WO2005080635A1 - Sn-zn alloy hot dip plated steel sheet - Google Patents
Sn-zn alloy hot dip plated steel sheet Download PDFInfo
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- WO2005080635A1 WO2005080635A1 PCT/EP2005/002106 EP2005002106W WO2005080635A1 WO 2005080635 A1 WO2005080635 A1 WO 2005080635A1 EP 2005002106 W EP2005002106 W EP 2005002106W WO 2005080635 A1 WO2005080635 A1 WO 2005080635A1
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- WIPO (PCT)
- Prior art keywords
- steel sheet
- flash
- hot dip
- tin
- plated steel
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Classifications
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- 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
-
- 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
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/026—Deposition of sublayers, e.g. adhesion layers or pre-applied alloying elements or corrosion protection
-
- 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
- C23C2/08—Tin 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
- C23C28/021—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material including at least one metal alloy layer
-
- 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
- C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D
- C23C28/02—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material
- C23C28/023—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D only coatings only including layers of metallic material only coatings of metal elements only
Definitions
- This invention relates to a Sn-Zn alloy hot dip plated steel sheet having solderability, corrosion resistance and press formability for example for fuel tanks and a production method thereof.
- a Sn-Zn alloy hot dip plated steel sheet is known for its corrosion resistance and solderability (weldability). Because of the hot dip plating method the deposition quantity of plating is relatively high and the products produced by this method have been used under severe environments such as fuel tanks and for outdoor use.
- the known steel sheet and a method of producing it reference is made to US 5,827,618.
- this prior art product and technology described above are not free from drawbacks. Firstly a careful study of samples of the known plated steel sheet now available in the market has revealed that the sheet does not always perform well regarding corrosion resistance.
- the inventors of the present invention have examined sheet samples in detail and established the relationship between the presence of Sn-rich-dendrites as well as so called outbursts and the corrosion resistance for Sn-Zn hot dip coated steel sheet, as well as between the presence of so called outbursts and the formability of certain types of Sn-Zn hot dip coated steel sheet and have clarified quantitatively the crucial parameters in this respect as well as found a process of manufacturing a Sn-Zn hot dip plated steel sheet satisfying the highest standards.
- the Sn-Zn hot dip coated steel sheet according to the invention is a type of steel substrate that is coated with a Ni flash layer before it is hot dip coated.
- the present inventors have clarified the influence of the presence of Sn-rich-dendrites in the Sn-Zn alloy layer. It has been found that if there are (too many) Sn-rich-dendrites present, the plating layer is likely to be corroded, and useful life till penetration of the plating layer becomes shorter than if the Sn-rich-dendrites are avoided. It is believed that Sn-rich-dendrites increase the risk of deterioration of the Sn-Zn containing eutectical phase caused by the difference in electrochemical potential between the phases in question. After corrosion tests involving contact with a fuel, the fuel was shown to contain proportionally significantly more Sn than Zn which substantiates this hypothesis.
- the attack will take place locally caused by the formation of Sn-rich-dendrites from the Sn-Zn coating layer towards the steel substrate. In this way different phases will be present near the surface which may enhance galvanic corrosion. Further the relation between the presence of so called outbursts extending from the Ni flash layer to the surface of the Sn-Zn alloy layer has been clarified. It has been found that if there are (too many) outbursts present, the steel sheet is likely to perform sub optimal regarding formability and also corrosion resistance. Outbursts reaching the Sn-Zn surface form Fe-Zn rich craters which are more susceptible to corrosion. The Ni flash is important as a wetting agent.
- Ni flash is applied by electroplating and the substrate is thoroughly rinsed thereafter, preferably using a water rinse.
- the Ni flash greatly transforms into NiZn. This explains why the hot dip bath must be supplied with additional Zn and why the Zn concentration in the resulting Sn- Zn hot dip plating layer is higher than in the hot dip bath. Further, the present inventors have found a method for producing the Sn-Zn alloy plating layer described above.
