JP2014162978A - Method of producing surface-treated steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a surface-treated steel plate which enables thickening of a film of a metal-oxygen compound formed on a metal substrate while preventing occurrence of appearance defects, e.g. arc spots, in the metal substrate.SOLUTION: A plurality of rolls provided in each of a plurality of electrolytic treatment tanks 30 and 40, including a roll for transferring a steel plate to the electrolytic treatment tank and a roll for pulling up the steel plate from the electrolytic treatment tank, consist of a conduction roll 65 connected electrically to a power source for electrifying a DC current to the steel plate and non-conduction rolls 61, 63, 67, 69 and 71 not connected to the power source. The conduction roll is arranged so that, after formation of a metal-oxygen compound on a surface of the steel plate in contact with the roll by an electrolytic treatment, the metal-oxygen compound does not come in contact with the conduction roll, leading to elimination of the possibility of occurrence of arc spots.

Description

  The present invention relates to a method for producing a surface-treated steel sheet.

  As a method for forming a film mainly composed of a metal oxygen compound such as Zr, Al, or Ti on a metal substrate, a method using chemical conversion treatment is widely used. In the method using chemical conversion treatment, the metal substrate is immersed in the treatment liquid, the surface of the metal substrate is etched, and the pH in the vicinity of the surface of the metal substrate is increased, so that the metal oxygen compound is formed on the surface of the metal substrate. Precipitates and a metal oxygen compound film is formed on the metal substrate.

  However, in the method using such a chemical conversion treatment, the rate at which the metal oxygen compound film is formed depends on the chemical reaction rate in the treatment liquid, so that it is long to form the metal oxygen compound film on the metal substrate. There is a problem that it takes time.

  On the other hand, for example, in Patent Document 1, a method of forming a metal oxygen compound film by cathodic electrolysis, that is, using an electrolysis solution containing a metal oxygen compound, is included in the electrolysis solution near the surface of the metal substrate. A method is disclosed in which hydrogen is generated by electrolyzing the generated water, the pH in the vicinity of the surface of the metal substrate is raised, and a metal oxygen compound is deposited on the metal substrate. By using the cathodic electrolysis treatment disclosed in Patent Document 1, it is possible to form a metal oxygen compound film in a shorter time as compared with a method using chemical conversion treatment.

JP 2010-121218 A

  However, the cathode electrolytic treatment disclosed in Patent Document 1 has a configuration including a plurality of electrolytic treatment tanks, and a roll for feeding the metal base material into the electrolytic treatment tank, and the metal base material in the electrolytic treatment tank. Among the rolls to be pulled up, all the rolls are energized rolls (conductor rolls) that are electrically connected to the power source, and the electrolysis is performed by energizing the metal substrate using such energized rolls. Therefore, the following problems arise.

  That is, in the cathodic electrolysis process disclosed in Patent Document 1, the metal oxygen compound film formed by the electrolysis process is an insulating film. Therefore, the metal base material on which the metal oxygen compound film is formed is electrolyzed. An excessive voltage is applied to the energizing roll in order to energize the metal base material from the energizing roll used for lifting from the treatment tank. In this case, a peeled-off product of the metal oxygen compound film formed on the metal base material or a deposit of the electrolytic treatment liquid may be deposited on the current-carrying roll. Since an excessive voltage is applied, unevenness due to such deposits causes high-voltage discharge locally on the energizing roll, which causes discharge traces (arc spots) etc. on the metal substrate. There is a problem that a poor appearance occurs. In addition, in the cathodic electrolysis treatment disclosed in Patent Document 1, a problem that the energizing roll is damaged due to an excessive voltage applied to the energizing roll and local high voltage discharge occurs. In such a case, there is a problem that it is necessary to maintain the energizing roll each time. In addition, when a steel plate with an arc spot is used for a metal can, the arc spot portion becomes a defective part of the surface treatment, which causes a corrosion resistance defect on the inner surface side of the can and an appearance defect on the outer surface side of the can. . In addition, when the arc spot is severe, a hole is formed in the can, leading to leakage of contents.

  In particular, the greater the thickness of the metal oxygen compound film formed on the metal substrate, the higher the insulation, and therefore the voltage applied to such a current-carrying roll tends to increase. Such a problem tends to become more prominent as the thickness of the film is increased. For this reason, it has been difficult to increase the thickness of the metal oxygen compound film without causing the above-described problems.

  The present invention has been made in view of such a situation, and its purpose is to increase the thickness of the metal oxygen compound film formed on the metal substrate while preventing the appearance of defects such as arc spots on the metal substrate. An object of the present invention is to provide a method for producing a surface-treated steel sheet that can be made and can improve the productivity of the surface-treated steel sheet to be produced.

  As a result of intensive studies to achieve the above object, the present inventors have conducted a cathodic electrolytic treatment on a steel sheet containing a metal oxygen compound in an electrolytic treatment tank comprising a treatment liquid containing metal ions and an electrode. In the case of forming, the roll for sending the steel sheet into the electrolytic treatment tank is an energizing roll electrically connected to a power source for flowing a direct current through the steel sheet, while the steel sheet is pulled up from the electrolytic treatment tank. It has been found that the above object can be achieved by using a non-energizing roll that is not connected to a power source, and the present invention has been completed.

That is, according to the present invention, by using an electrolytic treatment line having a plurality of electrolytic treatment tanks including metal ions containing a treatment liquid and electrodes, a steel plate is continuously fed into each electrolytic treatment tank, Production of a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet by performing electrolytic treatment by flowing a direct current between the steel sheet and the electrode in the treatment tank. A method, wherein the steel plate is provided for each of a plurality of the electrolytic treatment tanks, and a roll for feeding the steel plate into the electrolytic treatment tank, and for lifting the steel plate from the electrolytic treatment tank. The plurality of rolls provided in the electrolytic treatment line are continuously fed into each electrolytic treatment tank constituting the electrolytic treatment line by a roll, and direct current is passed through the steel plate. After the metal oxygen compound is formed by electrolytic treatment on the surface of the steel sheet that is in contact with the roll, the current-carrying roll electrically connected to the power source and the non-energized roll not connected to the power source By providing the energizing roll so that the metal oxygen compound and the energizing roll do not contact with each other, an arc spot is not generated, and a method for producing a surface-treated steel sheet is provided.
Among the plurality of rolls provided in the electrolytic treatment line, a roll for sending a surface in contact with the roll of the steel plate into an electrolytic treatment tank that performs electrolytic treatment first causes a direct current to flow through the steel plate. It may be an energizing roll electrically connected to the power source.

  Further, according to the present invention, by using an electrolytic treatment line having a plurality of electrolytic treatment tanks including metal ions-containing treatment liquid and electrodes, a steel plate is continuously fed into each electrolytic treatment tank, Production of a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet by performing electrolytic treatment by flowing a direct current between the steel sheet and the electrode in the treatment tank. A method, wherein the steel plate is provided for each of a plurality of the electrolytic treatment tanks, and a roll for feeding the steel plate into the electrolytic treatment tank, and for lifting the steel plate from the electrolytic treatment tank. A plurality of rolls, which are continuously fed into the respective electrolytic treatment tanks constituting the electrolytic treatment line by a roll, and are provided in the electrolytic treatment line, allow a direct current to flow through the steel plate. A conductive roll electrically connected to the power source and a non-conductive roll not connected to the power source, and the resistance value of the coating containing the metal oxygen compound on the surface of the steel sheet in contact with the conductive roll and the conductive roll By controlling the applied voltage, there is provided a method for producing a surface-treated steel sheet, wherein an arc spot is not generated when the steel sheet and the energizing roll come into contact with each other.

  Further, according to the present invention, by using an electrolytic treatment line having a plurality of electrolytic treatment tanks including metal ions-containing treatment liquid and electrodes, a steel plate is continuously fed into each electrolytic treatment tank, Production of a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet by performing electrolytic treatment by flowing a direct current between the steel sheet and the electrode in the treatment tank. A method, wherein the steel plate is provided for each of a plurality of the electrolytic treatment tanks, and a roll for feeding the steel plate into the electrolytic treatment tank, and for lifting the steel plate from the electrolytic treatment tank. A plurality of rolls, which are continuously fed into the respective electrolytic treatment tanks constituting the electrolytic treatment line by a roll, and are provided in the electrolytic treatment line, allow a direct current to flow through the steel plate. A conductive roll electrically connected to the power source, and a non-conductive roll not connected to the power source, the resistance value of the coating containing the metal oxygen compound on the surface of the steel sheet in contact with the conductive roll, and the conductive roll The surface-treated steel sheet is characterized in that an arc spot is not generated when the steel sheet and the energizing roll come into contact with each other by controlling the voltage applied to the energizing roll and the number of the energizing rolls to be arranged. A manufacturing method is provided.

  According to the present invention, a steel plate is continuously fed into an electrolytic treatment tank including a treatment liquid containing metal ions and an electrode, and a direct current is applied between the steel plate and the electrode in the electrolytic treatment tank. A method for producing a surface-treated steel sheet, comprising a step of performing an electrolytic treatment by passing an electric current and forming a film containing a metal oxygen compound on the surface of the steel sheet, wherein the steel sheet is placed in the electrolytic treatment tank. A first roll for feeding and a second roll for pulling up the steel plate from the electrolytic treatment tank are continuously fed into the electrolytic treatment tank, and the first roll has a direct current applied to the steel plate. There is provided a method for producing a surface-treated steel sheet, wherein the second roll is a non-energized roll not connected to a power source. .

