CN108130479A - The excellent plate thickness of long brittle-cracking propagation stopping characteristics is the steel plate and its manufacturing method of more than 50mm - Google Patents
The excellent plate thickness of long brittle-cracking propagation stopping characteristics is the steel plate and its manufacturing method of more than 50mm Download PDFInfo
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- CN108130479A CN108130479A CN201810089072.6A CN201810089072A CN108130479A CN 108130479 A CN108130479 A CN 108130479A CN 201810089072 A CN201810089072 A CN 201810089072A CN 108130479 A CN108130479 A CN 108130479A
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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
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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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
- 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
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
- C21D8/0426—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
- 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
- C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
- C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
- C21D8/0463—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment following 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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- 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
-
- 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
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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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
-
- 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
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
-
- 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
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—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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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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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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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
- G01N2203/006—Crack, flaws, fracture or rupture
- G01N2203/0062—Crack or flaws
- G01N2203/0066—Propagation of crack
Abstract
The present invention provides the steel plate and its manufacturing method that a kind of excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics is more than 50mm, and the steel plate is as follows：In the plate thickness central portion, it is more than 1.5 in the X-ray intensity ratio in (211) face of the rolling surface at the position at least 20% region of plate thickness (t) or (100) face, is more than 1.3 in the X-ray intensity ratio in 1/4~1/10 region as the plate thickness (t) or (110) face of the rolling surface in 3/4~9/10 region as the plate thickness (t)；The front end geometry for carrying out the long brittle-cracking propagation stop in the plate thickness direction section of plane of fracture when large size ESSO is tested is, stopping cracking length in 20% region that the width of plate thickness central portion is plate thickness (t), relative to the maximum cracking length in 1/4~1/10 or 3/4~9/10 region as plate thickness (t) as plate thickness (t) since surface of steel plate, at least shortened in the direction of advance of the long brittle crack with the length of plate thickness (t), and form recessed recessed portion.
Description
The application is the 201280007816.6 (applying date of patent application：On 2 7th, 2012, invention and created name：Length is crisp
Property crack propagation stop performance excellent plate thickness be more than 50mm steel plate and its manufacturing method and the long brittle crack of evaluation
Propagate Stopping Ability method and experimental rig) divisional application.
Technical field
The present invention relates to one kind to be suitable for Large Container Ship (Mega-container carrier), bulk freighter (bulk
) etc. carrier the excellent plate thickness of brittle-cracking propagation stopping characteristics (brittle crack arrestability) is 50mm
Above steel plate and its manufacturing method.In addition, further relate to a kind of evaluation and the comparable long brittle crack (long of real ship
Brittle crack) propagate Stopping Ability method and experimental rig.
Background technology
In order to improve delivered payload capability (carrying capacity), the efficiency of loading and unloading (cargo handling
Efficiency) etc., container ship, bulk freighter become the structure for forming large-scale upper opening portion (upper aperture).Cause
This, is in order to ensure the rigidity (rigidity) and longitudinal strength (longitudinal strength) of hull, in these ships,
Heavy wall is formed in particular for ship hull plate (outer plate of vessel ' s body) is made.
In recent years, container ship gradually maximizes, in 6000~20000TEU (twenty-foot equivalent
Unit in argosy), the plate thickness of ship hull plate becomes more than 50mm, causes due to plate thickness effect (Thickness effect)
Fracture toughness (fracture toughness) reduces, and thermal weld stress (welding heat input) also further increases
Greatly, so the fracture toughness of weld part (welded part) has the trend further reduced.It should be explained that TEU (Twenty-
Foot Equivalent Unit) it represents to be converted into the number of the container of 20 feet of length, to show the loading of container ship
The index of ability.
It is relatively thin less than 50mm for the plate thickness of steel plate used in ship (ships), pipeline steel tube (linepipe)
Steel can realize crystal grain refinement using TMCP methods (Thermomechanical controlled processing), carry
High/low temperature toughness (low-temperature toughness), assigns excellent brittle-cracking propagation stopping characteristics.
As the method for improving brittle-cracking propagation stopping characteristics, it is proposed that do not increasing cost of alloy (alloy cost)
In the case of make steel surface section (surface part) tissue micronization technology.For example, in patent document 1,
Eye is in brittle-cracking propagation, in shear lip (shear-lips) (plastic deformation area that steel surface section generates
(plastic deformation area)) it is effective for improving brittle-cracking propagation stopping characteristics, it discloses by making shearing
The crystal grain miniaturization of lip portion propagates energy (propagation energy) to absorb possessed by the brittle crack of propagation
Method.
After carrying out hot rolling to steel plate, (controlled cooling) is cooled down by control be cooled to surface part
Ar3Transformation temperature cools down hereinafter, stopping control thereafter, makes more than surface part backheat to transformation temperature, which is repeated 1 time
More than, therebetween, by being depressed to steel, so as to make its phase transformation or processing recrystallization (recrystallization repeatedly
Due to deformation), surface part is made to generate ultra tiny ferritic structure (ferrite structure) or shellfish
Family name's body tissue (bainite structure).
Following content is disclosed in patent document 2：In the microscopic structure based on ferrite-pearlite (pearlite)
(microstructure) in steel, if forming two surface elements, institute with the layer with more than 50% ferritic structure
State ferritic structure have circle equivalent average grain diameter be less than 5 μm, the ferrite that aspect ratio (aspect ratio) is more than 2
Grain, and then, make every time maximum depression rate (maximum rolling reduction) in finish rolling for 12% hereinafter, from
And inhibit the recrystallization phenomenon (recrystallization phenomenon) of part, and inhibit the fluctuation of ferrite grain size,
The effect that excellent brittle-cracking propagation stopping characteristics improve can then be obtained.
In patent document 3, as bearing, the resistance to brittle-cracking propagation after plastic deformation (plastic deformation) is special
Property excellent steel, disclose as the method described in following (a)~(d) manufacture to be formed with subgrain (sub- in crystal grain
Grain fine ferrite) is the steel of Main Tissues.
