KR100885824B1 - Copper alloy having superior hot workability and method for producing same - Google Patents

Abstract

assignment

The copper alloy for electronic components which is excellent in strength, electroconductivity, and excellent hot workability without impairing bending workability is provided.

Resolution

Ni: 1.0%-2.0%, P: 0.10%-0.50% by mass ratio, Ni and P content ratio Ni / P: 4.0 or more and 6.5 or less, Cr: 0.03% or more and 0.45% or less, or B : 0.005-0.070 mass% and remainder are copper alloys which consist of Cu and an unavoidable impurity, Furthermore, you may contain 0.01% or more and 1.0% or less in total of 1 or more types of Sn and In, Preferably it is 700 Mpa or more of tensile strength High-strength high-conductivity copper alloys for electronic components with high electrical conductivity of 40% IACS or higher and excellent hot workability and high strength.

Copper alloy

Description

Copper alloy with excellent hot workability and manufacturing method {COPPER ALLOY HAVING SUPERIOR HOT WORKABILITY AND METHOD FOR PRODUCING SAME}

BRIEF DESCRIPTION OF THE DRAWINGS The external photograph of the sample edge part after the hot rolling test in Example 3 of this invention.

It is an external photograph of the sample edge part after the hot rolling test in the comparative example 8.

It is an external photograph of the sample edge part after the hot rolling test in the comparative example 9. FIG.

It is an external photograph of the sample edge part after the hot rolling test in the comparative example 10.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2000-273562

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a copper alloy excellent in hot workability for high-strength, high-conductivity electronic device components, particularly in copper alloys for small and highly integrated semiconductor device leads and terminal connectors, without particularly impairing bending workability. It is related with the copper alloy for electronic components which is excellent in electroconductivity and excellent in hot workability.

Copper and copper alloys are widely used in electronic components such as connectors and lead terminals, and for flexible circuit boards, and are widely used for various purposes. The improvement of a characteristic (strength, bending workability, electroconductivity) is calculated | required.

In addition, with the high integration of ICs, many semiconductor devices having high power consumption are used, and the lead frame material of semiconductor devices has Cu-Ni-Si-based, Cu-Fe-P, Cu-Cr- having good heat dissipation (conductivity). Precipitated alloys such as Sn and Cu-Ni-P have been used. The Cu-Ni-P-based alloy is reinforced by fine precipitation of a Ni-P-based compound, but Patent Document 1 describes an alloy having strength, conductivity, and stress relaxation resistance by adjusting the amount of Ni, P, and Mg components in the alloy. It is reported that it was obtained.

In general, in the casting of copper alloys, for example, continuous or semicontinuous casting, the ingot is exothermed by a mold, and the inside is subjected to some time except for a few mm of the surface layer. Solidify. At this time, in the cooling process after solidification and after solidification, the alloying elements contained in excess of the limit are crystallized out or precipitated into grain boundaries and grains. Copper alloys containing 1.0% or more of Ni and 0.2% or more of P have the advantage of high strength and high electrical conductivity, but at room temperature, since the copper alloy contains much of the dissolved Ni-P component in the Cu matrix phase, ingots are produced. In general, the Ni-P compound is crystallized or precipitated in the grain boundary. In addition, since the Ni-P-based compound crystallized or precipitated at the grain boundary of the Cu-Ni-P-based alloy has a lower melting point than the Cu of the parent phase, the solidification of these copper alloys becomes nonuniform, resulting in internal deformation and the stress and external force. This causes breakage in the Ni-P-based compound portion, causing cracks in the casting and cooling steps. In addition, since the Ni-P-based compound is softened or liquefied before the mother phase even during the heating of the hot rolling, cracks are similarly generated.

However, since the composition of Cu-Ni-P type alloy of patent document 1 is 0.01 to 1.0% of Ni and 0.01 to 0.2% of P, the said problem was not specifically conscious.

It is an object of the present invention to provide a Cu-Ni-P-based alloy which prevents cracking during casting, cooling, hot working heating or hot working, and has excellent hot ductility and good hot workability.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM The present inventors searched in order to achieve the said objective, and discovered that Cu-Ni-P type alloy which has the outstanding hot workability, the outstanding strength, and electroconductivity was obtained by specifying the following structure.

In the copper alloy, the present invention contains Ni: 1.0% or more and 2.0% or less (in the present specification,% indicating a component ratio is defined as mass%), P: 0.10% or more and 0.50% or less, and the content ratio of Ni and P is included. Ni / P: 4.0 or more and 6.5 or less, Cr: 0.03% or more and 0.45% or less, B: 0.005 to 0.070%, and the balance is excellent in hot workability, wherein the balance consists of Cu and unavoidable impurities. Preferably, the present invention relates to a copper alloy for high strength high-conductivity electronic devices excellent in hot workability, having a tensile strength of 700 MPa or more and a conductivity of 40% IACS or more. When one or more types of Sn and In are contained in the component composition in an amount of 0.01% or more and 1.0% or less, the tensile strength is preferably at least 750 MPa and the conductivity is at least 40%.

