CN106676418A - Atmosphere corrosion resisting profile steel liquid containing niobium and nitrogen, atmosphere corrosion resisting profile steel and production method of atmosphere corrosion resisting profile steel - Google Patents
Atmosphere corrosion resisting profile steel liquid containing niobium and nitrogen, atmosphere corrosion resisting profile steel and production method of atmosphere corrosion resisting profile steel Download PDFInfo
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Abstract
The invention relates to the field of steelmaking and particularly provides atmosphere corrosion resisting profile steel liquid. On the criterion of the total weight of the steel liquid, the steel liquid comprises 0.01-0.09% of C, 0.15-0.35% of Si, 0.30-0.60% of Mn, 0.30-0.40% of Cu, 0.20-0.30% of Ni, 2.0-3.5% of Cr, 0.16-0.20% of V, 0.005-0.030% of Ti, 0.01-0.015% of Nb, 0.021-0.030% of N, no more than 0.030% of P and no more than 0.020% of S. The invention provides atmosphere corrosion resisting profile steel and a production method thereof. When the steel liquid is adopted for continuous casting, the center quality of cast blanks can be improved, center cracking and center line shrinkage are avoided, and thus the quality of profile steel cast blanks with high strength and high atmosphere corrosion resistance can be improved, and the qualification rate of cast blanks can be greatly increased. In addition, the finally obtained atmosphere corrosion resisting profile steel has good atmosphere corrosion resistance and higher strength.
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 a kind of atmosphere corrosion resistance structural steel production method and by the party
The atmosphere corrosion resistance structural steel that method is obtained.
Background technology
Weather resisting steel, is the highly important steel of a class, and its weather-resistance is ordinary steel
2-8 times, coating improves 1.5-10 times.Because weather resisting steel is relative to the anti-air corruption of ordinary steel
The validity of erosion, has good economy, so having obtained fast in countries in the world again relative to stainless steel
Speed development, the various outdoor steel constructions for using, 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 simplified version 09Cu of Cor Ten A, the yield strength of two kinds under hot-rolled condition be generally
300-450MPa。
It is the low temperature impact properties of the yield strength and steel for improving steel, in 09CuPCrNi after 2000
On the basis of by reducing phosphorus, and improve manganese content, have developed sheet material class steel Q450NQR1 (
That is 09MnCuCrNi), Q450NQR1 adopts controlled rolling and controlled cooling in plate rolling, so that it may obtain surrender strong
Degree is not less than the weather resisting steel of 450MPa.And the productive prospecting that section bar is unable to controlled rolling and controlled cooling is directed to,
Microalloying is carried out by reducing 09CuPCrNi phosphorus contents and improving manganese content, and add vanadium, is developed
The steel YQ450NQR1 (namely 09MnCuCrNiV) of section bar class, in type steel production line controlled rolling is not passed through
Controlling cold yield strength can also reach more than 450MPa.
It is the atmospheric corrosion resistance ability for preferably improving steel after 2010, sheet material types of steel is by further
Chromium content in steel is improved, the S450EW that chromium content is up to 2.5%-5.5%, atmospheric corrosion resistance is have developed
Performance is even more on Q450NQR1, and at present the kind has possessed large-scale production ability.But as type
The steel of material class, improves the square continuous casting billet produced after chromium content, there are obvious central defect (main
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
Really, therefore, possess the section bar class steel for having more preferable atmospheric corrosion resistance ability be also constantly in research and development in.
The content of the invention
The technical problem to be solved is 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 of hardness of steel index can be improved
Plant 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
Erosion shaped steel molten steel, on the basis of the gross weight of molten steel, molten steel contains:The C of 0.01%-0.09%,
The Cu of the Mn of the Si of 0.15%-0.35%, 0.30%-0.60%, 0.30%-0.40%,
The V of the Cr of the Ni of 0.20%-0.30%, 2.0%-3.5%, 0.16%-0.20%, 0.005%-0.030%
Ti, the Nb of 0.01%-0.015%, the N of 0.021%-0.030%, no more than 0.030% P
No more than 0.020% S.
