JPWO2018092898A1 - Steel sheet passing method, steel sheet manufacturing equipment and steel sheet manufacturing method - Google Patents

Abstract

A steel sheet passing method capable of reducing the production cost of a product by suppressing the occurrence of quality abnormality of the surface of a steel sheet, particularly a thin sheet, and prolonging the roll replacement cycle, the production equipment for thin steel sheet, and steel sheet Provide a manufacturing method of This is a method of passing a steel plate using a steel plate contact roll in which a dimple sprayed layer is formed on the surface and the Rpk of the surface is 2 μm to 12 μm.

Description

  The present invention relates to a steel sheet passing method, steel sheet manufacturing equipment, and steel sheet manufacturing method capable of prolonging the roll replacement period while suppressing the occurrence of quality abnormalities on the steel sheet surface.

  In the steel sheet manufacturing process, various treatments are performed while the steel sheet is continuously conveyed by various rolls. In the process of manufacturing a thin steel sheet (for example, a steel sheet for tin plating) required to have a high quality appearance in particular, it is important not to wrinkle the surface and not to generate gloss unevenness on the surface. Uneven gloss is a defect caused by the appearance of wrinkles on the surface of the steel plate by the rolls in contact with the steel plate, and the wrinkles look different from other portions depending on how light is hit. Fine projections on the surface of the roll are pressed against the steel plate to cause 疵 (scratch 疵) on the surface of the steel plate, contact with the steel plate in a state where the roll is worn, slip, and wrinkling (scratch) on the steel surface Cause uneven gloss. In particular, at the time of production of a thin steel plate, it is desirable to reduce unevenness on the surface of the roll in contact with the steel plate so that no wrinkles are applied to the surface of the steel plate.

In the manufacturing process of a thin steel plate, since the steel plate is conveyed at high speed, wear of the roll in contact with the steel plate is quickened. If the roll remains in the worn state, there is a concern that the worn portion causes the steel plate to slip relative to the roll, causes the above-mentioned uneven gloss, and causes the steel plate to meander. Therefore, in the manufacturing equipment of a thin steel plate, roll replacement by a short cycle is needed, and it is one of the factors which raise the manufacturing cost of a steel plate.
In particular, when a thin steel plate having a yield stress of 20 kgf / mm ² (196 MPa) or more is continuously transported in a dry state in which a liquid such as oil does not adhere to the surface, the steel plate having the above strength has rolls and liquid. There is also a problem that the abrasion of the roll is significantly increased by direct contact without causing the abrasion of the roll to be greater than when the steel plate and the roll contact through the liquid (for example, a roll in a plating bath of electrozinc etc.) It was

  As described above, in the manufacturing process of thin steel sheet, particularly in the manufacturing process of a steel sheet for tin plating, manufacturing cost is reduced by lengthening the roll replacement cycle while suppressing occurrence of quality abnormality on the steel sheet surface. Is required.

  As a method of reducing the quality abnormality in the steel plate surface, in patent document 1, the method of using the roll which gave dimple processing as a rolling roll is mentioned. The dimpled roll has minute dimple-like depressions on the surface. The dimpled roll has the advantage that the fine convex and concave portions on the surface are rounded compared to the shot-rolled roll, so that fine wrinkles are less likely to be formed on the steel sheet surface and uneven gloss of the steel sheet is less likely to occur. . However, the document disclosed in Patent Document 1 is a technique of applying dimple processing and grinding to a roll base, and has a disadvantage that roughness is easily reduced and roll life is short.

  Patent Document 2 discloses a roll in which plating formed on the surface is subjected to dimple processing. However, a roll obtained by dimple processing a plated film has a disadvantage that the roughness is likely to be reduced and the roll life is short.

  As a method of extending the roll replacement period, as shown in Patent Document 3, there is a method of using a thermal spray roll in which the surface of the roll is sprayed with tungsten carbide or the like. The thermal spray roll is less likely to cause a reduction in roughness than a chromium-plated roll, and has the advantage of being able to extend the roll replacement cycle. On the other hand, the thermal spray roll has a disadvantage that it is easy to cause quality abnormality such as gloss unevenness on the surface of the steel plate. Once a quality abnormality occurs, it is necessary to stop the manufacturing equipment and carry out surface cleaning of the roll, which causes a problem of a reduction in yield.

JP 2007-275978 A JP, 2005-307326, A Japanese Patent Application Publication No. 2008-001927

The present invention has been conceived in view of the above problems, and suppresses the occurrence of quality abnormalities on the surface of a steel plate, particularly a thin plate, and reduces the manufacturing cost of the product by prolonging the roll replacement cycle. It is an object of the present invention to provide a method of passing a steel plate, a production facility of a thin steel plate, and a method of manufacturing a steel plate.
That is, according to the present invention, in the case of continuously transporting a thin steel sheet in a dry state in which no liquid such as oil is attached to the surface, or unavoidably in a continuous processing line of steel sheets such as continuous annealing described later. Even when acceleration or deceleration of the generated line speed (conveying speed of the steel plate) occurs, the thin steel plate does not slip with respect to the roll, gloss unevenness is not generated, and the roll replacement cycle is further lengthened. The present invention relates to a possible method of passing a steel plate, a production facility of a thin steel plate, and a method of producing a steel plate.

