JPH07179998A - Cold rolled sheet of fe-ni alloy excellent in plating suitability and punchability - Google Patents

Abstract

PURPOSE:To stably produce a cold rolled sheet of Fe-Ni alloy excellent in plating suitability and punchability. CONSTITUTION:This cold rolled sheet has a composition consisting of, by weight, 30-45% Ni, 0.2-0.8% Mn, 0.003-0.030% Al, 0.0008-0.005% S, and the balance Fe with inevitable impurities. These inevitable impurities are constituted of, by weight, <=0.25% Si, <=0.1% Cr, <=0.010% C, <=0.006% N, <=0.005% P, <=0.005% O, and non-metallic inclusions containing <=5% CaO and, as the balance component, one kind among Al2O3, MgO, and Al2O3-MgO. Moreover, as to the form of the non-metallic inclusions in the cold rolled sheet, the diameter of the inclusions is regulated to <=10mum by average diameter, and further, the distribution of the inclusions of 6-10mum average diameter is controlled to <=100 pieces for 100mm and also the distribution of the inclusions of <=6mum average diameter is controlled to >=10pieces for 100mm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a proposal for an Fe-Ni alloy cold-rolled sheet which is suitable for use as a lead frame material and which has excellent plating properties and punching properties.

[0002]

2. Description of the Related Art Generally, an Fe-Ni alloy is an extremely thin cold-rolled sheet having a thickness of about 0.25 mm, and the cold-rolled sheet is processed into a predetermined frame shape or a mask shape to obtain a lead frame or a shadow. It is used as a material for electronic parts such as masks. In particular, with respect to the lead frame material, the requirements for processing accuracy and quality are becoming more and more stringent with the recent development of the electronic industry.

On the other hand, conventionally, the above requirements can be satisfied.
As such a Fe-Ni alloy cold-rolled sheet, JP-A-62-161936
In the publication, the composition of non-metallic inclusions in the Fe-Ni alloy cold rolled sheet is
Al₂O ₃-MgO-SiO₂Fe- with excellent surface properties controlled by the system
Ni-based alloy cold-rolled sheet has been proposed. In addition, JP-A-4-21
In the 8644 publication, the composition of non-metallic inclusions is defined as CaO-Al.₂O₃-MgO
System, its melting point is 1600 ° C or higher, and its particle size is 6 μm or less
Fe-Ni with excellent cleanliness and etching perforation
System alloy cold rolled sheets have been proposed.

[0004]

By the way, the lead frame material using the Fe--Ni alloy has excellent punching property, that is, the die for punching is less worn and the punching surface is not disturbed. It's important. If there are many non-metallic inclusions on the surface of the material, the punching surface will be disturbed due to the hardness difference between the non-metallic inclusions and the matrix. Therefore, there is a strong demand for lead frame materials that are highly clean and have no non-metallic inclusions.

However, in the case of the Fe-Ni alloy cold-rolled sheet described in the above-mentioned JP-A-62-161936, it exhibits ductility even at the hot working temperature because of the low melting point of non-metallic inclusions. Exists in the hot rolling direction. This means an increase in the area of inclusions on the punching surface, which deteriorates the cleanliness at the product stage. Therefore, when cold-rolled material containing such non-metallic inclusions is punched, the punching surface is disturbed, the boundary between the cut surface and the fracture surface of the material becomes unclear, and wear of the punching die becomes severe. There was a problem.

Further, it is important that the lead frame material using the Fe--Ni alloy has excellent plating properties, that is, blistering defects do not occur due to heating after plating.
For that purpose, it is necessary for the lead frame material to form a uniform plated surface by an activation treatment or the like performed before plating.

However, in the case of the Fe-Ni alloy cold-rolled sheet described in Japanese Patent Laid-Open No. 4-218644, since CaO is contained as a non-metallic inclusion in the sheet, a degreasing step in a pretreatment for plating using an aqueous solution. At times, the CaO component is preferentially eluted. Therefore, in the cold-rolled material containing such inclusions, the surface condition is always disturbed and non-uniform. When plating is performed on such a material, there is a problem that blistering defects occur due to heating after plating.

An object of the present invention is to eliminate the problems of the above-mentioned respective prior arts. That is, the present invention maintains the basic characteristics of the Fe-Ni-based alloy cold-rolled sheet for lead frames, and is also excellent in plating and punching properties.
-To stably provide a cold rolled Ni alloy sheet.

