JPS62199742A - High strength copper alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a Cu alloy for an electrically conductive spring material having superior strength and electric conductivity by solidifying a molten Cu alloy contg. specified amounts of Be, Ni and Si by rapid cooling, cold working the solidified alloy and carrying out age precipitation. CONSTITUTION:A molten Cu alloy consisting of, by weight, 0.15-1.0% Ba, 0.5-6.0% Ni, 0.2-0.9%.Si and the balance Cu and having 1:(2.8-3.2):(0.8-1.2) atomic ratio of Be:Ni:Si is rapidly cooled at >=500 deg.C/sec cooling rate to form a thin plate having a fine solidified structure of 0.2-25mum grain size. The thin plate is cold worked at <=95% rate, subjected to annealing or soln. heat treatment at 550-1,000 deg.C, cold worked again at <=80% rate and aged at 250-550 deg.C to uniformly precipitate an intermetallic compound. Thus, a Cu alloy for an electrically conductive spring material having >100kg/mm<2> tensile strength, >350 Vickers hardness and superior electric conductivity is manufactured at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) 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) Typical conductive spring materials with excellent strength and conductivity include 1.8% Be, 0.25% CO, balance C, and JIS H3130 alloy number C1720. There is a precipitation hardening type alloy of u, but it has the disadvantage that it is expensive and the preparation price is extremely high because it contains a large amount of e. On the other hand, based on Cu, B, Si,
An alloy containing metalloid elements such as P, Ge, and Te and Be or S is rapidly solidified from a molten state to a particle size of 0.5 to 1.
By forming a rapidly solidified structure of 5 μm, conductivity, strength,
A new attempt to improve hardness etc. was made in 1986-4.
It is shown in the publication No. 311195. However, this alloy has poor conductivity because it contains a large amount of metalloid elements, insufficient hardness and strength, and poor bending formability due to low elongation and brittleness, so it cannot be used as a conductive spring material. It lacks practicality and is inferior to conventional precipitation hardening type Cu-Be alloys.

(Problems to be Solved by the Invention) The present invention solves these conventional problems, lowers the Be content, lowers the combined price, and
A high-strength copper-based alloy and a method for producing the same, which utilize a cold solidification method to refine the Ni weave and sufficiently satisfy the properties required for conductive spring materials such as hardness, strength, and conductivity. It was completed with the purpose of

(Means for solving the problem) The first invention of the present application contains Be 0.15 to 1.0% (wt%,
(same below), Ni 0.5-6.0%, Si 0.2
~0.9%, the balance Cu and unavoidable impurities in the rapidly solidified structure, the number of precipitation sites is increased by processing, and the precipitates after aging are uniformly dispersed, resulting in a Vickers hardness of 30.
It is characterized by having a hardness of 0 or more,
In addition, the second invention of the present application contains Be 0.15 to 1.0%, N
tO, 5-6, 0%, Si0, 2-0,
An alloy consisting of 9% Cu, the balance Cu and unavoidable impurities is rapidly solidified from a molten state to a crystal grain size of 0.2 to 25 μm.
After forming a rapidly solidified structure, cold working is performed to 95% or less, and an intermetallic compound is uniformly precipitated by aging precipitation treatment.

The present invention provides Cu exhibiting aging precipitation behavior as described above.
By rapidly cooling and solidifying the Be Ni-Si alloy from a molten state, an excessive amount of Be, which cannot be achieved by equilibrium solidification, can be obtained.
After obtaining an extremely fine rapidly solidified structure in which solute atoms such as Nl and Si are dissolved in the matrix, this is subjected to cold working to generate processing defects in the metal structure, and 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%, precipitation hardenability is insufficient and mechanical strength cannot be improved; .0%
If it exceeds this amount, the formation price will increase and the object of the present invention will not be achieved, and even if the rapid solidification method is used, the whole will not be able to be solidly dissolved in the matrix, and the effect of improving alloy properties commensurate with the increase in content will not be obtained. 0.15-1.0%
The range is preferably 0.4% to 0.8%. Next, like Be, Ni is also an element that imparts precipitation hardenability, and if it is less than 0.5%, precipitation hardenability is insufficient, and if it exceeds 6.0%, it will solidify in the matrix during rapid solidification. Since insoluble portions are generated 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. Also S
i causes intermetallic compounds to precipitate together with Ni, making it expensive.
Not only is it effective for improving mechanical strength without increasing the
It is an important element for improving oxidation resistance, etc., and is required to be present at least 0.2%, but if it exceeds 0.9%, the conductivity and rolling workability will be significantly deteriorated.
．． The content is preferably 2 to 0.9%, particularly preferably 0.4 to 0.8%. In order to bring these Be and Nis Si closer to the stoichiometric composition of the intermetallic compound that contributes to strengthening, the atomic ratio can be set in the range of 1:2.8 to 3.2:o, s to 1.2. preferable.

