AU4877899A - Process for manufacturing a thin stainless steel strip - Google Patents
Process for manufacturing a thin stainless steel strip Download PDFInfo
- Publication number
- AU4877899A AU4877899A AU48778/99A AU4877899A AU4877899A AU 4877899 A AU4877899 A AU 4877899A AU 48778/99 A AU48778/99 A AU 48778/99A AU 4877899 A AU4877899 A AU 4877899A AU 4877899 A AU4877899 A AU 4877899A
- Authority
- AU
- Australia
- Prior art keywords
- strip
- casting
- rolling
- stainless steel
- rolls
- 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
- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 14
- 239000010935 stainless steel Substances 0.000 title claims abstract description 10
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 7
- 238000000034 method Methods 0.000 title claims description 13
- 238000005266 casting Methods 0.000 claims abstract description 39
- 238000005098 hot rolling Methods 0.000 claims description 15
- 239000000203 mixture Substances 0.000 claims description 4
- 150000001875 compounds Chemical class 0.000 claims 1
- 238000005096 rolling process Methods 0.000 abstract description 27
- 238000007711 solidification Methods 0.000 abstract description 12
- 230000008023 solidification Effects 0.000 abstract description 12
- 239000007788 liquid Substances 0.000 abstract description 8
- 229910000831 Steel Inorganic materials 0.000 abstract description 7
- 239000010959 steel Substances 0.000 abstract description 7
- 238000009434 installation Methods 0.000 abstract 1
- 238000010030 laminating Methods 0.000 abstract 1
- 238000003475 lamination Methods 0.000 abstract 1
- 239000011148 porous material Substances 0.000 description 22
- 238000003466 welding Methods 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 230000007547 defect Effects 0.000 description 5
- 229910001338 liquidmetal Inorganic materials 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000006731 degradation reaction Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 230000008602 contraction Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 239000011572 manganese Substances 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000010405 reoxidation reaction Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000003466 anti-cipated effect Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 239000010955 niobium Substances 0.000 description 1
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/40—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling foils which present special problems, e.g. because of thinness
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/463—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a continuous process, i.e. the cast not being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/46—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting
- B21B1/466—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling metal immediately subsequent to continuous casting in a non-continuous process, i.e. the cast being cut before rolling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
- B21B3/02—Rolling special iron alloys, e.g. stainless steel
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Metal Rolling (AREA)
- Continuous Casting (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Physical Vapour Deposition (AREA)
- Chemical Vapour Deposition (AREA)
- Chemical Treatment Of Metals (AREA)
- Reduction Rolling/Reduction Stand/Operation Of Reduction Machine (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Manufacturing a thin strip of stainless steel comprises direct solidification of liquid steel in a casting installation comprising two cooled moving walls; solidification is finished when the strip leaves the walls; and hot laminating this strip using a rolling mill with cylinders having a diameter of 400-900 mm, the strip temperature after leaving the rolling mill is 800-1100 degrees C; the rate of reduction of the strip thickness during hot lamination is 15-50 %.
Description
AUSTRALIA
PATENTS ACT 1990 COMPLETE SPECIFICATION NAME OF APPLICANT(S): UGINE SA r.
cc r o o o oo r ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourne, 3000.
INVENTION TITLE: Process for manufacturing a thin stainless steel strip The following statement is a full description of this invention, including the best method of performing it known to me/us:- IP AUSTRALIA
RECEIVED
1 7 SEP 1999
MELBOURNE
la The invention relates to the manufacture of thin stainless steel strip, directly from liquid metal, by solidification within a mould consisting of two cooled walls moving at the same speed as the solidified strip, such as the external walls of two rotating rolls having horizontal axes.
In this casting process, which is under industrial-scale development and is referred to as "twin-roll casting", one of the major problems associated with the quality of the strip is the possible presence of porosity in the core of the strip.
When this porosity is found on products coming from the subsequent conversions undergone by the strip (such as pickling, annealing, cold rolling and other conversion e operations), it limits the field of application of the products because of the degradation in the mechanical properties that result from this porosity.
