Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
  • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
  • H01F1/147—Alloys characterised by their composition
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
  • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
  • B05D3/0254—After-treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
  • B05D7/14—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to metal, e.g. car bodies
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/32—Phosphorus-containing compounds
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
  • C21D1/76—Adjusting the composition of the atmosphere
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
  • C21D8/12—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties
  • C21D8/1277—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of articles with special electromagnetic properties involving a particular surface treatment
  • C21D8/1283—Application of a separating or insulating coating
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/12—Orthophosphates containing zinc cations
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/20—Orthophosphates containing aluminium cations
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
  • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
  • C23C22/07—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 containing phosphates
  • C23C22/08—Orthophosphates
  • C23C22/22—Orthophosphates containing alkaline earth metal cations
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
• • C—CHEMISTRY; METALLURGY
  • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
  • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
  • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
  • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
  • C23C22/74—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process for obtaining burned-in conversion coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
  • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/32—Phosphorus-containing compounds
  • C08K2003/321—Phosphates
  • C08K2003/327—Aluminium phosphate
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/32—Phosphorus-containing compounds
  • C08K2003/321—Phosphates
  • C08K2003/328—Phosphates of heavy metals

Definitions

• the present invention relates to a non-oriented electrical steel sheet and a method for manufacturing the same.
• the non-oriented electrical steel sheet is used as an iron core material for a rotating machine in the form of a so-called laminated body composed of a large number of steel sheets laminated.
• a non-directional electromagnetic steel plate is used as an iron core for a rotating machine, if a current called an eddy current is induced in the normal direction of the laminated steel plate surface, the efficiency of the rotating machine decreases. .. Therefore, in order to prevent the generation of eddy currents, an insulating film is generally formed on the surface of the non-oriented electrical steel sheet.
• this insulating film In addition to preventing the generation of eddy currents, this insulating film also has the function of protecting the non-oriented electrical steel sheet itself, which is composed of iron-based elements, from rusting, that is, corrosion. Therefore, it has been common to form a chromate-based film having a strong corrosion-preventing effect on the surface of non-oriented electrical steel sheets.
• Patent Document 1 discloses that a film agent containing one or more of Al phosphate, Ca phosphate, and Zn phosphate is used as an inorganic substance.
• Patent Document 2 phosphoric acid Al used as the inorganic compound in the coating, phosphate Ca, the phosphate Zn, respectively, Al 2 O 3 / H 3 PO 4 molar ratio, CaO / H 3 PO 4 molar ratio, ZnO / It is disclosed to specify the H 3 PO 4 molar ratio.
• Patent Document 3 discloses that Al-first phosphate and organic acid salts of Al, Mg, Ca, and Zn are used.
• Patent Documents 4 to 6 disclose that a metal phosphate salt containing a Zn component is used.
• the above-mentioned technique was related to the inorganic component among the film constituents.
• a technique focusing on the organic component of the film component a proposal has been made in which a chelate-forming compound such as a phosphonic acid system is used as the film component.
• Patent Document 7 discloses a technique for adding a phosphonic acid-based or carboxylic acid-based chelate-forming compound to a coating liquid.
• Patent Document 8 discloses a technique of using a phosphonic acid-based or carboxylic acid-based chelate-forming compound as an anti-yellowing agent.
• Patent Document 9 discloses a technique using titanium hydrofluoric acid or zircon hydrofluoric acid in addition to a phosphonic acid-based or carboxylic acid-based chelate-forming compound.
• Patent Document 10 discloses a technique for adding a phosphonic acid-based or carboxylic acid-based chelate-forming compound to a coating liquid.
• Patent Document 11 discloses a technique using a titanium chelate or the like.
• Patent Document 12 discloses a technique of using a phosphonic acid-based or carboxylic acid-based chelate compound after Ni-plating prior to coating.
• Patent Document 13 discloses a technique for adding a polyamine in addition to a phosphonic acid-based or carboxylic acid-based chelate-forming compound to a coating liquid.
