EP0397952A1 - A method and apparatus for the continuous etching and aluminum plating of stainless steel strips - Google Patents
A method and apparatus for the continuous etching and aluminum plating of stainless steel strips Download PDFInfo
- Publication number
- EP0397952A1 EP0397952A1 EP89810362A EP89810362A EP0397952A1 EP 0397952 A1 EP0397952 A1 EP 0397952A1 EP 89810362 A EP89810362 A EP 89810362A EP 89810362 A EP89810362 A EP 89810362A EP 0397952 A1 EP0397952 A1 EP 0397952A1
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- EP
- European Patent Office
- Prior art keywords
- strip
- bath
- enclosure
- aluminum
- molten
- 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.)
- Granted
Links
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 32
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 32
- 238000005530 etching Methods 0.000 title claims abstract description 18
- 238000000034 method Methods 0.000 title claims abstract description 15
- 238000007747 plating Methods 0.000 title claims description 13
- 239000010935 stainless steel Substances 0.000 title claims description 6
- 229910001220 stainless steel Inorganic materials 0.000 title claims description 6
- 230000002829 reductive effect Effects 0.000 claims abstract description 11
- 229910052751 metal Inorganic materials 0.000 claims abstract description 10
- 239000002184 metal Substances 0.000 claims abstract description 10
- 238000003618 dip coating Methods 0.000 claims abstract description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 26
- 238000004157 plasmatron Methods 0.000 claims description 15
- 229910052786 argon Inorganic materials 0.000 claims description 13
- 238000000576 coating method Methods 0.000 claims description 12
- 239000011248 coating agent Substances 0.000 claims description 9
- 230000005291 magnetic effect Effects 0.000 claims description 8
- 229910000831 Steel Inorganic materials 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 5
- 239000010959 steel Substances 0.000 claims description 5
- 230000001464 adherent effect Effects 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 239000010410 layer Substances 0.000 claims description 3
- 208000036366 Sensation of pressure Diseases 0.000 claims 1
- 235000019628 coolness Nutrition 0.000 claims 1
- 239000011241 protective layer Substances 0.000 claims 1
- 238000005096 rolling process Methods 0.000 claims 1
- 238000009736 wetting Methods 0.000 claims 1
- 235000010210 aluminium Nutrition 0.000 description 15
- 239000007789 gas Substances 0.000 description 13
- 239000000758 substrate Substances 0.000 description 9
- 238000009434 installation Methods 0.000 description 7
- 101100493710 Caenorhabditis elegans bath-40 gene Proteins 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 238000001020 plasma etching Methods 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910000906 Bronze Inorganic materials 0.000 description 1
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 239000010974 bronze Substances 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 229910000423 chromium oxide Inorganic materials 0.000 description 1
- KPLQYGBQNPPQGA-UHFFFAOYSA-N cobalt samarium Chemical compound [Co].[Sm] KPLQYGBQNPPQGA-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- KUNSUQLRTQLHQQ-UHFFFAOYSA-N copper tin Chemical compound [Cu].[Sn] KUNSUQLRTQLHQQ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000010849 ion bombardment Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000007750 plasma spraying Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000001552 radio frequency sputter deposition Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
- 230000000153 supplemental effect Effects 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Images
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
- C23C2/003—Apparatus
- C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
- C23C2/004—Snouts
-
- 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
- C23C2/003—Apparatus
- C23C2/0035—Means for continuously moving substrate through, into or out of the bath
-
- 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
- C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- 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
Definitions
- the installation represented on Fig. 1 comprises an enclosure consisting of four successive tubular compartments 1a - 1d connected to each other by reduced diameter apertures and terminated by a spout 2 which penetrates into a bath 3 of molten aluminum 4.
- a continuous stainless strip 5 is circulated within the installation starting from a feed-spool 6 up to a take-up spool 7 at the end of the line.
- the strip is guided by main rollers 8, 9, 10 and 11, and by seal-roll chambers 12a to 12e which also provide gas pressure isolation between compartments and from the outside. Seal-roll chambers are detailed in document EP-A-176 109 incorporated by reference.
- the components 1a to 1d of the present installation are provided with input ducts 13a to 13d, respectively, and output ducts 14a to 14d, respectively.
- the output ducts are used in connection with one or more suitable pumps to establish a reduced pressure within the enclosure.
