CN109207851B - Ultrahigh-strength steel plate and manufacturing method thereof - Google Patents
Ultrahigh-strength steel plate and manufacturing method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
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- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
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Abstract
The ultrahigh-strength steel plate comprises the following components in percentage by weight: c: 0.24-0.26%, Si: 0.1-0.25%, Mn: 1.15-1.25%, P is less than or equal to 0.015%, S is less than or equal to 0.005%, Al: 0.015 to 0.025%, Mo: 0.25-0.45%, B: 0.001-0.005% and less than or equal to 0.004% of N; nb: 0.015 to 0.025%, Ti: 0.01-0.025%, V: 0.045-0.055%, and the balance of Fe and inevitable impurities. The invention can realize the production of 2.5-6mm thin high-strength steel plates, the yield strength of the steel plates is above 1300MPa, the tensile strength is over 1500MPa, the elongation is more than or equal to 8 percent, and the impact power value at-40 ℃ is over 27J, thereby meeting the bending requirements of D-8 a and 90 degrees, having excellent forming performance and good flatness.
Description
Technical Field
The invention relates to the field of low alloy steel manufacturing, in particular to an ultra-high strength steel plate with yield strength exceeding 1300MPa and a manufacturing method thereof, and particularly relates to a hot-rolled heat-treated high strength steel plate with the thickness specification of 2.5-6mm for engineering machinery.
Background
High-strength steel is widely applied to engineering machinery such as cranes, concrete pump trucks, dump trucks and the like, and the strength of steel plates is also developed from original plain carbon steel to low-alloy steel of 960MPa grade. Along with the increase of the tonnage of equipment, the strength of the high-strength steel is gradually increased to the level of yield strength 1100MPa, even 1300MPa, and higher requirements are provided for the unevenness, welding performance and forming performance of the steel plate.
The high-strength steel plate can be obtained by adopting a controlled cooling mode and controlled rolling and offline heat treatment. The production of the high-strength steel plate by controlling the air cooling mode is limited by the equipment capacity (such as a coiler), the yield strength of the steel plate is usually below 800MPa, the specification is limited, and the problems of uneven performance and structure and poor plate shape exist at the same time, so that the normal use of a user is influenced; the steel plate with higher strength grade can be produced by adopting the controlled rolling and offline heat treatment process, particularly, the hardenability of the steel is improved by adding alloy elements, and a martensite structure with higher strength and hardness can be obtained. The simple martensite structure has a defect of high density between martensite lamellar layers, and is liable to become a crack source, thereby deteriorating impact toughness of the material. Therefore, it is necessary to adopt a specific component system and a production process to obtain a high-strength steel plate with higher strength, good plasticity and toughness.
In recent years, high-strength steels in the field of engineering machinery have been disclosed domestically, such as "weldable ultrahigh-strength steel excellent in ultralow temperature toughness" in chinese patent publication No. CN1265709A and "super-strength steel sheet having yield strength of 1100MPa or more" in chinese patent publication No. CN1840723A and a method for manufacturing the same ", but it relates to a steel sheet having yield strength which is relatively low, even below 1000 MPa; chinese patent publication No. CN104498834A 'a component and a preparation process of a high-toughness ultrahigh-strength steel' and Chinese patent publication No. CN107338393A 'an ultrahigh-strength steel plate with yield strength more than 1400MPa and a production method thereof', although the steel involved has high strength, the steel needs to be added with high alloy content, such as C, Si, Mn, Cr, Mo, W, Ni and the like, on one hand, the cost is high, and meanwhile, the high alloy reduces the weldability and limits the application thereof.
Also, as in US2007095444 "a high-strength steel sheet excellent in formability and a method for producing the same" and JP2012041611 "a method for producing a high-strength steel sheet with stable properties" relate to a low strength steel sheet, and US2014162088 "a high-strength galvanized sheet with good formability and a method for producing the same" relate to a steel sheet having a strength of only about 900MPa and contain a high C, Si content.
For example, Chinese patent CN102747303A "high-strength steel sheet and manufacturing method thereof" and CN102337480A "ultrahigh-strength steel sheet with excellent environmental brittleness resistance and fatigue resistance and manufacturing method thereof". The two patents relate to that the steel plates are thick plate products, wherein the steel plates contain high content of C and Si, and contain Mo and 2.0% Ni with the upper limit of 0.9%, so the cost is high; the latter has Mn content of 2-6% and contains much Si and Cr, which is unfavorable for welding performance. Chinese patent No. CN102884218A "high-strength steel plate and its manufacturing method" relates to a high-strength steel with yield strength over 1400MPa, but it is designed for high C-Si-Mn component, at the same time, it contains Al up to 3.0%, and needs to add rare earth component, the upper limits of Cr and Ni contents reach 0.8 and 5.0% respectively, not only the cost is high, but also the forming and welding properties are poor, and it is not suitable for engineering machinery field.
On the component system, the patent steels with the yield strength exceeding 960MPa are designed by adopting higher C-Si-Mn, and simultaneously, more elements such as Cu, Cr, Ni, Mo and even Al are required to be added; higher strength patented steels require high C alloys such as up to 0.45% C and 2-4.5% Cr, Ni, W, etc. Although C has a phase change strengthening effect, excessive C inevitably causes the deterioration of welding performance, and more Si is also unfavorable for the surface, toughness and plasticity and welding performance; and the addition of more precious alloys increases the cost, and simultaneously, the welding and forming performances are inevitably deteriorated, and the using and processing difficulty is greatly improved.
