Facility for processing metal strip, and method for processing metal strip

Abstract

To provide an apparatus and a method for removing a lubricant remaining on the surface of a metal strip, which can be applied regardless of the type of an apparatus used for supplying a lubricant to the metal strip for processing, and which can remove a water-soluble lubricant containing moisture remaining on the surface of the metal strip to suppress oil stains and the occurrence of surface defects.SOLUTION: A processing facility 2, 17 for a metal strip 1 comprises: a processing apparatus 5, 20 configured to supply a water-soluble lubricant containing moisture to the metal strip 1 and process the metal strip 1; and a removal apparatus 7 configured to remove, by means of a fluid, the water-soluble lubricant containing moisture remaining on the surface of the metal strip 1 after being processed by the processing apparatus 5, 20. The removal apparatus 7 includes nozzle heads 13 that inject a fluid toward the metal strip 1. The nozzle heads 13 are arranged on respective front and rear surfaces of the metal strip 1 in the vertical direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a metal strip processing facility and a metal strip processing method. [Background technology]

[0002] Among steel strips, the surface quality of stainless steel strips used in their pure form is important, and in particular, the gloss and beauty of the surface are directly linked to the appearance when in use.

[0003] Stainless steel strips are usually rolled to a design thickness by cold rolling. Thereafter, the stainless steel strip is annealed, and if necessary, pickled, and may further be subjected to temper rolling. However, since the surface properties of the stainless steel strip after cold rolling affect the surface quality of the stainless steel strip in the final product, it is desirable to complete the cold rolling with a more beautiful surface.

[0004] When cold rolling is performed, a lubricant is usually supplied to the stainless steel strip. Water-soluble lubricants, which have better cooling performance than neat oil, are sometimes used. Water-soluble lubricants include solution-type, soluble-type, and emulsion-type lubricants. All types of water-soluble lubricants are characterized by being dissolved or emulsified in water and used together with water.

[0005] The use of such a water-soluble lubricant containing water during cold rolling is advantageous from the viewpoints of preventing seizure, cooling the steel strip and rolls, and preventing fires. However, if the water-soluble lubricant containing water remains on the steel strip surface, it may cause a defect known as "oil burn."

[0006] Therefore, technologies for preventing such defects have been studied. Patent Document 1 discloses a method in which a wiper device is attached to a cold rolling mill that cold rolls a steel strip, and the wiper device removes water-soluble rolling oil containing moisture that has adhered to the surface of the steel strip. The wiper device is provided with a contact pad made of foamed rubber that comes into contact with the surface of the steel strip.

[0007] Patent Document 2 discloses a method for removing rolling oil and wear particles adhering to the surface of a metal strip in a reversing rolling mill. Specifically, in at least one pass including the final pass during rolling, a wiping pad is pressed against the surface of the metal strip on the entry side of the rolling stand. The wiping pad then removes wear particles and the like adhering to the entry side of the metal strip surface. Also, a wiping roll is pressed against the surface of the metal strip on the exit side of the rolling stand. The wiping roll then removes rolling oil adhering to the surface of the metal strip on the exit side of the rolling stand. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2019-025532 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-137936 Summary of the Invention [Problem to be solved by the invention]

[0009] However, in the method described in Patent Document 1, scum may adhere to the contact pad that is in contact with the steel strip surface, and the scum may fall from the contact pad onto the steel strip surface. Furthermore, if the steel strip is wound with scum adhering to its surface, the scum may cause defects on the steel strip surface, and there is still room for improvement in this regard.

[0010] The method described in Patent Document 2 is applicable only to reversing rolling mills, and cannot be applied to tandem rolling mills that transport steel strips in one direction for rolling, or other equipment, and in this respect there is still room for improvement.

[0011] The present invention has been made to solve the above-mentioned problems, and aims to provide a metal strip processing equipment and a metal strip processing method that can remove lubricant remaining on the surface of a metal strip, thereby suppressing oil burn and preventing the occurrence of surface defects, regardless of the type of device that supplies lubricant to the metal strip and processes it. [Means for solving the problem]

[0012] The means for solving the above problems are as follows. [1] A metal strip processing facility having a processing device that supplies a water-soluble lubricant containing moisture to a metal strip to process the metal strip, and a removal device that uses a fluid to remove the water-soluble lubricant containing moisture remaining on the surface of the metal strip processed by the processing device, the removal device having a nozzle head that sprays the fluid toward the metal strip, and the nozzle heads are arranged on the front and back sides of the metal strip in the vertical direction. [2] The nozzle head has a slit nozzle that sprays the fluid onto the surface of the metal strip, the slit nozzle is arranged to extend in the width direction of the metal strip, and the length of the slit nozzle in the width direction is longer than the width of the metal strip. [1] Metal strip processing equipment. [3] The nozzle head has a plurality of nozzles for spraying the fluid onto the surface of the metal strip, the plurality of nozzles being arranged in a row in the width direction of the metal strip, and the distance between the nozzles located on both sides in the width direction among the plurality of nozzles arranged in the width direction is longer than the width of the metal strip. [4] The metal strip processing equipment according to any one of [1] to [3], wherein the fluid is any one of air, neat oil, an alkaline aqueous solution, and an organic solvent. [5] The metal strip processing equipment according to any one of [1] to [4], wherein the metal strip is a stainless steel strip. [6] The metal strip processing equipment according to any one of [1] to [5], wherein the processing device is either a rolling mill or a grinding machine. [7] A method for processing a metal strip, comprising a processing step of supplying a water-soluble lubricant containing water to a metal strip and processing the metal strip, and a removal step of spraying a fluid onto the surface of the metal strip processed in the processing step to remove the water-soluble lubricant containing water remaining on the surface of the metal strip, wherein the removal step involves vertically sandwiching the metal strip and spraying the fluid onto both sides of the metal strip. [Effects of the Invention]

