CN108368579A - The steel plate of pole excellent in low temperature toughness - Google Patents
The steel plate of pole excellent in low temperature toughness Download PDFInfo
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- CN108368579A CN108368579A CN201680073537.8A CN201680073537A CN108368579A CN 108368579 A CN108368579 A CN 108368579A CN 201680073537 A CN201680073537 A CN 201680073537A CN 108368579 A CN108368579 A CN 108368579A
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- 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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- 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
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- 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
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- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- 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
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- 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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
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Abstract
A kind of steel plate of pole excellent in low temperature toughness is provided, it is the steel plate that Ni contents are 5.50~7.50%, its meet as defined at being grouped as, and the volume fraction v of existing retained austenite phase is 4.0~12% at -196 DEG C, and, if plate thickness is t, the section elements shown in following formula (1) constitute parameter M values and meet 2.4 or more.In following formula (1), DI is by following formula (2) calculated value, and [] indicates the content of each element in terms of quality %.M values=(DI × v2)/t ... (1) DI=1.16 × ([C]/10)0.5×(0.7×[Si]+1)×(1+3.33×[Mn])×(1+0.35×[Cu])×(1+0.36×[Ni])×(1+2.16×[Cr])×(1+3×[Mo])×(1+1.75×[V])×1…(2)
Description
Technical field
The present invention relates to steel plates, are to be related to even if Ni contents being 5.50~7.5%, -196 DEG C of pole in detail
The toughness toughness of plate width direction (directions C) [especially] under low temperature also good steel plate.Hereinafter, to expose to the open air in above-mentioned pole
Under low temperature towards liquefied natural gas (Liquefied Natural Gas；LNG it is illustrated centered on steel plate), but this
The steel plate of invention is not limited to this, but can be comprehensively suitable for exposing this kind of purposes under -196 DEG C of extremely low temperature to the open air
Steel plate.
Background technology
The LNG container steel plates of storage tank for liquefied natural gas (LNG) also require to have other than high intensity
The high tenacity of tolerable -196 DEG C of extremely low temperature.Up to now, as the steel plate for such use, use containing
The steel plate (9%Ni steel) that Ni is 9% or so.But in recent years, because of the cost increase of Ni, for Ni contents are reduced
To being less than 9%, the exploitation of the still excellent steel plate of pole low-temperature flexibility is promoting.
For example, in non-patent literature 1, describe about α-γ two-phase coexistents area (Ac1Point~Ac3Between point) heat treatment
(sometimes referred to as L processing.) bring 6%Ni steel low-temperature flexibility influence.In detail, it describes just like inferior content：It is being tempered
Before processing, by applying the heat treatment of α-γ two-phase coexistents areas, it can be assigned and handled by common Q-tempering
The pole low-temperature flexibility at -196 DEG C more than 9%Ni steel is same；The heat treatment also makes the test film in the directions C (plate width direction)
Toughness improves；These effects are based on retained austenite that is a large amount of fine and also stablizing for the shock loading under extremely low temperature
Existing situation.But the test film described in above-mentioned non-patent literature 1, although the pole low-temperature flexibility of the directions L (rolling direction) is excellent
It is different, but the pole low-temperature flexibility of the directions C (plate width direction) has the tendency that than L direction difference.
Technology same as above-mentioned non-patent literature 1, is disclosed in patent document 1 and patent document 2.Wherein in patent text
Being described in offering 1 has a kind of method, is for containing 4.0~10% Ni, austenitic grain size etc. controls the steel in prescribed limit
After carrying out hot rolling, it is heated to Ac1Point~Ac3(it is equivalent to the L processing described in above-mentioned non-patent literature 1) between point, then carries out cold
But, it is above processing be repeated 1 times or 2 times or more after, with Ac1The method that point temperature below is tempered.In addition in patent document
Described in 2, for containing 4.0~10% Ni, and the size of the AlN before hot rolling made to be in 1 μm of steel below, carry out with
The similarly heat treatment (L processing → temper) of above patent document 1.The impact value at -196 DEG C is described in these documents
(vE- 196), but impact value supposition is the directions L, the impact value in the directions C is unclear.
In addition, in non-patent literature 2, describe about by above-mentioned L processing (heat treatment of two-phase coexistent area) and TMCP
The exploitation for the LNG container 6%Ni steel that (Thermo-Mechanical Control Process) is combined.It is non-specially at this
It is described in sharp document 2, the toughness of the directions L (rolling direction) shows high value.
In addition, in patent document 3, the thick steel plate for low temperature use for having a kind of section Ni types is described, it is below low at -165 DEG C
It is similarly excellent with the Resisting fractre safety of 9%Ni steel under warm environment.The thick steel plate for low temperature use, containing higher than 5.0%, be less than
8.0% Ni, the yield strength under room temperature are 590MPa or more.Described in the patent document 3, the steel ingot for heating into
In capable roughing, 3~8 times that the ingot thickness at the end of roughing reaches products thickness are depressed to, the toughness of steel plate is thus made
It improves.In addition, describing in embodiment, using the test film extracted from rolling right angle orientation, the stretching examination at -165 DEG C is carried out
It tests, measures tensile strength TS and yield strength YS, and the Charpy impact of the unit area of Measure section absorbs energy vE- 196.It should
Charpy impact absorbs can vE- 196Average value as 3 test films acquires.
In addition, being described in non-patent literature 3, if for containing Ni：5~11% or so steel is implemented at two phase region heat
Reason, becomes the tissue for making to be dispersed with stable retained austenite in tempered martensite on a small quantity, then transition temperature is greatly reduced, even if
Excellent toughness is also showed that in low temperature.It is described this is because, austenite is generated along lath boundaries, to disconnected as cleavage
The lath block and lath beam of mouth unit are cut off and miniaturization.
As more than, up to now, needle improves the technology of low-temperature flexibility in Ni contents for 4.0~11% or so Ni steel
It is proposed has several.But in the above documents, there is no the toughness under fully -196 DEG C of temperature extremely low in this way of research, especially C
The pole low-temperature flexibility in direction.In detail, it is 690~830MPa in the tensile strength TS of base material, yield strength YS is 590MPa
In above high-strength steel plate, the technology for improving the pole low-temperature flexibility in the directions C is not studied.
