A low-cost corrosion and wear resistant steel sheet having low-temperature toughness and a method of manufacturing the same

Abstract

The application belongs to the field of wear-resistant steel and its preparation, and discloses a low-cost corrosion-resistant wear-resistant steel plate with low-temperature toughness and a preparation method thereof. The steel plate comprises the following chemical components in percentage by mass: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S: ≤0.005%, P: ≤0.003%, and the balance of Fe and inevitable impurities. The structure is mainly tempered lath martensite, and is accompanied by chromium carbide precipitated phase with a size of less than 100 nm. The hardness of the steel plate is greater than or equal to 470 HV, the impact energy at-40 DEG C is greater than or equal to 90 J, the tensile strength is greater than or equal to 1450 MPa, and the elongation is greater than or equal to 11%. The steel plate has excellent corrosion-resistant wear-resistant performance, and can be widely applied to wear-resistant parts under corrosion conditions in mining machinery, metallurgical machinery, cement and chemical machinery.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wear-resistant steel and its preparation, and particularly relates to a low-cost corrosion-resistant wear-resistant steel plate with low-temperature toughness and a preparation method thereof. BACKGROUND

[0002] Low-alloy wear-resistant steel is widely used as wear-resistant parts of engineering machinery, mining machinery, metallurgical machinery and cement chemical machinery due to its low price and high hardness. When such machinery works, the wear-resistant parts are subjected to the interaction of external load and abrasive particles, resulting in continuous damage to the surface of the parts, thereby causing wear failure. Excessive wear failure can even cause serious mechanical accidents. Therefore, in order to prolong the service life of the machinery and protect the safety of the workers, high-hardness martensitic wear-resistant steel is usually used for wear-resistant parts to resist wear by virtue of the high hardness of the martensitic structure.

[0003] However, the working environment of actual machinery is complex and changeable, involving dry or humid, normal or low temperature, high-acid or high-alkali environments. At present, the existing low-alloy wear-resistant steel plate only considers the wear resistance in ordinary environments, and although the wear resistance is good, the anti-wear ability in corrosive environments is not ideal, resulting in serious corrosion and wear of mechanical equipment such as garbage storage and transportation, coal mining and transportation, and sand conveying. When the machinery works in a corrosive environment, external corrosion can accelerate the wear of the parts, and wear can further accelerate corrosion, and the superimposed effect of the two leads to serious corrosion and wear. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the application provides a low-cost corrosion-resistant wear-resistant steel plate with low-temperature toughness and a preparation method thereof, wherein the low-cost corrosion-resistant wear-resistant steel plate with low-temperature toughness solves the technical problem of poor anti-wear ability of the existing low-alloy wear-resistant steel plate in a corrosive environment.

[0006] (II) Technical solutions

[0007] In order to achieve the above-mentioned purposes, the main technical solutions adopted by the application include:

[0008] The application provides, in a first aspect, a low-cost corrosion-resistant wear-resistant steel plate with low-temperature toughness,

[0009] The chemical components in the corrosion-resistant wear-resistant steel plate are as follows in terms of mass percentage: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S≤0.005% and P≤0.003%, and the balance is Fe and unavoidable impurities;

[0010] The microstructure of the anti-corrosion wear steel plate comprises tempered lath martensite and chromium carbide precipitates, wherein the volume fraction of the tempered lath martensite is ≥ 99%, and the size of the chromium carbide precipitates is ≤ 100 nm.

[0011] Further, the Cr content and the C content satisfy: Cr / C ≥ 14.

[0012] Further, the chemical composition of the anti-corrosion wear steel plate further comprises, in terms of mass percentage, at least one of: Nb: 0.005-0.05%, V: 0.00-0.05%, and Ti: 0.005-0.05%.

[0013] Further, the low-cost anti-corrosion wear steel plate with low-temperature toughness has a hardness ≥ 470 HV, an impact energy at -40°C ≥ 90 J, a tensile strength ≥ 1400 MPa, and an elongation ≥ 11%.

