EP3835445A1 - Tôle d'acier et procédé pour la production de celle-ci - Google Patents

Tôle d'acier et procédé pour la production de celle-ci Download PDF

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Publication number
EP3835445A1
EP3835445A1 EP18931672.2A EP18931672A EP3835445A1 EP 3835445 A1 EP3835445 A1 EP 3835445A1 EP 18931672 A EP18931672 A EP 18931672A EP 3835445 A1 EP3835445 A1 EP 3835445A1
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content
steel plate
steel
chemical composition
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EP18931672.2A
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German (de)
English (en)
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EP3835445A4 (fr
Inventor
Shigeki Kitsuya
Koichi Nakashima
Keiji Ueda
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JFE Steel Corp
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JFE Steel Corp
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Publication of EP3835445A1 publication Critical patent/EP3835445A1/fr
Publication of EP3835445A4 publication Critical patent/EP3835445A4/fr
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/002Heat treatment of ferrous alloys containing Cr
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D6/00Heat treatment of ferrous alloys
    • C21D6/005Heat treatment of ferrous alloys containing Mn
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021Modifying 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
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263Modifying 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
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/001Ferrous alloys, e.g. steel alloys containing N
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/002Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/008Ferrous alloys, e.g. steel alloys containing tin
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/22Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/24Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/26Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/28Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/32Ferrous alloys, e.g. steel alloys containing chromium with boron
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/54Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/18Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/58Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/60Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D2211/00Microstructure comprising significant phases
    • C21D2211/001Austenite

