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WO1998030729A1 - Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production - Google Patents

Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production Download PDF

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Publication number
WO1998030729A1
WO1998030729A1 PCT/JP1997/000045 JP9700045W WO9830729A1 WO 1998030729 A1 WO1998030729 A1 WO 1998030729A1 JP 9700045 W JP9700045 W JP 9700045W WO 9830729 A1 WO9830729 A1 WO 9830729A1
Authority
WO
WIPO (PCT)
Prior art keywords
steel sheet
hot
plating
dip galvanized
galvanized steel
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP1997/000045
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English (en)
Japanese (ja)
Inventor
Nobue Fujibayashi
Kazuaki Kyono
Motonori Miyaoka
Nobuo Totsuka
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
Kawasaki Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Kawasaki Steel Corp filed Critical Kawasaki Steel Corp
Priority to KR1019970706334A priority Critical patent/KR100325755B1/ko
Priority to EP97900126A priority patent/EP0900857B1/fr
Priority to PCT/JP1997/000045 priority patent/WO1998030729A1/fr
Priority to DE69728389T priority patent/DE69728389T2/de
Priority to US08/913,314 priority patent/US6030714A/en
Priority to CA002215110A priority patent/CA2215110C/fr
Publication of WO1998030729A1 publication Critical patent/WO1998030729A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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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
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • 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
    • B05D3/002—Pretreatement
    • 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
    • B05D3/007—After-treatment
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C18/00—Alloys based on zinc
    • 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
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
    • C23C2/0224—Two or more thermal pretreatments
    • 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
    • C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
    • C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
    • 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
    • C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
    • C23C2/36—Elongated material
    • C23C2/40—Plates; Strips
    • 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/08—Iron or steel
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling

Definitions

  • the present invention relates to a hot-dip galvanized steel sheet having few non-plating defects and excellent adhesion and a method for producing the same.
  • Hot-dip zinc-coated steel sheets are mainly used for automobile bodies because they are inexpensive and have excellent corrosion resistance.However, in addition to corrosion resistance due to plating, the adhesion of plating during press working is required as the performance of steel sheets for automobile bodies. Have been. If the adhesion of the plating deteriorates, the plating layer peels off in powder or lump form, causing mold seizure, deteriorating the corrosion resistance of the peeled part, and causing scratches due to the peeled plating pieces. Was.
  • Japanese Patent Application Laid-Open No. 61-269691 discloses that Fe and Zn are applied at a high temperature of 700 to 850 ° C after hot-dip galvanizing. Need to be alloyed. However, alloying at high temperatures not only increases costs, but also increases the burden on equipment such as rolls.
  • steel contains at least one of Zr, La, Ce, Y, and Ca, and is cooled from recrystallization annealing to plating.
  • the speed is specified at 50 ° CZ seconds or more. Addition of Zr and the like to steel increased costs, and the productivity was poor because the speed of passing through had to be reduced due to the problem of cooling capacity.
  • the components of steel in 0, Al, and N are respectively 0.0045 wt% or less, and (25 XN wt%) to 0.15 wt%. , 0.03 It is specified as 0 wt% or less.
  • the content of Ti, Si, and P in steel is limited and the content of Si (wt%) + P (wt%) ⁇ Ti (wt%) is satisfied.
  • the regulation by the component does not always achieve the steel sheet performance such as the desired strength and drawability, and the adhesion from the specified component range may be reduced due to the deviation from the specified component range.
  • recrystallization annealing In applying such hot-dip galvanizing to a steel sheet, recrystallization annealing must be performed at a high temperature of about 700 to 900 ° C. in order to obtain excellent material properties.
  • CGL recrystallization annealing is performed in a nitrogen atmosphere in the presence of hydrogen (referred to as reduction annealing).
  • reduction annealing this atmosphere is a reducing atmosphere for Fe, it is not suitable for elements such as SiMn and P. It is an oxidizing atmosphere. Therefore, elements that are more easily oxidized than Fe (such as Si, Mn, and P) during the reduction annealing (called oxidizable elements) diffuse out and combine with oxygen on the steel sheet surface to form oxides ( This is called surface thickening).
  • Japanese Patent Publication No. Sho 61-93386 proposes a method of pre-plating Ni on the surface of a steel sheet prior to hot-dip galvanizing. ing.
  • S i 0.2 to 2 ⁇ Ow t%
  • Mn 0.5 to 2.0 w t%
  • C r 0.1 to 20 w t% when intended for the steel containing more than one kind
  • the adhesion amount is required to be subjected to 1 O gZm 2 or more N i plating had invited an increase in cost.
  • hot-dip galvanizing and the wettability of the steel sheet are improved, but defects caused by Si and Ni on the plating surface during the alloying process. There was a problem of frequent occurrence.
  • Japanese Patent Application Laid-Open No. 57-70268 proposes a method of pre-plating Fe on the surface of a steel sheet prior to hot-dip galvanizing. According to this method, it is possible to prevent non-plating defects of the Si-added steel by pre-plating, but this requires the application of Fe plating of 5 gZm 2 or more, which is extremely uneconomical. Was.
  • the Fe oxide film will be peeled off by a roll, etc., and instead the surface will thicken, impairing the plating property, and the peeled Fe oxide film will be scattered in the furnace. And adversely affect the operation.
  • hot-dip galvanizing of high-strength steel sheets a known proposal regarding the composition of the steel and the conditions of hot rolling (also abbreviated as hot rolling) is disclosed in Disclosure of methods for winding steel containing S i ⁇ 0.2 and Mn ⁇ 1.5 at a temperature of 650 ° C or higher, followed by pickling, cold rolling, annealing and hot-dip galvanizing According to Japanese Patent Application Laid-Open No. 6-179943, steel containing Si: 0 ⁇ 10 ⁇ to 1.5 wt% and Mn: l. It discloses a method of winding and pickling at a temperature of 80 or less, followed by cold rolling annealing and hot-dip galvanizing.
  • the present invention provides a hot-dip galvanized steel sheet having an oxide of an element that is more easily oxidized than iron, immediately below the plating layer.
  • the oxygen concentration in a range of 3 ⁇ m in the thickness direction from the surface layer of the base steel sheet below the plating layer is preferably 1 ppm or more, and more preferably 2 ppm.
  • 200200 ppm is preferred, and 3 to 100 ppm is more preferred.
  • these hot-dip galvanized steel sheets are further subjected to a heat-alloying treatment after being subjected to the zinc plating, whereby an excellent alloyed hot-dip galvanized steel sheet is provided.
