CN106676417B - The atmosphere corrosion resistance structural steel molten steel of nitrogen containing vanadium and atmosphere corrosion resistance structural steel and its production method - Google Patents

The atmosphere corrosion resistance structural steel molten steel of nitrogen containing vanadium and atmosphere corrosion resistance structural steel and its production method Download PDF

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CN106676417B
CN106676417B CN201510750903.6A CN201510750903A CN106676417B CN 106676417 B CN106676417 B CN 106676417B CN 201510750903 A CN201510750903 A CN 201510750903A CN 106676417 B CN106676417 B CN 106676417B
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steel
molten steel
content
corrosion resistance
slab
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CN106676417A (en
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刘明
邓通武
郭跃华
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Pangang Group Panzhihua Iron and Steel Research Institute Co Ltd
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Abstract

The present invention relates to field of steel-making, a kind of atmosphere corrosion resistance structural steel molten steel are specifically provided, on the basis of the total 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 Ni of 0.20%-0.30%, the Ti of the V of the Cr of 2.0%-3.5%, 0.13%-0.15%, 0.005%-0.030%, the N of 0.004%-0.008%, the P no more than 0.030% and the S no more than 0.020%.The present invention provides a kind of atmosphere corrosion resistance structural steel and its production methods.The center mass that slab can be improved using molten steel continuous casting of the invention, avoids the occurrence of centre burst and central pipe, and the quality of high-intensitive high atmosphere corrosion resistance structural steel slab thus can be improved, and slab qualification rate can increase substantially;And finally obtained atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability is good and has higher strength character.

Description

The atmosphere corrosion resistance structural steel molten steel of nitrogen containing vanadium and atmosphere corrosion resistance structural steel and its production method
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 molten steel of the invention The production method of atmosphere corrosion resistance structural steel and a kind of atmosphere corrosion resistance structural steel and the atmospheric corrosion resistance type obtained by this method Steel.
Background technique
Weather resisting steel is a kind of highly important steel, and weather-resistance is 2-8 times of ordinary steel, is applied Dress property improves 1.5-10 times.Validity due to weather resisting steel relative to the weather-resistant of ordinary steel, relative to stainless Steel has good economy again, so being rapidly developed in countries in the world, the various outdoor steel constructions used, railway carriage And bridge be its application range.
The weather resisting steel kind of China's early stage mainly has the 09CuPCrNi and Cor similar to Cor Ten A The simplification version 09Cu of Ten A, the yield strength of two kinds under hot-rolled condition are generally 300-450MPa.
After 2000, to improve the yield strength of steel and the low temperature impact properties of steel, pass through on the basis of 09CuPCrNi Phosphorus is reduced, and improves manganese content, has developed the steel Q450NQR1 (namely 09MnCuCrNi) of plate class, Q450NQR1 is in plate Controlled rolling and controlled cooling is used when rolling, so that it may obtain the weather resisting steel that yield strength is not less than 450MPa.And it is directed to profile not The productive prospecting of energy controlled rolling and controlled cooling by reducing 09CuPCrNi phosphorus content and improving manganese content, and adds vanadium and carries out microalloy Change, have developed the steel YQ450NQR1 (namely 09MnCuCrNiV) of profile class, is not bent by controlled rolling and controlled cooling in type steel production line 450MPa or more can also be reached by taking intensity.
After 2010, for the atmospheric corrosion resistance ability for preferably improving steel, plate types of steel is by further increasing in steel Chromium content, has 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 had large-scale production ability at present.But as the steel of profile class, improve the square continuous casting produced after chromium content Base, there are obvious central defect (predominantly centre bursts and central pipe), and the intensity index of final fashioned iron The effect of plate class steel is not achieved, therefore, the profile class steel for having more preferable atmospheric corrosion resistance ability is also constantly in research and development.
