JPH02101116A - Production of fe-ni alloy having significant streaking inhibiting effect at the time of etching - Google Patents

Abstract

PURPOSE:To produce an Fe-Ni alloy not causing streaking at the time of etching by successively subjecting an Fe-Ni alloy contg. specified amts. of Ni and B to heating, upsetting and hot forging under specified conditions. CONSTITUTION:An Fe-Ni alloy ingot contg. 30-80wt.% Ni and 0.001-0.03wt.% B is heated to >=900 deg.C, upset in 1/>=1.2U upsetting ratio and hot forged at >=30% total reduction of area. By this forging, the grains are homogenized and segregation is reduced to inhibit streaking at the time of etching. Superior etchability can be ensured and the resulting alloy has desired properties as an electronic or electromagnetic material.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides F
The present invention relates to a method for producing an e-Ni alloy, and in particular to an Fe-Ni alloy that is suitably used as a material for electronic devices such as shadow masks for color TV cathode ray tubes and fluorescent display tubes.

The Fe-Ni alloy of the present invention is 36Ni amber alloy for shadow masks and 42Ni amber alloy for lead frames.
Targets include Ni alloys, Fe-Ni alloys for electronic and electromagnetic applications that are used with a focus on low thermal expansion and magnetic properties, and permalloy alloys that are used as electromagnetic materials.

[Conventional technology]

Iron-Nisokel alloy @ (Fe-Ni alloy) for use as a material for shadow masks for color TV cathode ray tubes has the drawback of producing white streaks or "uneven streaks" when producing shadow masks by photo-etching holes. One thing was pointed out.

In the past, several techniques have been proposed to suppress the occurrence of uneven streaks during etching.
The technology disclosed in Publication No. 0-128253 reduces the segregation of nickel components by heating an ordinary ingot to 850°C or higher and then forging it with a total area reduction rate of 40% or more in each heat. This suppresses the occurrence of uneven streaks.

In addition, the technology disclosed in JP-A No. 61-223188 manages the segregation rate and segregation band of nickel by preventing segregation during ingot production or performing nickel diffusion treatment by heat treatment during the strip manufacturing process. This suppresses uneven etching lines.

[Problem to be solved by the invention]

However, the above-mentioned conventional technology disclosed in JP-A No. 60-128253 is characterized by forging such that the total area reduction rate exceeds 40%, but this level of work is generally performed. However, such a method does not easily eliminate the segregation of various elements, and is therefore insufficient to prevent the occurrence of uneven streaks during etching.

On the other hand, the above-mentioned conventional technology disclosed in JP-A No. 61-223188 is characterized by reducing component segregation through diffusion of Ni through high-temperature heat treatment, but the plate thickness is thin compared to heating at the slab stage. Therefore, there was a problem in that the oxidation loss became relatively large, resulting in a significant decrease in yield.

In shadow masks for various displays that require particularly high precision, the holes to be drilled have a diameter of about 172 and more than twice the number of holes in consumer TV shadow masks, and the quality of the material is directly affected by etching. It is difficult to completely avoid the occurrence of streak unevenness because it affects the uniformity of the holes during etching, and therefore, the reality is that it is not possible to completely suppress the streak unevenness during etching.

In view of the actual situation in the industry, the object of the present invention is to create an alloy material that does not cause uneven streaks during etching, that is, contains 30 to 80% Ni and 0.001 to 0.0% B.
The present invention proposes a method for advantageously producing a Fe-Ni alloy containing 3% Fe--Ni.

[Means to solve the problem]

Therefore, the present inventors aimed to realize the above-mentioned purpose (JFe
- Various studies were conducted on streak unevenness in Ni-based alloys. As a result, we found that the causes of uneven streaks include ■C, Si,
It was found that the main factors were component segregation of impurity elements such as Mn and Cr, and (1) differences in crystal structure.

For example, in areas where impurity elements such as C, St, Mn, and Cr are segregated, the etching/notching speed is different compared to other areas, resulting in differences in hole shape during photoetching and uneven streaks. It is the cause.

On the other hand, regarding the difference in crystal structure, for example, (100
) In areas where many planes are oriented, compared to other areas,
The etching speed increases, resulting in differences in hole shape during photoetching. This is due to the presence of a solidified structure during casting, that is, a columnar structure with a specific orientation, and this columnar structure does not disappear even in the subsequent processing and heat treatment stages, and is elongated in the rolling direction while changing its shape. ,
This ultimately causes uneven streaks.

Furthermore, according to the findings of the present inventors, Fe-N
It has been found that the use of B as an additive component in the i-based alloy has the effect of disrupting the columnar crystals during slab heating and accelerating randomization.

Therefore, in the present invention, an attempt was made to overcome the above-mentioned problems by aiming not only at suppressing component segregation but also at adjusting the crystal structure through the synergistic effect of the addition of B.

That is, as a means to overcome this problem, the present invention provides Ni in an amount of 30 to 80 wt% and B in an amount of 0.002 to 0.03 wt%.
After heating an ingot of an Fe-Ni alloy containing t% and the remainder being mainly Fe to a temperature of 900 ° C. or higher,
An Fe-Ni alloy that has an excellent effect of suppressing streak unevenness during etching, which is characterized by performing sewage forging with a forging forming ratio of 1/1.2U or more, and then hot forging with a total cross-section reduction rate of 30% or more. We propose a manufacturing method for

[For production]

Now, in the present invention, the lower limit of the Ni content of the material is set to 3h+t% (hereinafter simply abbreviated as "%") because this Ni-containing This is because if the Ni content is less than 30%, sufficient electromagnetic properties will not be exhibited and it will not be practical.
This is because if it exceeds 0%, the quality as an electronic or electromagnetic material will deteriorate.

