JP2011179069A - Method for producing titanium copper for electronic part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide titanium copper in which a balance between strength and bending workability is improved. <P>SOLUTION: The copper alloy has a composition comprising Ti of, by mass, 2.0 to 4.0%, and comprising, as a third additive element(s), one or more selected from Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B and P by 0 to 0.5% in total, and the balance copper with inevitable impurities, and in which the average number density (Y) of the second phase grains with a grain size of 0.05 to 1.0 &mu;m obtained by microscopic examination in the cross-section parallel to the rolling direction is 10 to 20 pieces/&mu;m<SP>2</SP>, and 0.2% proof stress (YS) is reduced by &ge;400 MPa when heat treatment is applied for 5hrs at a material temperature of 550&deg;C. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  In recent years, electronic devices typified by portable terminals and the like have been increasingly miniaturized, and accordingly, connectors used therefor have a tendency of narrow pitch and low profile. The smaller the connector, the narrower the pin width and the smaller the folded shape, so the material used must have high strength to obtain the necessary spring properties and excellent bending workability that can withstand severe bending work. It is done.

  In this regard, a copper alloy containing titanium (hereinafter referred to as “titanium copper”) has a relatively high strength and the best stress relaxation characteristics among copper alloys. It has been used for a long time as a signal system terminal material. Titanium copper is an age-hardening type copper alloy. Specifically, when a supersaturated solid solution of Ti, which is a solute atom, is formed by solution treatment, and heat treatment is performed at a low temperature for a relatively long time from that state, periodic fluctuations in Ti concentration in the parent phase due to spinodal decomposition The modulation structure is developed and the strength is improved. Based on this strengthening mechanism, various methods have been studied with the aim of further improving the properties of titanium copper.

  At this time, the problem is that the strength and the bending workability are contradictory. That is, if the strength is improved, the bending workability is impaired, and conversely, if the bending workability is emphasized, a desired strength cannot be obtained. Therefore, a third element such as Fe, Co, Ni, Si or the like is added (Patent Document 1), the concentration of the impurity element group that dissolves in the matrix phase is regulated, and these elements are added to the second phase particles (Cu-Ti- X-type particles) are precipitated in a predetermined distribution form to increase the regularity of the modulation structure (Patent Document 2), and the density of the trace additive elements and second-phase particles effective to refine the crystal grains is specified. From the viewpoints of (Patent Document 3), etc., research and development have been made in order to achieve both the strength and bending workability of titanium copper.

  Patent Document 1 describes that titanium copper having a maximum 0.2% proof stress of 888 MPa was obtained, and MBR / t at this time was 0.7 (Example No. 10). Patent Document 2 describes that titanium copper having a maximum 0.2% proof stress of 839 MPa was obtained, and MBR / t at this time was 1.7 (Example No. 10). Patent Document 3 describes that titanium copper having a maximum 0.2% proof stress of 888 MPa was obtained, and MBR / t at this time was 0.5 (Example No. 10).

Further, in Patent Document 4, in the case of titanium copper, there exists a β phase (TiCu ₃ ) having poor consistency with the α phase as a parent phase and a β ′ phase (TiCu ₄ ) having good consistency, and the β phase Titanium with finely dispersed β 'phase while suppressing β phase, while having an adverse effect on bendability, and that uniform and finely dispersing β' phase contributes to both strength and bending workability Copper is disclosed. Patent Document 4 describes that titanium copper having a maximum 0.2% proof stress of 1019 MPa was obtained, and MBR / t at this time was 2 (Example No. 4).

Also, in these documents, titanium copper is manufactured in the order of melting casting of ingot → homogenization annealing → hot rolling → (repetition of annealing and cold rolling) → final solution treatment → cold rolling → aging treatment. It is described. In particular, in the final solution treatment, it is important to suppress the precipitation of second phase particles that are inconsistent with the stable phase of TiCu ₃ or the parent phase.

Japanese Patent Laid-Open No. 2004-231985 JP 2004-176163 A JP-A-2005-97638 JP 2006-283142 A

  In this way, titanium copper is generally manufactured in the order of melt casting of ingot → homogenization annealing → hot rolling → (repetition of annealing and cold rolling) → final solution treatment → cold rolling → aging treatment. The improvement of the characteristics has been attempted on the basis of this process. However, there is still room for improvement in the balance between strength and bending workability in titanium copper.

