EP4247993A1 - Bauteil aus b-zr-legiertem stahl - Google Patents
Bauteil aus b-zr-legiertem stahlInfo
- Publication number
- EP4247993A1 EP4247993A1 EP22826100.4A EP22826100A EP4247993A1 EP 4247993 A1 EP4247993 A1 EP 4247993A1 EP 22826100 A EP22826100 A EP 22826100A EP 4247993 A1 EP4247993 A1 EP 4247993A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- steel
- weight
- component
- depth
- content
- 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 166
- 239000010959 steel Substances 0.000 title claims abstract description 166
- 229910001093 Zr alloy Inorganic materials 0.000 title 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000012535 impurity Substances 0.000 claims abstract description 19
- 229910052726 zirconium Inorganic materials 0.000 claims abstract description 17
- 229910052719 titanium Inorganic materials 0.000 claims abstract description 14
- 229910052720 vanadium Inorganic materials 0.000 claims abstract description 12
- 229910052742 iron Inorganic materials 0.000 claims abstract description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 9
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 9
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 8
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 8
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims description 20
- 238000005496 tempering Methods 0.000 claims description 15
- 229910052750 molybdenum Inorganic materials 0.000 claims description 13
- 239000000203 mixture Substances 0.000 claims description 12
- 229910052759 nickel Inorganic materials 0.000 claims description 12
- 229910052791 calcium Inorganic materials 0.000 claims description 10
- 238000000034 method Methods 0.000 claims description 10
- 238000005096 rolling process Methods 0.000 claims description 10
- 229910052718 tin Inorganic materials 0.000 claims description 10
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229910000734 martensite Inorganic materials 0.000 claims description 6
- 230000000930 thermomechanical effect Effects 0.000 claims description 6
- 229910052787 antimony Inorganic materials 0.000 claims description 5
- 229910052785 arsenic Inorganic materials 0.000 claims description 5
- 229910052797 bismuth Inorganic materials 0.000 claims description 5
- 229910052747 lanthanoid Inorganic materials 0.000 claims description 5
- 150000002602 lanthanoids Chemical class 0.000 claims description 5
- 229910052745 lead Inorganic materials 0.000 claims description 5
- 229910052758 niobium Inorganic materials 0.000 claims description 5
- 150000003839 salts Chemical class 0.000 claims description 5
- 229910052711 selenium Inorganic materials 0.000 claims description 5
- 229910052714 tellurium Inorganic materials 0.000 claims description 5
- 229910052721 tungsten Inorganic materials 0.000 claims description 5
- 229910052684 Cerium Inorganic materials 0.000 claims description 4
- 229910052715 tantalum Inorganic materials 0.000 claims description 4
- 238000005491 wire drawing Methods 0.000 claims description 2
- 229910052796 boron Inorganic materials 0.000 abstract description 23
- 229910052799 carbon Inorganic materials 0.000 abstract description 3
- 229910052748 manganese Inorganic materials 0.000 abstract description 2
- 229910052804 chromium Inorganic materials 0.000 abstract 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 19
- 239000010936 titanium Substances 0.000 description 11
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 8
- 238000005275 alloying Methods 0.000 description 8
- 229910052739 hydrogen Inorganic materials 0.000 description 8
- 239000001257 hydrogen Substances 0.000 description 8
- 238000000137 annealing Methods 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 6
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 5
- 239000000470 constituent Substances 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 229910052735 hafnium Inorganic materials 0.000 description 4
- 229910001567 cementite Inorganic materials 0.000 description 3
- KSOKAHYVTMZFBJ-UHFFFAOYSA-N iron;methane Chemical compound C.[Fe].[Fe].[Fe] KSOKAHYVTMZFBJ-UHFFFAOYSA-N 0.000 description 3
- 238000001000 micrograph Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 3
- 229910000521 B alloy Inorganic materials 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229910001566 austenite Inorganic materials 0.000 description 2
- 229910052729 chemical element Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910001562 pearlite Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- GNFTZDOKVXKIBK-UHFFFAOYSA-N 3-(2-methoxyethoxy)benzohydrazide Chemical compound COCCOC1=CC=CC(C(=O)NN)=C1 GNFTZDOKVXKIBK-UHFFFAOYSA-N 0.000 description 1
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 description 1
- 229910017112 Fe—C Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 238000001636 atomic emission spectroscopy Methods 0.000 description 1
- 238000000889 atomisation Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000001336 glow discharge atomic emission spectroscopy Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 150000001247 metal acetylides Chemical class 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 229910021332 silicide Inorganic materials 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000009466 transformation Effects 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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0093—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for screws; for bolts
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/06—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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- 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
- 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
- C21D2211/002—Bainite
-
- 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
- C21D2211/005—Ferrite
-
- 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
-
- 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
- C21D2211/009—Pearlite
Definitions
- the invention relates to a component with a component made of steel, in which the steel is alloyed with boron (hereinafter also "B"), among other things.
