JP3449126B2 - Austenitic stainless cold-rolled steel sheet with small springback amount and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an austenitic stainless cold-rolled steel sheet having a small springback amount after bending, overhanging, etc., and a method for producing the same.

[0002]

2. Description of the Related Art Stainless steel sheets are widely used after being processed into bathtubs, pots, dishes, sinks, etc. because of their excellent corrosion resistance and workability. Among them, austenitic stainless steel sheets are widely used because they are excellent in bending and overhanging workability and can be press-formed even in a complicated shape. However, the austenitic stainless steel sheet has a problem that the amount of springback after forming is large because the work hardening is large and the strength after press forming is high. Therefore, when press-molding an austenitic stainless steel sheet, the mold is usually designed in consideration of the springback amount in advance. But,
In such a method, it is necessary to investigate the characteristics of the steel sheet to be used before designing the die, and there is a problem that the usable steel sheet is limited once the die is designed. It was

By the way, it is widely known that in order to reduce the amount of springback during press molding, it is effective to lower the yield strength, that is, increase the n value if the strength is constant. Therefore, as a method for producing an austenitic stainless steel sheet, the temperature of finish annealing (cold rolled sheet annealing) is increased (for example, 1150 ° C or higher),
It is known to increase the crystal grain size (for example, the grain size number is 5 or less).

[0004]

However, in such a method for increasing the crystal grain size, roughening of the surface called orange peel after press working or deep oxidation-induced groove deepening due to high annealing temperature is caused. Due to the grain boundary erosion, new problems such as deterioration of corrosion resistance and surface appearance were caused. As a technique related to the amount of spring back during press forming, Japanese Patent Laid-Open No. 7-197199 and Japanese Patent Laid-Open No. 7-197200 disclose a shape freezing amount of austenitic stainless steel during hole expanding and deep drawing. Techniques for reducing the anisotropy by adjusting the amounts of C, N, Ni, and Mn have been disclosed, but in these methods, the anisotropy of the springback amount after press molding is small, but the springback amount is small. It cannot be made smaller.

Therefore, an object of the present invention is to provide an austenitic stainless cold-rolled steel sheet having a small springback amount after press forming such as bending and drawing without increasing the crystal grain size, and a method for producing the same. It is in. Another object of the present invention is to produce austenitic stainless steel with fine grains having a grain size number of 6 or more and a small springback amount after press molding even if the P amount is in a relatively high range of 0.04 wt% or less. It is to provide a rolled steel sheet and a method for manufacturing the same.

[0006]

As described above, in order to reduce the amount of spring back during press forming, it is effective to lower the yield strength, in other words, increase the n value if the strength is constant. is there. Also, Nagashima Fu-Author:
As described on pages 281-283 of “Texture” (1984, Maruzen), in Cu alloys, the yield strength changes depending on the texture of the alloy, and the yield strength when crystal grains are pulled in the <100> direction. It is said to be lower than when pulled in the other direction.

Based on the above, the inventors have found that if the {200} texture can be developed on the plane parallel to the rolled surface (plate surface) of the cold rolled austenitic stainless steel, the crystal grain size is fine. It was thought that the yield strength could be lowered and the n value could be increased even as it was. The inventors
In the process of searching conditions for producing a cold-rolled steel sheet having a high degree of accumulation of {00} texture, the {111} texture of the surface parallel to the rolling surface of the material before cold rolling (that is, hot-rolled sheet) The higher the degree of accumulation, the higher the degree of accumulation of {200} texture in the plane parallel to the rolled surface of the steel sheet after cold rolling and finish annealing. The tendency is that the amount of P is 0.015 wt.
It was found that it becomes remarkable when it is reduced to less than%.
However, in this case, there is a problem that the cost of raw materials and smelting increases because it is necessary to reduce the amount of P to 0.015 wt% or less.