- the input ducts are used to introduce a gas at low pressure to sustain the plasmatron discharges in the compartments; this gas is usually argon.
- Each compartment of the present enclosure 1 contains a plasmatron device 24 (individual plasmatron are given the reference numbers 24a to 24d) which is represented on an enlarged scale in fig. 2.
- a plasmatron device of the kind used in the present embodiment comprises a magnet frame 15 carrying three magnets, respectively 161, 162 and 163 arranged in order of alternating polarity, so that the magnetic field created by said magnets is closed in a confinement space between the magnets and an anode 18, as represented by reference 17 on the drawing.
- the magnets are placed very close to the path of the circulating strip 5 so that the strip will circulate within the confinement space 17 while being prevented from rubbing against the magnets by means of rolls 19 made of a non-magnetic material, for instance bronze or austenitic steel.
- the anode 18 is connected to a positive terminal of an electric generator (not shown) by a lead passing through an insulator 20 (for instance of steatite).
- the strip 5 moves along its path in the enclosure 1 and each portion thereof passes successively in the discharge zones 17 of each successive plasmatron device 24a to 24d.
- the number of compartments with respective plasmatron can be more than 4, for instance 6, 8 or more.
- the etched strip is guided through seal-roll chamber 12e and spout 2 into the bath of molten aluminum 4, whereby it becomes coated with a film of aluminum.
- the coating weight (thickness) is controlled by means of a conventional wiping apparatus W or an equivalent, after which the aluminum solidifies by cooling. Then the plated strip is stored over take-up spool 7.
- the strip 5 After being plated with Al by its passage in bath 40, the coating weight being conventionally controlled by wiping (see W in the drawing) the strip 5 leaves the enclosure through gas sealed passage means 44a to 44d which are of similar cons truction as the aforementioned passages 32a to 32d, and is stored over a take-up spool 45.
Abstract
Description
- The present invention concerns a method and apparatus for plating stainless steel strips with aluminum in which, prior to plating, the strip is cleaned by passing into an electric gaseous discharge.
- The continuous cleaning or etching of defilading elongated substrates such as wire, strips, bands and the like by ion bombardment prior to coating with another material or metal is known. This technique is indeed considered much more effective in the case of high chromium content alloys than the more conventional high temperature reductive cleaning treatments because chromium oxide is difficult to reduce and poor reduction efficiency is likely to cause problems of adhesion of the final aluminum layer. Some pertinent prior art in this field is summarized below.
-
- (1) DDR-120.474 (HEISIG et al.) discloses an installation for the precleaning by sputtering before plating under vacuum of a stainless strip. The precleaning unit can be integral with or separated from the plating unit itself. The precleaning unit comprises a plurality of magnetron elements arranged consecutively along the defilading strip (see the drawing). The strip is narrowly confined in the discharge region of the magnetrons by means of rolls (7) which prevent it from touching the pole-pieces of the magnet or the anode on the other side of the strip. The strip is grounded as well as the remainder of the apparatus; only the anode is insulated and held at positive voltage relative to the strip. Seventy % of the energy fed to the magnetrons is used up to heat the strip. The document does not specify how the sputter-cleaned strip is vacuum-plated afterwards.
- (2) DDR-136.047 (STEINFELDE et al.) discloses a row of plasmatrons for the repeated etching of a strip moving continuously. The efficiency of the etching is sufficient to permit subsequent coating without the need to heat the strip to high temperatures. The plasmatron gas discharge devices comprise a hollow roll of non-ferromagnetic material containing a ring-gap magnet. The metal strip maintained at cathode potential travels via guide-rolls along a hollow anode located opposite said hollow roll. A gas under reduced pressure is fed into the discharge zone via a tube with calibrating valve.
- (3) EP-A-270.144 (N.V. BEKAERT) discloses an apparatus for the continuous sputter-etching of elongated substrates such as wires, strips, cords, and the like, before coating. In this apparatus, the elongated substrate is guided through a thin anode cylindrical chamber flushed by a sputtering gas at pressures of 10⁻⁴ to 10⁻⁷ Torr. A voltage of 100 - 1000 V is applied between the substrate (which is at ground potentiel) and the anode, whereby a glow discharge is established and a plasma is formed around the substrate with a current of 50-200 mA. The substrate and the sputtering gas move in opposite directions within the tube which increases the etching efficiency. Alternatively, an AC potential can be applied to the electrodes for RF-sputtering.
