JPH0356295B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a high-strength copper-based alloy having excellent strength and conductivity and suitable for use as a conductive spring material. (Prior art) A typical conductive spring material with excellent strength and conductivity is a precipitation hardening alloy of 1.8% Be, 0.25% Co, and the balance Cu specified as alloy number C1720 in JIS H3130. However, it has the disadvantage that the combined price is extremely high because it contains a large amount of expensive Be. On the other hand, based on Cu, B,
An alloy containing metalloid elements such as Si, P, Ge, Te, etc. and Be or S is rapidly solidified from a molten state to obtain particle size.
A new attempt to improve conductivity, strength, hardness, etc. by creating a rapidly solidified structure of 0.5 to 15 μm is disclosed in Japanese Patent Publication No. 43895/1983. However, this alloy is not suitable as a conductive spring material because it contains a large amount of semi-metallic elements, resulting in poor conductivity, insufficient hardness and strength, and low elongation and brittleness, resulting in poor bending formability. It lacked practicality and was inferior to conventional precipitation hardening type Cu-Be alloys. (Problems to be solved by the invention) The present invention solves these conventional problems,
In addition to lowering the Be content and lowering the formation price, the rapid solidification method is used to achieve a finer structure, and the properties required for conductive spring materials, such as hardness, strength, and conductivity. This was completed with the aim of creating a high-strength copper-based alloy and its manufacturing method that can fully satisfy the following requirements. (Means for solving the problem) The first invention of the present application has Be0.15 to 1.0% (weight%,
(same below), Ni, Co, or both in total amount
0.5 to 6.0%, the balance being Cu and unavoidable impurities, with an atomic ratio of Be:Ni+Co of 1:0.8 to 1.2,
In addition, in the rapidly solidified structure with a crystal grain size of 0.2 to 25 μm, the number of precipitation sites is increased by processing, and the precipitates after aging are uniformly and finely dispersed, resulting in a hardness of Bitkers hardness.
The gist is a high-strength copper-based alloy characterized by having properties of 300% or more and an elongation of 3% or more. In addition, the second invention of the present application has Be0.15 to 1.0%, Ni,
One or both of Co is 0.5 to 6.0% in total amount, the balance is Cu
and unavoidable impurities, and the atomic ratio of Be:Ni+Co is 1:0.8 to 1.2.
The crystal grain size is reduced by rapid solidification at a speed of 500℃/second or more.
A method for producing a high-strength copper-based alloy, which is characterized in that after forming a rapidly solidified structure of 0.2 to 25 μm, cold working is performed to 95% or less, and intermetallic compounds are uniformly and finely precipitated by aging precipitation treatment. This is a summary. The alloy with the above composition is Cu-Be shown in Figure 1.
- As seen in the equilibrium phase diagram of the 3% Ni cross section of the -Ni alloy, the solid solubility limit of Be and Ni at room temperature is extremely narrow, so it is an alloy that inherently has excellent precipitation hardenability. However, in materials that have gone through the normal melting and casting process, most of the Be and Ni are discharged from the matrix as precipitates, and do not easily dissolve into the matrix even after hot working or annealing, resulting in precipitation hardening. becomes insufficient. In addition, solution treatment cannot be carried out at very high temperatures in order to prevent grain coarsening, and is usually carried out at 900 to 950°C, but at this temperature, the precipitates Be and Ni are completely absorbed into the matrix. Not dissolved in solid solution. However
In the case of non-equilibrium solidification associated with rapid solidification at a rate exceeding 500℃/sec, the solid solubility of Be, Ni, Co, etc. in the matrix increases, and the precipitation strengthening effect in the subsequent aging precipitation treatment becomes significant. . In addition, Be, Ni, Co, etc., which are once dissolved as a solid solution during solidification, effectively suppress grain growth even when solution treatment is performed after solidification, and even if the solution treatment temperature is increased, grain growth is significantly suppressed. It has the characteristics of In the present invention, by rapidly cooling and solidifying a copper-based alloy exhibiting aging precipitation behavior as described above from a molten state, excessive amounts of Be, Ni,
After obtaining an extremely fine rapidly solidified structure in which solute atoms such as Co are dissolved in the matrix, cold working is performed to generate processing defects in the metal structure, and this is then subjected to aging precipitation treatment. By uniformly and finely precipitating a large amount of intermetallic compounds, we succeeded in increasing hardness, strength, and bending formability. Next, each component of the present invention will be explained in more detail. Be in the copper-based alloy of the present invention is a basic element for producing precipitation hardenability, and if it is less than 0.15%, the precipitation hardenability is insufficient and no improvement in mechanical strength can be obtained; If it exceeds the amount, the formation price will increase and the object of the present invention will not be achieved, and the whole will not be able to be solid-dissolved in the matrix by the rapid solidification method, and the effect of improving alloy properties commensurate with the increase in content will not be obtained. The content should be in the range of 0.15 to 1.0%, and the range of 0.4 to 0.8% is particularly optimal. next
Like Be, Ni and Co are elements that impart precipitation hardenability, and if the total amount is less than 0.5%, precipitation hardenability is insufficient, and if it exceeds 6.0%, they will solidify in the matrix during rapid solidification. Since some portions are not soluble and the conductivity is deteriorated, it is necessary to set the content to 0.5 to 6.0%, and a range of 2.0 to 5.0% is particularly preferable. Either or both of these Ni and Co may be used within the above range. Be
The atomic ratio of Ni+Co and Ni+Co is set at 1:0.8 to 1:0.8 to bring it closer to the stoichiometric composition of the intermetallic compound that contributes to strengthening.
The range shall be 1.2. This allows intermetallic compounds to be generated all at once without waste. Such an alloy is instantaneously cooled and solidified from a molten state at a high speed exceeding 500° C./second by, for example, being poured between rotating rollers. As a result of such rapid solidification, a fine rapidly solidified structure with a grain size of 0.2 to 25 μm is obtained, and as mentioned above,
A large amount of elements such as Be, Ni, and Co, which cannot be dissolved in solid form by equilibrium cooling, dissolves in solid solution in the matrix, and hardly any coarse precipitates that do not contribute to strengthening are generated. In the present invention, this structure is formed by rolling etc.
After applying cold working of 95% or less to create processing defects in the structure, and further adding solution treatment at 550 to 1000°C and cold working of 80% or less as necessary,
Aging precipitation treatment is performed at 250-500℃. Through these treatments, the number of precipitation sites due to processing increases in the rapidly solidified structure, and the intermetallic compounds of Be, Ni, and Co precipitate uniformly and finely, and as shown in the data of the later examples, the hardness of the material increases. Hardness 300 or more, elongation 3
% or more, and tensile strength, bending workability, etc. are significantly improved. In particular, in the present invention, an excessive amount of Be, Ni, or Co is dissolved in the matrix at a predetermined atomic ratio using the rapid solidification method. The compounds precipitate all at once, making it possible to significantly improve hardness, elongation, strength, bending workability, etc. In addition, in the present invention, even when solution treatment is performed, Be, Ni, or Co dissolved in solid solution by the rapid solidification method effectively suppresses grain growth, and the grain size of the final structure does not exceed 25 μm. . In addition, the degree of cold working was set to 95% or less because
This is because it is necessary to sufficiently generate processing defects in the structure, and the reason why the crystal grain size is set to 0.2 to 2.5 μm is because it is difficult to generate crystals smaller than 0.2 μm, and conversely, it is difficult to generate crystals smaller than 25 μm. This is because ductility and bending formability decrease. Furthermore, the Vickers hardness of the obtained alloy was limited to 300 or more and the elongation was limited to 3% or more, in order to clarify the preferable range for a particularly conductive spring material. As described above, the alloy of the present invention has excellent hardness, elongation, and strength despite its low beryllium content, and has a dense structure that provides excellent ductility and bending formability. Since it contains almost no carbon, it has high conductivity and is suitable as a conductive spring material. (Example) Alloys of various compositions No. 1 to No. 15 shown in Table 1 were sprayed between rollers rotating at high speed, and
A thin plate with a thickness of 0.31 mm was produced by rapid solidification from a molten state at a rate of at least ℃/second. After processing this through the processing steps indicated by symbols a, b, c, d, etc. in Table 1, the Vickers hardness, tensile strength, elongation, etc.
The electrical conductivity was measured and recorded in the same table. Additionally, Table 2 shows alloys whose alloy compositions are outside the scope of the present invention (No. 1 to 7), ordinary process products (No. 8 to 9), and alloys within the range of Japanese Patent Publication No. 60-43895 (No. 10). -12), the same measured values as shown in Table 1 are shown. In addition, a
The contents of the treatment steps indicated by symbols ~g are summarized in Table 3.

