JP3401307B2 - Material for shadow mask excellent in recrystallization characteristics and manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to F which is excellent in recrystallization characteristics.
The present invention relates to an e-36% Ni-based shadow mask material and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a picture tube such as a cathode ray tube for a color television or a display for an office automation equipment, a shadow mask having a large number of electron beam passage holes is incorporated. The electron beam emitted from the electron gun passes through a specific electron beam passage hole and projects a beam spot on each fluorescent portion according to each color tone. As the material for the shadow mask,
Low carbon Al killed steel has been conventionally used, which is required to have excellent etching properties so that an accurate electron beam passage hole is formed. But the shadow mask
It is heated by the collision of the electron beam and causes thermal expansion. The thermal expansion causes a so-called doming phenomenon in which the electron beam passage hole is displaced and the electron beam does not hit a predetermined phosphor screen. The doming phenomenon has become a big problem as the precision and brightness of televisions and displays have become higher. Since the doming phenomenon is suppressed by using a material having a low thermal expansion characteristic, Fe-36% Ni amber alloy is beginning to be used as a shadow mask material (Japanese Patent Laid-Open No. 61-78033). 4-
56107, etc.).

However, since the Fe-36% Ni amber alloy contains a large amount of Ni, the material price is higher than that of the low carbon Al killed steel, and the strength is higher than that of the low carbon Al killed steel. , Inferior in press moldability. Also, the Young's modulus is low and the rigidity as a shadow mask is poor,
There are drawbacks such as slow etching rate and poor etching piercing property. In this regard, in Japanese Patent Publication No. 4-56107, addition of B increases the (100) plane occupancy to improve the etching property, and Cr is added to reduce the yield strength. As a result, although the press formability and the etching property are improved, when the etched material is used as a shadow mask, there is a problem in terms of quality such as inferior blackening film. In addition, Japanese Patent Laid-Open No. 1-252725
In the publication, a homogenizing heat treatment eliminates the segregation of Ni and introduces a Fe-Ni alloy for a shadow mask, which is free from streaks and has excellent etching properties.

[0004]

The addition of B is (100)
Although it is effective in increasing the surface occupancy and improving the etching property of the Fe-Ni alloy, it has a serious problem of deteriorating the adhesion of the blackened film formed after the etching. Recently, since there is a strong demand for adhesion of a blackened film, Fe- for a shadow mask without adding B is used.
A 36% Ni alloy is sought. However, simply omitting the addition of B deteriorates the recrystallization characteristics after softening and annealing as compared with the B-added material. Therefore, a defective shape is likely to occur during the subsequent press molding. The present invention has been devised to solve such a problem. By subjecting a Fe-Ni alloy containing no B to a heat treatment under specific conditions after hot rolling, recrystallized grains are made large and uniform. An object of the present invention is to obtain a material for a shadow mask excellent in warm pressability by growing and imparting good recrystallization characteristics by finish annealing after the subsequent cold rolling.

[0005]

In order to achieve the object, the shadow mask material excellent in recrystallization characteristics of the present invention is Ni: 34 to 39% by weight, Cr: 4% by weight or less, S:
i: 0.4 wt% or less and Mn: 1 wt% or less,
C: 0.01 wt% or less, N: 0.01 wt% or less,
O: 0.01 wt% or less and B: 0.001 wt% or less of an Fe-Ni-based alloy, the crystal grains of which are JI
It is characterized in that it is sized to SNo. Such a shadow mask material having excellent recrystallizing properties is 1000 to 1 after hot-rolling the Fe-Ni alloy having the above composition.
It can be manufactured by annealing at a high temperature of 200 ° C., followed by cold rolling and finish annealing.

[0006]

The shadow mask is usually manufactured in the following steps. Melting → Agglomeration → Hot rolling → Pickling → Cold rolling → Bright annealing → Cold rolling → Etching → Softening annealing →
Press processing → Blackening treatment By press molding performed prior to the formation of the blackening film, F
The e-Ni alloy is formed into a shadow mask shape having a predetermined curved surface while being kept at a temperature of around 200 ° C. In the formed Fe-Ni alloy, shape defects such as a hook-and-loop dent may occur. It is speculated that these defects are caused by an insufficient recrystallized structure during bright annealing.

Therefore, the present inventors have investigated and studied the improvement of the recrystallized structure from various viewpoints. As a result, it was found that it is effective to anneal the hot-rolled Fe-Ni alloy at a high temperature of 1000 to 1200 ° C. so as to adjust the structure to a grain size controlled to large crystal grains of JIS No. 5 to 6. I found it. Fe-Ni having this sized recrystallized structure
The alloy exhibits good recrystallization characteristics by cold rolling-finish annealing and becomes a shadow mask material having good shape characteristics when subjected to warm press forming after etching. F used in the present invention
The e-Ni alloy contains Ni: 34 to 39% by weight and Cr: 0 to
1 wt%, Co: 0 to 3 wt%, Si: 0.4 wt% or less and Mn: 1 wt% or less, C: 0.01 wt% or less, N: 0.01 wt% or less and O: 0. It is regulated to 0.01% by weight or less, and B: 0.001% by weight or less.

