JP2992216B2 - Manufacturing method of high gloss stainless steel strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a high-gloss stainless steel strip.

[0002]

2. Description of the Related Art Conventionally, a cold rolled stainless steel strip is subjected to cold rolling using a steel alloy work roll in a Sendzimir mill or the like having a work roll diameter of 150 mm or less after annealing and pickling a hot rolled steel strip. After finish pickling or bright bright annealing, finish temper rolling at a rolling reduction of 1.2% or less is performed.

[0003] The stainless cold-rolled steel strip is, for example, SU
In the case of ferrites represented by S430, the surface after production is often used as it is, and a product after finish temper rolling is required to have excellent surface gloss. Further, in the case of an austenitic material represented by SUS304, buffing is often performed after finish temper rolling, and it is important to exhibit excellent surface gloss after this buffing.

Further, as a method for efficiently producing a cold rolled stainless steel strip, a method has been adopted in which cold rolling is continuously performed in one direction by a cold tandem mill using a work roll having a large diameter of 150 mmφ or more. However, as for the surface roughness of the steel strip cold-rolled with the large-diameter work roll, extremely large roughness of the surface obtained by annealing and pickling the hot-rolled steel strip remains after the cold rolling, and the cold-rolling using the small-diameter work roll is performed. The product was not able to be used at all for applications requiring a surface gloss, since it remained as a larger roughness than that of hot rolling.

Conventionally, in cold rolling using a small-diameter work roll such as a Sendzimir mill, for example, as disclosed in JP-A-60-261609, a method in which a ceramic-coated roll is used together with a low-viscosity rolling oil. Has been proposed. This is to prevent the so-called heat scratch in high-speed rolling by using a ceramic-coated roll for rolling at all times, and to prevent oil pits generated during cold rolling by low-viscosity rolling oil. To improve the gloss. However, as in the embodiment, it is applied only to cold rolling using a small-diameter work roll such as a Sendzimir mill,
This is different from the rolling of stainless steel strip by a cold tandem mill using a large-diameter work roll as in the present invention.
That is, in rolling using a small-diameter work roll, heat streaks easily occur because the oil film thickness of the rolling oil introduced between the roll and the steel strip is extremely thin, and this prevention technology is important, and the ceramic is coated. Roles had been applied. Regarding gloss, even if the roll material is changed, the difference does not appear because the oil film thickness is extremely thin, and instead of the roll material, the viscosity of the rolling oil is reduced to reduce oil pits and improve gloss. I was On the other hand, in cold rolling using a large-diameter work roll, since the oil film thickness of the rolling oil introduced between the roll and the steel strip is extremely large, heat streaks occur as in the case of using a small-diameter work roll. The problem is small, and the problem of gloss reduction is large. The present invention has been made by finding new knowledge focusing on the roll material in order to improve gloss in cold rolling using the large-diameter work roll.

As a method for solving this kind of surface gloss reduction problem in a stainless steel strip, a method disclosed in
As described in JP-A 61-49701, a method of devising a combination of work rolls has been proposed. Further, for example, Japanese Patent Publication No. 3-34406, Japanese Patent Publication No. 57-13362,
As described in, for example, Japanese Patent Application Laid-Open No. 57-41801, a method has been proposed in which the work roll roughness during cold rolling is set to a specific range. However, if only these methods are adopted, the extremely high roughness of the steel strip surface annealed and pickled after hot rolling remains after cold rolling, so that the surface gloss of the finished steel strip must be sufficiently improved. And further improvement was greatly desired.

[0007]

SUMMARY OF THE INVENTION The present invention solves the problem of lowering of surface gloss, which has conventionally been encountered when a stainless steel strip is rolled by a cold tandem mill, and efficiently produces high-quality materials. Aim.

[0008]

The method for producing a stainless steel pretreated steel strip for cold rolling according to the present invention according to the first aspect of the present invention comprises the steps of: rolling a stainless steel strip by using a cold tandem mill; A work roll made of a WC alloy is used for at least the first stand and / or the final stand.
Rolling is performed by using a work roll of 150 mm or more.

