CN113388787A

CN113388787A - High-toughness wear-resistant steel and preparation method for nano twin crystal enhanced toughening of high-toughness wear-resistant steel

Info

Publication number: CN113388787A
Application number: CN202110715404.9A
Authority: CN
Inventors: 不公告发明人
Original assignee: Shanghai Jiaotong University Xuzhou New Material Research Institute Co ltd
Current assignee: Shanghai Jiaotong University Xuzhou New Material Research Institute Co ltd
Priority date: 2021-06-27
Filing date: 2021-06-27
Publication date: 2021-09-14
Anticipated expiration: 2041-06-27
Also published as: CN113388787B

Abstract

The invention relates to high-toughness wear-resistant steel and a preparation method for nano twin crystal enhanced toughening thereof, wherein the preparation method comprises the following components in percentage by mass: 0.35-0.85% of C, 15.2-24.8% of Mn, 0.1-0.5% of Si, less than or equal to 1.0% of Al, less than or equal to 0.005% of S, less than or equal to 0.01% of P, 0.5-1.5% of Nb, 0.2-0.8% of Ti, 0.2-0.75% of V, 0.005-0.05% of N, rare earth RE: 0.02-0.1 percent, and the balance of Fe and inevitable impurities. The alloy has a stacking fault energy of 24-30 kJ/m²The mass percentages of the added Ti, Nb and V satisfy: 2:1:1. The preparation process comprises alloy smelting and negative pressure casting, homogenization heat treatment and cogging, hot rolling, nanometer twin biochemical treatment, nanometer twin crystal stabilization and low-temperature aging treatment. The invention relies on the optimized matching design of low-layer fault energy and microalloying components, and carries out refined structure regulation and control based on deformation and heat treatment means, thereby realizing good matching of structures, and the alloy has high strength, high toughness and high wear resistance. The wear-resistant steel has excellent comprehensive mechanical property, low alloy cost, simple preparation process and low production and manufacturing cost, and is easy to be put into industrial production and large-scale industrial equipment.

Description

High-toughness wear-resistant steel and preparation method for nano twin crystal enhanced toughening of high-toughness wear-resistant steel

Technical Field

The invention relates to the technical field of wear-resistant steel and processing and preparation thereof, in particular to high-toughness wear-resistant steel and a preparation method of nano twin crystal enhanced toughening of the high-toughness wear-resistant steel.

Background

The steel materials are still the most important engineering materials with the strongest adaptability and universality, and the abundant equipment experience, the low production cost and the wide performance plasticity space are all incomparable with other materials in a short time. In recent years, steel materials are more applied to the key fields of aerospace, national defense and military industry, novel transportation technology and the like, the steel industry is integrally developed towards the direction of green, environmental protection, energy conservation and emission reduction, and requirements are provided for further improving the comprehensive mechanical property of steel. The manganese alloy wear-resistant steel is a common high-performance steel material, has good wear resistance, strength, plasticity and corrosion resistance, is widely applied to important fields of heavy-duty equipment, mining machinery, advanced equipment, aerospace military industry, transportation and the like, and occupies an important position in steel material equipment. Generally, high manganese alloy steels are superior to those having a stable austenitic structure, and have relatively low strength hardness, and despite excellent work hardening capability, wear resistance is still to be improved. With the development and continuous progress of industry, higher requirements are put on high strength and high toughness of wear resistance.

Dislocation and twinning are two main deformation mechanisms of metal materials, and generally, when the material stacking fault energy is low, the stacking fault density is high, dislocation slippage is hindered, and twinning is more likely to occur during material deformation. Twin boundary generated by twin crystal has strengthening and toughening effect on the mechanical property of the material. Since the Frommeyer et al 1997-1998 put forward the TWIP effect of the multi-manganese alloy steel for the first time and developed TWIP steel, high-strength, high-toughness and high-manganese alloy steel taking twinning as the main strengthening mechanism has been attracting attention. The great improvement of the strength (especially the yield strength) of the manganese alloy steel while maintaining the equivalent plasticity becomes the main optimization direction of the material performance. In addition, the production cost and the process flow of the selected preparation mode are also important considerations for large-scale industrial application.

Three main ideas are provided in the current industry for improving the strength of the twin high-manganese alloy wear-resistant steel. The first is a pre-strain treatment. Studies have reported that the yield strength of twin high manganese alloy steels can be considerably increased by both pre-rolling and pre-drawing, but also the elongation of the material is significantly reduced. It was found that the yield strength can be made to exceed 1000MPa by 10% rolling treatment (see documents steel 2011,46(11): 77-81). While the study of Bouaziz et al, after 20% re-rolling treatment, can increase the yield strength of Fe-22Mn-0.6C TWIP steel from 600MPa to over 1400MPa, but the elongation is significantly reduced to 4% (see the script materials, 2010,62(9): 713-715). The second is fine grain strengthening. According to the Hall-Petch formula, the refinement of the grains can obviously improve the strength of the material, and in most cases, the fine grain strengthening can lose equivalent elongation to a certain extent. The requirement of the automobile industry for the yield stress of the material is not satisfied by the fine grain strengthening alone, for example, Fe-22Mn-0.6C steel, in order to achieve 600-700 MPa required by the automobile industry, the grain needs to be refined to 1 μm, however, the large production line of industrial rolling can only achieve the minimum level of 2.0 μm (see the literature, Current Opinion in Solid State & Materials Science,2011,15(4): 141-. The third mode is second phase (precipitation) strengthening. It is found that Ti, V and Nb have certain strengthening effect on the material, but the strengthening upper limit of the Ti and the V is stronger than that of the Ti, wherein the strengthening contribution of V can reach 400MPa, and the Ti is near 150 MPa. Studies have shown that V can increase the tensile strength and yield strength of the material, but can reduce the elongation. All precipitates precipitated as above have a stable temperature range between 450 ℃ and 700 ℃. But compared with the traditional Nb, V and Ti microalloyed HSLA steel, the amount of the alloying elements added into the microalloyed TWIP steel is increased by at least one order of magnitude (see the literature, Nb and Ti alloyed low-carbon high-strength high-plasticity TWIP steel and a preparation method [ M ]. CN.2012). In addition, a series of new methods such as surface coating are also in the laboratory research stage. Aiming at the characteristic of low-layer fault energy of the manganese alloy steel, a lifting route for improving the twin crystal density in the material by low-temperature rolling has not been widely practiced and applied.

In the prior art, the manganese alloy wear-resistant steel with improved comprehensive mechanical properties by a traditional treatment mode usually has a certain improvement space in the aspects of strengthening effect and processing technology feasibility. For example, patent CN105200309A discloses a heat treatment method for improving high manganese steel material, which can obtain a mixed structure of coarse grains (grain size greater than about 5 microns) and ultra-fine grains (size less than 1 micron) by annealing treatment, so that the grain boundary strengthening effect is sharply enhanced, but the yield strength of the material is improved by no more than 400MPa, which still is difficult to meet the application requirements in the heavy-duty wear-resistant field. Patent CN107858602A discloses a high-toughness austenitic high manganese steel sheet and a production method thereof, which comprises the steps of rolling and heat treatment, but the strengthening effect is not obvious due to insufficient deformation and over high rolling temperature. Patent CN104962825A discloses a preparation method of an ultrahigh manganese multi-element rare earth wear-resistant alloy steel lining plate, which mainly aims at improving the wear resistance of materials, but the yield strength of the lining plate is about 600MPa, the lining plate cannot meet the use scene of high-strength steel with high wear resistance, and the used steel contains more rare earth elements and the production equipment cost is high.

