EP1497055B9 - Coulage d'une bande d'acier - Google Patents
Coulage d'une bande d'acier Download PDFInfo
- Publication number
- EP1497055B9 EP1497055B9 EP03746737A EP03746737A EP1497055B9 EP 1497055 B9 EP1497055 B9 EP 1497055B9 EP 03746737 A EP03746737 A EP 03746737A EP 03746737 A EP03746737 A EP 03746737A EP 1497055 B9 EP1497055 B9 EP 1497055B9
- Authority
- EP
- European Patent Office
- Prior art keywords
- enclosure
- strip
- casting
- rolls
- water
- 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.)
- Expired - Lifetime
Links
- 238000005266 casting Methods 0.000 title claims description 100
- 229910000831 Steel Inorganic materials 0.000 title claims description 39
- 239000010959 steel Substances 0.000 title claims description 39
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 84
- 239000003595 mist Substances 0.000 claims description 47
- 239000007921 spray Substances 0.000 claims description 43
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 34
- 239000007788 liquid Substances 0.000 claims description 24
- 239000007789 gas Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 20
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 17
- 239000001301 oxygen Substances 0.000 claims description 17
- 229910052760 oxygen Inorganic materials 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 14
- 239000012298 atmosphere Substances 0.000 claims description 11
- 238000007789 sealing Methods 0.000 claims description 11
- 238000005098 hot rolling Methods 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 10
- 230000003647 oxidation Effects 0.000 claims description 8
- 238000007254 oxidation reaction Methods 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- 229910000968 Chilled casting Inorganic materials 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 5
- 239000011261 inert gas Substances 0.000 claims description 5
- 239000003380 propellant Substances 0.000 claims description 5
- 229910001208 Crucible steel Inorganic materials 0.000 claims description 4
- 238000005507 spraying Methods 0.000 claims description 3
- 238000010926 purge Methods 0.000 claims 2
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims 1
- 238000005096 rolling process Methods 0.000 description 18
- 238000009434 installation Methods 0.000 description 8
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 6
- 230000001590 oxidative effect Effects 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000010791 quenching Methods 0.000 description 4
- 230000000171 quenching effect Effects 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 3
- 238000004320 controlled atmosphere Methods 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- 239000011449 brick Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 239000000919 ceramic Substances 0.000 description 2
- 238000009749 continuous casting Methods 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 230000001464 adherent effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000005499 meniscus Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
- B22D11/0637—Accessories therefor
- B22D11/0697—Accessories therefor for casting in a protected atmosphere
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/12—Accessories for subsequent treating or working cast stock in situ
- B22D11/128—Accessories for subsequent treating or working cast stock in situ for removing
- B22D11/1287—Rolls; Lubricating, cooling or heating rolls while in use
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/16—Controlling or regulating processes or operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
- B22D15/005—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of rolls, wheels or the like
Definitions
- This invention relates to continuous casting of steel strip in a strip caster, particularly a twin roll caster.
- molten metal is introduced between a pair of counter-rotated horizontal casting rolls which are internally cooled so that metal shells solidify on the moving roll surfaces and are brought together at the nip between them to produce a solidified strip product delivered downwardly from the nip.
- the term "nip" is used herein to refer to the general region at which the casting rolls are closest together.
- the molten metal may be poured from a ladle into a smaller vessel from which molten metal flows through a metal delivery nozzle located above the nip, forming a casting pool of molten metal supported on the casting surfaces of the rolls immediately above the nip and extending along the length of the nip.
- This casting pool is usually confined between side plates or dams held in sliding engagement with end surfaces of the casting rolls to dam the two ends of the casting pool against outflow, although alternative means such as electromagnetic barriers have also been proposed.
- the strip When casting steel strip in a twin roll caster, the strip leaves the nip at very high temperatures of the order of 1400°C and can suffer very rapid scaling due to oxidation at such high temperatures. Such scaling may result in a significant loss of steel product. For example, 3% of a 1.55 mm thick strip (typical scale thickness 23 microns) can be lost from oxidation as the strip cools. Moreover, such scaling results in the need to descale the strip prior to further processing by pickling to avoid surface quality problems such as rolled-in scale, and causes significant extra complexity, cost and environmental concerns.
- the hot strip material may be passed directly to a rolling mill in line with the strip caster and thence to a run out table on which it is cooled to coiling temperature before it is coiled.
- a controlled atmosphere or atmospheres is maintained in order to inhibit oxidation of the cast strip.
- the controlled atmosphere can be produced by charging the sealed enclosure or successive enclosures with non-oxidizing gases.
- gases can be inert gases such as nitrogen or argon or exhaust gases from fuel burners.