According to a second aspect of the present invention, there is provided a method of manufacturing a stainless steel pretreated steel strip for cold rolling according to the present invention, wherein at least a first stand and / or a stainless steel strip is manufactured by rolling a stainless steel strip using a cold tandem mill. Alternatively, a work roll made of a WC alloy is used for the final stand, and the first stand is rolled with a work roll having a surface roughness of Ra 2.50 μm or less and 0.50 μm or more. Rolled with a work roll having a surface roughness of not more than the average roughness of the work roll of the stand immediately before the stand, and a work roll having a surface roughness of not more than Ra 0.15 μm and not less than 0.05 μm in the final stand. It is intended to be rolled.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a work roll comprising a WC alloy roll outer layer having a thickness of 5 mm or more is further used as the WC alloy work roll. It is like that.

[0011]

Conventionally, it has been known that in order to improve the surface gloss of a cold-rolled stainless steel strip, it is better to reduce the surface roughness of the steel strip after cold rolling which affects the surface roughness of the product. .

However, in the study of the present inventors, the surface roughness of the steel strip after the above-described cold rolling was as follows:
That is, they found that a part of the surface roughness of the steel strip annealed and pickled after hot rolling was left after cold rolling.

The surface roughness of the steel strip annealed and pickled after hot rolling is described below. Average roughness R in the final finished product
a In the production of cold-rolled stainless steel strips with a surface roughness of 0.1 μm or less, the surface roughness of the steel strip immediately after annealing and pickling of the hot-rolled steel strip is determined by mechanical removal such as shot blasting during pickling. By the scale treatment and the pickling treatment such as sulfuric acid, the average roughness R
a It has a remarkably large roughness of 2 to 4 μm.

In general, however, a large amount of rolling oil is supplied to the roll and the steel strip from the inlet of the rolling mill during cold rolling.
This is performed in order to manufacture the steel strip stably by simultaneously performing the lubrication and the cooling with the rolling oil to prevent the occurrence of seizure flaws such as heat streaks.

Therefore, on the entry side of the cold rolling mill, rolling oil having a thickness of several μm or more adheres to the roll and the surface of the steel strip,
Rolling oil accumulates in extremely large dents on the surface of the steel strip annealed and pickled after hot rolling, and is bitten by the roll bite. The oil that has accumulated in the dent has no escape during the contact between the roll and the steel strip in the roll bite, and the oil is rolled while being sealed.

In general, liquids including rolling oil are much less likely to be compressed than gases such as air, so that the dents that contain oil during rolling are somewhat smaller than before rolling.
Most remains after rolling.

As described above, the surface roughness of the steel strip before cold rolling remains even after cold rolling and significantly impairs the surface gloss of the product.

Therefore, in order to obtain a steel strip having a good surface gloss, it is preferable to reduce the concave portions of the surface roughness of the steel strip at the start of cold rolling during rolling. That is, during the cold rolling, the roughness of the roll surface is sufficiently brought into contact with the steel strip surface so that the recesses of the steel strip surface roughness before the cold rolling are sufficiently reduced.

However, in a cold tandem mill using a large-diameter work roll, since the roll diameter is larger than that of a conventional small-diameter work roll, rolling oil is sufficiently interposed between the roll and the steel strip. It is difficult to bring the roughness of the roll surface into sufficient contact with the steel strip surface.

For this purpose, the inventors of the present invention have found that the following method is preferable. (a) Rolling oil must not be drawn between the roll and the steel strip. (b) Create sufficient pressure between the roll and the steel strip.

In order to make the effects of (a) and (b) work more effectively, the present inventors focused on the Young's modulus of the roll. It is understood that when the Young's modulus of the roll increases, the biting angle can be increased, and the rolling oil shown in (a) can be hardly drawn.

When the Young's modulus of the roll increases,
It was found that the rolling oil became difficult to be drawn in, the pressure between the roll and the steel strip increased, and the effect shown in (b) was also obtained.