[0013] According to the present invention, regardless of the type of device that supplies lubricant to a metal strip and processes it, it is possible to remove lubricant remaining on the surface of the metal strip, thereby suppressing oil burn and preventing the occurrence of surface defects. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing an example of a metal strip processing device according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a removal device according to a first embodiment. [Figure 3] FIG. 3 is a view taken along the arrow A in FIG. 2. [Figure 4] FIG. 10 is a perspective view of a removal device according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a view taken along arrow B in FIG. 4. [Figure 6] FIG. 10 is a diagram showing an example of a metal strip processing facility according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a diagram showing an example of a metal strip processing facility according to a fourth embodiment of the present invention. [Figure 8] FIG. 10 is a diagram showing an example of a metal strip processing facility according to a fifth embodiment of the present invention. [Figure 9] FIG. 10 is a diagram showing another example of a removal device. DETAILED DESCRIPTION OF THE INVENTION

[0015] (First embodiment) Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of processing equipment 2 for a metal strip 1 according to a first embodiment of the present invention. The processing equipment 2 shown in FIG. 1 is a reverse rolling mill that cold-rolls a steel strip 1, which is a metal strip. The steel strip 1 can be, for example, a stainless steel strip. There are no limitations on the stainless steel strip as long as it is produced by a standard method, i.e., a conventionally known method. The stainless steel strip may be produced, for example, by hot-rolling a slab produced by adjusting the composition, and then annealing, descaling, or pickling by a standard method.

[0016] The reversing rolling equipment 2 shown in FIG. 1 has two reels 3 and 4, a reversing rolling mill 5, a coolant nozzle 6, and a removal device 7.

[0017] (reel) Each of the reels 3, 4 delivers the coiled steel strip 1 toward the reversing rolling mill 5, and also reels up the steel strip 1 that has been rolled in the reversing rolling mill 5. In the example shown in FIG. 1, each of the reels 3, 4 is provided on both sides of the reversing rolling mill 2 in the conveying direction of the steel strip 1 in the reversing rolling mill 2 (left-right direction in FIG. 1). For example, the steel strip 1 delivered from the reel 4 arranged on one side (right side in FIG. 1) of the reversing rolling mill 2 in the conveying direction of the steel strip 1 is conveyed toward the other side (left side in FIG. 1) of the reversing rolling mill 2 in the conveying direction. The steel strip 1 is then rolled in the reversing rolling mill 5. Thereafter, the steel strip 1 is further conveyed toward the other side (left side in FIG. 1) and wound up on the reel 3 on the other side (left side in FIG. 1). Thereafter, the steel strip 1 taken up by the reel 3 on the other side (left side in Figure 1) is unwound from the reel 3 on the other side (left side in Figure 1) and transported toward one side (right side in Figure 1) where it is rolled in a reversing rolling mill 5. Thereafter, the steel strip 1 is rewound onto the reel 4 on one side (right side in Figure 1). In this way, the two reels 3, 4 of the reversing rolling equipment 2 alternately repeat the unwound and rewound operations of the steel strip 1.

[0018] (reverse rolling mill) The reversing rolling mill 5 may be a conventionally known type. The reversing rolling mill 5 shown in FIG. 1 has a pair of work rolls 8, multiple intermediate rolls 9 supporting the work rolls 8, and backup rolls 10 supporting the intermediate rolls 9. The pair of work rolls 8 are arranged vertically side by side, and a steel strip 1 is sandwiched between the pair of work rolls 8. The steel strip 1 is then reciprocated between the work rolls 8 multiple times (reciprocated left and right in FIG. 1 ) to roll the steel strip 1 to a predetermined thickness. Note that passing the steel strip 1 between the pair of work rolls 8 in the longitudinal direction and rolling it from its leading end to its tail end is called one pass. The number of times the steel strip 1 is passed between the pair of work rolls 8 and rolled is called the number of passes. The final rolling performed on the steel strip 1 in the reversing rolling mill 5 is called the final pass.

[0019] (coolant nozzle) The coolant nozzles 6 spray coolant onto the work rolls 8 and the steel strip 1 when the steel strip 1 is rolled by the reversing rolling mill 5, thereby lubricating and cooling the work rolls 8 and the steel strip 1. In the example shown in Figure 1, coolant nozzles are provided on both sides of the reversing rolling mill 5, above and below the steel strip 1, in the conveying direction of the steel strip 1 in the reversing rolling mill 5. The coolant nozzles 6 are connected to a coolant supply source (not shown), a pump (not shown), and a coolant cooling device (not shown).

