CN109652733A - A kind of 690MPa grades of super-thick steel plate and its manufacturing method - Google Patents
A kind of 690MPa grades of super-thick steel plate and its manufacturing method Download PDFInfo
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- CN109652733A CN109652733A CN201910013990.5A CN201910013990A CN109652733A CN 109652733 A CN109652733 A CN 109652733A CN 201910013990 A CN201910013990 A CN 201910013990A CN 109652733 A CN109652733 A CN 109652733A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
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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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
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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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
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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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
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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
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/0081—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for slabs; for billets
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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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
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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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
- 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
Abstract
The invention discloses a kind of 690MPa grades of super-thick steel plate and its manufacturing method, the mass percentage content of chemical component are as follows: C:0.04-0.08%, Mn:5.2-6.0%, Si:0.1-0.4%, Mo:0.1-0.5%, Ni:0.2-0.6%, Cr:0.2-0.6%, Ti:0.01-0.05%, S :≤0.005%, P :≤0.010% and surplus Fe and impurity.The steel plate is using manganese as main alloy element, the additive amount of the expensive element such as nickel when reducing super-thick steel plate manufacture, to reduce cost of alloy.Using specific manufacturing process, make super-thick steel plate obtained has high intensity, high-ductility, the excellent center portion mechanical property of high tenacity and anti-lamellar tearing performance, can satisfy demand of the harsh Service Environment such as ocean engineering to high performance ultra-thick steel plate.
Description
Technical field
The present invention relates to a kind of super-thick steel plate and its manufacturing method, in particular to a kind of 690MPa grades of super-thick steel plate and its system
Make method.
Background technique
As the implementation of national marine development strategy and petroleum resources exploitation are gradually from land to deep-sea and polar region direction
Development, the requirement of performance and safety of structure to ocean platform are higher and higher.Ocean platform manufactures required steel towards height
Intensity and high tenacity direction are developed, and the demand of 690MPa grades of yield strength of the tough ocean platform slab of height is increasing.
Traditional ocean engineering is difficult to improve with the center portion mechanical property of 690MPa grades of special heavy plates.In order to which the performance for improving steel plate entirety is equal
It is even, the elements such as a large amount of Ni, Mo, Cr, Cu are usually added into, the total addition level of these elements is even more than 4%, therefore cost of alloy
It is very high.In addition, usually also needing the techniques such as repeated hardening in a manufacturing method, manufacture difficulty is big.In recent years in order to meet ocean
Raising of the engineering construction to materials demand, the exploitation of high intensity levels super-thick steel plate receive significant attention.
The Chinese invention patent of Patent No. 201510125485.1 discloses a kind of with superior low temperature impact flexibility
Low yield strength ratio high toughness thick steel plate and its manufacturing method contain 3.6- in the low yield strength ratio high toughness thick steel plate chemical component
5.5% Ni, it is with high costs.
Application No. is 201610026446.0 Chinese patent application, disclose a kind of ocean engineering high strength steel plate and its
Production method uses Nb, V microalloying method, but since the content that the harden ability such as Mn improve element is not high, steel plate is maximum thick
Degree not can exceed that 100mm.
From the point of view of developing material status, there are also to be hoisted for the performance of current high performance ocean engineering super-thick steel plate.
Summary of the invention
Goal of the invention: in order to overcome the drawbacks of the prior art, the present invention provides a kind of 690MPa grades of super-thick steel plate, the steel plate
With excellent center portion mechanical property, demand of the harsh Service Environment such as ocean engineering to high performance ultra-thick steel plate can satisfy.
It is a further object of the present invention to provide a kind of manufacturing methods of above-mentioned 690MPa grades of super-thick steel plate.
Technical solution: a kind of 690MPa grades of super-thick steel plate of the present invention, the mass percentage content of chemical component are as follows:
C:0.04-0.08%, Mn:5.2-6.0%, Si:0.1-0.4%, Mo:0.1-0.5%, Ni:0.2-0.6%, Cr:0.2-
0.6%, Ti:0.01-0.05%, S :≤0.005%, P :≤0.010% and surplus Fe and impurity.