Therefore, it has been found that a WC alloy roll is preferably used as a method for increasing the Young's modulus of the roll as much as possible. WC alloy is, for example, WC50 ~
99% to 30% Co0 and / or 30% Ni0 and / or
Alternatively, it is better to combine the other.

The WC alloy roll may be applied to all stands of the cold tandem mill, but may be applied to at least the first stand and / or the last stand in consideration of the effect of improving gloss and cost.

If the present invention is applied to the first stand, the above-mentioned concave portions having a large roughness on the surface of the cold-rolled material can be sufficiently reduced, and the surface gloss can be improved. Furthermore, in the case of a normal roll material, when a large roughness having an average roughness Ra of 0.5 μm or more is applied to a work roll, it is difficult to maintain the roughness by abrasion due to short distance rolling, but in a WC alloy roll, The wear can be prevented and large roughness can be maintained for a long time.

If applied to the final stand,
The recesses on the surface of the cold-rolled material that could not be reduced by the immediately preceding stand can be sufficiently reduced, and the gloss can be significantly improved.
Furthermore, when a normal roll material is rolled for a long time using a work roll having a relatively small average roughness Ra of 0.15 μm or less, the large roughness of the steel sheet is transferred to the roll and the roughness increases, resulting in a decrease in gloss. There was a problem of lowering. On the other hand, in the WC alloy, the roll roughness does not increase,
High gloss can be maintained for a long time.

Even if a WC alloy is applied to a conventional small-diameter work roll, the angle of engagement between the roll and the steel strip is originally large because the work roll is a small-diameter work roll. Forged steel, cold dies, high-speed steel) and W
The difference in the amount of rolling oil drawn in from the C alloy roll is small, making it difficult to reduce the film thickness of the rolling oil interposed between the roll and the steel strip. The effect of reducing the large roughness of the cold rolled material surface is as follows. , WC alloy rolls and ordinary steel alloy rolls.

However, in the case of a large-diameter work roll such as a cold tandem mill, the influence of the Young's modulus of the roll on the amount of rolling oil drawn in is extremely large, and the effect of the rolling oil interposed between the roll and the steel strip is large. The thickness can be easily reduced.

In the present invention, an integral roll of a WC alloy may be used, but due to the high cost, the roll barrel portion is made of a WC alloy and the roll neck portion is made of a conventional steel-based alloy or a roll barrel. Preferably, only the surface layer of the portion is made of a WC alloy. Furthermore, as a method of forming the WC alloy only on the surface layer of the roll barrel portion, the WC alloy may be fitted to a conventional steel-based alloy or sprayed. However, in order to increase the Young's modulus, the thickness is preferably 5 mm or more. desirable.

The present inventors further studied a method for improving gloss. That is, in the above-described operation (a), the cause of the rolling oil being drawn between the roll and the steel strip is a hydrodynamic force acting on the rolling oil, and this force greatly changes depending on the rolling conditions. Therefore, various rolling conditions were examined to prevent rolling oil from being drawn in between the roll and the steel strip, and various rolling conditions for sufficiently contacting the roll and the steel strip were examined. As a result, it has been found that the work roll diameter of the final stand, which is a component of the first aspect of the invention, should be reduced. The stand of the cold tandem mill, which most affects the surface gloss of the finished steel strip, is the final stand. Therefore,
The optimum roll diameter was examined by variously changing the roll diameter of the final stand. As a result, the roll diameter of the final stand
We found that it is better to make it 400mm or less. In order to apply this work roll to a cold tandem mill, the roll diameter is preferably 150 mm or more from the viewpoint of roll strength.

