A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel

Abstract

The present invention relates to a method for preparing a low-stress, high-toughness, thin-gauge wear-resistant steel. The method produces a low-stress, high-toughness, thin-gauge wear-resistant steel plate by combining specific component design with offline heat treatment. The specific component design is to use laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, and the nickel content is controlled to be 0.50-2.00wt.%; the hot-rolled steel plate is coiled and flattened and then subjected to offline heat treatment, and the offline heat treatment adopts roller-type restrained quenching and low-temperature tempering through hot air flue gas circulation heating. The method simplifies the production process, reduces the production cost, and improves the strength, toughness and formability of the wear-resistant steel; produces a low-stress, high-toughness, thin-gauge wear-resistant steel, the steel plate hardness is 360-500HB, the tensile strength is 1100-1650MPa, the elongation is 11%-15%, the steel plate residual stress is below 100MPa, and the impact toughness at -60℃ can reach 50J / cm 2 above.

Description

Technical Field

[0001] The invention relates to a method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, and belongs to the technical field of wear-resistant steel plate manufacturing. Background Art

[0002] As the grade of wear-resistant steel increases, the carbon content in the steel increases, the hardness increases, the toughness decreases, and the formability becomes worse. In industrial industries such as engineering machinery and equipment manufacturing, a large amount of wear-resistant steel is used. Some workpieces have complex shapes and the preparation process requires bending and forming. Therefore, there are certain requirements for the toughness and formability of the steel plate. High-strength thin-gauge steel plates are more sensitive to internal stress, and the plate shape is difficult to control, which can easily cause deformation of the steel plate itself or deformation after cutting and bending. In addition, ultra-high-strength steel plates of 1000MPa and above have large residual internal stress after quenching, and require low-temperature tempering to eliminate internal stress, reduce the risk of delayed cracking, and regulate the structure. The existing tempering equipment uses flame or radiation tube heating, and cannot accurately control below 300°C. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In order to solve the above problems in the prior art, the present invention provides a method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, which is prepared by combining specific component design with roller-type constrained quenching and hot air and flue gas circulation heating with high-precision low-temperature tempering.

[0005] (II) Technical solution

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel is provided. The method produces low-stress, high-toughness, thin-gauge wear-resistant steel plates by combining specific component design with offline heat treatment. The specific component design uses laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, and the nickel content is controlled to be 0.50-2.00wt.%. The hot-rolled steel plates are coiled and flattened and then subjected to offline heat treatment. The offline heat treatment uses roller-type restrained quenching and low-temperature tempering through hot air and flue gas circulation heating.

[0008] The specific preparation process includes smelting, casting, continuous casting billet heating, rolling, coiling cooling and offline heat treatment.

[0009] According to the preparation method as described above, preferably, the chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.10-0.15; Ni: 0.50-1.00; Ti: 0.01-0.02; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.20-0.30; N≤0.004; S≤0.003; P≤0.008; the remainder is Fe and unavoidable impurity elements.

[0010] Appropriate amounts of Nb and V can be added, and the sum of Nb, V and Ti is less than 0.02%. The addition of Nb, V and Ti can be selected based on the actual situation and whether it is necessary to refine the grains. The obtained steel plate mechanical properties: the steel plate hardness is above 360HB, the tensile strength is greater than 1100MPa, the elongation is greater than 12%, and the -60℃ impact toughness is greater than 100J / cm 2 , the residual stress is lower than 90MPa.

[0011] According to the preparation method described above, preferably, the chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.15-0.20; Ni: 1.00-1.50; Ti: 0.01-0.02; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.30-0.40; N≤0.004; S≤0.003; P≤0.008; the remainder is Fe and unavoidable impurity elements, and appropriate amounts of Nb and V may be added, and the sum of Nb, V and Ti is less than 0.02%; the mechanical properties of the steel plate are as follows: the hardness of the steel plate is above 400HB, the tensile strength is greater than 1400MPa, the elongation is greater than 12%, and the impact toughness at -60°C is greater than 70J / cm 2 , the residual stress is lower than 90MPa.