Therefore, the inventors of the present invention economically economically integrate the {200} aggregate fine weave on the plane parallel to the rolled surface after cold rolling and finish annealing without reducing the P content to 0.015 wt% or less. Further research was conducted on the manufacturing technology for increasing the value. As a result, as shown in the example of SUS304 in FIG. 1, even if the P content is a relatively high content of 0.04 wt% or less, it is parallel to the rolled surface of the material (hot rolled sheet) before cold rolling. If the degree of accumulation of the {111} texture in the plane is 2.2 or more, the degree of accumulation of the {200} texture in the plane parallel to the rolled surface after cold rolling and finish annealing can be 1.5 or more. I found it possible.

In order to increase the degree of accumulation of {111} texture in the plane parallel to the rolling surface of the hot rolled sheet to 2.2 or more, the equiaxed crystal ratio of the continuous cast slab and the final finish in the hot finish rolling are used. It was found that this can be achieved by optimizing the pass temperature and reduction rate. That is, in FIG.
For SUS304 with an amount of 0.04 wt%, the finishing temperature of the final pass of hot rolling is 1050 ° C, and the strain rate is 150 / s.
ec shows the effect of the equiaxed crystal ratio of the slab on the degree of accumulation of {111} texture in the plane parallel to the rolled surface of the hot-rolled sheet when the rolling reduction is 15%. From this, the equiaxed crystal ratio is much higher than the conventional level (≈0%).
It can be seen that the content of {111} texture in the plane parallel to the rolled surface of the hot-rolled sheet is 2.2 or more when the content is at least%. FIG. 3 shows that for SUS304 having a P content of 0.04 wt% and a slab equiaxed crystal ratio of 30%, the effect of hot rolling on the accumulation degree of {111} texture in the plane parallel to the rolling surface of the hot rolled sheet. This shows the influence of the final pass condition. From this, by setting the temperature of the final pass of hot rolling to 1050 ° C. or more and the rolling reduction to 15% or more, the degree of accumulation of {111} texture on the plane parallel to the rolling surface of the hot rolled sheet becomes 2.2 or more. You can see.

The mechanism showing such a tendency is not always clear, but the inventors consider it as follows. First, the higher the degree of accumulation of the {111} texture before cold rolling, the higher the degree of accumulation of the {200} texture after cold rolling and annealing is that the {111} texture develops before cold rolling. , The {111} texture can be deformed while maintaining the relatively same surface even after rolling, so even after cold rolling {111}
Between the development of texture and between the recrystallized grains and the deformed grains, as described in the metallographical introduction (1968, 262), 22 de with respect to the <111> axis.
There is a relationship of g and 38 deg, which is considered to be related to the fact that recrystallized grains having {200} texture are relatively easily generated from deformed crystal grains having {111} texture. Moreover, the equiaxed crystal ratio of the slab is high, the hot rolling temperature is high,
When the rolling reduction is large, the {111} texture develops in the plane parallel to the rolled surface after hot rolling. Under these conditions, the texture of any orientation is during or immediately after hot rolling. Since the recovery and recrystallization occur in the alloy, the strain is concentrated in a specific direction, preferential recrystallization does not occur, and the {111} texture, which is difficult to store the strain, is not eroded. We believe that the {111} texture created by rotation will develop.

FIG. 4 shows SUS30 having a P content of 0.04 wt%.
No. 4, the equilibrium crystal ratio of the slab and the hot rolling conditions were changed to change the degree of accumulation of {200} texture in the plane parallel to the rolled surface. N values parallel to, at right angles to, and at 45 degrees (
1, nd, nc) and the amount of springback (S, respectively)
Bl, SBd, SBc). As shown in FIG. 4, it was confirmed that by setting the accumulation degree of the {200} texture to 1.5 or more, the springback amount was 12 mm or less, which was remarkably improved. As described above, by appropriately combining the equiaxed crystal ratio of the slab and the hot rolling conditions, even an austenitic stainless steel sheet with a relatively high P content is parallel to the rolled surface of the cold rolled sheet after finish annealing. It is possible to increase the degree of accumulation of the {200} texture in various planes, increase the n value, and significantly reduce the springback amount. The present invention has been made based on the above findings, and its gist is as follows.

