JP2002172409A - Method for preventing and processing burn-in of guide or transfer member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preventing and processing seizing of a guide or a transfer member capable of obtaining a high seizing prevention effect through an inexpensive processing method, and also to provide a hot rolling equipment whose one of guides or transfer members at least used in each equipment or between each equipment in hot rolling equipment is a member protected by the seizing preventing and processing method. SOLUTION: In the processing method to form an oxide film on the surface of the guide or the transfer member in order to prevent seizing of the guide or the transfer member which contacts with the steel strip, a method for preventing and processing seizing of the guide or the transfer member characterized by the feature that an application of dilute hydrochloric acid, or aquafortis or dilute sulphuric acid on the surface of the guide or the transfer member enables the oxide film to be formed on the surface of the guide or the transfer member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a guide or conveying member used in an environment in which seizure is likely to occur, for example, a guide roll such as a pinch roll, a metal product conveying roll, and a seizure other than the roll. The present invention relates to a method for preventing seizure of a guide used in an environment in which cracks easily occur, for example, a sliding surface of a steel plate such as a side guide of a hot rolling facility.

[0002] In the present invention, the guide or transport member refers to a member that is used in contact with these members when guiding the guided member or when transporting the transported member.

[0003]

2. Description of the Related Art It is known that seizure of a roll does not occur if a film is formed on the surface of the roll before the use of the roll and a treatment is taken so as to prevent metal-to-metal contact between the roll surface and the product from an early stage of operation. ing. This phenomenon means that seizure does not occur by preventing metal-to-metal contact that occurs between the roll surface and the product.

Japanese Patent Application Laid-Open No. 58-212284 discloses that from the viewpoint of preventing the seizure of a roll by treating the roll surface with an oxide film, the roll surface is heated to form an oxide film, or the roll surface is treated. A technique of forming an oxide film by heating in a caustic soda solution is disclosed.
In addition, similar effects can be obtained by oxidizing treatment with chromic acid, sulfurizing treatment, phosphoric acid film treatment, etc., and in the case of rolls made of low corrosion resistant material such as low chromium steel, water It is disclosed that the same effect can be expected by forming rust on the surface by immersing in water or applying water before use after assembling the roll.

Japanese Patent Application Laid-Open No. 5-329508 discloses that a powder of carbon steel or low alloy steel, which is more easily oxidized than a material to be rolled and a roll, is supplied to the surface of a steel material before rolling.
A method for rolling steel is disclosed.

[0006] Japanese Patent Application Laid-Open No. 60-86262 discloses that a metal core for a seamless steel pipe is prepared by using steam: 5.0% by volume or more, oxygen:
0.5 to 5.0% by volume, the balance being substantially composed of an inert gas, and the volume ratio of oxygen to steam being less than 1/3 in a mixed gas atmosphere.
It is disclosed that a scale (oxide film) is formed on the surface of the core by heating and maintaining the temperature at 000 ° C. or less to extend the life of the core for a seamless steel pipe.

[0007]

However, the above-mentioned prior art has the following problems.

In the technique disclosed in Japanese Patent Application Laid-Open No. 58-212284, heating is required to form an oxide film on the roll surface, and a separate device for heating the roll surface is required. In addition, in the treatments such as oxidation treatment with chromic acid, sulfuration treatment, and phosphoric acid film treatment, if these films are partially peeled off due to collision with a steel strip, etc., the effect is lost, so it is necessary to repair each time. is there.

According to the technique disclosed in Japanese Patent Application Laid-Open No. 5-329508, in order to prevent surface roughness of the roll surface and to obtain a rolled product having good surface quality in hot rolling of steel, the surface of the material to be rolled and the roll must be fixed. In order to supply the powder of carbon steel or low alloy steel, for example, an air atomizing device is required, which increases the cost.

