JP6021176B2 - Electrogalvanizing method and electrogalvanizing apparatus - Google Patents

Description

  The present invention relates to an electrogalvanizing treatment method and an electrogalvanizing treatment apparatus, and more specifically, it eliminates the possibility of hydrogen embrittlement (delayed fracture) due to electrogalvanizing treatment and reduces cost performance and environmental impact. The present invention relates to a safe electrogalvanizing method and an electrogalvanizing apparatus.

  Steel, high strength steel and ultra high strength steel, which are stronger, are used in various fields such as aircraft parts and aircraft electronic parts, and in recent years they have become lighter and smaller. Therefore, it is also used for automobile parts.

  The steel material is usually subjected to a plating process in order to maintain corrosion resistance and decorativeness. The plating process includes a process of generating hydrogen atoms on the surface of the steel material, such as pickling and electroplating. . Therefore, the generated hydrogen atoms are diffused and absorbed from the surface of the steel material.

  Here, one hydrogen atom that has penetrated into the steel material can normally enter one per iron-centered cubic lattice (crystal lattice), and can move and diffuse freely. However, it is said that two hydrogen atoms cannot penetrate into the iron body-centered cubic lattice at a time. For this reason, it is said that hydrogen atoms that have entered the steel material always exist in the steel material in an atomic state.

  However, the hydrogen atoms that have once entered the steel material have a property of moving to a location where tensile, bending, or compressive stress is concentrated in the steel material, for example, stress such as lattice defects (fine scratches) in the steel material. When a concentrated location occurs, hydrogen atoms concentrate at that location and combine with each other to form hydrogen molecules.

  Here, since the volume of one hydrogen molecule is about three times as large as the volume of two hydrogen atoms, if one hydrogen molecule is formed by two hydrogen atoms, the hydrogen molecule However, excessive stress is applied to the stress concentration portion, thereby destroying the structure of the steel (iron), generating cracks, and expanding and leading to destruction. Such a phenomenon is also referred to as brittle fracture, hydrogen embrittlement, hydrogen embrittlement, and delayed fracture.

  Although the hydrogen embrittlement described above is generally not observed in the steel material immediately after the plating treatment, but occurs with the passage of time, for companies that provide the steel material subjected to the plating treatment, There is a problem that it is impossible to predict whether hydrogen embrittlement will occur.

  In addition, the hydrogen embrittlement tends to occur particularly in high-tensile steels such as carbon tool steels with a high carbon content and carbon steels for machine structures. For steel materials used in the aviation and automobile fields, In order to ensure the surface and quality, it is essential to prevent the hydrogen embrittlement.

  Therefore, in order to prevent the hydrogen embrittlement, conventionally, the steel material after the electroplating treatment, for example, the electrogalvanization treatment is subjected to baking treatment (heating treatment) for a long time at a high temperature, A method of releasing the invading hydrogen atoms to the outside has been adopted.

  Specifically describing a typical electrogalvanizing treatment method of the prior art, as shown in FIG. 7, first, an alkaline degreasing treatment is performed on a steel material to be plated (FIG. 7: S201), After degreasing the surface, it is washed with water and subjected to pickling treatment for surface conditioning (FIG. 7: S202). Next, the adjusted steel material is electrolytically plated to form a zinc plating layer on the surface of the steel material (FIG. 7: S203).

  Here, as described above, since hydrogen atoms are generated by the pickling treatment and the electrolytic plating treatment, in order to remove hydrogen atoms from the steel material, the steel material after the electrolytic plating is subjected to 190 degrees to 210 degrees. Within the range of degrees, the baking process is performed within a range of 3 to 4 hours (FIG. 7: S204). Thereby, the predetermined plating process is completed once.

  Normally, the steel material after the baking treatment is further subjected to a chromate treatment as a secondary processing (FIG. 7: S205), dried with a predetermined dryer (FIG. 7: S206), and inspected ( FIG. 7: S207), the steel material as the final product will be shipped.

  However, the baking treatment has a problem that although hydrogen atoms in the steel material can be removed to some extent, it cannot be completely removed. This problem leads to the possibility of later triggering hydrogen embrittlement of the steel material, and becomes a secondary problem that it does not function as a reliable method for preventing hydrogen embrittlement in terms of safety and quality. In addition, since the time required for the baking treatment is set to a certain length of time, the zinc of the plated layer applied to the steel material is oxidized by the long baking treatment, and the corrosion resistance and the decorative properties are deteriorated. There is.

  In order to solve the above-described problem, for example, Japanese Patent Laid-Open No. 2003-239100 (Patent Document 1) discloses that PR electrolysis (forward / reverse alternating current electrolysis) is performed as an electrolysis treatment in a plating process such as tensile strength steel. The used hydrogen embrittlement prevention plating method is disclosed. As the pretreatment electrolytic treatment, for example, if the + -switching time in PR electrolysis is within 1 minute at 50 degrees to 60 degrees, hydrogen embrittlement does not occur. As a result of being able to perform processing, it is said that stable and good plating can be performed.

  JP-A-5-33806 (Patent Document 2) and JP-A-5-126122 (Patent Document 3) describe a base material made of high-tensile steel and an electric AI formed on the surface of the base material. There is disclosed a fastener excellent in durability and delayed fracture resistance, characterized by comprising a plating layer. The electric AI plating layer is formed by electroplating using a non-aqueous plating solution. As a result, the electric AI plating layer acts as a barrier for hydrogen intrusion to the steel substrate, suppresses hydrogen embrittlement that causes delayed fracture, and also prevents the steel material from absorbing hydrogen during plating layer formation. .

