EP3504349A1 - Method for producing a high-strength steel strip with improved properties for further processing, and a steel strip of this type - Google Patents
Method for producing a high-strength steel strip with improved properties for further processing, and a steel strip of this typeInfo
- Publication number
- EP3504349A1 EP3504349A1 EP17757729.3A EP17757729A EP3504349A1 EP 3504349 A1 EP3504349 A1 EP 3504349A1 EP 17757729 A EP17757729 A EP 17757729A EP 3504349 A1 EP3504349 A1 EP 3504349A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- strip
- steel strip
- rolling
- steel
- hot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 96
- 239000010959 steel Substances 0.000 title claims abstract description 96
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 12
- 238000012545 processing Methods 0.000 title abstract description 9
- 238000005096 rolling process Methods 0.000 claims abstract description 30
- 238000000137 annealing Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 24
- 230000000694 effects Effects 0.000 claims abstract description 23
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000005266 casting Methods 0.000 claims abstract description 16
- 238000005098 hot rolling Methods 0.000 claims abstract description 15
- 238000005097 cold rolling Methods 0.000 claims abstract description 13
- 238000005246 galvanizing Methods 0.000 claims abstract description 12
- 229910052742 iron Inorganic materials 0.000 claims abstract description 11
- 238000000576 coating method Methods 0.000 claims abstract description 10
- 239000011248 coating agent Substances 0.000 claims abstract description 8
- 230000008569 process Effects 0.000 claims abstract description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 7
- 238000002844 melting Methods 0.000 claims abstract description 5
- 230000008018 melting Effects 0.000 claims abstract description 5
- 239000000161 steel melt Substances 0.000 claims abstract description 5
- 238000005554 pickling Methods 0.000 claims abstract description 3
- 238000009489 vacuum treatment Methods 0.000 claims abstract description 3
- 229910001566 austenite Inorganic materials 0.000 claims description 20
- 229910052748 manganese Inorganic materials 0.000 claims description 16
- 229910000734 martensite Inorganic materials 0.000 claims description 16
- 229910045601 alloy Inorganic materials 0.000 claims description 14
- 239000000956 alloy Substances 0.000 claims description 14
- 238000005242 forging Methods 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- 229910001563 bainite Inorganic materials 0.000 claims description 5
- 238000011282 treatment Methods 0.000 claims description 5
- 229910000859 α-Fe Inorganic materials 0.000 claims description 5
- 229910000922 High-strength low-alloy steel Inorganic materials 0.000 claims description 2
- 239000000470 constituent Substances 0.000 claims description 2
- 238000001816 cooling Methods 0.000 claims description 2
- 238000010891 electric arc Methods 0.000 claims description 2
- 239000000203 mixture Substances 0.000 claims description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 claims 1
- 239000008397 galvanized steel Substances 0.000 claims 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 12
- 229910052739 hydrogen Inorganic materials 0.000 abstract description 12
- 239000001257 hydrogen Substances 0.000 abstract description 12
- 230000003111 delayed effect Effects 0.000 abstract description 7
- 229910001338 liquidmetal Inorganic materials 0.000 abstract description 5
- 239000000155 melt Substances 0.000 abstract description 4
- 238000009434 installation Methods 0.000 abstract 1
- 239000011572 manganese Substances 0.000 description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 12
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 12
- 239000000047 product Substances 0.000 description 10
- 238000005275 alloying Methods 0.000 description 8
- 239000010936 titanium Substances 0.000 description 8
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 7
- 229910052698 phosphorus Inorganic materials 0.000 description 7
- 239000011574 phosphorus Substances 0.000 description 7
- 239000011651 chromium Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 6
- 229910000617 Mangalloy Inorganic materials 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000005336 cracking Methods 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 230000035882 stress Effects 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- 229910000794 TRIP steel Inorganic materials 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000032683 aging Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 230000000717 retained effect Effects 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 239000011573 trace mineral Substances 0.000 description 2
- 235000013619 trace mineral Nutrition 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910000937 TWIP steel Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000003679 aging effect Effects 0.000 description 1
- -1 aluminum nitrides Chemical class 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 150000002696 manganese Chemical class 0.000 description 1
- KQFUCKFHODLIAZ-UHFFFAOYSA-N manganese Chemical compound [Mn].[Mn] KQFUCKFHODLIAZ-UHFFFAOYSA-N 0.000 description 1
- 238000011089 mechanical engineering Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229910001562 pearlite Inorganic materials 0.000 description 1
- 239000006223 plastic coating Substances 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000005482 strain hardening Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 230000003245 working effect Effects 0.000 description 1
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
- C21D8/0221—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
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
-
- 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
-
- 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
- C21D8/0236—Cold rolling
-
- 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
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
-
- 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
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
-
- 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
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
Definitions
- the invention relates to a method for producing a high-strength steel strip with improved properties during further processing and to a corresponding steel strip.
