A HB450 grade wear-resistant and corrosion-resistant steel plate and its production method

Abstract

The present invention relates to an HB450 grade wear-resistant and corrosion-resistant steel plate and a production method thereof. The chemical composition of the steel plate is as follows by weight: C: 0.20% to 0.23%, Si: 0.2% to 0.4%, Mn: 0.2% to 0.4%, Nb: 0.10% to 0.20%, Cr: 3.10% to 3.30%, Al: 0.31% to 0.4%, Ni: 1.0% to 1.5%, 1.4%≤Al+Ni≤1.8%, and the balance is Fe and unavoidable impurities; impurity elements in the steel are controlled as follows: P≤0.012%, S≤0.00 2%, [N]≤0.0040%, [H]≤0.00015%, [O]≤0.0010%, and retained austenite content of 5% to 8%; the present invention utilizes Nb to precipitate high-hardness particles to enhance the wear resistance of the steel plate, and utilizes Cr to increase the natural corrosion potential of the steel plate, thereby inhibiting corrosion by fluids such as seawater; adopts smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment processes to produce a wear-resistant and corrosion-resistant steel plate with a Brinell hardness of 450HB, which has wear resistance and corrosion resistance that is more than 1.2 times that of ordinary low-alloy wear-resistant steel plates with the same hardness.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to an HB450 grade wear-resistant and corrosion-resistant steel plate and a production method thereof. Background Art

[0002] Wear-resistant and corrosion-resistant steel is mainly used to manufacture certain moving parts of mechanical equipment working in corrosive and wear environments, such as pipelines, impellers, valves of corrosive flowing media in offshore dredging projects, urban garbage truck bodies, corrosive liquid agitators of chemical equipment, etc. The surface of the material is not only corroded by the environmental media but also wears away. In the early days, wear-resistant and corrosion-resistant projects at home and abroad were made of inexpensive Q235B and Q345B ordinary carbon structural steels, which had poor wear and corrosion resistance. Wear-resistant equipment made of stainless steel has good corrosion resistance but is expensive and not wear-resistant.

[0003] In recent years, some dredging companies have used ordinary low-alloy martensitic wear-resistant steel plates for the production of wear-resistant and corrosion-resistant structures. Although they have good wear resistance, they are not corrosion-resistant. Under the combined effects of complex environments such as seawater corrosion and coarse sand wear, they wear quickly and crack at a high rate, making it difficult to promote and apply them on a large scale. Therefore, it is urgent to develop new wear-resistant steel plates that are both wear-resistant and corrosion-resistant to meet the urgent needs of my country's wear-resistant and corrosion-resistant equipment.

[0004] The production of wear-resistant and corrosion-resistant steel plates at home and abroad has formed a number of public prior art patents, such as the following 4 Chinese patents and 1 Japanese patent:

[0005] Chinese Patent 1, Baoshan Iron & Steel Co., Ltd., Wen Donghui; Song Fengming; Yang Ana's invention patent publication number: CN108930001B, "A high-hardness wear-resistant steel plate for slurry dredging and its production method", the invention relates to a high-hardness wear-resistant steel for slurry dredging, the composition weight percentage of which is: C: 0.18-0.24%, Si≤0.01, Mn: 1.3-1.6%, P≤0.015%, S≤0.005%, Al: 0.2-1.0%, Cr: 0.3-1.2%, B: 0.001-0.002%, N≤0.005%; in addition, it contains Nb: 0.01-0.03% or Ti: 0.01-0.025% One or two of them, and satisfy 6.65N<Nb+Ti≤0.045, and the rest are Fe and unavoidable impurity elements; the wear-resistant steel has a yield strength of more than 1100MPa, a tensile strength of more than 1300MPa, an elongation ≥10%, a hardness of 450±30HBW, and an impact energy value of more than 20J at -40℃; the composition design of the wear-resistant steel of this invention takes into account both corrosion resistance and wear resistance, and is mainly used for the production of dredging pipelines in the fields of land reclamation and channel dredging. Its wear resistance is twice that of the current ordinary pipes, thereby greatly improving dredging efficiency and reducing operating costs. However, this invention is an ordinary martensitic wear-resistant steel, the steel plate has low plasticity, and the internal stress after forming is large, which is prone to stress corrosion cracking.