Japanese Patent Application Laid-Open No. 7-54194 (Patent Document 4) discloses that at least one surface of a steel plate having a tensile strength of 100 kgf / mm ² or more is subjected to Ni or Ni-based alloy plating of 50 to 3000 mg / m ² , and A high-tensile cold-rolled steel sheet excellent in delayed fracture resistance, characterized in that Zn or Zn-based alloy plating is applied to the upper layer of 1 to 50 g / m ² is disclosed. The Ni or Ni-base alloy plating and the Zn or Zn-base alloy plating employ a plating method such as an electroplating method or an electroless plating method. Thereby, a Zn or Zn-based alloy-plated high-strength steel plate excellent in delayed fracture resistance can be stably obtained, and its industrial value is said to be extremely large.

  Japanese Patent Laid-Open No. 9-228099 (Patent Document 5) discloses a method for reducing the hydrogen embrittlement caused by the high-strength steel plating process. A plating method for high-strength steel, characterized by performing the treatment, is disclosed. Thereby, since the alkaline anodic electrolytic treatment is performed at the end of the pre-plating process, hydrogen attached to the surface of the material can be removed to reduce the hydrogen embrittlement rate of the high-strength steel.

  JP 2000-282296 A (Patent Document 6) discloses a steel sheet for coating having excellent hydrogen embrittlement resistance and corrosion resistance, characterized by having a steel material and an anodized film formed on the surface of the steel material. Has been. As a result, an anodic oxide film is formed on the surface of the steel material, and hydrogen can be prevented from entering the steel material, so that deterioration of the mechanical properties of the steel material due to hydrogen occlusion can be prevented and excellent. It is said that corrosion resistance can be obtained.

  On the other hand, although not directly related to the hydrogen embrittlement described above, Japanese Patent Laid-Open No. 7-48681 (Patent Document 7) is plated with workpieces having various shapes such as a plate shape, a cylindrical shape, and a corrugated shape. In this case, after pre-processing to adjust the surface condition of the workpiece material, the metal ions in the aqueous metal salt solution are uniformly deposited on the entire surface of the workpiece material by a substitution reaction without using electrical energy. Combined with electroless plating and electroplating, characterized by applying electroless plating to form a metal film, then activating as necessary, then applying normal electroplating, and then final finishing A plating method is disclosed. As a result, the entire surface of a workpiece with a special shape such as a cylindrical shape or a wave shape having a bent portion is glossy like a normal flat plate material, has a beautiful appearance, has excellent corrosion resistance, and has good adhesion. It is said that a uniform metal film can be formed.

JP 2003-239100 A Japanese Patent Laid-Open No. 5-33806 Japanese Patent Laid-Open No. 5-126122 JP-A-7-54194 Japanese Patent Laid-Open No. 9-228099 JP 2000-282296 A JP 7-48681 A

  However, in the invention described in Patent Documents 1-7 described above, a process of generating hydrogen atoms on the surface of the steel material is included in the plating process, so there is room for hydrogen atoms to enter the steel material. There remains a problem that it is unclear whether the plating process method reliably prevents hydrogen embrittlement in terms of safety and quality.

  Moreover, in the prior art, although the plating process includes a baking process, the baking process is costly on the equipment and the like, and a large amount of heat is generated by burning a fuel gas such as propane gas. Therefore, there is a problem that a large amount of carbon dioxide is released, and an environmental load is applied.

  Furthermore, there is a problem that even if the baking process described above is performed, the brittleness cannot be completely removed and delayed fracture occurs.

  Therefore, the present invention has been made to solve the above-mentioned problem, and while reducing the possibility of occurrence of hydrogen embrittlement (delayed fracture) due to electrogalvanizing treatment, cost performance, environmental load reduction, An object of the present invention is to provide a safe electrogalvanizing method and electrogalvanizing apparatus.

  As a result of intensive research, the present inventor has completed a novel electrogalvanizing method and electrogalvanizing apparatus according to the present invention.

  The electrogalvanizing treatment method according to the present invention is an electrogalvanizing treatment method for plating a steel material, and adopts the following configuration.

That is, the electrogalvanizing method according to the present invention includes a first step of roughening the surface of the steel material by blasting, and nickel for preventing hydrogen atoms from entering the upper surface of the rough surface of the steel material. Alternatively, the second step of forming the nickel alloy plating layer by electroless plating and the steel material on which the nickel or nickel alloy plating layer is formed are immersed in an electrolytic plating bath filled with an aqueous zinc metal salt solution. Te, the steel as the cathode, by performing electrolytic plating the bath as the anode, the upper surface of the plating layer of the nickel or nickel alloy, and a third step of forming a plating layer of the zinc electroplating It is characterized by that.

  The third step may be configured not to perform a baking process after the electrolytic plating is completed.

  The thickness of the nickel or nickel alloy plating layer may be 3 μm or more.

  The present invention can also be provided as an electrogalvanizing apparatus for plating steel materials.

That is, the electrogalvanizing apparatus according to the present invention includes a blasting unit that blasts the surface of the steel material to roughen the surface, and nickel that prevents hydrogen atoms from entering the upper surface of the roughened surface of the steel material. An electroless plating treatment part for forming a nickel alloy plating layer by electroless plating and a steel material on which the nickel or nickel alloy plating layer is formed are immersed in an electrolytic plating bath filled with a zinc metal salt aqueous solution. Te, the steel as the cathode, by performing electrolytic plating the bath as the anode, the upper surface of the plating layer of the nickel or nickel alloy, and an electrolytic plating unit for forming a plated layer of the zinc electroplating It is characterized by that. The blast processing unit, the electroless plating processing unit, and the electrolytic plating processing unit are a series of processing apparatuses.

  Moreover, this invention is the steel materials manufactured with the said electrogalvanization processing method or the electrogalvanization processing apparatus.

  According to the electrogalvanization processing method and the electrogalvanization processing apparatus according to the present invention, the occurrence of hydrogen embrittlement (delayed fracture) resulting from electrogalvanization is zero, cost performance, environmental impact reduction, Since it is excellent in safety, it is possible to comprehensively solve safety, quality, cost, and environmental problems.

