High-strength steel, preparation method and application thereof and sliding rail for automobile

Abstract

The invention relates to high-strength steel, a preparation method and application thereof and a sliding rail for an automobile, and the high-strength steel comprises the following components in percentage by mass: 0.04%-0.1% of carbon, 0.1%-0.25% of silicon, 0.8%-1.3% of manganese, 0-0.005% of sulfur, 0-0.02% of phosphorus, 0.01%-0.035% of vanadium, 0.1%-0.15% of titanium, 0.02%-0.06% of acid-soluble aluminum, more than 0 and less than or equal to 0.007% of nitrogen, and the balance of Fe and inevitable impurity elements. The steel is small in isotropic difference, more uniform in structure distribution, high in strength and good in ductility.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and in particular to high-strength steel, a preparation method and application thereof, and a slide rail for automobiles. Background Art

[0002] In recent years, in order to meet the requirements of automobile lightweighting and energy conservation and emission reduction, various automobile parts are trying to reduce weight while maintaining high strength. As a result, steel has become one of the important materials for automobile parts. However, some of the automobile parts, which are precision parts, also need to have high dimensional accuracy and surface quality. For example, the slide rail is an important precision part on the car seat. The common slide rail is mainly installed under the seat. It is used to adjust the front, back, left and right positions. It needs to have several key characteristics: safety characteristics, connection characteristics, support characteristics and adjustment characteristics, that is, it requires both high strength and good elongation. However, traditional steel mainly highlights high strength performance. How to obtain steel with both high strength and good elongation is still a difficult problem to be overcome.

[0003] Therefore, the existing technology still needs to be improved. Summary of the invention

[0004] Based on this, the present invention provides a high-strength steel with high strength and good elongation, a preparation method and application thereof, and a slide rail for automobiles.

[0005] One aspect of the present invention provides a high-strength steel, wherein the components of the high-strength steel include, by mass percentage, 0.04% to 0.1% carbon, 0.1% to 0.25% silicon, 0.8% to 1.3% manganese, 0 to 0.005% sulfur, 0 to 0.02% phosphorus, 0.01% to 0.035% vanadium, 0.1% to 0.15% titanium, 0.02% to 0.06% acid-soluble aluminum, 0 < nitrogen ≤ 0.007%, and the remainder Fe and unavoidable impurity elements.

[0006] The yield strength of the high-strength steel may be greater than 800 MPa, the tensile strength may be greater than 830 MPa, and the elongation may be greater than 10%.

[0007] In some of the embodiments, the microstructure of the high strength steel includes ferrite, martensite, austenite and cementite.

[0008] In some embodiments, the high-strength steel has a thickness of 1.2 mm to 2 mm.

[0009] Another aspect of the present invention provides a method for preparing high-strength steel, comprising the following steps:

[0010] Providing raw materials according to the stoichiometric ratio of the components of the high-strength steel, and subjecting the raw materials to smelting and refining treatments in sequence to prepare an alloy melt;

[0011] The alloy melt is sequentially subjected to casting treatment, hot rolling treatment, cold rolling treatment and annealing treatment to obtain high-strength steel.

[0012] In the preparation method of the above-mentioned high-strength steel, the raw materials prepared according to the stoichiometric ratio of the above-mentioned high-strength steel are smelted and refined to form an alloy melt, and then after the casting process, they are hot rolled, cold rolled and annealed in sequence to obtain a hot-rolled pearlite structure. Subsequently, during annealing, particles with a strong strengthening effect are precipitated, the strength is improved, and the phase transformation stress is released, so that the isotropy difference of the steel is small, the structure distribution is more uniform, the performance difference at different locations is small, and it has both high strength and good elongation.

[0013] In some embodiments, before the refining step, the following steps are also included:

[0014] subjecting the alloy melt prepared through the smelting treatment to a ladle argon blowing treatment;

[0015] In the step of argon blowing treatment of the ladle, the temperature at the end of the argon station is controlled to be greater than 1542°C; and / or

[0016] The refining treatment is performed at a temperature of 1570° C. to 1590° C. and for a time of 40 minutes to 120 minutes.

[0017] In some embodiments, the hot rolling process comprises the following steps:

[0018] The cast slab is heated and then rolled: the starting rolling temperature is 1090° C. to 1150° C., and the final rolling temperature is 850° C. to 900° C.;

[0019] The heating time is not less than 25 minutes.

