AU2012237449A1 - Method for coating a moving steel strip with a metal or metal alloy coating - Google Patents
Method for coating a moving steel strip with a metal or metal alloy coating Download PDFInfo
- Publication number
- AU2012237449A1 AU2012237449A1 AU2012237449A AU2012237449A AU2012237449A1 AU 2012237449 A1 AU2012237449 A1 AU 2012237449A1 AU 2012237449 A AU2012237449 A AU 2012237449A AU 2012237449 A AU2012237449 A AU 2012237449A AU 2012237449 A1 AU2012237449 A1 AU 2012237449A1
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- Australia
- Prior art keywords
- metal
- steel strip
- bath
- coating
- metal alloy
- 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.)
- Abandoned
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 103
- 239000010959 steel Substances 0.000 title claims abstract description 103
- 239000002184 metal Substances 0.000 title claims abstract description 93
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 92
- 238000000576 coating method Methods 0.000 title claims abstract description 78
- 239000011248 coating agent Substances 0.000 title claims abstract description 71
- 229910001092 metal group alloy Inorganic materials 0.000 title claims abstract description 61
- 238000000034 method Methods 0.000 title claims abstract description 32
- 239000011888 foil Substances 0.000 claims abstract description 43
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 36
- 229910052725 zinc Inorganic materials 0.000 claims description 36
- 239000011701 zinc Substances 0.000 claims description 36
- 239000002245 particle Substances 0.000 claims description 20
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 9
- 229910045601 alloy Inorganic materials 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 7
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 5
- 229910052718 tin Inorganic materials 0.000 claims description 4
- 239000007789 gas Substances 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims description 2
- 239000001301 oxygen Substances 0.000 claims description 2
- 229910052760 oxygen Inorganic materials 0.000 claims description 2
- 230000006698 induction Effects 0.000 claims 1
- 239000000463 material Substances 0.000 description 12
- 238000003618 dip coating Methods 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 229910001297 Zn alloy Inorganic materials 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 229910052742 iron Inorganic materials 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000011135 tin Substances 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 239000002436 steel type Substances 0.000 description 3
- 229910000838 Al alloy Inorganic materials 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 230000005674 electromagnetic induction Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 230000005764 inhibitory process Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 241001137251 Corvidae Species 0.000 description 1
- -1 Nai-yong Tang Substances 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- 229910000611 Zinc aluminium Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000012790 confirmation Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005246 galvanizing Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 235000015108 pies Nutrition 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 210000004894 snout Anatomy 0.000 description 1
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
- C23C2/14—Removing excess of molten coatings; Controlling or regulating the coating thickness
- C23C2/22—Removing excess of molten coatings; Controlling or regulating the coating thickness by rubbing, e.g. using knives, e.g. rubbing solids
-
- 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
-
- 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
-
- 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
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
The invention relates to a method for coating a moving steel strip with a metal or metal alloy coating, wherein the steel strip runs through a bath of molten metal or metal alloy to coat the steel strip, and the coated steel strip is wiped to control the thickness of the coating using foils or sheets. According to the invention the bath of molten metal has a volume that is at most 10.000 times the volume V of the coating on the steel strip per second, volume V in m
Description
WO 2012/130464 PCT/EP2012/001401 METHOD FOR COATING A MOVING STEEL STRIP WITH A METAL OR METAL ALLOY COATING The invention relates to a method for coating a moving steel strip with a metal or 5 metal alloy coating, wherein the steel strip runs through a bath of molten metal or metal alloy to coat the steel strip, and the coated steel strip is wiped to control the thickness of the coating. Such a method is well known in the art and is called hot dip coating. Usually hot dip coating is performed using a container with a molten metal bath, through which the 10 steel strip is guided using a submerged guiding roll. Normally the strip is forwarded from an annealing line and enters the metal bath through a snout under an angle at an elevated temperature. After rounding the guiding roll, the steel strip leaves the metal bath in a vertical direction, on both sides coated with a metal layer. For commercial use this metal coating is too thick, and a wiping device is present not far above the 15 metal bath to wipe off the surplus of metal. The metal normally is zinc, a zinc alloy, aluminum or an aluminum alloy, but the use of other metals is also possible. Usually air knives are used to wipe the metal from the steel strip. Since the steel strip can be up to 2 meters in width, the metal bath often has a volume of about 24 cubic meters. Recently a novel type of wiping device has been developed, as described in 20 Belgian patent application 1018202. This wiping device mainly consists of two foils or sheets which are pressed towards the steel strip using a number of springs. This wiping device is placed above for instance a zinc bath as described hereinabove in the place of the usual air knives. When the zinc coated steel strip moves through a gap between the foils of the wiping device, the foils are more or less planing, floating or 25 gliding on the liquid zinc on the steel strip, similar to the well-known aquaplaning effect. By adjusting the pressure exerted by the springs in relation to the speed of the strip, the thickness of the zinc coating leaving the wiping device can be controlled. In this way coatings with a reduced thickness as compared to coatings formed using air knives can be produced. 