Further, the following has been grasped as a constituent element of the invention of claim 2 for preventing the rolling oil from being drawn between the roll and the steel strip. That is, it is preferable to increase the work roll roughness, especially the average roughness Ra is 0.5 μm or more.
We have found that it is better to make it less than 0 μm. Further, in order to sufficiently reduce the recesses of the surface roughness of the steel strip before the cold rolling during the cold rolling, the work roll roughness described above may be applied to the first stand having the smallest deformation resistance of the steel strip. Figured out. However, if the second and subsequent stands are rolled with a large roughness, the roughness remains after the cold rolling and the surface gloss of the steel strip decreases. Then, the gloss of the steel strip finished by cold rolling with variously changing the work roll roughness of each stand was examined. As a result, it was found that the glossiness was improved as a result of the roll roughness of each stand being successively reduced as the stand became a rear stand. Here, sequentially reducing the roll roughness includes the case of the same roughness. In other words, this means that the roll roughness of the subsequent stand is not increased on the way. Further, it was necessary to reduce the roll roughness of the final stand, and the gloss of the final stand was changed by variously changing the roll roughness. As a result, it was found that when the average roughness Ra was 0.15 μm or less, good gloss was obtained. Here, the roll roughness is desirably Ra 0.15 μm or less.
μm or more is good. That is, when the roll roughness becomes extremely small, the roll and the steel strip slip and rolling becomes unstable.

[0032]

【Example】

(Example of Group A (Invention of Claim 1)) (Example 1) (Table 1) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention, using a steel strip 0, a 5-stand cold tandem mill is used for all stands, and the roll inner core, which is an example of the method of the present invention, is made of high-speed steel.
A work roll fitted with the contained WC alloy was applied, and the work roll diameter of the final stand was 400 mm or less, and the steel strip was cold-rolled from a material thickness of 4.0 mm to a finish thickness of 1.0 mm.

As a comparative example, a work roll of a WC alloy containing 10% of Co is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. As cold rolled.

As a comparative example, a work roll using a normal 5% Cr forged steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was 400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed in the same manner as above.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.0%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was measured according to JIS Z8741 Glossiness Measurement Method 5 (GS20 °).
0 was A, 600 to 800 was B, 400 to 600 was C, and 400 or less was D, and evaluated on a 5-point scale.

From the results shown in Table 1, the cold rolled stainless steel strip produced by the method of the present invention had significantly better gloss than the steel strip produced in the comparative example and the conventional example.

[Table 1]

(Example 2) (Table 2) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention, an integrated work roll of a WC alloy containing 30% of Co, which is an example of the method of the present invention, is provided from a first stand to a third stand by a five-stand cold tandem mill using a 0 steel strip. Apply and set the work roll diameter of the final stand to φ400mm or less, and make the steel strip 5.0m thick.
Cold rolled from m to a finished thickness of 2.0 mm.

As a comparative example, 30% Co was added from the first stand to the third stand in a five-stand cold tandem mill.
The work roll of the WC alloy to be contained was applied, and the work roll of the final stand was cold-rolled with the large diameter exceeding 400 mm as before.

As a comparative example, a work roll using ordinary 5% Cr steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using ordinary 5% Cr steel is applied to all stands in a five-stand cold tandem mill, and the work roll of the final stand is still large in diameter exceeding 400 mm as before. Cold rolling was performed similarly in the case of rolling.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.2%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 2, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 2]

Example 3 (Table 3) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention, using a 0 steel strip, the roll shaft core, which is an example of the method of the present invention, is formed into a cold die steel on the final fifth stand by a 5-stand cold tandem mill, and Ni is added to the outer periphery of the roll by 5%. Apply a work roll fitted with the contained WC alloy, and set the work roll diameter of the final stand to φ400mm.
As below, finish the steel strip from 3.0mm in material thickness to 0.3mm in finish thickness.
Cold rolled to 7mm.

As a comparative example, a work roll of a WC alloy containing 5% of Ni was applied to the fifth stand in a five-stand cold tandem mill, and the work roll of the final stand had a large diameter exceeding φ400 mm as before. Cold rolled as it was.

Further, as a comparative example, a work roll using a normal 5% Cr forged steel was applied to all stands in a 5-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 0.8%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 3, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 3]

Example 4 (Table 4) SUS43 as an example of a ferritic stainless steel strip
Using a steel strip 0, as an example of the method of the present invention, a semi-high-speed steel roll neck as an example of the method of the present invention was used for the fourth stand and the fifth stand in a 5-stand cold tandem mill, and Ni was contained in the roll barrel at 15%. A work roll provided with a WC alloy to be contained is applied, and the work roll diameter of the final stand is φ400 mm or less, and the steel strip has a material thickness of 4.0 mm.
Cold rolled to an intermediate thickness of 1.3 mm.