According to the technique disclosed in Japanese Patent Application Laid-Open No. 60-86262, it is possible to form a dense scale having excellent adhesion, but the scale according to the present method is very thin and prevents seizure of a roll in contact with a steel strip. Effect cannot be obtained for forming an oxide film on the surface of the roll. Further, in a mixed gas atmosphere of steam and oxygen, an electric furnace or the like for heating and holding at a temperature of 1000 ° C. or less is required, and the electric furnace is not suitable for processing large members such as rolls and guides,
Partial treatment of large parts is also difficult.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a method of preventing sticking of a guiding or conveying member which can obtain a high effect of preventing sticking by an inexpensive processing method. It is in. Another object of the present invention is to provide, in a hot rolling facility, at least one of the guide or transport members used in each facility or between the facilities is a member subjected to the above-described anti-seizure treatment method. To provide facilities.

[0012]

The present inventors have studied a method of forming an oxide film which is inexpensive and can provide a high seizure prevention effect. As a result, the surface of a member for guiding or transporting with dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid is examined. The surface of the guide or transport member is treated with an oxide film, particularly dilute hydrochloric acid or dilute nitric acid or dilute sulfuric acid in which iron is dissolved, so that an oxide film is formed on the guide or transport member surface to guide or transport. A method for preventing seizure of members for use was found.

[0013] That is, the method for preventing seizing of a member for guiding or conveying according to the present invention has the following features.

(1) In a treatment method for forming an oxide film on the surface of a guide or transport member in order to prevent seizure of the guide or transport member in contact with the steel strip, the surface of the guide or transport member is diluted with hydrochloric acid. Alternatively, an anti-seizure treatment method for a guide or transport member, wherein an oxide film is formed on the surface of the guide or transport member by applying diluted nitric acid or diluted sulfuric acid.

(2) In a treatment method for forming an oxide film on the surface of the guide or transfer member in order to prevent seizure of the guide or transfer member in contact with the steel strip, the method of forming an oxide film on the surface of the guide or transfer member may include an iron component. A method for preventing seizure of a guide or transport member, wherein an oxide film is formed on the surface of the guide or transport member by applying diluted hydrochloric acid, diluted nitric acid or diluted sulfuric acid in which is dissolved.

(3) A member for guiding or transporting, wherein the anti-seizure treatment described in (1) or (2) above is performed.

(4) The guide or transport member according to (3), wherein the guide or transport member is a pinch roll.

(5) The guide or transport member according to (3), wherein the guide or transport member is a side guide.

(6) The guide or transport member according to (3), wherein the guide or transport member is a transport roll.

(7) In a hot rolling facility having at least a rough rolling facility, a finishing rolling facility, and a hot-rolled steel strip winding facility in this order, a guide used in each facility or between each facility or At least one of the conveying members is a member that has been subjected to the anti-seizure treatment method according to the above (1) or (2).

(8) A step of turning the slab into a rough bar in a rough rolling facility, a step of turning the rough bar into a hot-rolled steel strip in a finishing rolling facility, and a step of pinching and winding the hot-rolled steel strip. In the method for manufacturing a steel strip, the guide or conveying member used in each of the steps or between the steps is subjected to the above (1).
Or a method of manufacturing a steel strip, wherein the member subjected to the method for preventing image sticking according to (2) is used for guiding or transporting the steel strip in each of the steps or between the steps.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have studied a method of forming an oxide film which is inexpensive and which has a high anti-seizure effect. As a result, the principle of the method is not well understood. Guide the surface of the guide or transfer member by oxidizing the surface of the guide or transfer member with sulfuric acid, especially by oxidizing the surface of the guide or transfer member with a dilute hydrochloric acid or dilute nitric acid or diluted sulfuric acid in which iron is dissolved. Alternatively, it was confirmed that an oxide film which was good for the effect of preventing seizure of the transfer member was formed.

Here, the effect was the same regardless of whether dilute hydrochloric acid, dilute nitric acid, or dilute sulfuric acid was used. However, if the concentration exceeds 15%, the surface of the guide or transport member may be melted, so that a concentration of 1 to 15% is preferable.

