WO2003106721A1

WO2003106721A1 - Low-thermal expansion alloy thin sheet and its manufacturing method

Info

Publication number: WO2003106721A1
Application number: PCT/JP2003/003047
Authority: WO
Inventors: 小林　聡雄; 山内　克久; 松岡　秀樹; 冨田　邦和; 村田　宰一
Original assignee: Ｊｆｅスチール株式会社
Priority date: 2002-06-18
Filing date: 2003-03-14
Publication date: 2003-12-24
Also published as: JP2004018959A; TW200400272A

Abstract

A low-thermal expansion alloy thin sheet wherein the sheet substantially comprises 30 to 34 mass% of Ni, 2 to 6 mass% of Co, 0.02 mass% or less of C, 0.3 mass% or less of Si, 0.6 mass% or less of Mn, 0.01 mass% or less of P, 0.005 mass% or less of S, 0.01 mass% or less of N, 0.1 mass% or less of Al, 0.08 mass% or less of Cr, 0.01 to 1 mass% of Ta or at least two elements selected from {0.05 to 1 mass% of Nb, 0.01 to 1 mass% of V, and 0.01 to 1 mass% of Ta}, and the balance of Fe, and (Nb+V+Ta)≤1 mass%. The sheet has a sufficiently low coefficient of thermal expansion, a 0.2 % offset yield strength of 300 to 350 MPa after it is softened below 850°C before the press, and a maximum permeability of 5,000 or more. Therefore, the sheet is preferable to a shadow mask of a cathode-ray tube.

Description

TECHNICAL FIELD The present invention relates to an Fe—Ni—Co-based low thermal expansion alloy sheet used for a shadow mask of a cathode ray tube and a method for producing the same. Kyogyo CRT shadow masks are made by etching the alloy thin plate of the material to form holes that allow the electron beam to pass through, and softening annealing before press to make it easier to form, and press forming according to the shape of the CRT. After that, it is assembled into a cathode ray tube.

Conventionally, Fe-Ni alloy thin plates have been known as a material for a shadow mask of a cathode ray tube. Since this alloy has a lower coefficient of thermal expansion than mild steel, it is heated by electron beam irradiation, causing deformation of the shadow mask due to thermal expansion. The phenomenon that color misregistration occurs because it does not hit the predetermined position is unlikely to occur. Indeed, the present inventors have found that 20 of the Fe- Ni-based alloy sheet:. L00 If the average thermal expansion coefficient in ° C is 0 8 X 10- ⁶ Pa C or less, de one timing is less likely to occur, further 0 if. 5 X 10_ ⁶ / ° C or less, it was confirmed that no happening command and ho is de one timing.

However, the Fe-Ni alloy thin plate has a problem that the shadow mask surface is easily dented due to shocks such as vibration when transporting the cathode ray tube, thereby causing color shift.

The impact resistance of such shadow masks can be improved by using Fe-Ni-Co alloy thin sheets that provide a lower coefficient of thermal expansion, but cathode ray tubes that use them have insufficient magnetic shielding properties, and There is a problem that a color shift due to the deviation occurs. Also, its impact resistance is not always sufficient.

Japanese Patent Application Laid-Open No. 2001-303200 discloses that, by controlling the amount of (, N, Nb), high strength is achieved without impairing the etching property and press punching property, and an improvement in impact resistance can be expected. Disclosed are Fe-Ni-based alloy sheets and Fe-Ni-Co-based alloy sheets, specifically: Ni: 24 to 47, Co: 22 or less, C: Hi.01¾ or less, N: 0.002 to Fe-Ni (-Co) alloy thin plate containing 0.02, b: 0.05 to 0.1% and having a balance of 15 or substantially Fe force, and 0.000013≤NbXN≤0.002. In the alloy thin plate described in JP-A-2001-303200, the rigidity of the shadow mask is improved by a high Young's modulus, but a high magnetic permeability cannot be obtained stably, and the magnetic shielding properties of the shadow mask are insufficient. In addition, in such a b-added Fe-Ni (-Co) alloy, recrystallization and subsequent growth of crystal grains are difficult to proceed. When applying a thin plate to a shadow mask, pre-press annealing at a high temperature of 850 ° C or higher is required, but from the viewpoint of manufacturing cost, a material that can be softened even in a temperature range below 850 ° C is desired. DISCLOSURE OF THE INVENTION The present invention has a sufficiently low coefficient of thermal expansion, and has excellent impact resistance and magnetic shielding properties after soft mask annealing before shaping at a temperature of less than 850 ° C and after shading of a shadow mask. It is an object of the present invention to provide an Fe-Ni-Co-based low thermal expansion alloy sheet and a method for producing the same, which substantially include, by mass, Ni: 30 to 34%, Co: 2 to 6%, C: : 0.02 or less, Si: 0.3 or less, Mn: 0.6% or less, P: 0.01% or less, S: 0.005 or less,: 0.01 or less, A1: 0.1 or less, Cr: 0.08 or less, Ta: 0.01 to 1% Nb: 0.05 to 1%, V: 0.01 to 1%, Ta: 0.01 to 1%} and at least two elements selected from the group consisting of And it can be achieved by (Nb + V + Ta) ≤1 Ru in which a low thermal expansion alloy sheet. PC leak 47