Further, the steel plate with a thickness of 80-150mm.
Further, the microstructure of the steel plate has martensite and austenite；Wherein, the volume fraction of austenite is 4-
10%.
Further, the center portion mechanical property of the steel plate are as follows: yield strength is not less than 690MPa, and tensile strength is not less than
770MPa, elongation after fracture are not less than 14%, and -60 DEG C of Charpy pendulum impact test impact absorbing energy of V-type sample are not less than
80J。
Further, which is not less than 50% based on the contraction percentage of area that plate thickness direction stretches.
And a kind of manufacturing method of 690MPa grades of super-thick steel plates of the present invention, the technical solution of use include following step
It is rapid:
(1) converter smelting is carried out after desulfurizing iron processing, reduce S, P content to S≤0.005% in molten steel, P≤
0.010%；
(2) alloying of mass fraction needed for LF refining completes C, Mn, Si, Mo, Ni, Ti element carries out RH processing later,
Vacuum degree≤4mbar handles time >=20min；
(3) casting obtains slab, ratio >=4 of slab thickness and steel plate thickness；
(4) heating of plate blank, 1060-1140 DEG C of temperature, soaking time 40-90min；
(5) slab after heating is rolled, start rolling temperature≤1020 DEG C, finishing temperature >=930 DEG C, passage deformation quantity
>=10%；
(6) water cooling is carried out immediately to the steel plate after rolling, surface of steel plate red temperature≤360 DEG C after cooling are average cold
But 1-5 DEG C of rate/s；
(7) steel plate is reheated to 780-830 DEG C, soaking time 5-15min, water cooling to steel plate table by quenching heat treatment
Face red temperature≤110 DEG C temperature, average 2-8 DEG C of cooling rate/s；
(8) quenched steel plate is heated to 610-640 DEG C, soaking time 40-70min, steel after tempering by tempering heat treatment
Plate is air-cooled to room temperature.
The utility model has the advantages that steel plate of the invention using manganese as main alloy element, reduces the valuableness such as nickel when super-thick steel plate manufactures
The additive amount of element, to reduce cost of alloy.Using specific manufacturing process, keep having for super-thick steel plate obtained high-strength
Degree, high-ductility, the excellent center portion mechanical property of high tenacity and anti-lamellar tearing performance, can satisfy the harsh military service such as ocean engineering
Demand of the environment to high performance ultra-thick steel plate.
Detailed description of the invention
Fig. 1 is the transmission electron microscope microphoto of 1 light plate core structure of embodiment.
Specific embodiment
Chemical component of the invention, manufacturing process, tissue and performance etc. are illustrated with reference to embodiments.
In the Design of Chemical Composition of 690MPa grade super-thick steel plate of the invention, C can be significant by gap solution strengthening
Tissue intensity is improved, is important intensified element, while being also important austenite stabilizer element, but in order to guarantee that low temperature rushes
Toughness and weldability are hit, needs to control its additive amount in reduced levels.Mn can improve tissue intensity by displacement solution strengthening,
Stabilization of austenite can be also significantly improved simultaneously.The appropriate addition of C and Mn can significantly improve harden ability, reduce supercooling Ovshinsky
The phase transition temperature of body, and obtain high-intensitive martensitic structure.On the other hand, in mar-tempering process, the addition of C and Mn
Reduce temperature required for forming a certain amount of adverse transformation austenite.C and Mn are enriched in adverse transformation austenite, make it low
Stable structure can still be maintained under temperature, become the vital tissue for improving plasticity and toughness of the present invention.It should be pointed out that when this
When tempering temperature is lower than 600 DEG C in invention, when being especially tempered near 550 DEG C of temperature, it be easy to cause the crystalline substance of the elements such as Mn, P
Boundary's segregation simultaneously reduces toughness.Inventor fully considers the mechanism of action of C and Mn element in the present invention, it is determined that C 0.04-
0.08%, " manganese in the low-carbon " ingredient that Mn is 5.2-6.0% designs.