  Accordingly, an object of the present invention is to provide titanium copper having an improved balance between strength and bending workability. Moreover, this invention makes it another subject to provide the electronic component provided with such titanium copper. Moreover, this invention makes it another subject to provide the manufacturing method of such titanium copper.

  In the conventional titanium copper manufacturing method, titanium is sufficiently dissolved in the matrix by the final solution treatment, then cold rolled to increase the strength to a certain extent, and finally spinodal decomposition is caused by aging treatment. High strength titanium copper was obtained. For this reason, it has not been considered to carry out a heat treatment before the cold rolling, in which the stable phase of titanium solid-dissolved by the final solution treatment may precipitate as second phase particles.

  However, as a result of diligent research, the inventor has performed a aging treatment under a predetermined condition after the final solution treatment, and titanium titanium manufactured by a cold rolling process thereafter has a balance between strength and bending workability. It was found to improve significantly. After cold rolling, the strength can be further increased by further annealing under predetermined conditions.

  One of the features of the titanium copper according to the present invention thus obtained is that the number density of the second phase particles is higher than that of the conventional titanium copper. Another point is that the strength decrease after performing a predetermined heat treatment is larger than that of conventional titanium copper.

The present invention completed on the basis of the above, in one aspect, contains 2.0 to 4.0% by mass of Ti, and the third additive element is Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, It is a copper alloy containing 0 to 0.5% by mass in total of one or more of Zr, Si, B, and P, and is composed of the remaining copper and unavoidable impurities. The average number density (Y) of the observed second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less is 10 to 20 particles / μm ² , and a heat treatment is performed at a material temperature of 550 ° C. for 5 hours. It is a copper alloy whose 0.2% yield strength (YS) decreases by 400 MPa or more.

In one embodiment of the copper alloy according to the present invention, the average number density (X) of the second phase particles having a particle diameter of more than 1.0 μm observed by a spectroscopic cross section parallel to the rolling direction is 0.15 / μm ² or less.

  In another embodiment of the copper alloy according to the present invention, the area ratio of the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less observed by a microscopic cross section parallel to the rolling direction is 4.0. ~ 15.0%.

  In still another embodiment of the copper alloy according to the present invention, the average crystal grain size is 3 to 30 μm.

  In another aspect of the present invention, Ti is contained in an amount of 2.0 to 4.0% by mass, and the third additive element is Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, A method for producing a copper alloy comprising 0 to 0.5% by mass in total of one or more of B and P, the balance being copper and unavoidable impurities, wherein the material is a solid solution of Ti at 730 to 880 ° C. Aging performed under the condition of heating at a material temperature of 400 to 500 ° C. for 0.5 to 24 hours after the final solution treatment performed under the condition of heating for 0.5 to 3 minutes at a temperature equal to or higher than the addition amount. It is a manufacturing method which performs processing and cold rolling in order.

  In one embodiment of the method for producing a copper alloy according to the present invention, after the cold rolling, annealing is further performed under the condition of heating at a material temperature of 250 to 550 ° C. for 0.001 to 0.5 hours.

  In another aspect, the present invention is an electronic component including the copper alloy according to the present invention.

  The electronic component according to the present invention is a connector in one embodiment.

  According to the present invention, titanium copper having an improved balance between strength and bending workability can be obtained.

  The reason why the characteristics are improved by the production method of the present invention has not been sufficiently elucidated, but this is presumed as follows. In titanium copper, as the titanium modulation structure develops in the aging treatment, the amplitude of the titanium concentration change (light and shade) increases, but when it reaches a certain amplitude, near the peak where it can no longer withstand fluctuations The titanium changes to a more stable β ′ phase and further to a β phase. That is, titanium dissolved in the mother phase by solution treatment gradually develops a modulation structure, which is a periodic variation of Ti concentration, by applying heat treatment thereafter, and this is a metastable phase β 'Change to phase, and finally to β phase, which is a stable phase. However, after the final solution treatment and before cold rolling, if an aging treatment that can cause spinodal decomposition is performed in advance, the β ′ phase is not reached even when the β ′ phase should normally precipitate during the aging treatment. It becomes difficult to precipitate, the development limit of the modulation structure by spinodal decomposition becomes larger than conventional titanium copper, and the degree of aging treatment that reaches the peak of strength is considered to be larger than the conventional one. As a result, although the precipitation amount of the second phase particles is larger than that of conventional titanium copper, it is considered that the strength can be increased as compared with titanium copper produced by the conventional manufacturing method.