[0012] According to the preparation method described above, preferably, the chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.20-0.25; Ni: 1.50-2.00; Ti: 0.02-0.03; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.40-0.50; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements, and appropriate amounts of Nb and V can be added, and the sum of Nb, V and Ti is less than 0.03%. The mechanical properties of the steel plate obtained are: the hardness of the steel plate is above 450HB, the tensile strength is greater than 1600MPa, the elongation is greater than 11%, and the impact toughness at -60℃ is greater than 50J / cm 2 , the residual stress is less than 100MPa.

[0013] In the preparation method as described above, preferably, the nickel content in the laterite nickel ore is 0.8%-1.5% by weight, and the iron content is 30%-50% by weight.

[0014] In the preparation method as described above, preferably, the hot-rolled steel plate is cooled to between 550-650° C. for coiling, and then air-cooled to room temperature after coiling;

[0015] The coiled steel coil is leveled and the unevenness after leveling is controlled within 6mm / m.

[0016] According to the preparation method as described above, preferably, the coiled steel coil is uncoiled, straightened, sheared to length, and then subjected to offline heat treatment, the quenching temperature of the constrained quenching is 850-900°C, and the heating time coefficient is 1.7-2.1 min / mm; the tempering temperature of the low-temperature tempering is 150-220°C, and the holding time coefficient is 4.5-6 min / mm; wherein the time coefficient refers to the ratio of the required time to the thickness of the steel plate.

[0017] There is no need for straightening after heat treatment, and the unevenness of the steel plate is within 2mm / m.

[0018] According to the preparation method as described above, preferably, the first stage of constrained quenching is in quenching and cooling zones 1 to 2, and hydraulic annular pressure rollers are used for constrained quenching. The upper pressure roller of the hydraulic annular pressure roller is adjustable, and its working stroke range is 4mm to 6mm, and the constraining force applied to the quenched steel plate is between 30-70kN; the second stage is in quenching and cooling zones 3 to 4, and hydraulic flat pressure rollers are used for constrained quenching. The upper pressure roller of the hydraulic flat pressure roller is adjustable, and its working stroke range is 3mm to 7mm, and the constraining force applied to the quenched steel plate is between 20-60kN; the third stage is in quenching and cooling zones 5 to 6, and ordinary flat pressure rollers are used for constrained quenching. The upper pressure roller of the ordinary flat pressure roller is adjustable, and its working stroke range is 3mm to 7mm, and the constraining force applied to the quenched steel plate is between 30-70kN.

[0019] In the preparation method as described above, preferably, the deviation of the low-temperature tempering by hot air and flue gas circulation heating is within the range of ±3°C.

[0020] (III) Beneficial effects

[0021] The beneficial effects of the present invention are:

[0022] The present invention provides a method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, in which low-cost laterite nickel ore is used instead of nickel alloy to produce high-toughness wear-resistant steel, and the nickel element in the laterite nickel ore is fully utilized without the need to add additional nickel alloy, thereby simplifying the production process, reducing the composition, and improving the toughness and formability of the wear-resistant steel. The present invention produces low-stress, high-toughness, thin-gauge wear-resistant steel, the steel plate hardness of which is 360-500HB, the tensile strength is 1100-1650MPa, the elongation is 11%-15%, the residual stress of the steel plate is below 100MPa, and the impact toughness at -60°C can reach 50J / cm2 Above, no straightening is required after heat treatment, and the unevenness of the steel plate is within 2mm / m. DETAILED DESCRIPTION

[0023] The present invention provides a method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel. Low-stress, high-toughness, thin-gauge wear-resistant steel plates are prepared by combining specific component design with roller-type constrained quenching and hot air flue gas circulation heating high-precision low-temperature tempering. Specific component design refers to the use of cheap laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, making full use of the nickel element in the laterite nickel ore without the need to add additional nickel alloy, simplifying the production process, reducing the composition, and improving the strength, toughness and formability of the wear-resistant steel. The present invention can produce low-stress, high-toughness, thin-gauge wear-resistant steel with a thickness range of 2-25.4mm, a steel plate hardness of 360-500HB, a tensile strength of 1100-1650MPa, an elongation of 11%-15%, a steel plate residual stress below 100MPa, and an impact toughness of up to 50J / cm at -60°C. 2 Above, no straightening is required after heat treatment, and the unevenness of the steel plate is within 2mm / m.