- (4) FR-A-2.578.176 (ELECTRICITE DE FRANCE) describes a device for etching flat substrates, e.g. continuous strips, by means of a plasma resulting from a corona discharge. This device can include a series of successive plasma generators each of which comprises a grounded plate for supporting the substrate to be etched (generally an insulating sheet or strip material) in registration with a slotted ridge-shaped anode supplied with a plasma generating gas. When energized, this arrangement produces a stream of plasma which strikes the strip to be etched at an angle near 90° or less. The plasma is generated at a potential from about 10 to 20kV and a frequency below 100 kHz.
- (5) EP-A-169.680 (VARIAN) discloses a planar magnetron etching device incorporating a movable magnetic source opposite the surface of the object to be sputter-etched. Lines of magnetic flux move over the surface to be etched thus creating a constantly changing magnetic field profile everywhere on the surface. If two surfaces must be etched simultaneously, a separate magnetic source moves in registration with the other surface. The magnetic source comprises radial magnets in a magnetically permeable ring encased in steel. The source may be mounted on a shaft driven by vanes in a flow of coolant liquid to cause excentric rotation. If reactive ion etching is desired, a reactive gas may be admixed with the plasma generating gas.
- (6) Japanese Patent Publication No. 60-052519 (TOYOTA JIDOSHA) discloses a method for the surface treatment of cast iron materials for increasing pit resistance. The method includes the steps of coating the surface of the iron with aluminum (by plasma spraying, hot dipping, vacuum deposition or the like) and remelting the Al surface layer by a high energy beam. This produces a wear-resistant surface layer on the iron material without the need of adding alloying elements to the casting.
- (7) An article by S. Schiller et al. in 2nd International Conference on Metallurgical Coatings, 28.3 (1977), San Francisco, USA, details some of the conditions for the etch-precleaning of stainless strips before coating with metals. These authors used a ring-gap plasmatron discharge of 400-700 V under 0.6-6 Pa or argon. The current density was about 100 mA/cm² and the power consumed was about 1 kW per plasmatron for a 10 cm wide strip defilading at a rate of 0.05 - 0.1 m/sec.
- Most of the techniques disclosed in the foregoing prior art which, in contrast with the more conventional hot-dip plating techniques (see for instance US-A-4,675,214 ARMCO and EP-A-176 109 (NISSHIN STEEL)) in which the stainless strips are reduced with flue gases or hydrogen before plating, involve, prior to coating, the continuous etching of a moving strip-like substrate, this being combined in a last step with a direct in-situ metal plating operation, recommend using low pressure metal vaporization coating methods for this last step.
- However, these methods are generally tedious and costly and the method of the present invention proposes, as summarized in claim 1, to directly combine magnetron plasma etching, in a first step, with dip-coating from a molten aluminium bath, in a second step.
- Many advantages result from the application of the present method including very high etching efficiency even for hard to remove oxides like chromium, well adhering aluminum films, easy control of protective film thickness and relatively low production costs due to compactness of the apparatus for achieving the method, and high production rates. The apparatus is disclosed in annexed claim 4.
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- Fig. 12 is a schematic view of an installation for the combined plasma etching of a stainless steel strip and Al hot-dipping of said strip after etching.
- Fig. 2 is an enlarged schematic view of an etching magnetron device used in the installation of Fig. 1.
- Fig. 3 is a schematic view of another embodiment for the combined plasma etching of a stainless steel strip and its subsequent off-line plating by hot-dipping into molten aluminum.