  Further, although the amount of precipitation of the second phase particles defined in the present invention is larger than that of the conventional titanium copper, the reason why good bending workability can be obtained has not been fully clarified. It is conceivable that the precipitation is uniform and there is little precipitation at the grain boundary.

<Ti content>
If Ti is less than 2.0% by mass, a sufficient strengthening mechanism cannot be obtained due to the formation of the original modulation structure of titanium copper, so that sufficient strength cannot be obtained. Conversely, if Ti exceeds 4.0% by mass, coarse TiCu ₃ tends to precipitate, and the balance between strength and bending workability tends to deteriorate. Therefore, the content of Ti in the copper alloy according to the present invention is 2.0 to 4.0 mass%, preferably 2.7 to 3.5 mass%. Thus, by optimizing the Ti content, both strength and bending workability suitable for electronic components can be realized.

<Third element>
Since the third element contributes to the refinement of crystal grains, a predetermined third element can be added. Specifically, even if the solution treatment is performed at a high temperature at which Ti is sufficiently dissolved, the crystal grains are easily refined and the strength is easily improved. The third element also promotes the formation of the modulation structure. Furthermore, there is an effect of suppressing precipitation of TiCu ₃ . Therefore, the original age hardening ability of titanium copper can be obtained.

  In titanium copper, Fe has the highest effect. And in Mn, Mg, Co, Ni, Si, Cr, V, Nb, Mo, Zr, B, and P, the effect according to Fe can be expected, and even if added alone, the effect is seen, but two or more Multiple additions may be made.

  When these elements contain a total of 0.05% by mass or more, the effect appears. However, when the total exceeds 0.5% by mass, the solid solubility limit of Ti is narrowed and coarse second-phase particles are precipitated. It becomes easy and the strength is slightly improved, but the bending workability is deteriorated. At the same time, the coarse second-phase particles promote roughening of the bent portion and promote die wear during press working. Accordingly, the total of one or more selected from the group consisting of Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B, and P as the third element group is 0 to 0 in total. It can contain 0.5 mass%, and it is preferable to contain 0.05-0.5 mass% in total.

<Second phase particles>
In the present invention, “second phase particles” refers to particles having a composition different from the component composition of the parent phase. The object of control in the present invention is a particle mainly composed of Cu and Ti that precipitates during various heat treatments to form a parent phase and a boundary, specifically, TiCu ₃ particles or a third element. Appears as Cu-Ti-X-based particles containing group component X (specifically, any of Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B and P) .

  In the present invention, the second phase particles are classified into two types, those having a particle size of 0.05 μm or more and 1.0 μm or less and those having a particle size exceeding 1.0 μm, and the average number density thereof is defined. The second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less are mainly precipitated during the aging treatment, and the second phase particles having a particle size of more than 1.0 μm are mainly precipitated before the aging treatment. It is believed that what remained was further grown during the aging treatment. The reason why the former particle size is set to 0.05 μm or more is that it is difficult to count too fine second-phase particles.

  Therefore, the average number density (Y) of the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less reflects the conditions in the aging treatment, and the average number of the second phase particles having a particle size of more than 1.0 μm. The density (X) reflects the heat treatment conditions up to the end of the solution treatment in addition to the conditions in the aging treatment.

  The number density (Y) of the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less decreases when the degree of aging treatment is reduced (eg, low temperature and short time), and the degree of aging treatment is increased (eg: It becomes larger when performed at high temperature for a long time. If Y is too small, it indicates that the degree of aging treatment is insufficient (sub-aging) and the required strength cannot be obtained. On the other hand, even if Y is too large, this indicates that the degree of aging treatment was excessive (overaging), and the aging treatment conditions under which the peak intensity is obtained are lowered and the bending workability is deteriorated.

In the titanium copper according to the present invention, the average number density (Y) of the second phase particles having a particle diameter of 0.05 μm or more and 1.0 μm or less observed by a microscopic cross section parallel to the rolling direction is 10 to 20 particles / μm. Controlling to ² is considered appropriate for obtaining a good balance between strength and bending workability, preferably 12 to 17 pieces / μm ^{2, and} more preferably 13 to 15 pieces / μm ² . As described above, this number density corresponds to the number density obtained in the case of over-aging conditions in the case of conventional titanium copper.

