CN107587037A - A kind of atmosphere corrosion resistance structural steel molten steel and the atmosphere corrosion resistance structural steel of nitrogen containing niobium and its production method - Google Patents
A kind of atmosphere corrosion resistance structural steel molten steel and the atmosphere corrosion resistance structural steel of nitrogen containing niobium and its production method Download PDFInfo
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Abstract
The present invention relates to field of steel-making, specifically provides a kind of atmosphere corrosion resistance structural steel molten steel, on the basis of the gross weight of molten steel, molten steel consists of the following composition：0.01% 0.09% C, 0.15% 0.35% Si, 0.30% 0.60% Mn, 0.30% 0.40% Cu, 0.20% 0.30% Ni, 3.5% 5.0% Cr, 0.16% 0.20% V, 0.01% 0.015% Nb, 0.021% 0.030% N, P no more than 0.030%, the S no more than 0.020%, remaining is inevitable impurity and Fe.The invention provides a kind of atmosphere corrosion resistance structural steel and its production method.The center mass of strand can be improved using the molten steel continuous casting of the present invention, centre burst and central pipe is avoided the occurrence of, thus can improve the quality of the high atmosphere corrosion resistance structural steel strand of high intensity, strand qualification rate can increase substantially；And the atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability finally given is good and possesses higher strength character.
Description
Technical field
The present invention relates to a kind of atmosphere corrosion resistance structural steel molten steel and using the present invention molten steel carry out continuous casting,
Rolling atmosphere corrosion resistance structural steel, and the production method of a kind of atmosphere corrosion resistance structural steel and by the party
The atmosphere corrosion resistance structural steel that method obtains.
Background technology
Weather resisting steel, it is a kind of highly important steel, its weather-resistance is ordinary steel
2-8 times, coating improves 1.5-10 times.Because weather resisting steel is rotten relative to the anti-air of ordinary steel
The validity of erosion, there is good economy again relative to stainless steel, so having been obtained in countries in the world fast
Speed development, the various outdoor steel constructions used, rail truck and bridge are the scopes of its application.
The weather resisting steel kind of China's early stage mainly has the 09CuPCrNi similar to Cor Ten A,
And Cor Ten A simplification version 09Cu, the yield strength of two kinds under hot-rolled condition are generally
300-450MPa。
After 2000, to improve the low temperature impact properties of the yield strength of steel and steel, in 09CuPCrNi
On the basis of by reducing phosphorus, and improve manganese content, have developed sheet material class steel Q450NQR1 (
That is 09MnCuCrNi), Q450NQR1 uses controlled rolling and controlled cooling in plate rolling, so that it may it is strong to obtain surrender
Weather resisting steel of the degree not less than 450MPa.And the productive prospecting that section bar is unable to controlled rolling and controlled cooling is directed to,
By reducing 09CuPCrNi phosphorus contents and improving manganese content, and add vanadium and carry out microalloying, develop
The steel YQ450NQR1 (namely 09MnCuCrNiV) of section bar class, does not pass through controlled rolling in type steel production line
More than 450MPa can also be reached by controlling cold yield strength.
After 2010, preferably to improve the atmospheric corrosion resistance ability of steel, sheet material types of steel passes through further
Chromium content in steel is improved, have developed the S450EW that chromium content is up to 2.5%-5.5%, atmospheric corrosion resistance
Performance is even more that the kind has possessed large-scale production ability at present on Q450NQR1.But as type
The steel of material class, the square continuous casting billet produced after chromium content is improved, it is (main to there are obvious central defect
Crackle and central pipe centered on wanting), and the intensity index of final shaped steel does not reach the effect of sheet material class steel yet
Fruit, therefore, possess the section bar class steel for having more preferable atmospheric corrosion resistance ability and be also constantly in research and development.
The content of the invention
The technical problems to be solved by the invention, which are to provide one kind, can improve the high atmospheric corrosion resistance of high intensity
The center mass of shaped steel strand and the atmosphere corrosion resistance structural steel molten steel and one that hardness of steel index can be improved
Kind atmosphere corrosion resistance structural steel and its production method.
To realize object defined above, according to the first aspect of the invention, the invention provides a kind of resistance to air is rotten
Shaped steel molten steel is lost, on the basis of the gross weight of molten steel, molten steel consists of the following composition：0.01%-0.09
% C, 0.15%-0.35% Si, 0.30%-0.60% Mn, 0.30%-0.40% Cu,
0.20%-0.30% Ni, 3.5%-5.0% Cr, 0.16%-0.20% V, 0.01%-0.015
% Nb, 0.021%-0.030% N, the P no more than 0.030%, no more than 0.020%
S, remaining is inevitable impurity and Fe.
According to the second aspect of the invention, it is described resistance to big the invention provides a kind of atmosphere corrosion resistance structural steel
Gas corrosion shaped steel carries out continuous casting, rolling by molten steel of the present invention.
