WO2023033478A1 - 진공열차 튜브용 열연강판 및 그 제조방법 - Google Patents
진공열차 튜브용 열연강판 및 그 제조방법 Download PDFInfo
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- WO2023033478A1 WO2023033478A1 PCT/KR2022/012878 KR2022012878W WO2023033478A1 WO 2023033478 A1 WO2023033478 A1 WO 2023033478A1 KR 2022012878 W KR2022012878 W KR 2022012878W WO 2023033478 A1 WO2023033478 A1 WO 2023033478A1
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- hot
- steel sheet
- rolled steel
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- vacuum
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- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 114
- 239000010959 steel Substances 0.000 title claims abstract description 114
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 20
- 238000013016 damping Methods 0.000 claims abstract description 26
- 239000011572 manganese Substances 0.000 claims description 53
- 239000010955 niobium Substances 0.000 claims description 32
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 28
- 229910052710 silicon Inorganic materials 0.000 claims description 28
- 239000010703 silicon Substances 0.000 claims description 28
- 238000003466 welding Methods 0.000 claims description 26
- 230000014509 gene expression Effects 0.000 claims description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 22
- 229910052799 carbon Inorganic materials 0.000 claims description 22
- 238000005096 rolling process Methods 0.000 claims description 22
- 229910000859 α-Fe Inorganic materials 0.000 claims description 22
- 238000000034 method Methods 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 19
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 18
- 229910052748 manganese Inorganic materials 0.000 claims description 18
- 239000010936 titanium Substances 0.000 claims description 16
- 238000005098 hot rolling Methods 0.000 claims description 12
- 229910052758 niobium Inorganic materials 0.000 claims description 12
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium atom Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 claims description 12
- 239000012535 impurity Substances 0.000 claims description 11
- 229910001562 pearlite Inorganic materials 0.000 claims description 9
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 8
- 239000002131 composite material Substances 0.000 claims description 8
- 229910052719 titanium Inorganic materials 0.000 claims description 8
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 claims description 8
- 238000004804 winding Methods 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 6
- 230000000704 physical effect Effects 0.000 abstract description 9
- 239000000463 material Substances 0.000 description 42
- 229910045601 alloy Inorganic materials 0.000 description 9
- 239000000956 alloy Substances 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 239000013078 crystal Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000005530 etching Methods 0.000 description 4
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910001563 bainite Inorganic materials 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000004927 fusion Effects 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 230000003287 optical effect Effects 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- 229910000746 Structural steel Inorganic materials 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 239000004917 carbon fiber Substances 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 239000012153 distilled water Substances 0.000 description 2
- 239000004615 ingredient Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- 238000000879 optical micrograph Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- 101100508752 Oryza sativa subsp. japonica IMCE gene Proteins 0.000 description 1
- 239000004113 Sepiolite Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- OXNIZHLAWKMVMX-UHFFFAOYSA-N picric acid Chemical compound OC1=C([N+]([O-])=O)C=C([N+]([O-])=O)C=C1[N+]([O-])=O OXNIZHLAWKMVMX-UHFFFAOYSA-N 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 239000003643 water by type Substances 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C47/00—Winding-up, coiling or winding-off metal wire, metal band or other flexible metal material characterised by features relevant to metal processing only
- B21C47/02—Winding-up or coiling
-
- 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
- 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
- C22C38/12—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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T30/00—Transportation of goods or passengers via railways, e.g. energy recovery or reducing air resistance
Definitions
- the present invention relates to a hot-rolled steel sheet and a method for manufacturing the same, and more particularly, to a hot-rolled steel sheet having excellent properties such as yield strength, vibration damping ratio, weldability, and low-temperature toughness of a welded part suitable for a vacuum train tube, and a method for manufacturing the same.
- a vacuum train also known as a hyper tube train, is a system in which a maglev train moves in a vacuum tube.
- the vacuum train can operate at high speed because there is no friction with air or tracks, which is the main cause of energy loss during train operation. Since it has less energy loss and can save 93% of energy compared to aircraft, it is in the limelight as an eco-friendly next-generation transportation means, and active research is being conducted around the world.