It is a figure which shows an example of the procedure of the electrogalvanization processing method which concerns on this invention. It is a figure which shows an example of a structure of the electrogalvanization processing apparatus which concerns on this invention. It is a figure which shows an example of the blasting process part of the electrogalvanization processing apparatus which concerns on this invention. It is a figure which shows an example of the electroless-plating process part of the electrogalvanization processing apparatus which concerns on this invention. It is a figure which shows an example of the electroplating process part of the electrogalvanization processing apparatus which concerns on this invention. It is a figure which shows an example of the result of the hydrogen embrittlement degree in an Example, a reference example, and a comparative example. It is a figure which shows an example of the procedure of the electrogalvanization processing method which concerns on a prior art.

  Embodiments of an electrogalvanizing method and an electrogalvanizing apparatus according to the present invention will be described below with reference to the accompanying drawings so that the present invention can be understood. In addition, the following embodiment is an example which actualized this invention, Comprising: The thing of the character which limits the technical scope of this invention is not.

<Electrogalvanizing method>
The electrogalvanizing method according to the present invention is an electrogalvanizing method for plating a steel material. As shown in FIG. 1, first, the surface of the steel material is first blasted to be roughened. (FIG. 1: S101). Next, a second step (FIG. 1: S102) of forming a plating layer of nickel or a nickel alloy for preventing intrusion of hydrogen atoms on the rough surface of the steel material by electroless plating is provided. Finally, a third step (FIG. 1: S103) of forming a zinc plating layer on the upper surface of the nickel or nickel alloy plating layer by electrolytic plating is provided. The electrogalvanizing method according to the present invention basically includes the above-described three steps, and the main plating process is the three steps.

  Thus, by changing the pickling treatment, which has been conventionally performed by roughening the surface of the steel material, to blasting, the possibility of hydrogen atoms generated by the pickling treatment entering the inside of the steel material is zero. To do. Furthermore, a nickel or nickel alloy plating layer for preventing the entry of the hydrogen atoms by electroless plating is formed on the surface of the steel material.

  Here, in the electroless plating process, hydrogen atoms are generated. However, the hydrogen atoms generated in the electroless plating process are different from the hydrogen atoms generated in the electroplating process. Combined with atoms and converted to water). Therefore, in the process of forming the nickel or nickel alloy plating layer, the possibility of hydrogen atoms entering the surface of the steel material is further reduced to zero.

For example, in the electroless plating treatment, when the aqueous electrolyte solution containing metal ions is an aqueous solution in which nickel sulfate (NiSO ₄ ) and hypophosphorous acid (H ₂ PO ₃ ) are dissolved, Hypophosphorous acid (H ₂ PO ₃ ) is decomposed, phosphorus (P) adheres to the nickel (Ni) film, and the remaining two hydrogen atoms (H) combine with one oxygen atom (O). Instantly converted to water (H ₂ O). The remaining two oxygen atoms (O) are bonded to each other and instantly converted into oxygen molecules (O ₂ ). In this way, in the electroless plating treatment, there is no room for hydrogen atoms (H) to enter the surface of the steel material. Therefore, using such a process, nickel or hydrogen that prevents intrusion of hydrogen atoms (H) or A nickel alloy plating layer is formed on the surface of the steel material to eliminate the possibility of hydrogen atoms entering the surface of the steel material.

  Then, if the nickel or nickel alloy plating layer is formed on the surface of the steel material, the nickel or nickel alloy plating layer does not contain the hydrogen even if the subsequent electroplating process for generating hydrogen atoms is performed. The penetration of atoms into the steel material is obstructed, and the possibility of hydrogen atoms entering the steel material is completely zero.

  Therefore, even if a zinc plating layer is formed by electrolytic plating on the surface of the nickel or nickel alloy plating layer, hydrogen atoms do not enter the steel material, so that hydrogen embrittlement of the steel material may occur. Can be set to zero as much as possible. As a result, even if the steel material is used for a long period of time, it is not necessary to worry about the occurrence of hydrogen embrittlement that decreases in strength, so it is possible to provide a steel material that is extremely excellent in safety and quality. .

  Further, in the electrogalvanizing method according to the present invention, it is not necessary to perform a baking process for removing (displacing) hydrogen atoms, which has been conventionally performed, and the baking process itself can be omitted. For this reason, it is possible to reduce the cost and processing time required for the baking process, and it is also possible to reduce the discharge of carbon dioxide associated with the baking process. As a result, it is possible to solve cost and environmental problems.

  Here, in the first step, the blasting process is not particularly limited as long as it is a blasting process that physically roughens the surface of the steel material, but as the blasting process, for example, a shot blasting process, Sand blasting is an example. Of the blasting processes, the shot blasting process is preferable from the viewpoint of workability. The blasting means that a metal such as sand or iron is blown to an object (steel material) at high speed using compressed air or the power of a motor to roughen the object.

  The blasting material used in the blasting can be made of various materials such as an alumina abrasive, a silicon carbide abrasive, and glass beads. The shape of the blast material may be spherical or acute-angled, and the particle size can be appropriately changed in design according to the type and size of the steel material.

  Further, the second step is not particularly limited as long as it is a step of forming a nickel or nickel alloy plating layer for preventing intrusion of hydrogen atoms on the upper surface of the rough surface of the steel material by electroless plating. Examples of the second step include a step of immersing the roughened steel material in an electroless plating bath filled with the metal salt aqueous solution of nickel or nickel alloy. A known technique may be applied to the electroless plating process in the second step. The metal salt aqueous solution means an aqueous electrolyte solution containing metal ions (metal cations). The same applies to the third step.

  Alternatively, the nickel or nickel alloy (for example, a nickel alloy containing phosphorus) may be replaced with a non-ferrous metal having a property of preventing intrusion of hydrogen atoms when a plating layer is formed. Examples of the metal include one, two or more types of non-ferrous selected from the group of aluminum, copper, gold, silver, palladium, lead, chromium, cadmium, and bismuth, or a non-ferrous alloy containing two or more types. It is done. In addition, it is preferable to employ a nickel alloy containing phosphorus from the viewpoint of ease of processing and low cost.

