EP4343014A1 - Austenitic stainless steel and manufacturing method thereof - Google Patents

Austenitic stainless steel and manufacturing method thereof Download PDF

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EP4343014A1
EP4343014A1 EP22837831.1A EP22837831A EP4343014A1 EP 4343014 A1 EP4343014 A1 EP 4343014A1 EP 22837831 A EP22837831 A EP 22837831A EP 4343014 A1 EP4343014 A1 EP 4343014A1
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comparative example
stainless steel
austenitic stainless
less
cold
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German (de)
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French (fr)
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Minam PARK
Sangseok KIM
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Posco Holdings Inc
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Posco Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • 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
    • C21D6/004—Heat treatment of ferrous alloys containing Cr and 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
    • 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
    • C21D8/0221—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
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236—Cold rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—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
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—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
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
    • 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
    • C21D2211/001—Austenite

Definitions

  • the present disclosure relates to an austenitic stainless steel with a high yield strength and a method for manufacturing the same, and more particularly, to a ultrafine austenitic stainless steel simultaneously satisfying a high strength, a high elongation, and a high yield ratio and a method for manufacturing the same.
  • austenitic stainless steels have been applied for various uses to manufacture components for transportation and construction due to excellent formability, work hardenability, and weldability.
  • 304 series stainless steels or 301 series stainless steels have low yield strengths of 200 to 350 MPa, and there are limits to apply these stainless steels to structural materials.
  • a skin pass rolling process is generally conducted to increase yield strength of 300 series stainless steels for common use.
  • the skin pass rolling process may cause problems in increasing manufacturing costs and significantly deteriorating elongation of materials.
  • Patent Document 0001 discloses a method for manufacturing a 300 series stainless steel having a small curvature even after half etching by performing stress relief (SR) heat treatment twice after skin pass rolling a cold-annealed steel material.
  • SR stress relief
  • the method disclosed in Patent Document 0001 is a method used to control etchability and curvature after etching.
  • ASP austenitic stability parameter
  • Patent Document 2 discloses a method of performing heat treatment for a long time over 48 hours in a temperature range of 600 to 700°C to adjust an average grain size to 10 ⁇ m or less. According to Patent Document 2, productivity decreases in the case of being implemented in a real production line, and manufacturing costs increase.
  • a ultrafine austenitic stainless steel simultaneously satisfying a high strength, a high elongation, and a high yield ratio and a method for manufacturing the same.
  • an austenitic stainless steel includes, in percent by weight (wt%), 0.005 to 0.03% of carbon (C), 0.1 to 1.0% of silicon (Si), 0.1 to 2.0% of manganese (Mn), 6.0 to 12.0% of nickel (Ni), 16.0 to 20.0% of chromium (Cr), 0.01 to 0.2% of nitrogen (N), 0.25% or less of niobium (Nb), and the balance of iron (Fe) and inevitable impurities, wherein a thickness central region has an average grain size d of 5 ⁇ m or less, and a fraction of a unrecrystallized area in a band form is 10% or less.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have a yield strength of at least 700 MPa but not more than 1113 MPa.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have an elongation of at least 20% but not more than 41.2%.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have a yield ratio of at least 0.8 but not more than 0.96.
  • a method for manufacturing an austenitic stainless steel includes: hot rolling a slab including 0.005 to 0.03% of C, 0.1 to 1.0% of Si, 0.1 to 2.0% of Mn, 6.0 to 12.0% of Ni, 16.0 to 20.0% of Cr, 0.01 to 0.2% of N, 0.002 to 0.25% of Nb, and the balance of Fe and inevitable impurities, wherein a thickness central region has an average grain size d of 5 ⁇ m or less, and a fraction of a unrecrystallized area in a band form is 10% or less, cold rolling the hot-rolled slab at room temperature with a reduction ratio of 40% or more, and cold annealing the resultant to satisfy a S2 value of 0.8 or more represented by Equation (1) below.
  • Equation (1) [C], [Si], [Mn], [Cr], [Ni], [N], and [Nb] represent weight percentages (wt%) of respective elements
  • Md30 is a value defined by 551-462([C]+[N])-9.2*[Si]-8.1*[Mn]-13.7*[Cr]-29([Ni]+[Cu])-18.5*[Mo]-68([Nb]+[V])
  • Temp is a cold annealing temperature (°C).
  • the cold rolling may be performed after the hot rolling without performing hot annealing.
  • a ultrafine austenitic stainless steel simultaneously satisfying a high strength, a high elongation, and a high yield ratio, and a method for manufacturing the same.