Definitions

  • the present disclosure relates to a steel plate having particularly excellent mid-thickness part property and suitable for structural steel used in very-low-temperature environments such as liquefied gas storage tanks, and a method of producing the same.
  • hot-rolled steel plates used for such structures are required to have excellent toughness at very low temperatures as well as excellent strength.
  • a hot-rolled steel plate used for a liquefied natural gas storage needs to have excellent toughness in a temperature range lower than -164 °C which is the boiling point of liquefied natural gas. If the low-temperature toughness of the steel plate used for the very-low-temperature storage structure is insufficient, the safety of the very-low-temperature storage structure is likely to be undermined. There is thus strong need to improve the low-temperature toughness of the steel plate used.
  • austenitic stainless steel plates having austenite microstructure which is not embrittled at very low temperatures 9 % Ni steel plates, and 5000 series aluminum alloys have been conventionally used.
  • due to high alloy costs or production costs of these metal materials there has been demand for a steel plate that is inexpensive and has excellent very-low-temperature toughness.
  • studies have been conducted to use, as a new steel plate to replace conventional steels for very low temperature use, high-Mn steel containing a large amount of Mn which is a relatively inexpensive austenite-stabilizing element and having austenite microstructure, as a structural steel plate in very-low-temperature environments.
  • JP 2015-508452 A discloses a steel material that contains Mn: 15 % to 35 %, Cu: 5 % or less, and appropriate amounts of C and Cr to improve the machinability by cutting and the Charpy impact property of a heat-affected zone at -196 °C.
  • JP 2016-84529 A discloses a high-Mn steel material that contains C: 0.25 % to 0.75 %, Si: 0.05 % to 1.0 %, Mn: more than 20 % and 35 % or less, Ni: 0.1 % or more and less than 7.0 %, and Cr: 0.1 % or more and less than 8.0 % to improve the low-temperature toughness.
  • JP 2016-196703 A discloses a high-Mn steel material that contains C: 0.001 % to 0.80 %, Mn: 15 % to 35 %, and elements such as Cr, Ti, Si, Al, Mg, Ca, and REM to improve the very-low-temperature toughness of base metal and welds.
  • High-Mn steel is high-alloy as compared with typical carbon steel, and accordingly has a low melting point. Moreover, its viscosity around the melting point is high. High-Mn steel is thus more susceptible to coarse casting defects than carbon steel. If casting defects remain in a product, in the case where tensile stress acts in the thickness direction of a steel plate of a cross joint or the like, the product may fracture, leading to a collapse of the structure.
  • a steel plate according to one of the disclosed embodiments will be described in detail below.
  • the present disclosure is not limited to the embodiment described below.
  • the C content needs to be 0.20 % or more. If the C content is more than 0.70 %, C segregates to the mid-thickness part and facilitates excessive precipitation of Cr carbides and Nb-, V-, and Ti-based carbides, and consequently the low-temperature toughness decreases and the reduction of area decreases.
  • the C content is therefore 0.20 % or more and 0.70 % or less.
  • the C content is preferably 0.25 % or more.
  • the C content is preferably 0.60 % or less.
  • Si 0.05 % or more and 1.0 % or less
  • the Si acts as a deoxidizer, and not only is necessary for steelmaking but also has an effect of strengthening the steel plate through solid solution strengthening by dissolving in the steel.
  • the Si content needs to be 0.05 % or more. If the Si content is more than 1.0 %, the weldability and the surface characteristics degrade. The Si content is therefore 0.05 % or more and 1.0 % or less. The Si content is preferably 0.07 % or more. The Si content is preferably 0.5 % or less.
  • Mn 15 % or more and 35 % or less
  • Mn is a relatively inexpensive austenite-stabilizing element.
  • Mn is an important element for achieving both the strength and the very-low-temperature toughness.
  • the Mn content needs to be 15 % or more. If the Mn content is more than 35 %, the effect of improving the very-low-temperature toughness is saturated, and the alloy costs increase. Moreover, the weldability and the cuttability degrade. Furthermore, segregation is facilitated, leading to lower very-low-temperature toughness, degraded tensile property in the thickness direction, and stress corrosion cracking.
  • the Mn content is therefore 15 % or more and 35 % or less.
  • the Mn content is preferably 18 % or more.
  • the Mn content is preferably 28 % or less.
  • Al acts as a deoxidizer, and is most generally used in the molten steel deoxidation process for steel plates. Al also has an effect of suppressing a decrease in toughness due to solute N reduction by fixing solute N in the steel and forming AlN. To achieve the effects, the Al content needs to be 0.01 % or more. If the Al content is more than 0.1 %, Al diffuses into a weld metal portion during welding and decreases the toughness of the weld metal. The Al content is therefore 0.1 % or less. The Al content is preferably 0.07 % or less. The Al content is more preferably 0.02 % or more. The Al content is more preferably 0.06 % or less.
  • Cr is an element necessary to improve the low-temperature toughness and the corrosion resistance of high-Mn steel. Meanwhile, Cr may form nitrides, carbides, carbonitrides, or the like which precipitate during rolling. Such precipitates become a corrosion initiation point or a fracture origin to thus cause a decrease in low-temperature toughness.
  • the upper limit of the Cr content is therefore set to 8.0 %.
  • the Cr content is preferably 1.0 % or more.
  • the Cr content is preferably 6.0 % or less.
  • the Cr content is more preferably 1.5 % or more.
  • the Cr content is more preferably 5.5 % or less.
  • N 0.0010 % or more and 0.0500 % or less