  Further, the distribution state of the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less is defined not only from the number density but also from the viewpoint of the area ratio of the second phase particles occupying the observation field at the time of cross-sectional inspection. can do. As described above, the area ratio of the second phase particles in the particle size range increases with the amount of precipitation, but a significant increase in the amount of precipitation adversely affects strength and bending workability. Therefore, there is a preferable area ratio for obtaining a good balance between strength and bending workability.

  According to the examination result of the present inventor, the area ratio of the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less observed by a speculum of a cross section parallel to the rolling direction is 4.0 to 15.0%. It is preferable that it is 5.0 to 9.0%.

  On the other hand, the number density (X) of the second phase particles having a particle size exceeding 1.0 μm is affected by the aging treatment in the same manner as Y, but it affects the heat treatment conditions before the aging treatment, particularly the final solution treatment conditions. receive. By appropriately performing the final solution treatment, the second phase particles precipitated in the previous step can be dissolved, but if the conditions of the solution treatment are inappropriate, the second phase particles remain. Or newly deposited. Since the second phase particles having a particle size exceeding 1.0 μm have a greater adverse effect on the strength and bending workability than those having a particle size of 1.0 μm or less, it is desirable that the second phase particles be as small as possible.

Therefore, in a preferred embodiment of the titanium-copper according to the present invention, the average number density (X) of the second phase particles having a particle size exceeding 1.0 μm observed by a microscopic cross section parallel to the rolling direction is 0.00. is 15 pieces / [mu] m ² or less, may be 0.1 or / [mu] m more preferably ² or less, for example 0.05 to 0.15 pieces / [mu] m ^2.

  In the present invention, the particle diameter of the second phase particles is defined as the diameter of the smallest circle surrounding the second phase particles when observed with the above-mentioned microscope.

<Strength reduction characteristics by heat treatment>
One of the interesting properties of the titanium copper according to the present invention is that the strength reduction after performing a predetermined heat treatment is larger than that of conventional titanium copper. This is because, as described above, a peak strength higher than that of conventional titanium copper can be obtained by performing a predetermined heat treatment that can cause spinodal decomposition in advance after the final solution and before cold rolling. In the case of titanium copper having the same composition, when a predetermined heat treatment is applied to both to develop the precipitation of the second phase particles, the strength decreases and the same bottom strength is obtained. For this reason, the titanium copper according to the present invention is greatly reduced in strength as compared with conventional titanium copper.

  Specifically, the titanium copper according to the present invention has a 0.2% yield strength (YS) of 400 MPa or more, preferably 450 MPa or more, more preferably 500 MPa when heated at a material temperature of 550 ° C. for 5 hours. For example, the pressure drops by 400 to 550 MPa.

<Crystal grain size>
In order to improve the strength and bending workability of titanium copper, the smaller the crystal grains, the better. Therefore, the preferable average crystal grain size is 30 μm or less, more preferably 20 μm or less, and still more preferably 10 μm or less. Although there is no restriction | limiting in particular about a minimum, In order to recrystallize uniformly without an unrecrystallized area | region, 3 micrometers or more are preferable. In the present invention, the average crystal grain size is represented by the equivalent circle diameter in the observation of the structure of the cross section parallel to the rolling direction by observation with an optical microscope or electron microscope.

<Characteristics of copper alloy according to the present invention>
In one embodiment, the copper alloy according to the present invention can have the following characteristics.
(A) The 0.2% proof stress in the rolling parallel direction is 950 MPa or more and less than 1000 MPa. (B) MBR / t, which is the ratio of the minimum radius (MBR) to the thickness (t) at which cracks do not occur in the Badway W bending test. Value 0.8-1.2

In another embodiment, the copper alloy according to the present invention can have the following characteristics.
(A) The 0.2% proof stress in the rolling parallel direction is 1000 MPa or more and less than 1050 MPa. (B) MBR / t, which is the ratio of the minimum radius (MBR) to the thickness (t) at which cracks do not occur in the Badway W bending test. Values are 1.2-1.7

In yet another embodiment, the copper alloy according to the present invention can have the following characteristics.
(A) The 0.2% proof stress in the rolling parallel direction is 1050 MPa or more and 1100 MPa or less. (B) MBR / t, which is a ratio of the minimum radius (MBR) to the plate thickness (t) at which cracks do not occur in the Badway W bending test. The value is 1.7 to 2.0

<Application>
The copper alloy according to the present invention can be provided as various copper products, such as plates, strips, tubes, rods and wires. The titanium copper according to the present invention is not limited, but can be suitably used as a material for electronic parts such as switches, connectors, jacks, terminals, relays and the like.

