CN107587063A - A kind of nitrogen atmosphere corrosion resistance structural steel molten steel of titanium containing vanadium and atmosphere corrosion resistance structural steel and its production method - Google Patents
A kind of nitrogen atmosphere corrosion resistance structural steel molten steel of titanium containing vanadium and atmosphere corrosion resistance structural steel 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 contains：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, 2.0% 3.5% Cr, 0.16% 0.20% V, 0.01% 0.015% Nb, 0.005% 0.030% Ti, 0.004% 0.008% N, the P no more than 0.030% and the S no more than 0.020%.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
Continuous casting, rolling is carried out the present invention relates to a kind of atmosphere corrosion resistance structural steel molten steel and using the molten steel of the present invention
Atmosphere corrosion resistance structural steel, and a kind of production method of atmosphere corrosion resistance structural steel and the atmospheric corrosion resistance type that is obtained by this method
Steel.
Background technology
Weather resisting steel, it is a kind of highly important steel, its weather-resistance is 2-8 times of ordinary steel, is applied
Dress property improves 1.5-10 times.Because weather resisting steel is relative to the validity of the weather-resistant of ordinary steel, relative to stainless
Steel has good economy again, so being developed rapidly in countries in the world, the various outdoor steel constructions used, railway carriage
And bridge be its application scope.
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, pass through on the basis of 09CuPCrNi
Phosphorus is reduced, and improves manganese content, have developed the steel Q450NQR1 (namely 09MnCuCrNi) of sheet material class, Q450NQR1 is in sheet material
Controlled rolling and controlled cooling is used during rolling, so that it may obtain the weather resisting steel that yield strength is not less than 450MPa.And it is directed to section bar not
The productive prospecting of energy controlled rolling and controlled cooling, by reducing 09CuPCrNi phosphorus contents and improving manganese content, and add vanadium and carry out microalloy
Change, have developed the steel YQ450NQR1 (namely 09MnCuCrNiV) of section bar class, do not bent in type steel production line by controlled rolling and controlled cooling
More than 450MPa can also be reached by taking intensity.
After 2010, preferably to improve the atmospheric corrosion resistance ability of steel, sheet material types of steel is by further improving in steel
Chromium content, have developed the S450EW that chromium content is up to 2.5%-5.5%, atmospheric corrosion resistance be even more Q450NQR1 it
On, the kind has possessed large-scale production ability at present.But as the steel of section bar class, improve the square continuous casting produced after chromium content
Base, it there are obvious central defect (predominantly centre burst and central pipe), and the intensity index of final shaped steel
Do not reach the effect of sheet material class steel, 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 atmosphere corrosion resistance structural steel strand of high intensity
Center mass and can improve hardness of steel index atmosphere corrosion resistance structural steel molten steel and a kind of 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 atmosphere corrosion resistance structural steel steel
Water, on the basis of the gross weight of molten steel, molten steel contains：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, 2.0%-3.5% Cr, 0.16%-0.20%
V, 0.005%-0.030% Ti, 0.01%-0.015% Nb, 0.004%-0.008% N, no more than 0.030%
The P and S no more than 0.020%.
According to the second aspect of the invention, the invention provides a kind of atmosphere corrosion resistance structural steel, the atmospheric corrosion resistance type
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
Including：
(1) converter smelting and deoxidation alloying：Converter smelting and deoxidation alloying are carried out after molten iron is pre-processed, wherein,
The outbound molten steel component of control converter smelting and deoxidation alloying includes：C, Si, Mn, Cr, Cu, Ni, P and S, and with the total of molten steel
On the basis of weight, Cu contents are that 0.30%-0.40%, Ni content 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 each Ingredients Weight content of the outbound molten steel of LF stoves meets：
C content is 0.01%-0.09%, and Si contents are 0.15%-0.35%, and Mn contents are 0.30%-0.60%, and Cr contents are
2.0%-3.5%, Cu content are 0.30%-0.40%, and Ni contents are 0.20%-0.30%, V content 0.16%-0.20%,
Ti contents are 0.005%-0.030%, and Nb contents are 0.01%-0.015%, N content 0.004%-0.008%, 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, obtained atmospheric corrosion resistance is produced the invention provides the method according to the present invention
Shaped steel, on the basis of the gross weight of atmosphere corrosion resistance structural steel, contain：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, 2.0%-3.5% Cr, 0.16%-
0.20% V, 0.005%-0.030% Ti, 0.01%-0.015% Nb, 0.004%-0.008% N, are not more than
The 0.030% P and S no more than 0.020%, wherein, atmosphere corrosion resistance structural steel Rel >=450MPa, Rm >=630MPa.
