US20070199631A1 - Method for producing a hot strip from a steel which has a high manganese content - Google Patents
Method for producing a hot strip from a steel which has a high manganese content Download PDFInfo
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- US20070199631A1 US20070199631A1 US11/796,245 US79624507A US2007199631A1 US 20070199631 A1 US20070199631 A1 US 20070199631A1 US 79624507 A US79624507 A US 79624507A US 2007199631 A1 US2007199631 A1 US 2007199631A1
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- strip
- hot
- roughed
- weight
- steel
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 25
- 239000010959 steel Substances 0.000 title claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 title claims description 4
- 239000011572 manganese Substances 0.000 title abstract description 9
- 229910052748 manganese Inorganic materials 0.000 title abstract description 8
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 title abstract description 7
- 238000005266 casting Methods 0.000 claims abstract description 30
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 claims abstract description 3
- 238000000034 method Methods 0.000 claims description 21
- 238000001816 cooling Methods 0.000 claims description 14
- 238000005096 rolling process Methods 0.000 claims description 10
- 238000005098 hot rolling Methods 0.000 claims description 6
- 239000000155 melt Substances 0.000 claims description 5
- 230000001681 protective effect Effects 0.000 claims description 5
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 239000012080 ambient air Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 238000003303 reheating Methods 0.000 claims description 2
- 239000002994 raw material Substances 0.000 description 16
- 238000007711 solidification Methods 0.000 description 11
- 230000008023 solidification Effects 0.000 description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 239000007789 gas Substances 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 239000002826 coolant Substances 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 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
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
- C21D8/0215—Rapid solidification; Thin strip casting
-
- 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
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot 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
- B21B1/463—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
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B9/00—Measures for carrying out rolling operations under special conditions, e.g. in vacuum or inert atmosphere to prevent oxidation of work; Special measures for removing fumes from rolling mills
Definitions
- the invention relates to a method for producing a hot strip from a steel which has a high manganese content of more than 12 to 30 weight %. Steels of this type are characterised by particularly high strength.
- steels which apart from other alloying elements comprise 7% to 27% Mn can be produced by thin-strip casting to form a strip which is close to the final dimensions, and can be processed into hot strip.
- the material obtained in this way is particularly suitable for application in the area of motor car body construction.
- This object is met by a method for producing a hot strip with TWIP and TRIP characteristics, from a steel which comprises more than 12 to 30 weight % of manganese, in which a melt is cast in a double-roller casting machine to form a roughed strip close to the final dimensions, said roughed strip comprising a thickness of up to 6 mm, which roughed strip, following casting, is further continuously processed to form hot strip by being rolled in a single hot roll pass to the final thickness of the hot strip.
- highly manganiferous steel is cast to form a raw material whose dimensions approximate the final dimensions of the hot strip.
- the material produced is so thin that essentially uniform solidification across its entire cross section is ensured.
- the microstructure of the raw material which was cast to be so close to final dimensions is essentially of finer grain and more uniform than is the case in steel strip with a comparatively high manganese content, which was produced in the conventional way.
- the hot strip produced from the raw material has TRIP (“Transformation Induced Plasticity”) and TWIP (“Twinning Induced Plasticity”) characteristics and consequently is of good deformability which in combination with its high strength make it eminently suitable for use in motor car body construction.
- the material produced should be as thin as possible.
- the solidification process can easily be controlled in a targeted way.
- a controlled process can take account of the fact that, in particular in the case of steels under discussion in this document, the solidification rate has a direct influence on the extent and distribution of micro segregation. This in turn has an influence on grain growth and on the state of the precipitation such as of MnS, AlN and Ti (C, N) which occurs during solidification.
- the microstructure parameters of the cast raw material it is thus possible to select the basic settings which have a decisive influence on the ability for further processing and on the usage characteristics of the end product.
- the steel is cast in a double-roller casting machine.
- This type of casting machine which is known per se, makes it possible to produce particularly thin raw material which closely approximates the final dimension of the hot strip, with the solidification behaviour, in particular the solidification rate and uniformity of solidification, of such raw material resulting in an optimum cast structure and, associated with it, in optimum deformability.
- further processing of the raw material to form hot strip comprises controlled cooling, which takes place immediately after casting. This makes it possible to cool in a targeted way the raw material issuing from the casting mould so as to obtain a microstructure which is optimised for further processing. As a rule, cooling will take place at a rate which is accelerated when compared to cooling by exposure to ambient air.