- B boron
- the invention relates to a fastener such as a screw or a nut.
- boron is often used as a cost-effective alloying element to improve through-hardenability.
- Steels alloyed with boron are described, for example, in WO 2021/009705 A1 and WO 2008/142275 A2.
- components made of boron-alloyed steels such as screws or nuts, often show a drop in hardness in the edge area after heat treatment, in particular isothermal heat treatment in a salt bath to set a bainitic structure, in particular down to a depth of up to 300 ⁇ m below the surface , which limits the applicability for high-strength and ultra-high-strength products such as high-strength and ultra-high-strength bolts.
- Steels that contain boron are usually additionally alloyed with titanium and aluminum in order to keep boron in the dissolved state and not precipitate in the form of nitrides, carbides, carbonitrides, silicides or oxides.
- This is not sufficient to reduce the hardness inhomogeneity in the edge area described above.
- the object of the present invention is therefore to reduce the drop in hardness in the edge region of components made of boron-alloyed steels.
- One aspect of the invention relates to a component with a component made of steel, the steel
- a further aspect of the invention relates to a method for producing a component with a component made of steel, comprising the steps:
- the composition according to the invention in particular the zirconium added to the B-containing steel in combination with the other alloying elements in the component according to the invention with a component made of steel, counteracts the decrease in hardness in the edge area, especially if the component made of steel is heat-treated.
- Another surprising advantage of the component according to the invention with a component made of steel is the improved resistance to hydrogen embrittlement. Surprisingly, significantly higher strengths can be achieved in this way.
- the invention can thus also relate to a vehicle, an engine, a cylinder head, a chassis arrangement or a battery arrangement with a component according to the invention, in particular a fastening means.
- the component has a steel component, the steel consisting of the following components: 0.30-0.50% by weight C, 0.05-1.3% by weight Mn, 0.001-0.015 wt% P,
- each impurity is preferably contained in ⁇ 0.01% by weight.
- the steel can be optional
- the invention relates to a component with a component made of steel, the steel
- the steel preferably consists of the components mentioned above. Each impurity is preferably contained in ⁇ 0.01% by weight.
- the invention relates to a component with a steel component, the steel containing 0.30-0.46% by weight C, 0.3-1.3% by weight Mn, 0.001-0.015% by weight -% P, 0.001 - 0.015% by weight S, 0.01 - 0.60% by weight Si, 0.3 - 1.3% by weight Cr, 0.005 - 0.35% by weight V, 0.0012 - 0.0050 wt% B, 0.02 - 0.25 wt% Al, 0.0020 - 0.0150 wt% N, 0.014 - 0.060 wt% Ti, and 0 .0050 - 0.0500 wt% Zr; optional
- the steel preferably consists of the components mentioned above.
- Each impurity is preferably contained in ⁇ 0.01% by weight.
- a component comprising steel, the steel comprising 0.34-0.42 wt.% C, 0.45-0.90 wt.% Mn, 0.001-0.015 wt% P, 0.001 - 0.015 wt% S,
- the steel preferably consists of the components mentioned above.
- Each impurity is preferably contained in ⁇ 0.01% by weight.
- the steel according to the above compositions can also be optional
- a component with a component made of steel is preferred, the steel
- 0.01-0.04 wt% As, 0.01-0.02 wt% Sn, 0.01-0.20 wt% Ta, 0.01-0.20 wt% Ce, 0.01-0.50 wt% Sn, 0.01-0.40 wt% Sb, 0.01-0.20 wt% Hf, and/or one or more lanthanides, respectively in an amount of 0.01-0.02% by weight, the balance iron and unavoidable impurities, preferably consists of these components, each impurity being ⁇ 0.01% by weight.
- the drop in hardness in the edge area of the components can be reduced particularly effectively.
- the hydrogen embrittlement of the steel is greatly reduced.
- the components Mo, Ni, Cu and Ca are optional, ie they may not be included independently of one another or, if they are included, they may be included independently of one another in the specified amounts of, for example, 0.01-0.20% by weight Mo, 0.01 - 0.50% by weight Ni, 0.01 - 0.50% by weight Cu and/or 0.0010 - 0.0100% by weight Ca in the steel.