Disclosure of Invention
The invention aims to provide an ultrahigh-strength steel plate and a manufacturing method thereof, which can realize the production of a thin high-strength steel plate with the thickness of 2.5-6mm, the yield strength of the steel plate is more than 1300MPa, the tensile strength is more than 1500MPa, the elongation is more than or equal to 8 percent, meanwhile, the impact power value at-40 ℃ is more than 27J, the bending requirements of D-8 a and 90 degrees are met, the forming performance is excellent, and the flatness is good.
In order to achieve the purpose, the technical scheme of the invention is as follows:
the invention adopts microalloy strengthening of Nb, V and Ti on the basis of proper C-Mn, and is assisted by a small amount of alloying elements such as Mo, B and the like, and the manufacturing method realizes high strength and high toughness and low cost by heat treatment of phase change strengthening and microalloy fine grain strengthening and precipitation strengthening.
Specifically, the ultrahigh-strength steel plate comprises the following components in percentage by weight: c: 0.24-0.26%, Si: 0.1-0.25%, Mn: 1.15-1.25%, P is less than or equal to 0.015%, S is less than or equal to 0.005%, Al: 0.015 to 0.025%, Mo: 0.25-0.45%, B: 0.001-0.005% and less than or equal to 0.004% of N; nb: 0.015 to 0.025%, Ti: 0.01-0.025%, V: 0.045-0.055%, and the balance of Fe and inevitable impurities.
In the composition design of the steel of the invention:
c is an element that does not necessarily need to be reduced in the transformation from austenite to martensite, bainite, or other strengthening phases, and can improve the hardenability of steel, so that the steel sheet forms a martensite structure having higher hardness after quenching. The content of C determines the strength grade of the steel plate to a great extent and also directly determines the carbon equivalent of the steel grade, and the carbon equivalent is a key index influencing the strength and the welding performance of the steel. A low C content does not allow sufficient strengthening phase to be formed to ensure strength, while too high a C content is detrimental to plasticity, weldability and toughness. The invention takes C as the most important strengthening element, and the range of the C is limited to 0.24-0.26% (without 0.26%) under the condition of meeting the performance requirement.
Si is a deoxidizing element, and can raise the Ac3 temperature of the steel sheet and promote the formation of ferrite. Si substitutes Fe atoms in the steel in a replacement mode, so that dislocation movement is hindered, and solid solution strengthening is realized. However, Si has a strength-improving effect smaller than that of C, and increases the work hardening rate at cold working, thereby lowering the toughness and plasticity of steel to some extent. Meanwhile, the excessively high Si promotes the graphitization of C, which is unfavorable for toughness; while being detrimental to surface quality and weldability. Therefore, the present invention limits the content range to 0.1 to 0.25%.
Mn is an element that promotes the formation of austenite. Mn solid-dissolved in austenite can inhibit diffusion type phase transformation (CCT curve is shifted to the right) in the quenching process, thereby improving hardenability and promoting the refinement of martensite structure. Meanwhile, Mn obviously reduces the phase transition temperature of the steel, refines the microstructure of the steel, is an important strengthening and toughening element, can inhibit the formation of reticular cementite and is beneficial to toughness. However, an excessive content of Mn causes segregation, deteriorates the matrix structure and forms large MnS inclusions, thereby deteriorating the weldability and the weld heat-affected zone toughness of the steel sheet. And the higher Mn reduces the Ms point, leads to increase of residual austenite, reduces the yield ratio of the steel plate and increases the temper brittleness of the steel plate. In addition, excessive Mn lowers the thermal conductivity of the steel, lowers the cooling rate, may cause coarse grains, and is disadvantageous in toughness and fatigue properties. So the control is between 1.15 and 1.25 percent.
P is a main corrosion resistant element in the traditional atmospheric corrosion resistant steel, and meanwhile, the P is easy to generate segregation at a crystal boundary, so that the crystal boundary bonding energy and the toughness and plasticity of the steel are reduced; meanwhile, the coexistence of P and Mn can aggravate the temper brittleness of the steel, and the deviated P ensures that the steel plate is easy to generate crystal fracture and reduces the impact toughness of the steel plate. And P is disadvantageous in welding performance. Therefore, in the present invention, P is treated as an impurity element to reduce the content of P in the steel as much as possible, and the content is required to be 0.015% or less in the present invention.
S is easy to form plastic inclusion manganese sulfide with Mn in the solidification process, and is unfavorable for transverse plasticity and toughness; s is easily oxidized to form SO during welding2Gas, leading to weld porosity and porosity defects. Further, S is also a main element which causes hot shortness in hot rolling, and therefore, the lower the S, the better. In the present invention, the content is controlled to be 0.005 or less.