- the average initial rolling temperature at which the raw material enters the roll stand can range between 1100° C. and 750° C.
- the characteristics of the hot-rolled strip can furthermore be influenced in a targeted way in that, following hot rolling, the rolled hot strip is cooled in a controlled way.
- steels which are used according to the invention can comprise up to 3.5 weight %, in particular up to 3 weight %, silicon. Moreover, they can comprise up to 3.5 weight %, in particular up to 3 weight %, aluminium. In steel of the type processed according to the invention, iron and aluminium or iron and silicon form intermetallic phases which occur below the hot forming temperature and which are stable to room temperature.
- FIG. 1 A lateral diagrammatic view of the design of a device for producing hot strip
- FIG. 2 The temperature course during the processing time of the roughed strip and the hot strip in a device according to FIG. 1 ;
- FIG. 3 a An enlarged section of the edge region of the hot strip produced in the device according to FIG. 1 ;
- FIG. 3 b An enlarged section of the centre region of the hot strip produced in the device according to FIG. 1 .
- FIG. 1 diagrammatically shows the design of a device 1 for producing a hot strip W, said device comprising a casting device 2 , a first cooling section 3 , a roll stand 4 , a second cooling section 5 , and a coiling device 6 .
- a melt S contained in a tundish 7 is poured into the casting gap 10 formed between two casting rollers 8 , 9 , to form roughed strip V.
- the cast roughed strip V leaves the casting gap 10 in a continuous conveying process at a thickness which can be varied between less than 1 mm and 6 mm.
- the roughed strip V On its way to the roll stand 4 , the roughed strip V is cooled in a controlled way by means of a cooling medium applied to the surfaces of said roughed strip V in the first cooling section 3 which is arranged below the exit of the casting gap 10 and closely adjacent to it.
- the conveyor section along which the thin strip V passes between the exit of the casting gap 10 and the roll stand 4 is surrounded by a dog house 11 in which a protective gas atmosphere is maintained. In this way, contact between the surface of the strip and the oxygen of the ambient air is avoided.
- the thin strip V enters the roll stand 4 at an initial rolling temperature AT, and in said roll stand is rolled to final thickness in one pass.
- the hot strip W which leaves the roll stand 4 at a final rolling temperature ET passes through the second cooling section 5 .
- the hot strip W is again brought in a controlled way to the coiling temperature HT by means of a suitable cooling medium, before being coiled in the coiling device 6 , at said coiling temperature HT, to form a coil C.
- FIG. 2 shows the initial rolling temperature AT, the final rolling temperature ET and the coiling temperature HT during the processing time after casting in the strip widths which, depending on the composition and the desired characteristics of the hot strip to be produced, can be set in a device designed according to FIG. 1 .
- suitable temperature control management along a specified limiting curve with subsequent isothermal holding, rolling and quenching, the fine grained microstructure of the hot strip can be frozen after the hot strip exits from the roll stand, so that the good usage characteristics of the hot strip remain after hot rolling. This effect can be achieved in particular when the temperature course of the roughed strip and hot strip approximates the lower limiting curve shown in the diagram ( FIG. 2 ).
- the melt S which was poured in the embodiment shown comprised an Mn content of 20 weight %, a C content of 0.003 weight %, a sulphur content of 0.007 weight %, an Si content of 3.0 weight %, an Al content of 3.0 weight %, with the remainder being iron.
- FIG. 3 a shows an enlarged section of the edge region
- FIG. 3 b shows an equally enlarged section of the centre region of a steel made from a hot strip produced in a device shown in FIG. 1 .
- the strip comprises a dendritic microstructure comprising austenite and a second phase which is probably a carboniferous phase.
- the microstructure becomes significantly finer towards the core of the strip.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Physics & Mathematics (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Metal Rolling (AREA)
- Continuous Casting (AREA)
- Heat Treatment Of Sheet Steel (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
A steel strip can be produced which in spite of its high manganese content has good deformation behaviour in that, according to the invention, from a steel which comprises more than 12 to 30 weight % of manganese, a roughed strip (V) is cast close to the final dimensions in a double-roller casting machine (2), said roughed strip comprising a thickness of up to 6 mm. Following casting, this roughed strip is further processed to form a continuous hot strip by preferably being rolled in a single hot roll pass.