- Patent Document 1 Korean Patent Registration No. 10-2106353 (2020.05.04. Notice)
- a hot-rolled steel sheet having properties suitable for use in vacuum train tubes due to excellent yield strength, vibration damping ratio, weldability, and low-temperature toughness of welded parts, and a method for manufacturing the same.
- carbon (C) 0.03 to 0.11%
- silicon (Si) 1.0 to 2.0%
- manganese (Mn) 1.2 to 2.2%
- the rest It may contain Fe and other unavoidable impurities, have a ferrite and pearlite composite structure as a microstructure, and satisfy the following relational expressions 1 to 3.
- D means the average grain size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
- [C], [Si], and [Mn] are carbon (C) included in the hot-rolled steel sheet, respectively.
- the microstructure of the hot-rolled steel sheet may be composed of 60 to 95 area% of ferrite, 5 to 40 area% of pearlite, and other unavoidable structures.
- the total amount of titanium (Ti), niobium (Nb), and vanadium (V) unavoidably included in the hot-rolled steel sheet may be less than 0.01% (including 0%).
- the average particle size (D) of the ferrite may be 10 to 20 ⁇ m.
- the yield strength of the hot-rolled steel sheet is 350 MPa or more, the Charpy impact energy based on -20 ° C is 27 J or more, and the hot-rolled steel sheet is processed into a specimen having a length * width * thickness of 80 mm * 20 mm * 2 mm, and then bending vibration.
- a vibration damping ratio measured for a frequency of 1650 Hz in a flexural vibration mode may be greater than or equal to 100*10 -6 .
- the Charpy impact energy based on -20 ° C of the weld is 27J or more, and the fraction of the M-A phase included in the weld is 5 area% or less (including 0%) can
- the thickness of the hot-rolled steel sheet may be 10 mm or more.
- [T 1 ], [T 2 ] and [T 3 ] mean slab heating temperature (T 1 , °C), finish rolling temperature (T 2 , °C) and coiling temperature (T 3 , °C), respectively.
- [C] and [Nb] mean the contents (wt%) of carbon (C) and niobium (Nb) contained in the hot-rolled steel sheet, respectively.
- the total amount of titanium (Ti), niobium (Nb), and vanadium (V) unavoidably included in the slab may be less than 0.01% (including 0%).
- a hot-rolled steel sheet having excellent yield strength, vibration damping ratio, weldability, and low-temperature toughness of a welded part suitable for a vacuum train tube and a manufacturing method thereof can be provided.
- FIG. 1 is a photomicrograph of a welded portion formed by welding a base material containing 1.5% by weight of silicon (Si) using a welding material that does not contain silicon (Si).
- FIG. 2 is a photomicrograph of a welded portion formed by welding a base material containing 2.0% by weight of silicon (Si) using a welding material containing 0.3% by weight of silicon (Si).
- the present invention relates to a hot-rolled steel sheet for a vacuum train tube and a method for manufacturing the same.
- preferred embodiments of the present invention will be described. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. These embodiments are provided to those skilled in the art to further elaborate the present invention.
- a vacuum train is a train that runs inside a tube in a vacuum or sub-vacuum state, and is a next-generation transportation method currently in the early stage of development.
- the vacuum train is a means of transportation that can effectively achieve high speed and high efficiency because it eliminates frictional resistance between wheels and tracks and minimizes air resistance.
- the safety of the vacuum train is not sufficiently secured due to the nature of the vacuum train operating at high speed, there is a risk of a major accident.
- a material for a tube for a vacuum train requires more stringent safety.
- the inventors of the present invention have found that the following physical properties are important as a material for a vacuum tube to secure the safety of a vacuum train.
- the first physical property required of materials for vacuum tubes is high strength. Since the vacuum train moves through the inside of the vacuum tube, the material for the vacuum tube is required to have sufficient strength as a structure. In addition, since the inside of the vacuum tube must be maintained in a vacuum or sub-vacuum state, it is required to have sufficient high-strength characteristics so that the shape of the tube is not deformed due to a pressure difference between the inside and outside.