Best Mode for Carrying Out the Invention

Next, the reason which limited the numerical range of the component composition of a copper alloy in this invention is demonstrated with the action.

[Ni amount]

Ni has the effect of ensuring the strength and heat resistance of the alloy, and precipitates a Ni-P-based compound with P described later to contribute to the increase in the strength of the alloy. However, if the content is less than 1.0%, the desired strength cannot be obtained. On the other hand, if the Ni content exceeds 2.0%, the hot workability is lowered and the bending workability and conductivity of the product are remarkable. Moreover, it is also undesirable to increase the area ratio of the large Ni-P-based precipitates. When the sum (Ni + P) of the content of Ni and P exceeds 2.5%, the crystallization amount of coarse particles increases, and precipitation in the aging treatment is remarkable, making it difficult to control the precipitation of fine Ni-P having a size of 50 nm or less. Lose. Therefore, the Ni content of the alloy of the present invention is 1.0% to 2.0%, preferably 1.1 to 1.8%.

[P amount]

P precipitates a compound with Ni and improves the strength and heat resistance of the alloy. If the P content is less than 0.10%, the precipitation of the compound is insufficient, so that the desired strength cannot be obtained. On the other hand, when P content is contained exceeding 0.50%, hot workability will fall and the fall of electroconductivity will become remarkable. Moreover, it is also undesirable to increase the area ratio of the large Ni-P-based precipitates. Therefore, P content of the alloy of this invention is 0.1%-0.5%, Preferably it is 0.2-0.4%.

[Ni / P ratio]

Even if the content of Ni and P is within the above limited range, when the content ratio Ni / P of Ni and P deviates from the appropriate stoichiometric composition ratio of the Ni-P compound, that is, less than 4.0, the amount of solid solution of P increases. In addition, when it exceeds 6.5, the amount in which Ni is dissolved is increased, and the decrease in electrical conductivity is remarkable, which is not preferable. Therefore, Ni / P ratio of the alloy of this invention is 4.0 or more and 6.5 or less, Preferably it is 4.5-6.0.

[Size and Area Ratio of Ni-P Precipitates]

If the long diameter of the Ni-P-based precipitate is a (nm) and the short diameter is b (nm), the precipitate before a final cold rolling is subjected to the rolling deformation (η) = 2 or more, and the precipitate is copper. It is re-used in the inside, and lowers electrical conductivity, and is not preferable. On the other hand, the precipitate whose a before final cold rolling is 20 nm or more is hard to be reusable even in the rolling process with a process deformation ((eta)) = 2 or more, and exists as 10 nm or more precipitate. The precipitates of 20 nm or more have a small change in size before and after rolling, and in particular, the precipitates having a long diameter (a) of greater than 50 nm before rolling maintain a long diameter of more than 50 nm after rolling. Since it becomes too large, the strengthening of precipitation and the strengthening of processing are not obtained.

In addition, the long diameter (a) and the short diameter (b) cut the alloy bath before the final cold rolling at a thickness right angle in parallel in the rolling direction, and use the image analysis device to determine the cross-sectional image of all the precipitates having a long diameter (a) of 5 nm or more. It is an average value of each of the long and short diameters of all the precipitates measured. In addition, when the plate | board thickness before rolling is set to t0 and the plate | board thickness after rolling is set to t, the process deformation ((eta)) is represented by (eta) = ln (t0 / t).

From the above, the size of the Ni-P-based precipitate before the final cold rolling of the alloy of the present invention is preferably a long diameter (a) of 20 nm to 50 nm.

In addition, when the aspect ratio of a precipitate is represented by a / b, when a / b exceeds 5, when a rolling process of (eta) = 2 or more is carried out, a precipitate will be redissolved in copper and electrical conductivity will fall. Therefore, the aspect ratio (a / b) of the precipitate is preferably 1 to 5, more preferably 1 to 3.

In order to prevent the fall of strength and electrical conductivity, Preferably, after a final cold rolling, a is 10 nm-50 nm, and a / b is 1-5.

However, since it is difficult to make all precipitates into the preferable ranges of said a and a / b, the ratio with respect to all the precipitates of the precipitate which falls into the said a and a / b range becomes important. Therefore, when the ratio of the total area of the precipitates in the preferred range of a and a / b to the total area of all the precipitates in the alloy is the area ratio (C), the area ratio (C) of the present invention is preferably 80% or more.