The method of applying dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid on the surface of the guide or conveying member and the method of applying dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid in which iron is dissolved can be spraying or coating. Usually, a coating method using a brush is adopted. This is because the spraying method is not effective because the solution drips downward. As a guide, the state of formation of an oxide film is good when applied one week before the guide or the transfer member is changed. After the application, it may be dried naturally.

Iron means iron or iron oxide. One form of iron is iron powder (cutting powder), which has a large particle, and is used by filtering the solution once. Another form of iron is a bolt or the like immersed in a solution, which was used without filtration. However, iron oxide was used without filtration because the particles were already fine. Here, iron or iron oxide does not need to be completely dissolved in dilute hydrochloric acid, dilute nitric acid, or dilute sulfuric acid solution, and may be used without being dissolved. Undissolved makes it easier to apply with a brush. However, it is considered that only the dissolved iron content actually has significance in forming an oxide film on the surface of the guide or transport member.

There was no difference in the effect between iron and iron oxide. However, dilute hydrochloric acid, dilute nitric acid, or dilute sulfuric acid solution in which iron of iron or iron oxide was dissolved was diluted with dilute hydrochloric acid, dilute nitric acid, or dilute nitric acid containing no iron. It was confirmed that an oxide film which was harder than a dilute sulfuric acid solution and did not peel off immediately could be formed.

The present invention is not limited to a guide or transport member used in an environment where seizure is likely to occur, such as a guide roll such as a pinch roll or a vertical roll in a side guide, a metal product transport roll, and a roll other than the roll. It is also useful for a guide used in an environment where seizure easily occurs, for example, a sliding surface of a steel plate such as a side guide of a hot rolling facility.

FIG. 2 shows a hot rolling facility having a rough rolling facility, a finishing rolling facility, and a hot rolled steel strip winding facility in this order. An example of a member is shown. By making the guide or transport member a member to which the above-described seizure prevention processing method is applied, it is possible to prevent the guide or transport member from burning.

Further, a part of the oxide film may be peeled off due to a collision with the steel strip during use. However, in such an environment, the surface of the guide or transfer member is self-oxidized by heat and atmosphere. Since the oxide film is automatically repaired, there is no need for repair.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a general method of manufacturing a hot-rolled steel strip, a hot-rolled steel strip after finish rolling is sprayed with a cooling fluid while being conveyed on a hot run table to a predetermined temperature. And finally wound up on a coiler via a pinch roll as a guide roll.

FIG. 1 shows that, according to the method of the present invention, dilute hydrochloric acid in which dilute hydrochloric acid and iron oxide are dissolved is applied to a pinch roll interposed when a hot-rolled steel strip after finish rolling is wound by a coiler, and hot rolling is performed. The result of the seizure occurrence rate at the time is shown. The seizure occurrence rate is the quality accuracy in the next process or the number of seizures that have occurred in a coiler inspection. The occurrence of seizure was determined by the occurrence of seizure scratches on the inner or outer surface of the steel strip.

Here, dilute hydrochloric acid having a concentration of 10% was used and applied to the rolls three times using a brush 1.5 weeks before the roll change. The dilute hydrochloric acid in which iron oxide was dissolved was a solution in which iron oxide was dissolved in dilute hydrochloric acid having a concentration of 10%, and was applied twice to the roll using a brush 0.8 weeks before changing the roll.

