TWI475117B - High strength titanium and copper - Google Patents

Description

High strength titanium copper

The present invention relates to a high-strength titanium copper which is preferably a spring material for electronic parts such as an FPC connector or an automatic focus camera module.

In recent years, the miniaturization of electronic devices represented by portable terminals and the like has been increasing. Therefore, the narrow pitch and low height of the connectors used therefor are remarkable. The smaller the connector, the narrower the pin width, and the smaller the folded shape, so that the member to be used is required to have a higher strength to obtain the necessary elasticity. In this respect, since the copper alloy containing titanium (hereinafter referred to as "titanium copper") has a relatively high strength, it is the most excellent in the copper alloy in terms of stress relaxation characteristics, and thus has been used as a signal for particularly required strength since the prior art. Component for system terminals.

Titanium copper type age hardening type copper alloy. If a supersaturated solid solution of Ti as a solute atom is formed by solution treatment, and a heat treatment is carried out at a low temperature for a relatively long period of time, the Ti concentration in the parent phase is caused by spinodal decomposition. The periodic variation, that is, the modulation structure is developed, and the strength is improved. At this time, the point of the problem is that the strength and the bending workability are opposite. In other words, when the strength is increased, the bending workability is impaired, and conversely, when the bending workability is emphasized, the desired strength cannot be obtained. In general, the more cold The rolling reduction ratio of the rolling is increased, and the dislocation density is increased as the amount of the difference is increased. Therefore, the nucleation point which contributes to precipitation increases, and the strength after the aging treatment can be improved. However, if the rolling reduction ratio is excessively increased, the bending workability is deteriorated. Therefore, achieving both strength and bending workability has become a problem.

Therefore, there has been proposed a technique for achieving both the strength and bending workability of titanium copper from the viewpoints of the following, and the viewpoint is to add a third element such as Fe, Co, Ni, or Si (Patent Document 1); The concentration of the impurity element group to be solid-solved is such that the second phase particles (Cu-Ti-X-based particles) are precipitated in a specific distribution form to improve the regularity of the modulation structure (Patent Document 2); The density of the micro-additive element and the second-phase particle which are effective in refining the crystal grain (Patent Document 3); and the grain refinement (Patent Document 4).

In the case of titanium copper, there is a poorly matched β phase (TiCu ₃ ) and a well-matched β′ phase (TiCu ₄ ) relative to the α phase as the parent phase, and the β phase adversely affects the bending workability. On the other hand, the uniformity and fine dispersion of the β' phase contributes to both the strength and the bending workability, and the titanium copper in which the β' phase is finely dispersed while suppressing the β phase is proposed (Patent Document 5) .

It is also proposed to control the crystal alignment by focusing on the crystal orientation to satisfy the I{420}/I ₀ {420}>1.0 and I{220}/I ₀ {220}≦3.0, thereby improving the strength and bending. Workability and stress relaxation resistance (Patent Document 6).

However, for any of the titanium coppers described in the above prior documents, the manufacturing method is based on the melt casting of the ingot → homogenization annealing → hot rolling → (reverse annealing and cold rolling) → final solution treatment → cold The order of rolling→aging treatment is limited, and there is a limit to the improvement of characteristics.

In this case, in recent years, an attempt has been made to reverse the order of the cold rolling and the aging treatment after the final solution treatment, that is, to replace the aging treatment with the cold rolling sequence. Finally, the relaxation annealing is performed to improve the bending workability (Patent Document 7). According to this document, by using such a manufacturing method, the difference in the discharge density of the obtained titanium copper increases. Further, the difference density is indirectly evaluated based on the half-height width of the X-ray diffraction intensity peak of the {220} crystal plane in the rolling surface, and the X-ray diffraction intensity peak from the {220} crystal plane of the rolling surface is specified. The half-height width, β{220}, and the half-height width of the X-ray diffraction intensity peak from the {220} crystal plane of the pure copper standard powder, β ₀ {220}, satisfy the following formula: 3.0≦β{220}/β ₀ { 220}≦6.0.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-231985

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2004-176163

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2005-97638

[Patent Document 4] Japanese Laid-Open Patent Publication No. 2006-265611

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2006-283142

[Patent Document 6] Japanese Laid-Open Patent Publication No. 2008-308734

[Patent Document 7] Japanese Patent Laid-Open Publication No. 2012-062575

As described above, most of the conventional techniques strive to improve the characteristics from the two aspects of strength and bending workability, but there are also those in the connector that hardly require bending workability. For example, the FPC connector or the autofocus camera module does not perform bending processing, so there is no need to improve bending workability. On the other hand, the connector is exposed to a high temperature environment during use, but if the titanium copper is long When exposed to high temperature conditions, permanent deformation (aging) occurs, and the function as a spring material is degraded. No sufficient research has been done on this content.