The causes for the appearance of this porosity in the core of twin-roll cast strip may be similar to e those which result (on a larger dimensional scale) in shrinkage cavities in the ingots and the central porosity in conventional continuous casting products, namely closure by solid metal of pockets containing still-liquid metal when the solidification of the product (which normally is substantially completed by .the time the strip leaves the walls of the mould, that is to say the core of the strip is not totally in the liquid state) does not take place completely uniformly.
The cooling and solidification of the liquid metal that these pockets contain are accompanied by contraction of this metal, which causes a void to appear. This cannot be filled before the end of solidification since this closed pocket is no longer fed with fresh liquid metal.
These pores must be distinguished from spherical defects called "blowholes" which are due to a release of dissolved gas and usually occur near the surface of the products.
2 Document EP 0,396,862 proposes a process aimed at eliminating the central porosity, and also any internal and surface defects, during the twin-roll casting of steel strip. According to this process, the casting rolls have on their surfaces precisely dimensioned circumferential grooves arranged in an offset manner on both rolls. The aim is thus to prevent the solidified metal shells on the surfaces of the rolls separating, which would result in irregularities in the solidification of the strip. However, it seems that the sole prevention of such separation is insufficient to completely prevent the appearance of central porosity.
Document JP 8252653 proposes a process in which, in line with the casting operation, the strip undergoes hot rolling under conditions satisfying the following inequality: ooe r (2.74x10- 5
T
2 -6.88x10-2T+43.55) (to/w 0 V *with: r: hot-rolling reduction ratio; T: hot-rolling temperature in C; to: pore diameter in the thickness direction of the strip; w 0 pore diameter in the width direction of S 25 the strip.
According to this process, it is therefore necessary for the hot rolling to be carried out with a reduction ratio sufficient for the pores to be closed up during this rolling, and this minimum ratio depends on the rolling temperature (that is to say the temperature at which the strip enters the roll nip) and on the shape and the orientation of the pores. However, it has been found that these rolling conditions are still insufficient for reliably closing up all the pores, and above all that they do not always prevent the closed pores from opening up again during conversion of the strip or use of the products which stem therefrom, causing them to break.
3 The objective of the invention is to propose a process guaranteeing that the central pores appearing in the core of the strip after it has fully solidified are definitely closed.
For this purpose, the subject of the invention is a process for manufacturing a thin stainless steel strip by direct solidification of the liquid steel in the form of a strip of thickness less than or equal to 8 mm in a casting plant comprising two cooled moving walls and by hot rolling the said strip, the solidification of which is substantially complete by the time it leaves the said walls, characterized in that the hot rolling is carried out on a rolling mill, the work rolls of which have a diameter of between 400 and 900 mm, in that the temperature of the strip as it leaves the rolling mill is between 800 and 1100 0 C and in that the thickness reduction ratio of the strip during hot rolling is between 15 and Preferably, the hot rolling is carried out in 20 line with the casting of the strip. The casting plant may be of the "twin-roll casting" type.
As will have been understood, the objective of the invention is achieved by the combination of requirements with regard to the diameter of the work 25 rolls of the hot-rolling mill, the temperature of the strip on leaving the rolls and the thickness reduction ratio of the strip during hot rolling.
.The invention applies to the casting of stainless steels of any class, which conventionally have carbon contents less than or equal to silicon contents less than or equal to manganese contents less than or equal to 15%, chromium contents between and 30%, copper contents less than or equal to 5% and nitrogen contents less than or equal to 0.5% (these contents are expressed as percentages by weight). These steels may also contain large amounts of nickel (up to or of molybdenum (up to Moreover, as is usually the case, other elements are present in the metal, either as impurities or as alloying elements, 4 particularly sulphur, phosphorus, titanium, niobium and zirconium. Their total content must not exceed 2% by weight.