The means of the present invention are as follows.
[1] A sheet passing method of a steel sheet using a steel sheet contact roll in which a dimple sprayed layer is formed on the surface and Rpk of the surface is 2 μm to 12 μm.
[2] The steel sheet passing method according to the above [1], wherein the hardness (Hv) of the sprayed layer is 1200 to 2000.
[3] The steel sheet passing method according to the above [1] or [2], wherein the hardness (Hs) of the material of the base of the sprayed layer is 70 to 85.
[4] The steel sheet passing method according to any one of the above [1] to [3], wherein the outer diameter of the steel sheet contact roll is 250 mm to 1600 mm.
[5] The steel sheet having a thickness of 0.13 mm to 2.7 mm is passed through the steel sheet contact roll under the condition that a unit tension of 1 to ²⁰ kgf / mm ² is applied [1] to [4] The passing method of the steel plate in any one of.
[6] A manufacturing method of a steel plate which manufactures a steel plate using a passing method of a steel plate in any one of the above-mentioned [1]-[5].
[7] A manufacturing facility of a thin steel plate provided with a steel plate contact roll having a dimple sprayed layer formed on the surface and a surface Rpk of 2 μm to 12 μm.
[8] The apparatus for producing a thin steel sheet according to the above [7], wherein the hardness (Hv) of the thermal sprayed layer is 1200 to 2000.
[9] The apparatus for producing a thin steel plate according to the above [7] or [8], wherein the hardness (Hs) of the material of the base of the thermal spray layer is 70 to 85.
[10] The apparatus for manufacturing a thin plate according to any one of the above [7] to [9], wherein the outer diameter of the steel plate contact roll is 250 mm to 1600 mm.
[11] The above-mentioned [7] which can pass the steel plate having a thickness of 0.13 mm to 2.7 mm with the steel plate contact roll under the condition that a unit tension of 1 to ²⁰ kgf / mm ² is applied. The manufacturing equipment of the steel plate in any one of [10].

  According to the present invention, it is possible to achieve both reduction in quality abnormality of the steel plate and life extension of the steel plate contact roll at the time of passing the steel plate. Furthermore, since abnormal quality of the steel plate can be effectively eliminated even under severe conditions where the steel plate and the roll are in direct contact with each other, the thin steel plate is continuously transported in a dry state in which liquid such as oil is not adhered to the surface Alternatively, the present invention is more effective when there is acceleration or deceleration of the line speed which inevitably occurs in the continuous processing line of steel sheets such as continuous annealing.

FIG. 1 is a flow chart showing a continuous annealing facility. FIG. 2 is a side view showing an example of a steel plate contact roll. FIG. 3 is a side view showing the application site of the bridle roll. FIG. 4 is a graph showing the time-dependent change of R pk of the roll surface in the inventive example and the comparative example. FIG. 5 is a graph showing the relationship between Rpk on the roll surface and the presence or absence of slip and the presence or absence of uneven gloss. FIG. 6 is a cross-sectional view for explaining an example of a schematic configuration of a steel plate contact roll.

  First, continuous annealing equipment shown in FIG. 1 will be described as an example of manufacturing equipment for thin steel plates.

  The physical properties of the cold rolled steel sheet are adjusted in the continuous annealing line. Specifically, on the entrance side of the continuous annealing furnace, the cold rolled coil is unwound by the payoff reel, and the thin steel plate is continuously passed while being welded by the welding machine. The thin steel sheet is subjected to pretreatment such as surface cleaning, and after being tensioned by a tension leveler and an inlet looper, enters a continuous annealing furnace.

  In the continuous annealing furnace, the thin steel plates are heated in the preheating furnace and the heating furnace, and are maintained at a predetermined temperature in the soaking furnace, and then rapidly cooled in the GJ (gas jet) zone. Next, the annealing is completed by holding the steel sheet at a predetermined temperature in an OA (overaging) furnace and performing final cooling of the steel sheet by a quenching zone and water cooling.

  The annealed thin steel sheet is adjusted in tension by the outlet looper and then adjusted in surface quality by the temper mill, and then wound on a tension reel. In addition, although illustration is abbreviate | omitted about the detail, various plating processes (for example, galvanization process) are performed between a continuous annealing furnace and a tension reel, or various plating processes (for example, tin plating) in the installation of the next process. A plated steel sheet is manufactured by performing a process.

