WO2004076703A1

WO2004076703A1 - Steel sheet for recording medium case, method for producing same and recording medium case

Info

Publication number: WO2004076703A1
Application number: PCT/JP2004/001703
Authority: WO
Inventors: Toshiyuki Ueda; Hiroyasu Itoh; Satoshi Ohi; Shinichi Aoki
Original assignee: Toyo Kohan Co., Ltd.
Priority date: 2003-02-28
Filing date: 2004-02-17
Publication date: 2004-09-10
Also published as: TW200418995A; TWI240006B; JP2004263225A

Abstract

A steel sheet for recording medium cases used for protecting recording mediums such as a CD-ROM, CD-R, CD-RW, and MO is disclosed. A method for producing such a steel sheet and a recording medium case are also disclosed. The steel sheet for recording medium cases is characterized by having a chemical composition including, in weight %, C: 0.08-0.60%, Si: 1.0-3.0%, Mn: 0.5-3.0%, P: ≤ 0.06%, S: ≤ 0.06%, Al: ≤ 0.1%, N: 0.0010-0.0150%, and the balance: Fe and unavoidable impurities.

Description

Description Steel plate for recording medium casing, manufacturing method thereof, and recording medium casing

The present invention relates to a steel plate for a housing of a recording medium used for protecting a recording medium such as a CD-ROM, a CD-R, a CD-RW, and a MO, a method of manufacturing a steel plate for a housing of a recording medium, and recording. The present invention relates to a medium housing. BACKGROUND ART Generally, a stainless steel plate having excellent mechanical strength and corrosion resistance is used as a material of a housing used to protect recording media such as CD-ROM, CD-R, CD-RW, and MO. Have been.

As a case using such a stainless steel plate for a casing of a recording medium, for example, Japanese Patent Application Laid-Open No. 2002_50149 is disclosed. However, since stainless steel plates are expensive, there is a problem in terms of economy.

As described above, when a stainless steel plate is used as the material of the casing of the recording medium, there is a problem that the cost is increased. In addition, when inexpensive steel plates were applied, there was a problem in that the mechanical properties were poor, so they could not be applied.

The present invention has been made in view of these points, and an object of the present invention is to provide a steel plate for a casing of a recording medium which is inexpensive and has excellent mechanical properties, a method for manufacturing the same, and a casing for the recording medium. I do.

As its mechanical properties, the tensile strength (tensile strength: hereinafter, TS) of JIS No. 5 piece must be 50 OMPa or more, and the elongation of 15% or more (total elongation: hereafter, T.

E) is required. Disclosure of the invention

In order to achieve the above object, the present inventors have conducted intensive studies. As a result, by weight%, C: 0.08 to 0.60%, Si: 1.0 to 3.0% Mn: 0.5 to 3 0%, P: ≤ 0.06%, S≤ 0.06%, A1: ≤ 0.1%, N: 0.0010-0.0150%, balance Fe and inevitable impurities The present inventors have found that a steel sheet made of such a material is excellent as a material for a casing of a recording medium, and have completed the present invention.

The steel sheet for a casing of a recording medium according to claim 1 is, in terms of% by weight, C: 0.08 to 0.60%, Si: 1.0 to 3.0%, and Mn: 0.5 to 3.0. %, P: ≤ 0.06%, S: ≤ 0.06%, A1: ≤ 0.1%, N: 0.0010 ~ 0.0150%, balance Fe and inevitable impurities Features.

This makes it possible to obtain an inexpensive steel sheet for a housing of a recording medium having excellent mechanical properties.

The method for producing a steel sheet for a housing of a recording medium according to claim 2 is as follows: C: 0.08 to 0.60%, Si: 1.0 to 3.0%, Mn: 0.5% by weight. ~ 3.0%, P: ≤ 0.06%, S: ≤ 0.06%, A1: ≤ 0.1%, N: 0.0010 ~ 0.0150

%, The remainder of Fe and unavoidable impurities, hot-rolled, pickled, then cold-rolled at a reduction ratio of 50 to 90%, and then continuously annealed. Anneal at 630 to 870 ° C or 500 to 750 ° C by batch annealing, then perform secondary rolling at a rolling reduction of 7% or less, and further apply Zn or Ni plating to the surface. .