[0006] China Patent 2, Guangdong Shaoguan Iron & Steel Songshan Co., Ltd., Pan Hui, Liu Kun, Guo Huimin, et al., invention patent publication number: CN112145815A, "A Corrosion-Resistant Steel Pipe and Its Preparation Method", the invention relates to a corrosion-resistant steel pipe and its preparation method, belonging to the field of marine sand pumping technology. The corrosion-resistant steel pipe includes an inner pipe and an outer pipe, the outer pipe is sleeved and fixed to the inner pipe, the outer pipe is made of low-alloy steel, and the inner pipe is made of alloy mold steel; the mass fraction of C in the alloy mold steel is 0.35% to 0.45%, and the mass fraction of Cr is 0.80% to 2. 10%, the carbon equivalent of the alloy die steel is 0.7% to 1.28%, the outer layer tube can make the corrosion-resistant steel pipe meet the strength and toughness requirements, the inner layer tube is used to directly contact the sand containing seawater, and the contact surface between the inner layer tube and the sand containing seawater has high hardness, wear resistance and resistance to seawater corrosion. This corrosion-resistant steel pipe can be used for marine sand pumping steel pipes to increase the service life of marine sand pumping steel pipes. Calculated based on 12 hours of operation per day, the service life reaches 500 to 833 days. The invention has good wear resistance and corrosion resistance, but requires heterogeneous composite of the inner and outer layers, and the process is complex and not easy to implement.

[0007] Chinese Patent 3, Nanjing Industrial Vocational and Technical College, Shi Yuanji, Yu Linhui applied for invention patent with publication number CN109881122A "High wear-resistant and corrosion-resistant large tillage depth rotary blade material and preparation method thereof", the invention discloses a high wear-resistant and corrosion-resistant large tillage depth rotary blade material and its preparation method, the rotary blade material is based on 60Si2Mn, 50CrVA steel alloy composition, and Nb and Al elements are added, by mass fraction, including: C: 0.30% to 0.45%, Si: 0.20% to 0.60%, Mn: 1.5 0%~2.30%, Cr: 1.50%~3.00%, Ni: 0.10%~0.30%, V: 0.10%~0.30%, Al: 0.10%~0.30%, Nb: 0.01%~0.05%, P<0.035%, S<0.035%, Fe balance. The material of the invention is hard on the surface and tough on the core, and is suitable for preparing long-life and deep-ploughing rotary tiller blades; the rotary tiller blades after surface treatment with composite rare earth boron carbonitriding and optimization of alloy composition have excellent wear resistance. The patent has good abrasion resistance, but the production process is complicated and requires surface heat treatment.

[0008] Chinese Patent 4, Hunan Valin Lianyuan Iron and Steel Co., Ltd., Liang Liang, Wang Hongbing, Wen Changfei, etc. applied for invention patent with publication number CN111575581A "A martensitic wear-resistant steel plate resistant to acid corrosion and its manufacturing method", the invention discloses a martensitic wear-resistant steel plate resistant to acid corrosion, which includes, by mass percentage, 0.14wt%≤C≤0.22wt%; 0.30wt%≤Si≤0.60wt%; 0.30wt%≤Mn≤1.00wt%; 0.010wt%≤Ti≤0.020wt%; 0.02wt%≤Nb≤0.04wt% t%; 0.50wt%≤Ni≤1.0wt%; 0.20wt%≤Cu≤0.50wt%; 0.9wt%≤Cr≤1.3wt%; 0.08wt%≤Sb≤0.12wt%; 0.0010wt%≤B≤0.0020wt%; 0<S≤0.003wt%; 0<P≤0.012wt%; The acid-corrosion-resistant martensitic wear-resistant steel plate can take into account the problems of steel plate hardness, plasticity, toughness, wear resistance and corrosion resistance. This patent requires water-cooling quenching heat treatment, has large internal stress, is prone to cracking and deformation, and is only suitable for acid corrosion.