1) {200} on a plane parallel to the rolled surface
Austenitic stainless cold-rolled steel sheet with a small amount of springback characterized by a degree of texture accumulation of 1.5 or more.

2) C: 0.01 to 0.1 wt%, Si: 0.05 to 3.0
wt%, Mn: 0.05 to 2.0 wt%, P: 0.04 wt% or less, S: 0.
03 wt% or less, Al: 0.1 wt% or less, Cr: 15-25 wt%, Ni:
5 to 15 wt%, N: 0.005 to 0.3 wt%, O: 0.007 wt% or less, the balance being Fe and inevitable impurities,
An austenitic stainless cold-rolled steel sheet with a small springback amount, characterized in that the degree of accumulation of {200} texture in a plane parallel to the rolled surface is 1.5 or more.

3) C: 0.01 to 0.1 wt%, Si: 0.05 to 3.0
wt%, Mn: 0.05 to 2.0 wt%, P: 0.04 wt% or less, S: 0.
03 wt% or less, Al: 0.1 wt% or less, Cr: 15-25 wt%, Ni:
5 to 15 wt%, N: 0.005 to 0.3 wt%, O: 0.007 wt% or less, Cu: 0.05 to 5.0 wt%, Co: 0.05 to 5.0 wt%
% Group, Mo: 0.05 to 5.0 wt%, W: 0.05 to 5.0 wt% group, Ti: 0.01 to 0.5 wt%, Nb: 0.01 to 0.5 wt%, V: 0.
01-0.5 wt%, Zr: 0.01-0.5 wt% group, REM: 0.001
~ 0.1 wt%, Y: 0.001-0.5 wt% group, B: 0.0003 ~
0.01 wt% and Ca: 0.0003 to 0.01 wt%, containing one or more selected from the rest, Fe and unavoidable impurities in the balance, and a {200} texture in a plane parallel to the rolling surface. Austenitic stainless cold-rolled steel sheet with a small springback amount characterized by a degree of accumulation of 1.5 or more.

4) A continuous cast slab having an equiaxed crystal ratio of 30% or more is heated and then roughly hot-rolled.
Austenitic stainless cold-rolled steel according to any one of 1) to 3) above, characterized in that hot finish rolling is performed at 1050 ° C. or higher and a rolling reduction is 15% or higher, and further cold rolling and finish annealing are performed. Steel plate manufacturing method.

5) A continuous casting slab having an equiaxed crystal ratio of 30% or more is heated and then roughly hot-rolled.
The hot finish rolling is performed at 1050 ° C. or higher and the rolling reduction is 15% or higher, and further hot-rolled sheet annealing, cold rolling and finish annealing are performed, according to any one of 1) to 3) above. A method for manufacturing an austenitic stainless cold-rolled steel sheet.

6) The method for producing an austenitic stainless cold-rolled steel sheet according to 4) or 5), wherein a lubricant is used in the final pass.

7) Manufacture of an austenitic stainless cold-rolled steel sheet according to any one of the above 4) to 6), in which a sheet bar obtained by rough rolling is joined with a preceding sheet bar and continuously finish rolled. Method.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. -Aggregation degree of {200} on a plane parallel to the rolled surface (sheet surface); Aggregation degree of {200} on a surface parallel to the rolled surface of the austenitic stainless cold-rolled steel sheet according to the present invention is 1.5.
That is all. This is because, as shown in FIG. 4, if the accumulation degree of this {200} texture is set to 1.5 or more, good characteristics of a springback amount of 12 mm or less can be obtained. Therefore, in the present invention, the accumulation degree of {200} on the plane parallel to the rolled surface is 1.5 or more, preferably 2.
Set to 0 or more.

