Weathering steel, preparation method thereof and engineering mechanical equipment

Abstract

The invention relates to weathering steel, a preparation method of the weathering steel and engineering mechanical equipment. The weathering steel comprises the following components: 0.15%-0.18% of carbon, 0.3%-0.5% of silicon, 1.5%-1.8% of manganese, 0.04%-0.055% of niobium, 0.035%-0.055% of titanium, 0.45%-0.8% of chromium, 0.3%-0.5% of nickel, 0.3%-0.35% of copper, 0.2%-0.25% of molybdenum, 0.015%-0.035% of acid-soluble aluminum, more than 0 and less than or equal to 0.0005% of boron, more than 0 and less than or equal to 0.0006% of nitrogen, less than or equal to 0.00015% of oxygen, less than or equal to 0.0015% of hydrogen, less than or equal to 0.015% of sulfur, less than or equal to 0.018% of phosphorus and the balance of Fe and inevitable impurity elements. The steel has high strength, good ductility and excellent low-temperature weather resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and in particular to weathering steel and a preparation method thereof, and engineering machinery and equipment. Background Art

[0002] In order to adapt to the difficulty of construction, engineering machinery and equipment are generally required to have good mechanical properties, such as high tensile strength, elongation and impact strength. As the construction environment becomes increasingly complex, higher requirements are also placed on the weather resistance of engineering machinery and equipment. For example, engineering machinery and equipment are required to have low-temperature weather resistance in complex climatic environments, and maintain good mechanical properties at low temperatures. However, how to obtain steel that has both good mechanical properties and low-temperature weather resistance 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 weathering steel having high strength, good elongation and excellent low-temperature weathering resistance, a preparation method thereof, and engineering machinery equipment.

[0005] One aspect of the present invention provides a weathering steel, wherein the components of the weathering steel include, in percentage by mass: 0.15%-0.18% carbon, 0.3%-0.5% silicon, 1.5%-1.8% manganese, 0.04%-0.055% niobium, 0.035%-0.055% titanium, 0.45%-0.8% chromium, 0.3%-0.5% nickel, 0.3%-0.35% copper, 0.2%-0.25% molybdenum, 0.015%-0.035% acid-soluble aluminum, 0<boron≤0.0005%, 0<nitrogen≤0.0006%, oxygen≤0.00015%, hydrogen≤0.0015%, sulfur≤0.015%, phosphorus≤0.018%, and the remainder Fe and unavoidable impurity elements.

[0006] The yield strength Rel of the weathering steel is 720MPa-750MPa, the tensile strength Rm is 830MPa-880MPa, the yield strength ratio Rel / Rm≤0.9, the elongation is greater than 12%, the -40℃ KV2 impact power is greater than 60J, and the relative corrosion rate of the 0.01mol / L sodium bisulfate cycle immersion test for 144 hours is 0.015g / (m 2 ).

[0007] In some of the embodiments, the structure of the weathering steel includes tempered martensite and austenite.

[0008] In some of the embodiments, the thickness of the weathering steel is 4 mm to 25.5 mm.

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

[0010] Providing raw materials according to the stoichiometric ratio of the components of the weathering 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, rolling treatment and quenching and tempering heat treatment to obtain weathering steel.

[0012] In the preparation method of the above-mentioned weathering steel, the raw materials for preparation conforming to the stoichiometric ratio of the above-mentioned weathering steel are smelted and refined into an alloy melt, and then after the casting process, rolling treatment and tempering heat treatment are carried out in sequence to obtain grains of suitable size by deformation recrystallization of the austenite zone and deformation of the austenite non-recrystallization zone. At the same time, the volume fractions of martensite and austenite are adjusted, and the grains are divided into several small spaces to achieve the purpose of toughening the matrix. A large amount of NbC and Cu-rich strengthening phases are precipitated between the matrix to ensure high strength performance, so that the steel can have high strength, good elongation and excellent low-temperature weathering resistance.