Summary of the invention
Technical problem to be solved by the invention is to provide one kind can improve high-intensitive high atmosphere corrosion resistance structural steel slab Center mass and can be improved 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 foregoing purpose, according to the first aspect of the invention, the present invention provides a kind of atmosphere corrosion resistance structural steel steel Water, on the basis of the total weight of molten steel, molten steel contains: the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%- The Cr of the Ni of the Cu of 0.60% Mn, 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.13%-0.15% V, the N of the Ti of 0.005%-0.030%, 0.004%-0.008%, P no more than 0.030% and no more than 0.020% S。
According to the second aspect of the invention, the present invention provides a kind of atmosphere corrosion resistance structural steel, the atmospheric corrosion resistance types Steel carries out continuous casting, rolling by molten steel of the present invention.
According to the third aspect of the invention we, the present invention provides a kind of production method of atmosphere corrosion resistance structural steel, this method Include:
(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 for controlling 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 content is that 0.30%-0.40%, Ni content are 0.20%-0.30%, P≤0.03% and S≤0.02%;
(2) LF furnace refines: molten steel obtained by step (1) is refined in LF furnace;
Wherein, jointly controlled by step (1) and step (2), so that each Ingredients Weight content of the outbound molten steel of LF furnace meets: C content is 0.01%-0.09%, and Si content is 0.15%-0.35%, and Mn content is 0.30%-0.60%, and Cr content is 2.0%-3.5%, Cu content be 0.30%-0.40%, Ni content be 0.20%-0.30%, V content 0.13%-0.15%, Ti content is 0.005%-0.030%, 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 slab;
(4) it rolls: rail will be rolled into after the heating of slab obtained by step (3).
According to the fourth aspect of the invention, the present invention provides the atmospheric corrosion resistances that the method according to the invention produces Fashioned iron is contained on the basis of the total weight of atmosphere corrosion resistance structural steel: the Si of the C of 0.01%-0.09%, 0.15%-0.35%, The Cr of the Ni of the Cu of the Mn of 0.30%-0.60%, 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.13%- The N of the Ti of 0.15% V, 0.005%-0.030%, 0.004%-0.008%, P no more than 0.030% and it is not more than 0.020% S, wherein atmosphere corrosion resistance structural steel Rel >=430MPa, Rm >=610MPa.
The center mass that slab can be improved using molten steel continuous casting of the invention avoids the occurrence of centre burst and center contracting Hole, thus can be improved the quality of high-intensitive high atmosphere corrosion resistance structural steel slab, and slab qualification rate can increase substantially;And it is final Obtained atmosphere corrosion resistance structural steel atmospheric corrosion resistance ability is good and has higher strength character.
The present inventor speculates, is that vanadium, titanium and nitrogen is added in high-intensitive high weather resisting steel due to the present invention, A large amount of V (C, N), Ti (C, N) particle can be formed, these particles can refine the crystal grain of slab, the development of slab dendrite is prevented, from And avoid slab center cracked and hole.In addition, these V (C, N), Ti (C, N) particle are big in subsequent slab heating Austenite can mostly be dissolved in, particle is precipitated again in rolling of sectional iron and cooling procedure after rolling, generates precipitation strength effect, improves steel Intensity.So that the present invention can not only improve slab center mass, and it can be improved the intensity of atmosphere corrosion resistance structural steel Performance and corrosion resistance.
Other features and advantages of the present invention will the following detailed description will be given in the detailed implementation section.
Detailed description of the invention
The drawings are intended to provide a further understanding of the invention, and constitutes part of specification, 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 cross-section diagram (non-acid etching) of the continuous casting billet of compared steel 1;
Fig. 2 is after the continuous casting billet of compared steel 1 heats using the cross-section diagram after rolling of sectional iron a time;
Fig. 3 is the cross-section diagram 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.
Specific embodiment
Detailed description of the preferred embodiments below.It should be understood that described herein specific Embodiment is merely to illustrate and explain the present invention, and is not intended to restrict the invention.