Al is generally added as a deoxidizer in the steel making process. And a small amount of Al forms fine AlN precipitation during steelmaking, austenite grains are refined during cooling, and the toughness of the steel is improved. Therefore, it is also used as a N-fixing agent in steel. However, when AIN exists independently in steel as a non-metallic inclusion, continuity of a steel matrix is damaged, and particularly, when AIN with a high Al content is formed in a large amount and in an aggregated distribution, the AIN is more harmful and forms oxides with poor plasticity. And too high Al forms coarse alumina particles, increasing the ferrite brittleness in the steel, decreasing the toughness of the steel. Therefore, the content is controlled to be 0.015 to 0.025 percent.
B is concentrated in dislocations and defects in the steel, reduces grain boundary energy, inhibits ferrite transformation, and thus has good hardenability, thereby improving steel sheet hardness. The addition of B can replace the addition of noble alloy elements such as Mo and Ni, thereby reducing the cost. In addition, B can improve the low-temperature impact toughness of the steel plate after low-temperature tempering and reduce the ductile-brittle transition temperature. However, too high B causes a decrease in grain boundary strength, and is cleaved by intergranular fracture under stress to form "boron embrittlement", and too high B is not favorable for welding, and therefore, the respective ranges thereof are controlled to be 0.001 to 0.005%.
Nb is a strong nitrogen carbide forming element and can be combined with carbon and nitrogen in steel to form intermediate phases such as NbC, Nb (CN), NbN and the like, and formed fine carbide particles are subjected to nail-rolling of austenite grain boundaries in the austenitizing process, so that the abnormal growth of the austenite grain is inhibited, and the structure is refined. The method has the advantages that the Nb carbonitride is controlled to be separated out in austenite and low-temperature ferrite in the rolling process, and interphase precipitation occurs, so that the method has the functions of precipitation strengthening and precipitation strengthening, and the strength of the steel plate is obviously improved; meanwhile, the carbonitrides are beneficial to improving the toughness of the steel plate after quenching. Nb can also suppress the expansion of the austenite interface and increase the recrystallization temperature of the steel. If Nb is too high, coarse carbonitride particles are formed at the grain boundaries when the Nb content to be formed is high, and the impact toughness deteriorates. Meanwhile, Nb is used as a precious alloy element, and the cost is increased when the addition amount is high. Therefore, the content is controlled within the range of 0.015-0.025%.
V is an element that reduces austenite and is the only element that can be precipitated both in the austenite-ferrite transformation process and in the ferrite. Reducing the diffusion rate of C in austenite increases hardenability. The carbonitride of V can be completely dissolved in austenite when the content of N is low, and interphase precipitation and ferrite precipitation strengthening are realized in the austenite-ferrite transformation process; at high N VN is less soluble in austenite and ferrite and therefore precipitates in large amounts during rolling and prevents grain growth and increases tempering stability and thus strength. When the V content is too high, coarse carbonitride particles are likely to be formed, and the impact toughness is deteriorated. Therefore, the content is controlled to be 0.045-0.055%.
Ti is a strong ferrite forming element, the formation temperature of titanium nitride is above 1400 ℃, the titanium nitride is precipitated in high-temperature liquid phase or ferrite, and fine precipitates can be nailed and rolled in grain boundaries, so that austenite grains are refined, and the welding performance of the steel plate is improved. Ti reduces the temper brittleness of the steel at the temperature of 250-400 ℃, and the addition of Ti and B can obviously reduce the temper brittleness. Ti in Al-containing steel can preferentially bind with N in the steel, and the amount of AlN in the steel can be reduced. Therefore, the range of the components of the limiter is 0.015-0.025%.
Mo narrows the austenite region, and improves hardenability during quenching heat treatment, thereby promoting formation of martensite structure. Carbide type of Mo includes MC, M2C、M23C6And M6C, Mo exists in the steel in the form of carbide and solid solution, and further causes a solid solution strengthening effect. Mo can improve the tempering stability of the steel, slow down the tempering softening phenomenon and inhibit the high-temperature tempering brittleness. When Mo is present together with Cr and Mn, the temper brittleness caused by other elements is reduced, and the low-temperature impact toughness of the steel plate is improved. However, higher Mo is disadvantageous in welding performance and increases cost, so that the content thereof is limited to 0.25 to 0.45%.
Addition of Ca to steel can change the shape of sulfides and inhibit the hot brittleness of S. And when there is an excess of Ti in the steel, it may form titanium sulfide or titanium carbosulfide with the sulfide. The effect of low Ca content is not obvious, the size of Ca (O, S) formed by high Ca content is too large, the brittleness is also increased, the Ca can become the starting point of fracture crack, and the purity of steel is reduced. The addition of Ca is controlled to be 0.001-0.023 percent, and the Ca/S is more than or equal to 0.5-2.0.
N can form nitrides with Al and Ti in steel, and fine precipitates have the function of nail rolling grain boundaries so as to refine austenite grains. Higher N combines with Al in the steel to easily form AIN, thereby significantly increasing the number of nitrides in the steel. When AIN independently exists in steel as a non-metallic inclusion, the continuity of a steel matrix is damaged, and particularly when the AIN is formed in a large quantity and in an aggregation distribution manner when the Al content is high, the damage degree is higher, and oxides with poor plasticity are formed; and higher N tends to concentrate at the defect site, deteriorating low temperature impact toughness. The N content must be controlled to 0.0050% or less. The addition of Ti and N ensures that Ti/N is more than or equal to 3.42, and Ti completely fixes N, so that Nb and V can form enough carbide strengthening.