  • An austenitic stainless steel includes, in percent by weight (wt%), 0.005 to 0.03% of carbon (C), 0.1 to 1.0% of silicon (Si), 0.1 to 2.0% of manganese (Mn), 6.0 to 12.0% of nickel (Ni), 16.0 to 20.0% of chromium (Cr), 0.01 to 0.2% of nitrogen (N), 0.25% or less of niobium (Nb), and the balance of iron (Fe) and inevitable impurities, wherein a thickness central region has an average grain size d of 5 ⁇ m or less, and a fraction of a unrecrystallized area in a band form is 10% or less.
  • An austenitic stainless steel includes, in percent by weight (wt%), 0.005 to 0.03% of carbon (C), 0.1 to 1.0% of silicon (Si), 0.1 to 2.0% of manganese (Mn), 6.0 to 12.0% of nickel (Ni), 16.0 to 20.0% of chromium (Cr), 0.01 to 0.2% of nitrogen (N), 0.25% or less of niobium (Nb), and the balance of iron (Fe) and inevitable impurities.
  • the content of carbon (C) may be from 0.005 to 0.03%.
  • C is an austenite phase-stabilizing element.
  • C may be added in an amount of 0.005% or more.
  • an excess of C may cause a problem of forming a chromium carbide during low-temperature annealing to deteriorate grain boundary corrosion resistance.
  • an upper limit of the C content may be set to 0.03 wt%.
  • the content of silicon (Si) may be from 0.1 to 1.0%.
  • Si is an element added as a deoxidizer during a steel-making process and has an effect on improving corrosion resistance of a steel by forming an Si oxide in a passivated layer in the case of performing a bright annealing process.
  • Si may be added in an amount of 0.1 wt% or more in the present disclosure.
  • an excess of Si may cause a problem of deteriorating ductility.
  • an upper limit of the Si content may be set to 1.0 wt% or less.
  • the content of manganese (Mn) may be from 0.1 to 2.0%.
  • Mn is an austenite phase-stabilizing element.
  • Mn may be added in an amount of 0.1% or more.
  • an excess of Mn may cause a problem of deteriorating corrosion resistance.
  • an upper limit of the Mn content may be set to 2.0%.
  • the content of nickel (Ni) may be from 6.0 to 12.0%.
  • Ni is an austenite phase-stabilizing element and has an effect on softening a steel material.
  • Ni may be added in an amount of 6.0% or more.
  • an excess of Ni may cause a problem of increasing manufacturing costs.
  • an upper limit of Ni may be set to 12.0%.
  • the content of chromium (Cr) may be from 16.0 to 20.0%.
  • Cr is a major element for improving corrosion resistance of a stainless steel.
  • Cr may be added in an amount of 16.0 wt% or more.
  • an excess of Cr may cause problems of hardening a steel material and inhibiting strain-induced martensite transformation during cold rolling.
  • an upper limit of the Cr content may be set to 20.0%.
  • the content of nitrogen (N) may be from 0.01 to 0.2%.
  • N is an austenite phase-stabilizing element and enhances strength of a steel material.
  • N may be added in an amount of 0.01% or more.
  • an excess of N may cause problems such as hardening of a steel material and deteriorating hot workability.
  • an upper limit of the N content may be set to 0.2%.
  • the content of niobium (Nb) may be from 0.25% or less. Addition of Nb that induces formation of Nb-based Z-phase precipitates has an effect on inhibiting the growth of crystal grains. However, an excess of Nb may cause a problem of increasing manufacturing costs. In consideration thereof, an upper limit of the Nb content may be set to 0.25%.
  • the remaining component of the composition of the present disclosure is iron (Fe).
  • the composition may include unintended impurities inevitably incorporated from raw materials or surrounding environments, and thus addition of other alloy components is not excluded.
  • the impurities are not specifically mentioned in the present disclosure, as they are known to any person skilled in the art of manufacturing.
  • a thickness central region may have an average grain size d of 5 ⁇ m or less, and a fraction of a unrecrystallized area in a band form may be 10% or less.
  • TRIP transformation to transform an austenite phase to a martensite phase is used.
  • an average grain size d of the thickness central region is controlled to 5 ⁇ m or less by TRIP transformation. Meanwhile, when the average grain size d of the thickness central region exceeds 5 ⁇ m, a yield strength decreases by Hall-Petch equation.
  • a portion remaining without being transformed into the martensite phase during cold rolling is shown as a unrecrystallized area.
  • a problem of decreasing ductility may be cause. Therefore, it is preferable to adjust the fraction of the unrecrystallized area to 10% or less.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have a yield strength of at least 700 MPa not more than 1113 MPa.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have an elongation of at least 20% but not more than 41.2%.
  • the austenitic stainless steel according to an embodiment of the present disclosure may have a yield ratio of at least 0.8 but not more than 0.96.
  • the yield ratio refers to a value obtained by dividing a yield strength by a tensile strength.
  • a method for manufacturing an austenitic stainless steel includes hot rolling a slab including, in percent by weight (wt%), 0.005 to 0.03% of C, 0.1 to 1.0% of Si, 0.1 to 2.0% of Mn, 6.0 to 12.0% of Ni, 16.0 to 20.0% of Cr, 0.01 to 0.2% of N, 0.002 to 0.25% of Nb, and the balance of Fe and inevitable impurities, wherein a thickness central region has an average grain size d of 5 ⁇ m or less, and a fraction of a unrecrystallized area in a band form is 10% or less, cold rolling the hot-rolled slab at room temperature with a reduction ratio of 40% or more, and cold annealing a resultant to satisfy a S2 value of 0.8 or more represented by Equation (1) below.
