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  • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

Definitions

• the present invention relates to a thick steel plate having excellent cryogenic toughness. Specifically, according to the present invention, even when the Ni content is reduced to about 5.0 to 7.5%, toughness at an extremely low temperature of ⁇ 196 ° C. or less [particularly, toughness in the plate width direction (C direction)] Relates to a good thick steel plate.
• the explanation will focus on thick steel plates (typically storage tanks, transport ships, etc.) for liquefied natural gas (LNG) exposed to the above-mentioned cryogenic temperatures.
• LNG liquefied natural gas
• the present invention is not intended to be limited, and is applied to all thick steel plates used for applications exposed to extremely low temperatures of ⁇ 196 ° C. or less.
• LNG tank steel plates used in LNG storage tanks are required to have high strength and high toughness that can withstand extremely low temperatures of -196 ° C.
• Ni improves the hardness-toughness balance particularly at low temperatures.
• thick steel plates containing about 9% Ni (9% Ni steel) have been used as the thick steel plates used in the above applications.
• the cost of Ni has increased in recent years, the development of a thick steel plate excellent in cryogenic toughness even with a low Ni content of less than 9% has been underway.
• Non-Patent Document 1 describes the effect of ⁇ - ⁇ 2 phase coexistence heat treatment on the low temperature toughness of 6% Ni steel. More specifically, by applying heat treatment (L treatment) in the ⁇ - ⁇ 2 phase coexistence region (between A c1 and A c3 ) before tempering treatment, a large amount of fine and extremely low temperature impact loads are applied. Further, it is described that stable retained austenite is generated, and cryogenic toughness at ⁇ 196 ° C. which is equal to or higher than that of 9% Ni steel subjected to normal quenching and tempering treatment can be secured. However, although the cryogenic toughness in the rolling direction (L direction) is excellent, the cryogenic toughness in the sheet width direction (C direction) generally tends to be inferior to that in the L direction. There is no description of the brittle fracture surface ratio.
• Patent Document 1 discloses that steel containing 4.0 to 10% Ni and whose austenite grain size is controlled within a predetermined range is hot-rolled and then heated between A c1 and A c3.
• a method is described in which a cooling treatment (corresponding to the L treatment described in Non-Patent Document 1 above) is repeated once or twice or more and then tempered at a temperature not higher than the Ac1 transformation point.
• Patent Document 2 discloses that the steel containing 4.0 to 10% Ni and the size of AlN before hot rolling is 1 ⁇ m or less is similar to the heat treatment (L treatment ⁇ firing) described above.
• a method for performing the return processing is described.
• Non-Patent Document 2 describes the development of 6% Ni steel for LNG tanks combining the above-mentioned L treatment (two-phase quenching treatment) and TMCP. According to this document, although it is described that the toughness in the rolling direction (L direction) shows a high value, the toughness value in the sheet width direction (C direction) is not described.
• Patent Document 3 a steel sheet having a yield strength at room temperature of 590 MPa or more in a Ni steel of more than 5.0% and less than 8.0% is assumed to be as resistant as 9% Ni steel even in a use environment. It describes a Ni-reduced steel plate for low temperature with excellent fracture safety and a method for producing the same.
• the yield point in the low temperature environment which is use temperature can be raised reliably, fracture safety will be improved (that is, high toughness can be obtained in a low temperature environment).
• the steel ingot is heated at a low temperature in a short time, and in the rolling process, the thickness of the steel ingot at the end of the rough rolling is the product thickness (thickness after finish rolling).
• the steel sheet is reduced to 3 to 8 times the thickness of the steel sheet. Further, in the examples, rolling is performed from a slab thickness of 300 mm to a finishing thickness of 50 mm or less (mostly to a finishing thickness of less than 50 mm). Thus, by securing a relatively high reduction ratio, the residual ⁇ fraction and the fineness are reduced. Combined with a matrix structure, it achieves low temperature toughness comparable to 9% Ni steel. However, the TS at room temperature of the thick steel plate of Patent Document 3 is 741 MPa at the maximum.
• Patent Document 3 although the absorbed energy in the C direction is described, there is no description of the brittle fracture surface ratio. Moreover, TS at room temperature in Patent Document 3 is about 741 MPa at the maximum.
• Japanese Unexamined Patent Publication No. 49-13581 Japanese Laid-Open Patent Publication No. 51-13308 Japanese Unexamined Patent Publication No. 2011-241419
• the brittle fracture surface ratio indicates the ratio of brittle fracture that occurs when a load is applied in the Charpy impact test. At the site where brittle fracture occurs, the energy absorbed by the steel material until the fracture is significantly reduced, and the fracture proceeds easily. Therefore, in the cryogenic toughness improvement technology, the general-purpose Charpy impact value (vE In addition to the improvement of -196 ), the brittle fracture surface ratio should be 10% or less, which is an extremely important requirement.
• vE general-purpose Charpy impact value
• the brittle fracture surface ratio should be 10% or less, which is an extremely important requirement.
• a technique that satisfies the above requirement for the brittle fracture surface ratio in a high-strength thick steel plate having a high base metal strength as described above has not yet been proposed.
• the present invention has been made in view of the above circumstances, and its purpose is to achieve cryogenic toughness at ⁇ 196 ° C. (particularly in the C direction) in Ni steel having a Ni content of about 5.0 to 7.5%.
• An object of the present invention is to provide a high-strength thick steel plate that is excellent in low-temperature toughness and can realize a brittle fracture surface ratio ⁇ 10%, and a method for producing the same.
• the thick steel plate having excellent cryogenic toughness according to the present invention that can solve the above problems is mass%, C: 0.02 to 0.10%, Si: 0.40% or less (excluding 0%) Mn: 0.50 to 2.0%, P: 0.007% or less (not including 0%), S: 0.007% or less (not including 0%), Al: 0.005 to 0.
• Di value ([C] / 10) 0.5 ⁇ (1 + 0.7 ⁇ [Si]) ⁇ (1 + 3.33 ⁇ [Mn]) ⁇ (1 + 0.35 ⁇ [Cu]) ⁇ (1 + 0.36 ⁇ [ Ni]) ⁇ (1 + 2.16 ⁇ [Cr]) ⁇ (1 + 3 ⁇ [Mo]) ⁇ (1 + 1.75 ⁇ [V]) ⁇ 1.115
• [] means the content (% by mass) of each component in the steel)
• Residual ⁇ stabilization parameter (365 ⁇ ⁇ C> + 39 ⁇ ⁇ Mn> + 30 ⁇ ⁇ Al> + 10 ⁇ ⁇ Cu> + 17 ⁇ ⁇ Ni> + 20 ⁇ ⁇ Cr> + 5 ⁇ ⁇ Mo> + 35 ⁇ ⁇ V>) / 100 (2) (In the formula, ⁇ > means the content (% by mass) of each component contained in the retained austenite existing at -196 ° C.)