[0009] Japanese Patent 1, invention patent of JIFI Steel Co., Ltd., Yusuke Terasawa; Naoki Takayama; Kenji Hayashi; Kazukuni Hase, application publication number CN109072367A, "Wear-resistant steel plate and method for manufacturing wear-resistant steel plate", discloses a steel plate having the following composition and structure, the composition is calculated by mass percentage: C: 0.10% to 0.23%, Si: 0.01% to 1.0%, Mn: 0.30% to 3.00%, P: less than 0.025%, S: less than 0.02% The invention relates to a wear-resistant steel plate comprising 0.01% to 2.00% Cr, 0.001% to 0.100% Al, and less than 0.01% N, with the remainder being Fe and unavoidable impurities, wherein the volume fraction of martensite at a depth of 1 mm from the surface of the wear-resistant steel plate is 90% or more, the original austenite grain size at the center of the plate thickness of the wear-resistant steel plate is less than 80 μm, and the hardness at a depth of 1 mm from the surface of the wear-resistant steel plate is 360 to 490 HBW in terms of Brinell hardness. 10 / 3000 wear-resistant steel plate and method for manufacturing wear-resistant steel plate, but the steel plate has a complex alloy composition, high cost, and only ordinary wear resistance.

[0010] It can be seen that the existing patents for wear-resistant and corrosion-resistant steel plates have the following deficiencies:

[0011] 1. Requires heterogeneous composite or surface heat treatment;

[0012] 2. Low plasticity and toughness;

[0013] 3. The internal stress is large after water quenching;

[0014] 4. Poor corrosion resistance and wear resistance. Summary of the Invention

[0015] The present invention provides an HB450 grade wear-resistant and corrosion-resistant steel plate and a production method thereof. The new wear-resistant and corrosion-resistant concept is adopted, and the wear resistance of the steel plate is enhanced by precipitating high-hardness particles using Nb. The natural corrosion potential of the steel plate is increased by using Cr and Ni, thereby inhibiting corrosion by fluids such as seawater. The austenite phase region is expanded by controlling the Ni content, the amount of retained austenite in the steel is increased, and the toughness and plasticity of the steel are improved. The wear-resistant and corrosion-resistant steel plate with a Brinell hardness of 450HB is produced by adopting a unique smelting, rolling and heat treatment production process. The wear-resistant and corrosion-resistant steel plate has a wear resistance and corrosion resistance that is more than 1.2 times that of ordinary low-alloy wear-resistant steel plates with the same hardness.

[0016] In order to achieve the above object, the present invention adopts the following technical solutions:

[0017] A HB450 grade wear-resistant and corrosion-resistant steel plate, wherein the chemical composition of the steel plate is as follows by weight: C: 0.20% to 0.23%, Si: 0.2% to 0.4%, Mn: 0.2% to 0.4%, Nb: 0.10% to 0.20%, Cr: 3.10% to 3.30%, Al: 0.31% to 0.40%, Ni: 1.0% to 1.5%, 1.4%≤Al+Ni≤1.8%, the balance being Fe and unavoidable impurities; impurity elements in the steel are controlled as follows: P≤0.012%, S≤0.002%, [N]≤0.0040%, [H]≤0.00015%, [O]≤0.0010%, and the retained austenite content is 5% to 8%;

[0018] A method for producing HB450 grade wear-resistant and corrosion-resistant steel plates, comprising the following process steps: smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment; wherein:

[0019] 1) Refining: RH vacuum cycle time ≥ 16 min;

[0020] 2) Continuous casting: The target superheat of the tundish is controlled at ≤25°C, and the casting process is protected. Electromagnetic stirring or soft pressure is used, and intermediate cooling is used in the secondary cooling zone. The continuous casting billet casting speed is controlled at 1.1-1.3m / min.

[0021] 3) Rolling: The temperature of the heating and soaking section is 1200-1280°C, and the soaking time is greater than 2.0 hours. During rolling, two stages of controlled rolling are adopted, namely rough rolling and finishing rolling. The starting rolling temperature of the rough rolling stage is ≥1100°C, and the finishing rolling temperature is controlled at ≥1000°C; the starting rolling temperature of the finishing rolling is 950-1000°C, the finishing rolling reduction ratio is ≥60%, and the finishing rolling temperature is 870-920°C. After rolling, the steel is air-cooled to room temperature.

[0022] 4) Tempering heat treatment: The tempering temperature is 230-260°C, and the tempering holding time is 5-8 min / mm.