According to the third aspect of the invention we, the invention provides a kind of production method of atmosphere corrosion resistance structural steel,
This method includes：
(1) converter smelting and deoxidation alloying：Converter smelting and deoxygenation are carried out after molten iron is pre-processed
Aurification, wherein, controlling the outbound molten steel component of converter smelting and deoxidation alloying includes：C、Si、Mn、
Cr, Cu, Ni, P and S, and on the basis of the gross weight of molten steel, Cu contents be 0.30%-0.40%,
Ni contents are 0.20%-0.30%, P≤0.03% and S≤0.02%；
(2) LF stoves refine：Molten steel obtained by step (1) is refined in LF stoves；
Wherein, jointly controlled by step (1) and step (2) so that the outbound molten steel of LF stoves respectively into
Weight content is divided to meet：C content is 0.01%-0.09%, and Si contents are 0.15%-0.35%, Mn contents
For 0.30%-0.60%, Cr contents are 3.5%-5.0%, and Cu contents are 0.30%-0.40%, and Ni contents are
0.20%-0.30%, V content 0.16%-0.20%, Nb content are 0.01%-0.015%, and N contains
Measure as 0.021%-0.030%, P≤0.03% and S≤0.02%；
(3) continuous casting：Molten steel obtained by step (2) is subjected to continuous casting and obtains strand；
(4) roll：Rail will be rolled into after heating strand obtained by step (3).
According to the fourth aspect of the invention, produce to obtain the invention provides the method according to the present invention resistance to
Atmospheric corrosion shaped steel, on the basis of the gross weight of atmosphere corrosion resistance structural steel, consist of the following composition：
0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60% Mn, 0.30%-0.40
% Cu, 0.20%-0.30% Ni, 3.5%-5.0% Cr, 0.16%-0.20% V, 0.01
%-0.015% Nb, 0.021%-0.030% N, the P no more than 0.030%, are not more than
0.020% S, remaining is inevitable impurity and Fe；Wherein, atmosphere corrosion resistance structural steel
Rel >=475MPa, Rm >=650MPa.
The center mass of strand can be improved using the molten steel continuous casting of the present invention, avoid the occurrence of centre burst
And central pipe, the quality of the high atmosphere corrosion resistance structural steel strand of high intensity thus can be improved, strand closes
Lattice rate can increase substantially；And the atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability finally given is good
And possesses higher strength character.
The present inventor speculate, be due to the present invention in the high weather resisting steel of high intensity add vanadium,
Niobium and nitrogen, can form a large amount of V (C, N) and Nb (C, N) particle, and these particles can refine strand
Crystal grain, the development of strand dendrite is prevented, so as to avoid strand center cracked and hole.In addition,
These V (C, N) and Nb (C, N) particles can dissolve in austenite mostly in subsequent heating strand,
Particle separates out again in rolling of sectional iron and cooling procedure after rolling, produces precipitation strength effect, improves steel
Intensity.So that the present invention can not only improve strand center mass, and atmospheric corrosion resistance can be improved
The strength character and decay resistance of shaped steel.
Other features and advantages of the present invention will be described in detail in subsequent specific embodiment part.
Brief description of the drawings
Accompanying drawing be for providing a further understanding of the present invention, and a part for constitution instruction, with
Following embodiment is used to explain the present invention together, but is not construed as limiting the invention.
In accompanying drawing：
Fig. 1 is the sectional drawing (non-acid etching) of the continuous casting billet of compared steel 1；
Fig. 2 is to use the sectional drawing after rolling of sectional iron a time after the continuous casting billet of compared steel 1 heats；
Fig. 3 is the sectional drawing of the continuous casting billet of compared steel 2 (after acid etching)；
Fig. 4 is the Cross Section of CC Billet figure of steel 2 of the present invention (after acid etching)；
Fig. 5 is the cross-sectional view of heavy section steel.
Embodiment
The embodiment of the present invention is described in detail below.It should be appreciated that this place is retouched
The embodiment stated is merely to illustrate and explain the present invention, and is not intended to limit the invention.
The end points of disclosed scope and any value are not limited to the accurate scope or value herein, this
A little scopes or value should be understood to comprising the value close to these scopes or value.For number range, respectively
Between the endpoint value of individual scope, between the endpoint value of each scope and single point value, and single point
Can be combined with each other between value and obtain one or more new number ranges, these number ranges should by regarding
For specific disclosure herein.
As it was previously stated, the invention provides a kind of atmosphere corrosion resistance structural steel molten steel, using the gross weight of molten steel as
Benchmark, molten steel consist of the following composition：0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60
% Mn, 0.30%-0.40% Cu, 0.20%-0.30% Ni, 3.5%-5.0% Cr, 0.16%-0.20
% V, 0.01%-0.015% Nb, 0.021%-0.030% N, the P no more than 0.030%,
S no more than 0.020%, remaining is inevitable impurity and Fe.Connected using the molten steel of aforementioned component
Casting obtained strand (alternatively referred to as continuous casting billet) center mass is improved, Cross Section of CC Billet center (acid
After erosion) basic non-stop layer crackle and hole.
