CN105102651B - The Large Heat Input Welding high-strength steel sheet and its manufacture method of excellent in brittle-cracking propagation stopping characteristics - Google Patents
The Large Heat Input Welding high-strength steel sheet and its manufacture method of excellent in brittle-cracking propagation stopping characteristics Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
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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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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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
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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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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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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
- C21D2201/00—Treatment for obtaining particular effects
- C21D2201/05—Grain orientation
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/004—Dispersions; Precipitations
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Abstract
The present invention provides the Large Heat Input Welding high-strength steel sheet and its manufacture method of the excellent in brittle-cracking propagation stopping characteristics of more than thickness of slab 50mm suitable for ship a kind of.A kind of steel plate and its manufacture method, there is the steel plate specific composition to form, metal structure is the tissue based on ferritic phase, aggregation degree with the RD/ in thickness of slab skin section/(110) face is the texture that the aggregation degree in RD//(110) face in more than 1.3, thickness of slab central portion is more than 1.8, and the Charpy fracture transition temperature vTrs of thickness of slab skin section and thickness of slab central portion is less than 50 DEG C.
Description
Technical field
The present invention relates to the excellent big line of brittle-cracking propagation stopping characteristics (brittle crack arrestability)
High-strength steel sheet (high-strength thick steel are used in energy welding (high heat input welding)
Plate) and its manufacture method, the high-strength steel sheet being more particularly to suitable for more than the thickness of slab 50mm of ship.
Background technology
For the large structures such as ship, accident is to economy caused by brittle fracture (brittle fracture)
With environment caused by influence it is very big.Therefore, raising security is usually required that, for used steel, it is desirable under temperature in use
Tough (toughness) and brittle-cracking propagation stopping characteristics.
The thick-wall materials of high intensity are used for ship hull plate (outer by the ships such as container ship, bulk carrier in its structure
plate of ship's hull).Recently, with the maximization of hull, further development of high strength wall thickening, generally,
The brittle-cracking propagation stopping characteristics of steel plate have high intensity or the tendency that thick-wall materials are more deteriorated, therefore, to crisp
The requirement of property crack propagation stop performance also further improves.
Side as the method for improving the brittle-cracking propagation stopping characteristics of steel, all the time known increase Ni contents
Method, in liquefied natural gas (LNG：Liquefied Natural Gas) storage tank in, 9%Ni steel is used with commercial size.
But the increase of Ni amounts has to be substantially increased cost, accordingly, it is difficult to applied to the purposes beyond LNG storage tank.
On the other hand, for be not reaching to extremely low temperature (ultra low temperature) as LNG, for ship
Oceangoing ship or pipeline, steel that thickness of slab is relatively thin less than 50mm ratio, can pass through TMCP (Thermo-Mechanical Control
Process, thermomechanically controlling technique) method realizes grain refined and improves Di Wen Tough, passed so as to assign excellent brittle crack
Broadcast stop performance.
In addition, proposed in patent document 1 to make brittle-cracking propagation on the premise of cost of alloy is increased
Stop performance improve and by the steel of the tissue micronization (ultra fine grained steel) of skin section.
The steel for the excellent in brittle-cracking propagation stopping characteristics that patent document 1 is recorded are characterised by, are conceived to fragility and are split
Line stops when propagating in shear lip (plastic deformation area shear-lips) caused by steel thickness of slab skin section to brittle-cracking propagation
Only the raising of characteristic is effective, makes the crystal grain miniaturization of shearing lip portion, so as to absorb propagation possessed by the brittle crack of propagation
Energy.
In addition, following content is recorded in patent document 1：Cooled down by the control after hot rolling thickness of slab surface part is cold
But to Ar3Transformation temperature (transformation point) below, then, stops control cooling (controlled
Cooling), by more than thickness of slab surface part reheating (recuperate) to transformation temperature, more than 1 time above-mentioned work is repeated
Sequence, during this period steel are implemented to roll, it is repeated phase transformation or processing recrystallization, generated in thickness of slab surface part
Ultra tiny ferritic structure (ferrite structure) or bainite structure (bainite structure).
In addition, following content is recorded in patent document 2：For being used as main body using ferrite-pearlite (pearlite)
The steel of microscopic structure, in order that brittle-cracking propagation stopping characteristics improve, it is important that two surface elements of steel by with
The layer of more than 50% ferritic structure is formed, and the ferritic structure has circle equivalent grain size (circle-equivalent
Average grain size) it is less than 5 μm, the iron element that draw ratio (aspect ratio of the grains) is more than 2
Body crystal grain, and suppress the deviation of ferrite particle diameter.As the method for suppressing deviation, by the maximum of every 1 passage in finish rolling
Reduction ratio (maximum rolling reduction) is set as less than 12%, so as to suppress local recrystallization phenomenon.
But the steel of the excellent in brittle-cracking propagation stopping characteristics described in patent document 1,2 are by only by steel
Reheated again after the temporarily cooling of thickness of slab skin section and implement processing in reheating and specifically organized, therefore,
It is difficult to control under actual production scale.For thick-wall materials of the thickness of slab more than 50mm, set to rolling, cooling down
The big technique of standby load.
On the other hand, the miniaturization for being not only conceived to ferrite crystal grain has been recorded in patent document 3 but also has been conceived to be formed
Subgrain (subgrain) in ferrite crystal grain and the TMCP elongation technologies for improving brittle-cracking propagation stopping characteristics.
Specifically, in the case where thickness of slab is 30~40mm steel plate, without carrying out the cooling and again on steel plate top layer
The complicated temperature control such as heating, improves brittle-cracking propagation stopping characteristics by following conditions：(a) fine iron element is ensured
The rolling condition of body crystal grain, (b) generated in more than 5% part of steel thickness of slab fine ferrite structure rolling condition,
(c) dislocation that makes texture (texture) flourishing in fine ferrite and will be introduced using heat energy by processing (rolling)
(dislocation) it is reconfigured at and forms the rolling condition of subgrain, (d) suppresses the fine ferrite crystal grain of formation and fine Asia
The cooling condition of the coarsening of crystal grain.
In addition, it is also known that rolling is applied to the ferrite after phase transformation in controlled rolling and makes that texture is flourishing, it is crisp thus to make
Property the method that improves of crack propagation stop performance.This method on the plane of disruption of steel along the direction parallel with plate face by producing
Raw breach (separation) and relax the stress of brittle crack front end to improve the resistance to brittle fracture.
For example, following content is recorded in patent document 4：(110) face X-ray intensity ratio (X-ray is made by controlled rolling
Plane intensity ratio in the (110) plane showing a texture developing degree) be
More than 2 and make to justify equivalent diameter (diameter equivalent to a circle in the crystal grains)
More than 20 μm of coarse grain is less than 10%, thus improves resistance to brittle fracture characteristic.