<The manufacturing method of the copper alloy which concerns on this invention>
Titanium copper according to the present invention can be produced by carrying out appropriate heat treatment and cold rolling, particularly in the final solution treatment and the subsequent steps. Below, a suitable manufacture example is demonstrated one by one for every process.

1) Ingot production Ingot production by melting and casting is basically performed in a vacuum or in an inert gas atmosphere. If the additive element remains undissolved during melting, it does not effectively act on strength improvement. Therefore, in order to eliminate undissolved residue, it is necessary to add a high melting point third element such as Fe or Cr, and after sufficiently stirring, hold for a certain period of time. On the other hand, since Ti is relatively easily dissolved in Cu, it may be added after the third element is dissolved. Therefore, Cu includes one or more selected from the group consisting of Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B, and P in total from 0 to 0.0. It is desirable to add so as to contain 50% by mass, and then add Ti so as to contain 2.0 to 4.0% by mass to produce an ingot.

2) Homogenization annealing and hot rolling Solidification segregation and crystallized material generated during ingot production are coarse, so it is desirable to make it as small as possible by dissolving it in the parent phase as much as possible by homogenization annealing. This is because it is effective in preventing bending cracks.
Specifically, after the ingot manufacturing process, it is preferable to perform hot rolling after heating to 900 to 970 ° C. and performing homogenization annealing for 3 to 24 hours. In order to prevent liquid metal embrittlement, it is preferable that the temperature is 960 ° C. or lower before and during hot rolling, and that the pass from the original thickness to 90% of the total rolling reduction is 900 ° C. or higher. And in order to raise | generate moderate recrystallization for every pass and to reduce the segregation of Ti effectively, it is good to implement the amount of rolling reduction for every pass at 10-20 mm.

3) First solution treatment It is then preferable to perform the solution treatment after appropriately repeating cold rolling and annealing. The reason why the solution treatment is performed in advance is to reduce the burden in the final solution treatment. That is, in the final solution treatment, it is not a heat treatment for dissolving the second phase particles, but is already in solution, so it is only necessary to cause recrystallization while maintaining that state. Just heat treatment. Specifically, the first solution treatment may be performed at a heating temperature of 850 to 900 ° C. for 2 to 10 minutes. In this case, it is preferable to increase the heating rate and the cooling rate as much as possible so that the second phase particles do not precipitate.

4) Intermediate rolling As the rolling reduction in the intermediate rolling before the final solution treatment is increased, the recrystallized grains in the final solution treatment can be controlled more uniformly and finely. Therefore, the rolling reduction of the intermediate rolling is preferably 70 to 99%. The rolling reduction is defined by {((thickness before rolling−thickness after rolling) / thickness before rolling) × 100%}.

5) Final solution treatment In the final solution treatment, it is desirable to completely dissolve the precipitates, but if heated to a high temperature until it completely disappears, the crystal grains tend to coarsen, so the heating temperature is the second phase. The temperature is around the solid solubility limit of the particle composition (the temperature at which the solid solubility limit of Ti becomes equal to the addition amount in the range where the addition amount of Ti is 2.0 to 4.0% by mass is about 730 to 840 ° C, For example, when the added amount of Ti is 3.2 mass%, it is about 800 ° C.). And if it heats rapidly to this temperature and a cooling rate is also made fast, generation | occurrence | production of coarse 2nd phase particle | grains will be suppressed. Therefore, typically, heating is performed at a temperature at which the solid solubility limit of Ti at 730 to 880 ° C. is the same as the addition amount, and more typically, the solid solubility limit of Ti at 730 to 880 ° C. is the same as the addition amount. It is heated to a temperature that is 0 to 20 ° C. higher, preferably 0 to 10 ° C. higher than the temperature that becomes.

  Moreover, the coarsening of a crystal grain can be suppressed when the heating time in the final solution treatment is shorter. The heating time can be, for example, 0.5 to 3 minutes, and typically 0.5 to 1.5 minutes. Even if the second phase particles are generated at this point, if they are finely and uniformly dispersed, they are almost harmless to strength and bending workability. However, since coarse particles tend to grow further in the final aging treatment, the number of second-phase particles at this point must be reduced as much as possible.