The tissue refinement is an effective means for improving the strength and toughness of the material. The improvement of the strength and the plasticity of the material simultaneously is a main target of related researches on the performance improvement of the structural material for a long time, and the researches show that the uniform and refined microstructure obtained by the heat treatment after the strong deformation is a reliable scheme which is widely practiced and accepted in academia and industrial production. But compared with the traditional strong deformation mode, such as channel corner extrusion, high-pressure torsion and other strong plastic deformation means, the strong deformation rolling has the irreplaceable advantages of low production cost, more production equipment resources, easiness in preparing large block materials and the like. However, it is difficult to obtain a large number of high-angle grain boundaries only by means of strong deformation rolling, and the low-angle grain boundaries obtained by the strong deformation rolling have a limited effect on improving the plasticity of the material. Suitable heat treatment processes are generally required to achieve a high level of high angle grain boundaries in the strongly deformed material, thereby achieving a high level of overall mechanical properties. (see the literature Progress in Materials Science,94(2018)462- & 540; 45(2000)103- & 189.)

Compared with the conventional high-angle grain boundary, the twin crystal interface has better effect on improving the strength and plasticity of the material. As a highly coherent interface, the interface storage energy of the twin boundary is one order of magnitude lower than that of the high angle boundary. On one hand, the nanometer twin crystal boundary can divide the original crystal grains into a plurality of areas to play a role in fine crystal strengthening. If a high-density nanometer twin crystal interface can be further introduced into a fine-grained or ultra-fine-grained structure, the strength and the toughness of the material can be obviously improved. However, the method of introducing high-density twin crystal is usually to introduce annealing twin crystal for heat treatment, but the method is superior to the method in which crystal grains grow during annealing, and the twin crystal size is relatively large, so that the effects of high strength and high toughness are difficult to achieve. Aiming at high manganese alloy wear-resistant steel, if the composition design is adopted, alloy with certain relative low-layer fault energy can be obtained, the austenite is stable enough, high-density nano-deformation twin crystals are induced through deformation at room temperature or ultralow temperature, a high-density twin crystal interface is introduced, the material strength is obviously increased, and meanwhile, the matrix structure is still austenite, so that the high-manganese alloy wear-resistant steel has good ductility and toughness. In addition, if a high-density nano precipitated phase can be prepared in the alloy design and the preparation process thereof and matched with a nano twin boundary, the strength of the material can be further remarkably improved. The twin crystal has strong capability of blocking dislocation movement and dislocation absorption, and can simultaneously strengthen the strength and plasticity of the material. This provides a theoretical basis for preparing high-performance wear-resistant metal materials. At present, the principle of introducing high-density nanometer twin crystals and nanometer precipitation by virtue of thermomechanical treatment is still rarely reported to prepare high-toughness wear-resistant alloy.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provide the bottom-layer fault energy alloy steel based on component optimization design, and provide a preparation process method for preparing the wear-resistant steel which is mainly prepared from high-density nano twin crystals and nano composite precipitated phases and has high strength and high toughness.

The purpose of the invention can be realized by the following technical scheme:

the high-strength and high-toughness wear-resistant steel is optimally designed by alloy, and comprises the following chemical components in percentage by mass: 0.35-0.85% of C, 15.2-24.8% of Mn, 0.1-0.5% of Si, less than or equal to 1.0% of Al, less than or equal to 0.005% of S, less than or equal to 0.01% of P, 0.5-1.5% of Nb, 0.2-0.8% of Ti, 0.2-0.75% of V, 0.005-0.05% of N, rare earth RE: 0.02-0.5 percent, and the balance of Fe and inevitable impurities.

The alloy fault energy of the high-strength and high-toughness wear-resistant steel is 24-30 kJ/m²The mass percentage of the Nb, Ti and V added in the alloy under the optimized condition meets the following requirements: 2:1:1, and researches show that under the condition of the proportion, the precipitation of Nb, Ti and V is mainly the precipitation of composite carbonitride of two or three elements, the size is fine, and the appearance is equiaxed granular or spherical.

The preferable alloy system of the high-strength high-toughness wear-resistant steel comprises the following components in percentage by mass: 0.5-0.8% of C, 20-24% of Mn, 0.1-0.5% of Si, less than or equal to 1.0% of Al, less than or equal to 0.005% of S, less than or equal to 0.01% of P, 0.6-1.0% of Nb, 0.3-0.5% of Ti, 0.3-0.5% of V, 0.01-0.02% of N, and rare earth RE: 0.02-0.5%, and the balance of Fe and inevitable impurities.

The high-strength and high-toughness wear-resistant steel further preferably comprises the following components in percentage by mass: 0.5 percent of C, 20 plus or minus 0.5 percent of Mn, 0.25 percent of Si, less than or equal to 1.0 percent of Al, 1.0 plus or minus 0.2 percent of Nb, 0.5 plus or minus 0.1 percent of Ti, 0.5 plus or minus 0.1 percent of V, 0.01 percent of N, rare earth RE: 0.05 +/-0.01%, and the balance of Fe and inevitable impurities.

The key points of the design of the alloy components in the invention are as follows:

the alloy has a stable face-centered cubic single-phase austenite structure, and the alloy stacking fault energy is 24-30 kJ/m²In this range of stacking fault energy, the alloy deforms at room temperature or below, and dislocation slip is difficult during deformation, and twinning is likely to occur. The method can realize a deformation mode with twinning as the main part and dislocation slippage as the auxiliary part, and can realize tissue twinning through reasonable processing deformation process and tissue regulation. In general, the density of twin crystals is closely related to the deformation rate and the deformation temperature in addition to the stacking fault energy of the material, so that the composition design of the wear-resistant steel fully considers the stacking fault energy, the transformation temperature and other factors beneficial to the subsequent processing technology.

The material adopts the composition combination design of medium carbon content plus micro-content nitrogen, high manganese, low silicon, low aluminum, niobium vanadium titanium low alloying matching, and is technically characterized in that: the addition of Nb, Ti, V and the like into the gold component can induce a nano precipitated phase in the high-temperature hot rolling process, the high-temperature dynamic recovery and recrystallization can inhibit the growth of crystal grains, and the effect of inhibiting the growth of the crystal grains can also be achieved in reheating treatment after hot rolling and reheating after cold deformation; the design of medium-high carbon, micro nitrogen and high manganese content mainly adjusts the stacking fault energy of the alloy within the design range in a matching way on one hand, and provides guarantee for the subsequent nanometer twin crystallization. On the other hand, a certain amount of carbide is ensured to be precipitated, so that the matrix is toughened, meanwhile, a large amount of precipitated carbide plays roles in precipitation strengthening and nanometer twin crystal stabilization, the material is ensured to have enough carbide precipitation, has enough strength and hardness, keeps certain toughness, improves the wear resistance and prolongs the service life.

Specifically, the alloy composition in the invention has the following characteristics:

(1) the content of C is 0.35-0.85 wt%

Due to the use requirements of high strength and high wear resistance, the content of C element in the alloy is 0.35-0.85 wt%. The carbon content range is matched with the system of micro nitrogen and high manganese in the invention, and the alloy stacking fault energy can be controlled to be 24-30 kJ/m²Is favorable for realizing the purpose of nano twin crystallization. More importantly, the addition of carbon helps to promote the material baseThe strength of the body, the reasonable heat treatment can form iron carbide, and the nano precipitated phase formed by the iron carbide and a proper amount of Nb, Ti and V can further strengthen the alloy and stabilize the nano deformation twin crystal to a higher temperature in the recovery heat treatment process. According to the alloy fault energy, the C content is not suitable to be too low, because the TRIP effect is easy to occur in the deformation process due to the too low C content, the alpha' or epsilon martensite is induced to form, the plasticity of the steel is influenced, and the purpose of realizing high-density nano twin crystallization cannot be achieved. Meanwhile, the alloy is not easy to be too high, the casting performance is influenced, and the weldability is reduced. The content of C in the component system of the present invention is preferably in the range of 0.5 to 0.8 wt%, and more preferably in the range of 0.5 wt%. The proportion of carbide can be effectively increased by selecting the content, the hardness of the matrix is improved, and the wear resistance is better. Research shows that higher carbon content is unfavorable for toughness, carbide is obviously increased, precipitation amount of cementite is increased, and carbide coarsening is serious and is distributed on grain boundaries, so that the toughness of the material is reduced. In the alloy system of the present invention with carbon content, the wear mechanism was found to be a combination of adhesion and abrasive wear. The invention relates to a relative high-carbon manganese alloy steel, which obviously refines austenite structure by combining a modification refiner with a controlled casting process or a subsequent low-temperature deformation and heat treatment process, and uniformly distributes carbon or nitride precipitated by a regulating and controlling process, so that the prepared material still has relatively good toughness and plasticity indexes under the condition of ensuring that the strength is not obviously reduced, and the wear resistance and the service life of the material are improved.

