounds. It is necessary to adjust the blending ratio of each element within the above content range so that Ti/Ni is in the range of 1 to 5 in terms of weight %. When the Ti/Ni ratio is less than 1, Ti
-Since the precipitation of Ni-based compounds is small, the electrical conductivity is low, and the hot structure tends to become coarse, resulting in a decrease in bendability. On the other hand, if the Ti/Ni ratio is greater than 5, a large amount of Ti-Ni compounds will precipitate, and although the electrical conductivity will improve, the bendability will significantly decrease. For this reason, in the range of Ti: 1.0 to 2.0 wt% and Ni: 0.1 to 2.0 wt%, Ti/Ni
It is necessary to adjust the value in the range of 1 to 5, and thereby, the Cu-Ti based intermetallic compound, Ti-Ni based intermetallic compound and/or Cu-Ti-Ni based intermetallic compound can be mixed into a Cu matrix. It can be finely precipitated inside the spring material to provide the various properties required for the spring material. In order to develop the properties required of a conductive spring material through the precipitation of such intermetallic compounds, certain conditions must be met when processing a cast slab into a material with the desired thickness through hot rolling and cold rolling. This can be advantageously achieved by appropriately controlling the The details of the manufacturing method will be explained below in the order of steps. Hot rolling process A slab with Ti and Ni content and Ti/Ni ratio adjusted to the above range is produced by melting and casting, and this slab (ingot) is subjected to hot rolling. At this time, it is preferable to heat the slab to 900°C or higher, set the hot rolling reduction ratio to 60% or higher, and set the hot rolling finishing temperature to 850°C or higher. As a result, the cast structure can be completely crushed, and the influence of segregation occurring in the ingot can be eliminated. Then, it is cooled at a cooling rate of 30°C/min or more in the temperature range from the hot rolling finishing temperature to 300°C or less. This cooling is preferably carried out by performing rapid water cooling immediately after hot rolling. This makes it possible to obtain a hot-rolled material in which Ti and Ni are completely dissolved in solid solution. It has been found that if the cooling after hot rolling is performed at a cooling rate slower than 30° C./min, these elements will precipitate during the cooling process to form coarse compounds. Furthermore, it was found that even when cooling was performed at a cooling rate of 30°C/min or more, coarse compounds were similarly produced when the quenching start temperature was lower than 850°C. The precipitates that precipitate at this stage are coarse, and these coarse precipitates cannot be expected to improve the strength, elasticity, and heat resistance of the alloy, and on the contrary, have a negative effect on bendability. In order to eliminate these coarse precipitates, solution treatment must be performed, which increases costs. In the present invention, Ti and Ni
One of the characteristics is that hot rolling conditions are adopted such that a hot rolled sheet in which is completely dissolved in solid solution is obtained. Note that the cooling end point temperature during this rapid cooling may be 300°C or less. This is because precipitation does not substantially occur at temperatures below 300°C. Cold rolling and annealing process The hot rolled sheet obtained in the previous process with Ti and Ni completely dissolved in solid solution is then subjected to surface grinding or pickling as necessary, and then cold rolling with annealing several times. At this stage, Cu-Ti intermetallic compounds, Ti-Ni intermetallic compounds, and /Or finely precipitate a Cu-Ti-Ni intermetallic compound. In other words, the first cold rolling is performed at a reduction rate of 50% or more, and the annealing after this first cold rolling is
It is carried out at a temperature of 300 to 600°C for 5 to 720 minutes. The conditions of this first cold rolling and annealing are extremely important in the method of the present invention. If the reduction ratio in the first cold rolling is less than 50%, the rolled structure will not become homogeneous, and in the subsequent annealing, Cu
-Ti-based intermetallic compounds, Ti-Ni-based intermetallic compounds, and/or Cu-Ti-Ni-based intermetallic compounds cannot be finely precipitated. If this initial cold rolling is followed by annealing at a temperature exceeding 600°C, the precipitates will become coarse and no improvement in properties can be expected. Further, a temperature lower than 300°C is not preferable because the time required for precipitation is too long. Therefore, the temperature of this first annealing is 300-600
It is preferable to carry out the annealing at ℃, and if the annealing time is less than 5 minutes, the formation of precipitates will be insufficient.
In addition, if the time is longer than 720 minutes, it is unfavorable from the viewpoint of precipitate growth and economical aspects.
It is better to make it a minute. By performing the first cold rolling and annealing under these conditions, Cu-Ti intermetallic compounds, Ti-Ni intermetallic compounds, and/or Cu-Ti-Ni intermetallic compounds were finely precipitated. materials can be obtained. Thereafter, the plate thickness may be reduced by performing cold rolling to a desired thickness. If cold rolling is performed several times during this process, intermediate annealing may be performed. Tension annealing process A tension annealing process is performed at a temperature of 300 to 750°C for 5 to 180 seconds while applying an appropriate tension to a cold rolled material that has been cold rolled to a desired thickness. By this tension annealing treatment, a homogeneous and highly flat product can be obtained, and the ductility and bendability of the material are improved. When carrying out tension annealing treatment, a temperature of less than 300° C. takes a long time to exhibit these effects, which is undesirable from the standpoint of oxidation and economic efficiency. Furthermore, at temperatures exceeding 750°C, the material softens even for a short period of time. Regarding the treatment time, homogenization is insufficient if the treatment time is less than 5 seconds, and no difference in effect appears even if the treatment time exceeds 180 seconds. For this reason, tension annealing is preferably carried out at a temperature of 300 to 750°C for 5 to 180 seconds. Examples are given below to specifically demonstrate the effects of the alloy of the present invention. [Example] No. 1 whose chemical component values (weight %) are shown in Table 1
~ No. 9 copper alloy is melted using a high frequency melting furnace,
An ingot measuring 400mm x 30mm x 140mm was cast. This ingot was cut into a size of 40 mm x 30 mm x 5 mm, and the ingot was soaked at 950°C, then hot rolled to a thickness of 1.2 mm, and cooled in water from a temperature of 900°C. The cooling rate at this time was well over 30°C/min, and the end point temperature was well below 300°C. The obtained hot-rolled sheet was face-milled to a thickness of 1.0 mm, and then cold-rolled to a thickness of 0.45 mm. Next, this cold-rolled sheet was annealed at 500°C for 60 minutes. Then, cold rolling was performed at a reduction rate of 10% to reduce the thickness.
A cold-rolled sheet of 0.4 mm was obtained. 8 kg of the obtained cold rolled plate
Tension annealing was performed at 400° C. for 30 seconds while applying a tension of f/mm ² . The material that had undergone this treatment was used as a test material. Using the obtained test materials, hardness, tensile strength, spring limit value, electrical conductivity, heat resistance, and bendability were investigated. The results are also listed in Table 1. Measurement of hardness, tensile strength, spring limit value and electrical conductivity are each based on JIS Z
2244, JIS Z 2241, JIS H 3130 and JIS
It was carried out according to H 0505. Heat resistance is 400℃ temperature
If the hardness after heating and holding for 30 minutes was 80% or more of the initial hardness, it was evaluated as ○, and if it was less than 80%, it was evaluated as ×. The bendability was determined by the 90°W bending test (CES-
M0002-6, R = 0.3 mm), and those with a good center ridge surface were evaluated as ◯, those with wrinkles as △, and those with cracks as ×.