6) Aging treatment An aging treatment is performed following the final solution treatment. Conventionally, it was customary to perform cold rolling after the final solution treatment, but in order to obtain titanium copper according to the present invention, cold rolling is performed after the final solution treatment as described above. It is important to perform an aging treatment immediately without aging. Since the aging treatment is performed immediately after the solution treatment, there is little distortion that becomes the driving force for precipitation, and because the degree of heat treatment at which the peak intensity is obtained is at a point larger than conventional, the aging treatment is more than the conventional aging conditions. It should be done at a slightly high temperature. Specifically, heating is preferably performed at a material temperature of 400 to 500 ° C. for 0.5 to 24 hours, and more preferably 3 to 12 hours.

  The relationship between the material temperature and the heating time will be described in more detail. When the material temperature is 400 ° C. or higher and lower than 450 ° C., it is preferably heated for 1 to 24 hours, more preferably 7 to 12 hours. When the material temperature is 450 ° C. or higher and lower than 500 ° C., heating is preferably performed for 0.5 to 12 hours, and more preferably 3 to 7 hours.

7) Final cold rolling After the aging treatment, final cold rolling is performed. The strength of titanium copper can be increased by the final cold working. Specifically, the rolling reduction is 5% or more, preferably 10% or more, more preferably 15% or more. However, as the rolling reduction increases, the strength increases but the bendability deteriorates. Therefore, the rolling reduction is set to 40% or less, preferably 30% or less, more preferably 25% or less.

8) Annealing After the final cold rolling, annealing may be performed for the purpose of further improving the strength. Although the mechanism of further improving the strength by annealing after cold rolling has not been fully elucidated at present, it is considered that the development of the modulation structure by spinodal decomposition further proceeds. However, if the annealing is too strong, it will be over-aged and the strength will be lowered and the bendability will be deteriorated. As specific conditions for the annealing, it is preferable to perform the heating at a material temperature of 250 ° C. or more and 550 ° C. or less for 0.001 to 0.5 hours, and for a long time at a low temperature (for example, at a material temperature of 250 to 300 ° C. 0.01 to 0.25 hour heating), if it is high temperature for a short time (for example, 0.005 to 0.0075 hour heating at a material temperature of 500 to 550 ° C.), an intermediate temperature between the two (material temperature exceeding 300 ° C.) If it is less than 500 ° C.), it is more preferably carried out under the heating condition for 0.075 to 0.3 hours.

  A person skilled in the art will understand that steps such as grinding, polishing, and shot blast pickling for removing oxide scale on the surface can be appropriately performed between the above steps.

  Examples of the present invention will be described below together with comparative examples, but these examples are provided for better understanding of the present invention and its advantages, and are not intended to limit the invention.

Example 1 (Effect of manufacturing process on the structure and properties of titanium copper)
When manufacturing the copper alloy of the present invention example, Ti, which is an active metal, is added as the second component, so a vacuum melting furnace was used for melting. In addition, in order to prevent unexpected side effects due to mixing of impurity elements other than the elements defined in the present invention, raw materials having a relatively high purity were carefully selected and used.

  After adding Fe to Cu so that the composition contains 3.2% by mass of Ti and 0.2% by mass of Fe, and the balance is made of copper and inevitable impurities, Ti was added. After giving sufficient consideration to the retention time after the addition so that the additive element did not remain undissolved, these were injected into the mold in an Ar atmosphere to produce about 2 kg of ingot.

  After the homogenization annealing which heats at 950 degreeC with respect to the said ingot for 3 hours, it hot-rolled at 900-950 degreeC, and obtained the hot-rolled sheet of 10 mm in thickness. After descaling by chamfering, cold rolling was performed to obtain a strip thickness (2.0 mm), and a primary solution treatment was performed on the strip. The conditions for the primary solution treatment were heating at 850 ° C. for 10 minutes. Next, after cold rolling to an intermediate plate thickness (0.10 mm), the steel sheet was inserted into an annealing furnace capable of rapid heating, and the final solution treatment was performed under the conditions shown in Table 1. Subsequently, an aging treatment, cold rolling, and annealing were performed under the conditions described in Table 1. Before cold rolling, descaling was performed by pickling. In cold rolling, the sheet was rolled to a thickness of 0.075 mm. The aging treatment was performed in an inert gas (Ar) atmosphere, and the other heat treatment was performed in air.