Using following condition (a)~(d), the temperature control of the complexity such as cooling and the backheat on steel plate surface layer is not needed to
(temperature control), so that it may improve the brittle-cracking propagation stopping characteristics after bearing plastic deformation, that is, (a) ensures
The rolling condition of fine ferrite crystal grain；(b) more than 5% part of steel plate thickness is made to generate the rolling of fine ferrite structure
Condition；(c) make fine ferrite development set tissue, and using thermal energy (thermal energy) make by process (rolling) and
The dislocation (dislocation) of importing is reconfigured, and forms the rolling condition of subgrain；(d) inhibit formed fine ferrite crystalline substance
The coarsening cooling condition of grain and fine subgrain.
In addition, as the technological thought (technological thought) different from Patent Documents 1 to 3, patent document
Following content has been recorded in 4：It is put down gathering tissue (texture) by development in the plane of fracture upper edge of steel with plate thickness direction
Capable direction generates separation and by making the stress mitigation of brittle crack front end (brittle crack tip) resistance to crisp to improve
In the method for property crack propagation characteristic, by controlled rolling, make (110) face X-ray intensity ratio (X-ray intensity
Ratio it is) more than 2, and the coarse grain that equivalent circle diameter is made to be 20 μm or more is less than 10%.
A kind of steel plate is disclosed in patent document 5, which is characterized in that as the crisp of welded-joint (welded joint)
The property excellent steel for welded structures of crack propagation Stopping Ability, the X ray surface intensity in (100) face of the rolling surface inside plate thickness
Than having more than 1.5, and describe following content：Tissue is gathered by development, so as to make crack propagation direction (crack
Propagation direction) relative to the side vertical with mechanical load direction (stress loading direction)
To change, brittle crack is guided from welded-joint to base material side, improves the brittle-cracking propagation Stopping Ability as connector.
In addition, a kind of steel plate is disclosed in patent document 6, which is characterized in that (211) face of the rolling surface of plate thickness central portion
X-ray intensity ratio have more than 1.3, and (100) face X-ray intensity ratio of the rolling surface of plate thickness 1/4 have 1.5 with
On, (100) face X-ray intensity ratio of the rolling surface of plate surface section has more than 1.5, and describe following content：Pass through development
Gather tissue, it, should so as to generate crack (crack) near the brittle crack front end charged into via T connectors etc. from surface of steel plate
Crack plays a role as crack propagation resistance, improves for the brittle-cracking propagation of brittle crack propagated in plate thickness direction
Stopping Ability.
On the other hand, it is believed that in Ship Structure (hull structure), just in case generate brittle break from weld part
When (brittle failure), it is also desirable to the propagation of brittle crack be made to stop preventing hull from detaching.Japan Shipbuilding Research Association
(The Shipbuilding Research Association of Japan) the 147th committee makes plate thickness less than 50mm
The brittle-cracking propagation behavior of ship plate weld part has carried out experimental study.
147th committee in weld part to forcing the propagation path of the brittle crack of generation, dissemination to be tested
Research, if as a result, the fracture toughness (fracture toughness) of weld part is ensured to a certain extent, due to weldering
The influence of residual stress (welding residual stress) is connect, brittle crack deviates mostly from weld part to base material side, but
Also it confirmed the example that multiple brittle cracks are propagated along weld part.This, which is suggested, cannot conclude no non-plastic fracture along welding
The possibility that portion's straight trip is propagated.
However, the welding application identical with the welding that the 147th committee applies is built in steel plate of the plate thickness less than 50mm
Ship have largely put into real achievement as service (actual service) with not having any problems, and toughness is good
The ability that good steel plate mother metal (E grades of steel of shipbuilding etc.) is considered stopping brittle crack is abundant, therefore in ship's classification rule (Rules
And Guidance for the survey and construction of steel ships) etc. in do not require shipbuilding
With the brittle-cracking propagation stopping characteristics in welded steel portion.
Patent document 1：Japanese Unexamined Patent Publication 4-141517 bulletins
Patent document 2：Japanese Unexamined Patent Publication 2002-256375 bulletins
Patent document 3：No. 3467767 bulletins of Japanese Patent Publication No.
Patent document 4：No. 3548349 bulletins of Japanese Patent Publication No.
Patent document 5：Japanese Unexamined Patent Publication 6-207241 bulletins
Patent document 6：Japanese Unexamined Patent Publication 2008-214652 bulletins
Non-patent literature 1：Mountain pass et al.：" exploitation of super-container vessel (Mega-container carrier)-
The practical application-of novel high-strength pole steel plate (new high strength heavy gauge steel plate) ", day
This ship ocean engineering meeting bulletin, 3, (2005), P70.
Invention content
However, the plate thickness for being more than recently the Large Container Ship light plate of 6000TEU is more than 50mm, due to plate thickness effect
Fracture toughness is caused to reduce, and thermal weld stress also further increases, so the fracture toughness of weld part has further drop
Low trend.
Recently, it experimentally shows：In such heavy wall high heat-input welding point (large heat input
Welded joint of heavy gauge steel plate) in, the brittle crack generated from weld part is not to base material lateral deviation
Liftoff straight trip and growing up (long and large), even if in framework material (or also referred to as armature.stiffeners)
Deng steel plate mother metal portion in also do not stop (non-patent literature 1), in the Ship Structure of the steel plate for the plate thickness for applying more than 50mm
Safety ensure aspect become serious problems.In addition, the experiment that the safety as hull as evaluation ensures, there is large size
ESSO is tested, but result of the test changes due tos the difference of evaluation method, limitation of experimental rig etc., is existed and the comparable length of real ship
Brittle-cracking propagation Stopping Ability not necessarily obtains evaluation this problem.
The steel plate that above patent document 1~6 is recorded does not remember the brittle-cracking propagation stopping characteristics after growing up
It carries, the subject explicitly pointed out in non-patent literature 1 can not be solved.In addition, it is not directed in the technology that Patent Documents 1 to 6 are recorded
It evaluates and is recorded with the method for the comparable long brittle-cracking propagation stopping characteristics of real ship, experimental rig, can not be solved and real ship
The subject of comparable safety evaluatio.