(2) The Mn content is 15.2-24.8 wt%

Manganese is an austenite area enlarging element and is also an important alloy element in wear-resistant steel. Too high a manganese content may cause a decrease in alloy hardness and deterioration in casting properties. In the invention, the high manganese alloy content range and the carbon are mutually matched to effectively control the stacking fault energy, so that nanoscale deformation twin crystals can be introduced through deformation rolling, and then the nanoscale twin crystals are stabilized through recovery treatment. Therefore, in the range of the carbon content in the invention, the optimized alloy range is 15.2-24.8 wt%. The upper limit of the Mn content in the high-strength wear-resistant manganese steel is 24.8 wt%. In the traditional multi-manganese wear-resistant steel, the content of Mn is higher than 15 wt%, otherwise, the generation of epsilon martensite is induced in the deformation process, and the TRIP effect is generated. In the present invention, it was found that when the Mn content is less than 15.2 wt%, although the tensile strength is improved, the yield strength is slightly decreased while the plasticity is remarkably decreased, and at the same time, the TRIP effect during a large amount of deformation occurs. Therefore, the lower limit of the Mn content suitable for the present invention is 15.2 wt%, and the preferable composition thereof is 20. + -. 0.5 wt%. The manganese content and the material of the invention have excellent work hardening capacity, which is directly related to the designed alloy having excellent austenite stabilization and forming an ultrafine nanometer twin crystal structure.

(3) Al and Si contents of not more than 1.0 percent and not more than 0.1 and not more than 0.5 percent

In order to avoid the adverse effect of high Al in the conventional wear-resistant steel, the contents of Al and Si in the composition system of the present invention are controlled to be low. The appropriate Al content can well adjust the stacking fault energy, inhibit the generation of epsilon martensite and improve the toughness of the material. However, too high Al content deteriorates castability and weldability of the material. Considering the Mn content of the material in the present invention, the preferable composition of Al is determined to be 1.0% or less. Si is a replacement element and can play a good role in solid solution strengthening in the multi-manganese alloy steel. In the present invention, it is found through experiments that if the Si content is less than 0.1 wt%, the effect of solid solution strengthening is not significant, and if the Si content is too high, the surface property is also liable to cause welding defects, so the Si content in the present invention is determined to be not more than 0.5%.

(4) N content N: 0.005-0.05%

The N element has good solid solution strengthening and corrosion resistance effects, is matched with Nb, Ti and V, forms a nitride precipitated phase in a matrix, has strong high-temperature thermal stability and strengthening effect, and can be used as supplement for strengthening the nano twin crystal material. In consideration of the use requirement of the material on high toughness, the content of N in the invention is determined to be 0.005-0.05%. However, adding too much N to high manganese alloy steel causes a significant decrease in N liberation and plasticity. In the alloy system of the invention, the optimal adding amount of N is determined to be 0.01 wt%.

(5) The composition of P and S is as follows: p is less than or equal to 0.01wt percent, S is less than or equal to 0.005wt percent

The steel grade contains a proper amount of P, which is beneficial to improving the machining and cutting performance, and is also beneficial to strengthening the matrix and promoting the twinning in austenite. However, P is likely to be segregated in the grain boundary to cause brittleness of steel, so that the content of P in the present invention should not exceed P.ltoreq.0.01 wt%. S is easy to form sulfides in the process of billet solidification, and particularly in high Mn steel, MnS is easy to form, cracks are easy to generate, and the mechanical property is not favorable, so that the content of P in the invention is not more than 0.005 wt% of S. In the preferred composition, the incorporation of the next two elements should be avoided as much as possible.

(6) Rare earth RE:0.02 to 0.1 percent

The main function of the rare earth in the invention is modification treatment. Due to the addition of the rare earth alterant, the multi-manganese alloy steel can obviously improve the strength without obviously reducing the plasticity and the toughness. Meanwhile, the RE element has a certain grain refining effect, and can improve the grain boundary strength. The RE content in the invention is determined to be 0.02-0.5%. The rare earth resource is abundant in China, and the component design in the invention is based on the national situation. However, because the grain boundary can be embrittled by excessive RE, trace rare earth elements are generally added into medium carbon steel, so that the quality of a casting blank can be obviously optimized, and a good using effect is obtained. In the present invention, the preferable content of RE is controlled to 0.05. + -. 0.01%.

(7) Nb, Ti and V in an amount of 0.5 to 1.5%, Ti in an amount of 0.2 to 0.8% and V in an amount of 0.2 to 0.75%

The addition of Nb can refine austenite grains after recovery recrystallization mainly by controlling the precipitation of Nb-containing nitrides or carbonitrides, suppressing coarsening of the structure by pinning of the precipitated phase particles to grain boundaries and solute dragging of solid-solution Nb atoms, and strengthening the structure by precipitation. The addition of Ti and V mainly considers the carbonitride of Ti and V formed at high temperature or the combination of the carbonitride and Nb to form Nb, Ti and V composite carbonitride, thereby inhibiting the growth of crystal grains and forming precipitation strengthening at the same time of refining the crystal grains. In addition, the formed carbonitride precipitated phase of Ti has excellent high-temperature stability, and can effectively improve the welding performance. Meanwhile, the addition of the three trace elements is not suitable to be excessive, otherwise, the material performance is reduced, and the coarsening of the second phase particles is mainly related. According to the comprehensive experiment result, the contents of the trace elements of the three are controlled to be 0.5-1.5% of Nb, 0.2-0.8% of Ti and 0.2-0.75% of V. Compared with the traditional Ti, Nb and V microalloying, the addition amount in the research is basically one order of magnitude higher, but still belongs to the category of trace addition. This is mainly because the high manganese content alloy causes an increase in the activity limit of the precipitated carbonitrides and an increase in the solubility of the high amount of the three elements in the alloy, so that the addition amount is relatively increased, but the addition of medium-high carbon, i.e., the matching, ensures that Ti, Nb, and V can be completely precipitated in the heat treatment after the hot rolling and the subsequent room-temperature, i.e., low-temperature rolling, and ensures that a good effect is obtained.

The invention is obtained through experimental analysis, and the precipitated phases of Ti, Nb and V can be precipitated near the twin crystal interface, thereby effectively improving the mechanical stability and the thermal stability of the twin crystal. Meanwhile, the addition of the trace elements can effectively improve the deformation resistance of the material at the initial stage of tensile deformation, effectively improve the yield strength of the manganese-rich alloy steel and not obviously influence the plasticity of the material. In the invention, the preferable mass percentages of the addition amounts of Ti, Nb and V satisfy: 2:1:1. The reason is mainly because experiments show that when the total mole fraction of the added Nb and V is close to the Ti content, the shape of the formed composite precipitated phase particles is mostly close to spherical or ellipsoidal, which is beneficial to reducing the influence on the plasticity of the material. Otherwise, the precipitation compatibility is easy to be close to square, and the plasticity is obviously reduced. Experiments also show that the precipitated phase is distributed most uniformly and has the best strengthening effect when the total amount of the Nb precipitated phase and the V precipitated phase is 1: 1.