The case where area ratio (C) is less than 80% is a case where many precipitates exceeding 50 nm or precipitates below 20 nm exist. For example, precipitates with a exceeding 50 nm or crystals generated during melt casting do not have a solid solution by heating or solution treatment before hot rolling, and there are many 1000-nm or more Ni-P particles (crystals) remaining. At this time, since the dispersion interval of the fine precipitates having a size of 20 to 50 nm, which contributes to the strength improvement, is large, the desired strength due to work hardening in rolling is not obtained. On the other hand, since the precipitate whose a is less than 20 nm is re-used by the rolling process, the fall of electrical conductivity becomes remarkable.

[Cr amount]

Generally, when the cooling rate at the time of solidification of Cu-Ni-P-based alloy is slow, for example, when the cooling rate of 1100 ° C to 950 ° C is less than 30 ° C / min, the Ni-P-based compound is concentrated and coarsened to the grain boundary. It is not preferable because it is crystallized with.

Cr suppresses crystallization or precipitation of the Ni-P-based compound to the grain boundary during the solidification of the Cu-Ni-P-based alloy, the cooling process after the solidification, and the heating of the hot working, thereby improving the hot workability of the alloy. However, if the content is less than 0.03%, the effect of improving hot workability is not obtained. On the other hand, if Cr is contained in excess of 0.45%, compounds such as Ni-P-Cr and Cr-P may be generated during dissolution or solidification. , Cr crystals are generated. These Cr-containing compounds and crystals are not dissolved in the Cu matrix phase by the solution treatment, and therefore the Ni-P-based compound precipitated by the aging treatment decreases, resulting in a decrease in the strength of the alloy. In addition, compounds such as Ni-P-Cr and Cr-P remain in the product as inclusions having a diameter of 5 μm or more in the product, and remain in the product, and the surface defects of the product, the origin of cracks during bending, and the origin of defects during plating treatment. This is undesirable because it becomes. Therefore, Cr content of the alloy of this invention is 0.03%-0.45% or less, Preferably it is 0.05%-0.30%.

It is not preferable that inclusions such as Ni-P-Cr compounds and Cr-P compounds having a long diameter of 5 µm or more are present. Preferably, the number of inclusions exceeding 50 µm in length is 0 per 1 mm 2 and 5 to 5 in diameter. The number of inclusions with 50 micrometers is 100 or less per mm <2>, More preferably, the number of inclusions with long diameter of 5-50 micrometers is 50 or less per mm <2>. In addition, the long diameter of the precipitate of the said Ni-P-Cr compound and Cr-P compound is measured similarly to the long diameter of the Ni-P type | system | group precipitate.

[B amount]

It is possible to improve hot workability even if B is added instead of Cr. B suppresses crystallization or precipitation of the Ni-P-based compound to the grain boundary during the solidification of the Cu-Ni-P-based alloy, the cooling process after the solidification, and the heating of the hot working, thereby improving the hot workability of the alloy. However, if the content is less than 0.005%, the effect of improving hot workability cannot be obtained. On the other hand, if B is contained in excess of 0.070%, compounds such as Ni-P-B and B-P are generated during dissolution or solidification as inclusions. Since these B-containing compounds are usually crystallized or precipitated along with grain size and coarsening, and are not dissolved in the Cu matrix by the solution treatment, the Ni-P-based compound precipitated by the aging treatment decreases, It causes a decrease in the strength of the alloy. In addition, compounds such as Ni-PB and BP remain in the product as inclusions having a diameter of 5 μm or more in the product, and are not preferable because they are surface defects of the product, the origin of cracks during bending, and the origin of defects during plating. not. Therefore, B content of the alloy of this invention is 0.005%-0.070% or less, Preferably it is 0.007%-0.060%.

[Includes]

The term "inclusion" of the present invention means a crystallized substance having a Ni-PB compound, a BP compound, or the like, which is crystallized or precipitated into grain boundaries and / or crystal grains in a Cu-Ni-P-based alloy, and is crystallized or precipitated into crystal grains. It does not contain a fine Ni-P-based compound. The long diameter of an inclusion means the average long diameter of an inclusion of 5 micrometers or more in rolling parallel cross section.

If inclusions exceeding 50 µm in long diameter are present, it becomes a starting point of cracks during bending and deteriorates the bending workability of the product. Therefore, the copper alloy of the present invention preferably has a number of inclusions exceeding 50 μm in long diameter per 0 mm 2. In addition, when an inclusion having a long diameter of 5 to 50 µm is present, the amount of B contained in the inclusion is increased, and the effect of suppressing crystallization of the Ni-P-based compound, which is the purpose of adding B, to the grain boundary is not obtained. Therefore, the copper alloy of the present invention preferably has a number of inclusions having a long diameter of 5 to 50 µm and 100 or less, more preferably 50 or less per 1 mm 2.

