Spray-formed wear and corrosion resistant dual strengthened phase precipitation hardened high speed steel

Abstract

The application discloses a spray forming wear-resistant and corrosion-resistant double-strengthening-phase precipitation hardening high-speed steel, which comprises the following components in percentage by mass: C: 0.2%-2.6%; Si: 0%-0.4%; Cr: 5.0%-15.0%; Co: 10.0%-30.0%; Ni: 0%-2.0%; (1.39Co+1.4Ni): 15.0% or more; V: 0%-8.0%; W: 0%-5.0%; Mo: 8%-20.0%; (Mo+W / 2): 10.0%-22.0%; and the balance of iron and impurities, wherein the steel is a double-strengthening-phase precipitation hardening high-speed steel, the strengthening phase comprises intermetallic compound (IMC) mu phase, MC carbide and (Cr, Fe) C type carbide, the mu phase is (Fe, Co) 7 (Mo+W / 2) 6 type, and the type of the MC carbide is V(C, N) type. The mu phase and the carbide of the prepared precipitation hardening high-speed steel are small in size and uniform in distribution, and the prepared precipitation hardening high-speed steel has excellent comprehensive performance, especially outstanding wear resistance and corrosion resistance, and can meet the requirements of different working conditions. The spray forming process is adopted in the application, and the spray forming process has the advantages of low cost and fast process compared with the powder metallurgy process.

Description

TECHNICAL FIELD

[0001] The present application relates to a precipitation hardening high speed steel, in particular to a spray forming wear and corrosion resistant double strengthening phase precipitation hardening high speed steel. BACKGROUND

[0002] The precipitation hardening steel is a carbon-free ferritic martensitic precipitation hardening tool alloy, which is a new type of ultra-high strength steel developed in recent years. This type of steel has good grindability and temper resistance, good dimensional stability, and is widely used to manufacture high-speed cutting tools for difficult-to-machine materials.

[0003] The hardening effect of the precipitation hardening steel is due to the intermetallic compound (IMC) particles precipitated during aging, which can improve the hardness and temper resistance of the precipitation hardening high speed steel. Moreover, the wear resistance of the steel depends on the hardness of the matrix and the content, morphology and particle size distribution of the hard second phase precipitated in the steel.

[0004] At present, the precipitation hardening steel is prepared by powder metallurgy process, which can solve the problem of element segregation and obtain uniform microstructure. Compared with the traditional casting and forging process, the powder metallurgy process has been greatly improved, but the powder metallurgy process is complex, long and high in cost, and the wear resistance and corrosion resistance of the existing precipitation hardening steel are difficult to meet the demand. SUMMARY

[0005] Therefore, the present application provides a spray forming wear and corrosion resistant double strengthening phase precipitation hardening high speed steel with good microstructure and excellent performance.

[0006] To achieve the above purpose, the technical scheme of the present application is as follows:

[0007] A spray forming wear and corrosion resistant double strengthening phase precipitation hardening high speed steel, characterized in that the steel comprises the following chemical components in mass percentage:

[0008] C: 1.0%-2.6%;

[0009] Si: 0%-0.4%;

[0010] Cr: 5.0%-15.0%;

[0011] V: 0-8.0%;

[0012] Co: 10%-30.0%;

[0013] W: 0%-5.0%;

[0014] Mo: 8%-20.0%;

[0015] (Mo+W / 2): 10.0%-22.0%;

[0016] Balance is iron and impurities;

[0017] And, the strengthening phase in the precipitation hardening high speed steel includes intermetallic compound (i.e. IMC phase) μ phase, MC carbide and (Cr, Fe) C type carbide, wherein the μ phase is (Fe, Co) 7 (Mo + W / 2) 6 type, and the MC carbide is V (C, N) type.

[0018] The present application promotes the nucleation and refinement of the strengthening phase of the precipitation hardening high speed steel under the spray forming process by the design of alloy composition, thereby improving the wear resistance and corrosion resistance of the precipitation hardening steel.

[0019] The role of Co (cobalt) is to dissolve in the matrix, so that the alloy becomes a martensitic steel, thereby improving the hardness and strength of the alloy by one level, and the increase of the Co content will appropriately reduce the toughness of the steel, and the Co element content range in the present application is 10.0%-30.0%, preferably 10.0%-28.0%.