As mentioned, a thin twin-roll cast stainless steel strip is highly likely to develop porosity in its core, during its solidification, when a liquid pocket is closed up by solid metal. This phenomenon occurs at the end of solidification of the pasty region, also called the "equiaxed region", located between the two solidified shells in contact with the rolls, which shells are also called the "columnar regions". The equiaxed region is very difficult to control, and its thickness may vary depending on the rate of solidification of the columnar regions. Thus, the equiaxed region may locally close up in the anticipated manner at the points where the growth of the columnar regions has been more rapid than normal. Downstream from the point of closure of the equiaxed region, the liquid pockets can no longer be correctly refed with liquid metal, and pores form by contraction of the metal as these liquid pockets solidify. Nevertheless, this case remains quite rare and in fact, in general, the isolation of a liquid pocket occurs by the clustering of equiaxed crystals in the liquid, which 25 form a plug obstructing the equiaxed region. The pores which form in the equiaxed region consist of groups of channels and cavities containing no gas, the maximum dimension of which, in the thickness direction of the sheet, corresponds to the thickness of the equiaxed region 100 to 400 un), which channels and cavities may be as long as 1 to 2 mm in the other directions. As mentioned, these are not spherical blowholes, which would arise by the release of gas, or internal defects emerging on the surface of the strip.
The basic idea of the invention is to create, while the solidified strip is being hot rolled, conditions such that they lead not only to closure of the central pores, as is already known, but also to veritable welding of the opposed pore walls, that the rolling has allowed to come together. In this way, it may be ensured that there will be no risk of the pores opening during subsequent forming of the strip or during use of the products thus produced. As the strip is being hot rolled, two steps occur. Firstly, the internal walls of the defect gradually come together as the thickness of the strip is reduced, until they come into contact with each other. Then, once this contact has been made, welding of the walls occurs by diffusion of the constituent elements of the steel across the interface. However, the walls must have already been effectively welded immediately before the strip leaves the roll nip of the rolling mill, otherwise the release of the compression of the strip which occurs on leaving the rolls would cause partial separation of the walls.
The effectiveness of the welding depends S. essentially on two parameters: the duration of the forced contacting of the walls in the rolling mill and V the temperature at which this contacting takes place.
20 This forced contact therefore must take place as soon as possible after the strip enters the rolling mill, and its duration mainly depends, for a given rolling speed (which, in the case of in-line rolling, is largely determined by the thickness of the strip before it is rolled), on the diameter of the work rolls of the rolling mill and its thickness reduction ratio that they impose on the strip. The larger the diameter of the rolls and the higher the reduction ratio, the more ee rapid and prolonged the forced contacting of the pore walls. However, it may not be sufficient to state that, in order for the problem posed to be solved satisfactorily, all that is required is to roll the strip with a reduction ratio and a roll diameter which are as high as possible. This is because too high a reduction ratio, which would exceed the hot deformability of the strip, leads to the appearance of surface cracks, on the strip which are absolutely to be avoided. Moreover, the temperature at which the forced contacting of the pore walls takes -6 place depends not only on the entry temperature of the strip in the rolling mill but also on the duration of the contact between the strip and the rolls, since this contact causes the strip to cool. If, for a given entry temperature of the strip, the rolls have a very large diameter, there is a risk that the cooling of the strip which they cause would take the latter to a temperature not high enough for the pore walls to be able to be fully welded. In this regard, the value of the temperature of the strip as it leaves the rolls gives a good indication of the actual possibility that the pore walls have had of being welded to each other in the roll nip.
The temperature of the strip on leaving the rolls must therefore be high enough to allow welding of the pores, but it must not be too high either, so as to avoid an excessive thermal load on the rolls. This would result in degradation of their surface, leading to a deterioration in the surface appearance of the strip in the form of excessive roughness. The objective of the invention can therefore be achieved without obtaining secondary effects adversely affecting the general quality of the strip only if the diameter of the rolls, the reduction ratio and the strip 25 temperature on leaving the rolling mill are combined in a suitable manner.
In order to determine how these parameters must be combined, series of trials were carried out, during which, for a given type of stainless steel, the diameter of the work rolls of the rolling mill, the thickness reduction ratio of the strip and the temperature of the strip on leaving the rolling mill were varied. The rolling mill was placed in line with the casting plant. Each trial involved a characterization making it possible to determine whether or not the welding of the pores had been effective. This characterization consisted in breaking a tensile test piece and examining the fracture surface. If the fracture surface exhibits pores which 7 were open during the tensile test, it may be concluded that the welding had not been satisfactory. If the fracture surface exhibits no apparent porosity, the welding is judged to have been satisfactory.
Table 1 gives the compositions of the steels on which the trials were carried out, the results of the trials being given in Table 2. The contents of the various elements are given in percentages by weight.
