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 PDFInfo
- 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
- Authority
- EP
- European Patent Office
- Prior art keywords
- less
- content
- steel plate
- steel
- chemical composition
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 81
- 239000010959 steel Substances 0.000 title claims abstract description 81
- 238000004519 manufacturing process Methods 0.000 title description 7
- 230000009467 reduction Effects 0.000 claims abstract description 41
- 239000000203 mixture Substances 0.000 claims abstract description 19
- 239000000126 substance Substances 0.000 claims abstract description 19
- 239000012535 impurity Substances 0.000 claims abstract description 5
- 229910052742 iron Inorganic materials 0.000 claims abstract description 3
- 238000005096 rolling process Methods 0.000 claims description 33
- 238000010438 heat treatment Methods 0.000 claims description 13
- 239000002994 raw material Substances 0.000 claims description 12
- 238000005098 hot rolling Methods 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- 229910052799 carbon Inorganic materials 0.000 abstract description 4
- 229910052748 manganese Inorganic materials 0.000 abstract description 4
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 3
- 229910052757 nitrogen Inorganic materials 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 20
- 230000007423 decrease Effects 0.000 description 18
- 230000000694 effects Effects 0.000 description 17
- 239000002244 precipitate Substances 0.000 description 13
- 239000000463 material Substances 0.000 description 9
- 238000005266 casting Methods 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 7
- 238000005260 corrosion Methods 0.000 description 7
- 230000007547 defect Effects 0.000 description 7
- 229910001566 austenite Inorganic materials 0.000 description 6
- 229910052759 nickel Inorganic materials 0.000 description 6
- 238000003860 storage Methods 0.000 description 6
- 238000009864 tensile test Methods 0.000 description 5
- 229910052787 antimony Inorganic materials 0.000 description 4
- 239000010953 base metal Substances 0.000 description 4
- 229910052750 molybdenum Inorganic materials 0.000 description 4
- 150000004767 nitrides Chemical class 0.000 description 4
- 238000009628 steelmaking Methods 0.000 description 4
- 229910052718 tin Inorganic materials 0.000 description 4
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- 238000005336 cracking Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 150000001247 metal acetylides Chemical class 0.000 description 3
- 230000000877 morphologic effect Effects 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 238000005728 strengthening Methods 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 229910000746 Structural steel Inorganic materials 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 239000003949 liquefied natural gas Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052721 tungsten Inorganic materials 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- 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
- 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
- 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
- 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
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
-
- 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
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- C—CHEMISTRY; METALLURGY
- 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
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- 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 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.
Landscapes
- 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)
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 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP3835445A1 true EP3835445A1 (fr) | 2021-06-16 |
EP3835445A4 EP3835445A4 (fr) | 2021-08-18 |
Family
ID=67766640
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP18931672.2A Pending EP3835445A4 (fr) | 2018-08-28 | 2018-08-28 | Tôle d'acier et procédé pour la production de celle-ci |
Country Status (9)
Country | Link |
---|---|
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) |
Family Cites Families (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5681656A (en) * | 1979-12-10 | 1981-07-03 | Japan Steel Works Ltd:The | Nonmagnetic steel for cryogenic temperature high magnetic field apparatus |
JPH0813092A (ja) * | 1994-06-30 | 1996-01-16 | Nkk Corp | 被削性および溶接性に優れた高Mn非磁性鋼 |
JP2005325387A (ja) * | 2004-05-13 | 2005-11-24 | Kiyohito Ishida | 低比重鉄合金 |
CN104220617B (zh) | 2011-12-27 | 2016-10-26 | Posco公司 | 具有优异的机械加工性并且在焊接热影响区域具有低温韧性的奥氏体钢,及其制造方法 |
CN104152797A (zh) * | 2014-08-14 | 2014-11-19 | 燕山大学 | 一种低温塑性高锰钢板及其加工方法 |
JP6645103B2 (ja) | 2014-10-22 | 2020-02-12 | 日本製鉄株式会社 | 高Mn鋼材及びその製造方法 |