Si is deoxidant element in steelmaking process, and suitable Si is able to suppress the segregation of Mn and P and improves toughness.Si can also
Solution strengthening is enough generated, but when content is more than 0.3% can be substantially reduced toughness.The present invention controls Si in 0.1-0.4%.
Mo can be improved the intensity after the tempering of martensite, can also weaken the crystal boundary segregation of Mn in certain content range
So as to improve toughness.The present invention controls Mo content in 0.1-0.5%, does not dramatically increase cost while playing Mo effect.
Ni can stable austenite phase, improve harden ability, reduce ductile-brittle transition temperature, be improve low-temperature flexibility effective member
Element, in addition there are be conducive to improve weldability.But Ni is expensive, and the present invention controls Ni content in 0.2-0.6%, not significant
The beneficial effect of Ni element is given full play to while increasing cost.
Cr can generate apparent solution strengthening effect, be conducive to improve intensity, can improve corrosion resistance.But in the present invention
In the case where adding more Mn element, Cr too high levels are easy to form the carbide of Cr, Mn in grain boundaries in tempering, reduce brilliant
The obstruction of bound pair crack propagation causes plasticity and toughness to reduce.The present invention is by the content range control of Cr in the suitable of 0.2-0.6%
Suitable range.
Micro Ti is added in the present invention, the crystalline substance under high temperature can be hindered by the Second Phase Precipitation form of tiny disperse
Boundary's migration, to refine crystal grain and improve mechanical property, additional amount is controlled in the range of 0.01-0.05%.
The content of strict control P and S, in the case where the present invention has added moderate content Mn element, S is easily formed with Mn
MnS simultaneously reduces plasticity.P is easy crystal boundary resistance to crack extension ability to be reduced, to reduce toughness in crystal boundary segregation.The present invention claims S
≤ 0.005%, P≤0.010%.
Residue of the invention be Fe, however, in common manufacturing process can inevitably from raw material or around ring
Impurity is introduced in border.Due to these impurity will be obvious to those skilled in the art that so its title and content
It does not record specifically in this manual.
In manufacturing method of the present invention, after being handled by desulfurizing iron carry out converter smelting reduce S and P content to S≤
0.005%, P≤0.010%, and pass through enough condition of high vacuum degree (vacuum degree≤4mbar), long enough vacuum time (processing time
>=20min) RH processing to reduce the content of gaseous impurity element, and the addition of the alloys such as C, Mn, Si, Mo, Ni, Ti then passes through
LF refining is completed, and therefore, can be realized the metallurgical effect of high cleanliness.
Slab casting can obtain the slab of different dimensions by the way of continuous casting or molding+forging.Slab thickness
The case where≤320mm, can be obtained by continuous casting mode, high production efficiency；The slab (> 320mm) of bigger thickness can pass through
Molding+forging mode.In order to realize center portion mechanical property required for the present invention, enough total deformation quantity conducts of rolling are needed
Necessary condition.Ratio >=4 of slab thickness and steel plate thickness are required in the present invention, can guarantee to roll head office's variable >=75%.
When steel plate thickness is 80mm, required slab thickness >=320mm；When steel plate thickness is 150mm, required slab thickness >=
600mm.Tissue and performance required for slab obtained is obtained by rolling and heat treatment process.
Within the scope of present component, the Ac3 temperature of steel is not higher than 770 DEG C.It is formed when heating of plate blank is to 1060-1140 DEG C
High temperature austenitic body tissue, while the alloying elements such as C, Mn are homogenized by diffusion way.In slab center portion temperature close to surface temperature
During the soaking for spending and continuing heat preservation, entire slab realizes the homogenization of austenite, and equal temperature time 40-90min can guarantee
Elements diffusion is uniform.In 1140 DEG C and following temperature, the Second Phase Particle of Ti can play the role of that crystal grain is hindered to grow up.But temperature
Elements diffusion is excessively slow when degree is lower than 1060 DEG C, and it is too low that austenite homogenizes efficiency.
