Melt impact molding method for controlling carbides in alloy ingots

Abstract

This application provides a method for refining carbides of high-carbon high-alloy steel and relates to the field of manufacturing methods for alloy steel. The method for refining carbides of high-carbon high-alloy steel includes the steps of preparing raw materials according to the chemical element composition of high-carbon high-alloy steel, smelting to obtain high-carbon high-alloy molten steel, superheating the high-carbon high-alloy molten steel to Tm+(50~100)°C to obtain high-carbon high-alloy molten metal, depositing the high-carbon high-alloy molten metal into a preset water-cooled copper mold at a rate of 30~160 g / s through an inert gas, and solidifying and forming to obtain a high-carbon high-alloy ingot, and performing a heat treatment process on the high-carbon high-alloy ingot. According to the method for refining carbides of high-carbon high-alloy steel of this application, high-carbon high-alloy steel with a dense structure and fine carbides can be obtained.

Description

Technical Field

[0001] This application claims the priority of the Chinese patent application with the application number CN 202210485310.1 and the title " Method for refining carbides in high-carbon high-alloy steel ", filed with the China National Intellectual Property Administration on May 6, 2022, and all its contents are incorporated herein by reference. The present invention relates to the field of methods for manufacturing alloy steel, and specifically to a method for refining carbides in high-carbon high-alloy steel. The present invention relates to the field of methods for manufacturing alloy steel, and specifically to a melt impact forming method for controlling carbide of alloy ingots.

Background Art

[0002] Currently, due to the high carbon content and high alloy element content, high-carbon high-alloy steel is prone to generating coarse eutectic carbides, severe segregation, non-uniform structure, and the mechanical properties and wear resistance of high-carbon high-alloy steel are greatly restricted. The manufacturing methods of high-carbon high-alloy steel mainly include traditional casting methods, electroslag remelting methods, injection molding methods, powder metallurgy methods, etc. Among the above manufacturing methods, traditional casting methods and electroslag remelting methods are widely used in mass industrial production, but they cannot effectively solve the problem of coarse carbides in the structure and have severe segregation. Injection molding is a rapid solidification technology that uses refined liquid metal, sprays it into droplet jets, deposits semi-solidified droplet particles on a substrate, and rapidly solidifies them to form a casting. The injection molding method can refine the structure of metal materials, homogenize the composition, and eliminate macrosegregation. However, in this method, the degree of structure refinement is low, excessive scattering of spray droplets is likely to occur, the yield is low, and the formed metal material has inherent pores due to its loose structure.

Summary of the Invention

Problems to be Solved by the Invention

[0003] An object of the present invention is to provide a melt impact forming method for controlling carbide of alloy ingots that can obtain high-carbon high-alloy steel with a dense structure and fine carbides. [Means for solving the problem]

[0004] This invention relates to alloy ingots carbide We provide a melt impact molding method that controls the process. The steps include: preparing raw materials according to the chemical elemental composition of high-carbon high-alloy steel, and smelting them to obtain high-carbon high-alloy molten steel; The steps include: overheating high-carbon high-alloy molten steel to Tm+(50~100)℃ to obtain high-carbon high-alloy molten metal; depositing the high-carbon high-alloy molten metal at a rate of 30~160 g / s into a pre-set water-cooled copper mold via an inert gas, and solidifying and shaping it to obtain a high-carbon high-alloy ingot; The process includes the step of subjecting a high-carbon high-alloy ingot to a heat treatment process.

[0005] In the above technical solution, the molten alloy steel is superheated, and after the molten alloy reaches a predetermined temperature, it is deposited at a constant rate into a water-cooled copper mold under the propulsion of an inert gas, where it is shaped and solidified to form a high-carbon high-alloy ingot with fine carbides. Subsequent heat treatment further alters the microstructure and distribution of the high-carbon high-alloy steel, improving its service life.

[0006] Of these, the degree of overheating must not be too high, as too high a degree of overheating leads to coarsening of the solidified tissue. The degree of overheating must not be too low, as too low a degree of overheating results in poor fluidity, making it difficult to obtain a quick impact and causing the nozzle to clog easily.