According to the second aspect of the invention, the invention provides a kind of atmosphere corrosion resistance structural steel, described resistance to big
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,
The 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 refining:Step (1) gained molten steel 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 2.0%-3.5%, and Cu contents are 0.30%-0.40%, and Ni contents are
0.20%-0.30%, V content is 0.16%-0.20%, and Ti contents are 0.005%-0.030%, Nb
Content is 0.01%-0.015%, and N content is 0.021%-0.030%, P≤0.03% and S≤0.02%;
(3) continuous casting:Step (2) gained molten steel is carried out into continuous casting and obtains strand;
(4) roll:Rail will be rolled into after step (3) gained heating strand.
According to the fourth aspect of the invention, the invention provides according to the method for the present invention production obtain it is resistance to
Atmospheric corrosion shaped steel, on the basis of the gross weight of atmosphere corrosion resistance structural steel, contains:0.01%-0.09%'s
The Cu of the Mn of the Si of C, 0.15%-0.35%, 0.30%-0.60%, 0.30%-0.40%,
The V of the Cr of the Ni of 0.20%-0.30%, 2.0%-3.5%, 0.16%-0.20%, 0.005%-0.030%
Ti, the Nb of 0.01%-0.015%, the N of 0.021%-0.030%, no more than 0.030% P
No more than 0.020% S, wherein, atmosphere corrosion resistance structural steel Rel >=465MPa, Rm >=640MPa.
The center mass of strand can be improved using the molten steel continuous casting of the present invention, it is to avoid centre burst occur
And central pipe, the quality of the high atmosphere corrosion resistance structural steel strand of high intensity thus can be improved, strand is closed
Lattice rate can be increased substantially;And the atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability for finally giving is good
And possess higher strength character.
The present inventor speculate, be due to the present invention add in the high weather resisting steel of high intensity vanadium,
Titanium, niobium and nitrogen, can form a large amount of V (C, N), Ti (C, N) and Nb (C, N) particle, this
A little particles can refine the crystal grain of strand, prevent the development of strand dendrite, so as to avoid strand center from occurring
Crackle and hole.In addition, these V (C, N), Ti (C, N) and Nb (C, N) particles with
Austenite can be dissolved in heating strand afterwards mostly, particle is again in rolling of sectional iron and the cooling procedure after rolling
Separate out, produce precipitation strength effect, improve the intensity of steel.So that the present invention not only can improve casting
Base center mass, and the strength character and decay resistance of atmosphere corrosion resistance structural steel can be improved.
Other features and advantages of the present invention will be described in detail in subsequent specific embodiment part.
Description of the drawings
Accompanying drawing is, for providing a further understanding of the present invention, and to constitute the part of specification, with
Detailed description below 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 adopts the sectional drawing after rolling of sectional iron a time after heating for the continuous casting billet of compared steel 1;
Fig. 3 is the sectional drawing (after acid etching) of the continuous casting billet of compared steel 2;
Fig. 4 is the Cross Section of CC Billet figure (after acid etching) of steel of the present invention 2;
Fig. 5 is the cross-sectional view of heavy section steel.
Specific embodiment
The specific embodiment of the present invention is described in detail below.It should be appreciated that this place is retouched
The specific embodiment stated is merely to illustrate and explains the present invention, is not limited to the present invention.
As it was previously stated, the invention provides a kind of atmosphere corrosion resistance structural steel molten steel, the gross weight with molten steel is
Benchmark, molten steel contains:The Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%'s
The Cr of the Ni of the Cu of Mn, 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.16%-0.20%
V, the Ti of 0.005%-0.030%, the Nb of 0.01%-0.015%, the N of 0.021%-0.030%,
No more than 0.030% P and no more than 0.020% S.Obtained using the molten steel continuous casting of aforementioned component
Strand (alternatively referred to as continuous casting billet) center mass is improved, Cross Section of CC Billet center (after acid etching) base
This non-stop layer crackle and hole.
Molten steel of the 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 analysis and put into practice discovery and obtain.