30 However, it has been found that the foil wiping device of BE 1018202 can not be used in practice because zinc dross particles that are formed in and on the zinc bath are entrained with the zinc that forms the coating on the steel strip. Zinc dross particles contain iron and aluminum and are quite hard. The zinc dross particles get stuck between the foil of the wiping device and the steel strip and cause scratches on the 35 steel strip. For this reason, the wiping device of BE 1018202 is not used in practice. CONFIRMATION COPY WO 2012/130464 PCT/EP2012/001401 2 It is an object of the invention to provide a method for coating moving steel strip material with a metal or metal alloy coating by which can coat strip material with a higher velocity of the strip. It is another object of the invention to provide a method for coating moving steel 5 strip material with a metal or metal alloy coating which can produce metal coatings on steel strip which are reduced in thickness as compared to the existing commercial apparatus. It is a further object of the invention to provide a method for coating moving steel strip material with a metal or metal alloy coating that is improved as compared to 10 existing commercial hot dip coating. It is a still further object of the invention to provide a method for coating moving steel strip material with a metal or metal alloy coating that is easier to use than existing commercial hot dip coating. It is also an object of the invention to provide a method for coating moving steel 15 strip material with a metal or metal alloy coating that is less costly in use than existing commercial hot dip coating. According to the invention, one or more of these objects are reached with a method for coating a moving steel strip with a metal or metal alloy coating, wherein the steel strip runs through a bath of molten metal or metal alloy to coat the steel strip, and 20 the coated steel strip is wiped to control the thickness of the coating using foils or sheets, wherein the bath of molten metal has a volume that is at most 10.000 times the volume V of the coating on the steel strip per second, volume V in m 3 being given by the formula V = 2 x d x w x s, wherein d = the thickness of the coating in meters 25 w = the width of the strip in meters s = the velocity of the strip in meters per second. Using such a volume of the bath, the dross particles that grow in the bath can remain small enough not to stick between the steel strip and the foils or sheets of the wiping device. The volume of the bath to be used will at least depend on the coating 30 metal or metal alloy, the growing rate of the dross particles, the coating thickness on the steel sheet and the velocity of the steel strip. For this reason, the volume of the bath is dependant on these last parameters. In this way, the known foil wiper as discussed above can be used, which provides the possibility of a high strip velocity and thin coatings. 35 A relatively small bath has also the advantage that the coating system using the bath according to the invention is much more flexible than the known hot dip coating, WO 2012/130464 PCT/EP2012/001401 3 because it is not necessary to keep a large volume of metal at a high temperature anymore, and because there are less or no metal losses due to the forming of metallic dross on the surface of the metal bath. According to a preferred embodiment, the bath of molten metal has a volume that 5 is at most 2000 times the volume V of the coating on the steel strip per second, preferably a volume that is at most 500 times the volume of the coating on the steel strip per second, more preferably a volume that is at most 100 times the volume of the coating on the steel strip per second. The smaller the volume of the bath, the easier it is to keep the oxidic or metallic dross particles at a size such that they do not stick 10 between the steel strip and the foils or sheets of the wiping device. A smaller bath also has the advantage that a change of coating material on the steel strip can be executed faster. Preferably the bath of molten metal has a volume such that metallic dross particles formed in the bath of molten metal or metal alloy on average are smaller than 15 the thickness of the metal or metal alloy coating on the steel strip after wiping using foils or sheets. Since the bath of molten metal or metal alloy thus should contain only small metallic dross particles, in the range of a few micrometers, the bath will have a preferred volume in the order of a few liters. The small metallic dross particles cannot be entrapped between the steel strip and a foil or sheet for wiping the metal or metal 20 alloy coated steel, nor cause scratches. Preferably the wiping of the molten metal or metal alloy is performed using foils or sheets which are pressed towards the moving steel strip, wherein the moving of the steel strip causes a hydrodynamic lifting force by the coating which is in equilibrium with the pressure exerted on the foils or sheets. This is the way the foils or sheets 25 provide the coating according to BE 1018202. According to a preferred embodiment the bath of molten metal or metal alloy is positioned under the foils or sheets. The steel sheet thus enters the bath from below, which means that for instance in case of emergency the foil wiping device can be opened and the bath can be emptied, without contaminating the steel strip. A change 30 of width or thickness of the steel strip, for which the foil wiping device has to be opened, can be performed without emptying the bath. It is also possible to have the steel strip enter the bath from above, but this does not give this advantage. Preferably the steel strip is moved vertical or under an angle of at most 45 degrees with the vertical first through the bath of molten metal or metal alloy and than 35 in between the foils or sheets. In this way it is easy to guide the strip.