Patent Document 5 discloses a kind of welding structure of the excellent in brittle-cracking propagation stopping characteristics as seam
With the steel plate of steel, it is characterised in that the X ray surface intensity ratio in (100) face on the rolling surface inside thickness of slab is more than 1.5,
And describing can be obtained using the angular deviation in mechanical load direction and crack propagation direction as caused by the texture prosperity
To excellent brittle-cracking propagation stopping characteristics.
Prior art literature
Patent document
Patent document 1：Japanese Patent Publication 7-100814 publications
Patent document 2：Japanese Unexamined Patent Publication 2002-256375 publications
Patent document 3：No. 3467767 publications of Japanese Patent No.
Patent document 4：No. 3548349 publications of Japanese Patent No.
Patent document 5：No. 2659661 publications of Japanese Patent No.
Patent document 6：No. 3546308 publications of Japanese Patent No.
Non-patent literature
Non-patent literature 1：Well is first-class：Thick hand shipbuilding splits Den with the big fragility I of Steel To お け る Long and broadcasts Behavior Move (heavy wall shipbuildings
With the brittle-cracking propagation characteristic of growing up of steel), Japanese ship ocean engineering can give a lecture the phase of collection of thesis the 3rd, 2006, pp359~362
The content of the invention
Invent problem to be solved
Recently, big more than 6000TEU (Twenty-foot Equivalent Unit, twenty-foot equivalent unit)
In type container ship, 50mm steel plate is exceeded using thickness of slab.In non-patent literature 1, to the brittle crack of thickness of slab 65mm steel plate
Propagation halt characteristic is evaluated, and reports the brittle crack in the large-scale brittle-cracking propagation of mother metal stops experiment and do not have
There is the result of stopping.
In addition, in the standard ESSO experiments (ESSO test compliant with WES3003) of material to be tested, show
Show that the value (following, to be also recited as Kca (- 10 DEG C)) of the Kca under -10 DEG C of temperature in use is less than 3000N/mm3/2Knot
Fruit, in the case of the Ship Structure of steel plate of the application thickness of slab more than 50mm, suggesting ensures that security turns into problem.
From the point of view of manufacturing condition, disclosed experimental data, the brittle-cracking propagation described in above-mentioned patent document 1~5 stops
Only the steel plate of characteristic good is using the steel plate of about 50mm thickness of slab as main object.By the technology application described in patent document 1~5
In the case of the thick-wall materials more than 50mm, it is unclear that defined characteristic can be obtained, for the required pin of institute in Ship Structure
To the characteristic of the crack propagation in thickness of slab direction, it is not verified completely.
On the other hand, along with the wall thickening of steel plate, submerged-arc welding (submerged arc are applied in welding procedure
Welding), electrogas arc welding (electrogas arc welding) and electroslag welding (electroslag welding) etc. are efficient
The Large Heat Input Welding of (high efficiency).If it is generally known that weld heat input increase, welding heat affected zone
(Heat Affected Zone；HAZ tissue coarsening), therefore, the toughness of welding heat affected zone decline.In order to solve by this
The problem of toughness caused by the Large Heat Input Welding of sample reduces, high input energy welding steel material is had been developed for, and it is practical
Change.For example, Patent Document 6 discloses following technology：The TiN separated out by controlling in steel, prevent welding heat affected zone tissue
Coarsening (coarsening), while the scattered of core is generated by ferrite, promotes ferrite transformation in crystal grain, thus make weldering
Connect the high toughening of heat affected zone.However, although the good-toughness of the welding heat affected zone in Large Heat Input Welding portion, does not consider fragility
Crack propagation stop performance, do not obtain the steel for meeting two characteristics.
Therefore, it is an object of the present invention to provide can control thickness of slab direction by optimizing composition of steel and rolling condition
On texture industrial extremely easy technique come the big line energy of excellent in brittle-cracking propagation stopping characteristics that stably manufactures
Measure welding high-strength steel sheet and its manufacture method.
For solving the method for problem
The present inventors is in order to realize that in-depth study has been repeated in above-mentioned problem, even also having on thick steel sheet
The high-strength steel plate for having excellent crack propagation stop performance obtains following opinion.
1. exceed 50mm steel plate for thickness of slab, the fracture of detailed examination standard ESSO experiments, as a result, as such as figure
In the case of fracture morphology shown in 1 (b), reduce with the width of brittle crack, the stress magnification factor of crackle leading section subtracts
Small, as a result the crack arrest characteristic of steel plate improves.Fig. 1 (a) (b) schematically illustrate standard ESSO test films 1 from breach 2 enter
Crackle 3 stops propagating in mother metal 5 with front end geometry 4.
2. in order to obtain fracture morphology as described above, it is necessary to improve the crack arrest of thickness of slab skin section and thickness of slab central portion
Energy.As the method for improving the crack arrest characteristic of thickness of slab skin section and thickness of slab central portion, make thickness of slab skin section and thickness of slab central portion
It is effective that Tough, which are improved,.But for thickness of slab is more than steel plate as 50mm, cooling velocity and reduction ratio etc. are deposited
Limiting, hence for thickness of slab central portion Tough are improved, there is also boundary.
3. as the method in addition to improving toughness improving also crack arrest characteristic, the texture of control thickness of slab central portion is that have
Effect, especially with respect to rolling direction gather abreast (110) face, so that what is developed on rolling direction or plate width direction splits
It is effective that the mode that line obliquely deviates from rolling direction or plate width direction respectively, which carries out texture controlling,.
4. in addition, by making the accumulation reduction ratio in the state of thickness of slab central portion is in austenite recrystallization temperature area be
More than 20%, and make every 1 passage average reduction ratio be less than 5.0%, realize the miniaturization of the tissue of thickness of slab skin section.
Then, by make accumulation reduction ratio in the state of thickness of slab central portion is in austenite non-recrystallization humidity province for 40% with
On, and make the average reduction ratio of every 1 passage be more than 7%, the Tough of thickness of slab central portion and texture can be made flourishing, so as to
Above-mentioned tissue can be realized.
5. the method for the toughness as raising Large Heat Input Welding portion, effectively make TiN, CaS and MnS composite sulfuration
Thing is finely split, and suppresses to be exposed to grain growth during high temperature because of welding, and promote in cooling procedure afterwards in crystal grain
Phase transformation, so as to make heat affected zone tissue miniaturization at room temperature.
