EP4192993A1 - Procédé de production d'une bande d'acier revêtue, et procédé de production d'un produit d'acier trempé à partir de celle-ci - Google Patents
Procédé de production d'une bande d'acier revêtue, et procédé de production d'un produit d'acier trempé à partir de celle-ciInfo
- Publication number
- EP4192993A1 EP4192993A1 EP21759035.5A EP21759035A EP4192993A1 EP 4192993 A1 EP4192993 A1 EP 4192993A1 EP 21759035 A EP21759035 A EP 21759035A EP 4192993 A1 EP4192993 A1 EP 4192993A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- less
- strip
- steel strip
- steel
- coating
- 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.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 154
- 239000010959 steel Substances 0.000 title claims abstract description 154
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- 229910000760 Hardened steel Inorganic materials 0.000 title claims abstract description 7
- 238000010438 heat treatment Methods 0.000 claims abstract description 59
- 238000000034 method Methods 0.000 claims abstract description 56
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 25
- 239000010703 silicon Substances 0.000 claims abstract description 25
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 24
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 24
- 239000000155 melt Substances 0.000 claims abstract description 20
- 238000003618 dip coating Methods 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims description 66
- 239000011248 coating agent Substances 0.000 claims description 61
- 239000000463 material Substances 0.000 claims description 43
- 238000005096 rolling process Methods 0.000 claims description 32
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 31
- 238000005275 alloying Methods 0.000 claims description 28
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 24
- 238000009792 diffusion process Methods 0.000 claims description 23
- 229910052742 iron Inorganic materials 0.000 claims description 14
- 239000011572 manganese Substances 0.000 claims description 14
- 239000011651 chromium Substances 0.000 claims description 11
- 230000006698 induction Effects 0.000 claims description 11
- 239000010936 titanium Substances 0.000 claims description 11
- 229910052748 manganese Inorganic materials 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 9
- 239000001257 hydrogen Substances 0.000 claims description 9
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 8
- 229910052796 boron Inorganic materials 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 8
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 7
- 238000000137 annealing Methods 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 229910052698 phosphorus Inorganic materials 0.000 claims description 7
- 229910052717 sulfur Inorganic materials 0.000 claims description 7
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- PALQHNLJJQMCIQ-UHFFFAOYSA-N boron;manganese Chemical compound [Mn]#B PALQHNLJJQMCIQ-UHFFFAOYSA-N 0.000 claims description 6
- 239000010949 copper Substances 0.000 claims description 6
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 229910000617 Mangalloy Inorganic materials 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 4
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 4
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 239000011574 phosphorus Substances 0.000 claims description 4
- 239000011593 sulfur Substances 0.000 claims description 4
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 claims description 3
- 229910052787 antimony Inorganic materials 0.000 claims description 3
- 238000010924 continuous production Methods 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 229910052712 strontium Inorganic materials 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- 150000002739 metals Chemical class 0.000 claims description 2
- 150000002431 hydrogen Chemical class 0.000 claims 1
- 238000003754 machining Methods 0.000 claims 1
- 230000003746 surface roughness Effects 0.000 claims 1
- 239000004411 aluminium Substances 0.000 abstract description 2
- 239000000758 substrate Substances 0.000 description 33
- 239000010410 layer Substances 0.000 description 24
- 230000008569 process Effects 0.000 description 21
- 230000009467 reduction Effects 0.000 description 12
- 238000001816 cooling Methods 0.000 description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 7
- 229910045601 alloy Inorganic materials 0.000 description 7
- 239000000956 alloy Substances 0.000 description 7
- 230000001939 inductive effect Effects 0.000 description 7
- 239000010955 niobium Substances 0.000 description 7
- 238000007654 immersion Methods 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 238000004140 cleaning Methods 0.000 description 5
- 238000005097 cold rolling Methods 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 4
- 238000005520 cutting process Methods 0.000 description 4
- 238000011143 downstream manufacturing Methods 0.000 description 4
- 230000001976 improved effect Effects 0.000 description 4
- 229910000734 martensite Inorganic materials 0.000 description 4
- 239000011733 molybdenum Substances 0.000 description 4
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 3
- 239000010960 cold rolled steel Substances 0.000 description 3
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 3
- 230000008092 positive effect Effects 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
- 239000002344 surface layer Substances 0.000 description 3
- 239000011701 zinc Substances 0.000 description 3
- 229910052725 zinc Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- KMWBBMXGHHLDKL-UHFFFAOYSA-N [AlH3].[Si] Chemical compound [AlH3].[Si] KMWBBMXGHHLDKL-UHFFFAOYSA-N 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 238000009499 grossing Methods 0.000 description 2
- 238000005098 hot rolling Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 238000000465 moulding Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000789 Aluminium-silicon alloy Inorganic materials 0.000 description 1
- 241001676573 Minium Species 0.000 description 1
- 229910000676 Si alloy Inorganic materials 0.000 description 1
- 229910000794 TRIP steel Inorganic materials 0.000 description 1
- 229910000937 TWIP steel Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000005496 eutectics Effects 0.000 description 1
- 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 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000289 melt material Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000004080 punching Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/003—Apparatus
- C23C2/0038—Apparatus characterised by the pre-treatment chambers located immediately upstream of the bath or occurring locally before the dipping process
- C23C2/004—Snouts
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/024—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by cleaning or etching
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/12—Aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Definitions
- the invention relates to a method for producing coated steel strip, in particular for producing hot-formed steel products, and products correspondingly produced according to the method.