The strengthening mechanism of steel includes solid solution strengthening, phase transformation strengthening, fine crystal strengthening, precipitation strengthening, dislocation strengthening, and the like. Solid solution strengthening produces a strengthening effect by causing the ferrite lattice to deform in the c-axis direction due to the interstitial atoms being solid-dissolved in the ferrite lattice and a strengthening effect by a stress field affecting dislocations by the substitutional atoms being solid-dissolved in the ferrite lattice. Fine grain strengthening improves the grain boundary area and improves the strength through grain refinement; the precipitation strengthening is to precipitate movable dislocation of nail rolling by carbon nitride and block the dislocation movement to realize the improvement of strength; dislocation strengthening is to form dislocation walls and dislocation bands in crystal grains by improving the dislocation density in steel so as to block the movement of dislocations to generate a strengthening effect; while the phase transformation strengthening increases the strength by forming a phase with higher hardness such as bainite and martensite. The lattice constant of the material is changed during interstitial solid solution strengthening, and the resistance of dislocation motion is obviously increased, so that the strengthening effect is obvious.
The invention adopts a C-Mn component system, and strictly limits the components to be 0.24-0.26% and 1.15-1.25%, wherein the addition of C can realize martensite transformation strengthening through heat treatment, and Mn has the effects of solid solution strengthening and structure refinement. The content is low and can not reach the required target strength, and the content is too high and is unfavorable for welding, fatigue, toughness and the like. The Si content of the steel grade is limited to be below 0.25 percent so as to further improve the welding performance; meanwhile, noble alloy elements such as Cr and Ni are not added, the corrosion resistance functions of the two elements are not needed in the high-strength steel, and the solid solution strengthening and structure refining functions of the high-strength steel are respectively replaced by Mn and a small amount of Mo, Nb, V and Ti. The steel of the invention is added with a small amount of microalloy such as Nb, V, Ti and the like, and takes V as the main part (0.045-0.055%) and Nb and Ti (less than 0.025%) as the auxiliary parts. The V is low in cost, the high Ti is unfavorable for impact toughness, the composition can further reduce the manufacturing cost on one hand, and meanwhile, the composition combines control rolling to realize sufficient fine-grain strengthening and precipitation strengthening effects on a steel matrix structure in the hot rolling process.
The comprehensive application of Nb, Ti and V enlarges the temperature range of the unrecrystallized austenite of the steel grade, and creates conditions for fully refining the matrix structure by carrying out multi-pass deformation accumulation on austenite grains in the rolling deformation process. By controlling the deformation and the rolling temperature, the fine grain strengthening and the precipitation strengthening of the microalloy carbonitride are realized. The microalloy elements, C and a small amount of N form a large amount of nano-scale carbonitride in steel, and the carbonitride is precipitated in the austenite and controlled rolling process to play a role in refining a matrix structure. When the Ti content in the steel is less than 0.02 percent, TiN particles with the size of less than 20nm can be formed in austenite, the growth of an austenite structure is well inhibited, and the steel is still quite stable in the whole subsequent processing process (such as heating, hot rolling, welding and the like), so that the hot rolled steel plate has fine intrinsic grain size, and the carbonitride particles continuously play the roles of fine grain strengthening and precipitation strengthening in the subsequent heat treatment process. Particularly, 0.045-0.055% of V is added into the steel, a precipitated phase of the V is mainly VC under the condition of low nitrogen, the strengthening capability of the V is in direct proportion to the content, the V has a good strengthening effect, and the overall strengthening effect is better by combining the grain refining effect of 0.015-0.025% of Nb. V can inhibit the formation of non-polygonal ferrite, is beneficial to improving the martensite content in the quenching process and promotes the phase transformation strengthening; mo (0.25-0.45%) added to steel improves hardenability and promotes phase transformation strengthening effect, and simultaneously improves low-temperature toughness by cooperating with Mn, and carbide formed by the Mo and the Mn has solid solution strengthening effect.
According to the invention, the high-strength steel plate with the yield strength of more than 1300MPa is prepared by optimizing the component system and fully utilizing the action of each alloy element. The steel grade designed by the components obtains a high-strength martensite structure after controlled rolling and off-line heat treatment, and has high strength and good toughness, plasticity and straightness. The yield strength is more than or equal to 1300MPa, the tensile strength is more than or equal to 1500MPa, the elongation is more than or equal to 8 percent, the impact power value at minus 40 ℃ is more than or equal to 27J (full-size test sample), the straightness meets the requirement of less than or equal to 3mm/m, the cold bending meets the requirements of D being 8a and 90 degrees, and the cold-forming die has good forming performance and is suitable for the field of engineering machinery.