[0020] The coolant may be, for example, a water-soluble lubricant. The water-soluble lubricant is a lubricant that is mixed with water before use, and examples of the water-soluble lubricant include a lubricant that is dissolved in water before use, or a lubricant that is emulsified before use. In the example shown in FIG. 1, when rolling a steel strip 1 using a reversing rolling mill 5, a water-soluble lubricant containing water is sprayed onto the steel strip 1 as a coolant. The water-soluble lubricant may be any of a solution type, a soluble type, or an emulsion type.

[0021] (removal device) The remover 7 removes coolant and foreign matter remaining on the surface of the steel strip 1 after the final pass. This is to avoid the possibility that coolant remaining on the surface of the steel strip 1 may cause a defect known as oil burn. It also aims to prevent foreign matter from being caught in the steel strip 1 when the steel strip 1 is reeled up, thereby preventing scratches on the steel strip 1. In the example shown in FIG. 1, the remover 7 is disposed between the reverse rolling mill 5 and the reel 4 that reeled up the steel strip 1 after the final pass, in the conveying direction of the steel strip 1. The remover 7 also has nozzle heads 13, and in the example shown in FIG. 1, each nozzle head 13 is disposed on both sides of the steel strip 1, sandwiching the steel strip 1 in the vertical direction. As shown in FIG. 1, the nozzle heads 13 are disposed side by side in the vertical direction. Here, "side by side" means that the nozzle heads 13 overlap each other in the vertical direction. The vertical distance between each remover 7 and the steel strip 1 is preset. The conveying direction of the steel strip 1 that has made the final pass is indicated by an arrow in FIG.

[0022] A fluid supply source 12 is connected to each nozzle head 13 via a pump 11. By adjusting the discharge pressure of the pump 11, the fluid is sprayed onto the surface of the steel strip 1 from a nozzle 12 (described later) provided on the nozzle head 13 at a predetermined spray pressure (MPa) or higher. The above-mentioned predetermined spray pressure is preferably 0.1 MPa, for example. If the spray pressure is less than 0.1 MPa, the pressure when the fluid collides with the surface of the steel strip 1 will be excessively small, and it may be impossible to remove the water-soluble lubricant containing moisture remaining on the surface of the steel strip 1.

[0023] The coolant removal efficiency by the removal device 7 varies mainly depending on the fluid injection pressure, the vertical distance between the steel strip 1 and the removal device 7, and the conveying speed of the steel strip 1. The above-mentioned predetermined injection pressure is the minimum value of the injection pressure when the above-mentioned distance and conveying speed are each at their maximum values. Therefore, the above-mentioned predetermined injection pressure can be determined in advance through experiments as the fluid injection pressure that satisfies the desired removal efficiency when the above-mentioned distance and conveying speed are each at their maximum values. Note that the maximum value of the distance between the steel strip 1 and each removal device 7 is roughly determined due to installation space constraints. The maximum value of the conveying speed of the steel strip 1 is roughly determined due to equipment constraints.

[0024] (fluid) The fluid used in the removal device 7 may be either a gas or a liquid. Examples of gases include air and nitrogen gas, but air is preferred due to its material cost. Examples of liquids include a water-free lubricant, an alkaline aqueous solution, or an organic solvent. Examples of lubricants include neat oil. Examples of neat oil include cold-rolling oils primarily composed of mineral oil. Examples of alkaline aqueous solutions include aqueous solutions of alkaline cleaners containing alkali agents, chelating agents, or surfactants. Organic solvents may be commercially available hydrocarbon-based cleaners, such as acetone, toluene, and benzine. However, commercially available industrial hydrocarbon-based cleaners that take environmental impact and human safety into consideration are preferred. In the following description, the method of removing coolant from the surface of the steel strip 1 using a gas in the removal device 7 is referred to as gas wiping. The method of removing coolant from the surface of the steel strip 1 using a liquid in the removal device 7 is referred to as liquid wiping.

[0025] The above-mentioned fluid may be sprayed from a nozzle described later onto the surface of the steel strip 1 while still at room temperature, but it is preferable to spray a fluid heated to a high temperature by a heater (not shown) onto the surface of the steel strip 1 from a nozzle. This is because when the coolant remaining on the surface of the steel strip 1 is exposed to a high-temperature fluid, the heat warms the coolant, reducing its viscosity. This makes it easier for the coolant to flow on the surface of the steel strip 1, and the coolant is more easily removed by the fluid that collides with the surface of the steel strip 1.

[0026] The heater is preferably provided in the middle of the piping that supplies the fluid from the fluid supply source to the nozzle head 13 of the removal device 7. Of the above-mentioned piping, it is more preferable to provide the heater between the pump and the nozzle head 13. This is because the distance that the fluid heated by the heater travels is shortened, thereby preventing the fluid from cooling during travel.

[0027] The temperature of the fluid heated by the heater is preferably 100°C or higher. Furthermore, considering the thermal effect on the surface of the steel strip 1, the temperature of the fluid heated by the heater is preferably less than 600°C. Furthermore, considering the heat resistance of the piping, the temperature of the fluid heated by the heater is preferably 250°C or lower. In other words, the temperature of the fluid heated by the heater is preferably 100 to less than 600°C, and more preferably 100 to 250°C or lower.

[0028] The configuration for spraying a fluid in the removal device 7 will be described. Figure 2 is a perspective view of the removal device 7 of the first embodiment. Figure 3 is a view taken along the arrow A in Figure 2. As shown in Figures 2 and 3, the removal device 7 has a nozzle head 13 extending in the width direction of the steel strip 1, and a pump 11 is connected to the nozzle head 13 so as to be able to supply a fluid to the nozzle head 13. The nozzle head 13 shown in Figures 2 and 3 has a slit nozzle 14.