Description
- This application is a continuation application of U.S. Ser. No. 10/433,729, filed on Oct. 7, 2003. U.S. Ser. No. 10/433,729 is a national stage of PCT/EP01/14306, filed on Dec. 6, 2001. PCT/EP01/14306 originates from German application DE 100 69 948.1, filed on Dec. 6, 2000. The disclosures of each application listed above are incorporated by reference in their entireties.
- The invention relates to a method for producing a hot strip from a steel which has a high manganese content of more than 12 to 30 weight %. Steels of this type are characterised by particularly high strength.
- There is a problem when producing and processing steels with such high manganese contents in that their solidification behaviour differs from that of steels which are commonly used for deep-drawing applications, for example IF or Low-carbon steels. It has thus been shown that steels of the type in question with a high manganese content, which steels have been cast in conventional continuous slab casting, have poor deformation behaviour.
- According to a method known from DE 199 00 199 A1, steels which apart from other alloying elements comprise 7% to 27% Mn can be produced by thin-strip casting to form a strip which is close to the final dimensions, and can be processed into hot strip. The material obtained in this way is particularly suitable for application in the area of motor car body construction.
- It is the object of the invention to provide a method which makes it possible to produce steel strip of good deformation behaviour, in spite of a high manganese content.
- This object is met by a method for producing a hot strip with TWIP and TRIP characteristics, from a steel which comprises more than 12 to 30 weight % of manganese, in which a melt is cast in a double-roller casting machine to form a roughed strip close to the final dimensions, said roughed strip comprising a thickness of up to 6 mm, which roughed strip, following casting, is further continuously processed to form hot strip by being rolled in a single hot roll pass to the final thickness of the hot strip.
- According to the invention, highly manganiferous steel is cast to form a raw material whose dimensions approximate the final dimensions of the hot strip. In this way during the casting process already, the material produced is so thin that essentially uniform solidification across its entire cross section is ensured. Surprisingly, it has been shown that the microstructure of the raw material which was cast to be so close to final dimensions is essentially of finer grain and more uniform than is the case in steel strip with a comparatively high manganese content, which was produced in the conventional way. The hot strip produced from the raw material has TRIP (“Transformation Induced Plasticity”) and TWIP (“Twinning Induced Plasticity”) characteristics and consequently is of good deformability which in combination with its high strength make it eminently suitable for use in motor car body construction.
- According to the invention, the material produced should be as thin as possible. The thinner the cast raw material, the finer the solidification microstructure, and the less scope there is for flaws due to solidification impeding the further processing to form hot strip. At the same time, in a thin cast raw material, the solidification process can easily be controlled in a targeted way. Thus, a controlled process can take account of the fact that, in particular in the case of steels under discussion in this document, the solidification rate has a direct influence on the extent and distribution of micro segregation. This in turn has an influence on grain growth and on the state of the precipitation such as of MnS, AlN and Ti (C, N) which occurs during solidification. As a result of targeted control of the microstructure parameters of the cast raw material, it is thus possible to select the basic settings which have a decisive influence on the ability for further processing and on the usage characteristics of the end product.
- According to the invention, the steel is cast in a double-roller casting machine. This type of casting machine, which is known per se, makes it possible to produce particularly thin raw material which closely approximates the final dimension of the hot strip, with the solidification behaviour, in particular the solidification rate and uniformity of solidification, of such raw material resulting in an optimum cast structure and, associated with it, in optimum deformability.
- Surprisingly it has been shown that particularly good work-results can be achieved in that from the roughed strip, a hot strip is rolled to its final thickness in only a single pass. The immediate continuous sequence of the casting process and hot rolling in one pass makes it possible to take the heat of the casting process along into the rolling process. Consequently, the step of reheating before hot rolling, a step which is always required in conventional slab casting, can be avoided. “Taking along” the casting heat also prevents excessive crystal growth, thus additionally supporting the formation of a fine microstructure in the raw material.
- Due to the particular influence of the solidification process on the characteristics of the final product it is advantageous if further processing of the raw material to form hot strip comprises controlled cooling, which takes place immediately after casting. This makes it possible to cool in a targeted way the raw material issuing from the casting mould so as to obtain a microstructure which is optimised for further processing. As a rule, cooling will take place at a rate which is accelerated when compared to cooling by exposure to ambient air.