[0023] Furthermore, after the continuous casting slab comes off the line, it enters a slow cooling pit for heating and slow cooling. The starting temperature of the slab slow cooling is required to be ≥400°C, and it is heated to 630-650°C at a heating rate of ≤50°C / second. After being kept warm for 8-12 hours, it is slowly cooled to less than 400°C with the furnace and air-cooled to room temperature after being taken out of the furnace.

[0024] Furthermore, the surface hardness of the steel plate is ≥ HB450, the tensile strength is ≥ 1300 MPa, and the corrosion resistance and wear resistance are more than 1.2 times that of ordinary NM450.

[0025] Furthermore, the thickness of the ingot is 200 to 250 mm.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1) Nb is used to precipitate high-hardness particles to increase the wear resistance of the steel plate, refine the grains to improve toughness, and Cr and Ni are used to increase the natural corrosion potential of the steel plate, which inhibits corrosion from fluids such as seawater, thereby reducing the occurrence of corrosion and ensuring the corrosion resistance of the steel. The corrosion resistance and wear resistance of the steel plate are more than 1.2 times that of ordinary NM450;

[0028] 2) The chemical composition of the steel plate of the present invention is mainly characterized by microalloying of chromium, nickel, and niobium. The alloy content is relatively low, which facilitates smelting and continuous casting. The ingot is air-cooled through controlled rolling and then subjected to low-temperature tempering heat treatment to obtain HB450 grade steel plate with excellent plasticity, toughness, and wear resistance.

[0029] 3) By controlling the Ni content, the austenite phase region is expanded, the amount of retained austenite in the steel is increased, and the retained austenite content in the steel is controlled to 5% to 8%, ensuring that the steel plate has good plasticity and toughness;

[0030] 4) Ensure that the steel plate has a -40°C AKV of ≥30J and an elongation A of ≥12%;

[0031] 5) Make the surface hardness of the steel plate ≥ HB450 and the tensile strength ≥ 1300MPa;

[0032] 6) Avoid heating cracking by controlling the temperature and soaking time of the heating soaking section, ensure that the alloy elements are fully dissolved, and effectively remove the casting internal stress in the steel billet by controlling the hot delivery or heating slow cooling and tempering temperature and time. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are further described below:

[0034] The chemical composition of the steel plate designed in this invention features microalloying of chromium, nickel, and niobium, resulting in a relatively low alloy content, facilitating smelting and continuous casting. The ingot is air-cooled through controlled rolling and then subjected to low-temperature tempering heat treatment, resulting in HB450-grade steel plate with excellent ductility, toughness, and wear resistance. The present invention provides an HB450 grade wear-resistant and corrosion-resistant steel plate. The chemical composition of the steel plate is as follows by weight: C: 0.20%-0.23%, Si: 0.2%-0.4%, Mn: 0.2%-0.4%, Nb: 0.10%-0.20%, Cr: 3.10%-3.30%, Al: 0.31%-0.40%, Ni: 1.0%-1.5%, 1.4%≤Al+Ni≤1.8%, and the balance is Fe and unavoidable impurities; impurity elements in the steel are controlled as follows: P≤0.012%, S≤0.002%, [N]≤0.0040%, [H]≤0.00015%, [O]≤0.0010%, and the retained austenite content is 5%-8%.

[0035] A method for producing HB450 grade wear-resistant and corrosion-resistant steel plates, comprising the following process steps: smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment; wherein:

[0036] 1) Refining: RH vacuum cycle time ≥ 16 min;

[0037] 2) Continuous casting: The thickness of the slab is 200-250mm, the target superheat of the tundish is controlled at ≤25℃, the casting is protected throughout, electromagnetic stirring or soft pressure is used, intermediate cooling is used in the secondary cooling zone, and the continuous casting slab pulling speed is controlled at 1.1-1.3m / min. After the continuous casting slab comes off the line, it is placed in a slow cooling pit for heating and slow cooling. The slab slow cooling starting temperature is required to be ≥400℃, and it is heated to 630-650℃ at a heating rate of ≤50℃ / second. After holding for 8-12 hours, it is slowly cooled to less than 400℃ with the furnace, and then air-cooled to room temperature.

