CN114746568A - Normalized heat-treated steel sheet having good low-temperature impact toughness and method for producing same - Google Patents

Normalized heat-treated steel sheet having good low-temperature impact toughness and method for producing same Download PDF

Info

Publication number
CN114746568A
CN114746568A CN202080083393.0A CN202080083393A CN114746568A CN 114746568 A CN114746568 A CN 114746568A CN 202080083393 A CN202080083393 A CN 202080083393A CN 114746568 A CN114746568 A CN 114746568A
Authority
CN
China
Prior art keywords
steel sheet
less
temperature
impact toughness
treated steel
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
Application number
CN202080083393.0A
Other languages
Chinese (zh)
Inventor
金佑谦
白大雨
尹基镐
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Posco Holdings Inc
Original Assignee
Posco Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Posco Co Ltd filed Critical Posco Co Ltd
Publication of CN114746568A publication Critical patent/CN114746568A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/28—Normalising
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
    • C21D1/60—Aqueous agents
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/001—Heat treatment of ferrous alloys containing Ni
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/005—Heat treatment of ferrous alloys containing Mn
    • 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
    • C21D6/00—Heat treatment of ferrous alloys
    • C21D6/008—Heat treatment of ferrous alloys containing Si
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving a particular fabrication or treatment of ingot or slab
    • 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
    • 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
    • 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
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273—Final recrystallisation annealing
    • 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
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
    • 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
    • C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
    • 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
    • C21D2211/009—Pearlite

Landscapes

  • 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

Provided are a normalized heat-treated steel sheet having excellent low impact toughness and a method for manufacturing the same. The normalized heat-treated steel sheet of the present invention comprises, in weight%: c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003% to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002% to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities, and has a steel microstructure including 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.