- Experiments have shown that, depending on the composition and the desired characteristics of the end product, the average initial rolling temperature at which the raw material enters the roll stand can range between 1100° C. and 750° C.
- If the raw material is hot rolled, the characteristics of the hot-rolled strip can furthermore be influenced in a targeted way in that, following hot rolling, the rolled hot strip is cooled in a controlled way.
- In principle it is imaginable to further process the hot strip obtained according to the invention “inline”, for example to form a cold strip. However, with a view to possibly following process steps, or to characteristics of the hot strip to be set, it will in many cases be expedient for the strip to be coiled as part of further processing.
- As a result of further processing of the raw material to form hot strip, at least in sections taking place in a protective gas atmosphere, oxidation of the strip surface, and associated with it excessive scale formation, can be avoided. In this context it is particularly favourable if the raw material is kept in the protective gas atmosphere at least until said raw material enters the roll stand.
- Apart from further alloying elements, steels which are used according to the invention can comprise up to 3.5 weight %, in particular up to 3 weight %, silicon. Moreover, they can comprise up to 3.5 weight %, in particular up to 3 weight %, aluminium. In steel of the type processed according to the invention, iron and aluminium or iron and silicon form intermetallic phases which occur below the hot forming temperature and which are stable to room temperature.
- Below, the invention is explained in more detail by means of one embodiment. The following are shown:
-
FIG. 1 A lateral diagrammatic view of the design of a device for producing hot strip; -
FIG. 2 The temperature course during the processing time of the roughed strip and the hot strip in a device according toFIG. 1 ; -
FIG. 3 a An enlarged section of the edge region of the hot strip produced in the device according toFIG. 1 ; and -
FIG. 3 b An enlarged section of the centre region of the hot strip produced in the device according toFIG. 1 . -
FIG. 1 diagrammatically shows the design of adevice 1 for producing a hot strip W, said device comprising acasting device 2, afirst cooling section 3, aroll stand 4, asecond cooling section 5, and acoiling device 6. - In a double-
roller casting machine 2 designed according to the known principle, a melt S contained in a tundish 7, with the melt composition being explained in detail below, is poured into thecasting gap 10 formed between twocasting rollers casting gap 10 in a continuous conveying process at a thickness which can be varied between less than 1 mm and 6 mm. - On its way to the
roll stand 4, the roughed strip V is cooled in a controlled way by means of a cooling medium applied to the surfaces of said roughed strip V in thefirst cooling section 3 which is arranged below the exit of thecasting gap 10 and closely adjacent to it. - The conveyor section along which the thin strip V passes between the exit of the
casting gap 10 and theroll stand 4 is surrounded by adog house 11 in which a protective gas atmosphere is maintained. In this way, contact between the surface of the strip and the oxygen of the ambient air is avoided. - The thin strip V enters the
roll stand 4 at an initial rolling temperature AT, and in said roll stand is rolled to final thickness in one pass. - Immediately thereafter, the hot strip W which leaves the roll stand 4 at a final rolling temperature ET passes through the
second cooling section 5. In thecooling section 5, the hot strip W is again brought in a controlled way to the coiling temperature HT by means of a suitable cooling medium, before being coiled in thecoiling device 6, at said coiling temperature HT, to form a coil C. -
FIG. 2 shows the initial rolling temperature AT, the final rolling temperature ET and the coiling temperature HT during the processing time after casting in the strip widths which, depending on the composition and the desired characteristics of the hot strip to be produced, can be set in a device designed according toFIG. 1 . By means of suitable temperature control management along a specified limiting curve, with subsequent isothermal holding, rolling and quenching, the fine grained microstructure of the hot strip can be frozen after the hot strip exits from the roll stand, so that the good usage characteristics of the hot strip remain after hot rolling. This effect can be achieved in particular when the temperature course of the roughed strip and hot strip approximates the lower limiting curve shown in the diagram (FIG. 2 ). - Apart from the usual unavoidable impurities, the melt S which was poured in the embodiment shown comprised an Mn content of 20 weight %, a C content of 0.003 weight %, a sulphur content of 0.007 weight %, an Si content of 3.0 weight %, an Al content of 3.0 weight %, with the remainder being iron.