In addition, in the above documents, not discussing for percentage of brittle fracture surface.So-called percentage of brittle fracture surface is to indicate
The area occupation ratio of the brittleness section occurred when applying load in pendulum impact test.At the position that brittle fracture occurs, steel are inhaled
The energy of receipts significantly becomes smaller until reach fracture, is easy that fracture is made to carry out, therefore in pole low-temperature flexibility develops skill, make-
Percentage of brittle fracture surface at 196 DEG C is 10% or less and particularly important important document.
The applicant in patent document 4, proposes in the Ni steel that Ni contents are 5.0~7.5% or so, at -196 DEG C
The pole low-temperature flexibility pole low-temperature flexibility of the directions C (especially) it is excellent, percentage of brittle fracture surface is inhibited in 10% high intensity below
Steel plate.The steel plate has the feature that, is present in containing for Mn system field trash of in the steel, maximum gauge higher than 0.1 μm
Amount be 0.001 to 0.07 quality %, also, at -196 DEG C existing retained austenite phase divide rate be 2.0~12.0 bodies
Product %.
【Look-ahead technique document Prior Art】
【Patent document】
【Patent document 1】Japanese Unexamined Patent Application 49-135813 bulletins
【Patent document 2】Japanese Unexamined Patent Application 51-13308 bulletins
【Patent document 3】Japanese Unexamined Patent Publication 2011-241419 bulletins
【Patent document 4】Japanese Unexamined Patent Publication 2014-210948 bulletins
【Non-patent literature】
【Non-patent literature 1】Arrow is wild clear to be helped, and " heat treatment of α-γ two-phase coexistents area brings the low-temperature flexibility of 6%Ni steel
Influence ", iron and steel, the 59th year (1973) No. 6, p752~763
【Non-patent literature 2】Gu Gu, " exploitation of LNG containers 6%Ni steel ", CAMP-ISIJ, Vol.23 (2010),
p1322
【Non-patent literature 3】Positive will is herded, " Strengthening and Toughening of nearest steel ", Japanese metal Society report, volume 27, No. 8
(1988)
In the above patent document 4 that the applicant is previously proposed, according to the percentage of brittle fracture surface at -196 DEG C, evaluation -
Pole low-temperature flexibility (the especially pole low-temperature flexibility in the directions C) at 196 DEG C.But the knot that inventors further study repeatedly
Fruit is distinguished, in order to further increase the pole low-temperature flexibility at -196 DEG C, the percentage of brittle fracture surface at by -196 DEG C inhibits
After 10% or less, it is also necessary to can obtain stable toughness when carrying out general pendulum impact test at -196 DEG C.That is,
It is not to enable the average value of absorption, but make it most when carrying out at -196 DEG C pendulum impact test using multiple test films
Low value is 150J or more.
Invention content
The present invention is done in view of the foregoing, it is intended that providing a kind of pole excellent in low temperature toughness in the especially directions C
Steel plate, in the Ni steel that Ni contents are 5.50~7.5%, with tensile strength for 690~830MPa, yield strength is
590MPa or more, when carrying out pendulum impact test at -196 DEG C, percentage of brittle fracture surface is 10% or less as premise, absorption energy
Minimum meet 150J or more.
The steel plate that can solve the so-called pole excellent in low temperature toughness of the present invention of the above subject, is contained in terms of quality %
There is C：0.04~0.09%, Si：Higher than 0% and below 0.30%, Mn：0.50~1.10%, P：Higher than 0% and
0.004% or less, S：Higher than 0% and less than 0.0030%, Al：0.010~0.040%, Ni：5.50~7.5%, Cr：0.30
~0.6%, Mo：Higher than 0% and below 0.20% and N：Higher than 0% and 0.0055% hereinafter, surplus is by iron and can not keep away
The steel plate that the impurity exempted from is constituted.Moreover, having main idea in the following areas：The existing retained austenite phase at -196 DEG C
Volume fraction v is 4.0~12%, also, when setting the plate thickness of the steel plate as t, and section elements shown in following formula (1), which are constituted, joins
Number M values meet 2.4 or more.In following formula (1), DI is by following formula (2) calculated value, and [] indicates each member in terms of quality %
The content of element.
M values=(DI × v2)/t…(1)
DI=1.16 × ([C]/10)0.5×(0.7×[Si]+1)×(1+3.33×[Mn])×(1+0.35×[Cu])×
(1+0.36×[Ni])×(1+2.16×[Cr])×(1+3×[Mo])×(1+1.75×[V])×1…(2)
Above-mentioned steel plate in terms of quality %, can also also contain the group constituted from following element as other elements
At least one of middle selection：
(a)Cu：Higher than 0% and 0.3% hereinafter, and/or
(b)Nb：Higher than 0% and 0.03% hereinafter, Ti：Higher than 0% and 0.025% hereinafter, and V：Higher than 0% and
0.03% or less.
In the present invention, make the volume fraction v of existing retained austenite (γ) phase at -196 DEG C for defined range and
Be controlled and then suitably adjust according to steel plate at be grouped as calculated DI, above-mentioned volume fraction v and based on thickness
The calculated section elements of plate thickness t of steel plate constitute parameter M values.Therefore, it is 690~830MPa meeting tensile strength, bends
It is 590MPa or more to take intensity, when carrying out pendulum impact test at -196 DEG C, after percentage of brittle fracture surface meets 10% or less,
It is 150J or more that can also enable the minimum of absorption.The pole excellent in low temperature toughness in the steel plate especially directions C.
Description of the drawings
Fig. 1 is to indicate that section elements constitute the diagram of parameter M values and the relationship of percentage of brittle fracture surface.
Specific implementation mode
Inventors, after the technology for proposing above patent document 4, in order on the basis of ensuring high intensity, further
The pole low-temperature flexibility in the directions C at -196 DEG C of improvement, and sharp study repeatedly.Itself as a result, it has been found that, in order to make high intensity and-
The pole low-temperature flexibility in the directions C at 196 DEG C is existed side by side, same as above patent document 4, it is important that is made existing at -196 DEG C
The volume fraction v of retained austenite phase be 4.0~12%, in addition, again by according to steel plate at be grouped as calculated DI, on
It states the calculated section elements of volume fraction v and plate thickness t based on steel plate and constitutes the control of parameter M values 2.4 or more,
Steel plate so as to complete the present invention.Constitute parameter M values especially by above-mentioned section elements are appropriately controlled, can inhibit make it is tough
Property deterioration section elements coarsening, therefore can realize very excellent pole low-temperature flexibility.