- The installation represented on Fig. 1 comprises an enclosure consisting of four successive tubular compartments 1a - 1d connected to each other by reduced diameter apertures and terminated by a
spout 2 which penetrates into abath 3 of molten aluminum 4. - A continuous
stainless strip 5 is circulated within the installation starting from a feed-spool 6 up to a take-up spool 7 at the end of the line. The strip is guided bymain rollers roll chambers 12a to 12e which also provide gas pressure isolation between compartments and from the outside. Seal-roll chambers are detailed in document EP-A-176 109 incorporated by reference. - The components 1a to 1d of the present installation are provided with input ducts 13a to 13d, respectively, and output ducts 14a to 14d, respectively. The output ducts are used in connection with one or more suitable pumps to establish a reduced pressure within the enclosure. The input ducts are used to introduce a gas at low pressure to sustain the plasmatron discharges in the compartments; this gas is usually argon. In an embodiment of the present installation, the seal-
roll chambers instance 13d, and only one output duct, for instance 14a, are still necessary to maintain the full enclosure under the required low pressure or argon and all the other input and output ducts can be suppressed as well as the reduced diameter section between the compartments; in this case, the overall shape of the enclosure along its length remains approximately constant. - Each compartment of the present enclosure 1 contains a plasmatron device 24 (individual plasmatron are given the reference numbers 24a to 24d) which is represented on an enlarged scale in fig. 2. A plasmatron device of the kind used in the present embodiment comprises a
magnet frame 15 carrying three magnets, respectively 161, 162 and 163 arranged in order of alternating polarity, so that the magnetic field created by said magnets is closed in a confinement space between the magnets and ananode 18, as represented byreference 17 on the drawing. The magnets are placed very close to the path of the circulatingstrip 5 so that the strip will circulate within theconfinement space 17 while being prevented from rubbing against the magnets by means ofrolls 19 made of a non-magnetic material, for instance bronze or austenitic steel. Theanode 18 is connected to a positive terminal of an electric generator (not shown) by a lead passing through an insulator 20 (for instance of steatite). - When the strip is at ground potential (as is the enclosure as shown in the drawing) and the
cathode 18 is at a positive voltage of a few hundred volts, for argon pressures of a few microbars, a luminescent discharge is generated in theconfinement zone 17, as shown by the darkened area in fig. 2. Therefore the strip which passes through the luminescent discharge inzone 17 is etched by the impact of the gaseous ions formed in this region.Reference 22 designates cooling passages through which coolant fluids can be passed in case refrigeration is needed. - The several successive magnetron devices housed within successive compartments 1a to 1d are identical with that represented in fig. 2, however they are arranged in successive alternate head-to-foot orientation, so that both sides of the strip can be etched as the
strip 5 progresses along its path in the enclosure. - Under operation, the
strip 5 moves along its path in the enclosure 1 and each portion thereof passes successively in thedischarge zones 17 of each successive plasmatron device 24a to 24d. Of course, if desired, the number of compartments with respective plasmatron can be more than 4, forinstance 6, 8 or more. After passing the last discharge zone, the etched strip is guided through seal-roll chamber 12e andspout 2 into the bath of molten aluminum 4, whereby it becomes coated with a film of aluminum. The coating weight (thickness) is controlled by means of a conventional wiping apparatus W or an equivalent, after which the aluminum solidifies by cooling. Then the plated strip is stored over take-up spool 7. - Under normal operation, the energy developped in the plasmatron discharge is sufficient to heat up the strip to the desired temperature before it enters the molten aluminum bath. If this heating effect is insufficient (for instance when operating under limited magnetron power output) a
supplemental heating device 21 can be used to raise the temperature of the strip to the desired value. This heating device can be for instance a thermo-electric element or a HF induction-coil element. - Fig. 3 represents schematically another apparatus for the continuous etching and subsequent immediate plating of a stainless strip.