In such a steel plate manufacturing facility, a large number of steel plate contact rolls are provided. A steel plate contact roll is a roll which has the function to plate a steel plate by contacting with a steel plate in the outer surface. As a specific example of the steel plate contact roll, as shown in FIG. 2 (a), a support roll that assists sheet passing in contact with the upper surface or the lower surface of the steel plate, as shown in FIG. 2 (b) A deflector roll that changes the direction, a looper roll in a looper of a manufacturing facility (not shown), and the like can be mentioned. The properties required for these steel plate contact rolls include three characteristics: excellent durability, no generation of uneven gloss on the surface of the steel plate, and, in particular, no generation of slippage of the steel plate passing through. .
In the present invention, in particular, when manufacturing a steel plate, an acceleration / deceleration portion where the speed of passing rapidly changes (when processing the steel plate continuously, when the leading coil and the trailing coil are connected, decelerating temporarily) Is effective in preventing the occurrence of slippage). For example, in the acceleration part, when accelerating from 500 mpm to 1000 mpm in 3 to 5 minutes, slip is likely to occur. In the reduction gear, slippage is likely to occur when decelerating from 800 mpm to 50 mpm in 3 to 5 minutes. That is, the present invention can effectively prevent the slip of the steel plate at the time of acceleration and deceleration.
As described above, according to the present invention, even when the thin steel sheet is continuously transported in a dry state where no liquid such as oil is attached to the surface, it is inevitable at the continuous processing line of the steel sheet such as continuous annealing described above. Even when acceleration or deceleration of the line speed (conveying speed of the steel sheet) occurs, the thin steel sheet does not slip against the roll, and uneven gloss is not generated, and the roll replacement cycle is extended. The present invention relates to a method of passing a steel plate, a manufacturing equipment of a thin steel plate, and a method of manufacturing a steel plate.

  As a specific example, FIG. 6 shows a cross-sectional view of a steel plate contact roll. In this invention, the durability of a roll can be improved by using the roll which formed the dimple spray layer on the surface as a steel plate contact roll. The dimple sprayed layer refers to a sprayed layer in which the dimple shape is formed. Specifically, a thermal spray material (a thermal spray agent) is sprayed on the surface of the roll, and the formed thermal spray layer is subjected to shot processing, and if necessary, fine dimple-like depressions are appropriately formed by surface adjustment described later. By doing this, the dimple sprayed layer intended in the present invention is obtained. The thermal spray material is preferably a material superior in wear resistance to chromium plating, and examples thereof include tungsten carbide and the like. For the formation of the thermal spray layer, for example, a high velocity oxygen fuel (HVOF) spray gun, a D-Gun (detonation gun), a plasma spray, or the like can be used. In addition, the number density, the size, and the like of the depressions (dimples) on the roll surface are not particularly limited as long as the effects of the present invention are exhibited.

  In the present invention, it has been found that the most preferable roughness parameter from the viewpoint of slip and gloss unevenness of a steel sheet is Rpk. That is, in the present invention, by setting Rpk of the roll surface to 2 μm to 12 μm, slippage, meandering, etc. can be suppressed and sheet passing can be stabilized and generation of surface defects (glossy unevenness) of the steel plate is prevented. be able to. For example, when R pk is less than 2 μm, it is difficult for the thin steel sheet to slip against the roll and to stably pass at high speed. If Rpk is more than 12 μm, the unevenness of the roll surface is transferred to the steel sheet surface, or the unevenness of the roll surface causes scratch marks on the steel sheet surface, and surface defects (uneven glossiness) are easily generated in the steel sheet. When a surface defect occurs in the steel plate, once the manufacturing equipment of the steel plate is stopped, adjustment work such as surface maintenance of the steel plate contact roll is required, which increases the manufacturing cost. Preferred R pk from the viewpoint of slip is 4 μm or more. A further preferable Rpk from the viewpoint of slip is 4.1 μm or more. Moreover, preferable Rpk from the viewpoint of gloss unevenness is 10 μm or less.

  When adjusting Rpk of the roll surface to 2 μm to 12 μm, if the tip of the protruding peak portion of the convex portion formed by shot processing or the like after the formation of the sprayed layer is too sharp (protrusion degree is too large), Rpk Is over 12 μm. Therefore, it is important to make the surface adjustment so that the tip of such a protruding peak portion is not too sharp and to set Rpk within the range of 12 μm or less.

The above-mentioned surface conditioning is performed, for example, in order to make Rpk within the range of 12 μm or less when the tip of the protruding peak portion of the above-mentioned convex portion is too sharp and Rpk exceeds 12 μm. It is. For example, surface grinding is performed. At this time, it is preferable to reduce the roughness of the grinder to 220 # or more, to increase the surface pressure during grinding to 50 kgf / cm ² or more, and to reduce the feed rate during grinding to 100 mm / min or less. .

  Rpk is also referred to as protruding peak height or the like, and is an index for evaluating the number and amount of protruding portions having a large degree of protrusion on the surface. It is evaluated that the larger the Rpk is, the larger the number of convex portions having a large degree of protrusion (and / or the larger the amount of protrusion of the convex portions) on the surface of the roll. As Rpk, for example, the definition and measurement method in JIS (Japanese Industrial Standard) B 0671-2: 2002 can be adopted.

  Moreover, it is preferable that the surface hardness of the roll after thermal spraying for acquiring the effect of this invention is 70-95 in Hs. When the surface hardness of the roll after thermal spraying is 70 or more in Hs, the durability intended in the present invention can be sufficiently obtained. In addition, when the surface hardness of the roll after thermal spraying is Hs 95 or less, no cracking occurs in the roll (shell portion) at the time of formation of the subsequent sprayed layer, and uneven gloss of the steel sheet product does not occur, and further the roll life Can also be long. The surface hardness of the roll after spraying is more preferably 75 or more and 85 or less in Hs. Here, the surface hardness Hs of the roll is measured by contacting the surface of the roll with a Shore hardness tester. The surface hardness of the roll after thermal spraying is, as measured from the surface of the roll, the thickness of the thermal spray layer to be described later is as thin as 0.05 to 0.2 mm, so substantially the base of the thermal spray layer, ie before thermal spraying to be described later It is known that the value reflects the hardness of the material of the roll (the material of the shell portion). More preferably, as shown in Table 2, the roll material (the material of the shell portion) before thermal spraying is carbon steel such as SUJ2, SS400, S45C, STKM16A, etc.