[0038] 3) Rolling: The temperature of the heating and soaking section is 1200-1280°C, and the soaking time is greater than 2.0 hours. During rolling, two stages of controlled rolling are adopted, namely rough rolling and finishing rolling. The starting rolling temperature of the rough rolling stage is ≥1100°C, and the finishing rolling temperature is controlled at ≥1000°C; the starting rolling temperature of the finishing rolling is 950-1000°C, the finishing rolling reduction ratio is ≥60%, and the finishing rolling temperature is 870-920°C. After rolling, the steel is air-cooled to room temperature.

[0039] 4) Tempering heat treatment: The tempering temperature is 230-260°C, and the tempering holding time is 5-8 min / mm.

[0040] The chemical composition design reasons of the HB450 grade wear-resistant and corrosion-resistant steel plate described in the present invention are as follows:

[0041] C: To ensure that the martensite of the steel plate has a hardness of HB450 after air cooling, a considerable carbon content is required. At the same time, carbon can form carbides with Nb and Cr to precipitate, thereby increasing wear resistance. If the carbon content is too high, the low-temperature toughness decreases. To ensure that the steel plate has high wear resistance and good low-temperature toughness, the C content in the present invention is controlled within a range of 0.20% to 0.23%.

[0042] Si: Its main functions are solid solution strengthening and deoxidation. It is a non-carbide-forming element that dissolves in ferrite and austenite in the form of solid solution, improving the strength and hardness of steel. It has a significant solid solution strengthening effect. Therefore, the Si content in the present invention is controlled at 0.2% to 0.4%.

[0043] Mn: Its main function is solid solution strengthening. However, if its content is too high, it is easy to form central segregation, which makes the center of the slab prone to cracking. Therefore, in the present invention, the Mn content is controlled at 0.2% to 0.4%.

[0044] Nb: An important additive element in this patent, its main function is to increase wear resistance, refine grains and improve toughness. Nb is a strong carbon and nitrogen compound forming element. It combines with C and N in steel to form NbC and Nb(C,N) compounds, which have the characteristics of high chemical stability and high hardness, and improve the wear resistance of steel. In addition, the addition of 0.1% to 0.2% Nb element causes strain induction during the rolling process of low-temperature austenite structure, thereby causing a large amount of carbonitrides to precipitate, which has the effect of increasing hardenability and precipitation strengthening; Nb dissolved in austenite inhibits austenite recrystallization during the two-stage rolling process and refines the austenite grains. However, if the Nb content is too high, it will affect the mechanical properties of the steel plate. Therefore, in the present invention, the Nb content is controlled at 0.10% to 0.20%.

[0045] Al: An effective element for deoxidation and nitrogen fixation. It can reduce oxide inclusions in steel and purify steel. It can also expand the austenite phase region, which is beneficial to the stability of retained austenite. Too high an Al content will cause casting difficulties and form a large amount of Al2O3 inclusions in the steel, resulting in poor ductility. In order to control the austenite content in the steel to 5% to 8%, the Al content in the present invention is controlled to 0.31% to 0.40%.

[0046] Cr: This patent focuses on adding elements. An appropriate amount of Cr is beneficial to improving the natural corrosion potential of the material and plays a role in inhibiting corrosion, thereby reducing the occurrence of corrosion and ensuring the corrosion resistance of the steel. Cr can also reduce the critical cooling rate, improve the hardenability of the steel plate, form a fine martensite structure, and ensure that the hardness of the steel plate after air cooling is above 450HB. In addition, chromium is a strong carbide-forming element and can form a variety of carbides in steel to ensure the wear resistance of the steel plate. However, excessive addition of Cr will reduce the weldability. Therefore, the Cr content of the present invention is controlled at 3.10% to 3.30%.

[0047] Ni: It is beneficial to improve the natural corrosion potential of the steel plate and play a role in inhibiting corrosion, thereby reducing the occurrence of corrosion and ensuring the corrosion resistance of the steel. It can also expand the austenite phase region, increase the amount of retained austenite in the steel, and improve the toughness and plasticity of the steel. This patent controls Ni: 1.0~1.5%. Since Al and Ni both have the effect of promoting the content of retained austenite, this patent controls the retained austenite content at 5%~8%. In order to prevent the amount of retained austenite from being too much or too little, the total amount of Al+Ni is controlled. Therefore, this patent is 1.4%≤AL+Ni≤1.8%.

[0048] A high content of impurity elements will reduce plasticity and toughness. Therefore, in order to ensure good plasticity and toughness, the impurity elements P≤0.012%, S≤0.002%, [H]≤0.00015%, [O]≤0.0010%, and [N]≤0.0040% in this patent.