As previously mentioned, the present invention provides a kind of atmosphere corrosion resistance structural steel molten steel, and on the basis of the total weight of molten steel, molten steel Contain: the Cu of the Mn of the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%, 0.30%-0.40%, The Ti of the V of the Cr of the Ni of 0.20%-0.30%, 2.0%-3.5%, 0.13%-0.15%, 0.005%-0.030%, The N of 0.004%-0.008%, the P no more than 0.030% and the S no more than 0.020%.Using the molten steel continuous casting of aforementioned component Obtained slab (alternatively referred to as continuous casting billet) center mass is improved, and Cross Section of CC Billet center (after acid etching) basic non-stop layer is split Line and hole.
Molten steel according to the present invention, other than 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 Analysis and practice discovery obtain.
Specifically, the present inventor is by theory analysis and practice discovery:
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 Substantial increase, but the toughness of steel and weldability decline therewith, and fashioned iron is usually required that with good weldability and toughness, institute With the present invention claims C controls within the scope of 0.01%-0.09%, Si is controlled within the scope of 0.15%-0.35%, and Mn control exists Within the scope of 0.30%-0.60%.
P is one of the element for improving steel atmospheric corrosion resistance ability, and the P content of Cu-P system weather resisting steel is reachable 0.07%-0.12%.But P is again the element for improving black brittleness transition temperature, 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 lower better, therefore is limited to 0.020% or less.
Cu, Cr and Ni in steel can not only make steel have good atmospheric corrosion resistance ability, but also can improve the intensity of steel.But Since Cu and Ni alloy price is much higher than Cr alloy, from the economy of steel, the present invention controls Cu in 0.30%-0.40%, Cr is in 2.0%-3.5%, and Ni is within the scope of 0.20%-0.30%.But since Cr content is very high, lead to the poor fluidity of molten steel, In conjunction with other alloys producings, slab is easy to appear underbead crack, which must take other technical measures to give to overcome.
To overcome Cr content to improve bring defect, the present invention increases V, Ti, N element in molten steel and solves this hair Bright technical problem speculates that these elements can improve slab center mass below for the present inventor, and improves steel The possible cause of intensity:
In the cooling procedure of slab, Ti (C, N) particle can be precipitated in slab containing Ti, prevent the development of slab dendrite, drop A possibility that low formation coarse dendrite, while the degree that slab selects part to crystallize also reduces, so as to improve slab internal structure, Avoid the formation of centre burst and hole.In addition, can also have been found in the heating process of subsequent steel billet at 1250 DEG C or more It is not dissolved in Ti (C, N) particle of austenite, growing up for austenite grain can be prevented.Therefore, be added a certain amount of Ti be it is useful, But the excessive titanium square frame-shaped easy to form for being greater than 30 μm is mingled with, and scratches steel matrix, so the Ti element of addition is not easy excessively, control System is in 0.005%-0.03% than advantageous.
V can also form V (C, N) particle, and the development of slab dendrite can be also prevented in the cooling procedure of slab, reduce shape A possibility that at coarse dendrite, while the degree that slab selects part to crystallize also reduces, and so as to improve slab internal structure, avoids The formation of centre burst and hole.In addition, V (C, N) particle starts to be dissolved in austenite at 600 DEG C or so in 2 Mo Steel Slab during Heating Process In, 900 DEG C -1000 DEG C are completely dissolved in austenite, are precipitated from austenite in subsequent rolling and roller repairing, precipitation strength Effect is obvious.To guarantee to obtain a certain amount of V (C, N) particle, the V that 0.13%-0.15% is added is necessary.
N content is insufficient, and the quantity for forming TiC and VC is on the high side, and the quantity of TiN and VN are on the low side, is that unfavorable Ti and V performance is beneficial Effect, therefore the present invention need to control N within the scope of 0.004%-0.008%.N can be brought into steel with furnace charge and alloy, liquid Metal can also from atmosphere suction part N, the residual N content of usual basic oxygen converter 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 basic oxygen converter smelting steel, Part N need to be supplemented using the alloy containing N.
Molten steel according to the present invention, preferably on the basis of the total weight of molten steel, the Als content in molten steel is 0.01%- 0.03%.
Molten steel according to the present invention, the preferably temperature of molten steel are 1535-1565 DEG C, using the steel of aforementioned component of the invention Water and the temperature for controlling molten steel are 1535-1565 DEG C, can directly carry out continuous casting, the center mass for the slab that continuous casting obtains can Further improved, and can finally further increase hardness of steel index and corrosion resistance.
