CN104046899B - 550MPa-grade steel sheet capable of being welded at high heat input and manufacturing method thereof - Google Patents
550MPa-grade steel sheet capable of being welded at high heat input and manufacturing method thereof Download PDFInfo
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Abstract
The invention relates to a 550MPa-grade steel sheet capable of being welded at a high heat input and a manufacturing method thereof. The steel sheet comprises the following components in percentage by weight: 0.04-0.08% of C, less than or equal to 0.10% of Si, 1.30-1.60% of Mn, less than or equal to 0. 013% of P, less than or equal to 0.003% of S, 0.05-0.30% of Cu, 0.25-0.55% of Ni, 0.0015-0.0030% of B, 0.008-0.016% of Ti, 0.015-0.030% of Nb, 0.0040-0.0080% of N, less than or equal to 0.010% of Al, 0.001-0.004% of Ca and the balance of Fe and unavoidable impurities. According to the steel sheet disclosed by the invention, ultralow carbon-ultralow Si-high Mn-Nb-based low-alloy steel is used as a basis, the content of Al in the steel is reduced, Ti-B microalloying is carried out, B/N is less than or equal to 0.25 and equal to or greater than 0.4, the ratio of Ca to S is 1.0-3.0, Ca*S is larger than 0.28 and is less than or equal to 1.0*10＜-3＞ and the TMCP (Thermal Mechanical Control Processing) process is optimized. The yield strength of the steel sheet is equal to or greater than 465MPa, the tensile strength of the steel sheet is 550-650MPa, the Charpy impact energy (single value) at -60 DEG C is equal to or greater than 100J, the steel sheet can be welded at a high heat input, and the Charpy impact energy (single value) of the welding heat affected zone of high-heat-input steel plate at -40 DEG C is equal to or greater than 100J.
Description
Technical field
The present invention relates to low-carbon (LC) (high intensity) low-alloy steel and its manufacture method, can high heat-input welding particularly to one kind
550mpa level steel plate and its manufacture method, this steel plate yield strength >=465mpa, tensile strength 550～650mpa, -60 DEG C summer
Charpy work((single value) >=100j, can high heat-input weldability steel plate, -40 DEG C of high heat-input steel plate welding heat affected zone
Charpy-V impact power (single value) >=100j.
Background technology
It is known that low-carbon (LC) (high intensity) low-alloy steel is one of most important structural timber, it is widely used in oil
Natural gas line, ocean platform, shipbuilding, bridge structure, boilers and pressure vessel, building structure, auto industry, railway transportation
And among machine-building.Low-carbon (LC) (high intensity) low-alloy steel performance depends on its chemical composition, the process system of manufacture process, its
Middle intensity, toughness and weldability are the most important performances of low-carbon (LC) (high intensity) low-alloy steel, and it is finally decided by finished steel
Microscopic structure state.Constantly advance with science and technology, people propose higher requirement to the obdurability of steel, weldability, that is,
Comprehensive mechanical performance and the serviceability of steel plate are significantly increased while maintaining relatively low manufacturing cost, to reduce steel
Consumption and cost-effective, mitigate steel beam column own wt, stability and security.
Start the research climax of development high-performance steel iron material of new generation at present in world wide, set by alloy combination
Meter, innovation controlled rolling/tmcp technology and Technology for Heating Processing obtain more preferable microscopic structure coupling so that steel plate obtain more excellent strong
Toughness, strong plasticity coupling, resistance to corrosion seawater, more excellent weldability and anti-fatigue performance.