Description

Normalized heat-treated steel sheet having excellent low-temperature impact toughness and method for producing same
Technical Field
The present disclosure relates to manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness, and more particularly, to a normalized heat-treated steel sheet having good center impact characteristics of an ultra-thick steel sheet, which may be applied to industrial steels for structural use in various fields such as marine and wind power generation building structures, thereby securing stability and improving the life span of the structure, and a manufacturing method thereof.
Background
In recent years, as energy resources on land or offshore are depleted, resource exploitation areas are gradually shifted to deep sea areas or cold areas, and thus, the resource exploitation areas are becoming increasingly complex due to the enlargement and integration of drilling, exploitation and storage facilities, and the like. The steel used therefore needs to have excellent low-temperature toughness to ensure the stability of the structure, and in particular, needs to minimize a decrease in toughness due to cold working during the process of manufacturing the structure.
The development of ocean energy and resources is expanding to deep sea, cold regions and polar regions, and the construction of floating offshore structures such as SPAR, TLP and FPSO is actively being carried out. With respect to the protection of the marine environment, such offshore structures must be absolutely safe and, therefore, damage to the offshore structures is hardly acceptable.
Furthermore, since the 21 st century, attention has been focused on new renewable energy sources for reducing environmental problems and greenhouse gas emissions. Renewable energy is a term combining new energy (hydrogen, fuel cells, etc.) and renewable energy (solar heat, wind power generation, biology, etc.), and among them, wind power generation is focused as a next-generation energy source as an economically friendly power generation method that does not generate waste and does not generate pollution.
Among wind power generation, onshore wind power generation installed on land has been rapidly increased in recent years mainly in europe due to restrictions on noise, optimal wind power generation space, and the like. Although such offshore wind power generation is started later than onshore wind power generation, the relative advantage of offshore wind power generation over onshore wind power generation is increasingly expressed as the state of the art advances due to various advantages such as strong wind speed, low concern for noise generation, and the ability to secure a large area.
Such offshore wind power generation structures are divided into a mono-pile section buried in the seabed surface, a transition piece section connecting the mono-pile and the tower section, and a tower section supporting the power generation facility.
Wherein the monopile section and the transition piece section support offshore wind power generation. Most of them require cylindrical curved surface processing, and thus thick steel plates that can secure extremely thick and low-temperature toughness are used. In more detail, there is a need for a steel material having a maximum thickness of 120mm and-50 ℃ impact toughness and a yield strength satisfying 350 MPa.
In this regard, steel materials are reinforced and thickened, but it is very important to secure low temperature toughness of ultra-thick materials in terms of safety. However, it is generally attempted to control the grain size by adjusting the heat treatment temperature and performing multi-step heat treatment to improve the impact characteristics in heat-treated steel materials applied to the ocean, wind power generation structures, etc., but basically, a heat-treated steel sheet securing the strength by a high carbon content has a limitation in securing the center portion impact toughness.
[ Prior art documents ]
[ patent document ]
(patent document 1) Korean patent laid-open No. KR2016-0063168
Disclosure of Invention
Technical problem
The present disclosure relates to a steel sheet satisfying a strength of 350MPa or more for a thick steel sheet subjected to normalizing heat treatment and simultaneously having excellent center portion impact toughness. An aspect of the present disclosure is to provide a normalized heat-treated steel sheet having excellent low-temperature impact toughness and a method of manufacturing the same. In the normalized heat-treated steel sheet, by realizing a microstructure including ferrite and spheroidized pearlite having a final grain size of 20 μm or less through heat treatment by controlling a steel composition and a manufacturing method thereof, it is possible to overcome an impact disadvantage of the existing heat-treated steel sheet and to secure strength of a base material and toughness of a central portion at-60 ℃ to-40 ℃, so that the normalized heat-treated steel sheet can be used as a steel material for offshore structures and wind power generation structures.
The subject matter of the present invention is not limited to the above. The subject matter of the present invention will be understood from the entire contents of the present specification, and further subject matters of the present invention will be readily understood by those of ordinary skill in the art to which the present invention pertains.
Technical scheme
In accordance with one aspect of the present disclosure,
a normalized heat-treated steel sheet having good low-temperature impact toughness contains, in weight%: c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003% to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002 to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities, and has a steel microstructure containing 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.
The heat-treated steel sheet has a yield strength of 350MPa or more, and can exhibit an impact absorption energy value at-60 ℃ of 150J or more.
In accordance with another aspect of the present disclosure,
the method for manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness includes the following processes: reheating a steel slab at a temperature of 1020 ℃ to 1150 ℃, the steel slab comprising in weight%: c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003% to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002% to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities;
manufacturing a hot-rolled steel sheet by finish hot-rolling the reheated slab in a non-recrystallization temperature region of Ar3 temperature or higher;
air-cooling or water-cooling the hot rolled steel sheet; and
normalizing, wherein the cooled hot rolled steel sheet is heated to a temperature range of 850 ℃ to 960 ℃, and then maintained for [1.3t + (10 to 30) ] minutes (where t is a value measured in mm of the thickness of the hot rolled steel sheet).
The finish rolling temperature is preferably in the range of 760 ℃ to 810 ℃.
When the hot rolled steel sheet is water-cooled, the steel sheet may be cooled to a temperature range of 500 ℃ to 300 ℃ at a cooling rate of 2 ℃/sec to 30 ℃/sec.
The normalized steel sheet may have a steel microstructure including 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.
Advantageous effects