[Table] The following is clear from the results in Table 1. Alloys No. 1 to No. 5 according to the present invention have an excellent balance of hardness, tensile strength, spring limit value, and electrical conductivity, and also have good heat resistance and bendability. Therefore, it can be seen that this is an extremely excellent alloy as a high-strength material for conductive springs. On the other hand, Comparative Alloy No. 6, which contains less Ti than the amount specified in the present invention, has low hardness, low tensile strength, and low spring limit values. Comparative alloy No. 7, which contains more Ti than the amount specified in the present invention, has poor bendability. and,
Even though the content of Ti and Ni is within the range specified by the present invention, comparative alloy No. 1 with a Ti/Ni ratio greater than 5.
8, and comparative alloy No. 8 with a Ti/Ni ratio less than 1.
No. 9 both had poor bendability. As described above, the present invention provides a copper alloy for springs that has high strength and high elasticity, as well as excellent heat resistance and bendability, and enables electrical and electronic components to be made lighter, thinner, shorter, and more reliable. It is something.

Claims (1)

[Claims] 1 1.0-2.0% Ti and 0.1-2.0% by weight
A high-strength copper alloy for springs containing Ni in a Ti/Ni ratio of 1 to 5, with the balance being Cu and unavoidable impurities. 2 1.0-2.0% Ti and 0.1-2.0% by weight
A process of manufacturing a slab containing Ni in a Ti/Ni ratio of 1 to 5, with the balance consisting of Cu and unavoidable impurities, and rolling this slab at a rolling reduction of 60% or more and a hot rolling finishing temperature.
A process of hot rolling at 850°C or higher and then cooling from the hot-rolled finishing temperature to a temperature of 300°C or lower at a cooling rate of 30°C/min or higher to obtain a hot-rolled sheet, the obtained hot-rolled sheet The first cold rolling is performed at a reduction rate of 50% or more, followed by annealing at a temperature of 300 to 600°C for 5 to 720 minutes.The obtained cold rolled sheet is cooled to the target thickness. The process of reducing the plate thickness by inter-rolling, and after the final cold rolling, it is rolled at a temperature of 5 to 180℃ at a temperature of 300 to 750℃.
A method for manufacturing a high-strength copper alloy for springs, comprising the steps of performing tension annealing for seconds. 3. The manufacturing method according to claim 2, wherein the step of reducing the plate thickness by cold rolling to the target plate thickness is performed by cold rolling several times with intermediate annealing interposed.