About each obtained test piece, characteristic evaluation was performed on the following conditions.
<Strength>
A JIS No. 13B specimen was prepared using a press so that the tensile direction was parallel to the rolling direction. The specimen was subjected to a tensile test according to JIS-Z2241, and the 0.2% proof stress (YS) in the rolling parallel direction was measured.
<Bending workability>
In accordance with JIS H 3130, a W-bending test of Badway (the bending axis is the same direction as the rolling direction) was performed to measure the MBR / t value, which is the ratio of the minimum radius (MBR) at which cracks do not occur to the plate thickness (t).
<Number density of second phase particles>
By cutting the cross section parallel to the rolling direction with FIB, the cross section was exposed, and then the cross section was observed with SIM, and an observation visual field of 30 μm × 30 μm was photographed.
For each second phase particle, the diameter of the smallest circle surrounding the second phase particle is measured on the photograph, the second phase particle having a particle size of 0.05 μm or more and 1.0 μm or less, and a particle size exceeding 1.0 μm. The number density was divided into second phase particles, and the respective number densities Y and X were measured.
<Area ratio of second phase particles having a particle size of 0.05 μm to 1.0 μm>
By cutting the cross section parallel to the rolling direction with FIB, the cross section was exposed, and then the cross section was observed with SIM, and an observation visual field of 30 μm × 30 μm was photographed. In the observation field of view, second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less are marked, the area occupied by this is obtained by an image analyzer, and the average value of the five fields of view is calculated. The area ratio of the second phase particles of 0 μm or less was determined. Image analysis was performed by binarizing only the second phase particles having a particle size of 0.05 μm or more and 1.0 μm or less in white and other regions in black.
<Average crystal grain size>
The average crystal grain size is measured by cutting a cross section parallel to the rolling direction with FIB, exposing the cross section, observing the cross section with SIM, and counting the number of crystal grains per unit area. The average equivalent circle diameter was obtained. Specifically, a frame of 100 μm × 100 μm was created, and the number of crystal grains present in this frame was counted. Note that all the crystal grains crossing the frame were counted as ½. The average value of the area per crystal grain is obtained by dividing the frame area of 10,000 μm ² by the total. Since the diameter of the perfect circle having the area is the equivalent circle diameter, this was defined as the average crystal grain size.
<Strength reduction characteristics by heat treatment>
The obtained test piece was subjected to a heat treatment of heating for 5 hours at a material temperature of 550 ° C., and then the 0.2% yield strength (YS) was measured by the procedure described above to determine the degree of decrease in YS before and after the heat treatment. .

Invention Example No. 1 and Invention Example No. 1 2 differs depending on the presence or absence of annealing. No. In No. 1, since the annealing was performed after cold rolling, the strength further increased.
Invention Example No. 3 is Invention Example No. This is an example in which the aging treatment is performed on the high temperature and long time side as compared with 1, and the strength is increased.
Invention Example No. No. 4 is Invention Example No. This is an example in which the final solution treatment was performed on the high temperature and long time side as compared with 1, and the crystal grain size was increased. As a result, the present invention example is an invention example no. Although the balance of strength and bending workability is inferior compared to 1 to 3, the strength and balance in the examples of the present invention are superior to those in the comparative examples. . 5 or No. This can be understood by comparison with 6.
Invention Example No. Although 5 is an invention example, since the aging treatment time was short, the degree of precipitation of the second phase particles was lower than that of the other invention examples.
Comparative Example No. Reference numeral 1 is a conventional example. Since the aging treatment was performed after the cold rolling, the degree of precipitation of the second phase particles was lower than that of the inventive examples. Further, although the bottom strength was the same, the peak strength was low due to the difference in manufacturing conditions, so the amount of YS reduction due to heat treatment was small.
Comparative Example No. 2 is also a conventional example. Comparative Example No. In order to make the precipitation degree of the second phase particles higher than 1, the aging treatment was conducted in Comparative Example No. 1. When it was carried out for a long time at a temperature higher than 1, it was over-aged. Therefore, the amount of YS reduction due to heat treatment was further reduced.
Comparative Example No. No. 3 was subjected to an aging treatment immediately after the final solution treatment, but since it was performed under sub-aging conditions, the second phase particles were not sufficiently precipitated, and the amount of YS decrease due to the heat treatment was also small.
Comparative Example No. No. 4 was subjected to an aging treatment immediately after the final solution treatment, but because it was carried out under overaging conditions, the second phase particles precipitated excessively, and the amount of YS reduction due to heat treatment was small.
Comparative Example No. 5 is Comparative Example No. The solution treatment was performed at a temperature higher than 1 to increase the amount of solid solution that contributes to precipitation, but because of the conventional process, precipitation of the second phase particles in the aging treatment was insufficient. Therefore, the amount of YS reduction by heat treatment was small.
Comparative Example No. 6 is Comparative Example No. In order to increase the degree of precipitation of the second phase particles compared to 5, aging treatment was performed at a high temperature. However, this time, overaging has occurred, and the amount of YS reduction due to heat treatment has become even smaller.
Comparative Example No. 7 is Comparative Example No. In this example, the solution treatment temperature was further increased with respect to 5, the degree of precipitation of the second phase particles was low, and the crystal grain size grew too much.
Comparative Example No. No. 8 is Comparative Example No. In this example, the solution treatment temperature is set lower than 1. Due to the solution treatment, the second phase particles were not sufficiently dissolved but remained in a large amount, so that the precipitation degree of the second phase particles after the aging treatment became excessive. The crystal grain size was less than 1.0 μm.

