[go: up one dir, main page]

EP3861146A1 - Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet - Google Patents

Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet

Info

Publication number
EP3861146A1
EP3861146A1 EP18788682.5A EP18788682A EP3861146A1 EP 3861146 A1 EP3861146 A1 EP 3861146A1 EP 18788682 A EP18788682 A EP 18788682A EP 3861146 A1 EP3861146 A1 EP 3861146A1
Authority
EP
European Patent Office
Prior art keywords
less
metal sheet
depth
gas knife
wsa
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.)
Pending
Application number
EP18788682.5A
Other languages
German (de)
French (fr)
Inventor
Edgar Matthijs TOOSE
Henrique DUARTE ALVARENGA
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.)
Tata Steel Ijmuiden BV
Original Assignee
Tata Steel Ijmuiden BV
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 Tata Steel Ijmuiden BV filed Critical Tata Steel Ijmuiden BV
Publication of EP3861146A1 publication Critical patent/EP3861146A1/en
Pending legal-status Critical Current

Links

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
    • C23C2/14—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
    • 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
    • C23C2/003—Apparatus
    • C23C2/0034—Details related to elements immersed in bath
    • C23C2/00342—Moving elements, e.g. pumps or mixers
    • C23C2/00344—Means for moving substrates, e.g. immersed rollers or immersed bearings
    • 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
    • C23C2/20—Strips; Plates
    • 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