Prior art manufacture yield strength >=420mpa, the steel plate of -60 DEG C of low-temperature impact toughness >=34j when, one
As to add a certain amount of ni or cu+ni element (>=0.30%) in steel, such as (thefirth (1986) international
Symposium and exhibit on offshore mechanics and arctic engineering, 1986,
Tokyo, japan, 354；“developments in materials for arctic offshore structures”；
“structural steel plates for arctic use produced by multipurpose accelerated
Cooling system " (Japanese), Kawasaki Steel skill report, 1985, no.1 68～72；“application of
accelerated cooling for producing360mpa yield strength steel plates of up to
150mm in thickness with low carbon equivalent ", accelerated cooling rolled
Steel, 1986,209～219；" high strength steel plates for ice-breaking vessels
Produced by thermo-mechanical control process ", accelerated cooling rolled
Steel, 1986,249～260；“420mpa yield strength steel plate with superior fracture
Toughness for arctic offshore structures ", kawasaki steel technical report,
1999, no.40,56；“420mpa and500mpa yield strength steel plate with high haz
Toughness produced by tmcp for offshore structure ", kawasaki steel technical
Report, 1993, no.29,54；“toughness improvement in bainite structure by thermo-
Mechanical control process " (Japanese) Sumitomo Metal Industries, vol.50, no.1 (1998), 26；" ice Haiti area uses
Offshore platform structure steel plate " (Japanese), steel research, the 1984, No. 314,19～43), to guarantee that mother metal steel plate has
Excellent low-temperature flexibility, using < when the heat input of 50kj/cm is welded, the toughness of heat affected area haz also can reach -60 DEG C of akv
≥34j；But using during super large heat input (>=100kj/cm) welding, the low-temperature flexibility of welding heat affected zone (haz) typically than
Compared with difficult to reach, there is serious deterioration in heat affected area (haz) low-temperature flexibility.
A large amount of patent documents only illustrate how to realize the low-temperature flexibility of mother metal steel plate, for how under soldering conditions,
Obtain the less of excellent heat affected area (haz) low-temperature flexibility explanation, how to ensure heat especially with during welding with ultra-great heat input
The low-temperature flexibility of the zone of influence (haz) is few, and in order to ensure the low-temperature flexibility of steel plate, generally individually adds a certain amount of in steel
Ni or cu+ni element, steel plate welding with ultra-great heat input heat affected area (haz) low-temperature flexibility is also less able to reach -60 DEG C, such as
(the clear 63-93845 of Japan Patent, clear 63-79921, clear 60-258410, spy is opened flat 4-285119, spy is opened flat 4-
308035th, flat 3-264614, flat 2-250917, flat 4-143246, United States Patent (USP) us patent4855106, us
patent5183198、us patent4137104).
The only nippon company improving welding with ultra-great heat input steel plate heat affected area (haz) low-temperature flexibility at present adopts
With Oxides Metallurgy Technology (us patent4629505, wo 01/59167a1), that is, in high heat-input welding process, molten
Near zygonema, due to long-time high temperature action, tin particle occurs to dissolve and ineffective, ti2o3More stable than tin, even if
Reach the fusing point of steel, also will not dissolve.ti2o3Particle can become acicular ferrite nucleating position in austenite crystal, promotes difficult to understand
Family name's body intragranular acicular ferrite (acicular ferrite-af) forming core, effective Ground Split austenite crystal, refine haz group
Knit, form the acicular ferrite structure of high-strength and high-ductility.
Content of the invention
It is an object of the invention to provide one kind can weld 550mpa level steel plate and its manufacture method, this steel plate by high heat-input
Yield strength >=465mpa, tensile strength 550～650mpa, -60 DEG C of Charpy-V impact power (single value) >=100j, can be hot greatly defeated
Enter the steel plate of weldability, Charpy-V impact power (the single value) >=100j of -40 DEG C of high heat-input steel plate welding heat affected zone.
For reaching above-mentioned purpose, the technical scheme is that
Can high heat-input welding low temperature structure steel plate be one of larger kind of difficulty in plate product, its reason is
Such steel plate does not require nothing more than ultralow c, low-carbon-equivalent ceq, high intensity, excellent low-temperature flexibility and anti-fatigue performance, and steel plate
Also to can bear high heat-input welding, welding heat affected zone low-temperature impact toughness is excellent；But these performance requirements are difficult to same
When meet.Ultralow c, low-carbon-equivalent ceq and high intensity collide with each other in composition design and technological design, are difficult to be in harmonious proportion, that is, drop
While low c content, carbon equivalent ceq, the high intensity of steel plate difficult to realize；While improving intensity, steel plate difficult to realize is excellent
Good weldability, especially high heat-input weldability.How to balance high intensity, low-temperature flexibility and high heat-input weldability is the present invention
One of maximum difficult point of product, is also key core technology.