  Here, when the electroless plating is performed with the nickel or the nickel alloy, the aqueous metal salt solution in the electroless plating is, for example, an aqueous solution in which nickel sulfate and hypophosphorous acid of a known reducing agent are dissolved in water. Moreover, when electroless-plating with copper or its alloy, the metal salt aqueous solution in the said electroless plating employ | adopts the aqueous solution which melt | dissolved the copper sulfate and the well-known reducing agent in water, for example.

  The concentration of the metal salt in the nickel or nickel alloy metal salt aqueous solution can be appropriately changed according to the type of the nickel or nickel alloy, the temperature of the bath, and the immersion time. It is preferably within the range of 5% by weight to 5% by weight, and the hypophosphite is preferably within the range of 0.5% by weight to 10% by weight.

  Further, the thickness of the nickel or nickel alloy plating layer is not particularly limited as long as it has a function of preventing the penetration of hydrogen atoms, but as the thickness, for example, the prevention of the penetration of hydrogen atoms. From the viewpoint, 3 μm or more is preferable, and from the viewpoint of cost performance, the range of 3 μm to 5 μm is preferable. With such a configuration, the time and cost required for the electroless plating process can be reduced.

  In addition, the temperature of the electroless plating bath is appropriately changed according to the type of nickel or nickel alloy or the type of metal salt aqueous solution, but in the case of electroless plating of the nickel or nickel alloy, From the viewpoint of time and cost performance, a range of 80 to 85 degrees is preferable. The immersion time (treatment time) of the electroless plating is suitably changed according to the thickness of the nickel or nickel alloy plating layer, but is preferably 10 minutes or more.

  The relationship between the temperature of the electroless plating bath and the immersion time is generally inversely proportional, and when the temperature of the bath is high, the immersion time is shortened to obtain a good quality nickel or nickel alloy. A plating layer is formed on the surface of the steel material.

  Furthermore, the electroless plating bath may contain additives such as stabilizers and brighteners in addition to the non-ferrous metal salt aqueous solution.

  The third step is not particularly limited as long as it is a third step in which a zinc plating layer is formed by electrolytic plating on the upper surface of the nickel or nickel alloy plating layer. As an example, the steel material on which the nickel or nickel alloy plating layer is formed is immersed in an electrolytic plating bath filled with the zinc metal salt aqueous solution, and the steel material is used as a cathode, and the bath is used as an anode. There is a step of performing plating. A known technique may be applied to the electrolytic plating process in the third step.

  The zinc may be replaced with a metal that can be electroplated. As the metal, for example, one or more metals selected from the group of nickel, magnesium, manganese, chromium, cobalt, aluminum, and copper, or an alloy of metals containing two or more metals, for example, iron-zinc alloys And iron-nickel alloys. In addition, when the said zinc is employ | adopted, it is preferable from a viewpoint of anticorrosion property, decorating property, and cost.

  Here, in the case of performing electrolytic plating with zinc, for example, an aqueous solution in which zinc hydroxide is dissolved in water is employed as the metal salt aqueous solution in the electrolytic plating.

  Further, the concentration of the metal salt in the zinc metal salt aqueous solution is appropriately changed in design according to the type of zinc, the temperature of the bath, and the immersion time. For example, the zinc salt is 0.5 wt% to 2.0 wt%. Within the range of wt% is preferred.

  Here, it is particularly preferable that a plating layer of nickel or an alloy thereof is formed by the electroless plating treatment, and a zinc plating layer is formed by the electrolytic plating treatment. This is because the nickel or its alloy and the zinc are compatible with each other in the plating process, so that the zinc electroplating layer can be uniformly formed on the surface of the electroless plating layer of the nickel or its alloy. It becomes possible.

  The thickness of the zinc plating layer is not particularly limited, but is preferably 5 μm or more, for example, and preferably within a range of 5 μm to 10 μm from the viewpoint of cost performance. Further, the temperature of the electrolytic plating bath is appropriately changed according to the type of the zinc and the type of the metal salt aqueous solution, but is preferably within a range of room temperature, for example, 20 degrees to 35 degrees. The immersion time (treatment time) is preferably in the range of 20 minutes to 60 minutes.

  In addition, the relationship between the bath temperature of the electrolytic plating and the immersion time is generally an inversely proportional relationship, similar to the electroless plating.

  In addition to the zinc metal salt aqueous solution, additives such as stabilizers and brighteners may be contained in the electrolytic plating bath in the same manner as the above-described electroless plating bath.

  Further, a water wash (step) for washing the steel material after the treatment can be appropriately provided between the steps from the first step to the third step.

  Now, in the electrogalvanizing method according to the present invention, the plating process is basically completed once from the first step to the third step, but in order to add additional value to the steel material after the plating process, A known secondary processing (step) may be added as appropriate.

  For example, in the electrogalvanizing treatment method according to the present invention, after the third step is completed, a fourth chromium layer is formed on the upper surface of the metal plating layer of the steel material by a chromate treatment method (chemical conversion treatment). It is preferable to include a step (FIG. 1: S104).

  In the fourth step, for example, the steel material on which the zinc plating layer is formed is immersed in a chromate tank filled with an aqueous metal salt solution of chromic acid and subjected to chemical conversion treatment. If comprised in this way, it will become possible to delay the corrosion (oxidation) of the said zinc plating layer, and it will become possible to improve the corrosion resistance of the said whole steel material remarkably. A known technique may be applied to the chromate treatment method in the fourth step.

  Further, in the electrogalvanizing method according to the present invention, when the fourth step is completed, a fifth step of drying the steel material on which the chromium layer is formed by a predetermined dryer (FIG. 1: S105). And a sixth step (FIG. 1: S106) for inspecting whether or not the steel material has no defect. Thereby, the steel material after completion of the inspection becomes a final product.