[0009]

As a result of intensive studies to achieve the above object, the inventors have come up with an invention having the following contents as its gist. That is, the present invention is Ni: 30 to 45 wt%, Mn: 0.2 to 0.8 wt%, Al: 0.003 to 0.030 wt%, S: 0.0008 to 0.005 wt%, the balance being Fe and inevitable impurities, and the inevitable Impurities are Si ≤ 0.25wt%, Cr ≤ 0.1wt%, C ≤ 0.010wt%, N ≤ 0.006wt%, P ≤ 0.005wt%, O ≤ 0.005wt% and non-metallic inclusions: CaO ≤ 5wt% Al as the balance component
₂ O ₃ , MgO or one containing Al ₂ O ₃ -MgO, and the morphology of the non-metallic inclusions in the cold-rolled sheet is 10 μm or less in average diameter as inclusions. And the distribution of inclusions with an average diameter of 6 to 10 μm per 100 mm ²
Distribution of inclusions less than 100 and average diameter less than 6 μm
It is a Fe-Ni alloy cold-rolled sheet excellent in plating property and punching property, which is controlled to 10 or more per 100 mm ² . Here, the average diameter of the inclusions means the equivalent circle equivalent diameter of the non-metallic inclusions.

[0010]

In the following, the reason why the alloy composition of the present invention is limited to the above range will be explained. Ni: 30 to 45 wt% Ni is an element that greatly affects the coefficient of thermal expansion of the Fe-Ni alloy. If the coefficient of thermal expansion of the Fe-Ni alloy increases,
The difference in the coefficient of thermal expansion from the Si chip becomes large, and it cannot be used for lead frames. Therefore, in order to maintain the basic characteristics of the cold rolled sheet for lead frames, Fe
-The coefficient of thermal expansion of the Ni-based alloy must be set to a value similar to that of Si. Therefore, the Ni content is limited to the range of 30 to 45 wt% so as to show a value similar to that of Si.

Mn: 0.2-0.8 wt% Mn is an element having an action of improving the hot workability of the Fe-Ni alloy. However, the Mn content is 0.2 wt%
If the amount is less than that, the effect is small and improvement in hot workability cannot be expected. On the other hand, when the content of Mn is more than 0.8 wt%, the hardness of the alloy plate becomes excessively high and it becomes unsuitable as a lead frame material. Therefore, the Mn content is limited to the range of 0.2 to 0.8 wt%.

Al: 0.003 to 0.030 wt% Al is the amount and particle size of non-metallic inclusions in the Fe-Ni alloy.
Furthermore, it is an element that affects the regulation of the amount of oxygen in the Fe-Ni alloy. However, the content of Al is 0.003
If it is less than wt%, the amount of oxygen in the alloy becomes too large, while if it exceeds 0.030 wt%, inclusions become coarse, so the range was limited to 0.003 to 0.030 wt%.

S: 0.0008 to 0.005 wt% S is generally considered to be one of the unavoidable impurities in Fe-Ni alloys, such as deterioration of hot workability and corrosion resistance. It is said that the smaller the S content, the more preferable. However, according to the research results of the present inventors, in addition to this S, if it is too small, that is, if it is less than 0.0008 wt%, the punching property, which is one of the important properties as a lead frame cold rolled material, deteriorates. I found out that On the other hand, 0.005wt%
If it exceeds the above range, the hot workability of the Fe-Ni alloy will be deteriorated. As described above, in the present invention, S is an element that plays an extremely important role, and its content is 0.00
It must be limited to the range of 08 to 0.005wt%.

Si ≦ 0.25 wt% Si is one of the impurities inevitably mixed in the Fe-Ni alloy, and the smaller the content, the better. However, it is economically difficult to significantly reduce the Si content on an industrial scale, while if the Si content exceeds 0.25 wt%, a large amount of silica inclusions are generated in the alloy. Fe-
0.25wt because it impedes the punching property of the Ni alloy cold rolled sheet.
It is necessary to limit it to% or less.

Cr ≦ 0.1 wt% Cr is one of the impurities unavoidably mixed in the Fe—Ni alloy, and the smaller the content, the better. However, it is economically difficult to significantly reduce the Cr content on an industrial scale, while when the Cr content exceeds 0.1 wt%, a large amount of chromium oxide is generated in the alloy. Fe-
0.1wt% because it impedes the punching property of Ni-based alloy cold-rolled sheet.
It is necessary to limit it to% or less.

C ≦ 0.010 wt% C is one of the impurities inevitably mixed in the Fe—Ni alloy, and the smaller the content, the better. However, it is economically difficult to significantly reduce the C content on an industrial scale, while the C content is 0.010 wt%.
If it exceeds the limit, a large amount of iron carbide is generated in the alloy and Fe-Ni
0.010wt because it impedes the punching properties of cold rolled alloys
It is necessary to limit it to% or less.