- the invention relates to the production of a steel strip from a manganese-containing TRANS (TRANSFORMED INDUCED PLASTICITY) and / or TWIP (TWinning Induced Plasticity) steel with excellent cold and warm forging, increased resistance to hydrogen-induced delayed fracture, to hydrogen embrittlement (US Pat. hydrogen embrittlement) as well as liquid metal embrittlement during welding.
- European Patent Application EP 2 383 353 A2 discloses a manganese-containing steel, a flat steel product of this steel and a method for producing this flat steel product.
- the steel has a tensile strength of 900 to 1500 MPa and an elongation at break A80 of at least 4%. The highest described elongation at break A80 is 8%.
- the steel consists of the elements (contents in percent by weight and based on the molten steel): C: up to 0.5; Mn: 4 to 12.0; Si: up to 1, 0; AI: up to 3.0; Cr: 0.1 to 4.0; Cu: up to 4.0; Ni: up to 2.0; N: up to 0.05; P: up to 0.05; S: up to 0.01; as well as residual iron and unavoidable impurities.
- one or more elements from the group "V, Nb, Ti" are provided, the sum of the contents of these elements being at most equal to 0.5, for a Mn content of 5 and an Al content of 2 the sum is included 7.
- the structure of this flat steel product consists of 30 to 100% martensite, tempered martensite or bainite, balance austenite, which is said to be more cost effective to produce than steel
- a method for producing a steel flat product from the above-described high-strength manganese-containing steel comprising the following steps: - melting the above-described molten steel, - producing a starting product for subsequent hot rolling, by the molten steel to a strand, of the at least one slab or thin slab as the starting material for the Hot rolling is divided, or cast into a cast strip, which is fed as a starting product to the hot rolling, - heat treating the
- Starting product to bring the starting material to a hot rolling starting temperature of 1 150 to 1000 ° C, - hot rolling of the starting product to a
- Hot strip of not more than 2,5 mm thick finishing hot rolling at a hot rolling end temperature of 1050 to 800 ° C, - coiling the hot strip into a coil at a coiler temperature of ⁇ 700 ° C.
- the hot strip can be annealed at 250 to 950 ° C, then cold rolled and annealed again at 450 to 950 ° C. Also, following the cold or
- Corrosion protection coating or an organic coating provided.
- TRIP steel Can convert martensite (TRIP effect).
- the manganese content of the steel strip is 1.00 to 2.25 weight percent.
- the steel strip is coated and dressed in a molten bath. Because of its high work hardening, the TRIP steel achieves high levels of uniform elongation and tensile strength.
- TRIP steels u. a. in structural, chassis and crash-relevant components of vehicles, as sheet metal blanks, as well as welded blanks.
- European patent EP 1 067 203 B1 discloses a method for producing a steel strip.
- the thin strip is hot rolled to a degree of reduction of between 10% and 60%, acid pickled, cold rolled to a degree of reduction of between 10% and 90% and recrystallized for 1 to 2 minutes at 800 to 850 ° C.
- Japanese Patent JP 3 317 303 B2 discloses a high-strength steel strip which has the following composition in percent by weight: C: 0.05-0.3; Si: ⁇ 0.2; Mn: 0.5-4.0: P: ⁇ 0.1; S: ⁇ 0.1; Ni: 0 - 5.0; Al: 0.1-2.0 and N ⁇ 0.01.
- C 0.05-0.3
- Si ⁇ 0.2
- Mn 0.5-4.0
- P ⁇ 0.1
- S ⁇ 0.1
- Ni 0 - 5.0
- Al 0.1-2.0 and N ⁇ 0.01.