• Patent Document 14 discloses that the Fe area fraction in a cross section of a film obtained by using a transmission electron microscope or the like is specified.
• Patent Document 15 discloses that the relationship between the ratio of P in the film determined by X-ray photoelectron spectroscopy and the ratio of Fe bonded to O is defined.
• Patent Document 16 discloses that the ratio of Fe / P in the film is specified.
• Patent Document 17 discloses that the integrated intensity ratio of P in nuclear magnetic resonance spectroscopy is specified.
• Patent Document 18 discloses that a carboxylic acid is contained in a film.
• Patent Document 19 discloses that the amount of phosphoric acid in the film is specified for each type.
• Patent Document 20 discloses that the ratio of Fe 3+ to the total Fe in the film is specified.
• Patent Document 21 discloses that the concentration amount of the divalent metal in the film is specified.
• the electrical steel sheets are formed into a predetermined shape.
• the most common molding method is a method of punching an electromagnetic steel sheet using a die. Since the base steel sheet is exposed on the cut surface of the electromagnetic steel sheet, the rust preventive effect of the insulating film cannot be obtained.
• the cut surface of the electrical steel sheet may be stored as it is for a considerable period of time after punching until the electrical steel sheet is transferred to the next process. During this storage, the cut surface may be corroded.
• Patent Document 22 proposes a method of adding a carboxylic acid compound having 2 to 50 carbon atoms to a coating liquid for forming an insulating film.
• 2016/10405 International Publication No. 2016/10407 International Publication No. 2016/10512 Japanese Unexamined Patent Publication No. 2016-125141 Japanese Unexamined Patent Publication No. 2016-125142 Japanese Unexamined Patent Publication No. 2016-138333 International Publication No. 2016/194520 International Publication No. 2016/136515
• the chelate compound when used as a component of the coating liquid for film formation, there is a problem that the cost increases.
• the price competition for non-oriented electrical steel sheets is fierce, and the cost that can be spent on the coating liquid for forming the insulating film is very limited. Therefore, it has been inevitably desired that the raw material used for film formation has a low cost.
• the present inventors can stably exhibit the excellent corrosion resistance of Zn even on the "cut surface of steel sheet" without using expensive carboxylic acid compounds and the like. Worked on the development of grain-oriented electrical steel sheets and their manufacturing methods.
• the present invention solves the above-mentioned problems, and in a hot and humid environment and a salt-adhered environment without using an environmentally hazardous substance called a chromate-based compound and without using an expensive organic compound such as a carboxylic acid-based compound.
• An object of the present invention is to provide a non-directional electromagnetic steel sheet having excellent corrosion resistance on a cut surface of a steel sheet and a method for producing the same.
• the present invention has been made to solve the above problems, and the gist of the following non-oriented electrical steel sheets and their manufacturing methods is.
• the non-directional electromagnetic steel sheet according to an embodiment of the present invention includes a base steel sheet and a composite film of a Zn-containing phosphate and an organic resin formed on the surface of the base steel sheet.
• the Zn content in the composite film is 10 mg / m 2 or more per side, and the product of the oxygen content in the base steel sheet and the plate thickness of the base steel sheet is 50 ppm ⁇ mm or less.
• the composite film may further contain one or more selected from the group consisting of Al, Mg, and Ca.
• the organic resin is composed of acrylic resin, styrene resin, acrylic-styrene resin, epoxy resin, polyester resin, phenol resin, and urethane resin. It may contain one or more selected from the group.
• the method for producing a non-directional electromagnetic steel sheet according to another embodiment of the present invention includes a step of applying a coating liquid containing a Zn-containing phosphate and an organic resin to the surface of the base steel sheet, and the coating.
• the liquid is baked in an atmosphere having an oxygen concentration of 30% or less under the conditions that the maximum reaching temperature is in the range of 250 to 450 ° C. and the tensile strength applied to the base steel sheet is 15 to 60 N / mm 2.
• a step of forming a composite film having a Zn content of 10 mg / m 2 or more per side is provided.