- This apparatus consists of a double-
sided enclosure 31, made for instance of high grade steel, one side being for the entrance of unplated strip and the other side for the removal of the plated strip. The entrance side comprises a succession of reducedsize openings 32a to 32d of very narrow diameter to provide a pressure tight passage to a strip 33 supplied by aspool 34 which circulates vertically in theenclosure 31. Normally, the clearance between the strip and the edges in thepassages 32a to 32d should be in the order of a few tens of µm (e.g. 30-100 µm) to be sealingly effective. - Then, the entrance side of the enclosure comprises a series of magnetron devices 34a to 34d each of which corresponds to that illustrated in fig. 2 and comprising a
magnet unit 35a to 35d and an anode (38a to 38d). The magnet units and the corresponding anodes are in registration with the moving strip 33 exactly as disclosed in the previous embodiment so that the strip becomes etched on both sides as it progressively passes through the discharge zones generated between the strip surface (at cathode potential) and the respective anodes. - As the strip leaves the last magnetron element (35d, 38d) it passes over a turning
roller 39 which is partly immersed in amolten aluminum bath 40, this bath being replenished as necessary with molten metal by syphoningmeans 41 represented schematically by areservoir 42 of molten aluminum and abent tube 43, the molten metal ofreservoir 42 being raised to the level of thebath 40 by the atmospheric pressure working against the reduced pressure of argon within theenclosure 31; therefore the level of molten metal ofbath 40 is maintained under control. - After being plated with Al by its passage in
bath 40, the coating weight being conventionally controlled by wiping (see W in the drawing) thestrip 5 leaves the enclosure through gas sealed passage means 44a to 44d which are of similar cons truction as theaforementioned passages 32a to 32d, and is stored over a take-upspool 45. - The
enclosure 31 is provided with a series of opening ducts referenced P₁, P₂, P₃, P₄ and Ar. The P labelled ducts are for build up of progressively reduced pressure within the enclosure, i.e. they are connected to respective vacuum pumps (not represented), while duct labelled Ar is for the arrival of a plasma sustaining gas, usually argon. - The operation of this apparatus practically duplicates that of the previous embodiment. The strip supplied by the
feed spool 34 penetrates into the enclosure through the successive gastight openings 32a to 32d; it gets etched by passing through the discharge zones in theplasmatron devices 35a - 38a to 35d - 38d; and then it is plated with aluminum by passing throughbath 40 and, finally, it exists from the enclosure by passages 44a to 44d and is stored over take-upspool 45. - The following example illustrates the invention in detail.
- An apparatus of the kind illustrated in fig. 3 was used. The strip was a 0.5 mm thick and 1 m wide stainless strip; therefore the width of each magnetron (10 units) was in correspondence. The distance between the strip and the magnet elements was set to 8 mm (see rolls 19 in fig. 1) and the discharge confinement zone between the strip and the anodes 38 (made of tantalum) was 25 mm thick 2 x 3 cm high (surface about 600 cm² for each magnetron). The magnets were made of samarium-cobalt alloy giving a magnetic field of intensity oersted in the working surface.
- The pumps connected to outputs P₁ to P₄ gave, respectively, 10, 10⁻¹, 10⁻³ and 10⁻⁵ mbar and the Argon input was adjusted to give about 3-5
x 10⁻³ mbar argon pressure in the discharge areas. The molten aluminum was maintained at 640-680°C. The strip was grounded throught the enclosure and under 500-600 V DC, the discharge current was about 20-40 mA/cm² which means an energy consumption of 2-5 kW per magnetron. Occasionally, preheating of the strip before entering the bath of molten aluminum was applied. - With strip delivery rates of 20-60 m/min, homogenous unpitted, well adherent Al plating of 3-100 µm thick were recorded.
Claims (9)
a) an elongated vacuum enclosure swept by argon under about 10⁻⁴ - 10⁻² mbar of pressure provided with gastight means for feeding and circulating unplated strip throughout the enclosure.
b) a bath of molten aluminum means for continuously circulating the strip therein and removing it afterward, so that the strip is dipped into the molten aluminum and a layer thereof is coated on the strip surface and solidifies by cooling upon withdrawal from the bath;
c) a plurality of reciprocally acting plasma magnetron etching devices alternatively placed, in succession in the enclosure along the moving strip and on both sides thereof, each of said devices comprising
i) a magnet element on one side of the strip and, in registration therewith,
ii) a counter-electrode on the other side of the strip, and
iii) means to apply a positive voltage thereto relative to the strip to generate a low pressure argon plasma discharge which will be concentrated by the magnetic field of the magnet element to at least one confinement zone between the strip and said counter-electrode,
the whole arrangement being so that both sides of the displacing strip are progressively and controllably etched by the plasma in the confinement zones of the successive etching devices before the strip enters the molten aluminum bath, thus assuring optimalized cleaning of the strip and optimalized wetting and adhesion of the coating metal on the steel surface.