  • Equation (1) [C], [Si], [Mn], [Cr], [Ni], [N], and [Nb] represent weight percentages (wt%) of respective elements
  • Md30 is a value defined by 551-462([C]+[N])-9.2*[Si]-8.1*[Mn]-13.7*[Cr]-29([Ni]+[Cu])-18.5*[Mo]-68([Nb]+[V])
  • Temp is a cold annealing temperature (°C).
  • the slab may be prepared as a hot-rolled steel material by a hot rolling process. Subsequently, the hot-rolled steel material may be cold-rolled at room temperature to prepare a cold-rolled steel material.
  • the prepared cold-rolled steel material may be cold-annealed.
  • the cold annealing may be performed in a temperature range of 700 to 850°C to satisfy the ⁇ value represented by Equation (1) above to be 0.8 or more.
  • the steel material may be cold-rolled after the hot rolling without performing an annealing process.
  • productivity increases and manufacturing costs may be reduced.
  • the slabs including the elements listed in Table 1 below were hot-rolled and cold-rolled with a total thickness reduction ratio of 40% or more after performing an annealing process at a temperature of 1000 to 1150°C or without performing the annealing process. Then, annealing was performed in temperature ranges shown in Table 1 below to prepare cold-annealed materials.
  • Example 1 Table 1 Category Composition of alloying elements (wt%) Temp (°C) C Si Mn Cr Ni Cu Mo N Nb V
  • Example 2 0.02 0.51 0.98 17.3 6.3 0 0 0.1 0 0 750
  • Example 3 0.019 0.3 0.46 17.3 6.3 0.25 0.1 0.15 0.21 0 750
  • Example 4 0.018 0.3 0.3 18.1 7.96 0.24 0.1 0.021 0.1 0 750
  • Example 5 0.021 0.41 1 17.3 7.19 0.24 0.1 0.15 0 0.2 750
  • Example 6 0.019 0.3 0.46 17.3 6.3 0.25 0.1 0.15 0.21 0 800
  • Example 7 0.02 0.41 0.99 17.3 7.04 0.25 0.1 0.15 0.2 0 800
  • Example 8 0.019 0.3 0.46 17.3 6.3 0.25 0.1 0.15 0.21 0 850
  • Example 9 0.02 0.41 0.99 17.3 7.04 0.25 0.1 0.15 0.2 0 850 Comparative Example 1
  • Equation (1) of the cold-annealed materials prepared as described above are shown in Table 2 below.
  • Equation (1) above [C], [Si], [Mn], [Cr], [Ni], [N], and [Nb] represent weight percentages (wt%) of respective elements
  • Md30 refers to values defined by 551-462([C]+[N])-9.2*[Si]-8.1*[Mn]-13.7*[Cr]-29([Ni]+[Cu])-18.5*[Mo]-68([Nb]+[V])
  • Temp refers to cold annealing temperature (°C).
  • the prepared cold-annealed material was prepared as a sample having a thickness of 0.1 to 3.0 mm. Subsequently, average grain sizes d, fractions of the unrecrystallized area, yield strengths, tensile strengths, elongations, and yield ratios of the thickness central regions of the samples were measured and shown in Table 2 below.
  • the average grain size d and the fraction of the unrecrystallized area were measured by analyzing orientations of the thickness central region by using an electron backscatter diffraction (EBSD) pattern analyzer with Model No. of e-Flash FS.
  • EBSD electron backscatter diffraction
  • the yield strength, tensile strength, and elongation were measured by using a universal test machine (UTM).
  • the yield ratio refers to a value obtained by dividing a yield strength by a tensile strength.
  • Example 2 63.2 0.80 1.0 0 930 1083 20.8 0.86
  • Example 3 23.3 0.98 0.5 0 1113 1172 21.8 0.95
  • the S2 vales of Equation (1) satisfied 0.8 or more and the average grain sizes d satisfied 5 ⁇ m or less.
  • the fraction of a unrecrystallized area in a band form satisfied 10% or less.
  • Examples 1 to 9 satisfied a yield strength of at least 700 MPa but not more than 1113 MPa, an elongation of at least 20% but not more than 41.2%, and a yield ratio of at least 0.8 but not more than 0.96. That is, Examples 1 to 9 simultaneously satisfied the high strength, high elongation, and high yield ratio.
  • Comparative Examples 3 and 8 exhibited low average grain sizes d and satisfied a yield strength of at least 700 MPa but not more than 1113 MPa. However, in Comparative Examples 3 and 8, the tensile strength was relatively high compared to the yield strength. Accordingly, Comparative Examples 3 and 8 did not satisfy the yield ratio of at least 0.8 but not more than 0.96.
  • the ⁇ value represented by Equation (1) of 0.8 or more was not satisfied in Comparative Examples 4 to 7 and 9 to 39. Accordingly, the yield strength of at least 700 MPa but not more than 1113 MPa and the yield ratio of at least 0.8 but not more than 0.96 were not satisfied in Comparative Examples 4 to 7 and 9 to 39.
  • Comparative Examples 27 to 39 exhibited high cold annealing temperatures. Accordingly, the average grain sizes d of 5 ⁇ m or less were not satisfied in Comparative Examples 27 to 39.
  • FIGS. 1 and 2 are graphs illustrating stress-deformation curves of an example and a comparative example.
  • FIG. 1 is a graph of Example 1
  • FIG. 2 is a graph of Comparative Example 3.
  • the austenitic stainless steel according to an embodiment of the present disclosure may simultaneously satisfy the high strength, the high elongation, and the high yield ratio because a stress change according to the degree of deformation is not relatively large.
  • FIGS. 3 and 4 are images of microstructures of thickness central regions of an example and a comparative example obtained by an electron backscatter diffraction (EBSD) pattern analyzer.
  • FIG. 3 is an image of Example 3
  • FIG. 4 is an image of Comparative Example 2.
  • EBSD electron backscatter diffraction
  • a ultrafine austenitic stainless steel simultaneously satisfying a high strength, s high elongation, and a high yield ratio and a method for manufacturing the same may be provided.