Therefore, even if steel plate and its weld part the purpose of the present invention is to provide a kind of plate thickness in more than 50mm generate
During non-plastic fracture, the brittle crack for growing up can be also made before extensive rupture (catastrophic fracture) is reached
The steel plate and its manufacturing method of stopping.In addition to this, its purpose is to provide a kind of evaluations and the real comparable long brittleness of ship to split
Line propagates the method and experimental rig of Stopping Ability.It should be explained that so-called long brittle crack refers to from adjacent its herein
The length that its steel plate is charged into is the brittle crack of more than 1m.
The inventors of the present invention to the multiple steel plates for changing chemical composition and rolling condition have studied set tissue morphology with it is crisp
Property crack propagation stop performance (sometimes referred to as crack arrest characteristic (arrestability)) relationship, also, have studied crack arrest characteristic
The distribution of (by toughness, set tissue effect) in plate thickness direction, which stops long brittle-cracking propagation phenomenon generation, to be influenced.Separately
Outside, between passing through distance changing wing plate front end (distance between tips of tab plates) or physical burden
The dynamic FEM of distance (distance between loading points) is analyzed and can be simulated comparable with real ship between point
The evaluation method of the large-scale ESSO experiments of long brittle-cracking propagation characteristic, experimental rig are studied.
Its result it is found that in control chemical composition and rolling condition, and provide the toughness impacted to crack arrest characteristic and
Gather tissue in the distribution in plate thickness direction, long brittle-cracking propagation Stopping Ability significantly improves, and can make to think difficult always before this
With the long brittle crack propagated in thick and heavy steel plate or its weld part of stopping in no stress reflexion and the comparable condition of real ship
Under stop in steel plate.And then dynamic FEM analyses as a result, by making distance and physical burden point spacing between wing plate front end
From for defined value, the evaluation method tested so as to the large size ESSO comparable with real ship understood without stress reflexion is tested
Device.It should be explained that steel plate of the thickness less than 50mm can make long brittleness in existing steel plate (such as shipbuilding E grades of steel etc.)
Crack stop, so the present invention is using the steel plate of more than thickness 50mm as object.
The present invention is based on above-mentioned opinions to make further research, i.e., the present invention relates to the following contents：
(1) a kind of excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics is the steel plate of more than 50mm, and feature exists
In in the front end geometry of the long brittle-cracking propagation stop in plate thickness direction section, in the plate thickness (t) of plate thickness central portion
Stopping crack length in 20% width regions, relative to since surface of steel plate become plate thickness (t) 1/4~1/10 or
The maximum crack length in 3/4~9/10 region of plate thickness (t), in the direction of advance of above-mentioned long brittle crack, at least with plate
The length of thick (t) shortens, and forms recessed recessed portion.
(2) steel plate that the excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics as described in (1) is more than 50mm,
It is characterized in that, in above-mentioned plate thickness central portion, in (211) face of the rolling surface at the position at least 20% region of plate thickness (t)
Or the X-ray intensity ratio in (100) face is more than 1.5,
1/4~1/10 region of above-mentioned plate thickness (t) or the rolling surface in 3/4~9/10 region of above-mentioned plate thickness (t)
(110) face X-ray intensity ratio be more than 1.3.
(3) thickness that the excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics as described in (1) or (2) is more than 50mm
Steel plate, which is characterized in that in above-mentioned plate thickness central portion, the rolling surface at the position at least 20% region of plate thickness (t)
(211) face X-ray intensity compares X(211)Compare X with (100) face X-ray intensity(100)And the utilization 2mmV type notch shocks of same area
It tests obtained fracture transition critical-temperature vTrs (DEG C) and meets formula：VTrs-12X(100)- 22X(211)≤ (T-75)/0.64
[T is steel plate for temperature (DEG C)],
Also, in 1/4~1/10 region as above-mentioned plate thickness (t) or 3/4~9/10 as above-mentioned plate thickness (t)
Region rolling surface (110) face X-ray intensity ratio be more than 1.3.
(4) the excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics as described in any one of (1)~(3) is 50mm
Above steel plate, which is characterized in that in terms of quality %, steel composition is as follows：
Contain C：Less than 0.15%, Si：Less than 0.60%, Mn：0.80~1.80%, S：0.001~0.05%,
Containing selected from Ti：0.005~0.050% and Nb：It is at least one kind of in 0.001~0.1%,
And then containing selected from Cu：Less than 2.0%, V：Less than 0.2%, Ni：Less than 2.0%, Cr：Less than 0.6%, Mo：
Less than 0.6%, W：Less than 0.5%, B：Less than 0.0050%, Zr：It is at least one kind of in less than 0.5%,
Surplus is made of Fe and inevitable impurity.
(5) a kind of excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics is the manufacturer of the steel plate of more than 50mm
Method, which is characterized in that will there is the temperature that 900~1350 DEG C are heated into the Steel material being grouped as described in (4),
Then, it in the temperature region of 1000~850 DEG C of surface of steel plate temperature, is rolled with more than 10% accumulation reduction ratio
After system, surface of steel plate temperature is formed as 900~600 DEG C and the shape of 50~150 DEG C higher than surface of steel plate temperature of steel plate internal temperature
State,
Thereafter, the surface of steel plate temperature at the end of 1 more than 7% percentage pass reduction, more than 50% reduction ratio of accumulation, rolling
Hot rolling is carried out under conditions of being 800~550 DEG C.
(6) the excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics as described in (5) is the steel plate of more than 50mm
Manufacturing method, which is characterized in that after terminating hot rolling, be further cooled to 400 DEG C with the cooling velocity of 5 DEG C/more than s.
(7) evaluation method of the long brittle-cracking propagation Stopping Ability of a kind of steel or works, which is characterized in that make
The long brittle crack for being more than 1m for crack propagation length is evaluated, confirms with the large-scale experiment piece of more than test film width 2m
Propagation Stopping Ability experiment in, test leaf length or install test film experimental rig wing plate front end between distance for experiment
2.8 times or more of piece width.