The present invention is further to be studied and completed on the basis of resulting opinion.That is, the present invention is：
A kind of 1. Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics, it is characterised in that
Steel composition contains C in terms of quality %：0.03~0.15%, Si：Less than 0.50%, Mn：1.0~2.0%, P：Less than 0.030%,
S：0.0005~0.0040%, Al：0.005~0.10%, Ti：0.004~0.030%, N：Less than 0.0036~0.0075%,
Ca：0.0005~0.0030%, O：Less than 0.0040%, also, Ca, O, S each content meet following formula (1), surplus by Fe and
Inevitable impurity is formed, and metal structure has gathering for RD//(110) face in thickness of slab skin section based on ferrite
The aggregation degree spent for the RD/ in more than 1.3, thickness of slab central portion/(110) face is more than 1.8 texture, thickness of slab skin section and thickness of slab
The Charpy fracture transition temperature vTrs of central portion is less than -50 DEG C,
0 ＜ (Ca- (0.18+130 × Ca) × O)/1.25/S≤0.8 (1)
Wherein, in formula (1), Ca, O, S are content (quality %).
2. the Large Heat Input Welding high-strength steel sheet of the excellent in brittle-cracking propagation stopping characteristics according to 1, it is special
Sign is, under the aggregation degree satisfaction in Charpy fracture transition temperature and RD//(110) face of thickness of slab skin section and thickness of slab central portion
(2) formula is stated,
vTrs(top layer)+1.9×vTrs(1/2t)-6×IRD//(110) [top layer]-84×IRD//(110)[1/2t]≤-350···(2)
Wherein, in formula (2),
vTrs(top layer)：The Charpy fracture transition temperature (DEG C) of thickness of slab skin section,
vTrs(1/2t)：The Charpy fracture transition temperature (DEG C) of thickness of slab central portion (t/2),
IRD//(110) [top layer]：The aggregation degree in the RD/ of thickness of slab skin section/(110) face,
IRD//(110)[1/2t]：The aggregation degree in the RD/ of thickness of slab central portion (t/2)/(110) face,
It should be noted that t is thickness of slab (mm).
3. the Large Heat Input Welding high-strength steel sheet of the excellent in brittle-cracking propagation stopping characteristics according to 1 or 2, its
It is characterised by, steel composition further contains Nb in terms of quality %：0.003~0.050%, Cu：Less than 0.5%, Ni：1.0% with
Under, Cr：Less than 0.5%, Mo：Less than 0.5%, W：Less than 0.4%, V：Less than 0.2%, B：One in 0.0003~0.0030%
Kind is two or more.
4. the Large Heat Input Welding of the excellent in brittle-cracking propagation stopping characteristics according to any one of 1~3 is with high-strength
Spend steel plate, it is characterised in that steel composition further contains Mg in terms of quality %：0.0005~0.0050%, Zr：0.001~
0.020%th, REM：More than one or both of 0.001~0.020%.
5. a kind of manufacture method of the Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics, its
It is characterised by, the steel former material with the composition any one of 1,3 or 4 is heated to 900~1150 DEG C of temperature, implemented
The accumulation reduction ratio of austenite recrystallization temperature area and austenite non-recrystallization humidity province adds up to more than 65%, in thickness of slab center
The accumulation reduction ratio that portion is in the state of austenite recrystallization temperature area is the mean pressure of more than 20% and every 1 passage
Lower rate is less than 5.0% rolling, then, is carried out in the state of thickness of slab central portion is in austenite non-recrystallization humidity province
It is more than 40% and rolling that the average reduction ratio of every 1 passage is more than 7.0% to accumulate reduction ratio, then, with 4.0 DEG C/
More than s cooling velocity is cooled to less than 600 DEG C.
6. the manufacture of the Large Heat Input Welding high-strength steel sheet of the excellent in brittle-cracking propagation stopping characteristics according to 5
Method, it is characterised in that after being cooled to below 600 DEG C, further have and be tempered to AC1The process of the following temperature of point.
Invention effect
According to the present invention, obtain the texture on thickness of slab direction and obtain suitable control, excellent in brittle-cracking propagation stopping characteristics
Large Heat Input Welding high-strength steel sheet and its manufacture method.Apply the present invention to more than thickness of slab 50mm, preferably thickness of slab surpasses
Cross 50mm, more preferably more than thickness of slab 55mm, further preferred more than thickness of slab 60mm steel plate, played relative to the steel of prior art
More significant superiority, therefore be effective.Moreover, for example in shipbuilding field, large-scale container ship, bulk carrier it is strong
In strength deck portion structure, by applied to hatch side coaming, deck member, being favorably improved the security of ship, therefore, producing
It is extremely useful in industry.
Brief description of the drawings
Fig. 1 is the figure of the fracture morphology for the standard ESSO experiments for showing schematically steel plate of the thickness of slab more than 50mm, and (a) is
The figure of top view test film, (b) are the figures for the fracture for representing test film.
Embodiment
In the present invention, to 1. steel composition, 2. thickness of slab skin sections and central portion Tough and texture, 3. metal structures, with
And 4. manufacturing condition provided.
1. steel forms
Hereinafter, the preferable chemical composition in the present invention is illustrated.In explanation, % is quality %.
C：0.03~0.15%
C is the element for the intensity for improving steel, in of the invention, in order to ensure desired intensity, it is necessary to contain more than 0.03%.
When on the other hand, more than 0.15%, not only weldability is deteriorated, and Dui Tough also have harmful effect.Therefore, it is 0.03 to make C
~0.15%.Preferably 0.05~0.15%.
Si：Less than 0.50%
Si as deoxidant element and as steel intensified element be it is effective, but content be less than 0.01% when, may not have
There is its effect.When on the other hand, more than 0.50%, not only damage the surface texture of steel, Er Qie Tough are deteriorated.Therefore, it is added
Measure as less than 0.50%.Preferably 0.01~0.40% scope.
Mn：1.0~2.0%
Mn adds as intensified element.During less than 1.0%, its effect is insufficient.When on the other hand, more than 2.0%, make weldering
The degraded toughness of socket part.Therefore, it is 1.0~2.0% to make Mn.Preferably 1.1~1.8% scope.
P：Less than 0.030%
P is inevitable mixed impurity, during more than 0.030%, makes the reduction of the toughness of mother metal and weld part.Therefore, make
The upper limit is 0.030%.
S：0.0005~0.0040%
More than 0.0005% is necessary in order to generate required CaS or MnS, S.When on the other hand, more than 0.0040%,
Make the degraded toughness of mother metal.Therefore, it is 0.0005~0.0040% to make S.
Al：0.005~0.10%
Al works as deoxidier, is needed for this containing more than 0.005%.But containing when having more than 0.10%, Tough can be made
Property reduce, and make when being welded welding metal Bu Tough reductions.Therefore, Al is defined as 0.005~0.10%
Scope.Preferably 0.005~0.08%, it is more preferably 0.02~0.06%.