- the second property required of materials for vacuum tubes is vibration damping ability.
- pods with a lifespan or dozens of people on board pass through the inside of the vacuum tube at intervals of several tens of seconds to several minutes.
- vibrations are amplified in the vacuum tube and resonance may occur, and in serious cases, the tube may be damaged. Therefore, when a material having a vibration damping ratio of a certain level or higher is applied to the vacuum tube, vibration in the tube after the preceding pod passes through can be effectively reduced, and the safety of the vacuum train can be effectively contributed.
- the third property required for materials for vacuum tubes is low-temperature toughness.
- the vacuum train can also operate in polar regions or in deep waters. Since the steel material tends to be more easily damaged in a low-temperature or cryogenic environment, when the steel material is applied to a vacuum tube, it is required to have a certain level of low-temperature toughness in order to secure safety. In particular, since the tube for vacuum trains is manufactured in a tube form through welding, it is required to have excellent low-temperature toughness not only in the base material but also in the welded part.
- the inventor of the present invention through in-depth research, recognized that it was possible to achieve both excellent yield strength, vibration damping ratio, weldability and low-temperature toughness of the welded part by strictly controlling the alloy composition content and microstructure of the steel sheet, and derived the present invention. .
- carbon (C) 0.03 to 0.11%
- silicon (Si) 1.0 to 2.0%
- manganese (Mn) 1.2 to 2.2%
- the rest It may contain Fe and other unavoidable impurities, have a ferrite and pearlite composite structure as a microstructure, and satisfy the following relational expressions 1 to 3.
- D means the average grain size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
- [C], [Si], and [Mn] are carbon (C) included in the hot-rolled steel sheet, respectively.
- composition of the steel included in the hot-rolled steel sheet of the present invention will be described in more detail.
- % representing the content of each element is based on weight unless otherwise indicated.
- Carbon (C) is a component that greatly affects the strength of a steel sheet.
- 0.03% or more of carbon (C) may be included in order to secure the strength required for the structure.
- the content of carbon (C) is excessive, the toughness of the material is lowered, the weldability is lowered, and the yield ratio may be increased.
- the present invention may limit the upper limit of the carbon (C) content to 0.11%.
- silicon (Si) oxygenates to form slag in the steelmaking stage, it tends to be removed along with oxygen.
- silicon (Si) is also a component that effectively contributes to improving the strength of the material. Accordingly, the present invention may include 1.0% or more of silicon (Si) for this effect.
- the content of silicon (Si) is excessive, the surface scale may be hindered and the product surface quality may be deteriorated.
- the formation of M-A phase (martensite-austenite complex) in the welded part may be promoted, and the low-temperature toughness of the welded part may be reduced. can be limited to the following.
- Manganese (Mn) is a component that improves strength and hardenability of steel. Therefore, the present invention may include 1.2% or more of manganese (Mn) in order to secure such an effect. On the other hand, if the content of manganese (Mn) is excessive, material deviation may occur due to central segregation, and crack propagation resistance may be inferior. In addition, when the content of manganese (Mn) is excessive, the toughness of the steel may be lowered. In the present invention, the content of manganese (Mn) may be limited to 2.2% or less.
- the hot-rolled steel sheet of the present invention may include remaining Fe and other unavoidable impurities in addition to the above-mentioned components.
- unintended impurities from raw materials or the surrounding environment may inevitably be mixed in the normal manufacturing process, it cannot be entirely excluded. Since these impurities can be known to anyone skilled in the art, all of them are not specifically mentioned in the present specification.
- additional addition of effective ingredients other than the above-mentioned ingredients is not entirely excluded.
- the hot-rolled steel sheet of the present invention actively suppresses the addition of titanium (Ti), niobium (Nb), and vanadium (V), and even if these components are unavoidably included, the total content can be limited to less than 0.01% (including 0%).