[0013] In some embodiments, the rolling process comprises the following steps:

[0014] The ingot after the casting treatment is heated to 1220°C-1260°C, and then rough rolling, finish rolling and laminar flow cooling treatment are carried out in sequence. The starting rolling temperature of the rough rolling is 1150°C-1180°C, and the final rolling temperature is 1080°C-1000°C. The starting rolling temperature of the finish rolling is 1060°C-980°C, and the final rolling temperature is 880°C-840°C. The cooling rate of the flow cooling treatment is 20°C / s-30°C / s, and the final cooling temperature is 610°C-570°C.

[0015] In some embodiments, after the step of casting and before the step of rolling, the following steps are further included:

[0016] Cooling the ingot after the casting process to room temperature; and / or

[0017] The rough rolling includes 5 rolling passes, and the finish rolling includes 7 rolling passes.

[0018] In some embodiments, the quenching and tempering heat treatment comprises the following steps:

[0019] The slab after the rolling treatment is solution treated at 950°C for 30 minutes, then water quenched, and then tempered at 650°C.

[0020] In some embodiments, before the refining step, the following steps are also included:

[0021] subjecting the alloy melt that has undergone the smelting treatment to a ladle argon blowing treatment;

[0022] 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 1535°C.

[0023] In some embodiments, the refining treatment conditions include: an inlet temperature greater than 1522° C., an outlet temperature of 1585° C.-1620° C., and a refining time of 40 minutes-45 minutes; and / or

[0024] After the refining step and before the casting step, the following steps are also included:

[0025] The molten iron after the refining treatment is subjected to a steel liquid vacuum circulation treatment at a temperature greater than 1538° C. The vacuum degree of the steel liquid vacuum circulation treatment is ≤67MPa, and the circulation time is 22min-30min.

[0026] According to another aspect of the present invention, there is provided an engineering machinery equipment, which comprises the above-mentioned weathering steel or the weathering steel produced by the above-mentioned method for producing weathering steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the metallographic structure diagram of the weathering steel coil prepared in Example 1;

[0028] Figure 2 This is the metallographic structure diagram of the weathering steel coil prepared in Example 2. DETAILED DESCRIPTION

[0029] 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.

[0030] 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.

[0031] the term

[0032] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0033] The terms "and / or", "or / and", and "and / or" used in this article have a selection range that includes any one of two or more related listed items, and also includes 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").

[0034] 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".

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] An embodiment of the present invention provides a weathering steel, which comprises, by mass percentage, 0.15%-0.18% carbon, 0.3%-0.50% silicon, 1.5%-1.8% manganese, 0.04%-0.055% niobium, 0.035%-0.055% titanium, 0.45%-0.8% chromium, 0.3%-0.5% nickel, 0.3%-0.35% copper, 0.2%-0.25% molybdenum, 0.015%-0.035% acid-soluble aluminum, 0<boron≤0.0005%, 0<nitrogen≤0.0006%, oxygen≤0.00015%, hydrogen≤0.0015%, sulfur≤0.015%, phosphorus≤0.018%, and the remainder Fe and unavoidable impurity elements.