KR101647227B1 (ko) * | 2014-12-24 | 2016-08-10 | 주식회사 포스코 | 표면 가공 품질이 우수한 저온용 강판 및 그 제조 방법 |
KR20160084529A (ko) | 2015-01-05 | 2016-07-14 | (주)대한솔루션 | 자동차용 연료 필터 인슐레이션 |
JP6693217B2 (ja) | 2015-04-02 | 2020-05-13 | 日本製鉄株式会社 | 極低温用高Mn鋼材 |
JP6801236B2 (ja) * | 2015-06-16 | 2020-12-16 | 日本製鉄株式会社 | 低温水素用オーステナイト系ステンレス鋼及びその製造方法 |
JP6520617B2 (ja) * | 2015-09-30 | 2019-05-29 | 日本製鉄株式会社 | オーステナイト系ステンレス鋼 |
JP6589535B2 (ja) * | 2015-10-06 | 2019-10-16 | 日本製鉄株式会社 | 低温用厚鋼板及びその製造方法 |
JP6728779B2 (ja) * | 2016-03-03 | 2020-07-22 | 日本製鉄株式会社 | 低温用厚鋼板及びその製造方法 |
US20170349983A1 (en) * | 2016-06-06 | 2017-12-07 | Exxonmobil Research And Engineering Company | High strength cryogenic high manganese steels and methods of making the same |
CN106222554A (zh) * | 2016-08-23 | 2016-12-14 | 南京钢铁股份有限公司 | 一种经济型超低温用钢及其制备方法 |
WO2018104984A1 (fr) * | 2016-12-08 | 2018-06-14 | Jfeスチール株式会社 | TÔLE D'ACIER À TENEUR ÉLEVÉE EN Mn ET SON PROCÉDÉ DE PRODUCTION |
-
2018
- 2018-08-28 JP JP2019502270A patent/JP6566166B1/ja active Active
- 2018-08-28 SG SG11202101409TA patent/SG11202101409TA/en unknown
- 2018-08-28 EP EP18931672.2A patent/EP3835445A4/fr active Pending
- 2018-08-28 KR KR1020217005488A patent/KR102524703B1/ko active IP Right Grant
- 2018-08-28 BR BR112021001870-0A patent/BR112021001870A2/pt not_active Application Discontinuation
- 2018-08-28 CN CN201880096307.2A patent/CN112513304A/zh active Pending
- 2018-08-28 MY MYPI2021000812A patent/MY196194A/en unknown
- 2018-08-28 WO PCT/JP2018/031649 patent/WO2020044421A1/fr unknown
-
2021
- 2021-02-26 PH PH12021550411A patent/PH12021550411A1/en unknown
Also Published As
Publication number | Publication date |
---|---|
WO2020044421A1 (fr) | 2020-03-05 |
BR112021001870A2 (pt) | 2021-04-27 |
CN112513304A (zh) | 2021-03-16 |
JPWO2020044421A1 (ja) | 2020-09-10 |
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 |
SG11202101409TA (en) | 2021-03-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4529872B2 (ja) | 高Mn鋼材及びその製造方法 | |
US9790579B2 (en) | High tensile strength steel plate having excellent weld heat-affected zone low-temperature toughness and method for producing same | |
JP5924058B2 (ja) | 溶接熱影響部の低温靭性に優れた高張力鋼板およびその製造方法 | |
KR101846759B1 (ko) | 강판 및 그 제조 방법 | |
CN110050082B (zh) | 高Mn钢板及其制造方法 | |
EP3617337A1 (fr) | ACIER RICHE EN Mn ET SON PROCÉDÉ DE PRODUCTION | |
EP2272994A1 (fr) | Acier ayant une résistance à la traction élevée et son procédé de fabrication | |
EP3722448B1 (fr) | Acier riche en mn, et procédé de fabrication de celui-ci | |
EP3926057A1 (fr) | Acier à haute teneur en mn et procédé de fabrication d'un tel acier | |
JP6856083B2 (ja) | 高Mn鋼およびその製造方法 | |
EP3831973A1 (fr) | Acier à haute teneur en manganèse et son procédé de production | |
CN115210400B (zh) | 钢材及其制造方法、以及罐 | |
JPWO2010038470A1 (ja) | 母材および溶接熱影響部の低温靭性に優れかつ強度異方性の小さい鋼板およびその製造方法 | |
EP3686306B1 (fr) | Tôle d'acier, et procédé de fabrication de celle-ci | |
KR20140023787A (ko) | 저온 인성이 우수한 저탄소 고강도 강판 및 그 제조방법 | |
RU2653954C2 (ru) | Способ производства толстолистового проката для изготовления электросварных газонефтепроводных труб большого диаметра категории прочности х42-х56, стойких против индуцированного водородом растрескивания в h2s -содержащих средах | |
EP3730655A1 (fr) | Tôle d'acier à haute résistance et son procédé de fabrication | |
JPWO2019050010A1 (ja) | 鋼板およびその製造方法 | |
JP2010090406A (ja) | 低降伏比低温用鋼、およびその製造方法 | |
EP3378962A1 (fr) | Acier pour soudage à apport de chaleur élevé | |
EP3835445A1 (fr) | Tôle d'acier et procédé pour la production de celle-ci | |
EP3825436A1 (fr) | Tôle d'acier et procédé de production de celle-ci | |
WO2019168172A1 (fr) | ACIER RICHE EN Mn, ET PROCÉDÉ DE FABRICATION DE CELUI-CI | |
JP7273298B2 (ja) | 低温靱性に優れる圧力容器用鋼板 | |
TW202009314A (zh) | 鋼板及其製造方法 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE |
|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE |
|
17P | Request for examination filed |
Effective date: 20210309 |
|
AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
A4 | Supplementary search report drawn up and despatched |
Effective date: 20210721 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: C22C 38/00 20060101AFI20210715BHEP Ipc: C21D 8/00 20060101ALI20210715BHEP Ipc: C22C 38/38 20060101ALI20210715BHEP Ipc: C22C 38/58 20060101ALI20210715BHEP Ipc: C22C 38/02 20060101ALI20210715BHEP Ipc: C22C 38/22 20060101ALI20210715BHEP Ipc: C22C 38/24 20060101ALI20210715BHEP Ipc: C22C 38/26 20060101ALI20210715BHEP Ipc: C22C 38/28 20060101ALI20210715BHEP Ipc: C22C 38/32 20060101ALI20210715BHEP Ipc: C22C 38/54 20060101ALI20210715BHEP Ipc: C22C 38/60 20060101ALI20210715BHEP Ipc: C21D 8/02 20060101ALI20210715BHEP |
|
DAV | Request for validation of the european patent (deleted) | ||
DAX | Request for extension of the european patent (deleted) | ||
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
17Q | First examination report despatched |
Effective date: 20231005 |