- Titanium (Ti), niobium (Nb), and vanadium (V) are typical precipitation strengthening elements, and are components that effectively contribute to improving the strength of steel by generating fine carbonitrides.
- titanium (Ti), niobium (Nb), and vanadium (V) excessively refine the microstructure of the steel and adversely affect the vibration damping ability, the present invention seeks to actively suppress these components.
- titanium (Ti), niobium (Nb), and vanadium (V) are expensive components, and are not preferable from the viewpoint of economic efficiency.
- the present invention does not artificially add these components, and even when they are added inevitably, the total content of these components can be actively suppressed to less than 0.01%.
- a preferred total content of these components may be 0.005% or less, and a more preferred total content of these components may be 0%.
- the hot-rolled steel sheet according to one aspect of the present invention may have a composite structure composed of ferrite and pearlite as a microstructure.
- the present invention can actively suppress the formation of low-temperature structures such as bainite and martensite.
- Low-temperature structures such as bainite and martensite have high strength and low yield ratio, so they can exhibit excellent physical properties as structural materials.
- the thickness of the hot-rolled steel sheet for vacuum train tubes targeted by the present invention is as thick as 10 mm or more, even if a low-temperature structure is introduced, deviation in physical properties occurs in the thickness direction of the steel sheet. This is because the low-temperature structure is formed only on the surface of the steel sheet, and it is difficult to sufficiently form the low-temperature structure to the center of the steel sheet.
- the microstructure of the steel sheet is composed of a composite structure composed of ferrite and pearlite in order to reduce the variation in physical properties, and even if the low-temperature structure such as bainite and martensite is inevitably formed, its fraction is 1 area% or less (0 %) can be actively suppressed.
- the fraction of ferrite may be 60 to 95 area%
- the fraction of pearlite may be 5 to 40% by area.
- the average grain size of ferrite may be limited to a certain range. As the crystal grain size increases, it is advantageous to secure a vibration damping ratio, so the average particle size of ferrite can be limited to 10 ⁇ m or more in the present invention. On the other hand, if the crystal grain size is excessively large, since the strength and low-temperature toughness of the material are inferior, the average grain diameter of ferrite may be limited to 20 ⁇ m or less in the present invention.
- the inventor of the present invention conducted in-depth research on methods for securing the stability of materials for vacuum train tubes, and as a result, the content of carbon (C), silicon (Si) and manganese (Mn) in the low-alloy steel sheet as in the present invention and Recognizing that it is possible to simultaneously secure yield strength, vibration damping ratio, and low-temperature toughness of a welded part when controlling the average grain size of ferrite within a certain range, the following relational expressions 1 to 3 were derived.
- D means the average grain size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
- [C], [Si], and [Mn] are carbon (C) included in the hot-rolled steel sheet, respectively.
- the hot-rolled steel sheet for vacuum train tubes of the present invention satisfies all of the relational expressions 1 to 3, it is possible to simultaneously secure the desired yield resistance, vibration damping ratio, and low-temperature toughness of the welded part.
- the hot-rolled steel sheet for vacuum train tubes of the present invention may have a yield strength of 350 MPa or more and a Charpy impact energy of -20°C or more of 27 J or more. Therefore, the hot-rolled steel sheet for vacuum train tubes of the present invention can secure strength and low-temperature toughness suitable for a structural material, effectively securing structural safety of tubes for vacuum trains.
- the hot-rolled steel sheet for a vacuum train tube according to the present invention may have a vibration damping ratio of 100*10 -6 or more.
- the vibration damping ratio means a vibration damping ratio measured for a frequency of 1650 Hz after striking in a flexural vibration mode for a specimen having a length * width * thickness of 80 * 20 * 2 mm. Since the hot-rolled steel sheet for vacuum train tubes of the present invention has a vibration damping ratio of 100*10 -6 or more, it is possible to effectively suppress vibration amplification in the vacuum tube and effectively prevent damage to the tube for vacuum trains caused by vibration. there is.
- the Charpy impact energy based on -20 ° C of the welded portion may be 27J or more, and the fraction of the M-A phase included in the welded portion is 5 area% or less ( 0% included).