[0044] The above-mentioned weathering steel contains components in specific proportions, among which: carbon is an effective element to improve the mechanical properties of steel. When the carbon content is high, although lath martensite will be formed to ensure strength performance, too high a carbon content will reduce low-temperature toughness, deteriorate welding performance and reduce corrosion resistance; silicon can be deoxidized during the smelting process, but its excessive content will have an adverse effect on toughness; manganese is beneficial to the refinement of martensite laths, and can achieve a two-way improvement in strength and toughness; sulfur is a harmful element in high-strength steel and is prone to produce MnS, which is harmful to impact toughness, corrosion resistance and welding performance, so the sulfur content needs to be controlled; excessive phosphorus will produce grain boundary segregation and increase the brittleness of steel, while an appropriate amount of phosphorus can improve the weathering resistance of steel; niobium is a carbide-forming element that can increase the recrystallization temperature of austenite, and austenite can be rolled at a higher rolling temperature. In addition, Nb can precipitate and strengthen during rolling and cooling. The strain-induced precipitation of Nb carbonitrides can pin austenite grains, refine austenite grains and improve strength and low-temperature toughness. However, too high Nb makes it difficult to control the yield ratio, and too low Nb content has no obvious grain refinement effect. Titanium can combine with nitrogen to form TiN during casting solidification, reducing the effect of nitrogen on boron, and the presence of TiN can inhibit the coarsening of grains in the heat-affected zone of welding. Aluminum and an appropriate amount of boron are beneficial to the formation of acicular ferrite, but too much aluminum will damage the toughness of steel. An appropriate amount of chromium can improve corrosion resistance, while It can enhance the liquid permeability of steel, promote the formation of needle-plate martensite, and improve strength performance; copper can increase corrosion resistance, improve the hardenability of steel, and significantly improve the core strength and thickness uniformity of steel plate; appropriate amount of nickel can enhance the hardenability of steel matrix, reduce the network cracking caused by copper embrittlement of copper-containing steel, and significantly improve low-temperature toughness; molybdenum can improve the thermal stability of microalloy carbonitrides, reduce the deformation of steel plate caused by uneven heating during flame cutting and welding, and ensure the accuracy of components, while oxygen, hydrogen and other gas elements are extremely unfavorable to the toughness of steel, and their content should be strictly controlled. Therefore, the iron element and other specific components are synergistically used through a specific ratio relationship, so that the steel can have both high strength, good elongation and excellent low-temperature weathering resistance.

[0045] Optionally, the mass percentage of carbon includes: 0.15%, 0.16%, 0.17%, 0.18%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0046] Optionally, the mass percentage of silicon includes: 0.3%, 0.4%, 0.5%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0047] Optionally, the mass percentage of manganese includes: 1.8%, 1.7%, 1.6%, 1.5%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0048] Optionally, the mass percentage of niobium includes: 0.04%, 0.045%, 0.05%, 0.055%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0049] Optionally, the mass percentage of titanium includes: 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0050] Optionally, the mass percentage of chromium includes: 0.45%, 0.5%, 0.6%, 0.7%, 0.8%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0051] Optionally, the mass percentage of nickel includes: 0.5%, 0.4%, 0.35%, 0.3%, and each value between the minimum and maximum values, or a range consisting of any two values.

[0052] Optionally, the mass percentage of copper includes: 0.34%, 0.35%, 0.3%, and any value between the minimum and maximum values, or a range consisting of any two values.

[0053] Optionally, the mass percentage of molybdenum includes: 0.24%, 0.25%, 0.2%, and each value between such minimum and maximum values, or a range consisting of any two values.

[0054] Optionally, the mass percentage of the acid-soluble aluminum includes: 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.

[0055] Optionally, the mass percentage of nitrogen includes: 0.0001%, 0.0002%, 0.00025%, 0.0003%, 0.00035%, 0.0004%, 0.00045%, 0.0005%, 0.00055%, 0.0006%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0056] Optionally, the mass percentage of boron includes: 0.0001%, 0.0002%, 0.00025%, 0.0003%, 0.00035%, 0.0004%, 0.00045%, 0.0005%, and every value between the minimum and maximum values, or a range consisting of any two values.

[0057] Optionally, 0≤oxygen≤0.00015%, 0≤hydrogen≤0.0015%, 0≤sulfur≤0.015%, 0≤phosphorus≤0.018%.

[0058] 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.

[0059] In some of these embodiments, the structure of the weathering steel includes tempered martensite and austenite.

[0060] In some of the embodiments, the thickness of the weathering steel is 4 mm to 25.5 mm.

[0061] Another aspect of the present invention provides a method for preparing weathering steel, comprising the following steps S10 to S20.