• the volume fraction of the residual ⁇ phase and the residual ⁇ stability calculated based on the following equation (3) composed of the volume fraction of the residual ⁇ phase and the residual ⁇ stabilization parameter:
• the activation parameter is 40 or less.
• Volume fraction of residual ⁇ / residual ⁇ stabilization parameter 10 / (volume fraction of residual ⁇ phase ⁇ residual ⁇ stabilization parameter) 1/2 (3)
• the Mn concentration in the residual ⁇ is controlled in place of the residual ⁇ stabilization parameter after defining the element content, Di value, and residual ⁇ volume fraction in the above-mentioned thick steel plate within a more limited range.
• This is also a preferred embodiment of the present invention because it is possible to exhibit extremely low temperature toughness after obtaining a higher base metal strength.
• C 0.02 to 0.10%, Si: 0.40% or less (not including 0%), Mn: 0.6 to 2.0%, P: 0.0. 007% or less (excluding 0%), S: 0.007% or less (not including 0%), Al: 0.005 to 0.050%, Ni: 5.0 to 7.5%, N: Contains 0.010% or less (excluding 0%), Mo: 0.30 to 1.0%, Cr: 1.20% or less (excluding 0%), the balance being iron and inevitable impurities
• a thick steel plate The Di value determined on the basis of the formula (1) composed of components in steel is more than 5.0, The residual austenite phase (residual ⁇ ) present at ⁇ 196 ° C.
• the steel sheet further contains Cu: 1.0% or less (excluding 0%).
• the steel sheet further includes Ti: 0.025% or less (excluding 0%), Nb: 0.100% or less (not including 0%), and V: 0.50. % Or less (not including 0%).
• the steel sheet further contains B: 0.0050% or less (excluding 0%).
• the steel sheet is further selected from the group consisting of Ca: 0.0030% or less (excluding 0%) and REM: 0.0050% or less (excluding 0%). Containing at least one kind.
• the steel plate further contains Zr: 0.005% or less (excluding 0%).
• the method for producing a thick steel plate according to the present invention according to claim 1 or 2 that has solved the above-described problem is a heat treatment (L treatment) in an ⁇ - ⁇ 2 phase coexistence region (between A c1 and A c3 ).
• the L parameter calculated based on the following formula (5) composed of the temperature (L treatment temperature) and A c1 and A c3 in the steel is 0.25 or more and 0.45 or less, and Adjusting the L treatment temperature and the steel component so that the ⁇ L parameter calculated based on the following formula (6) composed of the L parameter and the steel component is 7 or less: , L treatment, water cooling to room temperature, and tempering treatment (T treatment) are carried out for 10 to 60 minutes at a temperature of Ac1 or lower.
• the L parameter calculated based on the formula (5) is 0.6 or more and 1.1 or less.
• the L treatment temperature and the steel components are adjusted so that the ⁇ L parameter calculated based on the equation (6) is 0 or less.
• Ni steel having a Ni content of about 5.0 to 7.5% even if the base metal strength is high (specifically, tensile strength TS> 741 MPa, yield strength YS> 590 MPa, preferably TS ⁇ 830 MPa, YS ⁇ 690 MPa), excellent in cryogenic toughness at ⁇ 196 ° C. or less (particularly, cryogenic toughness in the C direction), brittle fracture surface ratio at ⁇ 196 ° C. ⁇ 10% (preferably ⁇ It was possible to provide a high-strength thick steel plate that satisfies the brittle fracture surface ratio ⁇ 50% at 233 ° C.
• the inventors of the present invention have a Ni content of 7.5% or less, and when performing a Charpy impact absorption test in the C direction, the brittle fracture surface ratio at ⁇ 196 ° C. is 10% or less, the tensile strength TS> 741 MPa, In order to provide a thick steel plate that satisfies the yield strength YS> 590 MPa, investigations were made.
• the residual ⁇ form the following (A), (b), and lambda L Parameters following (c)], by the following control, in Charpy impact absorption test, not transformed into martensite It was found that a stable residual ⁇ that is plastically deformed can be ensured, and that excellent cryogenic toughness can be obtained.
• A From the viewpoint of plastic deformation without being transformed into martensite during impact at extremely low temperature, and securing stable residual ⁇ useful for improving toughness (enhancing the stability of residual ⁇ ), The Di value [see the above formula (1)] is controlled by an appropriate balance of the above.
• Controlling (preferably, the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter [refer to the above equation (3)] composed of the volume fraction of residual ⁇ and the above-mentioned residual ⁇ stabilization parameter are set to 40 or less.
• C Control the ⁇ l parameter determined by the component (Mn, Cr, Mo) and the L processing temperature as shown in the above equation (5).
• the thick steel plate of the present invention is, by mass%, C: 0.02 to 0.10%, Si: 0.40% or less (excluding 0%), Mn: 0.50 to 2.0%, P: 0.007% or less (not including 0%), S: 0.007% or less (not including 0%), Al: 0.005 to 0.050%, Ni: 5.0 to 7.5 %, N: 0.010% or less (not including 0%), Cr: 1.20% or less (not including 0%), and Mo: 1.0% or less (not including 0%) )
• C 0.02 to 0.10%
• C is an element essential for securing strength and retained austenite.
• the lower limit of the C amount is set to 0.02% or more.
• the minimum with the preferable amount of C is 0.03% or more, More preferably, it is 0.04% or more.
• the upper limit is made 0.10%.
• the upper limit with preferable C amount is 0.08% or less, More preferably, it is 0.06% or less.
• Si 0.40% or less (excluding 0%) Si is an element useful as a deoxidizer. However, if added in excess, the formation of a hard island-like martensite phase is promoted and the cryogenic toughness decreases, so the upper limit is made 0.40% or less.
• the upper limit with the preferable amount of Si is 0.35% or less, More preferably, it is 0.20% or less.