WO 2012/130464 PCT/EP2012/001401 4 According to a preferred embodiment the bath of molten metal or metal alloy is in fluid connection with the metal or metal alloy layers between the steel strip and the foils or sheets. This means that the metal or metallic alloy in the bath is in direct contact with the metal or metal alloy layers between the foils or sheets and the steel 5 strip, and thus that no un-wiped coatings are formed before a foil wiping device forms the coatings as these are desired. According to a preferred embodiment a replenishing bath with metal or metal alloy is used to refill the bath of molten metal or metal alloy. Since the bath through which the steel strip runs is small, this bath should preferably be refilled using a 10 replenishing bath. Preferably electromagnetic induction is used to retain the molten metal or metal alloy in a container for the bath of molten metal or metal alloy. This is especially important in the situation that the bath is situated under the foils or sheets, but such electromagnetic induction is also useful when the bath is situated above the foils or 15 sheets. According to a preferred embodiment the metal or metal alloy in the bath is protected from oxygen in the surrounding air. In this way the forming of oxidic dross films is reduced. Preferably, for this a shielding gas is used to protect the molten metal or metal alloy in the bath from outside air. 20 According to a preferred embodiment the foils or sheets are pressed towards the strip to control the thickness of the metal or metal alloy coating. The pressing can be executed using any one of the usual physical possibilities, such as hydraulically, by using springs, by using pies elements, et cetera. Preferably the steel strip is annealed before entering the bath of metal or metal 25 alloy. Annealing usually has to be performed after a steel strip is cold rolled, and the annealing also provides a desired surface quality for hot dip coating with a metal or metal alloy coating. According to a preferred embodiment the steel strip is heated to a predetermined temperature before entering the bath of metal or metal alloy. Especially for third 30 generation high strength steel types it is often necessary to perform an additional heating step just before the steel strip enters the bath with metal or metal alloy coating material. In a preferred embodiment the temperature of the bath of metal or metal alloy is higher than the temperature of the steel strip when entering the bath, preferably the 35 temperature of the bath being 0 - 30 0C higher than the temperature of the steel strip, more preferably 10 - 20 *C. When the coating material is zinc or a zinc alloy, the strip WO 2012/130464 PCT/EP2012/001401 5 entry temperature (SET) preferably is the highest melting temperature of the coating material plus a factor C1, wherein C1 is between 10 and 60 *C, and more preferably C1 is between 20 and 40 *C. With this value of the SET, the temperature of the bath is SET plus C2, wherein C2 is between 0 and 30 *C, and preferably C2 is between 10 5 and 20 0C. In this way the temperature of the steel strip is lower than the temperature of the bath and therefore the forming of dross particles in the bath is retarded. Preferably the metal or metal alloy coated steel strip is cooled after leaving the bath of metal or metal alloy. Cooling, especially fast cooling, is necessary for third generation high strength steel types, but other steel type must usually be cooled as 10 well after leaving the metal or metal alloy bath. According to a preferred embodiment the steel strip has a width of 0.75 to 2.25 meters. These widths are economical to coat using the method according to the invention. Preferably the steel strip has a velocity of 2 to 10 m/s. This velocity is at the high 15 end and higher than the speed that can be used to hot dip coat using air knives. Preferably the metal or metal alloy coating has a thickness of 1 to 30 pm on each side of the steel strip. According to a preferred embodiment the metal is zinc, magnesium, aluminum or tin, or an alloy of one of these metals. Especially zinc, magnesium or aluminum are 20 used for hot dip coating, but also alloys thereof such as an alloy of zinc and aluminum or an alloy of zinc and aluminum