High-manganese-steel-based steel bond alloy and preparation method thereof

Abstract

The invention provides a high-manganese-steel-based steel bond alloy and a preparation method thereof, and belongs to the technical field of hard alloys. The high-manganese-steel-based steel bonded alloy comprises titanium carbide, iron powder, ferromanganese, molybdenum powder and nickel powder. The iron powder comprises reduced iron powder and carbonyl iron powder, and the mass ratio of the reduced iron powder to the carbonyl iron powder is (1.25-1): 1. By reasonably matching the reduced iron powder and the carbonyl iron powder and utilizing different particle size characteristics and forming performance of the reduced iron powder and the carbonyl iron powder, the compactness and the mechanical performance of the steel-bonded alloy can be effectively improved; titanium carbide serves as a hard phase to endow the material with excellent wear resistance, ferromanganese can improve the hardenability and toughness of a matrix, molybdenum powder and nickel powder further optimize the strength and hardness of the alloy, and therefore the high-manganese-steel-based steel-bonded alloy with excellent comprehensive performance is prepared and can be widely applied to the fields of wear-resistant parts and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cemented carbide, in particular to a high manganese steel-based steel bond and a preparation method thereof. BACKGROUND

[0002] The high manganese steel-based steel bond (hereinafter referred to as steel bond) is a high-life die material and engineering material produced by powder metallurgy method with steel as a base body and tungsten carbide, titanium carbide and the like as hard phases, which is between cemented carbide and alloy tool steel, die steel and high-speed steel. The ratio of the steel bond steel base body binder phase and the hard phase is quite extensive, which determines that it has the following excellent performances: 1) extensive process performance, mainly forgeability and machinability as well as heat treatability and weldability. 2) good physical and mechanical properties, mainly in the form of wear resistance comparable to high cobalt cemented carbide; higher rigidity, elastic modulus, bending strength and compressive strength than steel; higher toughness than cemented carbide; good self-lubricating property and high damping characteristics, etc. 3) excellent chemical stability, such as high temperature resistance, oxidation resistance, resistance to corrosion of various media, etc. Due to the above excellent comprehensive performance of the steel bond, it occupies an important position in die materials, wear-resistant parts, high-temperature-resistant and corrosion-resistant components, etc., and is widely used in metal processing, hardware electronics, automobiles, machinery, metallurgy, chemical industry, shipbuilding, aerospace and nuclear industry, etc. and achieves good results. Compared with alloy tool steel, die steel and high-speed steel, the die life of the steel bond can be greatly improved by ten times, and the economic benefit is also very significant. In the traditional high manganese steel-based steel-bonded cemented carbide represented by TM52, the hardness is generally 60-62HRC, and the impact toughness is 6-8J / cm 2 . The customer generally requires the product hardness to be 64HRC or even higher, but when the hardness is increased, the impact toughness of the product is often reduced, and it is difficult to meet all the needs of the customer in terms of hardness and toughness. SUMMARY

[0003] The present application is made in view of the problem that the hardness and toughness of the existing high manganese steel-based steel-bonded cemented carbide are difficult to be considered, and the purpose is to provide a high manganese steel-based steel bond and a preparation method thereof, which appropriately improves the hardness and impact toughness of the product.

[0004] Specifically, the present application provides a high manganese steel-based steel bond, and the composition of the raw materials of the high manganese steel-based steel bond includes titanium carbide, iron powder, manganese iron, molybdenum powder and nickel powder. The iron powder includes reduced iron powder and carbonyl iron powder, and the mass ratio of the reduced iron powder and the carbonyl iron powder is 1.25-1:1.

[0005] Further, the carbide titanium has a particle size of 5 microns or less; and the reduced iron has a particle size of 15-25 microns.

[0006] Further, the titanium carbide has a mass of 50-55% of the total mass of the alloy raw material.

[0007] Further, the manganese iron has a mass of 10-15% of the total mass of the alloy raw material.

[0008] Further, the iron powder has a mass of 25-35% of the total mass of the alloy raw material.

[0009] Further, the molybdenum powder has a mass of 0.8-1.5% of the total mass of the alloy raw material. The nickel powder has a mass of 1.8-2.5% of the total mass of the alloy raw material.

[0010] Further, the high manganese steel-based steel joint alloy substrate has a carbon content of 1.3-1.6%.