- the process to manufacture a Sn-Zn alloy plated steel sheet according to the invention comprises the steps of degreasing and pickling an annealed steel sheet into a bath comprising 8,5 to 9,5 wt % of Zn, preferably 8,8 to 9,2 % of Zn and the balance tin and unavoidable impurities among which Pb less than 0,1 wt % at conventional bath temperatures which depend on the entry temperature of the steel substrate.
- the deposition quantity is adjusted and the material is cooled at normal cooling rates typically of 10 °C/s or more.
- FIG. 1 shows in the form of a back scattered electron image, the presence of Sn-rich-dendrites indicated by "Tin dendrites" in the Sn-Zn layer of a Sn-Zn alloy plated steel sheet, which "Tin dendrites" should be avoided according to the invention.
- Fig. 2 shows a Sn-rich-dendrite indicated by “Sn “rich” dendrite” and Sn-Zn eutectic material indicated as “SnZn eutectic”.
- Fig. 3 shows an outburst indicated as "FeZn rich crater at SnZn surface caused by outburst".
- Fig. 1 also remains of a surface treatment are indicated as "Remaining surface treatment”.
- the present invention has clarified the relationship between the presence of Sn-rich-dendrites and outbursts respectively and corrosion and formability.
- An annealed steel sheet obtained by conducting heat-treatment and rolling such as hot rolling, pickling, cold rolling, etc., or a rolled material, is used as a raw sheet for plating, and after pre-treatment such as the removal of a rolling oil, etc., plating is carried out.
- the Ni flash on the steel substrate this is preferably applied by electroplating.
- the thickness of the Ni flash is preferably 0, 15 ⁇ m or below.
- the hot dip bath contains 8,5 wt % ⁇ Zn ⁇ 9,5 wt %, preferably 8,8 wt % ⁇ Zn ⁇ 9,2 wt %.
- Zn content of the Sn-Zn layer is too low due to the zinc concentration in the hot dip bath being too low, on the surface of the resulting samples fine tin dendrites could be seen.
- the nickel flash is useful for the coating to achieve good wetting of the substrate surface and to reduce outburst formation. It is desirable according to the invention that the amount of Sn-rich-dendrites is below 5 % when determined at the surface according to the method described hereafter.
- Tin dendrites can be clearly detected at the surface using SEM or Microprobe elemental mapping techniques (respectively EDX or WDX) at a magnitude of 800 to 1600.
- the tin dendrites, having a typical feather-like structure clearly show another phase coloring (lighter) in the EDX/WDX elemental maps than the eutectic tin-zinc phase lying in between the tin rich dendrite feathers.
- the tin dendrites can be quantified as area tin dendrites/total area with the Microprobe technique by using the difference in local Zn intensity.
- the relevant area preferably is ⁇ 5 % of the total sample area.
- Method to quantify outbursts The amount of outbursts can be detected by using the same techniques as mentioned above.
- the FeZn(Ni) rich outbursts reaching this tin zinc surface form pores, which will show another coloring than the surrounding eutectic tin zinc surface (see Fig. 3).
- the pores can be detected by using the difference in local Fe (or Sn) intensity.
- the relevant area preferably is ⁇ 5% of the total sample area.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Coating With Molten Metal (AREA)
Abstract
The invention relates to a steel sheet having a Ni flash coated onto it, and subsequently a Sn-Zn alloy plating layer obtained by hot dipping the Ni flash coated steel sheet in a molten bath characterized in that the bath contains 8,5 wt % ≤ Zn ≤ 9,5 wt % and the balance tin and unavoidable impurities among which Pb < 0,1 wt %.