- Si + Al 0.5; Mn + 1/3 Ni> 1, 0.
- a melt of the above-described steel is melted. By warm forging is a
- Test block produced with a thickness of 25 mm. This is then heated to 1250 ° C in an electric oven for one hour. Subsequently, hot rolling is carried out at 930-1,150 ° C to obtain a steel strip thickness of 5 mm. For a coiler simulation, the steel strip is immediately cooled to 500 ° C and annealed in an electric oven at this temperature for one hour.
- the present invention based on the object to provide a method for producing a high-strength steel strip of a manganese-containing TRIP and / or TWIP steel with strengths between 1 100 and 2200 MPa, which is inexpensive and wherein the steel strip improved
- This object is achieved by a method for producing a flat steel product, in particular using the aforementioned steel, having the features of claim 1 and by a very high strength steel strip having the features of
- According to the invention provides a method for producing a high-strength
- Steel strip comprising the steps of: melting a steel melt containing (in% by weight): C: 0.1 to ⁇ 0.3; Mn: 4 to ⁇ 8; AI:> 1 to 2.9; P: ⁇ 0.05; S: ⁇ 0.05; N: ⁇ 0.02; Remainder of iron, including unavoidable steel-supporting elements, with optional addition of one or more of the following elements (in
- Weight%) Si: 0.05 to 0.7; Cr: 0.1 to 3; Mo: 0.01 to 0.9; Ti: 0.005 to 0.3; B: 0.0005 to 0.01 over the process route blast furnace steel mill or the
- Electric arc furnace process each with optional vacuum treatment of the melt; - Pouring the molten steel to a Vorband by means of a close to the final dimension horizontal or vertical Bandg intelligentvons or casting the molten steel to a slab or thin slab by means of a horizontal or vertical slab or thin slab casting process, heating to a rolling temperature of 1050 to 1250 ° C or inline rolling from the casting heat, hot rolling the sliver or slab or slab into a hot strip having a thickness of 12 to 0.8 mm, with a rolling end temperature of 1050 to 800 ° C, - coiling of the hot strip at a temperature of more than 200 to 800 ° C, - pickling of the hot strip, - annealing of the hot strip in a continuous or discontinuous annealing at a Glow time from 1 min to 48 h and
- Hydrogen embrittlement and liquid metal embrittlement which additionally has a TRIP and / or TWIP effect under mechanical stress.
- Typical thickness ranges for pre-strip are 1 mm to 35 mm and for slabs and thin slabs 35 mm to 450 mm.
- the slab or thin slab is hot rolled to a hot strip having a thickness of 12 mm to 0.8 mm, or the final near cast cast slab is hot rolled to a hot strip with a thickness of 8 mm to 0.8 mm.
- Cold strip according to the invention has a thickness of at most 3 mm, preferably 0.1 to 1, 4 mm.
- Hot rolling thus already takes place inline during the two-roll casting process, so that separate heating and hot rolling can optionally be dispensed with.
- the cold rolling of the hot strip can at room temperature or advantageous at elevated temperature before the first rolling pass in one or more rolling passes take place.
- Cold rolling at elevated temperature is advantageous to reduce rolling forces and promote the formation of twinned twins (TWIP effect).
- Advantageous temperatures of the rolling stock before the first pass are 60 to 450 ° C.
- the steel strip to restore sufficient forming properties is advantageous in a continuous annealing, in particular continuous annealing, advantageously at a glow time of 1 to 15 minutes and temperatures of 720 ° C to 840 ° C for annealing.
- the steel strip is advantageously cooled to a temperature of 250 ° C to room temperature and then, if necessary, to adjust the required mechanical properties in the course of a
- the aging treatment can advantageously be carried out in a continuous annealing plant.
- the steel strip can be dressed after cold rolling, thereby adjusting the surface texture needed for the end use.
- the casting can be done for example by means of the Pretex® method.
- the steel strip thus produced receives instead of or after the electrolytic galvanizing or hot-dip galvanizing another coating on an organic or inorganic basis.
- coatings may be, for example, organic coatings, plastic coatings or paints or otherwise
- inorganic coatings such as iron oxide layers.