This makes it possible to manufacture a steel plate for a housing of a recording medium that is inexpensive and has excellent mechanical properties.

The casing of the recording medium may be a steel sheet for a casing of a recording medium according to claim 1 or a steel sheet for a casing of a recording medium manufactured by the method for producing a steel sheet for a casing of a recording medium according to claim 2. It is characterized in that it was created using

This makes it possible to obtain an inexpensive recording medium housing with excellent mechanical properties. it can. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing an embodiment of the housing of the recording medium of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. The housing of the recording medium of the present invention is formed, for example, as shown in FIG. The housing 1 of the recording medium in FIG. 1 is formed for a CD-ROM, and is formed in a thin box shape so as to accommodate the CD-ROM 3 therein by using a steel plate 2 for the housing of the recording medium. Being manufactured. The overall shape of the housing 1 of the recording medium is a general one, and one of the two side parts 4, 4 has access to a driving means for rotating the CD-ROM 3 and a reading means (both not shown). A notch portion 5 is formed to allow a necessary shirt (not shown) and the like to be provided.

Next, the steel sheet for the housing of the recording medium will be described.

The composition of the steel sheet for the housing of the recording medium of the present invention is, by weight%, C: 0.08 to 0.60. S i: 1.0 to 3.0%, Mn: 0.5 to 3.0%, P: ≤ 0.06%, S: ≤ 0.06% A1: ≤ 0.1%, N: 0.0010 to 0.0150%, balance

It is formed by Fe and unavoidable impurities.

C is desirably present in an amount of 0.08% by weight or more in order to add a high degree of tempering to the steel sheet for the housing of the recording medium. On the other hand, when the content exceeds 0.60% by weight, the amount of carbide precipitation increases, resulting in a reduction in the workability of the steel sheet for the recording medium housing, and at the same time, an increase in the load of the cold rolling, deterioration of the shape, and an increase in the continuous annealing process. It may cause a decrease in productivity such as inhibition of plate properties. Therefore, in the present invention, the upper limit of the component C is set to 0 to 60% by weight.

Mn is a component necessary to prevent red-hot brittleness during hot rolling due to S, which is an impurity, and at the same time, imparts a high degree of tempering to the steel sheet for the housing of the recording medium as in C above. Therefore, the Mn component should be 0.5% by weight or more. Again, as in C, too much causes an increase in cold rolling load, cracks during slab rolling, shape deterioration, and impaired productivity in the continuous annealing process, etc. Therefore, the upper limit is set to 3.0% by weight

P is a component for refining crystal grains, and is added at a certain ratio to increase the strength of a steel sheet for a housing of a recording medium, but impairs corrosion resistance. For the purpose of the present invention, if P exceeds 0.06% by weight, the corrosion resistance, particularly the pitting resistance, is significantly reduced, so the upper limit is set to 0.06% by weight.

S is an impurity component that causes red-hot embrittlement during hot rolling, and it is desirable that it be as small as possible.However, it cannot be completely prevented from being mixed in with iron ore, etc., and desulfurization during the process is difficult. Unavoidable. Since red hot embrittlement due to a small amount of residual S can be reduced by Mn, the upper limit of the S component is 0.06 weight. / ₀ .

A1 is added to the steel bath as a deoxidizing agent in steelmaking, but when it becomes 0.10% by weight or more, it is used as an antioxidant during continuous production and as an anti-seizure agent for molds in continuous production. The excess A1 reacts with the oxygen in the 鎵 type powder to inhibit the original powder effect. Therefore, the amount of A1 should be 0.10% by weight or less.

N, like C and Mn, gives a high degree of tempering to the steel sheet for the housing of the recording medium. Although it is a necessary component for strengthening the steel, if it is less than 0.001% by weight, it will be difficult to make steel. The yield is remarkably reduced and the stability is lacking. At the same time, the anisotropy during press molding is significantly deteriorated. Further, since cracks occur on the surface of the continuous structure and cause structure defects, in the present invention, the range of the N component is set to 0.001 to 0.0150% by weight. More preferably, the content is 0.0021 to 0.0150% by weight.

Si is a key feature of the present invention. Si has a large solid solution strengthening ability in steel and is an effective element for obtaining spring properties. Therefore, 1.0% by weight or more is necessary. In addition, the more the material is strengthened, the better. The upper limit is set to 3.0% by weight to increase the shape and deteriorate the shape.

