KR20040080733A - Fe-Cr-Ni alloy for electrode of the electron gun - Google Patents

Abstract

PURPOSE: A Fe-Cr-Ni alloy for electrodes of electron gun is provided to prevent the lowering of drawing property and press property and to improve focus and convergence property by maintaining nonmagnetic property after performing a heat treatment. CONSTITUTION: An electron gun comprises a cathode, a control electrode, a screen electrode arranged at the front of the control electrode, a focus electrode, a final accelerating electrode, and a shield cup connected electrically to the final accelerating electrode. The focus electrode, the final accelerating electrode and the shield cup are constituted by Cr:18-20wt%, Ni:8-10wt%, C:less than 0.03wt%, Si:less than 1.00wt%, Mn:less than 2.00wt%, P:less than 0.04wt%, S:less than 0.005wt%, and the rest element containing Fe and impurity material. An average size of crystal grain of elements is 0.010 - 0.022mm.

Description

Fe-Cr-Ni alloy for electrode of the electron gun}

The present invention relates to an electron gun, and more particularly, to an iron-chromium-nickel-based alloy for electron gun electrodes, which has excellent drawing property and press formability, and which has improved non-magnetic properties such that focus characteristics and convergence drift characteristics are not deteriorated. It is about.

Typically, the cathode ray tube encloses an electron gun in the neck portion of the bulb, emits an electron beam from an electron gun to which a predetermined power is applied, and the emitted electron beam is selectively deflected by a deflection yoke provided in the cone portion of the bulb, thereby providing a screen surface. The fluorescent film of the phosphor applied to the inner surface of the panel to form the excitation to implement the image. The cathode ray tube employs various methods of connecting electron guns in order to reduce aberration components on the screen surface.

The electron gun includes a cathode which emits electrons, a control electrode, and a triode consisting of a screen electrode. At least one focus electrode group is continuously disposed in front of the screen electrode, and a final acceleration electrode is disposed in front of the last focus electrode among the focus electrode groups so as to face the screen electrode to form a main lens unit.

Among the electrodes of the electron gun, the electrodes forming the triode must have a low coefficient of thermal expansion, so a nickel-based superalloy is mainly used. Since the control and screen electrodes are mainly processed in plate type, excellent press working is required.

The electrodes other than the control and screen electrodes, in particular the electrodes forming the main lens portion, are mainly processed in a cup type. Such electrodes require deep drawing formability. The cup-shaped electrode must maintain nonmagnetic properties so as not to distort the deflection magnetic field, thereby degrading the focus characteristics and the convergence drift characteristics. In addition, the resistance to heat and corrosion must be excellent, and the amount of gas released must be small so as not to affect the vacuum in the cathode ray tube.

In general, a stainless steel alloy of SUS 305 series is used as a cup-type electrode material. However, the SUS 305 series stainless alloy steel has a problem that 12 to 16 percent of relatively expensive nickel (Ni) component must be included to satisfy deep drawing and nonmagnetic properties.

Therefore, it is necessary to reduce the manufacturing cost by lowering the content of the nickel component and to develop an electrode material having excellent drawing property and press formability required as an electron gun electrode.

The present invention is to solve the above problems, the present invention by adjusting the components and properties of the electron gun electrode, satisfies the drawing and pressing properties required as the electron gun electrode, and maintains the non-magnetic after heat treatment focus and control An object of the present invention is to provide an iron-chromium-nickel-based alloy for electron gun electrodes with improved version characteristics.

1 is a cross-sectional view showing a conventional cathode ray tube,

2 is an exploded perspective view illustrating the electron gun of FIG. 1;

3 is a cross-sectional view illustrating the main lens unit of FIG. 2;

Figure 4 is a graph showing the permeability according to cold working according to an embodiment of the present invention,

5 is a graph showing the tensile strength according to the average grain size of the electrode material according to an embodiment of the present invention,

6 is a graph showing the yield strength according to the average grain size of the electrode material according to an embodiment of the present invention,

7 is a graph showing the elongation according to the average grain size of the electrode material according to an embodiment of the present invention,

8 is a graph showing the plastic strain ratio according to the average grain size of the electrode material according to an embodiment of the present invention.