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[Table] (Effects of the invention) As is clear from the above description, the present invention has the following effects:
In addition to lowering the formation price by lowering the Be content, the combination of rapid solidification, cold working, and aging precipitation treatment improves the various properties required for conductive spring materials such as hardness, strength, conductivity, and bending formability. Since it has been successfully improved in a well-balanced manner, it is better than the conventional
Since the problems of Cu-Be alloy and conventional rapidly solidified alloys have been eliminated, it will greatly contribute to the development of industry.

[Brief explanation of drawings]

FIG. 1 is an equilibrium phase diagram of a 3% Ni cut section of a Cu-Be-Ni alloy.

Claims (1)

[Claims] 1 Be 0.15 to 1.0% (weight%, same hereinafter), Ni,
One or both of Co is 0.5 to 6.0% in total amount, the balance is Cu
and unavoidable impurities, the atomic ratio of Be:Ni+Co is 1:0.8~1.2, and the crystal grain size is 0.2~
In the rapidly solidified structure of 25 μm, the number of precipitation sites is increased by processing, and the precipitates after aging are uniformly and finely dispersed, resulting in a Bitkers hardness of 300 or more and an elongation of 3%.
A high-strength copper-based alloy characterized by having the above properties. 2 The content of Be, Ni, and Co is 0.4% to 0.8%, Ni
The high-strength copper-based alloy according to claim 1, wherein the total amount of Co is 2.0 to 5.0%. 3. The high-strength copper-based alloy according to claim 1, which has a tensile strength of 100 Kg/mm ² or more and a Vickers hardness of 350 or more. 4 Melt an alloy consisting of 0.15 to 1.0% Be, 0.5 to 6.0% in total of one or both of Ni and Co, and the balance Cu and unavoidable impurities, with an atomic ratio of Be:Ni+Co of 1:0.8 to 1.2. From the state, the material is rapidly solidified at a speed of 500°C/second or more to form a rapidly solidified structure with a grain size of 0.2 to 25 μm, then cold worked to 95% or less, and then subjected to aging precipitation treatment to make the intermetallic compounds uniform and fine. A method for producing a high-strength copper-based alloy characterized by precipitation. 5 After cold working, perform annealing or solution treatment at 550 to 1000℃ and cold working to 80% or less, and then 250
The method for producing a high-strength copper-based alloy according to claim 4, wherein the aging precipitation treatment is performed at ~550°C.