The reasons for limiting the component composition will be described below. C: 0.01 to 0.1 wt% C is a strong austenitizing element and is added in an amount of 0.01 wt% or more, but if it is added in excess of 0.1 wt%, blowholes are likely to occur during welding. Therefore, the range is 0.01 to 0.1 wt%.

Si: 0.05 to 3.0 wt% Si is added as a deoxidizing agent in an amount of 0.05 wt% or more during melting.
However, if the amount added exceeds 3.0 wt%, descaling during hot rolling becomes difficult. Therefore, the range is 0.05 to 3.0 wt%.

Mn: 0.05 to 2.0 wt% Mn is required to be added in an amount of 0.05 wt% or more in order to stabilize austenite and fix S to improve hot workability. However, if the amount of Mn exceeds 2.0 wt%, descaling during hot rolling becomes difficult. Therefore, 0.05
The range is up to 2.0 wt%.

P: 0.04 wt% or less P is to increase the degree of accumulation of {111} in the plane parallel to the rolled surface of the hot rolled sheet and to develop {200} of the cold rolled annealed sheet, its amount is P. The smaller the number, the better. However, if it is manufactured by the method according to the present invention, up to 0.04 wt% can be tolerated, so P is set to 0.04 wt% or less.

S: 0.03 wt% or less S is an element that deteriorates hot workability and corrosion resistance, and it is desirable to reduce S. Its content is 0.
Up to 03 wt% is acceptable, so 0.03 wt% or less is set.

Al: 0.1 wt% or less Al is added as a deoxidizing agent when necessary during melting.
However, if the addition amount exceeds 0.1 wt%, descaling during hot rolling becomes difficult. Therefore, the upper limit is 0.1 wt%
And

Cr: 15-25 wt% Cr is an element that improves corrosion resistance and oxidation resistance,
It is necessary to add more than 15 wt%. However, the amount added
If it exceeds 25 wt%, the steel tends to become brittle. Therefore, 15
The range is up to 25 wt%.

Ni: 5 to 15 wt% Ni is an element that stabilizes austenite and improves toughness and corrosion resistance, and it is necessary to add 5 wt% or more. However, even if the added amount exceeds 15 wt%,
These effects saturate. Therefore, the range is 5 to 15 wt%.

N: 0.005 to 0.3 wt% N is an element that stabilizes austenite and improves corrosion resistance, and it is necessary to add 0.005 wt% or more. However, if the added amount exceeds 0.3 wt%, blowholes are likely to occur during welding. Therefore, 0.005
~ 0.3 wt% range.

O: 0.007 wt% O is an element that deteriorates the workability of steel, and it is desirable to reduce it, but its content is allowed up to 0.007 wt%.

Cu: 0.05 to 5.0 wt%, Co: 0.05 to 5.0 wt% Cu and Co are elements that stabilize austenite and improve corrosion resistance, and are added in an amount of 0.05 wt% or more. However, even if the addition amount of these exceeds 5.0 wt%, the effect is saturated. Therefore, for each element 0.05 ~
The range is 5.0 wt%.

Mo: 0.05 to 5.0 wt%, W: 0.05 to 5.0 wt% Mo and W are both elements that improve the corrosion resistance, and
More than 05wt% is added. However, the addition amount of these is 5.
If it exceeds 0 wt%, embrittlement tends to occur. Therefore, the range of each element is 0.05 to 5.0 wt%.

Ti: 0.01 to 0.5 wt%, Nb: 0.01 to 0.5 wt
%, V: 0.01 to 0.5 wt%, Zr: 0.01 to 0.5 wt% Ti, Nb, V, and Zr are all useful for suppressing the formation of Cr carbonitride during welding and suppressing sensitization. This element is added to 0.01 wt% or more. However, if the addition amount of these exceeds 0.5 wt%, large inclusions are generated and the toughness is significantly deteriorated. Therefore, 0.01 to 0.5 wt% for all elements
The range is.