[0020] Ni (nickel) can replace Co, and can also improve the thermal plasticity of the steel and increase the hardenability, but it can reduce the Ac1 point, thereby reducing the Ms point, so that the annealing hardness of the steel is significantly increased, the residual austenite content and stability are increased, and therefore the Ni element content range in the present application is 0%-2.0%, preferably 0.5%-1.8%.

[0021] The melting point of W (tungsten) is high, which increases the strength and tempering stability of the steel, the high temperature creep resistance, and the resistance to temper softening of the steel, so that the surface layer of the steel is less heated and the hardness is less reduced during processing and use, and the W element content range in the present application is 0%-5.0%, preferably 0%-3.0%.

[0022] The role of Mo (molybdenum) is the same as W, and the price of Mo is lower than that of W, and a proper amount of Mo is added in the present application to replace W, but it should be noted that the higher the Mo content, the higher the μ phase precipitation temperature, and the larger the μ phase particle size, and in order to ensure that the μ phase has small particle size, the Mo element content range in the present application is 8.0%-20.0%, preferably 13.5%-18.0%.

[0023] A small amount of C (carbon) is added to the steel, part of which is dissolved in the matrix to improve the strength of the matrix, and the other part of C is combined with the carbide forming element to improve the wear resistance of the material, and the C content is not less than 0.2% to ensure that the carbide forming element can participate in the precipitation of the carbide to form a double strengthening phase mechanism; at the same time, attention should be paid to the fact that the C content should not exceed 2.6%, so as to avoid excessive C dissolved in the matrix leading to a decrease in toughness, and within the above C content range of 1.0%-2.6%, the preferred range is 1.1%-2.5%, which can obtain good cooperation of wear resistance and toughness.

[0024] V (vanadium) as a strong carbide forming element, the main role is to form MC type carbide with the steel, improve the wear resistance of steel, in order to ensure that the steel is precipitated μ phase and MC carbide double phase strengthening mechanism, and ensure the grindability of steel, the content of V element in the present application is 0%-8.0%, preferably 0%-7.04%.

[0025] Cr (chromium) is added to the steel, one is to coarsen the particles, so that the red hardness is reduced, and the processability is improved; on the other hand, part of Cr is solid-solved in the matrix, which can improve the corrosion resistance and hardenability of the steel. In the present application, the content of Cr element is 5.0%-15.0%, preferably 5.0%-14.5%.

[0026] Si (silicon) is not a carbide forming element, but is used as a deoxidizer and matrix strengthening element, which can improve the strength and hardness of the steel, but too much Si will reduce the plasticity and toughness of the matrix. The Si content in the present application is controlled to be less than 0.4%, and preferably ≤0.32%.

[0027] As a limitation of the above-mentioned manner, the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel comprises the following chemical components by mass percentage:

[0028] C: 1.1%-2.5%;

[0029] Si: 0%-0.32%;

[0030] Co: 10.0%-28.0%;

[0031] Cr: 5.0%-14.5%;

[0032] Ni: 0.5%-1.8%;

[0033] (1.39Co+1.4Ni)≥16.0%;

[0034] V: 0%-7.04%;

[0035] W: 0%-3.0%;

[0036] Mo: 13.5%-18.0%;

[0037] (Mo+W / 2): 14.0%-22.0%;

[0038] The balance is iron and impurities.

[0039] In order to achieve better comprehensive performance, the content of each chemical component in the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel should be controlled within the required range.

[0040] Further, at least 80% volume fraction of the mu phase has at least 80% volume fraction of particle size ≤1.5 μm, the maximum particle size of the mu phase is not more than 7.0 μm, and the volume fraction of the mu phase in the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel is 10-20%.

[0041] Further, at least 80% volume fraction of the mu phase has at least 80% volume fraction of particle size ≤1.5 μm, the maximum particle size of the mu phase is not more than 7.0 μm, and the volume fraction of the mu phase in the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel is 10-20%.

[0042] Further, at least 80% volume fraction of the mu phase has at least 80% volume fraction of particle size ≤1.5 μm, the maximum particle size of the mu phase is not more than 7.0 μm, and the volume fraction of the mu phase in the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel is 10-20%.

[0043] Further, at least 80% volume fraction of the mu phase has at least 80% volume fraction of particle size ≤1.5 μm, the maximum particle size of the mu phase is not more than 7.0 μm, and the volume fraction of the mu phase in the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel is 10-20%.