<Brief description of symbols for the main parts of the drawings>

10 ... cathode tube 11 ... panel

12 ... Funnel 13 ... Shadow Mask

14 ... shadow mask frame 15 ... stud pins

16 Hook 17 Shield Cup

18 ... deflection yoke 20 ... electron gun

21 ... cathode 22 ... control electrode

23 ... screen electrode 24 to 27 ... focus electrode

28.Final Acceleration Electrode

Iron-chromium-nickel-based alloy for an electron gun electrode according to an aspect of the present invention in order to achieve the above object,

A cathode, a control electrode, a screen electrode provided in front of the control electrode, at least one focus electrode provided to face the screen electrode to form a prefocus lens portion, and a main lens disposed to face the focus electrode. An electron gun including a final accelerating electrode forming a portion and a shield cup electrically connected to the final accelerating electrode,

The material for the focus and final acceleration electrode and the shield cup has a chemical composition ratio by weight% of chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, carbon (C): 0.03% or less, and silicon (Si) : 1.00% or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less, and the remainder are iron (Fe) and a small amount of impurities,

The average grain size of the material is characterized in that 0.010 to 0.022 millimeters.

In addition, the electrode material is characterized in that the surface roughness value is in the range of Ra: 0.05 to 0.2 micrometers, Rmax: 1.5 to 2.0 micrometers.

Where Ra is the arithmetic mean roughness and Rmax is the maximum roughness.

Iron-chromium-nickel-based alloy for an electron gun electrode according to another aspect of the present invention,

A cathode, a control electrode, a screen electrode provided in front of the control electrode, at least one focus electrode provided to face the screen electrode to form a prefocus lens portion, and a main lens disposed to face the focus electrode. An electron gun including a final accelerating electrode forming a portion and a shield cup electrically connected to the final accelerating electrode,

The material for the focus and final acceleration electrode and the shield cup has a chemical composition ratio by weight% of chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, carbon (C): 0.03% or less, and silicon (Si) : 1.00% or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less, and the remainder are iron (Fe) and a small amount of impurities,

In order to restore the ferromagnetic martensite structure produced by cold working to the original nonmagnetic austenite structure, annealing heat treatment was performed at a temperature of about 1000 ° C. or higher after electrode formation. It is done.

In addition, the average grain size of the electrode material is characterized in that 0.010 to 0.022 millimeters.

Further, the electrode material is characterized in that the surface roughness value is in the range of Ra: 0.05 to 0.2 micrometers, Rmax: 1.5 to 2.0 micrometers.

Where Ra is the arithmetic mean roughness and Rmax is the maximum roughness.

Hereinafter, an electron gun for a cathode ray tube according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the cathode ray tube 10 includes a panel 11 having a fluorescent film formed on an inner surface thereof, a funnel 12 coupled to the panel 11 to form a bulb, and an inside of the panel 11. It includes a shadow mask 13 is provided spaced apart a predetermined interval and the electron beam passes through the shadow mask 13, and the shadow mask frame 14 is fixed to the shadow mask (13).

The shadow mask frame 14 is formed inside the panel 11 by a stud pin 15 formed on an inner surface of the panel 11 and a hook spring 16 elastically supported by the stud pin 15. The position is determined at.

In the neck portion 12a of the funnel 12, an electron gun 20 for scanning an electron beam of red, green, and blue is enclosed in a fluorescent film formed inside the panel 11. A shield cup 17 is provided in front of the electron gun 20. The cone part 12b of the funnel 12 is provided with a deflection yoke 18 for deflecting the electron beam.

As shown in FIG. 2, the electron gun 20 includes a plurality of cathodes 21, which are emission sources of thermal electrons, a control electrode 22 installed in front of the cathode 21, and the control electrode 22. ), A plurality of focus electrode groups 24 to 27 provided in front of the screen electrode 23, and a last focus electrode of the focus electrode groups 24 to 27. And an anode electrode 28 which is installed to face 27. Prize

Three cathodes 21 are arranged inline so as to generate red, green, and blue hot electrons. The control electrode 22 controls the amount of electrons emitted from the cathode 21 by an external signal, and an independent small diameter electron beam through hole is formed. An independent small-diameter electron beam passing hole is formed in the screen electrode 23 so as to form the first focus electrode 24 and the prefocus lens unit, which are opposite electrodes.

At least one focus electrode 24 to 27 is disposed in front of the screen electrode 23 so as to face the screen electrode 23 to form an electron lens unit for focusing and accelerating the electron beam.