[0011] The second aspect of the application provides a preparation method of a high manganese steel-based steel joint alloy, comprising the following steps: S1. Mixing titanium carbide, iron powder, manganese iron, molybdenum powder, and nickel powder, and then spray drying to form a mixture; S2. After the mixed material is pressed into a compact, the compact is subjected to dewaxing and sintering; S3. After sintering, cooling to room temperature under a micro-positive pressure condition.

[0012] Further, the dewaxing and sintering in step S2 are performed by using a vacuum furnace or a dewaxing and sintering integrated furnace.

[0013] Further, the dewaxing in step S2 is performed under vacuum or hydrogen atmosphere, and the sintering is performed by vacuum sintering at a temperature of 1380-1400 DEG C for 30-120 minutes.

[0014] Further, the vacuum degree in the furnace during the dewaxing and sintering in step S2 is controlled to be less than or equal to 0.4 mbar.

[0015] The application has the following beneficial effects: The iron powder of the present application includes reduced iron powder and carbonyl iron powder, wherein the particle size of the carbonyl iron powder is less than or equal to 5 microns, the particle size of the reduced iron powder is 15-25 microns, and the mass ratio of the reduced iron powder to the carbonyl iron powder is set to 1.25-1:1. The finer carbonyl iron powder can fill the gaps between the coarser reduced iron powder particles, thereby significantly increasing the bulk density of the powder and reducing the pores that can be generated during subsequent sintering. At the same time, the fine particle size of the carbonyl iron powder has a larger specific surface area and higher activity, which helps to promote atomic diffusion and dissolution during sintering, enhances the bonding strength between the matrix and the hard phase, and thus has a positive effect on the hardness and toughness of the alloy. The relatively coarse particle size of the reduced iron powder, as the main component of the iron powder, helps to ensure that the mixture has a certain flowability during pressing, facilitating press forming and providing the alloy with a basic iron matrix composition. Through the combination of these two types of iron powder with specific proportions and particle sizes, the microstructure of the alloy can be optimized, laying the foundation for achieving excellent comprehensive mechanical properties.

[0016] The present application sets the mass proportion of titanium carbide to 50-55%, which is higher than that of traditional TM52. A higher content of titanium carbide hard phase as a skeleton can significantly improve the overall hardness and wear resistance of the alloy. The mass proportion of manganese iron is controlled to be 10-15%, and the increased manganese element helps to strengthen the matrix and improve the toughness and processing performance of the matrix, and can also form stable carbides with carbon, further optimizing the comprehensive mechanical properties of the alloy. In addition, by precisely controlling the carbon content of the alloy matrix to be 1.3-1.6%, a higher carbon content can ensure the formation of sufficient carbides in the matrix, improve the hardness, and cooperate with elements such as manganese to ensure that the matrix has a good strength and toughness balance.

[0017] The present application improves the hardness and impact toughness of the high manganese steel-based steel bond alloy by optimizing the selection and ratio of raw materials. The hardness reaches 63-66HRC, and the impact toughness reaches 7-9J / cm 2 . BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the drawings, and other drawings can also be obtained according to the structures shown in the drawings without creative labor for those skilled in the art.

[0019] Figure 1 The product metallographic chart in Example 1 is shown in Figure 1. Figure 2 The product metallographic chart in Comparative Example 1 is shown in Figure 2.

[0020] The purposes, functional features and advantages of the drawings will be further described with reference to the drawings and embodiments. DETAILED DESCRIPTION

[0021] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be described and explained in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. Based on the embodiments provided by the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0022] Obviously, the following description is only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can also be applied to other similar scenarios without creative labor. In addition, it can also be understood that although the efforts made in this development process can be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacture or production changes based on the technical content disclosed in the present application are only routine technical means and should not be understood as insufficient disclosure of the present application.

[0023] The first aspect of the present application provides a high manganese steel-based steel alloy, the composition of the high manganese steel-based steel alloy includes titanium carbide, iron powder, manganese iron, molybdenum powder, nickel powder; the iron powder includes reduced iron powder and carbonyl iron powder, and the mass ratio of the reduced iron powder and the carbonyl iron powder is 1.25-1:1.

