JP3511648B2 - Method for producing high-strength Cu alloy sheet strip - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength Cu alloy for forming electrical and electronic parts, such as connectors and lead frames, which are more excellent in bending workability than conventional ones. The present invention relates to a method of manufacturing a thin strip (plate and strip). 2. Description of the Related Art Cu-Ni-Si based Cu alloys have long been used as electrical and electronic component materials such as connectors and lead frames because they have both strength and electrical conductivity. In the production process of the Cu-Ni-Si-based Cu alloy sheet strip, generally, the ingot is quenched by water cooling after hot rolling, face milling is performed, then cold rolling and annealing are repeated, and cold rolling before finishing is performed. And then subjecting to a finishing treatment, wherein the finishing treatment is a step of performing a solution treatment at 650 to 900 ° C., a step of performing finish cold rolling at a rolling reduction of about 15 to 75%, and an aging treatment at 350 to 550 ° C. (See Japanese Patent Application Laid-Open No. 5-59505). In recent years, the fabrication of such small-sized electrical and electronic components such as connectors and lead frames requires extreme bending. However, Cu-Ni-Si-based Cu manufactured by the above-described conventional manufacturing process is used.
When extreme bending is performed using alloy thin strips to produce electrical and electronic components such as small connectors and lead frames, there have been problems such as cracks occurring in the extremely bent portions. [0004] Accordingly, the present inventors have proposed:
Without impairing properties such as conductivity, tensile strength and elongation,
As a result of conducting research to obtain a high-strength Cu alloy thin strip excellent in bending workability that does not crack even after extreme bending work, the Cu alloy ingot was quenched by water cooling after hot rolling, After the cold rolling and annealing are repeated, the thin strip that has been subjected to cold rolling before finish rolling is subjected to solution treatment, subjected to primary aging treatment, subjected to finish cold rolling, and then subjected to primary aging treatment temperature. It has been found that when the secondary aging treatment is performed at a higher temperature, a Cu alloy sheet strip having better bending workability than before can be obtained. [0005] The present invention has been made based on such findings, and is based on the mass of Ni: 2 to 5% and Si: 0.
3 to 1%, Zn: 0.1 to 1%, Mg: 0.001 to
0.05%, Sn: 0.05-1%, the remainder being C
hot-rolling a water-cooled Cu alloy ingot consisting of u and unavoidable impurities, and having a composition in which the contents of sulfur (S) and carbon (C) as unavoidable impurities are S: 20 ppm or less and C: 20 ppm or less, respectively. After quenching, face milling, and then repeated cold rolling and annealing,
In the method for producing a high-strength Cu alloy strip that is subjected to cold rolling before finishing and then subjected to finishing, the finishing is performed by first aging after solution treatment, then cold-rolling after finishing and then secondary aging. And the above-mentioned secondary aging treatment is characterized by a method for producing a high-strength Cu alloy sheet strip performed at a relatively higher temperature than the primary aging treatment. [0006] The solution treatment in the above finishing treatment is carried out by 7
It is preferable to perform quenching under conditions of holding at 00 to 900 ° C. for 5 seconds to 60 minutes, preferably performing finish cold rolling in a range of 5 to 35%, and performing secondary aging in a range of 350 to 650.
C. for 0.01 to 600 minutes. These conditions are included in the range of conventional Cu—Ni—Si based Cu alloy production conditions.
In the production method of the u-alloy sheet strip, 0.5 to 12 at 300 to 600 ° C between the solution treatment and the finish cold rolling step.
It is characterized in that a primary aging process of a condition for keeping time is inserted and that the primary aging process is performed at a relatively lower temperature than the secondary aging process. The reasons for limiting the composition of the Cu alloy used in the production method of the present invention are as follows. (A) Ni and Si These two components combine to form an intermetallic compound composed mainly of Ni 2 Si which is finely dispersed in the base material and has an action of improving the strength. Is Ni: 2%
If the content is less than 5% and the Ni content is more than 5%, the electrical conductivity is reduced, and the Si content is less than 1%. If it exceeds, the hot workability decreases, so the contents are respectively Ni: 2 to 5% and Si: 0.3 to 1%.
It was decided. (B) Zn The Zn component has an effect of improving the heat-peeling resistance of the solder. However, if the content is less than 0.1%, the desired effect cannot be obtained in the above-mentioned effect. Exceeds 2%, the electrical conductivity sharply decreases, so the content was determined to be 0.1 to 2%. (C) Mg The Mg component has an effect of improving hot workability.
If the content is less than 0.001%, the desired effect of improving hot workability cannot be obtained, while if the content exceeds 0.05%, no further improvement effect is exhibited. Was determined to be 0.001 to 0.05%. (D) Sn The Sn component has the effect of improving the adhesion strength to the epoxy resin as a sealing material for semiconductor devices and the like, but if its content is less than 0.05%, the desired effect is obtained. No improvement effect can be obtained, and on the other hand, if the content exceeds 1%, the conductivity will be reduced.