Specifically, the present inventor has found through 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 and weldability of steel 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 again the element for improving black brittleness transition temperature, is unfavorable for the low of steel
Warm impact property, makes the low temperature impact properties simultaneously containing atmosphere corrosion resistance structural steels such as Cr, Ni, Cu big
Width declines, 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 can improve
The intensity of steel.But because Cu and Ni alloys price is far above Cr alloys, from the economy of steel,
, in 0.30%-0.40%, in 2.0%-3.5%, Ni is in 0.20%-0.30% scopes for Cr for present invention control Cu
It is interior.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 defect brought, the present invention increased in molten steel V, Ti, N,
Nb elements simultaneously solve technical problem of the invention, speculate these for the present inventor below
Element can improve strand center mass, 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 strand dendrite
Development, reduction forms the possibility of thick dendrite, while strand selects the degree that part crystallizes also to reduce,
So as to improve strand internal structure, it is to avoid the formation of centre burst and hole.In addition, in follow-up steel billet
Heating process in, Ti (the C, N) particle for not being dissolved in austenite can also be found when more than 1250 DEG C,
Growing up for austenite crystal can be prevented.Therefore, a certain amount of Ti is added to be useful, but the titanium of excess
Easily form the square frame-shaped more than 30 μm to be mingled with, scratch steel matrix, so the Ti elements of addition are difficult
Excessively, control in 0.005%-0.030% than advantageous.
V can also form V (C, N) particle, and strand dendrite can be also prevented in the cooling procedure of strand
Development, reduction forms the possibility of thick dendrite, while strand selects the degree that part crystallizes also to reduce, from
And improve strand internal structure, it is to 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, separates out in subsequent rolling and roller repairing from austenite, and precipitation strength effect is obvious.
To ensure to obtain a certain amount of V (C, N) particle, the V for adding 0.16%-0.20% is necessary.
Nb also can be to form Nb (C, N) particle, and strand tree can be also prevented in the cooling procedure of strand
The development of dendrite, reduction forms the possibility of thick dendrite, while strand selects the degree that part crystallizes also to subtract
It is little, so as to improve strand internal structure, it is to avoid the formation of centre burst and hole.In addition, strand adds
In thermal process, Nb (C, N) particle also can be completely dissolved in austenite, and just can be from austenite in rolling
Middle precipitation, realizes Controlled Cooling, the ferrite crystal grain of significant refinement steel, so as to improve the tough of steel
Property.
N content is not enough, and the quantity for forming TiC and VC is on the high side, and the quantity of TiN and VN is on the low side, is
Unfavorable Ti and V plays beneficial effect, therefore the present invention need to control N in 0.021%-0.030% scopes
It is interior.N can be brought into steel with furnace charge and alloy, liquid metal can also from air suction part N, generally
The residual N content of BOF smelting steel is about 0.002%-0.008%, electric furnace smelting steel it is residual
N content is stayed to be about 0.006%-0.015%, so in BOF smelting steel, need to be using containing N
Alloy supplement part N.
Molten steel of the invention, preferably on the basis of the gross weight of molten steel, the Als contents in molten steel are
0.01%-0.03%.
Molten steel of the invention, the temperature of preferred molten steel is 1535-1565 DEG C, before the present invention
The temperature stated the molten steel of composition and control molten steel is 1535-1565 DEG C, can directly carry out continuous casting, continuous casting
The center mass of the strand for obtaining 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.
Temperature (or the referred to as Steel Melt for Continuous Casting of atmosphere corrosion resistance structural steel of the invention, the preferably continuous casting
Temperature) be 1535-1565 DEG C, when the molten steel temperature within the range when, without the need for further carrying out
Temperature is adjusted, and can directly carry out continuous casting.
Atmosphere corrosion resistance structural steel of the invention, is preferably cooled to the square billet obtained after continuous casting
Carry out slow cooling to room temperature after 500-700 DEG C to obtain strand and then rolled, wherein, preferred slow cooling speed
For 5-100 DEG C/h, more preferably 10-30 DEG C/h.
The present invention to the mode of slow cooling without particular/special requirement, as long as meeting aforementioned slow cooling speed is capable of achieving this
Bright purpose.For example square billet heap can be entered into burial pit carries out slow cooling.
Then burial pit for example can add a cover and realize described delaying to reduce cooldown rate by setting up melt pit
It is cold.
It was found by the inventors of the present invention that in slow cooling temperature control, excessive temperature adds burial pit,
For example when more than 800 DEG C, strand or austenite structure, without ferromagnetism, are 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 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, speed is cooled down faster
Degree also results in casting billet surface and a large amount of crackles of internal generation, therefore, it is stipulated that it is put into the temperature of burial pit
Degree cannot be below 500 DEG C.
Atmosphere corrosion resistance structural steel of the invention, the finishing temperature of preferred rolling is 700-950 DEG C.
