WO2003106720A1

WO2003106720A1 - Low-thermal expansion alloy thin sheet and its manufacturing method

Info

Publication number: WO2003106720A1
Application number: PCT/JP2003/003046
Authority: WO
Inventors: 小林　聡雄; 藤田　耕一郎; 山内　克久; 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: TW200400273A; CN1662669A; JP2004018961A; KR20040111602A

Abstract

A low-thermal expansion alloy thin sheet wherein the sheet substantially comprises 35 to 37 mass% of Ni, 0.01 to 0.07 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, and the balance of Fe, the austenite grain size number is 9 or more, the (200)-face integration is 85 mass% or less. The sheet has a sufficiently low coefficient of thermal expansion and excellent shock resistance and magnetic characteristics after it is formed into a shadow mask by softening the sheet before the press. Therefore, the sheet is preferable to a shadow mask of a cathode-ray tube.

Description

TECHNICAL FIELD The present invention relates to a Fe-Ni-based low-thermal-expansion alloy thin plate used for a cathode ray tube or the like and a method for producing the same. Etching is performed to drill the holes through which the beam passes, and softening annealing is performed before pressing to facilitate the forming. Press-forming is performed according to the shape of the CRT, and then assembled into the CRT.

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, resulting in deformation of the shadow mask due to thermal expansion and electron beam passing through the holes in the shadow mask. In fact, the present inventors have found that the average thermal expansion coefficient of the Fe—Ni-based alloy thin plate at 20 to L00 ° C. is 1.2. X10. If C or less, doming hardly occurs, if further ^{0. 9 X lO- 6 / °} C or less, it was confirmed that no happening command and Ho is doming.

On the other hand, Fe-Ni alloy thin plates have a color due to dents in the shadow mask surface caused by shocks such as vibration when transporting a cathode ray tube, and electron beam deflection caused by insufficient magnetic shielding. There is a problem of misalignment, and there is a strong demand for improved impact resistance and improved magnetic properties after annealing before soft pressing.

The present inventor has studied impact resistance and magnetic properties after soft annealing before press beforehand. However, if the proof stress after softening and annealing before press is 270 MPa or more, the dent generation rate in the impact test after shadow mask forming is significantly reduced, and if the proof stress after 0.2 exceeds 320 MPa, the shadow mask It was found that press forming itself became difficult. When the maximum magnetic permeability was 7000 or more, it was found that the penetration magnetic flux was remarkably reduced in the magnetic shielding test after etching.

In order to improve impact resistance (improvement of strength), Japanese Patent No. 3150831 proposes a low thermal expansion alloy sheet in which Nb is added to an Fe-Ni alloy to improve Young's modulus. Specifically, white 3 contains C: 0.003 to 0.02%, N: 0.01% or less, Si: 0.01 to 2.0, Mn: 0.01 to 3.0%, Ni: 25 to 45¾, Cir: 1.0¾ or less, Nb: 0.01 to 1.0% , B: 0.01% or less, S: 0.01% or less, the balance being Fe and unavoidable impurities, and (C + N) ≤-0.008Nb + 0.023.

On the other hand, in order to improve magnetic properties, Japanese Patent Application Laid-Open No. Hei 10-199719 proposes a Fe-Ni-based alloy sheet in which N is reduced and B is added. The details are as follows: 30-85 Ni Fe-Ni-based alloy added so that N is 50 ppm or less and B is in the range of 5-50 ppm so that B [at.ru] / N [at.] Becomes 0.8 or more. It is a thin plate. In this alloy sheet, excellent magnetic properties can be obtained by setting A1 to 400 ppm or less and 0 to 50 ppm or less, and it is stated that the addition of Cr, Mo, Cu, Si, etc. is effective in improving the magnetic properties. . However, in the alloy thin plate described in Japanese Patent No. 3150831, although the rigidity of the shadow mask is improved by the high Young's modulus, a high magnetic permeability cannot be obtained stably, and the magnetic shielding properties of the shadow mask are insufficient. is there. The thermal expansion coefficient is 1.51～2.32X10- ⁶ Pas C, it can not be sufficiently suppressed doming.