" pole excellent in low temperature toughness " so-called in this specification is meant through the method described in one column of aftermentioned embodiment,
When carrying out the pendulum impact test of the directions C (plate width direction) at -196 DEG C, meet percentage of brittle fracture surface for 10% hereinafter, and inhaling
The minimum for receiving energy meets 150J or more.In the later-described embodiments, the Charpy impact without the directions L (rolling direction) tries
It tests, but considers from the rule of thumb, it is believed that if the toughness in the directions C is good, the toughness in the directions L is also inevitable good.
So-called in the present specification " steel plate " means thickness generally 6~50mm of steel plate.
Hereinafter, the steel plate for embodiments of the present invention illustrates into ground.
It is illustrated firstly, for the steel plate of embodiments of the present invention at being grouped as.
The steel plate of embodiments of the present invention contains C as basis in terms of quality %：0.04~0.09%,
Si：Higher than 0% and below 0.30%, Mn：0.50~1.10%, P：Higher than 0% and below 0.004%, S：Simultaneously higher than 0%
Less than 0.0030%, Al：0.010~0.040%, Ni：5.50~7.5%, Cr：0.30~0.6%, Mo：Higher than 0% and
0.20% or less and N：Higher than 0% and below 0.0055%.In addition, hereinafter, % means quality %.
C is to improve intensity, and the required element of residual γ amounts being for ensuring that at -196 DEG C is used in combination.C amounts are less than
When 0.04%, intensity is insufficient.In addition, cannot ensure to remain γ amounts at -196 DEG C, therefore pole low-temperature flexibility cannot be improved.Cause
This in embodiments of the present invention, C amounts be 0.04% or more.C amounts be preferably 0.045% or more, more preferably 0.05% with
On.But if C amounts are higher than 0.09%, intensity becomes excessively high, and pole low-temperature flexibility deteriorates instead.Therefore in the implementation of the present invention
In mode, C amounts are 0.09% or less.C amounts are preferably 0.08% hereinafter, more preferably 0.07% or less.
Si is the element to work as deoxidation material.In order to effectively play such effect, Si amounts are preferably 0.01%
More than.Si amounts are more preferably 0.03% or more, further preferably 0.05% or more.But if excessively containing Si, hard
The generation of island-like martensite phase be promoted, pole low-temperature flexibility cannot be improved.Therefore in embodiments of the present invention, Si amounts are
0.30% or less.Si amounts are preferably 0.25% hereinafter, more preferably 0.20% or less.
Mn is to make the stabilized elements of γ, the required element of residual γ amounts being for ensuring that at -196 DEG C.From this
Viewpoint is set out, and in embodiments of the present invention, Mn amounts are 0.50% or more.Mn amounts are preferably 0.60% or more, more preferably
0.70% or more.But if excessively containing Mn, temper embrittlement is brought, therefore pole low-temperature flexibility cannot be improved.Therefore at this
In the embodiment of invention, Mn amounts are 1.10% or less.Mn amounts are preferably 1.05% hereinafter, more preferably 1.00% or less.
P is the impurity element as embrittlement of grain boundaries reason, cannot improve pole low-temperature flexibility.Therefore in the embodiment party of the present invention
In formula, P amounts are 0.004% or less.P amounts are preferably 0.003% hereinafter, more preferably 0.002% or less.The fewer P amounts the better, but
Industrially it is difficult to that P amounts is made to reach 0%.
S and above-mentioned P are again it is impurity element as embrittlement of grain boundaries reason.If excessively containing S, percentage of brittle fracture surface
It gets higher, pole low-temperature flexibility cannot be improved.Therefore in embodiments of the present invention, S amounts are less than 0.0030%.S amounts are preferably
0.0025% hereinafter, more preferably 0.0020% or less.The fewer S amounts the better, but industrially is difficult to that S amounts is made to reach 0%.
Al is the element to work as deoxidier, if Al amounts are very few, the oxygen concentration in steel rises, coarse Al systems folder
The amount of sundries increases, and cannot improve pole low-temperature flexibility.Therefore in embodiments of the present invention, Al amounts are 0.010% or more.Al
Amount preferably 0.015% or more, more preferably 0.020% or more.If but Al amounts are superfluous, the island of hard same as Si
The generation of martensitic phase is promoted, and cannot improve pole low-temperature flexibility.Therefore in embodiments of the present invention, Al amounts are
0.040% or less.Al amounts are preferably 0.035% hereinafter, more preferably 0.030% or less.
Ni ensures the residual γ amounts at -196 DEG C, is to improve the required element of pole low-temperature flexibility.Therefore the present invention's
In embodiment, Ni amounts are 5.50% or more.Ni amounts are preferably 6.00% or more, more preferably 6.50% or more.It is preferred that
Contain Ni as much as possible, if but excessively contain Ni, cost increase.Therefore in embodiments of the present invention, Ni amounts are
7.5% or less.Ni amounts are preferably 7.4% hereinafter, more preferably 7.3% or less.
Cr is to improve hardenability, for ensuring the required element of intensity.In order to play such effect, the present invention's
In embodiment, Cr amounts are 0.30% or more.Cr amounts are preferably 0.35% or more, more preferably 0.40% or more.If but mistake
Contain Cr surplusly, then intensity becomes excessively high, and pole low-temperature flexibility deteriorates instead.Therefore in embodiments of the present invention, Cr amounts are
0.6% or less.Cr amounts are preferably 0.55% hereinafter, more preferably 0.50% or less.
Mo is the element for improving intensity, and pole low-temperature flexibility being made to improve.In order to effectively play such effect, Mo amounts are excellent
It is selected as 0.01% or more.Mo amounts are more preferably 0.02% or more, further preferably 0.03% or more.But if excessively contain
There is Mo, then intensity becomes excessively high, and pole low-temperature flexibility deteriorates instead.Therefore in embodiments of the present invention, Mo amounts are 0.20%
Below.Mo amounts are preferably 0.18% hereinafter, further preferably 0.16% or less.
N is the element for reducing pole low-temperature flexibility under strain-aging effect.Therefore in embodiments of the present invention, N
Amount is 0.0055% or less.N amounts are preferably 0.0050% hereinafter, more preferably 0.0045% or less.The fewer N amounts the better, but work
Make N amounts reach 0% in industry to have any problem.
The steel plate of embodiments of the present invention contains mentioned component as basis, and surplus is iron and inevitably
Impurity.So-called inevitable impurity is with raw material as ore, waste material etc. with meaning industrialization when manufacturing steel plate
Represent, due to manufacturing process it is various will thus mixed ingredient, quilt in the range of will not cause harmful effect to the present invention
Allow.