[0049] The design principle of the production method of the HB450 grade wear-resistant and corrosion-resistant steel plate described in the present invention is as follows:

[0050] The steel plate production method of the present invention includes the following process: smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment;

[0051] 1) Smelting process characteristics: The present invention carries out RH degassing time control during refining, and the RH vacuum cycle time is ≥16min. Through long-term vacuum treatment, the molten steel [N]≤0.0040%, [O]≤0.0010%, and [H]≤0.00015%. The continuous casting characteristics of the present invention are: the target superheat of the tundish is controlled at ≤25℃; the casting is protected throughout the process, the secondary cooling adopts a medium cooling intensity mode, the continuous casting billet pulling speed is controlled to 1.1-1.3m / min, and the billet thickness is 1.1-1.3m / min. The thickness is 200-250mm. Electromagnetic stirring or light pressure is used during continuous casting to reduce central segregation. In order to avoid cracking of the billet, the continuous casting billet is delivered hot. If hot delivery cannot be arranged, it will be put into the slow cooling pit for heating and slow cooling after leaving the line. The starting temperature of the slab slow cooling is required to be ≥400℃. It is heated to 630-650℃ at a heating rate of ≤50℃ / second. After keeping warm for 8-12 hours, it is slowly cooled to less than 400℃ with the furnace and air-cooled to room temperature. The purpose of heating and slow cooling is to effectively remove the hydrogen content and casting internal stress in the billet.

[0052] 2) Rolling process characteristics: The temperature of the heating and soaking section is 1200-1280°C, and the soaking time is greater than 2.0 hours. The purpose is to avoid heating cracking and ensure sufficient solid solution of alloy elements. Before rolling, the roller cooling water and controlled cooling water are turned off, and the roller cooling water is turned to the minimum; during rolling, two stages of rough rolling and finishing rolling are adopted. The purpose is to fully refine and homogenize the hot-rolled structure; the starting rolling temperature of the rough rolling stage is ≥1100°C, and the final rolling temperature is controlled at ≥1000°C; the starting rolling temperature of the finishing rolling is 950-1000°C, the finishing rolling reduction rate is ≥60%, the purpose is to refine the original austenite structure, and the final rolling temperature is 870-920°C; after rolling, the steel is air-cooled to room temperature.

[0053] 3) Heat treatment process characteristics: The tempering temperature is 230-260°C, and the tempering holding time is 5-8 min / mm. The purpose is to further remove the internal stress of the steel plate and improve the plasticity and toughness of the steel plate.

[0054] The following examples are implemented under the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operating processes, but the scope of protection of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0055] [Example]

[0056] According to the chemical composition and production process of the present invention, the actual chemical composition of the steel of the present invention is shown in Table 1, the smelting process is shown in Table 2, the actual rolling process parameters of the steel example of the present invention are shown in Table 3, the heat treatment process parameters are shown in Table 4, the actual performance test results of the present invention are shown in Table 5, and the wear resistance test results are shown in Table 6.

[0057] Table 1 Example of smelting composition of steel grades of the present invention, Wt%

[0058]

[0059] Table 2 Smelting process of steel grades of the present invention

[0060]

[0061] Table 3 Actual rolling process parameters of steel examples of the present invention

[0062]

[0063] Table 4 Heat treatment process of steel examples of the present invention

[0064]

[0065] Table 5 Mechanical properties of steel examples of the present invention

[0066]

[0067] The wear and corrosion resistance of the experimental steel was tested using a rotary corrosion wear tester. The slurry concentration was 3.5% NaCl in industrial tap water mixed with 75% quartz sand. The slurry rotated at a speed of 3 m / s. After rubbing against a standard cylindrical specimen, the weight loss was compared with that of ordinary NM450. The test lasted for 8 hours. The results are shown in Table 6.

[0068] Table 6 Comparison of wear resistance and corrosion resistance of the present invention

[0069] Steel Type Wear loss ΔM / g Corrosion resistance and wear resistance comparison Ordinary NM450 0.872 1 1-1 0.715 1.22 1-2 0.698 1.25 2-1 0.671 1.3 2-2 0.646 1.35 3-1 0.703 1.24 3-2 0.641 1.36 4-1 0.661 1.32 4-2 0.681 1.28

[0070] It can be seen that the wear resistance and corrosion resistance of the steel plate of the present invention are more than 1.2 times that of ordinary wear-resistant steel plates.