[0014] The second aspect of the present application refers to a preparation method of a low-cost anti-corrosion wear steel plate with low-temperature toughness, for preparing the low-cost anti-corrosion wear steel plate with low-temperature toughness of the first aspect, the method comprising:

[0015] Step S1 smelting: smelting and pouring to obtain a steel ingot according to the chemical composition in terms of mass percentage: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S ≤ 0.005%, P ≤ 0.003%, and the balance of Fe and inevitable impurities, the smelting temperature is controlled to be 1600-1700°C, an LF refining furnace and an RH refining furnace are used for treatment, the superheat of the molten steel in the tundish is ≤ 20°C, and the whole smelting process is protected by casting;

[0016] Step S2 forging: heating the steel ingot to 1150-1250°C and heating and holding, homogenizing for 1-4 h, and then forging at a forging temperature of 1150-1000°C to obtain a forged blank;

[0017] Step S3 rolling: heating the forged blank to 1050-1150°C and holding, and controlling the holding time of the rolling to be 1-4 h, and then performing recrystallization rolling and non-recrystallization rolling, controlling the total rolling pass number of the recrystallization rolling and the non-recrystallization rolling to be 6-9 passes, the total deformation amount ≥ 88%, the final rolling thickness is 8-20 mm, obtaining a hot-rolled steel plate, and air cooling the hot-rolled steel plate to room temperature;

[0018] Step S4 quenching: quenching and holding the hot-rolled steel plate at 850-950°C, and controlling the holding time of the quenching to be 10-40 min, and then water quenching to room temperature to obtain a quenched steel plate;

[0019] Step S5: tempering the quenched steel plate at 160-240 DEG C and holding, and controlling the tempering holding time to be 20-50 min, and then air cooling to room temperature to obtain a low-cost corrosion and wear resistant steel plate with low temperature toughness.

[0020] Further, the holding time in steps S2-S5 is:

[0021] τ≥0.02×δ[1.25×(C+Si)]

[0022] Wherein, τ is the heating holding time, rolling holding time, quenching holding time or tempering holding time (h), δ is the wall thickness of the holding product in the τ time (mm), C and Si are the carbon and silicon content of the holding product in the τ time (%).

[0023] Further, step S3 further comprises:

[0024] The recrystallization rolling temperature is 1050-950 DEG C, the rolling times are 3-4, and the single pass reduction rate is ≥25%;

[0025] The unrecrystallization rolling temperature is 900-800 DEG C, the rolling times are 3-5, and the single pass reduction rate is ≥20%.

[0026] Further, step S2 further comprises: heating the ingot to 1170-1230 DEG C and holding.

[0027] Further, step S3 further comprises: heating the forging blank to 1080-1120 DEG C and holding.

[0028] Further, step S4 further comprises: quenching the hot-rolled steel plate at 880-920 DEG C and holding, and controlling the quenching holding time to be 10-30 min, and then water quenching to room temperature to obtain a quenched steel plate;

[0029] Step S5 further comprises: tempering the quenched steel plate at 180-220 DEG C and holding, and controlling the tempering holding time to be 30-50 min, and then air cooling to room temperature to obtain a low-cost corrosion and wear resistant steel plate with low temperature toughness.

[0030] (Three) beneficial effects

[0031] The beneficial effects of the present application are:

[0032] The chemical components in the anti-corrosion wear-resistant steel plate provided by the application are as follows in percentage by mass: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S≤0.005% and P≤0.003%, and the balance is Fe and inevitable impurities; the microstructure of the anti-corrosion wear-resistant steel plate comprises tempered lath martensite and chromium carbide precipitates, wherein the volume fraction of the tempered lath martensite is ≥99%, and the size of the chromium carbide precipitates is ≤100nm.