(8) evaluation method of the long brittle-cracking propagation Stopping Ability of the steel as described in (7) or works, feature
It is, distance is further 4.1 times or more of test film width between the physical burden point of experimental rig.
(9) a kind of experimental rig for evaluating long brittle-cracking propagation Stopping Ability, which is characterized in that using test film wide
It spends the large-scale experiment piece for more than 2m and stops evaluating, confirm the propagation for the long brittle crack for being more than 1m to crackle spread length
In the experimental rig of performance, distance is 2.8 times or more of test film width between the wing plate front end for the experimental rig for installing test film.
(10) experimental rig of the long brittle-cracking propagation Stopping Ability of evaluation as described in (9), which is characterized in that experiment
Distance is further 4.1 times or more of test film width between the physical burden point of device.
Stop in accordance with the invention it is possible to assign excellent brittle-cracking propagation to the steel plate that plate thickness (t) is more than 50mm
Performance can make the long brittle crack in the heavyweight material of more than plate thickness 50mm difficult before this in no stress reflexion
(stress reflection) with real ship it is comparable under the conditions of it is lower stop, it is industrially exceedingly useful.
Description of the drawings
Fig. 1 is in the plate thickness direction section for the steel plate for showing schematically that plate thickness (t) according to the present invention is more than 50mm
Long brittle-cracking propagation stop front end geometry figure.
Fig. 2 is the figure for the size shape for representing large-scale ESSO (large-scale duplex ESSO) test film.
Fig. 3 A represent to study the ginseng of influence that stress reflexion generates the evaluation of long brittle-cracking propagation stopping characteristics
Dynamic FEM analysis models (dynamic finite element method in numberization model (parametric model)
analysis model)。
Fig. 3 B represent to study the load of influence that stress reflexion generates the evaluation of long brittle-cracking propagation stopping characteristics
Dynamic FEM analysis models when distance is 10m between heavy load point.
Fig. 3 C represent to study the load of influence that stress reflexion generates the evaluation of long brittle-cracking propagation stopping characteristics
Dynamic FEM analysis models when distance is 5m between heavy load point.
Fig. 4 is to represent experimental condition (away from experiment bit end as the analysis result that the model for dynamic analysis using Fig. 3 obtains
The distance in portion) to dynamic stress amplification coefficient (dynamic stress intensity factor) generate influence figure.
Specific embodiment
The front end geometry of the long brittle-cracking propagation stop in the section of plate thickness direction is provided in the present invention.Below to this
The restriction reason of invention illustrates.
Show schematically steel plate 1 of the plate thickness (t) according to the present invention for more than 50mm in the section of plate thickness direction in Fig. 1
Long brittle crack 2 propagation stop front end geometry (long brittle crack stop position 3).
In the present invention, the front end geometry for making long brittle-cracking propagation stop is following shape：In plate thickness central portion
The long brittle crack stop position of 20% width regions of plate thickness (t) with since surface of steel plate as plate thickness (t) 1/4~
1/10 and as plate thickness (t) 3/4~9/10 width regions long brittle crack stop position position between, most short interval
(it is following at least shortened in the direction of advance of long brittle crack with the depth a of the length of plate thickness (t) for depth a) have it is recessed
Summary U-shaped recessed portion.
In order to improve the crack arrest characteristic of steel plate entirety, the plate thickness central portion in the plate thickness direction section of steel plate, plate thickness are improved
(t) at least 20% width regions ta(region of its upper and lower more than 10% width of 1/2 position including plate thickness (t))
Crack arrest characteristic.It should be explained that from the viewpoint of limited rolling load (rolling load), preferably make raising crack arrest characteristic
Region taIt is less than 50%.
If improve the peak width t near the plate thickness center of crack arrest characteristicaLess than the 20% of plate thickness, then plate thickness (t)
1/4~1/10 nearby (1/4 position and 1/10 position including plate thickness (t), the region between 1/4 position and 1/10 position)
With 3/4~9/10 of plate thickness (t) nearby (3/4 position and 9/10 position including plate thickness (t), 3/4 position and 9/10 position it
Between region) rupture driving force do not reduce fully, and 1/4~1/10 of plate thickness (t) nearby and plate thickness (t) 3/4
Near~9/10, crackle stoppingly is not propagated, so at least 20%.
In plate thickness direction section, compared with other regions, the stopping of the long brittle crack in the excellent region of crack arrest characteristic is grown
Spend short, and recessed recessed portion formed in its direction of advance, thus make the front end geometry of long brittle-cracking propagation stop into
At least 20% region of plate thickness (t) to make plate thickness central portion recessed in the direction of advance of long brittle crack is substantially in U
The recessed portion of shape.
In addition, with regard to substantially be in U-shaped recessed portion shape for, in order to reduce the 1/4~1/10 of plate thickness (t) nearby and
Rupture driving force near the 3/4~9/10 of plate thickness (t), the brittle crack in 20% region of the plate thickness of plate thickness central portion stop
Only length with 3/4~9/10 region of 1/4~1/10 and plate thickness (t) in plate thickness (t) brittle crack stop length compared with,
It needs at least with the length of short slab thick (t) to shorten, so in the direction of advance of long brittle crack, forms the depth a of recessed portion
Recessed shape at least with the equal length of plate thickness (t).
Depth a is provided as follows：The 1/4~1/10 of plate thickness (t) in Fig. 1 and the 3/4~9/10 of plate thickness (t) region
The long brittle crack stop position of expression (also referred to as maximum crack length) the line at a right angle with plate thickness direction, and by plate
Thick central portion represents the line parallel with plate thickness direction of 20% peak width of plate thickness and long brittle-cracking propagation stop position
Intersection point the line at a right angle with plate thickness direction interval in, the length at most short interval.