The invention aims at the wear-resistant alloy of a designed component system, and also relates to a nanometer twin crystal strengthening and toughening preparation process for the wear-resistant alloy steel, which comprises the process steps of alloy smelting and negative pressure casting, homogenization heat treatment and cogging, hot rolling, nanometer twin biochemical treatment, nanometer twin crystal stabilization, low-temperature aging treatment and the like, and the specific steps comprise:

(1) alloy smelting and negative pressure casting: uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) homogenizing heat treatment and cogging: carrying out high-temperature homogenization treatment on the cast ingot obtained in the step (1) at 1200-1280 ℃, keeping the temperature for 2.0-5.0 h, air-cooling to 1100 ℃, forging or rolling and cogging, wherein the finish forging or finish rolling temperature is not lower than 950 ℃, the thickness of the material after cogging is not less than 60mm, and cooling to room temperature by water;

(3) hot rolling: heating the plate treated in the step (2) to 900-950 ℃, preserving heat for 2.0-5.0 h, then carrying out hot rolling, wherein the initial rolling temperature is not lower than 800 ℃, the final rolling temperature is not lower than 700 ℃, obtaining a plate with the final rolling thickness of 10-30 mm, and carrying out air cooling to room temperature after rolling;

(4) nano twin biochemical treatment: reheating the alloy material treated in the step (3) to 830-900 ℃, preserving heat for 0.5-1.0 h, air-cooling to room temperature, then cold-rolling at room temperature or ultralow temperature, wherein the total rolling deformation is not more than 80%,

(5) nano twin crystal stabilization and low-temperature aging treatment: and (3) heating the material treated in the step (4) to 400-450 ℃ for dislocation recovery treatment, keeping the temperature for 1.0-2.0 h, and then carrying out low-temperature aging treatment, wherein the aging temperature is 200-400 ℃, and the keeping temperature for 5.0-8.0 h, so as to obtain the high-density nano deformation twin crystal and nano precipitated phase reinforced high-strength and high-toughness wear-resistant steel.

According to the preparation method for the high-strength and high-toughness wear-resistant steel and the nano twin crystal reinforced toughening of the high-strength and high-toughness wear-resistant steel, the smelting mode adopted in the step (1) is vacuum induction and is combined with any one or two of electric arc furnace smelting, electric slag remelting, vacuum smelting and vacuum self-consumption, negative pressure casting is carried out to form a plastic film sealing sand box, and air in the mould is pumped out by a vacuum pumping system; in the step (2), the homogenization temperature is 1250 ℃, the heat preservation is 2.0h, the initial rolling temperature is 1100 ℃, the final rolling temperature is 950 ℃, and the cogging thickness is 60 mm.

According to the preparation method for the high-strength and high-toughness wear-resistant steel and the nano twin crystal reinforced toughening of the high-strength and high-toughness wear-resistant steel, the material in the hot rolling process in the step (3) is heated at 950 ℃, is subjected to hot rolling after being kept for 2.0-5.0 h, the initial rolling temperature is 800-850 ℃, the final rolling temperature is 700-750 ℃, a plate with the final rolling thickness of 10-20 mm is obtained, and the plate is air-cooled to room temperature after being rolled;

the preparation method for strengthening and toughening the high-strength and high-toughness wear-resistant steel and the nanometer twin crystal thereof is characterized by comprising the following steps of: the nanometer twin biochemical treatment process in the step (4) can also comprise a first-stage cold rolling and a second-stage ultralow temperature rolling twin biochemical treatment process:

first-stage treatment: reheating the material treated in the step (3) to 800-900 ℃, preserving heat for 0.5-1.0 h, then air-cooling to room temperature, then cold-rolling until the deformation is not more than 50%, then carrying out recovery treatment, heating to 500-600 ℃, preserving heat for 0.5-1.0 h, and then air-cooling to room temperature to realize primary deformation twin crystallization of the material structure and recovery of the dislocation structure; secondary nano twinning treatment: and (3) rolling the material subjected to the primary treatment at an ultralow temperature, wherein the rolling temperature of the ultralow-temperature material is lower than-60 ℃, and the accumulated deformation is 25-40%.

According to the preparation method for the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening thereof, the nano twin treatment in the step (4) comprises two-stage treatment, wherein the room-temperature rolling deformation of the one-stage twin treatment is 40%, and the temperature of the recovery treatment is 500 ℃ and is kept for 1 h; the ultra-low temperature rolling of the second-stage twinning treatment is that the temperature is kept for 1.0 hour at the temperature of liquid nitrogen, and the accumulated deformation is 30 percent.

According to the preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening of the high-strength and high-toughness wear-resistant steel, the nano twin crystal stabilizing treatment in the step (5) is one-step treatment, the temperature is increased to 400 ℃, the heat preservation time is 6 hours, the treated tissue is that the average width of high-density nano twin crystals is less than 50 nanometers, and the nano precipitated phase after aging treatment is not more than 15 nanometers.

The preparation method for the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening of the high-strength and high-toughness wear-resistant steel comprises the twin treatment in the step (4), a multi-pass small-deformation asynchronous rolling process is adopted, the differential speed ratio of asynchronous rolling is 1.1-2.0, and the asynchronous rolling comprises any one of the following modes: namely, the two working rolls have the same diameter but different rotating speeds, the rolls have different diameters but the same rotating speeds or the roll diameters and the rotating speeds are different, the microstructure of the obtained plate is an ultrafine crystal austenite single-phase structure, and the crystal is rich in high-density distorted annealing twin crystals and nano-scale deformation twin crystals with different orientations.

The preparation method for strengthening and toughening the high-toughness wear-resistant steel and the nanometer twin crystal thereof has the further optimized process that the secondary twin biochemical treatment temperature in the step (4) is-60 to-100 ℃, and the rolling total deformation is 30 to 40 percent.

According to the high-strength and high-toughness wear-resistant steel and the preparation method of the nano twin crystal reinforced toughening steel, in the step (4), the rolling temperature is room-temperature rolling, and the total rolling deformation is 50%.

The high-strength and high-toughness wear-resistant steel and the preparation method of the nanometer twin crystal reinforced toughening steel have the advantages that in the step (4), the rolling temperature is-80 ℃, and the deformation is 75%.

The high-strength and high-toughness wear-resistant steel and the preparation method of the nano twin crystal enhanced toughening of the high-strength and high-toughness wear-resistant steel have the advantages that the structure of the prepared high-strength and high-toughness wear-resistant steel material is single-phase ultrafine crystal austenite, the interior of the high-strength and high-density nano twin crystal enhanced nano precipitated phase is contained, the width of the nano twin crystal is less than 20 nanometers, the precipitated phase is less than 10 nanometers, the yield strength is not lower than 1500MPa, and the tensile strength exceeds 2000 MPa.

According to the high-strength and high-toughness wear-resistant steel and the preparation method of the nano twin crystal reinforced toughening of the high-strength and high-toughness wear-resistant steel, the thickness of the high-stability high-density nano twin crystal reinforced high-strength and high-toughness wear-resistant steel obtained after the low-temperature aging treatment in the step (5) is not less than 3 mm.

The key of the above process technology lies in regulating the organization of the material, and the organization finally determines the performance of the material. The invention has the organization and design ideas as follows:

in the research, the hot rolling is carried out, then medium-temperature short-time heating recovery and recrystallization treatment are carried out again, so that the equiaxial transformation of the hot rolling deformation material crystal grains is realized, and the crystal grain recovery recrystallization is not remarkably long. The addition of carbon and nitrogen elements also controls the stacking fault energy, dislocation movement and dynamic recovery of the alloy, and is easy to regulate and control. In the alloy, the recovery heat treatment process is carried out after cold rolling and after ultralow temperature rolling. The dislocation density is obviously reduced, and by introducing a large amount of deformed twin crystals, a coherent twin crystal interface with low layer dislocation energy can play a good role in strengthening the crystal boundary, and simultaneously toughens the material, so that a foundation is laid for the subsequent cold deformation and ultralow temperature deformation induced nano deformation twin crystals and the subsequent recovery twin crystal stabilization treatment.