• the coating liquid may further contain one or more selected from the group consisting of Al, Mg, and Ca.
• the organic resin is an acrylic resin, a styrene resin, an acrylic-styrene resin, an epoxy resin, a polyester resin, a phenol resin, and It may contain one or more selected from the group consisting of urethane resins.
• the excellent corrosion resistance of Zn can be obtained even on the cut surface of a steel sheet without using an environmentally hazardous substance such as a chromate-based compound and an expensive organic compound represented by a carboxylic acid-based compound as a coating material. It is possible to manufacture non-directional electromagnetic steel sheets that can be exhibited.
• a film or the like formed on the surface of the steel sheet may adhere to the cut surface of the steel sheet. This is called the "hanging effect".
• the present inventors focused on the relationship between the "dripping effect” and the corrosion resistance of the cut surface of the steel sheet, and further studied.
• the corrosion resistance of the steel sheet is considered to be determined by the presence and quality of this corrosion product. That is, when a corrosion product that suppresses the permeation of water and salt is formed on the cut surface of the steel sheet, contact / invasion of water and salt into the steel sheet itself is blocked. Therefore, the corrosion of the steel sheet itself is suppressed, and as a result, the generation of rust is suppressed in the salt spray test.
• a chelate compound may be contained in the film for the purpose of improving the adhesion between the film and the base steel sheet.
• the adhesion is too high, the film is less likely to peel off and the "dripping effect" is less likely to be obtained.
• the corrosion resistance of the cut surface deteriorates when the oxide layer is formed on the surface of the base steel sheet. From this, if an oxide layer is present on the surface of the base steel sheet, the oxide layer is peeled off and adheres to the cut surface when cutting with a shearing machine or punching with a die, and in the salt spray test, water and salt It is presumed that when placed in a moist environment containing water and salt, it forms a corrosion product with poor corrosion resistance, which is easily permeated by water and salt.
• Non-oriented electrical steel sheet The non-oriented electrical steel sheet according to the present embodiment includes a base steel sheet and an insulating film formed on the surface of the base steel sheet.
• the insulating coatings of non-directional electromagnetic steel sheets are roughly classified into all-organic coatings (all coatings are composed of organic substances), inorganic coatings (all coatings are composed of inorganic substances), and composite coatings (those in which all coatings are composed of inorganic substances).
• the film is composed of a combination of organic and inorganic substances, and is also called a semi-organic film).
• the insulating film of the non-oriented electrical steel sheet according to this embodiment is a composite film.
• the inorganic substance in the composite film phosphate, colloidal silica, alumina sol, zirconia sol and the like have been proposed.
• phosphate colloidal silica, alumina sol, zirconia sol and the like.
• the present invention is based on the technical idea of improving the corrosion resistance by eluting the Zn component adhering to the cut surface, and thus Zn-containing phosphate is essential. That is, in the present invention, the composite film contains a Zn-containing phosphate and an organic resin.
• the Zn content in the composite film is 10 mg / m 2 or more per side.
• the Zn content per one side means the average value of the Zn content (mg / m 2 ) per unit area of the composite film on both the front surface and the back surface of the base steel sheet.
• the Zn content in the composite film is less than 10 mg / m 2, it is difficult to generate a Zn-containing corrosion product having good corrosion resistance from the film drooping on the cut surface of the steel sheet. As a result, the corrosion resistance of the cut surface of the steel sheet is inferior, and red rust is generated more frequently.
• the Zn content in the composite film is set to 10 mg / m 2 or more, a sufficient amount of Zn is eluted from the film drooping on the cut surface of the steel sheet. As a result, a corrosion product containing Zn having good corrosion resistance is formed, and the cut surface of the steel sheet is excellent in corrosion resistance, so that red rust is less likely to occur.
• the Zn content in the composite film is preferably 20 mg / m 2 or more, and more preferably 30 mg / m 2 or more per side.