%. (E) S and C as unavoidable impurities Generally, this type of Cu alloy contains 30 ppm or less of S and C as unavoidable impurities, respectively, unless the content of each of these S and C is 20 ppm or less. Since the desired effect of improving the adhesion strength by Sn cannot be obtained, the content of each of S and C is set to 20 ppm.
Must be restricted to: In the manufacturing method of the present invention, after a Cu alloy assembly having the above-mentioned composition is obtained, hot rolling is followed by rapid cooling by water cooling, face milling, cold rolling and annealing as in the conventional manufacturing method. The pre-finishing rolling is repeatedly performed, and is characterized by successively performing the following finishing treatment. The reasons for limiting the conditions of each treatment included in the finishing treatment are as follows. (F) Solution treatment This treatment is carried out to suppress precipitation of Ni silicide as much as possible and to avoid coarsening of recrystallized grains. The treatment is carried out for a long time when the treatment temperature is low, and for a long time when the treatment temperature is high. Is carried out in such a manner as to be held for a short time, but even if it is held at less than 700 ° C. for more than 60 minutes, the Ni silicide exceeding the solid solubility limit coarsens, which is not preferable. On the other hand, at a temperature exceeding 950 ° C. Holding for less than 5 seconds is not preferable because solid solution of Ni silicide is insufficient. Therefore, solution treatment conditions are 700-950 ° C.
For 5 seconds to 60 minutes. (G) Primary aging treatment After performing the solution treatment described above to suppress precipitation of Ni silicide as much as possible and to prevent coarsening of recrystallized grains, fine and large amounts of Ni silicide are formed before finish cold rolling. Precipitating and performing finish cold rolling in a state where the strength is improved, the bending workability is greatly improved. At that time, even if it is held at less than 300 ° C for more than 12 hours, Since the effect of improving the bending workability cannot be sufficiently obtained even if the holding time is longer than 0.5 hour, the primary aging condition is 300 to 600 ° C.
It was set to hold for 0.5 to 12 hours. (H) Finish Cold Rolling Finish cold rolling is carried out to further enhance the effect of the secondary aging treatment. When the rolling reduction is less than 5%, the effect of improving the strength is small, and the rolling reduction is 35%. When the rolling ratio exceeds 5 mm, cracks occur at the time of bending.
It was set to ~ 35%. (I) Secondary aging treatment Ni-silicide is finely precipitated to improve the strength. Particularly, in order to improve the bending workability, the temperature is relatively higher than the primary aging treatment temperature. Since it is preferable to perform the treatment, 350-650 ° C, 0.01-600
Minute conditions. Example 1 A Cu alloy having a composition (% by mass) shown in Table 1 was prepared by a semi-continuous casting method using a conventional low-frequency dielectric melting furnace.
An ingot having dimensions of 150 mm, width: 500 mm, and length: 3000 mm was formed. This ingot was subjected to hot rolling at a rolling start temperature of 950 ° C. to form a hot-rolled sheet having a thickness of 11 mm. After water cooling, the upper and lower surfaces of the hot-rolled sheet were chamfered to a thickness of 10 mm. This was repeatedly cold-rolled, annealed and pickled, and cold-rolled before finishing to produce thin plates having the thicknesses shown in Tables 2 to 4. Table 2 obtained by cold rolling before the above finishing
After holding a thin plate having a thickness shown in Table 4 in a salt bath furnace at a temperature shown in Tables 2 to 4 for an hour, immediately subjected to a water-cooled solution treatment, pickled, polished, and then non-oxidized. In the furnace, subjected to primary aging treatment at the temperature x time shown in Tables 2 to 4,
Then, after finish cold rolling at the rolling ratios shown in Tables 2 to 4, followed by a secondary aging treatment of temperature x time shown in Tables 2 to 4, the method of the present invention 1 to 20 and Comparative Methods 1 to 7 were performed. Furthermore, the comparative method 8 omitting the secondary aging treatment and the conventional method 1 without the primary aging treatment
Was carried out. For the Cu alloy thin plates manufactured according to the methods 1 to 20 of the present invention, the comparative methods 1 to 8 and the conventional method 1, tensile strength, elongation, bending workability and electrical conductivity were measured by the following methods, and the measurement results were obtained. The results are shown in Tables 5 to 8. (A) JIS samples taken of tensile strength and elongation measured parallel to the rolling direction (shown by BW in Tables 5 to 8) and at right angles (shown by GW in Tables 5 to 8)
The tensile strength and elongation were measured using a No. 13 B test piece. (B) Measurement of conductivity Measured according to JIS H0505. (C) Measurement of bending workability According to CES M0002-5, load: 9807N,