[0024] Composition characteristics: Using cheap laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, fully utilizing the nickel element in laterite nickel ore, without the need to add additional nickel alloy, simplifying the production process, reducing the composition, while improving the strength, toughness and formability of the wear-resistant steel.

[0025] The nickel content in the laterite nickel ore is 0.8%-1.5% by weight, and the iron content is 30%-50%. The nickel element can improve the toughness of wear-resistant steel. According to the ratio of nickel and iron elements in the selected laterite nickel ore, the nickel content is controlled to be 0.50-2.00wt.%.

[0026] Offline heat treatment characteristics: (1) Roller-type constrained quenching can achieve good control of the shape of thin-gauge steel plates. (2) Low-temperature tempering at 150-220°C can be achieved by circulating hot air and flue gas heating, and low-temperature high-precision tempering at low temperature of ±3°C can be achieved. Uniform tempering can effectively reduce residual stress.

[0027] The effect of constrained quenching is: in the rapid cooling zone, there is a large internal stress in the plate and strip. The hydraulic annular pressure roller, hydraulic flat pressure roller and ordinary flat pressure roller act on the upper and lower surfaces of the plate and strip with a large roller pressure. The constraint force is set to be greater than or equal to the yield strength of the steel plate when quenched in the high temperature section. The application of external constraint force during the quenching process ensures that the plate and strip have good quenching straightness, while promoting the release of internal stress in the plate and strip to obtain low internal stress products and obtain good bending forming performance.

[0028] The constrained quenching is a roller quenching machine that uses a hydraulic pressing / lifting system to achieve the movement of the upper frame-upper roller system-upper nozzle. A three-stage independent hydraulic fixed-moving frame is designed to meet the 10-ton hydraulic pressing requirement and achieve strong constraint control of the quenching shape of thin-gauge steel plates. Before the steel plate bites into the roller system, the hydraulic system implements constant roller gap control (constant position control). After the steel plate bites in, if quenching deformation occurs, pressure control is implemented.

[0029] The hot air flue gas circulation allows most of the hot air to circulate in the tempering furnace, ensuring the uniformity of temperature in various parts of the steel plate, and can achieve low-temperature high-precision tempering of ±3°C. The uniform temperature distribution can effectively reduce residual stress. At the same time, the hot air circulation has high thermal efficiency and can save energy.

[0030] The Ni element can improve the low-temperature toughness, but the Ni element is relatively expensive. Excessive addition will lead to excessive cost of the steel plate, so the Ni content is controlled between 0.5% and 2%. In addition, the use of cheap laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel makes full use of the nickel element in the laterite nickel ore without the need to add additional nickel alloy, which simplifies the production process, reduces the composition, and improves the strength, toughness and formability of the wear-resistant steel.

[0031] In the preparation method of the present invention, by adopting roller-type constrained quenching, good control of the plate shape of thin gauge steel plates can be achieved. Low-temperature tempering at 150-220°C can be performed by circulating hot air and flue gas heating, and low-temperature high-precision tempering at low temperature ±3°C can be achieved, and uniform tempering can effectively reduce residual stress. Through the above process, a thin gauge wear-resistant steel plate with high toughness and low stress and good plate shape can be obtained.