[0024] Preferably, the mass ratio of the reduced iron powder and the carbonyl iron powder can be 1:1, 1.05:1, 1.1:1, 1.15:1, 1.2:1, 1.25:1, etc. If the mass ratio of the reduced iron powder and the carbonyl iron powder is higher than 1.25:1, the proportion of the relatively coarse reduced iron powder is too large, the filling effect of the fine-grained carbonyl iron powder is weakened, the powder bulk density is difficult to effectively improve, which may lead to a decrease in the alloy density after sintering, affecting the hardness and toughness; if the mass ratio is lower than 1:1, the content of the too fine carbonyl iron powder is too high, which will make the flowability of the mixed material poor, and problems such as uneven green density and increased defects are prone to occur during the pressing forming process, which is also not conducive to obtaining high-performance alloys.

[0025] In the present embodiment, the particle size of the carbonyl iron powder is ≤5 μm, such a fine particle size makes it have very high activity, can quickly diffuse and react with other components during sintering, and promote the combination of the matrix and the hard phase; the particle size of the reduced iron powder is 15-25 μm, the reduced iron powder in this particle size range can not only ensure a certain powder flowability, facilitating the forming operation, but also form a good particle size gradation with the carbonyl iron powder, together improving the bulk characteristics of the powder system.

[0026] In the embodiment, the mass of titanium carbide accounts for 50-55% of the total mass of the alloy raw material. For example, it can be any value of 50%, 51%, 52%, 53%, 54%, or 55%. When the mass of titanium carbide accounts for less than 50%, the content of hard phase is insufficient, the overall hardness and wear resistance of the alloy are not obviously improved, and it is difficult to meet the use requirement of high hardness. When the mass accounts for more than 55%, too much hard phase can increase the brittleness of the alloy and reduce the impact toughness, and also increase the cost of raw materials.

[0027] In the embodiment, the mass of manganese iron accounts for 10-15% of the total mass of the alloy raw material, for example, it can be 10%, 11%, 12%, 13%, 14%, or 15%. As an important alloying element, manganese can significantly improve the hardenability and toughness of the matrix. When the content of manganese iron is less than 10%, the effect of strengthening the matrix and improving the toughness is not good. If it is higher than 15%, too many brittle phases can appear in the alloy, which adversely affects the toughness and can also affect the processing performance of the alloy.

[0028] In the embodiment, the mass of iron powder accounts for 25-35% of the total mass of the alloy raw material, and specific values such as 25%, 27%, 30%, 32%, and 35% can be selected. As the main component of the matrix, the content of iron powder directly affects the performance of the matrix of the alloy. If the content is too low, it cannot form a continuous and complete matrix structure, and it is difficult to effectively bond the hard phase. If the content is too high, the proportion of the hard phase will be relatively reduced, and the hardness and wear resistance of the alloy cannot meet the expected requirements.

[0029] In the embodiment, the mass of molybdenum powder accounts for 0.8-1.5% of the total mass of the alloy raw material, such as 0.8%, 1.0%, 1.2%, 1.4%, or 1.5%. Molybdenum can refine the grain and improve the hardenability and thermal stability of the alloy. A small amount of molybdenum powder can positively affect the performance of the alloy. If the content is too high, the cost will increase and the brittleness of the alloy can increase.

[0030] The mass of nickel powder accounts for 1.8-2.5% of the total mass of the alloy raw material, for example, 1.8%, 2.0%, 2.2%, 2.4%, or 2.5%. Nickel can significantly improve the toughness and strength of the matrix and improve the overall mechanical properties of the alloy. The content needs to be controlled within a reasonable range. Too little will not have a significant strengthening effect, and too much can reduce the hardness of the alloy.

[0031] In the present embodiment, the high manganese steel-based steel alloy substrate has a carbon content of 1.3-1.6%, such as 1.3%, 1.4%, 1.5%, or 1.6%. The carbon content of the substrate is one of the key factors affecting the performance of the alloy substrate. If the carbon content is too low, the amount of carbide in the substrate is insufficient, and the hardness is low. If the carbon content is too high, too much brittle carbide will be formed, resulting in a decrease in the toughness of the substrate. By accurately controlling the carbon content within this range, a good match between the hardness and toughness of the substrate can be achieved.

[0032] The second aspect of the present application provides a preparation method of a high manganese steel-based steel alloy, comprising the following steps: S1. mixing titanium carbide, iron powder, manganese iron, molybdenum powder, and nickel powder, and then spray drying to form a mixture; S2. using a vacuum furnace or a dewaxing and sintering integrated furnace to dewax and sinter the compacted substrate after the mixture is compacted; S3. cooling to room temperature under a micro-positive pressure condition after the sintering is completed.

