JP2019122997A - Metal plate and manufacturing method thereof - Google Patents

Abstract

To provide a metal plate small in roughness and low in Rsk and a manufacturing method thereof.SOLUTION: A manufacturing method of a steel plate sets rolling of a first stand as wet rolling, by setting a rolling load per unit width of the first stand to 0.8 tonf/mm or more, and setting a rolling load per unit width of a second stand to 0.3 tonf/mm or less, by respectively using a double roll of 1.4 μmRa or more in arithmetic average roughness and 250 or more in PPI for a work roll of the first stand and a bright roll of 0.5 μmRa or less in arithmetic average roughness for a work roll of the second stand, by executing the rolling by the stand number of two stands, when applying temper rolling to a steel plate after cold rolling.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a metal plate, in particular, a metal plate used for steel plates for cans, steel plates for automobiles, etc., and a method of manufacturing the same.

  For example, a cold rolled steel sheet is manufactured through cold rolling, annealing, and temper rolling of a hot rolled steel sheet. The temper rolling performed after annealing is performed for the purpose of adjusting the hardness of the steel plate and adjusting the surface roughness by the elongation (reduction) given to the steel plate in addition to reducing the steel plate to a desired thickness. In general, in temper rolling, dry temper rolling without a lubricant is often performed in consideration of the transferability of the surface roughness. However, in recent years, wet temper rolling, in which temper rolling is performed while spraying a lubricant onto a steel plate to prevent foreign matter from adhering to the roll, is increasing.

  From the viewpoint of transfer of surface roughness, it is known that in wet temper rolling, the transferability of the work roll surface to the steel plate is deteriorated due to the cushioning effect of the lubricant. Moreover, since the lubrication of the interface between the steel plate and the work roll is improved by the application of the lubricant, the load required for achieving the same elongation decreases, and as a result, the surface pressure on the steel plate decreases, It is known that the transferability is reduced.

  On the other hand, the surface of a cold-rolled steel sheet is controlled for parameters to ensure adhesion when using surface treatment such as lamination and painting, and to improve surface function in the case of steel sheet used without painting. necessary. Therefore, in general, the rolling conditions are determined so as to suppress the values of arithmetic mean roughness Ra (hereinafter also referred to as roughness) and PPI among the roughness parameters within a certain range. Conventionally, as a method of controlling the skewness Rsk of the roughness curve of the steel sheet surface, a method of performing surface adjustment of dull rolls such that Rsk after temper rolling falls within an appropriate range as disclosed in Patent Documents 1 and 2 is disclosed .

Patent No. 3052506 Unexamined-Japanese-Patent No. 5-237518

  However, the method shown in Patent Document 1 corresponds to the case where temper rolling is performed only with the dull roll 1 stand, and only shows a method of controlling the value of Rsk to a high value. Is not applicable.

  The method described in Patent Document 2 is a method for increasing the Rsk of a steel plate, and can not be applied for the same reason as Patent Document 1.

  This invention is made in view of the said subject, Comprising: It aims at providing a metal plate with small roughness and low Rsk, and its manufacturing method.

  The present inventors have intensively studied to solve the above problems. As a result, the following were found. In addition, in the following, a steel plate is mentioned as an example and demonstrated as a metal plate.

  As mentioned above, the conventionally known control method of Rsk in temper rolling was only the method of controlling the roughness of dull roll used for working rolls and processing method in temper rolling with only one stand. . In this method, in addition to the fact that Rsk can not be kept low, Ra of the steel plate rises as transfer of dull rolls is advanced, and it has been impossible to cope with low roughness.

  Therefore, the inventors examined a method for not increasing Ra of the steel plate while reducing Rsk. As a result, it was found that Rsk can be reduced by forming many small recesses on the surface of the steel plate. On the other hand, it was also found that if the number of large recesses is too large, Rsk will increase. In addition, it was also found that Ra can be reduced by performing temper rolling on multiple stands and using a bright roll for the second and subsequent stands by rolling experiments.

  As a result of the above investigations, in the present invention, as shown in FIG. 1, rolling is performed using a dull roll at the first stand to make many recesses, and rolling is performed using a bright roll at the second stand and thereafter. The basic technical idea is to gradually reduce the surface of the steel plate by gradually reducing it.