In order to stably obtain the excellent durability of the present invention, that is, the effect of prolonging the roll replacement period, the surface of the hardness (Hs) of the material of the thermal spray layer (hereinafter, the surface of the roll (shell portion)) The hardness (Hs) is preferably 70-85. When the surface hardness (Hs) of the roll (shell portion) is 70 or more, the durability intended in the present invention can be sufficiently obtained. In addition, when the surface hardness (Hs) of the roll (shell portion) is 85 or less, no cracking occurs in the roll (shell portion) at the time of formation of the subsequent sprayed layer, and uneven gloss of the steel sheet product does not occur. The lifetime can also be extended. In addition, a shell part points out the cylindrical part of the roll trunk | drum shown in FIG. In the present invention, the base of the thermal spray layer means the surface of the above-mentioned shell part. More preferably, the material of the roll before thermal spraying (the material of the shell) is carbon steel such as SUJ2, SS400, S45C, STKM16A, etc., and induction hardening is performed on the shell described above, and the surface hardness of the roll (shell) It is desirable to make (Hs) a material of 70 to 85. The confirmation of controlling the material of the surface of the shell portion to 70 to 85 with Hs is performed by bringing the Shore hardness meter into contact with the surface of the shell portion and measuring after induction hardening of the shell portion described above. In addition, it is preferable to perform measurement of the surface hardness (Hs) of a roll (shell part) by one or more points, and when the number of measurements is two or more, an average process shall be performed. For example, a plurality of points may be measured in the roll cylinder length direction (width direction).
In addition, about the structure of a shell part, a hollow structure is preferable. With the hollow structure, the strength of the roll is secured by setting the thickness (t) of the shell portion to the size of t = D / 40 to D / 14 with respect to the roll outer diameter (D), and Inertia can be reduced to a level that can suppress the occurrence of slip and gloss unevenness in the acceleration / deceleration portion at the time of passing the sheet as intended in the present invention. Further, the structure of the bearing portion of the roll (the bearing portion in FIG. 6) is separately manufactured by a strength design that the roll can withstand in use.

  For the sprayed layer, the hardness (Hv) is preferably set to 1200 to 2000. When the hardness of the sprayed layer is Hv at 1200 or more, the function and effect of the present invention, that is, the function and effect when Rpk is in the range of 2 to 12 (the effect of preventing generation of uneven gloss and slip) is sufficiently obtained Can. In addition, when the hardness of the sprayed layer is Hv or less 2000, the surface of the roll is not too hard and becomes brittle, so the effects and advantages of the present invention can be sufficiently obtained. Therefore, the hardness (Hv) of the sprayed layer is preferably 1200 to 2000. More preferably, as an example shown in Table 3, as the thermal spray material, WC-12% Co, WC-20% CrC / 5% Ni + 22% Ni, Ti (C, N), WC-12% Co- There is 10% Cr etc. The reason for using these thermal spray materials is that it is easy to obtain 1200 to 2000 as the hardness (Hv) of the thermal spray layer. In the evaluation of the hardness (Hv) of the sprayed layer, a sample is taken from the sprayed layer formed by spraying the sprayed material, and the cross-section is polished so that the section of the sprayed layer can be observed. It evaluates by measuring by the maximum load which becomes the diagonal length of the indentation of 1/5 to 1/6 Vickers hardness. The hardness (Hv) obtained by this method was taken as the thermal sprayed layer hardness (Hv).

  The thickness of the sprayed layer (the thickness of the sprayed coating) is preferably 0.05 mm or more. Moreover, the preferable upper limit of the thickness of a sprayed coating is 0.2 mm or less.

When a thin steel plate (with a yield strength of 20 kgf / mm ² or more) is to be inserted, the sheet passing speed is increased, so that the wear of the steel plate contact roll is increased. In addition, when a high tension is applied to the steel plate, sheet passing abnormality such as slip is likely to occur in the steel plate contact roll. In the present invention, even when a thin steel sheet is passed with high tension, the durability of the roll can be improved, and the problem of sheet passing abnormality can be prevented. In addition, the steel plate of 0.13 mm-2.7 mm of plate thickness can be mentioned as an example of the thin steel plate in which the effect of this invention is acquired. Moreover, high tension depends on the thickness, shape, line speed, etc. of the thin steel sheet, but as an example, 1 to 1 in unit tension (tension per unit cross sectional area of the steel sheet) where the effect of the present invention can be obtained. A condition of 20 kgf / mm ² can be mentioned. The line speed is preferably 1200 mpm or less from the viewpoint of the abrasion resistance of the roll to which the present invention is applied. The lower limit is preferably 50 mpm or more from the viewpoint of the productivity of the steel plate.