The number of the focus electrodes 24 to 27 is not limited to the above-mentioned number, and may be increased according to the formation of the electron lens unit for focusing the electron beam in multiple stages. In addition, three electron beam through holes are formed in an in-line shape so that electron beams for exciting red, green, and blue fluorescent films applied to the inner surface of the panel pass through each electrode, and the electron beam through holes are formed between the electrodes. It may vary depending on the size of the parts. In addition, the electrode may vary depending on the size of the electronic lens unit formed between the electrodes. In addition, a single large-diameter electron beam passing hole may be formed according to the electrode, and a small-diameter electron beam passing hole through which three electron beams pass may be formed.

The electron gun 20 having the above-described configuration has each electrode 22 to 28 in order to focus and accelerate the electrons generated from the cathode 21, which is the emission source of the hot electrons, through the electron beam passing holes formed in the electrodes 22 to 28. ), A predetermined voltage is applied.

The electron gun 20 emits hot electrons from the cathode 21 and controls the amount of electrons of the hot electrons by a potential difference between the cathode 21 and the control electrode 22. The electron beam accelerated while passing through the screen electrode 23 is focused on the fluorescent film by the focus electrodes 24 to 27 and the final accelerating electrode 28 to implement an image.

Here, the control electrode 22 and the screen electrode 23 is a plate-shaped electrode, other electrodes 24 to 28 except for this is a cup-shaped electrode.

Among them, referring to FIG. 3 illustrating the focus electrode 27 and the final acceleration electrode 28 forming the main lens unit, the focus electrode 27 and the final acceleration electrode 28 are formed in a cup form by pressing. Drawing and punching the electron beam passing holes 27a and 28a through which the electron beam can pass. Further, burring portions 27b and 28b are formed on the surface where the electron beam enters and exits.

According to a feature of the invention, the control electrode 22, other electrodes 24 to 28 except the screen electrode 23, and the shield cup 17 (see FIG. 1) installed in front of the electron gun 20 are It is made of austenitic stainless steel (Fe-Cr-Ni stainless steel) in which the content of nickel is smaller than the conventional case and the average grain size or surface roughness value is limited to a specific value.

More detailed description is as follows.

The alloy used for the electron gun electrode is composed of an iron-chromium-nickel-based alloy, and the chemical composition ratio is% by weight of chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, and carbon (C). : 0.03% or less, silicon (Si): 1.00% or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less and the remainder is iron (Fe) Austenitic iron-chromium-nickel (Fe-Cr-Ni) alloy.

The electron gun electrode material has an average grain size of about 0.01 to 0.02 millimeters in order to obtain excellent drawing property and to obtain dimensional accuracy and good appearance of the part.

In addition, the electrode material is mainly composed of a paramagnetic austenite structure in order to secure nonmagnetic properties so as not to degrade the focus characteristic and the convergence characteristic of the electron gun. In order to be composed of such a microstructure, the chemical composition ratio is by weight% chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, carbon (C): 0.03% or less, silicon (Si): 1.00 % Or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less and the remainder of the austenitic iron consisting of iron (Fe) and a small amount of impurities It is a chrome-nickel (Fe-Cr-Ni) alloy.

The electrode material having such a content ratio is annealed at a temperature of about 1000 ° C. or higher after electrode formation to restore the ferromagnetic martensite structure produced by cold working to the original nonmagnetic austenite structure. annealing).

That is, the electrode material of the present invention becomes magnetic as the rolling rate or cold working amount increases, but recovers to the original cold working 0% state by performing an annealing heat treatment at a temperature of about 1050 ° C. after forming the electrode, thereby making it nonmagnetic. It is possible to be satisfied.

It is composed of an austenite structure in which the microstructure of the electrode material has nonmagnetic properties. The structure is changed to a microstructure of ferromagnetic martensite by a deformation mechanism called strain organic martensite transformation during cold working, but after heat treatment This is because it is restored to its original microstructure.

In this case, when the nickel content of the electrode material is 8% or less, the undeformed magnetic structure remains after heat treatment, and considering that nickel is expensive, the nickel content is preferably in the range of 8 to 10%.

On the other hand, the surface roughness of the electrode material influences the drawing property by affecting the coefficient of friction between the die punch and the die, and is also related to the gas release characteristics of the surface and the appearance of the final part. In particular, in order to satisfy the appearance and formability of the final part, roughness of a suitable height is essential. To this end, a brush finishing process is performed on the surface of the electron gun electrode material to form a specific range of surface roughness.

Accordingly, the surface roughness value of the electrode material has a range of Ra: 0.05 to 0.2 micrometer and Rmax: 1.5 to 2.0 micrometer. Ra is an arithmetic mean roughness, and Rmax is the maximum roughness.