- United States Patent 5,762,126 discloses an alternative relatively cheap and energy efficient way of limiting exposure of the high temperature strip to oxygen.
- the strip is caused to pass through an enclosure where oxygen is extracted from the atmosphere by the formation of scale.
- the enclosure is substantially sealed so as to control the ingress of oxygen into the enclosure atmosphere and control the extent of scale formation. In this method of operation, it is possible to rapidly reach a steady state condition in which scale formation is brought to low levels without the need to deliver a non-oxidizing or reducing gas into the enclosure.
- U. S. Patent 5,816,311 discloses a way of controlling the extent of scale formation by providing downstream a chamber where groups of nozzles spray a quenching medium onto the strip.
- the quenching medium was a methyl alcohol, water, or mixture of methyl alcohol and another quenching medium liquid at room temperature. It was expected that water spraying in a nitrogen atmosphere would lead to unacceptable levels of oxidation as water contains dissolved oxygen and the breakdown of water (steam) to oxygen and hydrogen would provide further oxidation; however, it was surprisingly and unexpectedly found as described in the'311 patent that it was possible to limit the thickness of oxide on the strip to no more than 0.5 microns. Additionally, it was surprisingly found that these levels of oxide were tolerable for cold rolling without pickling and then metal coating of the strip. This quenching of the steel strip was found, however, to result in uneven cooling of the steel strip introducing stresses and other defects in the strip.
- International Patent Application PCT/AU00/01478 discloses how a substantially non-oxidizing atmosphere can be cheaply and effectively produced within a downstream enclosure, through which the hot cast steel strip passes, by introducing water in a fine mist spray to generate steam within the enclosure.
- the stream generation increases the gaseous volume within the enclosure so as to produce a positive pressure in the enclosure which substantially prevents the ingress of atmospheric air. It can also produce an increased level of hydrogen gas within the enclosure to significantly reduce the oxygen level in the enclosure and reduce the rate of oxidation of the strip.
- it was considered necessary to isolate the enclosure in which steam is generated from the enclosure to which the casting rolls are exposed so as to avoid the risk of exposure of the casting pool to water or steam.
- the present invention provides a method of continuously casting steel comprising:
- a "fine mist” herein is a water spray where, in general, the water evaporates and is converted to steam before reaching the surface of the strip. There may still be the odd water droplets that reach the strip, but the intention is to avoid contact of the liquid water with the strip. Too much liquid water on the strip can cause uneven cooling of the strip.
- the precise droplet size and range of sizes of the water in the fine mist will be dependent on the temperature of the strip in the enclosure where the fine mist is sprayed, and the location of the spray nozzles within the enclosure and their distance from the strip. Notably, the location in relation to the droplet size and range is sensitive where the fine mist is sprayed in the first enclosure to avoid contact of the liquid water with the casting surfaces of the casting roll or rolls.
- the droplet size and range of the fine mist should be selected for the particular embodiment according to the geometry to provide flexibility in operation, and for the generation hydrogen gas while avoiding contact of the liquid water with the strip and the casting surfaces.
- the step of introducing water in the form of fine mist to generate steam also produces a positive pressure in the enclosure where it is introduced, namely, either the first enclosure and the second enclosure.
- the first and second enclosures are directly interconnected or spaced from each other by one or second enclosures are directly interconnected or spaced from each other by one or more chambers, with a passageway therebetween, through which gas can flow from the second enclosure to the first enclosure.
- This passageway may be the same or a different passageway from the passageway through which the cast strip moves from the first enclosure to the second enclosure.
- the sealing of the first enclosure and/or the second enclosures need not be complete, but only sufficient to provide a positive atmosphere within the first enclosure, and if present the second enclosure, with a reduced level of oxygen and an increased level of hydrogen gas in relation to the external atmosphere.
- water may in addition be introduced into the first enclosure in form of a fine mist to generate steam therein and to increase the level of hydrogen gas therein while tending to avoid liquid water contact with the steel strip and the chilled casting surfaces of the casting roll or rolls.
- the first enclosure and the second enclosure may be separately sealed against ingress of atmospheric air, and water may be introduced into the first enclosure in form of a fine mist to produce an increased level of hydrogen gas therein while tending to avoid liquid water contact with the steel strip and the casting surfaces of the casting roll or rolls.
- water introduced as a fine mist also generates steam within the first enclosure to produce a positive pressure therein and avoid egress of atmospheric air into the first enclosure.
- water may additionally be introduced into the second enclosure in form of a fine mist to produce an increased level of hydrogen gas and/or to generate steam producing a positive pressure therein, while tending to avoid liquid water contact with the steel strip.
- the cast strip may be guided through the first enclosure and into the second enclosure on a transit path through said connecting passageway.