  In addition, it is preferable that the outer diameter of the roll (it is also only called a "dimple roll") provided with the dimple thermal spray layer from which the effect of this invention is acquired is 250 mm-1600 mm. The outer diameter of the roll can be appropriately determined so that no warpage (plastic deformation) occurs in the steel sheet. The outer diameter of the roll refers to the diameter of the roll including the axial center of the roll to the dimple sprayed layer.

  The dimple roll can be applied to any roll that comes in contact with a steel plate (steel plate contact roll). For example, in thin steel manufacturing equipment as shown in FIG. 1, it may be applied to any one or more steel plate contact rolls. In particular, the bridle roll located on the entrance side or the exit side of the roller leveler in the tension leveler shown in FIG. It is preferable to apply a dimple roll. The bridle roll has a function of controlling the tension of the steel plate while holding the steel plate between the plurality of rolls. In the bridle roll, since the steel plate is passed while applying high tension, a passing failure such as slip is likely to occur. Therefore, by applying the dimple roll according to the present invention, it is possible to reliably prevent the problem of passing defects in the bridle roll. Although four bridle rolls shown in FIG. 3 are arranged, the number of rolls is not limited to these examples.

  As shown in FIG. 2 (b), in the case of a deflector roll having a large winding angle of the steel plate, there is a problem that it is particularly easy to apply wrinkles or the like to the surface of the steel plate. Therefore, applying the above-described dimple roll to such a deflector roll has the effect of reliably preventing uneven gloss.

  The manufacturing equipment of a thin steel plate means the equipment which performs various processing, passing the steel plate after cold-rolling continuously, as shown in FIG. For example, as a process performed in the manufacturing equipment of a thin steel plate, annealing treatment, plating treatment (and alloying treatment as needed), and chemical conversion treatment etc. are mentioned.

  By using the dimple roll according to the present invention, for example, steel plates for cans (such as tin-plated steel plates), cold rolled steel plates for automobiles and home appliances, hot-dip galvanized steel plates, etc. excellent in press formability and paintability are stabilized. It can be manufactured. Moreover, as for the strength level of a steel plate, TS (tensile strength) can be applied to 260 MPa-2000 MPa.

  The present invention is not limited to the configurations described in the embodiments to be described later, and includes other embodiments and modified embodiments which can be considered within the scope of the matters described in the claims.

Example 1
A dimple roll (roll surface hardness Hs 83 (average of four)) was applied to the bridle roll on the inlet side of the temper mill of the continuous annealing facility for tin-plated steel sheet shown in FIG. This Hs 83 is an average value of surface hardness Hs of four dimple rolls. The surface hardness Hs of each roll was measured at five points in the longitudinal direction of each roll, and the average value was taken as the measurement value of each roll. The bridle roll is used as a set of four as shown in FIG. 3A, but all four of these are used as dimple rolls. The applied plate thickness of the steel plate in the continuous annealing equipment was 0.15 mm to 0.6 mm. In addition, the yield strength of the plate thickness in the present Example 1 was 28-37 kgf / mm < ² >. The diameter of the dimple roll was 500 mm, and the unit tension was 4 to 10 kgf / mm ² . The line speed was 400-1150 mpm. The hardness Hv (average of four) of the sprayed layer was 1200, and the thickness (average of four) of the sprayed layer was 0.05 mm. Between six months, an acceleration unit accelerating from 400 mpm to 1150 mpm in 5 minutes and a decelerating unit decelerating from 1150 mpm to 50 mpm in 5 minutes were generated 15,000 times each. The Rpk (average of four) of the dimple roll used at the beginning of use was 8 μm, and the Rpk (average of four) of the dimple roll six months after use was examined (see the left side of FIG. 4). .

On the other hand, the same experiment as described above was performed using a roll in which a chromium plating film was dimpled as the same bridle roll. In addition, the hardness (Hv) of the chromium plating film was 1000. The thickness (average of 4) of the chromium plating film was 0.05 mm. The results are shown on the right of FIG. In FIG. 4, the results of the change with time of R pk show that four dimple rolls used as bridle rolls (compared after passing an arbitrary number selected from the range of the plate thickness of 0.15 mm to 0.6 mm) In the example, the Rpk average of all four normal rolls).
The initial Rpk (average of 4) was 8 μm, but the Rpk (average of 4) at 6 months after use decreased to 1.8 μm. Although the details will be described later in Example 2, the slip limit Rpk (Rpk value that is more likely to cause slip when Rpk decreases further) is 2 μm, and in the comparative example, the roll needs to be replaced. The Thus, it has been shown that the roll pk reduction can be suppressed by the present invention, thereby extending the roll replacement cycle and reducing the manufacturing cost.
In addition, Rpk (4 averages) of the above-mentioned this invention example and a comparative example is an average value of Rpk of 4 rolls. Moreover, Rpk of each roll was measured using the surface test of Surftest 301 (made by Mitutoyo Co., Ltd.) in the longitudinal direction of the roll.