Description
Sn-Zn alloy hot dip plated steel sheet
This invention relates to a Sn-Zn alloy hot dip plated steel sheet having solderability, corrosion resistance and press formability for example for fuel tanks and a production method thereof. A Sn-Zn alloy hot dip plated steel sheet is known for its corrosion resistance and solderability (weldability). Because of the hot dip plating method the deposition quantity of plating is relatively high and the products produced by this method have been used under severe environments such as fuel tanks and for outdoor use. As to the known steel sheet and a method of producing it reference is made to US 5,827,618. However, this prior art product and technology described above are not free from drawbacks. Firstly a careful study of samples of the known plated steel sheet now available in the market has revealed that the sheet does not always perform well regarding corrosion resistance. Secondly, this study has revealed that a specific category of the sheet in question does not always perform well regarding formability. According to the present invention it has been found that critical criteria in the plating layer of the steel sheet should be observed if the steel sheet is to perform according to the highest standards for hot dip Sn-Zn plated sheet regarding corrosion resistance and formability respectively. According to the present invention also a production method has been found that produces such a Sn-Zn plated sheet that performs according to the highest standards. The inventors of the present invention have examined sheet samples in detail and established the relationship between the presence of Sn-rich-dendrites as well as so called outbursts and the corrosion resistance for Sn-Zn hot dip coated steel sheet, as well as between the presence of so called outbursts and the formability of certain types of Sn-Zn hot dip coated steel sheet and have clarified quantitatively the crucial parameters in this respect as well as found a process of manufacturing a Sn-Zn hot dip plated steel sheet satisfying the highest standards. The Sn-Zn hot dip coated steel sheet according to the invention is a type of steel substrate that is coated with a Ni flash layer before it is hot dip coated.
Particularly, the present inventors have clarified the influence of the presence of Sn-rich-dendrites in the Sn-Zn alloy layer. It has been found that if there are (too many) Sn-rich-dendrites present, the plating layer is likely to be corroded, and useful life till penetration of the plating layer becomes shorter than if the Sn-rich-dendrites are avoided. It is believed that Sn-rich-dendrites increase the risk of deterioration of the Sn-Zn containing eutectical phase caused by the difference in electrochemical potential between the phases in question. After corrosion tests involving contact with a fuel, the fuel was shown to contain proportionally significantly more Sn than Zn which substantiates this hypothesis. The attack will take place locally caused by the formation of Sn-rich-dendrites from the Sn-Zn coating layer towards the steel substrate. In this way different phases will be present near the surface which may enhance galvanic corrosion. Further the relation between the presence of so called outbursts extending from the Ni flash layer to the surface of the Sn-Zn alloy layer has been clarified. It has been found that if there are (too many) outbursts present, the steel sheet is likely to perform sub optimal regarding formability and also corrosion resistance. Outbursts reaching the Sn-Zn surface form Fe-Zn rich craters which are more susceptible to corrosion. The Ni flash is important as a wetting agent. Further, it turns out that outbursts are largely avoided if the Ni flash is applied by electroplating and the substrate is thoroughly rinsed thereafter, preferably using a water rinse. The Ni flash greatly transforms into NiZn. This explains why the hot dip bath must be supplied with additional Zn and why the Zn concentration in the resulting Sn- Zn hot dip plating layer is higher than in the hot dip bath. Further, the present inventors have found a method for producing the Sn-Zn alloy plating layer described above. The process to manufacture a Sn-Zn alloy plated steel sheet according to the invention comprises the steps of degreasing and pickling an annealed steel sheet into a bath comprising 8,5 to 9,5 wt % of Zn, preferably 8,8 to 9,2 % of Zn and the balance tin and unavoidable impurities among which Pb less than 0,1 wt % at conventional bath temperatures which depend on the entry temperature of the steel substrate. The deposition quantity is adjusted and the material is cooled at normal cooling rates typically of 10 °C/s or more.