[0033] In step S1, the raw materials are mixed and then spray dried to form a mixture. This method can make the raw materials more uniformly mixed, and at the same time, spherical particles with good fluidity and uniform composition are obtained, which is beneficial to subsequent compacting. In step S2, the dewaxing and sintering are performed using a vacuum furnace or a dewaxing and sintering integrated furnace. The vacuum degree in the furnace during the sintering process is controlled to be less than or equal to 0.4 mbar. The dewaxing process is performed in a vacuum or in a hydrogen atmosphere. Hydrogen not only acts as a protective atmosphere to prevent oxidation of the alloy, but also has a reducing effect to some extent, removing oxides that may exist on the surface of the raw materials and purifying the grain boundaries. In step S3, the alloy is cooled to room temperature under a micro-positive pressure condition. The micro-positive pressure environment helps to inhibit the infiltration of gas and the generation of pores during the cooling process, further ensuring the density of the alloy.

[0034] Embodiment The present disclosure is described in more detail by the following examples, which are merely illustrative and not limiting, as various modifications and variations can be apparent to those skilled in the art within the scope of the present disclosure. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight. Unless otherwise stated, all reagents used in the examples are available by conventional commercial routes or synthesized according to conventional methods and used directly without further purification. Unless otherwise stated, the instruments used in the examples are available by conventional commercial routes.

[0035] Example 1 A high manganese steel-based steel alloy and a preparation method thereof, comprising the following steps: (1) raw materials TiC 5.3kg, manganese iron 1.4kg, reduced iron powder (particle size 20μm) 1.5kg, carbonyl iron powder (particle size 5μm) 1.5kg, molybdenum powder 0.1kg, nickel powder 0.2kg, and additional carbon black 0.06kg (the carbon content of the matrix is controlled at 1.4%) are ball-mixed and then spray-dried to form a mixture; (2) the green compact of 10kg formed by pressing the high manganese steel-based steel bonding alloy mixture is loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen gas is used for dewaxing; (3) the high manganese steel-based steel bonding alloy green compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) after the sintering is completed, argon gas is filled to cool to room temperature.

[0036] The sintered product of this embodiment has the following performance test results: density 6.05g / cm 3 , hardness 64.3HRC, metallographic A04B02, bending strength 1920Mpa, and impact toughness 8.1J / cm 2 .

[0037] Example 2 A high manganese steel-based steel bonding alloy and a preparation method thereof, comprising the following steps: (1) raw materials TiC 5.3kg, manganese iron 1.4kg, reduced iron powder 1.66k, carbonyl iron powder 1.34kg, Mo powder 0.1kg, Ni powder 0.2kg, and additional carbon black 0.06kg (the carbon content of the matrix is controlled at 1.4%) are ball-mixed and then spray-dried to form a mixture; (2) the green compact of 10kg formed by pressing the high manganese steel-based steel bonding alloy mixture is loaded into a vacuum furnace for vacuum dewaxing and sintering; (3) the high manganese steel-based steel bonding alloy green compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) the high manganese steel-based steel bonding alloy green compact is sintered, and then cooled to room temperature in vacuum.

[0038] The sintered product of this embodiment has the following performance test results: density 6.04g / cm 3 , hardness 65.1HRC, metallographic A04B02, bending strength 1880Mpa, and impact toughness 7.6J / cm 2 .

[0039] Example 3 A high manganese steel-based steel bonding alloy and a preparation method thereof, comprising the following steps: (1) The raw materials TiC 5kg, manganese iron 1.4kg, reduced iron powder 1.65kg, carbonyl iron powder 1.65kg, Mo powder 0.1kg, Ni powder 0.2kg, and additional carbon black 0.062kg (the carbon content of the matrix is controlled at 1.4%) are ball-mixed and then spray-dried to form a mixture; (2) The high manganese steel-based steel bonding alloy mixture is pressed into a compact 10kg, which is loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen is used as the gas during dewaxing; (3) The high manganese steel-based steel bonding alloy compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) After the sintering of the high manganese steel-based steel bonding alloy compact is completed, argon is filled to a slight positive pressure and the compact is cooled to room temperature.