In the manufacturing method of this invention, it is preferable that the said process liquid contains the ion of at least 1 sort (s) of metal among Zr, Al, and Ti.
In the manufacturing method of this invention, it is preferable that pH of the said processing liquid is 2-5.
In the production method of the present invention, the electric resistance value of the film surface formed on the surface of the steel sheet is preferably 0.1Ω or more, more preferably 0.3Ω or more.
In the production method of the present invention, the molar amount of the metal of the coating to be formed on the surface of the steel sheet is preferably 0.5 mmol / ^{m 2} or more, more preferably 0.7 mmol / ^{m 2} or more.
In the production method of the present invention, the thickness of the film formed on the surface of the steel plate is preferably 15 nm or more.

  Moreover, according to this invention, the surface-treated steel plate for metal cans produced using said manufacturing method is provided.

  According to the present invention, it is possible to increase the thickness of a metal oxygen compound film formed on a metal substrate while preventing the occurrence of appearance defects such as arc spots on the metal substrate, and to produce a surface-treated steel sheet to be produced. The manufacturing method of the surface treatment steel plate which can improve property can be provided.

FIG. 1 is a diagram illustrating an example of a configuration of a surface treatment line according to the present embodiment. FIG. 2 is a diagram illustrating an example of the configuration of the electrolytic treatment tank according to the present embodiment. FIG. 3 is a diagram illustrating an example of a configuration of an electrolytic treatment tank according to a conventional example. FIG. 4 is a diagram illustrating another example of the electrolytic treatment tank according to the present embodiment. FIG. 5 is a view showing still another example of the electrolytic treatment tank according to the present embodiment. FIG. 6 is a diagram illustrating another example of the configuration of the surface treatment line according to the present embodiment. FIG. 7 is a diagram showing still another example of the configuration of the surface treatment line according to the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of a surface treatment line 100 used in the manufacturing method of the present embodiment. The surface treatment line 100 of this embodiment is a line for forming a metal oxygen compound film on the substrate 1, and as shown in FIG. 1, the pickling treatment tank 10, the pickling solution rinse treatment tank 20, the first 1 electrolytic treatment tank 30, second electrolytic treatment tank 40, electrolytic solution rinsing treatment tank 50, carrier rolls 61, 63, 65, 67, 69, 71, and sink rolls 62, 64, 66, 68, 70 are provided. . Of these carrier rolls, the carrier roll 65 used when transporting the substrate 1 to the first electrolytic treatment tank 30 is energized by being electrically connected to an external power source via a rectifier described later. It has a function as a conductor roll that can be energized while transporting the substrate 1. Further, the anodes 80a to 80h shown in FIG. 1 are energized by being electrically connected to an external power source through a rectifier, and the base material 1 is applied to the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40. On the other hand, it acts as an electrode when the electrolytic treatment is performed.

  In this embodiment, the base material 1 is a pickling treatment tank 10, a pickling liquid rinsing treatment tank 20, a first electrolytic treatment tank 30, a second electrolytic treatment tank 40, and the like in the surface treatment line 100 by each carrier roll. And the electrolytic solution rinsing treatment tank 50 in this order, and various treatments are performed in each treatment tank. Specifically, first, the base material 1 is pickled with a pickling solution in the pickling bath 10, and then pickled in the pickling solution rinsing bath 20. The liquid is washed with water. And the base material 1 is the anode 80a-80h in the electrolytic treatment liquid with which the 1st electrolytic treatment tank 30 and the 2nd electrolytic treatment tank 40 were filled in the 1st electrolytic treatment tank 30 and the 2nd electrolytic treatment tank 40. When facing each other, electrolytic treatment is performed by the action of a direct current applied from a power source through the energized carrier roll 65, and a metal oxygen compound film is formed on the surface. Thereafter, the electrolytic treatment liquid adhering to the base material 1 is washed with water in the electrolytic solution rinsing treatment tank 50.

  The base material 1 is not particularly limited. For example, hot-rolled steel sheets based on an aluminum killed steel continuous cast material, etc., and after these hot-rolled steel sheets are pickled to remove surface scales (oxide films), they are cold-worked. A rolled cold-rolled steel sheet, a steel sheet provided with a plating layer containing Zn, Sn, Ni, Cu, Al, or the like on these hot-rolled steel sheets or cold-rolled steel sheets can be used. Moreover, you may use as a base material 1 what these steel plates washed with degreasing water.

  The pickling treatment tank 10 is filled with a pickling treatment liquid, and is a treatment tank for applying a pickling treatment liquid as a pretreatment for electrolytic treatment to the substrate 1. When the base material 1 is sent into the pickling treatment tank 10 by the carrier roll 61, the scale (oxide film) on the surface of the base material 1 is removed by immersing the base material 1 in the pickling treatment liquid. It does not specifically limit as a pickling process liquid, According to the kind of base material 1, the kind of acid, the density | concentration of a pickling process liquid, temperature, etc. can be selected suitably.

  The pickling liquid rinsing treatment tank 20 is a treatment tank for washing the substrate 1 with water, and examples thereof include a tank filled with water. When a tank filled with water is used as the pickling solution rinsing treatment tank 20, when the substrate 1 is sent into the pickling solution rinsing treatment tank 20 by the carrier roll 63, the substrate 1 is immersed in water. As a result, the pickling solution adhering to the surface of the substrate 1 is washed away. Alternatively, the pickling solution rinsing treatment tank 20 may be a facility for spraying water on the base material 1 in order to wash the base material 1 with water. In this case, even if the pickling solution rinsing bath 20 is not filled with water, the pickling solution adhering to the surface of the substrate 1 can be washed away with the sprayed water.

  The first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 are filled with an electrolytic treatment liquid, and are treatment tanks for forming a metal oxygen compound film on the substrate 1 by electrolytic treatment. In the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40, first, when the base material 1 is sent into the first electrolytic treatment tank 30 by the carrier roll 65, the action of the anodes 80a to 80d in the electrolytic treatment liquid. Electrolytic treatment is performed on the substrate 1. Next, the base material 1 is pulled up from the first electrolytic treatment tank 30 by the carrier roll 67 and is sent into the second electrolytic treatment tank 40. Similarly, in the electrolytic treatment liquid, by the action of the anodes 80e to 80h. Electrolytic treatment is performed on the substrate 1. The detailed configuration of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 will be described later.

  The electrolytic solution rinsing treatment tank 50 is a treatment tank for washing the substrate 1 with water, and may be filled with water, or water may be sprayed onto the substrate 1 with a spray device. When the base material 1 is sent into the electrolytic solution rinsing treatment tank 50 by the carrier roll 69, the electrolytic treatment liquid attached to the surface of the base material 1 is washed away when passing through the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40. It is. Alternatively, a plurality of electrolytic solution rinsing treatment tanks 50 may be provided, and the front tank may be washed with an electrolytic treatment liquid, and the latter tank may be washed with water. The electrolytic treatment liquid or water used in the electrolytic solution rinsing treatment tank 50 may be used in a mode in which the electrolytic solution rinsing treatment tank 50 is filled and the substrate 1 is immersed, or in the electrolytic solution rinsing treatment tank 50. You may spray on the base material 1 with the installed spray apparatus. By immersing or spraying in the electrolytic treatment solution before washing with water, an excessive film formed on the substrate 1 can be removed. Further, the electrolytic solution rinsing treatment tank 50 can be additionally provided between the first first electrolytic treatment tank 30 and the last second electrolytic treatment tank 40 for performing the electrolytic treatment.

  Here, FIG. 2 is a diagram showing in detail the configuration of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 shown in FIG. As shown in FIG. 2, the first electrolytic treatment tank 30 is filled with an electrolytic treatment liquid 31, and four anodes 80 a to 80 d are immersed in the electrolytic treatment liquid 31. In addition, carrier rolls 65 and 67 and a sink roll 66 are arranged around and inside the first electrolytic treatment tank 30, respectively.

  The carrier roll 65 is a roll for lifting the base material 1 from the above-described pickling solution rinsing treatment tank 20 and sending it into the first electrolytic treatment tank 30, and is connected to an external power source via a rectifier 90 described later. It is electrically connected and has a function as a conductor roll capable of energizing the substrate 1 while conveying the substrate 1. The sink roll 66 is a roll for changing the traveling direction of the substrate 1 in the electrolytic treatment liquid. The carrier roll 67 is a roll for lifting the substrate 1 from the first electrolytic treatment tank 30 and sending it into the second electrolytic treatment tank 40. The carrier roll 67 is a non-conducting roll that is not connected to a power source, unlike the carrier roll 65 described above.

  Similarly to the first electrolytic treatment tank 30, the second electrolytic treatment tank 40 is also filled with the electrolytic treatment liquid 41, and anodes 80e to 80h are immersed in the electrolytic treatment liquid 41. Carrier rolls 67 and 69 and a sink roll 68 are arranged around and inside the electrolytic treatment tank 40, respectively. The carrier roll 69 is a non-conducting roll that is not connected to a power source, like the carrier roll 67.