The gist of the present invention is as follows.
[1] A metal sheet characterized in that the arithmetic mean roughness of the steel sheet surface is 0.4 μm Ra or less and the skewness Rsk is 0.2 or less on at least one side.
[2] In the method of producing a metal plate according to the above [1], when tempering rolling is performed on the cold-rolled metal plate, the tempering rolling is performed with the number of stands of two stands; A dull roll with an arithmetic average roughness of 1.4 μm Ra or more and a PPI of 250 or more as the work roll on the stand, and a bright roll with an arithmetic mean roughness of 0.5 μm Ra or less for the work roll on the second stand, respectively, the unit of the first stand A manufacturing method of a metal plate characterized in that a rolling load per width is 0.8 tonf / mm or more, a rolling load per unit width of the second stand is 0.3 tonf / mm or less, and rolling of the first stand is wet rolling. .
[3] In the method of producing a metal plate according to the above [1], when the temper rolling is performed on the cold-rolled metal plate, the temper rolling is performed with three or more stands. Dull roll with an arithmetic mean roughness of 1.4 μm Ra or more and PPI of 200 or more on the first stand work roll, bright roll with an arithmetic mean roughness of 0.5 μm Ra or less on the second stand work roll, the third work roll Use a bright roll with an arithmetic mean roughness of 0.5 μm Ra or less, and set the rolling load per unit width at the first stand to 0.8 tonf / mm or more, and the rolling load per unit width at the second stand to 0.3 tonf / mm or less, A method of manufacturing a metal plate, wherein rolling of the first stand is wet rolling.
[4] The method of producing a metal plate according to the above [2] or [3], wherein rolling of all the stands is wet rolling.
[5] The method for producing a metal plate according to the above [1], wherein, when tempering rolling is performed on the cold-rolled metal plate, the tempering rolling is performed with two or more stands. Using dull rolls with an arithmetic average roughness of 1.0 μm Ra or more for the first stand work roll and bright rolls with an arithmetic average roughness of 0.5 μm Ra or less for the second stand work roll, rolling per unit width of the first stand A method of manufacturing a metal sheet, wherein a load is 0.8 tonf / mm or more, a rolling load per unit width of the second stand is 0.3 tonf / mm or less, and rolling of the first stand is dry rolling.
[6] In the method of manufacturing a metal plate according to the above [1], when the temper rolling is performed on the cold-rolled metal plate, the temper rolling is performed with three or more stands. Dull roll with an arithmetic mean roughness of 1.0 μm Ra or more on the first stand work roll, bright roll with an arithmetic mean roughness of 0.5 μm Ra or less on the second stand work roll, arithmetic mean roughness on the third stand work roll The rolling load per unit width of the first stand is 0.8 tonf / mm or more, the rolling load per unit width of the second stand is 0.3 tonf / mm or less, using the bright rolls of 0.5 μm Ra or less, and the first roll rolling A method of manufacturing a metal plate, characterized in that dry rolling is used.
[7] The method for producing a metal plate according to the above [5] or [6], wherein the work roll of the first stand has a PPI of 120 or more.
[8] The method of manufacturing a metal plate according to any one of the above [5] to [7], wherein the rolling after the second stand is wet rolling.

According to the present invention, a metal plate having a small roughness and a low Rsk can be obtained.
Since the metal plate of the present invention has a small roughness and a low Rsk, whitening can be prevented when the metal plate of the present invention is used as, for example, a laminated steel sheet.

FIG. 1: is a schematic diagram which shows the cross-sectional shape of the steel plate after rolling in each stand.

  The metal plate of the present invention has an arithmetic average roughness of 0.4 μm Ra or less and a skewness Rsk of 0.2 or less at least on one side. And such a metal plate can be manufactured by performing temper rolling by any one of the following methods, when manufacturing through the process of hot rolling, cold rolling, annealing, and temper rolling. .

Manufacturing method 1
When performing temper rolling on a steel plate after cold rolling, when rolling with the number of stands of 2 stands, dull rolls with an arithmetic average roughness of 1.4 μm Ra or more and PPI of 250 or more on the first stand work roll Use a bright roll with an arithmetic average roughness of 0.5 μmRa or less for the second stand work roll, and use a rolling load of 0.8 tonf / mm or more per unit width of the first stand, and a rolling load per unit width of the second stand Is 0.3 tonf / mm or less, and rolling of the first stand is wet rolling.
When rolling is performed with three or more stands in Production method 1, the dull roll with an arithmetic average roughness of 1.4 μm Ra or more and PPI of 200 or more on the first work roll is an arithmetic average on the second work roll Use a bright roll with a roughness of 0.5 μm Ra or less, and a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the third work roll, and use a rolling load of 0.8 ton f / mm or more per unit width for the first stand. The rolling load per unit width of the stand is 0.3 tonf / mm or less, and the rolling of the first stand is wet rolling. Preferably, a dull roll having a PPI of 250 or more is used for the work roll of the first stand. Preferably, the rolling load per unit width of the third stand is 0.3 tonf / mm or less. Moreover, it is preferable that rolling of all the stands is wet rolling. In the fourth and subsequent stands, conditions similar to those of the second stand are preferable with respect to the arithmetic average roughness of the work roll, the rolling load per unit width, and the like. That is, after the fourth stand, it is preferable to use a bright roll having an arithmetic average roughness of 0.5 μm Ra or less as the work roll, and to set a rolling load per unit width of 0.3 tonf / mm or less.