[0044] The present application also provides a preparation method of the spray-formed wear-resistant and corrosion-resistant double-strengthening phase precipitation-hardened high-speed steel as described above, and the preparation method comprises the following steps:

[0045] a. preparing a liquid steel of the precipitation-hardened steel according to the chemical composition requirements and transferring the liquid steel to a ladle;

[0046] b. maintaining the superheat of the liquid steel by heating the protective slag covering the upper surface of the liquid steel in the ladle, and stirring the liquid steel by introducing inert gas at the bottom of the ladle;

[0047] c. flowing the liquid steel into a preheated tundish through a flow guide pipe at the bottom of the ladle at a stable flow rate, and applying protective slag to the upper surface of the liquid steel when the liquid steel enters the tundish and covers the lower end surface of the flow guide pipe;

[0048] d. continuously compensating and heating the tundish to maintain the superheat of the liquid steel;

[0049] e. atomizing and depositing the liquid steel from the tundish into a spray deposition chamber using inert gas, and completing the spray deposition to obtain a spray deposition ingot under a stable outlet pressure; maintaining the temperature and flow rate of the liquid steel stable during the spray deposition process, slowly lowering the spray deposition receiving disc while rotating horizontally, and keeping the lowering speed of the spray deposition receiving disc consistent with the growth speed of the spray deposition ingot to keep the height of the upper end surface of the spray deposition ingot constant; and controlling the gas inlet and outlet flow rates to maintain the inert gas protective atmosphere in the spray deposition chamber;

[0050] f, the spray deposition ingot is transferred to a protective atmosphere furnace for annealing or directly transferred to a hot forging breakdown process step.

[0051] g, homogenization treatment is carried out by using a chamber furnace, and the spray deposition ingot is forged to break down after being discharged by using multiple heating times and small deformation, to obtain a precipitation hardening high speed steel bar.

[0052] In the spray forming process, the whole process is protected to control the mu phase morphology and optimize the performance of the precipitation hardening high speed steel.

[0053] The protective slag of the ladle has the functions of air insulation and electric heating. Inert gas is introduced into the bottom of the ladle through the air hole, so that the temperature of the molten steel at different positions in the ladle is balanced, and the floating and removal of harmful inclusions are accelerated. The flow guide pipe at the bottom of the ladle plays a flow guiding role on the molten steel, reduces the turbulence generated during the flow of the molten steel, avoids slag entrapment or reduces the inclusions entering the next process, and on the other hand, avoids direct contact of the molten steel with air, preventing the continuous increase of oxygen content in the molten steel; the protective slag of the tundish prevents the molten steel flowing through the tundish from directly contacting with air, and reduces the increase of oxygen content in the molten steel.

[0054] The tundish is preheated before the molten steel enters the tundish, which can prevent local condensation of the molten steel when it enters the tundish or cause the second phase to precipitate in advance; the gas inlet and outlet flow of the spray deposition process is controlled to maintain the protective atmosphere of the inert gas in the spray deposition chamber, which protects the spray deposition ingot.

[0055] The precipitation hardening high speed steel in the application is prepared by the spray forming process, which has advantages in reducing the overall cost of the alloy, simplifying the process flow compared with the powder metallurgy process. In addition, the mu phase and carbide in the spray forming wear-resistant and corrosion-resistant double-strengthening phase precipitation hardening high speed steel of the application are small and uniform, which has excellent mechanical properties, especially high wear resistance and corrosion resistance, and the hardness after solid solution and aging treatment reaches 64HRC, which is suitable for use in working conditions with hard particles and corrosive media. BRIEF DESCRIPTION OF DRAWINGS

[0056] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0057] Figure 1 The microstructure diagram of the precipitation hardening high speed steel prepared in example 1 of the application;

[0058] Figure 2 The microstructure diagram of the precipitation hardening high speed steel prepared in example 2 of the application;

[0059] Figure 3 The microstructure diagram of the precipitation hardening high speed steel prepared in example 5 of the application;

[0060] Figure 4 Microstructure of the precipitation hardened high speed steel prepared for Example 6 of the present application;

[0061] Figure 5 Microstructure of the precipitation hardened high speed steel prepared for Example 7 of the present application;

[0062] Figure 6 Microstructure of the precipitation hardened high speed steel prepared for Example 8 of the present application;

[0063] Figure 7 Microstructure of the electroslag process high speed steel prepared for Comparative Example A of the present application;

[0064] Figure 8 Microstructure of the powder metallurgy process corrosion resistant high speed steel prepared for Comparative Example B of the present application. DETAILED DESCRIPTION

[0065] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0066] The present application relates to a group of spray formed wear and corrosion resistant dual strengthened phase precipitation hardened high speed steels, which comprises the following chemical components in percentage by mass: C: 1.0%-2.6%; Si: 0%-0.4%; Cr: 5.0%-15.0%; Co: 10.0%-30.0%; Ni: 0%-2.0%; (1.39Co+1.4Ni)≥15.0%; V: 0%-8.0%; W: 0%-5.0%; Mo: 8.0%-20.0%; (Mo+W / 2): 10.0%-22.0%; and the balance being iron and impurities.