  A plurality of rectifiers 90 are installed outside the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40, and the plurality of rectifiers 90 are connected to an external power source (not shown). The plurality of rectifiers 90 are electrically connected to the anodes 80a to 80h immersed in the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40, whereby each anode is energized. When the electrolytic treatment is performed, the base material 1 acts as an oxidation electrode (electrode from which electrons are extracted).

  All the rectifiers 90 connected to the respective anodes are also electrically connected to the carrier roll 65. As a result, the carrier roll 65 is energized and functions as a conductor roll that can pass a current through the substrate 1 while conveying the substrate 1. Therefore, the base material 1 is energized by the carrier roll 65 and is sent to the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 by the respective carrier rolls in the energized state, so that the electrolytic treatment is performed by the action of the anodes 80a to 80h. And a metal oxygen compound film is formed on the substrate 1.

  The anodes 80a to 80h are preferably made of an insoluble metal such as platinum or stainless steel, or a coating metal such as titanium on which iridium oxide is deposited, because of high electrochemical stability. The rectifier 90 is not particularly limited, and a known rectifier can be used according to the magnitude of power supplied to the carrier roll 65 and the anodes 80a to 80h.

  The electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 are aqueous solutions containing metal ions for forming a metal oxygen compound film formed on the substrate 1. Here, from the point that the metal ion contained in the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 can satisfactorily form a metal oxygen compound film on the substrate 1, among Zr, Al, and Ti, At least one metal ion is preferable, and Zr is particularly preferable. If such an electrolytic treatment solution continues to be used for the electrolytic treatment, the amount of impurities in the electrolytic treatment solution increases and the efficiency and quality of the electrolytic treatment deteriorates. The electrolytic treatment may be performed while appropriately circulating the liquid. For example, a larger amount of electrolytic treatment liquid 31 than the capacity of the first electrolytic treatment tank 30 is prepared in advance, and a part of the prepared electrolytic treatment liquid 31 is disposed outside the first electrolytic treatment tank 30. It may be put in (not shown) and the electrolytic treatment may be performed while circulating between the treatment liquid tank and the first electrolytic treatment tank 30 by a pump or the like. Similarly, the second electrolytic treatment tank 40 may be configured to circulate the electrolytic treatment liquid 41.

  In the present embodiment, by using the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 as described above, the base material 1 is subjected to electrolytic treatment as follows, and the metal oxygen compound film is formed on the base material 1. It is formed.

  That is, first, the base material 1 is fed into the first electrolytic treatment tank 30 by the carrier roll 65 and is immersed in the electrolytic treatment liquid 31 in the electrolytic treatment liquid 31 of the first electrolytic treatment tank 30. It is conveyed between 80b. The base material 1 is subjected to cathodic electrolysis by the action of a direct current applied from a power source via the energized carrier roll 65 while facing the anodes 80a and 80b when passing between the anodes 80a and 80b. A metal oxygen compound film is formed on the surface.

  Specifically, in cathodic electrolysis, when current flows between the base material 1 and the anodes 80a and 80b, water in the electrolysis solution 31 is electrolyzed near the surface of the base material 1 to generate hydrogen. As a result, the pH in the vicinity of the surface of the substrate 1 is increased, and the metal ions contained in the electrolytic treatment liquid 31 are precipitated as oxygen compounds due to the increase in pH. A metal oxygen compound film is formed. For example, when the electrolytic treatment solutions 31 and 41 contain Zr ions, a metal oxygen compound film containing a Zr oxygen compound is formed on the substrate 1. Similarly, when the electrolytic treatment liquids 31 and 41 contain, for example, Al ions, a metal oxygen compound film containing Al oxygen compounds is formed on the substrate 1 and further contains Ti ions. In this case, a metal oxygen compound film containing an oxygen compound of Ti is formed on the substrate 1.

  The base material 1 is subjected to cathodic electrolysis by the action of the anodes 80a and 80b, and then the direction of travel is changed by the sink roll 66, so that the anodes 80c and 80d face each other in the electrolysis liquid 31. Again, cathodic electrolysis is performed, and a metal oxygen compound film is further formed on the substrate 1. Next, the substrate 1 is pulled up from the first electrolytic treatment tank 30 by the carrier roll 67 and is sent into the second electrolytic treatment tank 40. The base material 1 is similarly subjected to cathodic electrolysis treatment by the action of the anodes 80e and 80f in the electrolysis treatment solution 41 of the second electrolysis treatment tank 40, and then cathodic electrolysis treatment by the action of the anodes 80g and 80h. And a metal oxygen compound film is further formed on the substrate 1. Thereafter, the substrate 1 is pulled up from the second electrolytic treatment tank 40 by the carrier roll 69. In this embodiment, the electrolytic treatment for the base material 1 by the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 is performed in this manner.

  In the present embodiment, as shown in FIG. 2, the first electrolysis tank 30 and the second electrolysis tank 40 are formed by using the carrier roll 65 as a conductive roll, while using the carrier rolls 67 and 69 as a non-conductive roll. Use to form a metal oxygen compound film on the substrate 1. Therefore, when forming a metal oxygen compound film on the base material 1 as described below, the voltage applied to the carrier roll is suppressed, and appearance defects such as discharge traces (arc spots) generated on the base material 1 are generated. Can be prevented. In addition, although the case where the electrolytic treatment tank was two tanks was shown as an example of this embodiment, the effect of the present invention can be obtained even if the number of electrolytic treatment tanks is three or more for the purpose of obtaining a necessary coating amount. .

  That is, first, since the metal oxygen compound film formed by the electrolytic treatment is an insulating film, a direct current is applied to the substrate 1 on which the metal oxygen compound film is formed thick using an energized conductor roll. In this case, an excessive voltage is applied to the conductor roll. In this case, the metal oxygen compound film exfoliation formed on the base material 1 or the electrolytic treatment liquid deposit may be deposited on the conductor roll, and an excessive voltage is applied to the conductor roll. If so, high-voltage discharge locally occurs on the conductor roll due to the unevenness caused by such deposits, thereby causing appearance defects such as arc spots on the substrate 1. There's a problem.

  Here, since the carrier rolls 67 and 69 are rolls for transporting the base material 1 on which the metal oxygen compound film is formed, if the carrier rolls 67 and 69 are conductive rolls energized, the carrier roll 67 , 69 may be applied with an excessive voltage, and an arc spot may be generated on the substrate 1. In particular, the carrier roll 69 is a roll that conveys the base material 1 on which a thicker metal oxygen compound film is formed as compared with the carrier roll 67, and is applied to the base material 1 through such a thick metal oxygen compound film. In order to energize, it is necessary to apply a higher voltage. Therefore, in the carrier roll 69, the problem of the arc spot in the base material 1 becomes remarkable.

  On the other hand, in this embodiment, since the carrier rolls 67 and 69 are not energized, an excessive voltage is applied to the carrier rolls 67 and 69 even when the substrate 1 on which the metal oxygen compound film is formed is transported. Is not applied. Therefore, even when a metal oxygen compound film or the like is deposited on the carrier rolls 67 and 69 and unevenness is formed on the surface, local high voltage discharge does not occur, and an arc spot is generated in the substrate 1. It can be effectively prevented.

  In addition, as a method of forming a metal oxygen compound film on the substrate 1 by electrolytic treatment, conventionally, as shown in FIG. 3, as a conductor roll in which all the carrier rolls arranged around the electrolytic treatment tank are energized, A method of performing electrolytic treatment is used. The first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 shown in FIG. 3 are the same as in FIG. 2 except that the carrier rolls 65, 67a, and 69a are conductive rolls. 41, sink rolls 66 and 68, anodes 80a to 80h, and a rectifier 90.

  In such a configuration shown in FIG. 3, when the base material 1 is energized from the carrier rolls 67a and 69a, as described above, an excessive voltage is applied to the carrier rolls 67a and 69a, and the carrier roll 67a. , 69a, a metal oxygen compound film or the like is deposited and irregularities are formed on the surface, which may cause an arc spot on the substrate 1. In particular, since the carrier roll 69a is a roll for transporting the base material 1 on which a thicker metal oxygen compound film is formed compared to the carrier roll 67a, when energizing the base material 1 from the carrier roll 69a, Further, an excessive voltage is applied, and the problem of such an arc spot becomes remarkable. In addition, in the carrier roll 69a, there is a problem that the carrier roll 69a is damaged due to application of an excessive voltage, or a problem that a maintenance needs to be performed whenever a local high-voltage discharge occurs. There is also. Conventionally, metal oxygen compound coatings have been studied in a range where the coating amount is small, and no problems with these energization methods have occurred. However, depending on the application of the surface-treated steel sheet such as improvement of the resistance to contents of metal cans, it has become necessary to further increase the amount of coating. In this case, the problem related to the energization method becomes remarkable, which is a big problem in terms of productivity and quality.

  Furthermore, the rate at which the metal oxygen compound film is formed by the electrolytic treatment is such that the pH in the vicinity of the surface of the base material 1 when hydrogen is generated by electrolyzing water in the electrolytic processing solution in the vicinity of the surface of the base material 1. It depends on the ascending speed. Therefore, in order to increase the speed at which the metal oxygen compound film is formed on the substrate 1, it is necessary to apply a high voltage to the roll in order to cause electrolysis of water, and the speed at which the metal oxygen compound film is formed is increased. As the metal oxygen compound film becomes thicker, such a problem becomes more prominent.