Manufacturing method 2
When temper rolling is applied to a steel plate after cold rolling, rolling is performed with two or more stands, and a dull roll with an arithmetic average roughness of 1.0 μm Ra or more is used as the first stand work roll, and the second stand Use a bright roll with an arithmetic average roughness of 0.5 μmRa or less for the work roll, and use a rolling load of 0.8 tonf / mm or more per unit width at the first stand, and 0.3 tonf / mm of rolling load per unit width at the second stand The rolling of the first stand is dry rolling as follows.
When rolling is performed with three or more stands in Production method 2, the third stand uses a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the work roll, and the rolling load per unit width is 0.3 tonf / mm or less It is preferable to In addition, it is preferable that the work roll of the first stand has a PPI of 120 or more. Moreover, it is preferable that rolling after 2nd stand is wet rolling. In the fourth and subsequent stands, conditions similar to those of the second stand are preferable with respect to the arithmetic average roughness of the work roll, the rolling load per unit width, and the like. That is, after the fourth stand, it is preferable to use a bright roll having an arithmetic average roughness of 0.5 μm Ra or less as the work roll, and to set a rolling load per unit width of 0.3 tonf / mm or less.

The number of the temper rolling stands: two or more stands In the temper rolling process of the present invention, two or more rolling stands are used. Generally, in one-stand temper rolling, dull rolls are used to adjust the strength of the material by rolling reduction and to correct the flatness of the material. On the other hand, when a variety of steel plate roughness and appearance are required, rolling of one stand with dull rolls can not achieve balance between strength adjustment and roughness adjustment, and roll replacement must be performed frequently. Therefore, it should be two or more stands that can be adjusted by the balance of the load.

In 1st stand work roll manufacturing method 1, the 1st stand rolling is performed by wet rolling, and when rolling with the number of 2 stand stands, arithmetic mean roughness is 1.4 μm Ra or more on the 1st stand work roll, Use a dull roll with a PPI of 250 or more. When rolling with three or more stands, a dull roll with an arithmetic average roughness of 1.4 μm Ra or more and a PPI of 200 or more is used as the work roll of the first stand.
In the manufacturing method 2, the rolling of the first stand is performed by dry rolling, and a dull roll having an arithmetic average roughness of 1.0 μm Ra or more is used as the work roll of the first stand.
By using a dull roll whose surface is controlled at the first stand, small recesses can be formed on the steel sheet surface. At this time, the concave portion to be formed needs to be deep enough not to be completely eliminated by rolling by the second bright roll. Therefore, at the first stand, it is necessary to perform dry temper rolling having a large transfer rate or to perform wet rolling using a dull roll having a large roughness.

  However, in general, when the roughness is large, the PPI of the roll is small and the concave portion generated in the steel plate is large, so the reduction effect of Rsk is limited. Therefore, when wet rolling is performed at the first stand, it is preferable to use electric discharge machining or laser machining in which PPI is larger than the generally used shot blast as a method for dull machining of work rolls.

  From the above, in the case of wet rolling, the arithmetic average roughness of the work roll of the first stand is set to 1.4 μmRa or more, preferably 1.7 μmRa or more, from the viewpoint of forming small recesses on the steel sheet surface. On the other hand, the upper limit is preferably 2.5 μm Ra or less because a recess having a too large depth may remain and the Rsk may be increased.

  In the case of dry rolling, the arithmetic mean roughness of the work roll of the first stand is 1.0 μm Ra or more, preferably 1.3 μm Ra or more, in order to form small recesses on the steel sheet surface. On the other hand, the upper limit is preferably 2.0 μm Ra or less for the same reason as described above.

  In the case of wet rolling, PPI of the first work roll is 250 or more when rolling with 2 stands, 200 or more when rolling with 3 or more stands, preferably 250 or more I assume. By setting PPI to the above-mentioned value, since the recesses are distributed in a small size, it is possible to reduce Rsk.

  In addition, wet rolling is a method of rolling, for example, after making a lubricant adhere to a steel plate by means, such as application | coating and spraying. Dry rolling is a method of rolling without using a lubricant.