[Sn, In amount]

Both Sn and In amounts have the effect of improving strength mainly by solid solution strengthening without significantly reducing the conductivity of the alloy. Therefore, if necessary, one or more of these metals are added. If the content is less than 0.01% in total amount, the effect of strength improvement by strengthening solid solution is not obtained. On the other hand, if 1.0% or more is added in total amount, the alloy conductivity And the fall of bending workability becomes remarkable. For this reason, the amount of Sn and In added alone or in combination of two or more kinds is 0.01% to 1.0%, preferably 0.05% to 0.8% in total. In addition, these elements are intentionally added in the present invention, and are not regarded as unavoidable impurities.

[O amount]

O is easy to react with Cr in an alloy, and when O exists in an oxide state in an alloy, the effect of adding Cr is not obtained. In addition, P and B are also easy to oxidize, and in particular, when P is oxidized, Ni-P-based precipitates are reduced, leading to a decrease in strength. Therefore, O content of the alloy of this invention is 0.0050% or less, Preferably it is 0.0030% or less.

[Tensile strength and conductivity]

The copper alloy of this invention is excellent in hot workability, and also has excellent electroconductivity, tensile strength, and bending workability. Preferably the tensile strength of the copper alloy of this invention is 700 Mpa or more, More preferably, it is 750 Mpa or more, and the upper limit is about 950 Mpa normally. The conductivity is preferably 40% IACS or more, more preferably 45% IACS or more, and the upper limit is usually about 65% IACS.

[Cooling rate at solidification and size of inclusions]

Cu-Ni-P-based alloys satisfying the above requirements of the present invention are typically employed in the manufacture of ingot casting, hot rolling, solution treatment, intermediate cold rolling, aging treatment, final cold rolling, strain removal Although it can manufacture by selecting heating temperature, time, a cooling rate, rolling degree, etc. suitably for annealing etc., in the Cu-Ni-PB type alloy which added 0.005-0.070% of B, it is the continuous or semi-continuous which is normally performed The solidification rate in the casting varies depending on the apparatus and the method employed in the solidification step, and in the case of periodontal type or the like which does not employ cooling homogenization means, there is a difference between the outside and the inside of the ingot. For example, in the case of periodontal formula in which molten copper is poured into a steel mold (φ700 × h1500 mm) to solidify, a cooling rate of 1100 ° C. to 950 ° C. is about 1 ° C./min.

In the casting of the copper alloy of the present invention, the solidification temperature range is preferably 1100 ° C to 950 ° C, and when the cooling rate is slow in this cooling temperature range, the Ni-PB-based and / or PB-based compound coarsens in the solidification step. It is easy to produce | generate easily, and there exists a possibility that the hot ductility improvement by B addition may not be seen.

The correlation shown below was confirmed in the number and hot ductility of the inclusion which has the said Ni-P-B type and / or P-B type compound as a main component. In the result of measurement of the inclusions of the sample obtained by heating the ingot having a cooling rate of 1100 ° C. to 950 ° C. of less than 20 ° C./min at 850 ° C. for 1 hour in the casting and solidifying steps, the inclusions having a long diameter of 5 to 50 μm. When the number was 100 or more per 1 mm 2, or when the number of inclusions exceeding 50 μm in long diameter was 1 or more per 1 mm 2, cracks occurred in the hot rolling at 850 ° C. in the alloy to which B was added in a predetermined amount. Therefore, the cooling rate of 1100 ° C to 950 ° C in the casting and solidification step is preferably 20 ° C / min or more. In order not to deteriorate the bending workability of the alloy, in order to suppress coarse precipitation of the Ni-PB-based compound and the PB-based compound, the cooling rate of 1100 ° C to 950 ° C in the casting and solidification step is 30 ° C / min or more. This is preferred. Moreover, the cooling rate exceeding 1500 degree-C / min is unpreferable since the supply of molten metal to a solidification shrinkage part does not become timely, and the defect by a shrinkage hole increases.

The solidification temperature range is 1100 ° C to 950 ° C even in the case of casting the copper alloy of the present invention in which Cr is added, and when the cooling rate is slow in this cooling temperature range, the Ni-P-based and / or Ni-P-Mg-based compounds It is easy to produce | generate coarse at a solidification stage, and there exists a possibility that the improvement of hot ductility by addition of Cr may not be seen.

EXAMPLE

Cu-Ni-P-Cr based alloys (Table 1)

Preparation of the sample:

The main raw material is electric copper or oxygen-free copper, with nickel (Ni), 15% P-Cu master alloy (P), 10% Cr-Cu master alloy (Cr), tin (Sn), and indium (In) as secondary raw materials. It melt | dissolved in vacuum or argon atmosphere in the high frequency melting furnace, and cast it in the 45 x 45 x 90 mm ingot using the cast iron mold. Ingots were subjected to the hot rolling test, and ingots in which cracks did not occur due to hot rolling were performed in the order of hot rolling and solution treatment, aging treatment, intermediate cold rolling, aging treatment, final cold rolling, and strain removal annealing. And a flat plate having a thickness of 0.15 mm. The various test pieces of the obtained board | plate material were extract | collected, and the test was done and "strength" and "conductivity" were evaluated.