[0007] In this method, molten metal is shaped by impact at a constant speed, causing the crystal grains and primary carbides to be crushed by the impact. This refines the crystal grains and carbides, significantly reducing the occurrence of pores. Furthermore, the utilization rate of the molten metal is high, and there is no waste of molten metal. The biggest difference between the melt impact method and conventional injection molding is that the microstructure of the formed ingot is dense and uniform, with fine carbides. During the subsequent heat treatment process, the crystal grains recrystallize based on dislocations and crushed primary carbides, resulting in fine crystal grains, fine carbides, and a uniform distribution. As a result, the strength, toughness, and wear resistance of the high-carbon high-alloy steel are improved, and the service life is extended.

[0008] Optionally, the elemental composition of high-carbon high-alloy steel is, in weight percent, C: 1.5-2.5%, W: 2.5-10%, Mo: 3-7%, Cr: 4-6%, V: 2-10%, Si: 0.3-0.6%, Mn: 0.3-0.8%, with the remainder being Fe.

[0009] In the above technical solution, the carbon content is controlled to 1.5-2.5%, with some of it penetrating the matrix to induce solid solution strengthening and ensure the matrix's strength and hardness, while other parts combine with alloying elements to form various types of alloy carbides. If the carbon content is insufficient, secondary hardening ability is lacking, reducing the strength and hardness of the matrix. At the same time, the number of primary carbides also decreases relatively, reducing the steel's wear resistance and service life. Conversely, if the carbon content is too high, a large amount of alloy carbides are formed, and the non-uniformity of the carbides increases significantly, ultimately leading to a significant decrease in the steel's plasticity, toughness, and forgeability.

[0010] The tungsten content is controlled to 2.5-10%, forming a certain amount of insoluble primary carbides, which improves the wear resistance of the steel. It also inhibits grain growth during quenching, thereby refining the grains. If the tungsten content is too high, the density increases, and during solidification, coarse, fishbone-like M6C eutectic carbides tend to precipitate, which negatively affects plasticity.

[0011] The molybdenum content is controlled to 3-7%, and not only does it solid-solve in the matrix to achieve solid-solution strengthening, but it can also form M2C and M6C carbides with carbon, playing a role similar to that of tungsten in high-carbon high-alloy steels.

[0012] The chromium content is controlled to 4-6%. Cr is one of the most beneficial elements for improving hardenability. When combined with elements such as W, Mo, and V, it can reduce mismatch between the secondary carbide precipitate phase and the matrix, lower the nucleation activation energy, promote the concentrated dispersion and precipitation of large amounts of secondary carbides, and greatly contribute to secondary hardening. If the chromium content is too low, it has a significant impact on the hardenability of high-carbon high-alloy steel. Hardenability is especially important for high-carbon high-alloy steel, and only an appropriate chromium content can ensure sufficient hardenability of high-carbon high-alloy steel. If the chromium content is too high, temper brittleness of the high-alloy steel easily occurs, negatively affecting its plasticity.

[0013] The vanadium content is controlled to 2-10%, with some dissolving in the matrix and others forming primary MC carbides with carbon. The vanadium dissolved in the matrix can significantly enhance the secondary hardening effect of the steel, while the undissolved VC carbides prevent particle growth during quenching and heating, significantly improving the wear resistance of the steel. Too little vanadium content negatively affects the hardness and wear resistance of high-carbon high-alloy steel, while too much vanadium content forms a large amount of MC carbides, which have very high hardness and brittleness and do not contribute to the plasticity or toughness of the steel.

[0014] The manganese content is controlled to 0.3-0.8%. At low concentrations, manganese exhibits good deoxidation and desulfurization effects, contributing to the strength and wear resistance of high-alloy steel and improving hardenability. Manganese can eliminate or weaken the thermal brittleness of steel caused by sulfur, thus improving the hot workability of high-alloy steel. As the manganese content increases, the retained austenite content increases, reducing the thermal stability and hardness of high-carbon high-alloy steel.