- a preferable weld M-A phase fraction may be 3 area% or less, and a more preferable weld M-A phase fraction may be 1 area% or less.
- the welding portion is a position 1 mm away from the fusion line, and can be interpreted as including both a weld metal portion and a heat-affected zone (HAZ).
- the welding material used for welding in the present invention is not particularly limited, it is preferable to perform welding using a welding material that does not contain silicon (Si). This is because when welding is performed using a welding material containing silicon (Si), there is a possibility that a large amount of hard M-A is formed in the welded portion due to excessive hardenability.
- 1 is a photomicrograph of a welded portion observed by welding a base material containing 1.5% by weight of silicon (Si) using a welding material that does not contain silicon (Si)
- FIG. 2 is a micrograph of 0.3% by weight of silicon (Si ) It is a photomicrograph of a welded portion formed by welding a base material containing 2.0% by weight of silicon (Si) using a welding material containing.
- a large amount of white regions (M-A phase) are observed at the grain boundary, whereas in FIG. 1, it can be seen that the M-A phase is not observed.
- [T 1 ], [T 2 ] and [T 3 ] mean slab heating temperature (T 1 , °C), finish rolling temperature (T 2 , °C) and coiling temperature (T 3 , °C), respectively.
- [C] and [Nb] mean the contents (wt%) of carbon (C) and niobium (Nb) contained in the hot-rolled steel sheet, respectively.
- a steel slab having a predetermined alloy composition is prepared. Since the steel slab of the present invention has an alloy composition corresponding to the above-mentioned hot-rolled steel sheet, the description of the alloy composition of the steel slab is replaced with the description of the alloy composition of the above-described hot-rolled steel sheet.
- the prepared steel slab may be heated at a heating temperature (T 1 ) of 1100 °C to 1300 °C.
- T 1 a heating temperature of 1100 °C to 1300 °C.
- the steel slab can be heated in a temperature range of 1100 ° C or higher.
- a preferred heating temperature of the steel slab may be 1200 ° C. or more.
- a more preferred steel slab heating temperature may be 1250°C or higher.
- the steel slab heating temperature can be limited to 1300 ° C or less.
- a hot-rolled steel sheet may be provided by hot-rolling the heated steel slab at a finish rolling temperature (T 2 ) of 900° C. to 1000° C.
- the steel sheet produced by the hot rolling of the present invention may have a thickness of 10 ⁇ m or more.
- FDT Finishing Delivery Temperature
- the present invention is intended to control the final microstructure to a level of a certain size or higher, hot rolling can be performed at a finish rolling temperature of 900 ° C. or higher.
- a preferred finish rolling temperature may be 950° C. or higher.
- the finish rolling temperature is excessively high, the final microstructure may be excessively coarse, and the upper limit of the finish rolling temperature may be limited to 1000° C.
- the hot-rolled steel sheet provided by hot rolling may be wound at a coiling temperature (T 3 ) of 600° C. to 700° C. after undergoing water cooling. Since the present invention is intended to implement a composite structure of ferrite and pearlite as a final structure, winding can be performed in a temperature range of 600 ° C. or higher. Since the present invention is intended to implement a final microstructure of a certain size or more, it is more preferable to wind it in a temperature range of 650 ° C. or higher. However, if the coiling temperature is excessively high, a coarse microstructure may be formed or the surface quality may be inferior, so the upper limit of the coiling temperature may be limited to 700 ° C.
- the inventor of the present invention conducted in-depth research on technical means for controlling the particle size of the final microstructure, and in order to control the particle size of the final microstructure in the component system of the present invention, the heating temperature (T 1 ) , Finish rolling temperature (T 2 ) during hot rolling and coiling temperature (T 3 ) during coiling of rolled steel sheet should be independently controlled to satisfy a certain range, as well as finish rolling temperature (T 2 ) and coiling temperature ( T 3 ) was confirmed to be controlled within a certain range in connection with each other, and the following relational expression 4 was derived.