Evaluation of hot workability of ingots:

"Hot workability" was evaluated by hot rolling, that is, the ingot was cut into 45 x 45 x 25 mm, heated at 850 ° C for 1 hour, and then subjected to a hot rolling test in three passes from 25 mm to 5 mm in thickness. . The case where a crack was observed visually with respect to the surface and the edge of the sample after hot rolling was made "with a crack", and there was no crack in the surface and an edge, and the smooth case was made into "no crack."

Evaluation of physical properties of the test piece:

About "strength", it carried out using the No. 13 B test piece by the tension test prescribed | regulated to JISZ2241, and measured the tensile strength.

"Electric conductivity" measured the electrical resistance of the test piece using the 4-probe method, and was represented by% IACS.

"Bending workability" was evaluated by the 90 degree W bending test. The test was based on CES-M0002-6, and 90 degree bending process was performed by 50 kN load using the jig | tool of R = 0.1 mm. Evaluation of the bend was made by observing the situation of the central mount surface with an optical microscope, indicating that cracking occurred, × that wrinkles occurred, and △, which was good. The bending axis was set at right angles to the rolling direction.

Evaluation of Ni-P precipitates;

The alloy bath before final cold rolling was cut | disconnected in the rolling direction at right angles in thickness, and the deposit of the cross section was observed by the 10 type visual field using the scanning electron microscope and the transmission electron microscope. 500,000 to 700,000 times field of view (approximately 1.4 × 10 ^{10 to} 2.0 × 10 ¹⁰ nm ² ) for precipitates of 5 to 50 nm, and 50,000 to 100,000 times of field of view (about 1.0 to 100-2000 nm) The imaging was performed at × 10 ^{13 to} 2.0 × 10 ¹³ nm ² ). The long-axis diameter (a), the short diameter (b), and the area of the photographed photograph were individually measured for all the precipitates having a long diameter (a) of 5 nm or more using an image analysis device (manufactured by Nireco Corporation, trade name Ruzex) . 100 randomly selected from these precipitates were obtained, and the average diameter (a ta) and the average diameter (b ta) of the long diameters of all the precipitates were obtained, and the average aspect ratio (a ta / b ta) obtained from these was obtained, respectively. (a), short diameter (b), and aspect ratio (a / b). The sum total of the area of all the precipitates whose major diameter (a) is 5 nm or more was made into the total area of all the precipitates. With respect to the total area of all the precipitates, the ratio of the total area of the precipitates having a long diameter (a) of 10 nm to 50 nm and an aspect ratio (a / b) of 1 to 5 was set as the area ratio (C) (%).

In addition, although the Ni-P type | system | group precipitate which is 20 nm or less in long diameter or the precipitate exceeding 20 nm in diameter by the last cold rolling (usually processing strain ((eta)) = 2 or more), the precipitate which has an aspect ratio exceeding 3 is solid solution 20, It was confirmed that the precipitate having a nm or more and an aspect ratio of 1 to 3 retained its long diameter, short diameter, and aspect ratio even after the final cold rolling. In addition, the area ratio (C) of the precipitates also hardly changed even after the final cold rolling because the precipitates exceeding 200 nm were not dissolved.

The copper alloy of the component composition shown in Table 1 is described with the comparative example about the Example of the high strength highly conductive copper alloy excellent in the hot workability which concerns on this invention. Examples 1-9 of the alloy of this invention did not produce a crack at the time of hot rolling, but had the outstanding strength and electrical conductivity. On the other hand, when the results of Comparative Examples 10 to 22 were examined, Cr was not added or less than the prescribed amount in Comparative Examples 10 to 13, so that cracking occurred by hot rolling. In Comparative Example 14, since the amount of P added exceeded 0.50%, in Comparative Example 15, since the total amount of Sn and In added exceeded 1.0%, in Comparative Example 16, the total amount of added Sn exceeded 1.0%. In each case, cracks occurred during hot rolling. Since the comparative example 17 is Ni addition amount, and the comparative example 18 is low in the addition amount of P in the range which this invention prescribes, it is low in strength. In Comparative Example 19, since the Ni / P ratio is shifted high, the amount of Ni dissolved is increased, the conductivity is lowered, and the strength is also low because the amount of precipitates is small. In Comparative Example 20, since the Ni / P ratio deviated low from the appropriate composition ratio, the amount of P dissolved in solid solution was increased to lower the electrical conductivity. In the comparative example 21, since the addition amount of Ni exceeded 2.0% and the addition amount of P exceeded 0.50%, the crack generate | occur | produced at the time of hot rolling. In Comparative Example 22, since the amount of Cr added was more than 0.45%, compounds such as Ni-P-Cr and Cr-P, or Cr were crystallized or precipitated during solidification, so that the amount of Ni-P-based precipitates was reduced, and the strength and The electrical conductivity is low and bending workability is inferior.