Ti：0.004~0.030%
For Ti, by micro addition, nitride, carbide or carbonitride are formed, is suppressed welding heat affected
The coarsening of the austenite in portion, and/or promote ferrite transformation as ferrite transformation core, thus having makes crystal grain miniaturization
And improve Mu Cai Tough effect.Its effect is obtained by more than 0.004% addition.But containing when having more than 0.030%, make
TiN particle coarsenings, thus reduce mother metal and welding heat affected zone Tough.Therefore, it is 0.004~0.030% to make Ti
Scope.Preferably 0.006~0.028% scope.
N：0.0036~0.0075%
N is to ensure that the TiN of necessary amount necessary element.Sufficient TiN amounts, weld part can not be obtained during less than 0.0036%
Degraded toughness.During more than 0.0075%, occurred to be dissolved again by TiN during Thermal Cycle, solid solution N is excessively generated, so that tough
Property is significantly deteriorated.Therefore, N amounts are set to 0.0036~0.0075%.Preferably 0.0037~0.0068% scope.
Ca：0.0005~0.0030%
Ca is and the element with the effect for improving toughness by S fixation.In order to play this effect, it is necessary to contain
More than 0.0005% Ca.However, contain effective also saturation even more than 0.0030%.Therefore, in the present invention, Ca is limited
For 0.0005~0.0030% scope.
O：Less than 0.0040%
O contains as inevitable impurity in steel, turns into oxide during solidification and separates out, drops the cleanliness factor of steel
It is low.Therefore, O is preferably reduced as much as possible in the present invention.Particularly when O content is more than 0.0040%, CaO systems field trash is thick
Change and decline base metal tenacity.Therefore, it is less than 0.0040% to make O.
In present invention, it is desirable to meet following formula (1).
0 ＜ (Ca- (0.18+130 × Ca) × O)/1.25/S≤0.8 (1)
Wherein, in formula (1), Ca, O, S are content (quality %).
Ca, O and S need to contain in a manner of meeting the relation of formula (1).Now, turn into and answering for MnS is precipitated with CaS
Close the form of sulfide.The complex sulfide plays function, therefore the tissue of welding heat affected zone as the core of ferrite transformation
It is micronized, thus the toughness of welding heat affected zone is improved.(Ca- (0.18+130 × Ca) × O)/1.25/S value is 0
When following, CaS does not separate out crystallization, therefore S is separated out in the form of MnS is single.In rollings of the MnS when steel plate manufactures elongation from
And cause base metal tenacity to reduce, and melted in the welding heat affected zone MnS of the main starting point as the present invention, therefore
Fine dispersion can not be realized.On the other hand, when (Ca- (0.18+130 × Ca) × O)/1.25/S value is more than 0.8, S quilts substantially
Ca is fixed, and the MnS to be worked as ferrite generation core is not separated out on CaS, therefore can not realize that sufficient toughness improves.
The preferred scope of (Ca- (0.18+130 × Ca) × O)/1.25/S value is 0.10~0.8%.
It is above the preferable basis composition in the present invention.But in order to further improve characteristic, can contain Nb,
One or more of Cu, Ni, Cr, Mo, W, V, B.
Nb：0.003~0.050%
Nb is separated out in the form of NbC in ferrite transformation or when reheating, and contributes to high intensity.Moreover, have
The effect for expanding Unhydrated cement in the rolling of austenitic area, contribute to the grain refined of ferrite and bainite, therefore , Dui Tough
The improvement of property is also effective.By playing the effect containing more than 0.003% Nb, thus containing be preferably set to sometimes 0.003% with
On.However, during more than 0.050% addition, thick NbC is separated out, and leads the reduction for causing Tough on the contrary, therefore containing preferably making it sometimes
The upper limit is 0.050%.More preferably 0.005~0.040% scope.
Cu、Ni、Cr、Mo、W
Cu, Ni, Cr, Mo, W are the element for the quenching degree for improving steel.The intensity after rolling is directly contributed to improve, and
It can be added for functions such as Ti Gao Tough, elevated temperature strength or weatherabilities.Their effect by containing more than 0.01% and
Play, therefore, containing in the case of, preferably more than 0.01%.But excessively contain sometimes, can become Tough, weldability
Difference, therefore, the upper limit for containing in the case of, preferably making Cu respectively be 0.5%, the Ni upper limit is 1.0%, the Cr upper limit is
0.5%th, the Mo upper limit be 0.5%, the W upper limit be 0.4%.
V：Less than 0.2%
V be by the form of the V (C, N) precipitation strength make the element that the intensity of steel improves, can in order to play the effect
To contain more than 0.001%.But during containing having more than 0.2%, Tough reductions can be made.Therefore, in the case of containing V, preferably
Less than 0.2% is set to, is more preferably set to 0.001~0.10% scope.
B：0.0003~0.0030%
B is with the element of the quenching degree of micro raising steel.In order to play the effect, more than 0.0003% can be contained.But
It is during containing having more than 0.0030%, to make the Tough of weld part reduce, therefore, in the case of containing B, being preferably set to
Less than 0.0030%.More preferably 0.0003~0.0026% scope.
In the present invention, in order that characteristic improves, can in mentioned component composition further one kind containing Mg, Zr, REM
More than.
Mg：0.0005~0.0050%
Mg is that have to disperse, to improve the element of the effect of toughness, to be added as needed on by oxide.Pass through
The effect can be played containing more than 0.0005%, therefore containing in the case of, is preferably set to more than 0.0005%.Even if
Content more than 0.0050% effect also can saturation, therefore, when adding Mg, preferably make addition be 0.0005~0.0050%.
Zr：0.001~0.020%
For Zr, oxide is formed in steel, it is scattered and with the group for making welding heat affected zone by its oxide
Miniaturization is knitted so as to improve the effect of toughness, the effect of the present invention will not be also damaged even if addition, therefore can be added as needed
Add.By the way that the effect can be played containing more than 0.001%, therefore containing in the case of, it is preferably set to more than 0.001%.
But excessively addition when effect saturation, and form thick field trash and make the degraded toughness of mother metal, therefore in the case of addition,
It is preferred that the upper limit for making addition is 0.020%.
REM：0.001~0.020%
REM forms oxide in steel, by its oxide it is scattered with make the tissue miniaturization of welding heat affected zone from
And the effect of toughness is improved, the effect of the present invention will not be also damaged even if addition, therefore can be added as needed on.By containing
More than 0.001% can play the effect, therefore containing in the case of, be preferably set to more than 0.001%.But when excessively adding
Effect saturation, and form thick field trash and make the degraded toughness of mother metal, therefore in the case of addition, preferably make addition
The upper limit be 0.020%.