[0033] The application reduces the combination of Cr and C by adding Cr element and strictly controlling the ratio of Cr content to C content, ensures sufficient Cr element in the steel, fully realizes the corrosion resistance of Cr element, and further improves the corrosion resistance by adding a certain amount of corrosion-resistant elements Cu and Sb. Compared with the traditional NM450 steel, the anti-corrosion wear-resistant steel of the application has the wear resistance in ordinary environment increased by 1.43 times, the wear resistance in deionized water increased by 1.46 times, and the wear resistance in 3.5% NaCl solution increased by 2.14 times. The microstructure is tempered lath martensite and fine chromium carbide precipitates, the hardness of the steel plate is ≥470HV, the impact energy at-40℃ is ≥90J, the tensile strength is ≥1450MPa, and the elongation is ≥11%, and the steel plate has excellent mechanical properties and anti-corrosion wear-resistant performance, and is suitable for wear parts under complex working conditions (normal temperature, low temperature, ordinary environment and corrosion environment). BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 The microstructure diagram of the steel plate of embodiment 4 of the low-cost anti-corrosion wear-resistant steel plate with low-temperature toughness mentioned in the application;

[0035] Figure 2 The process flow chart of the preparation method of the low-cost anti-corrosion wear-resistant steel plate with low-temperature toughness mentioned in the application. DETAILED DESCRIPTION

[0036] In order to better explain the application and facilitate understanding, the application is described in detail in combination with the specific embodiments and the accompanying drawings.

[0037] When equivalent, concentration, or other value or parameter is expressed in a range, a preferred range, or a series of upper preferred values and lower preferred values, it is to be understood that all ranges formed by any pair of any upper range limit or preferred value and any lower range limit or preferred value, even if the range is not explicitly disclosed, are to be specifically disclosed. For example, when a range "1-5" is disclosed, the described range is to be construed as including ranges "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5", etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include all integers and fractions within the range.

[0038] In these embodiments, the parts and percentages described are by mass. "Parts by mass" refers to a basic unit of measurement that represents the proportional relationship of the mass of multiple components, 1 part can represent any unit mass, such as 1 g, 3.527 g, etc. If we say that the mass of component A is a parts, and the mass of component B is b parts, it means that the mass ratio of component A to component B is a:b. Alternatively, it means that the mass of component A is aK, and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It must not be misunderstood that, unlike parts by mass, the sum of the parts by mass of all components is not limited to 100 parts. "And / or" is used to indicate that one or both of the described situations can occur, for example, A and / or B includes (A and B) and (A or B).

[0039] The present application provides, in a first aspect, a low-cost corrosion and wear resistant steel plate with low-temperature toughness,

[0040] The chemical composition of the corrosion and wear resistant steel plate is as follows in terms of mass percentage: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S≤0.005%, and P≤0.003%, with the balance being Fe and unavoidable impurities.

[0041] The microstructure of the corrosion and wear resistant steel plate includes tempered lath martensite and chromium carbide precipitates, wherein the volume fraction of the tempered lath martensite is ≥99%, and the size of the chromium carbide precipitates is ≤100 nm.

[0042] In an embodiment of the present application, the Cr content and the C content are as follows: Cr / C≥14.

[0043] The roles of the various element components in the steel plate of the present application are as follows:

[0044] C: C element is one of the main elements of wear-resistant steel, which has a significant effect on improving the strength of the steel. When the content of C is less than 0.1%, the C element has no obvious strengthening effect on the steel, but when the content of C is greater than 0.2%, the welding performance and processing performance of the steel are reduced; at the same time, too high C content can combine with Cr to form carbide to affect the low temperature toughness and corrosion resistance. Therefore, the content of carbon element is limited to 0.1-0.2%, preferably 0.14-0.18%.

[0045] Si: Si element is used as a deoxidizer, and can also be dissolved in austenite and ferrite, which has a significant benefit on improving the strength of the steel. When the content of Si element is less than 0.3%, the performance of the steel is not improved enough, but when the content is increased to more than 0.7%, inclusions are easily produced to reduce toughness. Therefore, the content of silicon element is limited to 0.3-0.7%, preferably 0.40-0.60%.

[0046] Mn: The effect of Mn element on the steel is mainly to improve the hardenability, in order to ensure sufficient hardenability, the content of Mn should be more than 0.3%, but too high Mn content can easily lead to the segregation of impurities such as MnS at the grain boundary to reduce toughness. Therefore, the content of manganese element is limited to 0.3-0.5%, preferably 0.35-0.45%.