  Moreover, the steel material that is the object of the plating electrozinc treatment method according to the present invention is not particularly limited as long as it is a steel material that causes hydrogen embrittlement, but as the steel material, for example, carbon steel material containing carbon, high-tensile steel And ultra high strength steel. Further, the shape of the steel material is not particularly limited. Furthermore, the use of the steel material is not particularly limited, and examples thereof include uses such as aircraft parts, automobile parts, storage members, and fastening members such as bolts and nuts.

<Electrogalvanizing equipment>
The electrogalvanizing apparatus according to the present invention is not particularly limited as long as the above-described electrogalvanizing method can be embodied, and the simplest structure includes the following electrogalvanizing apparatus. .

  That is, the electrogalvanizing apparatus 100 according to the present invention is an electrogalvanizing apparatus that performs plating on a steel material. As shown in FIG. 2, the surface of the steel material is subjected to blasting to roughen the surface. An electroless plating treatment unit 102 for forming a plating layer of nickel or a nickel alloy for preventing hydrogen atoms from entering on the upper surface of the rough surface of the processing part 101, the steel material, and a plating layer of the nickel or nickel alloy And an electroplating processing unit 103 for forming a zinc plating layer by electroplating. The blast processing unit 101, the electroless plating processing unit 102, and the electrolytic plating processing unit 103 are a series of processing apparatuses.

  The electrogalvanizing apparatus 100 according to the present invention is mainly configured by arranging the above-described blast processing unit 101, electroless plating processing unit 102, and electrolytic plating processing unit 103 in series in this order on a line. The plating process is performed by the blast processing unit 101, the electroless plating processing unit 102, and the electrolytic plating processing unit 103.

  A specific procedure will be described. First, a steel material to be plated is transported to a blast processing unit 101 of the electrogalvanizing apparatus 100 by a first transport unit (not shown) such as a hoist. Here, as the blast processing unit 101, as shown in FIG. 3, a general shot blasting apparatus is employed.

  Next, when the surface of the steel material is roughened by the shot blasting apparatus, an electrolysis provided between the blasting processing unit 101 and the electroless plating processing unit 102 by a second transport unit (not shown). After being immersed in a degreasing tank and surface-adjusted, it is immersed in a first water-washing tank and washed with water. The number of times of washing with water is not limited, but is within a range of 1 to 3 times, for example, 2 times. Moreover, the said water washing process is suitably inserted between various plating processes so that it may mention later.

  Here, a known processing lot calculation unit may be arranged immediately after the shot blasting apparatus, and the weight, surface area, density, and the like of the roughened steel material may be calculated for each steel material.

  Then, the washed steel material is conveyed to the electroless plating treatment unit 102 by the second conveyance unit. Here, as shown in FIG. 4, the electroless plating treatment unit 102 employs an electroless plating tank filled with the nickel or nickel alloy metal salt aqueous solution. When the steel material is immersed in the electroless plating tank for a predetermined time, the nickel or nickel alloy plating layer is formed on the surface of the steel material, and when the electroless plating process is completed, a third transport unit (not shown) The steel material on which the nickel or nickel alloy plating layer is formed is immersed in a second water rinsing tank provided between the electroless plating treatment unit 102 and the electrolytic plating treatment unit 103, and is washed with water. . The number of times of washing with water is not limited, but is within a range of 1 to 3 times, for example, 2 times.

  Then, the washed steel material is conveyed to the electrolytic plating treatment unit 103 by the third conveyance unit. Here, as shown in FIG. 5, the electrolytic plating treatment unit 103 employs an electrolytic plating tank filled with the zinc metal salt aqueous solution. The side surface 103a of the electrolytic plating tank functions as an anode, and the long metal rod 103b hung on the upper surface of the electrolytic plating tank functions as a cathode. Naturally, the side surface 103a of the electrolytic plating tank and the metal rod 103b are electrically insulated. The third transport unit holds the steel material with a metal holding unit (not shown), and the steel unit held by the holding unit becomes a cathode by hanging the holding unit on the metal rod 103b of the electrolytic plating tank, A predetermined current is applied between the anode and the cathode for a predetermined time, and electrolytic plating is performed. The electrolytic plating treatment unit 103 is not limited to the above-described method using an electrolytic plating tank, and may be, for example, a barrel plating method performed in a rotating container or a stationary plating method performed by attaching an article to a cathode.

Here, when the applied current is adjusted so that the current density of the steel material is within a range of 0.5 A / dm ^{2 to} 3.0 A / dm ² , for example, zinc plating of good quality electrolytic plating is performed. A layer can be formed on the surface of the steel material.

  When the zinc plating layer is formed on the surface of the steel material by the electrolytic plating, the steel material is transported to the outside by a fourth transport section (not shown). By such a series of processes, the steel material is completely plated.

  Here, although it is a general process, for example, a third water washing tank is provided immediately after the electrolytic plating treatment unit 103, and the steel material after the electrolytic plating process is immersed in the third water washing tank, Washed with water. Moreover, although the frequency | count of the said water washing does not have a restriction | limiting, it is in the range of 1-3 times, for example, 2 times.

  As described above, in the electrogalvanizing apparatus 100 according to the present invention, the blast processing unit 101, the electroless plating processing unit 102, and the electroplating processing unit 103 are basically configured, and a conventionally required baking processing unit is provided. Make it unnecessary. Thereby, not only the cost and processing time required for the baking process can be reduced, but also the management cost and the like required for the baking processing part can be reduced. Conventionally, even when the baking treatment is performed, removal of hydrogen embrittlement is incomplete, and there is a problem that leads to delayed fracture.

  Furthermore, by configuring the blast processing unit 101, electroless plating processing unit 102, and electrolytic plating processing unit 103 of the electrogalvanizing apparatus 100 according to the present invention on a series line, the management of the plating process is facilitated and managed. The number of operators (operators) can be reduced, and cost performance can be improved.