[0062] S10. Providing raw materials according to the stoichiometric ratio of the components of the weathering steel, and subjecting the raw materials to smelting and refining treatments in sequence to prepare an alloy melt.

[0063] It should be noted that the raw materials can be adjusted according to the composition of weathering steel. The ratio of each element in the raw materials can meet the composition of weathering steel. There is no special requirement for the specific type. It can be a metal element or an alloy.

[0064] In some embodiments, before the refining step, the following step S11 is further included:

[0065] S11: subjecting the smelted alloy melt to argon blowing in a ladle.

[0066] 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 1535°C.

[0067] In some of the embodiments, before the smelting step, the molten iron used to prepare the raw material is subjected to KR desulfurization: the sulfur content is removed to below 0.010%, and the molten iron can enter the furnace for converter smelting.

[0068] In some of the embodiments, the refining conditions include: an inlet temperature greater than 1522° C., an outlet temperature of 1585-1620° C., and a refining time of 40 minutes to 45 minutes.

[0069] Specifically, the refining process adopts LF refining (ladle refining furnace).

[0070] S20, subjecting the alloy melt to casting treatment, rolling treatment and quenching and tempering heat treatment in sequence to obtain weathering steel.

[0071] In the preparation method of the above-mentioned weathering steel, the raw materials for preparation conforming to the stoichiometric ratio of the above-mentioned weathering steel are smelted and refined into an alloy melt, and then after the casting process, rolling treatment and tempering heat treatment are carried out in sequence to obtain grains of suitable size by deformation recrystallization of the austenite zone and deformation of the austenite non-recrystallization zone. At the same time, the volume fractions of martensite and austenite are adjusted, and the grains are divided into several small spaces to achieve the purpose of toughening the matrix. A large amount of NbC and Cu-rich strengthening phases are precipitated between the matrix to ensure high strength performance, so that the steel can have high strength, good elongation and excellent low-temperature weathering resistance.

[0072] In some embodiments, after the refining step and before the casting step, the following steps are further included:

[0073] The molten iron after the refining treatment is subjected to a steel liquid vacuum circulation treatment at a temperature greater than 1538°C. The vacuum degree of the steel liquid vacuum circulation treatment is ≤67MPa, and the circulation time is 22min-30min.

[0074] In some of the embodiments, the continuous casting process adopts continuous casting, the casting speed is controlled at 0.9-1.1 m / min, and the casting billet adopts a light pressure reduction mode.

[0075] In some embodiments, the rolling process includes the following steps:

[0076] The ingot after casting is heated to 1220°C-1260°C, and then subjected to rough rolling, finish rolling and laminar flow cooling in sequence. The starting rolling temperature of the rough rolling is 1150°C-1180°C, the final rolling temperature is 1080°C-1000°C, the starting rolling temperature of the finish rolling is 1060°C-980°C, the final rolling is 880°C-840°C, the cooling rate of the laminar flow cooling is 20°C / s-30°C / s, and the final cooling temperature is 610°C-570°C.

[0077] In some embodiments, the heating treatment time is 150 min-250 min.

[0078] In some embodiments, the rough rolling includes 5 rolling passes, and the finish rolling includes 7 rolling passes.

[0079] Specifically, the rolling process is performed using a single stand.

[0080] In some embodiments, after the step of casting and before the step of rolling, the following steps are further included:

[0081] S21: Cooling the ingot after the casting process to room temperature.

[0082] In some embodiments, the tempering heat treatment comprises the following steps:

[0083] The slab after rolling was solution treated at 950°C for 30 minutes, then water quenched and tempered at 650°C.