- the strip may be guided from the first enclosure into the second enclosure along a transit path through a second passageway and/or through a connecting chamber or chambers separated from said first passageway through which gas flows between the enclosures.
- the invention further provides apparatus for casting steel strip comprising:
- the fine mist water spray further may generate steam within one or both of the first and second enclosures.
- the apparatus for casting steel strip also may have strip guides to guide the strip delivered downwardly from the nip through a transit path in the first enclosure and through a transit path in the second enclosure.
- the first enclosure and the second enclosure may be interconnected by a connecting passageway capable of permitting flow of gas therebetween, and the water sprays may comprise one or more water spray nozzles mounted in the second enclosure operable to spray a fine mist into that enclosure adjacent the steel strip while tending to avoid liquid water from contacting the steel strip, to generate steam and increase the level of hydrogen gas in both enclosures.
- the cast steel strip may be delivered to a hot rolling mill in which it is hot rolled as it is produced.
- the strip may exit the second enclosure before entering the rolling mill, and in this embodiment, may comprise a pair of mill rolls between which the strip passes to exit the second enclosure.
- the strip may remain within the second enclosure as it enters into the rolling mill, or the rolling mill may be positioned between the first and second enclosures. This positioning of the rolling mill may be achieved by sealing the second enclosure against mill rolls or a housing of the rolling mill.
- the casting and rolling installation illustrated in Figs. 1 to 7 comprises a twin roll caster denoted generally as 11 that produces a cast steel strip 12 which passes in a transit path 10 across a guide table 13 to a pinch roll stand 14. After exiting the pinch roll stand 14, the strip passes to a hot rolling mill 16 in which it is hot rolled to reduce its thickness. The rolled strip exits the rolling mill and passes to a run out table 17 on which it may be force cooled by a fine mist from water jets 18 and thence to a coiler 19.
- Twin roll caster 11 comprises a main machine frame 21 which supports a pair of parallel casting rolls 22 having casting surfaces 22A.
- Molten metal is supplied during a casting operation from a ladle 23 through a refractory ladle outlet shroud 24 to a tundish 25 and thence through a metal delivery nozzle 26 above the nip 27 between the casting rolls 22.
- Molten metal thus delivered forms a casting pool 30 supported on the casting surface 22A of the casting rolls 22.
- This casting pool 30 is confined at the ends of the rolls by a pair of side closure dams or plates 28 which are applied to stepped ends of the rolls by a pair of thrusters 31 comprising hydraulic cylinder units 32 connected to side plate holders 28A.
- the upper surface of casting pool 30 (generally referred to as the meniscus level) may rise above the lower end of the delivery nozzle 26 so that the lower end of the delivery nozzle is immersed within this casting pool.
- Casting rolls 22 are internally water cooled so that metal shells solidify on the moving casting surfaces of the casting rolls and are brought together at the nip 27 between the rolls to produce the cast strip 12, which is delivered downwardly from the nip between the rolls.
- a short length of imperfect strip is produced as the casting conditions stabilize.
- the casting rolls are moved apart slightly and then brought together again to cause this leading end of the strip to break away in the manner described in Australian Patent Application 27036/92 so as to form a clean head end of the following cast strip.
- the imperfect material drops into a scrap box 33 located beneath caster 11, and at this time, a swinging apron 34, which normally hangs downwardly from a pivot to one side of the caster outlet, is swung across the caster outlet to guide the clean end of the cast strip onto the guide table 13 from where it is fed to the pinch roll stand 14.
- Apron 34 is then retracted back to its hanging position to allow the strip 12 to hang in a loop beneath the caster before it passes to the guide table 13 where it engages a succession of guide rollers 36.
- twin roll caster may be of the kind which is illustrated and described in some detail in granted Australian Patents 631728 and 637548 and United States Patents- 5,184,668 and 5,277,243 and reference may be made to those patents for appropriate constructional details which form no part of the present invention.
- First enclosure 37 is formed by a number of separate wall sections which fit together at various seal connections to form a continuous enclosure wall.
- the enclosure 37 is comprised of a wall section 41 which is formed at the twin roll caster to enclose the casting rolls, and an enclosure wall 42, which may extend downwardly beneath wall section 41, to engage the upper edges of scrap box 33 when the scrap box is in its operative position.
- the scrap box and enclosure wall 42 may be connected by a seal 43 formed by a ceramic fiber rope fitted into a groove in the upper edge of the scrap box and engaging flat sealing gasket 44 fitted to the lower end of wall section 42.
- Scrap box 33 may be mounted on a carriage 45 fitted with wheels 46 which run on rails 47 whereby the scrap box can be moved after a casting operation to a scrap discharge position.