B: 0.0003 to 0.01 wt% B is added in an amount of 0.0003 wt% or more in order to prevent secondary work embrittlement. However, if the amount exceeds 0.01 wt%, the workability decreases. Therefore, the range is 0.0003 to 0.01 wt%.

Ca: 0.0003 to 0.01 wt% Ca is an element useful in combination with Al ₂ O ₃ to reduce the strength of inclusions, increase ductility and improve workability. The effect is exhibited by adding 0.0003 wt% or more, but 0.01
If it exceeds wt%, the corrosion resistance decreases. Therefore, 0.0003-0.
The range is 01wt%.

REM: 0.001 to 0.1 wt%, Y: 0.001 to 0.
5 wt% REM and Y are elements that fix S and improve hot workability. All of these effects are obtained by adding 0.001 wt% or more, but if adding over 0.1 wt% for REM and over 0.5 wt% for Y, the toughness of the steel decreases. Therefore, REM is 0.001 ~
0.1 wt% and Y are added in the range of 0.001 to 0.5 wt%.

The manufacturing conditions of the steel sheet of the present invention will be described.・ Equiaxial crystal ratio of continuous cast slab
It is effective for enhancing the {111} texture in the plane parallel to the rolled surface of the hot rolled sheet, and subsequently cold rolling and finish annealing to develop the {200} texture in the plane parallel to the rolled surface of the steel sheet. is there. As shown in FIG. 2, even if the P content, which adversely affects the formation of texture, is 0.04 wt%, if a slab having a high equiaxed crystal ratio is hot-rolled under predetermined conditions, hot rolling is performed. The {111} texture of the sheet develops, the {200} texture of the finish-annealed cold rolled steel sheet increases, and springback can be suppressed to a low value. In order to increase the accumulation degree of {200} texture of the cold rolled steel sheet to 1.5 or more, it is necessary to set the equiaxed crystal ratio to 30% or more. Therefore, the equiaxed crystal ratio of the continuously cast slab is set to 30% or more. In order to produce a continuous casting slab having a high equiaxed crystal ratio of 30% or more, which is difficult to produce by the conventional technique, the casting start temperature during continuous casting may be lowered,
It is effective to increase the continuous casting speed or to stir by electromagnetic force after the start of casting.

The temperature of heating when rolling the slab is
The range of 1150 to 1300 ° C is preferable. Following heating, rough rolling and 4
Hot rolling including finish rolling by multi-pass rolling of 8 passes is performed. At this time, it is necessary to consider the final pass of finish rolling as follows.・ Temperature of the last pass of hot rolling: Set the temperature of the last pass of hot rolling to 1050
By setting the temperature to ℃ or higher, the degree of accumulation of {111} in the plane parallel to the rolled surface of the hot rolled sheet can be increased, and thereby the {200} texture of the finish annealed cold rolled sheet can be increased to 1.5 or more. Therefore, springback can be suppressed to a low value. Therefore, the temperature of the final pass of hot rolling (hot finish rolling) needs to be 1050 ° C or higher.

Final rolling reduction of hot rolling: The final rolling reduction in hot finish rolling also affects the formation of texture. As shown in FIG. 3, by setting the reduction ratio of the final pass in the hot finish rolling to 15% or more, the degree of accumulation of {111} texture in the plane parallel to the sheet surface of the hot rolled sheet is increased, The {200} texture of the annealed cold rolled steel sheet can be increased to 1.5 or more, and the spring back can be suppressed to a low value. Therefore, the rolling reduction in the final pass of hot rolling (hot finish rolling) needs to be 15% or more. The upper limit is not particularly specified, but is usually up to about 40% in consideration of the shape of the steel plate and the meandering of the steel plate. Although the strain rate of the final pass of hot rolling is not particularly specified, it is desirable to perform the strain rate in the range of 150 / sec or more from the viewpoint of texture formation.