Therefore, the present invention is in key technology route, composition and technological design, combines the impact high high intensity of steel plate, excellent
The key factor such as good low-temperature flexibility and high heat-input weldability, successfully avoids the blockade on new techniques of Nippon Steel Corp's patent
(titanium oxide metallurgical technology and magnesia metallurgical technology), starts with from alloy design, using the high mn-nb of the ultralow si- of Ultra-low carbon c-
Based on series low-alloy steel, reduce as far as possible the content of al in steel, ti-b microalloying, 0.25≤b/n≤0.45, [1.17
(%si)+6.77 (%al)+2.12 (%nb)+0.13 (%mn)] × (%c)≤0.053, ca process and ca/s ratio control
Between 1.0～3.0 and ca × s0.28≤1.0×10- 3, optimize tmcp technique, the microscopic structure making finished steel plate is a small amount of iron
The bainite of ferritic+Dispersed precipitate, microscopic structure average grain size below 10 μm, obtain even and excellent mother metal steel plate
While low-temperature flexibility, high heat-input welding when haz low-temperature flexibility similarly excellent, that is, -60 DEG C of akv of mother metal steel plate >=
100j, welding analog heat affected area (haz) -40 DEG C of akv >=100j, are particularly well-suited to the ship hull that opens ice, the ocean in ice Haiti area
Platform, bridge spanning the sea, oceanic winds tower structure, harbour machinery etc., and be capable of low cost stablize bulk industrial production.
Specifically, the present invention can high heat-input welding 550mpa level steel plate, its composition by weight percent is:
C:0.04%～0.08%
Si :≤0.10%
Mn:1.30%～1.60%
P :≤0.013%
S :≤0.003%
Cu:0.05%～0.30%
Ni:0.25%～0.55%
B:0.0015%～0.0030%
Ti:0.008%～0.016%
Nb:0.015%～0.030%
N:0.0040%～0.0080%
Al :≤0.010%
Ca:0.001%～0.004%
Remaining is fe and is inevitably mingled with；And above-mentioned element must simultaneously meet following relation:
0.25≤b/n≤0.45；
[1.17 (%si)+6.77 (%al)+2.12 (%nb)+0.13 (%mn)] × [(%c)+0.033 (%mn)]≤
0.053；
Ca process, and, ca/s ratio controls between 1.0～3.0 and ca × s0.28≤1.0×10- 3.
In steel plate component system of the present invention design:
In order to obtain uniformly excellent obdurability, strong plasticity coupling, and steel plate can bear Large Heat Input Welding, the present invention
Tmcp steel plate chemical composition has the feature that
C is very big on the especially high heat-input weldability impact of the intensity of tmcp steel plate, low-temperature flexibility, elongation percentage and weldability,
From improving tmcp steel plate low-temperature flexibility and high heat-input weldability angle it is desirable to c content controls relatively low steel；But from steel plate
The angle of microstructures Control and manufacturing cost during the intensity of steel, low-temperature flexibility and the manufacturing, c content should not control
Too low；It is too high that too low c content is easily caused crystal boundary migration rate, mother metal steel plate and welding haz microscopic structure coarse grains, and in steel
C content is too low to lead to grain-boundary weakness, serious deterioration mother metal steel plate and the low-temperature flexibility welding haz；Therefore, c content zone of reasonableness
For 0.04%～0.08%.
Mn as most important alloying element in steel except improve steel plate intensity in addition to, also have expansion austenite phase field,
Reduce ar3Point temperature, the effect refining tmcp steel plate bainite colony and improving steel plate low-temperature flexibility, promotion low temperature phase change tissue
Formed and improve the effect of armor plate strength；But mn is susceptible to segregation during molten steel solidification, when especially mn content is higher,
Not only result in pouring operation difficult, and easily occur to be conjugated segregation phenomena with the element such as c, p, s, especially in steel c content is relatively
Gao Shi, increase the segregation in strand centre and loose, serious strand central area be segregated in follow-up rolling, heat treatment and
Easily form abnormal structure in welding process, lead to steel plate low-temperature flexibility lowly and crackle in welding point；Therefore according to c content
Scope, selects suitable mn content range of crucial importance for tmcp steel plate, and suitable mn content is 1.30%～1.60%.
Si promotes deoxidation of molten steel and can improve armor plate strength, but the molten steel using al deoxidation, and the deoxidation of si is not
Greatly, although si can improve the intensity of steel plate, si seriously damages low-temperature flexibility, elongation percentage and the weldability of steel plate, especially
Under high heat-input welding condition, si not only promotes m-a island to be formed, and formed m-a island size is more thick, skewness
Even, seriously infringement welding heat affected zone (haz) low-temperature flexibility, the si content therefore in steel should as control low as possible it is considered to
To economy and the operability of steelmaking process, si content controls below 0.10%.