[0032] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific embodiments. The mechanical properties of the steel plates obtained in the following examples and comparative examples are measured according to the room temperature tensile test method of metal materials in GB / T228-2002, the low temperature impact toughness is measured according to the Charpy pendulum impact test method of metal materials in GB / T229-2007, the hardness is measured according to the GB / T231.1-2009 method, the residual stress is measured by X-ray diffraction, and the unevenness is measured by Q / BQB 401-2018 method.

[0033] Example 1

[0034] The invention discloses a method for preparing a low-stress, high-toughness, thin-gauge wear-resistant steel. The chemical composition of the wear-resistant steel is C: 0.13; Ni: 0.80; Ti: 0.015; Mn: 0.80; Si: 0.25; Mo: 0.25; N≤0.004; S≤0.003; P≤0.008; the balance is Fe. The source of Ni used is cheap laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel. The nickel content in the laterite nickel ore is 1% by weight and the iron content is 40% by weight.

[0035] The specific preparation process includes smelting, casting, continuous casting billet heating, rolling, coiling cooling and off-line heat treatment. Anything not described in detail below can be done by conventional means in the art, which will not be described in detail here.

[0036] The steel plate hot rolled to 4 mm is cooled in stages, that is, it is first quickly cooled to 550°C and then coiled, and then air-cooled to room temperature after coiling.

[0037] The coiled steel coil is flattened and the unevenness after flattening is controlled to 6mm / m.

[0038] After rolling, the steel is subjected to offline heat treatment, with a quenching temperature of 880°C, a heating time of 1 hour, a tempering temperature of 220°C, and a holding time of 2.5 hours. The steel is quenched using a roller quenching machine to ensure a good plate shape. In the first stage of constrained quenching, hydraulic annular rollers are used for constrained quenching in quenching and cooling zones 1 and 2. The upper roller of the hydraulic annular roller is adjustable, and its working stroke range is 4mm to 6mm. The constraining force applied to the quenched steel plate is between 50-90kN. In the second stage, hydraulic flat rollers are used for constrained quenching in quenching and cooling zones 3 and 4. The upper roller of the hydraulic flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 40-80kN. In the third stage, ordinary flat rollers are used for constrained quenching in quenching and cooling zones 5 and 6. The upper roller of the ordinary flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 50-90kN. Using hot air and flue gas circulation heating for low-temperature tempering can achieve low-temperature high-precision tempering at low temperature ±3℃ and reduce the residual internal stress of the steel plate.

[0039] The obtained 4mm thick steel plate was tested for hardness, tensile strength, elongation, -60℃ impact toughness residual stress, and unevenness. The hardness of the steel plate was 373HB, the tensile strength was 1180MPa, the elongation was 15%, and the -60℃ impact toughness was 103J / cm 2 , the residual stress is 79MPa and the roughness is 0.8mm / m.

[0040] Example 2

[0041] A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, the chemical composition of which is C: 0.19, Ni: 1.30, Ti: 0.015, Mn: 0.80, Si: 0.25, Mo: 0.35, N≤0.004, S≤0.003, P≤0.008, and the balance is Fe and unavoidable impurity elements.

[0042] The nickel content in the laterite nickel ore is 1% by weight and the iron content is 40% by weight.

[0043] The specific preparation process includes smelting, casting, continuous casting billet heating, rolling, coiling cooling and off-line heat treatment.

[0044] The steel plate hot-rolled to 4 mm was cooled in stages, coiled after cooling to 600°C, and then air-cooled to room temperature.

[0045] The coiled steel coil is flattened and the unevenness after flattening is controlled to 6mm / m.