Single phase nano twinned strengthened austenite and nano precipitated phase strengthening are combined. Austenite has excellent work-hardening ability, and generally, coarse austenite has relatively low strength and hardness. It is well known that tissue refinement is an effective means to improve both strength and plasticity. Compared with the common hot rolling process, the hot rolling temperature of the invention is relatively low, the finishing temperature is even only 700 ℃, the process is mainly selected based on the optimally designed alloy components, the material can keep a stable austenite structure, and the material can not deform to induce martensite transformation even below room temperature. The heat treatment method of heating to high temperature and keeping the temperature for a short time after hot rolling, which is the structure with primary refinement, shows that the rolling process and the subsequent heat treatment of the invention can enable austenite grains to be primarily refined to 5-10 microns, the grains are equiaxed grains, and a certain amount of annealing twin crystals are contained. The grains are obviously refined through the hot rolling at the relatively low temperature, mainly because the titanium and niobium which are completely dissolved at the high temperature are dynamically induced to be separated out in the hot rolling process, and because the relative temperature is lower, the carbon-nitrogen composite separation which is mainly separated out and is mainly in the nano scale is realized. And the subsequent heat treatment process step is matched to play a role in obviously inhibiting the growth of crystal grains, so that the aim of refining the structure through process control is fulfilled. In the invention, austenite grain refinement is realized through rolling and processing, and deep deformation processing is carried out at room temperature or low temperature, which is mainly that for the alloy with energy failure with the bottom layer, the lower temperature is favorable for twin proceeding, and dislocation is inhibited. By introducing deformation twin crystal and stabilizing treatment, austenite nano twin crystal is mainly used, the structure is further refined, and simultaneously, a high-density twin crystal interface is introduced, so that the material is strengthened. More importantly, a large amount of nano-scale precipitated phases can be induced in the heat recovery treatment stage after hot rolling and cold rolling, and the strength, hardness and wear resistance of the material are further improved while the matrix is toughened.

The medium-low carbon austenitic manganese alloy wear-resistant steel adopts the processes of alloy smelting, homogenization heat treatment and cogging, hot rolling pretreatment, intermediate tempering treatment, primary low-temperature rolling treatment, secondary low-temperature rolling treatment, low-temperature aging treatment and the like, and introduces high-density multi-scale annealing twin crystals and nano twin crystals into the material while refining the austenitic grain structure in the alloy. The twin crystal interface is used for further dividing the internal area of the crystal grains, and the effect of ultra-fine crystal strengthening is realized. Meanwhile, the activation energy of the twin crystal interface is lower than that of a common high-angle crystal boundary, the interface presents a more stable state, and the interface also has strong capabilities of absorbing and decomposing dislocation, so that the material prepared by the invention has high strength and high hardness and good plasticity and toughness, a large amount of nano precipitated phases are matched with nano twin crystals through process control, and the alloy presents excellent wear resistance.

Compared with the prior art, the invention has the following advantages:

(1) the high-performance wear-resistant steel has high cost performance. The developed alloy does not contain noble metal elements such as nickel, chromium, molybdenum and the like, only mainly comprises iron and manganese with low cost, and can obtain the performance effects of high strength, high toughness and high wear resistance by trace low-cost carbon and nitrogen, microalloyed niobium, titanium and vanadium and conventional hot working, cold working and heat treatment processes. The wear-resistant steel plate prepared by the low-cost alloy component design and the method has a fine microstructure, the structure is an ultrafine austenite matrix, the austenite grains contain high-density and high-stability nano twin crystals and a certain dispersion distribution of nano precipitated phases, and the material with the process structural characteristics has excellent comprehensive mechanical properties. The high-strength and high-toughness wear-resistant steel material prepared by the preferred process has the structure of single-phase ultrafine grain austenite, the interior of the material contains high-stability and high-density nano twin crystal strengthening and nano precipitated phases, the width of the nano twin crystal is less than 20 nm, the precipitated phase is less than 10nm, the yield strength is not lower than 1500MPa, and the tensile strength exceeds 2000 MPa.

(2) The low-layer fault energy alloy and the core process in the preparation method of the invention are as follows: the combination of low-temperature rolling and low-temperature tempering treatment processes can realize the nano twin crystal stabilization of the low-layer fault energy alloy matrix material, and simultaneously introduce a high-density nano precipitated phase, the process has the effect of strengthening and toughening, which cannot be achieved by the conventional process, and the method has certain superiority. As is known, dislocation slip and twinning are two competing deformation mechanisms, in normal temperature rolling, a dislocation slip system is more active in a lower temperature environment, the work hardening of a material is serious, on one hand, the strong deformation process is not facilitated to implement, and on the other hand, a great amount of dislocation generation can damage deformed twin crystals and annealed twin crystals prepared by preorder deformation. And the dislocation multiplication and slippage are inhibited by rolling at low temperature, thereby being beneficial to improving the deformation and preparing high-density twin crystals. And the two-stage low-temperature rolling with mutually vertical rolling directions is also used for further improving the deformation, and other twin systems are started as much as possible on the premise that the twin system at one stage is saturated. In addition, the precipitation of a precipitated phase in the alloy steel can be promoted by the subsequent low-temperature tempering process, the precipitation of the precipitated phase near a twin crystal interface can play a pinning effect on twin crystals, the thermal stability of the twin crystals is facilitated, and meanwhile, the low-temperature aging tempering can repair or newly generate a part of annealing twin crystals on the premise of not damaging the existing twin crystal structure. The technological parameters of low-temperature rolling and low-temperature tempering adopted in the preparation method are matched with each other, so that good preparation and stable twin crystal effects can be obtained, and the cumulative effects of grain boundary strengthening and precipitation strengthening of structure refinement can be simultaneously realized by combining with precipitation of low-temperature aging.

3. Compared with the traditional SPD technology for preparing high-density nano twin crystals by strong plastic deformation, the invention adopts the common rolling method which combines the materials relatively, can realize the effects of tissue ultra-fining and nano-fining, overcomes the limitation of the traditional SPD technology on the size of the produced product, and does not need to manufacture a grinding tool with complex requirements. The preparation process used by the invention only comprises the conventional industrial production procedures, such as rolling and heat treatment, and the technical process related by the invention is simple, easy to implement, low in production cost and beneficial to developing industrial application.

Drawings

FIG. 1 is a schematic view of a nano twin crystal reinforced toughening preparation method of high-toughness wear-resistant steel according to the present invention;

FIG. 2 is a typical structure transmission electron microscope photograph of high-density nanometer twin crystals of the high-toughness wear-resistant steel prepared by the invention.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

A high-strength and high-toughness wear-resistant steel and a preparation method of nano twin crystal enhanced toughening thereof comprise the following steps:

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.35% of C, 24.8% of Mn, 0.1% of Si, 1.0% of Al, 0.005% of S, 0.01% of P, 0.5% of Nb, 0.2% of Ti, 0.2% of V, 0.05% of N, rare earth RE: 0.02%, the balance being Fe and unavoidable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) homogenization heat treatment and cogging: carrying out high-temperature homogenization treatment on the cast ingot obtained in the step (1) at 1200 ℃, preserving heat for 4h, air-cooling to 1100 ℃ for forging, cooling to room temperature by water, casting to form a plastic film sealing sand box by negative pressure casting, and pumping out air in the mould by a vacuum pumping system, wherein the finish forging temperature is 950 ℃, the thickness of the material after cogging is 60 mm;

(3) hot rolling: and (3) heating the plate treated in the step (2) to 950 ℃, carrying out hot rolling after heat preservation for 2.0h, wherein the initial rolling temperature is 850 ℃, the final rolling temperature is 700 ℃, obtaining a plate with the final rolling thickness of 30mm, and carrying out air cooling to room temperature after rolling. The microstructure of the plate obtained by rolling is an ultrafine grained austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: and (4) reheating the material treated in the step (3) to 830 ℃, preserving the heat for 1.0h, then air-cooling to room temperature, and then cold-rolling at room temperature, wherein the deformation is 50%.