(Example 2)
In the same equipment as in Example 1, experiments were conducted by changing the Rpk of the dimple roll. The condition of Rpk was set so that the average of four lines became 1 μm every 1 to 13 μm. The surface hardness Hs of the roll, the hardness Hv of the sprayed layer, and the thickness of the sprayed layer were performed under the same conditions as in Example 1. It was investigated whether slippage of the steel plate occurred in the bridle roll during use for 6 months and whether uneven gloss occurred on the steel plate surface. In addition, it was set as evaluation of x, if a slip and gloss unevenness occur at least once during use for 6 months. The applied plate thickness of the steel plate was 0.18 mm, the plate width was 850 mm, and the unit tension was 5 kgf / mm ² . Also, the line speed was 600 mpm. In addition, the yield strength of the plate thickness in the present Example 2 was 28-35 kgf / mm < ² >. In this evaluation period, an acceleration unit accelerating from 50 to 600 mpm in 3 minutes and a decelerating unit decelerating from 600 to 50 mpm in 3 minutes were generated 14400 times each. The results are shown in FIG. In the figure, "o" indicates that slip (or uneven gloss) did not occur, and "x" indicates that slip (or uneven gloss) occurred. It was shown in FIG. 5 that when Rpk is in the range of 2 μm to 12 μm, it is possible to prevent the slip of the steel plate and to stably prevent the occurrence of uneven gloss on the surface of the steel plate.
In Example 2, the occurrence of slip and uneven gloss was examined by passing the manufactured thin steel plate coil through an inspection line and inspecting the entire lengths of the front and back surfaces of the thin steel sheet. The occurrence of the slip is determined from the occurrence of a large number of local defects in the longitudinal direction due to the slip on the front and back surfaces (front and back) of the thin steel sheet coil. It was determined that a slip occurred if a longitudinal local scab was observed at any one place on the front and back. If no longitudinal wrinkles were observed anywhere on the front and back, it was determined that no slip occurred. On the other hand, the gloss unevenness is observed as a minute scratch mark which looks like glittering when it is incident on the coil surface by incandescent light. When a scratch mark was observed also in any one place on front and back, it was determined that uneven gloss occurred. When no scratch marks were observed anywhere on the front and back sides, it was judged that uneven gloss did not occur.

表１より、Ｒｐｋ０が本発明範囲内となるロール（ロールＮｏ．１〜７）では、６ヵ月を超えて１２ヵ月使用してもスリップおよび光沢ムラが発生していないことがわかる。特に、シェル部材質がＳ４５ＣのうちロールＮｏ．３〜６では、溶射層硬さ（Ｈｖ）が高くなるとともに、スリップおよび光沢ムラが発生しない期間が長くなっていることが判る。
一方、比較例として、シェル部の材質がＳ４５Ｃ、シェル部の表面硬度（Ｈｓ）が６８、溶射材料がＷＣ−２０％ＣｒＣ／５％Ｎｉ＋２２％Ｎｉのディンプルロールを準備し、同様の条件で調査した。なお、このディンプルロールは、Ｒｐｋ０が１．３（μｍ）（４本平均）であり、溶射層硬さ（Ｈｖ）（４本平均）が１１００であった。この場合には、評価開始時よりスリップが発生したため、試験を中止した。(Example 3)
In Example 3, a plurality of dimple rolls were prepared, and the following experiment was performed. For some rolls, S45C was used as the material of the shell portion shown in FIG. 6 and the surface hardness (Hs) (average of 4 pieces) of the shell portion was in the range of 68 to 77 by induction hardening. In the remaining rolls, SUJ2 was used as the material of the shell portion, and the surface hardness (Hs) (average of 4 rolls) of the shell portion was set to 84 by induction hardening. The surface hardness (Hs) of the shell portion was measured at five points in the longitudinal direction of each roll for each roll, and the average value was taken as the measured value. Next, the thermal spray materials shown in Table 1 were sprayed onto the shell portions of the respective rolls to obtain thermal spray layer hardness (thermal spray film hardness) (Hv). It adjusted so that Rpk of each roll surface might become a value (four-piece average) shown to Rpk0 of Table 1 by shot blast + surface adjustment. The unit of Rpk is μm. The Rpk value was determined in the same manner as in Example 1. Next, in the same equipment as in Example 1, whether or not the steel plate slipped at the bridle roll during use at 6, 12, 12, 18, 30, and 36 months It investigated whether each nonuniformity happened or not. The steel plate thickness, plate width, unit tension, line speed, and yield strength of plate thickness are the same as in Example 2. The thickness (average of 4) of the sprayed layer was 0.05 mm.
The occurrence of slip and uneven gloss was evaluated in light of the following criteria. In addition, the symbol "-" in the evaluation result column of Table 1 means that the test was stopped because a slip occurred.
<Evaluation criteria for occurrence of slip>
The manufactured thin steel plate coil was passed through an inspection line, and examined by inspecting the total length of the front and back surfaces of the thin steel plate. As in the second embodiment, the presence or absence of the slip is determined depending on whether or not the front and back surfaces are wrinkled locally in the longitudinal direction of the thin steel plate coil. The evaluation results of the occurrence of slip show the maximum period (month) in which the slip did not occur.
<Evaluation criteria for occurrence of uneven gloss>
The manufactured thin steel plate coil was passed through an inspection line, and examined by inspecting the total length of the front and back surfaces of the thin steel plate. The occurrence of uneven gloss when using a roll for more than 6 months is determined depending on whether or not a local, longitudinal crease due to slip is observed. When the smear is observed once or more during the use period, it is evaluated as uneven gloss "occurrence". The evaluation results of the occurrence of uneven gloss were given symbols (o, x) according to the following criteria.
○: no uneven gloss ×: uneven gloss The obtained results are shown in Table 1. In Table 1, the Rpk value (unit: μm) (average of 4 lines) after the experiment is shown in the upper part of the evaluation period column of the evaluation result, and the evaluation result of the gloss unevenness occurrence is shown in the lower part of the parentheses. The evaluation results of the slip occurrence status are shown in the column of the slip occurrence status of the evaluation result.