- the steel strip produced according to the invention can be used both as a sheet metal, sheet metal section or plate or further processed to form a longitudinally welded or spiral seam welded tube.
- the steel sheet or steel strip is particularly advantageous for further processing to a component by cold or warm forging, for example in the automotive industry, in infrastructure and mechanical engineering.
- the steel strip with improved properties during further processing has a TRIP / TWIP effect, with a structure (in volume%) of 10 to 80% austenite, 10 to 90% martensite, remainder ferrite and bainite with a share of less than 20%.
- at least 20% of the martensite is present as tempered martensite and optionally a proportion of> 10% of the austenite in the form of annealing or deformation twins.
- the steel strip has a particularly fine grain with a mean grain size of the phase constituents:
- Martensite, ferrite, bainite less than 650 nm.
- the austenite Due to the final annealing of the cold strip produced at room temperature or at elevated temperatures, the austenite is in a metastable state and optionally with twins, whereby it partially converts to martensite under mechanical force (eg, forming) by TRIP effect.
- the austenite part of the steel according to the invention can partially or completely convert into martensite when mechanical stresses are applied (TRIP effect).
- the alloy according to the invention has corresponding mechanical properties
- TWIP effect Stress also a twinning in plastic deformation on (TWIP effect). Because of the strong induced by the TRIP and / or TWIP effect
- Hardening the steel achieved high levels of elongation at break, in particular to uniform elongation, and tensile strength.
- Annealing can be done advantageously by means of a continuous annealing, which is much more economical compared to a Haubenglühung.
- a steel strip produced by the process according to the invention advantageously has a yield strength Rp0.2 of 300 to 1550 MPa, a tensile strength Rm of 1100 to 2200 MPa and an elongation at break A80 of more than 4 to 41%, with high strengths tending to be associated with lower elongations at break and vice versa: Rm of more than 1 100 to 1200 MPa: Rm x A80> 25000 to 45000 MPa% Rm from over 1200 to 1400 MPa: Rm x A80> 20000 up to 42000 MPa% Rm over 1400 to 1800 MPa: Rm x A80> 10000 up to 40000 MPa% Rm over 1800 MPa: Rm x A80> 7200 up to 20000 MPa% For the elongation at break tests, a specimen A80 was used according to DIN 50 125.
- the elongation and toughness properties are advantageously improved by the onset of TRIP and / or TWIP effect of the alloy according to the invention.
- the steel strip produced according to the invention offers a good combination of
- this manganese-containing manganese steel of the present invention (medium manganese steel) based on the alloying elements C, Mn, Al is very high
- the manganese steel according to the invention is also distinguished by an increased resistance to delayed fracture and to hydrogen embrittlement and liquid metal embrittlement during welding.
- the use of the term "bis" in the definitions of the content ranges, such as 0.01 to 1 wt .-% means that the benchmarks - in the example 0.01 and 1 - are included.
- Alloying elements are usually added to the steel in order to specifically influence certain properties.
- An alloying element in different steels can influence different properties. The effect and interaction generally depends strongly on the amount, the presence of other alloying elements and the dissolution state in the material.
- Carbon C needed to form carbides, stabilizes austenite and increases strength. Higher contents of C deteriorate the welding properties and lead to the deterioration of the elongation and toughness properties, therefore, a maximum content of less than 0.3 wt% is determined. In order to achieve sufficient strength of the material, a minimum addition of 0.1 wt .-% is required.
- Manganese Mn Stabilizes austenite, increases strength and toughness, and allows for strain-induced martensite and / or twin formation in the alloy of the present invention. Contents less than 4% by weight are insufficient to stabilize the austenite and thus worsen the elongation properties, while at contents of 8% by weight and more, the austenite is excessively stabilized and thereby the strength properties, in particular the 0.2% proof stress, be reduced. For manganese manganese according to the invention with medium
- Aluminum Al In manganese content, a range of 4 to ⁇ 8% by weight is preferred.