, according to the invention it is preferred on the basis of the gross weight of molten steel, molten steel consists of the following composition：
0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60% Mn, 0.30%-0.40%
Cu, 0.20%-0.30% Ni, the Cr higher than 3.5% to 5.0%, 0.16%-0.20% V, 0.01
%-0.015% Nb, 0.021%-0.030% N, the P no more than 0.030%, no more than 0.020
% S, remaining is inevitable impurity and Fe.
, according to the invention it is preferred on the basis of the gross weight of molten steel, molten steel consists of the following composition：
0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60% Mn, 0.30%-0.40%
Cu, 0.20%-0.30% Ni, 3.6% to 5.0% Cr, 0.16%-0.20% V, 0.01%
- 0.015% Nb, 0.021%-0.030% N, the P no more than 0.030%, no more than 0.020%
S, remaining is inevitable impurity and Fe.
The present inventor makes above-mentioned technical proposal and realizes the purpose of the present invention, is based on long-term
Theory analysis and put into practice discovery and obtain.
Specifically, the present inventor has found by theory analysis and practice：
C, Si, Mn are the elements of most economical raising hardness of steel, with C, Si, Mn component in steel
Increase, the intensity of steel significantly rises, but the toughness of steel and weldability decline therewith, and shaped steel generally will
Ask with good weldability and toughness, so application claims C is controlled in the range of 0.01%-0.09%,
Si is controlled in the range of 0.15%-0.35%, and Mn is controlled in the range of 0.30%-0.60%.
P is one of the element for improving steel atmospheric corrosion resistance ability, the P content of Cu-P systems weather resisting steel
Up to 0.07%-0.12%.But P is the element for improving black brittleness transition temperature again, is unfavorable for the low of steel
Warm impact property, make the low temperature impact properties simultaneously containing atmosphere corrosion resistance structural steels such as Cr, Ni, Cu big
Width declines, and therefore, limits P≤0.030%.
In addition to automatic steel, S is harmful element, more low better, therefore is limited to less than 0.020%.
Cu, Cr and Ni in steel, can both make steel have good atmospheric corrosion resistance ability, and and can improves
The intensity of steel.But because Cu and Ni alloys price is far above Cr alloys, from the economy of steel,
Cu is in 0.30%-0.40% for present invention control, Cr 3.5%-5.0% (preferably above 3.5% to 5.0%,
More preferably 3.6%-5.0%), Ni is in the range of 0.20%-0.30%.But because Cr contents are very high, cause
The poor fluidity of molten steel, with reference to other alloys producings, easily there is underbead crack in strand, the point
Other technical measures must be taken to give to overcome.
For overcome Cr contents improve bring the defects of, the present invention added in molten steel V, N,
Nb elements and the technical problem for solving the present invention, speculate these for the present inventor below
Element can improve strand center mass, and improve the possible cause of the intensity of steel：
V can also form V (C, N) particle, and strand dendrite can be also prevented in the cooling procedure of strand
Development, the possibility for forming thick dendrite is reduced, while the degree that strand selects part to crystallize also reduces, from
And strand internal structure is improved, avoid the formation of centre burst and hole.In addition, 2 Mo Steel Slab during Heating Process
In, V (C, N) particles start to be dissolved in austenite at 600 DEG C or so, and 900 DEG C -1000 DEG C are completely dissolved in
Austenite, separated out in subsequent rolling and roller repairing from austenite, precipitation strength positive effect.
To ensure to obtain a certain amount of V (C, N) particle, the V for adding 0.16%-0.20% is necessary.
Nb is also that can form Nb (C, N) particle, and strand tree can be also prevented in the cooling procedure of strand
The development of dendrite, the possibility for forming thick dendrite is reduced, while the degree that strand selects part to crystallize also subtracts
It is small, so as to improve strand internal structure, avoid the formation of centre burst and hole.In addition, strand adds
In thermal process, Nb (C, N) particle can be also completely dissolved in austenite, and just can be from austenite in rolling
Middle precipitation, realizes Controlled Cooling, the significant ferrite crystal grain for refining steel, so as to improve the tough of steel
Property.
N content deficiency, forms that VC quantity is on the high side, and VN quantity is on the low side, is that unfavorable V is played and had
Benefit effect, therefore the present invention need to control N in the range of 0.021%-0.030%.N can be with furnace charge and conjunction
Gold ribbon enters in steel, liquid metal can also from air suction part N, usual BOF smelting steel
Residual N content be about 0.002%-0.008%, the residual N content of electric furnace smelting steel is about 0.006%
- 0.015%, so in BOF smelting steel, the alloy supplement part N containing N need to be used.
According to the molten steel of the present invention, preferably on the basis of the gross weight of molten steel, the Als contents in molten steel are
0.01%-0.03%.
According to the molten steel of the present invention, the preferably temperature of molten steel is 1535-1565 DEG C, before the present invention
State the molten steel of composition and control molten steel temperature be 1535-1565 DEG C, can directly carry out continuous casting, continuous casting
The center mass of obtained strand can further be improved, and finally can further improve hardness of steel
Index and decay resistance.