Next, a method for manufacturing the steel sheet for a housing of a recording medium according to the present invention will be described.

Hot rolling

The slab heating temperature in the hot rolling step is not specified in the present invention, but is preferably 1100 ° C or more from the viewpoint of active decomposition of N and stable securing of the hot finish rolling temperature. . If the hot rolling finishing temperature is lower than Ar 3 points, the crystal structure of the hot steel strip is mixed and coarsened, and the desired strength cannot be obtained.Therefore, the hot rolling finishing temperature is higher than Ar 3 points. It is desirable to do.

Winding temperature shall be 450 ° C ~ 650 ° C. The lower limit is 450 ° C in consideration of the quality stability of the coil in the width and length directions during hot rolling. If the winding temperature exceeds 650 ° C, the crystal grain size increases during hot rolling and continuous annealing, which may cause defects when processing into a recording medium housing. It is desirable to do the following.

The force of cold rolling after pickling a steel sheet hot-rolled with the above-mentioned component system. This cold rolling ratio is an important strength factor of the present invention together with the components, and is 50 to 90 to obtain the desired strength. Perform in%.

The material that has been cold-rolled by 50 to 90% as described above is degreased in the cleaning process, and then subjected to continuous annealing at 630 to 870 ° C, preferably 680 to 870 ° C. . Alternatively, perform batch annealing at 500 to 750 ° C, preferably 600 to 750 ° C. The annealing time may be within the range of recrystallization.

After annealing, secondary rolling or temper rolling at a rolling reduction of 7% or less is performed. Then, if necessary, surface roughness is imparted by temper rolling. The thickness of the sheet is not particularly limited, but is preferably in the range of 0.2 :! to 0.5 mm, more preferably 0.2 to 0.35 mm.

Next, the sheet steel for a housing of the recording medium of the present invention prepared in this way includes sheet-like and coil-like steel sheets, steel foils, and those obtained by subjecting these steel sheets to surface treatment. Is raised. In particular, nickel plating, zinc plating, zinc-cobalt-molybdenum composite plating, zinc-nickel alloy plating, zinc-iron alloy plating, hot-dip zinc plating, hot-dip zinc-aluminum alloy plating and their plating Those that have undergone chemical conversion are excellent in terms of corrosion resistance. As the chemical conversion treatment, known treatments can be applied, and for example, a mouth mate treatment, a phosphate treatment, an electrolytic vanadium treatment, a silicate treatment or a lithium silicate treatment can be applied. Example

Table 1 shows the steel composition and the production conditions such as the rolling reduction, and Table 2 shows the characteristics evaluation results of the examples and comparative examples of the present invention. In Table 1, those without secondary rolling had a surface roughness (JISB 0102, Ra) of 0.8 πι by temper rolling. Sample numbers 1 to 4 and 7 to 12 contain 0.5 mm zinc with a thickness of 0.3 mm. / ₀ Cobalt-0.01% by weight molybdenum composite plating (zinc plating amount: 15 g Zm ² ), followed by chromate treatment so that the adhesion amount as Cr becomes 38 mg Zm ² . Sample Nos. 5 to 6 and 13 to 16 contain a 0.2 mm thick zinc-0.5% by weight cobalt-0.01% by weight molybdenum composite plating (zinc plating amount: 10 g / m ² ). After the application, electrolytic vanadium treatment was performed so that the amount of adhesion as V became 7 Omg / m ² .

In Table 2, samples with a pile tension (TS) of 50 OMPa or more and an elongation (T.E.) of 15% or more were determined to be good.

From Table 1 and Table 2, the samples Nos. 1 to 6 of the examples are excellent in tensile strength and elongation, and can be used for a casing of a recording medium.