• Mn 0.50 to 2.0%
• Mn is an austenite ( ⁇ ) stabilizing element and is an element contributing to an increase in the amount of residual ⁇ .
• the lower limit of the amount of Mn is set to 0.50%.
• the minimum with the preferable amount of Mn is 0.6% or more, More preferably, it is 0.7% or more.
• the upper limit is made 2.0% or less.
• the upper limit with the preferable amount of Mn is 1.5% or less, More preferably, it is 1.3% or less.
• P 0.007% or less (excluding 0%)
• P is an impurity element causing grain boundary fracture, and its upper limit is made 0.007% or less in order to secure the desired cryogenic toughness.
• the upper limit with preferable P amount is 0.005% or less. The smaller the amount of P, the better. However, it is difficult to make the amount of P 0% industrially.
• S 0.007% or less (excluding 0%) S, like P, is an impurity element causing grain boundary fracture, and its upper limit is made 0.007% or less in order to ensure the desired cryogenic toughness.
• the upper limit with the preferable amount of S is 0.005% or less. The smaller the amount of S, the better. However, it is difficult to make the amount of S 0% industrially.
• Al 0.005 to 0.050%
• Al is an element that promotes desulfurization and fixes nitrogen. If the Al content is insufficient, the concentration of solute sulfur, solute nitrogen, etc. in the steel increases and the cryogenic toughness decreases, so the lower limit is made 0.005% or more.
• the minimum with the preferable amount of Al is 0.010% or more, More preferably, it is 0.015% or more. However, if added excessively, oxides, nitrides, and the like are coarsened and the cryogenic toughness is also lowered, so the upper limit is made 0.050% or less.
• the upper limit with the preferable amount of Al is 0.045% or less, More preferably, it is 0.04% or less.
• Ni 5.0 to 7.5%
• Ni is an essential element for securing retained austenite (residual ⁇ ) useful for improving cryogenic toughness.
• the lower limit of the Ni amount is set to 5.0% or more.
• a preferable lower limit of the Ni amount is 5.2% or more, and more preferably 5.4% or more.
• the upper limit is made 7.5% or less.
• the upper limit of the Ni content is preferably 7.0% or less, more preferably 6.5% or less, still more preferably 6.2% or less, and even more preferably 6.0% or less.
• N 0.010% or less (excluding 0%) N lowers the cryogenic toughness by strain aging, so the upper limit is made 0.010% or less.
• the upper limit with preferable N amount is 0.006% or less, More preferably, it is 0.004% or less.
• Cr at least one selected from the group consisting of 1.20% or less (not including 0%) and Mo: 1.0% or less (not including 0%) Cr and Mo are both strength-enhancing elements. is there. These elements may be added alone or in combination of two kinds. In order to effectively exhibit the above action, the Cr content is 0.05% or more and the Mo content is 0.01% or more. However, if excessively added, the strength is excessively increased and the desired cryogenic toughness cannot be ensured, so the upper limit of the Cr content is 1.20% or less (preferably 1.1% or less, more preferably 0). 0.9% or less, more preferably 0.5% or less) and the upper limit of the Mo amount is 1.0% or less (preferably 0.8% or less, more preferably 0.6% or less).
• the thick steel plate of the present invention contains the above components as basic components, the balance: iron and unavoidable impurities.
• Cu 1.0% or less (excluding 0%)
• Cu is a ⁇ -stabilizing element and is an element that contributes to an increase in the amount of residual ⁇ .
• the upper limit is preferably made 1.0% or less.
• a more preferable upper limit of the amount of Cu is 0.8% or less, and even more preferably 0.7% or less.
• Ti 0.025% or less (not including 0%), Nb: 0.100% or less (not including 0%), and V: 0.50% or less (not including 0%)
• At least one of Ti, Nb, and V is an element that precipitates as carbonitride and increases strength. These elements may be added alone or in combination of two or more. In order to effectively exhibit the above action, it is preferable that the Ti amount is 0.005% or more, the Nb amount is 0.005% or more, and the V amount is 0.005% or more. However, if excessively added, the strength is excessively improved, and the desired cryogenic toughness cannot be ensured.
• the preferable upper limit of Ti amount is 0.025% or less (more preferably 0.018% or less, More preferably 0.015% or less), a preferable upper limit of Nb amount is 0.100% or less (more preferably 0.05% or less, further preferably 0.02% or less), and a preferable upper limit of V amount is 0. .50% or less (more preferably 0.3% or less, and still more preferably 0.2% or less).
• B 0.0050% or less (excluding 0%)
• B is an element that contributes to improving strength by improving hardenability.
• the B content is preferably 0.0005% or more.
• the preferable upper limit of the B amount is 0.0050% or less (more preferably 0.0030% or less, more preferably Is 0.0020% or less).
• Ca 0.0030% or less (excluding 0%) and REM (rare earth element): at least one selected from the group consisting of 0.0050% or less (excluding 0%)
• Ca and REM are solid It is an element that fixes dissolved sulfur and renders sulfides harmless. These elements may be added alone or in combination of two or more. If these contents are insufficient, the solid solution sulfur concentration in the steel increases and the toughness decreases, so the Ca content is 0.0005% or more, the REM content (when the REM described below is contained alone) It is a single content, and when it contains two or more kinds, it is the total amount thereof. However, if excessively added, sulfides, oxides, nitrides, etc.
• the preferable upper limit of Ca content is 0.0030% or less (more preferably 0.0025% or less)
• REM A preferable upper limit of the amount is 0.0050% or less (more preferably 0.0040% or less).
• REM rare earth element
• Sc scandium
• Y yttrium
• a lanthanoid element 15 elements from La with atomic number 57 to Lu with atomic number 71 in the periodic table. These elements can be used alone or in combination of two or more.
• Preferred rare earth elements are Ce and La.
• the addition form of REM is not particularly limited, and may be added in the form of a misch metal mainly containing Ce and La (for example, Ce: about 70%, La: about 20-30%), or Ce, La alone may be added.
• Zr 0.005% or less (excluding 0%)
• Zr is an element that fixes nitrogen. If the Zr content is insufficient, the solid solution N concentration in the steel increases and the toughness decreases, so the Zr content is preferably 0.0005% or more. However, if added excessively, oxides, nitrides, etc. become coarse and the toughness also decreases, so the preferable upper limit of the amount of Zr is made 0.005% or less (more preferably 0.0040% or less).