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 center contracting
Hole, thus can improve the quality of the high atmosphere corrosion resistance structural steel strand of high intensity, and strand qualification rate can increase substantially；It is and final
Obtained atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability 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, titanium, nitrogen and
Niobium, a large amount of V (C, N), Ti (C, N) and Nb (C, N) particle can be formed, these particles can refine the crystal grain of strand, prevent strand tree
The development of dendrite, so as to avoid strand center cracked and hole.In addition, these V (C, N), Ti (C, N) and Nb (C, N) matter
Point can dissolve in austenite mostly in subsequent heating strand, and particle separates out again in rolling of sectional iron and cooling procedure after rolling,
Precipitation strength effect is produced, improves the intensity of steel.So that the present invention can not only improve strand center mass, and can carry
The strength character and decay resistance of high atmosphere corrosion resistance structural 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 is for providing a further understanding of the present invention, and a part for constitution instruction, with following tool
Body embodiment is used to explain the present invention together, but is not construed as limiting the invention.In the accompanying drawings：
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 is it should be appreciated that described herein specific
Embodiment 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, these scopes or
Value should be understood to comprising the value close to these scopes or value.For number range, between the endpoint value of each scope, respectively
It can be combined with each other between the endpoint value of individual scope and single point value, and individually between point value and obtain one or more
New number range, these number ranges should be considered as specific open herein.
As it was previously stated, the invention provides a kind of atmosphere corrosion resistance structural steel molten steel, on the basis of the gross weight of molten steel, molten steel
Contain：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, 2.0%-3.5% Cr, 0.16%-0.20% V, 0.005%-0.030% Ti,
0.01%-0.015% Nb, 0.004%-0.008% N, the P no more than 0.030% and the S no more than 0.020%.Using
Strand (alternatively referred to as continuous casting billet) center mass that the molten steel continuous casting of aforementioned component obtains is improved, Cross Section of CC Billet center
(after acid etching) basic non-stop layer crackle and hole.
According to the molten steel of the present invention, in addition to mentioned component, 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 point
Discovery is analysed and puts into practice to 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 the increase of C, Si, Mn component in steel, the intensity of steel
Significantly rise, but the toughness of steel and weldability decline therewith, and shaped steel is usually required that with good weldability and toughness, institute
With application claims C controls in the range of 0.01%-0.09%, Si is controlled in the range of 0.15%-0.35%, and Mn controls exist
In the range of 0.30%-0.60%.
P is one of element for improving steel atmospheric corrosion resistance ability, and the P content of Cu-P systems weather resisting steel is reachable
0.07%-0.12%.But P is the element for improving black brittleness transition temperature again, is unfavorable for the low temperature impact properties of steel, makes simultaneously
Low temperature impact properties containing atmosphere corrosion resistance structural steels such as Cr, Ni, Cu decline to a great extent, and therefore, limit 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, present invention control Cu in 0.30%-0.40%,
Cr is in 2.0%-3.5%, and 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, and the point must take other technical measures to give to overcome.