  • the oxygen concentration in a range of 3 m from the surface layer of the base steel sheet below the plated layer in the thickness direction is preferably 1 ppm or more. Preferably, it is 2 to 200 ppm, more preferably 3 to 100 ppm.
  • any of the above-mentioned hot-dip galvanized steel sheets or alloyed hot-dip galvanized steel sheets at least one selected from the group consisting of Si, Mn and P is used as the steel sheet component. 0.00 1 ⁇ S i ⁇ 3.0w t% ⁇
  • the present invention also provides a method for producing a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet having few non-plating defects and excellent plating adhesion.
  • Process A When the hot-rolled steel strip is wound into a coil, the temperature of the steel strip
  • Process B Process of applying molten zinc plating
  • step B is provided after step A, and another processing step may be provided between step A and step B.
  • another processing step may be provided between step A and step B.
  • an acid pickling step, a degreasing step, a cold rolling step, an annealing step and the like are appropriately used.
  • the oxide formed in the step A is left in a pretreatment step performed after the step A and before an annealing furnace treatment immediately before the step B.
  • At least one slab to be subjected to the hot rolling is selected from the group consisting of Si, Mn and P as components.
  • the heat alloying treatment is performed.
  • This oxide is generated during hot rolling, and can be grown and formed particularly when the temperature during coil winding (abbreviated as CT) is high and the cooling rate is low thereafter.
  • CT temperature during coil winding
  • Fig. 1 shows the results of the analysis of the acid sardines found at the hot-rolled B temple using an electron probe microanalyzer (abbreviated as EPMA). Peaks are observed in Mn, P, A, and O, indicating that these oxides are formed.
  • the components in the steel are Mn: 0.1 wt%, P: 0.06 wt%, A1: 0.03 wt%, especially Mn, P, A 1 is not a steel sheet with a large amount.
  • the oxide immediately below the plating layer is the oxide immediately below the scale formed in the hot-rolling stage, and the subsequent treatment step such as pickling and plating. Are left even after passing through.
  • the mechanism by which oxides are formed immediately below the scale is that the oxygen in the scale layer mainly composed of iron oxide generated during hot rolling diffuses inside the steel after winding the steel strip, and then diffuses into the steel. To form an oxide of an easily oxidizable element. Therefore, it is formed even if the content of steel is very small.
  • an oxide of an element that is more easily oxidized than iron exists immediately below the molten zinc-based plating, but other oxides of an element that are less easily oxidized than iron oxide or iron Oxides may be included. In the present invention, it is more preferable that this oxide is formed at the crystal grain boundary of the hot-rolled sheet.
  • the present inventors have studied and prepared various steel sheets. As a result, as oxides, si—O system, Mn—O system, Al—O system, P—O system, and Fe—S including Fe i — O-based oxides are detected.
  • Fig. 2 shows a conventional steel sheet
  • Fig. 3 shows a Glow dis charge spectroscopy (abbreviated as GDS) in the depth direction from the surface layer of the unannealed sheet after cold rolling where oxides are observed to about 10 m. 2) shows the results of elemental analysis measurement by.
  • the peaks of Mn, Al, P, and O appearing at a depth of about 0.3 to 4 ⁇ t m from the surface layer in FIG. 3 correspond to oxides.
  • Fig. 4 shows the results of a conventional steel sheet
  • Fig. 5 shows the results of elemental analysis by GDS in the depth direction from the surface layer after cold rolling annealing to about 10 / im where oxides are observed.
  • a large amount of surface condensate generated by reduction annealing is observed, while in the steel sheet with oxide generated during hot rolling, as shown in Fig. 5, Production is suppressed and hardly observed.
  • the oxide present on the surface layer of the steel sheet immediately below the plating layer can be observed with an optical microscope by etching with 1% nital solution for several seconds to several tens of seconds. .
  • FIGS. 8 and 9 are cross-sectional optical micrographs of the alloyed hot-dip galvanized steel sheet at a magnification of 1000.
  • the black strips (indicated by-) observed immediately below the plating layer are oxides.
  • Oxide formation can also be confirmed by performing oxygen analysis in steel.
  • the method used is to remove the scale layer by pickling after hot-rolling, remove the scale layer of hot-dip galvanized steel sheet, or use a cold-rolled unannealed or annealed sheet. It is sufficient to compare the analysis value of oxygen in steel in the direction with the analysis value of oxygen in steel of a steel sheet from which the surface layer where oxide is formed is removed by grinding or the like. In the case of oxide-producing steel sheets, the total thickness direction analysis value is larger than the analysis value of the ground plate. Next, the mechanism by which non-plating defects and plating adhesion are improved by forming an oxide directly under the plating layer is discussed.