[0020] In some embodiments, the cold rolling treatment conditions include: controlling the single-pass reduction rate of a single stand to be ≥15%, 3 to 5 reciprocating rolling passes, and a rolling speed of 200 m / min to 350 m / min; and / or

[0021] The annealing treatment conditions include: using a bell-type annealing furnace to perform a hydrogen blowing system, and keeping the temperatures at 400° C., 520° C., and 600° C. for 2 hours, 2 hours, and 10 hours, respectively.

[0022] In some embodiments, after the hot rolling step and before the cold rolling step, the following steps are further included:

[0023] The slab after the hot rolling treatment is sequentially subjected to laminar cooling and pickling treatment; wherein the final cooling temperature of the laminar cooling is 590° C. to 640° C., and the speed of the pickling treatment is 30 m / min to 120 m / min; and / or

[0024] After the annealing step, the method further comprises the following steps:

[0025] The slab that has undergone the annealing treatment is flattened; wherein, during the flattening treatment, the rolling force is controlled to be 300±100 tons.

[0026] In the above preparation method, by further controlling the conditions of each rolling step, each specific component completes hardening measures such as solid solution strengthening, precipitation strengthening, dislocation strengthening, and fine grain strengthening. The grains of appropriate size are obtained by high-temperature deformation recrystallization of the austenite zone, deformation of the low-temperature austenite non-recrystallization zone, and laminar cooling after rolling. Annealing obtains a stable and uniform strengthened structure, thereby further improving the performance of the steel.

[0027] In another aspect of the present invention, there is also provided the use of the above-mentioned high-strength steel or the high-strength steel produced by the above-mentioned method for producing high-strength steel in the production of automobile parts.

[0028] In another aspect of the present invention, there is provided a slide rail for automobile, comprising the above-mentioned high-strength steel or the high-strength steel produced by the above-mentioned method for producing high-strength steel.

[0029] The above steel has small isotropy difference, more uniform tissue distribution, small performance difference in different places, high strength and good elongation. The thickness tolerance when made into steel plate is small and the control accuracy is high. When the target thickness is ≤2mm, the thickness accuracy can reach ±20μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a metallographic structure diagram of the surface layer of the high-strength steel coil prepared in Example 1;

[0031] Figure 2 This is a metallographic structure diagram of a cross section of 1 / 4 thickness of the high-strength steel coil prepared in Example 1;

[0032] Figure 3 This is the metallographic structure diagram of the cross section of 1 / 2 thickness of the high-strength steel coil prepared in Example 1. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below. Preferred embodiments of the present invention are provided in the specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0035] the term

[0036] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0037] The terms "and / or", "or / and", and "and / or" used in this article include any one of two or more related listed items, and also include any and all combinations of related listed items, and the arbitrary and all combinations include any combination of two related listed items, any more related listed items, or all related listed items. It should be noted that when at least three items are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it should be understood that in this application, the technical solution undoubtedly includes technical solutions that are all connected by "logical and", and undoubtedly includes technical solutions that are all connected by "logical or". For example, "A and / or B" includes three parallel solutions of A, B and the combination of A and B. For example, the technical solution of "A, and / or, B, and / or, C, and / or, D" includes any one of A, B, C, and D (that is, the technical solution that is all connected by "logical OR"), and also includes any and all combinations of A, B, C, and D, that is, the combination of any two or any three of A, B, C, and D, and also includes the combination of four of A, B, C, and D (that is, the technical solution that is all connected by "logical AND").

[0038] In the present application, when at least three features are connected by at least two conjunctions selected from "and / or", "or / and", and "and / or", it is equivalent to the expression "having one or more features", for example, "TA, and / or, TB, and / or, TC, and / or, TD" is equivalent to "having one or more of the following features: TA, TB, TC and TD".

[0039] In the present invention, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0040] As used herein, "combination thereof", "any combination thereof", "any combination thereof" etc. include all suitable combinations of any two or more of the listed items.

