JP2015202517A - surface treatment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treatment method capable of performing more efficiently the surface treatment of steel material.SOLUTION: First, a steel material processing part produces steel material having a predetermined shape and predetermined properties (Step S1). The steel material produced by a steel material processing part has the temperature higher than ambient temperatures, and is conveyed to a surface treatment part before the temperature is cooled to ambient temperatures. When the steel material is conveyed, the surface treatment part performs the surface treatment for the steel material of the temperature higher than ambient temperatures (Step S2).

Description

  The present invention relates to a surface treatment method for a steel material.

  Conventionally, steel materials such as rebars used for reinforced concrete utility poles are prone to hydrogen embrittlement. Therefore, it has been proposed to suppress hydrogen embrittlement by performing surface treatment such as plating or painting (for example, , See Patent Document 1). For example, in Patent Document 1, the state of an additive in a steel material is changed by forming a surface layer made of an oxide that is reduced at a potential nobler than a potential at which hydrogen ions are reduced on the surface of the steel material. However, it has been reported that hydrogen embrittlement in steel materials can be suppressed.

JP2013-124410A

  In the surface treatment as described above, raw materials such as crude steel are shaped by rolling or material adjustment by heat treatment, etc. to form steel materials such as rolls and rods, and then cooled once for storage and transportation. After that, the steel material was transported to a surface treatment apparatus and heated again to a temperature necessary for the surface treatment. Thus, in order to perform the surface treatment of the steel material, energy and time are wasted because the steel material is cooled or reheated.

  Then, an object of this invention is to provide the surface treatment method which can perform the surface treatment of steel materials more efficiently.

  In order to solve the problems as described above, a surface treatment method according to the present invention includes a first step of forming a steel material through a process involving heating, and the steel material heated by the first step to room temperature. And a second step of performing a surface treatment of the steel material without cooling.

  In the surface treatment method, the second step may include a step of setting the temperature of the steel material to a temperature suitable for the surface treatment before performing the surface treatment.

  According to the present invention, a steel material formed through a heating process is subjected to a surface treatment without cooling to room temperature, whereby the steel material is cooled for transportation and storage, or the cooled steel material is subjected to a surface treatment. Therefore, it is possible to perform the surface treatment of the steel material more efficiently.

FIG. 1 is a diagram showing a configuration of a surface treatment system for realizing a surface treatment method according to a first embodiment of the present invention. FIG. 2 is a flowchart showing the surface treatment method according to the first embodiment of the present invention. FIG. 3 is a diagram showing a configuration of a surface treatment system for realizing a surface treatment method according to the second embodiment of the present invention. FIG. 4 is a flowchart showing a surface treatment method according to the second embodiment of the present invention.

[First Embodiment]
As shown in FIG. 1, a surface treatment system for realizing a surface treatment method according to a first embodiment of the present invention is processed by a steel material processing unit 1 that processes a steel material 10 and the steel material processing unit 1. The surface treatment part 2 which performs surface treatment with respect to the steel material 10 is provided.

The steel material processing unit 1 is a device that performs processing for generating a steel material 10 having a predetermined shape and predetermined properties such as a plate material, a bar material, and a wire material. This process includes at least a process involving heating, such as shaping such as rolling and drawing, and material adjustment by heat treatment. Therefore, the temperature of the steel material 10 produced | generated by the steel material process part 1 is higher than normal temperature. Thus, the steel material 10 produced | generated in the steel material process part 1 is conveyed by the surface treatment part 2 without being cooled to normal temperature.
In addition, as long as the steel material 10 which has a temperature higher than normal temperature is produced | generated in the state just before performing a surface treatment, the process by the steel material process part 1 may be made to include various processes. For example, steel production from raw materials, shaping from a steel ingot, and material adjustment by heat treatment may be included.