• volume fraction of residual austenite phase is 2.0 to 12.0% (preferably 4.0 to 12%). 0.0%).
• the volume fraction of the residual ⁇ phase in the entire structure existing at ⁇ 196 ° C. is set to 2.0% or more.
• the residual ⁇ is relatively soft compared to the matrix phase, and if the residual ⁇ amount becomes excessive, YS cannot secure a predetermined value, so the upper limit is made 12.0%.
• the preferable lower limit is 4.0% or more, the more preferable lower limit is 6.0% or more, the preferable upper limit is 11.5% or less, and the more preferable upper limit is 11.0% or less.
• the structure other than the residual ⁇ is not limited at all. Any material that normally exists in thick steel plates may be used. Examples of the structure other than the residual ⁇ include carbides such as bainite, martensite, and cementite.
• Di value ([C] / 10) 0.5 ⁇ (1 + 0.7 ⁇ [Si]) ⁇ (1 + 3.33 ⁇ [Mn]) ⁇ (1 + 0.35 ⁇ [Cu]) ⁇ (1 + 0.36 ⁇ [ Ni]) ⁇ (1 + 2.16 ⁇ [Cr]) ⁇ (1 + 3 ⁇ [Mo]) ⁇ (1 + 1.75 ⁇ [V]) ⁇ 1.115 (1)
• [] means content (mass%) of each component in steel.)
• the above formula (1) relating to the hardenability Di value is described as the Grossmann formula (Trans. Metal. Soc. AIME, 150 (1942), p. 227).
• the larger the amount of the alloy element that constitutes the Di value the easier the firing (the Di value increases) and the finer the structure becomes.
• the greater the Di value the higher the strength, and it becomes easier to ensure the desired strength.
• the Di value is 2.5. It turned out that it should have done above.
• the Di value is such that a fine rolled structure can be obtained even when the rolling reduction of the amorphous region is small, and a sufficient volume fraction of residual ⁇ useful for improving the cryogenic toughness is ensured by the subsequent heat treatment, and the stable residual
• This parameter is useful as a guideline for securing ⁇ .
• the manufacturing conditions described in Patent Document 3 [reduction of reduction rate at low temperature (non-recrystallized region), time limit until the start of cooling, etc.] are relaxed to ensure good characteristics even if the process load is reduced. This is an effective parameter.
• the Di value is set to 2.5 or more.
• the Di value is less than 2.5, a fine structure cannot be sufficiently obtained after rolling, and thus a predetermined amount of residual ⁇ cannot be obtained.
• the residual ⁇ stabilization parameters, volume fraction of residual ⁇ and residual ⁇ stabilization parameters described later cannot be controlled to a predetermined level, a stable residual ⁇ structure cannot be obtained, and the desired cryogenic toughness is ensured.
• a preferable range of the Di value is 3.0 or more.
• the upper limit of the Di value is not particularly limited from the above viewpoint, but considering the viewpoint of cost and the like, and the strength standard range of the current LNG tank steel is 830 MPa or less, it is generally 5.0 or less. Preferably there is.
• Residual ⁇ stabilization parameter (365 ⁇ ⁇ C> + 39 ⁇ ⁇ Mn> + 30 ⁇ ⁇ Al> + 10 ⁇ ⁇ Cu> + 17 ⁇ ⁇ Ni> + 20 ⁇ ⁇ Cr> + 5 ⁇ ⁇ Mo> + 35 ⁇ ⁇ V>) / 100 (2) (In the formula, ⁇ > means the content (% by mass) of each component contained in the retained austenite existing at -196 ° C.)
• the cryogenic toughness As described above, to improve the cryogenic toughness, it is effective to secure a stable residual ⁇ that undergoes plastic deformation without being transformed into martensite during the impact test.
• the residual ⁇ fraction before the impact test and to increase the stability of the residual ⁇ so that it can be plastically deformed without being transformed into martensite even when subjected to an impact.
• the volume fraction of residual ⁇ is defined in the above range.
• the stability of the residual ⁇ existing at ⁇ 196 ° C. was determined by the component in the residual ⁇ existing at ⁇ 196 ° C., and the parameter represented by the above equation (2) It was found effective to control.
• the hardenability generally decreases, so the structure after rolling becomes coarse and the volume fraction of residual ⁇ obtained after heat treatment or the above-mentioned Di value is ensured.
• these requirements are also appropriately controlled by appropriately controlling the residual ⁇ stabilization parameter determined in consideration of the component balance in the residual ⁇ . This residual ⁇ stabilization parameter is derived with reference to the Ms point equation.
• the lower limit of the residual ⁇ stabilization parameter is set to 3.1 or more. Preferably it is 3.3 or more, More preferably, it is 3.5 or more, More preferably, it is 3.7 or more.
• the upper limit of the residual ⁇ stabilization parameter is not particularly limited from the viewpoint of improving cryogenic toughness.
• the above parameters are composed of a residual ⁇ volume fraction and a residual ⁇ stabilization parameter.
• the inventors of the present invention have determined the above parameters, considering that the improvement of the cryogenic toughness is due to the plastic deformation during the cryogenic impact test, and that the distribution of residual ⁇ effective for the improvement of the toughness greatly affects. That is, those having a high volume fraction of residual ⁇ and a large residual ⁇ stabilization parameter are those in which the distance between each residual ⁇ is short and finely dispersed, and they are martensite even at low temperatures. Since it is not transformed into a material and is responsible for plastic deformation, it exhibits good cryogenic toughness.
• the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter are preferably 35 or less, and more preferably 30 or less. From the viewpoint of improving the cryogenic toughness, the lower the parameter, the better.
• the lower limit of the above parameter is not particularly limited in relation to the cryogenic toughness, but is generally 10 or more in consideration of the component system of the present invention.
• the brittle fracture surface ratio can be maintained at a favorable level of 50% or less. Specifically, by reducing the upper limit of the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter as much as possible (generally, 30 or less), the brittle fracture surface ratio at ⁇ 233 ° C. is reduced to 50% or less. Can do.