In embodiments of the present invention, for the purpose of further assigning characteristic, selection component below can be contained
(at least one of (a) and (b)).
(a)Cu：Higher than 0% and below 0.3%.
(b) from Nb：Higher than 0% and below 0.03%, Ti：Higher than 0% and below 0.025% and V：Simultaneously higher than 0%
At least one selected in the group constituted below 0.03%.
(a) Cu is to make the stabilized elements of γ, helps to ensure the residual γ amounts at -196 DEG C.In order to effectively play
Such effect, Cu amounts are preferably 0.001% or more.Cu amounts are more preferably 0.002% or more, further preferably 0.010%
More than.But if excessively containing Cu, intensity becomes excessively high, pole low-temperature flexibility deteriorates instead.Therefore in the implementation of the present invention
In mode, Cu amounts are preferably 0.3% or less.Cu amounts are more preferably 0.25% hereinafter, further preferably 0.10% or less.
(b) Nb, Ti and V are used as Carbonitride Precipitation, are the elements for improving intensity.Nb, Ti and V can individually contain,
It can also contain two or more.
In order to effectively play above-mentioned effect, Nb amounts are preferably 0.001% or more, more preferably 0.003% or more, into one
Step preferably 0.005% or more.Ti amounts are preferably 0.0001% or more, more preferably 0.0005% or more, further preferably
0.0010% or more.V amounts are preferably 0.0001% or more, more preferably 0.0005% or more, further preferably 0.0010%
More than.
But if excessively containing above-mentioned element, intensity becomes excessively high, and pole low-temperature flexibility deteriorates instead.Therefore at this
In the embodiment of invention, Nb amounts are preferably 0.025% hereinafter, more preferably 0.02% hereinafter, further preferably 0.01%
Below.Ti amounts are preferably 0.02% hereinafter, more preferably 0.01% hereinafter, further preferably 0.005% or less.V amounts are preferred
For 0.025% hereinafter, more preferably 0.02% hereinafter, further preferably 0.01% or less.
More than, the steel plate of embodiments of the present invention is illustrated at being grouped as.
The steel plate of embodiments of the present invention needs to meet the volume fraction v of the existing residual γ phases at -196 DEG C
It is 4.0~12%.Existing residual γ, contributes to the raising of pole low-temperature flexibility at -196 DEG C.In order to play such work
With in embodiments of the present invention, the volume fraction for keeping the residual γ phases at -196 DEG C shared in metal structure entirety is
4.0% or more.Above-mentioned volume fraction is preferably 6.0% or more, and more preferably 7.0% or more.But residual γ compares martensite
Phase (parent phase) is soft, if therefore residual γ amounts excessively, yield strength YS is lower.Therefore in embodiments of the present invention
In, the volume fraction for keeping the residual γ phases at -196 DEG C shared in metal structure totality is 12% or less.Above-mentioned volume fraction
Preferably 10.0% hereinafter, more preferably 9.0% or less.
In addition, the metal structure of the steel plate of embodiments of the present invention, it is important that the existing residual at -196 DEG C
The volume fraction v of γ phases, and remain the tissue other than γ and be not particularly limited, as long as usually existing tissue in steel plate
.
As the tissue other than residual γ, for example, the carbide etc. of bainite, martensite, cementite etc. can be enumerated.
The steel plate of embodiments of the present invention, residual γ phases at -196 DEG C body shared in metal structure entirety
Integration rate v is after meeting above range, based on volume fraction v, the plate thickness t (mm) of steel plate, according to the ingredient of steel plate
Calculated DI is formed, constituting parameter M values by following formula (1) calculated section elements also needs to meet 2.4 or more.
M values=(DI × v2)/t…(1)
In above formula (1), DI is by following formula (2) calculated value, and [] indicates the content of each element in terms of quality %.
DI=1.16 × ([C]/10)0.5×(0.7×[Si]+1)×(1+3.33×[Mn])×(1+0.35×[Cu])×
(1+0.36×[Ni])×(1+2.16×[Cr])×(1+3×[Mo])×(1+1.75×[V])×1…(2)
If above-mentioned section elements, which constitute parameter M values, is less than 2.4, the percentage of brittle fracture surface at -196 DEG C cannot be inhibited
10% or less.That is, in order to which one side ensures that tensile strength is the high intensity of 690~830MPa, the brittleness at -196 DEG C is broken on one side
Face rate inhibition improves pole low-temperature flexibility below 10%, needs to make section elements miniaturization.Lath block as section elements
It with lath beam, is cut off and miniaturization by the austenite generated along lath boundaries, this describes as the prior art and was enumerating
Among non-patent literature 3 etc..But in the method for being allowed to cut off by austenite, if the lath block diameter of base material tissue is coarse,
Then the generation point of austenite is reduced, and the Ovshinsky scale of construction that when tow-phase region heat treatment generates tails off, and section elements become thick, therefore difficult
To ensure desired toughness.
Lath block diameter is also related to DI, if DI becomes larger, lath block diameter becomes smaller.Therefore, in the embodiment party of the present invention
It is found in formula, if according to the volume fraction of the retained austenite phase at -196 DEG C, the relationship with plate thickness is adjusted based on steel
At the DI for being grouped as calculating, then lath block diameter can be controlled.
Above-mentioned M values are preferably 2.6 or more, more preferably 2.8 or more, further preferably 3.0 or more.M values are based on steel
At be grouped as, the volume fraction v of residual γ phases at -196 DEG C and the plate thickness t of steel plate are determined, in order to increase M values, effectively
It is that addition participates in DI and remains the alloying element of the formation of γ phases.But from the viewpoint of cost cutting, the upper limit of M values is big
It causes to be 24.Above-mentioned M values are more preferably 17 hereinafter, further preferably 15 or less.
Next, the method for the steel plate for manufacturing embodiments of the present invention illustrates.
The steel plate of embodiments of the present invention, be will comply with conventional method it is smelting obtained from steel disc, be heated to
After 1000~1150 DEG C, depressed in the non-recrystallization temperature domain hot rolling of austenite, and by the accumulation of 830 DEG C of temperature fields below
Rate is controlled 25% or more, and finishing temperature control is manufactured at 680 DEG C or more.After finish to gauge, make average cooling rate be 4 DEG C/
Second or more and accelerate be cooled to 200 DEG C of temperature fields below.After cooling, after being heated to the temperature of two-phase section and holding, make average
Cooling velocity accelerates to be cooled to 200 DEG C of temperature fields below for 4 DEG C/sec or more, carries out temper.