In order to observe thickness be more than 50mm steel plate non-plastic fracture section in, plate thickness (t) 1/4~1/10 or
Longest crack propagation portion (near the A points and A ' point of Fig. 1), attached in plate thickness central portion in 3/4~9/10 region of person's plate thickness (t)
Closely in the comparison in these regions, the shape that long brittle-cracking propagation stop position is described on plate thickness direction is in the present invention
It is provided.It should be explained that relative to plate thickness (t) 1/2 position become it is symmetrical above and below on plate thickness direction away from surface of steel plate
For plate thickness (t) 1/4~1/10 region and be plate thickness (t) 3/4~9/10 region crack arrest characteristic, long brittle-cracking propagation
The front end geometry of stop is roughly the same.
The front end geometry of above-mentioned long brittle-cracking propagation stop is can to use large size ESSO test films 4 shown in Fig. 2
Section confirmed.Large-scale ESSO test films 4 are as described below：Breadboard 6 is with helping limp (Crack-running plate)
5 by CO2Weld part 8 engages, and is helping 5 upper edge of limp and CO2The setting pneumoelectric weld part in direction at a right angle of weld part 8
(electrogas arc weld) 7, from brittle crack (not shown) edge that physical notches (mechanical notch) 9 generate
It pneumoelectric weld part 7 to propagate, and examination is charged at a right angle with the physical burden direction (loading direction) of breadboard 6
Test plate 6.Physical burden direction is the rolling direction (rolling direction) of arrow R.D. in figure.In the present invention, length is crisp
Property crack propagation stop performance refers to the propagation distance (propagation of the brittle crack used until breadboard 6 is protruded into
Length) long large-scale ESSO test films 4, using between the wing plate front end not influenced in the same manner as practical ship by stress reflexion
The characteristic that the sufficiently long testing machine of distance is evaluated between distance, physical burden point.So-called stress reflexion refers to herein, by crisp
Property crackle generate, propagate and generate compression stress wave (compressive stress wave) experiment wing plate portion (tab
Plate of testing machine) etc. reflection.If generating the stress reflexion, the stress wave compressed returns to brittleness
Crack propagation portion, so brittle crack becomes easily to stop.In the works such as practical ship, the size of works relative to
Brittle crack is sufficiently large, so not generating (or being difficult to generate) stress reflexion.Therefore, the propagation halt characteristic of long brittle crack needs
It will be using distance sufficiently long testing machine is evaluated between distance, physical burden point between wing plate front end.
Steel plate according to the present invention is preferably provided with following set tissues.
X ray in (211) face of the rolling surface at least 20% region of the plate thickness of plate thickness central portion or (100) face is strong
Than being more than 1.5, the X in plate thickness 1/4t~1/10t portions or (110) face of the rolling surface in plate thickness 3/4t~9/10t portions is penetrated degree
Line intensity ratio is more than 1.3.
If (211) face of the rolling surface near plate thickness center or the X-ray intensity ratio in (100) face are more than 1.5,
Generate fine sub- crack (subcrack), brittle-cracking propagation face (brittle crack propagating surface)
Bumps become larger, crack propagation resistance (crack propagation resistance) increase, brittle-cracking propagation stop it is tough
Property greatly improves.If X-ray intensity ratio is less than 1.5, the effect is confirmed.According to the above, by the plate of plate thickness central portion
(211) face of rolling surface of 20% thick area above or the X-ray intensity ratio in (100) face are defined to more than 1.5.
On the other hand, if the X-ray intensity ratio in (110) face of the rolling surface in plate thickness 1/4t~1/10t portions is less than
1.3, then stop length and plate thickness 1/4t~1/10t areas in the brittle crack in more than 20% region of the plate thickness of plate thickness central portion
The brittle crack in domain stops length and compares, and is not short to more than plate thickness degree, without causing near plate thickness 1/4t~1/10t portions
The reduction of the rupture driving force in (the longest crack propagation portion near the A points and A ' point of Fig. 1).It as a result, will be in plate thickness 1/4t~1/
The X-ray intensity ratio in (110) face of the rolling surface in 10t portions is defined to more than 1.3.Above-mentioned regulation is in plate thickness 3/4t~9/10t portions
Also it is identical.
And then stop toughness in the brittle-cracking propagation at a temperature of to improve steel plate, preferably satisfy following formula.
VTrs-12X(100)- 22X(211)≤ (T-75)/0.64
(wherein, X in formula(211)It represents in plate thickness central portion, the rolling surface of at least 20% region portion of plate thickness (t)
(211) face X-ray intensity ratio, X(100)Represent (100) face X-ray intensity ratio of same area, vTrs (DEG C) represents same area
The fracture transition critical-temperature obtained from 2mmV type nick break tests, T represent steel plate for temperature (DEG C))
This parameter type is to stop using for temperature to ensure to gather the brittle-cracking propagation at object position in tissue
Only toughness provides the parameter type of steel plate toughness according to set tissue with vTrs, in order to which the Charpy fracture for making the object position turns
Become critical-temperature vTrs to be less than for temperature, the regulation vTrs in a manner of meeting above formula.It should be explained that as described above, in order to carry
High brittle-cracking propagation stops toughness, needs that the X-ray intensity ratio in (211) face or (100) face is made to be more than 1.5, the two it
In, (211) face set tissue is big to the help for improving brittle-cracking propagation stopping toughness, so X in increase formula(211)Relative to
X(100)Coefficient.
Steel plate with above-mentioned characteristic it is preferred as described below with manufacturing condition into being grouped as.% is matter in explanation
Measure %.
[into being grouped as]
C：Less than 0.15%
C is in order to ensure intensity and required.From the viewpoint of being ensured intensity, it is 0.02% preferably to make lower limit.But
If C amounts are more than 0.15%, welding heat affected zone (HAZ) toughness reduces, so C amounts are defined to less than 0.15%.It should say
Bright, in order to which (211) face and the set tissue in (100) face is made further to develop, preferred range is less than 0.03%.
Si：Less than 0.60%
Si is to rise effective element to intensity.The effect in order to obtain, preferably comprises more than 0.01%.If Si amounts are super
0.60% is crossed, then welding heat affected zone (HAZ) toughness is made significantly to deteriorate, so Si amounts are defined to less than 0.60%.