Carrying out continuous casting, rolling using the molten steel with aforementioned component 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, improves strand central defect, and improves the strong of steel
Degree performance and decay resistance, the production method of the atmosphere corrosion resistance structural steel of the preferred present 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 refining:Step (1) gained molten steel 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 2.0%-3.5%, and Cu contents are 0.30%-0.40%, and Ni contents are
0.20%-0.30%, V content is 0.16%-0.20%, and Ti contents are 0.005%-0.030%, Nb
Content is 0.01%-0.015%, and N content is 0.021%-0.030%, P≤0.03%, S≤0.02%;
(3) continuous casting:Step (2) gained molten steel is carried out into continuous casting and obtains strand;
(4) roll:Rail will be rolled into after step (3) gained heating strand.
The present inventor is through long-term theory analysis and puts into practice discovery, because Cu and Ni and O
Affinity is little, is not easy to be oxidized very much, and in converter smelting process plus fashionable recovery rate 100% is just can reach,
Therefore control in place in the step of converter procedure one, 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, preferred converter adopts Al deoxidization techniques, and controls Als (dissolved aluminum) and exist
In the range of 0.02%-0.05%, converter tapping liquid temp is controlled for 1550-1580 DEG C.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 scaling loss amount of the Als of the two-step typically exists
In the range of 0.010%-0.02%, through a large amount of it was verified that the casting after cooling down after last continuous casting steel machine
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), controlling the outbound molten steel temperature of LF stoves is
1570-1600℃。
With the method for the invention it is preferred in step (2), in the outbound molten steel of control LF stoves, with molten steel
Gross weight on the basis of, Als contents be 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 is preferably realized by disclosure satisfy that preferred requirement of the invention
The purpose of the present invention.
In the present invention, after rolling, the method for natural air cooling can be adopted to be cooled down.
The method according to the invention, the LF stoves refining can be carried out according to conventional steps, for this
Bright, in preferred steps (2), the refining of LF stoves includes:
I) optionally, the slag on step (1) gained molten steel surface is reduced with aluminum shot, aluminum shot
Consumption is 0-1.5kg/ ton steel;
Ii) with carbon line, ferrosilicon, ferromanganese and ferrochrome to C, Si, the Mn in step (1) gained molten steel
It is adjusted with the content of Cr compositions so that meeting outbound molten steel requirement;
Iii) optionally, adjust Als contents to cause to meet outbound molten steel requirement;
Iiii) titanium, vanadium, nitrogen and niobium alloy are carried out so that Ti contents, Nb contents, N content and V
Content meets outbound molten steel requirement.
As it was previously stated, the invention provides the atmospheric corrosion resistance type obtained according to method of the present invention production
Steel.
Atmosphere corrosion resistance structural steel of the invention, preferably the gross weight with atmosphere corrosion resistance structural steel is as base
Standard, contains:The Mn of the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%,
The Cr of the Ni of the Cu of 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.16%-0.20%
V, the Ti of 0.005%-0.030%, the Nb of 0.01%-0.015%, 0.021%-0.030%'s
N, no more than 0.030% P and no more than 0.020% S.
Atmosphere corrosion resistance structural steel of the invention, in addition to mentioned component, remaining is inevitably miscellaneous
Matter and Fe.
Atmosphere corrosion resistance structural steel of the invention, the Rel >=465MPa of preferred atmosphere corrosion resistance structural steel,
Preferably 465-510MPa.
Atmosphere corrosion resistance structural steel of the invention, the Rm >=640MPa of preferred atmosphere corrosion resistance structural steel,
Preferably 640-660MPa.
A kind of atmospheric corrosion resistance type for preferred embodiment producing the present invention of the invention is described below
The specific implementation step of steel is resistance to big according to the step production in embodiment (steel 1-4 of the present invention i.e. in table)
Gas corrosion shaped steel:
Key step includes:Converter smelting and deoxidation alloying → LF stove refining → continuous castings → strand
Heating → shape rolling mill is rolled.
Concrete operations content per operation is as follows:
A converter smeltings and deoxidation alloying
During using converter smelting molten steel, the chemical constituent control mesh of C, Si, Mn and Cr in molten steel
It is designated as:C 0.01%-0.09%, Si 0.15%-0.35%, Mn 0.30%-0.60% and Cr
2.0%-3.5%.This operation is only control targe, and the operation such as can not be controlled in target zone,
Follow-up LF stove refining procedures also can adjust.