  On the other hand, in this embodiment, as shown in FIG. 2, the carrier roll 65 is a conductive roll, and the carrier rolls 67 and 69 are non-conductive rolls. A metal oxygen compound film is formed on the substrate 1 using the treatment tank 40. In particular, in the present embodiment, the carrier roll 65 is a conductive roll, while the carrier rolls 67 and 69 are not energized. Therefore, the base material 1 on which the metal oxygen compound film is formed by the carrier rolls 67 and 69. Even when the sheet is conveyed, an excessive voltage is not applied to the carrier rolls 67 and 69. Therefore, even when a metal oxygen compound film or the like is deposited on the carrier rolls 67 and 69 and unevenness is formed on the surface, local high-voltage discharge does not occur on the carrier rolls 67 and 69, and the substrate 1 can effectively prevent the occurrence of arc spots.

  As described above, according to the manufacturing method of the present embodiment, it is possible to increase the thickness of the metal oxygen compound film formed on the base material 1 while preventing appearance defects such as arc spots on the base material 1. And In addition, according to the manufacturing method of the present embodiment, since an excessive voltage is not applied to the carrier roll, the carrier roll can be prevented from being damaged and the frequency of maintenance of the carrier roll can be reduced. Productivity of the treated steel sheet can be improved.

  When a surface-treated steel sheet produced by forming a metal oxygen compound film on the substrate 1 is used as a material for a seamless can or a three-piece can, an organic resin layer is further formed on the surface-treated steel sheet. It will be processed into the shape. In producing seamless cans and three-piece cans, surface-treated steel plates are subjected to various forces such as tension and compression by drawing, drawing and ironing, necking, flange processing, and the like. In addition, even after making cans, it is difficult for metal surfaces to be filled with food and beverages and subjected to heat treatment such as retort processing, and for contents such as coffee to be stored in a vendor-heated state. Will be placed in a different situation. Therefore, when using such a surface-treated steel sheet for cans, it is necessary to suppress cracking of the metal oxygen compound film and suppress the exposure of the steel sheet of the base 1 as much as possible. When the suppression of the exposure of the steel plate of the base material 1 is not sufficient, the seamless can and the three-piece can easily peel off the organic resin layer in the portion where the steel plate of the base material 1 is exposed, and the content resistance (corrosion resistance) decreases. In addition, on the outer surface side of the can, a decrease in print appearance quality is induced. In particular, when the suppression of the exposure of the steel sheet of the base material 1 is not sufficient, when the can filled with the contents and stored after the retort sterilization treatment is subjected to can deformation such as a drop impact, and further stored over time, The organic resin layer tends to be peeled off, and the content resistance (corrosion resistance) is lowered and the printed appearance quality on the outer side of the can is significantly lowered.

  On the other hand, according to the manufacturing method of this embodiment, since the metal oxygen compound film formed on the base material 1 can be thickened, the obtained surface-treated steel sheet is used for manufacturing seamless cans and three-piece cans. Even if it is a case, it becomes possible to manufacture the can which suppressed the exposure of the base material 1 and was excellent in content resistance (corrosion resistance) and printed appearance.

  According to this embodiment, the thickness of the metal oxygen compound film formed on the substrate 1 can be increased to preferably 15 nm or more, more preferably 25 nm or more, and thereby the surface to be obtained. When the treated steel plate is applied as a metal can, excellent content resistance (corrosion resistance) and printed appearance can be imparted.

Furthermore, suitable amount of the coating film as the metal oxygen compound film is in a molar amount of metal contained in the metal oxygen compound film is preferably 0.5 mmol / ^{m 2} or more, more preferably 0.7 mmol / ^{m 2} or more. Illustratively, the coating amount of the metal oxygen compound film is preferably about 46 mg / m ² or more, more preferably about 64 mg / m ² or more, and only Al when the metal oxygen compound consists of only Zr. If made of, by weight film thickness, preferably from about 14 mg / ^{m 2} or more, more preferably about 19 mg / ^{m 2} or more, if made of Ti alone, by weight film thickness, preferably from about 24 mg / ^{m 2} As described above, more preferably about 34 mg / m ² or more. Of course, the metal oxygen compound may be a mixture of two or more of Zr, Al, and Ti.
In a molar amount of metal contained in the metal oxygen compound film, when preferably 0.5 mmol / ^{m 2} or more, more preferably applied by a 0.7 mmol / ^{m 2} or more, the surface treated steel sheet obtained as metal cans Excellent content resistance (corrosion resistance) and printed appearance.

  The electrical resistance suitable for the metal oxygen compound film is preferably 0.1Ω or more, more preferably 0.3Ω or more. By making the electrical resistance of the surface of the metal oxygen compound film within the above range, the resulting surface-treated steel sheet has excellent insulation properties, and imparts excellent content resistance (corrosion resistance) and printed appearance when applied as a metal can. can do.

  In the above-described embodiment, a configuration in which the carrier roll 65 is an energized conductor roll and the carrier rolls 67 and 69 are non-energized rolls is illustrated. However, for example, as illustrated in FIG. The carrier roll, which is a roll for lifting the substrate 1 from the first electrolytic treatment tank 30 and transporting it to the second electrolytic treatment tank 40, is shown as an energized conductor roll (indicated by reference numeral “67a” in FIG. 4). .). In the case where there are a plurality of electrolytic treatment tanks, if only one conductor roll is energized, the carrier roll 65 will carry the entire current necessary for the electrolytic treatment. If the current becomes too high, the generation of an arc spot or the plating on the roll surface may be peeled off even in the carrier roll 65 due to the introduction of foreign matters from the previous process, and surface defects of the surface-treated steel sheet may occur. Therefore, these problems can be avoided by making the carrier roll 67a a conductive roll as necessary. In that case, the value of the current flowing through the carrier roll 67a may be adjusted according to the actual operation. For example, the amount of the metal oxygen compound film formed according to the current value, that is, the anode through the carrier roll 67a. The amount of the metal oxygen compound film formed in accordance with the value of the current flowing through 80a and 80d may be set so as not to generate an arc spot when the metal oxygen compound film contacts the carrier roll 67a. Further, by installing a spray facility or a squeeze roll between the electrolytic treatment liquid surface and the carrier roll 67a or 69, the excess film formed on the substrate 1 is reduced, and the generation of the arc spot is suppressed. You can also play a role.

  According to the configuration shown in FIG. 4, the energization of the base material 1 is performed by the carrier rolls 65 and 67a, respectively. Here, since the carrier roll 67a is a roll for transporting the base material 1 on which the metal oxygen compound film is formed, a large voltage is applied when the base material 1 is energized through such a metal oxygen compound film. Will be applied. However, when the base material 1 reaches the carrier roll 67a, since the base material 1 is in a state before being subjected to the electrolytic treatment by the second electrolytic treatment tank 40, the metal formed on the base material 1 The oxygen compound film is relatively thin, and the voltage necessary for energizing the substrate 1 from the carrier roll 67a shown in FIG. 4 is the voltage necessary for energizing the substrate 1 from the carrier roll 69a shown in FIG. It becomes small compared with.

  Therefore, as shown in FIG. 4, when the carrier rolls 65 and 67 a are conductive conductors and the carrier roll 69 is a non-conductive roll, the metal formed on the substrate 1 in the first electrolytic treatment tank 30. Depending on the thickness of the oxygen compound film and the magnitude of the current flowing through the carrier roll 67a, an excessive voltage can be prevented from being applied to the carrier roll 67a, and the applied voltage can be reduced. As a result, excessive voltage is not applied to each carrier roll on the carrier roll 67a, and local discharge occurs, thereby preventing appearance defects such as arc spots from occurring on the substrate 1. It is possible to effectively prevent the appearance defects such as the generated arc spot. Therefore, in the present embodiment, even when an electrolytic treatment tank having a configuration as shown in FIG. 4 is used, it is formed on the substrate 1 while preventing appearance defects such as arc spots on the substrate 1 from occurring. The thickness of the metal oxygen compound film can be increased, and in addition, the productivity of the manufactured surface-treated steel sheet can be improved.

In the present embodiment, as shown in FIG. 5, two anodes of the first electrolytic treatment tank 30 are arranged on the side not in direct contact with the carrier roll 67a, and the anode of the second electrolytic treatment tank 40 is set to 4 as usual. In this arrangement, the carrier rolls 65 and 67a may be conductive conductor rolls, and the carrier roll 69 may be a non-conductive roll.
Further, as another example of the form in which the anode is arranged as in FIG. 5, it is possible to use only the carrier roll 67a as a conductive roll and the carrier rolls 65 and 69 as non-conductive rolls.

  In particular, in the present embodiment, as shown in FIG. 5, after the metal oxygen compound film is formed on the surface of the substrate 1 in contact with each carrier roll (hereinafter referred to as carrier roll surface), the metal oxygen compound film is formed. In addition, it is possible to appropriately prevent occurrence of defective appearance such as an arc spot by adopting a configuration that prevents contact with the energized conductor roll. That is, in the configuration shown in FIG. 5, since the anodes 80b and 80c are arranged on the opposite side of the carrier roll surface of the substrate 1, the substrate 1 passes through the first electrolytic treatment tank 30 and becomes the carrier roll 67a. When reaching, it is possible to relatively reduce the amount of the metal oxygen compound film formed on the surface of the substrate 1 in contact with the carrier roll 67a, thereby applying an excessive voltage to the carrier roll 67a. It is possible to prevent the occurrence of appearance defects such as arc spots.