[0046] After rolling, the steel is subjected to offline heat treatment, with a quenching temperature of 880°C, a heating time of 1 hour, a tempering temperature of 220°C, and a holding time of 2.5 hours. The steel is quenched using a roller quenching machine to ensure a good plate shape. In the first stage of constrained quenching, hydraulic annular rollers are used for constrained quenching in quenching and cooling zones 1 and 2. The upper roller of the hydraulic annular roller is adjustable, and its working stroke range is 4mm to 6mm. The constraining force applied to the quenched steel plate is between 40-80kN. In the second stage, hydraulic flat rollers are used for constrained quenching in quenching and cooling zones 3 and 4. The upper roller of the hydraulic flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 30-70kN. In the third stage, ordinary flat rollers are used for constrained quenching in quenching and cooling zones 5 and 6. The upper roller of the ordinary flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 40-80kN. Using hot air and flue gas circulation heating for low-temperature tempering can achieve low-temperature high-precision tempering at low temperature ±3℃ and reduce the residual internal stress of the steel plate.

[0047] The steel plate has a hardness of 443HB, a tensile strength of 1457MPa, an elongation of 13.1%, and an impact toughness of 75J / cm at -60℃. 2 , the residual stress is 87MPa and the roughness is 1.2mm / m.

[0048] Example 3

[0049] A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, wherein the chemical composition is C: 0.25; Ni: 1.80; Ti: 0.025; Mn: 0.80; Si: 0.25; Mo: 0.45; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements, and the high-toughness wear-resistant steel is produced by using cheap laterite nickel ore instead of nickel alloy, wherein the nickel content in the laterite nickel ore is 1% by mass and the iron content is 40% by mass. The specific preparation process includes smelting, casting, continuous casting billet heating, rolling, coiling cooling and offline heat treatment.

[0050] The steel plate hot-rolled to 4 mm was cooled in stages, coiled after cooling to 600°C, and then air-cooled to room temperature.

[0051] The coiled steel coil is flattened and the unevenness after flattening is controlled to 6mm / m.

[0052] After rolling, the steel is subjected to offline heat treatment, with a quenching temperature of 880°C, a heating time of 1 hour, a tempering temperature of 220°C, and a holding time of 2.5 hours. The steel is quenched using a roller quenching machine to ensure a good plate shape. In the first stage of constrained quenching, hydraulic annular rollers are used for constrained quenching in quenching and cooling zones 1 and 2. The upper roller of the hydraulic annular roller is adjustable, and its working stroke range is 4mm to 6mm. The constraining force applied to the quenched steel plate is between 30-70kN. In the second stage, hydraulic flat rollers are used for constrained quenching in quenching and cooling zones 3 and 4. The upper roller of the hydraulic flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 20-60kN. In the third stage, ordinary flat rollers are used for constrained quenching in quenching and cooling zones 5 and 6. The upper roller of the ordinary flat roller is adjustable, and its working stroke range is 3mm to 7mm. The constraining force applied to the quenched steel plate is between 30-70kN. Using hot air and flue gas circulation heating for low-temperature tempering can achieve low-temperature high-precision tempering at low temperature ±3℃ and reduce the residual internal stress of the steel plate.

[0053] The steel plate has a hardness of 489HB, a tensile strength of 1650MPa, an elongation of 11.8%, and an impact toughness of 53J / cm at -60℃. 2 , the residual stress is 95MPa and the roughness is 1.8mm / m.

[0054] Comparative Example

[0055] A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, the chemical composition of which is C: 0.25; Ni: 1.80; Ti: 0.025; Mn: 0.80; Si: 0.25; Mo: 0.45; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and inevitable impurity elements, and the high-toughness wear-resistant steel is produced by using cheap laterite nickel ore instead of nickel alloy, the nickel content in the laterite nickel ore is 1% by weight and the iron content is 40% by weight.

[0056] The specific preparation process includes smelting, casting, continuous casting billet heating, rolling, coiling cooling and off-line heat treatment.

[0057] The steel plate hot-rolled to 4 mm was cooled in stages, coiled after cooling to 600°C, and then air-cooled to room temperature.

[0058] The coiled steel coil is flattened and the unevenness after flattening is controlled to 6mm / m.

[0059] After rolling, the steel is subjected to off-line heat treatment, with a quenching temperature of 880°C, a heating time of 1 hour, a tempering temperature of 220°C, and a holding time of 2.5 hours. The off-line heat treatment uses conventional non-roller quenching equipment and flame or radiation tube heating tempering equipment.