To overcome Cr contents to improve the defects of bringing, the present invention adds V, Ti, N, Nb element and solved in molten steel
The technical problem of the present invention, speculate that these elements can improve strand center mass for the present inventor below, and improve
The possible cause of the intensity of steel：
In the cooling procedure of strand, strand containing Ti can separate out Ti (C, N) particle, prevent the development of strand dendrite, drop
The low possibility for forming thick dendrite, while the degree that strand selects part to crystallize also reduces, so as to improve strand internal structure,
Avoid the formation of centre burst and hole.It can also be found in addition, in the heating process of follow-up steel billet, when more than 1250 DEG C
Ti (C, N) particle of austenite is not dissolved in, can prevent growing up for austenite crystal.Therefore, add a certain amount of Ti be it is useful,
But the square frame-shaped that excessive titanium easily forms more than 30 μm is mingled with, and scratches steel matrix, so the Ti elements of addition are not easy excessively, control
System is in 0.005%-0.030% than advantageous.
V can also form V (C, N) particle, and the development of strand dendrite can be also prevented in the cooling procedure of strand, reduce shape
Into the possibility of thick dendrite, while the degree that strand selects part to crystallize also reduces, and so as to improve strand internal structure, avoids
The formation of centre burst and hole.In addition, in 2 Mo Steel Slab during Heating Process, V (C, N) particles start to be dissolved in austenite at 600 DEG C or so
In, 900 DEG C -1000 DEG C are completely dissolved in austenite, are 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.
N content deficiency, formation TiC and VC quantity is on the high side, and TiN and VN quantity are on the low side, is that unfavorable Ti and V performance is beneficial
Effect, therefore the present invention need to control N in the range of 0.004%-0.008%.N can be brought into steel with furnace charge and alloy, liquid
Metal can also from air suction part N, the residual N content of usual BOF smelting steel is 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.
Nb is also that can form Nb (C, N) particle, and the development of strand dendrite can be also prevented in the cooling procedure of strand,
The possibility for forming thick dendrite is reduced, while the degree that strand selects part to crystallize also reduces, so as to improve strand internal junction
Structure, avoid the formation of centre burst and hole.In addition, in 2 Mo Steel Slab during Heating Process, Nb (C, N) particle can also be completely dissolved in austenite
In, and can just be separated out in rolling from austenite, Controlled Cooling is realized, the significant ferrite crystal grain for refining steel, so as to
Improve the obdurability of steel.
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, using the steel of the aforementioned component of the present invention
Water and control molten steel temperature be 1535-1565 DEG C, can directly carry out continuous casting, the center mass for the strand that continuous casting obtains can
Further 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 is by institute of the present invention
The molten steel stated carries out continuous casting, rolling.
According to the atmosphere corrosion resistance structural steel of the present invention, the temperature (or being Continuous Cast Molten Steel Temperature) of preferably described continuous casting is
1535-1565 DEG C, when the molten steel temperature within the range when, without further enter trip temperature adjustment, can directly carry out
Continuous casting.
According to the present invention atmosphere corrosion resistance structural steel, preferably by the square billet obtained after continuous casting be cooled to 500-700 DEG C it is laggard
Row slow cooling to room temperature obtains strand and then rolled, wherein, preferably slow cooling speed is 5-100 DEG C/h, more preferably 10-30
℃/h。
Mode of the invention to slow cooling is without particular/special requirement, as long as meeting that the mesh of the present invention can be achieved in foregoing slow cooling speed
's.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 the slow cooling to reduce cooldown rate.