Definitions

  • COATED METAL SHEET METHOD TO PROVIDE SUCH A COATED METAL SHEET, AND HOT DIP GALVANIZING DEVICE TO MANUFACTURE SUCH A COATED METAL SHEET
  • the invention relates primarily to a method of providing a coating on a metal sheet, wherein a cold rolled metal sheet is subjected to a hot dip galvanizing operation to provide a metal coating on the metal sheet, which hot dip galvanizing operation comprises guiding the metal sheet through a liquid bath of the metal coating with at least one stabilization roll, wherein each stabilization roll is entirely provided below a predefined depth level below surface level of the liquid bath, and wiping the metal coating that is provided on the metal sheet with at least one gas knife having an outlet to project wiping gas on the metal coating that is provided on the metal sheet that passes along the gas knife.
  • Such a method of providing a coating on a metal sheet is widely known throughout the iron and steel industry; an exemplary publication showing such a method is GB 2517622.
  • a problem also acknowledged in GB 2517622 is the waviness of the coated metal sheet, which causes that after providing the coated metal sheet with a film of paint its outer appearance can be less than optimal.
  • One known problem is the appearance of orange skin which is particularly undesirable for outside body parts of automobiles.
  • GB 2517622 does not particularly provide a workable solution for this problem, for one thing since its disclosure is obscure in relation to the waviness measure it applies.
  • the invention proposes a method to manufacture a coated metal sheet, such a coated metal sheet, a hot dip galvanizing device and its combination with a cold rolling mill in accordance with one or more of the appended claims.
  • Wsa is selected at a value representing a targeted maximum waviness, and values for distance D, height H and Depth are calculated.
  • the method of the invention can suitably be executed by providing that D is 9 mm or less, preferably 8 mm or less, preferably 7 mm or less.
  • the method of the invention can be executed by providing that H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
  • Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
  • Ra is determined in accordance with ISO 4287, using a cut-off of 2.5 mm.
  • Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
  • a coated metal sheet can effectively be provided with a waviness Wsa of 0.41 pm or less, preferably 0.35 pm or less, more preferably 0.31 pm or less, more preferably 0.26 pm or less, most preferably 0.23 pm or less.
  • a suitable minimum value for the targeted maximum waviness Wsa is 0.18 pm.
  • hot dip galvanizing device D is 9 mm or less, preferably 8 mm or less, more preferably 7 mm or less.
  • hot dip galvanizing device H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
  • Preferably Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
  • Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
  • FIG. 1 schematically shows a hot dip galvanizing device.
  • a typical flow of manufacturing steps that leads to a coated metal sheet according to the invention is as follows: A metal slab is cast, and subsequently hot rolled in a hot strip mill to provide a metal strip, that is processed in a pickling line, cold rolled in a cold rolling mill, annealed in a continuous annealing line, and provided with a metal coating in a hot dip galvanizing line, temper rolled in a temper mill, shipped to customers, press formed and painted. Some of these operations can be dispensed with, while it is also possible that some other operations are added to this sequence of events. The skilled person further knows that many operations precede the casting step.
  • FIG 1 shows a hot dip galvanizing device 1 1 to provide a metal coating on one surface 12 or both surfaces 12, 13 of a moving metal sheet 14, comprising a tank 15 that holds a liquid bath of the metal coating 16 that is to be provided on the moving metal sheet 14.
  • Figure 1 shows the application of a stabilization roll 17 and a sink roll 21 to guide the moving metal sheet 14 through the bath, wherein the stabilization roll 17 is provided at a predefined depth (Depth) below a surface level 18 of the liquid bath.
  • This Depth is defined as the distance between the surface level 18 of the liquid bath and an upper edge of the stabilization roll 17. It is remarked that the application of plural stabilization rolls is also possible, wherein then the Depth-parameter relates to the uppermost stabilization roll.
  • Above the liquid bath at least one gas knife 19 is provided, which has an outlet 20 to project -in known way- wiping gas on the metal coating provided on the surface or surfaces 12, 13 of the metal sheet 15 that passes along the gas knife 19.
  • Figure 1 shows both the height H of the gas knife or knives 19 above the liquid bath with reference to its surface level 18, and the distance D of the shown two air knives 19 with reference to the metal sheet 14.
  • Table 1 shows the influence of the height H of the gas knife 19 above the liquid bath, and the influence of the distance D from sheet 14 to knife 19 in relation to the waviness Wsa of the coated metal sheet 14.
  • Table 2 shows the influence of the height H of the gas knife 19 above the liquid bath and the Depth of the at least one stabilizing roll 17 below the surface level 18 of the liquid bath.
  • Table 3 shows the influence of the roughness Ra of the last working rolls in the cold rolling mill in relation to X and their impact on the waviness of the product.
  • stabilization roll 17 is preferably provided at a depth D below surface level 18 of the liquid bath at a value of equal or less than 150 mm, preferably at a value equal or less than 140 mm, more preferably at a value equal or less than 130 mm, most preferably at a value equal or less than 120 mm.
  • Table 3 shows a calculation of the parameters to arrive at a target Wsa and it also shows the measured waviness as Realised Wsa.
  • X D * ln(H * Depth), and Ra stands for the roughness of the working rolls in the last stand of the cold rolling mill.
  • the stabilization roll 17 is preferably provided at a depth D below surface level 18 of the liquid bath of the metal coating 16 in dependence of the roughness Ra of the final working rolls of the cold rolling mill in order to achieve a maximum waviness Wsa of the coated metal sheet. Further preferred values of the roughness Ra are equal or less than 4.5 pm, equal or less than 1.5 pm, and more preferably 0.6 pm or less.
  • the method of coating a metal sheet according to the invention results in a coated metal sheet with a waviness value Wsa equal or less than 0.41 pm; preferably equal or less than 0.35 pm; more preferably equal or less than 0.31 pm; more preferably equal or less than 0.26 pm; most preferably equal or less than 0.23 pm.

Landscapes

  • 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

Method of providing a coating on a metal sheet, wherein a cold rolled metal sheet is subjected to a hot dip galvanizing operation to provide a metal coating on the metal sheet, which hot dip galvanizing operation comprises guiding the metal sheet through a liquid bath of the metal coating with at least one stabilization roll provided at a predefined depth (Depth) below surface level of the liquid bath, and wiping the metal coating that is provided on the metal sheet with at least one gas knife having an outlet to project wiping gas on the metal coating on the metal sheet that passes along the gas knife, wherein a distance (D) of the at least one gas knife to the passing metal sheet and a height (H) of the at least one gas knife above the liquid bath of the metal coating are selected at values so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth) and wherein Wsa is selected at a value representing a targeted maximum waviness.