Claims

1. A HB450 grade wear-resistant and corrosion-resistant steel plate, characterized in that: The chemical composition of the steel plate is as follows by weight: C: 0.20% to 0.23%, Si: 0.2% to 0.4%, Mn: 0.2% to 0.4%, Nb: 0.10% to 0.20%, Cr: 3.10% to 3.30%, Al: 0.31% to 0.40%, Ni: 1.0% to 1.5%, 1.4%≤Al+Ni≤1.8%, the balance being Fe and unavoidable impurities; impurity element control in the steel: P≤0.012%, S≤0.002%, [N]≤0.0040%, [H]≤0.00015%, [O]≤0.0010%, and retained austenite content of 5% to 8%; The production method of the steel plate includes the following process: smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment; wherein: 1) Refining: RH vacuum cycle time ≥ 16min; 2) Continuous casting: The target superheat of the tundish is controlled at ≤25°C, and the casting process is protected. Electromagnetic stirring or soft reduction is used, and intermediate cooling is used in the secondary cooling zone. The continuous casting billet drawing speed is controlled at 1.1-1.3 m / min. 3) Rolling: The temperature of the heating and soaking section is 1200-1280℃, and the soaking time is greater than 2.0 hours. During rolling, two stages of controlled rolling are adopted, namely rough rolling and finishing rolling. The starting rolling temperature of the rough rolling stage is ≥1100℃, and the finishing rolling temperature is controlled at ≥1000℃; the starting rolling temperature of the finishing rolling is 950-1000℃, the finishing rolling reduction rate is ≥60%, and the finishing rolling temperature is 870-920℃. After rolling, the steel is air-cooled to room temperature. 4) Tempering heat treatment: The tempering temperature is 230-260℃, and the tempering holding time is 5-8min / mm.

2. A method for producing HB450 grade wear-resistant and corrosion-resistant steel plate according to claim 1, characterized in that: The production method of the steel plate includes the following process: smelting, refining, slab continuous casting, heating and slow cooling, slab heating, controlled rolling, steel plate slow cooling, and tempering heat treatment; wherein: 1) Refining: RH vacuum cycle time ≥ 16min; 2) Continuous casting: The target superheat of the tundish is controlled at ≤25°C, and the casting process is protected. Electromagnetic stirring or soft reduction is used, and intermediate cooling is used in the secondary cooling zone. The continuous casting billet drawing speed is controlled at 1.1-1.3 m / min. 3) Rolling: The temperature of the heating and soaking section is 1200-1280℃, and the soaking time is greater than 2.0 hours. During rolling, two stages of controlled rolling are adopted, namely rough rolling and finishing rolling. The starting rolling temperature of the rough rolling stage is ≥1100℃, and the finishing rolling temperature is controlled at ≥1000℃; the starting rolling temperature of the finishing rolling is 950-1000℃, the finishing rolling reduction rate is ≥60%, and the finishing rolling temperature is 870-920℃. After rolling, the steel is air-cooled to room temperature. 4) Tempering heat treatment: The tempering temperature is 230-260℃, and the tempering holding time is 5-8min / mm.

3. The method for producing HB450 grade wear-resistant and corrosion-resistant steel plate according to claim 2, characterized in that: After the continuous casting slab comes off the line, it enters the slow cooling pit for heating and slow cooling. The starting temperature of the slab slow cooling is required to be ≥400℃, and it is heated to 630-650℃ at a heating rate of ≤50℃ / second. After keeping warm for 8-12 hours, it is slowly cooled to less than 400℃ with the furnace and air-cooled to room temperature.

4. The method for producing HB450 grade wear-resistant and corrosion-resistant steel plate according to claim 2, characterized in that: The surface hardness of the steel plate is ≥HB450, the tensile strength is ≥1300MPa, and the corrosion resistance and wear resistance are more than 1.2 times that of ordinary NM450.

5. The method for producing HB450 grade wear-resistant and corrosion-resistant steel plate according to claim 2, characterized in that: The thickness of the casting billet is 200 to 250 mm.

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