Classifications

• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
  • C23C2/06—Zinc or cadmium or alloys based thereon
• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
  • C23C2/16—Removing excess of molten coatings; Controlling or regulating the coating thickness using fluids under pressure, e.g. air knives
  • C23C2/18—Removing excess of molten coatings from elongated material
• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/26—After-treatment
• • 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
  • C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
  • C23C2/26—After-treatment
  • C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
  • C23C2/29—Cooling or quenching
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12785—Group IIB metal-base component
  • Y10T428/12792—Zn-base component
  • Y10T428/12799—Next to Fe-base component [e.g., galvanized]

Definitions

• the present invention relates to a hot-dip galvanized steel sheet, and more particularly, to a hot-dip galvanized steel sheet having excellent bonding brittleness even at cryogenic temperatures and excellent deep workability and a method of manufacturing the same.
• galvanized steel sheet is produced by passing the steel sheet through a hot dip galvanizing bath and uncoiling the hot dip zinc coated on the steel sheet.
• coarse grains called spangles of dendritic shape are formed on the surface of the molten zinc plated layer.
• the sparkle is formed due to the uneven reaction properties of zinc.
• the branched dendrite grows very rapidly at the beginning of coagulation nuclei to form a skeleton of the plated structure, and then unglazed molten zinc remained between the dendrites.
• the pool is unfinished and the unfinished reaction ends, thereby forming a sparkle.
• the size of the glazing may be said to depend on the size of the skeleton of the plating structure determined in the early stages of zinc. Due to the spangles, the adhesion of the paint to the surface of the plating layer and the corrosion resistance of the steel sheet are poor, and surface irregularities caused by the glaze are not removed even after coating, and the glaze is visible through the paint, so that the surface appearance of the steel sheet is poor. Therefore, in order to minimize the size of the spangles formed on the hot-dip galvanized steel sheet, a solution of the inorganic salt is sprayed after the hot-dip zinc is attached to the steel sheet before being uncoated. At this time, the solution is sprayed toward the steel sheet through the electrode provided on the front of the nozzle.
• a phosphate solution is generally used as the solution of the inorganic salt. Through the injection of the micronized phosphate solution by the electrostatic sparkling size is
• a plating structure of 150 or less can be obtained.
• the steel sheet finely polished to 150 // m or less has a beautiful surface appearance, and is excellent in terms of clarity, corrosion resistance, and dropping of the coating layer powder during continuous pressing after coating.
• the glazing shows different appearance depending on how the hexagonal crystal structure of zinc is formed on the surface of the steel sheet. This means that the hexagonal crystal structure of zinc is placed at different angles for each plating layer.
• the hot-dip galvanized steel sheet having a glazing of 150 or less and the hot-dip galvanizing steel having the glazing of 400 jMn or more are shown in FIGS. 1A and 1B, respectively.
• a general hot-dip galvanized steel sheet having a glazing angle of 400; m or more is advantageous for brittleness because of large zinc crystals and random orientation, but has a problem of poor surface appearance.
• the spangle has the same crystal orientation and its direction is zinc basic The (0001) plane, which is a plane plane, lies parallel to the steel plate surface.
• the crystal orientation in which the basic plane of zinc lies parallel to the surface of the steel sheet is known to have the best corrosion resistance, corrosion resistance, and chemical stability. Accordingly, many developments have been made to improve these properties until recently.
• Japanese Patent Laid-Open Publication No. 1999-100653 discloses a technology for controlling the spangle size to 60-1000 ⁇ by mist spraying using a nozzle, and Japanese Patent Laid-Open Publication No.
• the structural adhesive In the case of using the structural adhesive, it is necessary to check the adhesion between the plated steel sheet at a cryogenic temperature of -40 ° C in consideration of the use of automobiles in cold polar regions, unlike the mechanical welding method of spot welding.
• the adhesive is used on a non-spangle steel plate in which the (0001) side of zinc is placed parallel to the steel plate surface, the plated layer may be deep processed or the plated layer / ferrous iron interface may be peeled off at -40 ° C cryogenic temperatures. There is a problem that causes the phenomenon.
• One aspect of the present invention is to provide a hot-dip galvanized steel sheet having excellent deep workability and cryogenic bond brittleness and a method for manufacturing the same by controlling the hot-dip galvanized layer structure and crystal grain size.
• the average diameter of the hot-dip galvanized layer crystal grains of the hot-dip galvanized steel sheet is 150-400 / m, and the preferred orientation concentration on the (0001) plane of the hot-dip galvanized layer is 3000 to 20000 cps (counter per second). And it provides a hot dip galvanized steel sheet excellent in cryogenic bonding brittleness.