The present invention carries out recrystallization rolling at 930 DEG C or more to the slab after heating to refine crystal grain.Start rolling temperature≤
1020 DEG C of crystal grain growth rates that can be avoided after recrystallizing are too fast.Passage deformation quantity >=10% has after capable of making ausforming
There are enough distortion that can accumulate, to guarantee recrystallization softening effect.
After steel plate rolling, in order to avoid the recrystal grain refined after rolling deformation is excessively grown up, need to after rolling
Steel plate carries out water cooling immediately.Martensite transfor mation will also occur in Cooling Process.Since the present invention is added to enough Mn elements, horse
Family name's body changes critical cooling rate and is lower than 1 DEG C/s, can also obtain martensitic structure in the lower situation of cooling rate.In steel plate
In the biggish situation of thickness, center portion is cooling usually cooling considerably slower than surface, and ingredient design of the invention can guarantee in thickness
Martensite transfor mation also occurs for the center portion for the steel plate of 80-150mm.But cooling rate is excessively high to be easy to cause excessively high steel plate thermal stress, very
To causing steel plate to crack, therefore the present invention controls average cooling rate and is not higher than 5 DEG C/s.Cooling surface of steel plate returns red after rolling
At 360 DEG C and hereinafter, can be avoided apparent Element segregation occurs for temperature selection in cooling procedure, and inhibits coarse carbide
It is precipitated, while this temperature is also below the Ms (martensite start) point under present component.It is cold after the rolling that the present invention selects
But technique can provide suitable forerunner's tissue for subsequent heat treatment process.
The present invention carries out quenching+tempering heat treatment to steel plate.780-830 DEG C of hardening heat is higher than Ac3, and soaking obtains Austria
Family name's body tissue.Due to having carried out water cooling to steel plate after rolling, the shape of Element segregation and coarse carbide in cooling procedure is avoided
At, therefore Ovshinsky in-vivo element homogenization time greatly shortens.The soaking time of selective quenching heating of the present invention is 5-15min,
Guarantee austenite homogenization while can also effective refining grain size, be conducive to the raising of mechanical property of steel plate.Quenching
The selection of cooling rate is identical as the selection reason of cooling rate after rolling, controls in 2-8 DEG C/s.But the steel plate table of quenching
Face red temperature require at 110 DEG C and hereinafter, this temperature lower than the Mf point under present component, can
Ensure that steel plate integrally obtains high-intensitive quenched martensite tissue.
Tempering heat treatment is carried out to quenched steel plate.In 610-640 DEG C of tempering temperature, time of soaking time 40-70min
During fire, other than the obdurability matching for improving martensite, additionally it is possible to obtain the reverted austenite Ovshinsky that volume fraction is 4-10%
Body is in mainly film-form, is distributed between martensite lath.In drawing process, the austenite stabilizer elements such as C and Mn are in Ovshinsky
Enrichment in vivo, improves the stability of austenite, during being air-cooled to room temperature after tempering, or even the lower temperature the case where
Under, the stabilization of crystal structure can still be maintained in austenite, without martensite transfor mation.Steel plate is air-cooled after tempering, additionally it is possible to
The thermal stress of super-thick steel plate is reduced, plate quality is improved.
After present invention heat treatment, in steel plate whole thickness direction, martensite+austenite especially has been obtained in steel plate center portion
Tissue.During tensile deformation, martensitic matrix provides the yield strength of 690MPa or more, the martensite after tempering
Plasticity also improved.Austenite deformation early period and mid-term as it is a kind of it is soft mutually alleviate stress raisers, and in shape
The later period of change can occur martensite and generate invigoration effect.Therefore, the presence of austenite has delayed the germinating and extension of crackle,
Play the important function for improving tensile strength and elongation after fracture.During impact deformation, the presence of austenite is hindered
Crack propagation improves crack expansion power, to improve impact flexibility.Since the austenite in the present invention is with enough steady
It is qualitative, it still is able to play the beneficial effect of On Impact Toughness at -60 DEG C.The beneficial work of austenite structure in the present invention
With, the work of the technological parameter of manufacturing method, especially tempering heat treatment closely related with its volume fraction and enrichment of element degree
Skill parameter selection the most directly determines the property of austenite structure.