Description

COATED METAL SHEET, METHOD TO PROVIDE SUCH A COATED METAL SHEET, AND HOT DIP GALVANIZING DEVICE TO MANUFACTURE SUCH A COATED METAL SHEET
The invention relates primarily to a method of providing a coating on a metal sheet, wherein a cold rolled metal sheet is subjected to a hot dip galvanizing operation to provide a metal coating on the metal sheet, which hot dip galvanizing operation comprises guiding the metal sheet through a liquid bath of the metal coating with at least one stabilization roll, wherein each stabilization roll is entirely provided below a predefined depth level below surface level of the liquid bath, and wiping the metal coating that is provided on the metal sheet with at least one gas knife having an outlet to project wiping gas on the metal coating that is provided on the metal sheet that passes along the gas knife.
Such a method of providing a coating on a metal sheet is widely known throughout the iron and steel industry; an exemplary publication showing such a method is GB 2517622.
A problem also acknowledged in GB 2517622 is the waviness of the coated metal sheet, which causes that after providing the coated metal sheet with a film of paint its outer appearance can be less than optimal. One known problem is the appearance of orange skin which is particularly undesirable for outside body parts of automobiles.
GB 2517622 does not particularly provide a workable solution for this problem, for one thing since its disclosure is obscure in relation to the waviness measure it applies.
It is an object of the invention to solve this long existing problem and to provide a workable solution for it. In this connection throughout this application waviness of the coated metal sheet is defined by the measure Wsa (pm) as published by the Deutsche Industry Norm publication SEP 1941 : 2012-05 entitled (in German): Messung des Welligkeitskennwertes Wsa (1-5) an kaltgewaltzten Flacherzeugnissen.
Accordingly the invention proposes a method to manufacture a coated metal sheet, such a coated metal sheet, a hot dip galvanizing device and its combination with a cold rolling mill in accordance with one or more of the appended claims.
In a first aspect of the invention the method of manufacturing a coated metal sheet wherein the upper horizontal plane tangent to the surface of the stabilization roll is located at a predefined depth level (Depth) below the surface level of the liquid bath, has the feature that a distance (D) of a closest gas knife to the passing metal sheet is determined, said distance (D) being measured as the length of a shortest possible virtual straight line between the gas knife and the metal sheet, and a height (H) of a lowest gas knife above the liquid bath of the metal coating is determined and that Depth, D and H are selected at values so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth), wherein Wsa is selected at a value representing a targeted maximum waviness,
In this specification <= symbolizes“less than or equal”.
In applying the above formula, Wsa is selected at a value representing a targeted maximum waviness, and values for distance D, height H and Depth are calculated.
The method of the invention can suitably be executed by providing that D is 9 mm or less, preferably 8 mm or less, preferably 7 mm or less.
Alternatively the method of the invention can be executed by providing that H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
Favourable results can be achieved by providing that Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
In a further aspect of the invention wherein working rolls of a cold rolling mill have a predefined roughness Ra, it is found beneficial that Depth, D and H are selected at values so as to satisfy X<= (Wsa - b) / a, wherein a and b are calculated as follows:
a = -0.00044 * Ra * Ra + 0.00297 * Ra - 0.00067, and
b = 0.03764* Ra * Ra - 0.23352 * Ra + 0.23885.
Ra is determined in accordance with ISO 4287, using a cut-off of 2.5 mm.
More preferred is that Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
According to the invention a coated metal sheet can effectively be provided with a waviness Wsa of 0.41 pm or less, preferably 0.35 pm or less, more preferably 0.31 pm or less, more preferably 0.26 pm or less, most preferably 0.23 pm or less. A suitable minimum value for the targeted maximum waviness Wsa is 0.18 pm.