[0084] In the above preparation method, by further controlling the rolling steps and the conditions of the quenching and tempering heat treatment, the continuous rolling and heat treatment conditions are fully utilized, and the grains of suitable size are obtained through deformation recrystallization of the high-temperature austenite zone, deformation of the low-temperature austenite non-recrystallization zone, and accelerated cooling after rolling. The quenching and tempering heat treatment process adopts a quenching + tempering quenching and tempering process, and the austenitization of the structure is ensured under solid solution. Water quenching is adopted to obtain a full martensitic structure, and then high-temperature tempering is performed. The quenched martensitic matrix is ​​decomposed into a reverse-transformed austenitic structure to regulate the volume fraction of the austenitic structure.

[0085] Another embodiment of the present invention further provides an engineering machinery equipment, which includes the above-mentioned weathering steel or the weathering steel produced by the above-mentioned weathering steel preparation method.

[0086] The above-mentioned steel has high strength, good elongation and excellent low-temperature weather resistance. It can still maintain good mechanical properties under low temperature or acidic conditions and can better adapt to various complex construction environments.

[0087] 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.

[0088] Specific embodiments The following are specific embodiments.

[0089] Example 1

[0090] (1) The mass percentage of each element in weathering steel is shown in Table 1, and the corresponding preparation raw materials are provided.

[0091] (2) The raw materials are melted into molten iron. The molten iron is desulfurized by KR and then smelted in a 210-ton converter. Then, argon is blown into a ladle. During the argon blowing treatment step, the temperature at the end of the argon station is controlled to be greater than 1542°C. Then, the molten iron is transferred to the LF furnace for refining: the inlet temperature is greater than 1522°C, the LF outlet temperature is 1585°C-1620°C, and the refining time is 40 minutes. When the molten steel temperature is greater than 1538°C, the molten iron is transferred to the RH for vacuum treatment: the vacuum degree is required to be ≤67MPa, and the RH cycle time is 22min. Then, continuous casting is continued. The continuous casting pulling speed is controlled at 1m / min. The ingot is cast in a light pressure mode to obtain an ingot with a thickness of 230mm.

[0092] (3) The ingot was pile-cooled for 48 h to room temperature, and then heated to 1232° C. The heating time in the furnace was 150 min. The furnace temperature was shown in Table 2. The ingot was then subjected to 5 rough rolling passes in a single stand, and then subjected to 7 rough rolling passes in a rough rolling unit. After rolling, the ingot was subjected to a laminar cooling system for organizational control. The starting rolling temperature and the final rolling temperature of the rough rolling, the starting rolling temperature and the final rolling temperature of the finishing rolling, the cooling rate of the laminar cooling treatment, and the final cooling curling temperature were shown in Table 2. The weathering steel coil was obtained, and the thickness was shown in Table 2.

[0093] (4) Samples of the weathering steel coils obtained in the above steps are placed under an electron microscope to observe the metallographic structure. Figure 1 As shown, the structure of the steel can be seen in various parts.

[0094] (5) The mechanical properties of the weathering steel coil prepared in the above steps were tested according to industry standards, and the results are shown in Table 3. Wherein, Rel is the yield strength, Rm is the tensile strength, and A is the elongation.

[0095] (6) The weathering steel coil prepared in the above steps was heated to 0.01 mol / L NaHSO 3 The immersion test was carried out in an acidic environment with a pH of 4-5. The 144-hour weight loss rate and 144-hour relative corrosion rate are shown in Table 4.

[0096] Embodiment 2-3

[0097] Examples 2 to 3 are basically the same as Example 1, except that the thickness of the weathering steel coil in step (3) is different from that in Example 1. For details, please see Table 2.

[0098] The remaining steps and conditions are the same as those in Example 1. The metallographic structure of the weathering steel obtained in Example 2 is as follows: Figure 2 shown.

[0099] The compositions of the weathering steels of Examples 1 to 3 are shown in Table 1.

[0100] Table 1

[0101]

[0102] The process conditions of the rolling treatment and the thickness of the weathering steel coil in Examples 1 to 3 are shown in Table 2.

[0103] Table 2

[0104]

[0105] The mechanical properties of the weathering steels obtained in Examples 1 to 3 are specifically shown in Table 3.