The manufacturing method of the ultra-high strength steel plate comprises the following steps:
1) smelting and casting
According to the components, firstly, the molten iron is deeply subjected to S removal, and the top and the bottom of a converter are subjected to combined blowing, external refining and continuous casting to form a plate blank;
2) slab reheating
The heating temperature is above 1230 ℃, the heat preservation time of the heating section is above 2h, wherein the soaking heat preservation time is not less than 40 min;
3) controlled rolling
The rolling is divided into two stages of rough rolling and finish rolling; rolling with large reduction in the rough rolling stage, controlling pass reduction rate to be more than 18% or pass reduction to be more than 40mm, and simultaneously requiring that the thickness ratio of the intermediate blank to the finished product is more than or equal to 5; and controlling the reduction rate of the last pass of finish rolling to be not less than 16 percent; the starting temperature of finish rolling is controlled to be above 960 ℃, and the finishing temperature is controlled to be above 850 ℃;
4) controlled cooling, coiling, uncoiling, straightening and cutting plate
The coiling temperature is controlled to be 580 +/-50 ℃; uncoiling and straightening a steel coil cooled to room temperature, and then cutting the steel coil into plates;
5) quenching and tempering treatment
The quenching heating temperature is 870 +/-20 ℃, the heat preservation time is calculated from the center of the steel plate to the temperature, the quenching heat preservation time T1 is 1.5-2 times of the thickness H of the steel plate, T1 is more than or equal to 4min, T1 is unit min; plate thickness, H, unit mm; directly carrying out water quenching on the steel plate after the steel plate is taken out of the furnace to room temperature, and controlling the cooling speed to be more than or equal to 20 ℃/s;
the tempering temperature is 200-240 ℃, the tempering heat preservation time is counted from the center of the steel plate to the temperature, the tempering heat preservation time T2 is 1.5-2.5 times of the thickness H of the steel plate, T2 is more than or equal to 6min, T2 is unit min; the thickness H of the steel plate is unit mm;
6) the quenched and tempered steel sheet is subjected to finishing treatment and delivered.
In the method for producing the steel of the present invention:
the casting blank is heated and insulated before rolling, the heating temperature is required to be above 1230 ℃ considering that steel contains micro-alloy elements such as Nb, V, Ti and the like, and the insulation time is above 2h in the heating section, so that the micro-alloy compounds can be fully dissolved. Wherein the soaking and heat preservation time is not less than 40 min. In addition, the casting blank can be hot-charged into the furnace after the casting is finished, namely the casting blank is directly conveyed to the heating furnace for heating and heat preservation from the casting area through the roller way after the fact that the surface of the casting blank has no quality problem is confirmed, so that the energy consumption can be reduced; if the casting blank can not be hot-charged, the cast blank must be placed in a heat preservation pit for slow cooling, and the heat preservation pit can be removed for air cooling after the temperature is reduced to below 200 ℃.
The rolling is divided into two stages of rough rolling and finish rolling. In order to obtain fine original austenite grain size, a casting blank is rolled by adopting large reduction in a rough rolling stage, and the pass reduction rate is controlled to be more than 18% or the pass reduction is controlled to be more than 40 mm. In order to obtain fine grain size and good plate shape, the thickness ratio of the intermediate blank to the finished product is required to be more than or equal to 5, and the reduction rate of the final pass of finish rolling is controlled to be not less than 16%. The steel billet is deformed enough in the austenite recrystallization temperature range, the microalloy plays a role in retarding the austenite dynamic recrystallization in the deformation process, and the deformed austenite is gradually refined through repeated rolling and recrystallization.
The invention relates to a method for realizing grain refinement and precipitation strengthening of a matrix of steel mainly by controlling deformation and rolling temperature in the rolling stage. From the continuous transition curve of fig. 1, the a → γ transition point of the steel grade is about 810 ℃, so that a finish rolling temperature of 850 ℃ or higher is recommended. At this temperature, V carbonitride is completely dissolved in solid solution, and Nb carbonitride is also mostly in solid solution, thereby ensuring that a large amount of carbonitride is precipitated in the cooling process after the rolling is completed, and playing a role in refining grains. According to the finish rolling temperature and the temperature drop in the finish rolling process, the finish rolling starting temperature is determined to be not lower than 920 ℃, and particularly, the finish rolling starting temperature is required to be controlled to be above 960 ℃ in consideration of the temperature drop of the intermediate billet in the finish rolling process. The invention relates to a steel grade having an austenite non-recrystallization temperature of about 993 ℃, meaning that the strip is in the austenite non-recrystallization temperature range throughout the finish rolling stage. In the temperature range from Ar3 to austenite non-recrystallization temperature, austenite recrystallization is inhibited, strain is accumulated, slender austenite grains are formed, high-density dislocation is generated in a deformation zone, microalloy solid solution atoms are precipitated into carbonitride through deformation induction, grains are refined, and fine intrinsic grain size is formed.
Because the subsequent off-line heat treatment is needed, the invention relates to the fact that the cooling stopping temperature of the steel grade is controlled to be higher than the martensite phase transformation starting temperature. As shown in FIG. 1, the martensite start transformation temperature of the steel grade is about 410 ℃, the coiling temperature is recommended to be controlled within 580 +/-50 ℃ in combination with the equipment capacity and the effective temperature measurement range in the hot rolling process, and if the coiling temperature is too high, the cooling speed is too low, so that the fine intrinsic grain size cannot be obtained by coarsening the crystal grains; the lower the take-up load increases.