and magnesium. Tin can also be used, often for very thin coatings. The invention will be elucidated in the following example. A steel strip with is moved in a downward direction through a zinc bath and 25 subsequently through a foil wiping device. The zinc bath is contained in a container which forms one apparatus with the foil wiping device, such that the zinc in the zinc bath is directly fed into the zinc layers between the foils and the steel strip. The foils are pressed towards the steel strip such that a coating is formed on the steel strip. A replenishing bath is used to fill the bath with molten zinc, such that the volume in the 30 zinc bath remains substantially constant. The zinc bath will be protected by a shielding gas, such that no oxidation by the outside air takes place. The zinc layers between the strip and the foils have a velocity zero at the surface of the foils and the velocity of the steel strip at the surface of the steel strip. Thus, the zinc coating formed at the surface of the strip has approximately half the thickness of 35 the zinc layer between a foil and the steel strip.
WO 2012/130464 PCT/EP2012/001401 6 Dross particles are formed in the zinc bath due to the iron in the steel strip. These dross particles are taken along from the zinc bath with the zinc that is used for coating the steel strip. These dross particles should all be small enough to pass in between the foils and the steel strip. When a dross particle has become too large, it 5 will get stuck between a foil and the steel strip, and cause scratches on the steel strip. For this reason, the zinc dross particles should have an average size that is smaller than half the thickness of the zinc layer between the foils and the steel strip, which is the same as being smaller than the thickness of the zinc coating leaving the foil wiping device. 10 The volume V of the coating on the steel strip per second is 2 x d x w x s. For a normal operation, the thickness of the coating is 5 x 10-6 m (= 5 pm), the width is for instance 1 meter, and the velocity of the strip is 2 meter per second. The volume V then is 2 x 5 x 10- x 1 x 2 = 2 x 10-5 M 3 , this is 0,02 liters or 20 cm 3 . When a bath is used that is 100 times the volume V of the coating on the strip per second, the bath will 15 thus have a volume of 2 liters. From the literature (Modeling of iron dissolution during hot dip galvanizing of steel strip, O'Dell, Charles, Vlot and Randle, Material science and technology, 2004) it is known that in traditional zinc bath operation an inhibition layer creation is essential to restrict iron dissolution into the bath because of high residence times, To create an 20 inhibition layer thickness of 100 nm requires about 0,15 second submerging time. The average residence time of dross particles for a zinc coating thickness of 10 pm then drops from 400.000 seconds in a traditional bath to 125 seconds in the bath having a volume of 0,005 m3. With a dross growth rate of 0,05 pm/s (Thermodynamics and kinetics of alloy formation in galvanized coating, Nai-yong Tang, Zinc Based Steel 25 coating systems production and performance, February 1998, Texas) the dross particle size will be about 6 pm. Thus, the average zinc dross particle size is smaller than the thickness of the zinc coating of 10 pm. The reduced bath volume makes online bath changes possible. The reduced submerging time enables production of a new class of high strength steel. 30 It will be clear to the skilled person that other metal coating can also be used, such as aluminium or tin, or an alloy of zinc, aluminium or tin, respectively. It will also be clear to the skilled person that other process steps can be added to the method, such as annealing before the hot dip coating, and heating before and/or cooling after the hot dip coating. 35 It will also be clear to the skilled person that the design of the bath according to the invention needs to be such that "dead spots" in the liquid flow are to be avoided. In WO 2012/130464 PCT/EP2012/001401 7 dead spots, the liquid substantially remains on the same place and is not used for coating the steel strip. In such "dead spots" the residence time of the liquid coating material will become too high and large dross particles could be formed.