The invention is also embodied in a hot dip galvanizing device to provide a metal coating on a moving metal sheet, comprising a liquid bath of metal coating to be provided on the metal sheet, and at least one stabilization roll guiding the moving metal sheet through the bath, the upper horizontal plane tangent to the surface of which stabilization roll is located at a predefined depth level (Depth) below the surface level of the liquid bath, and at least one gas knife provided above the liquid bath, said gas knife having an outlet to project wiping gas on the metal coating provided on the metal sheet that in use passes along the gas knife, having a distance (D) of the a closest gas knife to the passing metal sheet, said distance (D) being measured as the length of a shortest possible virtual straight line between the gas knife and the metal sheet, and a height (H) of a lowest gas knife above the liquid bath of the metal coating, characterized in that Depth, D and H are selected so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth), wherein Wsa is representing a targeted maximum waviness.
In one preferred embodiment of the hot dip galvanizing device D is 9 mm or less, preferably 8 mm or less, more preferably 7 mm or less.
In another preferred embodiment of the hot dip galvanizing device H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
Preferably Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
The invention is further embodied in a combination of a hot dip galvanizing device according to any one of claims 8 - 1 1 , with working rolls of a cold rolling mill have a predefined roughness Ra, characterized in that Depth, D and/or H are calculated in dependence of the roughness Ra of the working rolls of the cold rolling mill in relation to a targeted maximum waviness Wsa of the coated metal sheet according to a formula: X<= (Wsa - b) / a, wherein a and b are calculated as follows:
a = -0.00044 * Ra * Ra + 0.00297 * Ra - 0.00067, and
b = 0.03764* Ra * Ra - 0.23352 * Ra + 0.23885.
The objects of the invention can be further promoted when Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
The invention will hereinafter be further elucidated with reference to the drawing of an exemplary embodiment of an apparatus according to the invention that is not limiting as to the appended claims.
In the drawing:
-figure 1 schematically shows a hot dip galvanizing device.
Whenever in the figures the same reference numerals are applied, these numerals refer to the same parts.
A typical flow of manufacturing steps that leads to a coated metal sheet according to the invention, is as follows: A metal slab is cast, and subsequently hot rolled in a hot strip mill to provide a metal strip, that is processed in a pickling line, cold rolled in a cold rolling mill, annealed in a continuous annealing line, and provided with a metal coating in a hot dip galvanizing line, temper rolled in a temper mill, shipped to customers, press formed and painted. Some of these operations can be dispensed with, while it is also possible that some other operations are added to this sequence of events. The skilled person further knows that many operations precede the casting step.
Relevant to the invention is particularly what occurs in the hot dip galvanizing line 6, although of course the surface quality of the steel that arrives at the cold rolling mill also plays a decisive role in the resulting waviness of the final product. It is therefore expressly pointed out that albeit that the disclosure of the instant invention concentrates on the process of hot dip galvanizing, the other processing steps are not without importance and should be maintained at their normal high quality standard. A particular desirable relation between the hot dip galvanizing operation and a prior processing step will accordingly be discussed hereinafter.
Turning now to figure 1 it shows a hot dip galvanizing device 1 1 to provide a metal coating on one surface 12 or both surfaces 12, 13 of a moving metal sheet 14, comprising a tank 15 that holds a liquid bath of the metal coating 16 that is to be provided on the moving metal sheet 14.
Figure 1 shows the application of a stabilization roll 17 and a sink roll 21 to guide the moving metal sheet 14 through the bath, wherein the stabilization roll 17 is provided at a predefined depth (Depth) below a surface level 18 of the liquid bath. This Depth is defined as the distance between the surface level 18 of the liquid bath and an upper edge of the stabilization roll 17. It is remarked that the application of plural stabilization rolls is also possible, wherein then the Depth-parameter relates to the uppermost stabilization roll. Above the liquid bath at least one gas knife 19 is provided, which has an outlet 20 to project -in known way- wiping gas on the metal coating provided on the surface or surfaces 12, 13 of the metal sheet 15 that passes along the gas knife 19. Figure 1 shows both the height H of the gas knife or knives 19 above the liquid bath with reference to its surface level 18, and the distance D of the shown two air knives 19 with reference to the metal sheet 14.