- Screw jack units 40 are operable to lift the scrap box from carriage 45 when it is in the operative position so that it is pushed against the enclosure wall 42 and compresses the seal 43. After a casting operation the jack units 40 are released to lower the scrap box onto carriage 45 to enable it to be moved to the scrap discharge position.
- First enclosure 37 further comprises a wall section 48 disposed about the guide table 13 and connected to the frame 49 of pinch roll stand 14 which includes a pair of pinch rolls 50 against which enclosure 37 is sealed by sliding seals 60. Accordingly, the strip exits the first enclosure 37 by passing between the pair of pinch rolls 50 and passes into a second enclosure denoted generally as 61 through which the strip passes to the hot rolling mill 16..
- Most of the first enclosure wall sections may be lined with fire brick and the scrap box 33 may be lined either with fire brick or with a castable refractory lining. Alternatively, all or parts of the first enclosure wall sections may be formed by internally water cooled metal panels.
- the enclosure wall section 41 which surrounds the casting rolls is formed with side plates 51 provided with notches 52 shaped to snugly receive the side dam plate holders 28A when the side dam plates 28 are pressed against the ends of the rolls by the cylinder units 32.
- the interfaces between the side plate holders 28A and the enclosure side wall sections 51 are sealed by sliding seals 53 to maintain sealing of first enclosure 37.
- Seals 53 may be formed of ceramic fiber rope.
- the cylinder units 32 extend outwardly through the enclosure section 41 and at these locations first enclosure 37 is sealed by sealing plates 54 fitted to the cylinder units so as to engage with the enclosure wall section 41 when the cylinder units are actuated to press the side plates against the ends of the rolls. Thrusters 31 also move refractory slides 55 which are moved by the actuation of the cylinder units 32 to close slots 56 in the top of first enclosure 37 through which the side plates are initially inserted into the enclosure and into the holders 28A for application to the rolls. The top of first enclosure 37 is closed by the tundish, the side plate holders 28A and the slides 55 when the cylinder units are actuated to apply the side dam plates against the rolls. In this way the complete enclosure 37 is sealed prior to a casting operation to establish the sealed space 38 adjacent the casting surfaces 22A of casting rolls 22.
- the second enclosure 61 may be separate from the first enclosure 37, where the strip can be held in a separate atmosphere in second enclosure 61 up to the hot rolling mill 16.
- Rolling mill 16 contains a series of pass line rollers 62 to guide strip horizontally through second enclosure 61 to the work rolls 63 of rolling mill 16 which are disposed between two larger backing rolls 64.
- Second enclosure 61 is sealed at one end against pinch rolls 50 by sliding seals 65, and at the other end, it is sealed against the working rolls 63 of rolling mill 16 by sliding seals 66.
- the sliding seals 65 and 66 could be replaced by rotary sealing rolls to run or the strip in the vicinity of the pinch rolls and reduction rolls, respectively.
- Second enclosure 61 is fitted with a pair of water spray nozzles 67 and 68 that are each operable to spray a fine mist of water droplets adjacent the surface of the steel strip as it passes through the second enclosure, and thereby to generate steam within the second enclosure while tending to avoid liquid water contact with the steel strip.
- Spray nozzle 67 is mounted in the roof of enclosure 61 downstream from the pinch roll stand 14.
- Nozzle 68 is located at the other end of enclosure 61 in advance of the rolling mill 16.
- the nozzles 67 and 68 may be standard commercially available mist spray nozzles operable with a gas propellant to produce a fine mist of water.
- the gas propellant may be an inert gas such as nitrogen.
- the nozzles will be operated under nitrogen at a pressure of around 400 kPa.
- the water may be supplied at around 100-500 kPa pressure, although the pressure of the water is not critical.
- the nozzles are set up to produce a fine mist spray across the width of the strip to generate steam within the second enclosure 61.
- both of first enclosure 37 and second enclosure 61 may initially be purged with nitrogen gas prior to commencement of casting.
- the water sprays Prior to casting, the water sprays are activated so that as soon as the hot strip passes into second enclosure 61 steam is generated within that enclosure so as to produce a positive pressure preventing ingress of atmospheric air.
- the supply of nitrogen may be terminated after commencement of casting.
- the cast strip will take up all of the oxygen from the first enclosure 37 to form heavy scale on the strip.
- the sealing of space 38 of first enclosure 37 controls the ingress of oxygen containing atmosphere below the amount where substantial amounts of oxygen are taken up by the steel strip.
- the oxygen content in the first enclosure 37 will remain depleted and limiting the availability of oxygen for oxidizing of the strip. In this way, the formation of scale on the cast strip is controlled without the need to maintain a supply of nitrogen to space 38 of the first enclosure 37.