Claims (18)
1. Method for coating a moving steel strip with a metal or metal alloy coating, 5 wherein the steel strip runs through a bath of molten metal or metal alloy to coat the steel strip, and the coated steel strip is wiped to control the thickness of the coating using foils or sheets, wherein the bath of molten metal has a volume that is at most 10.000 times the volume V of the coating on the steel strip per second, volume V in m 3 being given by the formula V = 2 x d x w x s, wherein 10 d = the thickness of the coating in meters w = the width of the strip in meters s = the velocity of the strip in meters per second.
2. Method according to claim 1, wherein the bath of molten metal has a volume that 15 is at most 2000 times the volume V of the coating on the steel strip per second, preferably a volume that is at most 500 times the volume of the coating on the steel strip per second, more preferably a volume that is at most 100 times the volume of the coating on the steel strip per second. 20
3. Method according to claim 1 or 2, wherein the bath of molten metal has a volume such that metallic dross particles formed in the bath of molten metal or metal alloy on average are smaller than the thickness of the metal or metal alloy coating on the steel strip after wiping. 25
4. Method according to claim 1, 2 or 3, wherein the wiping of the molten metal or metal alloy is performed using foils or sheets which are pressed towards the moving steel strip, wherein the moving of the steel strip causes a hydrodynamic lifting force by the coating which is in equilibrium with the pressure exerted on the foils or sheets. 30
5. Method according to claim 1, 2, 3 or 4, wherein the bath of molten metal or metal alloy is positioned under the foils or sheets, and preferably the steel strip is moved vertical or under an angle of at most 45 degrees with the vertical first through the bath of molten metal or metal alloy and than in between the foils or 35 sheets. WO 2012/130464 PCT/EP2012/001401 9
6. Method according to any one of the preceding claims, wherein the bath of molten metal or metal alloy is in fluid connection with the metal or metal alloy layers between the steel strip and the foils or sheets. 5
7. Method according to any one of the preceding claims, wherein a replenishing bath with metal or metal alloy is used to refill the bath of molten metal or metal alloy.
8. Method according to any one of the preceding claims, wherein electromagnetic 10 induction is used to retain the molten metal or metal alloy in a container for the bath of molten metal or metal alloy.
9. Method according to any one of the preceding claims, wherein the metal or metal alloy in the bath is protected from oxygen in the surrounding air, and preferably a 15 shielding gas is used to protect the molten metal or metal alloy in the bath from outside air.
10. Method according to any one of the preceding claims, wherein the foils or sheets are pressed towards the strip to control the thickness of the metal or metal alloy 20 coating.
11. Method according to any one of the preceding claims, wherein the steel strip is annealed before entering the bath of metal or metal alloy. 25
12. Method according to any one of the preceding claims, wherein the steel strip is heated to a predetermined temperature before entering the bath of metal or metal alloy.
13. Method according to any one of the preceding claims, wherein the temperature of 30 the bath of metal or metal alloy is higher than the temperature of the steel strip when entering the bath, preferably the temperature of the bath being 0 - 30 *C higher than the temperature of the steel strip, more preferably 10 - 20 *C.
14. Method according to any one of the preceding claims, wherein the metal or metal 35 alloy coated steel strip is cooled after leaving the bath of metal or metal alloy. WO 2012/130464 PCT/EP2012/001401 10