[0047] Cu: Cu can improve the stability of austenite in steel, and the content should be greater than 0.2% to improve the hardenability; at the same time, Cu has the ability to resist atmospheric corrosion in steel, especially when used with P element, the effect is more significant; but when the content of Cu is greater than 0.5%, hot brittleness will be produced, and the processing performance will also decrease. Therefore, the content of copper element is limited to 0.2-0.5%, preferably 0.30-0.40%.

[0048] Cr: Cr is the most important element in the present application, which has good corrosion resistance stability and very high oxidation resistance, mainly plays a role in corrosion resistance in the steel of the present application, and can also improve the hardenability and hardness of the steel, and significantly improve the wear resistance of the steel. Therefore, the content of Cr should be more than 1.5%, but too high Cr content will affect the welding performance and toughness, and the cost will also increase, the content of Cr in the present application is selected to be less than 3.5%. At the same time, the effect of Cr on improving corrosion resistance will decrease with the increase of carbon content, because Cr does not work after combining with C, in order to ensure that enough Cr element is dissolved in the steel to realize the corrosion resistance, the ratio of Cr content to C content should be greater than 14. Therefore, by adjusting the ratio of Cr content to C content, the best anti-corrosion and wear resistance is realized, and the content of chromium element is limited to 1.5-3.5%.

[0049] Sb: Sb element can generate SnO2 and Sb2O5 oxide film on the surface of the steel, inhibit the anodic dissolution of Fe, so as to realize the corrosion resistance; but too high Sb content affects the toughness of the steel, therefore, the content of antimony element is limited to 0.1-0.3%, preferably 0.15-0.25%.

[0050] S: S and Mn are easy to form MnS segregation, which reduces the toughness and corrosion and wear resistance, at the same time, the generated iron sulfide also easily leads to hot brittle, which is an impurity element, but excessive reduction of S element will lead to the increase of cost. Therefore, the content of sulfur element is limited to below 0.005%.

[0051] P: P and Fe, Mn elements produce eutectic sulfide, which is easy to precipitate at the grain boundary, reduces the low temperature toughness of the material; at the same time, also has the effect of promoting the segregation of Fe, C elements, which will have an adverse effect on the mechanical properties and wear resistance of the steel, but excessive reduction of P element will lead to the increase of cost. Therefore, the content of phosphorus element is limited to below 0.003%.

[0052] In an embodiment of the present application, the chemical composition of the corrosion and wear resistant steel plate according to the mass percentage further comprises at least one of: Nb: 0.005-0.05%, V: 0.00-0.05% and Ti: 0.005-0.05%.

[0053] V, Nb, Ti: Vanadium, niobium and titanium elements can generate fine distribution of high hardness carbonitride in the steel, which is dispersedly distributed in the matrix to resist external wear, at the same time, these fine precipitates can also significantly improve the strength of the material by hindering the movement of dislocations, which has a significant help to improve the wear resistance; in addition, the precipitates dispersedly distributed at the grain boundary can also inhibit the growth of austenite grains, produce the effect of refining the grains, which has a significant effect on improving the toughness of the steel; but too high addition of vanadium, niobium and titanium elements not only will lead to the increase of cost, but also will reduce the toughness due to large size of precipitates. Therefore, one or two of vanadium, niobium and titanium elements can be further selected according to actual needs.

[0054] The low-cost corrosion and wear resistant steel plate mentioned in the present application has a hardness of ≥470HV, an impact energy of ≥90J at-40℃, a tensile strength of ≥1400MPa and an elongation of ≥11%.

[0055] Reference Figure 2 The second aspect of the present application refers to a preparation method of a low-cost corrosion and wear resistant steel plate with low temperature toughness, which is used for preparing the low-cost corrosion and wear resistant steel plate with low temperature toughness of the first aspect, the method comprising:

[0056] Step S1 smelting: according to the chemical composition of mass percentage: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S≤0.005%, P≤0.003%, the balance of Fe and inevitable impurities, smelting and pouring to get ingot, control the smelting temperature of 1600-1700℃, use LF refining furnace and RH refining furnace treatment, the tundish water superheat≤20℃, the whole smelting process is protected casting;

[0057] It can be understood that the LF refining furnace is a ladle refining furnace, and the RH refining furnace is a vacuum circulating degassing furnace.