- aluminium-silicon-coated high-strength and ultra-high-strength tempered steels in particular manganese-boron-containing tempered steels such as 22MnB5 or 34MnB5, are used in practice for safety-relevant body components of motor vehicles.
- WO 2009/090555 A1 discloses a method for producing a hot-stamped coated steel section, comprising the steps of: pre-coating a steel strip with aluminum or aluminum alloy by hot dipping, the thickness of the pre-coating being 20 to 33 microns on each side, cutting the pre-coated strip of steel into a steel section, heating the steel section in a furnace, transferring the heated steel section into a die, hot stamping the steel section in the die, and cooling the steel section.
- WO 2020 020644 A1 discloses a method for producing a hardened steel product, comprising the steps of: providing a steel substrate with a base material made of hardenable steel; Coating the steel substrate with an aluminum minium-containing precoat of at least 34 microns thickness; flexible rolling of the precoated steel substrate; Working out a circuit board from the flexibly rolled strip material; heating the circuit board such that the base material of the circuit board is austenitized; Hot forming of the heated blank wherein the heated blank is formed and rapidly cooled to produce a hardened coated steel product.
- WO 2006/097237 A1 discloses a method and a system for hot-dip coating hot-rolled steel strip.
- the steel strip goes through a pickling station, a rinsing station, a drying station, a heating furnace and then a molten bath.
- the finished thickness and the thickness tolerance of the hot-dip coated steel strip are achieved by a controlled reduction in thickness in a roll stand in the process line, in that the finished thickness is checked by a thickness gauge at the outlet of the roll stand and deviations from the target thickness are fed back as a control signal to the adjustment of the roll stand.
- TWIP steel (“Twinning Induced Plasticity”) is known from US 2019/0218639 A1.
- TWIP steels have high manganese and carbon contents, have a stable austenitic structure and are characterized by very good formability with strong strain hardening.
- the manufacturing process comprises the steps: heating a slab with a defined alloy composition to over 1000°C and hot rolling with a final rolling temperature of at least 850°C, coiling at less than or equal to 580°C, first cold rolling with a reduction ratio of between 30 and 70%, recrystallization annealing between 700 and 900°C, second cold rolling with a reduction ratio between 1 and 50%, stress relief annealing at between 460 and 625°C, and hot dip coating in an aluminium-based melt with a temperature between 550 and 700°C or in a zinc-based melt with a temperature between 410 and 550°C.
- DE 10 2004 059 566 B3 discloses a method for hot-dip coating a strip made of high-strength steel, in particular TRIP steel, with zinc and/or aluminum.
- the strip is heated to 650 to 750°C in a continuous furnace in a reducing atmosphere.
- the surface which mainly consists of pure iron, is treated with a short heat treatment at up to 650 to 750°C in an im converted into an iron oxide layer in a reaction chamber with an oxidizing atmosphere integrated in a continuous furnace.
- the strip is then annealed in a reducing atmosphere by further heating up to a maximum of 900°C and then cooled to the melting bath temperature, with the iron oxide layer being reduced to pure iron.
- the temperature of the hot-dip zinc bath is about 480°C.
- the present invention is based on the object of proposing a method for producing coated steel strip and a correspondingly produced steel strip which has improved processability for downstream production processes, in particular for flexible rolling or hot forming.
- a method for producing coated steel strip in which steel strip made of hardenable steel is brought to a strip target temperature of less than 625° C., and the steel strip, heated to strip target temperature, in a melt containing aluminum and silicon and a temperature less than 620°C, is hot dip coated.
- the diffusion processes between the melt and the steel strip are relatively short or slight as a result of the hot-dip coating at the specified, relatively low temperature, so that a relatively thin diffusion layer is formed.
- the rollability or formability can be improved by lower rolling forces or forming forces. There is less friction between the tool and the coated steel strip, which has a positive effect on wear and the service life of the tool.
- a steel strip is used as the starting material, in particular made from a martensitic hardening steel material, which can be hot strip or cold strip.
- Hot strip is a finished rolled steel product (steel strip) that is produced by rolling after prior heating.
- Cold strip means a cold-rolled steel strip (flat steel).
- Flat steel is called cold-rolled, the last reduction in thickness is carried out by rolling without previous heating.
- Hot-rolled steel strip is preferably used, since this saves one manufacturing step, namely cold rolling before coating, and thus the corresponding costs. Insofar as the term steel strip is used within the scope of this disclosure, hot strip and cold strip are to be included accordingly.