- pinch roll 14 is provided with sliding seals 60, 65 to slide on the pinch rolls 50 at the division between first and second enclosures 38 and 61.
- the pinch rolls and seals are effective to prevent a back flow of liquid water from second enclosure 61 but pinch roll stand 14 provides a gas flow passageway around the two ends of the pinch rolls 50 by which gas can flow from the second enclosure 61 to the first enclosure 38. It has been found in operation of the apparatus that the intercommunication between the two enclosures by this interconnecting passageway is quite sufficient to permit increased levels of hydrogen to flow from the second enclosure 61 into the first enclosure 37. This is shown by the following results obtained by operation of a twin roll casting and rolling installation as illustrated in the drawings and testing with and without the operation of the fine mist water sprays 67 and 68.
- the levels hydrogen within the first enclosure 37 are still increased substantially by operation of the fine mist water nozzles in the second enclosure 61.
- the increased levels of hydrogen in both the first and second enclosures 37, 61 are associated with a marked reduction in oxygen content and dramatically reduce scale formation.
- there are elevated humidity levels in both the first and second enclosures indicating the presence of steam, and both enclosures are under positive pressure by the presence of steam.
- the increased hydrogen level may be explained by catalytic reaction of water molecules in the fine mist under the high temperature conditions surrounding the steel strip within the second enclosure to form hydrogen gas.
- Oxygen gas simultaneously formed from water molecules is taken up by oxidizing of the strip during initial passage of the strip through the second enclosure, so that a substantial quantity of hydrogen gas is generated. Subsequent oxidation of the strip is suppressed by the hydrogen gas and the positive pressure within the second enclosure which limits ingress of atmospheric air, but is sufficient to maintain the hydrogen content in the second enclosure and to produce a very thin layer of scale on the strip which has been found to be desirable on hot rolling to avoid sticking in the roll bite. It has been found that the very thin layer of scale produced in the extremely moist atmosphere in second enclosure 61 serves as a strongly adherent lubricant which minimizes roll wear and operational difficulties at the rolling mill. At the same time, because the fine mist spray is generated into steam in the second enclosure, contact of the steel strip with liquid water tends to be avoided and the prospect of uneven cooling of the strip is substantially reduced if not eliminated.
- Fig. 8 illustrates a modification to the casting and rolling installation by which additional water spray nozzles 71, 72 are arranged to generate a fine water mist spray in the first enclosure 37. Apart these additional spray nozzles, the installation illustrated in Fig. 8 is the same as previously described. Accordingly, the other components have been identified in Fig. 8 by the same reference numerals as in Fig. 1 .
- Spray nozzles 71, 72 are similar to the nozzles 67, 68 and may be operated in similar fashion and under the same conditions to spray a fine water mist adjacent the surface of strip 12 while attending to avoid liquid water contact with the strip.
- spray nozzles 71, 72 are positioned toward the exit end of enclosure 37 to minimize the possibility of liquid water coming into contact with the casting surfaces 22A of casting rolls 22.
- a curtain gate seal may be installed at a location between the spray nozzles 71, 72 and the casting rolls as indicated at 73 to further minimize this risk.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Continuous Casting (AREA)
- Metal Rolling (AREA)
Claims (25)
- Procédé de coulage d'acier en continu, comprenant les étapes consistant à :(a) former un bassin de coulée d'acier fondu sur des surfaces de coulage en coquille d'au moins un rouleau de coulée ;(b) déplacer les surfaces de coulage en coquille pour produire une bande d'acier coulé s'éloignant du bassin de coulée ;(c) guider la bande coulée à travers une première enceinte adjacente aux surfaces de coulage, et facultativement, suite à ceci, à travers une seconde enceinte, à mesure que la bande s'éloigne du bassin de coulée ; et(d) sceller la première enceinte et, si elle existe, la seconde enceinte, par rapport à l'air ambiant ; et(e) introduire de l'eau dans au moins une enceinte sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de l'enceinte tout en tendant à éviter le contact de la bande d'acier avec de l'eau à l'état liquide, caractérisé en ce que l'introduction d'eau sous forme de brume légère produit un niveau accru d'hydrogène à l'intérieur de la première chambre tout en tendant à éviter le contact de l'eau avec les surfaces de coulage du rouleau ou des rouleaux de coulée et la bande d'acier.
- Procédé selon la revendication 1, dans lequel la première et la seconde enceintes sont scellées séparément et l'eau est introduite dans la première enceinte sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de la première enceinte tout en tendant à éviter le contact de la bande d'acier et des surfaces de coulage du rouleau ou des rouleaux de coulée avec de l'eau à l'état liquide.