  In addition, in the structure shown in FIG. 5, since the carrier roll 67a for sending to the electrolytic treatment tank (2nd electrolytic treatment tank 40) which electrolyzes the carrier roll surface of the base material 1 first is made into the electrically-conductive conductor roll. The current is transmitted well from the carrier roll 67a adjacent to the second electrolytic treatment tank 40 to the base material 1 in the second electrolytic treatment tank 40, and the electrolytic treatment is efficiently performed in the second electrolytic treatment tank 40. Become.

  Furthermore, in the above-described embodiment, the configuration in which the base material 1 is subjected to electrolytic treatment using the two electrolytic treatment tanks of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 is illustrated. As shown in FIG. 6, the substrate 1 may be subjected to electrolytic treatment using the first electrolytic treatment tank 30 alone without using the second electrolytic treatment tank 40. In this case, as shown in FIG. 7, the number of anodes provided in the first electrolytic treatment tank 30 may be reduced to have two anodes.

  Alternatively, in the surface treatment line 100 shown in FIG. 1 described above, an example in which the two electrolytic treatment tanks of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 are provided is shown. The number of electrolytic treatment tanks provided in is not particularly limited, and may be more than two. Moreover, in the surface treatment line 100 shown in FIG. 1, although the pickling process tank 10, the pickling liquid rinse process tank 20, and the electrolyte solution rinse process tank 50 were each shown, the surface was shown. The numbers of the pickling treatment tank 10, the pickling solution rinsing treatment tank 20, and the electrolytic solution rinsing treatment tank 50 provided in the treatment line 100 are not particularly limited, and may be two or more, respectively.

In the present embodiment, the metal compound constituting the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 is not particularly limited. However, when the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 contain Zr ions. , for _example, K ₂ ZrF _6, or the like can be used _{(NH 4) 2 ZrF 6,} (NH 4) 2 ZrO (CO 3) 2, ZrO (NO 3) 2, ZrO (CH 3 COO) 2. When Al ions are included, for example, Al (NO ₃ ) ₃ · 9H ₂ O, AlK (SO ₄ ) ₂ · 12H ₂ O, Al ₂ (SO ₄ ) ₃ · 13H ₂ O, Al ( H ₂ PO ₄ ) ₃ , AlPO ₄ , [CH ₃ CH (OH) COO] ₃ Al, or the like can be used. When Ti ions are included, for example, K ₂ TiF ₆ , (NH ₄ ) ₂ TiF ₆ , Na ₂ TiF ₆ , K ₂ TiO (C ₂ O ₄ ) ₂ .2H ₂ O, TiCl ₃ , TiCl ₄ or the like can be used. In the present embodiment, for the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41, the above-described compounds may be used alone or in combination of two or more. The electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 may be the same aqueous solution, but may be prepared using different metal compounds, or the same metal oxygen compound may be blended differently. It may be blended in a ratio.

  In addition, the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 contain a complexing agent such as fluoride or cyanide in order to enhance the solubility of metal ions such as Zr, Al, or Ti in the liquid. May be. The concentrations of the metal ions and the complexing agent contained in the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 are not particularly limited, and adjustment of conductivity and current density in the treatment liquid and the amount of formation of the metal oxygen compound film It can set suitably for adjustment of this.

  Alternatively, the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 may be added with an electrolyte such as nitrate ion or ammonium ion within a range not inhibiting the formation of the metal oxygen compound film in order to improve the conductivity in the treatment liquid. Good.

  Moreover, the pH of the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41 is preferably 2.0 to 5.0, more preferably 2.5 to 4.0. If the pH is too low, the surface of the substrate 1 will be etched too much, and it will be difficult to form a metal oxygen compound film. On the other hand, if the pH is too high, unnecessary metal oxygen compounds are precipitated in the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41, and the deposition of the metal oxygen compounds on the substrate 1 tends to be inhibited. .

  Alternatively, an organic acid such as polyacrylic acid, polyitaconic acid, citric acid, lactic acid, tartaric acid, glycolic acid, phenol resin, or hydroxy acid may be added to the electrolytic treatment liquid 31 and the electrolytic treatment liquid 41. By adding such an organic acid, when an organic resin layer is formed on the metal oxygen compound film, the adhesion between the metal oxygen compound film and the organic resin layer can be improved. In addition, such an organic resin layer is formed on a metal oxygen compound film, for example, when using the surface treatment steel plate which formed the metal oxygen compound film on the surface as a material of a seamless can or a three-piece can.

  Moreover, although each carrier roll with which the surface treatment line 100 shown in FIG. 1 was comprised was comprised with one roll, even if each carrier roll was comprised with two or more rolls, Good. For example, for lifting the substrate 1 from the first electrolytic treatment tank 30 and for raising the substrate 1 from the first electrolytic treatment tank 30 with respect to the carrier roll 67 that is a roll for sending it into the second electrolytic treatment tank 40. The roll and the roll for feeding the base material 1 into the second electrolytic treatment tank 40 may be composed of separate rolls. The material of each carrier roll is not particularly limited. For example, the carrier roll that is a non-conducting roll may be a material that exhibits electrical insulation, such as rubber.

  Furthermore, each carrier roll removes a nip roll for pressing the base material 1 when the base material 1 is conveyed and various processing liquids adhering to the surface of the base material 1 on the side not facing the carrier roll. Ringer rolls for preventing the processing liquid from being taken out may be provided.

<Manufacture of surface-treated steel sheets for metal cans>
The surface-treated steel sheet produced by the production method of the present invention can be used as a member constituting a metal can (surface-treated steel sheet for metal can). As described above, it is important to suppress the exposure of the steel sheet of the base material 1 as the surface-treated steel sheet for metal cans.
That is, as a surface-treated steel sheet for metal cans, a surface-treated steel sheet having a metal oxygen compound film containing at least one metal ion of Zr, Al, and Ti,
1. 1. The thickness of the film is preferably 15 nm or more, more preferably 25 nm or more and 160 nm or less. In a molar amount of metal contained in the metal oxygen compound film, it preferably 0.5 mmol / ^{m 2} or more, more preferably 4.4 mmol / ^{m 2} or less there is 0.7 mmol / ^{m 2} or more 3. The electrical resistance of the metal oxygen compound film is preferably 0.1Ω or more, more preferably 0.3Ω or more and 3500Ω or less.
By satisfying at least one of the above 1 to 3, it is possible to impart excellent content resistance (corrosion resistance) and printed appearance when the obtained surface-treated steel sheet is applied as a metal can. If the metal oxygen compound film is too thick, the film is cracked and the adhesion is deteriorated during can molding, neck processing, flange processing, etc., and therefore there is a suitable range for the film thickness.

<Manufacture of organic resin-coated surface-treated steel sheet for metal cans>
When a surface-treated steel sheet produced using the production method of the present invention is applied to a metal can, it is a member formed by coating the surface-treated steel sheet with an organic resin layer by forming an organic resin layer on the surface. It is preferable to prepare an organic resin-coated surface-treated steel sheet for metal cans and use this as a member of a metal can. The organic resin layer is not particularly limited, and examples thereof include a thermoplastic resin coating layer made of various thermoplastic resins, and a coating film made of a thermosetting paint or a thermoplastic paint. It is also possible to provide a conventionally known adhesion primer or adhesive between the treated steel plate and the organic resin layer.

  Of these, the organic resin layer is preferably a thermoplastic resin coating layer made of a polyester resin suitable for container materials. The polyester resin may be homopolyethylene terephthalate or a copolyester. Or a blend thereof. When the organic resin layer is a thermoplastic resin coating layer, the thermoplastic resin coating layer may be a single resin layer or a multilayer resin layer by coextrusion or the like, Moreover, when it is set as a multilayer, resin which comprises each layer may differ, and the same thing may be sufficient as it. When a multilayer polyester resin layer is used to constitute the thermoplastic resin coating layer, a polyester resin having a composition with excellent adhesiveness is selected on the base layer, that is, the surface-treated steel sheet side, and content resistance, that is, extraction resistance is selected on the surface layer This is advantageous because a polyester resin having a composition excellent in properties and non-adsorption of flavor components can be selected.

  Furthermore, the thickness of the organic resin layer provided on the surface-treated steel sheet is desirably 3 to 50 μm, particularly 5 to 40 μm in general for the thermoplastic resin coating layer. Is preferably in the range of 1 to 50 μm, particularly 3 to 30 μm. When the thickness is less than the above range, the corrosion resistance becomes insufficient, and when the thickness exceeds the above range, a problem is likely to occur in terms of workability.

  Formation of the organic resin layer on the surface-treated steel sheet can be performed by any conventionally known method. For example, when a thermoplastic resin coating layer is formed as the organic resin layer, it can be performed by any means such as an extrusion coating method, a cast film thermal bonding method, a biaxially stretched film thermal bonding method, or the like.

