JPH0148343B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has developed a steel plate for electronic parts that prevents the occurrence of "blister", which is one of the internal defects in cold-rolled thin steel strips.
The present invention provides a Ni-Fe alloy. High Ni-Fe alloys are essential as materials for electronic components.For example, 36%Ni, which has the lowest coefficient of thermal expansion, is used as a material for shadow masks for color television receivers.
-Fe alloy is used for IC lead frame materials, while 42% Ni-Fe alloy and 51% Ni-Fe alloy, which have excellent sealing properties with the package and good plating and solderability, are also used for IC lead frame materials. 42% Ni-6 is used for lead frame materials for fluorescent display tubes that require strong sealing.
%Cr-Fe alloy is used. These shadow masks and lead frames are made of cold-rolled thin plate coils with a thickness of 0.25 to 0.15 mm, and are processed into predetermined mask and frame shapes by photo-etching and punching processes. Since these are precision parts, the requirements for processing accuracy and quality accuracy are extremely strict, and the characteristics required of the material include thickness accuracy, flatness, coarse inclusions, two-piece cracking, ``blister'', etc. Strict regulations are in place for internal defects. However, internal defects called "blisters", which extend in the rolling direction and are about 1 mm wide and 15 mm long, often occur in the cold-rolled thin sheet coils made of the high Ni-Fe alloy. The thinner the thickness, the more noticeable it becomes. Such "blisters" significantly impede the shape of the shadow mask and lead frame, that is, the processing accuracy, and impair quality, so the occurrence of "blisters" in cold-rolled coils can be a fatal defect as a material for electronic components. As a result of intensive research to prevent "blisters" that occur in high-Ni-Fe alloy cold-rolled thin steel strips, the present inventors found that N
We found that "blister" can be completely prevented by strictly limiting the content to 0.002% or less.
The invention has been completed. In high Ni-Fe alloys, N is significantly activated, and even a very small amount of N, for example, below the bombardment solubility determined as an equilibrium state, will cause minute bubbles in the cast iron due to the concentration phenomenon during solidification. . Such minute N ₂ bubbles generated in the ingot do not impede the workability of this alloy, such as hot workability, in normal applications, and are easily detected by non-destructive testing. It is impossible. However, when the plate is rolled to a thickness of about 0.2 mm, which is required for electronic component materials, hot rolling during annealing...
Some N ₂ that did not completely disappear during cold rolling
If the bubble expands and the internal pressure at this time overcomes the restraining force due to the plate thickness, it is estimated that "blister" will occur. That is, in the present invention, Ni: 35 to 55%, Mn:
1.2% or less, Si: 0.3% or less, or Ni: 35 to 55
%, Cr: 3-10%, Mn: 1.2% or less, Si: 0.3%
In the following, by limiting the amount of N to 0.002% or less in an alloy in which the balance consists of Fe and unavoidable impurities, we will discuss how to cool a high Ni-Fe alloy that can produce sound electronic parts without internal defects "blisters". The present invention provides an alloy for rolled ribbon. The reasons for limiting the components in the present invention are as follows. Ni: As a material for electronic components, it is the most important element that controls thermal expansion, 36% at room temperature.
The coefficient of thermal expansion is the lowest at 42% in the 300°C range and 52% in the 500°C range. Therefore, 35 to 55% is required to obtain low thermal expansion. Cr: This is an element that affects the sealing property with glass, which is a necessary property as a material for electronic parts.If it is less than 3%, the sealing property is poor, and if it exceeds 10%, the low thermal expansion property is impaired. Therefore, 3-10% is required. N: This is an element that causes blisters, and the amount thereof is preferably as small as possible. In order to prevent blistering in cold-rolled steel strips with a thickness of around 0.2 mm, which are required as materials for electronic parts, the content must be 0.002% or less. Mn: Indispensable as a deoxidizing element, and also effective in hot workability. However, if it exceeds 1.2%, the coefficient of thermal expansion will increase significantly, so it should be kept at 1.2% or less. Si: An essential element as a deoxidizing agent, but 0.3%
If the above content is included, the coefficient of thermal expansion will increase significantly and the hot workability will also deteriorate, so it should be set to 0.3 or less. By satisfying the above conditions, the present invention makes it possible to obtain a cold-rolled thin steel strip for electronic components that is free from internal defects and has good quality. A detailed explanation will be given below based on a specific example. Table 1 shows the chemical composition, plate thickness, and presence or absence of blistering of the high Ni-Fe alloy cold-rolled steel strips tested.

【table】

[Table] These materials were roughly manufactured using the following steps. In both cases, a 6.5 ton cast soul produced by 40 ton electric furnace → converter → vacuum degassing → casting is divided into pieces → hot rolling → cold rolling → annealing → finish rolling, and the final plate thickness is 0.18 to 0.25 mm and the hardness is is adjusted to Hv = around 200. To check for the occurrence of blisters in these steel strips, the coils were passed through an inspection line and both surfaces of the coils were visually inspected, and if even one blister was found within the coils, it was determined that there were blisters. In Table 1, coils No. 1, 2, 9, and 10 are made of 36% Ni.
-Fe alloy, coil No. 3, 4, 11, 12 is 42% Ni-
Fe alloy, coil No. 5, 6, 13, 14 is 51% Ni-Fe
Alloy, coil No.7, 8, 15, 16 is 42%Ni-6%
The figure shows the case of a Cr-Fe alloy, but the occurrence of blisters in any alloy system is controlled by the N content, and the occurrence of blisters can be prevented by keeping the N content below 0.002%. do not have. As explained above, the present invention makes it possible to provide a high-quality material for electronic components that is extremely effective in preventing blisters that occur in high Ni-Fe alloy thin steel strips and has no internal defects, and has great industrial value. be.

Claims (1)

[Claims] 1 Ni: 35 to 55% Mn: 1.2% or less Si: 0.3% or less High Ni- consisting of balance Fe and unavoidable impurities
In Fe alloy: An alloy for electronic parts characterized by having a N content of 0.002% or less. 2 Ni: 35-55% Cr: 3-10% Mn: 1.2% or less Si: 0.3% or less High-Ni content with the balance consisting of Fe and unavoidable impurities
-In the Fe alloy: An alloy for electronic parts, characterized in that the amount of N is 0.002% or less.