- the steel strip can, for example, be made of a steel material that can be hardened or tempered, in particular that contains manganese. In addition to manganese, this can contain other micro-alloying elements, such as boron.
- a martensitic hardenable boron-manganese steel can in particular have a ferritic-pearlitic initial structure at room temperature and has comparatively good adhesion properties for the coating to be applied.
- the steel material can contain, for example, the following proportions of alloying elements, each in percent by weight: carbon (C) with at least 0.15% and at most 0.5%, in particular at most 0.4%; manganese (Mn) with at least 0.5% and at most 5.0%, in particular at least 0.8% and at most 2.5%; Aluminum (Al) with a maximum of 0.1%; Silicon (Si) with at least 0.1% and at most 0.9%, in particular at most 0.5%; Chromium (Cr) with at least 0.01% and at most 1.0%; titanium (Ti) with at most 0.05%, in particular at least 0.02%; Boron (B) with at least 0.0005% and at most 0.080%, in particular at least 0.002% and at most 0.006%; Phosphorus (P) with a maximum of 0.1%, in particular a maximum of 0.01%; Sulfur (S) with not more than 0.05%, in particular not more than 0.01%; optionally further alloying elements with a proportion of up to 1.55% (1550 ppm); the
- the substrate can contain in particular at least one of: copper (Cu) with a maximum of 0.1%, nickel (Ni) with a maximum of 0.1%, niobium (Nb) with a maximum of 0.1%, molybdenum ( Mo) with a maximum of 1.0%, vanadium (V) with a maximum of 0.25%, without being restricted to this.
- the mass fraction of the optional alloying elements can also be lower, for example molybdenum can also be contained with at most 0.8%, 0.5% or 0.25%.
- the mass fraction of the optional alloying elements is a maximum of 1.55% in total, in particular a maximum of 1.0%, in particular a maximum of 0.8%.
- the optional Alloying elements can in particular be chosen from the group of metals.
- the alloying element niobium advantageously brings about a fine-grained structure of a component hot-formed from the alloy.
- a particularly fine-grained structure results, which in turn has a favorable effect on the strength of the component made from it.
- usable boron-manganese steel materials are 17MnB5, 20MnB5, 20MnB8, 22MnB5, 26MnB5 or 34MnB5.
- the hot strip is preferably cleaned before coating, which can be done chemically, mechanically or electrochemically in particular. During cleaning, the solid burn-off (scale) that has occurred on the surface as a result of the hot-rolling process is removed.
- a common chemical or electrochemical process is pickling, which can be done, for example, in a continuous system in which the steel strip is conveyed through an acid bath.
- a hot strip can first be cold-rolled to a constant thickness in an intermediate step. The cold strip produced in this way is then cleaned, as described above, and coated, it being possible for the coating to be applied when the steel strip is in the as-rolled state. Before coating, the steel strip can have an initial thickness of 1.5 to 4.0 mm, for example.
- the strip target temperature to which the steel strip is brought before it is immersed in the molten bath is, for example, above 580.degree. C., in particular above 600.degree.
- the steel strip can in particular be brought to a strip target temperature of less than 620°C or also less than 610°C.
- the strip target temperature also includes a state immediately before or during immersion in the molten bath, ie the immersion temperature can be between 580 and 620° C., for example.
- the strip target temperature can be achieved directly by heating to the desired temperature, or indirectly by heating to a higher temperature and then cooling to the strip target temperature.
- the steel strip is preferably heated in a continuous process, for example by means of an induction furnace or a radiant tube furnace.
- the heating can take place in just one heating stage, which is particularly energy-efficient, and/or under a constantly reducing atmosphere, ie with a low oxygen content.
- the Strip target temperature (T3) can refer, for example, to the temperature of the steel strip at the exit or when leaving the furnace and/or at the entrance or when entering the melt.
- the steel strip can be heated to the strip target temperature (T3) at a rate (v) along a run length (L), preferably in an atmosphere with a hydrogen content (H2) of at least 30% by volume, preferably at least 50% by volume. %, and/or with an oxygen content (O2) of less than 10 ppm.
- the heating is carried out in particular in such a way that the ratio of the product of the target strip temperature (T3 in °C), passage length (L in m) of the induction furnace and hydrogen content (H2 in vol%) in the induction furnace, and the product of the heating rate ( f in °C/s) and speed (v in m/s) of the steel strip is greater than 96 s 2 and/or less than 192 s 2 [96 s 2 ⁇ (T3 * L * H2)/(t' * v ) ⁇ 192 s 2 ].
- the steel strip can be heated at a heating rate of more than 30 K/s, in particular more than 50 K/s.
- the heating time to the strip target temperature (T3) can be done in less than 60 seconds.
- the inductive heating carried out with one or more of the parameters mentioned produces a surface that can be coated very well. Together with the low coating temperature of in particular 580 to 620° C., preferably 600 to 610° C., a particularly thin diffusion zone is produced, which then contributes to an improvement in downstream manufacturing processes.