As previously mentioned, the atmosphere corrosion resistance structural steel is by institute of the present invention the present invention provides a kind of atmosphere corrosion resistance structural steel The molten steel stated carries out continuous casting, rolling.
The temperature (or being Continuous Cast Molten Steel Temperature) of atmosphere corrosion resistance structural steel according to the present invention, the preferably described continuous casting is 1535-1565 DEG C, when the temperature of the molten steel in the range when, without further progress temperature adjust, can directly carry out Continuous casting.
Atmosphere corrosion resistance structural steel according to the present invention, 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 slab and is then rolled, wherein preferred slow cooling rate is 5-100 DEG C/h, more preferably 10-30 ℃/h。
The present invention to the mode of slow cooling without particular/special requirement, as long as meeting aforementioned slow cooling rate can be realized mesh of the invention 's.Such as square billet heap can be entered to burial pit and carry out slow cooling.
Then burial pit can for example be covered by adding melt pit to reduce cooling rate and realize the slow cooling.
It was found by the inventors of the present invention that burial pit, such as 800 DEG C or more are added in excessive temperature in slow cooling temperature control When, slab or austenite structure are unfavorable for the safety operation of ferromagnetic class crane without ferromagnetism, 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 range at 400 DEG C or so Even if the cooling velocity of the slab steel containing chromium does not reach the temperature Rate that martensitic traoformation occurs, faster cooling velocity also can Lead to 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.
Atmosphere corrosion resistance structural steel according to the present invention, the finishing temperature preferably rolled are 700-950 DEG C.
Using with aforementioned component molten steel carry out continuous casting, rolling can be obtained meet the present invention claims atmospheric corrosion resistance Fashioned iron, 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 increase Slab center mass improves slab central defect, and improves the strength character and corrosion resistance of steel, and preferably of the invention is resistance to big The production method of gas corrosion fashioned iron 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 for controlling 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 content is that 0.30%-0.40%, Ni content are 0.20%-0.30%, P≤0.03% and S≤0.02%;
(2) LF furnace refines: molten steel obtained by step (1) is refined in LF furnace;
Wherein, jointly controlled by step (1) and step (2), so that each Ingredients Weight content of the outbound molten steel of LF furnace meets: C content is 0.01%-0.09%, and Si content is 0.15%-0.35%, and Mn content is 0.30%-0.60%, and Cr content is 2.0%-3.5%, Cu content be 0.30%-0.40%, Ni content be 0.20%-0.30%, V content 0.13%-0.15%, Ti content is 0.005%-0.030%, 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 slab;
(4) it rolls: rail will be rolled into after the heating of slab obtained by step (3).
The present inventor is by long-term theory analysis and practice discovery, because the affinity of Cu and Ni and O is small, very not It is oxidized easily, when converter smelting process is added, recovery rate just can reach 100%, therefore arrive in the control of one step of converter procedure Position controls Cu and Ni respectively within the scope of 0.30%-0.40% and 0.20%-0.30%, subsequent to be no longer adjusted.
With the method for the invention it is preferred to control the outbound molten steel temperature of converter smelting and deoxidation alloying in step (1) It is 1550-1580 DEG C.
With the method for the invention it is preferred in step (1), in the outbound molten steel of control converter smelting and deoxidation alloying, On the basis of the total weight of molten steel, Als content is 0.02%-0.05%.
In the present invention, preferably converter uses Al deoxidization technique, and controls Als (dissolved aluminum) in 0.02%-0.05% range Interior, control converter tapping liquid temperature is 1550-1580 DEG C.Control Als allows for rear portion in 0.02-0.05% range herein There are Als to be oxidized to Al for LF furnace refining procedure and continuous casting steel machine2O3The phenomenon that, the scaling loss amount of the Als of the two-step is general Within the scope of 0.010%-0.02%, by a large amount of it was verified that the Als of slab after cooling can be after last continuous casting steel machine Within the scope of 0.01-0.03%.