- the components Mo, Ni, Cu and Ca are contained in the steel independently of one another.
- the steel contains 0.01 - 0.20 wt% Mo, 0.01 - 0.50 wt% Ni, 0.01 - 0.50 wt% Cu and/or 0 0.0010 - 0.0100% by weight Ca, more preferably 0.01 - 0.16% by weight Mo, 0.01 - 0.40% by weight Ni, 0.01 - 0.30% by weight -% Cu and/or 0.0010 - 0.0080% by weight Ca.
- the components Bi, Co, Nb, Pb, Se, Te, W, As, Sn, Ta, Ce, Sn, Sb, Hf and/or lanthanides can also optionally be contained in the steel, ie they can be contained independently of one another or not be included. If they are contained, they can preferably be contained independently of one another in the stated amounts.
- zirconium is a micro-alloying element, i.e. it has an effect even in very small amounts, in particular even below 0.05% by weight.
- Boron, titanium and vanadium are also micro-alloying elements.
- the zirconium acts in conjunction with the other alloying elements, for example the vanadium.
- the B content in the steel at a depth of 5-60 ⁇ m is >80%, preferably >90%, of the B content in the steel at a depth of 500 ⁇ m (micrometers), the depth being measured perpendicularly to the steel surface.
- the B content at any location at a depth of 5 - 60 microns is > 80% of the B content in the steel at a depth of 500 microns.
- the minimum B content in the steel at a depth of 5-60 ⁇ m is >80% of the boron content in the steel at a depth of 500 ⁇ m, preferably >90%, particularly preferred > 95%.
- B content is meant the concentration of boron in percent by weight based on the total weight of the steel. Since the value of >80%, for example, is a relative value of two B contents in each case, the B content does not have to be in weight percent, but can also be specified in volume or atomic percent, for example.
- the B content is determined by means of GDOES (glow discharge optical emission spectroscopy, optical glow discharge spectroscopy) (equipment: GDA 750 HR from Spectruma Analytik GmbH).
- GDOES low discharge optical emission spectroscopy, optical glow discharge spectroscopy
- the surface of the sample material (steel), the sample atoms, is removed with the aid of an Ar plasma are brought into the gas phase (cathode atomization or sputtering) and quantitatively determined there spectroscopically.
- the B content is measured spectroscopically at every depth, for example over a depth range of 0 - 500 pm.
- a so-called B depth profile is produced as the measurement result.
- the B content is determined at every depth, for example over the range of 0 - 500 pm depth.
- the ratio is then determined via the quotient of the B content at a specific depth (for example 10 ⁇ m) and at a depth of 500 ⁇ m, and the percentage value is thus determined, which according to the invention
- the boron content in the steel at a depth of 140-220 ⁇ m is additionally >80% of the boron content in the steel at a depth of 500 ⁇ m.
- the boron content is independently preferably >90%, more preferably >95%, more preferably >98%, even more preferably >100%, most preferably 100-1000% of the boron content of the steel at a depth of 500 ⁇ m, the depth being measured perpendicular to the steel surface.
- the boron content (B concentration) in the steel at a depth of 5 - 60 ⁇ m is 0.0030 - 0.0033 wt% and at a depth of 500 ⁇ m is 0.0033 wt% the 90.9% - 100%.
- the other chemical elements of the steel are measured as usual with a classic optical emission spectrometry on the surface of a cross section of the steel component (so-called piece analysis).
- the given percentages by weight of the chemical elements of the steel are in each case based on the total weight of the steel.
- the heat treatment or tempering at the end of the manufacturing process in particular salt bath tempering, which leads to these advantageous properties in the edge region of the steel component in the component according to the invention, is advantageous for the small or non-existent drop in the boron concentration .
- the edge area is understood to mean in particular the area at a depth of 0 - 300 micrometers, measured from the steel surface.
- the zirconium in particular, in combination with the other alloying elements, counteracts the drop in hardness in the edge area and leads to a reduction in hydrogen embrittlement in the edge area.
- an impurity is understood to mean an element that is present in an amount of ⁇ 0.01% by weight.
- the steel therefore preferably comprises unavoidable impurities, in each case in an amount of ⁇ 0.01% by weight.
- the drop in hardness in the edge area of the components can be reduced particularly effectively if the ratio of (Zr+Ti+Al) to N is in a range from 2.7 to 150, more preferably 2.8 to 130, particularly preferably 3 to 100.