It was found by the inventors of the present invention that in slow cooling temperature control, excessive temperature adds more than burial pit, such as 800 DEG C
When, strand or austenite structure, without ferromagnetism, it is unfavorable for the safety operation of ferromagnetic class crane, therefore regulation is put into slow cooling
Temperature is cheated not above 700 DEG C.The martensite transformation temperature of usual steel is high in martensite transformation temperature scope at 400 DEG C or so
Even if the cooling velocity of the strand steel containing chromium is not reaching to the temperature Rate that martensitic traoformation occurs, faster cooling velocity also can
Cause casting billet surface and the internal a large amount of crackles of generation, therefore, it is specified that the temperature for being put into burial pit 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 the atmospheric corrosion resistance that can obtain meeting application claims
Shaped steel, the production method of the invention to the atmosphere corrosion resistance structural steel is without particular/special requirement, according to the present invention, in order to further improve
Strand center mass, improve strand central defect, and improve the strength character and decay resistance of steel, preferably of the invention is resistance to big
The production method of gas corrosion shaped steel includes：
(1) converter smelting and deoxidation alloying：Converter smelting and deoxidation alloying are carried out after molten iron is pre-processed, wherein,
The outbound molten steel component of control converter smelting and deoxidation alloying includes：C, Si, Mn, Cr, Cu, Ni, P and S, and with the total of molten steel
On the basis of weight, Cu contents are that 0.30%-0.40%, Ni content 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 each Ingredients Weight content of the outbound molten steel of LF stoves meets：
C content is 0.01%-0.09%, and Si contents are 0.15%-0.35%, and Mn contents are 0.30%-0.60%, and Cr contents are
2.0%-3.5%, Cu content are 0.30%-0.40%, and Ni contents are 0.20%-0.30%, V content 0.16%-0.20%,
Ti contents are 0.005%-0.030%, and Nb contents are 0.01%-0.015%, N content 0.004%-0.008%, 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 has found by long-term theory analysis and practice, because Cu and Ni and O affinity is small, very not
It is oxidized easily, when converter smelting process adds, recovery rate just can reach 100%, therefore be arrived in the control of the step of converter procedure one
Position, that is, Cu and Ni is controlled in the range of 0.30%-0.40% and 0.20%-0.30%, to be subsequently no longer adjusted respectively.
With the method for the invention it is preferred in step (1), the outbound molten steel temperature of converter smelting and deoxidation alloying is controlled
For 1550-1580 DEG C.
With the method for the invention it is preferred in step (1), in the outbound molten steel for controlling converter smelting and deoxidation alloying,
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) in 0.02%-0.05% scopes
Interior, it is 1550-1580 DEG C to control converter tapping liquid temperature degree.Als is controlled to allow for rear portion in 0.02-0.05% scopes herein
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 is general
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%.
With the method for the invention it is preferred in step (2), it is 1570-1600 DEG C to control the outbound molten steel temperature of LF stoves.
With the method for the invention it is preferred in step (2), control in the outbound molten steel of LF stoves, using the gross weight of molten steel as base
Standard, 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), by the square billet obtained after continuous casting be cooled to 500-700 DEG C it is laggard
Row slow cooling to room temperature 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 enter according to conventional steps
OK, as long as its technological parameter disclosure satisfy that the preferred requirement of the present invention can preferably realize 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 the present invention, preferred steps
(2) in, the refining of LF stoves includes：
I) optionally, the slag on molten steel surface obtained by step (1) is reduced with aluminum shot, the dosage of aluminum shot is 0-
1.5kg/ ton steel；
Ii) content of C, Si, Mn and Cr composition in molten steel obtained by step (1) is entered with carbon line, ferrosilicon, ferromanganese and ferrochrome
Row adjustment to meet outbound molten steel requirement；
Iii) optionally, adjustment Als contents to meet outbound molten steel requirement；
Iiii) carrying out titanium, vanadium, nitrogen, niobium alloy causes Ti contents, N content, V content and Nb contents to meet outbound molten steel
It is required that.
As it was previously stated, produce obtained atmosphere corrosion resistance structural steel the invention provides the method according to the present invention.
According to the atmosphere corrosion resistance structural steel of the present invention, preferably on the basis of the gross weight of atmosphere corrosion resistance structural steel, contain：
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, 2.0%-3.5% Cr, 0.16%-0.20% V, 0.005%-0.030% Ti,
0.01%-0.015% Nb, 0.004%-0.008% N, the P no more than 0.030% and the S no more than 0.020%.
According to the atmosphere corrosion resistance structural steel of the present invention, in addition to mentioned component, remaining is inevitable impurity and Fe.