With the method for the invention it is preferred to which the control outbound molten steel temperature of LF furnace is 1570-1600 DEG C in step (2).
With the method for the invention it is preferred to control in the outbound molten steel of LF furnace, in step (2) using the total weight of molten steel as base Standard, Als content are 0.01%-0.03%.
With the method for the invention it is preferred to which Continuous Cast Molten Steel Temperature is 1535-1565 DEG C in step (3).
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 slab.
With the method for the invention it is preferred to slow cooling rate be 5-100 DEG C/h, more preferably 10-30 DEG C/h.
With the method for the invention it is preferred to which temperature after heating is 1100-1250 DEG C in step (4).
With the method for the invention it is preferred to which finishing temperature is 700-950 DEG C in step (4).
In the present invention, converter smelting and deoxidation alloying, the refining of LF furnace, continuous casting and rolling can according to conventional steps into Row, as long as its technological parameter can satisfy preferred requirement of the invention and can preferably achieve the object of the present invention.
In the present invention, after rolling, the method that natural air cooling can be used is cooled down.
According to the method for the present invention, the LF furnace refining can be carried out according to conventional steps, for the present invention, preferred steps (2) in, the refining of LF furnace includes:
I) optionally, restored with steel slag of the aluminum shot to molten steel surface obtained by step (1), the dosage of aluminum shot is 0- 1.5kg/ tons of steel;
Ii) with carbon line, ferrosilicon, manganese iron and ferrochrome to the content of C, Si, Mn and Cr ingredient in molten steel obtained by step (1) into Row adjustment is so that meet outbound molten steel requirement;
Iii) optionally, adjustment Als content to meet outbound molten steel requirement;
Iiii titanium, vanadium, nitrogen alloying) are carried out and makes Ti content, N content and V content meet outbound molten steel requirement.
As previously mentioned, the present invention provides the atmosphere corrosion resistance structural steels that the method according to the invention produces.
Atmosphere corrosion resistance structural steel according to the present invention contains preferably on the basis of the total weight of atmosphere corrosion resistance structural steel: The Cu of the Mn of the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%, 0.30%-0.40%, The Ti of the V of the Cr of the Ni of 0.20%-0.30%, 2.0%-3.5%, 0.13%-0.15%, 0.005%-0.030%, The N of 0.004%-0.008%, the P no more than 0.030% and the S no more than 0.020%.
Atmosphere corrosion resistance structural steel according to the present invention, other than mentioned component, remaining is inevitable impurity and Fe.
Atmosphere corrosion resistance structural steel according to the present invention, preferably Rel >=430MPa of atmosphere corrosion resistance structural steel, preferably 430- 460MPa。
Atmosphere corrosion resistance structural steel according to the present invention, preferably Rm >=610MPa of atmosphere corrosion resistance structural steel, preferably 610- 640MPa。
The tool for producing atmosphere corrosion resistance structural steel of the invention according to a preferred embodiment of the present invention is described below Body implementation steps produce atmosphere corrosion resistance structural steel 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 furnace refining → continuous casting → slab heating → shape rolling mill Rolling.
The concrete operations content of every process is as follows:
A converter smelting and deoxidation alloying
When using converter smelting molten steel, the chemical constituent of C, Si, Mn and Cr control target in molten steel are as follows: C 0.01%- 0.09%, Si 0.15%-0.35%, Mn 0.30%-0.60% and Cr2.0%-3.5%.This process is only to control target, should For process if do not can control in target zone, subsequent LF furnace refining procedure is also adjustable.
Control P≤0.030%, S≤0.020% in molten steel.
Because the affinity of Cu and Ni and O is small, it is not easy to be oxidized very much, when converter smelting process is added, recovery rate can Reach 100%, therefore controlled in place in one step of converter procedure, is i.e. control Cu and Ni is respectively in 0.30%-0.40% and 0.20%- It is subsequent to be no longer adjusted in 0.30% range.