Use of a lubricant in the final pass of hot rolling and continuous rolling: In the rolling in which the sheet bars obtained by rough rolling are joined and the finish rolling is continuously performed, the hot rolling is finished in the longitudinal direction of the coil. This is effective because the rolling reduction or the strain rate in the pass can be uniformly increased along the length of the coil, and uniform and excellent texture and thus springback resistance can be secured over the entire length of the coil. Further, the use of a lubricant brings about a uniform strain amount in the coil thickness direction, and the hot rolled sheet {11
1) Contribute to uniform development of texture. The use of lubricant and continuous rolling can be obtained by either one of
Since further effects can be obtained by using both means together, it is desirable to use both means together. The lubrication rolling method may be carried out by spraying a low melting glass lubricant on the steel sheet before rolling.

The hot rolled sheet produced under the above hot rolling conditions is
Since the recrystallization and the recovery have been completed in the hot rolled state, annealing (hot rolled sheet annealing) for this purpose is not particularly necessary. However, it is possible to subject this hot-rolled sheet to annealing mainly for softness. The hot rolled sheet thus obtained is subjected to cold rolling and finish annealing to obtain a product. At this time, the cold rolling condition is preferably a cold rolling reduction of 30 to 70%. This is because if the cold rolling reduction is less than 30%, {2
This is because the development of [00} tends to be insufficient, and when it exceeds 70%, another texture tends to develop. The finish annealing is preferably performed at 1050-1100 ° C. so that the grain size of the annealed plate is 6-9.

[0041]

Example Austenitic stainless steels having the compositions shown in Tables 1 and 2 were melted by a normal converter method, and a slab having a thickness of 200 mm was formed by a continuous casting process. In casting, the equiaxed crystal ratio was changed by changing the degree of electromagnetic stirring. These slabs are soaked in a slab heating furnace at 1150 to 1250 ° C for 1 to 2 hours, then 1100 to 1150 ° C
Rough rolling at a rolling reduction of 90% in total, and then final pass rolling of 7 passes was performed under the conditions shown in Tables 1 and 2 to obtain a hot-rolled sheet having a thickness of 4 mm. Further, these hot-rolled sheets were divided, and one was left as it was, and the other was further annealed at 1150 ° C. for 30 seconds in a continuous annealing furnace. The as-hot-rolled and hot-rolled annealed materials produced by the above method were mechanically prescaled by shot blasting and then
The sample was immersed in 24% sulfuric acid at 30 ° C. for 30 seconds, and further immersed in a mixed acid of 3% hydrofluoric acid and 12% nitric acid at 60 ° C. for 30 seconds to descale. The obtained hot-rolled sheet was subjected to cold rolling with a tandem rolling mill having a roll diameter of 250 mm to a sheet thickness of 1.0 mm, and after degreasing,
Finish annealing was performed at 1100 ° C for 30 seconds in a continuous annealing furnace.

The equiaxed crystal ratio of the slab, the {111} texture in the plane parallel to the rolling surface of the hot rolled sheet, and the {200} in the plane parallel to the rolling surface of the cold rolled sheet, which were obtained in the above manufacturing process, were obtained. } The texture, the grain size number, the n value, and the springback amount were obtained. The respective test conditions are as follows.・ Equiaxial crystal ratio: Percentage of equiaxed crystal relative to the cross-sectional area perpendicular to the casting direction of the slab, which can be observed by etching with aqua regia after polishing the cross-section of the slab. Those having a ratio (major axis / minor axis) in the range of 1 to 2 were defined as equiaxed crystals, and the area of this equiaxed crystal was expressed as an area percentage of the area of the cross section.・ Texture: The degree of integration of the texture is as follows: after polishing the surface parallel to the rolled surface ground to 1/4 of the plate thickness with # 1000 emery paper, etching with aqua regia to remove the processed texture, then inverse Method (Translated by Gentaro Matsumura: Curity New Edition X-ray Diffraction Theory (1986), pages 290 to 293) was measured as an intensity ratio with a random sample.・ N value: JISZB tensile test pieces parallel to the rolling direction, perpendicular to the rolling direction, and 45 ° direction are cut out from the steel sheet, and then JISZ
A tensile test was conducted by a method according to 22471, and true strains ε1 and ε2 at a tensile elongation of 5% and 15% and a true stress σ
It was calculated from the following equation using 1 and σ2. n = 1og (σ2 / σ1) / 1og (ε2 / ε1) ・ Spring back amount: A test piece with a width of 100 mm was cut out from the steel plate in the direction parallel to the rolling direction, at a right angle, and in the direction of 45 degrees. Handbook "(1987,
According to the U-shaped bending test method described on pages 417 to 418), the width dimension accuracy was evaluated when the ratio of the plate thickness to the bending radius was 1/6.