[0106] Table 3

[0107]

[0108] The weathering performance results of the weathering steels obtained in Examples 1 to 3 are specifically shown in Table 4.

[0109] Table 4

[0110] serial number <![CDATA[144 - hour weightlessness (g·m -2 )]]> 144 hours relative corrosion rate Example 1 0.253 38.6％ Example 2 0.258 39.2％ Example 3 3.92 100％

[0111] It can be seen from the data in Tables 1 to 4 that the weathering steel material of the present application has high strength, good elongation and excellent low-temperature weathering resistance, can maintain good mechanical properties under low temperature or acidic conditions, and can better adapt to various complex construction environments.

[0112] 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.

[0113] 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 weathering steel, characterized in that: The components of the weathering steel include, in percentage by mass, 0.15%-0.18% carbon, 0.3%-0.50% silicon, 1.5%-1.8% manganese, 0.04%-0.055% niobium, 0.035%-0.055% titanium, 0.45%-0.8% chromium, 0.3%-0.5% nickel, 0.3%-0.35% copper, 0.2%-0.25% molybdenum, 0.015%-0.035% acid-soluble aluminum, 0<boron≤0.0005%, 0<nitrogen≤0.0006%, oxygen≤0.00015%, hydrogen≤0.0015%, sulfur≤0.015%, phosphorus≤0.018%, and the remainder Fe and unavoidable impurity elements.

2. The weathering steel according to claim 1, characterized in that: The structure of the weathering steel includes tempered martensite and austenite.

3. The weathering steel according to any one of claims 1 to 2, characterized in that: The thickness of the weathering steel is 4 mm to 25.5 mm.

4. A method for preparing weathering steel, characterized in that: The steps include: Providing raw materials according to the stoichiometric ratio of the components of the weathering 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, rolling treatment and quenching and tempering heat treatment to obtain weathering steel.

5. The method for preparing weathering steel according to claim 4, characterized in that: The rolling process comprises the following steps: The ingot after the casting treatment is heated to 1220°C-1260°C, and then rough rolling, finish rolling and laminar flow cooling treatment are carried out in sequence. The starting rolling temperature of the rough rolling is 1150°C-1180°C, and the final rolling temperature is 1080°C-1000°C. The starting rolling temperature of the finish rolling is 1060°C-980°C, and the final rolling temperature is 880°C-840°C. The cooling rate of the flow cooling treatment is 20°C / s-30°C / s, and the final cooling temperature is 610°C-570°C.

6. The method for preparing weathering steel according to claim 5, characterized in that: After the step of casting and before the step of rolling, the method further includes the following steps: Cooling the ingot after the casting process to room temperature; and / or The rough rolling includes 5 rolling passes, and the finish rolling includes 7 rolling passes.

7. The method for preparing weathering steel according to any one of claims 4 to 6, characterized in that: The quenching and tempering heat treatment comprises the following steps: The slab after the rolling treatment is solution treated at 950°C for 30 minutes, then water quenched, and then tempered at 650°C.

8. The method for preparing weathering steel according to any one of claims 4 to 6, characterized in that: Before the refining step, the method further comprises the following steps: subjecting the alloy melt that has undergone 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 1535°C.

9. The method for preparing weathering steel according to any one of claims 4 to 6, characterized in that: The refining treatment conditions include: inlet temperature greater than 1522°C, outlet temperature of 1585°C-1620°C, refining time of 40 minutes-45 minutes; and / or After the refining step and before the casting step, the following steps are also included: The molten iron after the refining treatment is subjected to a steel liquid vacuum circulation treatment at a temperature greater than 1538° C. The vacuum degree of the steel liquid vacuum circulation treatment is ≤67MPa, and the circulation time is 22min-30min.

10. An engineering machinery equipment, characterized in that: The engineering machinery equipment comprises the weathering steel as described in any one of claims 1 to 3 or the weathering steel produced by the method for producing weathering steel as described in any one of claims 4 to 8.

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