As it was previously stated, the invention provides a kind of atmosphere corrosion resistance structural steel, the atmosphere corrosion resistance structural steel by
Molten steel of the present invention carries out continuous casting, rolling.
According to the atmosphere corrosion resistance structural steel of the present invention, the temperature of preferably described continuous casting (or is Steel Melt for Continuous Casting
Temperature) be 1535-1565 DEG C, when the molten steel temperature within the range when, without further carry out
Temperature adjusts, and can directly carry out continuous casting.
According to the atmosphere corrosion resistance structural steel of the present invention, preferably the square billet obtained after continuous casting is cooled to
Slow cooling to room temperature is carried out after 500-700 DEG C to obtain strand and then being rolled, wherein, preferred slow cooling speed
For 5-100 DEG C/h, more preferably 10-30 DEG C/h.
Mode of the invention to slow cooling is without particular/special requirement, as long as meeting that this hair can be achieved in foregoing slow cooling speed
Bright purpose.Such as square billet heap can be entered to burial pit and carry out slow cooling.
Then burial pit can be for example capped by setting up melt pit and realize described delay to reduce cooldown rate
It is cold.
It was found by the inventors of the present invention that in slow cooling temperature control, excessive temperature adds burial pit,
Such as at more than 800 DEG C, strand or austenite structure, without ferromagnetism, it is unfavorable for ferromagnetic class
The safety operation of crane, therefore regulation is put into burial pit temperature not above 700 DEG C.Usual steel
Martensite transformation temperature is at 400 DEG C or so, in martensite transformation temperature scope, the strand of high-chromium
Even if the cooling velocity of steel is not reaching to the temperature Rate that martensitic traoformation occurs, faster cooling speed
Degree also results in casting billet surface and the internal a large amount of crackles of generation, therefore, it is specified that is put into the temperature of burial pit
Degree cannot be below 500 DEG C.
According to the atmosphere corrosion resistance structural steel of the present invention, the finishing temperature preferably rolled is 700-950 DEG C.
Continuous casting is carried out using the molten steel with aforementioned component, rolling is that can obtain meeting the resistance to of application claims
Atmospheric corrosion shaped steel, the present invention to the production method of the atmosphere corrosion resistance structural steel without particular/special requirement, according to
The present invention, in order to further improve strand center mass, improve strand central defect, and improve the strong of steel
Performance and decay resistance are spent, the production method of preferably atmosphere corrosion resistance structural steel of the invention includes：
(1) converter smelting and deoxidation alloying：Converter smelting and deoxygenation are carried out after molten iron is pre-processed
Aurification, wherein, controlling the outbound molten steel component of converter smelting and deoxidation alloying includes：C、Si、Mn、
Cr, Cu, Ni, P and S, and on the basis of the gross weight of molten steel, Cu contents be 0.30%-0.40%,
Ni contents are 0.20%-0.30%, P≤0.03% and S≤0.02%；
(2) LF stoves refine：Molten steel obtained by step (1) is refined in LF stoves；
Wherein, jointly controlled by step (1) and step (2) so that the outbound molten steel of LF stoves respectively into
Weight content is divided to meet：C content is 0.01%-0.09%, and Si contents are 0.15%-0.35%, Mn contents
For 0.30%-0.60%, Cr contents are that 3.5%-5.0% (is preferably above 3.5% to 5.0%, more preferably
3.6%-5.0%), Cu contents are 0.30%-0.40%, and Ni contents are 0.20%-0.30%, and V content is
0.16%-0.20%, Nb content are 0.01%-0.015%, N content 0.021%-0.030%,
P≤0.03%, S≤0.02%；
(3) continuous casting：Molten steel obtained by step (2) is subjected to continuous casting and obtains strand；
(4) roll：Rail will be rolled into after heating strand obtained by step (3).
The present inventor is by long-term theory analysis and puts into practice discovery, because Cu and Ni and O
Affinity is small, is not easy to be oxidized very much, and when converter smelting process adds, recovery rate just can reach 100%,
Therefore in the control of the step of converter procedure one in place, that is, control Cu and Ni respectively in 0.30%-0.40% and
In the range of 0.20%-0.30%, subsequently no longer it is adjusted.
With the method for the invention it is preferred in step (1), converter smelting and deoxidation alloying are controlled
Outbound molten steel temperature is 1550-1580 DEG C.
With the method for the invention it is preferred in step (1), converter smelting and deoxidation alloying are controlled
In outbound molten steel, on the basis of the gross weight of molten steel, Als contents are 0.02%-0.05%.