  Further, immediately after the electrolytic plating processing unit 103 of the electrogalvanizing processing apparatus 100 shown in FIG. 2, for example, a plating processing unit (for example, chromate processing unit) for secondary processing, a drying unit, and an inspection unit are added. Is preferred.

  Here, in the case of adding the plating processing unit, a known activation processing unit is provided immediately before the plating processing unit, in other words, immediately after the electrolytic plating processing unit 103, and in the bathtub of the activation processing unit, You may comprise so that the steel material after the said electrolytic plating process may be immersed, and the zinc plating layer in the said steel material may be activated. By activating the zinc plating layer, it is possible to perform secondary processing (chromate treatment) by the subsequent plating processing unit uniformly and with high quality.

  In addition, it is known that the activation processing unit is usually installed corresponding to the plating processing unit related to chromate processing, and the aqueous solution of the activation processing unit is appropriately designed according to the type of the metal. Although changed, the aqueous solution of the said activation process part is a 5.0 weight% nitric acid aqueous solution, for example.

  In addition, in the case where the electrogalvanizing apparatus according to the present invention is newly constructed in accordance with the above, for example, the following configuration can be considered. That is, the blast processing unit 101, the processing lot calculation unit, the electrolytic degreasing unit, two washing baths, an electroless plating processing unit 102, two washing baths, an electrolytic plating unit 103, two washing baths, and the activation treatment An electrogalvanizing apparatus including a chromate treatment unit for the chromate treatment, two wash baths, the drying unit, and the inspection unit.

<Examples, comparative examples, etc.>
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(1) Steel materials As steel materials, carbon is 0.87 wt%, silicon is 0.19 wt%, manganese is 0.41 wt%, phosphorus is 0.11 wt%, sulfur is 0.009 wt%, and copper is 0 Carbon steel (SK85) having a composition of 0.01% by weight, nickel of 0.02% by weight, chromium of 0.13% by weight and the balance of iron and impurities was used. Here, when plating the steel material, a test piece having a thickness of 0.5 mm × length of 70.0 mm was cut out from the steel material and used. Further, six types of hardness (HV) of the steel material were prepared: 436 HV, 481 HV, 508 HV, 575 HV, and 675 HV.

(2) Examples, Comparative Examples, etc. The steel material of Example 1 according to the present invention was manufactured by the following procedure. As shown in FIG. 1, first, the steel material was subjected to shot blasting using a shot blasting apparatus shown in FIG. 3 (FIG .: S101) to roughen the surface of the steel material, and then electrolytically degreased and washed with water.

  Next, by immersing the roughened steel material in an electroless plating bath shown in FIG. 4, a nickel alloy plating layer that prevents intrusion of hydrogen atoms on the upper surface of the rough surface of the steel material. It was formed by electroless plating (FIG. 1: S102).

  Here, the bath composition of the electroless plating bath is an aqueous electrolyte solution of nickel, 0.5% by weight of salt, and 8% to 9% by weight of hypophosphite, and the electroless plating bath. The temperature of was 80 to 85 degrees. Further, the steel material was immersed in an electroless plating bath for 10 minutes to form a nickel alloy plating layer having a thickness of 3 μm over the entire surface of the steel material. The plating layer is a nickel phosphorus plating layer mainly composed of nickel.

  Next, the steel material after the electroless plating is washed with water, and the steel material is immersed in a bath of electrolytic plating shown in FIG. 5 filled with an aqueous solution of zinc metal salt. The steel material is used as a cathode and the bath is used as an anode. Electricity was applied, and the zinc plating layer was formed on the upper surface of the nickel alloy plating layer by electrolytic plating (FIG. 1: S103).

Here, the bath composition of the electrolytic plating bath was an aqueous electrolyte solution containing 1.5% by weight of zinc salt (zinc hydroxide), and the temperature of the electrolytic plating bath was 25 degrees. Further, with the steel material immersed in an electrolytic plating bath, the current density to the steel material was set to 1.3 A / dm ² , and electrolytic plating was performed for 48 minutes to form a zinc plating layer having a thickness of 8 μm. It was formed over the entire surface of the nickel alloy plating layer. The steel material on which the zinc plating layer was formed was used as the steel material of Example 1.

  In addition, the same process was performed with six types of steel materials having hardness (HV) of 436 HV, 481 HV, 508 HV, 575 HV, and 675 HV.

  Moreover, the steel material of Example 2 changed the thickness of the non-ferrous plating layer formed in the said steel materials from 3 micrometers to 1 micrometer by adjusting the immersion time to the bathtub of the electroless plating of the steel materials in Example 1. Except for this, it was produced by the same treatment as in Example 1.

  Moreover, the steel material of Example 3 changed the thickness of the nonferrous plating layer formed in the said steel material from 3 micrometers to 5 micrometers by adjusting the immersion time in the bathtub of the electroless plating of the steel material in Example 1. Except for this, it was produced by the same treatment as in Example 1.

  Moreover, the steel material of the comparative example 1 which concerns on this invention was manufactured with the following procedures. As shown in FIG. 7, first, the steel material was immersed in a bath for electrolytic degreasing to give the steel material an alkaline degreasing treatment (FIG. 7: S202).

  Here, the bath composition of the electrolytic degreasing bath is an aqueous solution in which sodium silicate is 7 wt% to 10 wt%, the temperature of the electrolytic degreasing bath is 60 degrees, and the steel is It was immersed in an alkaline degreasing bath for 30 minutes.

  Next, the steel material after the electrolytic degreasing treatment was washed with water, and the steel material was immersed in a pickling bath to perform pickling treatment (FIG. 7: S202).

  Here, the bath composition of the pickling bath is an aqueous solution containing 18% by weight of hydrochloric acid, the temperature of the pickling bath is room temperature, and the steel material is stored in the pickling bath for 15 minutes. Soaked.

  Then, the surface-roughened steel material after the pickling treatment is washed with water, and the steel material is immersed in an electrolytic plating bath filled with an aqueous zinc metal salt solution. The steel material serves as a cathode and the bath serves as an anode. Energization was performed, and the zinc plating layer was formed on the rough surface of the steel by electrolytic plating (FIG. 7: S203).