Hereinafter, being described in detail.
(1) heating temperature
The steel disc that melting obtains is heated to 1000~1150 DEG C.In order to improve the pole low-temperature flexibility of steel, it is important that heat
The austenite grain of steel disc before rolling is fine, by the austenite grain miniaturization for making the steel disc before hot rolling, it can be ensured that -196 DEG C
Lower existing residual γ amounts.Therefore in embodiments of the present invention, make the steel disc before hot rolling heating temperature be 1000 DEG C with
On.Heating temperature is preferably 1010 DEG C or more, more preferably 1020 DEG C or more.But if heating temperature is excessively high, γ is coarse
Change, the deterioration of pole low-temperature flexibility.Therefore in embodiments of the present invention, it is 1150 DEG C or less to make above-mentioned heating temperature.It is above-mentioned to add
Hot temperature is preferably 1140 DEG C hereinafter, more preferably 1130 DEG C or less.
(2) hot rolling
After above-mentioned steel disc is heated to above-mentioned temperature range, hot rolling is carried out in the non-recrystallization temperature domain of austenite, is made
The accumulation reduction ratio of 830 DEG C of temperature fields below is 25% or more, and finishing temperature is made to be 680 DEG C or more.By in Ovshinsky
The non-recrystallization temperature domain of body carries out hot rolling, and it is preferably 25% or more to make the accumulation reduction ratio of 830 DEG C of temperature fields below, can
Make tissue miniaturization.Above-mentioned accumulation reduction ratio is preferably 30% or more, and more preferably 35% or more.
If above-mentioned finishing temperature less than 680 DEG C, is gathered, tissue is significantly flourishing, and pole low-temperature flexibility reduces.Therefore in this hair
In bright embodiment, above-mentioned finishing temperature is 680 DEG C or more, preferably 685 DEG C or more, more preferably 690 DEG C or more.It is above-mentioned
The upper limit of finishing temperature, for example, it is preferable to be 800 DEG C.
(3) cooling after hot rolling
After hot rolling, it is cooled to 200 DEG C of temperature fields below.The average cooling rate when cooling is 4 DEG C/sec or more.It is logical
Crossing makes average cooling rate be 4 DEG C/sec or more, martensite can be made to generate.Above-mentioned average cooling rate be preferably 5 DEG C/sec with
On, more preferably 6 DEG C/sec or more.The upper limit of above-mentioned average cooling rate is not particularly limited, but for example, it is preferable to for 50 DEG C/
Second.
The cooling temperature that stops after above-mentioned hot rolling is 200 DEG C or less.If the cooling stopping temperature after above-mentioned hot rolling
Degree is higher than 200 DEG C, then martensite is difficult to generate, therefore strength reduction.Cooling after above-mentioned hot rolling stops temperature
150 DEG C hereinafter, more preferably 100 DEG C or less.
(4) the heating temperature TL of two-phase section
It after hot rolling, is cooled to after 200 DEG C of temperature fields below, is heated to the temperature TL (DEG C) of two-phase section and keeps.It is logical
It crosses and is kept with the temperature TL heating of two-phase section, it can be by existing residual γ amounts control at -196 DEG C in defined range.
The temperature TL of so-called two-phase section, is Ac1Or more, Ac3Point temperature range below.Heating temperature is more preferably Ac1
+ 60 DEG C or more of point, more preferably Ac3- 10 DEG C or less of point.In addition, with given to this invention at the steel plate being grouped as
Ac1The temperature of point, substantially 600 DEG C, Ac3Substantially 750 DEG C of the temperature of point, the heating temperature TL of two-phase section can also be controlled
600~750 DEG C.The heating temperature TL of two-phase section is more preferably 660 DEG C or more, more preferably 740 DEG C or less.
In the present specification, Ac1Point and Ac3Point calculates (" the 4 iron steel of metallography material Knitting in lecture modern times based on following formula
Material " comes from the metallography meeting of Japan of civic organization).
Ac1Point=723-10.7 × [Mn] -16.9 × [Ni]+29.1 × [Si]+16.9 × [Cr]+290 × [As]+
6.38×[W]…(3)
Ac3Point=910-203 × [C]0.5- 15.2 × [Ni]+44.7 × [Si]+104 × [V]+31.5 × [Mo]+13.1
×[W]…(4)
In above formula, [] means with quality %, the alloying element amount in steel.In addition, in embodiments of the present invention, because
For As and W as ingredient in steel by comprising so in above formula, [As] and [W] is used as 0% to calculate.
(5) the retention time tL of two-phase section
The retention time tL (minute) of above-mentioned two-phase section is 15~40 minutes.When retention time tL is less than 15 minutes, alloy
Concentration of the element to γ phases does not carry out fully, therefore strength reduction.Retention time tL is preferably 20 minutes or more, more preferably 25
Minute or more.But if retention time tL is more than 40 minutes, α phases are annealed, strength reduction.Retention time tL is preferably 35 points
Clock is hereinafter, more preferably 30 minutes or less.
After two-phase section heating is kept, it is cooled to 200 DEG C or less.The average cooling rate when cooling as 4 DEG C/sec with
On quenched.When average cooling rate is less than 4 DEG C/sec, martensitic traoformation, strength reduction do not occur for a part for austenite
And/or residual γ amounts are insufficient.Average cooling rate is preferably 5 DEG C/sec or more, more preferably 6 DEG C/sec or more.
(6) temperature T3
It heats and keeps in two-phase section, after being cooled to 200 DEG C or less, be tempered with 550~630 DEG C of temperature.For by quenching
Martensite that is fiery and generating is tempered, and intensity can be adjusted.In addition, toughness can be improved by tempering.If temperature T3
Higher than 630 DEG C, then reverse transformation also occurs for the α phases that alloying element does not concentrate, therefore cannot get desired residual γ phases, Er Qieqiang
Degree also reduces.Therefore in embodiments of the present invention, temperature T3 is 630 DEG C or less.Temperature T3 is preferably 620 DEG C
Hereinafter, more preferably 610 DEG C or less.But if temperature is less than 550 DEG C, it is difficult to ensure residual γ amounts.Therefore it is tempered temperature
The lower limit of degree is 550 DEG C or more.Temperature is preferably 560 DEG C or more, more preferably 570 DEG C or more.