When there is no coating agent, the seizure incidence of the pinch roll is 80%, and when seawater or saline is applied, the seizure incidence is 75%. On the other hand, when dilute hydrochloric acid having a concentration of 10% according to the present invention is applied, the seizure occurrence rate is drastically reduced to 25%, but when dilute hydrochloric acid in which iron oxide is dissolved is applied, the seizure occurrence rate is 5%. The seizure of the roll can be almost completely prevented. The reason why the effect obtained when dilute hydrochloric acid in which iron oxide is dissolved is applied is larger is considered to be that the amount of iron oxide increases by the amount of dissolved iron and the oxide film becomes thicker. In addition, although dilute nitric acid and dilute sulfuric acid were applied instead of dilute hydrochloric acid, the occurrence of seizure did not differ significantly. The seizure occurrence rate was the same even when iron powder was used instead of iron oxide.

The time required to form an oxide film that can withstand seizure is 2 to 2.5 weeks after applying seawater or saline to a pinch roll every 2 days. When dilute hydrochloric acid or dilute nitric acid or dilute sulfuric acid is applied to the pinch roll, the dilute hydrochloric acid or dilute nitric acid or dilute sulfuric acid in which the iron oxide or iron is dissolved is applied to the pinch roll by applying three times for 1 to 1.5 weeks. When used, two coats required 0.3-0.8 weeks.

[0035]

As described above, according to the present invention, the guide or conveying member surface is coated with dilute hydrochloric acid, dilute nitric acid, or dilute sulfuric acid, especially dilute hydrochloric acid, dilute nitric acid, or dilute sulfuric acid in which iron is dissolved. Alternatively, an oxide film which is inexpensive and has a high seizure prevention effect is formed on the surface of the conveying member. By using the guide or transfer member subjected to such a seizure prevention treatment in a hot rolling facility, it is possible to prevent seizure of the guide or transfer member beforehand, thereby improving the yield and improving the surface properties. Excellent steel strip can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing the occurrence rate of seizure of a pinch roll by a roll coating agent.

FIG. 2 is a diagram showing an example of a guiding or conveying member used in or between hot rolling facilities.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shigeru Okada 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Tatsuhiko Yamaoka 1-1-2 Marunouchi, Chiyoda-ku, Tokyo Date (72) Inventor Teruaki Watanabe 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan In-tube (72) Inventor Yuji Torioka 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Japan Inside Steel Pipe Co., Ltd.

Claims (8)

[Claims] In a processing method for forming an oxide film on a surface of a guide or transport member to prevent seizure of a guide or transport member in contact with a steel strip, dilute hydrochloric acid or A method for preventing seizure of a guide or transport member, wherein an oxide film is formed on the surface of the guide or transport member by applying diluted nitric acid or dilute sulfuric acid. 2. A processing method for forming an oxide film on a surface of a guide or transport member to prevent seizure of the guide or transport member in contact with a steel strip, wherein iron is formed on the surface of the guide or transport member. A method for preventing sticking of a guide or transport member, wherein an oxide film is formed on the surface of the guide or transport member by applying dissolved dilute hydrochloric acid, dilute nitric acid or dilute sulfuric acid. 3. A guide or transport member, which has been subjected to the image sticking prevention process according to claim 1 or 2. 4. The guiding or conveying member according to claim 3, wherein the guiding or conveying member is a pinch roll. 5. The guide or transport member according to claim 3, wherein the guide or transport member is a side guide. 6. The guide or transport member according to claim 3, wherein the guide or transport member is a transport roll. 7. A hot rolling facility having at least a rough rolling facility, a finishing rolling facility, and a hot rolled steel strip winding facility in this order, and a guide or transport used in each facility or between the facilities. At least one of the members for
A hot rolling facility, which is a member that has been subjected to the seizure prevention method according to claim 1. 8. A step of forming the slab into a rough bar in a rough rolling facility, a step of forming the rough bar into a hot-rolled steel strip in a finishing rolling facility,
3. A method for manufacturing a steel strip comprising the steps of pinching and winding the hot-rolled steel strip, wherein the guide or transport member used in each of the steps or between the steps is provided with the firing method according to claim 1 or 2. Using a member that has been treated to prevent sticking,
A method for producing a steel strip, wherein the method is used for guiding or conveying a steel strip in each of the steps or between the steps.