Preparation method of corrosion-resistant and impact-resistant high manganese steel wear-resistant lining plate

Abstract

The invention discloses a preparation method of a corrosion-resistant and impact-resistant high manganese steel wear-resistant lining plate, and relates to the technical field of wear-resistant materials, the preparation method comprises the following steps: S1, weighing raw materials according to the mass percentage; s2, raw material smelting; s3, rare earth purification is conducted, specifically, rare earth elements are added into the molten-state raw materials, and the molten-state raw materials are subjected to deoxidation and desulfurization treatment; s4, casting molding is conducted, the temperature from the bottom end of a casting to a riser is controlled to be decreased stage by stage, and directional solidification is achieved; s5, heat treatment is conducted, specifically, the casting is subjected to solution treatment and then subjected to water quenching to the room temperature; and S6, surface treatment is conducted, specifically, shot blasting treatment is adopted, surface oxide skin is removed, and a surface compressive stress layer is formed. The strength, hardness and high toughness of the high-manganese steel are guaranteed by controlling the content of carbon and manganese, meanwhile, single-phase austenite is obtained through solution treatment, the hardness is improved through carbon atom segregation through low-temperature aging, and the strength, hardness, toughness and corrosion resistance of the high-manganese steel lining plate are improved.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant materials technology, and in particular to a method for preparing a corrosion-resistant and impact-resistant high-manganese steel wear-resistant liner. Background Technology

[0002] High manganese steel, due to its work-hardening properties, can rapidly increase its surface hardness under impact loads, making it widely used in wear-resistant components such as crusher liners in mining and silo applications in metallurgical industries. However, traditional high manganese steel has two major drawbacks: firstly, it has poor corrosion resistance, easily undergoing electrochemical corrosion in environments containing moisture, salt, or acids and alkalis, leading to surface peeling and reduced wear resistance; secondly, it has low hardness at room temperature, making it difficult to form an effective hardened layer under low impact loads, resulting in a short service life.

[0003] Existing improvement technologies often enhance corrosion resistance by adding Cr and Ni elements, but excessive addition can lead to a significant decrease in impact toughness. For example, when the Cr content exceeds 4%, the impact toughness is lower than 120 J / cm². Another technology uses high-temperature quenching combined with high-temperature aging treatment, which can improve hardness, but it can also cause brittle phases to precipitate at grain boundaries, weakening impact resistance. Therefore, how to simultaneously improve hardness and corrosion resistance while ensuring the high impact toughness of high-manganese steel has become an urgent problem to be solved in the industry. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing corrosion-resistant and impact-resistant high-manganese steel wear-resistant liners, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a corrosion-resistant and impact-resistant high-manganese steel wear-resistant liner, comprising the following steps:

[0006] Step S1: Weigh the raw materials according to the mass percentage and make the raw material ratio of C, Mn, Cr, Ni, Mo, Si, P, S and Fe;

[0007] Step S2: Raw material smelting. First, scrap steel and pig iron are added to the smelting furnace to melt. After heating, Mn, Cr, Ni, Mo and Fe are added and heated to the molten state. After the holding stage, Si and Fe are added for deoxidation. After standing, the steel is tapped.

[0008] Step S3: Rare earth purification, which involves adding rare earth elements to the molten raw material to react with oxygen and sulfur elements, thereby deoxidizing and desulfurizing the molten raw material. At the same time, the rare earth elements react with the sulfur and oxygen in the raw material to generate spherical and near-spherical rare earth inclusions.

[0009] Step S4: Casting and molding, using water glass sand for molding, controlling the temperature from the bottom of the casting to the riser to decrease in stages, and allowing it to cool naturally before opening the mold;

[0010] Step S5: Heat treatment, the casting is heated to 1050-1100℃ and held for 4-6 hours for solution treatment, then water quenched to room temperature, and then the water-quenched casting is heated to 280-320℃ and held for 8-10 hours for low-temperature aging treatment, and then cooled to room temperature in the furnace.

[0011] Step S6: Surface treatment, using shot peening to remove surface oxide scale and form a surface compressive stress layer to offset some of the corrosion stress;

[0012] Step S7: Liner performance testing and effect verification, which involves testing the mechanical properties, corrosion resistance, and application performance of the liner.