P is mingled with the mechanical performance to steel, especially low-temperature impact toughness, elongation percentage and weldability (especially as harmful in steel
High heat-input weldability) there is huge detrimental effect, it is more low better to require in theory；But in view of steel-making operability and refining
Steel cost, for require can Large Heat Input Welding, -60 DEG C of toughness, high intensity and can high heat-input welding tmcp steel plate, p contains
Amount needs control≤0.013%.
S as in steel harmful be mingled with the low-temperature flexibility to steel there is very big detrimental effect it is often more important that s in steel with
Mn combines, and forms mns field trash, and in the hot rolling, the plasticity of mns makes mns along rolling to extension, forms edge and rolls to mns folder
Debris band, the low-temperature impact toughness of serious infringement steel plate, elongation percentage, z to performance, weldability (especially high heat-input weldability),
Produce hot short essential element in s or course of hot rolling, it is more low better to require in theory simultaneously；But it is operable in view of steel-making
Property, steel-making cost and the smooth principle of logistics, for require can Large Heat Input Welding, -60 DEG C of toughness, high intensity and can high heat-input
The tmcp steel plate of welding, s content needs to control≤0.003%.
Cu is also austenite stabilizer element, adds cu and can also reduce ar3Point temperature, improves quenching degree, the steel of steel plate
The atmospheric corrosion resistance of plate and armor plate strength and low-temperature flexibility (acting on substantially under tmcp technique)；But cu addition is excessive (high
In 0.30%), steel plate high heat-input weldability drastically deteriorates；Cu addition is very few, less than 0.05%, is cut any ice very
Little；Therefore cu content controls between 0.05%～0.30%；Cu, ni are combined and add except the copper brittleness phenomenon reducing copper bearing steel, subtract
It is often more important that cu, ni are austenite stabilizer element outside the effect of corrosion cracking of light course of hot rolling, cu, ni are combined and add
Plus ar can be greatly lowered3, improve the driving force to ferrite transformation for the austenite, refinement microstructure, improve and improve steel plate
Intensity and low-temperature flexibility.
Add ni and not only can improve ferritic phase Dislocations mobility, promote dislocation commutative Banach aglebra, improve ferrite intrinsic
Toughness；Secondly, ni, as austenite stabilizer element, reduces ar3Point temperature, has the effect of refinement steel plate microscopic structure, because
This ni has raising tmcp armor plate strength, the function of low-temperature flexibility simultaneously.In steel plus ni can also reduce copper bearing steel copper brittleness existing
As mitigating the corrosion cracking of course of hot rolling, improving the atmospheric corrosion resistance of steel plate；Theoretically, in steel ni content certain
In the range of the higher the better, but too high ni content can hardened weld heat affected area, unfavorable to the high heat-input weldability of steel plate；
Ni is a kind of expensive heavy element simultaneously, considers, ni content controls between 0.25%～0.55%, to guarantee from the ratio of performance to price
The obdurability of the quenching degree of steel plate and steel plate, strong plasticity level and do not damage the weldability of steel plate.
In order to ensure there is certain solid solution b atom segregation in austenite grain boundary in steel, suppressing grain boundary ferrite to be formed, promoting
During tmcp, low temperature phase change tissue bainite/martensite is formed, and realizes Ultra-low carbon, the high intensity under the conditions of low-carbon-equivalent；Its
There is in secondary steel enough b atoms be combined with n atom, generate the bn particle of some Dispersed precipitate, promote high heat-input weldering
In termination process, ferrite crystal grain is formed in austenite crystal, splits former thick austenite crystal, refines high heat-input sweating heat
Zone of influence microscopic structure, improves Low Temperature Impact Toughness of Heat-affected Zone；B constituent content therefore in steel must not be less than 0.0015%；
But work as b too high levels in steel, fe thick in a large number is separated out on original austenite crystal prevention23(cn)6, serious embrittlement mother metal steel plate and
Low Temperature Impact Toughness of Heat-affected Zone and plasticity, are led to steel plate cold and hot working characteristic, are on active service to carry and are drastically disliked with cracking resistance crack arrest characteristic
Change, security during steel plate is on active service can not ensure, therefore steel plate b content must not exceed 0.0030%.