(7) tempering time t3
Tempering time t3 (minute) is 15 minutes or more.When t3 is less than 15 minutes, the reverse transformation of the α phases of alloying element concentration
It does not carry out fully, therefore cannot get desired residual γ phases.The upper limit of retention time is not particularly limited, but from productivity
Viewpoint is set out, preferably 40 minutes.Tempering time t3 is more preferably 30 minutes or less.
The steel plate of the embodiments of the present invention so manufactured, it is also -196 DEG C tolerable other than having high intensity
Extremely low temperature high tenacity, thus it is for example possible to suitable for liquefied natural gas storage tank former material.That is, the implementation of the present invention
The steel plate of mode, it is 690~830MPa to have tensile strength, and yield strength is the such high intensity of 590MPa or more, and
At -196 DEG C carry out pendulum impact test when percentage of brittle fracture surface 10% hereinafter, absorb can minimum meet 150J with
On, pole excellent in low temperature toughness.It can ensure 150J or more especially as the minimum for absorbing energy, therefore can ensure minimum product
Matter, and the safety of actual container can then further increase.
Hereinafter, enumerating embodiment further illustrates the present invention, but the present invention is not limited by following embodiments, it is of course possible to
Implementation is changed in the range that can meet aforementioned and aftermentioned objective, these are all contained in the technical scope of the present invention.
【Embodiment】
Melting, casting are containing ingredient shown in following table 1-1 or table 1-2, and surplus is by iron and inevitable impurity structure
At steel, manufacture steel disc.In following table 1-1 or table 1-2, describes be based on above formula (2) calculated DI together, be based on above formula
(3) calculated Ac1Point is based on above formula (4) calculated Ac3Point.
The steel disc that will be obtained, after being heated to heating temperature shown in following table 2-1 or table 2-2, in non-recrystallization temperature
Domain is rolled.The accumulation reduction ratio of 830 DEG C of temperature fields below is shown in following table 2-1 or table 2-2.In addition, finish to gauge
Temperature (FRT) is shown in following table 2-1 or table 2-2.
After finish to gauge, make to stop temperature from the beginning of cooling temperature (SCT) shown in following table 2-1 or table 2-2 to cooling
(FCT) average cooling rate is 4 DEG C/sec or more in region, manufactures the thick steel of plate thickness shown in following table 2-1 or table 2-2
Plate.
The steel plate that will be obtained is heated to two-phase section heating temperature TL shown in following table 2-1 or table 2-2, with this temperature
It spends TL and keeps time tL shown in following table 2-1 or table 2-2.In addition, in following table 2-1 and table 2-2, as with reference to value
Show A shown in following table 1-1 and table 1-2c1The temperature and A of pointc3The temperature of point.
After holding, the average cooling rate by 200 DEG C of temperature below is made to be cooled down for 4 DEG C/sec or more.
Then, after carrying out temper, it is air-cooled to room temperature.In following table 2-1 or table 2-2, temperature T3 is shown
With tempering time t3.
For the obtained steel plate, the volume fraction of existing residual γ phases at -196 DEG C is measured.That is, setting thick steel
When the plate thickness of plate is t, in a manner of including the steel of the part comprising the positions t/4, the test film of 10mm × 10mm × 55mm is extracted,
It is kept for 5 minutes at the temperature (- 196 DEG C) of liquid nitrogen.Thereafter, test film is ground and is ground, test film after grinding
Surface makes the positions t/4 of the plate thickness of steel plate expose.With the sample horizontal type strength X-ray diffraction device (RINT- of リ ガ Network society
TTRIII), X-ray diffraction measurement is carried out using Co radiographic sources.Then, for (110) of ferritic phase, (200), (211)
The peak value of each lattice plane, and the peak value of each lattice plane of (111) of γ phases, (200), (220), (311) is remained, calculate each peak value
Integrated intensity.The sum of the integrated intensity of the sum of integrated intensity of each peak value according to ferritic phase and each peak value of residual γ phases
Ratio, and by simulating the sensitivity coefficient of " 3 lattice planes of ferritic phase and 4 lattice planes of austenite phase " acquired,
Calculate the volume fraction (%) of residual γ phases.As a result it is shown in following table 2-1 or table 2-2.
In addition, in following table 2-1 or table 2-2, describes constitute ginseng based on the calculated section elements of above formula (1) together
Number M values.
Then, for obtained steel plate, evaluation
(a) mechanical characteristic (tensile strength TS, yield strength YS), and
(b) (absorption carried out at -196 DEG C when the pendulum impact test in the directions C can be with brittleness section for pole low-temperature flexibility
Rate).
(a) mechanical characteristic (tensile strength TS, yield strength YS)
If the plate thickness of steel plate be t, plate thickness t higher than 20mm steel plate in, from the positions t/4, it is parallel with the directions C into
No. 4 test films for extracting JIS Z2241, in plate thickness t is 20mm steel plates below, from the positions t/4, parallelly with the directions C
No. 5 test films for extracting JIS Z2241 carry out tension test based on the method described in JIS Z2241, measure tensile strength TS
With yield strength YS.Measurement result is shown in following table 2-1 and table 2-2.
Tensile strength TS is 690MPa or more, 830MPa hereinafter, also, yield strength YS when being 590MPa or more, judgement
For qualification, it is evaluated as high intensity.On the other hand, when tensile strength TS is less than 590MPa less than 690MPa or yield strength YS, sentence
It is set to unqualified, is evaluated as low-intensity.In addition, even if yield strength in 590MPa or more, if tensile strength TS is higher than
830MPa is also determined as unqualified then because intensity is excessively high.
(b) pole low-temperature flexibility
If the plate thickness of steel plate is t, in steel plates of the plate thickness t higher than 10mm, from the positions t/4, parallelly with the directions C
The V notch test sheets for extracting 3 JIS Z2242 extract the pendulum of 3 small sizes in plate thickness t is 10mm steel plates below
Impact test piece carries out pendulum impact test based on the method described in JIS Z2242 at -196 DEG C, measures and absorbs energy (J).
Among the result of 3 test films, using minimum as the absorption energy vE at -196 DEG C- 196。
In addition, the test film of minimum can be shown as absorption, JIS Z2242 are based on, measure percentage of brittle fracture surface (%).
Absorption can be interrelated with percentage of brittle fracture surface, is based on absorbing smaller, this bigger rule of thumb of percentage of brittle fracture surface of test film of energy,
Using the percentage of brittle fracture surface for the test film for absorbing energy minimum among 3 test films as typical value.