Accordingly, it is an object of the present invention to provide a high-strength titanium copper which is preferably used as an electrically conductive spring material for use in electronic components such as FPC connectors or camera modules.

The inventors of the present invention have been striving to investigate the relationship between 0.2% proof stress and aging of titanium and copper, and the relationship between crystal orientation and aging, and found that the 0.2% guaranteed stress is high and EBSD (Electron Back Scatter Diffraction) In the analysis of the crystal orientation during the measurement, when the KAM value is 1.5 to 3.0, the aging resistance at the time of high temperature exposure is particularly improved. The present invention has been completed in the light of the above findings and is defined by the following.

One aspect of the present invention is a titanium copper containing 2.0 to 4.0% by mass of Ti and containing 0 to 0.5% by mass in total selected from the group consisting of Fe, Co, Mg, Si, Ni, Cr, Zr, Mo, and V. One or more of the groups consisting of Nb, Mn, B, and P are used as the third element, and the remainder is composed of copper and unavoidable impurities, and the KAM value is 1.5 to 3.0 in the crystal orientation analysis at the time of EBSD measurement. .

In one embodiment of the titanium copper of the present invention, the 0.2% proof stress is 1100 MPa or more.

Another aspect of the present invention is a copper extending article comprising the titanium copper of the present invention.

Still another aspect of the present invention is an electronic component comprising the titanium copper of the present invention.

One embodiment of the electronic component of the present invention is an autofocus camera module.

According to still another aspect of the present invention, an autofocus camera module includes a lens, a spring member that elastically presses the lens to an initial position in an optical axis direction, and an electromagnetic drive The means for generating the electromagnetic force against the elastic force of the spring member to drive the lens in the optical axis direction; and the spring member is the titanium copper of the present invention.

High-strength titanium copper, which is preferred as a conductive spring material for electronic components such as camera modules, is available.

1‧‧‧Auto Focus Camera Module

2‧‧‧Y yoke

3‧‧‧ lens

4‧‧‧ magnet

5‧‧‧ bracket

6‧‧‧ coil

7‧‧‧Base

8‧‧‧Frame

9a‧‧‧Spring member on the upper side

9b‧‧‧lower spring member

10a, 10b‧‧‧ cover

1 is a cross-sectional view showing the autofocus camera module of the present invention.

2 is an exploded perspective view of the autofocus camera module of FIG. 1.

3 is a cross-sectional view showing the operation of the autofocus camera module of FIG. 1.

Fig. 4 is a schematic view showing a method of measuring the amount of aging.

(1) Ti concentration

In the titanium copper of the present invention, the Ti concentration is 2.0 to 4.0% by mass. The titanium-copper system is solid-dissolved in the Cu matrix by solution treatment, and the fine precipitates are dispersed in the alloy by aging treatment, thereby increasing the strength and electrical conductivity.

When the Ti concentration is less than 2.0% by mass, the precipitation of precipitates becomes insufficient and the desired strength cannot be obtained. When the Ti concentration exceeds 4.0% by mass, the workability is deteriorated, and the material is easily broken at the time of rolling. When the balance between strength and workability is considered, the preferred Ti concentration is 2.5 to 3.5% by mass.

(2) The third element

In the titanium copper of the present invention, one or more selected from the group consisting of Fe, Co, Mg, Si, Ni, The third element in the group consisting of Cr, Zr, Mo, V, Nb, Mn, B, and P can further increase the strength. However, when the total concentration of the third elements exceeds 0.5% by mass, the workability is deteriorated, and the material is easily broken at the time of rolling. Therefore, the third element may be contained in an amount of from 0 to 0.5% by mass in total, and in consideration of the balance between strength and workability, it is preferred to contain one or more of the above elements in a total amount of from 0.1 to 0.4% by mass.

