JPH0711032B2 - Method for producing Fe-Ni based alloy excellent in streak unevenness suppressing effect during etching - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides Fe, which has an excellent effect of suppressing streak unevenness during etching.
The present invention relates to a method for producing a Ni-based alloy, and more particularly to a Fe-Ni-based alloy that is preferably used as a material for electronic devices such as shadow masks for color television Braun tubes and fluorescent display tubes.

Incidentally, the Fe-Ni-based alloy of the present invention, 36Ni amber alloy for shadow mask, 42Ni alloy for lead frame, electronic used for the low thermal expansion characteristics and magnetic characteristics, Fe-Ni-based alloy for electromagnetic, It also targets permalloy alloys used as electromagnetic materials.

[Conventional technology]

Iron-nickel alloy steel (Fe-Ni alloy) for shadow mask material of color TV cathode-ray tubes has a drawback that white streak pattern or "streak unevenness" occurs when manufacturing a shadow mask by photo-etching perforation of this steel. It was pointed out that there is.

Heretofore, several techniques have been proposed for suppressing the occurrence of streak unevenness during etching.
According to the technology disclosed in Japanese Unexamined Patent Publication No. 128253, after heating an ordinary ingot to 850 ° C. or higher, forging with a total cross-sectional reduction rate of 40% or more in each heat is performed to reduce the nickel segregation portion. The occurrence of the streak unevenness is suppressed.

Further, the technology disclosed in Japanese Patent Laid-Open No. 61-223188 controls the segregation rate and segregation zone of nickel by preventing segregation during ingot production or by performing nickel diffusion treatment by heat treatment during the strip manufacturing process. Thus, uneven etching streaks are suppressed.

[Problems to be Solved by the Invention]

However, the above-mentioned conventional technique disclosed in JP-A-60-128253 is characterized in that forging is performed so that the total cross-section reduction rate exceeds 40%, but generally this degree of work is normally performed. This is a load, and segregation of various elements is not easily eliminated by such a method, and thus it was insufficient to prevent the occurrence of streak unevenness during etching.

On the other hand, the above-mentioned conventional technique disclosed in Japanese Patent Laid-Open No. 61-223188 is characterized by reducing the segregation of its components through the diffusion of Ni by high temperature heat treatment, but the plate thickness is thinner than the heating at the slab stage. Therefore, there is a problem in that the oxidation loss is relatively large and the yield is significantly reduced.

Especially in the shadow masks for various displays that require high precision, the holes to be punched are about 1/2 the diameter of the holes in consumer television shadow masks, and the number is twice or more. Since the uniformity of the holes at the time of etching is directly affected, it is difficult to completely avoid the generation of streak unevenness. Therefore, the actual situation is that streak unevenness at the time of etching cannot be completely suppressed.

An object of the present invention is, in view of the circumstances of the art, an alloy material that does not cause streaking during etching, that is,
A method for advantageously producing a Fe-Ni alloy containing 30 to 80% Ni is being proposed.

[Means for Solving the Problems]

Therefore, the present inventors have made Fe-
Various studies were conducted on the streak unevenness of Ni-based alloys. As a result, it was found that the main causes of the uneven streaks found were component segregation of impurity elements such as C, Si, Mn, and Cr, and a difference in crystal structure.

For example, in the component segregated portion of the impurity element such as C, Si, Mn, and Cr, the etching speed changes as compared with the other portions, so that the difference in the hole shape is caused during the photoetching perforation, which causes streak unevenness. It will be.

On the other hand, regarding the difference in crystal structure, for example, (100)
A portion where a large number of planes are oriented has a higher etching rate than other portions, resulting in a difference in hole shape during photoetching perforation. This is the solidification structure during casting,
In other words, it is caused by the existence of a columnar structure having a specific orientation. This columnar structure is elongated in the rolling direction while changing its shape without disappearing in the subsequent processing and heat treatment steps, and finally causes the streak unevenness. It will be.

From this, in the present invention, an attempt was made to overcome the above-mentioned problems, aiming at not only suppression of component segregation but also adjustment of the crystal structure.