According to the Rel >=450MPa, preferably 450- of the atmosphere corrosion resistance structural steel, preferably atmosphere corrosion resistance structural steel of the present invention
485MPa。
According to the Rm >=630MPa, preferably 630- of the atmosphere corrosion resistance structural steel, preferably atmosphere corrosion resistance structural steel of the present invention
655MPa。
A kind of tool of the atmosphere corrosion resistance structural steel of preferred embodiment production present invention according to the present invention is described below
Body implementation steps, atmosphere corrosion resistance structural steel is produced according to the step in embodiment (i.e. steel 1-4 of the present invention in table)：
Key step includes：Converter smelting and deoxidation alloying → LF stoves refining → continuous casting → heating strand → 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 targe are in molten steel：C 0.01%-
0.09%th, Si 0.15%-0.35%, Mn 0.30%-0.60% and Cr 2.0%-3.5%.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, when converter smelting process adds, recovery rate 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 0.20%-
In the range of 0.30%, subsequently no longer it is adjusted.
Converter uses Al deoxidization techniques, and controls Als (dissolved aluminum) in the range of 0.02%-0.05%, and control converter goes out
Molten steel temperature is 1550-1580 DEG C.Als is controlled herein in 0.02-0.05% scopes, allow 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 is typically in 0.010%-
In the range of 0.02%, by a large amount of it was verified that the Als of the strand after being cooled down after last continuous casting steel machine can be in 0.01-
In the range of 0.03%.
B LF stoves refine
Molten steel optionally includes adding the step of aluminum shot reduces slag, aluminum shot addition is when LF stoves refine
0-1.5kg/ ton steel；
After LF stove electrical heating, micro adjustment is carried out to C, Si, Mn and Cr composition with carbon line, ferrosilicon, ferromanganese and ferrochrome, adjusted
Scope is respectively in 0.01%-0.09% (C), 0.15%-0.35% (Si), 0.30%-0.60% (Mn) and 2.0%-3.5%
(Cr) in.
After being finely tuned to C, Si, Mn and Cr, Als in sampling analysis molten steel, adjustment Als contents are 0.01%-0.03%；Such as
Als is less than 0.02%, then needs that Als is adjusted into 0.025% or so using the method for adding aluminum shot or feeding aluminum steel, can protect
The Als of strand is controlled in the range of 0.01%-0.03% after card continuous casting cast steel.It is to examine 0.025% or so to control Als herein
Consider rear portion continuous casting steel machine process and there are Als and be oxidized to Al2O3Phenomenon, by a large amount of it was verified that continuous casting steel machine process
Strand Als oxidation is in the range of 0.005-0.015%.
After adjusting Als, ferrotianium, ferrocolumbium, VN alloy (VN12, VN14 and VN16) are added, is made in molten steel
Ti is controlled in the range of 0.005%-0.030%, and V is controlled in the range of 0.16%-0.20%, and N is controlled in 0.004%-
In the range of 0.008%, Nb is controlled in the range of 0.010%-0.015%, and it is 1570-1600 to control the outbound molten steel temperature of LF stoves
℃。
C continuous castings
Chemical composition (percentage by weight) is 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, 2.0%-3.5% Cr, 0.16%-0.20%
V, 0.005%-0.030% Ti, 0.01%-0.015% Nb, 0.004%-0.008% N, no more than 0.030%
P and S no more than 0.020% molten steel carries out continuous casting, and control continuous casting steel machine liquid temperature degree is in the range of 1535-1565 DEG C.