In the present invention, separated out in order that Ca is crystallized in the form of CaS, it is necessary to reduction in advance and Ca combination before Ca additions
The strong O of power amount, the remaining oxygen amount before preferably Ca additions are less than 0.0050%., can be with as the method for reducing remaining oxygen amount
Take the method for strengthening and deaerating or putting into deoxidier etc..
Surplus beyond mentioned component is Fe and inevitable impurity.
2. thickness of slab skin section and central portion Tough and texture
In the present invention, for what is developed along the horizontal direction (direction in the face of steel plate) such as rolling direction or rolling vertical direction
For crackle, in order to obtain improving Fig. 1 of crack propagation stop performance fracture morphology, suitably provide in thickness of slab skin section
And the aggregation degree in central portion Tough and RD//(100) face.
First, Mu Cai Tough are well the premises for suppressing the development of crackle.For the steel plate of the present invention, as thickness of slab
Skin section and the toughness of central portion are, it is specified that the Charpy fracture transition temperature vTrs of thickness of slab skin section and thickness of slab central portion is -50 DEG C
Below.
In addition, by making the texture in RD//(100) face flourishing, make cleavage surface (cleavage plane) relative to crackle master
Direction is obliquely gathered, the effect that the stress by producing brittle crack front end caused by small crackle branch relaxes, fragility
Crack propagation Stopping Ability improves.For the nearest thickness of slab for being used for the ship hull plates such as container ship and bulk carrier more than 50mm
Thick-wall materials, Kca (- 10 DEG C) >=6000N/mm as target is obtained in terms of safety of structure is ensured3/2Brittle crack
, it is necessary to which the aggregation degree for making RD//(110) face in thickness of slab skin section is more than 1.3, preferably 1.6 in the case of propagating Stopping Ability
More than, and make RD//(110) face in thickness of slab central portion aggregation degree be more than 1.8, preferably more than 2.0.Therefore, it is of the invention
In, the aggregation degree in RD//(110) face in thickness of slab skin section is more than 1.3, preferably more than 1.6, the RD/ in thickness of slab central portion/
(110) aggregation degree in face is more than 1.8, preferably more than 2.0.
On the other hand, due to being knitted when the aggregation degree in the RD/ in thickness of slab skin section or thickness of slab central portion/(110) face is more than 4.0
Structure is excessively flourishing, the clear and definite branch of brittle crack and not fine crackle branch occurs, it is difficult to play by brittle crack front end
The brittle-cracking propagation Stopping Ability that stress alleviation effects are brought.Therefore, the aggregation degree in the RD/ in thickness of slab skin section/(110) face
And the aggregation degree in the RD/ in thickness of slab central portion/(110) face is both preferably less than 4.0.
Here, the aggregation degree in the RD/ of thickness of slab skin section or thickness of slab central portion/(110) face refers to following numerical value.First, from
The sample of thickness of slab skin section or thickness of slab central portion collection thickness of slab 1mm, pair face parallel with plate face carry out mechanical lapping/electrolysis and ground
Mill, thus, prepare the test film of X-ray diffraction.It should be noted that in the case of thickness of slab skin section, pair connect with most surface
Near face is ground.Using the test film, using the X-ray diffraction device using Mo radiographic sources, implement X-ray diffraction survey
It is fixed, (200), (110) and (211) pole figure is obtained, is calculated by Bunge methods by resulting pole figure and tries to achieve three-dimensional crystals orientation
Density function.Then, by resulting three-dimensional crystals orientation density function, recorded by Bunge, in ψ2=0 °~90 ° with 5 °
In total 19 sectional view in interval, the three-dimensional crystals that accumulation (110) face reaches parallel orientation relative to rolling direction are orientated
The value of density function, obtains accumulated value, will obtained from the number of the accumulated value divided by the orientation of above-mentioned accumulation value be referred to as RD//
(110) aggregation degree in face.
In addition to above-mentioned Mu Cai Tough and texture regulation, preferably thickness of slab skin section and the Charpy of thickness of slab central portion
The aggregation degree in Tough values and RD//(110) face meets following (2) formulas.
vTrs(top layer)+1.9×vTrs(1/2t)-6×IRD//(110) [top layer]-84×IRD//(110)[1/2t]≤-350···(2)
Wherein, in formula (2),
vTrs(top layer)：The Charpy fracture transition temperature (DEG C) of thickness of slab skin section
vTrs(1/2t)：The Charpy fracture transition temperature (DEG C) of thickness of slab central portion
IRD//(110) [top layer]：The aggregation degree in the RD/ of thickness of slab skin section/(110) face
IRD//(110)[1/2t]：The aggregation degree in the RD/ of thickness of slab central portion/(110) face
By meeting above-mentioned (2) formula, more excellent brittle-cracking propagation Stopping Ability can be obtained.
3. metal structure
In the present invention, metal structure is based on ferrite.Here, in the present invention, metal structure is based on ferrite
The area percentage for referring to ferritic phase is overall more than 60%.As long as bainite in surplus, martensite (including island martensite
Body), total area percentage of pearlite etc. is then subjected to for less than 40%.
In tissue based on ferrite, the rolling condition in being rolled according to common austenitic area is obtained with iron element
In the case of metal structure of the body for main body, although obtaining the Tough as mesh mark, from austenite to ferrite after rolling
Transformation time is fully present during phase transformation, and therefore, resulting texture becomes unordered, can not realize on the thickness of slab top layer as target
In portion the aggregation degree in RD//(110) face be more than 1.3, preferably more than 1.6, the aggregation degree in RD//(110) face of thickness of slab central portion
For more than 1.8, preferably more than 2.0.Therefore, as described later, by designing rolling condition, even the group based on ferrite
Knit, can also obtain the aggregation degree in RD/ in thickness of slab skin section/(110) face for more than 1.3, preferably more than 1.6, thickness of slab central portion
RD//(110) face aggregation degree be more than 1.8, preferably more than 2.0.
4. manufacturing condition
Hereinafter, the preferable manufacturing condition in the present invention is illustrated.
As manufacturing condition, the preferably heating-up temperature of regulation steel former material, hot-rolled condition, cooling condition etc..Especially with regard to
Hot rolling, preferably except total accumulation reduction ratio in austenite recrystallization temperature area and austenite non-recrystallization humidity province
Outside, the situation in austenite recrystallization temperature area is also in thickness of slab central portion and in austenite non-recrystallization humidity province
Situation respectively provides accumulation reduction ratio and the average reduction ratio of every 1 passage.By these regulations, for the thickness of slab of steel plate
The aggregation degree in Charpy fracture transition temperature vTrs and RD//(110) face in skin section and thickness of slab central portion, can be obtained
Desired characteristic.
First, the molten steel of above-mentioned composition is subjected to melting by converter etc., steel former material (steel billet) is made by continuous casting etc..