<Production of metal cans>
The organic resin-coated surface-treated steel plate for metal cans produced using the production method of the present invention can be suitably used for three-piece cans (welded cans) having side seams, seamless cans (two-piece cans), and the like. Seamless cans are drawn, drawn and re-squeezed, bent and stretched by drawing and redrawing (stretching), drawn and redrawed by drawing and redrawing, or drawn so that the organic resin layer is on the inner surface of the can.・ Manufactured by means of conventionally known means such as ironing, but especially in seamless cans, bending / stretching by drawing / redrawing (stretching), drawing by redrawing, bending by drawing / redrawing, etc. It can be most suitably used for seamless cans using stretching and ironing.
That is, the organic resin-coated surface-treated steel sheet for metal cans is excellent in work adhesion, so that even when subjected to advanced processing, the organic resin layer has excellent adhesion and excellent corrosion resistance. Can be provided.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, as shown in FIG. 5, after the metal oxygen compound film is formed on the surface (carrier roll surface) in contact with each carrier roll of the substrate 1, However, it may be configured such that the metal oxygen compound film and the energized conductor roll are brought into contact with each other. In this case, the conductive roll is formed on the carrier roll surface of the substrate 1. By appropriately controlling the electrical resistance value of the formed metal oxygen compound film, the voltage applied to the energized conductor roll, and the number of conductor rolls to be arranged, the construction of preventing arc spots from occurring be able to.

  Here, the lower the electrical resistance value of the metal oxygen compound film formed on the carrier roll surface of the base material 1, the higher the local high-voltage discharge on the conductor roll when the base material 1 and the conductor roll are in contact with each other. Occurrence and arc spots resulting from this tend to be less likely to occur. Furthermore, the lower the voltage applied to the conductor roll, the more local high-voltage discharge occurs on the conductor roll and the arc spot due to this when the substrate 1 and the conductor roll come into contact with each other. It tends to be difficult. Therefore, in this embodiment, it is good also as a structure which prevents generation | occurrence | production of an arc spot by balancing the electrical resistance value of such a metal oxygen compound membrane | film | coat, and the voltage applied to a conductor roll.

  In particular, in this embodiment, the electrical resistance value of the metal oxygen compound film usually depends on the thickness of the metal oxygen compound film formed on the substrate 1. Therefore, for example, when the thickness of the metal oxygen compound film is relatively thin, the voltage applied to the conductor roll is relatively high. On the other hand, when the thickness of the metal oxygen compound film is relatively large, the voltage is applied to the conductor roll. The voltage to be controlled may be controlled to be relatively low. In the case where a plurality of conductor rolls are provided, the voltage of the conductor roll in contact with the substrate 1 on which the relatively thin metal oxygen compound film is formed is relatively high, and the base on which the relatively thick metal oxygen compound film is formed. What is necessary is just to control so that the voltage of the conductor roll which contacts the material 1 may be made comparatively low. Furthermore, in this case, even when the voltage applied to the conductor roll is controlled, the current of the energized conductor roll is adjusted so that the film of the metal oxygen compound film formed on the substrate 1 by the electrolytic treatment has a desired thickness. It is preferable to increase or decrease the number. That is, for example, when the voltage applied to the conductor roll is set low, the metal oxygen compound film formed on the base material 1 by electrolytic treatment is increased by increasing the number of energized conductor rolls accordingly. This film can have a desired thickness.

  That is, according to this embodiment, the electric resistance value of the metal oxygen compound film, the voltage applied to the energized conductor roll, and the number of conductor rolls to be arranged are appropriately controlled as described above. Spot generation can be effectively prevented.

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
In the following description, the carrier roll 65 is appropriately referred to as “first roll”, the carrier rolls 67 and 67a as “second roll”, and the carrier rolls 69 and 69a as “third roll”.

Example 1
A cold-rolled steel plate (thickness 0.2 mm, width 200 mm) was prepared as an original plate.
The prepared steel sheet was electrolytically degreased, washed with water, and then subjected to cathodic electrolysis using a surface treatment line 100 shown in FIG. As the cathodic electrolytic treatment, first, the steel plate is fed into the pickling treatment tank 10 by the carrier roll 61 and pickled with sulfuric acid filled in the pickling treatment tank 10, and then pickled by the carrier roll 63. The pre-treatment was carried out by pulling up from the pickling solution and sending it into the pickling solution rinsing bath 20 and washing with water filled in the pickling solution rinsing bath 20. Next, the steel sheet was sent to the first electrolytic treatment tank 30 by the carrier roll 65 (first roll), and the cathode 80 was subjected to cathode electrolytic treatment by the action of the anodes 80a, 80b, 80c, and 80d to form a metal oxygen compound film. . At this time, the steel sheet is conveyed by each carrier roll and energized by a carrier roll 65 (first roll) electrically connected to the power source.

The cathodic electrolysis in the first electrolytic treatment tank 30 is performed by using a treatment liquid tank (not shown) in which 1500 L of the electrolytic treatment liquid 31 is installed outside the first electrolytic treatment tank 30 by a pump. While circulating between the first electrolytic treatment tank 30 having a capacity of 250 L, the line speed (moving speed of the steel sheet): 10 m / min, the number of cycles: 2 times, the energizing time per cycle: 1.2 seconds, The total amount of electricity flowing was 10 C / dm ² and the amount of current to the carrier roll 65 (first roll) was 70 A. A metal oxygen compound film was formed on the steel sheet. Note that the number of cycles indicates the number of times that the steel plate is subjected to electrolytic treatment (in this embodiment, the anode 80a or 80b and 80c or 80d per side, and two electrolytic treatments when passing through the anode. Is performed, the number of cycles is two).
Composition of electrolytic treatment solution: aqueous solution obtained by dissolving ammonium zirconium fluoride as a Zr compound and having a Zr concentration of 6000 ppm by weight and an F concentration of 7000 ppm by weight pH of the electrolytic treatment solution: 3.0
Electrolytic solution temperature: 40 ° C

  Next, the steel plate is subjected to electrolytic treatment to form a metal oxygen compound film, and then the steel plate is pulled up from the first electrolytic treatment tank 30 by the carrier roll 65 (first roll) and sent to the electrolytic solution rinsing treatment tank 50 to obtain the electrolytic solution. The surface-treated steel sheet was obtained by washing with water filled in the rinsing tank 50.

  At this time, the current value flowing through the carrier roll (first roll or second roll) was measured with a clamp meter. The results are shown in Table 1.

  Subsequently, the following evaluation was performed about the surface treatment steel plate obtained in this way.

<Evaluation of presence or absence of arc spot>
After the surface-treated steel sheet was washed with water and dried with a hot air dryer, the surface of the surface-treated steel sheet was visually observed, and the presence or absence of an arc spot was confirmed according to the following criteria. The results are shown in Table 1.
○: An arc spot was not confirmed.
X: An arc spot was generated.

<Measurement of coating amount of metal oxygen compound coating>
For the surface of the surface-treated steel sheet, the amount of Zr deposited is measured by a fluorescent X-ray analyzer (manufactured by Rigaku Corporation, model number: ZSX100e), and the amount of Zr deposited is obtained as the coating amount or molar amount of the metal oxygen compound film It was. The results are shown in Table 1.

<Measurement of thickness of metal oxygen compound film>
The thickness of the metal oxygen compound film was measured by TEM observation. After carbon deposition was performed on the surface of the surface-treated steel sheet, carbon was further deposited by about 1 μm in a FIB apparatus, and a sample was cut out by a microsampling method and fixed on a Cu support. Thereafter, a cross-sectional TEM sample was prepared by FIB processing, TEM observation was performed, the thickness of the coating was measured at three points, and the average value was taken as the thickness.

<Measurement of electrical resistance of surface-treated steel sheet>
For the surface of the surface-treated steel sheet, the electrical resistance value when the terminal is brought into contact with a load of 100 g by a four-terminal method is measured five times using an electric contact simulator (manufactured by Yamazaki Seiki Laboratory Co., Ltd., model number: CSR-1). The average value of the three measurement results excluding the maximum value and the minimum value was calculated. The results are shown in Table 1.

<Measurement of deposition amount of metal oxygen compound on carrier roll>
About the carrier roll 67 (2nd roll) used when producing a surface treatment steel plate, the weight of the deposit (oxygen compound of Zr) adhering to the roll surface was measured, and the following references | standards evaluated. In addition, the weight of the deposit is converted per 1000 cm ² of the surface area of the roll, and the method for collecting the deposit is not particularly limited.
The results are shown in Table 1.
○: The weight of the deposit is less than 0.5 g Δ: The weight of the deposit is 0.5 g or more and less than 1 g ×: The weight of the deposit is 1 g or more

<< Examples 2 and 3 >>
Except that the total amount of electricity flowing through the steel plate and the amount of current to the carrier roll 65 (first roll) when the electrolytic treatment is performed on the steel plate are as shown in Table 1, it is the same as in Example 1. A surface-treated steel sheet was obtained and evaluated in the same manner. The results are shown in Table 1.

Example 4
In Example 4, a surface-treated steel sheet was produced using the surface treatment line 100 shown in FIGS. In Example 4, the same electrolytic treatment liquids 31 and 41 of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 were used as in Example 1 described above, and also in Examples 4 to 6, The electrolytic treatment was performed while circulating the electrolytic treatment solutions 31 and 41, respectively.