[0041] In the present invention, "optionally", "optional", and "optional" mean optional, that is, any one of the two parallel solutions of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0042] In the present invention, in the "first aspect", "second aspect", "third aspect", "fourth aspect", etc., the terms "first", "second", "third", "fourth", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0043] In the present invention, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0044] In the present invention, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, including the two endpoint integers of the numerical range, and each integer between the two endpoints, is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0045] The temperature parameters in the present invention, if not specifically limited, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the precision range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0046] In the present invention, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of the present invention, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of the present invention, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0047] The mass or weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass or weight described in the description of the embodiments of the present invention may be units known in the chemical industry such as μg, mg, g, and kg.

[0048] An embodiment of the present invention provides a high-strength steel, wherein the components of the high-strength steel are, by mass percentage, 0.04% to 0.1% carbon, 0.1% to 0.25% silicon, 0.8% to 1.3% manganese, 0 to 0.005% sulfur, 0 to 0.02% phosphorus, 0.01% to 0.035% vanadium, 0.1% to 0.15% titanium, 0.02% to 0.06% acid-soluble aluminum, 0 < nitrogen ≤ 0.007%, and the remainder Fe and unavoidable impurity elements.

[0049] The above-mentioned high-strength steel contains components in a specific ratio. Each specific element has its own advantages and disadvantages on various aspects of the steel performance. After a large number of creative experimental studies, it was found that carbon is an effective element to improve the strength of steel, but too high a C content will reduce low-temperature toughness and deteriorate welding performance and corrosion resistance; silicon can reduce the solubility of carbon in austenite, reduce the stability of supercooled austenite, accelerate the phase change process, play a role in solid solution strengthening, and at the same time improve the elongation of the steel plate and balance the strength and plasticity of the steel plate; manganese can improve hardenability and increase the strength of the material, but because Mn is a crystalline positive segregation element, it is easy to produce banded structure, so the Mn content should not be too high; sulfur is a harmful element in high-strength steel, which is easy to produce MnS segregation and sulfide inclusions, so it is necessary to control the sulfur content. On the one hand, it can reduce the number and size of sulfide inclusions, and at the same time, it can modify the morphology of sulfides (mainly MnS) to avoid long strips of sulfides and avoid stamping cracking; phosphorus: P element is also harmful in high-strength steel. Elements, although P combined with S and Mn can increase the cutting performance of steel and improve the surface quality of workpieces, but P element dissolves in ferrite. While improving the strength and hardness of steel, the biggest harm is serious segregation, increasing temper brittleness, significantly reducing the plasticity and toughness of steel, and causing steel to easily crack during cold working; vanadium is an excellent deoxidizer for steel. At a specific content, it can refine the grain size of the structure, improve the strength and toughness, and the carbide formed by vanadium and carbon can improve the resistance to hydrogen corrosion under high temperature and high pressure; aluminum element is conducive to promoting the formation of acicular ferrite, but too much aluminum will damage the toughness of steel, titanium combines with nitrogen to form TiN, the presence of TiN can inhibit the coarsening of grains in the heat affected zone of welding, and nitrogen can also combine with aluminum, vanadium and other elements to form extremely stable nitrides to achieve precipitation strengthening effects, but gas elements such as nitrogen are extremely unfavorable to the toughness of steel. While improving the strength and hardness of steel, it also reduces the toughness of steel and increases the brittleness of steel, and too high nitrogen content will lead to loose macroscopic structure or pores. Therefore, the iron element and other specific components are coordinated through a specific ratio relationship, so that the isotropy difference of the steel is small, the structure distribution is more uniform, the performance difference in different places is small, and it has both high strength and good elongation.

[0050] Optionally, the mass percentage of carbon includes: 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0051] The mass percentage of silicon mentioned above includes: 0.1%, 0.13%, 0.14%, 0.15%, 0.18%, 0.2%, 0.25%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0052] The mass percentage of manganese includes: 0.8%, 0.83%, 0.9%, 1%, 1.2%, 1.3%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0053] The mass percentage of vanadium includes: 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0054] The mass percentage of titanium mentioned above includes: 0.1%, 0.13%, 0.14%, 0.15%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0055] The mass percentages of the above-mentioned acid-soluble aluminum include: 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0056] The above-mentioned nitrogen mass percentage includes: 0.001%, 0.002%, 0.0025%, 0.003%, 0.0035%, 0.004%, 0.0045%, 0.005%, 0.0055%, 0.006%, 0.007%, and every value between the minimum and maximum values, or the range consisting of any two values.