The surface treatment unit 2 is a device that performs a surface treatment on the steel material 10 generated by the steel material processing unit 1. Usually, the surface treatment with respect to the steel material 10 is performed at the temperature suitable for the surface treatment of the steel material 10 higher than normal temperature. As described above, since the temperature of the steel material 10 conveyed from the steel material processing unit 1 is higher than the normal temperature, the temperature is more suitable for the surface treatment than the normal temperature. Therefore, in the present embodiment, the steel material 10 is already at a temperature suitable for surface treatment higher than room temperature, so that the surface treatment unit 2 is directly applied to the steel material 10 conveyed from the steel material processing unit 1, That is, the surface treatment is performed without performing a heat treatment such as heating or cooling.
As the surface treatment, at least one of electrochemical treatment, gas treatment, and coating treatment is performed.

The electrochemical treatment is a treatment for forming on the surface of the steel material 10 a surface layer made of an oxide that is reduced at a potential nobler than a potential at which hydrogen ions are reduced by plating or oxidation. The surface layer formed on the steel material 10 may form an oxide of a semi-finished component, or may form an oxide other than a semi-finished component by a plating bath.
As the gas treatment, carburizing treatment for adding carbon to metal, nitriding treatment for immersing nitrogen in the metal, oxidation treatment, or the like is performed.
As the coating treatment, solvent-based paint or water-based paint, powder coating, or the like is performed. In this powder coating, powders mainly composed of oxides may be used. However, even if a general organic material other than oxides is used, for example, hydrogen ions are reduced at a potential that is higher than the potential at which hydrogen ions are reduced. It is considered that the same effect as that obtained when an oxide is used can be obtained.

  Next, the surface treatment method according to the present embodiment will be described with reference to FIG.

  First, the steel material processing unit 1 generates a steel material 10 having a predetermined shape and a predetermined property (step S1). The steel material 10 produced | generated by the steel material process part 1 becomes temperature higher than normal temperature, and before this temperature is cooled to normal temperature, it is conveyed by the surface treatment part 2. FIG.

  If the steel material 10 is conveyed, the surface treatment part 2 will perform surface treatment with respect to the steel material 10 used as a temperature higher than normal temperature (step S2). Thereby, the steel material 10 by which the surface treatment was performed will be produced | generated.

Here, when performing an electrochemical process in the surface treatment part 2, the solution which contacts the steel material 10 cools the steel material 10 in order to perform an electrochemical process. For this reason, since it is not necessary to cool in advance the steel material processed into the predetermined shape like the past, it is possible to shorten the time from when the steel material is generated until the surface treatment is started.
In the case of performing gas treatment, conventionally, it has been necessary to heat the cooled steel material to a temperature at which the reaction occurs, but the steel material 10 conveyed from the steel material processing unit 1 already has a temperature higher than room temperature. Therefore, it is not necessary to heat the steel material. Moreover, since the steel material 10 conveyed from the steel material processing part 1 has already become temperature higher than normal temperature, as soon as it reaches the surface treatment part 2, surface treatment can be started. As a result, it is possible to realize energy saving by omitting heating and shortening of manufacturing time by shortening the start time of surface treatment.
Moreover, when performing a coating process, since the steel material 10 becomes temperature higher than normal temperature when apply | coating a solvent-type coating material and a water-based coating material, the applied coating material can be dried in a short time. In the case of applying powder paint, conventionally, it has been necessary to heat a cooled steel material for coating. However, the steel material 10 conveyed from the steel material processing unit 1 is already at a temperature higher than room temperature. Therefore, the steel material 10 does not have to be heated, and the steel material 10 that has been transported can be coated immediately. As a result, it is possible to realize energy saving by omitting heating and shortening of manufacturing time by shortening the start time of the surface treatment.

  As described above, according to the present embodiment, the steel material 10 formed in a predetermined shape is subjected to a surface treatment without cooling it to room temperature, so that the steel material can be transported or stored and cooled. Since the process of heating the steel material for the surface treatment can be omitted, the surface treatment of the steel material can be performed more efficiently.

  Conventionally, a steel ingot is formed into a rod shape by drawing, and after induction-hardening to produce a steel material having a predetermined hardness, it is cooled by water cooling or the like for storage or transportation In order to perform surface treatment such as powder coating or hot dip galvanization, the cooled steel material has been heated. In contrast, in the present embodiment, after a steel material is generated by performing drawing and induction hardening, surface treatment such as powder coating or hot dip galvanization is performed as it is, that is, without cooling to room temperature. Thereby, since it is not necessary to heat steel materials for surface treatment, the energy and time which this heating requires can be saved.