Converter uses Al deoxidization technique, and controls Als (dissolved aluminum) within the scope of 0.02%-0.05%, and control converter goes out Molten steel temperature is 1550-1580 DEG C.Control Als is in 0.02-0.05% range herein, allow for rear portion LF furnace refining procedure and There are Als to be oxidized to Al for continuous casting steel machine2O3The phenomenon that, the scaling loss amount of the Als of the two-step is generally in 0.010%- In 0.02% range, by a large amount of it was verified that the Als of slab after cooling can be in 0.01- after last continuous casting steel machine In 0.03% range.
The refining of B LF furnace
Molten steel optionally includes and the step of aluminum shot restores steel slag is added, aluminum shot additional amount is when LF furnace refines 0-1.5kg/ tons of steel;
After LF furnace electric heating, micro adjustment is carried out to C, Si, Mn and Cr ingredient with carbon line, ferrosilicon, manganese iron and ferrochrome, is adjusted Range 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 C, Si, Mn and Cr fine tuning, Als in sampling analysis molten steel, adjustment Als content is 0.01%-0.03%;Such as Als is lower than 0.02%, then needs that Als is adjusted to 0.025% or so using the method that aluminum shot is added or feeds aluminum steel, can protect The Als of slab is controlled within the scope of 0.01%-0.03% after card continuous casting cast steel.Control Als is to examine 0.025% or so herein Considering rear portion continuous casting steel machine process, there are Als to be oxidized to Al2O3The phenomenon that, by a large amount of it was verified that continuous casting steel machine process The oxidation of slab Als is within the scope of 0.005-0.015%.
After adjusting Als, ferrotianium and VN alloy (VN12, VN14 and VN16) is added, controls the Ti in molten steel Within the scope of 0.005%-0.030%, V is controlled within the scope of 0.13%-0.15%, and N is controlled in 0.004%-0.008% range Interior, the control outbound molten steel temperature of LF furnace is 1570-1600 DEG C.
C continuous casting
Chemical component (weight percent) is Si, 0.30%- of C, 0.15%-0.35% of 0.01%-0.09% Cr, 0.13%-0.15% of Ni, 2.0%-3.5% of Cu, 0.20%-0.30% of 0.60% Mn, 0.30%-0.40% V, 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% Molten steel carry out continuous casting, control continuous casting steel machine liquid temperature within the scope of 1535-1565 DEG C.
Slab is put into burial pit and is delayed in cast molding on continuous casting casting machine and when being cooled within the scope of 500-700 DEG C It is cold, after slow cooling to room temperature go out burial pit, slow cooling rate be 5-100 DEG C/h, preferably 10-30 DEG C/h.Check that slab is disconnected after cheating out Face quality, does not find centre burst and hole.
It was found by the inventors of the present invention that burial pit, such as 800 DEG C or more are added in excessive temperature in slow cooling temperature control When, slab or austenite structure are unfavorable for the safety operation of ferromagnetic class crane without ferromagnetism, 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 range at 400 DEG C or so Even if the cooling velocity of the slab steel containing chromium does not reach the temperature Rate that martensitic traoformation occurs, faster cooling velocity also can Lead to 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.
The heating of D slab and rolling
After high-intensitive high atmosphere corrosion resistance structural steel slab is heated to 1100 DEG C -1250 DEG C, then carry out slab rolling to fashioned iron System, within the scope of 700 DEG C -950 DEG C, the fashioned iron being finally rolled into can be obtained finishing temperature control by the way of natural air cooling To Rel >=430MPa, Rm >=610MPa, relatively corrosive rate (relative to YQ450NQR1 high-strength weather resisting steel) 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 produced under same process conditions and compared steel, intensity index, and The comparative situation of slab central defect.