In addition, the absorption energy of the pendulum impact test piece about small size, is allowed to be equivalent to the Charpy impact examination of full size
It tests the absorption energy of piece and converts.
The minimum vE for absorbing energy measured with -196 DEG C- 196For 150J or more, also, percentage of brittle fracture surface be 10% with
When lower, it is determined as qualification, is evaluated as pole excellent in low temperature toughness.On the other hand, the minimum for absorbing energy measured with -196 DEG C
vE- 196Less than 150J or when percentage of brittle fracture surface is higher than 10%, it is determined as unqualified.
Above-mentioned section elements constitute parameter M values and the relationship of above-mentioned percentage of brittle fracture surface is shown in Fig. 1.In addition, in Fig. 1,
Only depict into the example for being grouped as and meeting important document given to this invention.That is, the ◇ of Fig. 1, indicates No.1 shown in table 2-1
~15 as a result, the ■ of Fig. 1 indicate No.16~19 shown in table 2-2,32 result.
It can be investigated as follows based on following table 2-1, table 2-2, Fig. 1.
No.1~15 of table 2-1 are the examples for meeting important document given to this invention.As shown in table 2-1, tensile strength
TS is 690~830MPa, also, yield strength YS is 590MPa or more, has high intensity.Moreover, passing through pendulum at -196 DEG C
When impact test measures the absorption energy of 3 test films, the minimum vE of energy is absorbed- 196For 150J or more, also, show minimum
Absorb can the percentage of brittle fracture surface of test film be 10% hereinafter, pole low-temperature flexibility is also excellent.
On the other hand, No.16~32 of table 2-2 are the examples for being unsatisfactory for some important document of defined of the present invention.Therefore, such as
Shown in table 2-2, intensity and pole low-temperature flexibility cannot be made to exist side by side.
That is, No.16,17 because section elements constitute parameter M values be less than 2.4, with -196 DEG C measure absorb can
Minimum vE- 196Low, percentage of brittle fracture surface is high, cannot improve pole low-temperature flexibility.
No.18 cannot ensure the existing residual γ amounts at -196 DEG C because the heating time tL of two-phase section is short,
Section component unit parameter M values are less than 2.4.As a result, percentage of brittle fracture surface is high, pole low-temperature flexibility cannot be improved.
No.19 cannot ensure the required retained austenite scale of construction for meeting M values, result because temperature T is low
It is that percentage of brittle fracture surface is high, cannot improve pole low-temperature flexibility.
No.20 is that C amounts, Si amounts and Mn amounts are more, the few example of Cr amounts, cannot ensure existing residual γ amounts at -196 DEG C,
Section component unit parameter M values are less than 2.4.As a result, pole low-temperature flexibility cannot be improved.In addition, because martensite increases, institute
It is excessively high with tensile strength TS.
No.21 is that the V amounts of Al amounts, Cr amounts and Mo amounts and alternatively ingredient are more, C amounts and the few example of Ni amounts.It is tied
Fruit is that tensile strength TS is low, cannot ensure the residual γ amounts at -196 DEG C, therefore cannot improve pole low-temperature flexibility.
No.22 is the more example of Si amounts, cannot improve pole low-temperature flexibility.In addition, it is free from Cr, and the more example of V amounts, tension
Intensity TS is excessively high, therefore cannot improve pole low-temperature flexibility.
No.23 is that Mn amounts, P amounts and Mo amounts are more, is free of the example of Cr, and temperature T3 is less than 550 DEG C, therefore cannot be true
Protect existing residual γ amounts at -196 DEG C.As a result, section component unit parameter M values are less than 2.4, extremely low temperature cannot be improved
Toughness.
No.24 is that Mn amounts are few, and P amounts and Cr amounts are more, are free of the example of Mo, cannot ensure the residual γ amounts at -196 DEG C.Its
As a result, pole low-temperature flexibility cannot be improved.
No.25 is the more example of S amounts.As a result, pole low-temperature flexibility cannot be improved.In addition, being that Cr amounts are few, it is alternatively that
The more example of the Cu amounts of ingredient.As a result, tensile strength TS becomes excessively high, pole low-temperature flexibility deteriorates instead.
No.26 is that Mn amounts and Al amounts are more, is free of the example of Mo.As a result, pole low-temperature flexibility cannot be improved.In addition, because
More for Nb amounts, so tensile strength TS too greatly rises, pole low-temperature flexibility deteriorates instead.
No.27 is that Ni amounts are few, is free of the example of Cr and Mo, and residual γ amounts are cannot ensure at -196 DEG C.As a result,
Percentage of brittle fracture surface is high, cannot improve pole low-temperature flexibility.
For No.28 because Ni amounts are few, Cu is more, so percentage of brittle fracture surface is high, cannot improve pole low-temperature flexibility.In addition, being Cr amounts
Few example.As a result, yield strength YS is reduced, intensity cannot be improved.
No.29 is the more example of Cr amounts and Ti amounts, because tensile strength TS is excessively high, pole low-temperature flexibility deteriorates instead.
In addition, because S amounts are more, percentage of brittle fracture surface is high, cannot improve pole low-temperature flexibility.
No.30 is that N amounts are more, Al amounts and the few example of Cr amounts.As a result, percentage of brittle fracture surface is high, extremely low temperature cannot be improved
Toughness.
No.31 is the more example of Mo amounts.As a result, tensile strength TS becomes excessively high, pole low-temperature flexibility cannot be improved.
No.32 cannot ensure the desired retained austenite scale of construction, can not meet accompanying this because tempering t3 is short
M values cannot improve pole low-temperature flexibility the result is that percentage of brittle fracture surface is high.
The application is with the Japanese Patent Application that the applying date is on December 18th, 2015, Patent 2015-247748
The claim of priority applied based on number.Patent the 2015-247748th because with reference to due to be incorporated into this specification.