The equiaxed crystal ratio of the slab obtained by the above method is shown in Table 1.
Table 2 shows the {111} texture of the hot rolled sheet and {200} texture of the cold rolled sheet, the grain size number, the n value, and the springback amount in Table 3 and Table 4, respectively. No. 3, 5, 10-13, 15, 19, 21, which correspond to the examples of the present invention,
25, 27, 29, 31, 33, 35, 37, 39, 4
No. 1,43,45,47, the degree of accumulation of {200} on the surface parallel to the rolled surface of the cold rolled and annealed plate was 1.5 or more, and the test was conducted in any direction of parallel, right angle and 45 degrees to the rolling direction. The springback amount of one piece is 12 mm or less, which is good. Further, even within the scope of the present invention, 12 subjected to continuous rolling, 10 subjected to lubrication, and 13 subjected to continuous rolling and lubrication were more parallel to the rolling surface than 11 subjected to neither continuous rolling nor lubrication. The degree of accumulation of {200} on the flat surface is high, and the springback amount of the test piece in any direction parallel to the rolling direction, right angle, or 45 degrees is good. In addition, in this example, all the austenite grain size numbers were 8, and no skin roughening occurred when the springback amount was measured. On the other hand, 1,6 to 8,16,17,2 in which the slab has an isoprene crystal ratio of less than 30%
2,23,32,36,38,42,44, 1,2,4,6,8,9,1 whose finishing temperature of hot rolling is less than 1050 ℃
4,16,18,20,22,24,26,30,3
2, 36, 38, 40, 46, 28, 34, 44 in which the rolling reduction of hot rolling is less than 15%, and 22 to 27 in which the amount of P is more than 0.04% have an integration degree of {200}. It is less than 1.5, and the springback amount is inferior to more than 12 mm.

[0044]

[Table 1]

[0045]

[Table 2]

[0046]

[Table 3]

[0047]

[Table 4]

[0048]

As described above, according to the present invention, a texture having a high {200} integration degree in a plane parallel to the rolled surface can be obtained, and the austenite with a small springback and a fine crystal grain. It becomes possible to manufacture a cold-rolled stainless steel sheet. Further, according to the method of the present invention, the above effect can be obtained even if the P amount is in a relatively high range of 0.04 wt%, so that an economically excellent austenitic stainless cold-rolled steel sheet can be produced. It will be possible. Therefore, by using the present invention, it becomes possible to easily and inexpensively manufacture a press-formed product having a good shape, such as a bathtub, a pot, tableware, and a sink.

[Brief description of drawings]

FIG. 1 shows the relationship between the degree of accumulation of {111} texture in the plane parallel to the rolled surface of hot rolled SUS304 and the degree of accumulation of {200} texture in the plane parallel to the rolled surface of cold rolled sheet. It is a figure.

FIG. 2 is a diagram showing an influence of a slab equiaxed crystal ratio on an accumulation degree of {111} texture in a plane parallel to a rolled surface of a hot rolled sheet of SUS304 (0.04 wt% P).