[Second Embodiment]
Next, a second embodiment according to the present invention will be described. In the present embodiment, a heat treatment unit is further provided in the surface treatment system in the first embodiment described above. Therefore, in the present embodiment, the same names and reference numerals are assigned to the same configurations and steps as those in the first embodiment described above, and description thereof is omitted as appropriate.

  As shown in FIG. 3, the surface treatment system for realizing the surface treatment method according to the present embodiment includes a steel material processing unit 1 that processes a steel material 10 having a predetermined shape and predetermined characteristics, and the steel material processing unit. The heat processing part 3 which heat-processes with respect to the steel material processed by 1 and the surface treatment part 2 which performs surface treatment with respect to the steel material 10 heat-processed by this heat processing part 3 are provided.

  The heat treatment unit 3 is a device for heating or cooling the steel material 10 processed by the steel material processing unit 1. The heat treatment unit 3 performs heat treatment on the steel material 10 so that the steel material 10 has a temperature suitable for the surface treatment performed in the surface treatment unit 2.

  Next, a surface treatment method according to the present embodiment will be described with reference to FIG.

  First, the steel material processing part 1 produces | generates the steel material 10 which has a predetermined shape and a predetermined characteristic (step S1). The steel material 10 produced | generated by the steel material process part 1 becomes temperature higher than normal temperature, and before this temperature is cooled to normal temperature, it is conveyed by the heat processing part 3. FIG.

  When the steel material 10 is conveyed, the heat treatment unit 3 performs heat treatment on the steel material 10 so that the steel material 10 has a temperature suitable for the surface treatment (step S3). As described above, the steel material 10 processed by the steel material processing unit 1 has a temperature higher than the normal temperature, and is conveyed to the heat treatment unit 3 before the temperature is cooled to the normal temperature. Then, the heat processing part 3 makes the temperature of the steel material 10 the temperature suitable for surface treatment by heating or cooling with respect to the steel material 10 on the basis of the temperature when it has been conveyed. Thus, in the heat processing part 3, heat processing is performed from the temperature of the state heated by the steel material process part 1, not the temperature of the steel material 10 from normal temperature. Thereby, when heating the steel material 10 in the heat treatment part 3, since heating is performed from a temperature higher than normal temperature, the temperature suitable for surface treatment with a shorter time and less energy than in the case of heating from normal temperature as in the prior art, can do. On the other hand, since only the cooling is performed when the steel material 10 is cooled in the heat treatment section 3, it takes a shorter time and less energy than the conventional case where the temperature is set to room temperature and then heated again to a temperature suitable for the surface treatment. It can be set to a temperature suitable for the surface treatment.

  When the steel material 10 having a temperature suitable for the surface treatment is conveyed, the surface treatment unit 2 performs a surface treatment on the steel material 10 (step S2). Thereby, the steel material 10 by which the surface treatment was performed will be produced | generated.

  As described above, according to the present embodiment, the temperature of the steel material 10 is set to a temperature suitable for the surface treatment in the heat treatment unit 3 before performing the surface treatment in the surface treatment unit 2, thereby reducing the time in a shorter time than in the past. Since it can be set to the temperature suitable for surface treatment with energy, surface treatment of steel materials can be performed more efficiently.

  The present invention can be applied to various treatments in which surface treatment is performed on a heated member.

  DESCRIPTION OF SYMBOLS 1 ... Steel material processing part, 2 ... Surface treatment part, 3 ... Heat processing part, 10 ... Steel material.

Claims (2)

A first step of forming a steel material through a process involving heating;
A surface treatment method comprising: a second step of performing a surface treatment of the steel material without cooling the steel material heated in the first step to room temperature. The surface treatment method according to claim 1,
The second step includes a step of setting the temperature of the steel material to a temperature suitable for the surface treatment before performing the surface treatment.

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