- the process management based on inductive heating in combination with the subsequent melt exchange coating can also be referred to as a heat-to-coat process.
- Inductive heating has the advantage of a very short glow time, which can be less than 60 s. This shortens the time it takes to activate or clean the surface. Therefore, annealing is preferably carried out using atmospheres with a comparatively high reduction potential in order to be able to ensure adequate wettability of the melt.
- the process according to the Sendzimir process which is used in particular for cold-rolled steel strips. Since the as-rolled structure produced by cold rolling must be recrystallized, heating preferably takes place in a radiant tube furnace that is large enough to recrystallize the material at more than 700°C for several minutes. Through the atmosphere set accordingly in this oven (hydrogen content, dew point, etc.) and a relatively long annealing time can ensure sufficient cleaning of the surface to make it wettable for the coating process.
- the steel strip can be heated to the strip target temperature (T3) by means of a radiant tube furnace, for example, at a heating rate of 10 K/s to 30 K/s.
- the glow time can be more than 120 seconds.
- the manganese and silicon contents of the substrate to be coated have a major influence on the coatability of the material, since oxides of the alloying elements can form during annealing, which impede wetting of the aluminium-silicon melt on the surface.
- the necessary recrystallization requires a temperature of over 700°C, which means that cooling between the furnace and immersion in the molten bath is necessary in order to keep the temperature of the molten bath below the target 620°C.
- the melt preferably contains at least 85% by weight aluminum, 5 to 15% by weight silicon, up to 5% by weight iron and optionally one or more other alloying elements in minor proportions.
- An exemplary composition of the molten bath or the applied coating can contain up to 3 percent by weight iron, 12 to 13 percent by weight silicon, optionally one or more other alloying elements with a total of up to 1.5 percent by weight, and the remainder aluminum. It goes without saying that unavoidable impurities may also be present.
- the proportion of the other alloying elements for example at least one from the group of Mn, Cr, Ti, B, P, S, Sr, Sb, Cu, Ni, Nb, Mo, V, can together be up to 1.5 percent by weight, for example.
- the coating alloy can be modified in such a way that a layered structure of intermetallic phases is created, with either a silicon-rich phase embedded in an aluminum-rich phase in addition to the interdiffusion zone, or a three-layer layer structure consisting of the interdiffusion zone and two aluminum phases that differ in iron and silicon content.
- the pre-coating is preferably applied to the steel strip to a thickness of at least 26 microns (pm), more preferably at least 34 microns (pm). Alternatively or additionally, the pre-coating is preferably applied to the steel strip with a thickness of at most 50 micrometers (pm), in particular at most 46 micrometers (pm).
- the hot-dip coating diffusion processes take place between the melt material and the hot-rolled strip material, with a diffusion layer having a thickness of preferably less than seven micrometers being formed. With a thickness of the pre-coating of 26 to 50 microns, the coating weight per side of the steel strip is about 78 to 150 g/m 2 .
- a steel strip is used that has a relatively high roughness, for which hot strip is particularly well suited since it has a higher initial roughness than cold strip.
- the steel strip used has a roughness for which at least one of the following applies: the roughness Ra is at least 0.8 and/or at most 2.0 microns; the roughness Rz is at least 4 and/or at most 12 microns; the roughness Rmax is at least 5 and/or at most 15 micrometers.
- the thickness of the pre-coating to be applied can be increased by a relatively high roughness. This has a positive effect against a later reduction in layer thickness in a possibly downstream manufacturing process, such as flexible rolling.
- the roughness changes slightly as a result of the coating, so that the following roughness values can result for the coated steel strip, for example: Ra: 0.4 to 3.0; Rz: 5 to 15; Rmax: 8 to 25.
- the object is further achieved by a method for producing a hardened steel product, comprising: providing a precoated steel strip which is produced according to at least one of the above-mentioned embodiments; flexible rolling of the precoated steel strip, successive sections of the precoated steel strip being rolled out to different extents; Carving out a blank from the flexibly rolled steel strip; Heating the circuit board in such a way that the base material of the circuit board is at least partially austenitized, diffusion processes taking place between the base material and the pre-coating as a result of the heating; and hot working the heated blank, wherein the heated blank formed and cooled so rapidly that a hardened coated steel product is produced.
- the thickness of the diffusion layer of the precoated steel strip is relatively thin. In this way, the growth of the diffusion zone is also reduced during the subsequent hot forming. As already mentioned above, the thin diffusion zone results in improved processability for the downstream manufacturing processes. The friction between the coated steel strip and the respective tool is reduced. With flexible rolling, rollability improves due to lower rolling forces, which has a positive effect on wear and service life. The same applies analogously to hot forming, where reduced friction between the blank and the forming tool analogously leads to lower forming forces and reduced tool wear.
- strip material with a substantially uniform sheet thickness in particular a uniform nominal Dieken size
- strip material with a variable sheet thickness over the length i.e. having different nominal Dieken dimensions over the length.