Specifically, the center portion mechanical property of steel plate of the present invention are as follows: yield strength is not less than 690MPa, and tensile strength is not less than
770MPa, elongation after fracture are not less than 14%, and -60 DEG C of Charpy pendulum impact test impact absorbing energy of V-type sample are not less than
80J。
The definition of mechanical performance index is according to standard GB/T228.1, GB/T229 and GB/T5313 in the present invention, due to this
The definition of a little technical indicators is explicitly, so not illustrating excessively in the present specification to those skilled in the art.
It should be pointed out that the present invention is while realizing excellent steel plate center portion mechanical property, steel plate thickness is other
The mechanical property of position equally reaches the mechanical property of center portion.Since the present invention is to the tissue and performance of each position of super-thick steel plate
Effective control is carried out, steel plate has the very high thickness direction contraction percentage of area, the section shrinkage stretched based on plate thickness direction
Rate is not less than 50%, and anti-lamellar tearing performance is very excellent.
In the following, being described further with the above-mentioned steel plate of specific embodiment and its manufacturing method.
Embodiment 1: a kind of 690MPa grade super-thick steel plate of center portion excellent in mechanical performance, with a thickness of 80mm, chemical component (contains
Amount is expressed as mass percent) it include: 0.06%C, 5.7%Mn, 0.22%Si, 0.35%Mo, 0.2%Ni, 0.31%Cr,
0.02%Ti, S≤0.005%, P≤0.010%, as the Fe of residue and other inevitable impurity elements.
The manufacturing method of above-mentioned steel plate is as follows:
Converter smelting is carried out after desulfurizing iron processing, reduces S, P content to S≤0.005% in molten steel, P≤0.010%；
The alloying of mass fraction needed for LF refining completes the elements such as C, Mn, Si, Mo, Ni, Ti carries out RH processing, vacuum degree later
3mbar handles time 23min, reduces the gaseous impurity constituent content in molten steel；It is obtained using continuous casting mode with a thickness of 320mm
Slab.Heating of plate blank is to 1140 DEG C of temperature, soaking time 60min；Slab after heating is rolled, start rolling temperature 1005
DEG C, 952 DEG C of finishing temperature, rolling mill screwdown regulation is 320mm-280mm-240mm-200mm-165mm-135mm-110mm-
90mm-80mm；Water cooling is carried out immediately to the steel plate after rolling, it is 350 DEG C of surface of steel plate red temperature after cooling, average cooling fast
3.1 DEG C/s of rate.Quenching+tempering heat treatment is carried out to steel plate.810 DEG C of hardening heat, soaking time 10min, water cooling to steel plate table
77 DEG C of temperature of face red temperature, average 2.9 DEG C/s of cooling rate；626 DEG C of tempering temperature, soaking time 55min, steel plate after tempering
It is air-cooled to room temperature.
Obtained steel plate tissue contains martensite and austenite, and the volume fraction of austenite is 6.5%.Fig. 1 show steel
The martensite being spaced apart and austenite can be observed in photo in the transmission electron microscope microphoto of plate core structure, wherein light color
The lath-like microstructure of contrast is martensite, and the film-form tissue of dark contrast is austenite.The yield strength of steel plate center portion
758MPa, tensile strength 842MPa, elongation after fracture 16%, -60 DEG C of Charpy pendulum impact test impact absorbing energy of V-type sample
135J.The thickness direction contraction percentage of area 63% of steel plate.
Embodiment 2: a kind of 690MPa grade super-thick steel plate of center portion excellent in mechanical performance, with a thickness of 80mm, chemical component (contains
Amount is expressed as mass percent) it include: 0.04%C, 5.2%Mn, 0.4%Si, 0.1%Mo, 0.6%Ni, 0.6%Cr,
0.01%Ti, S≤0.005%, P≤0.010%, as the Fe of residue and other inevitable impurity elements.