In the work roll manufacturing method 1 of the second stand, the second stand is preferably performed by wet rolling, and a bright roll having an arithmetic average roughness of 0.5 μm Ra or less is used as the second stand work roll.
In the production method 2, the second stand is preferably performed by wet rolling, and a bright roll having an arithmetic average roughness of 0.5 μm Ra or less is used as a work roll of the second stand.

  In the second stand, if the roughness is made as large as the depth of the recess, the reduction effect of Rsk can not be obtained. Therefore, the surface roughness of the roll used in the second stand is set to a value sufficiently smaller than the depth of the recess, specifically, 0.5 μm Ra or less.

When rolling with the number of stands of 3rd stand or more work rolls, use a bright roll with an arithmetic average roughness of 0.5 μmRa or less as the third stand work roll in any of manufacturing method 1 and manufacturing method 2 Is preferred. By using a bright roll having an arithmetic average roughness of 0.5 μm Ra or less for the third stand, the concave portions attached to the first stand remain until after rolling. Further, by suppressing the roughness transfer by the bright roll, it is possible to suppress the rise of Rsk by the bright roll.

Rolling Load for First Stand First, the rolling load per unit width of the first stand is 0.8 tonf / mm or more for both of the production methods 1 and 2. If the load is less than 0.8 tonf / mm, sufficient recesses are not formed on the steel sheet surface. On the other hand, 1.2 tonf / mm or less is preferable from the reason of the deterioration of the steel plate shape by rolling.

Rolling load for the second stand The rolling load per unit width for the second stand is 0.3 tonf / mm or less for both of the production methods 1 and 2.
If the rolling load per unit width at the second stand exceeds 0.3 tonf / mm, the concave portion created at the first stand collapses, resulting in an increase in Rsk. Therefore, the rolling load per unit width of the second stand should be 0.3 tonf / mm or less. On the other hand, 0.1 tonf / mm or more is preferable from the reason of adjustment of an elongation rate, and the controllability of steel plate roughness.

Rolling Load for the Third Stand The rolling load per unit width at the third stand is preferably 0.3 tonf / mm or less for the same reason as the rolling load for the second stand in both of the production methods 1 and 2. More preferably, they are 0.1 ton f / mm or more and 0.3 tonf / mm or less.

  From the above, in the present invention, since the depression remains in the steel sheet after temper rolling, Rsk decreases, and Ra of the steel sheet can be controlled by adjusting the roll roughness after the second stand.

  Prior to temper rolling of the steel sheet, hot rolling, pickling and cold rolling can be performed.

  In the hot rolling step, steel adjusted to a predetermined component composition is melted by a converter or the like and made into a slab by a continuous casting method or the like. The slabs used are preferably produced by continuous casting to prevent macrosegregation of the components, but may be produced by ingot casting or thin slab casting. In addition, after the slab is manufactured, it is cooled to room temperature and then reheated and added to the conventional method, and then it is not cooled to room temperature, but is inserted into the furnace as a hot piece or after slight heat retention Energy saving processes such as direct feed rolling and direct rolling, which are immediately rolled, can also be applied without problems.

  The finish rolling temperature in the hot rolling step is preferably 850 ° C. or more from the viewpoint of the stability of the rolling load. On the other hand, raising the finish rolling temperature more than necessary may make it difficult to manufacture thin steel plates. Specifically, the finish rolling temperature is preferably in the temperature range of 850 to 960 ° C. The upper limit of the coiling temperature is not particularly limited, but if the coiling temperature is excessively high, the scale thickness of the steel sheet surface becomes thick, and the descaling property in the acid washing in the acid washing step becomes worse. On the other hand, the lower limit of the coiling temperature is not particularly limited, but if the coiling temperature is excessively reduced, the strength of the hot rolled steel sheet obtained in the hot rolling process increases and the rolling load in the primary cold rolling process increases. The winding temperature is preferably 500 ° C. or higher because control becomes difficult.

  The pickling step is a step of removing the oxide scale on the surface of the hot rolled steel sheet obtained in the hot rolling step by pickling. The pickling conditions are not particularly limited, and may be set as appropriate. Also, instead of pickling, a method such as mechanical removal may be used.

  The primary cold rolling step is a step of subjecting the pickling plate after the pickling step to cold rolling. The cold rolling conditions are not particularly limited, and for example, the conditions such as the rolling reduction may be determined from the viewpoint of the desired plate thickness and the like.

  By the above, the metal plate of the present invention is obtained. In order to further obtain the effects of the present invention, the thickness of the present invention is preferably 0.1 to 0.6 mm.