(3) 0.2% guaranteed stress

In the embodiment of the titanium copper of the present invention, the 0.2% proof stress in the direction parallel to the rolling direction can reach 1100 MPa or more. The 0.2% proof stress of the titanium copper of the present invention is 1200 MPa or more in the preferred embodiment, and 1300 MPa or more in the more preferred embodiment.

The upper limit of the 0.2% guaranteed stress is not particularly limited in terms of the strength of the target of the present invention, but it is due to the time and cost, and if the titanium concentration is increased in order to obtain high strength, it is hot rolled. The risk of breakage at that time is such that the 0.2% guaranteed stress of the titanium copper of the present invention is generally 2000 MPa or less, generally 1600 MPa or less, and more generally 1500 MPa or less.

In the present invention, the 0.2% proof stress in the direction parallel to the rolling direction of the titanium copper is measured in accordance with JIS Z2241 (Metal Material Tensile Test Method).

(4) KAM value

In one embodiment of the titanium copper of the present invention, the KAM (Kernel Average Misorientation) value is 1.5 to 3.0. The KAM value indicates the difference in orientation between adjacent measurement points in the crystal grain, and can be calculated by the following method: crystal orientation analysis in the EBSD (Electron Back Scatter Diffraction) measurement, and the use of the EBSD Analytical software (Example: OIM (Orientation Imaging Microscopy) manufactured by TSL Solutions) Analysis) Determine the difference in orientation within the grain. In the present invention, in order to determine the stability of the measurement results, the field of view of 200 μm × 200 μm at five points was measured, and the average value was calculated and used as a measured value.

In the present invention, the following measurement conditions are used as the EBSD measurement.

(a) SEM conditions

‧ Beam condition: Acceleration voltage 15kV, irradiation current amount 5×10 ^-8 A

‧Work Distance: 25mm

‧ Observation field of view: 200μm × 200μm

‧ observation surface: rolling surface

‧ Pretreatment of the observation surface: Electrolytic polishing was carried out in a solution of phosphoric acid 67% + sulfuric acid 10% + water at 15 V × 60 seconds to expose the structure

(b) EBSD conditions

‧Measurement program: OIM Data Collection

‧Data analysis program: OIM Analysis

‧Step width: 0.5μm

The KAM value is an indirect evaluation of the index of poor row density. The KAM value decreases as the difference in density is lowered, and conversely, it tends to rise as the difference in density increases. As a result of intensive studies, the inventors have found that when the KAM value is from 1.5 to 3.0, the strength is high and the aging resistance at high temperature is good. If the KAM value is higher than the upper limit, the aging resistance at the time of high temperature exposure tends to be deteriorated, and if it is lower than the lower limit, the strength is liable to lower, which is not preferable. The KAM value is preferably from 1.8 to 3.0, more preferably from 2.1 to 3.0.

(5) Thickness of titanium copper

In general, as the thickness of the metal material becomes thinner, the aging resistance is lowered, but in the present invention In one embodiment of titanium copper, the thickness may be 1.0 mm or less, and in a general embodiment, the thickness may be 0.02 to 0.8 mm, and in a more general embodiment, the thickness may be 0.05 to 0.5 mm.

(6) Use

The titanium copper of the present invention can be processed into various copper-exposed products such as plates, strips, tubes, rods and wires. The titanium copper of the present invention is not limited, and can be preferably used as a switch, a connector (especially a FPC connector of a fork type that does not require excessive bending workability), an autofocus camera module, a jack, a terminal, and a relay. Materials such as electronic parts.

In one embodiment, the autofocus camera module includes: a lens; a spring member that elastically presses the lens to an initial position in an optical axis direction; and an electromagnetic driving means that generates an electromagnetic force that resists an elastic force of the spring member. The above lens can be driven in the optical axis direction. Electromagnetic driving means can be exemplified a yoke of a cylindrical shape; a coil received inside the inner peripheral wall of the yoke; and a magnet surrounding the coil and housed inside the outer peripheral wall of the yoke.

1 is a cross-sectional view showing an example of an autofocus camera module of the present invention, FIG. 2 is an exploded perspective view of the autofocus camera module of FIG. 1, and FIG. 3 is a cross-sectional view showing the operation of the autofocus camera module of FIG. .