Table 1 also gives the thicknesses of the strips on leaving the casting rolls, on which strips the trials were carried out, as well as the corresponding casting speeds measured between the casting rolls and the hotrolling mill.
Table 1: Composition of the steels of the trial casting runs, the thickness of the cast strip and the casting rates Casting Casting Casting Casting runs A runs A' runs B runs C C 0.05 0.05 0.04 0.01 Mn 1.5 1.5 0.4 0.2 P 0.04 0.04 0.04 0.03 S 0.01 0.01 0.01 0.01 Si 0.3 0.3 0.3 Ni 8.6 8.6 0.3 0.1 Cr 18 18 16.5 11.5 Cu 0.5 0.5 0.2 0.2 Mo 0.5 0.5 0.1 0.1 Ti 0.01 0.01 0.01 0.15 N 0.05 0.05 0.04 0.01 Strip thickness 4 mm 2 mm 3 mm 3 mm Casting speed 25 m/min. 100 m/min. 60 m/min. 60 m/min.
The compositions of the type A and A' casting runs correspond to those of conventional austenitic stainless steels of the AISI 304 type. The type B casting runs correspond to ferritic stainless steels of the AISI 430 type. The type C casting runs correspond to ferritic stainless steels of the titanium-stabilized AISI 409 type.
-8 Table 2 gives the results of trials carried out on the strip resulting from these casting runs, with the corresponding trial conditions.
Table 2: Results of the trials carried out on the type A, B and C casting runs According Casting Diameter of Reduc- Temperature Pore Other to the run type the rolling tion of the strip welding defects invention mill rolls ratio leaving the (mm) rolling mill
(OC)
no A 300 50 1100 no none no A 400 10 1100 no none no A 400 15 750 no none yes A,A',B,C 400 15 800 yes none yes A,A',B,C 400 15 1100 yes none no A 400 15 1150 yes excessive roughness no A 400 50 750 no none yes AA',B,C 400 50 800 yes none yes A,A',B,C 400 50 1100 yes none no A 400 50 1150 yes excessive roughness no A 400 60 1100 yes crazes no A 900 10 1100 no none no A 900 15 750 no none yes A,A',B,C 900 15 800 yes none yes A,A',B,C 900 15 1100 yes none no A 900 15 1150 yes excessive roughness no A 900 50 750 no none yes A,A',B,C 900 50 800 yes none yes A,A',B,C 900 50 1100 yes none no A 900 50 1150 yes excessive Sroughness no A 900 60 1100 yes crazes no A 1000 50 750 no none It is pore welding apparent is obtai from these trials that effective ned without the arppearance of surface surface cracks and without excessive roughness on the of the strip when the following three conditions are combined: a diameter of the rolling-mill work rolls of between 400 and 900 mm; a thickness reduction ratio of the strip during rolling of between 15 and 9 a temperature of the strip on leaving the rolling mill of at least 8000C and at most 11000C.
On the other hand, no influence was noted, under the trial conditions, of the strip thickness/casting speed combination: the results of the type A' casting runs are identical to those of the type A casting runs for casting parameters which are, moreover, identical.
As mentioned, these trials were carried out with a hot-rolling mill placed in line with the casting plant and before the strip coiling plant. Within the context of the invention, this characteristic is not absolutely essential and the hot rolling may be carried out on a plant separate from the casting and coiling plant, and therefore after the as-cast strip has been uncoiled and reheated. However, in-line rolling is recommended for various reasons. First of all, this solution has economic advantages associated with the continuous nature of the operations. In the first 20 instance, the strip manufacturing process is shortened.
In addition, a saving may be made by not having a coiler and also a relatively high-power reheat plant since the cast strip may be hot enough to obtain the suitable rolling temperatures, possibly with the aid of 25 a cover stopping the radiation from the strip between its exit from the casting rolls and its entry into the goof rolling mill. However, if it proves to be necessary to reheat the strip, this may be carried out using a lowpower induction furnace, the power being sufficient to raise the temperature of the running strip a few hundred degrees. Moreover, in-line rolling, dispensing with the need to coil the as-cast strip, eliminates by the same stroke the risk of damage to the strip during this coiling which would take place on a relatively thick strip having a non-recrystallized structure.