As a comparative example, 15% Ni was added to the fourth and fifth stands by a five-stand cold tandem mill.
The work roll of the WC alloy to be contained was applied, and the work roll of the final stand was cold-rolled with the large diameter exceeding 400 mm as before.

As a comparative example, a work roll using ordinary 5% Cr forged steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

[0055] These steel strips were then subjected to an intermediate thickness milling process by a Sendzimir mill using a small-diameter work roll of a cold die.
Rolling was performed in five passes from 1.3 mm to a finished thickness of 1.0 mm, finish annealing, pickling, and temper rolling at an elongation of 1.0%.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 4, the stainless steel cold-rolled steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 4]

(Example 5) (Table 5) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 304 steel strip, a 5-stand cold tandem mill is used for all stands, and the inner core of the roll, which is an example of the method of the present invention, is made of high-speed steel.
A work roll fitted with a WC alloy containing 10% is applied, and the work roll diameter of the final stand is set to φ400mm or less.
Until cold-rolled.

As a comparative example, a work roll of a WC alloy containing 10% of Co was applied to all stands in a five-stand cold tandem mill, and the work roll of the final stand had a large diameter exceeding φ400 mm as before. As cold rolled.

As a comparative example, a work roll using ordinary 5% Cr forged steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

Then, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 0.6%, and subjected to three passes of # 600 buffing to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 5, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 5]

Example 6 (Table 6) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 304 steel strip, an integrated work roll of a WC alloy containing 30% of Co, which is an example of the method of the present invention, is provided from the third stand to the fifth stand using a five-stand cold tandem mill. Apply and set the work roll diameter of the final stand to φ400mm or less,
Cold-rolled from 5.0 mm to a finished thickness of 2.3 mm.

As a comparative example, 30% Co was added from the third stand to the fifth stand using a five-stand cold tandem mill.
The work roll of the WC alloy to be contained was applied, and the work roll of the final stand was cold-rolled with the large diameter exceeding 400 mm as before.

Further, as a comparative example, a work roll using ordinary 5% Cr forged steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using ordinary 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 0.8%, and subjected to buffing under the same conditions as described above to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 6, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 6]

(Example 7) (Table 7) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 304 steel strip, a 5-stand cold tandem mill is used as the first stand, and a roll core, which is an example of the method of the present invention, is made of cold die steel. The work roll diameter of the final stand is set to φ400 mm or less by applying a work roll fitted with a WC alloy to be processed.
mm.

As a comparative example, a work roll of a WC alloy containing 5% of Ni was applied to the first stand in a five-stand cold tandem mill, and the work roll of the final stand had a large diameter exceeding φ400 mm as before. Cold rolled as it was.

Further, as a comparative example, a work roll using ordinary 5% Cr forged steel was applied to all stands in a five-stand cold tandem mill, and the work roll diameter of the final stand was φ400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

Then, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.0%, and subjected to one pass of # 400 buffing to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 7, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 7]

(Example 8) (Table 8) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention using a 304 steel strip, a semi-high-speed steel roll neck as an example of the method of the present invention is used for the fourth stand and the fifth stand in a five-stand cold tandem mill, and Ni in the roll barrel is 15%. Applying a work roll provided with the contained WC alloy, making the work roll diameter of the final stand φ400 mm or less, and making the steel strip 3.0 mm thick
From 1. to an intermediate thickness of 1.30 mm.

As a comparative example, a work roll of WC cemented carbide was applied to the fourth stand and the fifth stand in a five-stand cold tandem mill, and the work roll of the final stand had a large diameter exceeding φ400 mm as before. Cold rolling was performed as it was.

Further, as a comparative example, a work roll using ordinary 5% Cr forged steel was applied to all stands in a 5-stand cold tandem mill, and the work roll diameter of the final stand was 400 mm or less, and cold rolling was performed.