[0058] Step S2 forging: the ingot is heated to 1150-1250℃ and heated and kept, and then homogenized for 1-4h, and then forged, and the forging temperature is controlled to be 1150-1000℃, to obtain a forged blank;

[0059] Preferably, the ingot is heated to 1170-1230℃ and heated and kept. The homogenization time is preferably 2h, the initial forging temperature is 1150℃, and the final forging temperature is 1000℃, to obtain a forged blank.

[0060] Step S3 rolling: the forged blank is heated to 1050-1150℃ and kept, and then recrystallization rolling and non-recrystallization rolling are carried out after the rolling and keeping time is controlled to be 1-4h, the total rolling times of recrystallization rolling and non-recrystallization rolling are controlled to be 6-9 passes, the total deformation amount is≥88%, the final rolling thickness is 8-20mm, to obtain a hot-rolled steel plate, and the hot-rolled steel plate is air-cooled to room temperature;

[0061] In a feasible implementation, the recrystallization rolling temperature is 1050-950℃, the rolling times are 3-4 times, and the single pass reduction rate is≥25%; the non-recrystallization rolling temperature is 900-800℃, the rolling times are 3-5 times, and the single pass reduction rate is≥20%.

[0062] In a feasible implementation, the heating temperature is preferably 1080-1120℃, the keeping time is preferably 2h, the hot-rolling times are preferably 7 times, the recrystallization stage hot-rolling times are preferably 3 times, the non-recrystallization stage hot-rolling times are preferably 4 times, the hot-rolling deformation amount is preferably 90%, and the thickness of the hot-rolled plate is preferably 10mm.

[0063] Step S4 quenching: the hot-rolled steel plate is quenched at 850-950℃ and kept, and then water quenched to room temperature after the quenching keeping time is controlled to be 10-40min, to obtain a quenched steel plate;

[0064] Step S5: tempering the quenched steel plate at 160-240℃, and controlling the tempering time to be 20-50min, and then air cooling to room temperature to obtain the low-cost corrosion and wear resistant steel plate with low-temperature toughness.

[0065] In one possible implementation, the quenching temperature in step S4 is preferably 880-920℃, the holding time is preferably 10-30min, the quenching medium is water, and the temperature after quenching is room temperature.

[0066] In one possible implementation, the tempering temperature in step S5 is preferably 180-220℃, and the tempering time is preferably 30-50min.

[0067] In the present application, the holding time in steps S2-S5 is:

[0068] τ≥0.02×δ[1.25×(C+Si)]

[0069] Wherein, τ is the heating holding time, rolling holding time, quenching holding time or tempering holding time (h), δ is the wall thickness of the product held for τ time (mm), and C and Si are the carbon and silicon contents (%), respectively.

[0070] It can be understood that when τ is the heating holding time, δ is the thickness of the ingot, and C and Si are the carbon and silicon contents (%) in the ingot. When τ is the rolling holding time, δ is the thickness of the forging blank, and C and Si are the carbon and silicon contents (%) in the forging blank. When τ is the quenching holding time, δ is the thickness of the hot-rolled steel plate, and C and Si are the carbon and silicon contents (%) in the hot-rolled steel plate. When τ is the tempering holding time, δ is the thickness of the quenched steel plate, and C and Si are the carbon and silicon contents (%) in the quenched steel plate.

[0071] The preparation method of the corrosion and wear resistant steel plate mentioned in the present application realizes excellent combination of strength and low-temperature toughness by regulating the microstructure through a two-stage rolling + quenching + low-temperature tempering process.

[0072] Examples 1-4

[0073] The chemical composition of the corrosion and wear resistant steel plate in Examples 1-4 is selected from the following ranges: C: 0.1-0.2%, Si: 0.3-0.7%, Mn: 0.3-0.5%, Cu: 0.2-0.5%, Cr: 1.5-3.5%, Sb: 0.1-0.3%, S≤0.005%, P≤0.003%, and the balance being Fe and inevitable impurities.