[0015] The silicon content is controlled to 0.3-0.6%. Silicon strengthens the matrix, improving the strength, hardness, and hardenability of high-alloy steel, suppressing the formation of M3C, refining M3C, and promoting the conversion of M2C to MC and M7C3, etc. If the silicon content is too high, the formation of primary coarse MC is easily promoted, increasing the decarbonization tendency of high-alloy steel and reducing the tempering stability of high-alloy steel.

[0016] Optionally, the heat treatment process includes sequential high-temperature solid solution, low-temperature interrupted quenching, and tempering treatments, with the high-temperature solid solution being held at 900-1050°C for 15-60 minutes, the low-temperature interrupted quenching at 700-860°C for 1-2 hours, and the tempering treatment at 520-580°C for 3-4 hours.

[0017] In the above technical solution, the ingot heat treatment process is a further operation and continuation of the carbide refinement, maintaining the microstructure of the fine carbides in the ingot until the final state after heat treatment. First, the high-carbon high-alloy ingot is subjected to high-temperature solid solution treatment to sufficiently dissolve the fine carbides in the matrix, removing and dissolving individual coarse residual carbides. Because the carbides in the ingot are fine, using high-temperature solid solution shortens the temperature holding time and saves energy. The purpose of interrupted quenching is to refine the matrix particles and spheroidize the carbides. Since the carbides are sufficiently dissolved after high-temperature solid solution, the subsequent interrupted quenching temperature can be lowered, eliminating the need for a high austenitizing temperature, and the lower interrupted quenching temperature avoids carbide accumulation and growth. The tempering treatment aims to release residual stresses while adjusting the hardness and toughness of the high-carbon high-alloy steel.

[0018] Optionally, after high-temperature solid solution is completed, oil quenching is performed to room temperature, followed by low-temperature interrupted quenching, and / or, after low-temperature interrupted quenching is completed, water quenching is performed to the martensitic transformation point, oil quenching is performed to room temperature, and then tempering is performed.

[0019] In the above technical solution, after the high-temperature solid solution reaches the preset holding time, it is taken out of the kiln and oil quenched to room temperature. After the low-temperature interrupted quenching is completed, it is rapidly water quenched to the M point (martensite transformation point) to maintain the fine size of the carbides, avoid the complete growth of the carbides by slow cooling, and at the same time, the distribution of dislocations is improved by rapid cooling, the strength of the matrix is enhanced, and the oil quenching after the M point is to avoid quenching deformation, cracking, etc. after reaching room temperature.

[0020] Optionally, the heat treatment method includes evacuating the chamber containing the high-carbon high-alloy molten steel to 100-400 Pa, filling it with an inert gas for protection, and then heating the high-carbon high-alloy molten steel to obtain a high-carbon high-alloy molten bath.

[0021] Optionally, the heat treatment is carried out by the method of coil heating.

[0022] Optionally, the molten bath deposition method includes filling an inert gas for protection, heating the high-carbon high-alloy molten steel to obtain a high-carbon high-alloy molten bath, and then continuously filling an inert gas to promote the injection of the high-carbon high-alloy molten bath into the external chamber.

[0023] In the above technical solution, after evacuating the chamber, it is filled with an inert atmosphere for protection. When the molten bath reaches the superheat temperature, an inert gas flow is filled into the molten bath, so a certain pressure difference is generated between the molten bath and the external chamber, and the molten bath is rapidly injected. Since the injection is mainly controlled by the air flow, the realization and operation are simple.

[0024] Optionally, the high-carbon high-alloy molten bath is deposited under the action of a pressure difference, and the pressure difference is 0.05-0.25 MPa.

[0025] In the above technical solution, if the pressure difference is too large, molten bath scattering is likely to occur. If it is less than this pressure difference range, an effective impact force cannot be formed, and the coarse eutectic structure cannot be effectively refined.