It can be seen from Table 1 that in the rolls (roll Nos. 1 to 7) in which Rpk0 falls within the scope of the present invention, no slip and uneven gloss occur even when used for 12 months over 6 months. In particular, the shell member material is roll No. It can be seen that in Nos. 3 to 6, the thermal sprayed layer hardness (Hv) is high, and the period in which the slip and the gloss unevenness are not generated is long.
On the other hand, as a comparative example, a dimple roll having a shell material of S45C, a shell surface hardness (Hs) of 68, and a thermal spray material of WC-20% CrC / 5% Ni + 22% Ni is prepared and investigated under the same conditions. did. In this dimple roll, Rpk0 was 1.3 (μm) (four-line average), and thermal sprayed layer hardness (Hv) (four-line average) was 1100. In this case, since the slip occurred from the start of the evaluation, the test was stopped.

(Example 4)
A dimple roll (roll surface hardness Hs 81 (average of 4 pieces)) was applied to the bridle roll on the temper mill inlet side of the continuous annealing equipment. The surface hardness Hs of each roll was measured at five points in the length direction of the roll cylinder, and the average value was taken as the measured value of each roll. The roll body (shell) was sample 4 in Table 2 and the sprayed layer was sample 1 in Table 3. In addition, in the surface hardness Hs of the roll shown in Table 2, the average value which measured five points in the roll trunk length direction is shown. The applied plate thickness of the steel plate in the continuous annealing equipment was 0.15 mm to 0.6 mm. Moreover, the yield strength of board thickness was 20-37 kgf / mm < ² >. The roll diameter of the dimple roll was 350 mm, and the unit tension was 3.0 to 4.0 kgf / mm ² . The line speed was 40-1150 mpm. Within six months, an acceleration unit accelerating from 40 mpm to 1150 mpm in 5 minutes and a decelerating unit decelerating from 1150 mpm to 40 mpm in 5 minutes were generated 15,000 times each. The Rpk (average of four) of the dimple roll used at the beginning of use was 8 μm, and the Rpk (average of four) of the dimple roll after six months after use was measured, which was 7.4 μm. The hardness Hv (average of four) of the sprayed layer was 1200, and the thickness (average of four) of the sprayed layer was 0.05 mm.

On the other hand, the same experiment as described above was performed using a roll in which a chromium plating film was dimpled as the same bridle roll. In addition, the hardness (Hv) of the chromium plating film was 1000. The thickness (average of 4) of the chromium plating film was 0.05 mm. In addition, as a result of the time-dependent change of Rpk, after passing an arbitrary number selected from the range of the board thickness of 0.15 mm to 0.6 mm respectively, four dimple rolls used as bridle rolls (in the comparative example, The Rpk average for all four normal rolls). The Rpk value was determined in the same manner as in Example 1.
The initial Rpk (average of 4) was 8 μm, but the Rpk (average of 4) at 6 months after use decreased to 1.6 μm. Thus, it has been shown that the roll pk reduction can be suppressed by the present invention, thereby extending the roll replacement cycle and reducing the manufacturing cost. It was also found that the effect of the present invention can be obtained even when the diameter of the dimple roll is 350 mm.

(Example 5)
A dimple roll (roll surface hardness Hs 84 (average of 4 pieces)) was applied to the bridle roll on the temper mill inlet side of the continuous annealing equipment. The surface hardness Hs of each roll was measured at five points in the length direction of the roll cylinder, and the average value was taken as the measured value of each roll. The roll body was Sample 1 in Table 2 and the sprayed layer was Sample 4 in Table 3. In addition, in the surface hardness Hs of the roll shown in Table 2, the average value which measured five points in the roll trunk length direction is shown. The applied plate thickness of the steel plate in continuous annealing equipment was 0.35 mm to 2.7 mm. Moreover, the yield strength of board thickness was 32-65 kgf / mm < ² >. The roll diameter of the dimple roll was 1200 mm, and the unit tension was 4.5 to 5.0 kgf / mm ² . The line speed was 50-515 mpm. Between six months, an acceleration unit accelerating from 50 mpm to 515 mpm in 3 minutes and a decelerating unit decelerating from 515 mpm to 50 mpm in 3 minutes were generated 15,000 times each. The Rpk (average of four lines) of the dimple roll used at the beginning of use was 8 μm, and the Rpk (average of four lines) of the dimple roll six months after use was examined, which was 7.3 μm. The hardness Hv (average of four) of the sprayed layer was 1200, and the thickness (average of four) of the sprayed layer was 0.05 mm.