Finally, by not having to reheat the strip from room temperature up to the hot rolling temperature, surface reoxidation of the strip which normally occurs during this operation is eliminated. Such reoxidation would 10 form scale which would run the risk of being encrusted both into the strip and into the rolling-mill rolls, and thus of causing a degradation of the surface appearance of the product after pickling.
The invention applies not only to twin-roll casting plants but to any type of plant for casting thin stainless steel strip between two cooled moving surfaces, such as running strip.
Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
0* *o 0 o O* OO
Claims (4)
- 2. Process according to Claim 1, characterized in that the hot rolling is carried out on a plant placed in line with the casting plant.
- 3. Process according to Claim 1 or 2, 0 20 characterized in that the cooled walls of the casting plant consist of the surfaces of two rotating rolls having horizontal axes. e 9. 9* 9° 9 WOO 12 ,e 0* C. CS** C CC CC* C C@ S C 5* CS SW *c S.C. WI S CC a *CCC
- 4. Process for manufacturing stainless steel strip substantially as hereinbefore described with reference to the Examples. Stainless steel strip when manufactured by a process according to any one of claims 1 to 4.
- 6. The steps, features, compositions and compounds disclosed herein or referred to or indicated in the specification and/or claims of this application, individually or collectively, and any and all combinations of any two or more of said steps or features. DATED this SEVENTEENTH day of SEPTEMBER 1999 UGINE SA by DAVIES COLLISON CAVE Patent Attorneys for the applicant(s)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003266431A AU2003266431A1 (en) | 1998-09-21 | 2003-12-02 | Process for manufacturing a thin stainless steel strip |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR9811777A FR2783443B1 (en) | 1998-09-21 | 1998-09-21 | PROCESS FOR THE MANUFACTURE OF A STAINLESS STEEL THIN STRIP |
FR9811777 | 1998-09-21 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU2003266431A Division AU2003266431A1 (en) | 1998-09-21 | 2003-12-02 | Process for manufacturing a thin stainless steel strip |
Publications (1)
Publication Number | Publication Date |
---|---|
AU4877899A true AU4877899A (en) | 2000-03-23 |
Family
ID=9530674
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
AU48778/99A Abandoned AU4877899A (en) | 1998-09-21 | 1999-09-17 | Process for manufacturing a thin stainless steel strip |
Country Status (18)
Country | Link |
---|---|
EP (1) | EP0988901B1 (en) |
JP (1) | JP2000094006A (en) |
KR (1) | KR100573750B1 (en) |
CN (1) | CN100358645C (en) |
AT (1) | ATE253992T1 (en) |
AU (1) | AU4877899A (en) |
BR (1) | BR9904278A (en) |
CA (1) | CA2281991A1 (en) |
DE (1) | DE69912710T2 (en) |
FR (1) | FR2783443B1 (en) |
ID (1) | ID25947A (en) |
PL (1) | PL335499A1 (en) |
RU (1) | RU2203749C2 (en) |
SK (1) | SK123999A3 (en) |
TR (1) | TR199902306A2 (en) |
TW (1) | TW483781B (en) |
UA (1) | UA63941C2 (en) |
ZA (1) | ZA995983B (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
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DE10046181C2 (en) * | 2000-09-19 | 2002-08-01 | Krupp Thyssen Nirosta Gmbh | Process for producing a steel strip or sheet consisting predominantly of Mn austenite |
ITRM20070150A1 (en) * | 2007-03-21 | 2008-09-22 | Danieli Off Mecc | PROCESS AND PLANT FOR THE PRODUCTION OF METAL TAPES |
CN110404967A (en) * | 2019-07-16 | 2019-11-05 | 山西太钢不锈钢精密带钢有限公司 | The manufacturing method of the ultra-thin superhard stainless steel belt of ultra-wide and its steel band of manufacture |