- Aluminum Al An Al content of more than 1 wt% improves strength and elongation properties, lowers specific gravity, and affects
- Transformation behavior of the alloy according to the invention Al contents of more than 2.9% by weight deteriorate the elongation properties. Also, higher Al contents significantly worsen the casting behavior in continuous casting. This results in a higher cost when casting. Al contents of more than 1% by weight delay the precipitation of carbides in the alloy according to the invention. Therefore, a maximum content of 2.9 wt .-% and a minimum content of more than 1 wt .-% is set. Furthermore, for the sum of Mn and Al, a minimum content (in% by weight) greater than 6.5 and less than 10 should be maintained to achieve the desired
- a content of Mn + Al of 10% by weight or more deteriorates the castability, thereby decreasing the yield and thus increasing the cost.
- contents of Mn + Al of 6.5% by weight or less sufficient austenite stability for the desired Conversion behavior can be ensured.
- Silicon Si The optional addition of Si at levels greater than 0.05 wt% hinders carbon diffusion, reduces specific gravity, and increases strength and elongation and toughness properties. Furthermore, an improvement in cold rollability by alloying Si could be observed. Contents of more than 0.7 wt .-% lead to embrittlement of the material and affect the hot and cold rollability and coatability
- Chromium Cr The optional addition of Cr improves strength and reduces corrosion rate, retards ferrite and pearlite formation, and forms carbides.
- the maximum content is set at 3% by weight, since higher contents are one
- Efficacy Minimum Cr content is set at 0.1% by weight.
- Molybdenum Mo acts as a carbide former, increasing strength and increasing resistance to delayed cracking and hydrogen embrittlement. Contents of Mo of more than 0.9 wt .-% worsen the
- Phosphorus P is a trace element from iron ore and is found in iron lattice as
- the sulfur content is limited to values less than 0.05 wt .-%.
- Nitrogen N Is also an accompanying element of steelmaking. In the dissolved state, it improves the strength and toughness properties of steels containing more than 4 manganese by weight of manganese containing more than or equal to 4% by weight. Low Mn-alloyed steels of less than 4 wt% with free nitrogen tend to have a strong aging effect. The nitrogen diffuses at low temperatures at dislocations and blocks them. It causes an increase in strength combined with a rapid loss of toughness. A bonding of the nitrogen in the form of nitrides, for example, by alloying of aluminum or titanium possible, with particular aluminum nitrides negative on the
- the nitrogen content is limited to less than 0.02 wt .-%.
- Titanium Ti As a carbide former, it refines grain, improving its strength, toughness, and elongation properties while reducing intergranular corrosion. Contents of Ti exceeding 0.3% by weight deteriorate the elongation properties, therefore, a maximum content of Ti of 0.3% by weight is set. Optionally, a minimum content of 0.005 is set to bind nitrogen and advantageously precipitate Ti.
- Boron B Delays the austenite transformation, improves the hot working properties of steels and increases the strength at room temperature. It unfolds its effect even at very low alloy contents. Contents above 0.01% by weight greatly deteriorate the elongation and toughness properties, and therefore the maximum content is set to 0.01% by weight. Optionally, a minimum level of 0.0005% by weight is set to take advantage of the strength-enhancing effect of boron.
- alloy 1 contains in part the following elements in the listed contents in% by weight:
- the steel strips made from the aforementioned alloy 1 were cold rolled for comparison, i. at room temperature and thus below 50 ° C, and also rolled according to the invention at 250 ° C.
- the measured rolling forces are given below:
- Cumulative rolling force is understood to mean adding up the rolling forces of the individual passes in order to obtain a comparable measure of the force required.
- the rolling force was standardized to a bandwidth of 1000 mm.
- the degree of deformation e is defined as the quotient of the change in thickness Ad of the steel strip examined by the initial thickness dO of the steel strip examined.
- the rolling force reduction is the calculated reduction in rolling force at 250 ° C as compared with the cold rolling force.