Cu-Ni-P-B Based Alloys

Inventive Examples and Comparative Examples 1-18 (Table 2)

Preparation of Sample (a):

The main raw material is electric copper or oxygen-free copper, with nickel (Ni), 15% P-Cu master alloy (P), 2% B-Cu master alloy (B), tin (Sn), and indium (In) as secondary raw materials. It melt | dissolved in vacuum or argon atmosphere in the high frequency melting furnace, and cast it into the 45 * 45 * 90mm ingot using the casting material made from cast iron. Ingots were subjected to the hot rolling test, and ingots in which cracks did not occur due to hot rolling were performed in the order of hot rolling and solution treatment, aging treatment, intermediate cold rolling, aging treatment, final cold rolling, and strain removal annealing. And a flat plate having a thickness of 0.15 mm. Various test pieces of the obtained board | plate material were extract | collected, and the test was performed and the "strength", the "conductivity", and the "bending workability" were evaluated.

Evaluation of hot workability of ingots (a):

"Hot workability" was evaluated by hot rolling, that is, the ingot was cut into 45 x 45 x 25 mm, heated at 850 ° C for 1 hour, and then subjected to a hot rolling test in three passes from 25 mm to 5 mm in thickness. . The case where a crack was observed visually with respect to the surface and the edge of the sample after hot rolling was "cracked", and there was no crack in the surface and the edge, and the smooth case was set as "no crack."

Evaluation of physical properties of the test piece (a):

About "strength", it carried out using the No. 13 B test piece by the tension test prescribed | regulated to JISZ2241, and measured the tensile strength.

"Electric conductivity" measured the electrical resistance of the test piece using the 4-probe method, and was represented by% IACS.

"Bending workability" was evaluated by the 90 degree W bending test. The test was based on CES-M0002-6, and 90 degree bending was performed by the 50 kN load using the jig | tool of R = 0.1 mm. Evaluation of the bend was made by observing the situation of the central mount surface with an optical microscope, indicating that cracking occurred, × that wrinkles occurred, and △, which was good. The bending axis was set at right angles to the rolling direction.

Evaluation of Ni-P type | system | group precipitate (a);

The alloy bath before final cold rolling was cut | disconnected at right angles in thickness in parallel to the rolling direction, and the precipitate of the cross section was observed in 10 visual fields using the scanning electron microscope and the transmission electron microscope. 500,000 to 700,000 times field of view (approximately 1.4 × 10 ^{10 to} 2.0 × 10 ¹⁰ nm ² ) for precipitates of 5 to 50 nm, and 50,000 to 100,000 times of field of view (about 1.0 to 100-2000 nm) The imaging was performed at × 10 ^{13 to} 2.0 × 10 ¹³ nm ² ). The long-axis diameter (a), the short diameter (b), and the area of the photographed photograph were individually measured for all the precipitates having a long diameter (a) of 5 nm or more using an image analysis device (manufactured by Nireco Corporation, trade name Ruzex) . 100 randomly selected from these precipitates were obtained, and the average diameter (a ta) and the average diameter (b ta) of the long diameters of all the precipitates were obtained, and the average aspect ratio (a ta / b ta) obtained from these was obtained, respectively. (a), short diameter (b), and aspect ratio (a / b). The sum total of the area of all the precipitates whose major diameter (a) is 5 nm or more was made into the total area of all the precipitates. With respect to the total area of all the precipitates, the ratio of the total area of the precipitates having a long diameter (a) of 10 nm to 50 nm and an aspect ratio (a / b) of 1 to 5 was set as the area ratio (C) (%).

In addition, although the Ni-P type | system | group precipitate which is 20 nm or less in long diameter or the precipitate exceeding 20 nm in diameter by the last cold rolling (usually processing strain ((eta)) = 2 or more), the precipitate which has an aspect ratio exceeding 3 is solid solution 20, It was confirmed that the precipitate having a nm or more and an aspect ratio of 1 to 3 retained its long diameter, short diameter, and aspect ratio even after the final cold rolling. In addition, the area ratio (C) of the precipitates also hardly changed even after the final cold rolling because the precipitates exceeding 200 nm were not dissolved.

The Example of the high strength highly conductive copper alloy excellent in the hot workability which concerns on this invention is demonstrated with the comparative example about the copper alloy of the component composition shown in Table 2.