  • oxide is generated immediately below the scale by internal diffusion of oxygen at the time of coiling and after coiling, thereby making it easier to reduce oxidation in CGL. It was found that the surface concentration of the oxidizing element was suppressed.
  • plating is exfoliated mainly by compressive stress during press working.
  • the plating layer is forcibly dissolved to the iron potential by the galvanostatic method (4% methyl salicylate, 1% salicylic acid, 10% methanol solution of potassium iodide Z, 5 mA / cm 2 ).
  • the results are shown in Figs. 10 and 11 when the steel plate is exposed and the steel plate is exposed and observed by SEM. It can be seen that the roughness of the interface between the plating layer and the steel sheet is clearly greater than that of the conventional oxide-free steel sheet.
  • the technology disclosed in the present invention includes, as a component in steel, at least one component selected from the group consisting of Si, Mn, and P;
  • the lower limits of each element are as follows: Si: 0.001 wt%, Mn: 0.05 wt%, P: preferably 0.05 wt%.
  • the upper limit of each element is set as a preferable range from the viewpoint of saturation of the effect of strengthening and cost.
  • the technology disclosed by the present invention has a sufficient effect on both the non-plating defect and the plating adhesion if a small amount is observed by etching with 1% nital in the cross-section observation of the hot-dip galvanized steel sheet using an optical microscope. It has been seen. Also, in the oxygen analysis in steel,
  • the hot-rolling coiling temperature is not higher than 600 ° C, oxides will not be generated, and the cooling rate to 540 ° C after winding will be reduced.
  • the molten zinc-based plating of the present invention refers to molten zinc containing zinc as a whole, and may be galvanized or galvanized containing Si in zinc as well as the molten zinc plating. Further, Pb, Mg, Mn, etc. may be included. Therefore, the conditions of the zinc bath are not particularly limited.
  • An appropriate iron content in the bed is 8 to 13 wt ° / o.
  • the hot rolled sheet and the cold rolled sheet may be used as the original plate for plating.
  • FIG. 2 is a graph of a depth direction elemental analysis of a conventional cold-rolled unannealed sheet from the surface layer to about 10 ⁇ m by GDS.
  • FIG. 4 is a graph of a depth direction elemental analysis of about 10 ⁇ m from the surface layer by GDS after conventional cold rolling annealing.
  • FIG. 5 is a graph of the results of elemental analysis in the depth direction from the surface layer to about 10 ⁇ m by GDS after cold rolling annealing in the example.
  • FIG. 6 is a cross-sectional optical micrograph of the oxide immediately below the scale of the hot-rolled sheet of Example at a magnification of 1000 times.
  • FIG. 7 is a cross-sectional optical microscope photograph of a conventional hot-rolled sheet at a magnification of 100 ⁇ just below the scale.
  • FIG. 8 is a cross-sectional optical micrograph of the alloyed hot-dip galvanized steel sheet having an oxide of Example at a magnification of 1000 times.
  • FIG. 9 is a cross-sectional optical microscope photograph of a conventional oxide-free galvannealed steel sheet at a magnification of 1000 ⁇ .
  • FIG. 10 is a 3 ⁇ 1 photograph of a steel sheet in which a plating layer is melted in an example at a magnification of 150 ⁇ .
  • FIG. 11 This is an SEM photograph of a conventional steel sheet in which a plating layer is melted at a magnification of 1500.
  • Electrolytic degreasing Electrolysis for about 10 seconds in 3% NaOH aqueous solution at 60 ° C
  • Brush mouth Brush roll with abrasive grains
  • the hot-rolled sheet and the cold-rolled sheet were both annealed at 800-850 ° C and then hot-dipped at 470 ° C in CGL. In the case of heat alloying, alloying was continued at 480 to 530 ° C for 15 to 30 seconds.
  • the cross section of the hot-rolled sheet with scale was polished and observed with an optical microscope without etching to measure the penetration depth of the oxide.
  • An appropriate magnification of the optical microscope is 1,000 times.
  • the plated plate was visually observed and evaluated.
  • Table 3 shows the results for hot-dip galvanized steel sheets and Table 4 shows the results for galvannealed steel sheets.
  • Example 1 and Example 2 Example of hot-rolled and cold-rolled side without CGL plating Plating During plating Unplated paddle pad Comparative example Sample surface oxide deposited by pretreatment of oxides Iron content Oxide content Defects Test result Steel No.Presence or removal g / m 2 g / m 2 % PP m Rank Comparative example 1 1 No Yes 0.1 40 1 0.5.0 0 1 4 Example 1 2 Yes Yes 0.1 40 1 0.3 1 1 1 1
  • the technology disclosed in the present invention relates to a hot-dip galvanized steel sheet and an alloyed hot-dip galvanized steel sheet having few non-plating defects and excellent plating adhesion, and is suitable mainly for use in a steel sheet for an automobile body.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Coating With Molten Metal (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