Ti is much larger than the affinity of b and n with n affinity, and during a small amount of interpolation ti, n is preferentially combined with ti, generates Dispersed precipitate
Tin particle, suppression heating of plate blank and course of hot rolling in austenite crystal too grow up, improve steel plate low-temperature flexibility；More important
Be that heat affected area (apart from melt run compared with far region) crystal grain is grown up, changed in suppression high heat-input welding process to a certain extent
Kind heat affected area toughness；Add ti content very few (0.008%) role less, when ti content adds excessive
(0.016%), in suppression steel, bn particle separates out, leads to bn number of particles rare it is impossible to improve high heat-input welding heat affected zone
Low-temperature flexibility；Additionally, when in steel, ti content is especially many, in steel, n major part is combined by ti, leads to solid solution b too high levels in steel,
Impact steel plate low-temperature flexibility and high heat-input weldability；Therefore suitable ti content range is 0.008%～0.016%.
Add micro nb element purpose in steel to be by non-recrystallization controlled rolling, improve tmcp armor plate strength and tough
Property, when nb addition be less than 0.015% when, except can not effectively performance controlled rolling effect in addition to, to tmcp steel plate strengthen ability
Not enough；When nb addition is more than 0.030%, induction upper bainite (bu) under high heat-input welding condition is formed and nb (c, n)
Secondary precipitation embrittling effect, the low-temperature flexibility of serious infringement high heat-input welding heat affected zone (haz), therefore nb content controls
Between 0.015%～0.030%, while obtaining optimal controlled rolling effect, realize tmcp steel plate obdurability/strong plasticity coupling,
Do not damage the toughness that high heat-input welds haz again.
Guarantee that having enough bn particles in high heat-input welding heat affected zone promotes ferrite forming core, splits heat affected area
Thick original austenite grain, refinement high heat-input welding heat affected zone microstructure improves high heat-input welding heat affected zone
Low-temperature flexibility, in steel, n content must not be less than 0.0040%；But when n too high levels in steel, the b atom in steel is all former with n
Son combines, and after generating bn particle, there is not solid solution b atom, lead under ultralow c, low-carbon-equivalent composition steel plate low intensity, no in steel
Exploitation can be met require；Additionally, excessive n content in steel reaches high heat-input welding heat affected zone solid solution n atom increasing, seriously
Deterioration Low Temperature Impact Toughness of Heat-affected Zone；Therefore in steel, n content must not exceed 0.0080%.
In order to ensure the bn particle that quantity of formation in steel is enough, aln particle is suppressed to generate in a large number, in steel, al upper content limit must
Must be controlled；Therefore, in steel, al must not be higher than 0.010%.
Ca process is carried out to steel, on the one hand can pure molten steel further, on the other hand denaturation is carried out to sulfide in steel
Process, be allowed to become non deformable, stablize tiny spherical sulfide, the red brittleness of suppression s, improve steel plate low temperature tough
Property, elongation percentage and z are to performance, the anisotropy of improving steel plate toughness.The number of ca addition, depending on the height of s content in steel
Low, ca addition is too low, and treatment effect is little；Ca addition is too high, and formation ca (o, s) is oversized, and fragility also increases, and can become
For fracture crack starting point, reduce low-temperature flexibility and the elongation percentage of steel, also reduce purity of steel, pollution molten steel simultaneously；Therefore
The OK range of ca content is 0.0010%～0.0040%.
Particularly, above-mentioned constituent content must simultaneously meet following relation:
0.25≤b/n≤0.45: ensure high heat-input welding heat affected zone have quantity enough, the bn of distribution disperse separates out
While, mother metal steel plate and welding heat affected zone are respectively provided with certain solid solution b atom to be existed.Realize following acting on: a) ultralow
Under the conditions of carbon, low-carbon-equivalent, by the high-hardenability of solid solution b it is ensured that the high intensity of mother metal steel plate, high intensity and low-temperature flexibility
Balance；Secondly solid solution b suppresses austenite grain boundary thick ferrite side plate in high heat-input welding heat affected zone to be formed, and promotes difficult to understand
Family name's body Intragranular Acicular Ferrite is formed, and improves the low-temperature flexibility of high heat-input welding heat affected zone；B) in steel plate experience high heat-input weldering
In termination process, the bn of welding heat affected zone Dispersed precipitate promotes austenite Intragranular Acicular Ferrite forming core, splits thick heat affected area
Original austenite grain, the microscopic structure of refinement heat affected area, improve the low-temperature flexibility of high heat-input welding heat affected zone.