In the present invention, preferably converter uses Al deoxidization techniques, and controls Als (dissolved aluminum) to exist
In the range of 0.02%-0.05%, it is 1550-1580 DEG C to control converter tapping liquid temperature degree.Control herein
Als allows for rear portion LF stoves refining procedure and continuous casting steel machine is deposited in 0.02-0.05% scopes
Al is oxidized to there is Als2O3Phenomenon, the Als of two-step scaling loss amount typically exists
In the range of 0.010%-0.02%, by a large amount of it was verified that the finally casting after continuous casting steel machine after cooling
The Als of base can be in the range of 0.01-0.03%.
With the method for the invention it is preferred in step (2), the outbound molten steel temperature of LF stoves is controlled to be
1570-1600℃。
With the method for the invention it is preferred in step (2), control in the outbound molten steel of LF stoves, with molten steel
Gross weight on the basis of, Als contents are 0.01%-0.03%.
With the method for the invention it is preferred in step (3), Continuous Cast Molten Steel Temperature is 1535-1565 DEG C.
With the method for the invention it is preferred in step (3), the square billet obtained after continuous casting is cooled to
Slow cooling to room temperature is carried out after 500-700 DEG C and obtains the strand.
With the method for the invention it is preferred to slow cooling speed is 5-100 DEG C/h, more preferably 10-30 DEG C/h.
With the method for the invention it is preferred in step (4), temperature after heating is 1100-1250 DEG C.
With the method for the invention it is preferred in step (4), finishing temperature is 700-950 DEG C.
In the present invention, converter smelting and deoxidation alloying, the refining of LF stoves, continuous casting and rolling can be according to
Conventional steps are carried out, as long as its technological parameter disclosure satisfy that the preferred requirement of the present invention can be realized preferably
The purpose of the present invention.
In the present invention, after rolling, the method for natural air cooling can be used to be cooled down.
The method according to the invention, the LF stoves refining can be carried out according to conventional steps, for this hair
Bright, in preferred steps (2), the refining of LF stoves includes：
I) optionally, the slag on molten steel surface obtained by step (1) is reduced with aluminum shot, aluminum shot
Dosage is 0-1.5kg/ ton steel；
Ii) with carbon line, ferrosilicon, ferromanganese and ferrochrome to C, Si, Mn in molten steel obtained by step (1)
It is adjusted with the content of Cr compositions so that meeting outbound molten steel requirement；
Iii) optionally, adjustment Als contents to meet outbound molten steel requirement；
Iiii) it is outbound make it that Nb contents, N content and V content meet for progress vanadium, nitrogen and niobium alloy
Molten steel requirement.
As it was previously stated, produce obtained atmospheric corrosion resistance type the invention provides the method according to the present invention
Steel.
According to the atmosphere corrosion resistance structural steel of the present invention, preferably using the gross weight of atmosphere corrosion resistance structural steel as base
Standard, consist of the following composition：0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60
% Mn, 0.30%-0.40% Cu, 0.20%-0.30% Ni, 3.5%-5.0% Cr are (excellent
Choosing is higher than 3.5% to 5.0%, more preferably 3.6%-5.0%), 0.16%-0.20% V, 0.01%-0.015
% Nb, 0.021%-0.030% N, the P no more than 0.030%, no more than 0.020%
S, remaining is inevitable impurity and Fe.
According to the present invention atmosphere corrosion resistance structural steel, preferably atmosphere corrosion resistance structural steel Rel >=475MPa,
Preferably 475-525MPa.
According to the present invention atmosphere corrosion resistance structural steel, preferably atmosphere corrosion resistance structural steel Rm >=650MPa,
Preferably 650-685MPa.
The atmospheric corrosion resistance type of preferred embodiment production present invention according to the present invention a kind of is described below
The specific implementation step of steel is resistance to big according to step production in embodiment (i.e. steel 1-4 of the present invention in table)
Gas corrosion shaped steel：
Key step includes：Converter smelting and deoxidation alloying → LF stoves refining → continuous casting → strand
Heating → shape rolling mill rolling.
Concrete operations content per process is as follows：
A converter smeltings and deoxidation alloying
During using converter smelting molten steel, C, Si, Mn and Cr chemical constituent control mesh in molten steel
It is designated as：C 0.01%-0.09%, Si 0.15%-0.35%, Mn 0.30%-0.60% and Cr 3.5%-5.0
% (preferably above 3.5% to 5.0%, more preferably 3.6%-5.0%).This process is only control targe,
The process can not be such as controlled in target zone, and follow-up LF stoves refining procedure is also adjustable.
Control P≤0.030%, S≤0.020% in molten steel.
Because Cu and Ni and O affinity is small, it is not easy to be oxidized very much, in converter smelting work
Recovery rate just can reach 100% when skill adds, therefore in the control of the step of converter procedure one in place, that is, control
Cu and Ni processed in the range of 0.30%-0.40% and 0.20%-0.30%, are subsequently no longer carried out respectively
Adjustment.