[0026] Optionally, the distance between the nozzle outlet of the chamber where the high-carbon high-alloy molten metal is located and the water-cooled copper mold is 11 to 20 cm, and / or the water outlet temperature of the water-cooled copper mold is 30 to 45 °C.

[0027] In the above technical solution, if the injection distance is too small, the alloy molten steel is likely to scatter, and if the injection distance is too large, an effective impact force cannot be maintained.

[0028] Optionally, the outlet shape of the nozzle is a round hole type or a slit type, and all the nozzles are arranged in an array.

Brief Description of the Drawings

[0029] To more clearly explain the technical solution of the embodiments of this application, the following briefly describes the attached drawings used in the embodiments of this application. The following drawings show only specific embodiments of this application, and therefore are not considered to limit the scope. It should be understood that for those skilled in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0030] [Figure 1] It is a microscopic structure diagram of the ingot obtained in Example 1. [Figure 2] It is a microscopic structure diagram of the ingot obtained in Example 2. [Figure 3] It is a microscopic structure diagram of the ingot obtained in Comparative Example 1. [Figure 4] It is a microscopic structure diagram of the high-carbon high-alloy steel obtained in Example 1.

Modes for Carrying Out the Invention

[0031] The applicant discovered that high-carbon, high-alloy steels, due to their high carbon content and alloying elements, are prone to forming coarse eutectic carbides, leading to severe segregation. The microstructure of current high-carbon, high-alloy steel castings (castings obtained by forming) is highly heterogeneous, consisting mainly of martensite, retained austenite, and various carbides. Various carbides (the most common MC, M2C, M6C, etc.) are unevenly distributed and have different shapes. In particular, coarse reticular eutectic carbides are distributed at grain boundaries, splitting the matrix and reducing serviceability. In the case of high-carbon, high-alloy steel castings, refining the carbides and distributing them uniformly is especially important for subsequent thermomechanical deformation and improvement of mechanical properties. Coarse reticular eutectic carbides in castings are destroyed by subsequent processes such as forging and rolling, significantly affecting mechanical properties. Even with forging and rolling processes, it is difficult to uniformly refine and disperse the carbides, and costs are high.

[0032] Furthermore, most high-carbon high-alloy steel products are primarily castings, meaning they undergo no subsequent thermomechanical deformation, only heat treatment. This heat treatment cannot alter the distribution or morphology of coarse carbides. For example, ingots manufactured using existing injection molding techniques have inherent pores, and in the case of cast alloy steel, since there is no subsequent forging process, pores still exist in the ingot after heat treatment, significantly reducing its lifespan. Therefore, refining coarse eutectic carbides so that high-carbon high-alloy steel castings have a microstructure of fine carbides from the beginning is crucial for improving their mechanical properties.

[0033] This application utilizes the rapid impact of liquid flow, the liquid-solid interface of a self-agitating molten pool, and high-speed impact forces to break down dendritic crystals, increase nucleation points, and create conditions for grain refinement. When combined with specific heat treatment processes, this method is highly effective in refining the primary carbides of high-carbon, high-alloy steel ingots.

[0034] To further clarify the purpose, technical solutions, and advantages of the embodiments of this application, the technical solutions in the embodiments of this application are described below clearly and completely. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or equipment used without manufacturer's instructions are common products available commercially.

[0035] The following describes the alloy ingot according to the embodiment of this application. carbide This document provides a detailed explanation of the melt impact molding method that controls this process.