[1.17 (%si)+6.77 (%al)+2.12 (%nb)+0.13 (%mn)] × [(%c)+0.033 (%mn)]≤
0.053: suppression high heat-input welding heat affected zone m-a forms, reduces heat affected area m-a quantity, reduces heat affected area m-a chi
Very little, promote heat affected area inner polygon ferrite transformation and m-a to decompose during Thermal Cycle, improve high heat-input welding
The low-temperature flexibility of heat affected area and cracking resistance, crack arrest characteristic, are greatly improved welding structure security reliability.
Ca processes and ca/s ratio controls between 1.0～3.0 and ca × s0.28≤1.0×10- 3: guarantee to vulcanize nodularization and folder
While debris are reduced to minimum to low-temperature flexibility and weldability impact, ca (o, s) uniform particle is tiny to be distributed in steel, suppression
High heat-input welding heat affected zone Austenite Grain Growth, improves Low Temperature Impact Toughness of Heat-affected Zone.
The present invention can high heat-input weld 550mpa level steel plate manufacture method, it comprises the steps:
1) smelt, cast
Smelt, be cast as slab according to mentioned component；Then heating of plate blank, temperature control 1030 DEG C～1130 DEG C it
Between it is ensured that in steel nb while being all solidly soluted in austenite during heating of plate blank, slab austenite crystal does not occur
Abnormality is grown up；
2) roll, steel plate overall compression ratio is slab thickness/finished steel plate thickness >=3.6
First stage is common rolling, carries out continuous rolling using milling train maximum rolling power, at utmost improves rolling line
It is ensured that deformation steel billet recrystallizes while production capacity, fining austenite grains；
Second stage adopts non-recrystallization controlled rolling, and controlled rolling start rolling temperature controls at 780 DEG C～820 DEG C, rolling pass
Reduction ratio >=7%, accumulative reduction ratio >=50%, 760 DEG C～800 DEG C of finishing temperature；
3) cool down
Controlled rolling carries out to steel plate accelerating cooling after terminating immediately, and steel plate opens 750 DEG C～790 DEG C of cold temperature, cooling velocity >=7
DEG C/s, stop cold temperature and be 350 DEG C～550 DEG C, subsequent steel plate natural air cooling carries out slow cooling to after 350 DEG C, retarded cooling process is steel plate
Temperature surface is at least incubated 24 hours under conditions of being more than 300 DEG C.
In manufacturing process of the present invention:
According to above-mentioned c, mn, nb, b and ti content range, slab heating temperature controls between 1030 DEG C～1130 DEG C, really
, while being all solidly soluted in austenite during heating of plate blank, there is not unusual length in slab austenite crystal to protect nb in steel
Greatly.
Steel plate overall compression ratio (slab thickness/finished steel plate thickness) >=3.6 it is ensured that rolling deformation is penetrated into steel plate core,
Improve steel plate centre microstructure variation.
First stage is common rolling, carries out continuous rolling using milling train maximum rolling power, at utmost improves rolling line
It is ensured that deformation steel billet recrystallizes while production capacity, fining austenite grains；
Second stage adopts non-recrystallization controlled rolling, according to nb element content range in above-mentioned steel, for guaranteeing not tie again
Brilliant controlled rolling effect, controlled rolling start rolling temperature controls at 780 DEG C～820 DEG C, rolling pass reduction ratio >=7%, accumulative reduction ratio >=
50%, 760 DEG C～800 DEG C of finishing temperature.
After controlled rolling terminates, steel plate is transported at acc equipment with the maximum delivery speed of roller-way immediately, immediately steel plate is carried out
Accelerate cooling；Steel plate opens 750 DEG C～790 DEG C of cold temperature finishing temperature, cooling velocity >=7 DEG C/s, stop cold temperature be 350 DEG C～
550 DEG C, subsequent steel plate natural air cooling carries out slow cooling to after 350 DEG C, and retarded cooling process is more than 300 DEG C of condition for steel billet temperature surface
Under be at least incubated 24 hours.