Then, after steel former material preferably being heated into 900~1150 DEG C of temperature, hot rolling is carried out.Good good Tough is arrived to be terrible
Property, the crystallization particle diameter for reduce heating-up temperature, reducing before rolling is effective.But when heating-up temperature is less than 900 DEG C, it is impossible to fully
Ensure the time of the rolling in progress austenite recrystallization temperature area.In addition, during more than 1150 DEG C, austenite crystal becomes thick, no
Only Dao Zhi Tough are reduced, and oxidational losses is notable, and yield rate reduces.Therefore, heating-up temperature is preferably 900~1150 DEG C.From
From the viewpoint of Tough, the scope of preferred heating-up temperature is 1000~1100 DEG C.
Generally, the situation of the metal structure based on ferrite is being obtained by implementing common austenitic area rolling
Under, although obtaining the Tough as mesh mark, transformation time is fully present when after rolling from austenite to ferrite transformation, because
This, resulting texture becomes unordered.Therefore, it can not be realized using the rolling of common austenitic area and the plate of target is used as in the present invention
In thick skin section the aggregation degree in RD//(110) face be more than 1.3, preferably more than 1.6, RD//(110) face in thickness of slab central portion
Aggregation degree be more than 1.8, preferably more than 2.0.Therefore, in the present invention, the regulation hot-rolled condition is preferably as follows, thus, i.e.,
It is the tissue based on ferrite to make, can also obtain the aggregation degree in RD/ in thickness of slab skin section/(110) face for more than 1.3,
It is preferred that the aggregation degree in the RD/ of more than 1.6, thickness of slab central portion/(110) face is more than 1.8, preferably more than 2.0.
For hot rolling, the thickness of slab central portion that carries out preferred first is in the state of austenite recrystallization temperature area
Accumulation reduction ratio is more than 20% and rolling of the average reduction ratio of every 1 passage below 5.0%.By making the accumulation pressure
Lower rate is more than 20%, austenite grain refined, and also grain refined , Tough are improved the metal structure finally given.On the other hand, pass through
The average reduction ratio for making every 1 passage in the temperature range is less than 5.0%, can particularly drawing near top layer in steel
Enter strain, thus, it is possible to which the aggregation degree for making RD//(110) face in thickness of slab skin section is more than 1.3, preferably more than 1.6, enter
And thickness of slab skin section grain refined, it can obtain thickness of slab skin section Tough and improve effect.
Then, preferably carry out accumulating in the state of the temperature of thickness of slab central portion is in austenite non-recrystallization humidity province
The rolling that reduction ratio more than 40% and the average reduction ratio of every 1 passage are more than 7.0%.By making in the temperature range
It is more than 40% to accumulate reduction ratio, and the texture of thickness of slab central portion can be made fully flourishing, moreover, by making the flat of every 1 passage
Equal reduction ratio is more than 7.0%, can make thickness of slab central portion RD//(110) face aggregation degree for more than 1.8, preferably 2.0 with
On.
In addition, as making above-mentioned austenite recrystallization temperature area and austenite non-recrystallization humidity province altogether total
Body, accumulation reduction ratio is preferably more than 65%.By making overall accumulation reduction ratio be more than 65%, it can be ensured that for tissue
For sufficiently drafts , Tough and aggregation degree can realize desired value.
, can be by carrying out to this for austenite recrystallization temperature area and austenite non-recrystallization humidity province
The preliminary experiment that the steel of composition composition assigns the heat/processing course for changing condition is held.
It should be noted that the end temp of hot rolling is not particularly limited.But from the viewpoint of rolling efficiency, preferably exist
Austenite non-recrystallization terminates it in humidity province.
Steel plate after terminating for rolling, is preferably cooled to less than 600 DEG C with 4.0 DEG C/more than s cooling velocity.Pass through
It is 4.0 DEG C/more than s to make cooling velocity, can obtain sappy structure without making tissue coarsening, can obtain as target
Excellent toughness.When cooling velocity is less than 4.0 DEG C/s, coarsening is organized, can not be obtained as Mu Biao Tough.By making cooling
It is less than 600 DEG C to stop temperature, can avoid the progress of recrystallization, cooling by hot rolling and afterwards, be able to maintain that gained
The desired texture arrived.When cooling stops temperature higher than 600 DEG C, being recrystallized after cooling stops can also be carried out, it is impossible to
To desired texture.It should be noted that above-mentioned cooling velocity and cooling stop the temperature that temperature is set to the thickness of slab central portion of steel plate
Degree.The temperature of thickness of slab central portion is tried to achieve by thickness of slab, surface temperature and cooling condition etc. by simulating calculating etc..It is for example, logical
Cross and use calculus of finite differences, calculate the Temperature Distribution in thickness of slab direction, obtain the temperature of the thickness of slab central portion of steel plate.
Steel plate after terminating for cooling, can also implement temper.By implementing to be tempered, steel can be further improved
Ban Tough.Temperature is set to A in terms of steel plate mean temperatureC1Implement temper below point, thereby, it is possible to do not damage
By rolling, cooling down resulting desired tissue.In the present invention, A is obtained by following formulaC1Point (DEG C).
AC1Point=751-26.6C+17.6Si-11.6Mn-169Al-23Cu-23Ni+24.1Cr+22.5Mo+23 3Nb-
39.7V-5.7Ti-895B
In above-mentioned formula, each element symbol is content (quality %) in steel, and 0 is set to when not containing.
The mean temperature of steel plate is also same with the temperature of thickness of slab central portion, by thickness of slab, surface temperature and cooling condition etc.
Obtained by simulating calculating etc..
Embodiment
The molten steel (steel mark A~R) of each composition shown in table 1 is subjected to melting by converter, steel is made by continuous metal cast process
Former material (steel billet thickness 250mm), is hot-rolled down to 50~80mm of thickness of slab, then, is cooled down, and obtain No.1~30 supplies examination steel.For
A part, also implement tempering after the cooling period.Hot-rolled condition, cooling condition and tempered condition are shown in table 2.
Table 2
Note 1：Underscore represents outside the scope of the present invention.
Note 2：" recrystallization γ areas accumulation reduction ratio " refers to thickness of slab central portion in the state in austenite recrystallization warm area
Under accumulation reduction ratio.
Note 3：" the average reduction ratio in recrystallization γ areas " refers to thickness of slab central portion in austenite recrystallization temperature area
The average reduction ratio of every 1 passage under state.
Note 4：" reduction ratio is accumulated in non-recrystallization γ areas " refers to thickness of slab central portion in austenite non-recrystallization humidity province
In the state of accumulation reduction ratio.
Note 5：" the average reduction ratio in non-recrystallization γ areas " refers to thickness of slab central portion in austenite non-recrystallization temperature
The average reduction ratio of every 1 passage in the state of area.