CN114247760B (en) * | 2020-09-23 | 2024-02-13 | 宝山钢铁股份有限公司 | Comprehensive diagnosis method for cold rolling broken belt of brittle material |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
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JPH02224853A (en) | 1989-02-27 | 1990-09-06 | Kawasaki Steel Corp | Cooling roll for producing twin roll type rapidly cooling strip |
JP2798694B2 (en) | 1989-03-17 | 1998-09-17 | 新日本製鐵株式会社 | Manufacturing method of thin cast slab |
JPH03124352A (en) * | 1989-10-09 | 1991-05-27 | Kobe Steel Ltd | Production of continuously cast slab having excellent internal quality |
JP2690191B2 (en) * | 1990-11-30 | 1997-12-10 | 新日本製鐵株式会社 | Method for producing high δ-Fe-based austenitic stainless steel strip |
JP2995520B2 (en) * | 1992-10-20 | 1999-12-27 | 新日本製鐵株式会社 | How to improve the quality of continuous cast slabs |
JPH07251244A (en) * | 1994-03-16 | 1995-10-03 | Nippon Steel Corp | Method for preventing porosity of cast slab in twin roll type continuous casting method |
WO1996001710A1 (en) * | 1994-07-08 | 1996-01-25 | Ipsco Inc. | Method of casting and rolling steel using twin-roll caster |
JPH08215797A (en) * | 1995-02-16 | 1996-08-27 | Nippon Steel Corp | Production of austenitic stainless steel thin cast slab excellent in surface characteristic and formability |
JP2982646B2 (en) * | 1995-03-16 | 1999-11-29 | 住友金属工業株式会社 | Continuous production of thin steel sheets |
-
1998
- 1998-09-21 FR FR9811777A patent/FR2783443B1/en not_active Expired - Fee Related
-
1999
- 1999-09-09 CA CA002281991A patent/CA2281991A1/en not_active Abandoned
- 1999-09-10 EP EP99402235A patent/EP0988901B1/en not_active Revoked
- 1999-09-10 DE DE69912710T patent/DE69912710T2/en not_active Revoked
- 1999-09-10 AT AT99402235T patent/ATE253992T1/en not_active IP Right Cessation
- 1999-09-10 SK SK1239-99A patent/SK123999A3/en unknown
- 1999-09-17 AU AU48778/99A patent/AU4877899A/en not_active Abandoned
- 1999-09-18 ZA ZA9905983A patent/ZA995983B/en unknown
- 1999-09-20 PL PL99335499A patent/PL335499A1/en unknown
- 1999-09-20 ID IDP990877D patent/ID25947A/en unknown
- 1999-09-20 CN CNB991220633A patent/CN100358645C/en not_active Expired - Fee Related
- 1999-09-20 RU RU99120100/02A patent/RU2203749C2/en not_active IP Right Cessation
- 1999-09-20 KR KR1019990040351A patent/KR100573750B1/en not_active IP Right Cessation
- 1999-09-20 TR TR1999/02306A patent/TR199902306A2/en unknown
- 1999-09-20 UA UA99095183A patent/UA63941C2/en unknown
- 1999-09-21 BR BR9904278-9A patent/BR9904278A/en active Search and Examination
- 1999-09-21 JP JP11266489A patent/JP2000094006A/en active Pending
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Also Published As
Publication number | Publication date |
---|---|
TR199902306A3 (en) | 2000-04-21 |
KR100573750B1 (en) | 2006-04-24 |
KR20000023300A (en) | 2000-04-25 |
DE69912710T2 (en) | 2004-09-23 |
TW483781B (en) | 2002-04-21 |
RU2203749C2 (en) | 2003-05-10 |
EP0988901B1 (en) | 2003-11-12 |
ID25947A (en) | 2000-11-16 |
FR2783443A1 (en) | 2000-03-24 |
CN1249216A (en) | 2000-04-05 |
ZA995983B (en) | 2001-03-19 |
TR199902306A2 (en) | 2000-04-21 |
ATE253992T1 (en) | 2003-11-15 |
JP2000094006A (en) | 2000-04-04 |
PL335499A1 (en) | 2000-03-27 |
CA2281991A1 (en) | 2000-03-21 |
DE69912710D1 (en) | 2003-12-18 |
CN100358645C (en) | 2008-01-02 |
UA63941C2 (en) | 2004-02-16 |
BR9904278A (en) | 2000-09-26 |
EP0988901A1 (en) | 2000-03-29 |
SK123999A3 (en) | 2000-07-11 |
FR2783443B1 (en) | 2000-10-27 |
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