  • N is an austenite-stabilizing element, and is effective in improving the very-low-temperature toughness. N also has an effect of combining with Nb, V, and Ti to form nitrides or carbonitrides which finely precipitate and suppress stress corrosion cracking as a diffusible hydrogen trapping site. To achieve the effects, the N content needs to be 0.0010 % or more. If the N content is more than 0.0500 %, excessive formation of nitrides or carbonitrides is facilitated, as a result of which not only the amount of solute element decreases and the corrosion resistance decreases but also the toughness decreases. The N content is therefore 0.0010 % or more and 0.0500 % or less. The N content is preferably 0.0020 % or more. The N content is preferably 0.0200 % or less.
  • the P content is more than 0.03 %, P segregates to grain boundaries and decreases the grain boundary strength, and forms a fracture origin in some cases. It is therefore desirable to reduce the P content as much as possible, with its upper limit being set to 0.03 %. Thus, the P content is 0.03 % or less. Since lower P content contributes to improved properties, the P content is preferably 0.025 % or less, and more preferably 0.020 % or less. Reducing the P content to less than 0.0005 % requires considerable steelmaking costs. Hence, the P content is preferably 0.0005 % or more from the viewpoint of economic efficiency.
  • S forms MnS in the steel and significantly degrades the low-temperature toughness and the reduction of area during tension in the thickness direction. It is therefore desirable to reduce the S content as much as possible, with its upper limit being set to 0.005 %.
  • the S content is preferably 0.002 % or less. Reducing the S content to less than 0.0001 % requires considerable steelmaking costs. Hence, the S content is preferably 0.0001 % or more from the viewpoint of economic efficiency.
  • the balance other than the components described above consists of Fe and inevitable impurities.
  • the inevitable impurities include Zr, As, and the like.
  • the chemical composition of the steel plate according to one of the disclosed embodiments may optionally contain the following elements in addition to the above-described essential elements, for the purpose of further improving the strength and the low-temperature toughness.
  • Nb 0.003 % or more and 0.030 % or less
  • the Nb content is an element effective in improving the strength of the steel plate.
  • the Nb content is preferably 0.003 % or more. If the Nb content is more than 0.030 %, coarse carbonitrides may precipitate and form a fracture origin, as a result of which the tensile property in the thickness direction degrades. In addition, precipitates may coarsen and cause a decrease in base metal toughness. Accordingly, in the case of containing Nb, the Nb content is preferably 0.003 % or more and 0.030 % or less.
  • the Nb content is more preferably 0.005 % or more, and further preferably 0.007 % or more.
  • the Nb content is more preferably 0.025 % or less, and further preferably 0.022 % or less.
  • V 0.01 % or more and 0.10 % or less
  • V is an element effective in improving the strength of the steel plate.
  • the V content is preferably 0.01 % or more. If the V content is more than 0.10 %, coarse carbonitrides may precipitate and form a fracture origin. In addition, precipitates may coarsen and cause a decrease in base metal toughness. Accordingly, in the case of containing V, the V content is preferably 0.01 % or more and 0.10 % or less. The V content is more preferably 0.02 % or more, and further preferably 0.03 % or more. The V content is more preferably 0.09 % or less, and further preferably 0.08 % or less.
  • Ti is an element that forms nitrides or carbonitrides which precipitate, and is effective in improving the strength of the steel plate.
  • the Ti content is preferably 0.003 % or more. If the Ti content is more than 0.040 %, precipitates may coarsen and cause a decrease in base metal toughness. In addition, coarse carbonitrides may precipitate and form a fracture origin. Accordingly, in the case of containing Ti, the Ti content is preferably 0.003 % or more and 0.040 % or less.
  • the Ti content is more preferably 0.005 % or more, and further preferably 0.007 % or more.
  • the Ti content is more preferably 0.035 % or less, and further preferably 0.032 % or less.
  • the B is an element that enhances the austenite grain boundary strength and is effective in improving the very-low-temperature toughness.
  • the B content is preferably 0.0003 % or more. If the B content is more than 0.0100 %, coarse B precipitates form, and the toughness decreases. The B content is therefore preferably 0.0100 % or less. The B content is more preferably 0.0030 % or less.
  • the chemical composition of the steel plate according to one of the disclosed embodiments may optionally further contain the following elements.
  • Cu, Ni, Sn, Sb, Mo, and W are each an element that, when added in combination with Cr, improves the corrosion resistance of the high-Mn steel.
  • each of these elements is realized in the case where the element is present together with Cr in the high-Mn steel, and is exhibited when the content of the element is not less than the foregoing upper limit. If the content of the element is more than the foregoing upper limit, the weldability and the toughness decrease, and a cost disadvantage ensues.
  • Cu, Ni, Sn, Sb, Mo, and W are each preferably added in the foregoing range. More preferably, the Cu content is 0.02 % or more and 0.50 % or less, the Ni content is 0.02 % or more and 0.40 % or less, the Sn content is 0.02 % or more and 0.25 % or less, the Sb content is 0.02 % or more and 0.25 % or less, the Mo content is 0.05 % or more and 1.50 % or less, and the W content is 0.05 % or more and 1.50 % or less.
  • the chemical composition of the steel plate according to one of the disclosed embodiments may optionally further contain the following elements.
  • Ca, Mg, and REM are each an element useful for morphological control of inclusions such as MnS, and may be optionally contained.
  • Morphological control of inclusions means turning elongated sulfide-based inclusions into granular inclusions. Through such morphological control of inclusions, the tensile property in the thickness direction, the toughness, and the sulfide stress corrosion cracking resistance can be improved.