In the electrolytic treatment in Example 4, the steel plate is conveyed by each carrier roll, and in the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40, the line speed (moving speed of the steel sheet): 10 m / min, the number of cycles: 4 times. Energizing time per cycle: 1.2 seconds, total amount of electricity flowing through the steel plate: 17 C / dm ² , current amount to the carrier roll 65 (first roll): 110 A. A metal oxygen compound film was formed. In Example 4, the number of cycles, which is the number of times the steel plate is subjected to electrolytic treatment by the anode, was set to 4 (in this example, “Anode 80a, 80b”, “Anode 80c, 80d”, “Anode 80e, 80f "and" Anode 80g, 80h "because four sets of anodes are subjected to electrolytic treatment once, for a total of four times.)

  And after forming a metal oxygen compound membrane | film | coat on a steel plate by electrolytic treatment, the steel plate was washed with water in the electrolyte rinse treatment tank 50, the surface-treated steel plate was obtained, and it evaluated similarly to Example 1. FIG. In Example 4, the measurement of the amount of metal oxygen compound deposited on the carrier roll was carried out by depositing the roll surface for each of the two carrier rolls, carrier roll 67 (second roll) and carrier roll 69 (third roll). The total value of the weight of the product (oxygen compound of Zr) was measured (the same applies to Examples 5 and 6 described later). The results are shown in Table 1.

<< Examples 5 and 6 >>
Except that the total amount of electricity flowing through the steel plate and the amount of current to the carrier roll 65 (first roll) when the electrolytic treatment is performed on the steel plate are as shown in Table 1, it is the same as in Example 4. A surface-treated steel sheet was obtained and evaluated in the same manner. The results are shown in Table 1.

Example 7
A cold-rolled steel plate (thickness 0.2 mm, width 1000 mm) was prepared as an original plate. The prepared steel sheet was electrolytically degreased, washed with water, and then subjected to cathodic electrolysis using a surface treatment line 100 shown in FIG. The amount of the electrolytic treatment liquid 31 is 8000 L, the capacity of the first electrolytic treatment tank 30 is 2500 L, the line speed (moving speed of the steel plate): 150 m / min, the number of cycles: 2 times, the energization time per cycle: 0.6 A surface-treated steel sheet was obtained in the same manner as in Example 1 except that the conditions were as follows: the total amount of electricity flowing through the steel sheet: 9 C / dm ² , and the current amount to the carrier roll 65 (first roll): 4760 A. Evaluation was performed. The results are shown in Table 1.

Example 8
In Example 8, the surface treatment line 100 formed by replacing the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 in the surface treatment line 100 shown in FIG. 1 with those shown in FIG. A steel plate was produced. The amount of the electrolytic treatment liquids 31 and 41 is 8000 L, the capacity of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 is 2500 L, the line speed (moving speed of the steel plate): 150 m / min, the number of cycles: four times, Energizing time per cycle: 0.6 seconds, total amount of electricity flowing through the steel plate: 19 C / dm ² , carrier rolls 65 and 67a (first roll, second roll) are energized conductor rolls, while carrier rolls 69 (third roll) was a non-conducting roll. Others were obtained in the same manner as in Example 7, and surface-treated steel sheets were obtained and evaluated in the same manner. The results are shown in Table 1.

<< Comparative Example 1 >>
In Comparative Example 1, a cold-rolled steel sheet (thickness 0.2 mm, width 200 mm) similar to that used in Example 1 was electrolytically degreased, washed with water, and surface-treated with the following lines. That is, the surface-treated steel sheet was produced using the surface treatment line 100 obtained by replacing the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 in the surface treatment line 100 shown in FIG. 1 with those shown in FIG. . In the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 shown in FIG. 3, the carrier rolls 65, 67a, and 69a (first to third rolls) are all conductive rolls that are energized. Moreover, also in the comparative example 1, similarly to Example 4 mentioned above, it electrolyzed in the 1st electrolytic treatment tank 30 and the 2nd electrolytic treatment tank 40, circulating the electrolytic treatment liquids 31 and 41, respectively.

In the electrolytic treatment in Comparative Example 1, the steel sheet is conveyed by each carrier roll, and in the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40, the line speed (moving speed of the steel sheet): 20 m / min, the number of cycles: 4 times. Energizing time per cycle: 0.6 seconds, total electricity flowing through the steel plate: 8.6 C / dm ² , current amount to carrier rolls 65, 67a, 69a (first to third rolls): 68A, 27A and 20A were carried out, thereby forming a metal oxygen compound film on the steel sheet.

  And after forming a metal oxygen compound membrane | film | coat on a steel plate by electrolytic treatment, the steel plate was washed with water in the electrolyte rinse treatment tank 50, the surface-treated steel plate was obtained, and it evaluated similarly to Example 1. FIG. The results are shown in Table 1. In Comparative Example 1, the amount of metal oxygen compound deposited on the carrier roll was measured on the roll surface of each of two carrier rolls, ie, carrier roll 67a (second roll) and carrier roll 69a (third roll). The total value of the weight of the product (oxygen compound of Zr) was measured. The results are shown in Table 1.

<< Comparative Examples 2-4 >>
Except that the total amount of electricity flowing through the steel plate and the current amount to the carrier rolls 65, 67a, 69a (first to third rolls) when performing electrolytic treatment on the steel plate are as shown in Table 1. In the same manner as in Comparative Example 1, a surface-treated steel sheet was obtained and evaluated in the same manner. The results are shown in Table 1.

<< Comparative Example 5 >>
A cold-rolled steel sheet (thickness 0.2 mm, width 1000 mm) similar to that used in Example 7 was electrolytically degreased, washed with water, and surface-treated with the following lines. That is, in the surface treatment line 100 shown in FIG. 1, a surface-treated steel sheet was produced using the surface treatment line 100 in which the part shown in FIG. 2 was changed as shown in FIG. The amount of the electrolytic treatment liquids 31 and 41 is 8000 L, the capacity of the first electrolytic treatment tank 30 and the second electrolytic treatment tank 40 is 2500 L, the line speed (moving speed of the steel plate): 150 m / min, the total amount of electricity flowing through the steel plate : 14 C / dm ² , and the carrier rolls 65, 67 a, 69 a (first to third rolls) were energized conductor rolls. Others were obtained in the same manner as in Comparative Example 1, and surface-treated steel sheets were obtained and evaluated in the same manner. The results are shown in Table 1.

なお、表１中、電気抵抗値の「＞２０」は、電気抵抗値が２０Ωより大きい値となったことを示す。

In Table 1, the electrical resistance value “> 20” indicates that the electrical resistance value is greater than 20Ω.

  As shown in Table 1, in Examples 1 to 3 and 7, the carrier roll 65 (first roll) is a conductive roll, while the carrier roll 67 (second roll) is a non-conductive roll. However, no arc spot is confirmed on the surface of the surface-treated steel sheet, and the adhesion of oxygen compounds to the carrier roll during the production of the surface-treated steel sheet is effectively prevented, and the surface-treated steel sheet can be produced satisfactorily. It was. Similarly, as shown in Table 1, in Examples 4 to 6, while the carrier roll 65 (first roll) is a conductive roll, the carrier rolls 67 and 69 (second roll and third roll) are used. Both are non-conducting rolls, and no arc spot is confirmed on the surface of the surface-treated steel sheet. Further, adhesion of oxygen compounds to the carrier roll during the production of the surface-treated steel sheet is effectively prevented. The steel plate could be manufactured satisfactorily.

  In the eighth embodiment, the carrier rolls 65 and 67a (first roll and second roll) are made conductive conductors, while the carrier roll 69 (third roll) is made a non-conductive roll, and the first roll and second roll. By adjusting the amount of current flowing through the roll, no arc spot is confirmed on the surface of the surface-treated steel sheet, and the adhesion of oxygen compounds to the carrier roll during the production of the surface-treated steel sheet is effectively prevented, The surface-treated steel sheet was successfully manufactured.

  On the other hand, as shown in Table 1, in Comparative Examples 1 to 5, all the carrier rolls (the first roll to the third roll) are conductor rolls that are energized, and arc spots are generated on the surface-treated steel sheets. Furthermore, when producing the surface-treated steel sheet, the oxygen compound adhered to the carrier roll, and the surface-treated steel sheet could not be produced satisfactorily.

  Next, in Examples 9 to 11 and Comparative Examples 6 to 9 to be described later, experimental examples are shown in which metal cans were produced, the contents were filled into the produced metal cans, and the content resistance (corrosion resistance) was evaluated.

Example 9
1. Production of surface-treated steel sheet A surface-treated steel sheet was produced in the same manner as in Example 4 except that a cold-rolled steel sheet having a thickness of 0.225 mm and a tempering degree T3 was used as the steel sheet. In the same manner as in Example 1, the presence / absence of an arc spot was evaluated. The results are shown in Table 2.

2. Preparation of resin-coated surface-treated steel sheet The obtained surface-treated steel sheet was previously heated to a plate temperature of 250 ° C., and polyethylene terephthalate containing 11 mol% of isophthalic acid component on one side of the metal plate on the inner surface side of the can / Copolymer stretched film (thickness 19 μm) of isophthalate, polyethylene terephthalate / isophthalate copolymer stretched white film (thickness 13 μm) containing 12 mol% of isophthalic acid component on the other side of the outer surface of the can The resin-coated surface-treated steel sheet was obtained by water-cooling immediately after thermocompression bonding via a laminate roll.