The auto focus camera module 1 has: a yoke 2 having a cylindrical shape; a magnet 4 attached to the outer wall of the yoke 2; a bracket 5 having a lens 3 at a central position; a coil 6 mounted to the bracket 5; and a base 7 Mounted with a yoke 2; frame 8 supporting the base 7; 2 spring members 9a, 9b equal to the upper and lower support brackets 5; and 2 caps 10a, 10b covering the spring members 9a, 9b Above and below. The two spring members 9a and 9b are the same article, and are clamped from the upper and lower sides in the same positional relationship and support the bracket 5, and function as a power supply path to the coil 6. The carrier 5 is moved upward by applying a current to the coil 6. In addition, in the present specification, the upper and lower terms are appropriately used, and when it is displayed above and below in FIG. 1, the upper position indicates the positional relationship from the camera toward the subject.

The yoke 2 is a magnet such as soft iron, and is formed such that the upper surface portion is closed. The zigzag has a cylindrical shape and has a cylindrical inner wall 2a and an outer wall 2b. to The inner surface of the outer wall 2b of the glyph is attached (and then) with a ring-shaped magnet 4.

The bracket 5 has a cylindrical structure having a bottom surface portion and is formed of a synthetic resin or the like, and supports the lens at a central position, and the pre-formed coil 6 is mounted on the outer side of the bottom surface. The yoke 2 is fitted and assembled to the inner peripheral portion of the base 7 of the rectangular resin molded article, and the entire yoke 2 is fixed by the frame 8 of the resin molded article.

Each of the spring members 9a and 9b is fixed by the frame 8 and the base 7 respectively, and the slit portions of the inner peripheral portion which are spaced apart by 120° are fitted to the bracket 5, and are thermally caulking. ) and so on.

The spring member 9b and the base 7 and the spring member 9a and the frame 8 are fixed by thermal caulking or the like, and the cover 10b is attached to the bottom surface of the base 7, and the cover 10a is attached to the upper portion of the frame 8, respectively. The spring member 9b is sandwiched and fixed between the base 7 and the cover 10b, and the spring member 9a is sandwiched and fixed between the frame 8 and the cover 10a.

The lead wire on one side of the coil 6 is extended upward by a groove provided in the inner circumferential surface of the bracket 5, and is welded to the spring member 9a. The other lead is extended downward through a groove provided in the bottom surface of the bracket 5, and is welded to the spring member 9b.

The spring members 9a, 9b are plate springs of the titanium copper foil of the present invention. It has elasticity and elastically presses the lens 3 to the initial position in the optical axis direction. At the same time, the spring members 9a, 9b also function as a power supply path to the coil 6. One of the outer peripheral portions of the spring members 9a, 9b protrudes It functions as a feed terminal to the outside.

The cylindrical magnet 4 is magnetized in the radial (diameter) direction to form The inner wall 2a, the upper surface portion, and the outer wall 2b of the word-shaped yoke 2 are magnetic paths of the path, and the coil 6 is disposed in a gap between the magnet 4 and the inner wall 2a.

The spring members 9a and 9b have the same shape and are attached in the same positional relationship as shown in Figs. 1 and 2, so that the axial shift when the bracket 5 is moved upward can be suppressed. Since the coil 6 is formed by press-molding after being wound, the accuracy of the final outer diameter is improved, and it can be easily disposed in a specific narrow gap. The bracket 5 is in contact with the susceptor 7 at the lowest position, and is in contact with the yoke 2 at the uppermost position. Therefore, the bracket 5 is provided with a contact mechanism in the vertical direction to prevent falling off.

Fig. 3 is a cross-sectional view showing a state in which a current is applied to the coil 6 and the carriage 5 having the lens 3 is moved upward in the autofocus application. When a power source is applied to the feed terminals of the spring members 9a and 9b, a current flows through the coil 6 and an upward electromagnetic force acts on the carrier 5. On the other hand, the restoring force of the two connected spring members 9a and 9b acts on the bracket 5 downward. Therefore, the upward movement distance of the bracket 5 is a position at which the electromagnetic force and the restoring force are balanced. Thereby, the amount of movement of the carriage 5 can be determined by the amount of current applied to the coil 6.

The upper side spring member 9a supports the upper surface of the bracket 5, and the lower side spring member 9b supports the lower surface of the bracket 5, so that the restoring force acts on the upper surface and the lower surface of the bracket 5 equally downward, so that The axis shift of the lens 3 is suppressed to be small.