Ni: 34 to 39 wt% This is an important alloying element for keeping the coefficient of thermal expansion of the Fe-Ni alloy low. When the Ni content is out of the range of 34 to 39% by weight, the coefficient of thermal expansion increases, and the thermal deformation easily causes the doming phenomenon. Cr: 4% by weight or less Although it has an effective effect of increasing the etching rate of the Fe-Ni alloy, it has a drawback of increasing the thermal expansion coefficient. Therefore, when Cr is added, the Cr content is restricted to a range of 4% by weight or less. Si: 0.4 wt% or less Similar to C, it has the effect of increasing the coefficient of thermal expansion. Therefore, in the present invention, the upper limit of the Si content is 0.4
Specified in% by weight. Mn: 1% by weight or less An element added as a deoxidizing material, and 0.01% by weight or more is necessary to obtain a predetermined deoxidizing effect. But,
When an excess amount of Mn exceeding 1% by weight is contained, Fe-N
The coefficient of thermal expansion of the i-based alloy increases. Therefore, in the present invention, the Mn content is limited to 1% by weight or less.

B: 0.001% by weight or less It is an element which causes unevenness in the formation of a blackened film by the blackening treatment and impairs the quality stability as a shadow mask. Therefore, in the present invention, it is necessary to strictly limit the B content, and the upper limit is set to 0.001% by weight. C: 0.01% by weight or less Carbides are formed and etching piercing property is deteriorated. It is necessary to strictly limit the C content in order to obtain excellent etching properties, and in the present invention, the upper limit of the C content is specified to be 0.01% by weight, preferably 0.005% by weight. N: 0.01% by weight or less In order to form a nitride-based inclusion and significantly reduce the etching piercing property, the upper limit of the N content is specified to be 0.01% by weight. 0: 0.01% by weight or less Oxide inclusions are formed, and the etching piercing property is significantly reduced. Therefore, in the present invention, the upper limit of the O content is specified to be 0.01% by weight. Co: 3.0 wt% or less It is an alloying element that has an effective action of increasing the etching rate like Cr and is added as necessary. The effect of adding Co saturates at 3.0% by weight, and adding more than that increases the material cost. Therefore, when Co is added, the Co content is set in the range of 3.0% by weight or less.

Fe-containing the alloying elements defined above
The Ni alloy is heat-treated by annealing at a high temperature of 1000 to 1200 ° C. This heat treatment is carried out under the condition that the recrystallized structure is sufficiently grown so as to be sized into large crystal grains of JIS No. 5-6. The Fe-36% Ni alloy after heat treatment exhibits a good recrystallized structure by finish annealing after cold rolling, the elongation and tensile strength are increased, and the workability in which hardness and 0.2% yield strength are decreased is good. It will be in a state. As will be apparent from the examples described later, the change in the characteristics due to the heat treatment is not found in the Fe-36% Ni alloy containing B, and is unique to the alloy system specified in the present invention. However, when the heat treatment temperature is lower than 1000 ° C., no characteristic change affecting the improvement of workability is observed. Also 1200 ° C
A heat treatment temperature exceeding 10 is not practical in terms of heat resistance of heating equipment and energy consumption. The heating time is set between 0.1 and 10 minutes in relation to the heat treatment temperature.

[0011]

【Example】

Example 1: A Fe-36% Ni alloy having the composition shown in Table 1 was melted and a hot rolled plate having a plate thickness of 6 mm was manufactured through a lumping process.
The comparative example is an Fe-Ni alloy containing B exceeding the upper limit regulated by the present invention. The hot-rolled sheet according to the present invention had the structure shown in FIG. 1 and had a hardness of 140 HV.

[0012]

[Table 1]

The hot rolled sheet was annealed, or cold rolled and finish annealed without annealing. In the annealing prior to cold rolling (hereinafter referred to as pre-annealing), the hot rolled sheet is
Heated to a temperature of 00 ° C. for 3 minutes. Then, the plate thickness was reduced from 6 mm to 0.3 mm by cold rolling, and finish annealing was performed by heating at 900 ° C. for 30 seconds in a non-oxidizing atmosphere. As shown in FIG. 1, the pre-annealed hot rolled sheet has a recrystallized structure in which crystal grains are sized according to JIS No. 5.5. When this pre-annealed hot-rolled sheet is subjected to cold rolling and finish annealing, a grain-sized and good recrystallized structure can be obtained.
On the other hand, in the case where the hot-rolled sheet was cold-rolled and finish-annealed without being pre-annealed, a recrystallized structure could not be obtained, and a streak pattern remarkably occurred. The difference in structure affects tensile properties represented by proof stress, tensile strength, elongation, and the like. That is, as shown in Table 3, by performing the pre-annealing prior to the finish annealing, the elongation δ is significantly increased and the tensile strength is also increased. On the contrary, the 0.2% proof stress decreases. in this way,
It can be seen that the alloys of the examples of the present invention have a large elongation and a small 0.2% proof stress as compared with the alloys of the comparative examples, and therefore exhibit good workability.