The alloy sheet described in Japanese Patent Application Laid-Open No. 10-199719 has a wide Ni component range, and does not stably provide a desired low thermal expansion coefficient. DISCLOSURE OF THE INVENTION '' The present invention provides a sufficiently low coefficient of thermal expansion, It is an object of the present invention to provide a Fe-Ni-based low thermal expansion alloy sheet which can obtain excellent impact resistance and magnetic properties after mask molding, and a method for producing the same. This purpose is, in mass%, Ni: 35-37, C: 0.01-0.07, Si: 0.3 or less, Mn: 0.6% or less, P: 0.01 or less, S: 0.005¾ or less,: 0.01 The following can be achieved by a low-thermal-expansion alloy sheet consisting of 0.1% or less of Al and the balance of Fe and having an austenite grain size number of 9 or more and a (200) plane integration degree of 85 or less. This low-thermal-expansion alloy sheet has a step of repeating cold rolling and recrystallization annealing at least once on a hot-rolled sheet having the above components, and a step of further performing final cold rolling after the final recrystallization annealing. In addition, the present invention can be realized by a method for producing a low thermal expansion alloy sheet in which the cold rolling rate of cold rolling immediately before the final recrystallization annealing is 50 to 90 and the temperature of the final recrystallization annealing is 1000 ° C or less. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a diagram showing the relationship between 0.2耐Ka after pressing before anneal (0. ² PS) and maximum magnetic permeability (max). MODES FOR CARRYING OUT THE INVENTION The present inventors studied the impact resistance and magnetic properties of Fe-Ni-based alloy sheets after soft annealing before pressing, and the etching properties. As a result, the impact resistance and magnetic properties can be improved by controlling the C content to a specific range larger than that of ordinary Fe-Ni alloy thin sheets. It was clarified that softening before press depends more on 0.2 proof stress after annealing. The details are described below.

1. Ingredients Ni: Ni is an essential element for obtaining low thermal expansion. If it is less than 35 or more than 37, the coefficient of thermal expansion will not be sufficiently low, so Ni should be 35 to 37.

C: C must be at least 0.01% in order to improve the impact resistance and magnetic properties after soft annealing before pressing. However, if it exceeds 0.07, the etching characteristics and the low thermal expansion properties are deteriorated, so the C content is set to 0.01 to 0.07.

Si: Si has a low thermal expansion property and degrades the black mask processing property of the shadow mask. Therefore, the content of Si is set to 0.3% or less, preferably 0.09 or less.

Μη: Μη is set to 0.6 or less, preferably 0.1 or less in order to deteriorate the low thermal expansion property. Since η is an element effective for deoxidation and hot workability of the alloy, η is preferably 0.01 or more.

Ρ: Ρ is 0.01 or less in order to degrade etching characteristics.

S: Since S precipitates as sulfide and deteriorates the hot workability of the alloy, S is set to 0.005 or less.

Ν: When Ν is contained together with elements such as Al, Nb, V, etc., it precipitates as nitrides, deteriorating the etching characteristics and deteriorating the hot workability of the alloy. Below.

A1: Since A1 precipitates as nitride and deteriorates low thermal expansion property and also deteriorates hot workability of the alloy, it is set to 0.1 or less, preferably 0.04 or less. A1 also has the effect of reducing inclusions in the alloy at the time of smelting, and is therefore preferably 0.005 or more.

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

Thus, substantially, by mass, Ni: 35 to 37%, C: 0.01 to 0.07%, Si: 0.3 or less, n: 0.6 or less, P: 0.01% or less, S: 0.005% ¾TΝ: 0.01 Hereinafter, by setting the Al content to 0.1% or less and the balance to Fe, a thermal expansion coefficient of 1.2 X 10-6 / ° C or less, in which doming does not easily occur, can be obtained. Furthermore, Si: 0.09 or less, Mn: 0.01~ 0.1, A1: With from 0.005 to 0.04%, or less of the thermal expansion coefficient 0.9 X 10- ⁶ / ° C which is de one timing hardly obtained. 2. Austenite grain size

As described above, in the present invention, since the amount of C is higher than that of the conventional alloy for shadow masks, fine carbides precipitate and roughen the wall surfaces of the etching holes, which hinders high definition and high brightness of the shadow mask. Invite. However, if the austenite grain size number measured in the section along the rolling direction according to JIS G0551 is 9 or more (fine grain refinement), the wall surface of the etching hole can be prevented from being roughened.