Three

These low-thermal-expansion alloy sheets are subjected to a step of repeating cold rolling and recrystallization annealing at least once or more on a hot-rolled sheet having the above components, and after the final recrystallization annealing, a final cold-rolling rate of 15 or more. The method can be realized by a method of manufacturing a low thermal expansion alloy sheet including a step of performing cold rolling and a step of performing 'strain relief annealing at 800 ° C or less after final cold rolling. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the relationship between 0.2 power resistance (0.2 PS) after soft annealing before press and maximum magnetic permeability (^ max).

FIG. 2 is a diagram showing the relationship between the softening annealing temperature before pressing and 0.2 heat resistance (0.2 PS). MODES FOR CARRYING OUT THE INVENTION The present inventors have studied the impact resistance and magnetic shielding properties of a shadow mask using a Fe-Ni-Co alloy thin plate, and have found the following.

1) The impact resistance and magnetic shielding properties of the shadow mask can be evaluated by the 0.2 resistance after softening and annealing and the maximum magnetic permeability, respectively.

2) If the 0.2 proof stress after softening annealing before pressing is 300 MPa or more, the incidence of dents is significantly reduced in the impact test after shadow mask molding, but if the 0.2% proof stress exceeds 350 MPa, shadow Press forming of the mask itself becomes difficult.

3) If the maximum magnetic permeability is 5000 or more, in the magnetic shield test after etching, the infiltration magnetic flux is remarkably small.

4) The 0.2 maximum magnetic permeability after softening annealing before pressing can be obtained by Ta alone or by adding at least two elements selected from Mb, V and Ta.

5) A larger maximum permeability can be obtained by adding at least one element of B and Sb.

The details are described below.

1. Ingredients Ni, Co: Ni and Co are essential elements to obtain low thermal expansion. Ni is 30-34, Co: 2-6¾ (It is necessary to rub.

C: Since C deteriorates the etching property and the low thermal expansion property, the content is set to 0.02% or less, preferably 0.005 or less, and more preferably less than 0.003.

Si: Si has a low thermal expansion property, which is not more than 0.3%, preferably not more than 0.09, in order to degrade the blackening property of the shadow mask.

Mn: Mn is set to 0.6 or less, preferably 0.1 or less, because it deteriorates the low thermal expansion property. Since n is an element effective for deoxidation and hot workability of the alloy, it is preferably 0.01 or more.

P: Since P deteriorates the etching property, the content is set to 0.01 or less.

S: S is set to 0.005 or less because it precipitates as sulfide and degrades the hot workability of the alloy.

N: N, when contained together with elements such as Al, Nb, and V, precipitates as nitride and degrades the etchability, and also deteriorates the hot workability of the alloy. The following is assumed.

A1: A1 precipitates as precipitates such as nitrides and oxides, deteriorating the magnetic shield property of the shadow mask and the low thermal expansion property, and also deteriorating the hot workability of the alloy. Preferably, it is 0.04% or less. A1 also has the effect of reducing inclusions in the alloy during smelting, and is therefore preferably 0.005 or more.