-
FIG. 3 a shows an enlarged section of the edge region, whileFIG. 3 b shows an equally enlarged section of the centre region of a steel made from a hot strip produced in a device shown inFIG. 1 . It is evident that the strip comprises a dendritic microstructure comprising austenite and a second phase which is probably a carboniferous phase. The microstructure becomes significantly finer towards the core of the strip. -
- 1 Device
- 2 Double-roller casting machine
- 3 First cooling section
- 4 Roll stand
- 5 Second cooling section
- 6 Coiling device
- 7 Tundish
- 8,9 Casting rollers
- 10 Casting gap
- 11 Dog house
- AT Initial rolling temperature
- C Coil
- ET Final rolling temperature
- S Melt
- V Thin strip
- W Hot strip
Claims (14)
1. A method for producing a steel hot strip with TWIP and TRIP characteristics from a steel which comprises more than 12 weight % and up to 30 weight % of manganese, comprising
casting a melt in a double-roller casting machine so as to form a roughed strip at close to the final dimensions of said hot strip, said roughed strip having a thickness of up to 6 mm,
immediately after said casting step and without reheating said roughed strip, continuously processing said roughed strip by being hot rolled in a roll stand in a single hot roll pass to the final thickness of the hot strip, said hot strip having a fine-grained dendritic microstructure after the single hot roll pass.
2. The method of claim 1 wherein the thickness of the roughed strip is up to 4 mm.
3. The method of claim 1 wherein the thickness of the roughed strip is up to 2.5 mm.
4. The method of claim 1 further comprising cooling said roughed strip under controlled conditions immediately after casting.
5. The method of claim 4 wherein said cooling is conducted at a rate which is greater than the rate of cooling by exposure to ambient air.
6. The method of claim 1 wherein the average initial rolling temperature at which the roughed strip enters the roll stand for hot rolling is in the range between 750° C. and 1,100° C.
7. The method of claim 1 further comprising cooling the hot strip under controlled conditions after hot rolling to freeze in the fine-grained dendritic microstructure.
8. The method of claim 1 further comprising coiling the hot strip.
9. The method of claim 1 wherein processing of the roughed strip to form said hot strip takes place, at least in sections, in a protective gas atmosphere.
10. The method of claim 9 wherein the roughed strip is kept under said protective gas atmosphere at least until it enters said roll stand.
11. The method of claim 1 wherein the steel comprises up to 3.5 weight % of silicon.
12. The method of claim 1 wherein said steel comprises up to 3 weight % of silicon.
13. The method of claim 1 wherein said steel comprises up to 3.5 weight % aluminum.
14. The method of claim 1 wherein the steel comprises up to 3 weight % of aluminum.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/796,245 US20070199631A1 (en) | 2000-12-06 | 2007-04-27 | Method for producing a hot strip from a steel which has a high manganese content |
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10060948A DE10060948C2 (en) | 2000-12-06 | 2000-12-06 | Process for producing a hot strip from a steel with a high manganese content |
DE10069948.1 | 2000-12-06 | ||
US10/433,729 US20040074628A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
PCT/EP2001/014306 WO2002046480A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
US11/796,245 US20070199631A1 (en) | 2000-12-06 | 2007-04-27 | Method for producing a hot strip from a steel which has a high manganese content |
Related Parent Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2001/014306 Continuation WO2002046480A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
US10/433,729 Continuation US20040074628A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
Publications (1)
Publication Number | Publication Date |
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US20070199631A1 true US20070199631A1 (en) | 2007-08-30 |
Family
ID=7666209