- the sections of different thickness produced by flexible rolling extend transversely to the longitudinal direction or rolling direction of the strip material.
- the strip material can be wound up again into a coil and fed to another point for further processing, or it can be further processed directly, for example by cutting the strip material to length into individual sheet metal elements.
- the flexible rolling can be carried out with reduction ratios of at least 1% and/or at most 60% based on the initial thickness of the precoated steel strip, in particular with reduction ratios between 3% and 55%. Due to the flexible rolling, the thickness of the pre-coating is reduced accordingly with the steel substrate. Depending on the desired component geometry, there can be any other desired thickness ranges or transitional regions between the thinnest sections and the thickest sections of the strip material. It goes without saying that further steps such as heating, to the coil or unwind from the coil, straighten, clean or the like can be interposed.
- the object is further achieved by a hot-formed steel product with a base material and an aluminum-silicon coating, which is produced in particular according to one of the above-mentioned methods, the steel product having a thickness of 1.5 to 4 mm; wherein the base material contains the above proportions of alloying elements; wherein the coating contains aluminum and silicon and has a thickness of at least 20 micrometers (pm) and at most 50 micrometers (pm); and wherein the coating comprises a diffusion layer less than 14 microns (14 ⁇ m) thick in the interface to the base material, an intermetallic layer thereover, and a surface layer overlying the intermetallic layer.
- the intermetallic layer may have a silicon content of 10 to 18% by weight and the surface layer 5 to 10% by weight.
- FIG. 1 shows a schematic of a method according to the invention for producing coated steel strip, in particular for producing hot-formed parts, in a first embodiment
- FIG. 2 shows a section of the coated steel strip after pre-coating in an enlarged schematic representation
- FIG. 3 shows a schematic of a method according to the invention for producing a coated, cured molded part
- FIG. 4 shows a section of the coated and flexibly rolled steel substrate after hot forming in an enlarged schematic representation
- FIG. 5 shows a schematic of a method according to the invention for producing coated steel strip, in particular for producing hot-formed parts, in a second embodiment.
- FIG. 1 shows a method according to the invention for producing a coated steel substrate.
- the steel substrate is also referred to as steel strip or generally as strip material.
- the steel substrate is also referred to as a blank.
- the coating method S10 comprises the sub-steps of heating the steel strip 2 to a target strip temperature T3 of less than 625° C. and hot dip coating of the steel strip 2, which has been heated to the target strip temperature, in a melt 4 made of an aluminum-silicon alloy, which is heated to a temperature T4 of less than 620 °C is set.
- the steel substrate 2 should include a particularly martensitic flat steel product made of boron-manganese steel, which can contain, for example, the following proportions of alloying elements in weight percent: carbon (C) with at least 0.15% and at most 0 .5%, in particular at most 0.4%; manganese (Mn) with at least 0.5% and at most 5.0%, in particular at least 0.8% and at most 2.5%; Aluminum (Al) with a maximum of 0.1%; Silicon (Si) with at least 0.1% and at most 0.9%, in particular at most 0.5%; chromium (Cr) with at least 0.01% and at most 1.0%; titanium (Ti) with at most 0.05%, in particular at most 0.01%; Boron (B) with at least 0.0005% and at most 0.080%, in particular at least 0.002% and at most 0.006%; Phosphorus (P) with a maximum of 0.1%, in particular a maximum of 0.01%; Sulfur (S) with at most
- This alloy composition includes, for example, boron-manganese steel materials such as 17MnB5, 20MnB5, 20MnB8, 22MnB5, 26MnB5 and 34MnB5.
- the steel material can have a yield point of, for example, 150 to 1100 MPa and/or a tensile strength of at least 450 MPa and/or a particularly ferritic-pearlitic structure at room temperature.
- the optional further alloying elements can be selected from the group: copper (Cu) with a maximum of 0.1%; nickel (Ni) with a maximum of 0.1%; niobium (Nb) with at most 0.1%; molybdenum (Mo) with a maximum of 1.0%; vanadium (V) with a maximum of 0.25%; without being limited thereto, with the stated percentages in each case Percentage by mass of the steel substrate.
- copper copper
- Ni nickel
- Nb niobium
- Mo molybdenum
- V vanadium
- the total mass fraction of the optional alloying elements is at most 1.55%, in particular at most 1.0%, preferably at most 0.8%.
- Hot-rolled strip or cold-rolled strip can be used as the steel substrate 2, with hot-rolled steel strip being particularly suitable for an efficient manufacturing process, since an additional manufacturing step, namely cold rolling before coating, can be omitted.
- the steel strip used preferably has a roughness of at least one of the following values: Ra of at least 0.8 and/or at most 2.0 microns; a roughness Rz of at least 4 and/or at most 12 microns; a roughness Rmax of at least 5 and/or at most 15 microns. Due to a relatively high roughness, the melt can adhere particularly well during the subsequent hot-dip coating, so that pre-coatings 8 with greater thicknesses can also be applied well.