Inner bending radius R: 0 to 0.75 mm (multiple of 0.075 mm), the bending axis is parallel and perpendicular to the rolling direction, the central bending part of W bending is observed with a 75-fold optical microscope, and cracks occur Of the inner bending radius (R) / plate thickness (t) was measured. The smaller the value of R / t thus measured, the better the bending workability, and the larger the value, the worse the bending workability. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7] [Table 8] From the contents and results shown in Tables 2 to 8, the Cu obtained by the present invention methods 1 to 20 which had been subjected to the finishing treatment of the steps of solution treatment → primary aging treatment → finish cold rolling → secondary aging treatment was used. It can be seen that all of the alloy sheets have excellent bending workability as compared with the Cu alloy sheet obtained by the conventional method 1 which has been subjected to the finishing treatment of solution treatment → finish cold rolling → aging treatment. However, Comparative Methods 1 to 7 in which the same finishing treatment was performed at a temperature and a rolling ratio outside the conditions of the present invention, and Comparative Method 8 in which the secondary aging treatment was omitted, had tensile strength, elongation, and bending. It can be seen that at least one of the processability and the conductivity has an unfavorable value. Example 2 A hot rolled sheet having a thickness of 11 mm was prepared from Cu alloy ingots having different component compositions shown in Table 9 under the same conditions as in Example 1, and after cooling with water, the upper and lower surfaces of the hot rolled sheet were removed. Beveling and thickness: 10mm,
This was repeatedly subjected to cold rolling, annealing and pickling, and a pre-finish rolled sheet having a thickness of 1.0 mm was prepared by pre-finish rolling. The pre-finished rolled sheet is subjected to a solution treatment of cooling at a temperature of 800 ° C. for 10 seconds and then water cooling, and then a temperature of 450 ° C.
Primary aging treatment at 3 ° C. for 3 hours, and then subject the Cu alloy thin plate subjected to the primary aging treatment to finish cold rolling at a rolling reduction of 15%.
Thickness: 0.15 by secondary aging treatment
A Cu alloy thin plate having a thickness of mm was prepared, and the methods 21 to 23 of the present invention and the comparative methods 10 to 21 were performed. Inventive Methods 21 to 23, Comparative Methods 10 to 21
The tensile strength, elongation, bending workability and electrical conductivity were measured on the Cu alloy thin plate obtained in the same manner as in Example 1, and the measurement results are shown in Tables 10 and 11. Other characteristics are also shown in the remarks column of Tables 10 and 11. [Table 9] [Table 10] [Table 11] From the results shown in Tables 9 to 11, Ni: 2 to 5%, Si: 0.3 to 1%, Zn:
0.1-2%, Mg: 0.001-0.05%, Sn:
0.05 to 1%, the balance consisting of Cu and unavoidable impurities, and the content of sulfur (S) and carbon (C) as unavoidable impurities is S: 20 ppm or less, respectively.
C: Cu-Ni-Si having a composition of 20 ppm or less
It can be seen that the Cu alloy thin plates obtained by the methods 21 to 23 of the present invention using a system Cu alloy have superior properties as compared with the comparative methods 10 to 21 which are out of the conditions of the present invention. As described above, according to the present invention, it is possible to manufacture a Cu alloy sheet having excellent bending workability without deteriorating the strength and conductivity. Severe bending can be performed using the manufactured Cu alloy sheet strip, and a more compact connector,
Electric and electronic components such as lead frames can be manufactured, which can greatly contribute to industrial development.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazunori Kikukawa 128-7 Ogimachi, Aizuwakamatsu-shi, Fukushima Prefecture Mitsubishi Shindoh Copper Co., Ltd. Wakamatsu Works (56) References JP-A-3-56649 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C22F 1/00-3/02 C22C 9/06

Claims (1)

(57) in [Claims 1. A mass%, Ni: 2~5%, Si : 0.
3 to 1%, Zn: 0.1 to 2%, Mg: 0.001 to
0.05%, Sn: 0.05-1%, the remainder being C
u and inevitable impurities, and the content of sulfur (S) and carbon (C) as inevitable impurities is S:
C having a composition of 20 ppm or less and C: 20 ppm or less
The u alloy ingot cooled water after hot rolling, subjected repeatedly annealing and cold rolling After scalped, then subjected to finish before cold rolling, in the manufacturing method of the Cu alloy thin strip is subjected to finishing process subsequent The above finishing treatment is performed at 700 to 900 ° C for 5 seconds to 60 minutes.
After solution heat treatment of the water-cooling conditions After lifting, 300
A primary aging treatment is performed at 600 ° C. for 0.5 to 12 hours , followed by finish cold rolling at a rolling reduction of 5 to 35% , followed by 0.01 to 600 minutes at 350 to 650 ° C.
A method for producing a high-strength Cu alloy sheet strip, comprising a step of performing a secondary aging treatment under conditions of holding , and performing the secondary aging treatment at a relatively higher temperature than the primary aging treatment.