Cr: Cr precipitates as charcoal debris, nitride, etc. and degrades the magnetic shielding properties of the shadow mask. Since Cr also deteriorates the low thermal expansion property, it is desirable to reduce it as much as possible.

Nb: Nb improves the impact resistance and magnetic shielding properties of shadow masks when added in combination with the following V and Ta. For that purpose, Nb is required to be 0.05 or more, but is set to 1 or less, and preferably 0.6 or less to deteriorate the low thermal expansion property.

V: V, as described above, improves the impact resistance and magnetic shielding properties of the shadow mask when added in combination with Nb or Ta. For this purpose, V needs to be 0.01, but is set to 1 or less, preferably 0.6 or less in order to reduce the low thermal expansion property. Ta: Ta is the most important element in the present invention, and when added alone or in combination with V or Nb, it improves the impact resistance and magnetic shield property of the shadow mask. For this purpose, Ta needs to be 0.01, but is set to 1 or less, and preferably 0.6 or less, in order to lower the low thermal expansion property.

Furthermore, if a large amount of Nb, V, and Ta are added in combination, the 0.2% heat resistance after softening annealing before pressing exceeds 350 MPa, making press forming difficult, so that (Nb + V + Ta) is preferably 1% or less. More preferably, it should be 0.6 or less.

The balance is substantially Fe. That is, other elements may be contained as long as the effects of the present invention are not impaired.

Like this, substantial [Ni, 30 to 34%, Co: 2 to 6%,: 0.02% or less, Si: 0.3% or less, Mn: 0.6% or less, P: 0.01 or less, S: 0.005 or less, N : 0.01% or less, A1: 0.1% or less, Cr: 0.08% {T, Ta: 0.01 to l or ½; {Nb: 0.05 to: L%, V: 0.01 to 1, Ta: 0.01 to 1%} at least one element selected from Ri consists Oyopi ¾ portion Fe, and (Nb + V + Ta) by a ≤L%, doming is unlikely to occur 0.8X10- ⁶ Pas C following heat J3 Peng Zhang coefficient is obtained. In addition, C: 0.005% or less, Si: 0.09 or less, Mn ··· 0.01 to 0.1, A1: 0.005 to 0.04%, Nb: 0.05 to 0.6, V: 0.01 to 0.6, Ta: 0.01 to 0.6%, and ( with nb + V + Ta) Ru ≤0.6, doming Ho Tondo occur such lesゝ0.5X10- ⁶ / less thermal expansion coefficient is obtained.

Pre-press softening if at least one of B and Sb, which has the function of homogenizing crystal grains, is added to the above components, at least 0.0005 for B and 0.0015% for Sb A greater maximum permeability is obtained after annealing. At this time, there is a necessary force S to make B less than 0.003, Sb less than 0.010, and (2B + Sb) 0.001 to 0.010 so as not to deteriorate the blackening processability of the shadow mask.

2. Manufacturing method

The low-thermal-expansion alloy thin sheet of the present invention includes a step of repeating cold rolling and recrystallization annealing at least once or more on a hot-rolled sheet having the above-mentioned components, and a cold-rolling rate of 15% or more after final recrystallization annealing It can be manufactured by a method of manufacturing a low thermal expansion alloy sheet having a step of performing final cold rolling and a step of performing strain relief annealing at 800 ° C. or lower after the final cold rolling. Final The cold rolling rate of cold rolling was set to 15 ° or more, and the temperature for strain relief annealing was set to 800 ° C or less because of the softening annealing before pressing in Nb-added Fe-Ni alloys where recrystallization and grain growth are difficult to proceed. This is for softening without performing high-temperature annealing of 850 or more.

In summary, the flow of the method for producing a low thermal expansion alloy sheet according to the present invention is as follows: “hot rolled sheet → (cold rolling + recrystallization annealing) X n (n≥l) → final cold rolling → strain relief annealing

It becomes.

The hot rolled sheet is manufactured by melting the alloy of the above components, forming a slab by ingot making method or continuous forming method, and then heating to 900 ° C. or higher and hot rolling. In the ingot making method, the イン ingot is subjected to homogenization heat treatment at 1000 ° C or more as necessary, and then slab-rolled into a slab. Further, the slab manufactured by the continuous manufacturing method is subjected to a homogenizing heat treatment at 1000 or more, if necessary, and then hot-rolled. Hot rolling is performed, for example, at a finishing temperature of 850 950 ° C and a winding temperature of 650 800 ° C.