Example 2 A shadow mask was produced from the alloys whose compositions are shown in Table 1 through the following steps. 900 ° C. The hot rolling before annealing 800-1200 3 minutes soaking cold rolling thickness 6mm in ° C. to 0.3mm in thickness 6mm hot rolling finish rolling temperature 800 ° C. with thickness decreasing finish annealing H ₂ -N ₂ atmosphere the plate material after formation anneal etching the oblong holes of diameter 0.1mm in pitch 0.2mm in 30 seconds thickness decreasing etching FeCl ₃ solution heated cold-rolled thickness of 0.3mm to 0.25mm 780 Heat press forming at 55 ℃ for 55 minutes Molding softened and annealed sheet material at a temperature of 200 ℃ into a shadow mask shape Blackening treatment Heated at 600 ℃ for 15 minutes Recrystallization characteristics, pressability and blackening after finish annealing of the obtained material The membranous property was investigated. The recrystallization property was judged by observing the L cross section of the material after finish annealing with an optical microscope, examining the sizing condition, streak pattern, grain size, etc., and judging by its quality. With regard to pressability, it was investigated whether or not there was a defect in shape when it was formed into a shadow mask. Regarding the blackening film property, the adhesion property of the blackening film was investigated by a tape peeling test of the R part after the contact bending. The survey results are shown in Table 2.

[0015]

[Table 2]

As is clear from Table 2, the shadow masks of Test Nos. 1 to 3 produced according to the present invention are excellent in all of recrystallization characteristics, press moldability and blackening film formation. Further, as shown in Table 3, the materials of test numbers 1 to 3 satisfied the mechanical properties required for the shadow mask. However, even for the Fe-36% Ni alloy containing no B, the shadow mask of Test No. 4 not subjected to pre-annealing and the test mask No. 5 subjected to pre-annealing in which the heating temperature is too low.
As seen in No. 2, if recrystallization was insufficient, recrystallization became poor even after finish annealing, and press formability was poor. On the other hand, the shadow masks of Test Nos. 6 and 7 obtained from the Fe-36% Ni alloy containing B had good press formability, but were inferior in blackening film property.

[0017]

[Table 3]

[0018]

As described above, in the present invention, the Fe-Ni alloy is pre-annealed between hot rolling and cold rolling to sufficiently develop the recrystallization structure. In the pre-annealed Fe-Ni alloy, the crystal grains are sized according to JIS No. 5 to 6, and a good recrystallized structure is formed even after cold rolling and finish annealing. The obtained Fe-Ni alloy exhibits excellent press formability because of its large elongation and low yield strength, and is formed into a shadow mask having a predetermined shape without causing defects such as defective shapes. Moreover, since B is not added, it has excellent adhesion to the blackening film and is used as a material suitable as a cathode ray tube for televisions, a display for OA equipment, and the like, which fully utilizes low thermal expansion characteristics.

[Brief description of drawings]

FIG. 1 Structure of Fe-Ni alloy in each stage of hot rolling, pre-annealing, cold rolling and finish rolling

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-252725 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22C 38/00 C21D 6/00 C21D 8 / 00 H01J 9/14

Claims (2)

(57) [Claims] 1. Ni: 34 to 39% by weight, Cr: 4% by weight
% Or less, Si: 0.4% by weight or less and Mn: 1% by weight or less
Including below, C: 0.01% by weight or less, N: 0.01% by weight
% Or less, O: 0.01 weight% or less and B: 0.001 weight
It consists of Fe-Ni alloy regulated to less than the amount%, and crystallizes.
The feature is that the grains are sized according to JIS No. 5-6.
A material for shadow masks with excellent recrystallization properties. 2. Ni: 34 to 39% by weight, Cr: 4% by weight
% Or less, Si: 0.4% by weight or less and Mn: 1% by weight or less
Including below, C: 0.01% by weight or less, N: 0.01% by weight
% Or less, O: 0.01 weight% or less and B: 0.001 weight
After hot-rolling the Fe-Ni-based alloy regulated to a quantity% or less,
It seems that the crystal grains are sized and coarsened according to JIS No. 5-6.
, Annealed at a high temperature of 1000 to 1200 ° C., then cold
Recrystallization characteristics characterized by rolling and finish annealing
An excellent method for producing a shadow mask material.