[0036] The embodiments of this application are of an alloy ingot carbide The present invention provides a melt impact molding method that controls the process of producing high-carbon high-alloy ingots by the melt impact method and a heat treatment process, and includes the following steps. (1) Production of high-carbon high-alloy ingots by melt impact method S1, depending on the chemical elemental composition of the high-carbon high-alloy steel, the raw materials are prepared to contain, by weight percent, C: 1.5-2.5%, W: 2.5-10%, Mo: 3-7%, Cr: 4-6%, V: 2-10%, Si: 0.3-0.6%, Mn: 0.3-0.8%, with the remainder being Fe, and then smelted to obtain high-carbon high-alloy molten steel. S2. The chamber containing the high-carbon high-alloy molten steel is evacuated to 100-400 Pa, and an inert gas is filled for protection, creating an inert atmosphere protection for the entire chamber. Next, the high-carbon high-alloy molten steel is heated using the coil heating method and superheated to a temperature range 50-100°C above the melting point, i.e., Tm+(50-100)°C, to obtain high-carbon high-alloy molten metal. The chamber containing the high-carbon high-alloy molten steel is then continuously filled with inert gas so that a pressure difference of 0.05-0.25 MPa is formed between the chamber containing the high-carbon high-alloy molten steel and the outer chamber. As a result, the high-carbon high-alloy molten metal is injected into the outer chamber at a speed of 30-160 g / s under this pressure difference and deposited in a pre-set water-cooled copper mold. The distance between the nozzle outlet of the chamber where the high-carbon high-alloy molten metal is located and the water-cooled copper mold is 11-20 cm, and the water outlet temperature of the water-cooled copper mold is 30-45°C. Solidification and molding are then performed to obtain a high-carbon high-alloy ingot.

[0037] In the embodiments of this application, raw materials are placed in a crucible, melted using a medium-frequency induction furnace to obtain high-carbon high-alloy molten steel. The chamber of the medium-frequency induction furnace is sealed, and the coil is heated to produce molten steel, which is then further heated to produce molten metal. A graphite nozzle is located at the bottom of the crucible, and the nozzle outlet shape is either a round hole type or a slit type. All nozzles are arranged in an array, and the molten metal passes through the nozzles due to the pressure difference, deposits at a constant rate in a water-cooled copper mold, is formed and solidified to obtain a high-carbon alloy ingot having fine carbides.

[0038] (2) Heat treatment process S3 involves applying a high-temperature solid solution to a high-carbon, high-alloy ingot, holding it at 900-1050°C for 15-60 minutes, and then oil quenching it to room temperature. The ingots that have gone through steps S4 and S3 are subjected to low-temperature interrupted quenching, held at 700-860°C for 1-2 hours, water-quenched to the martensitic transformation point (M point), and then oil-quenched to room temperature. The ingot that has gone through steps S5 and S4 is tempered and held at 520-580°C for 3-4 hours to obtain high-carbon high-alloy steel.

[0039] Examples The features and performance of this application will be described in more detail below with reference to the examples.

[0040] Example 1 This embodiment provides a high-carbon high-alloy steel, the manufacturing process of which is as follows: S1, a high-carbon high-alloy steel, was prepared by placing the raw materials in a smelting vessel according to its chemical elemental composition: C: 2.5%, W: 4.1%, Mo: 2.9%, Cr: 5.0%, V: 8.2%, Si: 0.5%, Mn: 0.3%, with the remainder being Fe. A medium-frequency induction furnace was used to smelt the materials at a melting point of 1398°C to obtain high-carbon high-alloy molten steel. S2, the chamber of the medium-frequency induction furnace was evacuated to 200 Pa, then filled with inert gas to create an inert atmosphere protection state throughout the chamber. Next, the high-carbon high-alloy molten steel was heated to 1450°C, i.e., Tm+52°C, to obtain a high-carbon high-alloy molten metal. The inert gas was continuously filled so that a pressure difference of 0.15 MPa was formed between the chamber and the outer chamber. As a result, the high-carbon high-alloy molten metal in the crucible was injected at a rate of 100 g / s from a nozzle at the bottom of the crucible into the outer chamber under the pressure difference, and deposited in a pre-set water-cooled copper mold. The distance between the nozzle outlet and the water-cooled copper mold was 15 cm, and the water outlet temperature of the water-cooled copper mold was 40°C. Solidification and molding were performed to obtain a high-carbon high-alloy ingot. S3, a high-carbon high-alloy ingot, was subjected to a high-temperature solid solution treatment, held at 1000°C for 30 minutes, and then oil-quenched to room temperature. The ingots that had gone through steps S4 and S3 were subjected to low-temperature interrupted quenching, held at 800°C for 1.5 hours, water-quenched to the martensitic transformation point (M point), and then oil-quenched to room temperature. The ingots that had gone through steps S5 and S4 were tempered and held at 550°C for 3.5 hours to obtain high-carbon high-alloy steel.