15. Method according to any one of the preceding claims, wherein the steel strip has a width of 0.75 to 2.25 meters.
16. Method according to any one of the preceding claims, wherein the steel strip has 5 a velocity of 2 to 10 m/s.
17. Method according to any one of the preceding claims, wherein the metal or metal alloy coating has a thickness of 1 to 30 pm on each side of the steel strip. 10
18. Method according to any one of the preceding claims, wherein the metal is zinc or aluminum or tin or an alloy of one of these metals.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP11002610.1 | 2011-03-30 | ||
| EP11002610 | 2011-03-30 | ||
| PCT/EP2012/001401 WO2012130464A1 (en) | 2011-03-30 | 2012-03-30 | Method for coating a moving steel strip with a metal or metal alloy coating |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2012237449A1 true AU2012237449A1 (en) | 2013-10-17 |
Family
ID=45926519
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2012237449A Abandoned AU2012237449A1 (en) | 2011-03-30 | 2012-03-30 | Method for coating a moving steel strip with a metal or metal alloy coating |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US20140023797A1 (en) |
| EP (1) | EP2691552A1 (en) |
| JP (1) | JP2014509693A (en) |
| KR (1) | KR20140014247A (en) |
| CN (1) | CN103459649A (en) |
| AU (1) | AU2012237449A1 (en) |
| CA (1) | CA2831178A1 (en) |
| WO (1) | WO2012130464A1 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2831177C (en) | 2011-03-30 | 2016-05-24 | Tata Steel Nederland Technology B.V. | Apparatus for coating a moving strip material with a metallic coating material |
| CN105132846A (en) * | 2015-10-14 | 2015-12-09 | 江苏中远稀土新材料有限公司 | Non-deformation hot galvanizing technique for thin rolled steel component for industrial use and civilian use |
| CN105839041B (en) * | 2016-04-14 | 2018-08-07 | 上海大学 | A kind of the or immersion method and its equipment of prepared composition graded alloy material |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3962501A (en) * | 1972-12-15 | 1976-06-08 | Nippon Steel Corporation | Method for coating of corrosion-resistant molten alloy |
| US4082864A (en) * | 1974-06-17 | 1978-04-04 | Fiber Materials, Inc. | Reinforced metal matrix composite |
| US4024309A (en) * | 1975-03-17 | 1977-05-17 | Ronald P. Wilder | Foam glass structural element and method of producing |
| US4078103A (en) * | 1975-04-17 | 1978-03-07 | Armco Steel Corporation | Method and apparatus for finishing molten metallic coatings |
| US4029478A (en) * | 1976-01-05 | 1977-06-14 | Inland Steel Company | Zn-Al hot-dip coated ferrous sheet |
| JPS589964A (en) * | 1981-07-10 | 1983-01-20 | Nisshin Steel Co Ltd | Method and device for controlling plating thickness in continuous hot dipping of steel strip |
| CA1306614C (en) * | 1987-06-08 | 1992-08-25 | Ralph Harris | Producing volatile metals |
| CA2225537C (en) * | 1996-12-27 | 2001-05-15 | Mitsubishi Heavy Industries, Ltd. | Hot dip coating apparatus and method |
| FR2773820B1 (en) * | 1998-01-22 | 2000-02-25 | Snecma | LIQUID METALLIC FIBER COATING PROCESS |
| FR2798937A3 (en) * | 1999-09-24 | 2001-03-30 | Lorraine Laminage | Installation for the coating of metal strip, defiling rectilinearly, by immersion in a bath of liquid coating material, notably for the galvanization of steel strip |
| BE1018202A3 (en) | 2008-06-27 | 2010-07-06 | Ct Rech Metallurgiques Asbl | Device for spin hydrodynamics a band metal scroll contunu. |
| FR2945823B1 (en) * | 2009-05-25 | 2011-10-14 | Snecma | METHOD AND DEVICE FOR LIQUID METALLIC COATING OF FIBERS OF CERAMIC MATERIAL |
-
2012
- 2012-03-30 WO PCT/EP2012/001401 patent/WO2012130464A1/en active Application Filing
- 2012-03-30 EP EP12711577.2A patent/EP2691552A1/en not_active Withdrawn
- 2012-03-30 CN CN2012800166970A patent/CN103459649A/en active Pending
- 2012-03-30 KR KR1020137027911A patent/KR20140014247A/en not_active Application Discontinuation
- 2012-03-30 US US14/008,545 patent/US20140023797A1/en not_active Abandoned
- 2012-03-30 AU AU2012237449A patent/AU2012237449A1/en not_active Abandoned
- 2012-03-30 CA CA2831178A patent/CA2831178A1/en not_active Abandoned
- 2012-03-30 JP JP2014501482A patent/JP2014509693A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| CN103459649A (en) | 2013-12-18 |
| JP2014509693A (en) | 2014-04-21 |
| KR20140014247A (en) | 2014-02-05 |
| CA2831178A1 (en) | 2012-10-04 |
| WO2012130464A1 (en) | 2012-10-04 |
| US20140023797A1 (en) | 2014-01-23 |
| EP2691552A1 (en) | 2014-02-05 |
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