The manufacturing method of above-mentioned steel plate is as follows:
Converter smelting is carried out after desulfurizing iron processing, reduces S, P content to S≤0.005% in molten steel, P≤0.010%；
The alloying of mass fraction needed for LF refining completes the elements such as C, Mn, Si, Mo, Ni, Ti carries out RH processing, vacuum degree later
3mbar handles time 20min, reduces the gaseous impurity constituent content in molten steel；It is obtained using continuous casting mode with a thickness of 320mm
Slab.Heating of plate blank is to 1105 DEG C of temperature, soaking time 40min；Slab after heating is rolled, start rolling temperature 1001
DEG C, 930 DEG C of finishing temperature, rolling mill screwdown regulation is 320mm-280mm-240mm-200mm-165mm-135mm-110mm-
90mm-80mm；Water cooling is carried out immediately to the steel plate after rolling, it is 271 DEG C of surface of steel plate red temperature after cooling, average cooling fast
4.7 DEG C/s of rate.Quenching+tempering heat treatment is carried out to steel plate.830 DEG C of hardening heat, soaking time 5min, water cooling to surface of steel plate
51 DEG C of temperature of red temperature, average 4.2 DEG C/s of cooling rate；640 DEG C of tempering temperature, soaking time 40min, steel plate is empty after tempering
It is cooled to room temperature.
Obtained steel plate tissue contains martensite and austenite, and the volume fraction of austenite is 10%.Steel plate center portion is bent
Take intensity 741MPa, tensile strength 821MPa, elongation after fracture 17.5%, -60 DEG C of Charpy pendulum impact test impacts of V-type sample
Absorb energy 165J.The thickness direction contraction percentage of area 71% of steel plate.
Embodiment 3: a kind of 690MPa grade super-thick steel plate of center portion excellent in mechanical performance, with a thickness of 150mm, chemical component
(content is expressed as mass percent) includes: 0.08%C, 6.0%Mn, 0.1%Si, 0.5%Mo, 0.5%Ni, 0.2%Cr,
0.05%Ti, S≤0.005%, P≤0.010%, as the Fe of residue and other inevitable impurity elements.
The manufacturing method of above-mentioned steel plate is as follows:
Converter smelting is carried out after desulfurizing iron processing, reduces S, P content to S≤0.005% in molten steel, P≤0.010%；
The alloying of mass fraction needed for LF refining completes the elements such as C, Mn, Si, Mo, Ni, Ti carries out RH processing, vacuum degree later
3mbar handles time 26min, reduces the gaseous impurity constituent content in molten steel；Using forging method after molding obtain with a thickness of
The slab of 610mm.Heating of plate blank is to 1060 DEG C of temperature, soaking time 90min；Slab after heating is rolled, open rolling temperature
1015 DEG C of degree, 942 DEG C of finishing temperature, rolling mill screwdown regulation is 610mm-540mm-470mm-400mm-340mm-290mm-
245mm-215mm-190mm-170mm-150mm；Water cooling is carried out immediately to the steel plate after rolling, surface of steel plate after cooling returns red
327 DEG C of temperature, average 1.5 DEG C/s of cooling rate.Quenching+tempering heat treatment is carried out to steel plate.780 DEG C of hardening heat, when soaking
Between 15min, water cooling to 102 DEG C of temperature of surface of steel plate red temperature, average 1.2 DEG C/s of cooling rate；610 DEG C of tempering temperature,
Hot time 70min, steel plate is air-cooled to room temperature after tempering.
Obtained steel plate tissue contains martensite and austenite, and the volume fraction of austenite is 4%.The surrender of steel plate center portion
Intensity 745MPa, tensile strength 819MPa, elongation after fracture 15%, -60 DEG C of Charpy pendulum impact test impact absorbings of V-type sample
Energy 106J.The thickness direction contraction percentage of area 57% of steel plate.
Embodiment 4: 4 groups of parallel tests of design, constituent content and preparation method are substantially the same manner as Example 1, difference
It is start rolling temperature, shown in table 3 specific as follows.