Outside the above range, the lubrication action is insufficient and wear occurs badly. In particular, it is preferable that the form of surface roughness formed by the surface treatment has a continuous dotted form rather than a continuous straight form so as to reduce the anisotropy of the electrode material.

Hereinafter, the characteristics of the electrode material of the present invention according to the applicant's experiment will be described.

Table 1 shows the composition ratio of the conventional electrode material, the electrode material of the present invention, and the average grain size.

Kinds Carbon (C) Silicon (Si) Manganese (Mn) Phosphorus (P) Sulfur (S) Nickel (Ni) Chrome (Cr) Fe Average grain size (mm) Conventional example 0.04 0.68 1.61 0.021 0.002 14.12 16.13 Bal. 0.019 Comparative Example 1 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.030 Comparative Example 2 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.025 Comparative Example 3 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.019 Comparative Example 4 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.013 Comparative Example 5 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.008 Comparative Example 6 0.02 0.62 1.21 0.025 0.003 9.48 18.55 Bal. 0.002

Here, the conventional electrode material (conventional example) is SUS 305 series stainless alloy steel, and the electrode material (Comparative Examples 1 to 6) of the present invention is an austenitic stainless alloy steel in which the composition ratio of components is adjusted to a specific range.

Referring to the table, the conventional electrode material has a nickel content of 14.12%, while the electrode material of the present invention has a nickel content of 9.48%. The electrode material of the present invention is 0.03% or less in order to reduce the amount of carbide deposited on the grain boundaries of the material, while the conventional electrode material has a carbon content of 0.4%. Such carbon content can improve the corrosion resistance and brittleness of the electrode material.

In this case, the grain size refers to the size of the austenite grains separated by the grain boundary (microstructure) inside the stainless alloy steel.

The result of having measured the characteristic using the electrode material of this invention which has the above-mentioned composition ratio is as follows.

4 shows the change in permeability according to the cold working rate of the electrode material with respect to nickel content.

Here, the X axis represents cold working rate and the Y axis represents permeability.

Referring to the drawings, the cold working rate is when the nickel content is 12% (A curve) or when the nickel content is 8.0% (C curve) than when the nickel content is 9.5% (B curve). As this increased, the permeability increased rapidly.

That is, when the nickel content is about 8% or less, it can be seen that the permeability increases rapidly as the cold working rate increases. Here, the permeability is a value indicating how easily the magnetic force lines pass through the material. In the case of a ferromagnetic material, the magnetic force lines entering the material do not penetrate unless they cause magnetic saturation, whereas in the case of nonmagnetic materials, the magnetic force lines do not block Without penetrating easily. At this time, when the permeability is 1, the permeability in vacuum means. Therefore, in order not to deteriorate the focus characteristic of an electron gun by not affecting a deflection magnetic field, it is preferable that permeability is close to one.

5 to 7 show regression results of mechanical properties of tensile strength, yield strength, and elongation according to changes in average grain size of an electrode material according to one embodiment of the present invention.

5 to 7, as the average grain size increases, the tensile strength and the yield strength of the electrode material decrease nonlinearly, while the elongation tends to increase.

At this time, the plastic deformation ratio, R value proposed by Lankford is used to evaluate the formability of the material according to the change of the average grain size.

Here, epsilon _w is a deformation | transformation of the width direction, and epsilon _t is a deformation | transformation of a thickness direction. W _f and W ₀ are width dimensions before and after deformation of the material, and t _f and t ₀ are thickness dimensions before and after deformation of the material. W ₀ l ₀ is an interval in the width and depth directions before the tensile test, and W _f l _f is an interval in the width and depth directions after the 18% stretching.

The plastic strain ratio R is a factor for evaluating the unstable plastic behavior of the electrode material during forming, i.e., the onset of necking caused by the thinning in the localized area. In the rolling direction, the deformation resistance is low and the deformation is good, whereas in the thickness direction, the deformation resistance is large, which means that the necking phenomenon is less likely to occur. Therefore, when R value is large, drawing property is excellent.

The electrode material of the present invention mainly consists of austenite structure, and the R value for an alloy steel having a face centered cubic structure (FCC) such as austenite structure can be obtained from multiple regression equations as follows.

Here, TS is Tensile strength (MPa), YS is Yield Strengh (MPa), n is strain hardening exponent, and EL is Elongation (%).