[0029] The slit nozzles 14 extend in the width direction of the steel strip 1, and the length d1 of the slit nozzles 14 in the width direction is set longer than the width D of the steel strip 1, as shown in Figure 3. This is so that the fluid sprayed from the slit nozzles 14 collides with the surface of the steel strip 1 over the entire width of the steel strip 1. Furthermore, each slit nozzle 14 is set to spray the fluid approximately parallel to its axis along the vertical direction, and the slit nozzle 14U located above the steel strip 1 in the vertical direction and the slit nozzle 14D located below the steel strip 1 in the vertical direction overlap each other in the vertical direction. Therefore, the collision positions of the fluid sprayed from each slit nozzle 14U, 14D on both sides of the steel strip 1 with respect to the steel strip 1 are approximately the same on both the front and back sides of the steel strip 1.

[0030] (Actions and Effects of the First Embodiment) According to the first embodiment, when rolling of the steel strip 1 in the reversing rolling mill 5 is completed, the coolant and foreign matter remaining on the surface of the steel strip 1 are removed over the entire width of the steel strip 1 by the fluid sprayed from the slit nozzles 14U and 14D of the removal device 7. Furthermore, the collision positions of the fluid sprayed from each slit nozzle 14U and 14D on the steel strip 1 are approximately the same on the front and back sides of the steel strip 1. Therefore, the coolant removed by the fluid that collides with one of the two sides of the steel strip 1 can be prevented from moving around and remaining on the other side. The steel strip 1 is then wound by the reel 4. Therefore, it is possible to prevent foreign matter from being caught in the steel strip 1 when the steel strip 1 is wound. This prevents scratches from occurring on the surface of the wound steel strip 1. Furthermore, even if the steel strip 1 is stored until the next process after winding, the coolant has been removed, so it is possible to prevent oil burns from occurring on the surface of the steel strip 1. As a result, according to the first embodiment, a steel strip 1 with a beautiful surface free from scratches and oil stain defects can be produced.

[0031] Although the positions of the slit nozzles 14U and 14D in the conveying direction of the steel strip 1 are preferably approximately the same, they may be offset in the conveying direction of the steel strip 1. In this case, the lower slit nozzle 14D of the steel strip 1 is preferably positioned downstream of the upper slit nozzle 14U in the conveying direction of the steel strip 1. The reason for this is explained below. The coolant removed from the front surface of the steel strip 1 by the fluid sprayed from the upper slit nozzle 14U may migrate around the edge of the steel strip 1 and adhere to the back surface of the steel strip 1. If the upper slit nozzle 14U is positioned downstream of the lower slit nozzle 14D in the conveying direction of the steel strip 1, the coolant adhered to the back surface of the steel strip 1 cannot be removed by the fluid sprayed from the lower slit nozzle 14D. Therefore, when the positions of the slit nozzles 14U and 14D are offset in the conveying direction, the lower slit nozzle 14D of the steel strip 1 is preferably positioned downstream of the upper slit nozzle 14U in the conveying direction. Furthermore, by doing this, the back surface of the steel strip 1 is in close contact with the surface of the steel strip 1 wound on the reel 4. The front surface of the steel strip 1 is wound one rotation later on the reel 4. Therefore, the coolant adhering to the surface of the steel strip 1 is more likely to evaporate or fall off during the one rotation mentioned above, compared to when it is adhering to the back surface.

[0032] 1 to 3 is configured to spray a fluid onto the surface of the steel strip 1 to remove coolant and foreign matter remaining on the surface of the steel strip 1. Therefore, compared to when coolant is removed using a solid member such as a sponge or a draining board, there is no contact with the solid member. This prevents scratches from occurring on the surface of the steel strip 1 due to contact with the solid member. Furthermore, it prevents scratches from occurring on the surface of the steel strip 1 when the steel strip 1 is wound up while the foreign matter adhering to the solid member falls onto the surface of the steel strip 1.

[0033] (Second embodiment) Fig. 4 is a perspective view of a removal device of a second embodiment. Fig. 5 is a view taken along the arrow B in Fig. 4. The example shown in Figs. 4 and 5 is an example in which a plurality of nozzles 15 are provided in a nozzle head 13 instead of a slit nozzle 14. Since other configurations are the same as those shown in Figs. 2 and 3, in Figs. 4 and 5, the same components as those shown in Figs. 2 and 3 are denoted by the same reference numerals as those in Figs. 2 and 3, and description thereof will be omitted.

[0034] In the example shown in Figures 4 and 5, a plurality of nozzles 15 are arranged in the width direction of the steel strip 1 in the nozzle head 13. Of the plurality of nozzles 15 arranged in the width direction, the distance d2 between the nozzles 15R and 15L located on both sides in the width direction is set to be longer than the width D of the steel strip 1. In addition, the fluids sprayed from adjacent nozzles 15 are configured to overlap slightly in the width direction. In other words, the fluid spray areas of each nozzle 15 are configured to overlap. This allows the fluid sprayed from each nozzle 15 to collide with the surface of the steel strip 1 without any gaps across the entire width of the steel strip 1.