In the present disclosure having the configuration as described above, it is possible to provide a normalized heat-treated steel having low-temperature toughness characteristics having the following microstructure by controlling the steel composition and manufacturing conditions: the microstructure includes 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite. The super-thick heat-treated steel sheet provided in this manner may have a yield strength of 350MPa or more, and may exhibit a central portion impact absorption energy value of 150J or more excellent at-40 ℃ to-60 ℃.
Further, these steel materials may be applied as structural steel materials for offshore structures and wind power generation structures, and may be prepared for the risk of steel damage due to low water temperature, and may also be applied to shipbuilding and general structural steel requiring low temperature toughness.
Drawings
Fig. 1 is a photograph showing the microstructure of steel before normalizing heat treatment, fig. 1(a) shows a material that has been generally rolled, fig. 1(b) shows a material that has been non-recrystallized zone rolled + air cooled of the present disclosure, and fig. 1(c) shows a material that has been non-recrystallized zone rolled + water cooled.
Fig. 2 shows the final microstructure of the steel after the normalizing heat treatment, fig. 2(a) shows a material that has been subjected to general rolling + normalized, fig. 2(b) shows a material that has been subjected to non-recrystallization zone rolling + air cooling + normalized, and fig. 2(c) shows a material that has been subjected to non-recrystallization zone rolling + water cooling + normalized.
Detailed Description
Hereinafter, the present disclosure will be described.
The present disclosure relates to a heat-treated steel material having excellent impact characteristics of the center portion of an ultra-thick steel sheet, and the heat-treated steel material of the present disclosure may be rolled at a non-recrystallization zone temperature to finely control the initial grain size before normalizing heat treatment. Further, a finer final grain size of 20 μm or less can be formed after the normalizing heat treatment, so that it can be applied to various structural industrial steels such as marine and wind power generation building structures, thereby securing the stability of the structure and improving the life thereof.
In order to achieve the microstructure in the present disclosure, rolling needs to be started at about 870 ℃ to 830 ℃ instead of the conventional high-temperature rolling, and air cooling or water cooling needs to be performed after rolling and heat treatment needs to be performed. The heat-treated super-thick steel plate manufactured in this manner makes it possible to obtain a low-carbon normalized heat-treated steel having improved strength due to a fine final microstructure, so that the heat-treated super-thick steel plate can overcome the disadvantage of the center portion impact toughness, which is a disadvantage of the existing heat-treated steel having a high carbon content, and can have an excellent absorption energy value of 150J or more in the center portion impact toughness even at-60 ℃.
Specifically, the conventional normalized heat-treated steel is a TMCP steel material manufactured by controlling rolling + cooling to secure strength, and has a tendency to be poor in impact toughness even after heat treatment due to its high carbon content. Further, when the heat treatment temperature is excessively high or excessively long, there occurs a case where the strength may be reduced due to grain growth as compared with the steel sheet in a rolled state before the heat treatment.
To overcome this, the present disclosure has the following features: a normalized heat-treated steel material having excellent strength and center-portion impact toughness is provided by performing non-recrystallization zone rolling and water cooling or air cooling after rolling to ensure grain refinement of the structure and achieve final grain refinement after normalization.
The normalized heat-treated steel sheet having good low-temperature impact toughness according to the present disclosure includes, in wt%: c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003% to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002% to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities, and has a steel microstructure including 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.
Hereinafter, the steel constituent components of the present disclosure and the reasons for limiting the contents thereof will be described. Meanwhile, "%" as used herein means "%" by weight unless otherwise specified.
C: 0.04 to 0.1 percent
In the present disclosure, C is an element for ensuring tensile strength by causing solid solution strengthening and existing as carbonitride of Nb or the like. However, if the content of C is less than 0.04%, a decrease in tensile strength may occur due to a decrease in solid solution strengthening by C. On the other hand, when 0.1% or more of C is added, pearlite is generated, which may deteriorate impact and fatigue characteristics at low temperatures, and further, as solid solution C increases, impact characteristics may deteriorate. Therefore, in the present disclosure, it is preferable to limit the C content to a range of 0.04% to 0.1%. More preferably, the C content is limited to 0.06% to 0.09%.
Si: 0.05 to 0.5 percent
Si assists Al in deoxidizing the molten steel and is an essential element for securing yield strength and tensile strength. However, if the content is less than 0.05%, the above effects cannot be obtained and the processing time in the steel making process is greatly increased. On the other hand, when the amount of Si added exceeds 0.5%, diffusion of C is hindered and MA formation is promoted, which may impair impact and fatigue characteristics at low temperatures. Therefore, in the present disclosure, the Si content is preferably limited to a range of 0.05% to 0.5%, and more preferably, the Si content is limited to 0.02% to 0.05% to ensure stable strength.
Mn: 1.0 to 2.0%
Mn is added in an amount of 1.0% or more because Mn has a large strength-improving effect by solid-solution strengthening. However, when Mn is excessively added, deterioration of toughness may occur due to formation of MnS inclusions and segregation in the central portion, and thus the upper limit thereof is limited to 2.0%. More specifically, the Mn content is limited to 1.5% to 2.0% to ensure stable strength.
P: 0.01% or less
Since P is an element that causes grain boundary segregation and may cause steel embrittlement, it is necessary to limit the upper limit of P to 0.01%.
S: 0.003% or less
S mainly combines with Mn to form MnS inclusions, which are factors inhibiting low-temperature toughness. Therefore, in order to ensure low-temperature toughness and low-temperature fatigue characteristics, it is necessary to limit S to a range of 0.003% or less.
Al: 0.015 to 0.04%
In the present disclosure, Al needs to be added in an amount of 0.015% or moreAdded as a main deoxidizer for steel. In addition, at least 0.015% should be added since it is an element necessary to fix the N component during strain aging. However, when the Al addition exceeds 0.04%, it may be due to Al2O3The increase in the fraction and size of inclusions results in deterioration of low-temperature toughness. Further, the Al content is preferably limited to 0.015% to 0.04%, more preferably 0.02% to 0.03%, and since similar to Si, it promotes the production of MA phase of the base material and the welding heat affected zone to reduce low-temperature toughness and low-temperature fatigue characteristics.