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP89810362A EP0397952B1 (en) | 1989-05-18 | 1989-05-18 | A method and apparatus for the continuous etching and aluminum plating of stainless steel strips |
DE68917588T DE68917588T2 (en) | 1989-05-18 | 1989-05-18 | Method and device for the continuous etching and coating of stainless steel strips with aluminum. |
CA002016893A CA2016893C (en) | 1989-05-18 | 1990-05-16 | Apparatus for the continuous etching and aluminum plating of stainless steel strips |
JP2127039A JP2825931B2 (en) | 1989-05-18 | 1990-05-18 | Continuous etching of stainless steel strip and aluminum plating method and apparatus therefor |
US07/842,763 US5262033A (en) | 1989-05-18 | 1992-03-02 | Apparatus for the continuous etchings and aluminum plating of stainless steel strips |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP89810362A EP0397952B1 (en) | 1989-05-18 | 1989-05-18 | A method and apparatus for the continuous etching and aluminum plating of stainless steel strips |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0397952A1 true EP0397952A1 (en) | 1990-11-22 |
EP0397952B1 EP0397952B1 (en) | 1994-08-17 |
Family
ID=8203148
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP89810362A Expired - Lifetime EP0397952B1 (en) | 1989-05-18 | 1989-05-18 | A method and apparatus for the continuous etching and aluminum plating of stainless steel strips |
Country Status (4)
Country | Link |
---|---|
EP (1) | EP0397952B1 (en) |
JP (1) | JP2825931B2 (en) |
CA (1) | CA2016893C (en) |
DE (1) | DE68917588T2 (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04198465A (en) * | 1990-11-29 | 1992-07-17 | Nkk Corp | Continuous pretreatment for strip |
EP0506304A1 (en) * | 1991-03-26 | 1992-09-30 | Nisshin Steel Co., Ltd. | Method and apparatus for hot-dipping steel strip |
EP0535568A1 (en) * | 1991-09-30 | 1993-04-07 | Chugai Ro Co., Ltd. | Metal strip surface cleaning apparatus |
EP0584364A1 (en) * | 1992-02-12 | 1994-03-02 | Nisshin Steel Co., Ltd. | Al-Si-Cr-PLATED STEEL SHEET EXCELLENT IN CORROSION RESISTANCE AND PRODUCTION THEREOF |
EP0879897B2 (en) † | 1997-02-11 | 2006-08-02 | ARCELOR France | Process for continuous annealing of metal substrates |
EP1814678B2 (en) † | 2005-03-17 | 2014-08-27 | SMS Siemag AG | Method and device for descaling a metal strip |
WO2018104298A1 (en) * | 2016-12-05 | 2018-06-14 | Onderzoekscentrum Voor Aanwending Van Staal N.V. | Method and system for manufacturing a steel product having a coating with spangles, and a steel product having a coating with spangles. |
CN110519976A (en) * | 2019-08-08 | 2019-11-29 | 湖北久之洋红外系统股份有限公司 | A kind of sapphire optical window and preparation method with electro-magnetic screen function |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100489269B1 (en) * | 2002-11-18 | 2005-05-11 | 포항강판 주식회사 | Aluminum coating system for stainless steel plate and method for coating thereof |
KR101372624B1 (en) * | 2006-12-27 | 2014-03-10 | 주식회사 포스코 | Method for producing hot-dip aluminized stainless steel sheet using atmospheric pressure plasma |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE136047C (en) * | ||||
DE665540C (en) * | 1931-07-26 | 1938-09-28 | Siemens Schuckertwerke Akt Ges | Manufacture of metallic coatings on metal bodies |
GB926619A (en) * | 1960-02-17 | 1963-05-22 | Continental Can Company Ic | Improvements in or relating to coatings |
GB1536523A (en) * | 1964-03-19 | 1978-12-20 | Centre Rech Metallurgique | Production of galvanized steel strip |
EP0134143A1 (en) * | 1983-08-17 | 1985-03-13 | Nippon Steel Corporation | Hot dip aluminum coating method |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR1450637A (en) * | 1964-07-02 | 1966-06-24 | Process for obtaining metallic coatings, apparatus for carrying out said process and products in accordance with those obtained by the present process or similar process | |