As the material to be perforated by photoetching, it is more preferable to use a Fe--Ni alloy containing 50% or less Ni.

In addition, B is an important element that emphasizes the characteristics of the Fe-Ni alloy of the present invention, and it prevents impurity elements such as C, Si, Mn, and Cr from segregating at the grain boundaries, and also acts as a self-adhesive element at the grain boundaries. It preferentially agglomerates in other defects and becomes nuclei for recrystallization, making crystal grains finer and promoting equiaxed crystallization. However, such an effect is insufficient at a content of less than 0.0OI%, and as the content increases, it shows a remarkable effect, but when added in an amount exceeding 0.03%, M
In addition to intermetallic compounds of 2B (Ni, Cr, Fe),
The upper limit needs to be limited to 0.03% because various borides containing C, O, and N are generated, increasing the risk of solidification cracking at high temperatures.

Next, the heating temperature of the ingot prior to forging was set to 900°C.
The reason for this is that if the heating temperature is less than 900°C, forgeability deteriorates and component segregation cannot be reduced. It goes without saying that the upper limit of the heating temperature should not exceed the melting point.

In addition, the reason why the forging forming ratio in the suede forging (hereinafter referred to as the suede forging ratio) was set to 1/1.2 U or more is that if the suede forging ratio is less than 1/1.2 U, the crystals cannot be made sufficiently uniform. This is because uneven streaks occur. This will be explained in more detail below.

In other words, such uneven streaks are caused by giant crystal grains with a specific orientation during casting that are elongated in the rolling direction during rolling while changing their shape without disappearing during subsequent processing and heat treatment. It turned out that. Moreover, according to the research of the present inventors, when crystal grains with a specific orientation are short when processed to the final plate thickness, their width and length are also relatively small (and the etching perforation becomes difficult). The differences in local etching rates that sometimes occur are not observed, and therefore,
Continuous uneven streaks were not observed. However, when these columnar crystals (crystal grains) have a long length, even after processing, the width and length of the columnar crystals (crystal grains) remain as they are, that is, they remain large, and this causes uneven streaks during etching. .

The length of the crystal grains, which is the limit for whether or not this streak unevenness will appear, is determined by the forging process.In other words, if the forging ratio is less than 1/1.2U, the length of the crystal grains becomes longer. This results in the occurrence of uneven streaks.

Next, the reason why we set the total cross-section reduction rate in the forging that follows the above-mentioned suede forging (including physical training and extension training) to 30% or more is because if it is less than 30%, the reduction of component segregation due to forging is sufficiently achieved. This is so that it will not happen.

As described above, by forging the Fe-Ni alloy ingot added with B under specific forging conditions, it is possible to homogenize the crystal grains and reduce component segregation, thereby suppressing uneven streaks during etching. It is possible to ensure extremely excellent etching properties.

〔Example〕

Table 1 shows the chemical composition of the Fe--Ni alloy used in this example, the conditions of implementation, and the evaluation results of the obtained product.

The alloys shown in Table 1, which are particularly targeted by the present invention, are obtained by refining molten metal in an electric furnace by the AOD method or VOD method, and then forming ingots as shown in Table 1. After hot forging according to the conditions to form a slab, hot rolling was performed to form a coil with a thickness of 5.51 mm.

After the hot rolling, a final product was obtained by performing treatments according to a conventional method by appropriately combining cold rolling and heat treatment.

The test material produced in this way was mixed with a ferrous chloride solution (
Actual photoetching was performed at a temperature of 1.45.50°C (specific gravity: 1.45.50°C), and the presence or absence of uneven streaks was investigated.

The results were as shown in Table 1.

As can be seen from Table 1, the Fe-Ni alloy manufactured according to the method of the present invention has a higher etching rate than the Fe-Ni alloy (comparative example) manufactured according to the conventional method with the same composition. Almost no streaks were observed, making it clear that the alloy is an excellent material for etching.

〔Effect of the invention〕

As explained above, the Fe-Ni alloy to which an appropriate amount of B is added, which is produced by the method of the present invention, has no uneven streaks after photo-etching, and therefore is highly resistant to electrons.

A Fe-Ni alloy having properties desirable as an electromagnetic material can be provided at low cost.

Patent applicant Nippon Yakin Kogyo Co., Ltd. Agent Patent Attorney Jun Tama Kogawa Quantity Patent attorney Morio Nakamura

Claims (1)

[Claims] 1. 30 to 80 wt% Ni and 0.001 to 0 B
．． Fe-N containing 03 wt% and the remainder being mainly Fe
The ingot of the i-series alloy is heated to a temperature of 900°C or higher, then subjected to sewage forging at a forging forming ratio of 1/1.2U or higher, and then hot forged at a total cross-section reduction rate of 30% or higher. A method for producing a Fe-Ni alloy that has an excellent effect of suppressing streak unevenness during etching.