The invention has the beneficial effects as follows:
Steel plate of the present invention is by simple composition Combination Design, and combines with tmcp manufacturing process, not only gives birth at low cost
The tmcp steel plate of output high comprehensive performance, and significantly shorten the manufacturing cycle of steel plate, it is that enterprise's creation is huge
It is worth it is achieved that the environmental protection of manufacture process.The high-performance high added value of steel plate embodies a concentrated expression of steel plate and has high intensity, excellent
While different low-temperature flexibility, the weldability (especially high heat-input weldability) of steel plate is similarly excellent, successfully solves
Under the conditions of ultralow c, low-carbon-equivalent, steel plate obtains high intensity, excellent low-temperature flexibility, drastically increases large-scale heavy steel construction
Security and stability, anti-fatigue performance；Good weldability (especially high heat-input single pass welding) saves user's steel beam column system
The cost made, significantly shortens the time of user's steel beam column manufacture, is that user creates huge value.
Brief description
Fig. 1 is the photo of the microscopic structure (1/4 thickness) of steel embodiment 3 of the present invention.
Specific embodiment
With reference to embodiment and accompanying drawing, the present invention will be further described.
Table 1 is composition, its balance of fe and the inevitable impurity of steel embodiment of the present invention.Table 2～table 3 is respectively this
The manufacturing process of bright steel embodiment.Table 4 is the performance of embodiment of the present invention steel.
The microscopic structure that the microscopic structure of embodiment of the present invention steel as shown in Figure 1 can be seen that steel of the present invention is a small amount of
Ferrite+Dispersed precipitate bainite, microscopic structure average grain size is below 10 μm.
With Chinese national economy development, build the requirement of economizing type harmonious society, ocean development has swung to a day thing agenda,
At present China's ocean engineering is built and its associated equipment manufacturing industry is in the ascendant, ocean engineering construction and its associated equipment manufacturing industry
Critical material --- can have wide market prospects by high heat-input low temperature structure steel plate；Can high heat-input welding low temperature structure
Steel still belongs to a kind of brand-new steel grade for China.
Steel plate of the present invention is mainly used in the ship hull that opens ice in ice Haiti area, ocean platform, bridge spanning the sea, ocean wind tower knot
Structure, harbour machinery and antarctic investigation station steel construction etc., and be capable of low cost stablize bulk industrial production.
In sum, steel plate of the present invention is by simple composition Combination Design, and combines with tmcp manufacturing process, not only low
Become locally to produce the tmcp steel plate of high comprehensive performance, and significantly shorten the manufacturing cycle of steel plate, be enterprise's wound
Make huge value it is achieved that the environmental protection of manufacture process.The high-performance high added value of steel plate embodies a concentrated expression of Ultra-low carbon, low
Under the conditions of carbon equivalent, while steel plate has excellent obdurability, strong plasticity coupling, weldability (the especially large-line energy of steel plate
Weldability) similarly excellent, and successfully solve tmcp steel plate along the uneven problem of steel plate thickness directional performance, greatly
Improve security and stability, the anti-fatigue performance of large-scale heavy steel construction；Good weldability saves user's steel beam column manufacture
Cost, shorten user's steel beam column manufacture time, be that user creates huge value.
Claims (2)
1. one kind can weld 550mpa level steel plate by high heat-input, and its composition by weight percent is:
C:0.04%～0.08%
Si :≤0.10%
Mn:1.30%～1.60%
P :≤0.013%
S :≤0.003%
Cu:0.05%～0.30%
Ni:0.25%～0.55%
B:0.0015%～0.0030%
Ti:0.008%～0.016%
Nb:0.015%～0.030%
N:0.0040%～0.0080%
Al :≤0.010%
Ca:0.001%～0.004%
Remaining is fe and is inevitably mingled with；And above-mentioned element must simultaneously meet following relation:
0.25≤b/n≤0.45；
[1.17 (%si)+6.77 (%al)+2.12 (%nb)+0.13 (%mn)] × [(%c)+0.033 (%mn)]≤
0.053；
Ca process, and, ca/s ratio controls in 1.0～3.0, ca × s0.28≤1.0×10- 3；And obtained using following methods: include
Following steps:
1) smelt, cast
Composition according to claim 1 is smelted, is cast as slab；Then heating of plate blank, temperature control is at 1030 DEG C～1130 DEG C
Between it is ensured that in steel nb while being all solidly soluted in austenite during heating of plate blank, slab austenite crystal is not sent out
Raw abnormality is grown up；
2) roll, steel plate overall compression ratio is slab thickness/finished steel plate thickness >=3.6
First stage is common rolling, carries out continuous rolling using milling train maximum rolling power, at utmost improves rolling line production capacity
While it is ensured that deformation steel billet recrystallizes, fining austenite grains；
Second stage adopts non-recrystallization controlled rolling, and controlled rolling start rolling temperature controls at 780 DEG C～820 DEG C, and rolling pass is depressed
Rate >=7%, accumulative reduction ratio >=50%, 760 DEG C～800 DEG C of finishing temperature；
3) cool down
Controlled rolling carries out to steel plate accelerating cooling after terminating immediately, and 750 DEG C～790 DEG C of cold temperature opened by steel plate, and cooling velocity >=7 DEG C/
S, stops cold temperature and is 350 DEG C～550 DEG C, subsequent steel plate natural air cooling carries out slow cooling to after 350 DEG C, and retarded cooling process is steel billet temperature
Surface is at least incubated 24 hours under conditions of being more than 300 DEG C.