Therefore, when the bracket 5 is moved upward, it is not necessary to guide with a flange or the like. Since there is no sliding friction caused by the guiding, the amount of movement of the bracket 5 is purely governed by the balance between the electromagnetic force and the restoring force, so that the movement of the lens 3 with smoothness and precision can be achieved. Thereby, automatic focusing with less lens oscillation is achieved.

In addition, although the magnet 4 has been described as a cylindrical shape, the magnet 4 is not limited thereto, and may be divided into three or four portions and magnetized in the radial direction, and attached and fixed to the yoke 2 The inner surface of the outer wall 2b.

(7) Manufacturing method

The titanium copper of the present invention can be produced, inter alia, by the final solution treatment and subsequent heat treatment and cold rolling in the subsequent steps. Hereinafter, a preferred manufacturing example will be described in order for each step.

<Ingot manufacturing>

The manufacture of ingots obtained by melting and casting is carried out essentially in a vacuum or in an inert gas atmosphere. If there is a melting residue of the additive element in the melting, the improvement in strength does not play an effective role. Therefore, in order to eliminate the melt residue, the third element having a high melting point such as Fe or Cr must be sufficiently stirred after the addition, and thereafter kept for a certain period of time. On the other hand, Ti is relatively easy to be melted in Cu, so it may be added after the third element is melted. Therefore, it is preferable to select a group consisting of Fe, Co, Mg, Si, Ni, Cr, Zr, Mo, V, Nb, Mn, B, and P in a total amount of 0 to 0.5% by mass. One type or two or more types are added to Cu, and then Ti is added in an amount of 2.0 to 4.0% by mass to produce an ingot.

<Homogenizing annealing and hot rolling>

Since solidification segregation or coarse crystals are generated at the time of ingot production, it is preferably reduced by solidification in the mother phase by homogenization annealing, and is eliminated as much as possible. The reason for this is that it is effective for preventing bending fracture. Specifically, it is preferable to carry out homogenization annealing for 3 to 24 hours after heating to 900 to 970 ° C after the ingot production step, and then perform hot rolling. In order to prevent the brittleness of the liquid metal, it is preferably set to 960 ° C or lower before hot rolling and hot rolling, and the pass from the original thickness to the overall rolling reduction ratio of 90% is set to 900 ° C or higher.

<First solution treatment>

Thereafter, it is preferred to carry out the first solution treatment after cold rolling and annealing are appropriately repeated. The reason for the solid solution preliminarily here is to reduce the burden in the final solution treatment. That is, the final solution treatment is not a heat treatment for solid-solubilizing the second phase particles, and since it is solid-solved, it is only necessary to recrystallize while maintaining this state, so that a slight heat treatment is performed. can. Specifically, the first solution treatment system may be carried out for 2 to 10 minutes by setting the heating temperature to 850 to 900 °C. It is preferable to accelerate the temperature increase rate and the cooling rate at this time as much as possible, and the second phase particles are not precipitated here. Furthermore, the first solution treatment may not be performed.

<intermediate rolling>

The higher the rolling reduction ratio in the intermediate rolling before the final solution treatment, the more the recrystallized grains in the final solution treatment can be controlled to be uniform and fine. Therefore, the rolling reduction ratio of the intermediate rolling is preferably 70 to 99%. The rolling reduction ratio is defined by {((thickness before rolling - thickness after rolling) / thickness before rolling) × 100%}.

<Final solution treatment>

In the final solution treatment, it is preferred that the precipitate is completely solid-solved. However, if it is heated to a high temperature until it completely disappears, the crystal grains are easily coarsened. Therefore, the heating temperature is set as the solid solution limit of the second phase particle composition. The temperature in the vicinity (the amount of Ti added is in the range of 2.0 to 4.0% by mass, and the solid solution limit of Ti is about 730 to 840 ° C which is the same as the amount of addition, for example, 800 when the addition amount of Ti is 3.0% by mass. °C or so). Further, if the temperature is rapidly heated to this temperature and the cooling rate is also accelerated by water cooling or the like, the generation of coarse second phase particles is suppressed. Therefore, it is generally heated to a temperature of 730 to 840 ° C Ti solid solution is the same temperature as the addition of -20 ° C ~ +50 ° C temperature, more commonly heated to higher than 730 ~ 880 ° C Ti solid solution Limited to the same amount as the added amount The temperature of 0 to 30 ° C is preferably heated to a temperature of 0 to 20 ° C.