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/433,729 Abandoned US20040074628A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
US11/796,245 Abandoned US20070199631A1 (en) | 2000-12-06 | 2007-04-27 | Method for producing a hot strip from a steel which has a high manganese content |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/433,729 Abandoned US20040074628A1 (en) | 2000-12-06 | 2001-12-06 | Method for producing a hot rolled strip made of a steel comprising a high content of manganese |
Country Status (11)
Country | Link |
---|---|
US (2) | US20040074628A1 (en) |
EP (1) | EP1341937B1 (en) |
JP (1) | JP3836793B2 (en) |
CN (1) | CN1236076C (en) |
AT (1) | ATE267269T1 (en) |
AU (1) | AU2002231664A1 (en) |
CZ (1) | CZ304928B6 (en) |
DE (2) | DE10060948C2 (en) |
ES (1) | ES2221659T3 (en) |
PL (1) | PL196538B1 (en) |
WO (1) | WO2002046480A1 (en) |
Cited By (4)
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US8852356B2 (en) | 2009-03-11 | 2014-10-07 | Salzgitter Glachstahl GmbH | Method for producing a hot rolled strip and hot rolled strip produced from ferritic steel |
CN106583454A (en) * | 2016-12-30 | 2017-04-26 | 宁波大学 | Continuous casting-cross wedge rolling moulding method for stud bar-free double-metal layer composite solid shafts |
CN106734203A (en) * | 2016-12-30 | 2017-05-31 | 宁波大学 | A kind of continuous casting-cross wedge rolling forming method without material head double-metal layer composite hollow axle |
US10450624B2 (en) | 2013-07-10 | 2019-10-22 | Thyssenkrupp Steel Europe Ag | Method for producing a flat product from an iron-based shape memory alloy |
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JP2004050220A (en) * | 2002-07-18 | 2004-02-19 | Ishikawajima Harima Heavy Ind Co Ltd | Facility for producing strip |
DE10259230B4 (en) * | 2002-12-17 | 2005-04-14 | Thyssenkrupp Stahl Ag | Method for producing a steel product |
DE102004054444B3 (en) * | 2004-08-10 | 2006-01-19 | Daimlerchrysler Ag | Method for making steel articles with high rigidity and plasticity comprises mechanical shaping of steel in which twinning induce plasticity or shearband induced plasticity is produced, to give increase in rigidity of at least 30 percent |
US20090010793A1 (en) * | 2004-11-03 | 2009-01-08 | Thyssenkrupp Steel Ag | Method For Producing High Strength Steel Strips or Sheets With Twip Properties, Method For Producing a Component and High-Strength Steel Strip or Sheet |
FR2878257B1 (en) * | 2004-11-24 | 2007-01-12 | Usinor Sa | PROCESS FOR MANUFACTURING AUSTENITIC STEEL SHEET, FER-CARBON-MANGANIZED WITH VERY HIGH RESISTANCE AND ELONGATION CHARACTERISTICS, AND EXCELLENT HOMOGENEITY |
DE102005052774A1 (en) * | 2004-12-21 | 2006-06-29 | Salzgitter Flachstahl Gmbh | Method of producing hot strips of lightweight steel |
DE102005010243A1 (en) * | 2005-03-05 | 2006-09-07 | Sms Demag Ag | Method and plant for producing a lightweight steel with a high manganese content |
JP4555183B2 (en) * | 2005-07-15 | 2010-09-29 | 株式会社神戸製鋼所 | Manufacturing method of forming aluminum alloy sheet and continuous casting apparatus for forming aluminum alloy |
DE102007059007A1 (en) | 2007-12-06 | 2009-06-18 | Salzgitter Flachstahl Gmbh | Producing hot-rolled strip from triplex structural steel for automobile industry, by casting melt in horizontal strip casting plant, free of bends and with killed-flow to form pre-strip and then rolling with deformation grade to give strip |
DE102007059006A1 (en) | 2007-12-06 | 2009-06-10 | Salzgitter Flachstahl Gmbh | Production of hot strip from transition-free ferritic steel comprises casting melt in horizontal strip casting unit to produce semi-finished strip of specified thickness which is then rolled with specified degree of deformation |
DE102008005158A1 (en) | 2008-01-18 | 2009-07-23 | Robert Bosch Gmbh | Automotive fuel injection component for diesel or petrol engine is machined from austenitic steel having transformation induced plasticity |
DE102009030324A1 (en) * | 2009-06-24 | 2011-01-05 | Voestalpine Stahl Gmbh | Manganese steel and process for producing the same |