According to the invention the distance D of the at least one gas knife 19 with reference to the passing metal sheet 14 and the height H of the at least one gas knife 19 above the liquid bath of the metal coating 16 are selected at values so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth) and wherein Wsa is selected at a value representing a targeted maximum waviness, and wherein Depth stands for the depth of the at least one stabilization roll 17 below the surface level 18 of the liquid bath.
Table 1 shows the influence of the height H of the gas knife 19 above the liquid bath, and the influence of the distance D from sheet 14 to knife 19 in relation to the waviness Wsa of the coated metal sheet 14.
Table 1
Table 2 shows the influence of the height H of the gas knife 19 above the liquid bath and the Depth of the at least one stabilizing roll 17 below the surface level 18 of the liquid bath. Table 2
It follows from table 1 and table 2 that preferably the distance D of the at least one gas knife 19 to the passing metal sheet 14 is equal or less than 9 mm, more preferably equal or less than 8 mm, even more preferable equal or less than 7 mm, and the height H of the at least one gas knife above the liquid bath of the metal coating is then selected at a value so as to satisfy the formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth).
Alternatively it follows from table 1 and table 2 that the height H of the at least one gas knife 19 above the liquid bath of the metal coating 16 is preferably equal or less than 550 mm, preferably equal or less than 400 mm, more preferably equal or less than 200 mm, and the distance D of the at least one gas knife 19 to the passing metal sheet 14 is selected at a value so as to satisfy the formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth).
Table 3 shows the influence of the roughness Ra of the last working rolls in the cold rolling mill in relation to X and their impact on the waviness of the product.
Table 3
According to the results of Tables 2 and 3 stabilization roll 17 is preferably provided at a depth D below surface level 18 of the liquid bath at a value of equal or less than 150 mm, preferably at a value equal or less than 140 mm, more preferably at a value equal or less than 130 mm, most preferably at a value equal or less than 120 mm.
Table 3 shows a calculation of the parameters to arrive at a target Wsa and it also shows the measured waviness as Realised Wsa. X is determined with the formula X<= (Wsa - b) / a, wherein a and b are calculated as follows:
a = -0.00044 * Ra * Ra + 0.00297 * Ra - 0.00067, and
b = 0.03764* Ra * Ra - 0.23352 * Ra + 0.23885,
wherein X = D*ln(H*Depth), and Ra stands for the roughness of the working rolls in the last stand of the cold rolling mill. From the data found in experimenting with the invention it could be derived that the stabilization roll 17 is preferably provided at a depth D below surface level 18 of the liquid bath of the metal coating 16 in dependence of the roughness Ra of the final working rolls of the cold rolling mill in order to achieve a maximum waviness Wsa of the coated metal sheet. Further preferred values of the roughness Ra are equal or less than 4.5 pm, equal or less than 1.5 pm, and more preferably 0.6 pm or less.
The method of coating a metal sheet according to the invention results in a coated metal sheet with a waviness value Wsa equal or less than 0.41 pm; preferably equal or less than 0.35 pm; more preferably equal or less than 0.31 pm; more preferably equal or less than 0.26 pm; most preferably equal or less than 0.23 pm.
Although the invention has been discussed in the foregoing with reference to exemplary embodiments of the method and devices of the invention, the invention is not restricted to these particular embodiments which can be varied in many ways without departing from the invention. The discussed exemplary embodiments shall therefore not be used to construe the appended claims strictly in accordance therewith. On the contrary, the embodiments are merely intended to explain the wording of the appended claims without intent to limit the claims to these exemplary embodiments. The scope of protection of the invention shall therefore be construed in accordance with the appended claims only, wherein a possible ambiguity in the wording of the claims shall be resolved using these exemplary embodiments.