  Here, each condition of the electrolytic plating bath was the same as in Example 1, and a zinc plating layer having a thickness of 8 μm was formed over the entire rough surface of the steel material.

  Furthermore, the steel material after the electrolytic plating was put into a dryer and subjected to baking treatment at 210 degrees for 4 hours (FIG. 7: S204). The steel material after the baking treatment was used as the steel material of Comparative Example 1. In addition, the same process was performed with six types of steel materials having a hardness (HV) of 436 HV, 481 HV, 508 HV, 575 HV, and 675 HV.

  Further, the steel material of Reference Example 1 according to the present invention was produced by the same treatment as in Example 1 except that the electroplating treatment was omitted (eliminated) after the electroless plating treatment in Example 1. . In this case, the steel material of Reference Example 1 has only a nickel phosphorus (nickel alloy) plating layer formed on the surface thereof.

  The steel material of Reference Example 2 was produced by the same treatment as in Example 2 except that the electroless plating treatment in Example 2 was performed and then the electrolytic plating treatment was omitted.

  The steel material of Reference Example 3 was produced by the same treatment as in Example 3 except that the electroless plating treatment in Example 3 was performed and then the electrolytic plating treatment was omitted.

  The steel material of Reference Example 4 was treated in the same manner as in Example 1 except that the electroless plating process was omitted (eliminated) after the blasting process in Example 1 and the electroplating process was performed. Manufactured by. In this case, only the zinc plating layer is formed on the surface of the steel material of Reference Example 4.

(3) Measuring method of hydrogen embrittlement degree (%) The hydrogen embrittlement degree (%) of a steel material subjected to a predetermined plating treatment is a universal deep drawing test in accordance with the method prescribed in the JIS Z 2247 B method. Measured using a machine. First, the steel material is fixed to a universal deep-drawing tester, and a semi-circular steel pushing ball is pressed against the steel material to bend the steel material. Then, the steel material pushing ball is pressed until the curved steel material cracks (breaks), and the height (distance) of movement of the steel material pushing ball from the start of pushing of the steel material pushing ball to the breaking of the steel material Was defined as Erichsen height H (mm).

The hydrogen embrittlement degree X (%) was determined by measuring the Erichsen height H ₀ (mm) of the steel material before the plating treatment and the Erichsen height H _p (mm) of the steel material after the plating treatment, respectively. It was calculated by substituting into the equation.
X (%) = (H ₀ −H _p ) / H ₀ × 100

The hydrogen embrittlement degree X (%) is, as is clear from the above formula, the Erichsen height H _p (mm) of the steel material after the plating treatment is equal to the Erichsen height H ₀ ( mm), it is understood that it is close to zero. That is, when hydrogen atoms enter the steel material after the plating treatment, the steel material after the plating treatment becomes brittle due to hydrogen embrittlement, and the Erichsen height H _p (mm) is equal to Erichsen of the steel material before the plating treatment. Naturally, it becomes lower than the height H ₀ (mm). The embrittlement corresponds to the hydrogen embrittlement degree X (%).

(4) Measurement Result of Hydrogen Embrittlement FIG. 6 is a diagram illustrating an example of the result of hydrogen embrittlement in Examples, Reference Examples, and Comparative Examples. As shown in FIG. 6, the hydrogen embrittlement degree X (%) of Examples 1 to 3 is 0% despite no baking treatment, and no hydrogen embrittlement has occurred. Understood.

  In Examples 1 to 3, the pickling treatment is replaced with a blast treatment, and a nickel alloy (nickel-phosphorus) that prevents intrusion of hydrogen atoms by electroless plating treatment in which no hydrogen atoms penetrate before the electroplating treatment. The alloy layer is provided on the entire surface of the steel material, and it is assumed that the nickel alloy plating layer prevented the intrusion of hydrogen atoms even after the subsequent electroplating of zinc in which hydrogen atoms are generated. .

  On the other hand, the hydrogen embrittlement degree X (%) of Comparative Example 1 is understood to be that hydrogen atoms are invaded by the electrolytic plating process due to the electrolytic plating process despite the baking process. The

  This is because the baking treatment is usually performed for the purpose of diffusing hydrogen atoms that have penetrated into the steel material to the outside, and the zinc plating layer formed by the electrolytic plating already exists on the surface of the steel material. It is speculated that the metal plating layer inhibits external diffusion of internal hydrogen atoms. Furthermore, it is understood that the effect of preventing hydrogen embrittlement by the baking treatment is not certain. This is estimated to lead to delayed fracture.

  In addition, the hydrogen embrittlement degree X (%) of Reference Examples 1 to 3 is 0% even when the blast treatment and the electroless plating treatment are performed and the electrolytic plating treatment is not performed, and hydrogen embrittlement occurs at all. It is understood that they are not. Thereby, once the nickel alloy plating layer is formed on the surface of the steel material, any kind of metal plating layer is formed by electrolytic plating on the upper surface of the nickel alloy plating layer. It is estimated that the hydrogen embrittlement degree X (%) of the steel material is 0%.

  Further, the hydrogen embrittlement degree X (%) of Reference Example 4 indicates that, when the nickel alloy plating layer does not exist, as in Comparative Example 1, hydrogen atoms enter due to the electrolytic plating treatment and cause hydrogen embrittlement. It is understood that

(5) Cost comparison The cost of Example 1 per kg of the steel material and the cost of Comparative Example 1 were calculated and compared. Here, when calculating the cost, since the electroplating process is common in Example 1 and Comparative Example 1, the cost was calculated and compared for the different processes.