And uncoiling and straightening the steel coil cooled to room temperature, then cutting the steel coil into plates, and quenching and tempering the steel plate. The quenching heating temperature directly influences the granularity of the subsequent martensite structure, and further influences the toughness of the steel plate. The austenite grains are easy to coarsen due to the overhigh heating temperature, the martensite structure is coarse after quenching, and the toughness is deteriorated; and the heating temperature is lower, so that austenitizing is insufficient, solid solution of micro-alloy elements is insufficient, a complete martensite structure cannot be obtained after quenching, and the effects of precipitation and fine grain strengthening of the micro-alloy are realized. In order to ensure that the carbonitride formed by Nb, V and Ti is dissolved as much as possible in the heat treatment heating process, the heating temperature is controlled according to the solid solubility formula. For example, Nb, according to the solid solubility formula Lg [ Nb ] [ C ] ═ 2.96-7510/T +0.248[ Mn ], and both V and Ti have similar formulas. And simultaneously, the quenching heating temperature of the steel grade is 870 +/-20 ℃ by combining the Ac3 temperature point of the steel grade, so that the sufficient solid solution of the carbonitride is ensured, and the martensite phase transformation strengthening, the precipitation strengthening of the microalloy and the fine grain strengthening are realized in the subsequent quenching and cooling process.
The heat preservation time has a similar rule to the quenching performance, crystal grains are easy to be large if the time is too long, energy consumption is increased, cost is improved, austenitizing is insufficient if the time is too short, and the hardness and strength after quenching cannot meet the requirements. The heat preservation time is required to be 1.5-2 times (min) of the thickness (mm) of the steel plate from the center of the steel plate to the temperature, but the minimum time is not less than 4 min. Directly water-quenching the steel plate to room temperature after discharging, and controlling the cooling speed to be more than or equal to 20 ℃/s according to the phase change transformation curve shown in figure 1.
The tempering treatment mainly slows down and eliminates the quenching stress and improves the toughness and the toughness. The higher tempering temperature easily causes the strength and hardness of the steel plate to be reduced too much, so that the design requirements cannot be met, and meanwhile, the cost is increased. The tempering process parameters of the steel sheet should be limited. In the invention, the steel plate is tempered in the temperature range of 200-240 ℃, and the tempering heat preservation time is 1.5-2.5 times (min) of the plate thickness (mm) from the center of the steel plate to the beginning of the temperature, but the minimum time is not less than 6 min. And finally, finishing (straightening and trimming) the quenched and tempered steel plate, controlling the unevenness to be less than or equal to 3mm/m, and leaving the factory after the mechanical properties are qualified.
The method can realize the production of the thin high-strength steel plate with the thickness of 2.5-6 mm. The yield strength of the steel plate is more than 1300MPa, the tensile strength exceeds 1500MPa, the elongation is more than or equal to 8 percent, and the impact power value at the temperature of minus 40 ℃ exceeds 27J, so that the bending requirements of D-8 a and 90 degrees are met, the forming performance is excellent, and the flatness is good.
The difference between the invention and the prior art is that:
the content of C in the steel grade in the Chinese patent publication No. CN102534423A 'high-strength steel plate and manufacturing method thereof' is 0.26-0.35%, which is higher than 0.24-0.26% (not containing upper limit value) required by the invention, which causes the carbon equivalent to be very high, and the welding performance is deteriorated; meanwhile, Cr and Ni are required to be added, the upper limit of the components respectively reaches 1.0 percent and 2.0 percent, the cost is obviously increased, Cr and Ni are not contained in the alloy, and the addition amount of Mo is obviously lower. Therefore, the method is obviously different from the method, and the thick plate process efficiency is lower.
In Chinese patent publication No. CN102337480A, "ultra-high strength steel plate with excellent environmental brittleness resistance and fatigue performance and manufacturing method thereof", both C, Si and Mn are higher than those of the invention, particularly, Si content is up to 1.5-1.9%, and noble alloy elements Cr and Ni are required to be added; meanwhile, the yield strength level is only 1150MPa level which is lower than or equal to 1300MPa required by the invention, so that the method has obvious difference.
Chinese patent publication No. CN102884218A, "high strength steel sheet and method for manufacturing the same", not only has higher contents of C, Si, and Mn, but also needs to add Al whose upper limit is 3.0%, and simultaneously, the contents of Cr and Ni are respectively as high as 0.8% and 5.0%, on one hand, the carbon equivalent is high, welding is difficult, and the cost is high, and simultaneously, the production process is complicated, and repeated heat treatment is required, and the production difficulty is high. The application in the field of engineering machinery is difficult to meet, and the method has great difference with the method.
The invention has the following advantages:
the invention adopts simple and economic C-Mn component design, is assisted by a small amount of Mo and microalloy elements such as Nb, V, Ti, B and the like, and realizes high strength and high toughness of steel grades through microalloy fine grain strengthening and phase change strengthening.
The steel grade has good low-temperature impact toughness, forming performance and flatness, and meets the use requirements of the steel for engineering machinery.
The invention relates to a steel grade with simple production process and low content of noble alloy elements, which reduces the production difficulty and the production cost and is beneficial to the large-scale popularization of the steel grade.
Drawings
FIG. 1 is a schematic diagram of CCT curve (calculation) of steel grade according to the invention.
In the figure, M is martensite, B is bainite, F is ferrite, and P is pearlite.