[0057] It can be understood that unavoidable impurity elements are impurities that are inevitably introduced into the smelting process due to the limitations of raw materials or process conditions, and their content is at a level that is well known in the art and does not affect the properties of the alloy.

[0058] In some of the embodiments, the microstructure of the high strength steel includes ferrite, martensite, austenite and cementite microstructures.

[0059] In some of the embodiments, the high strength steel has a thickness of 1.2 mm to 2 mm.

[0060] Another aspect of the present invention provides a method for preparing high-strength steel, comprising the following steps S10 to S30.

[0061] S10. Providing raw materials according to the stoichiometric ratio of the components of the high-strength steel, and subjecting the raw materials to smelting and refining treatments in sequence to prepare an alloy melt.

[0062] It should be noted that the raw materials can be adjusted according to the composition of high-strength steel. The ratio of each element in the raw materials can meet the composition of high-strength steel. There is no special requirement for the specific type. It can be a metal element or an alloy.

[0063] In some embodiments, before the refining step, the following step S11 is further included:

[0064] S11: subjecting the alloy melt prepared by the smelting treatment to argon blowing treatment in a ladle.

[0065] In some of the embodiments, during the ladle argon blowing process, the temperature at the end of the argon station is controlled to be greater than 1542°C.

[0066] In some embodiments, the refining treatment is carried out at a temperature of 1570° C. to 1590° C. and for a time of 40 minutes to 120 minutes.

[0067] Specifically, the refining process adopts LF refining (ladle refining furnace): the LF outlet temperature is controlled to be 1570℃~1590℃.

[0068] After the refining treatment, the process also includes a step of deep desulfurizing the refined molten steel in a LF furnace.

[0069] S20, subjecting the alloy melt to casting treatment, hot rolling treatment, cold rolling treatment and annealing treatment in sequence to obtain high-strength steel.

[0070] In some of the embodiments, the casting process adopts a continuous casting process: the continuous casting speed is controlled at ≥3.8 m / min, and the casting is carried out in a light pressure reduction mode.

[0071] In some embodiments, the hot rolling process comprises the following steps:

[0072] The cast slab is heated to a temperature of not less than 1180°C before rolling: the starting rolling temperature is 1090°C to 1150°C, and the final rolling temperature is 850°C to 900°C; wherein the heating treatment time is not less than 25 minutes.

[0073] In some embodiments, after the hot rolling step and before the cold rolling step, the following step S21 is further included:

[0074] S21: The hot-rolled slab is sequentially subjected to laminar cooling and pickling treatment. Specifically, the slab is heated and hot-rolled by a 7-stand finishing mill, then enters a laminar cooling system, and then is pickled.

[0075] In some embodiments, the final cooling temperature of the laminar cooling is 590°C to 640°C.

[0076] In some of the embodiments, the pickling speed is 30 m / min to 120 m / min to ensure that the surface is pickled cleanly.

[0077] In some of the embodiments, the cold rolling treatment conditions include: controlling the single-pass reduction rate of a single stand to be ≥15%, 3 to 5 reciprocating rolling passes, and a rolling speed of 200 m / min to 350 m / min.

[0078] In some embodiments, the annealing conditions include: using a bell-type annealing furnace to perform a hydrogen blowing system, and keeping the temperatures at 400° C., 520° C., and 600° C. for 2 hours, 2 hours, and 10 hours, respectively.

[0079] In some embodiments, after the annealing step, the following steps are further included:

[0080] The annealed slab is flattened.

[0081] In some of the embodiments, during the skin leveling process, the rolling force is controlled to be 300±100 tons.

[0082] By controlling the rolling force of the flattening process, the plate shape is ensured to be strict.

[0083] In some of the embodiments, after the flattening step, the steel is promptly re-rolled and oiled to prevent rusting of the steel.

[0084] In the above preparation method, by further controlling the conditions of each rolling step, each specific component completes hardening measures such as solid solution strengthening, precipitation strengthening, dislocation strengthening, and fine grain strengthening. The grains of appropriate size are obtained by high-temperature deformation recrystallization of the austenite zone, deformation of the low-temperature austenite non-recrystallization zone, and laminar cooling after rolling. Annealing obtains a stable and uniform strengthened structure, thereby further improving the performance of the steel.