Mn：0.80~1.80%
Mn is effective element to high intensity, and from the viewpoint of being ensured intensity, it is 0.80% to make lower limit.But such as
Fruit Mn amounts are more than 1.80%, then base metal tenacity is it is possible that deterioration.Therefore, make the range that Mn is 0.80~1.80%.It should be explained that
Preferred range is 1.00~1.70%.
S：Less than 0.001~0.05%
In the present invention, it needs that brittle crack leading edge (leading edge of brittle crack) is made to generate crack
(fracture parallel with surface of steel plate), so needing containing more than 0.001% S.But S forms non-metallic inclusion and makes
Ductility, toughness deterioration, so being limited to less than 0.05%.
Ti：0.005~0.050%, Nb：1 kind in 0.001~0.1% or 2 kinds
Ti has the following effects that, that is, by the precipitate for forming carbide (carbide), nitride (nitride)
(precipitate), so as to the life of the austenite grain (austenite grain) of the heating period when inhibiting steel plate manufacture
It is long, contribute to crystal grain refinement, and also inhibit the crystalline substance of welding heat affected zone (welded heat-affected zone) (HAZ)
Grain coarsening, improves HAZ toughness.These effects in order to obtain, need containing more than 0.005%.On the other hand, it is excessive to contain
Toughness can be deteriorated, so using 0.050% as the upper limit.
Nb is also effective to precipitation strength (precipitation strengthening) and the raising of toughness.In addition, also press down
The recrystallization (recrystallization) of austenite processed, promotes the effect generated by aftermentioned rolling condition.In order to obtain this
A little effects need more than 0.001% addition, but if addition more than 0.1%, then spiculation occurs in quenching structure, and toughness has bad
The trend of change, so using 0.1% as the upper limit.
Selected from Cu：Less than 2.0%, V：Less than 0.2%, Ni：Less than 2.0%, Cr：Less than 0.6%, Mo：Less than 0.6%,
W：Less than 0.5%, B：Less than 0.0050%, Zr：It is at least one kind of in less than 0.5%.
Cu：Less than 2.0%
Cu may be used primarily for precipitation strength.Its effect in order to obtain, preferably comprises more than 0.05%.If addition is more than
2.0%, then precipitation strength is excessive and toughness deteriorates, so Cu amounts are preferably less than 2.0% range.
V：Less than 0.2%
V is solution strengthening (solid solution strengthening) and the utilizable ingredient of precipitation strength.For
It obtains its effect, preferably comprises more than 0.001%.It is if serious to damage base metal tenacity and weldering containing the V for having more than 0.2%
Connecing property, so V amounts are preferably less than 0.2% range.
Ni：Less than 2.0%
Ni improves intensity and toughness, and effective to Cu during rolling is prevented to be broken when adding Cu.It is imitated in order to obtain
Fruit preferably comprises more than 0.05%.But due to costliness, and even if being excessively added, effect also saturation, it is advantageous to
It is added in less than 2.0% range.
Cr：Less than 0.6%
Cr has the effect for improving intensity.Its effect in order to obtain, preferably comprises more than 0.01%.But if contain
Cr more than 0.6%, then toughness of welded zone deterioration, so Cr contents are preferably less than 0.6% range.
Mo：Less than 0.6%
Mo has the effect for improving room temperature and the intensity under high temperature.Its effect in order to obtain, preferably comprises more than 0.01%.
But if containing the Mo for having more than 0.6%, weldability deterioration, so content is preferably less than 0.6% range.
W：Less than 0.5%
W has the effect for improving elevated temperature strength.Its effect in order to obtain, preferably comprises more than 0.05%.But if contain
0.5% is had more than, then not only deteriorates toughness, but also is expensive, it is advantageous to contain W in the range below 0.5%.
B：Less than 0.0050%
B is precipitated in rolling in the form of BN, and the ferrite grain after rolling is made to attenuate.Its effect in order to obtain, preferably contains
Have more than 0.0010%.But if it exceeds 0.0050%, then toughness deteriorates, so being defined to less than 0.0050%.
Zr：Less than 0.5%
Zr is the element for the breaking property of resistance to plating for not only improving intensity but also improving zinc-plated material.Its effect in order to obtain, it is excellent
Choosing contains more than 0.03%.But if containing having more than 0.5%, toughness of welded zone deterioration, thus Zr contents preferably with
0.5% is the upper limit.
For steel according to the present invention in addition to mentioned component forms, surplus is Fe and inevitable impurity.It should be explained that
As inevitable impurity, P can be allowed：Less than 0.035%, Al：Less than 0.08%, N：Less than 0.012%, 0：0.05%
Below, Mg：Less than 0.01%, etc..
For manufacturing condition, heating temperature (heating temperature), hot-rolled condition (hot are preferably provided
Rolling condition), cooling condition (cooling condition).In the case of being not specified by explanation, temperature,
Cooling velocity is set as the average value in plate thickness direction.
[heating temperature]
Steel blank is heated to 900~1350 DEG C of temperature.It is the equal of progress material that heating temperature is set as 900 DEG C or more
Heating needed for matter and aftermentioned controlled rolling is set as 1350 DEG C hereinafter, being the then surface oxidation because if temperature is excessively high
(surface oxidation) significantly, and the coarsening of inevitable crystal grain.It should be explained that in order to improve toughness, preferably make
The upper limit is 1150 DEG C.
[hot-rolled condition]
In the temperature region of 1000~850 DEG C of surface of steel plate temperature, with more than 10% accumulation reduction ratio
(cumulative rolling reduction) is rolled.
By being rolled in the temperature region, so as to austenite grain (austenite grain) partial recrystallisation, institute
Become fine and uniform with tissue.
It should be explained that the rolling at a temperature of more than 1000 DEG C contributes to the growth of austenite grain, so for crystalline substance
Grain refinement is without preferred.On the other hand, if less than 850 DEG C, then completely into the non-recrystallized region of austenite, for crystal grain
Homogenization is without preferred.