• the content of the element in the thick steel plate, the Di value, and the limitation to the more limited range of the residual ⁇ volume fraction are: (A) The lower limit of the Mn content is 0.6%. (B) Both Cr and Mo elements are essential additions, and the lower limit of Mo is 0.30%. (C) The Di value is more than 5.0. (D) The upper limit of the residual ⁇ volume fraction existing at ⁇ 196 ° C. is 5.0%. (E) Properly control the balance of the Mn—Ni content in the steel represented by the following formula (4): [Mn] ⁇ 0.31 ⁇ (7.20 ⁇ [Ni]) + 0.50 ⁇ (4) (In the formula, [] means the content (mass%) of each component in the steel.) Means that.
• a steel plate according to the present invention that has already been described, that is, a steel plate that satisfies the brittle fracture surface ratio ⁇ 10% at ⁇ 196 ° C., TS> 741 MPa, and YS> 590 MPa in the C direction Charpy impact absorption test.
• the above (a) to (f) having different configurations will be described.
• the volume fraction of the residual ⁇ phase is preferably high, but the residual ⁇ is relatively soft compared to the matrix phase, and when the residual ⁇ amount is excessive, a predetermined YS and Since TS may not be secured, the upper limit is set to 5.0%.
• a preferred upper limit for the volume fraction of the residual ⁇ phase is 4.8%.
• a preferred lower limit is 3.0%, and a more preferred lower limit is 3.5%.
• the MA size formed at the time of impact has a correlation with the structure size as it is rolled and correlates with the amounts of Ni and Mn in the steel.
• the above formula (4) was specified as the Ni—Mn balance in steel that can ensure the desired strength-toughness balance at extremely low temperatures.
• the preferable Mn concentration in the residual ⁇ existing at ⁇ 196 ° C. is 1.40% or more, more preferably 1.75% or more.
• the preferable upper limit of the Mn concentration in the residual ⁇ is not particularly limited from the relationship with the above action, but considering the range of the amount of Mn in steel and the like, the upper limit is preferably 2.50% or less.
• At least one of (i) the volume fraction of residual ⁇ , (ii) the Mn concentration in residual ⁇ , and (iii) ⁇ L parameter is more appropriate.
• the brittle fracture surface ratio can be maintained at a favorable level of 50% or less even at ⁇ 233 ° C., which is lower than ⁇ 196 ° C. described above.
• the residual ⁇ fraction is approximately 3.5 to 4.8%
• the Mn concentration in the residual ⁇ is approximately 1.40 to 2.5%
• (iii) ⁇ By controlling the L parameter within a range of approximately ⁇ 10 or less, toughness at ⁇ 233 ° C. can be improved.
• the toughness at ⁇ 233 ° C. is further improved. Can do.
• the thick steel plate of the present invention has been described above.
• the method for producing a thick steel plate according to the present invention as defined in claim 1 or 2 of the present invention is the temperature (L treatment temperature) in the heat treatment (L treatment) in the ⁇ - ⁇ 2 phase coexistence region (between A c1 and A c3 ).
• the L parameter calculated based on the following formula (5) composed of A c1 and A c3 in the steel is 0.25 or more and 0.45 or less, and the L parameter and the steel
• the manufacturing method of the present invention described above is for manufacturing a thick steel plate that satisfies the above requirements by appropriately controlling the rolling step and the subsequent tempering treatment (T treatment), and the steel making step is not particularly limited.
• the method used can be employed.
• the heating temperature is preferable to control the heating temperature to about 900 to 1100 ° C., the FRT (finish rolling temperature) to about 700 to 900 ° C., and the SCT (cooling start temperature) to about 650 to 800 ° C.
• the SCT is preferably controlled within the above-mentioned range within 60 seconds after finish rolling, whereby a microstructure useful for improving toughness can be obtained after rolling ⁇ cooling.
• the temperature range from 800 ° C. to 500 ° C. is cooled at an average cooling rate of about 10 ° C./s or more.
• the average cooling rate in the above temperature range is particularly controlled in order to obtain a fine structure after cooling.
• the upper limit is not particularly limited.
• the stop temperature at the above average cooling rate is preferably 200 ° C. or less.
• the L treatment temperature after hot rolling is preferably controlled within the range of A c1 to (A c1 + A c3 ) / 2.
• alloy elements such as Ni are concentrated in the generated ⁇ phase, and a part thereof becomes a metastable residual ⁇ phase that exists metastable at room temperature.
• the L treatment temperature is less than the A c1 point or more than [(A c1 + A c3 ) / 2]
• the residual ⁇ fraction at ⁇ 196 ° C. or the stability of the residual ⁇ cannot be secured sufficiently as a result (described later). (See Nos. 29 and 30 in Table 2B of Example 1).
• a preferable L treatment temperature is approximately 620 to 650 ° C.
• the Ac1 point and the Ac3 point are calculated based on the following formulas ("Lecture / Modern Metallurgy Materials 4 Steel Materials", Japan Institute of Metals).
• a c1 point 723-10.7 ⁇ [Mn] ⁇ 16.9 ⁇ [Ni] + 29.1 ⁇ [Si] + 16.9 ⁇ [Cr] + 290 ⁇ [As] + 6.38 ⁇ [W]
• a c3 point 910 ⁇ 203 ⁇ [C] 1/2 ⁇ 15.2 ⁇ [Ni] + 44.7 ⁇ [Si] + 104 ⁇ [V] + 31.5 ⁇ [Mo] + ⁇ 30 ⁇ [Mn] + 11 ⁇ [Cr] + 20 ⁇ [Cu]
• [] means the concentration (mass%) of the alloying element in the steel material.
• As and W are not included as components in the steel, and in the above formula, [As] and [W] are both calculated as 0%.
• the heating time (holding time) at the above two-phase region temperature is preferably about 10 to 50 minutes. If it is less than 10 minutes, the alloy element concentration to the ⁇ phase does not proceed sufficiently, whereas if it exceeds 50 minutes, the ⁇ phase is annealed and the strength decreases.
• the upper limit of the preferred heating time is 30 minutes.
• the L parameter represented by the above formula (5) is set to 0.25 or more and 0.45 or less for each component.
• the L parameter is a parameter set in order to efficiently use the alloy concentration during the L treatment in order to finally have both the volume fraction of the residual ⁇ and the stability of the residual ⁇ .
• the desired residual ⁇ fraction and / or the stability of the residual ⁇ cannot be sufficiently obtained.
• they are 0.28 or more and 0.42 or less, More preferably, they are 0.30 or more and 0.40 or less.
• the ⁇ L parameter determined by the respective contents of Mn, Cr and Mo and the L parameter is controlled to be 7 or less.