P≤0.030%, S≤0.020% in control molten steel.
Because the affinity of Cu and Ni and O is little, it is not easy to be oxidized very much, in converter smelting work
Skill adds fashionable recovery rate just to can reach 100%, therefore controls in place, that is, to control in the step of converter procedure one
Cu processed and Ni in the range of 0.30%-0.40% and 0.20%-0.30%, are subsequently no longer carried out respectively
Adjustment.
Converter adopts Al deoxidization techniques, and controls Als (dissolved aluminum) in 0.02%-0.05% scopes
It is interior, converter tapping liquid temp is controlled for 1550-1580 DEG C.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 scaling loss amount of the Als of the two-step typically in the range of 0.010%-0.02%,
Through a large amount of it was verified that the Als of the strand after cooling down after last continuous casting steel machine can be
In the range of 0.01-0.03%.
B LF stoves are refined
Molten steel when LF stoves are refined, optionally including add aluminum shot slag is reduced the step of,
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), in 0.30%-0.60% (Mn) and 2.0%-3.5% (Cr).
After C, Si, Mn and Cr fine setting, Als in sample analysis molten steel adjusts Als contents
For 0.01%-0.03%;As Als is less than 0.02%, then need using addition aluminum shot or feeding aluminum steel
Method Als is adjusted into 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 herein 0.025% or so, allows for rear portion company
Continuous cast steel operation there are Als and be oxidized to Al2O3Phenomenon, through a large amount of it was verified that even
The oxidation of continuous cast steel operation strand Als is in the range of 0.005-0.015%.
After adjustment Als, ferrotianium, ferro-niobium and VN alloy (VN12, VN14 and VN16 are added
), the Ti in molten steel is controlled in the range of 0.005%-0.030%, V is controlled 0.16%
In the range of -0.20%, Nb is controlled in the range of 0.010%-0.015%, and N is controlled 0.021%
In the range of -0.030%, the outbound molten steel temperature of LF stoves is controlled for 1570-1600 DEG C.
C continuous castings
Chemical composition (percentage by weight) for 0.01%-0.09% C, 0.15%-0.35% Si,
Ni, 2.0%-3.5% of Cu, 0.20%-0.30% of Mn, 0.30%-0.40% of 0.30%-0.60%
Cr, 0.16%-0.20% V, 0.005%-0.030% Ti, 0.01%-0.015% Nb,
The molten steel of the N of 0.021%-0.030%, no more than 0.030% P and no more than 0.020% S
Continuous casting is carried out, control continuous casting steel machine liquid temp is in the range of 1535-1565 DEG C.
Strand cast molding and when being cooled in the range of 500-700 DEG C on continuous casting casting machine, is put into slow
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.Go out behind hole and check casting ingot cross section quality, do 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,
For example when more than 800 DEG C, strand or austenite structure, without ferromagnetism, are 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 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, speed is cooled down faster
Degree also results in casting billet surface and a large amount of crackles of internal generation, therefore, it is stipulated that it 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 obtain Rel >=465MPa, Rm >=640MPa, relatively
Rate of corrosion (relative to YQ450NQR1 high-strength weather resisting steels) is the height of 65%-70%
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 using aforesaid " converter smelting and deoxygenation
Aurification → LF stove refining → continuous castings → heating strand → shape rolling mill rolling " technique productions steel of the present invention
Chemical constituent, wherein, converter smelting and deoxidation alloying → LF stove refining → continuous castings → strand
The main control parameters of heating → shape rolling mill rolling are shown in Table 2;
Compared steel 1 in table 1 is using aforesaid " converter smelting and deoxidation alloying → LF stoves essence
Refining → continuous casting → heating strand → shape rolling mill rolling " technique, the C of production, Si, 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 aforesaid " 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 is 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) method of regulation determines, and its concrete location parameter is:
Test sample is processed into the rectangle of 60mm × 40mm × 4mm, 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 is in table 1:
The heavy section steel produced using technique described in the present invention and parameter, sectional shape is shown in Fig. 5,
And at the 1/2 of the c positions (short-leg) of Fig. 5, 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
Fig. 1 can be seen that crackle+hole pattern that 30mm occurs in the centre of compared steel 1.