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EP22837831.1A 2021-07-06 2022-06-09 Austenitic stainless steel and manufacturing method thereof Pending EP4343014A1 (en)

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KR1020210088182A KR20230007619A (ko) 2021-07-06 2021-07-06 오스테나이트계 스테인리스강 및 그 제조방법
PCT/KR2022/008142 WO2023282477A1 (ko) 2021-07-06 2022-06-09 오스테나이트계 스테인리스강 및 그 제조방법

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KR101620252B1 (ko) * 2012-08-20 2016-05-12 신닛테츠스미킨 카부시키카이샤 스테인리스 강판과 그 제조 방법
JP6423138B2 (ja) * 2013-06-14 2018-11-14 新日鐵住金ステンレス株式会社 酸化皮膜の密着性に優れた燃料改質器用オーステナイト系ステンレス鋼およびその製造方法
SG11201701799RA (en) 2014-09-17 2017-04-27 Nippon Steel & Sumitomo Metal Corp Austenitic stainless steel sheet
KR101952054B1 (ko) * 2014-09-25 2019-02-25 신닛테츠스미킨 카부시키카이샤 오스테나이트계 스테인리스 강판 및 그것의 제조 방법
JP2020050940A (ja) 2018-09-28 2020-04-02 国立研究開発法人日本原子力研究開発機構 オーステナイト系微細粒ステンレス鋼の製造方法
EP3862452A4 (en) * 2018-10-04 2022-06-29 Nippon Steel Corporation Austenitic stainless steel sheet and method for producing same

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