- [T 1 ], [T 2 ] and [T 3 ] mean slab heating temperature (T 1 , °C), finish rolling temperature (T 2 , °C) and coiling temperature (T 3 , °C), respectively.
- [C] and [Nb] mean the contents (wt%) of carbon (C) and niobium (Nb) contained in the hot-rolled steel sheet, respectively.
- a slab is heated at a heating temperature (T 1 ) of 1100 ° C to 1300 ° C, and a finish rolling temperature (T 2 ) of 900 ° C to 1000 ° C Hot rolling is performed at 600 ° C. to 700 ° C., and the hot-rolled steel sheet is wound at a coiling temperature (T 3 ) of 600 ° C to 700 ° C. Since it controls, it is possible to effectively implement the microstructure of the target hot-rolled steel sheet.
- the hot-rolled steel sheet manufactured by the above manufacturing method may satisfy the following relational expressions 1 to 3.
- D means the average grain size ( ⁇ m) of ferrite included in the hot-rolled steel sheet
- [C], [Si], and [Mn] are carbon (C) included in the hot-rolled steel sheet, respectively.
- the hot-rolled steel sheet manufactured by the above-described manufacturing method not only has a yield strength of 350 MPa or more and a Charpy impact energy of -20 ° C. of 27 J or more, but also prepares a specimen having a length * width * thickness of 80 * 20 * 2 mm and performs a bending vibration mode ( flexural vibration mode) can satisfy a level of vibration damping ratio of 100*10 -6 or more measured for a frequency of 1650Hz.
- the Charpy impact energy based on -20 ° C of the welded portion may be 27J or more, and the fraction of the M-A phase included in the welded portion is 5 area% or less. (including 0%).
- the welding part may mean a position 1 mm away from the fusion line.
- Psalter No. steel grade process conditions Relation 4 slab heating temperature (T 1 , °C), finish rolling temperature (T 2 , °C) winding temperature (T 3 , °C)
- T 1 , °C slab heating temperature
- T 2 , °C finish rolling temperature
- T 3 winding temperature
- microstructure and mechanical properties of each specimen were analyzed and listed in Table 3, and the satisfaction of relational expressions 1 to 3 of each specimen was also listed in Table 3.
- the microstructure was measured using an optical microscope with a magnification of 500 after etching each specimen with a Nital etching method.
- the grain size of ferrite was measured according to ASTM E112. 3 is an optical microscope image used to observe the microstructure of specimen 1.
- Mechanical properties were measured according to KS B 0802 and KS B 0810, and the measured yield strengths are listed in Table 3 together.
- the vibration damping ratio was measured at room temperature using IMCE's RFDA LTV800. After striking in the flexural vibration mode, the vibration damping ratio in the 1650 Hz region corresponding to the 1 st mode of the vibration modes of the specimen was measured and analyzed, and the results are shown in Table 3 together.
- first etching was performed using a solution of 5 g of EDTA and 0.5 g of NaF in 100 ml of distilled water, followed by 25 g of NaOH and 5 g of picric acid in 100 ml of distilled water. Second etching was performed, and the MA phase fraction was measured according to ASTM E 562.
- the specimens satisfying the alloy composition, process conditions and relational expressions 1 to 4 of the present invention not only satisfy the yield strength of 350 MPa or more, the vibration damping ratio of 100*10 -6 or more, but also -20 While the Charpy impact energy based on °C satisfies 27J or more, it can be seen that specimens that do not satisfy any one or more of the conditions limited by the present invention cannot simultaneously secure the desired physical properties.
- Figure 4 is a microstructure observation picture of EN-S355 taken using an optical microscope.
- a hot-rolled steel sheet having excellent yield strength, vibration damping ratio, and low-temperature toughness of a welded part and having physical properties suitable for a vacuum train tube and a manufacturing method thereof.