Detailed Description
The present invention will be further described with reference to the following examples.
The manufacturing process of the embodiment of the invention comprises the following steps: the method comprises the following steps of iron water deep stripping S (ensuring low S content in steel) → converter top and bottom combined blowing (controlling C content) → external refining → continuous casting (mechanical cleaning) → slab reheating → controlled rolling → controlled cooling → coiling → uncoiling → straightening → cutting plate → heat treatment (quenching + tempering) → finishing → delivery.
According to the chemical component requirements of the high-strength steel plate, steel plates with different thickness specifications are prepared. The chemical components are shown in table 1, the heating temperature of the steel billet is 1240 ℃, the finishing temperature is 880 ℃, and the steel billet is cooled to 550 ℃ after rolling and coiled; and cutting the steel coil after straightening, and quenching and tempering the steel plate. The heating temperature is 890 +/-20 ℃, and the tempering temperature is 200-. The specification and performance of the high-strength steel plate produced this time are shown in table 2.
TABLE 1 units wt%
| Numbering | C | Si | Mn | P | S | Al | N | Ti | V | Nb | Mo | B | Ca |
| A | 0.248 | 0.12 | 1.13 | 0.008 | 0.0024 | 0.028 | 0.0031 | 0.022 | 0.045 | 0.012 | 0.21 | 0.0045 | 0.0014 |
| B | 0.243 | 0.25 | 1.23 | 0.012 | 0.0035 | 0.034 | 0.0044 | 0.015 | 0.054 | 0.024 | 0.43 | 0.0017 | 0.0018 |
| C | 0.254 | 0.22 | 1.24 | 0.013 | 0.0036 | 0.042 | 0.0038 | 0.024 | 0.033 | 0.018 | 0.28 | 0.0038 | 0.0028 |
| D | 0.257 | 0.14 | 1.18 | 0.009 | 0.003 | 0.036 | 0.0033 | 0.018 | 0.048 | 0.022 | 0.30 | 0.0014 | 0.0024 |
TABLE 2 Steel plate Specifications and mechanical Properties
As can be seen from the above table 2, the yield strength of the steel plate is above 1300MPa, the elongation is more than or equal to 8%, the plasticity is excellent, and the low-temperature impact value meets the requirement (full-size sample) that the temperature is-40 ℃ and more than or equal to 27J; meanwhile, the steel plate has good flatness and forming performance, and is suitable for the field of engineering machinery.
Claims (4)
1. The ultrahigh-strength steel plate comprises the following components in percentage by weight: c: 0.24-0.26%, Si: 0.1-0.25%, Mn: 1.15-1.25%, P is less than or equal to 0.015%, S is less than or equal to 0.005%, Al: 0.015 to 0.025%, Mo: 0.25-0.45%, B: 0.001-0.005% and less than or equal to 0.004% of N; nb: 0.015 to 0.025%, Ti: 0.01-0.025%, V: 0.045-0.055%, and the balance of Fe and inevitable impurities;
the yield strength of the ultrahigh-strength steel plate is more than or equal to 1300MPa, the tensile strength is more than or equal to 1500MPa, the elongation is more than or equal to 8 percent, the impact power value at minus 40 ℃ is more than or equal to 27J, the straightness meets the requirement of less than or equal to 3mm/m, and the cold bending meets the requirement of D being 8a and 90 degrees.
2. The method of manufacturing an ultra high strength steel sheet according to claim 1, comprising the steps of:
1) smelting and casting
The composition of claim 1, wherein the molten iron is first deep-drawn to remove S, and then undergoes top-bottom combined blowing in a converter, external refining and continuous casting to form a slab;
2) slab reheating
The heating temperature is above 1230 ℃, the heat preservation time of the heating section is above 2h, wherein the soaking heat preservation time is not less than 40 min;
3) controlled rolling
The rolling is divided into two stages of rough rolling and finish rolling; rolling with large reduction in the rough rolling stage, controlling pass reduction rate to be more than 18% or pass reduction to be more than 40mm, and simultaneously requiring that the thickness ratio of the intermediate blank to the finished product is more than or equal to 5; and controlling the reduction rate of the last pass of finish rolling to be not less than 16 percent; the starting temperature of finish rolling is controlled to be above 960 ℃, and the finishing temperature is controlled to be above 850 ℃;
4) controlled cooling, coiling, uncoiling, straightening and cutting plate
The coiling temperature is controlled to be 580 +/-50 ℃; uncoiling and straightening a steel coil cooled to room temperature, and then cutting the steel coil into plates;
5) quenching and tempering treatment
The quenching heating temperature is 870 +/-20 ℃, the heat preservation time is calculated from the center of the steel plate to the temperature, the quenching heat preservation time T1 is 1.5-2 times of the thickness H of the steel plate, T1 is more than or equal to 4min, T1 is unit min; plate thickness, H, unit mm; directly carrying out water quenching on the steel plate after the steel plate is taken out of the furnace to room temperature, and controlling the cooling speed to be more than or equal to 20 ℃/s; the tempering temperature is 200-240 ℃, the tempering heat preservation time is counted from the center of the steel plate to the temperature, the tempering heat preservation time T2 is 1.5-2.5 times of the thickness H of the steel plate, T2 is more than or equal to 6min, T2 is unit min; the thickness H of the steel plate is unit mm;
6) the quenched and tempered steel sheet is subjected to finishing treatment and delivered.