[0035] Furthermore, each nozzle 15 is set to spray fluid approximately parallel to an axis along the vertical direction, and each nozzle 15 located above the steel strip 1 in the vertical direction and each nozzle 15 located below the steel strip 1 in the vertical direction overlap each other in the vertical direction. Therefore, the collision positions of the fluid sprayed from each nozzle 15 on both sides of the steel strip 1 onto the steel strip 1 are approximately the same on the front and back of the steel strip 1.

[0036] (Actions and Effects of the Second Embodiment) Even in the second embodiment, when rolling of the steel strip 1 in the reversing rolling mill 5 is completed, the coolant and foreign matter remaining on the surface of the steel strip 1 are removed over the entire width of the steel strip 1 by the fluid sprayed from each nozzle 15 of the removal device 7. Therefore, even in the second embodiment, the same actions and effects as in the first embodiment can be obtained. Note that the multiple nozzles 15 only need to be configured so that the fluid sprayed from those nozzles 15 collides with the entire width of the steel strip 1, and so long as this configuration is achieved, the nozzles 15 may be arranged, for example, in a staggered pattern (not shown). Even with this configuration, the same actions and effects as in the first embodiment can be obtained.

[0037] (Third embodiment) FIG. 6 is a diagram showing an example of a metal strip processing facility according to a third embodiment of the present invention. The example shown in FIG. 6 shows a removable cleaning tank 16 for storing a cleaning liquid for removing coolant and foreign matter remaining on the surface of the steel strip 1, which is located between the reversing rolling mill 5 and the remover 7 in the conveying direction of the steel strip 1 that has undergone the final pass. The cleaning tank 16 is removed from the reverse rolling facility 2 shown in FIG. 6 until the pass one pass before the final pass is completed. After the pass one pass before the final pass is completed, the cleaning tank 16 is installed between the reversing rolling mill 5 and the remover 7. FIG. 6 shows this state. The steel strip 1 that has undergone the final pass is then continuously immersed in the cleaning liquid stored in the cleaning tank 16 to clean the steel strip 1.

[0038] The cleaning liquid may be a water-free lubricant, an alkaline aqueous solution, or an organic solvent. The cleaning tank 16 may be provided with an agitator or agitation nozzle (not shown) for agitating the cleaning liquid, in order to facilitate the removal of water-soluble lubricants and foreign matter remaining on the surface of the steel strip 1 by the cleaning liquid. The agitator may be a rotating blade that rotates the liquid in the cleaning tank 16. The agitation nozzle may be designed to spray the cleaning liquid in the cleaning tank 16 onto the steel strip 1.

[0039] In the removal device 7 of the third embodiment, the fluid sprayed onto the steel strip 1 may be either a gas or a liquid, as in the first and second embodiments, but it is preferable to use a gas. This is because spraying a gas not only removes the coolant and foreign matter still remaining on the surface of the steel strip 1 after cleaning in the cleaning tank 16, but also dries the surface of the steel strip 1. Furthermore, the nozzle head 13 of the removal device 7 may be provided with a slit nozzle 14 or multiple nozzles 15. Since the other configuration is the same as the configuration shown in Figure 1, in Figure 6, the same components as those shown in Figure 1 are designated by the same reference numerals as in Figure 1, and their description will be omitted.

[0040] (Actions and Effects of the Third Embodiment) In the third embodiment, by immersing the steel strip 1 in the cleaning liquid in the cleaning tank 16, the coolant remaining on the surface of the steel strip 1 can be replaced and removed by the cleaning liquid in the cleaning tank 16. In addition, after cleaning in the cleaning tank 16, gas is sprayed onto the surface of the steel strip 1 in the removal device 7. This makes it possible to remove the coolant and foreign matter still remaining on the surface of the steel strip 1 and to dry the surface of the steel strip 1. As a result, according to the third embodiment, the coolant and foreign matter remaining on the surface of the steel strip 1 can be removed more effectively than according to the first and second embodiments.

[0041] (Fourth embodiment) Fig. 7 is a diagram showing an example of a metal strip processing facility according to a fourth embodiment of the present invention. The processing facility shown in Fig. 7 is a tandem rolling facility 17 having two reels 18, 19, with the steel strip 1 being paid out from one reel 18 and taken up by the other reel 19. As shown in Fig. 7, a tandem rolling mill 20 is provided between the two reels 18, 19 in the conveying direction of the steel strip 1, and a removal device 7 is provided between the tandem rolling mill 20 and the reel 19 that takes up the steel strip 1 in the conveying direction.

[0042] The tandem rolling mill 20 has a plurality of rolling stands 21, 22, 23, and is an apparatus for making the thickness of the steel strip 1 a target thickness by passing the steel strip 1 in one direction through the rolling stands 21, 22, 23. In the example shown in Figure 7, the tandem rolling mill has three rolling stands 21, 22, 23, but the number of rolling stands 21, 22, 23 is not limited.

[0043] In the removal device 7 of the fourth embodiment, the fluid sprayed onto the steel strip 1 may be either a gas or a liquid. Furthermore, the nozzle head 13 of the removal device 7 may be provided with a slit nozzle 14 or with multiple nozzles 15. In the example shown in Figure 7, the removal device 7 sprays a fluid slightly upstream in the conveying direction of the steel strip 1, and the fluid removes the coolant remaining on the surface of the steel strip 1. Since the other configuration is the same as the configuration shown in Figure 1, in Figure 7, the same components as those shown in Figure 1 are assigned the same reference numerals as in Figure 1, and their description will be omitted.