In addition, the hot-rolled sheet manufactured in this manner is subjected to pickling or grinding to remove the scale on the surface, and then cold-rolled and recrystallized and annealed at least once as described above to obtain a sheet thickness of 0. It is a thin plate of about 050.5. Example 1

Steel As with the components shown in Table 1 was melted in an electric furnace, ingot-formed, subjected to soaking at 1200 ° C or higher, and subjected to slab rolling to form a slab. Steel AH is an example of the present invention, and is a steel in which components such as NbVTaBSb are appropriately adjusted. Steel AB is Nb-V-added steel, Steel C is Ta-added steel, Steel D is Nb-V-Ta-added steel, Steel E is Nb-VB-added steel, Steel F is Nb-V-Sb-added steel, Steel G is Nb-VB-Sb-added steel and Steel H is Ta-B-Sb-added steel. On the other hand, steel ps is a comparative example, and steel p does not contain any Nb V Ta, steel q does not contain Nb and Ta, and steel r does not. Nb V is added to the steel, but the amount of (Nb + V) exceeds 1.0, and Nt V, is added to steel s, but (Nb + V + Ta) Is greater than 1.

Next, the slab was heated to 1000 ° C or higher after grinding the entire surface, and hot-rolled at a finishing temperature of 850 950 and a winding temperature of 650 800 ° C to obtain a hot-rolled coil. And hot rolled After pickling and removing scale from the surface, cold rolling at a cold rolling rate of 20 to 80% and recrystallization annealing at 750 to llOO are repeated twice, and the final cold rolling at a cold rolling rate of 20 to 25 is performed. Cold rolling was performed and strain relief annealing was performed at 700 to 800 ° C to produce a thin plate having a thickness of 0.12 mm.

A JIS No. 5 tensile test specimen, a ring test specimen for evaluating magnetic properties, and a test specimen for measuring thermal expansion coefficient were collected from the center of the thin-sheet coil in the width direction, and were subjected to a heat treatment equivalent to softening annealing before pressing in an Ar atmosphere. Heat treatment at 800-900 ° C for 15 minutes to evaluate the impact resistance, magnetic properties, and coefficient of thermal expansion of the shadow mask.

The tensile test was performed according to the tensile test method of JIS Z 2241, and 0.2 resistance was obtained. The magnetic properties were evaluated based on JIS C 2531, and the maximum magnetic permeability at an applied magnetic field of 10 Oe was determined.

The coefficient of thermal expansion was measured using an optical interference type thermal expansion measuring apparatus, and the average coefficient of thermal expansion at 20 to: L00 ° C was determined.

Table 2 shows the results.

FIG. 1 shows the relationship between the 0.2 proof stress after soft annealing before press and the maximum magnetic permeability. In this figure, three results are shown for the same steel, which correspond to the results of softening annealing temperatures before press of 900, 850, and 800 ° C in order from the left.

As shown in FIG. 1, in the steels A to H of the present invention, a proof stress of 0.2 to 300 to 350 MPa and a maximum magnetic permeability of 5000 or more can be obtained. Further, these steels also satisfy 0.2 PS + 7 (imax / 1000) ≥350, which is a more preferable relationship in terms of strength-magnetic property balance. From Table 2, the steel ^{A~H, 0. 8 X lO- 6} / ° C but below a low thermal expansion coefficient is obtained, especially, Mn, Nb, V, Ta or the like is low steel B~D and F At ~ H, a thermal expansion coefficient of 0.5 X 10-s Pa C or less is obtained. In addition, steels E to H to which B and Sb are added in addition to Nb, V, and Ta have higher maximum magnetic permeability.