[0067] As a preferred, the precipitation hardened high speed steel of the present application comprises the following chemical components in percentage by mass: C: 1.1%-2.5%; Si: 0%-0.32%; Co: 10.0%-28.0%; Cr: 5.0%-14.5%; Ni: 0.5%-1.8%; (1.39Co+1.4Ni)≥16.0%; V: 0%-7.04%; W: 0%-3.0%; Mo: 13.5%-18.0%; (Mo+W / 2): 14.0%-22.0%; and the balance being iron and impurities. The precipitation hardened high speed steel with the above components used in the present application can obtain ideal structure and excellent performance to meet the requirements.

[0068] Secondly, the present application also relates to a method for preparing the above-mentioned precipitation hardening high speed steel. Due to the high alloy content, if the traditional ingot or electroslag process is used for preparation, segregation is prone to occur due to slow solidification speed, resulting in performance decline. The powder metallurgy process is long and high in cost. In the premise of ensuring that the prepared precipitation hardening high speed steel ingot is uniform in composition and organization, fine in precipitated phase and high in purity, the spray forming process is used to replace the powder metallurgy process to prepare the steel ingot, and then the required rod product is obtained through forging.

[0069] Specifically, the preparation method of the present application comprises the following steps:

[0070] s1. The molten steel of the present application is loaded into a spray forming melting ladle, and the molten steel loading weight is 3.5 tons;

[0071] s1.1. The protective slag covering the upper surface of the molten steel in the ladle is heated by electric heating with a graphite electrode, argon is introduced into the bottom of the ladle to stir the molten steel, and the molten steel is opened when the superheat reaches 100-150℃.

[0072] s1.2. The molten steel is flowed into the tundish preheated to 800-1200℃ through the flow guide pipe at the bottom of the ladle at a flow rate of 100Kg / min-200Kg / min, and the protective slag is applied when the molten steel enters the tundish and covers the lower end surface of the flow guide pipe.

[0073] s1.3. The tundish is continuously compensated and heated during the spray deposition process, and the superheat of the molten steel is maintained at 100-150℃.

[0074] s1.4. The molten steel enters the spray deposition chamber through the bottom of the tundish, the gas injection valve is opened, nitrogen gas is used as the gas medium for atomization deposition, the purity of the nitrogen gas is ≥99.999%, the oxygen content is ≤2ppm, and the outlet pressure of the gas nozzle is 1.0MPa-1.5MPa-. The molten steel is broken into semi-solid droplets under the action of nitrogen gas, and then mixed with gas to form an atomization cone. The droplets fly to the spray deposition receiving disc and slowly descend while rotating horizontally. The spray deposition receiving disc descending speed is consistent with the spray deposition ingot growth speed to keep the height of the upper end surface of the spray deposition ingot constant. Before and after the start of the spray deposition, the interior of the spray deposition chamber is continuously maintained in a protective nitrogen atmosphere, and the gas inlet and outlet flow rates are controlled during the deposition process.

[0075] s1.5. After the spray deposition is completed, a single ingot with a weight of more than 3 tons and a size of φ550mm is obtained. The spray deposition ingot is transferred to a protective atmosphere furnace for annealing, and then cooled in the furnace.

[0076] s2. Open the blank by forging

[0077] The spray deposition ingot is opened by small deformation amount in multiple heating times, and the deformation amount is between 5-20mm each time, the heating temperature is between 1170-1200℃, heating for 400min, a total of 4 heating times of forging, after opening, the pipe is annealed in time, the annealing temperature is 870-890℃, and finally the precipitation hardening high speed steel rod is obtained.