[0044] (Actions and Effects of the Fourth Embodiment) Even in the fourth embodiment, when rolling of the steel strip 1 in the tandem rolling mill 20 is completed, the coolant and foreign matter remaining on the surface of the steel strip 1 are removed over the entire width of the steel strip 1 by the fluid sprayed from the removal device 7. Therefore, even in the fourth embodiment, it is possible to obtain actions and effects that are substantially the same as those of the first and second embodiments.

[0045] (Fifth embodiment) Fig. 8 is a diagram showing an example of a metal strip processing facility according to a fifth embodiment of the present invention. The example shown in Fig. 8 is an example in which the above-mentioned cleaning tank 16 is provided between a tandem rolling mill 20 and a removal device 7. Since other configurations are the same as those shown in Fig. 7, in Fig. 8, the same components as those shown in Fig. 7 are assigned the same reference numerals as in Fig. 7, and description thereof will be omitted.

[0046] (Actions and Effects of the Fifth Embodiment) In the fifth embodiment, the steel strip 1 after rolling is immersed in the cleaning liquid in the cleaning tank 16, whereby the coolant remaining on the surface of the steel strip 1 is replaced with the cleaning liquid in the cleaning tank 16. After that, the coolant and foreign matter still remaining on the surface of the steel strip 1 are removed in the removal device 7. Therefore, in the fifth embodiment, the coolant and foreign matter remaining on the surface of the steel strip 1 can be removed more effectively than in the fourth embodiment.

[0047] The present invention is not limited to the above-described embodiments. For example, in the above-described embodiments, the processing apparatus has been described using a reversing rolling mill 5 and a tandem rolling mill 20 as examples, but the processing apparatus may be a grinding machine (not shown) instead of the rolling mills 5 and 20. In other words, the processing apparatus is not limited to the rolling mills 5 and 20, and may be any apparatus that processes a steel strip using the above-described coolant.

[0048] Furthermore, in the removal device 7 of the first to third embodiments, instead of spraying the fluid substantially parallel to the vertical axis, the fluid may be sprayed upstream in the conveying direction of the steel strip 1. With this configuration, the direction of the fluid sprayed from the removal device 7 is opposed to the conveying direction of the steel strip 1 that has made the final pass. Therefore, coolant and foreign matter remaining on the surface of the steel strip 1 can be removed more effectively than when the fluid is sprayed substantially parallel to the vertical axis. Furthermore, the spray pressure of the fluid from the removal device 7 located lower in the vertical direction may be higher than the spray pressure of the fluid from the removal device 7 located higher in the vertical direction. With this configuration, the fluid sprayed from the removal device 7 located lower can blow away coolant that moves to the lower surface of the steel strip 1 due to gravity, preventing it from adhering to the lower surface of the steel strip 1.

[0049] Furthermore, when multiple nozzles 15 are arranged in the width direction of the steel strip 1 in the removal device 7, each nozzle 15 located at both ends of the removal device 7 in the width direction may be configured to spray fluid toward the outside, opposite the steel strip 1 in the width direction. Figure 9 shows an example of this. The spray direction of the fluid sprayed from each nozzle 15 is indicated by an arrow in Figure 9. By configuring as shown in Figure 9, the coolant and foreign matter removed by the fluid can be pushed outward from the steel strip 1, preventing them from remaining on the surface of the steel strip 1. Even with this configuration, it is possible to obtain functions and effects substantially similar to those of the above-mentioned embodiments. Note that the method of processing the steel strip 1 using the rolling equipment 2, 17 and equipment equipped with a grinding machine corresponds to the processing method of this embodiment. The process of processing the steel strip 1 using the rolling equipment 5, 20 and grinding machine corresponds to the processing process of this embodiment. Furthermore, the process of removing the coolant from the surface of the steel strip 1 using the removal device 7 corresponds to the removal process of this embodiment.

[0050] Furthermore, when multiple nozzles 15 are arranged in the width direction of the steel strip 1 in the removal device 7, the nozzle 15 located on the central side of the removal device 7 in the width direction may be arranged closer to the rolling mills 2, 20 in the conveying direction than the nozzles 15 located on both end sides of the removal device 7 in the width direction. In other words, the multiple nozzles 15 may be arranged in a V-shape. In this way, the coolant and foreign matter can be efficiently pushed out and removed by the fluid sprayed from each nozzle 15 from the central side in the width direction toward the outside in the width direction.

[0051] Furthermore, when multiple nozzles 15 are provided, it is preferable that the distance between the nozzle 15 located at the center in the width direction and the nozzle 15 located at the outermost position in the width direction is less than 1000 mm. This is to avoid an increase in the size of the equipment. Also, it is possible to prevent the coolant removed by the fluid sprayed from each nozzle 15 from moving from one side of the steel strip 1 to the other side and adhering to the other side.

[0052] When spraying fluid from the nozzles 15 toward the upstream side in the conveying direction of the steel strip 1, it is preferable that the angle formed between the steel strip 1 and the central axis of each nozzle is 45° or more and less than 90°. This is because if the angle is less than 45°, it becomes difficult to remove the coolant with the fluid sprayed from each nozzle 15, and there is also a possibility that the removed coolant will be blown away by the fluid and scattered around, and this is to avoid this.