N ≦ 0.006 wt% N is one of the impurities inevitably mixed in the Fe—Ni alloy, and the smaller the content, the better. However, it is economically difficult to significantly reduce the N content on an industrial scale, while the N content is 0.006 wt%.
Beyond the Fe content, a large amount of metal nitride is formed in the alloy and Fe-
0.006wt% as it impairs the plating property of Ni alloy cold rolled sheet.
Must be limited to:

P ≦ 0.005 wt% P is one of the impurities that are inevitably mixed in the Fe—Ni alloy, and the smaller the content, the better. However, it is economically difficult to significantly reduce the P content on an industrial scale, while the P content is 0.005 wt%.
If it exceeds 1.0%, the hot workability deteriorates, so it is necessary to limit it to 0.005 wt% or less.

O ≦ 0.005 wt% O is one of the impurities inevitably mixed in the Fe—Ni alloy, and the smaller the content, the better. However, it is economically difficult to greatly reduce the O content on an industrial scale, while the O content is 0.005 wt%.
If more than 0.005% by weight, oxides are formed in the alloy in a large amount to impede the punching property of the Fe-Ni alloy cold-rolled sheet.
Must be limited to:

Non-metallic inclusions: CaO ≤ 5 wt% and containing any one of Al ₂ O ₃ , MgO or Al ₂ O ₃ -MgO as the balance component Non-metallic inclusions are Fe-Ni based alloys. It is one of the impurities inevitably mixed in, mainly CaO, MgO and Al ₂ O ₃
Is the basic ingredient. In particular, CaO is an element that has a great influence on the plating properties of Fe-Ni alloy cold-rolled sheets, and if its content exceeds 5 wt%, CaO is used in the degreasing step of the plating pretreatment.
Elutes, the surface of the material becomes non-uniform, and blistering defects occur due to heating after plating. Therefore, the CaO content is 5 wt.
% Or less.

Further, in the present invention, in addition to the control focusing on the composition of the nonmetallic inclusion components as described above, the form of the nonmetallic inclusions contained in the alloy, that is, the size of the inclusions (average It is characterized in that it also controls the diameter and its distribution. This is because the form of the non-metallic inclusions, that is, the average diameter of the inclusions and the distribution of the inclusions have a great influence on the punchability of the Fe—Ni alloy cold-rolled sheet.

A specific form control method will be described below. When the average diameter of inclusions is more than 10 μm in the cold rolled material, the distribution of inclusions with an average diameter of 6 to 10 μm is 100 per 100 mm ^2.
When the number of inclusions is more than 10 or the distribution of inclusions with an average diameter of less than 6 μm is less than 10 per 100 mm ² , the Fe—Ni alloy cold-rolled sheet has a significantly deteriorated punching property, resulting in poor punching. The properties of non-metallic inclusions contained in the alloy are specified so that
It is necessary to control the average diameter of inclusions and their number distribution.
That is, the average diameter of inclusions is 10 μm or less, the distribution of inclusions having an average diameter of 6 to 10 μm is 100 or less per 100 mm ² , and the distribution of inclusions having an average diameter of less than 6 μm is 10 or more per 100 mm ^2. .

As explained above, the Fe-Ni alloy cold-rolled sheet of the present invention is characterized in that the composition of the non-metallic inclusions and the morphology of the inclusions are controlled. The component composition of the metal inclusions affects the lead frame material during or after the chemical treatment, while the morphology of the non-metal inclusions affects the punchability of the cold rolled sheet. .

In the present invention, as the quantitative evaluation of nonmetallic inclusions, the form of inclusions, that is, the average diameter and the number distribution of inclusions are used without using the conventionally used cleanliness. This is because the evaluation based on the cleanliness is unstable and ambiguous in the case of a metal material having relatively high cleanliness as in the present invention.

[0025]

EXAMPLE A test was conducted in order to confirm the action and effect of the present invention. The result will be described below. 20 kg in a chamber adjusted to an inert gas (argon) atmosphere
Using a high-frequency induction furnace equipped with a crucible of high capacity (made of Al ₂ O _3, made of CaO, made of MgO), electrolytic iron and electrolytic Ni were housed and melted in the crucible, and further metallic Al was charged. While performing deoxidation, ferromanganese, iron sulfide, etc. are added to adjust the composition to obtain the composition shown in Table 1, and the alloy melt obtained in this manner is cast into an ingot shape, followed by hot working. After being forged into a plate having a thickness of 6 mm, a cold-rolled plate sample was prepared by cold rolling. In addition, No. 1 to 8 and 12 to 14 are MgO
Samples melted in a crucible, No. 9 and 10 are CaO
A sample dissolved in manufacturing crucibles, No.11 is, Al ₂ O ₃
It is a sample dissolved in a crucible. In this test dissolution, the average diameter of the inclusions and the number distribution thereof were controlled by introducing slag of the specified component.
That is, the slag components for sample Nos. 1 to 8 and 12 to 14 are
Al ₂ O ₃ -MgO was used, the slag component for sample Nos. 9 and 10 was Al ₂ O ₃ -CaO-MgO, and the slag component for sample No. 11 was Al ₂ O ₃ -SiO ₂ . . Then, after a predetermined stirring operation for controlling the amount of inclusions by the slag, it was allowed to stand and then poured into a mold to obtain a test sample.