3. The method of manufacturing an ultra high strength steel plate according to claim 2, wherein the slab is slowly cooled by placing the slab in a holding pit if the slab cannot be charged into the furnace by heating, and the slab is cooled by removing the holding pit after the temperature is lowered to 200 ℃.
4. The method for manufacturing the ultra-high strength steel plate according to claim 2, wherein the yield strength of the ultra-high strength steel plate is not less than 1300MPa, the tensile strength is not less than 1500MPa, the elongation is not less than 8%, the impact strength at-40 ℃ is not less than 27J, the flatness meets the requirement of not more than 3mm/m, and the cold bending meets the requirements of D-8 a and 90 degrees.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011052321A (en) * | 2009-08-06 | 2011-03-17 | Jfe Steel Corp | High-strength hot-rolled steel sheet having excellent low temperature toughness and method for producing the same |
| JP2014208884A (en) * | 2013-03-29 | 2014-11-06 | Ｊｆｅスチール株式会社 | High strength hot rolled steel sheet and method for producing the same |
| JP6167722B2 (en) * | 2013-07-23 | 2017-07-26 | 富士通株式会社 | Storage system, storage control device, and data transfer method |
Family Cites Families (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58164721A (en) * | 1982-03-24 | 1983-09-29 | Kobe Steel Ltd | Manufacture of structural steel with high toughness and strength |
| JPS6167722A (en) * | 1984-09-11 | 1986-04-07 | Kawasaki Steel Corp | Manufacture of cold rolled steel plate of high intensity and rolling by continuous annealing |
| JPH0830212B2 (en) * | 1990-08-08 | 1996-03-27 | 日本鋼管株式会社 | Manufacturing method of ultra high strength cold rolled steel sheet with excellent workability |
| US9999918B2 (en) * | 2005-10-20 | 2018-06-19 | Nucor Corporation | Thin cast strip product with microalloy additions, and method for making the same |
| CN102373368A (en) * | 2010-08-23 | 2012-03-14 | 宝山钢铁股份有限公司 | Steel for petroleum casing pipe and manufacturing method thereof |
| CN103361546A (en) * | 2012-03-30 | 2013-10-23 | 鞍钢股份有限公司 | Ultra-high strength binding belt raw plate and manufacturing method thereof |
| CN102676922B (en) * | 2012-05-11 | 2015-01-21 | 莱芜钢铁集团有限公司 | Low-alloy wear-resistant steel and manufacturing method thereof |
| CN102676924A (en) * | 2012-06-12 | 2012-09-19 | 钢铁研究总院 | Ultra-fine grained martensite steel plate and preparation method thereof |
| CN103510017A (en) * | 2012-06-19 | 2014-01-15 | 天津世通钢铁有限责任公司 | Ultrahigh-strength light armor plate and manufacturing method thereof |
| CN102747303B (en) * | 2012-06-29 | 2015-01-21 | 宝山钢铁股份有限公司 | High-strength steel sheet with yield strength of 1100MPa and manufacturing method thereof |
| CN103266269B (en) * | 2013-05-15 | 2015-04-22 | 武汉钢铁(集团)公司 | HB500 grade hot continuous rolling high strength wear-resisting steel and production method thereof |
| CN105274431B (en) * | 2014-06-09 | 2017-08-11 | 鞍钢股份有限公司 | Hot-rolled strip steel rake sheet suitable for water quenching and manufacturing method thereof |
| CN105296866B (en) * | 2014-06-09 | 2017-09-26 | 鞍钢股份有限公司 | Steel for blade, production method and blade treatment method |
| CN104532156B (en) * | 2014-12-19 | 2019-04-23 | 宝山钢铁股份有限公司 | A kind of yield strength 1300MPa grades of quenching and tempering, highs and its production method |
| CN106498295A (en) * | 2016-11-17 | 2017-03-15 | 哈尔滨光霞金属材料有限公司 | High-strength abrasion-proof steel and its manufacture method |
| CN107760988A (en) * | 2017-09-26 | 2018-03-06 | 河钢股份有限公司邯郸分公司 | The production method of low cost S EW oil casing steels |
| CN108570542B (en) * | 2018-05-15 | 2020-02-21 | 首钢集团有限公司 | Method for manufacturing steel for high-strength oil well pipe |
| CN108517465B (en) * | 2018-05-15 | 2019-06-28 | 马钢(集团)控股有限公司 | A kind of niobium titanium chromium-boron alloy abrasion-resistant stee and preparation method thereof |
-
2018
- 2018-09-28 CN CN201811141663.XA patent/CN109207851B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2011052321A (en) * | 2009-08-06 | 2011-03-17 | Jfe Steel Corp | High-strength hot-rolled steel sheet having excellent low temperature toughness and method for producing the same |
| JP2014208884A (en) * | 2013-03-29 | 2014-11-06 | Ｊｆｅスチール株式会社 | High strength hot rolled steel sheet and method for producing the same |
| JP6167722B2 (en) * | 2013-07-23 | 2017-07-26 | 富士通株式会社 | Storage system, storage control device, and data transfer method |
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