Further, the shorter the heating time in the final solution treatment, the more the coarsening of crystal grains can be suppressed. The heating time can be, for example, 30 seconds to 10 minutes, and can be generally set to 1 minute to 8 minutes. That is, it is convenient to generate the second phase particles at this time point, and as long as it is finely and uniformly dispersed, the strength and the bending workability are hardly damaged. However, since the coarse crystal grains tend to grow further in the final aging treatment, even if the second phase particles are generated at this time point, they must be reduced and reduced as much as possible.

Specifically, the average crystal grain size after the final solution treatment is preferably controlled within a range of 2 to 30 μm, more preferably controlled within a range of 2 to 15 μm, and more preferably controlled within a range of 2 to 10 μm. Inside. The average crystal grain size was obtained by exposing the structure of the cross section parallel to the rolling direction by electrolytic polishing, and then photographing the observation field of view of 100 μm × 100 μm by an electron microscope (SEM). Then, based on JISH0501, the average crystal grain size in the direction perpendicular to the rolling direction and the average grain size in the direction parallel to the rolling direction were determined by a dicing method, and the average value of the two was defined as the average crystal grain size.

<pre-aging>

After the final solution treatment, pre-aging treatment is carried out. Conventionally, cold rolling is usually performed after the final solution treatment, but in order to obtain the titanium copper of the present invention, it is important to perform the pre-aging treatment without performing cold rolling after the final solution treatment. The pre-aging heat treatment is performed at a lower temperature than the aging treatment in the next step, and the aging resistance at high temperature exposure and the strength of the titanium copper are remarkably remarkable by continuously performing the pre-aging heat treatment and the following aging treatment. Improve the advantages. The pre-aging treatment is preferably carried out in an inert environment such as Ar, N ₂ or H ₂ to suppress the generation of the surface oxide film.

The above-mentioned advantages are difficult to obtain, whether the heating temperature in the pre-aging treatment is too low or too high. According to the research results of the present inventors, it is preferred to heat at a material temperature of 150 to 250 ° C for 10 to 20 hours, more preferably at a material temperature of 160 to 230 ° C for 10 to 18 hours, and more preferably at 170 to 200. Heat at °C for 12~16 hours.

<Aging treatment>

After the pre-aging treatment, the aging treatment is performed. It can also be cooled to room temperature temporarily after pre-aging treatment. In consideration of the production efficiency, it is preferable to carry out the aging treatment continuously by raising the temperature to the aging treatment temperature without cooling after the pre-aging treatment. Regardless of the method, the characteristics of the obtained titanium copper are the same. However, since the purpose of pre-aging is to uniformly precipitate the second phase particles in the subsequent aging treatment, cold rolling should not be performed during the pre-aging treatment and the aging treatment.

The pre-aging treatment causes a little precipitation of the solid solution titanium in the solution treatment, so the aging treatment should be carried out at a lower temperature than the conventional aging treatment, preferably at a material temperature of 300 to 450 ° C for 0.5 to 20 hours. More preferably, the material is heated at a temperature of 350 to 440 ° C for 2 to 18 hours, and more preferably for 3 to 15 hours at a material temperature of 375 to 430 ° C. The aging treatment is preferably carried out in an inert environment such as Ar, N ₂ or H ₂ for the same reason as the pre-aging treatment.

Although the invention is not intended to be limited by theory, it is considered that the characteristics of titanium copper are remarkably improved by continuously performing pre-aging heat treatment and aging treatment for the following reasons. The fine second phase particles are uniformly deposited by applying a pre-aging heat treatment. Thereafter, by performing cold rolling, the difference in density is increased, so that a higher strength is known. When the pre-aging heat treatment is not applied, the second phase particles are coarsened or become uneven, so that even if cold rolling is performed, a sufficient difference in the discharge density cannot be obtained, and the strength becomes insufficient.