  The metal plate of the present invention manufactured in the above manner has an arithmetic average roughness of 0.4 μm Ra or less and a skewness Rsk of 0.2 or less on at least one surface. Arithmetic mean roughness: Ra is 0.4 μm Ra or less, and skewness: Rsk is 0.2 or less, air bubbles are less involved when laminating, and it becomes possible to prevent whitening of the laminate plate.

  In the present invention, the metal plate is a steel plate, a copper plate, an aluminum plate or the like.

A rolling mill consisting of two stands was used. A load of 780 tonf (a unit width load of 0.82 tonf / mm) was applied to the first stand using a 500 500 dull roll, and rolling was performed using a 500 500 bright roll at the second stand while changing the load and roll roughness. The test material was a low carbon steel (cold-rolled steel plate) with a width of 950 mm and a thickness of 0.23 mm, the tension value between the stands was adjusted, and temper rolling was performed so that the elongation rate was 2.0% or less . Moreover, Rsk of the steel plate after rolling was measured 5 times, and the average value was computed.
The laser processing machine was processed using a copper electrode using a product made by Sarclad. The current application time was 8 μsec, the off time was 14 μsec, the current value at 1.3 μmRa was 4 A, and the current value at 1.7 μmRa was 6 A. (Laser level will be added)
Rsk was measured using a contact-type roughness meter specified in JIS, and the measurement length was 5 mm. Those with a value of Rsk exceeding 0.20 were rated as x, those with 0 to 0.20 as Δ, and those with less than 0 as 0.
The results obtained by the above are shown in Table 1.

In the example of the present invention, a metal plate having a small roughness and a low Rsk can be obtained.
The Rsk of the steel plate can be reduced by rolling at a low load at the second stand and reducing the roll roughness by using a dry or rough dull roll that can generate a deeper recess at the first stand. It was shown that

Claims (8)

  A metal plate characterized in that the arithmetic mean roughness of the steel plate surface is 0.4 μm Ra or less and the skewness Rsk is 0.2 or less on at least one side. The method of manufacturing a metal plate according to claim 1, wherein the cold rolled metal plate is subjected to temper rolling.
Carry out the above temper rolling with the number of stands of 2 stands,
Darulole with an arithmetic average roughness of 1.4 μm Ra or more and PPI of 250 or more on the first-stand work roll,
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the second stand work roll,
The rolling load per unit width at the first stand is 0.8tonf / mm or more,
The rolling load per unit width at the second stand is 0.3 tonf / mm or less,
A method of manufacturing a metal plate, wherein rolling of the first stand is wet rolling. The method of manufacturing a metal plate according to claim 1, wherein the cold rolled metal plate is subjected to temper rolling.
Carry out the above temper rolling with the number of stands of 3 stands or more,
Darulole with an arithmetic average roughness of 1.4 μm Ra or more and a PPI of 200 or more on the first work roll
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less as the second work roll
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the third stand work roll,
The rolling load per unit width at the first stand is 0.8tonf / mm or more,
The rolling load per unit width at the second stand is 0.3 tonf / mm or less,
A method of manufacturing a metal plate, wherein rolling of the first stand is wet rolling.   The method of manufacturing a metal plate according to claim 2 or 3, wherein rolling of all the stands is wet rolling. The method of manufacturing a metal plate according to claim 1, wherein the cold rolled metal plate is subjected to temper rolling.
Carry out the above temper rolling with the number of stands of 2 stands or more,
Dull roll with an arithmetic average roughness of 1.0 μm Ra or more, on the first work roll
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the second stand work roll,
The rolling load per unit width at the first stand is 0.8tonf / mm or more,
The rolling load per unit width at the second stand is 0.3 tonf / mm or less,
The manufacturing method of the metal plate characterized by making rolling of the 1st stand dry rolling. The method of manufacturing a metal plate according to claim 1, wherein the cold rolled metal plate is subjected to temper rolling.
Carry out the above temper rolling with the number of stands of 3 stands or more,
Dull roll with an arithmetic average roughness of 1.0 μm Ra or more, on the first work roll
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less as the second work roll
Use a bright roll with an arithmetic average roughness of 0.5 μm Ra or less for the third stand work roll,
The rolling load per unit width at the first stand is 0.8tonf / mm or more,
The rolling load per unit width at the second stand is 0.3 tonf / mm or less,
The manufacturing method of the metal plate characterized by making rolling of the 1st stand dry rolling.   7. The method according to claim 5, wherein the first work roll has a PPI of 120 or more.   The method of manufacturing a metal plate according to any one of claims 5 to 7, wherein the rolling after the second stand is wet rolling.