3. Production of metal cans After both sides of the obtained resin-coated surface-treated steel sheet were electrostatically oiled with paraffin wax, they were punched into a circle with a diameter of 143 mm, and a drawn cup with a diameter of 91 mm and a height of 36 mm was produced according to a conventional method. The squeezed cup was subjected to molding of a metal can (200 g seamless can) described later. Subsequently, the drawing cup was simultaneously drawn and ironed twice to form a cup having a small diameter and a large height. Various characteristics of the cup thus obtained were as follows.
Cup diameter 52.0mm
Cup height 111.7mm
The thickness of the can wall relative to the original plate thickness -30%
This cup is heat-treated at 220 ° C. for 60 seconds after doming molding, followed by trimming of the end of the opening, curved printing, neck-in processing and flange processing to a diameter of 50.8 mm A metal can (a seamless can for 200 g) was produced.

4). Filling evaluation (pack test (dent resistance))
The obtained metal can was filled with 185 ml of coffee (trade name Blendy bottle coffee low sugar, manufactured by Ajinomoto General Foods Co., Ltd.), and the lid was wound according to a conventional method, followed by a retort treatment at 123 ° C. for 20 minutes. Store at room temperature for 1 day with the lid on top, and then leave it sideways, and place a 1 kg weight with a spherical surface with a diameter of 52.0 mm on the bottom of the side wall of the can body from a height of 40 mm. The can body was impacted and deformed by dropping it so as to hit the can. After storing for 3 months at 37 ° C with the lid facing upward, cut the winding part with a can opener, remove the lid from the can body, and observe the corroded state of the inner surface of the can body with a microscope. evaluated. As the evaluation criteria, 50 cans were examined, and no corrosion due to blisters occurred in any can. On the other hand, if 50 cans were examined and corrosion caused by blisters occurred in one can or in a can, it was marked as x. The evaluation results are shown in Table 2.

<< Examples 10 and 11 >>
A surface-treated steel sheet was produced in the same manner as in Examples 5 and 6, except that a cold-rolled steel sheet having a thickness of 0.225 mm and a tempering degree T3 was used as the steel sheet. The surface-treated steel sheet produced by the method of Example 5 corresponds to Example 10, and the surface-treated steel sheet produced by the method of Example 6 corresponds to Example 11. Next, the obtained surface-treated steel sheet was evaluated for the presence or absence of an arc spot in the same manner as in Example 1. Thereafter, in the same manner as in Example 9, a metal can was prepared and the filling of the contents was evaluated. The results are shown in Table 2.

<< Comparative Examples 6-9 >>
A surface-treated steel sheet was produced by the same method as Comparative Examples 1 to 4, except that a cold-rolled steel sheet having a thickness of 0.225 mm and a tempering degree T3 was used as the steel sheet. The surface-treated steel sheet produced by the method of Comparative Example 1 is in Comparative Example 6, the surface-treated steel sheet produced by the method of Comparative Example 2 is in Comparative Example 7, and the surface-treated steel sheet produced by the method of Comparative Example 3 is Comparative Example. 8, the surface-treated steel sheet produced by the method of Comparative Example 4 corresponds to Comparative Example 9, respectively. Next, the obtained surface-treated steel sheet was evaluated for the presence or absence of an arc spot in the same manner as in Example 1. The results are shown in Table 2. In addition, the surface-treated steel sheets produced in Comparative Examples 6 to 9 are inferior in content resistance (corrosion resistance) without confirming the presence of arc spots as shown in Table 2 and without performing the above-described content filling evaluation. Since it was possible to determine that there was a metal can, the evaluation of filling and contents filling was not performed.

  As shown in Table 2, in Examples 9 to 11, while the carrier roll 65 (first roll) is a conductive roll, the carrier rolls 67 and 69 (second roll and third roll) are non-conductive rolls. In any case, no arc spot was confirmed on the surface of the surface-treated steel sheet, and the surface-treated steel sheet could be manufactured satisfactorily. Furthermore, metal cans made by processing these surface-treated steel sheets are filled with contents, then subjected to retort treatment, subjected to can deformation by external force, and even when stored over time, It was excellent in (corrosion resistance).

  On the other hand, as shown in Table 2, in Comparative Examples 6 to 9, all the carrier rolls (the first roll to the third roll) are made conductive conductors, and all of them generate an arc spot on the surface-treated steel sheet. As a result, the surface-treated steel sheet could not be produced satisfactorily.

DESCRIPTION OF SYMBOLS 1 ... Base material 100 ... Surface treatment line 10 ... Pickling tank 20 ... Pickling rinse process tank 30 ... 1st electrolytic treatment tank 31 ... Electrolytic treatment liquid 40 ... 2nd electrolytic treatment tank 41 ... Electrolytic treatment liquid 50 ... Electrolysis Liquid rinsing tank 61, 63, 65, 67, 67a, 69, 69a, 71 ... Carrier roll 62, 64, 66, 68, 70 ... Sink roll 80a, 80b, 80c, 80d, 80e, 80f, 80g, 80h ... Anode 90 ... Rectifier

Claims (10)

Using an electrolytic treatment line having a plurality of electrolytic treatment tanks containing metal ions and treatment electrodes and electrodes, a steel plate is continuously fed into each electrolytic treatment bath, and in each electrolytic treatment bath, the steel plate and A method for producing a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet by performing electrolytic treatment by flowing a direct current between the electrodes,
The steel plate is provided for each of a plurality of the electrolytic treatment tanks, a roll for feeding the steel plate into the electrolytic treatment tank, and a roll for lifting the steel plate from the electrolytic treatment tank, Sent continuously into each electrolytic treatment tank constituting the treatment line,
The plurality of rolls provided in the electrolytic treatment line are energized rolls electrically connected to a power source for passing a direct current through the steel sheet, and non-energized rolls not connected to the power source,
After the metal oxygen compound is formed by electrolytic treatment on the surface of the steel sheet in contact with the roll, an arc spot is generated by arranging the energizing roll so that the metal oxygen compound and the energizing roll do not contact each other. A method for producing a surface-treated steel sheet, characterized in that it is not allowed to occur.   Of the plurality of rolls provided in the electrolytic treatment line, a power source for supplying a direct current to the steel plate is a roll for sending into the electrolytic treatment tank that first performs electrolytic treatment on the surface of the steel plate that contacts the roll. The method for producing a surface-treated steel sheet according to claim 1, wherein the surface-treated steel sheet is electrically connected to the energizing roll. Using an electrolytic treatment line having a plurality of electrolytic treatment tanks containing metal ions and treatment electrodes and electrodes, a steel plate is continuously fed into each electrolytic treatment bath, and in each electrolytic treatment bath, the steel plate and A method for producing a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet by performing electrolytic treatment by flowing a direct current between the electrodes,
The steel plate is provided for each of a plurality of the electrolytic treatment tanks, a roll for feeding the steel plate into the electrolytic treatment tank, and a roll for lifting the steel plate from the electrolytic treatment tank, Sent continuously into each electrolytic treatment tank constituting the treatment line,
The plurality of rolls provided in the electrolytic treatment line are energized rolls electrically connected to a power source for passing a direct current through the steel sheet, and non-energized rolls not connected to the power source,
By controlling the resistance value of the film containing the metal oxygen compound on the surface in contact with the energizing roll of the steel sheet, the voltage applied to the energizing roll, and the number of energizing rolls to be arranged, the steel plate and A method for producing a surface-treated steel sheet, wherein an arc spot is not generated when the current-carrying roll comes into contact. A steel plate is continuously fed into an electrolytic treatment tank including a treatment liquid containing metal ions and an electrode, and in the electrolytic treatment tank, an electrolytic treatment is performed by flowing a direct current between the steel plate and the electrode. Performing a method for producing a surface-treated steel sheet having a step of forming a film containing a metal oxygen compound on the surface of the steel sheet,
The steel sheet is continuously fed into the electrolytic treatment tank by a first roll for feeding the steel sheet into the electrolytic treatment tank and a second roll for lifting the steel sheet from the electrolytic treatment tank. ,
The first roll is an energizing roll electrically connected to a power source for flowing a direct current through the steel plate,
The method for producing a surface-treated steel sheet, wherein the second roll is a non-conducting roll not connected to a power source.   The method for producing a surface-treated steel sheet according to any one of claims 1 to 4, wherein the treatment liquid contains at least one metal ion of Zr, Al, and Ti.   The pH of the said process liquid is 2-5, The manufacturing method of the surface treatment steel plate in any one of Claims 1-5 characterized by the above-mentioned.   The method for producing a surface-treated steel sheet according to any one of claims 1 to 6, wherein an electric resistance value of the surface of the film formed on the surface of the steel sheet is 0.1Ω or more. The method for producing a surface-treated steel sheet according to any one of claims 1 to 7, wherein the molar amount of the metal in the film formed on the surface of the steel sheet is 0.5 mmol / m ² or more.   The method for producing a surface-treated steel sheet according to any one of claims 1 to 8, wherein the thickness of the film formed on the surface of the steel sheet is 15 nm or more. A surface-treated steel sheet for metal cans, which is produced using the method for producing a surface-treated steel sheet according to any one of claims 1 to 9.

Images