Claims

1. Method of providing a coating on a metal sheet, wherein a cold rolled metal sheet is subjected to a hot dip galvanizing operation to provide a metal coating on the metal sheet, which hot dip galvanizing operation comprises guiding the metal sheet through a liquid bath of the metal coating with at least one stabilization roll, the upper horizontal plane tangent to the surface of which is located at a predefined depth level (Depth) below the surface level of the liquid bath, and wiping the metal coating that is provided on the metal sheet with at least one gas knife having an outlet to project wiping gas on the metal coating on the metal sheet that passes along the gas knife, characterized in that a distance (D) of a closest gas knife to the passing metal sheet is determined, said distance (D) being measured as the length of a shortest possible virtual straight line between the gas knife and the metal sheet, and a height (H) of a lowest gas knife above the liquid bath of the metal coating is determined and in that Depth, D and H are selected at values so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth), wherein Wsa is selected at a value representing a targeted maximum waviness.
2. Method according to claim 1 , characterized by providing that D is 9 mm or less, preferably 8 mm or less, preferably 7 mm or less.
3. Method according to claim 1 or claim 2, characterized by providing that H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
4. Method according to any one of claims 1 - 3, characterized by providing that Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
5. Method according to any one of claims 1 - 4, wherein working rolls of a cold rolling mill have a predefined roughness Ra, characterized in that Depth, D and H are selected at values so as to satisfy X<= (Wsa - b) / a, wherein a and b are calculated as follows:
a = -0.00044 * Ra * Ra + 0.00297 * Ra - 0.00067, and
b = 0.03764* Ra * Ra - 0.23352 * Ra + 0.23885.
6. Method according to claim 5, characterized by providing that Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
7. Coated metal sheet manufactured in accordance with the method of any one of the previous claims 1 - 6, with a waviness value Wsa of 0.41 pm or less, preferably 0.35 pm or less, more preferably 0.31 pm or less, more preferably 0.26 pm or less, most preferably
0.23 pm or less.
8. Hot dip galvanizing device to provide a metal coating on a moving metal sheet, comprising a liquid bath of metal coating to be provided on the metal sheet, and at least one stabilization roll guiding the moving metal sheet through the bath, the upper horizontal plane tangent to the surface of which stabilization roll is located at a predefined depth level (Depth) below the surface level of the liquid bath, and at least one gas knife provided above the liquid bath, said gas knife having an outlet to project wiping gas on the metal coating provided on the metal sheet that in use passes along the gas knife, having a distance (D) of the a closest gas knife to the passing metal sheet, said distance (D) being measured as the length of a shortest possible virtual straight line between the gas knife and the metal sheet, and a height (H) of a lowest gas knife above the liquid bath of the metal coating, characterized in that Depth, D and H are selected so as to satisfy a formula X <= (Wsa - 0.1395) / 0.0016, wherein X = D*ln(H*Depth), wherein Wsa is representing a targeted maximum waviness.
9. Hot dip galvanizing device according to claim 8, characterized in that D is 9 mm or less, preferably 8 mm or less, more preferably 7 mm or less.
10. Hot dip galvanizing device according to claim 8 or 9, characterized in that H is 550 mm or less, preferably 400 mm or less, more preferably 200 mm or less.
1 1. Hot dip galvanizing device according to any one of claims 8 - 10, characterized in that Depth is 150 mm or less, preferably 140 mm or less, more preferably 130 mm or less, most preferably 120 mm or less.
12. Combination of a hot dip galvanizing device according to any one of claims 8 - 1 1 , with working rolls of a cold rolling mill have a predefined roughness Ra, characterized in that Depth, D and/or H are calculated in dependence of the roughness Ra of the working rolls of the cold rolling mill in relation to a targeted maximum waviness Wsa of the coated metal sheet according to a formula X<= (Wsa - b) / a, wherein a and b are calculated as follows:
a = -0.00044 * Ra * Ra + 0.00297 * Ra - 0.00067, and
b = 0.03764* Ra * Ra - 0.23352 * Ra + 0.23885.
13. Combination of a hot dip galvanizing device with working rolls of a cold rolling mill according to claim 12, characterized in that Ra is 4.5 pm or less, 1.5 pm or less, preferably 0.6 pm or less.
EP18788682.5A 2018-10-02 2018-10-02 Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet Pending EP3861146A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2018/076874 WO2020069734A1 (en) 2018-10-02 2018-10-02 Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet

Publications (1)

Publication Number Publication Date
EP3861146A1 true EP3861146A1 (en) 2021-08-11

Family

ID=63878634

Family Applications (1)

Application Number Title Priority Date Filing Date
EP18788682.5A Pending EP3861146A1 (en) 2018-10-02 2018-10-02 Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet

Country Status (2)