3. (200) surface integration

The roughness of the wall surface of the etching hole is affected not only by the fine carbides described above but also by the degree of (200) plane integration. When the degree of (200) plane integration exceeds 85, the roughness becomes remarkable. Were it connexion, it is necessary to or less ⁽² 00) plane integration is 8 ^5.

Here, the degree of integration of the (200) plane was determined by X-ray diffraction using MoKQ! Rays, and the austenite 7 plane (111), (200), (220), (311), (331), (420), (420) 422) was measured, and the intensity of each surface was divided by the theoretical integrated intensity of a sample in a random orientation to obtain the following formula (1).

Degree of integration of (200) plane = {1 (200) / D (200)} B {i (hkl) / I (hkl)} Xl00

(1) i (hkl): Measured integrated intensity of (hkl) plane in measured sample

I (hkl): The theoretical integrated intensity of the (hkl) plane in a sample with random orientation

和: Sum of 7 faces

4. 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 components, and a step of further performing final cold rolling after final recrystallization annealing. And the cold rolling ratio of cold rolling immediately before the final recrystallization annealing is 50 to 90, and the temperature of the final recrystallization annealing is 1000 ° C or less. Can be manufactured. The reason why the cold rolling rate in the final cold rolling is set to 50 to 90 is that if the cold rolling ratio is less than 50, the austenite grain size number is less than ⁹ (coarsening), and if it exceeds 90, the (200) plane integration is This is to exceed 85. The reason why the temperature of the final recrystallization annealing was set to 1000 ° C or less is that when the temperature exceeds 1000 ° C, the austenite grain size number is less than 9. This is because

In summary, the flow of the method for producing a low thermal expansion alloy sheet according to the present invention is “hot rolled sheet → (cold rolling + recrystallization annealing) X n (n≥l) → final cold rolling”. However, if necessary, recovery annealing can be performed after the final cold rolling.

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. The slab manufactured by the continuous production method is subjected to a homogenizing heat treatment at 1000 ° C or more, if necessary, and then hot-rolled. The hot rolling is performed, for example, at a finishing temperature of 850 to 950 ° C and a winding temperature of 65O to 80 ° 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 05-0.5mm. Example 1

Steels A to F having the components shown in Table 1 were smelted in an electric furnace, ingot-ingoted, soaked at 1200 ° C or higher, and slab-rolled into slabs. Steels A to D are examples of the present invention, and steels E and F are comparative examples. '

Next, after grinding the entire surface of the slab, the slab was heated to 1000 ° C or higher, and hot rolled at a finishing temperature of 850 to 950 ° C and a winding temperature of 650 to 800 ° C to obtain a hot rolled coil. Then, the hot-rolled coil is pickled to remove the surface scale, then cold-rolled at a cold-rolling rate of 20 to 80%, and re-annealed at 750 to L100 ° C. After cold re-rolling at 1000 ° C and repeated recrystallization annealing, the final cold rolling was performed at a cold rolling reduction of 15 to 40 ° C, and recovery annealing was performed at 700 to 800, and the sheet thickness was reduced to 0. 12 thin plates were made. In this example, before the final cold rolling, cold rolling and recrystallization annealing were repeated twice.

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. 750-900 seconds for 15 minutes soak and heat treatment, shadow mask Impact resistance, magnetic properties, and coefficient of thermal expansion were evaluated.

The tensile test was performed in accordance with the bow I tension test method of JIS Z 2241, and 0.2 heat resistance was determined. The magnetic properties were evaluated based on JIS C 2531, and the maximum magnetic permeability at an applied magnetic field of 100 e was obtained.

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.

In addition, a test piece for evaluating the etching characteristics was taken from the center in the width direction of the thin-plate coil, and the wall surface of the etching hole after the photoetching was observed by SEM, and evaluated by the following Δ, Δ ·, and X. Note that 〇 and 厶 are not practically a problem.

〇: No unevenness

Δ: slightly uneven

X: With irregularities

Table 2 shows the results.