• the Zn content in the composite film is measured by the following method. First, a non-oriented electrical steel sheet having a composite film is immersed in a methanol solution containing 5% by mass of bromine. Next, the non-oriented electrical steel sheet immersed in the solution is irradiated with ultrasonic waves to dissolve the base steel sheet, and the composite film component is filtered as a residue.
• the obtained residue is completely dissolved by the acid dissolution-alkali melting method to prepare an aqueous solution.
• this aqueous solution is analyzed by ICP (radio frequency inductively coupled plasma) -issued spectroscopic analysis, thereby quantifying the amount of Zn.
• the quantified amount of Zn is divided by the sample area of the non-oriented electrical steel sheet (the total area of the front and back surfaces of the base steel sheet) to convert it into the amount per unit area.
• JIS K 0116: 2014 "General rules for emission spectroscopic analysis" can be used.
• the product of the oxygen content of the base steel sheet and the plate thickness of the base steel sheet is 50 ppm ⁇ mm or less.
• the oxygen amount of the base steel sheet is a value obtained by analyzing the oxygen amount of the steel sheet after removing the composite film of the non-directional electromagnetic steel sheet by a predetermined means, and the unit thereof is It is ppm.
• the thickness of the base steel sheet is the thickness of the steel sheet after removing the composite film from the non-oriented electrical steel sheet, and its unit is mm.
• the present inventors have found that when an oxide layer is formed on the surface of the base steel sheet, the corrosion resistance of the cut surface deteriorates. In particular, it was found that a good correlation was observed between the salt spray corrosion resistance and the product of the oxygen content of the base steel sheet and the plate thickness.
• the surface of the base steel sheet before applying the coating liquid for forming a composite film and baking it is not oxidized. This is because the base steel sheet before applying the treatment liquid is annealed in an atmosphere having low oxidizing property. Therefore, the oxygen measured as the amount of oxygen in the base steel sheet is generated by the oxidation of the base steel sheet when the coating liquid is baked.
• the oxygen content of the base steel sheet is the mass ratio of oxygen in the sample to the total amount of the base steel sheet (that is, the average oxygen content in the sample).
• the surface of the base steel sheet of the non-oriented electrical steel sheet contains oxygen due to surface oxidation during baking, but the inside of the base steel sheet contains almost no oxygen. Therefore, when the oxygen content of the thin base steel sheet and the thick base steel sheet subjected to baking under the same conditions (that is, the degree of surface oxidation is almost the same) is measured by the above method, the base material having a thin plate thickness is measured.
• the amount of oxygen in the steel sheet is calculated to be larger than the amount of oxygen in the base steel sheet with a thin plate thickness.
• the present inventors decided to use a value obtained by multiplying the amount of oxygen in the base steel plate by the plate thickness (mm) of the base steel plate as an index for evaluating the degree of oxidation of the surface of the base steel plate. did. By multiplying the measured amount of oxygen by the plate thickness, it is possible to correct the influence of the plate thickness of the base steel plate on the measured value of the oxygen content of the base steel plate.
• the product of the amount of oxygen in the base steel sheet and the thickness of the base steel sheet is preferably 40 ppm ⁇ mm or less, and more preferably 30 ppm ⁇ mm or less.
• the amount of oxygen in the base steel sheet is measured by the following method. First, the non-oriented electrical steel sheet is boiled in a sodium hydroxide aqueous solution having a concentration of 50% for 30 minutes to remove the composite film from the base steel sheet. Next, the amount of oxygen in the remaining steel sheet is measured by JIS G 1239: 2014 "Iron and Steel-Oxygen Quantification Method-Inert Gas Melting-Infrared Absorption Method".
• the measurement accuracy of the oxygen content is taken into consideration, rounded off, and the result is a multiple of 5. Shall be displayed.
• the composite film may contain, for example, one or more selected from the group consisting of Al, Mg, and Ca. Like Zn, these elements are desired to be contained as phosphates. Considering the environmental load, it is not preferable that the composite film contains a chromic acid-based compound and a substance derived from the chromic acid compound. The content of the chromic acid-based compound and the substances derived from the chromic acid compound should be reduced as much as possible to meet the environmental standard, preferably 0% by mass.