FIG. 3 is a diagram showing the effect of the reduction ratio of the final pass of hot rolling finish rolling on the degree of integration of {111} texture parallel to the rolling surface in the hot rolled sheet of SUS304 (0.04 wt% P).

FIG. 4 is a diagram showing the relationship between the accumulation degree of {200} texture parallel to the rolled surface, the amount of springback, and the n value in the cold rolled sheet of SUS304 (0.04 wt% P).

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-52-60231 (JP, A) JP-A-4-224622 (JP, A) JP-A-10-36946 (JP, A) JP-B 6- 17515 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22C 38/00-38/60 B21B 3/02 C21D 8/00-8/10 C21D 9/46-9/48

Claims (7)

(57) [Claims] 1. A cold rolled austenitic stainless steel sheet with a small springback amount, characterized in that the degree of accumulation of {200} texture in a plane parallel to the rolled surface is 1.5 or more. 2. C: 0.01 to 0.1 wt%, Si: 0.05 to 3.0 wt%
%, Mn: 0.05 to 2.0 wt%, P: 0.04 wt% or less, S: 0.03w
t% or less, Al: 0.1 wt% or less, Cr: 15-25 wt%, Ni: 5
˜15 wt%, N: 0.005 to 0.3 wt%, O: 0.007 wt% or less, the balance consisting of Fe and unavoidable impurities, and the degree of accumulation of {200} texture in the plane parallel to the rolling surface is
Austenitic stainless cold-rolled steel sheet with a small springback amount characterized by being 1.5 or more. 3. C: 0.01 to 0.1 wt%, Si: 0.05 to 3.0 wt%
%, Mn: 0.05 to 2.0 wt%, P: 0.04 wt% or less, S: 0.03w
t% or less, Al: 0.1 wt% or less, Cr: 15-25 wt%, Ni: 5
-15 wt%, N: 0.005-0.3 wt%, O: 0.007 wt% or less, Cu: 0.05-5.0 wt%, Co: 0.05-5.0 wt%
%, Mo: 0.05 to 5.0 wt%, W: 0.05 to 5.0 wt%, Ti: 0.
01 to 0.5 wt%, Nb: 0.01 to 0.5 wt%, V: 0.01 to 0.5 wt%
%, Zr: 0.01 to 0.5 wt%, REM: 0.001 to 0.1 wt%,
Y: 0.001 to 0.5 wt%, B: 0.0003 to 0.01 wt% and C
a: contains any one or two or more selected from 0.0003 to 0.01 wt%, the balance consisting of Fe and unavoidable impurities, and the degree of accumulation of {200} texture in a plane parallel to the rolled surface is Austenitic stainless cold-rolled steel sheet with a small springback amount characterized by being 1.5 or more. 4. A continuously cast slab having an equiaxed crystal ratio of 30% or more is heated and then roughly hot-rolled, and then a final pass is performed at a temperature of
The hot austenitic stainless steel cold rolled steel sheet according to any one of claims 1 to 3, wherein hot finish rolling is performed at 1050 ° C or higher and a rolling reduction is 15% or higher, and further cold rolling and finish annealing are performed. Manufacturing method. 5. A continuous cast slab having an equiaxed crystal ratio of 30% or more is heated and then roughly hot-rolled, and then a final pass is performed at a temperature of
4. Hot finish rolling at 1050 ° C. or higher and a rolling reduction of 15% or higher, and further hot-rolled sheet annealing, cold rolling and finish annealing are performed, The austenite according to claim 1. Of cold-rolled stainless steel sheet. 6. A lubricant is used in the final pass.
Alternatively, the method for producing an austenitic stainless cold-rolled steel sheet according to Item 5. 7. A sheet bar obtained by rough rolling is joined to a preceding sheet bar and continuously finish-rolled.
7. The method for producing an austenitic stainless cold-rolled steel sheet according to any one of items 1 to 6.