[0074] In order to study the influence of C content and Cr content on corrosion wear resistance, four groups of compositions are selected for study. Example 1 is a high-carbon low-chromium steel, Example 2 is a high-carbon high-chromium steel, Example 3 is a low-carbon low-chromium steel, and Example 4 is a low-carbon high-chromium steel. The comparative example is a common NM450 steel containing a small amount of Cr element. The chemical composition of the comparative example and the example steel plates is shown in Table 1.

[0075] Table 1

[0076]

[0077] The specific preparation steps of the corrosion wear resistant steel plates of Examples 1-4 are as follows:

[0078] The steel ingot is obtained by melting and casting at 1650℃ according to the chemical composition and content of the above-mentioned corrosion wear resistant steel plate, and the LF and RH refining furnace is treated. The superheat degree of the tundish molten steel is ≤20℃, and the whole process is protected casting. The ingot is heated to 1200℃ for 2h homogenization, and then forged, with an initial forging temperature of 1150℃ and a final forging temperature of 1000℃, to obtain a forged blank. The forged blank is heated to 1100℃ for 2h, and then subjected to recrystallization and non-recrystallization two-stage rolling. The recrystallization stage is rolled 3 times, with an initial rolling temperature of 1050℃ and a final rolling temperature of 950℃, and a single pass reduction of ≥25%. The non-recrystallization stage is rolled 4 times, with an initial rolling temperature of 900℃ and a final rolling temperature of 800℃, and a single pass reduction of ≥20%. The final thickness of the hot-rolled plate is 10mm, and it is air-cooled to room temperature. The hot-rolled plate is quenched to room temperature after being held at 900℃ for 20min. The quenched steel plate is air-cooled to room temperature after being held at 200℃ for 40min, to obtain a corrosion wear resistant steel plate, wherein, Figure 1 Figure 2 is a microstructure diagram of the steel plate of Example 4.

[0079] The corrosion test, wear test and corrosion wear test methods are as follows:

[0080] (I) Corrosion test

[0081] VersaSTAT3F electrochemical workstation is used for electrochemical test of different example steel plates. A three-electrode system is used for electrochemical test, the working electrode is the different example steel plate, the auxiliary electrode is a platinum electrode, and the saturated calomel electrode (SCE) is the reference electrode. The potentiodynamic polarization method is used for research. The electrolyte solution is a 3.5% NaCl solution by mass fraction. The scanning range of the potentiodynamic polarization curve is -300-1000mV (relative to the open circuit potential, EOC), and the scanning rate is 0.3333mV / s. After the test is completed, the polarization curve is analyzed by Cview software.

[0082] (II) Wear test

[0083] The wear test uses a friction and wear tester (MFT5000, Rtec instruments, USA) in a ball-on-plate mode at room temperature in a normal environment. The counter-attrition balls used in the test are made of Al2O3 and have a diameter of 6 mm. During the test, the ceramic balls move linearly on the surface of the sample, the balls exert a load of 30 N on the surface of the sample, the displacement amplitude is 10 mm, the reciprocating frequency is 2 Hz, the wear time is 120 min, the wear direction is the rolling direction of the experimental steel, and the wear amount is measured by a 3D surface profiler provided with the friction and wear tester.

[0084] (III) Corrosion and wear test

[0085] The corrosion and wear test is different from the wear test in that the test conditions are different. The corrosion and wear test is carried out in a deionized water wet environment and a 3.5% NaCl corrosive environment, and the other conditions are the same.

[0086] In the description of the present application, each embodiment focuses on the difference from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0087] Table 2

[0088]

[0089]

[0090] With reference to Table 2, the present application provides a low-cost corrosion and wear resistant steel plate with excellent low-temperature toughness and a preparation method thereof by controlling the content of each element in the steel plate and combining a heat treatment process. The steel plate realizes the characteristics of hardness ≥ 470 HV, impact energy at-40 ℃ ≥ 90 J, tensile strength ≥ 1400 MPa, and elongation ≥ 11%; compared with the traditional NM450 steel, the mechanical properties are improved, the wear resistance is excellent, and the corrosion and wear resistance is excellent, effectively solving the corrosion and wear problems in complex environments such as room temperature or low temperature, dry or wet, high acid or high alkali, etc.; in addition, the heat treatment process of the steel plate of the present application is two-stage hot rolling + quenching + low-temperature tempering, which is low in cost and conducive to popularization, realizes the combination of "high performance + low cost", and can be widely used in wear parts under corrosion conditions such as mining machinery, metallurgical machinery, cement and chemical machinery.