Strand is put into burial pit and delayed in cast molding on continuous casting casting machine and when being cooled in the range of 500-700 DEG C
It is cold, go out burial pit after slow cooling to room temperature, slow cooling speed is 5-100 DEG C/h, preferably 10-30 DEG C/h.Check that strand breaks after going out hole
Face quality, 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 more than burial pit, such as 800 DEG C
When, strand or austenite structure, without ferromagnetism, it is unfavorable for the safety operation of ferromagnetic class crane, therefore regulation is put into slow cooling
Temperature is cheated not above 700 DEG C.The martensite transformation temperature of usual steel is high in martensite transformation temperature scope at 400 DEG C or so
Even if the cooling velocity of the strand steel containing chromium is not reaching to the temperature Rate that martensitic traoformation occurs, faster cooling velocity also can
Cause casting billet surface and the internal a large amount of crackles of generation, therefore, it is specified that the temperature for being put into burial pit 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 carries out strand rolling to shaped steel
System, finishing temperature control is in the range of 700 DEG C -950 DEG C, and the shaped steel being finally rolled into is by the way of natural air cooling, you can
To Rel >=450MPa, Rm >=630MPa, relatively corrosive rate (relative to YQ450NQR1 high-strength weather resisting steels) is 65%-
The 70% high atmosphere corrosion resistance structural steel of high 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 be using it is foregoing " converter smelting and deoxidation alloying → LF stoves refining →
The chemical constituent of continuous casting → heating strand → shape rolling mill rolling " technique productions steel of the present invention, wherein, converter smelting and deoxygenation
The main control parameters of aurification → LF stoves refining → continuous casting → heating strand → shape rolling mill rolling are shown in Table 2；
Compared steel 1 in table 1 is to use foregoing " converter smelting and deoxidation alloying → LF stoves refining → continuous casting → strand
Heating → shape rolling mill rolling " technique, C, Si, Mn, Cr, Ni and Cu chemical composition of production and base steel this identical pair of the present invention
Compare steel；
Compared steel 2 in table 1 is to use foregoing " converter smelting and deoxidation alloying → LF stoves refining → continuous casting → strand
Heating → shape rolling mill rolling " technique, the chemical composition of the existing YQ450NQR1 high strength atmospheric corrorsion resistant section steels of production；
The assay method of Rel and Rm in table 1 are GB/T228-2002 (metal material tensile testing at ambient temperature)；
The test method of relatively corrosive rate presses the former Ministry of Railways " TB/T2375-93 " (railway weathering steel period soaking corrosion in table 1
Corrosion tests) as defined in method measure, its specific location parameter is：Test sample is processed into 60mm × 40mm × 4mm square
Shape, it is desirable to which the surface roughness of largest face is 3.2 μm；Temperature is 45 ± 2 DEG C；Humidity is：70 ± 5%RH；Each cycle period
For 60 ± 3min (wherein infiltrating time is 12 ± 1.5min)；Cycle period is 75h；Specimen surface maximum temperature is 70 after baking
±10℃；Solution is：(1.0±0.05)×10-2mol/l NaHSO3Solution.The basic steel grade of relatively corrosive rate is chosen to be
YQ450NQR1 (compared steel 2) high strength atmospheric corrorsion resistant section steel, i.e., YQ450NQR1 high strength atmospheric corrorsion resistant section steels is relative
Rate of corrosion is 100%.
The sampling point and sampling state of intensity index and relatively corrosive rate measure sample are in table 1：Using in the present invention
The heavy section steel that described technique and parameter are produced, 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 coupon 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, as seen from Figure 1,
There is 30mm crackle+hole pattern in the centre of compared steel 1.
Wherein, Fig. 2 is to use the sectional drawing after rolling of sectional iron a time after the continuous casting billet heating of compared steel 1, can be with by Fig. 2
It was 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 elements
Total amount is also below the alloy total amount of chemical composition in compared steel 1, therefore the Cross Section of CC Billet center after acid etching does 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 is found that continuous casting billet breaks
Face 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 18mm, surface grinding machine
Grind, the low power sample ground is then put into the 70 DEG C of technical hydrochloric acid aqueous solution (technical hydrochloric acids：Water=1：1) in, etching time
For 15 minutes, 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 (representing the middle part of heavy section steel, be commonly called as waist) is
310mm, b (representing an end of heavy section steel, be commonly called as long leg) are 174mm, and c (represents another end of heavy section steel, custom
Short-leg) it is referred to as 125mm, d (representing an end of heavy section steel, be commonly called as the thickness of long leg) is 12mm, and e (represents heavy section steel
Middle part, be commonly called as the thickness of waist) be 12mm, f (representing another end of heavy section steel, be commonly called as the thickness of short-leg) is
18mm。
Table 1
As shown in Table 1, strand non-stop layer defect of the invention, not cracked and hole phenomenon, and the present invention
Atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability improve, the intensity such as Rel and Rm of steel have larger improvement.As can be seen here,
The present invention provides technical conditions for the large-scale production of atmosphere corrosion resistance structural steel.