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Abstract
Description
강종 | 합금조성(wt%) | |||||
C | Si | Mn | Ti | Nb | V | |
A | 0.07 | 1.6 | 1.7 | - | - | - |
B | 0.07 | 2.1 | 1.5 | - | - | - |
C | 0.07 | 0.8 | 1.7 | - | - | - |
D | 0.07 | 1 | 1.7 | - | 0.045 | - |
E | 0.2 | 1 | 1.2 | - | - | - |
F | 0.07 | 1.6 | 0.8 | - | - | - |
시편 No. |
강종 | 공정조건 | 관계식 4 | ||
슬라브 가열온도 (T1, ℃), |
마무리 압연온도 (T2, ℃) |
권취온도 (T3, ℃) |
|||
1 | A | 1250 | 950 | 700 | 15 |
2 | A | 1250 | 880 | 600 | 5 |
3 | A | 1300 | 1000 | 750 | 22 |
4 | B | 1250 | 950 | 700 | 15 |
5 | C | 1250 | 950 | 700 | 15 |
6 | D | 1250 | 950 | 700 | 7 |
7 | E | 1250 | 950 | 700 | 7 |
8 | F | 1250 | 950 | 700 | 15 |
시편 No. |
강종 | 미세 조직 |
페라이트 평균 입경 (D, ㎛) |
관계식 1 |
관계식 2 |
관계식 3 |
진동 감쇠비 (*10-6) |
항복강도 (MPa) |
용접부 샤르피 에너지 (J, @-20℃) |
용접부 M-A상 분율 (면적%) |
1 | A | F+P | 15 | 412 | 118 | 62 | 110 | 400 | 55 | 1 |
2 | A | F+P | 5 | 486 | 72 | 167 | 56 | 510 | 102 | 1 |
3 | A | F+P | 22 | 394 | 129 | 25 | 110 | 380 | 18 | 1 |
4 | B | F+P | 15 | 445 | 108 | 18 | 113 | 460 | 20 | 11 |
5 | C | F+P | 15 | 337 | 128 | 132 | 130 | 340 | 103 | 0 |
6 | D | F+P | 7 | 403 | 97 | 187 | 88 | 404 | 123 | 0 |
7 | E | F+P | 7 | 426 | 74 | 159 | 65 | 415 | 121 | 0 |
8 | F | F+P | 15 | 350 | 105 | 62 | 101 | 336 | 44 | 1 |
Claims (9)
- 중량%로, 탄소(C): 0.03~0.11%, 실리콘(Si): 1.0~2.0%, 망간(Mn): 1.2~2.2%, 나머지 Fe 및 기타 불가피한 불순물을 포함하고,페라이트 및 펄라이트 복합조직을 미세조직으로 가지며,하기의 관계식 1 내지 관계식 3을 만족하는, 진공열차 튜브용 열연강판.[관계식 1]355 ≤ 11 + 394*D(-0.5) + 448*[C] + 94*[Si] + 69*[Mn][관계식 2]100 ≤ 186 - 240*D(-0.5) - 121*[C] - 13.2*[Si] + 13.7*[Mn][관계식 3]27 ≤ 476 - 95.22*ln(D) - 220*[C] - 88*[Si]상기 관계식 1 내지 관계식 3에서, D는 상기 열연강판에 포함되는 페라이트의 평균 입자 크기(㎛)를 의미하며, [C], [Si] 및 [Mn]은 각각 상기 열연강판에 포함되는 탄소(C), 실리콘(Si) 및 망간(Mn)의 함량(중량%)를 의미한다.
- 제1항에 있어서,상기 열연강판의 미세조직은, 60~95면적%의 페라이트, 5~40면적%의 펄라이트 및 기타 불가피한 조직으로 이루어지는, 진공열차 튜브용 열연강판.
- 제1항에 있어서,상기 열연강판에 불가피하게 포함되는 티타늄(Ti), 니오븀(Nb) 및 바나듐(V)의 합량은 0.01% 미만(0% 포함)인, 진공열차 튜브용 열연강판.
- 제1항에 있어서,상기 페라이트의 평균 입자 크기(D)는 10~20㎛인, 진공열차 튜브용 열연강판.