[0091] In the description of the present application, each embodiment focuses on the difference from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0092] In the description of the present application, relative terms such as first and second and the like can be used solely to distinguish one from another without necessarily implying actual relationship or order between or by them. In the description of the present application, the meaning of "a", "an" and "the" is intended to include both singular and plural referents unless otherwise clearly indicated by their context. Moreover, the terms "comprising", "including", or any other similar reference used in the context of describing a process, method, article, or apparatus are intended to cover the process, method, article, or apparatus inclusive of any additional process, method, article, or apparatus that can not be specifically recited. The terms "comprising", "having", "including", or any other similar reference are not intended to exclude any additional process, method, article, or apparatus that can not be specifically recited.

[0093] In the present application, unless otherwise explicitly specified and limited, a first feature is "on" or "under" a second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature is "over", "above" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in horizontal level than the second feature. The first feature is "under", "below" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in horizontal level than the second feature.

[0094] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an embodiment", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples without contradiction.

[0095] Although the embodiments of the present application have been shown and described above, it is to be understood that the above-described embodiments are exemplary, and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate, characterized in that, The chemical composition of the corrosion-resistant and wear-resistant steel plate, by mass percentage, is as follows: C: 0.1~0.2%, Si: 0.3~0.7%, Mn: 0.3~0.5%, Cu: 0.2~0.5%, Cr: 1.5~3.5%, Sb: 0.1~0.3%, S≤0.005% and P≤0.003%, with the balance being Fe and unavoidable impurities; The microstructure of the corrosion-resistant and wear-resistant steel plate includes tempered lath martensite and chromium carbide precipitates, wherein the volume fraction of the tempered lath martensite is ≥99% and the size of the chromium carbide precipitates is ≤100nm. The method for preparing the low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate includes: Step S1 Smelting: The steel ingot is smelted and cast according to the following chemical composition by mass percentage: C: 0.1~0.2%, Si: 0.3~0.7%, Mn: 0.3~0.5%, Cu: 0.2~0.5%, Cr: 1.5~3.5%, Sb: 0.1~0.3%, S≤0.005%, P≤0.003%, with the balance being Fe and unavoidable impurities. The smelting temperature is controlled at 1600~1700℃, and the LF refining furnace and RH refining furnace are used for processing. The superheat of the molten steel in the tundish is ≤20℃. The casting process is carried out under protective conditions throughout the smelting process. Step S2 Forging: The steel ingot is heated to 1150~1250℃ and held at that temperature. After homogenization for 1~4 hours, it is forged. The forging temperature is controlled at 1150~1000℃ to obtain a forging billet. Step S3 Rolling: The forging billet is heated to 1050~1150℃ and held at that temperature. The holding time is controlled to be 1~4h before recrystallization rolling and non-recrystallization rolling. The total number of rolling passes for recrystallization rolling and non-recrystallization rolling is controlled to be 6~9, the total deformation is ≥88%, and the final rolling thickness is 8~20mm to obtain a hot-rolled steel plate. The hot-rolled steel plate is then air-cooled to room temperature. In step S3: the recrystallization rolling temperature is 1050~950℃, the rolling number is 3~4 times, and the single-pass reduction rate is ≥25%; the non-recrystallization rolling temperature is 900~800℃, the rolling number is 3~5 times, and the single-pass reduction rate is ≥20%. Step S4 Quenching: The hot-rolled steel plate is quenched at 850~950℃ and held at that temperature. The quenching and holding time is controlled to be 10~40 minutes. Then, it is water-quenched to room temperature to obtain quenched steel plate. Step S5 Tempering: Temper the quenched steel plate at 160~240℃ and hold it at that temperature. After controlling the tempering holding time to be 20~50 minutes, air cool it to room temperature to obtain the low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate.