Country Link
EP (1) EP3861146A1 (en)
WO (1) WO2020069734A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115233129A (en) * 2022-07-18 2022-10-25 首钢京唐钢铁联合有限责任公司 A control method and device for hot-dip galvanizing of strip steel and strip steel

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2119804A1 (en) * 2008-05-14 2009-11-18 ArcelorMittal France Method of manufacturing a covered metal strip with improved appearance
WO2018073116A2 (en) * 2016-10-17 2018-04-26 Tata Steel Ijmuiden B.V. Method for producing a steel strip for painted parts

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2139119C (en) * 1993-04-28 2001-03-13 Kazunari Andachi Method for adjusting coating weight by gas wiping
WO2014135753A1 (en) * 2013-03-06 2014-09-12 Arcelormittal Investigacion Y Desarrollo, S.L. A method for manufacturing a metal sheet with a znal coating and with optimised drying, corresponding metal sheet, part and vehicle
US11174530B2 (en) * 2016-10-17 2021-11-16 Tata Steel Ijmuiden B.V. Steel for painted parts
EP3382054A1 (en) * 2017-03-30 2018-10-03 Tata Steel IJmuiden B.V. Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2119804A1 (en) * 2008-05-14 2009-11-18 ArcelorMittal France Method of manufacturing a covered metal strip with improved appearance
WO2018073116A2 (en) * 2016-10-17 2018-04-26 Tata Steel Ijmuiden B.V. Method for producing a steel strip for painted parts

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2020069734A1 *

Also Published As

Publication number Publication date
WO2020069734A1 (en) 2020-04-09

Similar Documents

Publication Publication Date Title
JP6009100B2 (en) Method for producing metal sheets using ZnAl coating and optimized wiping, corresponding metal sheets, parts and vehicles
JP7060693B2 (en) Zinc alloy plated steel and its manufacturing method
RU2501883C2 (en) Production of metal strip with coat that features improved appearance
CA2961427C (en) Cold-rolled and recrystallization annealed flat steel product, and method for the production thereof
EP3205741A1 (en) Continuous hot-dip metal plating method, hot-dip zinc-plated steel strip, and continuous hot-dip metal plating equipment
JP2015520797A (en) Steel sheet with a coating that provides sacrificial cathodic protection, method of manufacturing a part using such a sheet, and resulting part
JP2011521103A (en) Method for producing coated metal strip with improved appearance
RU2656898C1 (en) Steel sheet with high workability that has a coating from al-based alloys obtained by submersion in melt
RU2636217C1 (en) Method of manufacturing details with low side strain of electro-galvanized metal sheet and relevant detail and vehicle
CA2945560C (en) Method for producing a steel component which is shaped by hot-forming a steel sheet which has a metal coating
CN103769431B (en) A kind of production method of automobile exterior panel
EP3488025B1 (en) Method for providing a zn-al-mg coating
MX2019014034A (en) Method of manufacturing a continuous hot dip coated steel strip and hot dip coated steel sheet.
EP3354359B1 (en) Method for manufacturing plated steel sheet having excellent clarity of image after coating
KR20100057908A (en) Equipment for producing hot dip galvanized steel plate
RU2409698C2 (en) Controlled reduction of thickness of hot rolled steel strip with coating produced by immersion into melt; installation for this procedure
EP3861146A1 (en) Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet
EP2521801B1 (en) Metal coated steel strip
US20190085445A1 (en) Method and installation for coating a scaled hot-rolled strip
EP3382054A1 (en) Coated metal sheet, method to provide such a coated metal sheet, and hot dip galvanizing device to manufacture such a coated metal sheet
JP6354072B2 (en) Temper rolling method and steel plate manufacturing method using the same
KR20240041338A (en) Hot rolled steel sheet and manufacturing method thereof
JP6772930B2 (en) Manufacturing method of hot-dip galvanized steel sheet and hot-dip galvanized steel sheet
JP2002212583A (en) Tempering rolling liquid composition having excellent adhesion suppressing property of zinc abrasive powder to rolling roll
JP6266905B2 (en) Aluminum alloy plate for can body and manufacturing method thereof

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20210503

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20240430