On the other hand, the same experiment as described above was performed using a roll in which a chromium plating film was dimpled as the same bridle roll. In addition, the hardness (Hv) of the chromium plating film was 1000. The thickness (average of 4) of the chromium plating film was 0.05 mm. In addition, as a result of the time-dependent change of Rpk, after passing an arbitrary number selected from the range of 0.35 mm to 2.7 mm of plate thickness respectively, four dimple rolls used as bridle rolls (in the comparative example, The Rpk average for all four normal rolls). The Rpk value was determined in the same manner as in Example 1.
The initial Rpk (average of 4) was 8 μm, but the Rpk (average of 4) at 6 months after use decreased to 1.4 μm. Thus, it has been shown that the roll pk reduction can be suppressed by the present invention, thereby extending the roll replacement cycle and reducing the manufacturing cost. It was also found that the effect of the present invention can be obtained even when the diameter of the dimple roll is 1200 mm.

(Example 6)
A dimple roll (roll surface hardness Hs 73 (average of 4 pieces)) was applied to the bridle roll on the temper mill inlet side of the continuous annealing equipment. The surface hardness Hs of each roll was measured at five points in the length direction of the roll cylinder, and the average value was taken as the measured value of each roll. The roll barrel was Sample 3 in Table 2 and the sprayed layer was Sample 2 in Table 3. In addition, in the surface hardness Hs of the roll shown in Table 2, the average value which measured five points in the roll trunk length direction is shown. The applied plate thickness of the steel plate in the continuous annealing equipment was 0.35 mm to 1.6 mm. Moreover, the yield strength of board thickness was 35-180 kgf / mm < ² >. The roll diameter of the dimple roll was 1000 mm, and the unit tension was 3.0 to 4.0 kgf / mm ² . The line speed was 50-560 mpm. Between 6 months, an acceleration part accelerating from 50 mpm to 560 mpm in 4 minutes and a decelerating part decelerating from 560 mpm to 50 mpm in 4 minutes were generated 14400 times each. The Rpk (average of four) of the dimple roll used at the beginning of use was 8 μm, and the Rpk (average of four) of the dimple roll after six months after use was measured, which was 7.4 μm. The hardness Hv (average of four) of the sprayed layer was 1200, and the thickness (average of four) of the sprayed layer was 0.05 mm.

On the other hand, the same experiment as described above was performed using a roll in which a chromium plating film was dimpled as the same bridle roll. In addition, the hardness (Hv) of the chromium plating film was 1000. The thickness (average of 4) of the chromium plating film was 0.05 mm. In addition, as a result of the time-dependent change of Rpk, after passing an arbitrary number selected from the range of 0.35 mm to 1.6 mm of plate thickness respectively, four dimple rolls used as a bridle roll (in the comparative example, The Rpk average for all four normal rolls). The Rpk value was determined in the same manner as in Example 1.
The initial Rpk (average of 4) was 8 μm, but the Rpk (average of 4) at 6 months after use decreased to 1.5 μm. Thus, it has been shown that the roll pk reduction can be suppressed by the present invention, thereby extending the roll replacement cycle and reducing the manufacturing cost. It was also found that the effect of the present invention can be obtained even when the diameter of the dimple roll is 1000 mm.

Claims (11)

  A steel sheet passing method using a steel sheet contact roll in which a dimple sprayed layer is formed on the surface and the surface Rpk is 2 μm to 12 μm.   The steel sheet passing method according to claim 1, wherein the hardness (Hv) of the sprayed layer is 1200 to 2000.   The steel sheet passing method according to claim 1 or 2, wherein the hardness (Hs) of the material of the base of the sprayed layer is 70 to 85.   The sheet passing method of a steel plate according to any one of claims 1 to 3, wherein a roll outer diameter of the steel plate contact roll is 250 mm to 1600 mm. 5. The steel plate contact roll according to any one of claims 1 to 4, wherein a steel plate having a thickness of 0.13 mm to 2.7 mm is passed by the steel plate contact roll under a condition that a unit tension of 1 to ²⁰ kgf / mm ² is applied. The sheet passing method of the described steel plate.   The manufacturing method of the steel plate which manufactures a steel plate using the passing-through method of the steel plate of any one of Claims 1-5.   The manufacturing equipment of the thin steel plate provided with the steel plate contact roll in which the dimple thermal-sprayed layer is formed in the surface, and Rpk of the surface is 2 micrometers-12 micrometers.   The manufacturing equipment of the steel plate of Claim 7 whose hardness (Hv) of the said sprayed layer is 1200-2000.   The manufacturing equipment of the steel plate of Claim 7 or 8 whose hardness (Hs) of the material of the base of the said sprayed layer is 70-85.   The manufacturing equipment of the thin plate of any one of Claims 7-9 whose roll outer diameter of the said steel plate contact roll is 250 mm-1600 mm. 11. The steel plate contact roll according to any one of claims 7 to 10, wherein a steel plate having a thickness of 0.13 mm to 2.7 mm can be passed by the steel plate contact roll under a condition that a unit tension of 1 to ²⁰ kgf / mm ² is applied. The manufacturing equipment of the thin steel plate of item 1.

Images