Examples 1-6 of the alloy of this invention did not produce a crack at the time of hot rolling, but had the outstanding strength and electrical conductivity.

On the other hand, about Comparative Examples 7-18, it is an alloy in the component which deviated from the range of the alloy composition of this invention, or Ni / P ratio. In Comparative Examples 7-10, since B was not added or it became less than a prescribed amount, the crack generate | occur | produced by hot rolling. In Comparative Example 11, since the addition amount of Ni exceeds 2.0%, in Comparative Example 12, since the addition amount of P exceeds 0.50%, in Comparative Example 13, since the sum of the addition amounts of Sn and In exceeds 1.0%, the comparison Since the sum total of the addition amount of Sn exceeds 1.0% in Example 14, the crack generate | occur | produced at the time of hot rolling, respectively. In Comparative Example 15, since the Ni / P ratio deviated low from the appropriate composition ratio, the amount of P dissolved in solid solution was increased, resulting in a decrease in electrical conductivity. In Comparative Example 16, since the Ni / P ratio deviated high at an appropriate composition ratio, the amount of Ni dissolved in solution increased, the conductivity decreased, and the strength was also low because the amount of precipitation was small. In Comparative Example 17, since the amount of B added exceeded 0.070%, compounds such as Ni-PB and BP crystallized or precipitated upon solidification, resulting in a decrease in the amount of Ni-P-based precipitates, low strength and electrical conductivity, and bending. Processability is inferior. Comparative Example 18 is low in strength because the addition amount of Ni and P deviates low in the range defined by the present invention.

The external photograph after a hot rolling test is shown to FIGS. 1 is a sample of Inventive Example 3, FIG. 2 is Comparative Example 8, FIG. 3 is Comparative Example 9, and FIG. 4 is a sample of Comparative Example 10.

Inventive Examples and Comparative Examples 19 to 39 (Table 3)

Preparation of Sample (b):

The main raw material is electric copper or oxygen-free copper, with nickel (Ni), 15% P-Cu master alloy (P), 2% B-Cu master alloy (B), tin (Sn), and indium (In) as secondary raw materials. It melt | dissolved in vacuum or argon atmosphere in the high frequency melting furnace, and cast in 45 * 45 * 90mm or (phi) 50 * 90mm ingot. In order to change the cooling rate at the time of casting and solidification, the material of the mold was made of cast iron, alumina, or silica. The thermocouple was inserted into the center of the mold to measure the cooling rate of 1100 to 950 ° C during casting and solidification. As a result, the cast iron mold was 340 ° C / min, the alumina mold was 85 ° C / min, and the silica mold was 33 ° C / min. . Ingots with cooling rates of 20 ° C./min, 15 and 10 ° C./min were obtained in one-way solidification apparatus in order to produce ingots having a cooling rate of 20 ° C./min or less. Ingots were subjected to the hot rolling test, and ingots in which cracks did not occur due to hot rolling were performed in the order of hot rolling and solution treatment, aging treatment, intermediate cold rolling, aging treatment, final cold rolling, and strain removal annealing. And a flat plate having a thickness of 0.10 mm. The various test pieces of the obtained board | plate material were extract | collected, and the test was performed and the "strength", the "conductivity", and the "bending workability" were evaluated.

Evaluation of hot workability of ingots (b):

The ingot was cut into 45 × 45 × 45 mm or φ50 × 45 mm, heated at 850 ° C. for 1 hour, and then hot workability evaluation of the ingot was carried out except that the hot rolling test was performed in four passes from 45 mm to 12 mm in thickness. It carried out similarly to A.

Evaluation of the inclusion of the test piece (b):

Evaluation of inclusions in the sample was carried out in the order of hot rolling and solution treatment, aging treatment, intermediate cold rolling, aging treatment, final cold rolling, strain removal annealing, and mirrored the rolling parallel cross section of the flat sample having a thickness of 0.10 mm. 5 visual field (about 0.35 mm <2>) of the inclusions of 5 micrometers or more were observed by 500 times of the electron microscope SEM image, and the number of inclusions per 1 mm <2> was computed. On the other hand, about the thing which the crack generate | occur | produced in the hot workability evaluation of an ingot, after heating an ingot at 850 degreeC for 1 hour, the inclusion was evaluated with the water-cooled sample. The sample was mirror polished, the inclusions were observed with an electron microscope similarly to the flat plate sample described above, and the number of inclusions per 1 mm 2 was calculated. About the alloy with good hot workability, after heating a flat sample and an ingot at 850 degreeC for 1 hour, the number of inclusions was compared with the water-cooled sample, and almost the same result was obtained.