• This ⁇ L parameter is set to suppress the adverse effect of temper embrittlement that occurs in the concentrated part when P is segregated to the old ⁇ grain boundary during L treatment and Mn and Cr are excessively concentrated. It is. Since it is difficult to directly measure the amount of P segregated at the old ⁇ grain boundary, the ⁇ L parameter can be regarded as an alternative parameter for the amount of P segregated at the old ⁇ grain boundary. Those having a small segregation of P to the former ⁇ grain boundary have a small ⁇ L parameter.
• the lower limit is not particularly limited, but it is preferable to suppress the amount of addition of Mo as much as possible from the viewpoint of cost.
• the content and the preferable range of the L parameter approximately ⁇ 30 or more It is preferable that
• tempering T treatment
• the tempering process is performed at a temperature of Ac1 or lower for 10 to 60 minutes.
• C is concentrated in the metastable residual ⁇ and the stability of the metastable residual ⁇ phase is increased, so that a residual ⁇ phase that exists stably even at ⁇ 196 ° C. is obtained.
• a low Ms point can be secured by the low temperature tempering.
• the tempering temperature exceeds the Ac1 temperature
• the metastable residual ⁇ phase generated while maintaining the two-phase coexistence region is decomposed into an ⁇ phase and a cementite phase, and a sufficient residual ⁇ phase at ⁇ 196 ° C. cannot be secured.
• the tempering temperature is less than 540 ° C. or when the tempering time is less than 10 minutes
• C concentration into the metastable residual ⁇ phase does not proceed sufficiently, and the desired residual ⁇ at ⁇ 196 ° C. The amount cannot be secured.
• the tempering time exceeds 60 minutes, the dislocation density of the ⁇ phase is excessively reduced, and a predetermined strength (TS and YS) cannot be secured (No. 33 in Table 2B of Example 1 described later is set. reference).
• Preferred tempering conditions are tempering temperature: 540 to 560 ° C., tempering time: 15 minutes or more and 45 minutes or less (more preferably 35 minutes or less, more preferably 25 minutes or less).
• the cooling method after tempering is not water cooling but air cooling. This is because carbon concentrates in the residual ⁇ during air cooling, so that the residual ⁇ stabilization parameter is larger in air cooling than in water cooling.
• regulated to this-application Claim 3 is demonstrated.
• the L parameter calculated based on the formula (5) is 0.6 or more and 1.1 or less
• the step of adjusting the L treatment temperature and steel components so that the ⁇ L parameter calculated based on the equation is 0 or less, and the L treatment, followed by water cooling to room temperature and tempering treatment (T treatment) is characterized in that it is performed at a temperature of Ac 1 or lower for 10 to 60 minutes.
• the L parameter represented by the formula (5) is set to 0.6 or more and 1.1 or less.
• the L parameter is a parameter set to finally combine the volume fraction of residual ⁇ and the stability of residual ⁇ (particularly expressed by the Di value and the Mn concentration in the residual).
• the upper limit (1.1 or less) was specified from the viewpoint of the components of the thick steel plate and the desired structure conditions. Note that increasing the stability of the residual ⁇ by the L treatment (that is, concentrating Mn into the residual ⁇ ) means that the Mn concentration of the parent phase (in the steel) is diluted when reversed.
• the lower limit of L parameter (0.6 or more) is set in the present invention.
• a preferable L parameter is 0.7 or more and 1.0 or less.
• the contents of Mn, Cr and Mo in the steel and the ⁇ L parameter determined by the L parameter are controlled to be 0 or less.
• this ⁇ L parameter is used to suppress the adverse effect of temper embrittlement that occurs in the concentrated portion when P is segregated to the old ⁇ grain boundary during L treatment and Mn and Cr are excessively concentrated. It is set. Since the amount of P segregating at the old grain boundary cannot be directly measured, the ⁇ L parameter can be regarded as an alternative parameter for the amount of P segregating at the old ⁇ grain boundary. Those having a small segregation of P to the former ⁇ grain boundary have a small ⁇ L parameter. Preferably it is -10.0 or less.
• the lower limit is not particularly limited, but it is preferable to suppress the amount of addition of Mo as much as possible from the viewpoint of cost. In addition, generally considering the content and the preferable range of the L parameter, approximately ⁇ 30 or more It is preferable that
• tempering T treatment
• the tempering process is performed at a temperature of Ac1 or lower for 10 to 60 minutes. As described above, C is concentrated in the metastable residual ⁇ by such low temperature tempering, and the stability of the metastable residual ⁇ phase is increased. Therefore, a residual ⁇ phase that exists stably even at ⁇ 196 ° C. is obtained. Moreover, a low Ms point can be secured by the low temperature tempering.
• the tempering temperature exceeds A c1
• the metastable residual ⁇ phase generated while maintaining the two-phase coexistence region is decomposed into an ⁇ phase and a cementite phase, and a sufficient residual ⁇ phase at ⁇ 196 ° C. cannot be secured.
• the tempering time is less than 10 minutes, the C concentration in the metastable residual ⁇ phase does not proceed sufficiently, and the desired residual ⁇ amount at ⁇ 196 ° C. cannot be ensured.
• the tempering time exceeds 60 minutes, the dislocation density of the ⁇ phase is excessively reduced, and a predetermined strength (TS) cannot be secured (see No. 7 in Table 2B of Example 3 described later).
• a preferable tempering time is 15 minutes or more and 45 minutes or less, more preferably 20 minutes or more and 35 minutes or less.
• the tempering temperature is a temperature of A c1 or less, and the preferable tempering temperature is 510 ° C. to 520 ° C.
• the cooling method after tempering is not water cooling but air cooling. This is because carbon is concentrated in the residual ⁇ during air cooling, so that the stability of the residual ⁇ is higher in air cooling than in water cooling.
• Example 1 Example relating to a thick steel plate satisfying a brittle fracture surface ratio ⁇ 10% at ⁇ 196 ° C., a tensile strength TS> 741 MPa, and a yield strength YS> 590 MPa.
• a test steel having a component composition (remainder: iron and inevitable impurities, the unit is mass%) was melted and cast, and then a 150 mm ⁇ 150 mm ⁇ 600 mm ingot was produced by hot forging.
• misch metal containing about 50% Ce and about 25% La was used as REM.
• the finish rolling temperature is 700 ° C.
• SCT within 60 seconds after FRT is 650 ° C.