Ti: 0.005 to 0.02 percent
Ti combines with N causing strain aging to form Ti nitride (TiN) to reduce the solid solution N content, so Ti must be added by at least 0.005%. These precipitates inhibit coarsening of the microstructure, thereby contributing to refinement of the microstructure and improving toughness. However, if the content of Ti exceeds 0.02%, it may cause fracture by coarsening of precipitates, and solid-solution Ti that cannot be combined with N remains to form Ti carbides (TiC), which lowers the toughness of the base metal and the weld zone, so the upper limit thereof is set to 0.02%. More preferably, the Ti content is limited to 0.01% to 0.015%.
Cu: 0.35% or less
Cu is a component that does not significantly reduce impact toughness and improves the strength of steel through solid solution and precipitation. However, when excessively added, since surface cracking of the steel sheet due to Cu thermal shock may occur, the upper limit thereof is preferably limited to 0.35%, and more preferably, to 0.25% or less.
Ni: 0.05 to 0.8 percent
Ni is an element that can improve both strength and toughness, although the strength is not greatly improved as the Ni content is increased. In order for the effect to occur, Ni must be added by at least 0.05%. However, since it is an expensive element, addition of more than 0.8% is not preferable in terms of economic efficiency. More preferably, the N content is limited to 0.2% to 0.7%.
Nb: 0.003 to 0.03 percent
Nb is an element that suppresses recrystallization during rolling or cooling by solid solution or precipitation of carbonitride to make the structure finer and increase the strength, and the content of Nb needs to be 0.003% or more. However, it is preferable to limit the content of Nb to 0.003% to 0.03% because C aggregation occurs due to C affinity, which promotes the formation of MA phase and reduces toughness and fracture characteristics at low temperatures, and thus. More preferably, the Nb content is limited to 0.01% to 0.025%.
N: 0.002 to 0.008 percent
N is the main element that causes strain aging together with C, and it is desirable to keep N low. Al, Ti, Nb, B, etc. should be appropriately contained to reduce deterioration due to strain aging impact by N. However, if the N content is too high, it becomes difficult to suppress the strain aging effect. Therefore, the N content is limited to 0.008% or less. On the other hand, if the N content is too small, the element added thereto to suppress the deterioration of strain aging impact causes solid solution strengthening or forms other precipitates in a solid solution state to lower the toughness of the base material and the welded portion, so the lower limit of the N content is limited to 0.002%. More preferably, the N content is limited to 0.003% to 0.006%.
Ca: 0.0002 to 0.0050%
When Ca is added to molten steel during steel making after Al deoxidation, Ca combines with S mainly present as MnS and suppresses MnS formation, while forming spherical CaS to suppress cracks in the central portion of the steel. Therefore, in the present disclosure, Ca must be added in an amount of 0.0002% or more in order for the added S to be sufficiently formed into CaS. However, if the addition amount is excessive, the excessive Ca combines with O to produce coarse oxide inclusions, which are elongated and broken in subsequent rolling, serving as crack initiation points at low temperatures. Therefore, the upper limit thereof is limited to 0.0050%.
In the present disclosure, Mo may be contained by 0.05% or less or Cr may be contained by 0.05% or less, as needed.
The remainder of the disclosure may be iron (Fe). However, in a general manufacturing process, inevitable impurities may be inevitably added from raw materials or the surrounding environment, and thus, the impurities may not be excluded. The impurities may be known to those skilled in the general manufacturing process art, and thus, a description of the impurities may not be provided in the present disclosure. The content of other components contained as impurities is acceptable.
Meanwhile, the steel material of the present disclosure mainly includes polygonal ferrite and spheroidized pearlite.
In the steel of the present disclosure, it is necessary to control the ferrite grain size to 20 μm or less to achieve low-temperature impact toughness at-40 to-60 degrees while ensuring the strength of an ultra-thick normalized heat-treated steel sheet having a yield strength of 350MPa or more.
More specifically, the steel material of the present disclosure has a steel microstructure including 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spherical pearlite. If the polygonal ferrite fraction is less than 70 area%, a reduction in toughness and ductility may occur, whereas if the polygonal ferrite fraction exceeds 90 area%, there may be a problem in securing yield strength and tensile strength.
Meanwhile, in general, it is impossible to secure polygonal ferrite having a grain size of 20 μm or less by a general normalizing heat treatment.
Next, a method of manufacturing the normalizing heat-treated steel sheet having excellent low-temperature impact toughness of the present disclosure will be described in detail.
The method for manufacturing a normalized heat-treated steel sheet of the present disclosure includes the following processes: reheating a steel billet having the above composition at a temperature of 1020 ℃ to 1150 ℃; manufacturing a hot-rolled steel sheet by finish hot-rolling the reheated steel slab in a non-recrystallization temperature region of Ar3 temperature or higher; air-cooling or water-cooling the hot rolled steel sheet to a temperature range of 500 ℃ to 300 ℃; and normalizing, wherein the cooled hot rolled steel sheet is heated to a temperature range of 850 ℃ to 960 ℃, and then maintained for [1.3t + (10 to 30) ] minutes (where t is a value measured in mm of the thickness of the hot rolled steel sheet).
That is, the manufacturing process of the steel of the present disclosure includes slab reheating; rolling the slab in the non-recrystallized region; the process of cooling, and the contents of each process are as follows.
First, in the present disclosure, a steel slab having the above composition is reheated to 1020 ℃ to 1150 ℃.
The reheating temperature is preferably from 1020 ℃ to 1150 ℃. If the heating temperature is too high (more than 1150 ℃), the crystal grains of austenite become coarse, so that the toughness may be lowered. If the heating temperature is too low (less than 1050 ℃), there may be a case where Ti, Nb, or the like may not be sufficiently dissolved, which may result in a decrease in strength.
Next, in the present disclosure, a hot rolled steel sheet is manufactured by finish hot rolling the reheated slab in a non-recrystallization temperature region of Ar3 or higher.
In the present disclosure, the recrystallization zone rolling during hot rolling only plays a role in adjusting the size of the product width. That is, in the present disclosure, grain refinement may be achieved by minimizing recrystallization rolling and maximizing non-recrystallization rolling. If the slab width is greater than the slab width after rolling, it is preferable to omit recrystallization zone rolling.