That is, as a means for overcoming the problem, the present invention provides Ni
After heating an ingot of Fe-Ni alloy containing ~ 80 wt% and the balance being mainly Fe to a temperature of 900 ° C or higher, it is subjected to swaging by a staking ratio of 1 / 1.5U or more, and then the total cross-section reduction rate. We propose a method for producing a Fe-Ni-based alloy that is excellent in the effect of suppressing streak unevenness during etching, which is characterized by performing hot forging at 50% or more.

[Work]

In the present invention, the lower limit of the Ni content of the material is set to 30 wt% (hereinafter simply abbreviated as “%”)
When using a Fe-Ni alloy as the above functional material,
This is because if the content is less than 30%, sufficient electromagnetic characteristics are not exhibited and it cannot withstand practical use. Conversely, if Ni exceeds 80%,
This is because the quality of electronic and electromagnetic materials deteriorates.

Next, the reason why the heating temperature of the ingot prior to forging is set to 900 ° C. or higher is that if the heating temperature is lower than 900 ° C., the forgeability deteriorates and the component segregation cannot be reduced. The upper limit of the heating temperature is, of course, a temperature that does not exceed the melting point.

In addition, the reason for setting the squeeze forming ratio (hereinafter referred to as the sue mixing ratio) in the swell mixing ratio to be 1 / 1.5U or more is that the sizing ratio is 1 /
This is because if it is less than 1.5 U, the crystals cannot be sufficiently homogenized and streaks occur. This will be described in more detail below.

That is, such streak unevenness is caused by the fact that the giant crystal grains having a specific orientation during casting are stretched in the rolling direction by rolling while changing their shapes without disappearing in the subsequent processing and heat treatment. I knew that. Moreover, according to the research conducted by the present inventors, when the crystal grains having a specific orientation when processed to the final plate thickness have short crystal grains,
The length was also relatively small, and no partial difference in etching rate occurred during etching perforation was observed, and therefore, no continuous streak unevenness was observed. However, in the case where the crystal grains have a long length, the ones corresponding to the width and the length of the crystal grains remain as they are even after the processing, that is, they remain large, which causes stripe unevenness during etching.

The length of the crystal grain, which is the limit of whether or not the streak unevenness appears, is determined by swaging, that is, if the swaging ratio is less than 1 / 1.5U, the length of the crystal grain becomes long and the streaking unevenness occurs. Will occur.

Next, the total cross-section reduction rate in the exercises following the above-mentioned suede exercise (including actual exercise and wrought exercise) was set to 50% or more because if it is less than 50%, the segregation of components due to forging is sufficiently reduced. This is because it is not done.

As described above, by forging the ingot of the Fe-Ni alloy under specific forging conditions, it is possible to suppress the streaking unevenness during the etching by homogenizing the crystal grains and reducing the segregation of the components, and therefore, an extremely excellent etching. It is possible to secure the sex.

〔Example〕

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

The alloys shown in Table 1 and specifically targeted by the present invention are obtained by melting molten metal in an electric furnace, followed by AOD method or VOD.
After refining by the method, ingots are ingot, then the first
After hot forging according to the conditions shown in the table to make a slab, hot rolling was carried out to make a 5.5 mm thick hot rolled plate, and then a coil. After the hot rolling, the final product was obtained by performing a treatment according to a conventional method in which cold rolling and heat treatment were appropriately combined according to a conventional method.

The test material produced in this manner was subjected to actual photoetching opening with a ferric chloride solution (specific gravity: 1.45, 50 ° C.) to investigate whether streaks occurred. The results are shown in Table 1.

As can be seen from Table 1, the Fe-Ni-based alloy produced according to the method of the present invention has more streaks during etching than the Fe-Ni-based alloy (comparative example) produced by the conventional method having the same composition. Almost no unevenness was observed, which revealed that the alloy was an excellent material for etching.

〔The invention's effect〕

As described above, Fe- produced by the method of the present invention
Ni-based alloys have no streaks after photo-etching and therefore have desirable properties as electronic and electromagnetic materials.
An Fe-Ni based alloy can be provided.

Claims (1)

[Claims] 1. An ingot of a Fe-Ni alloy containing 30 to 80 wt% of Ni and the balance being mainly Fe is heated to a temperature of 900 ° C. or higher, and then swaging is carried out at a wrought forming ratio of 1 / 1.5 U or more. And a hot forging with a total cross-sectional reduction rate of 50% or more.