- 제1항에 있어서,상기 열연강판의 항복강도는 350MPa 이상이고,상기 열연강판의 -20℃ 기준 샤르피 충격 에너지는 27J 이상이며,상기 열연강판을 길이*폭*두께가 80mm*20mm*2mm인 시편으로 가공한 후 굽힘 진동 모드(flexural vibration mode)에서 1650Hz 주파수에 대해 측정한 진동 감쇠비가 100*10 -6 이상인, 진공열차 튜브용 열연강판.
- 제1항에 있어서,서브머지드 아크 용접으로 상기 열연강판을 용접하여 형성된 용접부에서,상기 용접부의 -20℃ 기준 샤르피 충격 에너지는 27J 이상이고,상기 용접부에 포함되는 M-A상의 분율은 5면적% 이하(0% 포함)인, 진공열차 튜브용 열연강판.
- 제1항에 있어서,상기 열연강판의 두께는 10mm 이상인, 진공열차 튜브용 열연강판.
- 중량%로, 탄소(C): 0.03~0.11%, 실리콘(Si): 1.0~2.0%, 망간(Mn): 1.0~2.2%, 나머지 Fe 및 기타 불가피한 불순물을 포함하는 슬라브를 1100℃ 내지 1300℃의 가열 온도(T1)에서 가열하는 단계;상기 가열된 슬라브를 900℃ 내지 1000℃의 마무리 압연온도(T2)로 열간압연하여 열연강판을 제공하는 단계; 및상기 열연강판을 600℃ 내지 700℃의 권취온도(T3)에서 권취하는 단계를 포함하며,상기 마무리 압연온도(T2) 및 권취온도(T3)는 하기의 관계식 4를 만족하는, 진공열차 튜브용 열연강판의 제조방법.[관계식 4]10 ≤ -101.9 + 0.103*[T2] + 0.0339*[T3] -61.9*[C] - 190.2*[Nb] ≤ 20상기 관계식 4에서 [T1], [T2] 및 [T3]는 각각 슬라브 가열온도(T1, ℃), 마무리 압연온도(T2, ℃) 및 권취온도(T3, ℃)를 의미하며, [C] 및 [Nb]는 각각 상기 열연강판에 포함되는 탄소(C) 및 니오븀(Nb)의 함량(중량%)를 의미한다.
- 제8항에 있어서,상기 슬라브에 불가피하게 포함되는 티타늄(Ti), 니오븀(Nb) 및 바나듐(V)의 합량은 0.01% 미만(0% 포함)인, 진공열차 튜브용 열연강판의 제조방법.
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KR102106353B1 (ko) | 2019-07-24 | 2020-05-04 | 태산엔지니어링 주식회사 | 초고강도 레진 모르타르 조성물 및 이를 이용한 수중 구조물 및 하이퍼루프용 튜브의 제작 시공 방법 |
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- 2022-08-29 CN CN202280058914.6A patent/CN117897513A/zh active Pending
- 2022-08-29 KR KR1020247010969A patent/KR20240063927A/ko unknown
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JP2006124773A (ja) * | 2004-10-28 | 2006-05-18 | Sumitomo Metal Ind Ltd | 熱延鋼帯およびその製造方法 |
JP2007291511A (ja) * | 2006-03-29 | 2007-11-08 | Jfe Steel Kk | 靭性に優れた高張力厚鋼板およびその製造方法 |
KR101485237B1 (ko) * | 2010-06-29 | 2015-01-22 | 제이에프이 스틸 가부시키가이샤 | 가공성이 우수한 고강도 강판 및 그 제조 방법 |
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JP2016047956A (ja) * | 2014-08-28 | 2016-04-07 | Jfeスチール株式会社 | 低降伏比高強度スパイラル鋼管杭およびその製造方法 |
KR102106353B1 (ko) | 2019-07-24 | 2020-05-04 | 태산엔지니어링 주식회사 | 초고강도 레진 모르타르 조성물 및 이를 이용한 수중 구조물 및 하이퍼루프용 튜브의 제작 시공 방법 |
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