2. as claimed in claim 1 can high heat-input weld 550mpa level steel plate manufacture method, it is characterized in that, including as follows
Step:
1) smelt, cast
Composition according to claim 1 is smelted, is cast as slab；Then heating of plate blank, temperature control is at 1030 DEG C～1130 DEG C
Between it is ensured that in steel nb while being all solidly soluted in austenite during heating of plate blank, slab austenite crystal is not sent out
Raw abnormality is grown up；
2) roll, steel plate overall compression ratio is slab thickness/finished steel plate thickness >=3.6
First stage is common rolling, carries out continuous rolling using milling train maximum rolling power, at utmost improves rolling line production capacity
While it is ensured that deformation steel billet recrystallizes, fining austenite grains；
Second stage adopts non-recrystallization controlled rolling, and controlled rolling start rolling temperature controls at 780 DEG C～820 DEG C, and rolling pass is depressed
Rate >=7%, accumulative reduction ratio >=50%, 760 DEG C～800 DEG C of finishing temperature；
3) cool down
Controlled rolling carries out to steel plate accelerating cooling after terminating immediately, and 750 DEG C～790 DEG C of cold temperature opened by steel plate, and cooling velocity >=7 DEG C/
S, stops cold temperature and is 350 DEG C～550 DEG C, subsequent steel plate natural air cooling carries out slow cooling to after 350 DEG C, and retarded cooling process is steel billet temperature
Surface is at least incubated 24 hours under conditions of being more than 300 DEG C.
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| CN106755869B (en) * | 2016-12-27 | 2018-07-27 | 内蒙古科技大学 | A kind of method of low energy consumption production Q550D steel plates |
| CN108624819B (en) * | 2017-03-24 | 2020-08-25 | 宝山钢铁股份有限公司 | Low-cost large-heat-input welding 460 MPa-grade crack arrest steel plate and manufacturing method thereof |
| CN111621694B (en) * | 2019-02-28 | 2021-05-14 | 宝山钢铁股份有限公司 | Low-cost high-crack-resistance super-thick steel plate and manufacturing method thereof |
| CN112746218B (en) * | 2019-12-30 | 2021-11-16 | 宝钢湛江钢铁有限公司 | Low-cost, high-crack-resistance and high-heat-input-welding YP 420-grade steel plate and manufacturing method thereof |
| CN112746158A (en) * | 2019-12-30 | 2021-05-04 | 宝钢湛江钢铁有限公司 | YP460MPa thick steel plate with low cost, high crack resistance and high weldability and manufacturing method thereof |
| CN114107828A (en) * | 2020-08-27 | 2022-03-01 | 宝山钢铁股份有限公司 | Steel plate for high-heat-input welding with tensile strength of 570MPa and manufacturing method thereof |
| CN118547224A (en) * | 2024-07-29 | 2024-08-27 | 江苏沙钢钢铁有限公司 | 950 MPa-level steel plate for hydropower and preparation method thereof |
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Effective date of registration: 20180913 Address after: 524072 building 12-15, building 46, Renmin Road, Zhanjiang, Guangdong Co-patentee after: Baoshan Iron & Steel Co., Ltd. Patentee after: Baosteel Zhanjiang Iron & Steel Co., Ltd. Address before: 201900 Fujin Road, Baoshan District, Shanghai 885 Patentee before: Baoshan Iron & Steel Co., Ltd. |