[0053] In the example shown in Figure 9, the angle between the central axis of the nozzles 15R, 15L (nozzles on the edge side of the steel sheet 1) located outermost in the width direction and the axis perpendicular to the steel strip 1 is preferably 20° or less. If the angle exceeds 20°, the spray area of ​​the fluid from each nozzle 15R, 15L may not overlap with the spray area of ​​the fluid from the nozzles 15 adjacent to the nozzles 15R, 15L. This may result in the coolant not being able to be removed by the fluid sprayed from each nozzle 15, 15R, 15L. Therefore, the angle is preferably 20° or less. [Example]

[0054] Cold rolling of No. 1-finish stainless steel strips (hereinafter simply referred to as steel strips) made of SUS430 was performed using a reversing rolling mill configured almost identically to the reversing rolling mill shown in Figure 1. Specifically, 15 coils of the above-mentioned steel strip were prepared, and each steel strip was cold rolled while the coolant was removed under the conditions shown in Table 1. After the coolant was removed using a removal device, the steel strip was wound into a coil and stored at room temperature for at least one day (24 hours). The steel strip was then discharged and annealed, pickled, and temper rolled using conventional methods. The surface condition of the steel strip was then observed to determine whether or not there was oil burn or rust, and whether or not there were surface defects. Based on the results of this evaluation, it was determined whether or not the steel strip surface was clean, i.e., whether or not it could be shipped as a product. If the steel strip surface was clean enough to be shipped as a product, it was determined to be acceptable. The conditions for removing the coolant from each steel strip, the presence or absence of oil burn or rust, the presence or absence of surface defects, and the pass / fail judgment results for each steel strip are summarized in Table 1. Note that room temperature means a temperature of about 20 to 25°C.

[0055] [Table 1]

[0056] Nos. 1 to 3 are examples of the present invention. In Nos. 1 and 3, a heater was attached to the pipe supplying air to the removal device, and the air temperature was raised to 90°C by the heater before being sprayed onto the steel strip. In No. 2, room temperature air was sprayed onto the steel strip. In Nos. 1 to 3, no oil burn, rust, or surface defects were observed on the steel strip surface, and the steel strip surface was beautiful. Therefore, they were judged to be acceptable.

[0057] No. 4 is an example of the present invention in which the nozzle on the top surface of the steel strip was positioned 100 mm closer to the reverse rolling mill than the nozzle on the bottom surface of the steel strip, and room temperature air was sprayed onto the steel strip. Rust was observed in two places on the steel strip surface. This is thought to be because when the bottom surface of the steel strip was wiped, coolant was splashed up by the air that collided with the bottom surface of the steel strip, adhering to the top surface of the steel strip and being wound up as is. However, the steel strip surface was beautiful overall and was deemed acceptable.

[0058] No. 5 is an example of the present invention in which the air injection pressure was lower than in Nos. 1 and 3. In No. 5, oil burns were observed in two places on the steel strip surface. This is thought to be because the air injection pressure was lower than in Nos. 1 and 3, so some coolant remained on the steel strip surface. However, overall the steel strip surface was beautiful and passed the test.

[0059] No. 6 is an example of the present invention in which the air temperature was increased to 180°C, which was higher than that of No. 1 and No. 3, and then sprayed onto the steel strip. The surface of the steel strip was beautiful and passed the test.

[0060] No. 7 is a comparative example in which the coolant was removed from the steel strip surface by immersing the steel strip in neat oil stored in a cleaning tank. The temperature of the neat oil was set to 40°C. No. 8 is an example of the present invention in which the steel strip was immersed in the cleaning tank of No. 7 and then gas wiped with room temperature air. In both No. 7 and No. 8, the coolant was successfully removed from both sides of the steel strip. No oil burn, rust, or surface scratches were observed on the steel strip surface, and the steel strip surface was beautiful. Therefore, it was judged to be acceptable.

[0061] Nos. 9 to 11 are examples of the present invention in which neat oil was sprayed onto the surface of the steel strip to remove the coolant from the steel strip surface. In No. 9, the temperature of the neat oil was set to room temperature, while in Nos. 10 and 11, the temperature of the neat oil was set to 40°C. Even with these methods, it was possible to remove the coolant from both sides of the steel strip. No oil burns, rust, or surface scratches were observed on the steel strip surface, and the steel strip surface was beautiful. Therefore, it was judged to be acceptable.

[0062] No. 12 is a comparative example in which the coolant was removed in the same manner as in Patent Document 2. That is, wear debris was removed by a wiping pad arranged on the inlet side of the reversing rolling mill, and coolant was removed by a wiping pad arranged on the outlet side of the reversing rolling mill. No. 12 did not suffer from oil burn or rust, but scratches that were thought to be caused by wear debris adhering to the wiping pad occurred on the steel strip surface, and it was therefore unacceptable.

[0063] Nos. 13 and 14 are comparative examples in which the steel strips were rolled using a reverse rolling mill without removing the coolant, and were then wound into a coil. Oil burns and rust, which were thought to be caused by the coolant, were observed on the steel strip surface, and the steel strips were rejected.