On the other hand, Sample Nos. 7 to 8 and 12 have low tensile strength and thus lack strength. Sample Nos. 9 to 11 and 13 to 16 have low elongation and poor workability. Sample No. Example or chemical composition (% by weight) Primary rolling Continuous annealing patch Secondary rolling Comparative example C Si Mn P Al N (rolling rate, ¾);

Dish annealing (8h) (Rolling rate,%)

1 Example 1 0.09 1.5 2.5 0.030 0.031 0.0050 70% 820 ° C 5%

2 Example 2 0.15 2.8 1.7 0.010 0.062 0.0032 70% 820 ° C 3%

3 Example 3 0.13 2.0 2.1 0.021 0.044 0.0028 70% 820 ° C 7%

4 Example 4 0.09 1.5 2.5 0.030 0.031 0.0050 70% 720 ° C None

5 Performed row 5 0.15 2.8 1.7 0.010 0.062 0.0032 70% 720 ° C None

6 Perform 1 row 6 0.13 2.0 2.1 0.021 0.044 0.0028 70% 670 ° C None

7 Comparison 1 row 1 0.04 1.5 1.7 0.011 0.061 0.0029 70% 720 ° C None

8 Comparison 1 2 0.15 0.8 1.8 0.021 0.049 0.0054 70% 720 ° C None

9 Comparison 1 row 3 0.72 1.8 1.7 0.008 0.022 0.0033 70% 720 ° C None

10 Comparison 1 row 4 0.16 3.2 1.2 0.014 0.012 0.0011 70% 720 ° C None

11 Comparative Example 5 0.28 1.1 3.3 0.015 0.007 0.0024 70% 720 ° C None

12 Comparative Example 6 0.22 2.1 0.3 0.020 0.082 0.0110 70% 720 ° C None

13 Comparative Example 7 0.09 1.5 2.5 0.030 0.032 0.0050 70% 600 ° C 65%

14 Comparative Example 8 0.13 2.0 2.1 0.021 0.044 0.0028 70% 490 ° C None

15 Comparative Example 9 0.15 0.8 1.8 0.021 0.049 0.0054 70% 800 ° C 15%

16 Comparative Example 10 0.72 1.8 1.7 0.008 0.022 0.0033 70% 800 ° C 50%

Evaluation of mechanical properties

The mechanical properties of tensile strength and elongation were measured by processing a sample into a JIS No. 5 test piece and using a tensile tester. A sample having a tensile strength (TS) of 500 MPa or more and an elongation (Τ · EL) of 15% or more was evaluated as good. Table 2 Characteristic evaluation results

Industrial applicability

As described above, the steel sheet for a housing of a recording medium, the method of manufacturing the same, and the housing of the recording medium of the present invention are inexpensive and have excellent mechanical properties. Specifically, the composition of the material used for the steel sheet for the housing of the recording medium of the present invention is ⁰ / o in weight, C: 0.08 to 0.60%, S i: 1 • 0 to 3.0%, Mn: 0.5 to 3.0%, P: ≤0.06%, S: ≤0.06% _s A1: ≤0.1%, N: 0.0010 to 0.0150%, balance Fe And unavoidable impurities, as shown in Tables 1 and 2, It exhibits excellent mechanical properties (tensile strength and elongation) and can be used as a housing for recording media used to protect recording media such as CD_ROM, CD-R, CD-RW and MO. Also, since it is cheaper than conventional stainless steel, it is suitable as an economical recording medium housing.

Claims

The scope of the claims

1. By weight%, C: 0.08 to 0.60%, S i: 1.0 to 3.0%, M n: 0.5 to 3.0% P: ≤ 0.06%, S: ≤ 0.06%, A1: ≤ 0.1%, N: 0.0010 to 0.015%, the balance Fe and unavoidable impurities.

2. By weight%, C: 0.08 to 0.60%, Si: 1.0 to 3.0%, Mn: 0.5 to 3.0%, P: ≤ 0.06%, S: ≤ 0.06%, A1: ≤ 0.1%, N: 0.0010 to 0.0 Γ50%, after continuous rolling of a continuous structure consisting of Fe and unavoidable impurities, after hot rolling Pickling, then cold rolling at a rolling rate of 50 to 90%, then annealing at 630 to 870 ° C in continuous annealing or 500 to 750 ° C in batch annealing, and then rolling rate 7 % Or less, and further subjected to Zn or Ni plating on the surface.

3. A casing for a recording medium, which is made using the steel sheet for a casing of a recording medium according to claim 1.

4. A casing for a recording medium, which is produced by using the casing steel sheet for a recording medium manufactured by the method for producing a casing steel sheet for a recording medium according to claim 2.