Table 2
The preferred embodiment of the present invention described in detail above, still, the present invention are not limited in above-mentioned embodiment
Detail, in the range of the technology design of the present invention, a variety of simple variants can be carried out to technical scheme, this
A little simple variants belong to protection scope of the present invention.
It is further to note that each particular technique feature described in above-mentioned embodiment, in not lance
In the case of shield, can be combined by any suitable means, in order to avoid unnecessary repetition, the present invention to it is various can
The combination of energy no longer separately illustrates.
In addition, various embodiments of the present invention can be combined randomly, as long as it is without prejudice to originally
The thought of invention, it should equally be considered as content disclosed in this invention.
Claims (10)
1. a kind of atmosphere corrosion resistance structural steel molten steel, it is characterised in that on the basis of the gross weight of molten steel, molten steel contains：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, 2.0%-3.5% Cr, 0.16%-0.20% V, 0.01%-0.015% Nb, 0.005%-0.030% Ti,
0.004%-0.008% N, the P no more than 0.030% and the S no more than 0.020%.
2. molten steel according to claim 1, wherein, the temperature of molten steel is 1535-1565 DEG C, using the gross weight of molten steel as base
Standard, 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 is as the steel described in claim 1 or 2
Water carries 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 will
The square billet obtained after continuous casting carries out slow cooling to room temperature after being cooled to 500-700 DEG C and obtains strand and then rolled, wherein, slow cooling
Speed is 5-100 DEG C/h, preferably 10-30 DEG C/h；The finishing temperature of rolling 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 deoxidation alloying are carried out after molten iron is pre-processed, wherein, control
The outbound molten steel component of converter smelting and deoxidation alloying includes：C, Si, Mn, Cr, Cu, Ni, P and S, and with the gross weight of molten steel
On the basis of, Cu contents are that 0.30%-0.40%, Ni content 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 each Ingredients Weight content of the outbound molten steel of LF stoves meets：C contains
It is 0.15%-0.35% to measure as 0.01%-0.09%, Si contents, and Mn contents are 0.30%-0.60%, and Cr contents are 2.0%-
3.5%, Cu content are 0.30%-0.40%, and Ni contents are 0.20%-0.30%, V content 0.16%-0.20%, Ti content
For 0.005%-0.030%, Nb contents are 0.01%-0.015%, N content 0.004%-0.008%, 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), it is 1550-1580 DEG C to control the outbound molten steel temperature of converter smelting and deoxidation alloying；
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, on the basis of the gross weight of molten steel, Als contains
Measure as 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 contents are 0.01%-0.03%.
8. the method according to claim 11, wherein,
In step (3), Continuous Cast Molten Steel Temperature be 1535-1565 DEG C, by the square billet obtained after continuous casting be cooled to 500-700 DEG C it is laggard
Row slow cooling to room temperature 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, the dosage of aluminum shot is 0-1.5kg/ tons
Steel；
Ii) content of C, Si, Mn and Cr composition in molten steel obtained by step (1) is adjusted with carbon line, ferrosilicon, ferromanganese and ferrochrome
It is whole so that meeting outbound molten steel requirement；
Iii) optionally, adjustment Als contents to meet outbound molten steel requirement；
Iiii) carrying out titanium, vanadium, nitrogen and niobium alloy causes Ti contents, N content, V content and Nb contents to meet that outbound molten steel will
Ask.
10. the method in claim 5-9 described in any one produces obtained atmosphere corrosion resistance structural steel, with atmospheric corrosion resistance type
On the basis of the gross weight of steel, contain：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, 2.0%-3.5% Cr, 0.16%-0.20% V, 0.005%-
0.030% Ti, 0.01%-0.015% Nb, 0.004%-0.008% N, P no more than 0.030% and it is not more than
0.020% S, wherein, Rel >=450MPa of atmosphere corrosion resistance structural steel, Rm >=630MPa.
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| CN101994064A (en) * | 2009-08-18 | 2011-03-30 | 宝山钢铁股份有限公司 | Weathering steel with yield strength of 550MPa level and manufacturing method thereof |
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