The mechanical property of 1 embodiment of table, 4 steel plate
By table 1 it is found that 1-2 group is the start rolling temperature in the scope of the invention, and what 3-4 group was outside the scope of the present invention opens
Temperature is rolled, the elongation after fracture, low-temperature impact work and the contraction percentage of area performance in plate thickness direction for preparing steel plate are poor.
Embodiment 5: 3 groups of parallel tests of design, constituent content and preparation method are substantially the same manner as Example 2, difference
It is, the cooling velocity of water cooling after quenching, shown in table 2 specific as follows.
The mechanical property of 2 embodiment of table, 5 steel plate
By table 2 it is found that the 1st group of average cooling rate for water cooling after the quenching in the scope of the invention, and 2-3 group is
Average cooling rate outside invention scope.The steel plate yield strength and low-temperature impact work performance of group number 2 are poor；The steel plate of group number 3 is low
Warm ballistic work performance is poor, and occurs crackle caused by thermal stress on steel plate.
Claims (10)
1. a kind of 690MPa grades of super-thick steel plate, which is characterized in that the mass percentage content of chemical component are as follows: C:0.04-
0.08%, Mn:5.2-6.0%, Si:0.1-0.4%, Mo:0.1-0.5%, Ni:0.2-0.6%, Cr:0.2-0.6%, Ti:
0.01-0.05%, S :≤0.005%, P :≤0.010% and surplus Fe and impurity.
2. 690MPa grades of super-thick steel plate according to claim 1, which is characterized in that the steel plate with a thickness of 80-150mm.
3. 690MPa grades of super-thick steel plate according to claim 1, which is characterized in that the microstructure of the steel plate has geneva
Body and austenite；Wherein, the volume fraction of austenite is 4-10%.
4. 690MPa grades of super-thick steel plate according to claim 3, which is characterized in that the austenite is in film-form, Ovshinsky
Body is distributed between martensite lath.
5. 690MPa grades of super-thick steel plate according to claim 1, which is characterized in that the center portion mechanical property of the steel plate are as follows:
Yield strength is not less than 690MPa, and tensile strength is not less than 770MPa, and elongation after fracture is not less than 14%, -60 DEG C of summers of V-type sample
It is not less than 80J than pendulum impact test impact absorbing energy.
6. 690MPa grades of super-thick steel plate according to claim 1, which is characterized in that the steel plate is stretched based on plate thickness direction
The contraction percentage of area is not less than 50%.
7. a kind of preparation method of 690MPa according to claim 1-6 grades of super-thick steel plates, which is characterized in that packet
Include following steps:
(1) converter smelting is carried out after desulfurizing iron processing, reduces S, P content to S≤0.005% in molten steel, P≤0.010%；
(2) alloying of mass fraction needed for LF refining completes C, Mn, Si, Mo, Ni, Ti element carries out RH processing, vacuum later
Degree≤4mbar handles time >=20min；
(3) casting obtains slab, ratio >=4 of slab thickness and steel plate thickness；
(4) heating of plate blank, 1060-1140 DEG C of temperature；
(5) slab after heating is rolled, start rolling temperature≤1020 DEG C, finishing temperature >=930 DEG C, passage deformation quantity >=
10%；
(6) water cooling, surface of steel plate red temperature≤360 DEG C after cooling, average cooling speed are carried out immediately to the steel plate after rolling
1-5 DEG C of rate/s；
(7) steel plate is reheated to 780-830 DEG C by quenching heat treatment, and soaking time 5-15min, water cooling to surface of steel plate is returned
Red temperature≤110 DEG C temperature, average 2-8 DEG C of cooling rate/s；
(8) quenched steel plate is heated to 610-640 DEG C, soaking time 40-70min by tempering heat treatment, and steel plate is empty after tempering
It is cooled to room temperature.
8. preparation method according to claim 6, which is characterized in that in the step (3) slab using continuous casting steel billet or
Person's mould precast-forging slab.
9. preparation method according to claim 7, which is characterized in that as slab thickness≤320mm, using continuous casting plate
Base；As slab thickness > 320mm, using mould precast-forging slab.