• the present invention provides a hot-dip galvanized steel sheet manufacturing method comprising a hot-dip zinc deposition step, hot-dip zinc deposition amount control step, aqueous solution injection step, engraving angle step and temper rolling.
• the aqueous solution spraying step provides a method for producing a hot-dip galvanized steel sheet excellent in deep workability and cryogenic bond brittleness performed by electrospraying demineralized pure water (Demi-Water).
• the size variation of the crystal grains in the hot dip galvanized layer is reduced due to the electrospray of demineralized pure water and the increase in the reduction rate during the temper rolling, and the crystal orientation to the (0001) plane of the zinc crystal is reduced and the plated twin structure Hot-dip galvanized steel sheet with increased fraction is produced.
• a hot-dip galvanized steel sheet excellent in deep processing such as bending processing and joint brittleness at cryogenic temperatures can be obtained.
• (A) is a schematic diagram showing the crystallographic structure of a hot-dip galvanized steel sheet having a sparkle of 150 / / m or less
• (b) is a hot-dip galvanized steel sheet with a spangle of more than 00 m .
• Figure 2 (a) is a hot-dip galvanized steel sheet with a spangle of 150zm or less using X-ray, (b) is a graph showing the measurement results of (0001) plane crystal orientation of a typical hot-dip galvanized steel sheet with a sparkle of 400 or more to be.
• 3 (a) and 3 (b) are photographs showing the cryogenic bond brittle evaluation results of Comparative Example 1 and Inventive Example 1, respectively.
• the average diameter of the hot-dip galvanized layer crystal grains of the hot-dip galvanized steel sheet of the present invention satisfies 150 to 400 / zm.
• the minimum diameter of the crystal grains is 30; / m, and the diameter deviation of the crystal grains is preferably 40% or less of the average grain diameter.
• the brittleness is higher than that of the surrounding crystal structure, which may act as a starting point of cracks, and cause the plating layer to drop during bending of the hot-dip galvanized steel sheet, thereby decreasing workability.
• the crystal deviation of the hot-dip galvanized layer crystal grains of the hot-dip galvanized steel sheet of the present invention preferably has a uniform sparkle size of 40% or less of the average grain diameter. If the deviation is more than 40% and the size difference of the zinc crystal structure is not uniform, there is a problem that the plating layer does not receive a uniform force during plastic deformation, causing the plating layer to drop off locally, and in order to prevent bonding brittleness.
• the hot-dip galvanized steel sheet of the present invention preferably has a concentration of preferential orientation of 3000 to 20000 cps with respect to the (0001) plane of the hot dip galvanized layer.
• concentration of preferential orientation 3000 to 20000 cps with respect to the (0001) plane of the hot dip galvanized layer.
• Max when the X-ray having the concentration of orientation of 20 KV and the current of 10 mA is preferentially, Max.
• the Intensity base material tilt angle 5 ° of the reference values measured for rotation an le 0 ⁇ 360 ° every 5 ° spacing Average), and satisfies 3000 ⁇ 20000cps (counter per second).
• concentration of the preferential orientation in the present invention is limited to 3000 to 20000 cps is advantageous in the brittle side of the plating layer when the concentration of the preferential orientation on the (0001) surface is less than 3000 cps. It becomes bad.
• the plating layer glazing is refined and the surface appearance is beautiful, but there is a problem of causing deep layer workability and brittleness of the plating layer at cryogenic temperatures.
• the twin structure fraction of the hot dip galvanized layer satisfies 30% or more as the volume fraction of the entire structure.
• the plated twin structure generated by temper rolling acts as an important plastic deformation mechanism of zinc crystals, which are dense hexagonal crystals (HCP), which helps to improve deep workability and brittleness.
• the manufacturing method of the hot-dip galvanized steel sheet of the present invention is a molten zinc adhesion step, molten zinc adhesion amount adjusting step, In the hot-dip galvanized steel sheet manufacturing method comprising an aqueous solution injection step, cooling step and temper rolling step,
• the aqueous solution spraying step is characterized in that it is carried out by electrostatic spraying demineralized pure water (Demi-Water).
• the hot dip galvanizing step of the hot dip galvanized steel sheet manufacturing process of the present invention the hot dip galvanized steel sheet is passed through the zinc plating solution.
• the hot dip zinc deposition step is not particularly limited to apply hot dip galvanized solution and zinc plating conditions of any composition generally applied in the art in order to produce hot dip galvanized steel sheet to the hot dip galvanized on the surface of the steel sheet
• the zinc plating solution may generally be a zinc plating solution containing aluminum (A1), antimony (Sb), and / or lead (Pb), which is not intended to limit the present invention.
• the steel sheet is also not particularly limited and any steel sheet known to be commonly used in hot dip galvanizing may be used. After immersing the steel plate in the galvanizing solution, in the step of adjusting the amount of zinc deposition, the galvanizing solution is air-wiped to remove the plating solution that is excessively attached to the steel plate to adjust the plating amount.