Converter uses Al deoxidization techniques, and controls Als (dissolved aluminum) in 0.02%-0.05% scopes
Interior, it is 1550-1580 DEG C to control converter tapping liquid temperature degree.Als is controlled herein in 0.02-0.05%
Scope, allows for rear portion LF stoves refining procedure and continuous casting steel machine there are Als and be oxidized to
Al2O3Phenomenon, the Als of two-step scaling loss amount typically in the range of 0.010%-0.02%,
By a large amount of it was verified that the Als of strand after being cooled down after last continuous casting steel machine can be
In the range of 0.01-0.03%.
B LF stoves refine
Molten steel optionally includes adding the step of aluminum shot reduces slag when LF stoves refine,
Aluminum shot addition is 0-1.5kg/ ton steel；
After LF stove electrical heating, with carbon line, ferrosilicon, ferromanganese and ferrochrome to C, Si, Mn and Cr
Composition carries out micro adjustment, and adjusting range is respectively in 0.01%-0.09% (C), 0.15%-0.35%
(Si), 0.30%-0.60% (Mn) and 3.5%-5.0% (are preferably above 3.5% to 5.0%, more
It is preferred that 3.6%-5.0%) in (Cr).
After being finely tuned to C, Si, Mn and Cr, Als in sampling analysis molten steel, Als contents are adjusted
For 0.01%-0.03%；As Als be less than 0.02%, then need using add aluminum shot or feeding aluminum steel
Method Als is adjusted to 0.025% or so, it is ensured that after continuous casting cast steel strand Als control
In the range of 0.01%-0.03%.Als is controlled to allow for rear portion company 0.025% or so herein
Continuous cast steel process there are Als and be oxidized to Al2O3Phenomenon, by a large amount of it was verified that even
Continuous cast steel process strand Als oxidation is in the range of 0.005-0.015%.
After adjusting Als, ferro-niobium and VN alloy (VN12, VN14 and VN16) are added,
The V in molten steel is set to control in the range of 0.16%-0.20%, Nb is controlled in 0.010%-0.015% models
In enclosing, N is controlled in the range of 0.021%-0.030%, controls the outbound molten steel temperature of LF stoves to be
1570-1600℃。
C continuous castings
Chemical composition (percentage by weight) be 0.01%-0.09% C, 0.15%-0.35% Si,
0.30%-0.60% Mn, 0.30%-0.40% Cu, 0.20%-0.30% Ni, 3.5%-5.0
% (preferably above 3.5% to 5.0%, more preferably 3.6%-5.0%) Cr, 0.16%-0.20% V,
0.01%-0.015% Nb, 0.021%-0.030% N, the P no more than 0.030% and not
The molten steel of S more than 0.020% carries out continuous casting, and control continuous casting steel machine liquid temperature degree is at 1535-1565 DEG C
In the range of.
Strand is put into slow in cast molding on continuous casting casting machine and when being cooled in the range of 500-700 DEG C
Slow cooling is carried out in cold hole, burial pit is gone out after slow cooling to room temperature, slow cooling speed is 5-100 DEG C/h, preferably
For 10-30 DEG C/h.Casting ingot cross section quality is checked after going out hole, does not find centre burst and hole.
It was found by the inventors of the present invention that in slow cooling temperature control, excessive temperature adds burial pit,
Such as at more than 800 DEG C, strand or austenite structure, without ferromagnetism, it is unfavorable for ferromagnetic class
The safety operation of crane, therefore regulation is put into burial pit temperature not above 700 DEG C.Usual steel
Martensite transformation temperature is at 400 DEG C or so, in martensite transformation temperature scope, the strand of high-chromium
Even if the cooling velocity of steel is not reaching to the temperature Rate that martensitic traoformation occurs, faster cooling speed
Degree also results in casting billet surface and the internal a large amount of crackles of generation, therefore, it is specified that is put into the temperature of burial pit
Degree cannot be below 500 DEG C.
D heating strands and rolling
The high atmosphere corrosion resistance structural steel heating strand of high intensity is to after 1100 DEG C -1250 DEG C, then is cast
To the rolling of shaped steel, finishing temperature control is finally rolled into base in the range of 700 DEG C -950 DEG C
Shaped steel is by the way of natural air cooling, you can obtains Rel >=475MPa, Rm >=650MPa, relatively
Rate of corrosion (relative to YQ450NQR1 high-strength weather resisting steels) is 60%-65% height
The high atmosphere corrosion resistance structural steel of intensity.
Table 1 is the atmospheric corrosion resistance of the steel of the present invention and compared steel produced under same process conditions,
Intensity index, and the contrast situation of strand central defect.