Reference is also made to the drawings in which Fig. 1 shows in the form of a back scattered electron image, the presence of Sn-rich-dendrites indicated by "Tin dendrites" in the Sn-Zn layer of a Sn-Zn alloy plated steel sheet, which "Tin dendrites" should be avoided according to the invention. Fig. 2 shows a Sn-rich-dendrite indicated by "Sn "rich" dendrite" and Sn-Zn eutectic material indicated as "SnZn eutectic". Fig. 3 shows an outburst indicated as "FeZn rich crater at SnZn surface caused by outburst". In Fig. 1 also remains of a surface treatment are indicated as "Remaining surface treatment". As described above, the present invention has clarified the relationship between the presence of Sn-rich-dendrites and outbursts respectively and corrosion and formability. An annealed steel sheet obtained by conducting heat-treatment and rolling such as hot rolling, pickling, cold rolling, etc., or a rolled material, is used as a raw sheet for plating, and after pre-treatment such as the removal of a rolling oil, etc., plating is carried out. As to the Ni flash on the steel substrate, this is preferably applied by electroplating. The thickness of the Ni flash is preferably 0, 15 μm or below. It is essential that the hot dip bath contains 8,5 wt % ≤ Zn ≤ 9,5 wt %, preferably 8,8 wt % ≤ Zn ≤ 9,2 wt %. When the Zn content of the Sn-Zn layer is too low due to the zinc concentration in the hot dip bath being too low, on the surface of the resulting samples fine tin dendrites could be seen. The nickel flash is useful for the coating to achieve good wetting of the substrate surface and to reduce outburst formation. It is desirable according to the invention that the amount of Sn-rich-dendrites is below 5 % when determined at the surface according to the method described hereafter. In the same way it is desirable according to the invention that the amount of outbursts is below 5 % when determined at the surface according to the method described hereafter. Method to quantify amount of tin dendrites:
Tin dendrites can be clearly detected at the surface using SEM or Microprobe elemental mapping techniques (respectively EDX or WDX) at a magnitude of 800 to 1600. The tin dendrites, having a typical feather-like structure (see Fig. 1 and Fig. 2) clearly show another phase coloring (lighter) in the EDX/WDX elemental maps than the eutectic tin-zinc phase lying in between the tin rich dendrite feathers. The tin dendrites can be quantified as area tin dendrites/total area with the Microprobe technique by using the difference in local Zn intensity. The relevant area preferably is < 5 % of the total sample area. Method to quantify outbursts: The amount of outbursts can be detected by using the same techniques as mentioned above. At the tin zinc surface, the FeZn(Ni) rich outbursts reaching this tin zinc surface form pores, which will show another coloring than the surrounding eutectic tin zinc surface (see Fig. 3). The pores can be detected by using the difference in local Fe (or Sn) intensity. The relevant area preferably is < 5% of the total sample area.
Claims
1. A steel sheet having a Ni flash coated onto it, and subsequently a Sn-Zn alloy plating layer obtained by hot dipping the Ni flash coated steel sheet in a molten metal bath characterized in that the bath contains 8,5 wt % < Zn < 9,5 wt % and the balance tin and unavoidable impurities among which Pb < 0,1 wt %.
2. A steel sheet according to claim 1 , characterized in that the bath contains 8,8 wt % ≤ Zn ≤ 9,2 wt %.
3. A steel sheet according to claim 1 or claim 2, characterized in that the thickness of the Ni flash layer is 0,15 μm or less.
4. Process for producing Sn-Zn coated steel sheet for corrosion critical applications, comprising the steps of: applying a Ni flash onto a steel substrate; applying a flux; immersing said steel sheet in a bath consisting of 8,5 to 9,5 wt %, preferably of 8,8 to 9,2 wt % of zinc and the balance of tin and unavoidable impurities; cooling said plated steel sheet.
5. Process according to claim 4, characterized in that the plated steel sheet is cooled at a cooling rate of 10 °C/s or more.