Example 2 (Effect of composition on titanium copper properties)
Ti was added after adding a predetermined third element to Cu so that titanium copper having the additive element concentrations shown in Table 3 was obtained. After giving sufficient consideration to the retention time after the addition so that the additive element did not remain undissolved, these were injected into the mold in an Ar atmosphere to produce about 2 kg of ingot.

  After the homogenization annealing which heats at 950 degreeC with respect to the said ingot for 3 hours, it hot-rolled at 900-950 degreeC, and obtained the hot-rolled sheet of 10 mm in thickness. After descaling by chamfering, cold rolling was performed to obtain a strip thickness (2.0 mm), and a primary solution treatment was performed on the strip. The conditions for the primary solution treatment were heating at 850 ° C. for 10 minutes. Then, after cold rolling to an intermediate plate thickness (0.10 mm), the steel sheet was inserted into an annealing furnace capable of rapid heating and subjected to the final solution treatment under the conditions shown in Table 4. Next, aging treatment, cold rolling, and annealing were performed under the conditions described in Table 4. Before cold rolling, descaling was performed by pickling. In cold rolling, the sheet was rolled to a thickness of 0.075 mm. The aging treatment was performed in an inert gas (Ar) atmosphere, and the other heat treatment was performed in air.

  Table 5 shows the results of the evaluation of the properties of the obtained test pieces in the same manner as in Example 1. It can be seen that the intended effect of the present invention can be obtained even if the alloy composition is changed within the specified range.

Claims (8)

It contains 2.0 to 4.0% by mass of Ti, and one or more of Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B, and P as the third additive element Is a copper alloy consisting of the remaining copper and unavoidable impurities, and having a particle size of 0.05 μm or more and 1.0 μm or less as observed by a microscopic cross section parallel to the rolling direction The average number density (Y) of the second phase particles is 10 to 20 particles / μm ² , and 0.2% proof stress (YS) decreases by 400 MPa or more when heat treatment is performed at a material temperature of 550 ° C. for 5 hours. Copper alloy. ^2. The copper alloy according to claim 1, wherein the average number density (X) of the second phase particles having a particle diameter exceeding 1.0 μm observed by a spectroscopic cross section parallel to the rolling direction is 0.15 particles / μm ² or less.   3. The copper according to claim 1, wherein the area ratio of the second phase particles having a particle diameter of 0.05 μm or more and 1.0 μm or less observed by a spectroscopic cross section parallel to the rolling direction is 4.0 to 15.0%. alloy.   The copper alloy according to any one of claims 1 to 3, wherein the average crystal grain size is 3 to 30 µm.   It contains 2.0 to 4.0% by mass of Ti, and one or more of Mn, Fe, Mg, Co, Ni, Cr, V, Nb, Mo, Zr, Si, B, and P as the third additive element Is a method for producing a copper alloy comprising a total of 0 to 0.5% by mass, the balance being copper and unavoidable impurities, and the temperature at which the solid solubility limit of Ti at 730 to 880 ° C. is the same as the addition amount As above, after the final solution treatment performed under the condition of heating for 0.5 to 3 minutes, the aging treatment and the cold rolling performed under the condition of heating at the material temperature of 400 to 500 ° C. for 0.5 to 24 hours are sequentially performed. Production method.   The manufacturing method of Claim 5 which further implements annealing on the conditions heated for 0.001-0.5 hours at material temperature 250-550 degreeC after the said cold rolling.   The electronic component provided with the copper alloy as described in any one of Claims 1-4.   The electronic component according to claim 7, which is a connector.