In the case of the electrode material according to the comparative example of the present invention, the n value is about 0.5, and the calculated R value according to the change of the average grain size using the above equation is shown in FIG. 8, and FIGS. 5 to 8. Table 2 shows the contents of.

Average grain size Tensile Strength (TS) Yield strength (YS) Elongation (EL) R value Dimensional Accuracy Burring R part 0.033 593.7 238.0 64.3 0.97 △ × 0.030 594.9 237.2 62.5 0.96 △ × 0.028 598.7 239.0 60.7 0.95 △ △ 0.025 605.2 243.5 59.1 0.94 △ △ 0.022 614.4 250.8 57.5 0.93 ○ ○ 0.019 626.2 260.7 56.0 0.93 ○ ○ 0.016 640.8 273.3 54.6 0.92 ○ ○ 0.013 658.0 288.6 53.3 0.91 ○ ○ 0.010 677.9 306.6 52.1 0.90 ○ ○ 0.008 700.4 327.3 50.9 0.90 △ ○ 0.005 725.7 350.7 49.9 0.89 △ ○ 0.002 753.6 376.8 48.9 0.89 △ ○

8 and Table 2, the plastic strain ratio R value tends to increase as the average grain size increases, but considering the dimensional accuracy after the electrode molding and the appearance of the burring R portion, the average grain size is 0.010 to 0.022. It is preferred to be in the range of millimeters.

As described above, the electrode material of the present invention adjusts the composition ratio in a specific range in the iron-chromium-nickel-based alloy, and limits the average grain size and the surface roughness value to specific values.

As described above, the iron-chromium-nickel-based alloy for an electron gun electrode of the present invention can obtain the following effects.

In the iron-chromium-nickel alloy steel used as the electrode material of the electron gun, the cost of manufacturing the electron gun can be greatly reduced by lowering the expensive nickel content to a certain range. In particular, it has excellent drawing property and press formability required as the electron gun electrode. On the other hand, by having a non-magnetic so as not to reduce the focus characteristic and the convergence drift characteristic, the reliability conditions of the cathode ray tube can be satisfied.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

A cathode, a control electrode, a screen electrode provided in front of the control electrode, at least one focus electrode provided to face the screen electrode to form a prefocus lens portion, and a main lens disposed to face the focus electrode. An electron gun including a final accelerating electrode forming a portion and a shield cup electrically connected to the final accelerating electrode, The material for the focus and final acceleration electrode and the shield cup has a chemical composition ratio by weight% of chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, carbon (C): 0.03% or less, and silicon (Si) : 1.00% or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less, and the remainder are iron (Fe) and a small amount of impurities, Iron-chromium-nickel-based alloy for electron gun electrode, characterized in that the average grain size of the material is 0.010 to 0.022 millimeters. The method of claim 1, The electrode material has a surface roughness value of Ra: 0.05 to 0.2 micrometers, Rmax: iron-chromium-nickel-based alloy for electrode, characterized in that the range of 1.5 to 2.0 micrometers. Where Ra is the arithmetic mean roughness and Rmax is the maximum roughness. A cathode, a control electrode, a screen electrode provided in front of the control electrode, at least one focus electrode provided to face the screen electrode to form a prefocus lens portion, and a main lens disposed to face the focus electrode. An electron gun including a final accelerating electrode forming a portion and a shield cup electrically connected to the final accelerating electrode, The material for the focus and final acceleration electrode and the shield cup has a chemical composition ratio by weight% of chromium (Cr): 18 to 20%, nickel (Ni): 8 to 10%, carbon (C): 0.03% or less, and silicon (Si) : 1.00% or less, manganese (Mn): 2.00% or less, phosphorus (P): 0.04% or less, sulfur (S): 0.005% or less, and the remainder are iron (Fe) and a small amount of impurities, In order to restore the ferromagnetic martensite structure produced by cold working to the original nonmagnetic austenite structure, annealing heat treatment was performed at a temperature of about 1000 ° C. or higher after electrode formation. Iron-chromium-nickel alloy for electron gun electrodes. The method of claim 3, wherein Iron-chromium-nickel-based alloy for electron gun electrode, characterized in that the average grain size of the electrode material is 0.010 to 0.022 millimeters. The method of claim 3, wherein The electrode material has a surface roughness value of Ra: 0.05 to 0.2 micrometers, Rmax: iron-chromium-nickel-based alloy for electrode, characterized in that the range of 1.5 to 2.0 micrometers. Where Ra is the arithmetic mean roughness and Rmax is the maximum roughness.