Steel of the present invention 1,2,3 and 4 in table 1 be using it is above-mentioned " converter smelting and deoxidation alloying → LF furnace refining → Continuous casting → slab heating → shape rolling mill rolling " technique produces the chemical constituent of steel of the present invention, wherein converter smelting and deoxygenation Aurification → LF furnace refining → continuous casting → slab heating → shape rolling mill rolling main control parameters are shown in Table 2;
Compared steel 1 in table 1 is using " converter smelting and deoxidation alloying → LF furnace refining → continuous casting → slab above-mentioned Heating → shape rolling mill rolling " technique, C, Si, Mn, Cr, Ni and Cu chemical component of production and base steel sheet of the present invention are identical right Compare steel;
Compared steel 2 in table 1 is using " converter smelting and deoxidation alloying → LF furnace refining → continuous casting → slab above-mentioned Heating → shape rolling mill rolling " technique, the chemical component of the existing YQ450NQR1 high strength atmospheric corrorsion resistant section steel of production;
The measuring 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 measurement, specific location parameter are as follows: test sample is processed into 60mm × 40mm × 4mm square Shape, it is desirable that the surface roughness of largest face is 3.2 μm;Temperature is 45 ± 2 DEG C;Humidity are as follows: 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 are as follows: (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 steel is opposite Rate of corrosion is 100%.
The sampling point and sampling state of intensity index and relatively corrosive rate measurement sample in table 1 are as follows: 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 the position c (short-leg) of Fig. 5, and Prolong rolling direction and takes tension test and corrosion coupon sample.
Wherein, Fig. 1 is the cross-section diagram (non-acid etching) of the continuous casting billet (also referred to as slab) of compared steel 1, as seen from Figure 1, There is crackle+hole pattern of 30mm in the centre of compared steel 1.
Wherein, Fig. 2 be compared steel 1 continuous casting billet heating after using the cross-section diagram after rolling of sectional iron a time, can be with by Fig. 2 It was found that crackle extends, entire slab is caused to be scrapped;
Wherein, Fig. 3 is the cross-section diagram (after acid etching) of the continuous casting billet of compared steel 2, since Cr content is low, and other alloying elements Total amount is also below the alloy total amount of chemical component 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 the pattern of Fig. 4, and discovery continuous casting billet is disconnected Face center (after acid etching) does not find centre burst and hole.
Acid etching in the present invention: it is executed by GB266-91: specifically, coarse micro-grain sample processing is with a thickness of 18mm, surface grinding machine It grinds, then the low power sample ground is put into 70 DEG C of technical hydrochloric acid aqueous solutions (technical hydrochloric acid: water=1:1), etching time It is 15 minutes, is then taken out from aqueous hydrochloric acid solution, observes surface topography after cooling.
Wherein, Fig. 5 is the cross-sectional view of heavy section steel, and a (indicating the intermediate position of heavy section steel, be commonly called as waist) is 310mm, b (indicating an end of heavy section steel, be commonly called as long leg) are 174mm, and c (indicates another end of heavy section steel, custom Short-leg) it is referred to as 125mm, d (indicating an end of heavy section steel, be commonly called as the thickness of long leg) is 12mm, and e (indicates heavy section steel Intermediate position, be commonly called as the thickness of waist) be 12mm, f (indicate heavy section steel another end, be commonly called as the thickness of short-leg) be 18mm。
Table 1
As shown in Table 1, slab 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 of steel such as Rel and Rm have larger improvement.It can be seen that 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 has been described above in detail, still, during present invention is not limited to the embodiments described above Detail within the scope of the technical concept of the present invention can be with various simple variants of the technical solution of the present invention are made, this A little simple variants all belong to the scope of protection of the present invention.
It is further to note that specific technical features described in the above specific embodiments, in not lance In the case where shield, can be combined in any appropriate way, in order to avoid unnecessary repetition, the present invention to it is various can No further explanation will be given for the combination of energy.
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 also be regarded as the disclosure of the present invention.

Claims (10)

1. a kind of atmosphere corrosion resistance structural steel, which is characterized in that the atmosphere corrosion resistance structural steel carries out continuous casting by molten steel, rolls It arrives;On the basis of the total weight of molten steel, molten steel is made of following weight percent chemical component: the C of 0.01%-0.09%, The Ni of the Cu of the Mn of the Si of 0.15%-0.35%, 0.30%-0.60%, 0.30%-0.40%, 0.20%-0.30%, are greater than 2.0% and be not more than 3.5% Cr, the Ti of the V of 0.13%-0.15%, 0.005%-0.030%, 0.004%-0.008%'s N, the P no more than 0.030% and the S no more than 0.020%, remaining is inevitable impurity and Fe;The temperature of the continuous casting It is 1535-1565 DEG C, and carries out slow cooling to room temperature after the square billet obtained after continuous casting is cooled to 500-700 DEG C and obtain slab then It is rolled, wherein slow cooling rate is 5-100 DEG C/h;The finishing temperature of rolling is 700-950 DEG C.