[0078] The spray forming wear-resistant and corrosion-resistant double-strengthening phase precipitation hardening high speed steel and its preparation will be further described below with specific preparation examples and comparative examples, and corresponding performance detection. The strengthening phase particle size and volume fraction, heat treatment hardness, wear resistance and corrosion resistance of the spray forming wear-resistant and corrosion-resistant double-strengthening phase precipitation hardening high speed steel involved in the application are verified, wherein the particle size and volume fraction of mu phase and carbide are analyzed based on the microstructure images obtained by scanning electron microscope, and the heat treatment hardness, wear resistance and corrosion resistance are tested according to GB / T 230.1, GB / T 12444, JB / T 7901 and GB / T 17899 respectively.

[0079] Nine kinds of precipitation hardening high speed steels with different component compositions are obtained by the above preparation method, and are compared with cast and forged tool steel (alloy A) and powder metallurgy tool steel (alloy B), and the results are as follows:

[0080] Table 1: Component composition comparison:

[0081] Alloy C Si Mn Cr Co Ni V W Mo Mo + W / 2 1.39 Co + 1.4 Ni Fe Example 1 1.09 0.32 - 5.88 16.03 1.03 6.22 0.01 15.62 15.62 22.72 Balance Example 2 1.30 0.34 - 5.57 14.95 1.14 6.40 0.01 16.02 16.02 22.38 Balance Example 3 1.09 0.32 - 5.88 16.03 1.03 6.22 2. 16.0 17.0 22.72 Balance Example 4 1.09 0.32 - 5.88 10.0 2.0 6.22 0.01 15.62 15.62 16.7 Balance Example 5 1.0 - - 5.0 10.0 2.0 - 5.0 8.0 10.5 16.7 Balance Example 6 2.60 0.4 - 15.0 30.0 - 8.0 - 20.0 20.0 41.7 Balance Example 7 1.10 - - 5.0 10.0 1.80 0 - 18.0 18.0 16.42 Balance Example 8 2.50 0.32 - 14.5 28.0 0.5 7.04 3.0 13.5 14.0 37.1 Balance Example 9 2.55 0.36 - 14.7 9.0 1.9 7.5 4.0 19 21.0 15.17 Balance Comparative Example A 1.09 0.33 0.31 3.84 7.95 0.13 1.11 1.47 9.35 10.08 11.23 Balance Comparative Example B 1.61 0.42 0.34 4.72 7.97 0.17 5.05 10.22 2.15 7.26 11.31 Balance

[0082] "-" in the table means that the element is not contained, or the content of the element is very small and is not analyzed.

[0083] (I) Microstructure analysis

[0084] Based on the microstructure images obtained by scanning electron microscope, Figures 1 to 6 are the microstructure diagrams of the prepared precipitation hardening steel forgings example 1, example 2, example 5, example 6, example 7, example 8, Figure 7 is the microstructure diagram of alloy A, Figure 8 is the microstructure diagram of alloy B.

[0085] Obviously, Figures 1 to 6 The grayish white hardening phase is distributed in the matrix in a fine and dispersed manner, which can significantly improve the wear resistance, toughness and service life of the material. Figure 7 and Figure 8 Contains two kinds of precipitates, one is bright white and large in size, and the other is grayish white and small in size.

[0086] The precipitate content and particle size of the high speed steels prepared in examples 1-9 and alloys A and B after heat treatment are compared as shown in table 2:

[0087] Table 2: Content and particle size of precipitated phase

[0088]

[0089]

[0090] The solid solution system of Examples 1 to 9 is 1190℃*30 minutes, and the aging system is 600℃*3 hours; the quenching system of Comparative Example A is 1160℃*15 minutes, and the tempering system is 550℃*1 hour*3 times; the quenching system of Comparative Example B is 1170℃*15 minutes, and the tempering system is 550℃*1 hour*3 times.

[0091] The precipitated phase analysis of the high speed steel prepared in Examples 1 to 9 in the application is carried out: it is detected that the precipitated phase in Examples 1 to 9 is mainly IMC and carbide, wherein the IMC is mainly μ phase, the type is (Fe, Co)7(Mo+W / 2)6, the carbide is divided into two types, MC type carbide and Cr-rich (Cr, Fe)C type carbide; it is detected that the strengthening phase in alloy A and alloy B is mainly Cr-rich (Cr, Fe)C type carbide, in addition, there is MC type carbide.