• the average cooling rate from 800 to 500 ° C. was 19 ° C./s, and cold rolling was performed to a stop temperature of 200 ° C. or lower.
• the steel plate thus obtained was subjected to L treatment at the L treatment temperature shown in Table 2, and heated and held for 30 minutes, and then cooled with water. Further, T treatment (tempering) was performed at the temperature (T treatment temperature) and time (T time) shown in Table 2, and then cooled to room temperature.
• the amount of residual ⁇ phase (volume fraction) present at ⁇ 196 ° C., the residual ⁇ stabilization parameter, tensile properties (tensile strength TS, yield strength YS) are as follows. ), And cryogenic toughness (the brittle fracture surface ratio in the C direction at ⁇ 196 ° C. or ⁇ 233 ° C.).
• the peaks of the lattice planes (110), (200), (211), and (220) of the ferrite phase and the lattices of (111), (200), (220), and (311) of the residual ⁇ phase For the peak of the surface, based on the integrated intensity ratio of each peak, calculate the volume fraction of (111), (200), (220), (311) of the residual ⁇ phase, and obtain the average value of these, Was defined as “volume fraction of residual ⁇ ”.
• each of the residual ⁇ existing at ⁇ 196 ° C. constituting the above equation (2) Components, that is, C content ⁇ C>, Mn content ⁇ Mn>, Al content ⁇ Al>, Cu content ⁇ Cu>, Ni content ⁇ Ni>, Cr content ⁇ Cr>, Mo content ⁇ Mo>, V content ⁇ V > was measured as follows.
• Ni concentration during each heat treatment of L treatment and T treatment is expressed by the following equation. (Constant during each heat treatment) x (Driving force of ⁇ reverse transformation) x (Diffusion coefficient of each alloy element)
• (driving force of ⁇ reverse transformation) in the above formula was calculated by commercially available calculation software (thermocalc) based on the temperature during each heat treatment.
• the (diffusion coefficient of each alloy element) in the above formula was calculated based on the temperature and holding time during each heat treatment using the value of “DiffusionDin Solid Metals and Alloys” (H. Mehrer, 1990).
• the measured Ni concentration after L treatment ⁇ T treatment is ⁇ (constant during L treatment) ⁇ (driving force of ⁇ reverse transformation) ⁇ (diffusion coefficient of Ni during L treatment) ⁇ ⁇ (Constant at the time of T treatment) ⁇ (driving force for ⁇ reverse transformation) ⁇ (diffusion coefficient of Ni at the time of L treatment) ⁇ . That is, the measured Ni concentration after L treatment ⁇ T treatment includes both (constant for L treatment) and (constant for T treatment), and (constant for T treatment) is (constant for L treatment).
• cryogenic toughness brittle fracture surface ratio in the C direction
• t / 4 position t: plate thickness
• W / 4 position W: plate width
• t / 4 position and W of each steel plate / 3 position three Charpy impact test pieces (V-notch test piece of JIS Z 2242) were taken in parallel with the C direction, and the brittle fracture surface rate at -196 ° C (%) was measured by the method described in JIS Z2242. Were measured and the average value of each was calculated. Of the two average values calculated in this way, the average value that is inferior in characteristics (that is, the brittle fracture surface ratio is large) is adopted, and this value is 10% or less. Then, it evaluated that it was excellent in cryogenic toughness.
• Examples 1 to 25 are examples that satisfy all of the requirements of the present invention. Even if the base metal strength is high, the cryogenic toughness at ⁇ 196 ° C. (specifically, the average value of the brittle fracture surface ratio in the C direction ⁇ 10 %), An excellent thick steel plate could be provided.
• No. in Table 2B. Nos. 26 to 45 are comparative examples that do not satisfy the requirements of the present invention because they do not satisfy any of the components in the steel and the preferred production conditions of the present invention, and the desired characteristics cannot be obtained.
• No. No. 26 is an example in which the Di value does not satisfy the requirements of the present invention, and the desired volume fraction of residual ⁇ cannot be obtained, and the residual ⁇ stabilization parameter also decreases. Furthermore, the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter also exceeded the predetermined range. As a result, the brittle fracture surface ratio also increased and the desired cryogenic toughness could not be realized at -196 ° C. Moreover, since Di value was low, TS also fell.
• No. No. 28 is No. in Table 1B with a large amount of P.
• the desired volume fraction of residual ⁇ was not obtained, and the residual ⁇ stabilization parameter was also reduced.
• the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter also exceeded the predetermined range. As a result, the cryogenic toughness decreased.
• No. No. 30 is No. in Table 1B with a large amount of Si. 30 and heating at a temperature exceeding the two-phase region temperature (L treatment temperature), and the L parameter and the ⁇ L parameter are high. Therefore, the amount of residual ⁇ was insufficient and the residual ⁇ stabilization parameter was also reduced. Furthermore, the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter also exceeded the predetermined range. As a result, the cryogenic toughness decreased.
• No. No. 32 is No. in Table 1B with a large amount of Mn. 32, and the ⁇ L parameter is high. As a result, the cryogenic toughness decreased.
• No. No. 34 in Table 1B has a small amount of Mn and a small Di value.
• the desired volume fraction of residual ⁇ was not obtained, and the residual ⁇ stabilization parameter was also reduced.
• the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter also exceeded the predetermined range.
• the brittle fracture surface ratio also increased and the desired cryogenic toughness could not be realized at -196 ° C.
• TS also fell.
• No. No. 37 in Table 1B has a small amount of C, a large amount of Al, and a small amount of Ni. Since 37 was used, the amount of residual ⁇ was insufficient and the residual ⁇ stabilization parameter was also reduced. Furthermore, the volume fraction of residual ⁇ and the residual ⁇ stabilization parameter also exceeded the predetermined range. As a result, the cryogenic toughness decreased. TS also decreased.
• No. No. 38 in Table 1B has a small amount of Al and a large amount of N. Since 38 was used, the cryogenic toughness decreased.
• No. No. 42 in Table 1B has a large amount of Mo as a selection component and a large Di value. Since 42 was used, the cryogenic toughness decreased.
• Example 2 In this example, the brittle fracture surface rate at ⁇ 233 ° C. was evaluated for some of the data used in Example 1 (all of the examples of the present invention).
• the brittle fracture surface ratio ⁇ 50% was evaluated as being excellent in the brittle fracture surface ratio at ⁇ 233 ° C.