In the present disclosure, the non-recrystallized zone rolling should be started at a recrystallization temperature of about 850 ℃ or less and should be completed at an Ar3 temperature of about 750 ℃ or more and have a rolling amount of 90% to 100% with respect to the target thickness.
If the finish rolling temperature is higher than the non-recrystallization temperature, grain size growth occurs before air cooling or water cooling, which makes it difficult to ensure strength and toughness. If the finish rolling temperature is lower than the Ar3 temperature, two-phase zone rolling occurs and the structure becomes anisotropic and banded, which may result in a significant decrease in impact toughness.
In the present disclosure, the finish rolling temperature is preferably in the range of 760 ℃ to 810 ℃.
In the present disclosure, the hot rolled steel sheet is air-cooled or water-cooled.
In the present disclosure, the finish hot rolled steel sheet achieves strength and microstructure by water cooling or air cooling. In the case of water cooling, although there is a difference depending on the thickness, the cooling is preferably performed to 500 ℃ to 300 ℃ at a cooling rate of 2 ℃/sec to 30 ℃/sec.
In the steel material produced in this way, the microstructure of the water-cooled material comprises: ferrite having a size of 20 μm or less, an average of about 13 μm, and a fraction of 80 area% or more; and 20 area% or less of MA and cementite.
Meanwhile, the microstructure of the steel material manufactured by air cooling includes: ferrite having a size of 20 μm or less, an average of about 16 μm, and a fraction of 75 to 90 area%; and pearlite having about 10 to 25 area%.
Subsequently, in the present disclosure, a normalizing heat treatment is performed, in which the cooled hot rolled steel sheet is heated to a temperature range of 850 ℃ to 960 ℃, and then maintained for [1.3t + (10 to 30) ] minutes [ where t is a value measured in mm of the thickness of the hot rolled steel sheet ].
When the normalizing temperature is lower than 850 ℃ or the holding time is less than (1.3t +10) minutes, it is difficult to re-dissolve cementite in pearlite, and thus dissolved C is reduced, thereby making it difficult to secure strength, and finally, residual cementite remains roughly. On the other hand, when the normalizing temperature exceeds 960 ℃ or the holding time exceeds (1.3t +30) minutes, all carbides existing in ferrite grains move to grain boundaries or coarsen the carbides, so that a spheroidal pearlite distribution cannot be formed. As the cooling time during air cooling after heat treatment increases, the ferrite grain size increases, which may result in a decrease in strength and toughness.
The super-thick normalized heat-treated steel of the present disclosure prepared in this manner may exhibit excellent impact toughness, including 70 to 90 area% of ferrite having an average particle diameter of 20 μm or less and 10 to 30 area% of spheroidized pearlite in a final microstructure.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
Hereinafter, the present disclosure will be described in more detail by examples.
(examples)
After preparing molten steels having the composition shown in the following table 1, steel billets were manufactured using continuous casting. The thus manufactured steel slabs were subjected to hot rolling, cooling, and normalizing treatment under the manufacturing conditions shown in table 2 below to manufacture steel plates. Meanwhile, in table 1 below, inventive steels a to C were steel sheets satisfying the composition ranges specified in the present disclosure, and comparative steels D to E were steel sheets not satisfying the composition ranges specified in the present disclosure, and in table 1, the unit of each element content was wt%.
Mechanical properties of each of the prepared steel sheets were measured and are shown in table 3 below. Here, each tissue fraction and grain size were obtained by image analysis using optical microscopy. Further, by obtaining a round specimen from 1/4 thickness of the steel sheet in the direction perpendicular to rolling by working in accordance with ASTM tensile standards, tensile strength, yield strength and elongation by tensile tests, and by working the specimen and then performing impact tests at various temperatures (-40 ℃ C., -60 ℃ C.), an impact value of 1/4 thickness of the steel sheet in the direction perpendicular to rolling was also obtained.
[ Table 1]
Figure BDA0003673159790000121
[ Table 2]
Figure BDA0003673159790000131
[ Table 3]
Figure BDA0003673159790000141
As shown in tables 1 to 3, it can be seen that inventive examples 1 to 3 satisfying all alloy compositions and manufacturing conditions set forth in the present disclosure can secure a yield strength of 350MPa or more and an impact toughness at-40 ℃, -60 ℃ of 150J or more, which are excellent.
In contrast, comparative examples 1 to 3 are cases in which the alloy compositions proposed in the present disclosure are satisfied but the manufacturing conditions are not satisfied, and it can be seen that at least one mechanical property disadvantage occurs. Specifically, comparative examples 1 and 2 show a technique using general rolling, comparative example 1 being a case where rolling at a high temperature is performed and cooling, and comparative example 2 being a case where rolling at a high temperature is performed and then air-cooling, and it can be seen that strength and toughness are poor because grain growth occurs in both. Comparative example 3 is a case in which the normalizing heat treatment is performed for a long time, and shows that the strength and toughness are reduced due to the ferrite growth.
Further, it can be seen that comparative example 4 is a case where the C content exceeds the alloy composition proposed in the present disclosure so that the impact toughness is poor, and comparative example 5 is a case where the C content is insufficient so that the yield strength is not satisfied.
Meanwhile, fig. 1 shows a photograph showing a microstructure of a steel before normalizing heat treatment, fig. 1(a) shows a steel material of comparative example 2 subjected to general rolling, fig. 1(b) is a steel material of inventive example 3 subjected to non-recrystallization zone rolling + air cooling of the present disclosure, and fig. 1(c) shows a steel material of inventive example 2 in which non-recrystallization zone rolling + water cooling of the present disclosure is performed.
Fig. 2 is a photograph showing the final microstructure of the steel after the normalizing heat treatment, fig. 2(a) shows a steel material of comparative example 2 subjected to general rolling + normalizing, fig. 2(b) is a steel material of inventive example 3 subjected to non-recrystallization zone rolling + air cooling + normalizing of the present disclosure, and fig. 2(c) shows a steel material of inventive example 2 in which non-recrystallization zone rolling + water cooling + normalizing of the present disclosure is performed.
The present invention is not limited to the above-described embodiments and examples, but may be embodied in various different forms, and those skilled in the art to which the present invention pertains will appreciate that the present invention may be embodied in other ways without changing the concept or essential features of the invention. It should be understood that it may be embodied in specific forms. It is therefore to be understood that the above described embodiments and examples are illustrative in all respects and not restrictive.