[0041] Example 2 This embodiment provides a high-carbon, high-alloy steel, and the manufacturing process differs from that of Example 1 in that the pressure difference was controlled to 0.25 MPa.

[0042] Example 3 This embodiment provides a high-carbon high-alloy steel, and the manufacturing process differs from that of Example 1 in that the injection speed is 50 g / s.

[0043] Comparative Example 1 This comparative example provides a high-carbon high-alloy steel, and the manufacturing process differs from that of Example 1 in that the high-carbon high-alloy molten steel is heated to 1450°C, cast according to a conventional die casting method to obtain an ingot, and then cooled to room temperature.

[0044] Comparative Example 2 This comparative example provides high-carbon high-alloy steel, and the manufacturing process differs from that of Example 1 in that the high-carbon high-alloy molten steel is heated to 1450°C, cast according to a conventional die casting method to obtain an ingot, and then subjected to a heat treatment process similar to that of Example 1.

[0045] Comparative Example 3 This comparative example provides high-carbon high-alloy steel, and the manufacturing process differs from that of Example 1 in that the high-carbon high-alloy ingot was heated to 800°C and held for 4 hours, after which it was naturally cooled in a furnace.

[0046] Comparative Example 4 This comparative example provides a high-carbon high-alloy steel. The manufacturing process differs from Example 1 in that no heat treatment is performed, and the molten steel obtained by smelting is injected. However, because the viscosity of the molten alloy is high, it cannot be injected smoothly from the nozzle, and the nozzle tends to clog.

[0047] Figure 1 shows the microstructure of the ingot from Example 1, Figure 2 shows the microstructure of the ingot from Example 2, and Figure 3 shows the microstructure of the ingot from Comparative Example 1. Note: Figures 1-3 all show the original microstructure before heat treatment.

[0048] Analysis revealed that the microscopic tissue contained two types of carbides: the gray carbides were MC-type carbides, and the white carbides were M2C carbides. The ingots in Figures 1 and 2 were formed according to a specific melt impact method. As a result, the gray carbides were uniformly dispersed particles, very fine and homogeneous, while the white carbides were band-shaped or rod-shaped. The carbides in the ingot of Figure 2 were finer than those in the ingot of Figure 1 due to a stronger impact effect. The gray carbides in the ingot of Figure 3 varied in shape from petal-shaped to thick mesh-like structures, severely aggregated and dividing the matrix, while the white carbides were band-shaped or rod-shaped and larger in size than those in Figures 1 and 2.

[0049] Furthermore, as shown in the following table, we performed a statistical analysis of two carbide sizes from different ingot microscopy tissues using Image-Pro Plus. JPEG0007842486000001.jpg35163

[0050] Figure 4 shows the microstructure (optical microscope image) of the high-carbon high-alloy steel (ingot that has undergone a specific heat treatment) of Example 1. As can be seen from Figure 4, the microstructure of the final state is mainly composed of MC carbides and M6C carbides.

[0051] Comparing Figure 1 and Figure 4, the reasons for the changes in the microstructure are as follows: The MC-type carbides in the ingot are stable and do not change during subsequent heat treatment, while the M2C carbides are a metastable phase and decompose into MC and M6C during subsequent heat treatment. After heat treatment of the ingot, the size of the M2C carbides cannot be counted and the ingot is mainly composed of MC-type carbides and M6C carbides.

[0052] The microstructure of the high-carbon high-alloy steel of Comparative Example 3 (the ingot was not particularly heat-treated) consists of pearlite and granular carbides. Compared to the alloy steel of Example 1, this alloy steel is considered to be in an intermediate state (spheroidizing annealing) that reduces the alloy hardness and prepares the structure for subsequent quenching and tempering.