10. preparation method according to claim 6, which is characterized in that in the step (4), the soaking time of slab is
40-90min。
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| PCT/CN2019/122904 WO2020143367A1 (en) | 2019-01-07 | 2019-12-04 | 690 mpa grade super-thick steel plate and manufacturing method therefor |
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| WO2020143367A1 (en) * | 2019-01-07 | 2020-07-16 | 南京钢铁股份有限公司 | 690 mpa grade super-thick steel plate and manufacturing method therefor |
| CN112359289A (en) * | 2020-11-23 | 2021-02-12 | 马鞍山钢铁股份有限公司 | Super-thick Q355-grade hot-rolled H-shaped steel with good low-temperature toughness and production method thereof |
| CN112899584A (en) * | 2021-01-15 | 2021-06-04 | 南京钢铁股份有限公司 | Ultralow temperature L-shaped steel and manufacturing method thereof |
| WO2021258584A1 (en) * | 2020-06-24 | 2021-12-30 | 南京钢铁股份有限公司 | 800 mpa construction machinery medium-manganese medium-thickness steel and manufacturing method therefor |
| CN115323251A (en) * | 2022-08-24 | 2022-11-11 | 东北大学 | Super-thick, high-strength, high-toughness and high-homogeneity super-thick steel plate for hydropower and manufacturing method thereof |
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| CN112705582A (en) * | 2021-01-28 | 2021-04-27 | 李艳峰 | Lead foil forming method |
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| JP3228986B2 (en) * | 1992-02-12 | 2001-11-12 | 新日本製鐵株式会社 | Manufacturing method of high strength steel sheet |
| JP4283757B2 (en) | 2004-11-05 | 2009-06-24 | 株式会社神戸製鋼所 | Thick steel plate and manufacturing method thereof |
| CN102226255B (en) * | 2011-06-08 | 2013-06-12 | 江苏省沙钢钢铁研究院有限公司 | Steel plate with high strength and toughness and 690MPa of yield strength and preparation process thereof |
| CN103031498B (en) * | 2012-12-17 | 2015-01-21 | 南京钢铁股份有限公司 | Manufacture method of extremely thick ocean engineering steel plate with low compression ratio and super high-strength strain age |
| JP5950045B2 (en) * | 2013-12-12 | 2016-07-13 | Ｊｆｅスチール株式会社 | Steel sheet and manufacturing method thereof |
| JP6237343B2 (en) | 2014-02-28 | 2017-11-29 | 新日鐵住金株式会社 | Melting method of high clean steel |
| CN104711489B (en) * | 2015-03-03 | 2017-03-29 | 山东钢铁股份有限公司 | A kind of effective high-ductility steel of spud leg semifocal chord and its manufacture method |
| CN106319380A (en) * | 2015-06-16 | 2017-01-11 | 鞍钢股份有限公司 | Low compression ratio 690MPa grade extra thick steel plate and production method thereof |
| CN109652733B (en) * | 2019-01-07 | 2021-01-26 | 南京钢铁股份有限公司 | 690 MPa-grade super-thick steel plate and manufacturing method thereof |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2020143367A1 (en) * | 2019-01-07 | 2020-07-16 | 南京钢铁股份有限公司 | 690 mpa grade super-thick steel plate and manufacturing method therefor |
| WO2021258584A1 (en) * | 2020-06-24 | 2021-12-30 | 南京钢铁股份有限公司 | 800 mpa construction machinery medium-manganese medium-thickness steel and manufacturing method therefor |
| CN112359289A (en) * | 2020-11-23 | 2021-02-12 | 马鞍山钢铁股份有限公司 | Super-thick Q355-grade hot-rolled H-shaped steel with good low-temperature toughness and production method thereof |
| CN112899584A (en) * | 2021-01-15 | 2021-06-04 | 南京钢铁股份有限公司 | Ultralow temperature L-shaped steel and manufacturing method thereof |
| CN115323251A (en) * | 2022-08-24 | 2022-11-11 | 东北大学 | Super-thick, high-strength, high-toughness and high-homogeneity super-thick steel plate for hydropower and manufacturing method thereof |
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| JP7267430B2 (en) | 2023-05-01 |
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