• the organic resin is not particularly limited, but at least one selected from the group consisting of acrylic resin, styrene resin, acrylic-styrene resin, epoxy resin, polyester resin, phenol resin, and urethane resin is exemplified.
• a chelate compound such as a phosphonic acid compound or a carboxylic acid compound
• the adhesion between the film and the base steel sheet is improved, the film is less likely to peel off, and the "dripping effect" is achieved. May be difficult to obtain. Therefore, the chelating compound is not contained in the composite film of the present invention.
• the base steel sheet of the non-oriented electrical steel sheet according to the present embodiment is not particularly limited. This is because the improvement of corrosion resistance, which is a problem of the non-oriented electrical steel sheet according to the present embodiment, is achieved by the above-mentioned characteristics of the insulating film.
• the base steel sheet can be appropriately selected from ordinary steel sheets used as the base steel sheet of the non-oriented electrical steel sheet.
• the non-directional electromagnetic steel sheet according to the present embodiment includes a step of applying a coating liquid to the surface of the base steel sheet, and then a step of forming a composite film on the base steel sheet by baking the coating liquid. It can be manufactured by a manufacturing method.
• the coating liquid to be applied to the surface of the base steel sheet contains a phosphate aqueous solution and an organic resin aqueous dispersion. Further, the metal component in the aqueous phosphate solution contains a Zn component. After baking, it is necessary to prepare the components of the coating liquid so that the Zn content is 10 mg / m 2 or more per side. In addition to Zn, for example, one or more selected from the group consisting of Al, Mg, and Ca may be further contained, but the present invention is not limited thereto.
• organic resin is not particularly limited. Any type can be used as long as it does not form coarse agglomerates when mixed with an aqueous phosphate solution.
• Preferred organic resins include one or more selected from the group consisting of acrylic resins, styrene resins, acrylic-styrene resins, epoxy resins, polyester resins, phenol resins, urethane resins and the like.
• the ratio of the aqueous phosphate solution to the organic resin aqueous dispersion can be arbitrarily selected.
• the non-oriented electrical steel sheet in which an insulating film is formed by using a coating liquid that does not contain an organic resin aqueous dispersion tends to be inferior in punching property. Therefore, it is better to include the organic resin aqueous dispersion in the coating liquid.
• the blending ratio of the aqueous phosphate solution and the aqueous dispersion of the organic resin may be determined in consideration of the solid content concentration of each. As long as the blending ratio is controlled so that the above-mentioned Zn content is within a predetermined range, the insulating film should contain a sufficient amount of Zn to ensure the corrosion resistance of the cut surface regardless of the blending ratio. Become.
• baking conditions As described above, it is necessary to suppress the formation of an oxide layer on the surface of the base steel sheet when the coating liquid is baked. Therefore, in the present invention, it is important to control the baking conditions.
• the baking of the coating liquid is performed by a continuous line.
• the tension applied to the steel sheet is 15 to 60 N / N /. Let it be mm 2.
• the tensile strength is preferably 20 N / mm 2 or more, and preferably 50 N / mm 2 or less.
• the mechanism has not been clarified, but if the tensile strength applied to the steel sheet is too low, the steel sheet may meander and cause contact with equipment in the baking furnace, and the coating liquid is uniform. It is presumed that there will be a part that is easily oxidized because it will not be applied to. On the other hand, even if the tensile strength is excessive, it is considered that the grain boundaries are expanded to facilitate oxidation.
• the oxygen concentration in the atmosphere in the baking furnace is set to 30% or less.
• the oxygen concentration is preferably 20% or less.
• the maximum temperature reached during baking should be within the range of 250 to 450 ° C.