[0040] The sintered product of this embodiment has the following performance test results: density 6.09g / cm 3 , hardness 63.2HRC, metallographic A04B02, bending strength 1960Mpa, and impact toughness 8.4J / cm2.

[0041] Example 4 A high manganese steel-based steel bonding alloy and a preparation method thereof, comprising the following steps: (1) The raw materials TiC 5.5kg, manganese iron 1.4kg, reduced iron powder 1.4kg, carbonyl iron powder 1.4kg, Mo powder 0.1kg, Ni powder 0.2kg, and additional carbon black 0.057kg (the carbon content of the matrix is controlled at 1.4%) are ball-mixed and then spray-dried to form a mixture; (2) The high manganese steel-based steel bonding alloy mixture is pressed into a compact 10kg, which is loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen is used as the gas during dewaxing; (3) The high manganese steel-based steel bonding alloy compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) After the sintering of the high manganese steel-based steel bonding alloy compact is completed, argon is filled to a slight positive pressure and the compact is cooled to room temperature.

[0042] The sintered product of this embodiment has the following performance test results: density 6.00g / cm 3 , hardness 64.9HRC, metallographic A04B02, bending strength 1760Mpa, and impact toughness 7.4J / cm 2 .

[0043] Example 5 A high manganese steel-based steel bonding alloy and a preparation method thereof, comprising the following steps: (1) The raw materials TiC 5.3 kg, manganese iron 1.4 kg, reduced iron powder 1.5 kg, carbonyl iron powder 1.5 kg, Mo powder 0.1 kg, Ni powder 0.2 kg, and additional carbon black 0.055 kg (the matrix carbon content is controlled at 1.3%) are ball-mixed, and then spray-dried to form a mixed material; (2) The high-manganese steel-based steel bonding alloy mixed material is pressed into a compact 10 kg, which is loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen gas is used for dewaxing; (3) The high-manganese steel-based steel bonding alloy compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4 mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) After the sintering of the high-manganese steel-based steel bonding alloy compact is completed, argon gas is filled to a slight positive pressure, and then cooled to room temperature.

[0044] The sintered product of this embodiment has the following performance test results: density 6.04 g / cm 3 , hardness 64.1 HRC, metallography A04B02, bending strength 1880 Mpa, and impact toughness 8.0 J / cm 2 .

[0045] Example 6 A high-manganese steel-based steel bonding alloy and a preparation method thereof, comprising the following steps: (1) The raw materials TiC 5.3 kg, manganese iron 1.4 kg, reduced iron powder 1.5 kg, carbonyl iron powder 1.5 kg, Mo powder 0.1 kg, Ni powder 0.2 kg, and additional carbon black 0.069 kg (the matrix carbon content is controlled at 1.6%) are ball-mixed, and then spray-dried to form a mixed material; (2) The high-manganese steel-based steel bonding alloy mixed material is pressed into a compact 10 kg, which is loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen gas is used for dewaxing; (3) The high-manganese steel-based steel bonding alloy compact is sintered in vacuum, the vacuum degree in the furnace is ≤0.4 mbar, the sintering temperature is 1395℃, and the furnace is powered off after 90 minutes of heat preservation; (4) After the sintering of the high-manganese steel-based steel bonding alloy compact is completed, argon gas is filled to a slight positive pressure, and then cooled to room temperature.

[0046] The sintered product of this embodiment has the following performance test results: density 6.04 g / cm 3 , hardness 64.5 HRC, metallography A04B02, bending strength 1840 Mpa, and impact toughness 7.5 J / cm 2 .

[0047] Comparative Example 1 A traditional method for producing a TM52 high-manganese steel-based steel bonding alloy, comprising the following steps: (1) The raw materials for producing TM52 were mixed in a certain proportion: TiC 4.8 kg, manganese iron 1.1 kg, reduced iron powder 3.8 kg, Mo powder 0.1 kg, Ni powder 0.2 kg, and additional carbon black 0.04 kg, and then ball-mixed and spray-dried to form a mixture; (2) The compact of 10 kg formed by pressing the TM52 mixture was loaded into a dewaxing-sintering integrated furnace for dewaxing and sintering, and hydrogen was used as the gas during dewaxing; (3) The compact of the TM52 steel bond described above was sintered in a vacuum, with a vacuum degree in the furnace of ≤0.4 mbar, a sintering temperature of 1395°C, and a holding time of 90 minutes before power-off; (4) After sintering of the compact of the TM52 steel bond described above was completed, argon was filled to a slight positive pressure, and the compact was cooled to room temperature.