Evaluation of the physical properties of the test piece (b):

About "strength", it carried out using the No. 13 B test piece by the tension test prescribed | regulated to JISZ2241, and measured the tensile strength. "Conductivity" measured the electrical resistance of the test piece using the double bridge method, and was represented by% IACS. "Bending workability" was evaluated by the 90 degree W bending test. The test was based on CES-M0002-6, and 90 degree bending process was performed by 50 kN load using the jig | tool of R = 0.1 mm. Evaluation of the bend was made by observing the state of the center surface of the central portion with an optical microscope, indicating that cracks occurred, and that wrinkles occurred Δ and good ones ○. The bending axis was set at right angles to the rolling direction.

The copper alloy of the component composition shown in Table 3 of the Example of the high-strength highly conductive copper alloy excellent in the hot workability which concerns on this invention is demonstrated with a comparative example.

Examples 19 to 26 of the alloy of the present invention did not generate cracks during hot rolling, and had excellent strength and electrical conductivity. Since the cooling rate at the time of casting is 20 degreeC / min, this invention example 22 has many inclinations and a little inferior bending workability compared with other invention examples.

On the other hand, about Comparative Examples 27-39, it is an alloy in the component deviating from the range of the alloy composition of this invention, or Ni / P ratio. In Comparative Examples 27-29, since B was not added or it became less than a prescribed amount, the crack generate | occur | produced by hot rolling. In Comparative Example 30, since the addition amount of Ni exceeds 2.0%, in Comparative Example 31, since the addition amount of P exceeds 0.50%, in Comparative Example 32, since the sum of the addition amounts of Sn and In exceeds 1.0%, the comparison Since the sum total of the addition amount of Sn exceeds 1.0% in Example 33, the crack generate | occur | produced at the time of hot rolling, respectively. In Comparative Example 34, since the Ni / P ratio deviated low from the appropriate composition ratio, the amount of P dissolved in solid solution was increased to lower the electrical conductivity. In Comparative Example 35, since the Ni / P ratio deviates high at an appropriate composition ratio, the amount of Ni dissolved is increased, the conductivity is lowered, and the strength is also low because the amount of precipitation is small. In Comparative Example 36, since the amount of B added exceeded 0.070%, compounds such as Ni-PB and BP were crystallized or precipitated upon solidification, so that the amount of Ni-P-based precipitates was reduced, and the strength and conductivity were low. Bendability is poor. In Comparative Examples 37-39, since the cooling rate at the time of casting is slower than a prescribed value in 20 degree-C / min, the crack generate | occur | produced by hot rolling.

In the present invention, by adding a specific amount of Cr or B to the Cu-Ni-P-based alloy, crystallization or precipitation of the Ni-P-based compound to the grain boundary is suppressed, and coarse Ni is preferably controlled by controlling the cooling rate during casting. It suppresses the production of -P-Mg-B and PB compounds. By employ | adopting the said structure, the high temperature brittleness of a grain boundary is improved and hot workability is aimed at.

The copper alloy excellent in the hot workability of this invention shows the outstanding effect for high strength high electric appliances.

Claims (12)

delete delete delete delete Ni: 1.0% to 2.0%, P: 0.1% to 0.5% by mass ratio, the content ratio of Ni and P is Ni / P: 4.0 to 6.5, B: 0.005% to 0.070%, and the balance is Consisting of Cu and unavoidable impurities, The copper alloy excellent in hot workability whose number of inclusions with a long diameter of 5-50 micrometers is 100 or less per 1mm <2>, and whose number of inclusions exceeding 50 micrometers in long diameter is 0 per 1mm <2>. In the mass ratio, Ni: 1.0% to 2.0%, P: 0.1% to 0.5%, the content ratio of Ni and P is Ni / P: 4.0 to 6.5, and B: 0.005% to 0.070%. At least one of Sn and In is contained in a total of 0.01% or more and 1.0% or less, the balance consists of Cu and unavoidable impurities, The copper alloy excellent in hot workability whose number of inclusions with a long diameter of 5-50 micrometers is 100 or less per 1mm <2>, and whose number of inclusions exceeding 50 micrometers in long diameter is 0 per 1mm <2>. delete The method according to claim 5 or 6, A copper alloy excellent in hot workability for high strength high-conductivity electronic devices having a tensile strength of 700 MPa or more and 950 MPa or less and a conductivity of 40% IACs or more and 65% IACs or less. delete delete The manufacturing method of the copper alloy excellent in hot workability of Claim 5 or 6 whose average cooling rate of 1100 degreeC-950 degreeC at the time of casting is 20 degreeC / min or more and 1500 degrees C / min or less. The manufacturing method of the copper alloy excellent in hot workability of Claim 5 or 6 whose average cooling rate of 1100 degreeC-950 degreeC at the time of casting is 30 degreeC / min or more and 1500 degrees C / min or less.

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