[0064] No. 15 is a comparative example in which the steel strip was not rolled using a reverse rolling mill, but was instead sprayed with coolant after being unwound from a reel and wound into a coil. Oil burns and rust, likely caused by the coolant, were observed on the surface of the steel strip, and the sample was rejected.

[0065] As described above, in the present invention, the coolant is removed from the surface of the steel strip by non-contact wiping devices arranged on both sides of the steel strip in the vertical direction so as to sandwich the steel strip between the non-contact wiping devices. This allows the production of stainless steel sheets with beautiful surfaces free of oil stains, rust, and surface defects. Furthermore, it becomes possible to supply the stainless steel strip to the next process.

[0066] Note that the "exit thickness" listed in Table 1 indicates the thickness of the plate after cold rolling. "Number of passes" indicates the number of rolling passes set according to the target plate thickness after cold rolling. "Wiping method" indicates the type of method for removing water-soluble lubricant containing moisture from the surface of the steel strip, and "wiping material used" indicates the type of fluid and material used to remove the coolant. "Temperature" indicates the temperature of the fluid sprayed by the removal device, and "pressure" indicates the spray pressure of the fluid in the removal device.

[0067] In Table 1, the "〇" in the "Oil Burn Suppression" column indicates that the 2 This indicates that the occurrence of oil burn and rust has been suppressed within the above range. "X" indicates that oil burn and rust have occurred in 5 or more points within the above range. "△" indicates that oil burn and rust have occurred in 2 or less points within the above range. Oil burn and rust refer to hazy or spot-like surface defects that are not the dull color of the original steel strip, but are reddish brown, reddish copper, reddish brown, or yellowish in color.

[0068] In Table 1, the "○" in the "Surface Defect Suppression" column indicates that the surface of the steel strip is 2 "X" indicates that no surface defects have occurred within the above range. "X" indicates that surface defects have occurred within the above range. Surface defects refer to scratches of 2 mm or more in the rolling direction, i.e., in the direction of conveyance of the steel strip in the rolling mill.

[0069] The "◯" in the "Pass / Fail" column in Table 1 indicates that the evaluation result for oil burn and rust is "△" or "◯" and the evaluation result for surface defects is "◯", and the surface of the steel strip is beautiful. The "×" indicates that at least one of the evaluation results for oil burn and rust and the evaluation result for surface defects is "×", and the surface of the steel strip is not beautiful. [Explanation of symbols]

[0070] 1 Steel strip 2. Reverse rolling equipment 3 reels 4 reels 5 Reverse rolling mill 6 coolant nozzles 7 Removal device 8 Work Rolls 9 Intermediate roll 10 Backup Role 11 Pump 12 Fluid Source 13 Nozzle head 14, 14U, 14D slit nozzle 15, 15R, 15L nozzles 16 Cleaning tank 17 Tandem rolling equipment 18 reels 19 reels 20 Tandem rolling mill 21 Rolling Stand 22 Rolling Stand 23 Rolling Stand d1 Length of slit nozzle d2 The distance between nozzles located on both sides of the width of the steel strip among multiple nozzles lined up in the width direction D Steel strip width

Claims

1. A metal strip processing facility having a processing device that processes a metal strip by supplying a water-soluble lubricant containing moisture to the metal strip, a removal device that uses a fluid to remove the water-soluble lubricant containing moisture remaining on the surface of the metal strip processed by the processing device, the removal device has a nozzle head that sprays the fluid toward the metal strip, The nozzle heads are arranged on the front and back sides of the metal strip in the vertical direction. Metal strip processing equipment.

2. the nozzle head has a slit nozzle that injects the fluid onto the surface of the metal strip, 2. The metal strip processing equipment according to claim 1, wherein the slit nozzle is disposed extending in the width direction of the metal strip, and the length of the slit nozzle in the width direction is longer than the width of the metal strip.

3. 2. The metal strip processing equipment according to claim 1, wherein the nozzle head has a plurality of nozzles that spray the fluid onto the surface of the metal strip, the plurality of nozzles are arranged in a row in the width direction of the metal strip, and the distance between the nozzles located on both sides in the width direction among the plurality of nozzles arranged in the width direction is longer than the width of the metal strip.

4. 4. The metal strip processing facility according to claim 1, wherein the fluid is any one of air, neat oil, an alkaline aqueous solution, and an organic solvent.

5. 4. The metal strip processing facility according to claim 1, wherein the metal strip is a stainless steel strip.

6. 5. The metal strip processing equipment according to claim 4, wherein the metal strip is a stainless steel strip.

7. 4. The metal strip processing facility according to claim 1, wherein the processing device is either a rolling mill or a grinding machine.

8. 5. The metal strip processing facility according to claim 4, wherein the processing device is either a rolling mill or a grinding machine.

9. 6. The metal strip processing facility according to claim 5, wherein the processing device is either a rolling mill or a grinding machine.

10. 7. The metal strip processing facility according to claim 6, wherein the processing device is either a rolling mill or a grinding machine.

11. 1. A method for processing a metal strip, comprising a processing step of supplying a water-soluble lubricant containing moisture to a metal strip and processing the metal strip, a removing step of spraying a fluid onto the surface of the metal strip processed in the processing step to remove the water-soluble lubricant containing moisture remaining on the surface of the metal strip, In the removing step, the fluid is sprayed onto the metal strip from both sides of the metal strip while sandwiching the metal strip vertically.

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