US3468695A (en) * | 1964-07-02 | 1969-09-23 | Alfred P Federman | Method of coating a steel base with aluminum |
US3779056A (en) * | 1971-12-28 | 1973-12-18 | Bethlehem Steel Corp | Method of coating steel wire with aluminum |
CH648601A5 (en) * | 1979-07-31 | 1985-03-29 | Battelle Memorial Institute | METHOD OF CONTINUOUSLY COATING A METAL SUBSTRATE ON AT LEAST ONE OF ITS SURFACE WITH ANOTHER METAL AND DEVICE FOR CARRYING OUT SAID METHOD. |
US4883723A (en) * | 1986-05-20 | 1989-11-28 | Armco Inc. | Hot dip aluminum coated chromium alloy steel |
-
1989
- 1989-05-18 EP EP89810362A patent/EP0397952B1/en not_active Expired - Lifetime
- 1989-05-18 DE DE68917588T patent/DE68917588T2/en not_active Expired - Fee Related
-
1990
- 1990-05-16 CA CA002016893A patent/CA2016893C/en not_active Expired - Fee Related
- 1990-05-18 JP JP2127039A patent/JP2825931B2/en not_active Expired - Lifetime
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE136047C (en) * | ||||
DE665540C (en) * | 1931-07-26 | 1938-09-28 | Siemens Schuckertwerke Akt Ges | Manufacture of metallic coatings on metal bodies |
GB926619A (en) * | 1960-02-17 | 1963-05-22 | Continental Can Company Ic | Improvements in or relating to coatings |
GB1536523A (en) * | 1964-03-19 | 1978-12-20 | Centre Rech Metallurgique | Production of galvanized steel strip |
EP0134143A1 (en) * | 1983-08-17 | 1985-03-13 | Nippon Steel Corporation | Hot dip aluminum coating method |
Cited By (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0774424B2 (en) * | 1990-11-29 | 1995-08-09 | 日本鋼管株式会社 | Continuous pretreatment method for metal strip |
JPH04198465A (en) * | 1990-11-29 | 1992-07-17 | Nkk Corp | Continuous pretreatment for strip |
EP0506304A1 (en) * | 1991-03-26 | 1992-09-30 | Nisshin Steel Co., Ltd. | Method and apparatus for hot-dipping steel strip |
AU650104B2 (en) * | 1991-03-26 | 1994-06-09 | Nisshin Steel Company, Ltd. | Method and apparatus for hot-dipping steel strip |
EP0535568A1 (en) * | 1991-09-30 | 1993-04-07 | Chugai Ro Co., Ltd. | Metal strip surface cleaning apparatus |
EP0584364A1 (en) * | 1992-02-12 | 1994-03-02 | Nisshin Steel Co., Ltd. | Al-Si-Cr-PLATED STEEL SHEET EXCELLENT IN CORROSION RESISTANCE AND PRODUCTION THEREOF |
EP0584364A4 (en) * | 1992-02-12 | 1994-08-17 | Nisshin Steel Co Ltd | Al-si-cr-plated steel sheet excellent in corrosion resistance and production thereof |
EP0879897B2 (en) † | 1997-02-11 | 2006-08-02 | ARCELOR France | Process for continuous annealing of metal substrates |
EP1814678B2 (en) † | 2005-03-17 | 2014-08-27 | SMS Siemag AG | Method and device for descaling a metal strip |
WO2018104298A1 (en) * | 2016-12-05 | 2018-06-14 | Onderzoekscentrum Voor Aanwending Van Staal N.V. | Method and system for manufacturing a steel product having a coating with spangles, and a steel product having a coating with spangles. |
NL2017925B1 (en) * | 2016-12-05 | 2018-06-18 | Onderzoekscentrum Voor Aanwending Van Staal N V | Method and system for manufacturing a steel product having a coating with spangles, and a steel product having a coating with spangles |
CN110519976A (en) * | 2019-08-08 | 2019-11-29 | 湖北久之洋红外系统股份有限公司 | A kind of sapphire optical window and preparation method with electro-magnetic screen function |
CN110519976B (en) * | 2019-08-08 | 2020-05-22 | 湖北久之洋红外系统股份有限公司 | Sapphire optical window with electromagnetic shielding function and preparation method |
Also Published As
Publication number | Publication date |
---|---|
DE68917588T2 (en) | 1995-01-19 |
CA2016893C (en) | 2000-01-04 |
CA2016893A1 (en) | 1990-11-18 |
JPH0364442A (en) | 1991-03-19 |
JP2825931B2 (en) | 1998-11-18 |
DE68917588D1 (en) | 1994-09-22 |
EP0397952B1 (en) | 1994-08-17 |
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