- Procédé selon la revendication 1, dans lequel l'eau est introduite dans la seconde enceinte sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de la seconde enceinte tout en tendant à éviter le contact de la bande d'acier avec de l'eau à l'état liquide, et comprenant de plus l'étape consistant à acheminer du gaz avec un niveau d'hydrogène accru de la seconde enceinte à la première enceinte.
- Procédé selon la revendication 1, 2 ou 3, dans lequel la bande quitte la première chambre à une température allant d'environ 1300 °C à 1150 °C.
- Procédé selon l'une quelconque des revendications 1 à 4, dans lequel afin de produire le jet de brume, l'eau est propulsée en force par un gaz propulseur à travers une ou plusieurs buses de pulvérisation de brume.
- Procédé selon la revendication 5, dans lequel le gaz propulseur est un gaz inerte.
- Procédé selon la revendication 5, dans lequel le gaz propulseur est de l'azote.
- Procédé selon l'une quelconque des revendications 1 à 7, dans lequel la bande est acheminée de la première enceinte à la seconde enceinte à travers une paire de rouleaux pinceurs.
- Procédé selon la revendication 8, dans lequel les rouleaux pinceurs sont actionnés de sorte à réduire l'épaisseur de la bande dans une proportion pouvant aller jusqu'à 5 %.
- Procédé selon l'une quelconque des revendications 1 à 9, dans lequel la première et la seconde enceintes sont initialement purgées par un gaz inerte avant le commencement du coulage de ladite bande de sorte à réduire la teneur initiale en oxygène à l'intérieur des enceintes.
- Procédé selon la revendication 10, dans lequel la purge réduit la teneur initiale en oxygène à l'intérieur de l'enceinte de 5 % à 10 % environ.
- Procédé selon la revendication 10 ou 11, dans lequel le gaz de purge est de l'azote.
- Procédé selon la revendication 10, 11 ou 12, dans lequel pendant le coulage de ladite bande, la première enceinte est chargée continuellement en gaz inerte.
- Procédé selon la revendication 10, 11 ou 12, dans lequel pendant le coulage de ladite bande, la teneur en oxygène dans la première enceinte est maintenue à un niveau inférieur à celui de l'air ambiant par oxydation continue de la bande passant à travers celle-ci.
- Procédé selon l'une quelconque des revendications 1 à 14, dans lequel la bande solidifiée est acheminée vers un laminoir à chaud, dans lequel elle est laminée à chaud à mesure que la bande est produite.
- Procédé selon la revendication 15, dans lequel le laminoir à chaud est disposé à la sortie de la seconde enceinte et il scelle ladite enceinte de manière à laminer à chaud la bande à mesure qu'elle quitte la seconde enceinte.
- Appareil de coulage d'acier, comprenant :(a) une paire de rouleaux de coulée (22) positionnés dans un sens généralement horizontal formant entre ceux-ci une zone de pincement (27) ;(b) un système de distribution de métal (23, 25) conçu pour distribuer de l'acier fondu au-dessus de la zone de pincement entre les rouleaux de coulée pour former un bassin de coulée (30) d'acier fondu supporté sur les rouleaux de coulée ;(c) un système de refroidissement pour refroidir intérieurement les rouleaux de coulée ;(d) un système d'entraînement pour entraîner en rotation inverse les rouleaux de coulée dans des directions opposées ;(e) lesdits rouleaux de coulée ayant des surfaces de coulée refroidies (22A) pour produire une bande coulée acheminée vers le bas à partir de la zone de pincement ;(f) une première enceinte (37) adjacente aux rouleaux de coulée à travers laquelle passe la bande coulée sur une voie de passage s'éloignant de la zone de pincement ;(g) facultativement, une seconde enceinte (61) à travers laquelle passe la bande coulée après que la bande coulée a traversé la première enceinte ;(h) des joints d'enceinte scellant la première enceinte et, si elle existe, la seconde enceinte ; et(i) au moins un jet d'eau (67, 68, 71, 72) actionnable pour pulvériser de l'eau sous forme de brume légère dans au moins une enceinte pour produire un niveau accru d'hydrogène gazeux dans l'enceinte tout en tendant à éviter le contact de la bande d'acier avec de l'eau à l'état liquide, caractérisé en ce que ledit au moins un jet d'eau est actionnable pour pulvériser de l'eau sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de la première enceinte (37) tout en tendant à éviter le contact des rouleaux de coulée avec de l'eau à l'état liquide.
- Appareil selon la revendication 17, dans lequel la première enceinte (37) et, si elle existe, la seconde enceinte (61) sont scellées séparément, et le jet d'eau (71, 72) est apte à pulvériser de l'eau dans la première enceinte (37) sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de la première enceinte tout en tendant à éviter le contact de la bande d'acier et des rouleaux de coulée (22) avec de l'eau à l'état liquide.