Steel of the present invention 1,2,3 and 4 in table 1 is to use foregoing " converter smelting and deoxygenation
Aurification → LF stoves refining → continuous casting → heating strand → shape rolling mill rolling " technique productions steel of the present invention
Chemical constituent, wherein, converter smelting and deoxidation alloying → LF stoves refining → continuous casting → strand
The main control parameters of heating → shape rolling mill rolling are shown in Table 2；
Compared steel 1 in table 1 is using foregoing " converter smelting and deoxidation alloying → LF stoves essence
Refining → continuous casting → heating strand → shape rolling mill rolling " technique, C, Si of production, Mn, Cr,
Ni and Cu chemical compositions and this identical of base steel compared steel of the present invention；
Compared steel 2 in table 1 is using foregoing " converter smelting and deoxidation alloying → LF stoves essence
Refining → continuous casting → heating strand → shape rolling mill rolling " technique, the existing YQ450NQR1 of production
The chemical composition of high strength atmospheric corrorsion resistant section steel；
The assay method of Rel and Rm in table 1 are GB/T228-2002 (metal material room temperatures
Stretching test method)；
The test method of relatively corrosive rate by the former Ministry of Railways " TB/T2375-93 ", (use by railway in table 1
Weathering steel alternate-immersion test method) as defined in method measure, its specific location parameter is：
Test sample is processed into 60mm × 40mm × 4mm rectangle, it is desirable to which the surface roughness of largest face is
3.2μm；Temperature is 45 ± 2 DEG C；Humidity is：70 ± 5%RH；Each cycle period is 60 ± 3min (its
Middle infiltrating time is 12 ± 1.5min)；Cycle period is 75h；Specimen surface maximum temperature is after baking
70±10℃；Solution is：(1.0±0.05)×10-2mol/l NaHSO3Solution.The basis of relatively corrosive rate
Steel grade is chosen to be YQ450NQR1 (compared steel 2) high strength atmospheric corrorsion resistant section steel, i.e.,
The relatively corrosive rate of YQ450NQR1 high strength atmospheric corrorsion resistant section steels is 100%.
The sampling point and sampling state of intensity index and relatively corrosive rate measure sample are in table 1：
The heavy section steel produced using technique described in the present invention and parameter, sectional shape are shown in Fig. 5,
And at the 1/2 of Fig. 5 c positions (short-leg), and prolong rolling direction and take tension test and corrosion
Test piece sample.
Wherein, Fig. 1 is the sectional drawing (non-acid etching) of the continuous casting billet (also referred to as strand) of compared steel 1, by
There is 30mm crackle+hole pattern in the centre that Fig. 1 can be seen that compared steel 1.
Wherein, Fig. 2 uses the sectional drawing after rolling of sectional iron a time after being heated for the continuous casting billet of compared steel 1,
By Fig. 2 it can be found that crackle extends, whole strand is caused to be scrapped；
Wherein, Fig. 3 is the sectional drawing (after acid etching) of the continuous casting billet of compared steel 2, because Cr contents are low,
And other alloying element total amounts are also below the alloy total amount of chemical composition in compared steel 1, therefore after acid etching
Cross Section of CC Billet center do not find crackle and hole.
Wherein, Fig. 4 is the Cross Section of CC Billet figure (after acid etching) of steel 2 of the present invention, observes Fig. 4 pattern,
It was found that Cross Section of CC Billet center does not find centre burst and hole (after acid etching).
Acid etching in the present invention：Performed by GB266-91：Specifically, coarse micro-grain sample processing thickness is 18
Mm, surface are ground with grinding machine, and the low power sample ground then is put into the 70 DEG C of technical hydrochloric acid aqueous solution (works
Industry hydrochloric acid：Water=1：1) in, etching time is 15 minutes, is then taken out from aqueous hydrochloric acid solution,
Surface topography is observed after cooling.
Wherein, Fig. 5 is the cross-sectional view of heavy section steel, and a (represents the middle part of heavy section steel, is commonly called as
Waist) it is 310mm, b (representing an end of heavy section steel, be commonly called as long leg) is 174mm, c
(representing another end of heavy section steel, be commonly called as short-leg) is 125mm, and d (represents heavy section steel
One end, it is commonly called as the thickness of long leg) it is 12mm, e (represents the middle part of heavy section steel, is commonly called as
The thickness of waist) it is 12mm, f (represents another end of heavy section steel, be commonly called as the thickness of short-leg)
For 18mm.
Table 1
As shown in Table 1, strand non-stop layer defect of the invention, not cracked and hole phenomenon,
And the atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability of the present invention improves, the intensity such as Rel and Rm of steel
There is larger improvement.As can be seen here, the present invention provides for the large-scale production of atmosphere corrosion resistance structural steel
Technical conditions.
Table 2
The preferred embodiment of the present invention described in detail above, still, the present invention are not limited to above-mentioned reality
The detail in mode is applied, can be to the technical side of the present invention in the range of the technology design of the present invention
Case carries out a variety of simple variants, and these simple variants belong to protection scope of the present invention.
It is further to note that each particular technique described in above-mentioned embodiment is special
Sign, in the case of reconcilable, can be combined by any suitable means, in order to avoid need not
The repetition wanted, the present invention no longer separately illustrate to various combinations of possible ways.
In addition, various embodiments of the present invention can be combined randomly, as long as its
Without prejudice to the thought of the present invention, it should equally be considered as content disclosed in this invention.