L'invention concerne une tôle d'acier galvanisé à chaud pour automobiles, une tôle d'acier allié galvanisé à chaud, et leur procédé de production. Cette tôle d'acier galvanisé présente une quantité réduite de défauts par suite d'un placage défectueux, ainsi que d'excellentes caractéristiques d'adhérence de dépôt par contact, et est caractérisée en ce qu'elle possède des oxydes de métaux plus oxydables que le fer situé au-dessous du placage, ces oxydes étant formés lors du laminage à chaud. Selon le procédé de production, la température d'enroulement lors du laminage à chaud est égale ou supérieure à 600 °C, le refroidissement s'effectue à une vitesse faible, et les oxydes demeurent intacts également dans les étapes ultérieures.
PCT/JP1997/000045 1995-07-13 1997-01-13 Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production Ceased WO1998030729A1 (fr)

Priority Applications (6)

Application Number Priority Date Filing Date Title
KR1019970706334A KR100325755B1 (ko) 1997-01-13 1997-01-13 도금이안된결함이적고코팅밀착성이우수한아연및아연-합금용융도금강판및이의제조방법
EP97900126A EP0900857B1 (fr) 1997-01-13 1997-01-13 Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production
PCT/JP1997/000045 WO1998030729A1 (fr) 1997-01-13 1997-01-13 Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production
DE69728389T DE69728389T2 (de) 1997-01-13 1997-01-13 Heissgetauchtes galvanisiertes stahlblech mit verminderten defekten, entstanden durch fehlbeschichtung, mit hervorragender kontaktbeschichtungshaftung und verfahren zu dessen herstellung
US08/913,314 US6030714A (en) 1995-07-13 1997-01-13 Zinc and zinc-alloy hot-dip-coated steel sheet having decreased bare spots and excellent coating adhesion and a method for manufacturing the same
CA002215110A CA2215110C (fr) 1997-01-13 1997-01-13 Tole d'acier zinguees (zinc et alliage de zinc) par immersion a chaud presentant peu de surfaces denudees et d'excellentes caracteristiques d'adherence du revetement, et methode de fabrication connexe

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP1997/000045 WO1998030729A1 (fr) 1997-01-13 1997-01-13 Tole d'acier galvanise a chaud presentant peu de defauts par suite d'un placage defectueux, ainsi que d'excellentes caracteristiques d'adherence de depot par contact, et son procede de production

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CN1170954C (zh) * 1999-02-25 2004-10-13 川崎制铁株式会社 钢板、热镀钢板和合金化热镀钢板的制备方法
JP4886118B2 (ja) * 2001-04-25 2012-02-29 株式会社神戸製鋼所 溶融亜鉛めっき鋼板
TWI314955B (en) * 2002-03-01 2009-09-21 Hot-dip galvanizing steel sheet and method for manufacturing a coated steel sheet
WO2011081392A2 (fr) 2009-12-29 2011-07-07 주식회사 포스코 Tôle d'acier zingué pour formage à chaud à la presse présentant des caractéristiques de surface exceptionnelles, pièces moulées embouties à chaud à partir de ladite tôle et procédé de production de celle-ci
US11091818B2 (en) 2015-12-23 2021-08-17 Posco High strength cold-rolled steel sheet and hot-dip galvanized steel sheet having excellent hole expansion, ductility and surface treatment properties, and method for manufacturing same
KR102330604B1 (ko) 2019-12-03 2021-11-24 주식회사 포스코 전기저항 점용접부의 피로강도가 우수한 아연도금강판 및 그 제조방법

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JPH07216524A (ja) * 1994-01-25 1995-08-15 Nisshin Steel Co Ltd 高張力熱延鋼板の溶融めっき方法

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JPH0790529A (ja) * 1993-09-24 1995-04-04 Sumitomo Metal Ind Ltd 珪素含有鋼溶融亜鉛めっき鋼板および合金化溶融亜鉛めっき鋼板の製造方法

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Publication number Priority date Publication date Assignee Title
JPH07216524A (ja) * 1994-01-25 1995-08-15 Nisshin Steel Co Ltd 高張力熱延鋼板の溶融めっき方法

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EP0900857B1 (fr) 2004-03-31
EP0900857A4 (fr) 2000-08-02
EP0900857A1 (fr) 1999-03-10
CA2215110C (fr) 2001-08-14
KR100325755B1 (ko) 2002-07-18
CA2215110A1 (fr) 1998-07-13
DE69728389D1 (de) 2004-05-06
DE69728389T2 (de) 2005-02-24
KR19980702926A (ko) 1998-09-05

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