- Appareil selon la revendication 17, dans lequel le jet d'eau est apte à pulvériser de l'eau dans la seconde enceinte (61) sous forme de brume légère pour produire un niveau accru d'hydrogène gazeux à l'intérieur de la seconde enceinte tout en tendant à éviter le contact de la bande d'acier avec de l'eau à l'état liquide, et la première enceinte (37) ainsi que la seconde enceinte (61) sont scellées avec un passage d'interconnexion entre les enceintes pour permettre au gaz de circuler de la seconde enceinte à la première enceinte afin de produire un niveau accru d'hydrogène gazeux à l'intérieur de la première enceinte.
- Appareil selon la revendication 17, 18 ou 19, comprenant de plus des guides de bande (13, 62) pour guider la bande acheminée vers le bas depuis la zone de pincement à travers une voie de passage (10) dans la première enceinte (37) et à travers une voie de passage dans la seconde enceinte (61), si la seconde enceinte existe.
- Appareil selon l'une quelconque des revendications 17 à 20, dans lequel ledit au moins un jet (67, 68, 71, 72) est disposé de sorte à pulvériser une brume d'eau vers une face supérieure de la bande d'acier.
- Appareil selon l'une quelconque des revendications 17 à 21, dans lequel la première et la seconde enceintes (37, 61) sont séparées l'une de l'autre par une paire de rouleaux pinceurs (50).
- Appareil selon la revendication 22, dans lequel les rouleaux pinceurs (50) sont actionnables pour réduire l'épaisseur de la bande.
- Appareil selon l'une quelconque des revendications 17 à 23, comprenant en outre un laminoir à chaud (16) disposé de sorte à laminer à chaud la bande à mesure qu'elle est produite.
- Appareil selon la revendication 24, dans lequel le laminoir à chaud (16) est disposé à la sortie de la seconde enceinte (61) et scelle cette enceinte de sorte à laminer à chaud la bande à mesure qu'elle quitte la seconde enceinte.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/121,567 US6776218B2 (en) | 1999-11-30 | 2002-04-12 | Casting steel strip |
US121567 | 2002-04-12 | ||
PCT/US2003/011263 WO2003086683A1 (fr) | 2002-04-12 | 2003-04-11 | Coulage d'une bande d'acier |
Publications (4)
Publication Number | Publication Date |
---|---|
EP1497055A1 EP1497055A1 (fr) | 2005-01-19 |
EP1497055A4 EP1497055A4 (fr) | 2006-04-19 |
EP1497055B1 EP1497055B1 (fr) | 2008-09-17 |
EP1497055B9 true EP1497055B9 (fr) | 2009-09-02 |
Family
ID=29248307
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03746737A Expired - Lifetime EP1497055B9 (fr) | 2002-04-12 | 2003-04-11 | Coulage d'une bande d'acier |
Country Status (9)
Country | Link |
---|---|
EP (1) | EP1497055B9 (fr) |
JP (1) | JP4373796B2 (fr) |
KR (1) | KR101029687B1 (fr) |
CN (1) | CN1309505C (fr) |
AU (1) | AU2003226348B2 (fr) |
BR (1) | BRPI0309176B1 (fr) |
CA (1) | CA2482055C (fr) |
DE (1) | DE60323618D1 (fr) |
WO (1) | WO2003086683A1 (fr) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8196641B2 (en) | 2004-11-16 | 2012-06-12 | Rti International Metals, Inc. | Continuous casting sealing method |
DE102007009678A1 (de) * | 2006-10-27 | 2008-04-30 | Sms Demag Ag | Bandschleuse |
US7984748B2 (en) | 2008-07-03 | 2011-07-26 | Nucor Corporation | Apparatus for continuous strip casting |
CN101462105B (zh) * | 2008-09-27 | 2013-09-11 | 苏州扬子江新型材料股份有限公司 | 彩色涂层钢板涂膜烘烤后的冷却系统 |
DE102009018683A1 (de) * | 2009-04-23 | 2010-10-28 | Sms Siemag Ag | Verfahren und Vorrichtung zum Stranggießen einer Bramme |
CN102828195A (zh) * | 2011-06-14 | 2012-12-19 | 辽宁科技大学 | 热轧带钢连续还原除鳞方法及其装置 |