- the steel substrate 2 can, for example, be unwound from a coil 6 by means of a reel 5 .
- the steel substrate can then optionally be cleaned in a cleaning device 7 before coating.
- the cleaning can be done chemically, mechanically or electrochemically, for example.
- the coating process S10 is continuously performed, and in the present embodiment, heating is performed in an induction furnace 3, but not limited thereto.
- the steel substrate passes through different furnace areas.
- the steel substrate is heated to the strip target temperature T3 at a speed v along a passage length L, preferably in an atmosphere with a hydrogen content (H2) of at least 30% by volume, preferably at least 50% by volume.
- H2 hydrogen content
- the heating is carried out in particular in such a way that the ratio of the product of the strip target temperature T3, the length L of the induction furnace and the hydrogen content (H2) in the induction furnace 3, and the product of the heating rate t' and the speed v of the steel strip 2 is greater than 96 s 2 and /or is less than 192 s 2 , i.e. 96 s 2 ⁇ (T3 * L * H2)/(t' *v ) ⁇ 192 s 2 .
- the passage length L can be 10 to 30 m, for example, and the speed v can be between 0.6 to 2 m/s, for example.
- steel strip can be heated at a heating rate of more than 30 K/s, in particular over 50 K/s. This applies above all to the temperature range from room temperature to 600°C.
- the heating time to the strip target temperature T3 can take place in less than 60 seconds.
- the strip target temperature to which the steel strip 2 is heated before it is immersed in the molten bath 4 is, for example, above 580°C, in particular above 600°C and/or less than 620°C, in particular less than 610°C.
- the steel strip 2 runs through the molten bath 4 in which it is provided with a pre-coating 8 .
- the steel strip 2 can have at least approximately the strip target temperature when it is immersed, that is to say the immersion temperature can in particular be above 580° C. and/or below 620° C.
- the alloy composition of the melt 4 determines the composition of the pre-coating 8 applied to the steel substrate 2.
- the melt 4 or the pre-coating 8 contains aluminum (Al) with at least 85 percent by weight and silicon (Si) with up to 15 percent by weight. It goes without saying that other alloying elements can also be included, for example iron and/or other alloying elements with a total of up to 5 percent by weight.
- the steel substrate 2 runs through the molten bath of liquid coating material in the coating plant 10, which adheres to the surface of the substrate 2, so that a pre-coated steel substrate 2' is produced.
- the melt of the coating material can contain, for example, 5 to 15 percent by weight silicon, 2 to 4 percent by weight iron, optionally one or more other alloying elements, such as at least one from the group consisting of Mn, Cr, Ti, B, P, S, Sr, Sb, Cu , Ni, Nb, Mo, V, together containing up to 1.5 percent by weight, and the remainder aluminum and unavoidable impurities.
- the reduction of the surface is subject to a thermal dependence: Due to a lower temperature in the reducing part of the furnace 3 at approx. 300 to 625 °C and a relatively short furnace length and the associated short residence time at these temperatures, there is relatively little time left for the surface of oxides to reduce. It is therefore favorable to set the furnace atmosphere appropriately and to anneal in the inlet area of furnace 3 at very high heating rates of more than 20 K/s, preferably more than 50 K/s, in order to avoid oxidation in this area of furnace 3 as far as possible.
- a furnace atmosphere with O2 contents of less than 10 ppm, in particular less than 6 ppm, and H2O contents of less than 500 ppm, in particular less than 200 ppm, is preferably set. Furthermore, high H2 contents can be blown into the furnace nozzle 12 in order to achieve good reduction conditions.
- the melt 4 has a temperature T4 of below 620°C. Due to the hot-dip coating below the mentioned temperature T4, the diffusion processes between the melt 4 and the steel strip 2 are relatively short or low, so that a relatively thin pre-diffusion layer is formed.
- FIG. 2 schematically shows a section of a correspondingly pre-coated strip material 2 ′, in which a thin diffusion zone 9 of less than seven micrometers is formed in the transition between substrate 2 and pre-coating 8 .
- the layer thickness of the pre-coating 8 can be adjusted, for example, in such a way that the reduction in the layer thickness due to a downstream production process, such as flexible rolling, is compensated for in order to improve the protection against corrosion.
- the pre-coating 8 On the outside is the pre-coating 8, which can have a minimum thickness of 26 micrometers, in particular at least 34 micrometers, and/or a maximum thickness of 50 micrometers, in particular up to 46 micrometers. With a thickness of the pre-coating of 26 to 50 microns, the coating weight per side of the steel strip is about 78 to 150 g/m 2 .
- the combination of steel substrate 2 with pre-coating is provided with reference number 2'.
- the inductive heating carried out using the above parameters contributes to the creation of a surface that can be coated very well. Together with the low coating temperature of in particular 580 to 620° C., preferably 600 to 610° C., a particularly thin diffusion zone is produced, which then contributes to an improvement in downstream manufacturing processes.