Note 6：" overall accumulation reduction ratio " refers to merge thickness of slab central portion in the state in austenite recrystallization warm area
And the overall accumulation reduction ratio of the state in austenite non-recrystallization humidity province.
For resulting steel plate, at a right angle by 1/4 length direction with test film and the rolling direction of thickness of slab
Mode cuts Φ 14 JIS14A test films, carries out tension test, measure yield point (YS), tensile strength (TS).
Mirror ultrafinish is carried out to the thickness of slab section parallel with mill length direction of gained steel plate, then shown by optics
The metal structure that micro mirror observation shows through corrosion.
In addition, in order to evaluate toughness value, by thickness of slab skin section and thickness of slab central portion (below, sometimes by thickness of slab central portion
It is designated as 1/2t portions) JIS4 impact test pieces are cut in a manner of the direction of the major axis of test film is parallel with rolling direction, carry out
Charpy-type test, fracture transition temperature (vTrs) is obtained respectively.Here, the impact test piece of thickness of slab skin section is made away from surface
Nearest face is the test film of the depth away from surface of steel plate 1mm.
Then, in order to evaluate brittle-cracking propagation stopping characteristics, carrying out standard ESSO experiments, (temperature-gradient type ESSO is tried
Test), obtain the Kca values (Kca (- 10 DEG C)) at -10 DEG C.
In order to evaluate Large Heat Input Welding characteristic, to implementing retaining wall on slope (20 ° of bevel angle) for examination steel plate, use is commercially available
Cryogenic steel pneumoelectric welding wire, joint is made by Large Heat Input Welding (300~750kJ/cm) electrogas arc welding (EGW).So
Afterwards, for the surface and back side 1mm positions in thickness of slab direction, the Charpy-type test piece of breach is introduced using melt run portion, is asked
Go out test temperature for the absorption energy at -20 DEG C：VE-20 DEG C (3 average value), thus evaluate HAZ toughness.
In addition, the aggregation degree in RD//(110) face of thickness of slab skin section and thickness of slab central portion is obtained as follows.First, from thickness of slab
Skin section or thickness of slab central portion cut thickness of slab 1mm sample, and carrying out mechanical lapping/electrolysis by pair face parallel with plate face grinds
Mill, prepare the test film of X-ray diffraction.It should be noted that in the case of thickness of slab skin section, grind close to most surface
Face.Using the test film, using the X-ray diffraction device using Mo radiographic sources, implement X-ray diffraction measure, obtain (200),
(110) and (211) pole figure, calculated by Bunge methods from resulting pole figure and obtain three-dimensional crystals orientation density function.Connect
, by resulting three-dimensional crystals orientation density function, recorded by Bunge, in ψ2=0 °~90 ° total 19 with 5 ° of intervals
Sectional view in, accumulation (110) face reach relative to rolling direction parallel orientation three-dimensional crystals orientation density function value,
Accumulated value is obtained, value obtained from the number of the accumulated value divided by the orientation of above-mentioned accumulation is referred to as gathering for RD//(110) face
Degree.
These result of the tests are shown in table 3.Thickness of slab skin section and thickness of slab central portion Tough value (fracture transition temperatures
VTrs) and texture within the scope of the invention for examination steel plate (manufacture No.1~13) in the case of, Kca (- 10 DEG C) is
6000N/mm3/2More than, show excellent brittle-cracking propagation Stopping Ability.Moreover, the absorption energy of welding heat affected zone：vE-
20 DEG C of excellent values for showing more than 125J.In addition, the Xia of skin section and thickness of slab central portion Bi Tough value (fracture transition temperature
Degree) and RD//(110) aggregation degree meet (2) formula for examination steel plate (manufacture numbering 1~13), be unsatisfactory for (2) formula for examination
Steel plate (manufacture numbering 14) is compared, and obtains high Kca (- 10 DEG C) value.In addition, these metals for examination steel plate (manufacture No.1~14)
Tissue is based on ferrite.
On the other hand, for composition composition or manufacturing condition outside the scope of the present invention, steel plate Tough or texture is discontented with
The foot present invention's is defined for examination steel plate (manufacture numbering 15~30), and Kca (- 10 DEG C) value is less than 6000N/mm3/2, and/or weldering
Connect the absorption energy of heat affected zone：VE-20 DEG C is less than 100J, therefore poorer than example of the present invention.
Table 3
Note 1：Underscore is represented outside the scope of the invention.
Note 2：(2) formula vTrs(top layer)+1.9×vTrs(1/2t)-6×IRD//(110) [top layer]-84×IRD//(110)[1/2t]≤-350
vTrs(top layer)：The fracture transition temperature (DEG C) of thickness of slab skin section,
vTrs(1/2t)：The fracture transition temperature (DEG C) of thickness of slab central portion (t/2),
IRD//(110) [top layer]：The RD/ of thickness of slab skin section/(110) aggregation degree,
IRD//(110)[1/2t]：The RD/ of thickness of slab central portion (t/2)/(110) aggregation degree
Note 3：1/2t portions represent thickness of slab central portion.
Label declaration
1 standard ESSO test films
2 breach
3 crackles
4 front end geometries
5 mother metals
Claims (7)
- A kind of 1. Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics, it is characterised in that steel group C is calculated as into quality %：0.03~0.15%, Si：Less than 0.50%, Mn：1.0~2.0%, P：Less than 0.030%, S： 0.0005~0.0040%, Al：0.005~0.10%, Ti：0.004~0.030%, N：0.0036~0.0075%, Ca： 0.0005~0.0030%, O：Less than 0.0040%, also, Ca, O, S each content meet following formula (1), surplus is by Fe and can not The impurity avoided is formed, and based on ferrite, the aggregation degree with RD//(110) face in thickness of slab skin section is metal structure More than 1.3, the aggregation degree in the RD/ in thickness of slab central portion/(110) face is more than 1.8 texture, thickness of slab skin section and thickness of slab center The Charpy fracture transition temperature vTrs in portion is less than -50 DEG C, and metal structure refers to the area of ferritic phase using ferrite as main body Percentage is overall more than 60%,0 ＜ (Ca- (0.18+130 × Ca) × O)/1.25/S≤0.8 ... (1)Wherein, in formula (1), Ca, O, S are weight/mass percentage composition.