CN102328040B (zh) * | 2011-07-12 | 2014-07-23 | 陈寅明 | 钢坯结晶的二次冷却方法及装置 |
DE102014205999A1 (de) * | 2014-03-31 | 2015-10-01 | Bayerische Motoren Werke Aktiengesellschaft | Bearbeitungsvorrichtung zum Bearbeiten eines gegossenen Gussrohteils und Verfahren zum Herstellen eines Gussbauteils |
CN109115795B (zh) * | 2018-09-06 | 2020-11-13 | 嘉兴鼎尚信息科技有限公司 | 雾化系统、使用该雾化系统的检测设备及工作方法 |
Family Cites Families (15)
Publication number | Priority date | Publication date | Assignee | Title |
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BE792303A (fr) * | 1971-06-09 | 1973-03-30 | Battelle Memorial Institute | Procede de coulee continue d'une barre de metal et dispositif pour la mise en oeuvre de ce procede |
US4000771A (en) * | 1973-07-27 | 1977-01-04 | Williamson Calvin C | Method of and apparatus for continuous casting |
DE2757694A1 (de) * | 1977-12-21 | 1979-06-28 | Mannesmann Ag | Verfahren und vorrichtung zum kuehlen des stranges beim stranggiessen von metallen |
JPS57127505A (en) * | 1981-01-22 | 1982-08-07 | Nippon Steel Corp | Direct rolling manufacturing device for steel |
JPS58202958A (ja) * | 1982-05-20 | 1983-11-26 | Kawasaki Steel Corp | 鋼の連続鋳造方法 |
JPS6277151A (ja) * | 1985-09-30 | 1987-04-09 | Nippon Steel Corp | 双ロール型連続鋳造装置 |
JPH0568525A (ja) * | 1991-09-12 | 1993-03-23 | Ajinomoto Co Inc | 立体成型食品の製造法 |
JPH06277151A (ja) * | 1993-03-30 | 1994-10-04 | Sharp Corp | 加熱調理器 |
DE69524185T2 (de) * | 1994-04-04 | 2002-05-02 | Nippon Steel Corp., Tokio/Tokyo | Zwei-walzen-giessverfahren |
TW297788B (fr) * | 1994-12-15 | 1997-02-11 | Sumitomo Metal Ind | |
AUPN101495A0 (en) * | 1995-02-10 | 1995-03-09 | Bhp Steel (Jla) Pty Limited | Casting steel strip |
RU2128717C1 (ru) | 1995-04-14 | 1999-04-10 | Ниппон Стил Корпорейшн | Устройство для производства полосы из нержавеющей стали |
AUPN733095A0 (en) * | 1995-12-22 | 1996-01-25 | Bhp Steel (Jla) Pty Limited | Twin roll continuous caster |
AUPQ436299A0 (en) * | 1999-12-01 | 1999-12-23 | Bhp Steel (Jla) Pty Limited | Casting steel strip |
JP5068525B2 (ja) * | 2006-12-28 | 2012-11-07 | 株式会社岡村製作所 | 椅子における背板の取付装置 |
-
2003
- 2003-04-11 KR KR1020047016304A patent/KR101029687B1/ko not_active IP Right Cessation
- 2003-04-11 BR BRPI0309176A patent/BRPI0309176B1/pt not_active IP Right Cessation
- 2003-04-11 CN CNB038108380A patent/CN1309505C/zh not_active Expired - Fee Related
- 2003-04-11 AU AU2003226348A patent/AU2003226348B2/en not_active Ceased
- 2003-04-11 JP JP2003583682A patent/JP4373796B2/ja not_active Expired - Fee Related
- 2003-04-11 EP EP03746737A patent/EP1497055B9/fr not_active Expired - Lifetime
- 2003-04-11 DE DE60323618T patent/DE60323618D1/de not_active Expired - Lifetime
- 2003-04-11 CA CA2482055A patent/CA2482055C/fr not_active Expired - Fee Related
- 2003-04-11 WO PCT/US2003/011263 patent/WO2003086683A1/fr active Application Filing
Also Published As
Publication number | Publication date |
---|---|
CN1309505C (zh) | 2007-04-11 |
WO2003086683A1 (fr) | 2003-10-23 |
AU2003226348B2 (en) | 2008-09-18 |
CA2482055A1 (fr) | 2003-10-23 |
EP1497055A4 (fr) | 2006-04-19 |
CA2482055C (fr) | 2011-04-05 |
AU2003226348A1 (en) | 2003-10-27 |
DE60323618D1 (de) | 2008-10-30 |
JP4373796B2 (ja) | 2009-11-25 |
KR101029687B1 (ko) | 2011-04-15 |
KR20060026837A (ko) | 2006-03-24 |
BRPI0309176B1 (pt) | 2016-10-04 |
EP1497055B1 (fr) | 2008-09-17 |
BR0309176A (pt) | 2005-01-25 |
JP2005522330A (ja) | 2005-07-28 |
CN1652886A (zh) | 2005-08-10 |
EP1497055A1 (fr) | 2005-01-19 |
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