[0053] In summary, the alloy ingot according to the embodiment of this application carbide According to the melt impact molding method that controls this process, it is possible to obtain high-carbon, high-alloy steel with a dense structure and fine carbides.

[0054] The foregoing are merely embodiments of this application and are not intended to limit the scope of this application. Those skilled in the art will be able to conceive of various modifications and variations of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application shall be included within the scope of protection of this application.

Claims

1. A melt impact molding method for controlling carbides in alloy ingots, The steps include: preparing raw materials according to the chemical elemental composition of high-carbon high-alloy steel, and smelting them to obtain high-carbon high-alloy molten steel; The process involves overheating the aforementioned high-carbon high-alloy molten steel to a temperature range 50 to 100°C above its melting point to obtain a high-carbon high-alloy molten metal, depositing the high-carbon high-alloy molten metal at a rate of 30 to 160 g / s into a pre-set water-cooled copper mold via an inert gas, and solidifying and molding it to obtain a high-carbon high-alloy ingot. A melt impact molding method for controlling carbides in an alloy ingot, characterized by comprising the step of subjecting the high-carbon high-alloy ingot to a heat treatment process.

2. A melt impact molding method for controlling carbides in an alloy ingot according to claim 1, characterized in that the chemical elemental composition of the high-carbon high-alloy steel is, in weight percent, C: 1.5-2.5%, W: 2.5-10%, Mo: 3-7%, Cr: 4-6%, V: 2-10%, Si: 0.3-0.6%, Mn: 0.3-0.8%, and the remainder Fe.

3. The heat treatment process comprises sequentially performing high-temperature solid solution, low-temperature interrupted quenching, and tempering treatments, wherein the high-temperature solid solution is held at 900 to 1050°C for 15 to 60 minutes, the low-temperature interrupted quenching is held at 700 to 860°C for 1 to 2 hours, and the tempering treatment is held at 520 to 580°C for 3 to 4 hours, characterized in that it is a melt impact molding method for controlling carbides in an alloy ingot according to claim 1.

4. A melt impact molding method for controlling carbides in an alloy ingot according to claim 3, characterized in that, after high-temperature solid solution is completed, the alloy is oil-quenched to room temperature, then low-temperature interrupted quenching is performed, and / or, after low-temperature interrupted quenching is completed, the alloy is water-quenched to the martensitic transformation point, oil-quenched to room temperature, and then tempered.

5. A melt impact molding method for controlling carbides in an alloy ingot according to claim 1, characterized in that the superheating treatment method includes evacuating a chamber containing high-carbon high-alloy molten steel to a vacuum of 100 to 400 Pa, filling it with an inert gas for protection, and then heating the high-carbon high-alloy molten steel to obtain high-carbon high-alloy molten metal.

6. A melt impact molding method for controlling carbides in an alloy ingot according to claim 1 or 5, characterized by performing overheating treatment by a coil heating method.

7. A melt impact molding method for controlling carbides in an alloy ingot according to claim 5, characterized in that the molten metal deposition method includes filling with an inert gas for protection, heating high-carbon high-alloy molten steel to obtain high-carbon high-alloy molten metal, and then continuing to fill with an inert gas to promote injection of the high-carbon high-alloy molten metal into an external chamber.

8. The melt impact molding method for controlling carbides in an alloy ingot according to claim 1 or 7, characterized in that the high-carbon high-alloy molten metal is deposited under the action of a pressure difference, the pressure difference being 0.05 to 0.25 MPa.

9. A melt impact molding method for controlling carbides in an alloy ingot according to claim 1 or 7, characterized in that the distance between the nozzle outlet of the chamber where the high-carbon high-alloy molten metal is located and the water-cooled copper mold is 11 to 20 cm, and / or the water outlet temperature of the water-cooled copper mold is 30 to 45°C.

10. The melt impact molding method for controlling carbides in an alloy ingot according to claim 9, characterized in that the nozzle outlet shape is either a round hole type or a slit type, and all nozzles are arranged in an array.

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