Fig. 1 shows the relationship between 0.2 proof stress after soft annealing and pre-pressing and the maximum magnetic permeability. In this figure, four results are shown for the same steel, which correspond to the results of softening annealing temperatures before press of 900, 850, 800, and 750 ° C from left to right.

According to FIG. 1, in the steels A to D of the present invention, a 0.2 yield strength of 270 to 320 MPa and a maximum magnetic permeability of 7000 or more can be obtained. Furthermore, these steels also satisfy 0.2 PS + 6 (max / 1000) ≥340, which is a more preferable relationship from the viewpoint of strength-magnetic property balance. From Table 2, the steel A~D an invention example, 1.2X10- ⁶ but Pas C following a low thermal expansion coefficient is obtained, in particular, the amount of Mn is lower steel D, 0.9XlO- ⁶ / ° C or less Is obtained.

On the other hand, in the case of steel E, which is a comparative example, in which the C content is lower than the range of the present invention, the strength-magnetic property balance is poor, and a 0.2 yield strength of 270 to 320 MPa and a maximum magnetic permeability of 7000 or more cannot be obtained at the same time. Further, in steel F having a C content higher than the range of the present invention, there is no problem in strength-magnetic property balance or thermal expansion coefficient, but the etching property is inferior. table 1

(mass%)

Underlined: Outside the scope of the invention

Underline: Out of target range Example 2

Using the steel A ingot shown in Table 1, a thin plate having a thickness of 0.12 nim was produced in the same manner as in Example 1. At this time, as shown in Table 3, the cold rolling ratio of the cold rolling immediately before the final recrystallization annealing and the final recrystallization annealing temperature were changed in seven ways. Then, the austenitic crystal grain size number, the degree of (200) plane integration, and the etching characteristics of this thin plate were measured.

Table 3 shows the results.

Steels 1 to 4 are manufactured by setting the final recrystallization annealing temperature to 950 ° C and changing the cold rolling rate of the cold rolling just before the final recrystallization annealing.

Steels 2 and 3 with proper cold rolling reduction yield excellent etching characteristics.

On the other hand, Steel 1 having a cold rolling reduction lower than the range of the present invention has a small crystal grain size number (large crystal grains) and poor etching characteristics. Steel 4 having a higher cold rolling ratio than the range of the present invention has a high degree of (200) plane integration and is inferior in etching characteristics.

Steels 5 to 7 are manufactured by changing the cold rolling rate of the cold rolling just before the final recrystallization annealing to 85 and changing the final recrystallization annealing temperature.

Steels 5 and 6, whose final recrystallization annealing temperature is 1000 ° C or less, show excellent etching characteristics.

On the other hand, steel 7 having a final recrystallization annealing temperature higher than the range of the present invention has a small grain size number and is inferior in etching characteristics.

From the above, it can be seen that in order to obtain excellent etching characteristics, the austenite grain size number should be 9 or more and the (200) plane integration degree should be 85 or less.

Final cold rolling Final recrystallization sintering Date (200) plane Cold rolling rate of etching (%) Preliminary temperature (.c) 去 Removal density (%)

30 950 24 X Comparative example

50 950 9 37 例 Invention example

90 950 10 85 例 Invention example

95 950 10.5 92 X Comparative example

85 850 10 59 m Invention example

85 1000 9.5 64 例 Invention example

85 1 100 68 X Comparative example Underlined part: out of range of invention

Claims

The scope of the claims

1. Effectively, by mass, Ni: 35-37, C: 0.01-0.07, 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: Low thermal expansion alloy sheet composed of 0.1 or less and the balance of Fe and having an austenite grain size number of 9 or more and a (200) plane integration degree of 85 or less.

2. The low thermal expansion alloy sheet according to claim 1, wherein Si: 0.09% or less, Mn: 0.01 to 0.1S, and A1: 0.005 to 0.04%.

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

After the final recrystallization annealing, further performing a final cold rolling,

A method for producing a low-thermal-expansion alloy sheet, wherein a cold-rolling rate of cold rolling immediately before the final recrystallization annealing is 50 to 90, and a temperature of the final recrystallization annealing is 1000 ° C or less.