- the coated steel strip 2' can optionally run through a nozzle unit 13, with which excess liquid coating material is blown off the surface.
- a downstream cooling unit 14 the coated steel substrate can be cooled in what is known as an air cooling section.
- the steel strip 2′ can then optionally be skin-passed in a skin-passing unit 15 to improve the surface.
- the skin-passing unit comprises several skin-passing rolls 16, 16'.
- the coated steel substrate 2 ′ can be straightened in a straightening unit 17 by means of a plurality of rollers 18 .
- the coated steel strip 2' can then be coiled into a coil 5' in a coiler 6'.
- FIG. 3 shows a method according to the invention for producing a hardened molded part from a coated steel substrate 2′, which has been produced according to the method described in FIGS.
- the coated steel substrate 2' is flexibly rolled in step S20 by means of a rolling unit 19.
- the coated steel strip 2' which before flexible rolling has a largely constant sheet thickness along its length, is rolled by means of rollers 20, 21 in such a way that it has a variable sheet thickness along the rolling direction.
- the coated and flexibly rolled steel substrate is provided with the reference number 22 .
- the process is monitored and controlled, with the data determined by a sheet thickness measurement 23 being used as an input signal for controlling the rolls 20, 21.
- the flexible rolling is carried out according to the desired target thickness profile of a blank to be cut from the strip material 22 or a component to be produced from it. It can Flexible rollers with rolling rates of at least 1% and/or a maximum of 60% based on the initial thickness of the pre-coated steel substrate 2' are carried out, in particular with rolling rates between 3% and 55%.
- the pre-coating 8 can have a reduced first thickness of in particular less than 20 micrometers in thinner first sections and a reduced second thickness of in particular more than 33 micrometers, preferably more than 36 micrometers in thicker second sections.
- the strip material 22 can be wound up again into the coil 5' so that it can be transported to a subsequent processing station.
- the steel strip 22 can be smoothed in a subsequent process step, which takes place in a strip straightening device 26 .
- the smoothing step is optional and can also be omitted.
- the coated and flexibly rolled steel strip 22 is separated in method step S30.
- individual sheet metal blanks 32 are worked out of the steel strip 22, for example by means of a punching and/or cutting device 24. Depending on the shape of the sheet metal blanks 32 to be produced, these can be punched out of the strip material 22 as a shaped cut, with an edge that is not used being discarded as scrap. or the strip material 22 can simply be cut into sections.
- the blanks 32 which in the initial state at room temperature have a particularly ferritic-pearlitic structure, are hot-formed in a subsequent step S40, which can also be referred to as press hardening.
- a subsequent step S40 which can also be referred to as press hardening.
- the blank 32 is heated to a temperature that is generally above the AC1 or AC3 temperature of the material, for example between 750° C. and 1000° C. Heating may be accomplished by any suitable method, such as inductive heating, conductive heating, roller hearth heating, contact hot plate heating, infrared, or other known methods.
- the initially ferritic-pearlitic structure is at least partially converted into austenite, which is also referred to as austenitizing.
- the holding time for austenitizing the coated blank 32 depends on the selected temperature and can be between 4 and 10 minutes lie. After heating to the austenitization temperature, the blank 32 is then placed in a hot forming tool 25 and shaped therein and cooled or quenched so quickly that at least partially a martensitic hardened structure is produced in the molded part 42 produced in this way.
- hot forming can be carried out as a direct process.
- the blank 32 is heated directly to the austenitization temperature and then hot-formed to the desired final contour in one step.
- a previous (cold) preforming does not take place here.
- hot forming can also be carried out as an indirect process, which includes the partial steps of cold preforming, subsequent heating of the cold preformed component to austenitization temperature and subsequent hot forming to produce the final contour of the molded part.
- the following layers in particular can form from the outside in by way of hot forming: a surface layer 28a, in particular with a proportion of iron of 34 to 45%, aluminum of 50 to 60% and silicon of 5 to 10%; an intermetallic layer, in particular with an iron content of 45 to 60%, aluminum of 25 to 40% and silicon of 10 to 18%; an intermediate layer 28c, in particular with an iron content of 39 to 47%, aluminum of 53 to 61% and silicon of 0 to 2%; and an interdiffusion layer 28d, in particular with a proportion of a-iron or iron of 86 to 95%, aluminum of 4 to 10%, silicon of 0 to 5%, each in percent by weight.
- a surface layer 28a in particular with a proportion of iron of 34 to 45%, aluminum of 50 to 60% and silicon of 5 to 10%
- an intermetallic layer in particular with an iron content of 45 to 60%, aluminum of 25 to 40% and silicon of 10 to 18%
- an intermediate layer 28c in particular with an iron content of 39 to 47%, aluminum of 53 to 61% and silicon
- the coating 28 of the hot worked product 42 in the thinner first portions has a final coating thickness greater than 15 microns, more preferably greater than 20 microns.
- the coating 28 can have a second final thickness, in particular of more than 30 micrometers, preferably more than 35 micrometers.