2. The low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 1, characterized in that, The Cr and C content is: Cr / C≥14.

3. The low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 1, characterized in that, The chemical composition of the corrosion-resistant wear-resistant steel plate, by mass percentage, also includes at least one of the following: Nb: 0.005~0.05%, V: 0.00~0.05%, and Ti: 0.005~0.05%.

4. The low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 1, characterized in that, The low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate has a hardness ≥470HV, an impact energy of -40℃ ≥90J, a tensile strength ≥1400MPa, and an elongation ≥11%.

5. A method for preparing a low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate, used in the low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate as described in any one of claims 1 to 4, characterized in that, The method includes: Step S1 Smelting: The steel ingot is smelted and cast according to the following chemical composition by mass percentage: C: 0.1~0.2%, Si: 0.3~0.7%, Mn: 0.3~0.5%, Cu: 0.2~0.5%, Cr: 1.5~3.5%, Sb: 0.1~0.3%, S≤0.005%, P≤0.003%, with the balance being Fe and unavoidable impurities. The smelting temperature is controlled at 1600~1700℃, and the LF refining furnace and RH refining furnace are used for processing. The superheat of the molten steel in the tundish is ≤20℃. The casting process is carried out under protective conditions throughout the smelting process. Step S2 Forging: The steel ingot is heated to 1150~1250℃ and held at that temperature. After homogenization for 1~4 hours, it is forged. The forging temperature is controlled at 1150~1000℃ to obtain a forging billet. Step S3 Rolling: The forging billet is heated to 1050~1150℃ and held at that temperature. The holding time is controlled to be 1~4h before recrystallization rolling and non-recrystallization rolling. The total number of rolling passes for recrystallization rolling and non-recrystallization rolling is controlled to be 6~9, the total deformation is ≥88%, and the final rolling thickness is 8~20mm to obtain a hot-rolled steel plate. The hot-rolled steel plate is then air-cooled to room temperature. In step S3: the recrystallization rolling temperature is 1050~950℃, the rolling number is 3~4 times, and the single-pass reduction rate is ≥25%; the non-recrystallization rolling temperature is 900~800℃, the rolling number is 3~5 times, and the single-pass reduction rate is ≥20%. Step S4 Quenching: The hot-rolled steel plate is quenched at 850~950℃ and held at that temperature. The quenching and holding time is controlled to be 10~40 minutes. Then, it is water-quenched to room temperature to obtain quenched steel plate. Step S5 Tempering: Temper the quenched steel plate at 160~240℃ and hold it at that temperature. After controlling the tempering holding time to be 20~50 minutes, air cool it to room temperature to obtain the low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate.

6. The method for preparing a low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 5, characterized in that, The heat preservation time in S2~S5 is: τ≥0.02×δ[1.25×(C+Si)] Where τ is the forging heating and holding time, rolling heating and holding time, quenching heating and holding time, or tempering heating and holding time, in hours; δ is the wall thickness of the heat-insulated product within the corresponding τ time, in mm; and C and Si are the mass percentage contents of carbon and silicon in the heat-insulated product within the τ time, respectively.

7. The method for preparing a low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 5, characterized in that, Step S2: Heat the steel ingot to 1170~1230℃ and keep it at that temperature.

8. The method for preparing a low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 5, characterized in that, Step S3: Heat the forging billet to 1080~1120℃ and hold it at that temperature.

9. The method for preparing a low-temperature toughness, low-cost corrosion-resistant and wear-resistant steel plate according to claim 5, characterized in that, Step S4: Quench the hot-rolled steel plate at 880~920℃ and hold it at that temperature, and control the quenching and holding time to be 10~30min before water quenching to room temperature to obtain a quenched steel plate; Step S5: Temper the quenched steel plate at 180~220℃ and hold it at that temperature, and control the tempering and holding time to be 30~50min before air cooling to room temperature to obtain a low-cost corrosion-resistant and wear-resistant steel plate with low-temperature toughness.

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