[0048] The sintered TM52 product of this example had the following performance test results: density 6.15 g / cm 3 , hardness 61.3 HRC, metallographic A04B04, bending strength 1820 MPa, and impact toughness 7.5 J / cm 2 . The metallographic chart of the product is shown in Figure 2 .

[0049] Analysis: The content of the hard phase titanium carbide in the TM52 steel bond of Comparative Example 1 was 48%, which was lower than the range of 50-55% in the examples of the present application, resulting in a hardness of only 61.3 HRC, which was significantly lower than the hardness level of 63.2-65.1 HRC in the examples, and the wear resistance improvement effect was not good. At the same time, the content of manganese iron was 11%, which was close to the lower limit of the range of 10-15% in the present application, but the content of iron powder was as high as 38%, which was far beyond the range of 25-35% in the present application. Too much iron powder increased the proportion of the matrix, further diluting the proportion of the hard phase, which was one of the important reasons for the low hardness. In addition, the metallographic result of Comparative Example 1 was A04B04, which was compared with A04B02 of the examples, indicating that there might be more pores or brittle phases in the structure, which was related to the raw material ratio and the bonding state of the matrix and the hard phase in the sintering process, and further affected the comprehensive mechanical properties.

[0050] Comparative Example 2 The traditional method for producing TM52 high-manganese steel bond includes the following steps: (1) The raw materials for producing TM52 were mixed in a certain proportion: TiC 4.8 kg, manganese iron 1.1 kg, reduced iron powder 3.8 kg, Mo powder 0.1 kg, Ni powder 0.2 kg, and additional carbon black 0.04 kg, and then ball-mixed and spray-dried to form a mixture; (2) TM52 mixture compaction after the compacts 10 kg, loaded into the vacuum furnace for dewaxing sintering, dewaxing for vacuum dewaxing; (3) the TM52 steel binder compacts in the sintering stage using vacuum sintering, furnace vacuum ≤ 0.4 mbar, to sintering temperature 1395 ℃, 90 minutes after the heat preservation power off; (4) the TM52 steel binder compacts sintering after the end of the vacuum cooling to room temperature.

[0051] TM52 products sintered in this example, the performance test results as follows: density 6.14 g / cm 3 , hardness 62.5 HRC, metallographic A04B04, bending strength 1750 Mpa, impact toughness 6.8 J / cm 2 .

[0052] Analysis: the comparative example 2 compared with the comparative example 1, except that the step (2) in the dewaxing way and step (4) cooling way is different, the raw material ratio, ball milling, spray drying, compaction and sintering temperature, holding time parameters are consistent. Comparative example 2 in the dewaxing stage using vacuum dewaxing, its dewaxing efficiency is much lower than hydrogen dewaxing, and will be more residual carbon in its matrix, thus leading to the hardness of the product after sintering is high, toughness is poor; And step (4) using vacuum cooling to room temperature, compared with the argon filled micro positive pressure cooling of comparative example 1, lack of protective gas inhibition of possible trace oxidation or gas penetration in the cooling process, thus adversely affect the performance. From the test results, its hardness 62.5 HRC, although slightly higher than the comparative example 1 of 61.3 HRC, but still lower than the example of the application, the bending strength 1750 Mpa and impact toughness 6.8 J / cm² are lower than the comparative example 1, indicating that different dewaxing and cooling way will affect the comprehensive mechanical properties of the alloy. The metallographic result is also A04B04, showing that the organization defect has not been improved.

[0053] Comparative example 3 A high manganese steel based steel binder and its preparation method, comprising the following steps: (1) the raw material titanium carbide 5.3 kg, manganese iron 1.4 kg, reduced iron powder (particle size 20 μm) 3 kg, molybdenum powder 0.1 kg, nickel powder 0.2 kg, additional carbon black 0.06 kg (matrix carbon content control in 1.4%), after ball milling, spray drying to prepare the mixture; (2) the high manganese steel based steel binder mixture compaction after the compacts 10 kg, loaded into the dewaxing sintering furnace for dewaxing sintering, the gas is hydrogen during dewaxing; (3) the high manganese steel based steel binder compacts in the sintering stage using vacuum sintering, furnace vacuum ≤ 0.4 mbar, sintering temperature 1395 ℃, 90 minutes after the heat preservation power off; (4) After sintering, argon is filled to micro-positive pressure and cooled to room temperature.