Claims (10)
- A kind of 1. atmosphere corrosion resistance structural steel molten steel, it is characterised in that on the basis of the gross weight of molten steel, Molten steel consists of the following composition：0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60 % Mn, 0.30%-0.40% Cu, 0.20%-0.30% Ni, 3.5%-5.0% Cr, 0.16%-0.20% V, 0.01%-0.015% Nb, 0.021%-0.030% N, less In 0.030% P, the S no more than 0.020%, remaining is inevitable impurity and Fe.
- 2. molten steel according to claim 1, wherein, the temperature of molten steel is 1535-1565 DEG C, with On the basis of the gross weight of molten steel, the Als contents in molten steel are 0.01%-0.03%.
- 3. a kind of atmosphere corrosion resistance structural steel, it is characterised in that the atmosphere corrosion resistance structural steel will by right Molten steel described in 1 or 2 is asked to carry out continuous casting, rolling.
- 4. atmosphere corrosion resistance structural steel according to claim 3, wherein, the temperature of the continuous casting is 1535-1565 DEG C, and carry out slow cooling to room temperature after the square billet obtained after continuous casting is cooled into 500-700 DEG C and obtain To strand and then being rolled, wherein, slow cooling speed is 5-100 DEG C/h, preferably 10-30 DEG C/h；Roll The finishing temperature of system is 700-950 DEG C.
- 5. a kind of production method of atmosphere corrosion resistance structural steel, it is characterised in that this method includes：(1) converter smelting and deoxidation alloying：Converter smelting and deoxygenation are carried out after molten iron is pre-processed Aurification, wherein, controlling the outbound molten steel component of converter smelting and deoxidation alloying includes：C、Si、Mn、 Cr, Cu, Ni, P and S, and on the basis of the gross weight of molten steel, Cu contents be 0.30%-0.40%, Ni contents are 0.20%-0.30%, P≤0.03% and S≤0.02%；(2) LF stoves refine：Molten steel obtained by step (1) is refined in LF stoves；Wherein, jointly controlled by step (1) and step (2) so that the outbound molten steel of LF stoves respectively into Weight content is divided to meet：C content is 0.01%-0.09%, and Si contents are 0.15%-0.35%, Mn contents For 0.30%-0.60%, Cr contents are 3.5%-5.0%, and Cu contents are 0.30%-0.40%, and Ni contents are 0.20%-0.30%, V content 0.16%-0.20%, Nb content are 0.01%-0.015%, and N contains Measure as 0.021%-0.030%, P≤0.03% and S≤0.02%；(3) continuous casting：Molten steel obtained by step (2) is subjected to continuous casting and obtains strand；(4) roll：Rail will be rolled into after heating strand obtained by step (3).
- 6. the method according to claim 11, wherein,In step (1), the outbound molten steel temperature for controlling converter smelting and deoxidation alloying is 1550-1580℃；In step (2), it is 1570-1600 DEG C to control the outbound molten steel temperature of LF stoves.
- 7. the method according to claim 11, wherein,In step (1), in the outbound molten steel for controlling converter smelting and deoxidation alloying, with the total of molten steel On the basis of weight, Als contents are 0.02%-0.05%；In step (2), control in the outbound molten steel of LF stoves, on the basis of the gross weight of molten steel, Als contains Measure as 0.01%-0.03%.
- 8. the method according to claim 11, wherein,In step (3), Continuous Cast Molten Steel Temperature is 1535-1565 DEG C, and the square billet obtained after continuous casting is cooled down Slow cooling to room temperature is carried out after to 500-700 DEG C and obtains the strand, wherein, slow cooling speed is 5-100 DEG C/h, Preferably 10-30 DEG C/h；In step (4), temperature after heating is 1100-1250 DEG C, and finishing temperature is 700-950 DEG C.
- 9. according to the method for claim 5, wherein, in step (2), the refining of LF stoves includes：I) optionally, the slag on molten steel surface obtained by step (1) is reduced with aluminum shot, aluminum shot Dosage is 0-1.5kg/ ton steel；Ii) with carbon line, ferrosilicon, ferromanganese and ferrochrome to C, Si, Mn in molten steel obtained by step (1) It is adjusted with the content of Cr compositions so that meeting outbound molten steel requirement；Iii) optionally, adjustment Als contents to meet outbound molten steel requirement；Iiii) it is outbound make it that Nb contents, N content and V content meet for progress vanadium, nitrogen and niobium alloy Molten steel requirement.
- 10. the method in claim 5-9 described in any one produces obtained atmosphere corrosion resistance structural steel, On the basis of the gross weight of atmosphere corrosion resistance structural steel, consist of the following composition：0.01%-0.09% C, 0.15%-0.35% Si, 0.30%-0.60% Mn, 0.30%-0.40% Cu, 0.20%-0.30 % Ni, 3.5%-5.0% Cr, 0.16%-0.20% V, 0.01%-0.015% Nb, 0.021%-0.030% N, the P no more than 0.030%, the S no more than 0.020%, remaining For inevitable impurity and Fe；Wherein, Rel >=475MPa of atmosphere corrosion resistance structural steel, Rm≥650MPa。
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