Claims (3)
1. a kind of steel plate of pole excellent in low temperature toughness, which is characterized in that be following steel plate, contained in terms of quality %
C：0.04~0.09%,
Si：Higher than 0% and below 0.30%,
Mn：0.50~1.10%,
P：Higher than 0% and below 0.004%,
S：Higher than 0% and less than 0.0030%,
Al：0.010~0.040%,
Ni：5.50~7.5%,
Cr：0.30~0.6%,
Mo：Higher than 0% and below 0.20% and
N：Higher than 0% and 0.0055% hereinafter,
Surplus is made of iron and inevitable impurity,
The volume fraction v of existing retained austenite phase is 4.0~12% at -196 DEG C, also,
If the plate thickness of the steel plate is t, section elements shown in following formula (1) constitute parameter M values and meet 2.4 or more,
M values=(DI × v2)/t…(1)
In above formula (1), DI is by following formula (2) calculated value, and [] indicates the content of each element in terms of quality %,
DI=1.16 × ([C]/10)0.5×(0.7×[Si]+1)×(1+3.33×[Mn])×(1+0.35×[Cu])×(1+
0.36×[Ni])×(1+2.16×[Cr])×(1+3×[Mo])×(1+1.75×[V])×1…(2)。
2. steel plate according to claim 1, wherein also contain Cu in terms of quality %：Higher than 0% and below 0.3%
As other elements.
3. steel plate according to claim 1 or 2, wherein in terms of quality % also contain from
Nb：Higher than 0% and below 0.03%,
Ti：Higher than 0% and below 0.025% and
V：What is selected in the group constituted higher than 0% and below 0.03% is at least one as other elements.
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| JP2015-247748 | 2015-12-18 | ||
| PCT/JP2016/086863 WO2017104599A1 (en) | 2015-12-18 | 2016-12-12 | Thick steel plate having excellent cryogenic toughness |
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| CN108368579A true CN108368579A (en) | 2018-08-03 |
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| EP (1) | EP3392361A4 (en) |
| JP (1) | JP2017115239A (en) |
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| CN109280848A (en) * | 2018-10-17 | 2019-01-29 | 东北大学 | A kind of low-nickel type LNG tank steel plate and preparation method thereof |
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| CN111263827B (en) * | 2017-10-26 | 2021-12-21 | 日本制铁株式会社 | Nickel-containing steel for low temperature use |
| US11384416B2 (en) | 2017-10-26 | 2022-07-12 | Nippon Steel Corporation | Nickel-containing steel for low temperature |
| CN111263828B (en) * | 2017-10-26 | 2021-08-17 | 日本制铁株式会社 | Nickel-containing steel for low temperature use |
| US11371127B2 (en) | 2017-10-26 | 2022-06-28 | Nippon Steel Corporation | Nickel-containing steel for low temperature |
| JP6394835B1 (en) * | 2017-10-31 | 2018-09-26 | 新日鐵住金株式会社 | Low temperature nickel-containing steel sheet and low temperature tank using the same |
| KR102075206B1 (en) | 2017-11-17 | 2020-02-07 | 주식회사 포스코 | Low temperature steeel plate having excellent impact toughness property and method for manufacturing the same |
| KR102043523B1 (en) | 2017-12-24 | 2019-11-12 | 주식회사 포스코 | Low temperature steel materal having excellent toughness in welded zone and method for manufacturing the same |
| JP7251512B2 (en) * | 2020-04-08 | 2023-04-04 | Ｊｆｅスチール株式会社 | Steel plate and its manufacturing method |
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| CN104583439A (en) * | 2012-08-23 | 2015-04-29 | 株式会社神户制钢所 | Thick steel plate having good ultralow-temperature toughness |
| CN104854252A (en) * | 2012-12-13 | 2015-08-19 | 株式会社神户制钢所 | Thick steel plate having excellent cryogenic toughness |
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| JPS5512083B2 (en) | 1973-05-04 | 1980-03-29 | ||
| JPS5113308A (en) | 1974-07-24 | 1976-02-02 | Nippon Steel Corp | TEIONYOKYOJINKOOYOBISONO NETSUSHORIHOHO |
| JP5513254B2 (en) | 2010-05-17 | 2014-06-04 | 新日鐵住金株式会社 | Low temperature steel plate and method for producing the same |
| WO2012005330A1 (en) * | 2010-07-09 | 2012-01-12 | 新日本製鐵株式会社 | Ni-CONTAINING STEEL SHEET AND PROCESS FOR PRODUCING SAME |
| JP6018453B2 (en) * | 2012-03-09 | 2016-11-02 | 株式会社神戸製鋼所 | High strength thick steel plate with excellent cryogenic toughness |
| JP6018454B2 (en) * | 2012-04-13 | 2016-11-02 | 株式会社神戸製鋼所 | High strength thick steel plate with excellent cryogenic toughness |
| JP5973902B2 (en) * | 2012-12-13 | 2016-08-23 | 株式会社神戸製鋼所 | Thick steel plate with excellent cryogenic toughness |
| JP5973907B2 (en) * | 2012-12-27 | 2016-08-23 | 株式会社神戸製鋼所 | Thick steel plate with excellent cryogenic toughness |
| JP6055363B2 (en) * | 2013-04-17 | 2016-12-27 | 株式会社神戸製鋼所 | High strength thick steel plate with excellent cryogenic toughness |
| JP5556948B1 (en) * | 2013-10-28 | 2014-07-23 | Ｊｆｅスチール株式会社 | Low temperature steel sheet and method for producing the same |
| JP6196929B2 (en) * | 2014-04-08 | 2017-09-13 | 株式会社神戸製鋼所 | Thick steel plate with excellent HAZ toughness at cryogenic temperatures |
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2016
- 2016-12-08 JP JP2016238829A patent/JP2017115239A/en active Pending
- 2016-12-12 EP EP16875576.7A patent/EP3392361A4/en not_active Withdrawn
- 2016-12-12 KR KR1020187017177A patent/KR20180086443A/en not_active Application Discontinuation
- 2016-12-12 WO PCT/JP2016/086863 patent/WO2017104599A1/en active Application Filing
- 2016-12-12 CN CN201680073537.8A patent/CN108368579A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104583439A (en) * | 2012-08-23 | 2015-04-29 | 株式会社神户制钢所 | Thick steel plate having good ultralow-temperature toughness |
| CN104854252A (en) * | 2012-12-13 | 2015-08-19 | 株式会社神户制钢所 | Thick steel plate having excellent cryogenic toughness |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109280848A (en) * | 2018-10-17 | 2019-01-29 | 东北大学 | A kind of low-nickel type LNG tank steel plate and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2017115239A (en) | 2017-06-29 |
| EP3392361A4 (en) | 2019-06-12 |
| WO2017104599A1 (en) | 2017-06-22 |
| EP3392361A1 (en) | 2018-10-24 |
| KR20180086443A (en) | 2018-07-31 |
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