Further, as a conventional example, a work roll using a normal 5% Cr forged steel is applied to all the stands in a five-stand cold tandem mill, and the work roll of the final stand has a large diameter exceeding φ400 mm as before. Cold rolling was performed similarly in the case of rolling.

These steel strips were then subjected to a cluster type rolling mill using a high-speed small-diameter work roll to an intermediate thickness of 1.3 mm.
Cold rolled to a finish thickness of 0.8mm, finish annealing, pickling, temper rolling at an elongation of 0.6%, and buffing with # 600.
After passing, the gloss of the steel strip surface was investigated.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 8, the cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 8]

(Example of Group B (Invention of Claim 2)) (Example 9) (Table 9) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention, using a 0 steel strip, the work roll roughness of the first stand is set to Ra 0.5 μm or more and the work roll roughness of the final stand is set to Ra 0.15 μm or less in a five-stand cold tandem mill. A work roll in which the inner core of the roll, which is an example of the method of the present invention, is made of high-speed steel, and a WC alloy containing 10% of Co is fitted on the outer periphery of the roll, is applied to all the stands. 1.0m
m.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll having a roughness of 0.15 μm or more and a work roll of a WC alloy containing 10% Co were applied to all stands and cold rolled.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or more, and the work roll roughness of the final stand is Ra
Cold rolling was performed with a work roll made of ordinary 5% Cr forged steel applied to all stands to a thickness of 0.15 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll having a roughness of 0.15 μm or more was subjected to the same cold rolling in the case where the work roll was rolled using a normal work roll using 5% Cr forged steel on all stands.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.0%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 9, the stainless steel cold-rolled steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 9]

(Example 10) (Table 10) SUS43 as an example of a ferritic stainless steel strip
Using a steel strip 0, as an example of the method of the present invention, the work roll roughness of the first stand is set to Ra 0.5 μm or more and the work roll roughness of the final stand is set to Ra 0.15 μm or less in a five-stand cold tandem mill. The first stand to the third
An integrated work roll of a WC alloy containing 30% of Co, which is an example of the method of the present invention, was applied to the stand, and the steel strip was cold-rolled from a material thickness of 5.0 mm to a finished thickness of 2.0 mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
Conventional work roll roughness of 0.15 μm or more
A work roll of a WC alloy containing 30% of Co was applied from the stand to the third stand and cold rolled.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or more, and the work roll roughness of the final stand is Ra
Cold rolling was performed with a work roll made of ordinary 5% Cr forged steel applied to all stands to a thickness of 0.15 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of 0.15 μm or more was subjected to the same cold rolling in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

Then, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.2%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 10,
The cold-rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 10]

(Example 11) (Table 11) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention, using a 0 steel strip, the work roll roughness of the final stand is set to Ra 0.15 μm or less using a five-stand cold tandem mill, and the roll axis, which is an example of the method of the present invention, is attached to the final fifth stand. Was used as a cold die steel, and a work roll in which a WC alloy containing 5% of Ni was fitted around the roll was applied, and the steel strip was cold-rolled from a material thickness of 3.0 mm to a finished thickness of 0.7 mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll having a roughness of 0.15 μm or more was used, and a work roll of a WC alloy containing 5% of Ni was applied to the fifth stand to perform cold rolling.

As a comparative example, the work roll roughness of the final stand was Ra 0.1 using a five-stand cold tandem mill.
Cold rolling was performed with a work roll using ordinary 5% Cr forged steel applied to all the stands to 5 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of 0.15 μm or more was subjected to the same cold rolling in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

Then, these steel strips were finish-annealed, pickled, and temper-rolled at an elongation of 0.8%, and the gloss of the steel strip surface was examined.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 11,
The cold-rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 11]

(Example 12) (Table 12) SUS43 as an example of a ferritic stainless steel strip
As an example of the method of the present invention using a 0 steel strip, the work roll roughness of the final stand is Ra 0.15 μm or less in a five-stand cold tandem mill, and the fourth and fifth stands are examples of the method of the present invention. A work roll with semi-high-speed steel as the roll neck and a WC alloy containing 15% Ni in the roll barrel is applied.
Cold rolled from m to an intermediate thickness of 1.3 mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
Conventional work roll roughness of 0.15 μm or more, WC containing 15% Ni in the fourth and fifth stands
Cold rolling was performed using an alloy work roll.