• the plating deposition amount is not particularly limited as appropriate by the person skilled in the art according to the needs, such as the use of the steel sheet in the range generally known in the art.
• deionized pure water (Demi-Water, Demineralized Water) is charged by electrospray during spraying an aqueous solution for unevenness of the hot-dip galvanized layer after adjusting the adhesion amount of the hot-dip zinc to the steel sheet.
• Demineralized pure water in the present invention (Demi- The reason for electrospraying water is to ensure a uniform plating layer structure without variation in size of the glazing. In the case of spraying the solution through charging in order to refine the sparkle, the misted small particles are stratified with the plating layer in the molten state to cause endothermic reaction and promote unevenness.
• the portion where nuclear particles such as phosphate stratifies the plating layer is more endothermic and the surface glare size is smaller, and the portion of the non-fragment is relatively coarse in size.
• a variation in the size of the gloggles will occur. If the size of the spangle is large, the stress cannot be uniformly applied to the plated layer during deep processing, and a small portion of the sparkle can act as a starting point for cracking, and the plated layer is dropped even when bending the hot-dip galvanized steel sheet. It causes the deterioration of workability.
• the demineralized pure water injection pressure of the nozzle is 0.3 to 5.0kgf / cuf, and the air injection pressure is 0.5-7.0kgf / citf, and the pressure / air pressure ratio of the demineralized pure water is 1 It is preferable to perform at / 10-8 / 10. If the pressure of the demineralized pure water is less than 0.3kgf / cuf, there is no effect of miniaturization of the size of the glaze. If the pressure of the demineralized pure water exceeds 5.0kgf / cuf, a solution mark is deposited on the surface of the steel sheet to generate a pitting mark. It is not preferable because the appearance is damaged.
• the size of the charging electrode in front of the nozzle is preferably set to -1 to 25 KV. If the size of the electrode is less than LKV, the electrical attraction does not work, and the effect of miniaturization of the glare from particles is not observed. If the size of the electrode exceeds -25KV, the glare of micronization is excellent and the plating layer is less than 150 / ⁇ Surfaces are obtained resulting in inferior deep workability and cryogenic bond brittleness.
• the electrostatic spraying of the demineralized pure water (Demi-Water) is subjected to skin pass rolling (Skin Pass Mil ling). Twin roughness is formed in the hot dip galvanizing layer by the temper rolling.
• the temper rolling is preferably performed at an elongation of 53 ⁇ 4 or less.
• temper rolling is preferably performed at an elongation of 53 ⁇ 4 or less.
• the twin structure generated during the rough rolling acts as an important processing tool in the zinc crystal, which is a small hexagonal crystal (HCP) with little deformation mechanism.
• HCP hexagonal crystal
• the physical deformation of the temper rolling brings the effect of dispersing zinc preferential orientation to the (0001) plane. Therefore, when temper rolling is not performed, the inferior iron adhesion of the plating layer is inferior to workability and plating adhesion, and when the elongation exceeds 5%, the inferior workability and plating adhesion of the plating layer is excellent, but the inferior iron material is caused. It is not desirable.
• the hot-dip galvanized steel sheet is a soft material IF steel, has a thickness of 0.671 mm 3, and the plating amount is 70 g / m 'at the time of hot-dip galvanizing.
• Table 1 the size and the deviation of the glazing were measured using an optical microscope and the plated layer not subjected to skin pass rolling using an image analyzer. Bond brittleness was measured by the use of Henkel Korea's Sealer Terokal 5089 adhesive for automobile structures at the temperature maintained at -40 ° C.
• O is not foiled, ⁇ is peeled off at 20% or less, and X is peeled off at least 50%.
• the surface appearance and sharpness were measured by visual observation, and O was good, ⁇ : normal, X: bad.
• Comparative Example 1 uses demineralized pure water, but the size of the sparkle of the present invention is satisfactory, but the deviation is too large, and the degree of preferential orientation is out of the range of the present invention, thus showing the inferior brittleness.
• the bonding brittleness was inferior or the surface appearance was deteriorated.
• Comparative Example 6 showing general hot dip galvanizing, the surface appearance was very poor.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Physics & Mathematics (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Thermal Sciences (AREA)
• Coating With Molten Metal (AREA)

Priority Applications (5)

Applications Claiming Priority (1)

Publications (1)

Family

ID=46515890

Family Applications (1)

Country Status (5)

Families Citing this family (5)

Citations (7)

Family Cites Families (6)

• 2011
  • 2011-01-20 CN CN201180069359.9A patent/CN103429781B/zh active Active
  • 2011-01-20 US US13/980,595 patent/US20140017516A1/en not_active Abandoned
  • 2011-01-20 WO PCT/KR2011/000414 patent/WO2012099284A1/ko active Application Filing
  • 2011-01-20 EP EP11856056.4A patent/EP2666882B1/en active Active
  • 2011-01-20 JP JP2013550367A patent/JP5816703B2/ja active Active

Patent Citations (7)

Also Published As

Similar Documents

Legal Events