  • the Ca content and the Mg content are each preferably 0.0005 % or more, and the REM content is preferably 0.0010 % or more.
  • the Ca content is preferably 0.0050 % or less.
  • the Mg content is preferably 0.0100 % or less.
  • the REM content is preferably 0.0200 % or less. More preferably, the Ca content is 0.0010 % or more and 0.0040 % or less, the Mg content is 0.0010 % or more and 0.0040 % or less, and the REM content is 0.0020 % or more and 0.0150 % or less.
  • the steel plate having the foregoing chemical composition has reduction of area in the thickness direction of 30 % or more. If the reduction of area in the thickness direction is less than 30 %, for example, a cross weld joint fractures and the soundness of the structure is significantly impaired.
  • the production conditions for the steel plate according to one of the disclosed embodiments will be described below.
  • the steel plate according to one of the disclosed embodiments can be produced by: heating a steel raw material having the foregoing chemical composition to 1000 °C or more and 1300 °C or less; and thereafter subjecting the steel raw material to hot rolling with a rolling reduction ratio of 3 or more, wherein a rolling reduction of each of at least two passes of final three passes is 10 % or more.
  • temperature "°C" denotes the temperature in the mid-thickness part.
  • Heating temperature of steel raw material 1000 °C or more and 1300 °C or less
  • the steel raw material is heated to 1000 °C or more, in order to dissolve precipitates in the microstructure and homogenize the crystal grain size and the like.
  • the heating temperature is 1000 °C or more and 1300 °C or less. If the heating temperature is less than 1000 °C, precipitates do not dissolve sufficiently, making it impossible to obtain desired properties. If the heating temperature is more than 1300 °C, the material properties degrade due to coarsening of crystal grains. Moreover, excessive energy is required, so that the productivity decreases.
  • the upper limit of the heating temperature is therefore 1300 °C.
  • the heating temperature is preferably 1050 °C or more.
  • the heating temperature is preferably 1250 °C or less.
  • the heating temperature is more preferably 1100 °C or more.
  • the heating temperature is more preferably 1250 °C or less.
  • the steel raw material may be a raw material produced by a usual method such as a continuously-cast slab, an ingot-cast slab, or a bloom.
  • the rolling reduction ratio in the hot rolling is less than 3, it is difficult to suppress a decrease in tensile property in the thickness direction by pressure bonding of casting defects. Moreover, the promotion of recrystallization by the rolling to achieve homogenization is insufficient, and coarse austenite grains remain, as a result of which properties such as strength and toughness degrade.
  • the rolling reduction ratio is therefore limited to 3 or more.
  • the rolling reduction ratio is preferably 4 or more, and more preferably 5 or more. Although no upper limit is placed on the rolling reduction ratio, the rolling reduction ratio is preferably 50 or less. If the rolling reduction ratio is more than 50, the anisotropy of mechanical properties increases significantly.
  • the rolling reduction ratio in the hot rolling is defined as "(the thickness of the rolling raw material)/(the thickness of the steel plate after the rolling)”.
  • the rolling reduction of each of at least two passes of the final three passes is limited for reliable pressure bonding of casting defects.
  • the rolling reduction of each of all final three passes is preferably 10 % or more. If the rolling reduction of each of at least two passes of the final three passes is less than 10 %, casting defects remain, and the reduction of area in the mid-thickness part decreases.
  • the upper limit is preferably 30 % in terms of production line constraints such as rolling load.
  • water cooling or the like may be performed after the hot rolling.
  • the reduction of area in the thickness direction in the tensile test was evaluated in accordance with JIS G 3199.
  • the test piece shape used was a type A test piece.
  • the tensile strength was evaluated using a round bar tensile test piece collected from a depth position of 1/4 (hereafter referred to as "1/4t part") of the thickness from the steel plate surface.
  • the Charpy absorbed energy at -196 °C was evaluated by taking the average of three Charpy test pieces collected from the 1/4t part.
  • Example (samples No. 1 to No. 14) according to the present disclosure satisfied reduction of area of 30 % or more.
  • Each Comparative Example (samples No. 15 to No. 30) outside the range according to the present disclosure failed to satisfy the foregoing target performance in at least one of tensile strength, absorbed energy, and reduction of area.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
EP18931672.2A 2018-08-28 2018-08-28 Tôle d'acier et procédé pour la production de celle-ci Pending EP3835445A4 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/JP2018/031649 WO2020044421A1 (fr) 2018-08-28 2018-08-28 Tôle d'acier et procédé pour la production de celle-ci

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EP3835445A1 true EP3835445A1 (fr) 2021-06-16
EP3835445A4 EP3835445A4 (fr) 2021-08-18

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EP (1) EP3835445A4 (fr)
JP (1) JP6566166B1 (fr)
KR (1) KR102524703B1 (fr)
CN (1) CN112513304A (fr)
BR (1) BR112021001870A2 (fr)
MY (1) MY196194A (fr)
PH (1) PH12021550411A1 (fr)
SG (1) SG11202101409TA (fr)
WO (1) WO2020044421A1 (fr)

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JPS5681656A (en) * 1979-12-10 1981-07-03 Japan Steel Works Ltd:The Nonmagnetic steel for cryogenic temperature high magnetic field apparatus
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JP2005325387A (ja) * 2004-05-13 2005-11-24 Kiyohito Ishida 低比重鉄合金
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KR102524703B1 (ko) 2023-04-21
PH12021550411A1 (en) 2021-09-20
KR20210035263A (ko) 2021-03-31
MY196194A (en) 2023-03-22
EP3835445A4 (fr) 2021-08-18
JP6566166B1 (ja) 2019-08-28
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