As a comparative example, the work roll roughness of the final stand was Ra 0.1 using a five-stand cold tandem mill.
Cold rolling was performed with a work roll using ordinary 5% Cr forged steel applied to all the stands to 5 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of 0.15 μm or more was subjected to the same cold rolling in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

These steel strips were then subjected to a Sendzimir rolling mill using a small diameter work roll of a cold die to an intermediate thickness of 1.3 m.
5 pass rolling from m to finish thickness 1.0mm, finish annealing,
It was pickled and temper-rolled at an elongation of 1.0%.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 12,
The cold-rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 12]

(Example 13) (Table 13) SUS as an example of an austenitic stainless steel strip
Using a 304 steel strip, as an example of the method of the present invention, the work roll roughness of the first stand is set to Ra 0.5 μm or more and the work roll roughness of the final stand is set to Ra 0.15 μm or less in a five-stand cold tandem mill. A work roll in which the inner core of the roll, which is an example of the method of the present invention, is made of high-speed steel, and a WC alloy containing 10% of Co is fitted on the outer periphery of the roll, is applied to all the stands.
Cold rolled to 1.3mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll having a roughness of 0.15 μm or more was used, and a work roll of a WC alloy containing 10% of Co was applied to all stands and cold rolled.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or more, and the work roll roughness of the final stand is Ra
Cold rolling was performed with a work roll made of ordinary 5% Cr forged steel applied to all stands to a thickness of 0.15 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
Cold rolling was performed similarly in the case where a conventional work roll roughness of 0.15 μm or more and a work roll using ordinary 5% Cr forged steel were applied to all stands.

Then, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 0.6%, and subjected to three passes of # 600 buffing to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 13,
The cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 13]

Example 14 (Table 14) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 304 steel strip, the work roll roughness of the final stand is set to be Ra 0.15 μm or less using a five-stand cold tandem mill, and the third stand to the fifth stand are used.
An integrated work roll of a WC alloy containing 30% of Co, which is an example of the method of the present invention, was applied to the stand, and the steel strip was cold-rolled from a material thickness of 5.0 mm to a finished thickness of 2.3 mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
Conventional work roll roughness of 0.15 μm or more, WC containing 30% Co from the third stand to the fifth stand
Apply alloy work rolls and reduce the # 5 stand rolling reduction
Cold rolled as 12%.

Further, as a comparative example, the work roll roughness of the final stand was Ra 0.1 using a five-stand cold tandem mill.
Cold rolling was performed with a work roll using ordinary 5% Cr forged steel applied to all the stands to 5 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of not less than 0.15 μm was used, and cold rolling was similarly performed in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 0.8%, and subjected to buffing under the same conditions as described above to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 14,
The cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 14]

(Example 15) (Table 15) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 304 steel strip, the work roll roughness of the first stand is set to Ra 0.5 μm or more and the work roll roughness of the final stand is set to Ra 0.15 μm or less in a five-stand cold tandem mill. In the first stand, the roll core, which is an example of the method of the present invention, is made of cold die steel,
A work roll in which a WC alloy containing 5% of Ni was fitted on the outer periphery of the roll was applied, and the steel strip was cold-rolled from a material thickness of 3.0 mm to a finish thickness of 0.98 mm.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll roughness of 0.15 μm or more was used, and a work roll of a WC alloy containing 5% of Ni was applied to the first stand and cold rolled.