Claims (6)

1. A normalized heat-treated steel sheet having good low-temperature impact toughness, comprising in weight%:
c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003 to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002% to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities, and has a steel microstructure including 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.
2. The normalized heat-treated steel sheet having good low-temperature impact toughness according to claim 1, wherein the heat-treated steel sheet has a yield strength of 350MPa or more and an impact absorption energy value at-60 ℃ of 150J or more.
3. A method for manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness, comprising the steps of:
reheating a steel slab at a temperature of 1020 ℃ to 1150 ℃, the steel slab comprising in weight%: c: 0.04% to 0.1%, Si: 0.05 to 0.5%, Mn: 1.0% to 2.0%, soluble Al: 0.015 to 0.04%, Nb: 0.003% to 0.03%, Ti: 0.005% to 0.02%, Cu: 0.35% or less, Ni: 0.05% to 0.8%, N: 0.002 to 0.008%, P: 0.01% or less but not including 0%, S: 0.003% or less, and the balance of Fe and inevitable impurities;
manufacturing a hot-rolled steel sheet by finish hot-rolling the reheated slab in a non-recrystallization temperature region of Ar3 temperature or higher;
air-cooling or water-cooling the hot rolled steel sheet; and
normalizing, wherein the cooled hot rolled steel sheet is heated to a temperature range of 850 ℃ to 960 ℃, and then maintained for [1.3t + (10 to 30) ] minutes, wherein t is a value measured in mm of the thickness of the hot rolled steel sheet.
4. The method for manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness according to claim 3, wherein the finish rolling temperature is in the range of 760 ℃ to 810 ℃.
5. The method for manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness according to claim 3, wherein the hot-rolled steel sheet is cooled to a temperature range of 500 ℃ to 300 ℃ at a cooling rate of 2 ℃/sec to 30 ℃/sec while the hot-rolled steel sheet is water-cooled.
6. The method for manufacturing a normalized heat-treated steel sheet having good low-temperature impact toughness according to claim 3, wherein the normalized steel sheet has a steel microstructure containing 70 to 90 area% of polygonal ferrite having a grain size of 20 μm or less and 10 to 30 area% of spheroidized pearlite.
CN202080083393.0A 2019-12-06 2020-11-27 Normalized heat-treated steel sheet having good low-temperature impact toughness and method for producing same Pending CN114746568A (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
KR10-2019-0162011 2019-12-06
KR1020190162011A KR102255822B1 (en) 2019-12-06 2019-12-06 Normalling heat treatable steel sheet having godd low impact toughness and method for the same
PCT/KR2020/017125 WO2021112503A1 (en) 2019-12-06 2020-11-27 Normalizing heat treated steel sheet having good low impact toughness and method for manufacturing same