<final cold rolling>

The final cold rolling is performed after the above aging treatment. The strength of titanium copper can be increased by the final cold working. In order to obtain the high strength sought by the present invention, the rolling reduction ratio is 55% or more, preferably 60% or more, and more preferably 90% or more. However, when the rolling reduction ratio is too high, the manufacturability is lowered. Therefore, the rolling reduction ratio is preferably 99.9% or less, more preferably 97% or less, and still more preferably 95% or less.

<Swelling Annealing>

From the viewpoint of improving the aging resistance at the time of high temperature exposure, it is preferable to carry out the relaxation annealing after the final cold rolling. The reason for this is that the difference rows are rearranged by performing relaxation annealing. The conditions of the relaxation annealing may be conventional conditions, but if the relaxation annealing is excessively performed, the coarse particles are precipitated and the strength is lowered, which is not preferable. The relaxation annealing is preferably performed at a material temperature of 200 to 600 ° C for 10 to 600 seconds, more preferably at 250 to 550 ° C for 10 to 400 seconds, and more preferably for 300 to 500 ° C for 10 to 200 seconds. .

Further, it will be understood by those skilled in the art that steps such as grinding, polishing, shot blasting, and the like for removing scale on the surface can be appropriately performed between the above steps.

[Examples]

The embodiments of the present invention are shown below in conjunction with the comparative examples, which are intended to provide a better understanding of the present invention and its advantages, and are not intended to limit the invention.

The alloy containing the alloy component shown in Table 1 and the remainder consisting of copper and unavoidable impurities was used as an experimental material, and the influence of the alloy composition, the KAM value, and the manufacturing conditions on the 0.2% proof stress and the aging at high temperature exposure was investigated.

First, 2.5kg of electrolytic copper is melted by a vacuum melting furnace, as shown in Table 1. After the third ratio is added to the blending ratio, Ti is added to the blend ratio shown in the table. The holding time after the addition was also sufficiently considered so as not to cause the molten residue of the additive element, and then injected into the mold in an Ar environment, and about 2 kg of the ingot was separately produced.

The ingot was subjected to homogenization annealing at 950 ° C for 3 hours, and then hot rolled at 900 to 950 ° C to obtain a hot rolled sheet having a thickness of 15 mm. After the surface is removed by rust removal, cold rolling is performed to form a strip thickness (1 to 8 mm), and the first solution treatment using the strip is performed. The conditions of the first solution treatment were set to be heated at 850 ° C for 10 minutes, and then water-cooled. Then, according to the conditions of the rolling reduction rate and the product thickness in the final cold rolling described in Table 1, the rolling reduction ratio is adjusted and the intermediate cold rolling is performed, and then inserted into the annealing furnace which can be rapidly heated to carry out the final solid solution. The treatment is followed by water cooling. The heating condition at this time is the temperature at which the solid solution limit of the material temperature Ti is the same as the addition amount (about 800 ° C at a Ti concentration of 3.0% by mass, about 730 ° C at a Ti concentration of 2.0% by mass, and a Ti concentration of 4.0 at a Ti concentration of 2.0% by mass. The mass % is about 840 ° C), as shown in Table 1. Then, the pre-aging treatment and the aging treatment were continuously performed in the Ar environment under the conditions described in Table 1. That is, no cooling was performed after the pre-aging treatment. After derusting by pickling, final cold rolling was carried out under the conditions described in Table 1, and finally, the test pieces of the inventive examples and the comparative examples were prepared by performing relaxation annealing under the respective heating conditions shown in Table 1. The pre-aging treatment, the aging treatment, or the relaxation annealing may be omitted depending on the test piece.

The following samples were evaluated for the manufactured product samples.

(a) 0.2% guaranteed stress

A JIS 13B test piece was produced using a tensile tester, and a 0.2% proof stress in a direction parallel to the rolling direction was measured in accordance with the above measurement method.

(b) KAM value

The KAM value was determined by using the above-described measurement method using OIM-Analysis manufactured by TSL Solutions.

(c) Aging after exposure to high temperature (permanent deformation rate)

A short strip sample having a width of 10 mm is selected in such a manner that the length direction becomes a parallel direction of rolling, as shown in Fig. 4, one end of the sample is fixed, and the punching machine that processes the front end into a knife edge moves at 1 mm/min. The speed is pressed against the position from the fixed end L, and the initial strain (d) corresponding to the stress (σ ₀ ) of 1000 MPa (≒102 kg/mm ² ) is applied to the sample according to the following formula 1.

Equation 1: d=2/3×L×σ ₀ /(E.t)

d = initial strain (mm)

L = gauge length (mm)

σ ₀ = stress (kg/mm ² )

E = Young's modulus (kg/mm ² )

t = plate thickness (mm)

Then, in a state where strain is applied, the film is heated at 250 ° C for 30 minutes, and the puncher is returned to the initial position and unloaded, and the amount of permanent deformation (δ) is obtained to obtain a permanent deformation ratio (= δ / d × 100).

Further, the average crystal grain size of the semi-finished product after the final solution treatment was measured by the above-described measuring method using an electron microscope (XL30 SFEG manufactured by Philips).

(examine)

The test results are shown in Table 1. In Inventive Examples 1 to 18, it was found that the 0.2% proof stress was higher than 1100 MPa, and the permanent deformation rate was suppressed to be low.

On the other hand, in Comparative Example 1, the crystal grains were coarsened due to the excessive temperature of the final solution treatment, KAM The values are also outside the scope of the present invention, so the 0.2% guaranteed stress and the permanent deformation rate are inferior to the inventive examples.

In Comparative Example 2, the mixing of the non-recrystallized region and the recrystallized region was caused by the final solution treatment temperature being too low, and the KAM value was outside the range of the present invention. Therefore, the permanent deformation rate is inferior to the invention.

In the comparative example 3, the invention described in Japanese Laid-Open Patent Publication No. 2012-0625757 is considered. Since the strength improvement is insufficient because the pre-aging treatment is not performed, the KAM value is also outside the scope of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 4, although the pre-aging treatment was performed, the heating temperature was too low, and the strength improvement was insufficient, and the KAM value was outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 5, since the heating temperature at the time of pre-aging was too high, it became overaged and precipitated coarse particles, and the KAM value was also outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 6, since the aging treatment was not performed, the phase decomposition was insufficient and the strength was insufficient, and the KAM value was also outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 7, the aging treatment was carried out. However, since the heating temperature was too low, the strength improvement was insufficient, and the KAM value was outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 8, since the heating temperature was too high at the time of aging treatment, it was over-aged and precipitated coarse particles, and the KAM value was also outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 9, since the reduction ratio at the time of final cold rolling was too low, the strength was insufficient, and the KAM value was also outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 10, since the relaxation annealing was not performed, the KAM value was outside the range of the present invention. Therefore, the permanent deformation rate is inferior to the invention.

Comparative Example 11 was subjected to relaxation annealing, but since the heating temperature was low, the KAM value was outside the scope of the present invention. Therefore, the permanent deformation rate is inferior to the invention.

Comparative Example 12 was subjected to relaxation annealing, but since the heating temperature was too high, the difference was eliminated, and the KAM value was also outside the scope of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 13, since the amount of the third element added was too large, the film was broken during hot rolling, so that the test piece could not be produced.

In Comparative Example 14, since the Ti concentration was too low, the strength was insufficient, and the KAM value was also outside the range of the present invention. Therefore, the 0.2% proof stress and the permanent deformation rate are both inferior to the invention examples.

In Comparative Example 15, since the Ti concentration was too high and cracking occurred during hot rolling, the production of the test piece could not be performed.

Claims (6)

A titanium copper containing 2.0 to 4.0% by mass of Ti and containing a total of 0 to 0.5% by mass selected from the group consisting of Fe, Co, Mg, Si, Ni, Cr, Zr, Mo, V, Nb, Mn, B, One or more of the groups consisting of P and the third element are the third element, and the remainder is composed of copper and unavoidable impurities, and the KAM value is 1.5 to 3.0 in the crystal orientation analysis at the time of EBSD measurement. For example, the titanium copper of the first aspect of the patent application, wherein the above 0.2% guaranteed stress is 1100 MPa or more. A copper-clad product having titanium copper of claim 1 or 2. An electronic component having titanium copper of claim 1 or 2. For example, the electronic component of claim 4, wherein the electronic component is an autofocus camera module. An autofocus camera module having a lens; a spring member elastically pressing the lens to an initial position in an optical axis direction; and an electromagnetic driving means for generating an electromagnetic force against the elastic pressure of the spring member The lens is driven in the axial direction; and the spring member is titanium copper in the first or second aspect of the patent application.