Form 900~600 DEG C of surface of steel plate temperature and 50~150 DEG C higher than surface of steel plate temperature of steel plate internal temperature
After state, the surface of steel plate temperature at the end of 1 percentage pass reduction is more than 7%, accumulation reduction ratio is more than 50% and is rolled
Hot rolling is carried out under conditions of being 850~550 DEG C
By formed surface of steel plate temperature for 900~600 DEG C and steel plate internal temperature it is higher than surface of steel plate temperature by 50~
150 DEG C of state, so as to which surface is almost nearby almost to become the non-recrystallized region of austenite inside two phase regions and steel plate
(non-recrystallization region)。
If implement the rolling that 1 percentage pass reduction is more than 7% under this condition, in the relatively low steel plate of intensity
Portion preferentially imports rolling deformation (rolling strain), and set is imported in 20% region of at least plate thickness of plate thickness central portion
Tissue.By the process, so as to form set tissue in austenite grain.
That is, forming the basis of (211) face set tissue, the basis of (211) the face set tissue is to before brittle crack
The crack at end generates one kind in effective phase transformation set tissue (transformation texture).It should be explained that in order to
Will gather tissue import plate thickness central portion at least plate thickness 20% region, it is highly preferred that 1 percentage pass reduction can be 10% with
On.
Thereafter, it is 850~550 DEG C by being rolling to surface of steel plate temperature, so as to be rolled inside steel plate with two phase regions
System forms (100) face set tissue.
In order to which the effective level of crack generation that the integrated level for making above-mentioned set tissue reaches to brittle crack front end (integrates
More than 1.55 degree), it is more than 50% to need to accumulate reduction ratio.
[cooling condition]
After terminating hot rolling, 400 DEG C are cooled to the cooling velocity of 5 DEG C/more than s.
If until 400 DEG C of temperature region, cooled down, then promoted from (211) with the cooling velocity of 5 DEG C/more than s
Face is passed on for the set tissue of advantage by austenite set tissue, and brittle-cracking propagation stops toughness and improves.
If cooled down under these conditions, the X ray surface intensity in (211) face becomes stronger, further promotes sub-
The generation in crack, crackle easily stop.It should be explained that in above-mentioned cooling means, preferred the beginning of cooling temperature
(cooling start temperature) is 700 DEG C or more.
It should be explained that when the steel plate thickness of steel plate according to the present invention being made to be less than 50mm, certainly with excellent crisp
Property crack propagation characteristic.
[evaluation method, experimental rig]
In order to evaluate long brittle-cracking propagation stopping characteristics under the conditions of no stress reflexion and real ship are comparable, utilize
The influence of stress reflexion is evaluated in dynamic FEM analyses, determines between the wing plate front end of testing machine distance between distance, physical burden point.
Large-scale ESSO experiments chip size is as shown in Figure 2.
Dynamic FEM analysis models are shown in Fig. 3 A, Fig. 3 B, Fig. 3 C, show the result in Fig. 4.Fig. 3 A are for not having clearly
The parameter model of the condition of stress reflexion is for analyzing the 11 (thickness of experiment wing plate impacted to stress reflexion
The model of the influence of distance (2A of Fig. 3 A) between 200mm).Fig. 3 B are the distances of the physical burden point 10 for the testing machine that will be used
It is set as model during 10m, Fig. 3 C are the models when distance of the physical burden point 10 for the testing machine that will be used is set as 5m.
FEM analysis results are shown in Fig. 4.Fig. 4 be from rupture generate to be obtained during charging into breadboard propagate in splitting
The figure of the variation of dynamic stress amplification coefficient (the rupture driving force in brittle-cracking propagation) Kd of line.The result that × label represents
It is the situation of 2A=10000mm, is not cause the comparable with real ship of stress reflexion charging into breadboard until brittle crack
Under the conditions of result.Under conditions of 2A=1800~4300mm, stress reflexion is generated, it is possible to when breadboard is charged into confirmation
Dynamic stress amplification coefficient Kd be lower with as compared with the situation of the 2A=10000mm of the comparable condition of real ship.It refers to
Under conditions of 2A=1800~4300mm, compared with real ship condition, long brittle crack easily stops.It on the other hand, can be true
Although recognize under conditions of 2A=6800mm, it is believed that some reductions of dynamic stress amplification coefficient Kd, with the comparable condition of real ship
Compared to having almost no change.
As a result, if the ensuring that 2A is more than 6800mm, then the evaluation with the comparable condition of real ship can be carried out, if for example
Distance is the large-scale tensile test fixture shape of 10m between physical burden point shown in Fig. 3 B, then can fully carry out and real ship phase
When condition evaluation.It is represented in Fig. 4 using when distance between the physical burden point of the testing machine used is set as 5m and 10m
Analysis result obtained from model, but if stretched using the large-scale of distance 10m models between the physical burden point shown in Fig. 3 B
Test fixture shape implements large size ESSO experiments, then is regarded as the commenting under the conditions of comparable with real ship of no stress reflexion
Valency.
It is analyzed by above FEM, just there is no the long brittle-cracking propagation with real ship under the conditions of comparable of stress reflexion
For the evaluation method of Stopping Ability, distance is experiment between testing leaf length or installing the wing plate front end of the experimental rig of test film
2.8 times or more (≈ 6800mm/2400mm) of piece width, and then, distance is wide for test film between the physical burden point of experimental rig
4.1 times or more (≈ 10000mm/2400mm) of degree.
Similarly, stop in no stress reflexion and long brittle-cracking propagation of the real ship under the conditions of comparable as can be evaluated
The only experimental rig of performance, between the wing plate front end for the experimental rig for being equipped with test film distance for 2.8 times of test film width with
Upper (≈ 6800mm/2400mm), and then distance is 4.1 times or more (≈ of test film width between the physical burden point of experimental rig
10000mm/2400mm)。
Embodiment
Using the steel billet for being adjusted to the various chemical compositions shown in table 1, the condition manufacture steel plate according to table 2.It is right
Thus obtained each steel plate carries out the X ray in (211) face and (100) face of the central portion (high crack arrest characteristic domain) of plate thickness (t)
Intensity than measure, and study Charpy fracture transition critical-temperature (Ductile-brittle transition
temperature of Charpy impact test)vTrs.In addition, 1/8 (1/4 of plate thickness (t) of plate thickness (t) is carried out
The representation position in~1/10 region) (110) face X-ray intensity than measure.