- the diffusion layer 28d of molding 42 preferably has a thickness of less than 14 microns (14 gm).
- FIG. 5 shows a modified embodiment of a method according to the invention for producing a coated steel substrate.
- the present method largely corresponds to the method according to FIGS. 1 and 2, the description of which is referred to in this respect.
- Identical or mutually corresponding components are provided with the same reference symbols as in the above figures.
- a special feature of the embodiment according to FIG. 5 is that the heating takes place by means of a so-called Sendzimir process, which is particularly suitable for cold-rolled steel strips 2 .
- the heating takes place in a radiant tube furnace 3, which is large enough to recrystallize the material at more than 700° C. for several minutes.
- an atmosphere (hydrogen content, dew point, etc.) and a relatively long annealing time are set such that the surface is sufficiently cleaned to make the steel strip 2 wettable for the coating process.
- the steel strip 2 is heated to the strip target temperature T3 by means of the radiant tube furnace 3, in particular at a heating rate of 10 K/s to 30 K/s.
- the glow time can be more than 120 seconds.
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Abstract
L'invention concerne un procédé de fabrication d'une bande d'acier revêtue, comprenant : le chauffage d'une bande d'acier (2) constituée d'un acier durcissable à une température cible de bande (T3) inférieure à 625 °C, et le revêtement par immersion à chaud de la bande d'acier (2), chauffée à la température cible de bande (T3), dans un bain de fusion (4) qui contient au moins de l'aluminium et du silicium, le bain de fusion (4) ayant une température (T4) inférieure à 620 °C. L'invention concerne également un procédé de production d'un produit en acier trempé à partir du procédé spécifié et une pièce formée à chaud (42) produite à partir de celui-ci.
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DE102020120580.5A DE102020120580A1 (de) | 2020-08-04 | 2020-08-04 | Verfahren zum herstellen von beschichtetem stahlband, und verfahren zum herstellen eines gehärteten stahlprodukts |
PCT/EP2021/071425 WO2022029033A1 (fr) | 2020-08-04 | 2021-07-30 | Procédé de production d'une bande d'acier revêtue, et procédé de production d'un produit d'acier trempé à partir de celle-ci |
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EP0760399B1 (fr) * | 1995-02-24 | 2003-05-14 | Nisshin Steel Co., Ltd. | Tole aluminiee par immersion, son procede de production et dispositif de regulation de la couche d'alliage |
DE102004059566B3 (de) | 2004-12-09 | 2006-08-03 | Thyssenkrupp Steel Ag | Verfahren zum Schmelztauchbeschichten eines Bandes aus höherfestem Stahl |
DE102005013103A1 (de) | 2005-03-18 | 2006-09-28 | Sms Demag Ag | Kontrollierte Dickenreduktion bei schmelztauchbeschichtetem warmgewalztem Stahlband und hierbei eingesetzte Anlage |
EP1826289A1 (fr) | 2006-02-28 | 2007-08-29 | Ocas N.V. | Tôle d'acier revetué avec un revêtement à base d'alumimium et ayant une formabilité amelloreé |
WO2009090443A1 (fr) * | 2008-01-15 | 2009-07-23 | Arcelormittal France | Procédé pour fabriquer des produits estampés, et produits estampés préparés à l'aide de celui-ci |
CN103492600B (zh) | 2011-04-27 | 2015-12-02 | 新日铁住金株式会社 | 热冲压部件用钢板及其制造方法 |
DE102011051731B4 (de) * | 2011-07-11 | 2013-01-24 | Thyssenkrupp Steel Europe Ag | Verfahren zur Herstellung eines durch Schmelztauchbeschichten mit einer metallischen Schutzschicht versehenen Stahlflachprodukts |
DE102016107152B4 (de) * | 2016-04-18 | 2017-11-09 | Salzgitter Flachstahl Gmbh | Bauteil aus pressformgehärtetem, auf Basis von Aluminium beschichtetem Stahlblech und Verfahren zur Herstellung eines solchen Bauteils und dessen Verwendung |
WO2017203314A1 (fr) | 2016-05-24 | 2017-11-30 | Arcelormittal | Tôle d'acier twip ayant une matrice austénitique |
DE102018102624A1 (de) | 2018-02-06 | 2019-08-08 | Salzgitter Flachstahl Gmbh | Verfahren zur Herstellung eines Stahlbandes mit verbesserter Haftung metallischer Schmelztauchüberzüge |
DE102018118015A1 (de) | 2018-07-25 | 2020-01-30 | Muhr Und Bender Kg | Verfahren zur Herstellung eines gehärteten Stahlprodukts |
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2020
- 2020-08-04 DE DE102020120580.5A patent/DE102020120580A1/de active Pending
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2021
- 2021-07-30 WO PCT/EP2021/071425 patent/WO2022029033A1/fr active Application Filing
- 2021-07-30 EP EP21759035.5A patent/EP4192993A1/fr active Pending
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DE102020120580A1 (de) | 2022-02-10 |
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