(5) Nano twin crystal stabilization and low-temperature aging treatment: and (4) heating the material treated in the step (4) to 400 ℃, carrying out dislocation recovery heat treatment for 2.0h, and then carrying out low-temperature aging treatment, wherein the aging temperature is 200 ℃, and the heat preservation time is 8 h.

The material obtained by the process has high-density nanometer twin crystals and nanometer precipitation, the average width is about 50nm, and the aging nanometer precipitation phase is about 15 nm. The high-strength and high-toughness wear-resistant steel reinforced by high-density nanometer deformation twin crystals and nanometer precipitated phases can be obtained, the yield strength of the prepared material exceeds 1000MPa, the tensile strength exceeds 1500MPa, and the fracture elongation is not lower than 20%.

Example 2

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: the alloy comprises the following chemical components in percentage by mass: 0.85% of C, 15.2% of Mn, 0.5% of Si, 0.5% of Al, 0.004% of S, 0.005% of P, 1.5% of Nb, 0.8% of Ti, 0.75% of V, 0.005% of N, rare earth RE: 0.5%, the balance being Fe and unavoidable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) homogenization heat treatment and cogging: carrying out high-temperature homogenization treatment on the cast ingot obtained in the step (1) at 1280 ℃, preserving heat for 2h, air-cooling to 1100 ℃ for forging, cooling to room temperature by water, casting to form a plastic film sealing sand box by negative pressure casting, and pumping out air in the mould by a vacuum pumping system, wherein the finish forging temperature is 980 ℃, the thickness of the material after cogging is 70 mm;

(3) hot rolling: and (3) heating the plate treated in the step (2) to 900 ℃, carrying out hot rolling after heat preservation for 5.0h, wherein the initial rolling temperature is 850 ℃, the final rolling temperature is 700 ℃, obtaining a plate with the final rolling thickness of 10mm, and carrying out air cooling to room temperature after rolling. The microstructure of the plate obtained by rolling is an ultrafine grained austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: and (4) reheating the material treated in the step (3) to 900 ℃, preserving heat for 0.5h, then air-cooling to room temperature, then cold-rolling at room temperature, and adopting a multi-pass small-deformation asynchronous rolling process, wherein the asynchronous rolling has a different speed ratio of 1.5, the two working rolls have the same diameter but different rotating speeds, and the deformation is 60%.

(5) Nano twin crystal stabilization and low-temperature aging treatment: and (4) heating the material treated in the step (4) to 450 ℃, carrying out dislocation recovery heat treatment for 1.0h, and then carrying out low-temperature aging treatment, wherein the aging temperature is 400 ℃, and the heat preservation time is 5 h.

The material obtained by the process has high-density nanometer twin crystals and nanometer precipitation, the average width is about 30nm, and the aging nanometer precipitation phase is about 10 nm. The high-density nano-deformation twin crystal and nano-precipitated phase reinforced high-strength and high-toughness wear-resistant steel can be obtained, the yield strength of the prepared material exceeds 1300MPa, the tensile strength exceeds 1700MPa, and the fracture elongation is not lower than 15%.

Example 3

A high-strength and high-toughness wear-resistant steel and a preparation method for enhancing toughening of nano twin crystal thereof are disclosed in figure 1, and the preparation method comprises the following steps:

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.5% of C, 20% of Mn, 0.25% of Si, 0.9% of Al, 0.005% of S, 0.01% of P, 1.0% of Nb, 0.5% of Ti, 0.5% of V, 0.01% of N, rare earth RE: 0.5%, the balance being Fe and unavoidable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) the homogenization heat treatment and the cogging are the same as the step (2) in the example 1, the homogenization temperature is 1250 ℃, the heat preservation is 3.0h, the cogging temperature is 1100 ℃, the medium rolling temperature is 950 ℃, and the cogging thickness is 60 mm.

(3) Hot rolling: heating the plate treated in the step (2) to 900 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the starting rolling temperature is 830 ℃, the final rolling temperature is 700 ℃, obtaining a plate with the final rolling thickness of 20mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the material treated in the step (3) is reheated to 830 ℃, kept warm for 0.5h, then air-cooled to room temperature, then cold-rolled, a multi-pass small-deformation asynchronous rolling process is adopted, the asynchronous rolling speed ratio is 2.0, the diameters of two working rolls are the same but the rotating speeds are different, the deformation is 50%, then recovery treatment is carried out, heating is carried out to 500 ℃, kept warm for 1h, then air-cooled to room temperature, and the primary deformation twin crystallization of the material structure and the dislocation structure recovery are realized, so that a first-level treated plate is obtained; rolling the first-stage treated plate at ultralow temperature, wherein the rolling temperature of an ultralow-temperature material is-80 ℃, the temperature is kept for 1 hour at the liquid nitrogen temperature, and the accumulated deformation is 30%;

(5) nano twin crystal stabilization and low-temperature aging treatment: and (3) heating the material treated in the step (4) to 400 ℃, carrying out dislocation recovery heat treatment for 6h, and then carrying out low-temperature aging treatment, wherein the aging temperature is 200 ℃, the heat preservation time is 6h, the average width of the treated high-density nano twin crystal is less than 40nm, and the aged nano precipitated phase is about 15 nm.

Example 4

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.8 percent of C, 24 percent of Mn, 0.5 percent of Si, 0.9 percent of Al, 0.003 percent of S, 0.006 percent of P, 0.6 percent of Nb, 0.3 percent of Ti, 0.3 percent of V, 0.02 percent of N, 0.02 percent of rare earth RE, and the balance of Fe and inevitable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) the homogenization heat treatment and the cogging were the same as in the step (2) of example 1;

(3) hot rolling: heating the plate treated in the step (2) to 950 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the initial rolling temperature is 850 ℃, the final rolling temperature is 720 ℃, obtaining a plate with the final rolling thickness of 15mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the material treated in the step (3) is heated to 900 ℃ again, heat preservation is carried out for 0.5h, then air cooling is carried out to room temperature, then cold rolling is carried out, a multi-pass small-deformation asynchronous rolling process is adopted, the differential speed ratio of asynchronous rolling is 1.1, the diameters and the rotating speeds of rollers are different, the deformation is 50%, then recovery treatment is carried out, heating is carried out to 500 ℃ and heat preservation is carried out for 1h, then air cooling is carried out to room temperature, so that primary deformation twin crystallization of the material tissue and dislocation tissue recovery are realized, and a first-level treated plate is obtained; rolling the first-stage treated plate at ultralow temperature, wherein the rolling temperature of an ultralow-temperature material is-80 ℃, the temperature is kept for 1 hour at the liquid nitrogen temperature, and the accumulated deformation is 30%;

(5) nano twin crystal stabilization and low-temperature aging treatment: and (3) heating the material treated in the step (4) to 400 ℃, carrying out dislocation recovery heat treatment for 6h, and then carrying out low-temperature aging treatment, wherein the aging temperature is 400 ℃, the heat preservation time is 4h, the average width of the treated high-density nano twin crystal is less than 50nm, and the aging nano precipitated phase is less than 15nm, so that the high-density nano deformation twin crystal and nano precipitated phase reinforced high-strength and high-toughness wear-resistant steel can be obtained.

Example 5

(1) the smelting alloy comprises the following components: 0.5 percent of C, 20.3 percent of Mn, 0.25 percent of Si, 0.9 percent of Al, 0.9 percent of Nb, 0.45 percent of Ti, 0.45 percent of V, 0.01 percent of N, 0.045 percent of rare earth RE, and the balance of Fe and inevitable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(3) hot rolling: heating the plate treated in the step (2) to 900 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the initial rolling temperature is 850 ℃, the final rolling temperature is 710 ℃, obtaining a plate with the final rolling thickness of 15mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the material treated in the step (3) is heated to 900 ℃ again, heat preservation is carried out for 0.5h, then air cooling is carried out to room temperature, then cold rolling is carried out, a multi-pass small-deformation asynchronous rolling process is adopted, the differential speed ratio of asynchronous rolling is 1.1, the diameters of rollers are different but the rotating speeds are the same, the deformation is 50%, then recovery treatment is carried out, heating is carried out to 500 ℃ and heat preservation is carried out for 1h, then air cooling is carried out to room temperature, so that primary deformation twin crystallization of material tissues and dislocation tissue recovery are realized, and a first-level treated plate is obtained; rolling the first-stage treated plate at ultralow temperature, wherein the rolling temperature of an ultralow-temperature material is-80 ℃, the temperature is kept for 1 hour at the liquid nitrogen temperature, and the accumulated deformation is 30%;

(5) nano twin crystal stabilization and low-temperature aging treatment: and (3) heating the material treated in the step (4) to 400 ℃ to perform dislocation recovery heat treatment for 6h, and then performing low-temperature aging treatment, wherein the aging temperature is 375 ℃, the heat preservation time is 4h, the average width of the treated high-density nano twin crystal is less than 50nm, the aged nano precipitated phase is less than 15nm, high-density nano deformed twin crystal and nano precipitated phase reinforced high-strength and high-toughness wear-resistant steel can be obtained, the yield strength of the prepared material exceeds 1030MPa, the tensile strength exceeds 1550MPa, and the fracture elongation is not lower than 19%.

Example 6

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.5 percent of C, 20 plus or minus 0.5 percent of Mn, 0.25 percent of Si, less than or equal to 1.0 percent of Al, 1.0 plus or minus 0.2 percent of Nb, 0.5 plus or minus 0.1 percent of Ti, 0.5 plus or minus 0.1 percent of V, 0.01 percent of N, rare earth RE: 0.05 plus or minus 0.01 percent, and the balance of Fe and inevitable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(2) the homogenization heat treatment and the cogging were the same as in the step (2) of example 2;

(3) hot rolling: heating the plate treated in the step (2) to 920 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the initial rolling temperature is 880 ℃, the final rolling temperature is 700 ℃, obtaining a plate with the final rolling thickness of 20mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the same as the step (4) in the example 3, wherein the rolling temperature of the secondary ultralow-temperature material is kept for 1 hour at the liquid temperature, and the accumulated deformation is 40%;

(5) nano twin crystal stabilization and low-temperature aging treatment: and (4) heating the material treated in the step (4) to 400 ℃ to perform dislocation recovery heat treatment for 6h, and then performing low-temperature aging treatment at 320 ℃ for 6h to obtain the high-density nano-deformation twin crystal and nano-precipitated phase strengthened high-strength and high-toughness wear-resistant steel.

Example 7

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.65% of C, 22% of Mn, 0.3% of Si, 1.0% of Al, 0.8% of Nb, 0.4% of Ti, 0.4% of V, 0.015% of N, rare earth RE: 0.25%, the balance being Fe and unavoidable impurities; uniformly stirring and smelting the components in a vacuum induction furnace, carrying out electroslag remelting, and then casting the components into a cast ingot under negative pressure;

(3) hot rolling: heating the plate treated in the step (2) to 930 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the initial rolling temperature is 980 ℃, the final rolling temperature is 800 ℃, obtaining a plate with the final rolling thickness of 10mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the material treated in the step (3) is heated to 900 ℃ again, is kept warm for 0.5h, is cooled to room temperature by air, is then cold-rolled, and adopts a multi-pass small-deformation asynchronous rolling process, wherein the differential speed ratio of asynchronous rolling is 1.7, the rolling temperature is-80 ℃, and the deformation is 75%;

(5) nano twin crystal stabilization and low-temperature aging treatment: and (3) heating the material treated in the step (4) to 400 ℃ to perform dislocation recovery heat treatment for 6h, and then performing low-temperature aging treatment, wherein the aging temperature is 320 ℃, the heat preservation time is 6h, the average width of the treated high-density nano twin crystal is less than 30nm, and the aged nano precipitated phase is less than 15nm, so that the high-density nano deformed twin crystal and the nano precipitated phase reinforced high-strength and high-toughness wear-resistant steel can be obtained.

Example 8

(1) alloy smelting and negative pressure casting: the alloy comprises the following chemical components in percentage by mass: 0.6% of C, 18% of Mn, 0.3% of Si, 0.5% of Al, 1.0% of Nb, 0.5% of Ti, 0.5% of V, 0.02% of N, rare earth RE: 0.25%, the balance being Fe and unavoidable impurities; smelting in an electric arc furnace, performing vacuum self-consumption and casting under negative pressure to form an ingot;

(3) hot rolling: heating the plate treated in the step (2) to 900 ℃, preserving heat for 2.0h, and then carrying out hot rolling, wherein the initial rolling temperature is 800 ℃, the final rolling temperature is 700 ℃, obtaining a plate with the final rolling thickness of 10mm, cooling the plate to room temperature after rolling, wherein the hot rolling mode is single-pass synchronous rolling, the roller temperature is room temperature, and the microstructure of the plate obtained by rolling is an ultrafine crystal austenite single-phase structure rich in defects and deformation twin crystals;

(4) nano twin biochemical treatment: the material treated in the step (3) is reheated to 830 ℃, kept warm for 0.5h, then air-cooled to room temperature, then cold-rolled, a multi-pass small-deformation asynchronous rolling process is adopted, the differential speed ratio of asynchronous rolling is 1.7, the diameters and the rotating speeds of rollers are different, the deformation is 50%, then recovery treatment is carried out, heating is carried out to 500 ℃, kept warm for 1h, then air-cooled to room temperature, and the primary deformation twin crystallization of the material tissue and the dislocation tissue recovery are realized, so that a first-level treated plate is obtained; rolling the first-stage treated plate at ultralow temperature, wherein the rolling temperature of an ultralow-temperature material is-80 ℃, the temperature is kept for 1 hour at the liquid nitrogen temperature, and the accumulated deformation is 30%;

(5) nano twin crystal stabilization and low-temperature aging treatment: heating the material treated in the step (4) to 400 ℃ for dislocation recovery heat treatment for 6h, and then performing low-temperature aging treatment, wherein the aging temperature is 220 ℃, the heat preservation time is 6h, the structure of the prepared high-strength and high-toughness wear-resistant steel material is single-phase ultrafine crystal austenite, high-stability and high-density nanometer twin crystal strengthening and nanometer precipitated phases are contained in the high-strength and high-toughness wear-resistant steel material, the width of the nanometer twin crystal is less than 20 nanometers, the precipitated phases are less than 10 nanometers, the yield strength is not lower than 1500MPa, the tensile strength exceeds 2000MPa, and the elongation is not lower than 8.0%.

Example 9

A high-strength and high-toughness wear-resistant steel and a preparation method for strengthening and toughening a nanometer twin crystal thereof,

the material preparation procedure was the same as in example 3;

the distinguishing technical characteristics are as follows: the first-stage twin room-temperature rolling deformation in the step (4) is 50%, and the reheating temperature is 500 ℃ to carry out dislocation recovery heat treatment for 1.0 h; the temperature of the secondary twinning treatment is-100 ℃, the differential speed ratio of asynchronous rolling is 1.5, and the rolling deformation is 40%; and (5) keeping the temperature of nano twin crystal stabilization treatment at 400 ℃ for 1h, then carrying out low-temperature aging treatment at 220 ℃ for 6h, wherein the prepared high-toughness wear-resistant steel material has a structure of single-phase ultrafine crystal austenite, contains high-stability and high-density nano twin crystal strengthening and nano precipitated phase inside, and has a nano twin crystal width of less than 20 nm, as shown in the example of figure 2. The precipitated phase is 5-10 nanometers, the yield strength is 1700MPa, and the tensile strength exceeds 2100 MPa.