• Example 1 Tension during baking Before forming the composite film, an annealed non-oriented electrical steel sheet (that is, a base steel sheet) having a thickness of 0.5 mm was prepared. Since the annealing was performed in a low oxidizing atmosphere, the surfaces of these base steel sheets were not oxidized. 100 g of a phosphate aqueous solution having a solid content concentration of 50% and an acrylic / styrene resin having a concentration of 40%, wherein the Zn molar ratio was adjusted to 20% with a mixture of Al phosphate and Zn phosphate with respect to this base steel plate. A mixed solution with 20 g of an aqueous dispersion was applied. Then, the atmospheric oxygen concentration was set to 20%, the maximum temperature reached was set to 340 ° C., and a composite film was formed while applying various tensions.
• the amount of the composite film was set to 1.5 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides. Then, the Zn content per one side of the composite film was determined by the above-mentioned "dissolution in bromine / methanol solution-acid / alkali melting preparation-ICP analysis method". As a result, the Zn content of each of the composite films was 10 mg / m 2 per side.
• the non-oriented electrical steel sheet having the composite film was cut to a size of 20 mm ⁇ 50 mm with a shearing machine. Twenty pieces of non-oriented electrical steel sheets that had been cut were laminated so that the total height of the cut surfaces was about 10 mm. Corrosion resistance was evaluated by a salt spray method on one 10 mm ⁇ 50 mm cut laminated surface of this laminated body.
• the salt spray method corrosion resistance test was performed according to "JIS Z 2371".
• the NaCl concentration of the aqueous salt solution for the test was 5% by mass.
• the temperature near the test piece cage in the spray chamber was 35 ° C.
• the quality of corrosion resistance was judged by the red rust area ratio of the cut laminated surface of each non-oriented electrical steel sheet at the time when the spraying time was 8 hours, and the level was classified as follows. The case where the judgment was A or B was regarded as a pass.
• Example 2 Zn content and oxygen concentration
• An annealed non-oriented electrical steel sheet that is, a base steel sheet
• a base steel sheet having a thickness of 0.5 mm was prepared before forming the composite film. Since the annealing was performed in a low oxidizing atmosphere, the surfaces of these base steel sheets were not oxidized.
• the concentration was 100 g of a phosphate aqueous solution having a solid content concentration of 50%, in which the Zn molar ratio was adjusted in the range of 0 to 100% with Al phosphate, Zn phosphate or a mixture thereof.
• a mixture of 15 g of a 40% acrylic-styrene organic resin aqueous dispersion was applied. Then, at various atmospheric oxygen concentrations, the maximum temperature reached was 340 ° C., and a composite film was formed.
• the tensile strength applied to the steel sheet at the time of baking was 22 N / mm 2 .
• the amount of the composite film was set to 1 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides.
• Various analyzes and evaluations were performed according to the same criteria as in Example 1. The results are shown in Tables 2 and 3.
• the Zn content of the composite film is 10 mg / m 2 or more per side, and the product of the oxygen content and the plate thickness of the base steel sheet is 50 ppm ⁇ mm. It can be seen that the salt spray corrosion resistance is good.
• Example 3 Zn / Mg phosphate
• an annealed non-oriented electrical steel sheet that is, a base steel sheet having a thickness of 0.5 mm was prepared. Since the annealing was performed in a low oxidizing atmosphere, the surfaces of these base steel sheets were not oxidized.
• the Zn molar ratio was adjusted in the range of 0 to 100% with Mg phosphate, Zn phosphate or a mixture thereof, and 100 g of a phosphate aqueous solution having a solid content concentration of 50% and a concentration of 40. A mixture of 10 g of an aqueous dispersion of an acrylic-styrene organic resin solution was applied. Then, a composite film was formed by setting the atmospheric oxygen concentration to 20% and the maximum temperature reached to 340 ° C.
• the tensile strength applied to the steel sheet at the time of baking was 22 N / mm 2 .
• the amount of the composite film was set to 1 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides.
• Various analyzes and evaluations were performed according to the same criteria as in Example 1. The results are shown in Table 4.
• the metal component of the phosphate is It can be seen that even in the case of Zn / Mg, the salt spray corrosion resistance on the cut surface of the steel sheet is good.