[0085] One embodiment of the present invention further provides the use of the above-mentioned high-strength steel or the high-strength steel produced by the above-mentioned method for producing high-strength steel in the production of automobile parts.

[0086] Another embodiment of the present invention further provides a slide rail for automobiles, wherein the slide rail for automobiles comprises the above-mentioned high-strength steel or the high-strength steel produced by the above-mentioned method for producing the high-strength steel.

[0087] The above steel has small isotropy difference, more uniform tissue distribution, small performance difference in different places, high strength and good elongation. The thickness tolerance when made into steel plate is small and the control accuracy is high. When the target thickness is ≤2mm, the thickness accuracy can reach ±20μm.

[0088] The present invention will be described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. It should be understood that the attached claims summarize the scope of the present invention. Under the guidance of the concept of the present invention, those skilled in the art should realize that certain changes made to the various embodiments of the present invention will be covered by the spirit and scope of the claims of the present invention.

[0089] Specific embodiments The following are specific embodiments.

[0090] Example 1

[0091] (1) The mass percentage of each element in high-strength steel is shown in Table 1, and the corresponding preparation raw materials are provided.

[0092] (2) The raw materials are melted into molten iron, which is smelted in a 100-ton converter and then blown with argon in a ladle. During the argon blowing step, the temperature at the end of the argon station is controlled to be greater than 1542°C. The molten iron is then transferred to an LF furnace for refining at a temperature of 1570°C to 1590°C for 40 minutes. The molten steel is deep desulfurized in the LF furnace and then continuously cast. The continuous casting speed is controlled at 3.8 m / min. The casting is made in a light reduction mode to obtain a 70 mm thick slab.

[0093] (3) The slab was heated to 1192°C, heated in the furnace for 31 min, and then thermomechanically controlled rolling was performed by a 7-stand continuous rolling mill: the starting rolling temperature was 1134°C, and the steel strip was cooled by ACC controlled cooling after rolling. The coiling temperature was 606°C, and the thickness specification of the hot-rolled coil was 2.028 mm; then the hot-rolled steel coil was uncoiled and pickled at a speed of 86 m / min, with the acid concentrations of 62 g / L, 112 g / L, and 161 g / L respectively: then a single stand was used for cold rolling: after 3 passes, a 1.68 mm steel coil was formed, and then annealing was performed: a hood annealing furnace was used to implement a hydrogen blowing system, and the temperatures were kept at 400°C, 520°C, and 600°C for 2 hours, 2 hours, and 10 hours, respectively. After cooling, the furnace temperature was 82°C, and finally a flattening treatment was performed using a flattening rolling force of 312 tons to obtain a high-strength steel coil.

[0094] (4) The high-strength steel coils prepared in the above steps were sampled, and the surface layer, the cross section at 1 / 4 thickness, and the cross section at 1 / 2 thickness of the high-strength steel coils were placed under an electron microscope to observe the metallographic structure, as shown in the figure. Figures 1 to 3 As shown in the figure, it can be seen that the structure of the steel is uniform and consistent everywhere.

[0095] (5) The positions of the head, middle and tail of the high-strength steel coil prepared in the above steps are sampled respectively: the head longitudinal, head transverse, tail longitudinal, tail transverse, middle longitudinal and middle transverse are sampled and numbered, and the mechanical properties are tested respectively using industry standard tests. The results are shown in Table 2.

[0096] The test results show that the steel produced by the above steps has high strength and good elongation, as well as good performance uniformity. The strength fluctuation at the head, middle and tail is within 25Mpa. The yield strength of the resulting steel plate is above 900Mpa, the tensile strength is also greater than 900Mpa, the elongation is ≥12%, and the yield strength ratio is close to 1.

[0097] Embodiment 2-3

[0098] Examples 2 to 3 are substantially the same as Example 1, except that the mass percentage of each element in the high-strength steel in step (1) is different from that in Example 1. For details, please see Table 1.

[0099] The remaining steps and conditions are the same as those in Example 1. The mechanical property test results of Examples 2 to 3 are shown in Table 3 and Table 4, respectively.

[0100] The compositions of the high strength steels of Examples 1 to 3 are shown in Table 1.