• Example 3 Example relating to a thick steel plate satisfying a brittle fracture surface ratio ⁇ 10% at ⁇ 196 ° C., a tensile strength TS> 830 MPa, and a yield strength YS> 690 MPa.
• a test steel having a component composition (remainder: iron and inevitable impurities, the unit is mass%) was melted and cast, and then a 150 mm ⁇ 150 mm ⁇ 600 mm ingot was produced by hot forging.
• misch metal containing about 50% Ce and about 25% La was used as REM.
• the finish rolling temperature is 700 ° C.
• SCT within 60 seconds after FRT is 650 ° C.
• the average cooling rate from 800 to 500 ° C. was 19 ° C./s, and cold rolling was performed to a stop temperature of 200 ° C. or lower.
• the steel plate thus obtained was subjected to L treatment at the L treatment temperature shown in Table 5, heated and held for 30 minutes, and then cooled with water. Further, T treatment (tempering) was performed at the temperature (T treatment temperature) and time (T time) shown in Table 2, and then cooled to room temperature.
• the amount of residual ⁇ phase (volume fraction) present at ⁇ 196 ° C., the amount of Mn in the residual ⁇ phase, tensile properties (tensile strength TS, yield strength YS), cryogenic temperature Toughness (the brittle fracture surface ratio in the C direction at -196 ° C or -233 ° C) was evaluated.
• the average amount of Mn in the residual ⁇ phase was measured with TEM-EDX and calculated according to the following procedure. In the calculation, it was assumed that the component in the residual ⁇ phase was Fe—Mn—Ni. Actual components may include, for example, C, Si and the like in addition to Fe, Mn, and Ni, but these elements are in a small amount and can be substantially ignored in this embodiment.
• a 10 mm ⁇ 10 mm ⁇ 55 mm test piece was taken from the t / 4 position of each steel plate, held at a liquid nitrogen temperature ( ⁇ 196 ° C.) for 5 minutes, and then the test piece was made into a size of 10 mm ⁇ 10 mm ⁇ 2 mm. After cutting and mechanically polishing the thickness t from 2 mm to 0.1 mm, it was punched out to a size of 3 mm ⁇ to prepare a thin film sample by electrolytic polishing.
• the thin film sample thus obtained was identified with a transmission image and a reciprocal lattice using a transmission electron microscope H-800 manufactured by Hitachi, Ltd., and then the above-mentioned ⁇ was detected using an EDX analyzer EMAX7000 manufactured by Horiba.
• the Mn concentration in the phase was measured.
• Measurement by EDX was performed under the conditions of an acceleration voltage of 200 kV and an observation magnification of 75000 times, and each sample was measured at five points, and the average value was taken as the amount of Mn in the residual ⁇ .
• Example 3 unlike Example 1, TS> 830 MPa and YS> 690 MPa were evaluated as having excellent base material strength.
• No. in Table 5A Nos. 1 to 21 are No. 1 in Table 4A in which the components in the steel satisfy the requirements of the present invention.
• 1 to 21 is an example prepared under the production conditions of the present invention, and the cryogenic toughness at ⁇ 196 ° C. (specifically, the average value of the brittle fracture surface ratio in the C direction) even if the base metal strength is high It was possible to provide a thick steel plate excellent in ⁇ 10%.
• No. in Table 5B. Nos. 1 to 21 are comparative examples not satisfying any of the components in the steel and the production conditions of the present invention, and the desired characteristics were not obtained.
• No. in Table 5B No. 10 in Table 4B has a small amount of C, a large amount of Al, a small amount of Ni, and the Ni—Mn balance of the above formula (2) is below the preferred range. 10 is an example. Since the amount of C and Ni useful for securing the amount of residual ⁇ is small, the volume ratio of residual ⁇ is small. As a result, the cryogenic toughness decreased and YS was good. However, since the amount of C and Ni effective for strength improvement are small, TS decreased.
• Table 5BNo. 11 has less amount of Al and Mo content, the number is N quantity, lambda L parameter is high Table 4B No. Since 11 was used, the cryogenic toughness decreased.
• No. 21 in Table 4B has a small Mo amount and a high L parameter and a high ⁇ L parameter. 21 is an example. As a result, the brittle fracture surface ratio also increased and the desired cryogenic toughness could not be realized at -196 ° C.
• Example 4 In this example, the brittle fracture surface rate at ⁇ 233 ° C. was evaluated for the inventive examples of Table 5A used in Example 3 above.
• No. 1 described in Table 6 was obtained. (No. in Table 6 corresponds to Nos. In Table 4A and Table 5A described above) Three test pieces were collected from the t / 4 position and the W / 4 position, and -233 was obtained by the method described below. A Charpy impact test at °C was conducted to evaluate the average brittle fracture surface ratio. In this example, the brittle fracture surface ratio ⁇ 50% was evaluated as being excellent in the brittle fracture surface ratio at ⁇ 233 ° C. "High pressure gas", Vol. 24, page 181, "Cryogenic impact test of austenitic cast stainless steel"
• No. in Table 6 Nos. 1 to 3, 5 to 14, and 17 to 20 are all No. 1 in Table 5A that satisfy at least one of the above (i) to (iii). Examples 1 to 3, 5 to 14, and 17 to 20 were used, and the brittle fracture surface ratio at ⁇ 233 ° C. was good at 50% or less.
• no. Nos. 4, 15, 16, and 21 satisfy No. 1 in Table 5A that do not satisfy any of the requirements (i) to (iii) above. In this example, 4, 15, 16, and 21 were used, and the desired toughness could not be obtained at -233 ° C.
• No. in Table 6 No. 21 in Table 5A does not have any of the requirements (i) to (iii) above. Since No. 21 was used, the desired toughness could not be obtained at -233 ° C.
• the steel plate of the present invention is useful as a steel plate that comes into contact with a cryogenic substance, such as a storage tank for liquefied natural gas.

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• 2013
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  • 2013-12-11 KR KR1020157015524A patent/KR101711774B1/ko active IP Right Grant
  • 2013-12-11 EP EP17000237.2A patent/EP3190201A1/en not_active Withdrawn
  • 2013-12-11 EP EP13861920.0A patent/EP2933347A4/en not_active Withdrawn
  • 2013-12-11 WO PCT/JP2013/083239 patent/WO2014092129A1/ja active Application Filing

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