Publications (1)

Publication Number Publication Date
CN114746568A true CN114746568A (en) 2022-07-12

Family

ID=76145196

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202080083393.0A Pending CN114746568A (en) 2019-12-06 2020-11-27 Normalized heat-treated steel sheet having good low-temperature impact toughness and method for producing same

Country Status (5)

Country Link
US (1) US20220403479A1 (en)
EP (1) EP4071261A4 (en)
KR (1) KR102255822B1 (en)
CN (1) CN114746568A (en)
WO (1) WO2021112503A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114807766A (en) * 2022-05-05 2022-07-29 重庆钢铁股份有限公司 Microalloy steel plate for low-temperature pressure vessel and production method thereof
KR20240098514A (en) * 2022-12-21 2024-06-28 주식회사 포스코 Steel sheet having excellent strength and toughness, and method for manufacturing the same

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110060449A (en) * 2009-11-30 2011-06-08 주식회사 포스코 Pressure vessel steel plate with excellent low temperature toughness and hydrogen induced cracking resistance and manufacturing method thereof
CN102304670A (en) * 2011-09-22 2012-01-04 首钢总公司 Steel plate with -40 DEG C strain aging and high toughness and production method thereof
CN102605283A (en) * 2012-04-18 2012-07-25 江苏省沙钢钢铁研究院有限公司 Low-cost high-toughness low-temperature pressure vessel steel and manufacturing method thereof
WO2019074236A1 (en) * 2017-10-11 2019-04-18 주식회사 포스코 Thick steel plate having excellent low-temperature strain aging impact property and manufacturing method therefor
CN110088334A (en) * 2016-12-22 2019-08-02 株式会社Posco Thick steel plate and its manufacturing method with excellent low-temperature impact toughness