- the respective percentages by weight of Zr, Ti, Al and N are used in the above formula.
- the component according to the invention with a component made of steel is preferably a fastening means, particularly preferably selected from the group consisting of screws, nuts, rivets, bolts and chains.
- a component made of steel within the meaning of the invention can be understood in particular as meaning that at least part of the component, i.e. a volume area, is made of steel. It is preferred that the steel component accounts for >80% by weight, more preferably >90% by weight, particularly preferably >95% by weight of the component. This means that >80% by weight, more preferably >90% by weight, particularly preferably >95% by weight of the component consists of steel. As a result, a particularly good mechanical strength of the component, in particular of the fastening means, can be achieved. In order to increase the mechanical strength, it is particularly preferred if the component made of steel is in one piece. “In one piece” can in particular be understood to mean that at least the one-piece part has been created in a forming process and/or is connected.
- the component according to the invention in particular a screw, is preferably a high-strength or ultra-high-strength component, preferably with strengths >800 MPa (so-called high-strength components), particularly preferably over 1200 MPa, more preferably >1400 MPa (so-called ultra-high-strength components), particularly preferably 1200-1900 MPa, in particular 1400 - 1900 MPa.
- Preferred high-strength and ultra-high-strength components are high-strength or ultra-high-strength screws, nuts, chain drives, formed components and/or structural components.
- the component according to the invention in particular the high-strength or ultra-high-strength component, preferably a welded component, an additively manufactured component or a case-hardened component.
- the component or the steel is heat-treated, a so-called tempering, for example by salt bath tempering, in order to set a preferred microstructure.
- the structure of the steel is >70% by volume, more preferably >80% by volume, particularly preferably >90% by volume, bainitic and/or martensitic, in particular after tempering such as heat treatment.
- the proportion of microstructures in percent by volume can be determined, for example, in microscopic images of micrographs, since the surfaces on average over several micrographs images that reflect volumes. For this purpose, the surfaces are determined in several micrographs and the arithmetic mean is formed.
- the microstructure of the steel is >70% by weight, more preferably >80% by weight, particularly preferably >90% by weight bainitic and/or or is martensitic.
- the proportion of austenite (residual austenite) is also preferably ⁇ 20% by volume or weight, in particular ⁇ 10% by volume or weight.
- This structure gives the component according to the invention particularly high strength and toughness. They can be subjected to high and often dynamic axial stress.
- the structure of the component according to the invention is preferably >90% by volume ferritic and/or pearlitic.
- the microstructure of the component according to the invention is preferably >90% by weight ferritic and/or pearlitic prior to tempering.
- the component according to the invention is a formed component.
- a formed component is to be understood in particular as a component which has been formed by means of a forming step, in particular a cold forming process.
- reducing hydrogen embrittlement is advantageous, because formed components already have a certain degree of brittleness due to the accumulated forest dislocations (e.g. two or more dislocations that run across or perpendicular to one another on different slip planes).
- This structural component within the meaning of the invention is present in particular when the component is a load-bearing component.
- This structural component has, in particular, two load introduction sections, which advantageously have load introduction structures, such as mounting recesses or openings, and a transmission area arranged between the load introduction sections, which transmits a load, in particular a bending load and/or tensile load, from one load introduction section to the other load introduction section can and/or transmits.
- the improvement in the resistance to hydrogen embrittlement is attributed to the fact that additional connection points for diffusible hydrogen are created in the microstructure, in particular a heat-treated microstructure of the steel, in particular by precipitation-forming elements such as Al, Cu, Mo, V, Zr, Ti, B with C, N, 0, Si and/or due to the structure set by heat treatment.
- the component according to the invention with a component made of steel is a fastening means in a preferred embodiment.
- the fastening means according to the invention can in particular be non-positive fastening means such as screws, bolts or nuts.
- Force-locking fastening means are characterized in particular by the fact that they have a threaded section for bracing or fastening, in particular with an external thread or an internal thread.
- the threaded section can therefore be an external thread or an internal thread.
- this threaded section is incorporated in a part of the fastener, which is made of steel.
- the fastening means can expediently have a shank area.
- This shank area can be formed adjacent to the threaded section and/or a drive area, in particular a head, of the fastening means.
- the shank region can preferably be designed without a thread and/or be designed as a cylindrical section.
- the diameter of the shank can be larger, smaller or equal to the thread diameter in the threaded section.
- the screws are advantageously high-strength or ultra-high-strength screws.
- the component is a high-strength or ultra-high-strength screw.
- a high-strength bolt is a bolt with a tensile strength of at least 800 MPa.
- High-strength screws are, for example, screws in strength classes 8.8, 10.9 and 12.9.
- the strength classes of the invention correspond to ISO 898-1 in the version valid in January 2021.
- Under an ultra high strength Screw means a screw with a tensile strength, in particular, of at least 1200 MPa and/or advantageously of at least 1400 MPa.
- ultra-high-strength screws are screws in strength classes 12.8, 12.9, 14.8, 14.9, 15.8, 15.9, 16.8, 16.9, 17.8 and 12.8U, 12.9U, 14.8U, 14.9U, 15.8U, 15.9U, 16.8U, 17.8U.
- a high-strength bolt is a bolt that is at least high-strength, but can also be ultra-high-strength. It is preferably a high-strength or ultra-high-strength screw with a strength of more than 1000 MPa.
- the screw can have a head with tool gripping surfaces, these tool gripping surfaces in particular forming an internal or external hexagon with one another.
- the invention also relates to a method for producing the component according to the invention.
- the individual alloying elements are first added to a steel in a known manner.
- the method according to the invention for producing a component with a component made of steel comprises the steps:
- the method according to the invention for producing a component with a component made of steel comprises the steps: a) providing a steel with the composition described above b) rolling, in particular thermomechanical rolling of the steel c) producing a wire or a bar of the steel, d) optional GKZ annealing, e) wire drawing, f) forming and g) optional heat treatment.
- the above steps are performed in the order listed. In each step, the product obtained from the immediately preceding step is further processed.
- the preferred method according to the invention has the advantage of a resource-saving and cost-efficient process route since, for example, a wire rod can be processed directly without GKZ annealing being required in between.
- a ferrite-pearlite structure can be achieved in the wire rod state by means of TM rolling (thermo-mechanical rolling).
- Thermomechanical rolling is preferably carried out in step b).
- Thermomechanical rolling is particularly preferred, in which the material is rolled with a final shape temperature in a range of Ars -50°C and +100°C, Ars being referred to as the austenite-proeutectoid transformation temperature in the Fe-C diagram.
- a structure predominantly made of ferrite and pearlite is particularly preferably produced, in particular with an average secondary grain size of 8 or finer according to ASTM E112.
- GKZ annealing means heating with the aim of nodular cementite formation.
- the optional GKZ annealing it is preferred that the steel is annealed for 6-10 hours, preferably 7-9 hours, for example 8 hours, with a holding temperature of 700-750°C, for example 735°C becomes. It is then preferably cooled to below 100° C., particularly preferably below 50° C., in particular to room temperature.
- a structure of ferrite and nodular cementite is advantageously obtained by annealing (heating).
- step g) is preferably a salt bath tempering, particularly preferably at a temperature of 200-450° C. for 10 minutes to 3 hours.
- the structure of the steel component is predominantly ferritic-pearlitic, bainitic and/or a mixed structure.
- the structure of the steel is preferably >80% by volume, particularly preferably >90% by volume, ferritic-pearlitic, bainitic and/or a mixed structure.
- the microstructure of the component is predominantly martensitic and/or bainitic, as described above.
- the microstructure of the steel component in the component according to the invention is >70% by volume, more preferably >80% by volume, particularly preferably >90% by volume, bainitic or martensitic, as described above.
- the structure of the steel in the edge area in particular the area from the surface of the steel component to a depth of 15 ⁇ m, preferably up to 12 ⁇ m, particularly preferably up to 10 ⁇ m, measured perpendicularly from the surface of the Component made of steel, is predominantly ferritic and/or pearlitic, preferably >80% by volume, particularly preferably >90% by volume, ferritic and/or pearlitic.
- the steel below the depths mentioned above, i.e. below a depth of 15 ⁇ m, preferably below a depth of 12 ⁇ m, particularly preferably below a depth of 10 ⁇ m preferably has the structure described above, i.e. preferably >70% by volume, more preferably >80% by volume, particularly preferably >90% by volume, bainitic or martensitic.
- the steel component has a Vickers hardness of >350 HV in the edge region, in particular at a depth of 30-100 ⁇ m, preferably 50-150 ⁇ m, measured from the surface perpendicular to the surface of the steel component 0.3, more preferably > 400 HV 0.3, particularly preferably > 430 HV 0.3, in particular > 450 HV 0.3.