Wherein, using the sectional drawing after rolling of sectional iron a time after Fig. 2 is heated for the continuous casting billet of compared steel 1,
By Fig. 2 it can be found that extension occurs in crackle, whole strand is caused to be scrapped;
Wherein, Fig. 3 for compared steel 2 continuous casting billet sectional drawing (after acid etching), due to Cr contents it is 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 of the present invention 2, observes the pattern of Fig. 4,
It was found that Cross Section of CC Billet center (after acid etching) does not find centre burst and hole.
Acid etching in the present invention:Perform by GB266-91:Specifically, coarse micro-grain sample processing thickness is 18
Mm, surface is ground with grinding machine, then the low power sample for grinding 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, 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, there is not crackle and hole phenomenon in strand non-stop layer defect of the invention,
And the atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability of the present invention is improved, the intensity such as Rel and Rm of steel
There is larger improvement.As can be seen here, the present invention is provided 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, but, the present invention is not limited to above-mentioned reality
The detail in mode is applied, in the range of the technology design of the present invention, can be to the technical side of the present invention
Case carries out various 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 specific embodiment is special
Levy, in the case of reconcilable, can be combined by any suitable means, in order to avoid need not
The repetition wanted, the present invention is no longer separately illustrated to various possible combinations.
Additionally, can also be combined between a variety of embodiments of the present invention, 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)
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:The Mn of the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%,
The Cr of the Ni of the Cu of 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.16%-0.20%
V, the Ti of 0.005%-0.030%, the Nb of 0.01%-0.015%, 0.021%-0.030%'s
N, no more than 0.030% P and no more than 0.020% S.
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
The 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 slow cooling is carried out after the square billet obtained after continuous casting is cooled into 500-700 DEG C obtain to room temperature
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 the 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 refining:Step (1) gained molten steel 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 2.0%-3.5%, and Cu contents are 0.30%-0.40%, and Ni contents are
0.20%-0.30%, V content is 0.16%-0.20%, and Ti contents are 0.005%-0.030%, Nb
Content is 0.01%-0.015%, and N content is 0.021%-0.030%, P≤0.03% and S≤0.02%;
(3) continuous casting:Step (2) gained molten steel is carried out into continuous casting and obtains strand;
(4) roll:Rail will be rolled into after step (3) gained heating strand.
6. method according to claim 5, wherein,
In step (1), the outbound molten steel temperature for controlling converter smelting and deoxidation alloying is
1550-1580℃;
In step (2), the outbound molten steel temperature of LF stoves is controlled for 1570-1600 DEG C.
7. method according to claim 5, wherein,
In step (1), in controlling the outbound molten steel of 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), in the outbound molten steel of control LF stoves, on the basis of the gross weight of molten steel, Als contains
Measure as 0.01%-0.03%.
8. method according to claim 5, wherein,
In step (3), Continuous Cast Molten Steel Temperature is 1535-1565 DEG C, by the square billet obtained after continuous casting cooling
Slow cooling to room temperature is carried out to after 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. method according to claim 5, wherein, in step (2), the refining of LF stoves includes:
I) optionally, the slag on step (1) gained molten steel surface is reduced with aluminum shot, aluminum shot
Consumption is 0-1.5kg/ ton steel;
Ii) with carbon line, ferrosilicon, ferromanganese and ferrochrome to C, Si, the Mn in step (1) gained molten steel
It is adjusted with the content of Cr compositions so that meeting outbound molten steel requirement;
Iii) optionally, adjust Als contents to cause to meet outbound molten steel requirement;
Iiii) titanium, vanadium, nitrogen and niobium alloy are carried out so that Ti contents, Nb contents, N content and V
Content meets outbound molten steel requirement.
10. the atmosphere corrosion resistance structural steel that the method production in claim 5-9 described in any one is obtained,
On the basis of the gross weight of atmosphere corrosion resistance structural steel, contain:The C of 0.01%-0.09%, 0.15%-0.35%
Si, the Mn of 0.30%-0.60%, the Cu of 0.30%-0.40%, the Ni of 0.20%-0.30%,
The Ti of the V of the Cr of 2.0%-3.5%, 0.16%-0.20%, 0.005%-0.030%, 0.01%
The N of -0.015% Nb, 0.021%-0.030%, no more than 0.030% P and be not more than
0.020% S, wherein, the Rel >=465MPa of atmosphere corrosion resistance structural steel, Rm >=640MPa.
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