[0054] The sintered product of the embodiment is subjected to performance detection, and the results are as follows: density 6.04 g / cm 3 , hardness 64.1 HRC, metallography A04B04, bending strength 1740 Mpa, impact toughness 6.7 J / cm 2 .

[0055] Analysis: Compared with Example 1, the iron powder in Comparative Example 3 is also reduced iron powder, and no carbonyl iron powder is added, and the bending strength and impact toughness of the sintered product have a significant downward trend, which further shows that reasonable matching of iron powder of different particle sizes is beneficial to improving the comprehensive performance of the alloy.

[0056] In summary, by reasonably matching the reduced iron powder and the carbonyl iron powder, and utilizing the different particle size characteristics and forming properties of the two, the density and mechanical properties of the steel-based alloy can be effectively improved. The reduced iron powder has the characteristics of low cost and good fluidity, and can be used as the main component of the matrix skeleton; the carbonyl iron powder can uniformly fill the gap between the reduced iron powder particles due to its ultra-fine particle size and high activity, and can promote diffusion and densification during sintering. At the same time, titanium carbide as a hard phase endows the material with excellent wear resistance, manganese iron can improve the hardenability and toughness of the matrix, and molybdenum powder and nickel powder can further optimize the strength and hardness of the alloy, so as to prepare a high-manganese steel-based steel alloy with excellent comprehensive performance, which can be widely used in the field of wear-resistant parts and the like.

[0057] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solutions of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications of the embodiments that can be thought of by those skilled in the art, and other ways constructed by combining part of the components of the embodiments are also included in the scope of the present application.

Claims

1. A high-manganese steel-based steel alloy, characterized in that, The raw materials of the high-manganese steel-based steel bond include titanium carbide, iron powder, ferromanganese, molybdenum powder, and nickel powder. The iron powder includes reduced iron powder and carbonyl iron powder, and the mass ratio of the reduced iron powder to the carbonyl iron powder is 1.25-1:

1.

2. The high-manganese steel-based steel alloy according to claim 1, characterized in that, The carbonyl iron powder has a particle size ≤ 5 μm; the reduced iron powder has a particle size of 15-25 μm.

3. The high-manganese steel-based steel alloy according to claim 1, characterized in that, The titanium carbide accounts for 50-55% of the total mass of the alloy raw materials.

4. The high-manganese steel-based steel alloy according to claim 1, characterized in that, The ferromanganese accounts for 10-15% of the total mass of the alloy raw materials.

5. The high-manganese steel-based steel alloy according to claim 1, characterized in that, The iron powder accounts for 25-35% of the total mass of the alloy raw materials; And / or, the molybdenum powder accounts for 0.8-1.5% of the total mass of the alloy raw materials; And / or, the nickel powder accounts for 1.8-2.5% of the total mass of the alloy raw materials.

6. The high-manganese steel-based steel alloy according to claim 1, characterized in that, The carbon content of the high-manganese steel-based steel alloy matrix is ​​1.3-1.6%.

7. A method for preparing a high-manganese steel-based steel alloy, characterized in that, The method for preparing the high-manganese steel-based steel alloy according to any one of claims 1-6 comprises the following steps: S1. Titanium carbide, iron powder, ferromanganese, molybdenum powder, and nickel powder are mixed and then spray-dried to prepare a mixture; S2. Dewaxing and sintering the pressed compact after pressing the mixture; S3. After sintering, cool to room temperature under a slight positive pressure.

8. The method for preparing high-manganese steel-based steel alloy according to claim 7, characterized in that, In step S2, dewaxing and sintering are carried out in a vacuum furnace or an integrated dewaxing and sintering furnace.

9. The method for preparing high-manganese steel-based steel alloy according to claim 7, characterized in that, In step S2, dewaxing is carried out under hydrogen or vacuum atmosphere, and sintering is carried out under vacuum sintering at a temperature of 1380-1400℃ for 30-120 minutes.

10. The method for preparing high-manganese steel-based steel alloy according to claim 8, characterized in that, In step S2, the vacuum level inside the furnace during the dewaxing and sintering stage is controlled to be ≤0.4mbar.

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