• Example 4 Zn / Ca phosphate
• an annealed non-oriented electrical steel sheet that is, a base steel sheet
• the concentration was 100 g of a phosphate aqueous solution having a solid content concentration of 50%, in which the Zn molar ratio was adjusted in the range of 0 to 100% with Ca phosphate, Zn phosphate, or a mixture thereof.
• a mixture of 20 g of a 40% acrylic-styrene organic resin aqueous dispersion was applied. Then, a composite film was formed by setting the atmospheric oxygen concentration to 30% and the maximum temperature reached to 340 ° C.
• the tensile strength applied to the steel sheet at the time of baking was 22 N / mm 2 .
• the amount of the composite film was set to 1 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides.
• Various analyzes and evaluations were performed according to the same criteria as in Example 1. The results are shown in Table 5.
• the metal component of the phosphate is It can be seen that the salt spray corrosion resistance on the cut surface of the steel sheet is good even if the zinc / Ca type is used.
• Example 5 An annealed non-oriented electrical steel sheet (that is, a base steel sheet) having a thickness of 0.5 mm was prepared before forming the organic resin composite film. Since the annealing was performed in a low oxidizing atmosphere, the surfaces of these base steel sheets were not oxidized. 100 g of a phosphate aqueous solution having a solid content concentration of 50% and a phosphate aqueous solution having a solid content concentration of 50%, in which the Zn molar ratio is adjusted to 70% with a mixture of Al phosphate and Zn phosphate with respect to these base steel sheets, and different types having a concentration of 40% A mixed solution with 15 g of an organic resin aqueous dispersion was applied. Then, a composite film was formed by setting the atmospheric oxygen concentration to 5% and the maximum temperature reached to 340 ° C.
• the tensile strength applied to the steel sheet at the time of baking was 22 N / mm 2 .
• the amount of the composite film was set to 0.8 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides.
• Various analyzes and evaluations were performed according to the same criteria as in Example 1. The results are shown in Table 6.
• the Zn content per side of the composite film was 15 mg / m 2 .
• Example 6 Baking temperature Before forming the composite film, an annealed non-oriented electrical steel sheet (that is, a base steel sheet) having a thickness of 0.5 mm was prepared. Since the annealing was performed in a low oxidizing atmosphere, the surfaces of these base steel sheets were not oxidized. 100 g of a phosphate aqueous solution having a solid content concentration of 50% and an acrylic / styrene resin having a concentration of 40%, wherein the Zn molar ratio was adjusted to 20% with a mixture of Al phosphate and Zn phosphate with respect to this base steel plate. A mixed solution with 20 g of an aqueous dispersion was applied. Then, the composite film was formed at various maximum temperatures with the atmospheric oxygen concentration of 1%.
• the tensile strength applied to the steel sheet at the time of baking was 22 N / mm 2 .
• the amount of the composite film was set to 1.5 g / m 2 per side. Further, the composite film was provided on both sides of the base steel sheet, and the amount and composition of the composite film were substantially the same on both sides.
• Various analyzes and evaluations were performed according to the same criteria as in Example 1. The results are shown in Table 7.
• the Zn content of the composite film was 10 mg / m 2 per side.
• the composite film prepared under the condition that the maximum temperature reached was 200 ° C. was not sufficiently baked onto the base steel sheet and became sticky, and the corrosion resistance of the cut surface could not be evaluated.
• the maximum temperature reached was 510 ° C.
• the rust area ratio was 35% and the corrosion resistance was poor due to the formation of the oxide layer.
• the excellent corrosion resistance of Zn can be obtained even on the cut surface of a steel sheet without using an environmentally hazardous substance such as a chromate-based compound and an expensive organic compound represented by a carboxylic acid-based compound as a coating material. It is possible to manufacture non-directional electromagnetic steel sheets that can be exhibited. Therefore, the non-oriented electrical steel sheet according to the present invention can suppress the occurrence of red rust on the cut surface of the steel sheet even when exposed to a harsh environment such as flying marine salt.

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