The punching properties and plating properties of the cold-rolled sheet samples thus obtained were evaluated. The results are also shown in Table 1. In the table, Nos. 1 to 6 are Fe-Ni alloy cold-rolled sheets of the present invention, Nos. 7 and 8 are cold-rolled sheets in which S is outside the applicable range, and Nos. 9 and 10 are non-metallic. CaO in inclusions is a cold-rolled sheet outside the applicable range, No. 11 is a cold-rolled sheet in which the components of non-metallic inclusions are different from those of the present invention, and Nos. 12 to 14 are properties of non-metallic inclusions. Is a cold rolled sheet outside the applicable range.

As is clear from the results shown in this table, all the Fe-Ni alloy cold-rolled sheets of the present invention were excellent in punching property and plating property. On the other hand, all of the comparative materials of Nos. 7 to 14 caused punching failure or plating failure and were significantly inferior in punching property or plating property.

The method of evaluating punching property and plating property will be described below. (1) Evaluation of punching property Each sample material was rolled to a thickness of 0.15 mm and then punched into a size of 2 × 20 mm using a metal. The state of wear of the die and the cross-sectional state of the punched material after punching 300 sheets were observed by a microscope and evaluated. In the evaluation, as shown in FIG. 1, when the boundary between the cut surface and the fracture surface of the punched material can be clearly observed and the ratio is constant, the normal punched cross section is shown, and it is indicated as ◯ in Table 1. In this case, the wear of the mold was good. On the other hand, as shown in FIG. 2, when the boundary between the cut surface and the fracture surface of the punched material was unclear and the ratio was not constant, it was determined as a defective punched cross section, and is shown as X in Table 1. In this case, wear of the mold was severe. (2) Evaluation of plating property Each sample material was rolled to a thickness of 0.15 mm, and then degreased by washing with CPE-1000 (manufactured by Mitsubishi Gas Chemical Co., Inc.).
Then, after performing Ag plating by electrodeposition, heating was performed at 500 ° C. for 1 hour, and after air cooling, the surface was observed and evaluated. In the evaluation, when a protrusion having a diameter of about 2 mm was generated on the surface, it was determined to be defective, and is shown in Table 1 as x.

[0029]

[Table 1]

[0030]

As described above, according to the present invention, particularly while maintaining the basic characteristics of the cold-rolled sheet for lead frames, it is extremely useful as a material for electronic parts which is excellent particularly in plating property and punching property. A Fe-Ni alloy cold rolled sheet can be stably provided.

[Brief description of drawings]

FIG. 1 is a view showing a normal punching section in evaluation of punching property.

FIG. 2 is a diagram showing a defective punching section in the evaluation of punching property.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiyuki Shimizu 4-2 Kojima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Metallurgical Industry Co., Ltd. Technical Research Center

Claims (1)

[Claims] 1. Ni: 30 to 45 wt%, Mn: 0.2 to 0.8 wt%, Al: 0.003 to 0.030 wt%, S: 0.0008 to 0.005 wt%, the balance being Fe and inevitable impurities, and the inevitable impurities. , Si ≤ 0.25 wt%, Cr ≤ 0.1 wt%, C ≤ 0.010 wt%, N ≤ 0.006 wt%, P ≤ 0.005 wt%, O ≤ 0.005 wt% and non-metallic inclusions: CaO ≤ 5 wt% Al as an ingredient
₂ O ₃ , MgO or one containing Al ₂ O ₃ -MgO, and the morphology of the non-metallic inclusions in the cold-rolled sheet is such that the inclusion diameter is 10 μm or less in average diameter. The distribution of inclusions having an average diameter of 6 to 10 μm is 100 or less per 100 mm ² , and the distribution of inclusions having an average diameter of less than 6 μm is 10 per 100 mm ^2.
A Fe-Ni alloy cold-rolled sheet having excellent plating properties and punching properties, characterized in that the cold-rolled Fe-Ni alloys are controlled to be more than one.