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07278656A (en) * 1994-04-04 1995-10-24 Nippon Steel Corp Production of low yield ratio high tensile strength steel
KR100928782B1 (en) * 2007-12-26 2009-11-25 주식회사 포스코 High-strength structural steel with excellent low temperature toughness and tensile strength at welded heat affected zone and its manufacturing method
JP5369462B2 (en) * 2008-03-21 2013-12-18 Ｊｆｅスチール株式会社 Low yield ratio high strength steel sheet and method for producing the same
RU2518830C1 (en) * 2010-06-30 2014-06-10 Ниппон Стил Энд Сумитомо Метал Корпорейшн Hot-rolled steel sheet and method of its production
KR101253890B1 (en) * 2010-12-28 2013-04-16 주식회사 포스코 Ultra thick steel sheet for pressure vessel having excellent central properties and hydrogen induced cracking resistance, and method for manufacturing the same
JP5981813B2 (en) * 2012-09-11 2016-08-31 株式会社神戸製鋼所 High strength steel sheet with excellent low temperature toughness and method for producing the same
KR20160063168A (en) 2014-11-26 2016-06-03 현대제철 주식회사 Steel and method of manufacturing the same
KR20160075925A (en) * 2014-12-19 2016-06-30 주식회사 포스코 Pressure vessel steel plate with excellent hydrogen induced cracking resistance and low temperature toughness and manufacturing method thereof
EP3239332B1 (en) * 2014-12-24 2019-11-20 Posco High-strength steel having superior brittle crack arrestability, and production method therefor
CN106086650B (en) * 2016-07-25 2018-05-01 江阴兴澄特种钢铁有限公司 It is a kind of can Large Heat Input Welding polar region ship plate and preparation method thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20110060449A (en) * 2009-11-30 2011-06-08 주식회사 포스코 Pressure vessel steel plate with excellent low temperature toughness and hydrogen induced cracking resistance and manufacturing method thereof
CN102304670A (en) * 2011-09-22 2012-01-04 首钢总公司 Steel plate with -40 DEG C strain aging and high toughness and production method thereof
CN102605283A (en) * 2012-04-18 2012-07-25 江苏省沙钢钢铁研究院有限公司 Low-cost high-toughness low-temperature pressure vessel steel and manufacturing method thereof
CN110088334A (en) * 2016-12-22 2019-08-02 株式会社Posco Thick steel plate and its manufacturing method with excellent low-temperature impact toughness
WO2019074236A1 (en) * 2017-10-11 2019-04-18 주식회사 포스코 Thick steel plate having excellent low-temperature strain aging impact property and manufacturing method therefor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
轧制技术及连轧自动化国家重点实验室（东北大学）: "《超细晶钢——钢的组织细化理论与控制技术》", 中国矿业大学出版社, pages: 140 - 576 *

Also Published As

Publication number Publication date
EP4071261A1 (en) 2022-10-12
EP4071261A4 (en) 2024-06-19
KR102255822B1 (en) 2021-05-25
US20220403479A1 (en) 2022-12-22
WO2021112503A1 (en) 2021-06-10

Similar Documents

Publication Publication Date Title
JP6198937B2 (en) HT550 steel sheet with ultra-high toughness and excellent weldability and method for producing the same
US10093999B2 (en) Steel plate resistant to zinc-induced crack and manufacturing method therefor
JP2005320624A (en) Thick high-strength steel plate having excellent low-temperature toughness in weld heat-affected zone effected by large heat input welding
CN111511950A (en) Thick steel plate having excellent low-temperature toughness and method for producing same
KR101778406B1 (en) Thick Plate for Linepipes Having High Strength and Excellent Excessive Low Temperature Toughness And Method For Manufacturing The Same
CN104073731B (en) Method for producing ultrahigh-strength ship plate by adopting direct quenching process
CN111155022B (en) 390 MPa-grade polar region hull structural steel with low-temperature toughness and preparation method thereof
US20220403479A1 (en) Normalizing heat-treated steel sheet having good low-temperature impact toughness and method for manufacturing same
CN111225987B (en) Thick steel sheet having excellent low-temperature strain aging impact characteristics and method for producing same
KR101465088B1 (en) Low carbon high strength steel plates with good low temperature toughness and manufacturing method for the same
CN113832413B (en) Ultra-thick 800 MPa-grade quenched and tempered steel plate with excellent core low-temperature impact toughness and weldability and manufacturing method thereof
JP2008069380A (en) High-strength thick steel plate excellent in brittle crack propagation preventing property and its manufacturing method
KR101359082B1 (en) Thick steel sheet with excellent low temperature dwtt property and method for producing same
CN113832387A (en) Low-cost ultra-thick 1000 MPa-grade steel plate and manufacturing method thereof
JP4133175B2 (en) Non-water cooled thin low yield ratio high strength steel with excellent toughness and method for producing the same
CN108265226A (en) The offshore wind farm steel and manufacturing method of yield strength >=460MPa
CN112899558B (en) 550 MPa-grade weather-resistant steel plate with excellent weldability and manufacturing method thereof
KR20130076578A (en) Thick steel plate for offshore structure having ultra-high strength and method for manufacturing the steel plate
KR20230094381A (en) Steel plate having high strength and excellent impact toughness after deformation and method for manufacturing the same
CN111566248B (en) Hot-rolled steel sheet and steel pipe having excellent low-temperature toughness, and method for producing same
CN118302559A (en) Steel sheet having high strength and excellent low-temperature impact toughness, and method for manufacturing same
KR20240106709A (en) Thick steel plate and method of manufacturing the same
CN116891976A (en) 400 Mpa-grade low Wen Haigong steel plate with good wear resistance and preparation method thereof
CN115537647A (en) High-toughness, low-yield-ratio and low-longitudinal-transverse-strength anisotropic 600 MPa-grade steel plate and manufacturing method thereof
CN117836460A (en) Steel material having high strength and excellent impact toughness and method for producing the same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination