CN119800218A - A high-strength low-temperature impact-resistant cold-rolled ultra-low carbon steel and a preparation method thereof - Google Patents
A high-strength low-temperature impact-resistant cold-rolled ultra-low carbon steel and a preparation method thereof Download PDFInfo
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Abstract
本发明公开了一种高强度耐低温冲击冷轧超低碳钢及其制备方法，包括以下质量百分比的组分：C：0.0020％～0.0040％，Si：≤0.20％，Mn：0.5％～0.8％，P：0.050％～0.080％，S≤0.010％，Nb：0.020％～0.050％，Ti≤0.008％，B≤0.0009％，以及余量为铁和不可避免的杂质。本发明对全流程多工序的工艺耦合式技术参数进行设计，通过“铁水预处理+转炉冶炼+RH精炼+连铸+热轧+冷轧+退火”的生产工艺配合合金成分设计，不但确保强度水平380MPa的高强度的同时，还能确保低于‑80℃的情况下进行冲击时仍然保持产品的完整性，有利于北极等地极端严寒天气使用。
The present invention discloses a high-strength low-temperature impact-resistant cold-rolled ultra-low carbon steel and a preparation method thereof, comprising the following components in mass percentage: C: 0.0020% to 0.0040%, Si: ≤0.20%, Mn: 0.5% to 0.8%, P: 0.050% to 0.080%, S≤0.010%, Nb: 0.020% to 0.050%, Ti≤0.008%, B≤0.0009%, and the balance is iron and unavoidable impurities. The present invention designs the process coupling technical parameters of the whole process and multiple processes, and through the production process of "molten iron pretreatment + converter smelting + RH refining + continuous casting + hot rolling + cold rolling + annealing" with alloy composition design, it not only ensures the high strength of the strength level of 380MPa, but also ensures that the integrity of the product is maintained when impacting at a temperature below ‑80°C, which is conducive to use in extremely cold weather in the Arctic and other places.
Description
Technical Field
The invention relates to the technical field of materials and metallurgy, in particular to high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel and a preparation method thereof.
Background
At present, cold-rolled ultra-low carbon steel is widely applied to vehicle bodies, such as 170P1, HC220Y, 250P1, DC04, DC06 and the like, and the steel types are widely applied to vehicle body front cover plates, deep-drawing parts such as automobile instrument panels and the like and vehicle body covering parts with complex punching.
The low-temperature impact resistant temperature of the existing phosphorus-containing ultra-low carbon steel is detected to be 0 ℃, but impact brittle fracture is easy to occur when the temperature is lower than 0 ℃, because the binding force of a grain boundary is rapidly reduced after low-temperature freezing of the temperature is lower than 0 ℃, so that the limitation of impact fracture when the temperature is lower than 0 ℃ is triggered, a plurality of low-temperature impact fracture problems occur in the application process of customers, head-tail rolling brittle fracture is easy to occur in the cold rolling production process of the ultra-low carbon steel in winter, a great amount of cold rolling cutting loss is caused, and the follow-up application of an automobile host factory is influenced. Therefore, for the production method and the use method of the low-temperature impact resistant ultralow-carbon steel, how to improve the low-temperature impact resistant capability of the cold-rolled ultralow-carbon steel becomes a crucial research direction, and provides a solid technical support for the new-generation automobile engineering.
In the prior art, china patent with the application number 202010572388.8 discloses a strip steel with the tensile strength of 340MPa and a production method, which have excellent secondary processing performance at low temperature, but the product cannot meet the requirement of 380MPa strength products, meanwhile, the Ti content of the invention is 0.02% -0.06%, a large amount of FeTiP is generated to reduce the strength and increase the cold brittleness of a steel plate, the low-temperature processing resistance is weaker, the B content is 0.0003% -0.0010%, more boride is generated, the hardenability of boron is strong to reduce the elongation of a cold plate product, in addition, the minimum R value of the invention is 1.7, the requirement of a vehicle enterprise on the R value is not less than 2.0, the invention is unfavorable for the application of complex stamping processing of customers and the like, and the stamping is easy to cause.
The China patent with the application number 202111329449.9 discloses a production method of a high-strength low-temperature impact-resistant phosphorus-containing high-strength steel belt, but the product does not have the capability of keeping the integrity of the product when being impacted at the temperature lower than-80 ℃, meanwhile, the Ti content of the invention is 0.02% -0.05%, a large amount of FeTiP is generated to reduce the strength and increase the cold brittleness of the steel belt, the low-temperature impact resistance is reduced, meanwhile, the B content is 0.0008% -0.0020%, a large amount of boride is generated, the hardenability of boron is high to reduce the extensibility of the cold plate product, the complex stamping processing and other applications are not facilitated, the stamping is easy to cause, meanwhile, feTiP and boride macromolecular structures occupy grain boundaries to form isolation layers, and no connecting bonds are formed, so that the low-molecular activity low grain boundary connectivity is poorer at the low temperature lower than 0 ℃, and the low-temperature impact embrittlement is easier to occur.
The invention discloses a production method of a low-temperature impact resistant cold-base structural galvanized steel strip, which is characterized in that the product is mainly a galvanized product, the application scene is different from that of a cold-rolled annealed product, so that the design starting point of components and process parameters is not consistent with the basic mechanism, the mechanical properties of the product are not disclosed, the mechanical properties are not in the same strength level as the invention only by analyzing the disclosed data, meanwhile, the low-carbon design C of the product is 0.02-0.06%, the processing extensibility is poor, the complex deformation and deep processing requirements cannot be met, and the low-temperature impact resistant capability of-80 ℃ is not met.
Therefore, the effect of adopting a single control method is not obvious for ultra-low carbon steel, and the inhibition is required to be carried out based on the coupling design of the whole-flow process, so that the exploration of the preparation method of the whole-flow multi-dimensional low-temperature impact resistance based on component design, steelmaking, hot rolling, cold rolling, acid rolling and annealing has great significance.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide the high-strength low-temperature impact-resistant cold-rolled ultralow-carbon steel and the preparation method thereof, the invention designs the process coupling type technical parameters of the whole process and multiple working procedures, and the production process of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing is matched with alloy component design, so that the cold-rolled product of the prepared ultralow-carbon steel still maintains the integrity of the product when being impacted respectively at 0 ℃ to below 80 ℃, the phenomenon of impact cold-brittle fracture does not occur, the phenomenon of impact cold-brittle fracture of the conventional ultralow-carbon steel products of various components is avoided, the impact-brittle fracture resistance of the conventional ultralow-carbon steel products in low temperature application is realized, and the alloy such as phosphorus, manganese, niobium and the like is added while the processing deformation capacity is increased, the elements form connecting bonds at grain boundaries to strengthen the connection, and meanwhile, two-phase particles NbCN refine grains to increase the product strength and strengthen the low-temperature impact resistance of the grain boundaries; in addition, the R value is more than or equal to 2.0, which is beneficial to manufacturing parts by deep drawing mode of complex deformation in customer processing.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
A high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel comprises the following components ：C：0.0020％～0.0040％,Si：≤0.20％,Mn：0.5％～0.8％,P：0.050％～0.080％,S≤0.010％,Nb：0.020％～0.050％,Ti≤0.008％,B≤0.0009％, in percentage by mass, and the balance of iron and unavoidable impurities.
The invention also discloses a preparation method of the high-strength low-temperature impact resistant cold-rolled ultralow-carbon steel, which comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing;
In the molten iron pretreatment, desulfurizing the molten iron until S is less than or equal to 0.003%, so as to obtain desulfurized molten iron;
In the converter smelting, the desulfurized molten iron is subjected to converter smelting and tapping;
In the RH refining, carrying out RH refining treatment on molten steel discharged from a converter in converter smelting;
In the continuous casting, continuously casting the molten steel subjected to the RH refining treatment to obtain a continuous casting blank;
In the hot rolling, the heating temperature is 1200-1260 ℃, the rough rolling outlet temperature and the finish rolling initial rolling temperature are 1040-1080 ℃, the hot rolling final rolling temperature is 910-970 ℃, the laminar cooling is set to a front section concentrated cooling mode, the coiling temperature is 680-760 ℃, the hot coil stacking mode is adopted for cooling after the process coiling, and the hot coil cooling rate is controlled to be 10-20 ℃ per hour, so that a hot rolled steel coil is obtained;
In the cold rolling, the hot rolled steel coil is subjected to cold rolling to a target thickness of 0.5 mm-2.0 mm after being subjected to acid washing;
And in the annealing process, continuously annealing the cold-rolled steel material to obtain the cold-rolled ultra-low carbon steel.
The implementation of the embodiment of the invention has the following beneficial effects:
(1) The control scheme of the production process of the cold-rolled ultra-low carbon steel with the low temperature impact resistance of 380MPa level provided by the invention breaks the current situation that the impact quality of the conventional ultra-low carbon steel is poor at the low temperature of less than or equal to 0 ℃, and provides the thought of improving the low temperature impact resistance of the ultra-low carbon steel through full-flow multi-step coupling design, so that the low temperature impact of-80 ℃ is not broken.
(2) The production process of the invention does not add extra manufacturing equipment, has the characteristics of low cost and high efficiency, is easy for industrialized batch production, has good application effect, can be industrially applied without other auxiliary equipment and special process equipment, simplifies the production process and reduces the production cost.
(3) The invention adopts Nb to strengthen the low-temperature impact resistance of the product in the form of microalloy two-phase particles by the component design and combining the process designs of steelmaking process, hot rolling process, acid rolling process, annealing process and the like, so that the cold-rolled product of the ultra-low carbon steel still keeps the integrity of the product without cold-embrittlement fracture under the condition of respectively impacting at 0 ℃ to below 80 ℃, simultaneously, the Ti content is controlled to be less than or equal to 0.008 percent, the B content is controlled to be less than or equal to 0.0009 percent, a large number of FeTiP educts and borides generated by Ti and B in the conventional low-temperature-resistant cold-rolled ultra-low carbon steel can be avoided to weaken the binding force of the grain boundary, the formation of a fracture layer during the ultra-low temperature of Ti and B is avoided, meanwhile, the cold-rolled ultra-low carbon steel product design of the invention is analyzed, the processing deformability is improved, meanwhile, alloy such as phosphorus, manganese, niobium and the like are added, the elements form a reinforcing bond at the grain boundary, the strength is improved, and a large number of NbCN tiny two-phase particles increase the application strength of the product strength to be more than 380MPa, the high-strength strong product requirement of the product is met, and the impact resistance of the product is improved under the low-temperature environment of the customer.
(4) The production method of the cold-rolled product with ultralow carbon and low temperature impact resistance is different from the prior process control on product development, and the design is carried out on the technological parameters of multiple procedures in a whole process, so that the control on the low temperature impact resistance of the cold-rolled ultralow carbon steel is realized, the cold-rolled ultralow carbon steel produced by the production method provided by the invention has the tensile strength of more than 380MPa and the yield strength of 260-320 MPa, the elongation of the cold-rolled ultralow carbon steel is 38-48% A 50, and the R value is more than or equal to 2.0. While the-60 ℃ impact did not break and the-80 ℃ impact did not break.
The cold-rolled ultra-low carbon steel not only ensures high strength with the strength level of 380MPa, but also ensures that the product integrity is still maintained when being impacted at the temperature lower than-80 ℃, is favorable for being used in severe weather of the polar ends such as the north poles, and meanwhile, the Ti content is less than or equal to 0.008 percent, the B content is less than or equal to 0.0009 percent and is the residual content, feTiP and boride generated by adding Ti and B are prevented from influencing the strength and the elongation, and the low-temperature impact resistance is improved.
Drawings
FIG. 1 is a graph showing the distribution of two-phase particles NbCN in steel according to example 1 of the present invention.
Detailed Description
The invention is further illustrated below in connection with specific examples, but is not limited in any way.
1. Chemical composition and mechanical properties
The invention discloses high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel which comprises the following components ：C：0.0020％～0.0040％,Si：≤0.20％,Mn：0.5％～0.8％,P：0.050％～0.080％,S≤0.010％,Nb：0.020％～0.050％,Ti≤0.008％,B≤0.0009％, in percentage by mass, and the balance of iron and unavoidable impurities.
Specifically, the action mechanism of each alloy component in the cold-rolled ultra-low carbon steel is as follows:
And C is 0.0020% -0.0040%, the design of ultra-low carbon is beneficial to increasing the ductility of the product, complex deformation application is performed, and meanwhile, the low-temperature impact resistance is increased. If the C content exceeds this range, a proper amount of two-phase particles NbCN cannot be produced, and the processability R of the product is affected while the low-temperature impact resistance of the product is affected.
The design of Si less than or equal to 0.20 percent is beneficial to increasing the ductility of the product, improving the R value of the product and increasing the low-temperature impact resistance. Si content exceeds the range, the content is excessive, the lattice distortion is caused, the lattice resistance effect cannot be achieved, and the processing extensibility of the product is affected.
Mn is 0.5% -0.8%, and the design is beneficial to increasing the tensile strength of the product and increasing the low-temperature impact resistance. Mn content exceeds the range, the effect of strengthening ferrite grains by the alloy cannot be achieved, and the processability of the product is affected.
P is 0.050% -0.080%, and the tensile strength can be greatly improved to more than 380 MPa. The P content exceeds the range, the effect of strengthening ferrite grains by the alloy cannot be achieved, and the processability of the product is affected.
Nb is 0.020% -0.050%, and a large amount of NbCN fine two-phase particles are generated in the steel to act and refine crystal grains, so that the connectivity of crystal boundaries is improved, the low-temperature impact resistance is improved, and the yield strength and the tensile strength are improved. When the Nb content exceeds this range, a proper amount of two-phase particles NbCN cannot be produced, which affects the low-temperature impact resistance of the product and also affects the processability of the product.
Furthermore, the Ti content is less than or equal to 0.008 percent, the B content is less than or equal to 0.0009 percent as a residual element, the obvious reduction of the strength and R value of high-strength IF steel caused by a large amount of FeTiP generated during the addition annealing of Ti is avoided, the influence of yield strength and elongation caused by the addition of B is avoided, the Ti content is less than or equal to 0.008 percent, the B content is less than or equal to 0.0009 percent, the aim is to avoid the formation of FeTiP and boride macromolecular structures to occupy grain boundaries, the formation of isolation layers does not form connecting bonds, the capability of the material for resisting low-temperature impact is reduced, and the R value of a product can be improved.
In a specific embodiment, the tensile strength of the cold-rolled ultra-low carbon steel is more than or equal to 380MPa, the yield strength is 260-320 MPa, the elongation A 50 is 38-48%, and the R value is more than or equal to 2.0.
In a specific embodiment, the cold rolled ultra low carbon steel is not broken by-60 ℃ impact and not broken by-80 ℃ impact.
2. Production process technology
The invention also discloses a preparation method of the high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel, which comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing, and specifically comprises the following steps:
(1) In the pretreatment of molten iron, the molten iron is desulfurized until S is less than or equal to 0.003 percent, and desulfurized molten iron is obtained. The method has the function of smelting various auxiliary material alloys in the later steelmaking treatment process, thereby controlling the powerful conditions for providing S component required by the finished product.
(2) In converter smelting, the desulfurized molten iron is subjected to converter smelting and tapping.
In one embodiment, the step (2) specifically comprises the step of carrying out converter smelting on the desulfurized molten iron. The method has the effects of heating, reducing C, P, S components in the base molten iron and providing powerful conditions for refining the smelting components required by the RH finished product.
(3) In RH refining, molten steel discharged from a converter is subjected to RH refining treatment.
In one embodiment, the step (3) specifically comprises the steps of carrying out RH refining treatment on molten steel discharged from a converter smelting process, wherein the RH in-station temperature is 1570-1620 ℃, the temperature rise amplitude is less than or equal to 25 ℃, the static time target is 35min, and the out-station temperature is 1580-1590 ℃. The method has the function of treating the molten steel with smelting components required by the finished product, treating the temperature suitable for casting the molten steel and providing powerful conditions for the quality of the casting blank meeting the requirements of customers. Defects such as increased inclusion and the like are easily caused when the temperature is out of the range.
(4) In continuous casting, molten steel subjected to RH refining treatment is subjected to continuous casting, and a continuous casting blank is obtained. The method has the function of molding molten steel and producing casting blanks meeting the quality required by customers.
In a specific embodiment, the step (4) specifically comprises the steps of controlling the baking temperature of a tundish to be more than 1150 ℃, controlling the superheat degree of molten steel of the tundish to be 25-45 ℃, adopting a long water gap from a ladle to the tundish and performing argon sealing protection, wherein the invasion depth of the long water gap is 150-350 mm, adopting a covering agent to cover the tundish at the depth of 210mm, enabling the molten steel of the tundish to weigh more than or equal to 18 tons, adopting a submerged water gap from the tundish to a crystallizer and adopting argon sealing protection, enabling the invasion depth of the crystallizer to be 120-220 mm, and carrying out hot delivery on a continuous casting blank.
(5) In the hot rolling, the heating temperature is 1200-1260 ℃, the rough rolling outlet temperature and the finish rolling initial rolling temperature are 1040-1080 ℃, the hot rolling final rolling temperature is 910-970 ℃, the laminar cooling is set to be in a front-stage concentrated cooling mode, the coiling temperature is 680-760 ℃, the hot coil stacking mode is adopted for cooling after the process coiling, and the hot coil cooling rate is controlled to be 10-20 ℃ per hour, so that the hot rolled steel coil is obtained.
Specifically, the precipitation of two-phase particles with reasonable specification and variety is promoted by a specific process in the stage of the hot rolling procedure, and the formation of textures favorable for low-temperature impact resistance is promoted. The hot rolling method comprises the steps of heating a casting blank to be fully heated at 1200-1260 ℃, enabling the internal temperature and the external temperature to be uniform, enabling the rough rolling outlet temperature and the finish rolling initial temperature to be 1040-1080 ℃, enabling hot rolling of products to be stable, enabling the final rolling temperature of hot rolling to be 910-970 ℃, enabling products to be rolled in an austenite region, enabling laminar cooling to be set into a front-stage concentrated cooling mode, enabling the grain refinement degree of the steel plate to be improved, enabling the coiling temperature to be 680-760 ℃, enabling the texture of beneficial stamping to be formed, enabling the complex processing capacity of the products to be improved, and meanwhile enabling the low-temperature impact resistance of the products to be improved, enabling hot coil stacking to be adopted for cooling after the process coiling, enabling the cooling rate of the hot coil to be controlled at 10-20 ℃ and enabling grain structures and textures of beneficial stamping to be formed, and enabling the complex processing capacity and the low-temperature impact resistance of the products to be improved.
(6) In the cold rolling, the hot rolled steel coil is subjected to cold rolling to a target thickness of 0.5 mm-2.0 mm after pickling.
In a specific embodiment, the step (6) specifically comprises the steps of stretching and straightening a hot rolled steel coil in cold rolling, wherein the elongation is 0.5% -0.8%, shallow groove turbulent pickling is carried out after straightening, the pickling temperature is 70 ℃ -90 ℃, the pickling speed is 180-230 m/min, and the deformation compression ratio of the steel plate after pickling is more than or equal to 60%.
Specifically, the cold rolling and pickling stage adopts the elongation of 0.5% -0.8% to carry out stretching straightening and shallow groove turbulent pickling to remove oxide scales, the cold rolled steel plate realizes a smooth surface, the cold rolled steel plate is beneficial to further application such as coating of clients, the hot rolled steel plate is rolled by a rolling mill to be a cold rolled hard steel belt, the crystal grains are crushed, the deformation compression ratio is more than or equal to 60%, the degree of crystal grain reduction of a cold rolled product is increased, the product is recrystallized after annealing to obtain refined crystal grains, the grain boundary binding force is increased, and the low-temperature impact resistance is improved.
(7) And in the annealing process, continuously annealing the cold-rolled steel material to obtain the cold-rolled ultra-low carbon steel.
In one embodiment, the step (7) specifically comprises the steps of heating the band steel at 760-850 ℃, soaking the band steel at 760-850 ℃, slowly cooling at 640-690 ℃, rapidly cooling at 450-500 ℃, aging at 440-490 ℃ and final cooling at 150-180 ℃.
Specifically, the annealing adopts a continuous annealing mode, the soaking temperature is set to 760-850 ℃, the aim is to re-dissolve precipitated and grown two-phase particles in steel, such as NbCN, and the like, and the grains are subjected to recrystallization texture development after rolling, at the moment, the elongation and R90 of the steel are slightly increased, and meanwhile, the low-temperature impact resistance is ensured, the slow cooling temperature is set to 640-690 ℃, the aim is to facilitate NbCN precipitation into fine two-phase particles, the development of recrystallization texture is hindered, at the moment, the yield strength, the tensile strength and the elongation of the steel are ensured, the low-temperature impact resistance is also ensured, the quick cooling temperature is set to 450-500 ℃, the aim is to further refine the grains, stabilize the precipitated phase and the grain structure, the aging stage temperature is set to 440-490 ℃, the fine NbCN two-phase particles in the grains are ensured to be precipitated, meanwhile, the annealing state recrystallization transformation of a cold-rolled product is completed, the increase of R90 ensures good stamping performance, and the cold brittleness resistance is not caused, the yield strength, the final temperature is set to 150-180 ℃, and the aim is not to regenerate the grain structure.
The following are specific examples
Example 1
The high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel comprises, by mass, 0.0028% of C, 0.124% of Si, 0.65% of Mn, 0.062% of P, 0.0042% of S, 0.0249% of Nb, 0.0008% of Ti, 0.0001% of B, and the balance of iron and unavoidable impurities.
The preparation method of the high-strength low-temperature impact resistant cold-rolled ultralow-carbon steel comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing, and specifically comprises the following steps:
(1) In the pretreatment of molten iron, the molten iron is desulfurized until S is less than or equal to 0.003 percent, and desulfurized molten iron is obtained.
(2) In converter smelting, the desulfurized molten iron is subjected to converter smelting.
(3) In RH refining, molten steel discharged from a converter is subjected to RH refining treatment, the RH in-station temperature is 1580 ℃, the temperature rise range is less than or equal to 25 ℃, the static time target is 35min, and the out-station temperature is 1583 ℃.
(4) In continuous casting, the baking temperature of the tundish is controlled to be 1150 ℃, the superheat degree of molten steel of the tundish is controlled to be 30 ℃, a long water gap is adopted from a ladle to the tundish and is subjected to argon sealing protection, the invasion depth of the long water gap is 220mmmm, the tundish is covered by a covering agent, the molten steel of the tundish weighs 26 tons, the immersed water gap is adopted from the tundish to a crystallizer and is subjected to argon sealing protection, the invasion depth of the crystallizer is 180mm, and a continuous casting billet is hot-fed.
(5) In the hot rolling, the heating temperature is 1235 ℃, the rough rolling outlet temperature is 1079 ℃, the finish rolling start temperature is 1068 ℃, the hot rolling finish rolling temperature is 923 ℃, the laminar cooling is set to a front-stage concentrated cooling mode, the coiling temperature is 701 ℃, the hot coil stacking mode is adopted for cooling after the process coiling, and the hot coil cooling rate is controlled at 17 ℃ per hour, so that the hot rolled steel coil is obtained.
(6) In the cold rolling process, the hot rolled steel coil is subjected to stretching straightening, the elongation is 0.7%, shallow groove turbulent acid washing is carried out after straightening, the acid washing temperature is 85 ℃, the acid washing speed is 200m/min, and the acid washed steel plate is rolled to a cold rolled hard steel belt, wherein the deformation compression ratio is more than or equal to 60%.
(7) In annealing, the cold-rolled steel material is continuously annealed, the annealing temperature of a heating section is 789 ℃, the annealing temperature of a soaking section is 803 ℃, the slow cooling temperature is 651 ℃, the quick cooling temperature is 455 ℃, the aging section is 443 ℃, and the final cooling temperature is 153 ℃.
Example 2
The high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel comprises, by mass, 0.0027% of C, 0.1351% of Si, 0.6755% of Mn, 0.06407% of P, 0.00539% of S, 0.0262% of Nb, 0.0008% of Ti, 0.0001% of B, and the balance of iron and unavoidable impurities.
The preparation method of the high-strength low-temperature impact resistant cold-rolled ultralow-carbon steel comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing, and specifically comprises the following steps:
(1) In the pretreatment of molten iron, the molten iron is desulfurized until S is less than or equal to 0.003 percent, and desulfurized molten iron is obtained.
(2) In converter smelting, the desulfurized molten iron is subjected to converter smelting.
(3) In RH refining, molten steel discharged from a converter is subjected to RH refining treatment, the RH in-station temperature is 1602 ℃, the temperature rise range is less than or equal to 25 ℃, the static time target is 35min, and the out-station temperature is 1581 ℃.
(4) In continuous casting, the baking temperature of a tundish is controlled to be 1201 ℃, the superheat degree of molten steel of the tundish is controlled to be 30 ℃, a long water gap is adopted from a ladle to the tundish and is subjected to argon sealing protection, the invasion depth of the long water gap is 201mm, the tundish is covered by a covering agent, the molten steel of the tundish is 25 tons, a submerged water gap is adopted from the tundish to a crystallizer and is subjected to argon sealing protection, the invasion depth of the crystallizer is 149mm, and a continuous casting billet is hot-fed.
(5) In the hot rolling, the heating temperature is 1243 ℃, the rough rolling outlet temperature is 1077 ℃, the finish rolling start temperature is 1073 ℃, the hot rolling finish rolling temperature is 923 ℃, the laminar cooling is set to a front-stage concentrated cooling mode, the coiling temperature is 702 ℃, the hot coil stacking mode is adopted for cooling after the process coiling, and the hot coil cooling rate is controlled at 12 ℃ per hour, so that the hot rolled steel coil is obtained.
(6) In cold rolling, the hot rolled steel coil is stretched and straightened to reach elongation of 0.6%, shallow groove turbulent acid washing is carried out after straightening, the acid washing temperature is 80 ℃, the acid washing speed is 227m/min, and the acid washed steel plate is rolled to a cold rolled hard steel belt with deformation compression ratio more than or equal to 60%.
(7) In annealing, the cold rolled steel material is continuously annealed, the annealing temperature of a heating section is 788 ℃, the annealing temperature of a soaking section is 800 ℃, the slow cooling temperature is 646 ℃, the quick cooling temperature is 450 ℃, the aging section is 448 ℃, and the final cooling temperature is 155 ℃.
Example 3
The high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel comprises, by mass, 0.0029% of C, 0.1369% of Si, 0.6552% of Mn, 0.06423% of P, 0.0037% of S, 0.0295% of Nb, 0.0006% of Ti, 0.0001% of B, and the balance of iron and unavoidable impurities.
The preparation method of the high-strength low-temperature impact resistant cold-rolled ultralow-carbon steel comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing, and specifically comprises the following steps:
(1) In the pretreatment of molten iron, the molten iron is desulfurized until S is less than or equal to 0.003 percent, and desulfurized molten iron is obtained.
(2) In converter smelting, the desulfurized molten iron is subjected to converter smelting.
(3) In RH refining, molten steel discharged from a converter is subjected to RH refining treatment, the RH in-station temperature is 1572 ℃, the temperature rise range is less than or equal to 25 ℃, the static time target is 35min, and the out-station temperature is 1589 ℃.
(4) In continuous casting, the baking temperature of the tundish is controlled to be 1189 ℃, the superheat degree of molten steel of the tundish is 33 ℃, a long water gap is adopted from a ladle to the tundish and is subjected to argon sealing protection, the invasion depth of the long water gap is 230mm, the tundish is covered by a covering agent, the molten steel of the tundish weighs 27 tons, a submerged water gap is adopted from the tundish to a crystallizer and is subjected to argon sealing protection, the invasion depth of the crystallizer is 177mm, and a continuous casting billet is hot-fed.
(5) In the hot rolling, the heating temperature is 1245 ℃, the rough rolling outlet temperature is 1068 ℃, the finish rolling start temperature is 1072 ℃, the hot rolling finish rolling temperature is 918 ℃, the laminar cooling is set to a front-stage concentrated cooling mode, the coiling temperature is 698 ℃, the hot coil stacking mode is adopted for cooling after the process coiling, and the hot coil cooling rate is controlled at 18 ℃ per hour, so that the hot rolled steel coil is obtained.
(6) In cold rolling, the hot rolled steel coil is stretched and straightened to reach elongation of 0.55%, shallow groove turbulent acid washing is carried out after straightening, the acid washing temperature is 78 ℃, the acid washing speed is 189m/min, and the acid washed steel plate is rolled to a cold rolled hard steel belt with deformation compression ratio more than or equal to 60%.
(7) In annealing, the cold-rolled steel material is continuously annealed, the annealing temperature of a heating section is 791 ℃, the annealing temperature of a soaking section is 805 ℃, the slow cooling temperature is 652 ℃, the quick cooling temperature is 453 ℃, the aging section is 440 ℃, and the final cooling temperature is 150 ℃.
Example 4
The high-strength low-temperature impact resistant cold-rolled ultra-low carbon steel comprises, by mass, 0.0032% of C, 0.131% of Si, 0.6816% of Mn, 0.063% of P, 0.0046% of S, 0.02655% of Nb, 0.0008% of Ti, 0.0001% of B, and the balance of iron and unavoidable impurities.
The preparation method of the high-strength low-temperature impact resistant cold-rolled ultralow-carbon steel comprises the following steps of molten iron pretreatment, converter smelting, RH refining, continuous casting, hot rolling, cold rolling and annealing, and specifically comprises the following steps:
(1) In the pretreatment of molten iron, the molten iron is desulfurized until S is less than or equal to 0.003 percent, and desulfurized molten iron is obtained.
(2) In converter smelting, the desulfurized molten iron is subjected to converter smelting.
(3) In RH refining, molten steel discharged from a converter is subjected to RH refining treatment, the RH in-station temperature is 1602 ℃, the temperature rise range is less than or equal to 25 ℃, the static time target is 35min, and the out-station temperature is 1588 ℃.
(4) In continuous casting, the baking temperature of a tundish is controlled to be 1209 ℃, the superheat degree of molten steel of the tundish is 27 ℃, a long water gap is adopted from a ladle to the tundish and is subjected to argon sealing protection, the invasion depth of the long water gap is 193mm, the tundish is covered by a covering agent, the molten steel of the tundish weighs 32 tons, a submerged water gap is adopted from the tundish to a crystallizer and is subjected to argon sealing protection, the invasion depth of the crystallizer is 172mm, and a continuous casting billet is hot-fed.
(5) In the hot rolling, the heating temperature is 1256 ℃, the rough rolling outlet temperature is 1075 ℃, the finish rolling starting temperature is 1080 ℃, the hot rolling finishing temperature is 918 ℃, the laminar cooling is set to a front-stage concentrated cooling mode, the coiling temperature is 709 ℃, the hot coil stacking mode is adopted for cooling after the technological coiling, and the hot coil cooling rate is controlled at 11 ℃ per hour, so that the hot rolled steel coil is obtained.
(6) In cold rolling, the hot rolled steel coil is stretched and straightened to reach elongation of 0.63%, shallow groove turbulent acid washing is carried out after straightening, the acid washing temperature is 87 ℃, the acid washing speed is 213m/min, and the acid washed steel plate is rolled to a cold rolled hard steel belt with deformation compression ratio more than or equal to 60%.
(7) In annealing, the cold rolled steel material is continuously annealed, the annealing temperature of a heating section is 795 ℃, the annealing temperature of a soaking section is 809 ℃, the slow cooling temperature is 655 ℃, the quick cooling temperature is 458 ℃, the aging section is 455 ℃, and the final cooling temperature is 156 ℃.
Test case
The cold rolled ultra low carbon steel prepared in examples 1 to 4 was subjected to low temperature impact resistance test and tensile impact test, and the results are shown in Table 1.
TABLE 1 Low temperature impact and tensile impact test results for examples 1-4
As can be seen from the embodiment, the production method of the cold-rolled ultra-low carbon steel with the low temperature impact resistance of 380MPa level can greatly improve the quality capability of the cold-rolled ultra-low carbon steel product on low temperature impact resistance.
The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (7)
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT8026376A0 (en) * | 1979-12-14 | 1980-12-02 | Nippon Kokan Kk | METHOD FOR THE PRODUCTION OF COLD ROLLED HIGH STRENGTH STEEL TAPE EXCELLENT IN PRESS FORMABILITY. |
| CN102925796A (en) * | 2012-10-30 | 2013-02-13 | 鞍钢股份有限公司 | Non-alloyed ultra-low carbon cold-rolled sheet for structure and production method thereof |
| CN109136755A (en) * | 2018-08-31 | 2019-01-04 | 包头钢铁（集团）有限责任公司 | A kind of automobile cold-rolled high strength steel and its production method |
| CN110172637A (en) * | 2019-03-29 | 2019-08-27 | 宁波钢铁有限公司 | A kind of 340MPa grades of deep-draw high-strength IF steel band and preparation method thereof |
| CN113151651A (en) * | 2020-09-25 | 2021-07-23 | 攀钢集团研究院有限公司 | A kind of production method of low-temperature annealing ultra-deep drawing cold-rolled steel sheet and cold-rolled steel sheet |
| CN114000060A (en) * | 2021-11-10 | 2022-02-01 | 山东钢铁集团日照有限公司 | Production method of high-strength low-temperature-impact-resistant phosphorus-containing high-strength steel strip |
| WO2022127104A1 (en) * | 2020-12-16 | 2022-06-23 | 江苏省沙钢钢铁研究院有限公司 | High-grade non-oriented silicon steel and production method therefor |
| CN115558838A (en) * | 2022-09-19 | 2023-01-03 | 包头钢铁（集团）有限责任公司 | Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control |
| CN117165845A (en) * | 2023-04-28 | 2023-12-05 | 鞍钢股份有限公司 | 340 MPa-level alloying hot dip galvanized sheet for new energy automobile and preparation method thereof |
-
2025
- 2025-01-03 CN CN202510011084.7A patent/CN119800218A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT8026376A0 (en) * | 1979-12-14 | 1980-12-02 | Nippon Kokan Kk | METHOD FOR THE PRODUCTION OF COLD ROLLED HIGH STRENGTH STEEL TAPE EXCELLENT IN PRESS FORMABILITY. |
| CN102925796A (en) * | 2012-10-30 | 2013-02-13 | 鞍钢股份有限公司 | Non-alloyed ultra-low carbon cold-rolled sheet for structure and production method thereof |
| CN109136755A (en) * | 2018-08-31 | 2019-01-04 | 包头钢铁（集团）有限责任公司 | A kind of automobile cold-rolled high strength steel and its production method |
| CN110172637A (en) * | 2019-03-29 | 2019-08-27 | 宁波钢铁有限公司 | A kind of 340MPa grades of deep-draw high-strength IF steel band and preparation method thereof |
| CN113151651A (en) * | 2020-09-25 | 2021-07-23 | 攀钢集团研究院有限公司 | A kind of production method of low-temperature annealing ultra-deep drawing cold-rolled steel sheet and cold-rolled steel sheet |
| WO2022127104A1 (en) * | 2020-12-16 | 2022-06-23 | 江苏省沙钢钢铁研究院有限公司 | High-grade non-oriented silicon steel and production method therefor |
| CN114000060A (en) * | 2021-11-10 | 2022-02-01 | 山东钢铁集团日照有限公司 | Production method of high-strength low-temperature-impact-resistant phosphorus-containing high-strength steel strip |
| CN115558838A (en) * | 2022-09-19 | 2023-01-03 | 包头钢铁（集团）有限责任公司 | Production method of ultra-deep drawing cold-rolled steel strip with low temper mill elongation rate control |
| CN117165845A (en) * | 2023-04-28 | 2023-12-05 | 鞍钢股份有限公司 | 340 MPa-level alloying hot dip galvanized sheet for new energy automobile and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 许姣姣: "极薄ＩＦ钢的连续退火工艺研究", 《四川冶金》, vol. 46, no. 3, 30 June 2024 (2024-06-30), pages 12 - 16 * |
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