US10001228B2 (en) * | 2011-06-17 | 2018-06-19 | National Oilwell Varco Denmark I/S | Unbonded flexible pipe |
CN108655354B (en) * | 2018-06-07 | 2019-12-27 | 东北大学 | Short-process preparation method of high-strength-ductility medium manganese steel thin strip |
CN110899644A (en) * | 2018-09-14 | 2020-03-24 | 宝山钢铁股份有限公司 | Production method of ultrathin hot rolled strip steel |
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US5647922A (en) * | 1994-03-25 | 1997-07-15 | Pohang Iron & Steel Co., Ltd. | Process for manufacturing high manganese hot rolled steel sheet without any crack |
US6358338B1 (en) * | 1999-07-07 | 2002-03-19 | Usinor | Process for manufacturing strip made of an iron-carbon-manganese alloy, and strip thus produced |
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- 2000-12-06 DE DE10060948A patent/DE10060948C2/en not_active Expired - Fee Related
-
2001
- 2001-12-06 ES ES01991793T patent/ES2221659T3/en not_active Expired - Lifetime
- 2001-12-06 DE DE50102363T patent/DE50102363D1/en not_active Expired - Lifetime
- 2001-12-06 WO PCT/EP2001/014306 patent/WO2002046480A1/en active IP Right Grant
- 2001-12-06 US US10/433,729 patent/US20040074628A1/en not_active Abandoned
- 2001-12-06 AT AT01991793T patent/ATE267269T1/en active
- 2001-12-06 AU AU2002231664A patent/AU2002231664A1/en not_active Abandoned
- 2001-12-06 CZ CZ2003-1558A patent/CZ304928B6/en not_active IP Right Cessation
- 2001-12-06 EP EP01991793A patent/EP1341937B1/en not_active Expired - Lifetime
- 2001-12-06 CN CN01816434.XA patent/CN1236076C/en not_active Expired - Fee Related
- 2001-12-06 JP JP2002548196A patent/JP3836793B2/en not_active Expired - Fee Related
- 2001-12-06 PL PL362508A patent/PL196538B1/en unknown
-
2007
- 2007-04-27 US US11/796,245 patent/US20070199631A1/en not_active Abandoned
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US4331474A (en) * | 1980-09-24 | 1982-05-25 | Armco Inc. | Ferritic stainless steel having toughness and weldability |
US5431753A (en) * | 1991-12-30 | 1995-07-11 | Pohang Iron & Steel Co. Ltd. | Manufacturing process for austenitic high manganese steel having superior formability, strengths and weldability |
US5647922A (en) * | 1994-03-25 | 1997-07-15 | Pohang Iron & Steel Co., Ltd. | Process for manufacturing high manganese hot rolled steel sheet without any crack |
US6387192B1 (en) * | 1997-07-01 | 2002-05-14 | Georg Frommeyer | Light constructional steel and the use thereof |
US6358338B1 (en) * | 1999-07-07 | 2002-03-19 | Usinor | Process for manufacturing strip made of an iron-carbon-manganese alloy, and strip thus produced |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8852356B2 (en) | 2009-03-11 | 2014-10-07 | Salzgitter Glachstahl GmbH | Method for producing a hot rolled strip and hot rolled strip produced from ferritic steel |
US10450624B2 (en) | 2013-07-10 | 2019-10-22 | Thyssenkrupp Steel Europe Ag | Method for producing a flat product from an iron-based shape memory alloy |
CN106583454A (en) * | 2016-12-30 | 2017-04-26 | 宁波大学 | Continuous casting-cross wedge rolling moulding method for stud bar-free double-metal layer composite solid shafts |
CN106734203A (en) * | 2016-12-30 | 2017-05-31 | 宁波大学 | A kind of continuous casting-cross wedge rolling forming method without material head double-metal layer composite hollow axle |
Also Published As
Publication number | Publication date |
---|---|
PL196538B1 (en) | 2008-01-31 |
DE10060948C2 (en) | 2003-07-31 |
DE10060948A1 (en) | 2002-06-27 |
ATE267269T1 (en) | 2004-06-15 |
CN1236076C (en) | 2006-01-11 |
WO2002046480A1 (en) | 2002-06-13 |
EP1341937A1 (en) | 2003-09-10 |
ES2221659T3 (en) | 2005-01-01 |
EP1341937B1 (en) | 2004-05-19 |
JP3836793B2 (en) | 2006-10-25 |
JP2004515362A (en) | 2004-05-27 |
CN1466633A (en) | 2004-01-07 |
US20040074628A1 (en) | 2004-04-22 |
PL362508A1 (en) | 2004-11-02 |
AU2002231664A1 (en) | 2002-06-18 |
CZ20031558A3 (en) | 2004-02-18 |
CZ304928B6 (en) | 2015-01-28 |
DE50102363D1 (en) | 2004-06-24 |
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