- the steel component has a Vickers hardness at a depth of 30-100 ⁇ m, preferably 40-120 ⁇ m, particularly preferably 50-150 ⁇ m, measured from the surface perpendicular to the surface of the steel component , which is less than 150 HV 0.3 below the Vickers hardness HV 0.3 of the steel component at a depth of 300-400 pm, in particular at a depth of 400 pm, particularly preferably at a depth of % of the diameter of the steel components.
- the steel component has a Vickers hardness of less than 100 at a depth of 30-100 ⁇ m, preferably 40-120 ⁇ m, particularly preferably 50-150 ⁇ m, measured from the surface perpendicular to the surface of the steel component HV 0.5, more preferably less than 60 HV 0.5, in particular less than 30 HV 0.5, below the Vickers hardness HV 0.5 of the steel component at a depth of 300-400 pm, also measured by the surface to the depth of the steel component, perpendicular to the surface of the steel component, in particular at a depth of 400 ⁇ m, particularly preferably at a depth of the diameter of the steel component.
- the invention also relates to a component with a component made of steel, obtainable by the method according to the invention.
- the component and/or the component made of steel can also have the aforementioned features with regard to the method.
- FIG. 2 shows the course of hardness of the steel in the edge area of a bainitically heat-treated B-alloy screw, with a conventional B-alloy steel being used. It can be seen that there is a clear drop in hardness in the edge area in connection with a greater depth of hardness drop, measured perpendicular to the surface of the screw.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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EP21211997.8A EP4190934A1 (de) | 2021-12-02 | 2021-12-02 | Bauteil aus b-zr-legiertem stahl |
PCT/EP2022/084020 WO2023099654A1 (de) | 2021-12-02 | 2022-12-01 | Bauteil aus b-zr-legiertem stahl |
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EP4247993A1 true EP4247993A1 (de) | 2023-09-27 |
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Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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EP21211997.8A Pending EP4190934A1 (de) | 2021-12-02 | 2021-12-02 | Bauteil aus b-zr-legiertem stahl |
EP22826100.4A Pending EP4247993A1 (de) | 2021-12-02 | 2022-12-01 | Bauteil aus b-zr-legiertem stahl |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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EP21211997.8A Pending EP4190934A1 (de) | 2021-12-02 | 2021-12-02 | Bauteil aus b-zr-legiertem stahl |
Country Status (5)
Country | Link |
---|---|
EP (2) | EP4190934A1 (de) |
KR (1) | KR20240089753A (de) |
CN (1) | CN118339322A (de) |
CA (1) | CA3238223A1 (de) |
WO (1) | WO2023099654A1 (de) |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
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FR2914929B1 (fr) | 2007-04-12 | 2010-10-29 | Mittal Steel Gandrange | Acier a bonne tenue a l'hydrogene pour le formage de pieces mecaniques a tres hautes caracteristiques. |
WO2011040587A1 (ja) * | 2009-10-02 | 2011-04-07 | 株式会社神戸製鋼所 | 機械構造用鋼とその製造方法、及び、肌焼鋼部品とその製造方法 |
EP2546380B1 (de) * | 2010-03-11 | 2016-06-08 | Nippon Steel & Sumitomo Metal Corporation | Hochfester stahldraht und hochfester bolzen mit hervorragender beständigkeit gegen verzögerten bruch sowie herstellungsverfahren dafür |
JP6031022B2 (ja) * | 2013-12-02 | 2016-11-24 | 株式会社神戸製鋼所 | 耐遅れ破壊性に優れたボルト用鋼線および高強度ボルト並びにそれらの製造方法 |
WO2021009543A1 (en) | 2019-07-16 | 2021-01-21 | Arcelormittal | Method for producing a steel part and steel part |
-
2021
- 2021-12-02 EP EP21211997.8A patent/EP4190934A1/de active Pending
-
2022
- 2022-12-01 CN CN202280079461.5A patent/CN118339322A/zh active Pending
- 2022-12-01 CA CA3238223A patent/CA3238223A1/en active Pending
- 2022-12-01 KR KR1020247015995A patent/KR20240089753A/ko unknown
- 2022-12-01 WO PCT/EP2022/084020 patent/WO2023099654A1/de unknown
- 2022-12-01 EP EP22826100.4A patent/EP4247993A1/de active Pending
Also Published As
Publication number | Publication date |
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KR20240089753A (ko) | 2024-06-20 |
CA3238223A1 (en) | 2023-06-08 |
CN118339322A (zh) | 2024-07-12 |
EP4190934A1 (de) | 2023-06-07 |
WO2023099654A1 (de) | 2023-06-08 |
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