Then, in order to evaluate long brittle-cracking propagation stopping characteristics, above-mentioned steel plate (the original thickness of plate thickness (t) is used
Degree), the large-scale ESSO test films of size shape shown in Fig. 2 are made, for experiment.Experiment is in stress 257N/mm2, temperature
Implement under conditions of -10 DEG C.Herein, 257N/mm2Stress be the yield strength 40kgf/mm being commonly used in hull2
The maximum allowable stress of grade steel plate, -10 DEG C of temperature are the design temperature of ship.Large-scale ESSO experiments utilize big shown in Fig. 3 B
Type tensile test fixture, under conditions of distance is 6800mm between wing plate front end, distance is 10000mm between physical burden point into
Row.
The result for implementing large size ESSO experiments is shown in table 3.In example of the present invention (No2,3,6,8,9,12,14), brittleness
Crackle stops in fillet weld seam portion, and in comparative example (No.1,4,5,7,10,11,13,15,16), brittle crack does not stop.
Table 1
Table 2
Table 3
Symbol description
1 steel plate
2 long brittle cracks
3 long brittle crack stop positions
4 large size ESSO test films
5 help limp
6 breadboards
7 pneumoelectric weld parts
8 CO2Weld part
9 physical notches
10 physical burden points
11 wing plates
Claims (3)
1. a kind of excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics is the steel plate of more than 50mm, which is characterized in that with
Quality % is counted, and steel composition is as follows：Contain C：Less than 0.15%, Si：Less than 0.60%, Mn：0.80~1.80%, S：0.001~
0.05%, and contain Ti：0.005~0.050%, Nb：0.001~0.1%, Ni：2.0% hereinafter, further contain selected from Cu：
Less than 2.0%, V：Less than 0.2%, Cr：Less than 0.6%, Mo：Less than 0.6%, W：Less than 0.5%, B：Less than 0.0050%,
Zr：At least one kind of in less than 0.5%, surplus is made of Fe and inevitable impurity；
In the plate thickness central portion, in (211) face or (100) of the rolling surface at the position at least 20% region of plate thickness (t)
The X-ray intensity ratio in face is more than 1.5,
In 1/4~1/10 region as the plate thickness (t) or 3/4~9/10 region as the plate thickness (t)
The X-ray intensity ratio in (110) face of rolling surface is more than 1.3；
Carry out the front end geometry of the long brittle-cracking propagation stop in the plate thickness direction section of plane of fracture when large size ESSO is tested
For the stopping cracking length in 20% region that the width of plate thickness central portion is plate thickness (t), relative to since surface of steel plate
1/4~1/10 as plate thickness (t) or the maximum cracking length in 3/4~9/10 region as plate thickness (t), in the length
At least shortened in the direction of advance of brittle crack with the length of plate thickness (t), and form recessed recessed portion.
2. the excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics according to claim 1 is the thick steel of more than 50mm
Plate, which is characterized in that in the plate thickness central portion, in (211) of the rolling surface at the position at least 20% region of plate thickness (t)
Face X-ray intensity compares X(211)Compare X with (100) face X-ray intensity(100)And the utilization 2mmV type nick break tests of same area
Obtained fracture transition critical-temperature vTrs (DEG C) meets formula：VTrs-12X(100)- 22X(211)≤ (T-75)/0.64,
In, T be steel plate for temperature (DEG C),
Also, in 1/4~1/10 region as the plate thickness (t) or 3/4~9/10 area as the plate thickness (t)
The X-ray intensity ratio in (110) face of the rolling surface in domain is more than 1.3.
3. a kind of excellent plate thickness (t) of long brittle-cracking propagation stopping characteristics is the manufacturing method of the steel plate of more than 50mm,
It is characterized in that, by with the temperature described in claim 1 for being heated into the Steel material being grouped as 900~1350 DEG C,
Then, it in the temperature region that surface of steel plate temperature is 1000~850 DEG C, is rolled with more than 10% accumulation reduction ratio
Afterwards, surface of steel plate temperature is formed as 900~600 DEG C and the state of 50~150 DEG C higher than surface of steel plate temperature of steel plate internal temperature,
Thereafter, the surface of steel plate temperature at the end of 1 percentage pass reduction is more than 10%, accumulation reduction ratio is more than 50%, is rolled
Spend be 800~550 DEG C under conditions of carry out hot rolling,
After terminating hot rolling, further 400 DEG C are cooled to the cooling velocity of 5 DEG C/more than s.
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| CN2012800078166A CN103348030A (en) | 2011-02-08 | 2012-02-07 | Thick steel plate of at least 50mm in thickness with superior long brittle fracture propagation stopping properties, manufacturing method for same, and method for evaluating long brittle fracture propagation stopping performance and test apparatus for same |
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| CN2012800078166A Pending CN103348030A (en) | 2011-02-08 | 2012-02-07 | Thick steel plate of at least 50mm in thickness with superior long brittle fracture propagation stopping properties, manufacturing method for same, and method for evaluating long brittle fracture propagation stopping performance and test apparatus for same |
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| TWI523953B (en) | 2016-03-01 |
| TW201250007A (en) | 2012-12-16 |
| KR101584235B1 (en) | 2016-01-11 |
| JP2014145131A (en) | 2014-08-14 |
| CN103348030A (en) | 2013-10-09 |
| KR20130114239A (en) | 2013-10-16 |
| WO2012108543A1 (en) | 2012-08-16 |
| JP2014052385A (en) | 2014-03-20 |
| JP5598485B2 (en) | 2014-10-01 |
| JP2012180590A (en) | 2012-09-20 |
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