2. atmosphere corrosion resistance structural steel according to claim 1, wherein the temperature of molten steel is 1535-1565 DEG C, with molten steel On the basis of total weight, the Als content in molten steel is 0.01%-0.03%.
3. atmosphere corrosion resistance structural steel according to claim 1, wherein slow cooling rate is 10-30 DEG C/h.
4. a kind of production method of atmosphere corrosion resistance structural steel, which is characterized in that this method comprises:
(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 total weight of molten steel On the basis of, Cu content is that 0.30%-0.40%, Ni content are 0.20%-0.30%, P≤0.03% and S≤0.02%;
(2) LF furnace refines: molten steel obtained by step (1) is refined in LF furnace;
Wherein, jointly controlled by step (1) and step (2), so that each Ingredients Weight content of the outbound molten steel of LF furnace meets: C contains Amount is 0.01%-0.09%, and Si content is 0.15%-0.35%, and Mn content is 0.30%-0.60%, and Cr content is 2.0%- 3.5%, Cu content are 0.30%-0.40%, and Ni content is 0.20%-0.30%, V content 0.13%-0.15%, Ti content For 0.005%-0.030%, 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 slab;
(4) it rolls: rail will be rolled into after the heating of slab obtained by step (3).
5. according to the method described in claim 4, wherein,
In step (1), the outbound molten steel temperature for controlling converter smelting and deoxidation alloying is 1550-1580 DEG C;
In step (2), the control outbound molten steel temperature of LF furnace is 1570-1600 DEG C.
6. according to the method described in claim 4, wherein,
In step (1), in the outbound molten steel of control converter smelting and deoxidation alloying, on the basis of the total weight of molten steel, Als contains Amount is 0.02%-0.05%;
It in step (2), controls in the outbound molten steel of LF furnace, on the basis of the total weight of molten steel, Als content is 0.01%-0.03%.
7. according to the method described in claim 4, 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 slab, wherein slow cooling rate is 5-100 DEG C/h;
In step (4), temperature after heating is 1100-1250 DEG C, and finishing temperature is 700-950 DEG C.
8. according to the method described in claim 7, wherein, the slow cooling rate is 10-30 DEG C/h.
9. according to the method described in claim 4, wherein, in step (2), the refining of LF furnace includes:
I) optionally, restored with steel slag of the aluminum shot to molten steel surface obtained by step (1), the dosage of aluminum shot is 0-1.5kg/ tons Steel;
Ii it) is adjusted with the content of carbon line, ferrosilicon, manganese iron and ferrochrome to C, Si, Mn and Cr ingredient in molten steel obtained by step (1) It is whole so that meeting outbound molten steel requirement;
Iii) optionally, adjustment Als content to meet outbound molten steel requirement;
Iiii titanium, vanadium, nitrogen alloying) are carried out and makes Ti content, N content and V content meet outbound molten steel requirement.
10. the atmosphere corrosion resistance structural steel that method described in any one of claim 4-9 produces, with atmospheric corrosion resistance type On the basis of the total weight of steel, contain: the Mn of the Si of the C of 0.01%-0.09%, 0.15%-0.35%, 0.30%-0.60%, The V of the Cr of the Ni of the Cu of 0.30%-0.40%, 0.20%-0.30%, 2.0%-3.5%, 0.13%-0.15%, 0.005%- The N of 0.030% Ti, 0.004%-0.008%, the P no more than 0.030% and the S no more than 0.020%, wherein resistance to atmosphere Corrode the Rel >=430MPa, Rm >=610MPa of fashioned iron.
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