[0060] The steel plate has a hardness of 489HB, a tensile strength of 1650MPa, an elongation of 11.8%, and an impact toughness of 38J / cm at -60℃. 2 , the residual stress is 150MPa and the roughness is 4mm / m.

[0061] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any person skilled in the art can use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing low-stress, high-toughness, thin-gauge wear-resistant steel, characterized in that: The invention relates to producing a low-stress, high-toughness, thin-gauge wear-resistant steel plate by combining a specific composition design with an offline heat treatment, wherein the specific composition design uses laterite nickel ore instead of nickel alloy to produce high-toughness wear-resistant steel, and the nickel content is controlled to be 0.50-2.00 wt.%, and the chemical composition of the wear-resistant steel is as follows: C: 0.10-0.25 in weight percentage; Ni: 0.50-2.00; Ti: 0.01-0.03; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.20-0.50; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements; the hot-rolled steel plate is coiled and flattened and then subjected to offline heat treatment, wherein the offline heat treatment adopts roller-type restrained quenching and low-temperature tempering by hot air and flue gas circulation heating; The coiled steel coil is uncoiled, straightened, cut to length, and then subjected to offline heat treatment. The quenching temperature of the constrained quenching is 850-900 °C, and the heating time coefficient is 1.7-2.1 min / mm; the tempering temperature of the low-temperature tempering is 150-220 °C, and the holding time coefficient is 4.5-6 min / mm; wherein the time coefficient refers to the ratio of the required time to the thickness of the steel plate; The first stage of the constrained quenching is in the quenching cooling zone 1 to 2, and the hydraulic annular roller is used for constrained quenching. The upper roller of the hydraulic annular roller is adjustable, and its working stroke range is 4 mm to 6 mm. The constraining force applied to the quenched steel plate is between 30-70 kN; the second stage is in the quenching cooling zone 3 to 4, and the hydraulic flat roller is used for constrained quenching. The upper roller of the hydraulic flat roller is adjustable, and its working stroke range is 3 mm to 7 mm. The constraining force applied to the quenched steel plate is between 20-60 kN; the third stage is in the quenching cooling zone 5 to 6, and the ordinary flat roller is used for constrained quenching. The upper roller of the ordinary flat roller is adjustable, and its working stroke range is 3 mm to 7 mm. The constraining force applied to the quenched steel plate is between 30-70 kN. The deviation of the low temperature tempering by hot air and flue gas circulation heating is within the range of ±3°C.

2. The preparation method according to claim 1, characterized in that The chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.10-0.15; Ni: 0.50-1.00; Ti: 0.01-0.02; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.20-0.30; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements.

3. The preparation method according to claim 1, characterized in that: The chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.15-0.20; Ni: 1.00-1.50; Ti: 0.01-0.02; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.30-0.40; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements.

4. The preparation method according to claim 1, characterized in that: The chemical composition of the wear-resistant steel is as follows by weight percentage: C: 0.20-0.25; Ni: 1.50-2.00; Ti: 0.02-0.03; Mn: 0.50-1.00; Si: 0.20-0.30; Mo: 0.40-0.50; N≤0.004; S≤0.003; P≤0.008; the balance is Fe and unavoidable impurity elements, and appropriate amounts of Nb and V may be added, and the sum of Nb, V and Ti is less than 0.03%.

5. The preparation method according to claim 1, characterized in that: The nickel content in the laterite nickel ore is 0.8%-1.5% by weight, and the iron content is 30%-50% by weight.

6. The preparation method according to claim 1, characterized in that: The hot-rolled steel plate is cooled to 550-650° C. for coiling, and then air-cooled to room temperature.

7. The preparation method according to claim 6, characterized in that: The coiled steel coil is leveled and the unevenness after leveling is controlled at 6 mm / m.