On the other hand, the steel p with no added Nb and V, which is a comparative example, has a poor strength-magnetic property balance, and the 0.2 proof stress has not reached the target 300 MPa at any annealing temperature. In steel g containing only Nb, the strength is improved compared to steel p, but the maximum magnetic permeability is 4300 or less. Furthermore, the (Nb + V + Ta) is and steel r exceeds 1% S, 0. ^2%耐Ka is not below 350 MPa, even high thermal expansion coefficient. (mass%)

Underlined: Outside the scope of the invention

Example 2

Using the steel ingots of steels A, C and p shown in Table 1, thin plates having a thickness of 0.12 were manufactured in the same manner as in Example 1. At this time, as shown in Table 3, the cold rolling rate and the strain relief annealing temperature in the final cold rolling were changed to 5 for steel A and 3 for steel (: and p). Then, the same test was performed on this thin plate as in Example 1. The softening annealing before pressing was performed in an Ar atmosphere under the conditions of 750 to 900 × 15 minutes soaking.

Table 3 shows the results.

FIG. 2 shows the relationship between the soft annealing temperature before press and the 0.2 proof stress.

Nb and V-added steels A-1 to Α-3 are manufactured by setting the strain relief annealing temperature to 750 and changing the cold rolling rate in the final cold rolling. In each case, the 0.2% proof stress decreases significantly to 350 MPa or less as the softening annealing temperature before pressing increases. Annealing temperature 0.2 proof stress becomes 3 ² 0 MPa or less, whereas the steel A-3 in 800 ° C, the steel A-2 850 ° (:, is steel A- 1 in 900 ° C. Normally, the softening annealing before press is performed at about 800 ° C. Therefore, the steel A-3 of the present invention is a steel A-1 and a steel A-1 of a comparative example having a cold rolling reduction of less than 15 in final cold rolling. And has better softening characteristics than A-2.

Nb and V-added steels A-3 to A-5 are manufactured by changing the temperature of the strain relief annealing based on the final cold rolling rate of 25 for cold rolling. The soft anneal temperature before press at which the proof stress is 350 MPa or less is 800 ° C for steels A-3 and A-4, while it is 850 ° C for steel A-5. Therefore, steels A-3 and A-4 of the present invention have better softening properties than steel A-5 of the comparative example.

For steel Cl and p-3 with only Ta added, the strain relief annealing temperature was 750. C, and is manufactured by changing the cold rolling rate of the final cold rolling. Steels C-3 and C-5 are manufactured by changing the final cold-rolling rate to ₂₅ and changing the temperature for strain relief annealing. The annealing temperature at which the heat resistance reaches 300 to 350 MPa is 800 ° C for steel C-3, but is 850 or more for steels C-1 and C-5. Therefore, the steel C-3 of the present invention example has better softening properties than the steels C-1 and C-5 of the comparative examples.

On the other hand, ND, V, and Ta-free steels P-l, P-3, and P-5 have a strain relief annealing temperature of 800. When it is C or more, the 0.2 proof stress is less than 300 MPa, which is outside the preferable range of 300 to 350 MPa. Have been. Incidentally, the steel p-1, the P- 3, 0 at the press before anneal temperature ⁷⁵ 0 ° C. Although ² yield strength is in the goal range, the magnetic characteristics was performed to the same tests as in Example 1 When evaluated, the maximum permeability was less than 5000.

Claims

The scope of the claims

1. Real white stirrer, mass: i: 30-34% Co: 2-6%, 0: 0.02% or less, Si: 0.3% or less, Mn: 0.6 or less, P: 0.01 or less, S: 0 · 005% or less, N: 0.01 or less, A1: 0.1% or less, C; r: 0.08% or less, Ta: 0 · 01 to 1% ^ N {Nb: 0 · 05 to 1, V: 0.01 to l , Ta: 0.01 to 1%} and a low thermal expansion alloy sheet comprising at least two elements selected from the group consisting of Fe and the balance of (Nb + V + Ta) ≤1%.

2. Smooth, mass, B: 0.0005 to 0.003, Sb: 0.0015 to 0.010, contains at least one element, and parentheses (28 + 513) _: 0.001 to 0.010 1. Low thermal expansion alloy sheet.

3. a step of repeating cold rolling and recrystallization annealing on the hot-rolled sheet having the component of claim 1 or 2 at least once or more;

After the final recrystallization annealing, further performing a final cold rolling at a cold rolling reduction of 15 or more,

Performing a strain relief annealing at a temperature of 800 ° C. or less after the final cold rolling.

4. A shadow mask made of the low thermal expansion alloy sheet according to claim 1 or 2.