Example 10

the material preparation procedure was the same as in example 8;

the distinguishing technical characteristics are as follows: the first-stage twin room-temperature rolling deformation in the step (4) is 50%, and the reheating temperature is 600 ℃ to carry out dislocation recovery heat treatment for 0.5 h; the temperature of the secondary twinning treatment is liquid nitrogen temperature, the differential speed ratio of asynchronous rolling is 1.2, and the rolling deformation is 50%; and (5) stabilizing and aging the nanometer twin crystal at 400 ℃, keeping the temperature for 6h, wherein the structure of the prepared high-toughness wear-resistant steel is single-phase superfine crystal austenite, the interior of the prepared high-toughness wear-resistant steel contains high-stability and high-density nanometer twin crystal strengthening and nanometer precipitated phases, the width of the nanometer twin crystal is 20 nanometers, the precipitated phases are 5-10 nanometers, the thickness of the plate is 4.0mm, the yield strength is 1600MPa, and the tensile strength exceeds 2000 MPa.

Claims

1. The high-strength and high-toughness wear-resistant steel is characterized by comprising the following components in percentage by weight: the alloy comprises the following chemical components in percentage by mass: 0.35-0.85% of C, 15.2-24.8% of Mn, 0.1-0.5% of Si, less than or equal to 1.0% of Al, less than or equal to 0.005% of S, less than or equal to 0.01% of P, 0.5-1.5% of Nb, 0.2-0.8% of Ti, 0.2-0.75% of V, 0.005-0.05% of N, rare earth RE: 0.02-0.5 percent, and the balance of Fe and inevitable impurities.

2. The high-strength-toughness wear-resistant steel as recited in claim 1, wherein: the alloy has a stacking fault energy of 24-30 kJ/m²The mass percentages of the added Nb, Ti and V satisfy: 2:1:1.

3. The high strength and toughness wear resistant steel of claim 1, wherein: the alloy comprises the following components in percentage by mass: 0.5-0.8% of C, 20-24% of Mn, 0.1-0.5% of Si, less than or equal to 1.0% of Al, less than or equal to 0.005% of S, less than or equal to 0.01% of P, 0.6-1.0% of Nb, 0.3-0.5% of Ti, 0.3-0.5% of V, 0.01-0.02% of N, and rare earth RE: 0.02-0.5%, and the balance of Fe and inevitable impurities.

4. The high strength and toughness wear resistant steel of claim 1, wherein: the steel comprises the following components in percentage by mass: 0.5 percent of C, 20 plus or minus 0.5 percent of Mn, 0.25 percent of Si, less than or equal to 1.0 percent of Al, 1.0 plus or minus 0.2 percent of Nb, 0.5 plus or minus 0.1 percent of Ti, 0.5 plus or minus 0.1 percent of V, 0.01 percent of N, rare earth RE: 0.05 +/-0.01%, and the balance of Fe and inevitable impurities.

5. The preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal reinforced toughening of the high-strength and high-toughness wear-resistant steel as claimed in claim 1, is characterized by comprising the following steps:

6. The method for preparing high-toughness wear-resistant steel and the nano twin crystal reinforced toughening of the high-toughness wear-resistant steel according to claim 5, wherein the smelting mode adopted in the step (1) is vacuum induction and is combined with any one or two of electric arc furnace smelting, slag remelting, vacuum smelting and vacuum consumable consumption, negative pressure casting is performed to form a plastic film sealing sand box, and a vacuum pumping system pumps out in-mold air; in the step (2), the homogenization temperature is 1250 ℃, the heat preservation is 2.0h, the initial rolling temperature is 1100 ℃, the final rolling temperature is 950 ℃, and the cogging thickness is 60 mm.

7. The preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening of the high-strength and high-toughness wear-resistant steel according to claim 5 are characterized in that the material in the hot rolling process in the step (3) is heated at 950 ℃, is subjected to hot rolling after being kept for 2.0-5.0 h, is subjected to initial rolling at 800-850 ℃ and final rolling at 700-750 ℃, and is obtained into a plate with the final rolling thickness of 10-20 mm, and is subjected to air cooling to room temperature after being rolled.

8. The high-toughness wear-resistant steel and the preparation method of the nano twin crystal enhanced toughening of the high-toughness wear-resistant steel as claimed in claim 5 are characterized in that: the nanometer twin biochemical treatment process in the step (4) comprises a first-stage cold rolling and a second-stage ultralow temperature rolling twin biochemical treatment process:

first-stage treatment: reheating the material treated in the step (3) to 800-900 ℃, preserving heat for 0.5-1.0 h, then air-cooling to room temperature, then cold-rolling until the deformation is not more than 50%, then carrying out recovery treatment, heating to 500-600 ℃, preserving heat for 0.5-1.0 h, and then air-cooling to room temperature to realize primary deformation twin crystallization of the material structure and recovery of the dislocation structure;

secondary nano twinning treatment: and (3) rolling the material subjected to the primary treatment at an ultralow temperature, wherein the rolling temperature of the ultralow-temperature material is lower than-60 ℃, and the accumulated deformation is 25-40%.

9. The high-toughness wear-resistant steel and the preparation method of the nano twin crystal enhanced toughening of the high-toughness wear-resistant steel as claimed in claim 5 are characterized in that: the nanometer twinning treatment in the step (4) comprises two-stage treatment, wherein the room-temperature rolling deformation of the first-stage twinning treatment is 40%, and the temperature of the recovery treatment is 500 ℃ and is kept for 1 h; the ultra-low temperature rolling of the second-stage twinning treatment is that the temperature is kept for 1.0 hour at the temperature of liquid nitrogen, and the accumulated deformation is 30 percent.

10. The high-toughness wear-resistant steel and the preparation method of the nano twin crystal enhanced toughening of the high-toughness wear-resistant steel as claimed in claim 5 are characterized in that: and (5) stabilizing the nanometer twin crystal, namely performing one-step treatment, heating to 400 ℃, keeping the temperature for 6 hours, wherein the treated tissue is a high-density nanometer twin crystal with the average width less than 50 nanometers, and the nanometer precipitated phase after aging treatment is not more than 15 nanometers.

11. The preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening thereof according to claim 5, wherein the twin treatment in the step (4) adopts a multi-pass small-deformation asynchronous rolling process, the differential ratio of asynchronous rolling is 1.1-2.0, and the asynchronous rolling comprises any one of the following modes: namely, the two working rolls have the same diameter but different rotating speeds, the rolls have different diameters but the same rotating speeds or the roll diameters and the rotating speeds are different, the microstructure of the obtained plate is an ultrafine crystal austenite single-phase structure, and the crystal is rich in high-density distorted annealing twin crystals and nano-scale deformation twin crystals with different orientations.

12. The preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening of the high-strength and high-toughness wear-resistant steel according to claim 8, wherein the secondary twin biochemical treatment temperature in the step (4) is-60 to-100 ℃, and the rolling total deformation is 30 to 40%.

13. The preparation method of the high-toughness wear-resistant steel and the nano twin crystal enhanced toughening thereof according to claim 5, wherein the rolling temperature in the step (4) is room temperature rolling, and the total rolling deformation is 50%.

14. The preparation method of the high-strength and high-toughness wear-resistant steel and the nano twin crystal enhanced toughening of the steel according to claim 5, wherein the rolling temperature in the step (4) is-80 ℃ and the deformation is 75%.

15. The high-toughness wear-resistant steel and the preparation method of the nano twin crystal enhanced toughening of the high-toughness wear-resistant steel as claimed in claim 5 are characterized in that: the prepared high-strength and high-toughness wear-resistant steel material has the structure of single-phase ultrafine grain austenite, contains high-stability and high-density nano twin crystal strengthening and nano precipitated phases in the steel material, has the nano twin crystal width of less than 20 nm, the precipitated phases of less than 10nm, the yield strength of not less than 1500MPa and the tensile strength of more than 2000 MPa.

16. The high-toughness wear-resistant steel and the preparation method of the nano twin crystal reinforced toughening of the high-toughness wear-resistant steel according to claim 5 are characterized in that the thickness of the high-stability high-density nano twin crystal reinforced high-toughness wear-resistant steel obtained after the low-temperature aging treatment in the step (5) is not less than 3 mm.