  First, the cost required for the shot blasting process in Example 1 is 0.42 yen / kg for the shot grain consumption cost, 0.83 yen / kg for the shot machine amortization cost, and the shot machine maintenance management cost is 1. Since it is 17 yen / kg, it is 2.42 yen / kg in total. The cost required for the electroless plating process in Example 1 is 5.15 yen / kg for the electroless plating solution chemicals, and the depreciation cost for the electroless plating tank is 0.42 yen / kg. Since the tank maintenance cost is 0.83 yen / kg, the total is 6.40 yen / kg. Therefore, the cost required for the shot blasting process and the electroless plating process in Example 1 is 8.82 yen / kg.

  On the other hand, the cost required for the pickling treatment in Comparative Example 1 is 0.17 yen / kg for the pickling chemical and the depreciation cost for the pickling tank is 0.14 yen / kg. Since the cost is 0.15 yen / kg, the total of them is 0.46 yen / kg. Moreover, the cost required for the baking process in Comparative Example 1 is a heat source (propane gas) cost of 10.67 yen / kg, a baking furnace depreciation cost of 1.38 yen / kg, and a baking furnace maintenance management cost of 2 50 yen / kg. Therefore, the cost required for the pickling process and the baking process in Comparative Example 1 is 15.01 yen / kg.

  Comparing the cost of Example 1 and the cost of Comparative Example 1, it is understood that the cost of Example 1 is cheaper by 6.19 yen / kg than the cost of Comparative Example 1. Therefore, it is understood that the electrogalvanizing method of Example 1 is superior in cost performance as compared with the electrogalvanizing method of Comparative Example 1 which is a conventional technique.

  In Comparative Example 1, the baking process requires a large amount of heat (propane gas), and a large amount of carbon dioxide is released due to the amount of heat. On the other hand, in Example 1, since the baking process is omitted, the carbon dioxide cannot be released. Therefore, it is understood that the electrogalvanizing method of Example 1 greatly contributes to the reduction of carbon dioxide as an environmentally hazardous substance as compared with the electrogalvanizing method of Comparative Example 1.

  In the conventional baking processing corresponding to Comparative Example 1, for example, when processing for 2 hours, it is necessary to operate the baking processing apparatus for at least 4 hours including temperature rise and fall. For example, when processing for 4 hours, it is necessary to operate the baking processing apparatus for at least 7 hours. As described above, in the baking process, the cost and the processing time required for adjusting the temperature, and the accompanying carbon dioxide emission are remarkable. Therefore, the electrogalvanizing method and the electrogalvanizing apparatus according to the present invention have their costs and the like. Can be reduced comprehensively, and has an epoch-making effect.

  Thus, in the electrogalvanizing method according to the present invention, the electrogalvanizing method for plating a steel material, the first step of roughening the surface of the steel material by blasting, A second step of forming a plating layer of nickel or a nickel alloy for preventing intrusion of hydrogen atoms on the upper surface of the rough surface of the steel material by electroless plating; and plating of zinc on the upper surface of the plating layer of the nickel or nickel alloy And a third step of forming the layer by electrolytic plating.

  This makes it possible to eliminate the possibility of hydrogen embrittlement (delayed fracture) in the steel material after plating due to electrogalvanizing treatment, improve cost performance, and contribute to reducing environmental impact. .

  Further, the electrogalvanizing apparatus 100 according to the present invention is an electrogalvanizing apparatus for plating a steel material, and a blast processing unit 101 for roughening the surface of the steel material by blasting the surface, and the steel material An electroless plating treatment part 102 for forming a nickel or nickel alloy plating layer for preventing the entry of hydrogen atoms by electroless plating on the upper surface of the rough surface, and zinc on the upper surface of the nickel or nickel alloy plating layer. And an electroplating processing unit 103 for forming a plating layer by electroplating. Thereby, it becomes possible to obtain the same effect as the electrogalvanizing method described above.

  Further, the steel material manufactured by the electrogalvanizing method or the electrogalvanizing apparatus 100 according to the present invention has a hydrogen embrittlement degree X (%) of 0% as described above. Brittleness (delayed fracture) does not occur, and it can be provided as a steel material excellent in safety and quality.

  As described above, the electrogalvanizing method and the electrogalvanizing apparatus according to the present invention are used in various fields such as the aviation field, the automobile field, the fuel cell field, and the hydrogen energy field. It is useful as a method and an electrogalvanizing apparatus. In addition, the possibility of hydrogen embrittlement (delayed fracture) due to electrogalvanizing treatment is zero, and it is effective as an electrogalvanizing treatment method and electrogalvanizing treatment apparatus that are excellent in cost performance and environmental load reduction.

DESCRIPTION OF SYMBOLS 100 Electrogalvanization processing apparatus 101 Blasting processing part 102 Electroless plating processing part 103 Electrolytic plating processing part

Claims (2)

An electrogalvanizing method for plating a steel material,
A first step of roughening the surface of the steel material by blasting;
A second step of forming a plating layer of nickel or a nickel alloy that prevents intrusion of hydrogen atoms on the upper surface of the rough surface of the steel material by electroless plating;
By immersing the steel material on which the nickel or nickel alloy plating layer is formed in an electrolytic plating bath filled with an aqueous solution of zinc metal salt, the steel material is used as a cathode, and the bath is used as an anode for electrolytic plating. , on the upper surface of the plating layer of the nickel or nickel alloy, electrolytic zinc plating method, characterized in that it comprises a third step of forming a plating layer of the zinc electroplating. An electrogalvanizing apparatus for plating steel materials,
A blasting portion for roughening the surface of the steel material by blasting;
On the upper surface of the rough surface of the steel material, an electroless plating treatment part that forms a plating layer of nickel or a nickel alloy that prevents intrusion of hydrogen atoms by electroless plating,
By immersing the steel material on which the nickel or nickel alloy plating layer is formed in an electrolytic plating bath filled with an aqueous solution of zinc metal salt, the steel material is used as a cathode, and the bath is used as an anode for electrolytic plating. , on the upper surface of the plating layer of the nickel or nickel alloy, electrolytic zinc plating apparatus, characterized in that it comprises a electrolytic plating process unit for forming a plated layer of the zinc electroplating.