Abstract
Description
Claims
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DE102016115618.3A DE102016115618A1 (en) | 2016-08-23 | 2016-08-23 | Process for producing a high-strength steel strip with improved properties during further processing and such a steel strip |
DE102016121002 | 2016-11-03 | ||
PCT/EP2017/070913 WO2018036918A1 (en) | 2016-08-23 | 2017-08-18 | Method for producing a high-strength steel strip with improved properties for further processing, and a steel strip of this type |
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EP (1) | EP3504349B1 (en) |
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US11285529B2 (en) | 2018-04-24 | 2022-03-29 | Nucor Corporation | Aluminum-free steel alloys and methods for making the same |
CN108998741B (en) * | 2018-05-29 | 2020-02-14 | 西南交通大学 | Ultrahigh-strength toughness medium manganese transformation induced plasticity steel and preparation method thereof |
WO2021089851A1 (en) * | 2019-11-08 | 2021-05-14 | Ssab Technology Ab | Medium manganese steel product and method of manufacturing the same |
CN111621624B (en) * | 2020-05-11 | 2021-10-22 | 北京交通大学 | Process method for improving hydrogen-induced delayed fracture resistance of medium manganese steel |
CN111850410B (en) * | 2020-07-30 | 2022-02-15 | 吉林建龙钢铁有限责任公司 | Cold-hard coiled plate for packing belt and preparation method thereof |
CN112226679B (en) * | 2020-09-14 | 2022-06-21 | 包头钢铁(集团)有限责任公司 | Cold-rolled 980 MPa-grade martensitic steel and production method thereof |
CN114606430B (en) * | 2022-03-01 | 2023-05-12 | 兴机电器有限公司 | Low-carbon Fe-Mn-Al-Si TWIP steel and preparation method thereof |
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JP3317303B2 (en) | 1991-09-17 | 2002-08-26 | 住友金属工業株式会社 | High tensile strength thin steel sheet with excellent local ductility and its manufacturing method |
FR2796083B1 (en) | 1999-07-07 | 2001-08-31 | Usinor | PROCESS FOR MANUFACTURING IRON-CARBON-MANGANESE ALLOY STRIPS, AND STRIPS THUS PRODUCED |
KR101027250B1 (en) * | 2008-05-20 | 2011-04-06 | 주식회사 포스코 | High strength steel sheet and hot dip galvanized steel sheet having high ductility and excellent delayed fracture resistance and method for manufacturing the same |
JP5287770B2 (en) * | 2010-03-09 | 2013-09-11 | Jfeスチール株式会社 | High strength steel plate and manufacturing method thereof |
EP2383353B1 (en) | 2010-04-30 | 2019-11-06 | ThyssenKrupp Steel Europe AG | High tensile steel containing Mn, steel surface product made from such steel and method for producing same |
JP5397569B2 (en) * | 2011-04-21 | 2014-01-22 | 新日鐵住金株式会社 | High strength cold-rolled steel sheet excellent in uniform elongation and hole expansibility and method for producing the same |
DE102012013113A1 (en) | 2012-06-22 | 2013-12-24 | Salzgitter Flachstahl Gmbh | High strength multiphase steel and method of making a strip of this steel having a minimum tensile strength of 580 MPa |
CN102758133B (en) * | 2012-07-26 | 2013-12-25 | 宝山钢铁股份有限公司 | 1000MPa-level automobile steel with high product of strength and elongation and manufacturing method thereof |
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KR101749201B1 (en) * | 2013-05-06 | 2017-06-20 | 잘쯔기터 플래시슈탈 게엠베하 | Method for producing components from lightweight steel |
WO2015011510A1 (en) * | 2013-07-25 | 2015-01-29 | Arcelormittal Investigación Y Desarrollo Sl | Spot welded joint using high strength and high forming and its production method |
DE102015112889A1 (en) * | 2015-08-05 | 2017-02-09 | Salzgitter Flachstahl Gmbh | High-strength manganese-containing steel, use of the steel for flexibly rolled flat steel products and production methods together with flat steel product for this purpose |
CN109072371B (en) * | 2016-01-29 | 2020-08-21 | 杰富意钢铁株式会社 | High-strength steel sheet for warm working and method for producing same |
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US20210147953A1 (en) | 2021-05-20 |
WO2018036918A1 (en) | 2018-03-01 |
EP3504349B1 (en) | 2024-04-03 |
CN109642263A (en) | 2019-04-16 |
US20190185951A1 (en) | 2019-06-20 |
KR102401569B1 (en) | 2022-05-23 |
CN109642263B (en) | 2021-02-26 |
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RU2714975C1 (en) | 2020-02-21 |
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