6. Process according to claim 4 or claim 5, wherein the Ni flash is applied by electroplating.
7. Process according to any of claims 4 - 6, characterized in that the steel sheet is water-rinsed thoroughly after application of the Ni flash.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0618785A GB2426766B (en) | 2004-02-25 | 2005-02-25 | Sn-zn alloy hot dip plated steel sheet |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP04075592.8 | 2004-02-25 | ||
| EP04075592 | 2004-02-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2005080635A1 true WO2005080635A1 (en) | 2005-09-01 |
Family
ID=34878267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP2005/002106 WO2005080635A1 (en) | 2004-02-25 | 2005-02-25 | Sn-zn alloy hot dip plated steel sheet |
Country Status (3)
| Country | Link |
|---|---|
| GB (1) | GB2426766B (en) |
| WO (1) | WO2005080635A1 (en) |
| ZA (1) | ZA200607991B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1905859A1 (en) * | 2005-07-05 | 2008-04-02 | Nippon Steel Corporation | HOT-DIP Sn-Zn SYSTEM COATED STEEL SHEET HAVING GOOD CORROSION RESISTANCE |
| CN111989419A (en) * | 2018-04-26 | 2020-11-24 | 日本制铁株式会社 | Hot-dip Sn-Zn alloy-plated steel sheet and method for producing same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5837165A (en) * | 1981-08-31 | 1983-03-04 | Nippon Steel Corp | Excellent corrosion resistance and high temperature durability molten Al alloy plated steel sheet with plated appearance and its manufacturing method |
| GB2289691A (en) * | 1994-03-14 | 1995-11-29 | Berkman Louis Co | Coated metal |
| WO1996030560A1 (en) * | 1995-03-28 | 1996-10-03 | Nippon Steel Corporation | Rust-preventive steel sheet for fuel tank and process for producing the sheet |
| JP2002332556A (en) * | 2001-05-14 | 2002-11-22 | Nippon Steel Corp | Method for producing hot-dip Sn-Zn plated steel sheet |
-
2005
- 2005-02-25 ZA ZA200607991A patent/ZA200607991B/en unknown
- 2005-02-25 GB GB0618785A patent/GB2426766B/en not_active Expired - Fee Related
- 2005-02-25 WO PCT/EP2005/002106 patent/WO2005080635A1/en active Application Filing
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5837165A (en) * | 1981-08-31 | 1983-03-04 | Nippon Steel Corp | Excellent corrosion resistance and high temperature durability molten Al alloy plated steel sheet with plated appearance and its manufacturing method |
| GB2289691A (en) * | 1994-03-14 | 1995-11-29 | Berkman Louis Co | Coated metal |
| WO1996030560A1 (en) * | 1995-03-28 | 1996-10-03 | Nippon Steel Corporation | Rust-preventive steel sheet for fuel tank and process for producing the sheet |
| EP0763608A1 (en) * | 1995-03-28 | 1997-03-19 | Nippon Steel Corporation | Rust-preventive steel sheet for fuel tank and process for producing the sheet |
| JP2002332556A (en) * | 2001-05-14 | 2002-11-22 | Nippon Steel Corp | Method for producing hot-dip Sn-Zn plated steel sheet |
Non-Patent Citations (2)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 007, no. 118 (C - 167) 21 May 1983 (1983-05-21) * |
| PATENT ABSTRACTS OF JAPAN vol. 2003, no. 03 5 May 2003 (2003-05-05) * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1905859A1 (en) * | 2005-07-05 | 2008-04-02 | Nippon Steel Corporation | HOT-DIP Sn-Zn SYSTEM COATED STEEL SHEET HAVING GOOD CORROSION RESISTANCE |
| EP1905859A4 (en) * | 2005-07-05 | 2010-02-24 | Nippon Steel Corp | COATED STEEL SHEET WITH SN-ZN HOT IMMERSION SYSTEM HAVING GOOD RESISTANCE TO CORROSION |
| US7981463B2 (en) | 2005-07-05 | 2011-07-19 | Nippon Steel Corporation | Hot-dip Sn-Zn coated steel sheet having excellent corrosion resistance |
| CN111989419A (en) * | 2018-04-26 | 2020-11-24 | 日本制铁株式会社 | Hot-dip Sn-Zn alloy-plated steel sheet and method for producing same |
Also Published As
| Publication number | Publication date |
|---|---|
| ZA200607991B (en) | 2008-06-25 |
| GB0618785D0 (en) | 2006-11-01 |
| GB2426766B (en) | 2007-08-29 |
| GB2426766A (en) | 2006-12-06 |
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