As a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or more, and the work roll roughness of the final stand is Ra
Cold rolling was performed with a work roll made of ordinary 5% Cr forged steel applied to all stands to a thickness of 0.15 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of not less than 0.15 μm was used, and cold rolling was similarly performed in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

Thereafter, these steel strips were finish-annealed, pickled, temper-rolled at an elongation of 1.0%, and subjected to one pass of # 400 buffing to examine the gloss of the steel strip surface.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 15,
The cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 15]

(Example 16) (Table 16) SUS as an example of an austenitic stainless steel strip
As an example of the method of the present invention, using a 430 steel strip, the work roll roughness of the final stand is set to Ra 0.15 μm or less using a five-stand cold tandem mill.
WC containing semi-high-speed steel as a roll neck, which is an example of the method of the present invention, and a roll barrel containing 15% Ni
Apply a work roll provided with an alloy and apply the steel strip to the material thickness.
Cold-rolled from 3.0 mm to an intermediate thickness of 1.30 mm.

Further, as a comparative example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
A conventional work roll having a roughness of 0.15 μm or more was used, and a work roll of a WC alloy was applied to the fourth and fifth stands to perform cold rolling.

As a comparative example, the work roll roughness of the final stand was Ra 0.1 using a five-stand cold tandem mill.
Cold rolling was performed with a work roll using ordinary 5% Cr forged steel applied to all the stands to 5 μm or less.

Further, as a conventional example, the work roll roughness of the first stand was Ra 0.5 using a five-stand cold tandem mill.
μm or less, and the work roll roughness of the final stand is Ra
The conventional work roll roughness of not less than 0.15 μm was used, and cold rolling was similarly performed in the case where a work roll using ordinary 5% Cr forged steel was applied to all stands.

[0127] These steel strips were thereafter subjected to a cluster type rolling mill using a high-speed small-diameter work roll to have an intermediate thickness of 1.3 mm.
Cold-rolled to a finish thickness of 0.8 mm, finish annealing, pickling, temper rolling at an elongation of 0.6%, and buff polishing with # 600.
After passing, the gloss of the steel strip surface was investigated.

The surface gloss of these cold rolled stainless steel strips was evaluated in the same manner as in Example 1. From the results shown in Table 16,
The cold rolled stainless steel strip manufactured by the method of the present invention had significantly better gloss than the steel strips manufactured in the comparative example and the conventional example.

[Table 16]

[0129]

As described above, the stainless steel cold-rolled steel strip produced according to the present invention has a significantly superior surface gloss as compared with the steel strip produced by the conventional method. In particular, in the case of rolling using a large-diameter work roll such as a cold tandem mill, the surface gloss is equal to or better than that of rolling using a small-diameter work roll such as a Sendzimir mill, which has heretofore been impossible to reach.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eisuke Kawasumi 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Inside the Chiba Works (72) Inventor Takashi Akazawa 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Chiba Works, Ltd. (56) References JP-A-4-4904 (JP, A) JP-A-61-46307 (JP, A) JP-B-6-71604 (JP, B2) JP-B-3-34406 ( JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B21B 3/02 B21B 1/22 B21B 1/28 B21B 27/00

Claims (3)

(57) [Claims] When a stainless steel strip is rolled using a cold tandem mill and manufactured, at least a work roll made of a WC alloy is used for a first stand and / or a final stand, and a work roll diameter is φ400 m in the final stand.
A method for producing a high-gloss stainless steel strip, comprising rolling using a work roll having a diameter of 150 mm or less and a diameter of 150 mm or more. 2. When rolling a stainless steel strip using a cold tandem mill, a work roll made of a WC alloy is used for at least a first stand and / or a final stand, and the average roughness is Ra2 in the first stand. .50μm
Hereinafter, rolling is performed on a work roll having a surface roughness of 0.50 μm or more, and after the second stand, rolling is performed on a work roll having a surface roughness of not more than the average roughness of the work roll of the stand immediately before the stand. A method for producing a high-gloss stainless steel strip, comprising rolling at a final stand with a work roll having a surface roughness of Ra 0.15 μm or less and 0.05 μm or more. 3. The method for producing a high-gloss stainless steel strip according to claim 1, wherein the work roll made of the WC alloy is provided with a roll outer layer made of a WC alloy having a thickness of 5 mm or more. .