Such an alloy is instantaneously cooled and solidified from a molten state at a high rate of over 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, there are many elements such as Be, Ni, and Si that cannot be dissolved in solid form by equilibrium cooling. The amount is solidly dissolved in Matri Nox, and hardly any coarse precipitates that do not contribute to strengthening are formed. In the present invention, this structure is subjected to cold working of 95% or less by rolling or the like to generate processing defects within the structure, and if necessary,
After adding solution treatment at 0°C and cold working to 80% or less, aging precipitation treatment is performed at 250 to 500°C. Through these treatments, the number of precipitation sites due to processing increases in the rapidly solidified structure, and the Bes Nis St intermetallic compound precipitates uniformly and finely, and as shown in the data of the later examples, the hardness of the material increased to 300 on the Vickers hardness scale. In addition to the above, tensile strength, bending workability, etc. are significantly improved.

In particular, in the present invention, an excessive amount of Be,
Since Ni and Si elements are dissolved in the matrix, uniform and fine intermetallic compounds are precipitated all at once in a short time by aging precipitation treatment, which significantly improves hardness, strength, bending workability, etc. I can do it. Furthermore, in the present invention, even when solution treatment is performed, Be, Ni, and Si dissolved in solid solution by the rapid solidification method effectively suppress grain growth, and the grain size of the final structure does not exceed 25 μm. .

The degree of cold working was set to 95% or less because it was necessary to sufficiently generate processing defects in the structure, and the grain size was set to 0.2 to 2.5 μm. ,0
．． It is difficult to produce crystals smaller than 2 μm;
On the other hand, if it exceeds 25 μm, ductility and bending formability will decrease.

As described above, the alloy of the present invention has excellent hardness and strength despite its low beryllium content, and has a dense structure that provides excellent ductility and bending formability. Since it does not contain carbon, it has high conductivity suitable as a conductive spring material.

(Example) Alloys with various compositions of magnets 1 to 7 shown in Table 1 are jetted between rollers rotating at high speed, and rapidly solidified from a molten state at a speed of 500 °C/second or more to a thickness of 0. A thin plate of .35 m was made. These were treated in the treatment steps indicated by symbols a, b, c, d, etc. in Table 1, and their Vickers hardness, tensile strength, elongation, and electrical conductivity were measured and recorded in the same table. In addition, Table 2 shows the measured values for alloys whose alloy compositions are outside the range of the present invention when treated in the same manner as shown in Table 1. Fill-11h14 in Table 2 is a conventional technology. This is within the scope of the cited Japanese Patent Publication No. 60-43895.

In addition, the contents of the processing steps indicated by symbols a % h are the contents of the third
They are summarized in the table.

Table 1 Table 2 Table 3 (7) Field construction (effects of the invention) As is clear from the above explanation, the present invention lowers the Be content to lower the formation price, and also improves rapid solidification. The combination of cold working and aging precipitation treatment has succeeded in improving the properties required for conductive spring materials, such as hardness, strength, conductivity, and bending formability, in a well-balanced manner. As it eliminates the problems of Be alloys and conventional rapidly solidified alloys, it will greatly contribute to the development of industry.

Claims (1)

[Claims] 1. Be 0.15-1.0% (weight %, same hereinafter), N
i0.5-6.0%, Si0.2-0.9%, balance Cu
A high-strength copper characterized by having a hardness of 300 or more on the Vickers hardness scale by increasing the number of precipitation sites through processing and uniformly and finely dispersing the precipitates after aging treatment in the rapidly solidified structure consisting of unavoidable impurities. Base alloy. 2. Be, Ni, Si content: Be0.4-0.8%
, 2.0 to 5.0% Ni, and 0.4 to 0.8% Si. 3. The atomic ratio of Be, Ni, and Si is 1:2.8 to 3.2:
The high-strength copper-based alloy according to claim 1, wherein the strength is 0.8 to 1.2. 4. 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. 5, Be0.15-1.0%, Ni0.5-6.0%,
An alloy consisting of 0.2 to 0.9% Si, the remainder Cu, and unavoidable impurities is rapidly solidified from a molten state to a grain size of 0.9%.
A method for producing a high-strength copper-based alloy, characterized in that after forming a rapidly solidified structure of 2 to 25 μm, cold working is performed to 95% or less, and further, intermetallic compounds are uniformly and finely precipitated by aging precipitation treatment. 6. The method for producing a high-strength copper-based alloy according to claim 5, wherein the rapid solidification is performed at a rate of 500° C./second or more. 7. After cold working, perform annealing or solution treatment at 550 to 1000°C and cold working to 80% or less, and then
The method for producing a high-strength copper-based alloy according to claim 5, wherein the aging precipitation treatment is performed at 550°C.