[0013] Preferably, the proportions in step S1 are: C: 1.1%-1.3%, Mn: 11%-13%, Cr: 2.5%-3.5%, Ni: 1.0%-1.5%, Mo: 0.8%-1.2%, Si: 0.4%-0.6%, P≤0.07%, S≤0.05%, with the remainder being Fe. Step S2 involves controlling the content of added C and Mn, including the following steps:

[0014] Step S21: During the raw material smelting process, after heating to 1520-1550℃, add Mn, Cr, Ni, Mo and Fe, heat to the molten state, hold for 15-20 minutes, add Si and Fe at 1480-1500℃ for deoxidation, let stand for 5-8 minutes and then tap the steel. During the oxidation reaction stage, oxygen is blown into the molten steel. The target carbon and manganese content is controlled by controlling the oxygen blowing time, oxygen flow rate and the amount of cooling scrap steel added.

[0015] Step S22: In the reduction reaction stage, the carbon content is increased by inserting the carbon raiser deep into the molten steel and stirring it thoroughly to dissolve and absorb it, and the manganese content is increased by adding manganese alloy to the molten steel.

[0016] Preferably, the rare earth purification in step S3 includes the following steps:

[0017] Step S31: Rare earth elements react with residual dissolved oxygen and stable oxides and sulfides in molten steel to generate rare earth oxides, sulfides and oxysulfides with high melting point, low density and easy to float into the slag, thereby removing residual oxygen and sulfur elements in molten steel and achieving the purpose of deoxidation and desulfurization.

[0018] Step S32: Use rare earth elements to modify harmful and poorly shaped inclusions in steel into spherical and near-spherical rare earth inclusions, thereby controlling the morphology of the inclusions.

[0019] Step S33: Rare earth elements are dissolved in the steel matrix and enriched at the grain boundaries, which purifies the grain boundaries and inhibits the segregation of harmful phosphorus and sulfur elements, thus forming a microalloying effect.

[0020] Preferably, in step S4, the pouring temperature is controlled at 1420-1450℃, the pouring speed is 0.8-1.2 kg / s, and the casting is unpacked when it naturally cools to 800-850℃ after pouring. The cooling process during the casting stage includes the following steps:

[0021] Step S41: By setting chills at the end of the casting and at the thin-walled section, the local solidification sequence is changed, and the starting point of solidification is established, so that the casting starts to solidify from the end away from the riser and gradually moves towards the riser, with the riser being the last to solidify.

[0022] Step S42: By placing chills at thick parts and hot spots of the casting, the cooling is accelerated, so that it solidifies synchronously with or before the surrounding area, avoiding the formation of isolated liquid phase zones, and preventing the thin-walled parts from cooling and shrinking while the thick parts are still red-hot, which could lead to thermal cracking or deformation.

[0023] Step S43: By placing a chill at the far end of the riser action zone, the chill effect gradually weakens towards the riser, forming a smooth temperature gradient and avoiding sharp temperature steps between the strong chill zone and the non-chill zone.

[0024] Preferably, the solution treatment in step S5 involves heating the casting to 1050-1100℃ and holding it at that temperature for 4-6 hours, and includes the following steps:

[0025] Step S51: By heating the alloy above its solid solution temperature, the alloying elements are dissolved into the base metal to the maximum extent to form a uniform single-phase solid solution.

[0026] Step S52: By maintaining the solution temperature for a period of time, the dissolution process of the alloying elements is fully carried out, so that the composition of the workpiece cross section is uniform.

[0027] Step S53: Prevent solute atoms from precipitating from the supersaturated solid solution during the cooling process by rapidly cooling the workpiece to room temperature.

[0028] Preferably, the performance test in step S7 includes the following steps:

[0029] Step S71: Test the tensile properties, impact toughness, and hardness of the liner.

[0030] Step S72: Conduct a neutral salt spray test on the lining plate using sodium chloride solution to test the corrosion resistance of the lining plate;

[0031] Step S73: The performance and lifespan of the liner are verified for industrial application by performing an installation test on a wet ball mill.

[0032] Preferably, the test in step S71 includes:

[0033] Step S711: Apply a slowly increasing axial tensile force to the standard liner sample using a universal testing machine until it breaks, and determine the strength and plasticity of the liner under static tensile load to complete the tensile performance test of the liner.

[0034] Step S712: Using an impact testing machine, a pendulum is used to strike a standard liner with a notch in one go, and the impact energy absorbed is measured to reflect the liner's ability to resist fracture under high-speed impact load, thus completing the impact toughness test of the liner.

[0035] Step S713: The surface of the liner is pressed by the indenter of the hardness tester. The undeformed liner sample is measured as a reference value. The liner sample is then pre-deformed and its surface hardness is measured. The measured value is compared with the reference value to evaluate its work hardening ability and complete the hardness test of the liner.

[0036] Preferably, the corrosion resistance test in step S72 involves placing the lining sample in a sealed chamber, continuously spraying it with a 5% sodium chloride solution, maintaining a constant temperature inside the chamber, conducting a salt spray test, then using a scanning electron microscope to observe the morphology and corrosion type of the corrosion product film, and using an energy dispersive spectroscopy (EDS) instrument to analyze the elemental composition of the corrosion area and detect selectively dissolved elements and corrosion products.

[0037] Preferably, in step S5, the casting is quenched to room temperature and then heated to 280-320°C and held for 8-10 hours for low-temperature aging treatment. The low-temperature aging treatment involves heating the liner sample within a low-temperature range and holding it for a period of time, causing the precipitation of strengthening phases inside the sample. Solute atoms in the supersaturated solid solution agglomerate to form GP regions, which then become ordered to form transition phases. The transition phases transform into stable equilibrium phases, promoting the agglomeration of solute atoms and the formation of fine, dispersed transition phases.

[0038] Preferably, the surface treatment in step S6 involves impacting the liner surface with high-speed shot to remove residues, lightly cold-work hardening the surface to form a compressive stress layer, eliminating some casting stress, and strengthening the liner surface.

[0039] The technical effects and advantages of this invention are as follows:

[0040] This invention controls the carbon and manganese content, allowing carbon atoms to dissolve in the austenitic matrix, causing lattice distortion and improving the strength and hardness of the steel. Manganese is used to lower the martensitic transformation initiation temperature of the steel, enabling high-manganese steel to maintain a single, stable austenitic structure at room temperature or even low temperatures, ensuring high toughness. Furthermore, the raw materials are purified using rare earth elements to control the morphology of inclusions, with spherical compounds dispersed in the matrix, improving the isotropy of the high-manganese steel material and enhancing transverse impact toughness and fatigue life. Simultaneously, solution treatment fully dissolves excess carbides to obtain single-phase austenite, and low-temperature aging enhances hardness through carbon atom segregation, maintaining high toughness and improving the strength, hardness, and corrosion resistance of the high-manganese steel liner. Attached Figure Description

[0041] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0042] Figure 1 This is a schematic diagram of the process for preparing the high-manganese steel wear-resistant liner of the present invention;

[0043] Figure 2 This is a schematic diagram of the C and Mn content control process of the present invention;

[0044] Figure 3 This is a schematic diagram of the cooling process during the casting stage of the present invention;

[0045] Figure 4 This is a schematic diagram of the solution treatment process of the present invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention provides, for example Figures 1-4 The method for preparing a corrosion-resistant, impact-resistant, high-manganese steel wear-resistant liner, as shown, includes the following steps:

[0048] Step S1: Weigh the raw materials according to the following mass percentages: C: 1.1%-1.3%, Mn: 11%-13%, Cr: 2.5%-3.5%, Ni: 1.0%-1.5%, Mo: 0.8%-1.2%, Si: 0.4%-0.6%, P≤0.07%, S≤0.05%, with the remainder being Fe;

[0049] Step S2: Raw material smelting. First, scrap steel and pig iron are added to the smelting furnace to melt. After heating to 1520-1550℃, Mn, Cr, Ni, Mo and Fe are added. The mixture is heated to a molten state and held for 15-20 minutes. Si and Fe are added at 1480-1500℃ for deoxidation. After standing for 5-8 minutes, the steel is tapped.

[0050] Step S3: Rare earth purification, which involves adding rare earth elements to the molten raw material to react with oxygen and sulfur elements, thereby deoxidizing and desulfurizing the molten raw material and forming scum on the surface, which is then removed.

[0051] Step S4: Casting and molding, using water glass sand for molding, the casting temperature is controlled at 1420-1450℃, the casting speed is 0.8-1.2kg / s, the temperature is controlled to decrease in stages from the bottom of the casting to the riser to achieve directional solidification, and the casting is opened when it cools naturally to 800-850℃ after casting.

[0052] Step S5: Heat treatment, the casting is heated to 1050-1100℃ and held for 4-6 hours for solution treatment, then water quenched to room temperature, and then the water-quenched casting is heated to 280-320℃ and held for 8-10 hours for low-temperature aging treatment, and then cooled to room temperature in the furnace.

[0053] Step S6: Surface treatment, using shot peening to remove surface oxide scale and form a surface compressive stress layer to offset some of the corrosion stress;

[0054] Step S7: Liner performance testing and effect verification, which involves testing the mechanical properties, corrosion resistance, and application performance of the liner.

[0055] Step S2 involves controlling the content of C and Mn, including the following steps:

[0056] Step S21: During the raw material smelting process, oxygen is blown into the molten steel during the oxidation reaction stage. The target carbon and manganese content is controlled by controlling the oxygen blowing time, oxygen flow rate, and the amount of cooling scrap steel added.

[0057] Step S22: In the reduction reaction stage, the carbon content is increased by inserting the carbon raiser deep into the molten steel and stirring it thoroughly to dissolve and absorb it, and the manganese content is increased by adding manganese alloy to the molten steel.

[0058] By controlling the carbon content to 1.1%-1.3% and the manganese content to 11%-13%, a single-phase austenitic matrix is ​​ensured, providing a basis for work hardening. This also avoids carbide precipitation caused by excessively high carbon content. Carbon atoms dissolve in the austenitic matrix, causing lattice distortion and significantly improving the steel's strength and hardness. Manganese significantly lowers the martensitic transformation initiation temperature of the steel, allowing high-manganese steel to maintain a single, stable austenitic structure at room temperature or even low temperatures, ensuring its high toughness. Furthermore, manganese atoms can dissolve in the matrix, playing a certain role in solid solution strengthening. Maintaining a high manganese content stabilizes the austenite, ensuring a 100% austenitic structure in the as-cast state or after solution treatment. Adjusting the carbon content balances performance, improving strength, hardness, and wear resistance, as well as toughness and plasticity, while reducing carbides and resulting in a purer microstructure.

[0059] Adding small amounts of elements such as chromium, molybdenum, and nickel can strengthen the matrix through solid solution, refine the grains, and effectively reduce the ductile-brittle transition temperature. Among these, nickel is an effective element for improving low-temperature toughness.

[0060] Step S3, rare earth purification, includes:

[0061] Rare earth elements preferentially react with dissolved oxygen and dissolved sulfur in molten steel. and , Reaction generation , and Reaction generation , This process generates rare earth oxides, sulfides, and oxysulfides with high melting points and low density that easily float into the slag, removing residual oxygen and sulfur elements from the molten steel. , In addition to oxides, it can also generate more stable oxygen sulfides, achieving simultaneous deoxidation and desulfurization, and significantly reducing the O and S content in steel and non-ferrous metals;

[0062] Rare earth elements are used to modify harmful and poorly shaped inclusions in steel into spherical and near-spherical rare earth inclusions, thereby controlling the morphology of inclusions even if they have already formed in the steel. or Rare earth elements also displace oxygen and sulfur, resulting in spherical, thermally stable rare earth compounds through the aforementioned deoxidation, desulfurization, and displacement reactions. , , , These rare earth compounds, with their high melting point and high hardness, are solid at the temperature of molten steel and have a high solid-liquid interface energy in the molten steel. This causes them to precipitate in a spherical or near-spherical shape, without elongating with the deformation of the matrix. They are finely and diffusely distributed in the matrix, no longer forming continuous weak interfaces, which greatly improves the isotropy of steel and enhances transverse impact toughness and fatigue life.

[0063] Rare earth elements, dissolved in the steel matrix and enriched at grain boundaries, purify the grain boundaries and inhibit the segregation of harmful phosphorus and sulfur elements, thus forming a microalloying effect. Since the atomic radius of rare earth elements is much larger than that of iron atoms, after dissolving in the matrix, the dissolved rare earth atoms attract and fix impurity atoms that would otherwise tend to segregate at grain boundaries, forming stable compounds or dragging them within the grains—a phenomenon known as grain boundary pinning or cleaning effect. The large rare earth atoms dissolved in the matrix cause severe distortion of the iron lattice, resulting in a solid solution strengthening effect. The dissolved rare earth elements alter the phase transformation kinetics of steel. During heating, rare earth elements segregate at austenite grain boundaries, dragging the grain boundaries and thus refining the austenite. When the rare earth content in steel exceeds its solid solubility, it precipitates as dispersed, fine second-phase particles. The precipitates are nanoscale in size and are coherent or semi-coherent with the matrix. These fine particles pin grain boundaries and dislocations, further inhibiting grain growth and recrystallization, stabilizing the microstructure. Trace amounts of dissolved rare earth atoms strongly agglomerate at grain boundaries, hindering grain boundary migration through a dragging effect, preventing excessive grain growth during heat treatment, reducing grain boundary energy, and refining the as-cast structure. At the same time, it can purify grain boundaries, improve grain boundary bonding, thereby inhibiting high-temperature tempering brittleness and improving creep resistance.

[0064] When steel is slowly cooled after high-temperature tempering, impurities such as phosphorus and antimony tend to aggregate towards the grain boundaries, leading to a sharp decrease in toughness. Rare earth elements, by purifying and strengthening grain boundaries, enhance the bonding force between atoms, fundamentally suppressing high-temperature tempering brittleness. Creep deformation at high temperatures usually begins with grain boundary sliding and void nucleation. After rare earth purification and strengthening, the grain boundaries have a significantly enhanced ability to resist sliding and void nucleation, thereby significantly improving the creep resistance of steel.

[0065] Rare earth elements have a strong affinity for oxygen, sulfur, nitrogen, hydrogen, etc., and can form compounds with low density, high melting point, and stable properties. Their deoxidation and desulfurization capabilities are far stronger than those of traditional elements such as aluminum, silicon, and manganese. Rare earth elements can be used to remove harmful impurities in molten metal and improve the morphology and distribution of inclusions, thereby improving the purity and overall performance of metal materials.

[0066] Step S4, the cooling process for the casting stage, includes the following steps:

[0067] Step S41: By setting chills at the end of the casting and at the thin-walled section, the local solidification sequence is changed, and the starting point of solidification is established, so that the casting starts to solidify from the end away from the riser and gradually moves towards the riser, with the riser being the last to solidify.

[0068] Step S42: By placing chills in thick parts and hot spots of the casting, the cooling is accelerated, so that it solidifies synchronously with or before the surrounding area, thus avoiding the formation of isolated liquid phase zones;

[0069] Step S43: By placing a chill at the far end of the riser action zone, the chill effect gradually weakens towards the riser, forming a smooth temperature gradient and avoiding sharp temperature steps between the strong chill zone and the non-chill zone.

[0070] Staged cooling of castings involves controlling internal stress, microstructure transformation, and preventing defects during the solidification and cooling process. By controlling the cooling rate of different parts of the casting, the solidification sequence and temperature distribution are guided, thereby achieving proactive and managed staged cooling. Chills are blocks made of highly thermally conductive materials, usually cast iron, copper, or graphite, placed in specific locations within the mold cavity to quickly absorb and conduct heat from localized areas of the casting, accelerating the solidification and cooling rate of those areas.

[0071] Spatially, chills create pre-cooling and post-cooling zones, logically establishing a sequential cooling process. This achieves bottom-up, staged cooling, allowing the casting to solidify from the end furthest from the riser, gradually moving towards the riser until the riser is the last to solidify. First, chills are placed at the thin-walled or end of the casting, where the initial cooling rate is faster; the chills accelerate this process, creating the pre-cooling zone and completing the first stage of cooling. Then, chills are placed on the thicker sections of the casting to further accelerate cooling, causing the cooling curve to converge towards the thinner sections. This prevents the thinner sections from solidifying while the thicker sections are still red-hot. The cooling and shrinkage of the riser area leads to thermal cracking or deformation, greatly reducing the internal stress caused by asynchronous shrinkage. Then, starting from the far end of the riser's action zone, the contact area is gradually reduced, for example, by using grid-shaped chills or dot-shaped chills, so that the chilling effect is gradually weakened, avoiding the formation of sharp temperature steps between the strong chilling zone and the non-chilling zone. This reduces the thermal stress caused by sudden changes in cooling rate, lowers the risk of cracking, and ensures the unobstructed flow of the feeding channel, greatly improving the density of the casting, enhancing the stability and density of the high manganese steel liner, and ensuring the strength of the liner.

[0072] The solution treatment in step S5 includes the following steps:

[0073] Step S51: By heating the alloy above its solid solution temperature, the alloying elements are dissolved into the base metal to the maximum extent to form a uniform single-phase solid solution.

[0074] Step S52: By maintaining the solution temperature for a period of time, the dissolution process of the alloying elements is fully carried out, so that the composition of the workpiece cross section is uniform.

[0075] Step S53: Prevent solute atoms from precipitating from the supersaturated solid solution during the cooling process by rapidly cooling the workpiece to room temperature.

[0076] Solution treatment involves heating the alloy to an appropriate high temperature and holding it for a sufficient time to allow the soluble phase to fully dissolve into the base metal, forming a homogeneous single-phase solid solution. Typically, heating to a suitable temperature above the solution line is sufficient to allow the alloying elements or second phase to dissolve to the maximum extent in the matrix. Then, cooling is performed at a sufficiently rapid rate, usually using quenching. These elements remain in a supersaturated state in the matrix at room temperature. The solution treatment and quenching produce a supersaturated solid solution, creating conditions for subsequent aging treatment, thereby achieving extremely high strength and hardness. Simultaneously, the carbides are completely dissolved during solution treatment, allowing the Cr element to redistribute uniformly, resulting in a single austenitic structure, thus restoring its optimal corrosion resistance and achieving the goal of strengthening the strength, hardness, and corrosion resistance of high-manganese steel liners.

[0077] The performance test in step S7 includes the following steps:

[0078] Step S71: Test the tensile properties, impact toughness, and hardness of the liner.

[0079] Step S72: Conduct a neutral salt spray test on the lining plate using sodium chloride solution to test the corrosion resistance of the lining plate;

[0080] Step S73: The performance and lifespan of the liner are verified for industrial application by performing an installation test on a wet ball mill.

[0081] The tests in step S71 include tensile property testing, impact toughness testing, and hardness testing. The tensile property test follows GB / T 228.1-2021, applying a slowly increasing axial tensile force to a standard liner sample using a universal testing machine until fracture, determining the strength and plasticity of the liner under static tensile load. The impact toughness test follows GB / T 229-2020, using an impact testing machine to impact a notched standard liner with a pendulum in a single strike, measuring the absorbed impact energy to reflect the liner's ability to resist fracture under high-speed impact load. The hardness test follows GB / T 231.1-2018, using a hardness tester indenter to press the liner surface, measuring the hardness of an undeformed liner sample as a baseline. The liner sample is then pre-deformed, and its surface hardness is measured. The measured value after deformation is compared with the baseline value to determine the difference before and after hardening treatment, assessing its work hardening ability, and verifying the performance and effectiveness of the high-manganese steel liner.

[0082] The corrosion resistance test in step S72 involves placing the lining sample in a sealed chamber and conducting a neutral salt spray test according to GB / T 10125-2021, continuously spraying a 5% sodium chloride solution while maintaining a constant temperature inside the chamber. After 480 hours, the corrosion rate of the high-manganese steel lining is detected. Then, a scanning electron microscope is used to observe the morphology and corrosion type of the corrosion product film and to observe the degree of corrosion reaction of the lining, which facilitates the evaluation of corrosion resistance. The elemental composition of the corrosion area is analyzed by energy dispersive spectroscopy to detect selectively dissolved elements and corrosion products, determine the type of elements and corrosion products causing the corrosion of the lining, and facilitate the cleaning of corrosion products on the lining.

[0083] In the industrial application verification of step S73, before the high manganese steel liner is installed on the ball mill, the working surface of the liner is marked and the initial thickness and weight are accurately measured. The most representative chamber and position of wear is selected for the installation of the high manganese steel liner, such as the inlet end of the first chamber of the ball mill. The liner to be verified and the benchmark liner are installed and run in the same machine at the same time to determine the average service life and failure mode of the liner currently in use.

[0084] In the low-temperature aging process in step S5, after the high-manganese steel liner plate undergoes solution treatment and water quenching, the liner plate sample is heated and held at a low temperature for a period of time, causing the precipitation of strengthening phases inside. Solute atoms in the supersaturated solid solution agglomerate to form GP regions, and the GP regions become ordered to form transition phases. The transition phases transform into stable equilibrium phases, promoting the agglomeration of solute atoms and forming fine, dispersed transition phases. By controlling the casting process and heat treatment, fine and uniform austenite grains are obtained. Excess carbides can be dissolved by solution treatment at 1050-1100℃ to obtain single-phase austenite, and low-temperature aging at 280-320℃ does not produce brittle phases. Hardness is increased only through carbon agglomeration, while maintaining high toughness.

[0085] The shot peening surface treatment in step S6 involves impacting the surface of a metal part with a high-speed shot stream, causing plastic deformation and introducing residual compressive stress and work hardening into the surface layer. This significantly improves the fatigue strength and stress corrosion resistance of the part. The shot diameter is 0.8-1.2 mm, the pressure is 0.6-0.8 MPa, and the compressive stress value is 200-250 MPa. After removing the residue from the liner surface, the surface is lightly cold-worked to form a compressive stress layer. The surface compressive stress layer formed by shot peening can offset some of the corrosion stress, delay crack initiation, and further improve corrosion resistance and impact resistance, thus achieving the strengthening process of the liner surface.

[0086] The principle of this invention is as follows: By controlling the carbon and manganese content, carbon atoms dissolve in the austenitic matrix, causing lattice distortion and increasing the strength and hardness of the steel. Manganese is used to lower the martensitic transformation initiation temperature of the steel, allowing high-manganese steel to maintain a single, stable austenitic structure at room temperature or even low temperatures, ensuring the high toughness of high-manganese steel. Furthermore, the raw materials are purified by rare earth elements, controlling the morphology of inclusions. Rare earth compounds remain spherical at high temperatures, finely and diffusely distributed in the matrix, improving the isotropy of the steel and increasing the transverse impact toughness and fatigue life of the high-manganese steel liner. Simultaneously, excess carbides are dissolved through solution treatment to obtain single-phase austenite. Low-temperature aging increases hardness through carbon atom segregation, maintaining high toughness and improving the strength, hardness, and corrosion resistance of the high-manganese steel liner. Finally, by controlling the cooling rate of different parts of the casting, the solidification sequence and temperature distribution are guided, reducing thermal stress caused by sudden changes in cooling rate, lowering the risk of cracking, and improving the density of the liner casting.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method of making a corrosion and impact resistant high manganese steel wear plate, characterized in that, The method comprises the following steps: Step S1: weighing raw materials according to mass percentage, and preparing raw materials of C, Mn, Cr, Ni, Mo, Si, P, S and Fe; Step S2: raw material smelting, first adding scrap steel and pig iron into a smelting furnace for melting, adding Mn, Cr, Ni, Mo and Fe after heating, heating to a molten state, adding Si and Fe for deoxidation after the holding stage, and then tapping after standing; Step S3: rare earth purification, adding rare earth elements into the molten raw materials to react with oxygen and sulfur elements therein, and carrying out deoxidation and desulfurization treatment on the molten raw materials, and at the same time, the rare earth elements react with the sulfur and oxygen of the raw materials to generate spherical and near-spherical rare earth inclusions; Step S4: casting forming, adopting water glass sand molding, controlling the temperature of the bottom end of the casting to the riser to gradually decrease in stages, naturally cooling after pouring, and then unpacking; Step S5: heat treatment, carrying out solid solution treatment by heating and holding the casting, then water quenching to room temperature, and then heating and holding the water quenched casting to carry out low temperature aging treatment, and cooling to room temperature in the furnace; Step S6: surface treatment, adopting shot blasting treatment to remove surface oxide scale and form a surface compressive stress layer; Step S7: lining plate performance test and effect verification, detecting the mechanical properties, corrosion resistance and application performance of the lining plate, and observing the toughness, strength and corrosion resistance of the lining plate.

2. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate according to claim 1, wherein, The proportioning of step S1 is C: 1.1%-1.3%, Mn: 11%-13%, Cr: 2.5%-3.5%, Ni: 1.0%-1.5%, Mo: 0.8%-1.2%, Si: 0.4%-0.6%, P≤0.07%, S≤0.05%, and the remaining amount is Fe, and the C and Mn contents are controlled in step S2, which comprises the following steps: Step S21: in the raw material smelting process, adding Mn, Cr, Ni, Mo and Fe after heating to 1520-1550℃, heating to a molten state, holding for 15-20 min, adding Si and Fe for deoxidation at 1480-1500℃, and then tapping after standing for 5-8 min, and carrying out oxygen blowing in the oxidation reaction stage, and controlling the target carbon content and manganese content by controlling the oxygen blowing time, oxygen flow and the amount of cooling scrap steel added; Step S22: in the reduction reaction stage, increasing the carbon content by inserting a carbon additive into the deep part of the molten steel and fully stirring to dissolve and absorb it, and increasing the manganese content by adding a manganese alloy into the molten steel.

3. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate according to claim 2, wherein, The rare earth purification of step S3 comprises the following steps: Step S31: reacting the rare earth elements with the residual dissolved oxygen and stable oxides and sulfides in the molten steel to generate rare earth oxides, sulfides and oxysulfides with high melting points, small densities and easy floating into the slag, removing the residual oxygen and sulfur elements in the molten steel, and achieving the purposes of deoxidation and desulfurization; Step S32: modifying the harmful and poorly shaped inclusions in the steel into spherical and near-spherical rare earth inclusions by using rare earth, and achieving the purpose of controlling the inclusion shape; Step S33: The rare earth is solid-solved in the steel matrix, enriched in the grain boundary, and plays a role in purifying the grain boundary and inhibiting the segregation of phosphorus and sulfur harmful elements, forming a micro-alloying effect.

4. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate according to claim 3, wherein, The pouring temperature in the step S4 is controlled at 1420-1450℃, the pouring speed is 0.8-1.2 kg / s, and the casting is naturally cooled to 800-850℃ after pouring to open the box. The casting stage cooling includes the following steps: Step S41: By setting cold iron at the end of the casting and thin wall, the local solidification sequence is changed, the starting point of solidification is established, and the casting starts to solidify from the end away from the riser, gradually advancing towards the riser direction, and the riser is the last to solidify; Step S42: By setting cold iron at the thick part and hot spot of the casting, the cooling is accelerated, and it is solidified synchronously or in advance with the surrounding area, avoiding the formation of isolated liquid phase area, and avoiding the thick part being in a red-hot state while the thin wall part has already cooled and shrunk, leading to hot cracking or deformation; Step S43: By placing cold iron at the far end of the riser action area, and then towards the riser direction, the chilling effect of the cold iron gradually weakens, forming a smooth temperature gradient, avoiding the formation of sharp temperature steps between the strong chilling area and the non-chilling area.

5. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate according to claim 4, wherein, The solid solution treatment in the step S5 heats the casting to 1050-1100℃, and keeps for 4-6h, including the following steps: Step S51: By heating the alloy above the solid solution line temperature, the alloying elements are maximally dissolved into the matrix metal to form a uniform single-phase solid solution; Step S52: By keeping at the solid solution temperature for a period of time, the dissolution process of alloying elements is fully carried out, so that the cross-section composition of the workpiece is uniform; Step S53: By rapidly cooling the workpiece to room temperature, the precipitation of solute atoms from the supersaturated solid solution during the cooling process is prevented.

6. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate of claim 5, wherein, The performance test in the step S7 includes the following steps: Step S71: The tensile properties, impact toughness and hardness of the liner plate are tested; Step S72: The neutral salt spray test is carried out on the liner plate using sodium chloride solution to test the corrosion resistance of the liner plate; Step S73: The liner plate is tested on a wet ball mill to verify the service condition and life of the liner plate in industrial application.

7. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate according to claim 6, wherein, The test in the step S71 includes: Step S711: The universal material testing machine is used to apply a slowly increasing axial tensile force to the standard liner plate sample until it breaks, to measure the strength and plasticity indicators of the liner plate under static tensile load, and to complete the tensile property test of the liner plate; Step S712: The impact tester is used to impact the standard liner plate with a notch once with a pendulum to measure the impact energy absorbed, reflecting the ability of the liner plate to resist fracture under high-speed impact load, and completing the impact toughness test of the liner plate; Step S713: The indenter of the hardness tester is pressed against the surface of the liner plate, and the un-deformed liner plate sample is measured as a reference value. Then the surface hardness of the liner plate sample is measured after pre-deformation, and the measured value is compared with the reference value to evaluate the work hardening ability, and the hardness test of the liner plate is completed.

8. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate of claim 7, wherein, The corrosion resistance test in the step S72 is performed by placing the lining sample in a closed box, continuously spraying 5% sodium chloride solution, keeping the temperature in the box constant, and performing salt spray test. Then, the morphology and corrosion type of the corrosion product film are observed by using a scanning electron microscope, and the element composition of the corrosion area is analyzed by using an energy spectrometer to detect the selectively dissolved elements and the corrosion products.

9. The method of manufacturing a corrosion and impact resistant high manganese steel wear plate of claim 8, wherein, In the step S5, the water quenching is cooled to room temperature, and then the water quenched casting is heated to 280-320℃ and kept for 8-10h to perform low temperature aging treatment. The low temperature aging treatment is a process of heating and keeping the lining sample in a low temperature range for a period of time to make the internal strengthening phase precipitate. The solute atoms in the supersaturated solid solution are segregated to form GP zones. The GP zones are ordered to form transition phases. The transition phases are transformed into stable equilibrium phases to promote the segregation of solute atoms and the formation of fine and dispersed transition phases.

10. The method of making a corrosion and impact resistant high manganese steel wear plate of claim 9, wherein, In the step S6, the surface treatment is performed by impacting the lining surface with high-speed sprayed steel shots to remove the residues on the lining surface, slightly cold hardening the surface to form a compressive stress layer, eliminating part of the casting stress, and performing the strengthening processing of the lining surface.

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