[0101] Table 1

[0102] content(%) C Si Mn P S Als V Ti N Fe Example 1 0.055 0.16 1.04 0.012 0.0026 0.029 0.022 0.119 0.0035 margin Example 2 0.061 0.17 1.1 0.011 0.003 0.035 0.027 0.13 0.0043 margin Example 3 0.071 0.13 1.11 0.015 0.0021 0.031 0.02 0.114 0.0045 margin

[0103] The high-strength mechanical property results obtained in Example 1 are specifically shown in Table 2.

[0104] Table 2

[0105]

[0106] The high-strength mechanical property results obtained in Example 2 are specifically shown in Table 3.

[0107] Table 3

[0108]

[0109] The high-strength mechanical property results obtained in Example 3 are specifically shown in Table 4.

[0110] Table 4

[0111]

[0112] It can be seen from the data in Tables 2 to 4 that the high-strength steel material of the present application has small isotropy differences, more uniform microstructure distribution, small performance differences at different locations, and has both high strength and good elongation.

[0113] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A high strength steel, characterized in that: The components of the high-strength steel include, in percentage by mass, 0.04% to 0.1% carbon, 0.1% to 0.25% silicon, 0.8% to 1.3% manganese, 0 to 0.005% sulfur, 0 to 0.02% phosphorus, 0.01% to 0.035% vanadium, 0.1% to 0.15% titanium, 0.02% to 0.06% acid-soluble aluminum, 0 < nitrogen ≤ 0.007%, the remainder Fe and unavoidable impurity elements.

2. The high-strength steel according to claim 1, characterized in that The microstructure of the high-strength steel includes ferrite, martensite, austenite and cementite.

3. The high-strength steel according to any one of claims 1 to 2, characterized in that: The thickness of the high-strength steel is 1.2 mm to 2 mm.

4. A method for preparing high-strength steel, characterized in that: The steps include: Providing raw materials according to the stoichiometric ratio of the components of the high-strength steel according to any one of claims 1 to 3, and subjecting the raw materials to smelting and refining treatments in sequence to prepare an alloy melt; The alloy melt is sequentially subjected to casting treatment, hot rolling treatment, cold rolling treatment and annealing treatment to obtain high-strength steel.

5. The method for preparing high-strength steel according to claim 4, characterized in that: Before the refining step, the method further comprises the following steps: subjecting the alloy melt prepared through the smelting treatment to a ladle argon blowing treatment; In the step of argon blowing treatment of the ladle, the temperature at the end of the argon station is controlled to be greater than 1542°C; and / or The refining treatment is performed at a temperature of 1570° C. to 1590° C. and for a time of 40 minutes to 120 minutes.

6. The method for preparing high-strength steel according to claim 4, characterized in that: The hot rolling process comprises the following steps: The cast slab is heated and then rolled: the starting rolling temperature is 1090°C to 1150°C, and the final rolling temperature is 850°C to 900°C; wherein the heating treatment time is not less than 25 minutes.

7. The method for preparing high-strength steel according to any one of claims 4 to 6, characterized in that: The cold rolling treatment conditions include: controlling the single-pass reduction rate of a single stand to be ≥15%, 3 to 5 reciprocating rolling passes, and a rolling speed of 200 m / min to 350 m / min; and / or The annealing treatment conditions include: using a bell-type annealing furnace to perform a hydrogen blowing system, and keeping the temperatures at 400° C., 520° C., and 600° C. for 2 hours, 2 hours, and 10 hours, respectively.

8. The method for preparing high-strength steel according to any one of claims 4 to 6, characterized in that: After the hot rolling step and before the cold rolling step, the method further includes the following steps: The slab after the hot rolling treatment is sequentially subjected to laminar cooling and pickling treatment; wherein the final cooling temperature of the laminar cooling is 590° C. to 640° C., and the speed of the pickling treatment is 30 m / min to 120 m / min; and / or After the annealing step, the method further comprises the following steps: The slab that has undergone the annealing treatment is flattened; wherein, during the flattening treatment, the rolling force is controlled to be 300±100 tons.

9. Use of the high-strength steel according to any one of claims 1 to 3 or the high-strength steel produced by the method for producing high-strength steel according to any one of claims 4 to 8 in automobile parts.

10. A slide rail for an automobile, characterized in that: The automobile slide rail comprises the high-strength steel according to any one of claims 1 to 3 or the high-strength steel produced by the method for producing high-strength steel according to any one of claims 4 to 8.

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