- 2. the Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics according to claim 1, Characterized in that, the aggregation degree in thickness of slab skin section and the Charpy fracture transition temperature and RD/ of thickness of slab central portion/(110) face is expired Foot states (2) formula,vTrs(top layer)+1.9×vTrs(1/2t)-6×IRD//(110) [top layer]-84×IRD//(110)[1/2t]≤-350…(2)Wherein, in formula (2),vTrs(top layer)：The Charpy fracture transition temperature of thickness of slab skin section, its unit for DEG C,vTrs(1/2t)：Thickness of slab central portion t/2 Charpy fracture transition temperature, its unit for DEG C,IRD//(110) [top layer]：The aggregation degree in the RD/ of thickness of slab skin section/(110) face,IRD//(110)[1/2t]：The aggregation degree in thickness of slab central portion t/2 RD//(110) face,It should be noted that t is thickness of slab, its unit is mm.
- 3. the Large Heat Input Welding high strength steel of excellent in brittle-cracking propagation stopping characteristics according to claim 1 or 2 Plate, it is characterised in that steel composition further contains Nb in terms of quality %：0.003~0.050%, Cu：Less than 0.5%, Ni： Less than 1.0%, Cr：Less than 0.5%, Mo：Less than 0.5%, W：Less than 0.4%, V：Less than 0.2%, B：0.0003~ More than one or both of 0.0030%.
- 4. the Large Heat Input Welding high strength steel of excellent in brittle-cracking propagation stopping characteristics according to claim 1 or 2 Plate, it is characterised in that steel composition further contains Mg in terms of quality %：0.0005~0.0050%, Zr：0.001~ 0.020%th, REM：More than one or both of 0.001~0.020%.
- 5. the Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics according to claim 3, Characterized in that, steel composition further contains Mg in terms of quality %：0.0005~0.0050%, Zr：0.001~0.020%, REM：More than one or both of 0.001~0.020%.
- 6. a kind of manufacture method of the Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics, its feature It is, the steel former material with the composition any one of claim 1,3,4 or 5 is heated to 900~1150 DEG C of temperature, Implement the overall accumulation reduction ratio that merges austenite recrystallization temperature area and austenite non-recrystallization humidity province for 65% with Go up, the accumulation reduction ratio in the state of thickness of slab central portion is in austenite recrystallization temperature area is more than 20% and every 1 The average reduction ratio of passage is less than 5.0% rolling, then, carries out being in austenite non-recrystallization temperature in thickness of slab central portion The rolling that accumulation reduction ratio in the state of area is more than 40% and the average reduction ratio of every 1 passage is more than 7.0%, Then, on the basis of the temperature of thickness of slab central portion, less than 600 DEG C are cooled to 4.0 DEG C/more than s cooling velocity.
- 7. the Large Heat Input Welding high-strength steel sheet of excellent in brittle-cracking propagation stopping characteristics according to claim 6 Manufacture method, it is characterised in that after being cooled to below 600 DEG C, further have and be tempered to AC1The process of the following temperature of point.
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| WO2017145651A1 (en) * | 2016-02-24 | 2017-08-31 | Ｊｆｅスチール株式会社 | High strength ultra-thick steel plate having excellent brittle crack propagation stopping characteristics and manufaturing method of same |
| JP6274375B1 (en) * | 2016-08-09 | 2018-02-07 | Ｊｆｅスチール株式会社 | High strength thick steel plate and manufacturing method thereof |
| WO2018030171A1 (en) * | 2016-08-09 | 2018-02-15 | Ｊｆｅスチール株式会社 | High-strength thick steel plate and production method therefor |
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| CN113166830B (en) * | 2018-12-07 | 2023-04-18 | 杰富意钢铁株式会社 | Steel sheet and method for producing same |
| CN110343957B (en) * | 2019-07-22 | 2021-06-15 | 盐城市联鑫钢铁有限公司 | High-strength fire-resistant corrosion-resistant steel for construction and manufacturing method thereof |
| JP7444339B1 (en) | 2022-06-01 | 2024-03-06 | Ｊｆｅスチール株式会社 | Steel plate for high heat input welding and its manufacturing method |
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| JPH07100814A (en) | 1993-10-04 | 1995-04-18 | Sekisui Chem Co Ltd | Manufacture of cement molded item |
| JP3467767B2 (en) | 1998-03-13 | 2003-11-17 | Ｊｆｅスチール株式会社 | Steel with excellent brittle crack arrestability and method of manufacturing the same |
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| JP5432548B2 (en) * | 2009-03-04 | 2014-03-05 | 株式会社神戸製鋼所 | Thick steel plate with excellent brittle crack propagation stop properties |
| JP5216530B2 (en) * | 2008-10-29 | 2013-06-19 | 株式会社神戸製鋼所 | Thick steel plate with excellent brittle crack propagation stop properties |
| JP5432565B2 (en) * | 2009-04-01 | 2014-03-05 | 株式会社神戸製鋼所 | Thick steel plate with excellent brittle crack propagation stopping properties and fatigue crack growth inhibition properties |
| JP5284015B2 (en) * | 2008-09-04 | 2013-09-11 | 株式会社神戸製鋼所 | Thick steel plate with excellent brittle crack propagation stop properties |
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| JP5434145B2 (en) * | 2009-03-04 | 2014-03-05 | Ｊｆｅスチール株式会社 | Structural high-strength thick steel plate with excellent brittle crack propagation stopping characteristics and method for producing the same |
| JP5342902B2 (en) * | 2009-03-11 | 2013-11-13 | 株式会社神戸製鋼所 | Steel material excellent in toughness and base metal fatigue characteristics of weld heat-affected zone and its manufacturing method |
| WO2010134220A1 (en) * | 2009-05-22 | 2010-11-25 | Ｊｆｅスチール株式会社 | Steel material for high heat input welding |
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| CN102373371B (en) * | 2010-08-25 | 2013-10-30 | 宝山钢铁股份有限公司 | Method for raising large heat input weldability of thick steel plate |
| JP5304924B2 (en) * | 2011-12-27 | 2013-10-02 | Ｊｆｅスチール株式会社 | Structural high-strength thick steel plate with excellent brittle crack propagation stopping characteristics and method for producing the same |
| CN102605247B (en) * | 2012-03-09 | 2014-06-04 | 宝山钢铁股份有限公司 | High-heat-input welding thick steel plate and manufacturing method thereof |
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2013
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- 2013-10-24 CN CN201380075179.0A patent/CN105102651B/en active Active
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| BR112015021658A2 (en) | 2017-07-18 |
| JPWO2014155439A1 (en) | 2017-02-16 |
| WO2014155439A1 (en) | 2014-10-02 |
| JP5598617B1 (en) | 2014-10-01 |
| TWI500774B (en) | 2015-09-21 |
| TW201502282A (en) | 2015-01-16 |
| KR20170117235A (en) | 2017-10-20 |
| CN105102651A (en) | 2015-11-25 |
| KR20150119281A (en) | 2015-10-23 |
| PH12015501681A1 (en) | 2015-10-19 |
| KR101984531B1 (en) | 2019-05-31 |
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