[0092] The volume fraction of μ phase of the precipitated hardening high speed steel in the application reaches 10%-20%, the particle size is small, most of the μ phase particle size is less than 1.5μm, and the maximum size is not more than 7.0μm. At the same time, another type of strengthening phase in the precipitated hardening steel in the application is carbide, wherein the MC carbide type is V(C, N) type, the volume fraction is 1%-5%, the particle size is small, most of the MC carbide particle size is less than 2.0μm; the (Cr, Fe)C type carbide is Cr-rich carbide, the volume fraction reaches 3%-10%, most of the (Cr, Fe)C type carbide size is 3.0-12.0μm, and the maximum (Cr, Fe)C type carbide size is not more than 15.0μm.

[0093] The MC type carbide in the alloy B prepared by the powder metallurgy process is the smallest, most of the MC type carbide is 0.5-1.5μm, the volume fraction is 2-6%, but the volume fraction of the (Cr, Fe)C type carbide with the size range of 3-12μm in the structure is more than that of the example. In the A alloy produced by the traditional electroslag process, the size of the MC type carbide is close to that of the example, but there are a large number of (Cr, Fe)C type carbides with the size range of 5-30μm in the structure, and the coarse carbide has the adverse effect of cutting the matrix.

[0094] (II) Hardness and wear resistance performance analysis after heat treatment

[0095] In order to verify the influence of the heat treatment system on the properties of the prepared precipitation hardening high speed steel, different solid solution temperatures and aging temperatures are set to heat treat the prepared rods.

[0096] The high speed steels prepared in Examples 1 to 9 and the alloys A and B are heat treated, and the obtained hardness and wear resistance are compared, as shown in Table 3.

[0097] Table 3: Comparison of mechanical properties

[0098]

[0099] As can be seen from the comparison data in Table 3, the hardness of the precipitation hardening steel of the present application can reach more than 64HRC, and at the same time, excellent wear resistance is exhibited, and in the use process, long-term high-strength wear can be tolerated, thereby greatly improving the service life of the material.

[0100] (Three) Corrosion resistance analysis

[0101] The alloys prepared in Examples 1 to 9 and the alloys A and B are immersed in a 5% HNO3+1% HCl solution at room temperature, and then the corrosion rate is measured. Then the polarization curve is measured in a 1% NaCl solution, and finally the self-corrosion potential is obtained, and the comparison of corrosion resistance is shown in Table 4.

[0102] Table 4: Comparison of corrosion resistance

[0103]

[0104]

[0105] As can be seen from the comparison data in Table 4, the precipitation hardening steel of the present application exhibits more excellent corrosion resistance, and according to the requirements of corrosion resistance in different application occasions, a suitable heat treatment system should be selected, and within a relatively wide heat treatment temperature range, the precipitation hardening high speed steel of the present application can have good strength and toughness and wear and corrosion resistance.

[0106] In addition, due to the limitation of the precipitated phase particle number statistical image analysis software, under the above implementation conditions, the precipitation hardening steel of the present application may have individual μ phase and carbide with a size exceeding the maximum size in the microstructure, but due to the extremely small number, it has no substantial effect on the toughness and other mechanical properties of the precipitation hardening steel, and thus can be ignored. There are many μ phases with smaller particles that cannot be identified by the analysis software, and the statistical results of volume fraction and particle size are only for comparison.

[0107] Because this invention uses a specific alloy composition design and is prepared using a spray forming process, it has the characteristics of a dual-phase strengthening phase of μ phase and carbide. Its precipitated phase has a small particle size and a large dispersion, and the tools and parts made have a longer service life. They can meet the needs of different types of applications and can be used to make (1) tools for cutting difficult-to-machine materials under high-speed cutting; (2) high-precision measuring tools; (3) corrosion-resistant parts, etc.

[0108] In summary, the spray-formed wear-resistant and corrosion-resistant dual-strengthened precipitation-hardening high-speed steel of the present invention possesses excellent comprehensive performance, especially good wear and corrosion resistance. Due to the characteristics of its alloy composition, its strengthening mechanism differs from that of traditional high-speed steel, resulting in a significantly better resistance to tempering softening than traditional high-speed steel and other tool steels. It also has high wear and corrosion resistance, and its preparation cost is lower than that of powder metallurgy. The precipitation-hardening high-speed steel of the present invention is characterized by high efficiency and low cost, and has good practicality.

[0109] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A spray-formed, wear-resistant, and corrosion-resistant dual-strength precipitation-hardening high-speed steel, characterized in that, Its chemical components, by mass percentage, include: C：1.0％-2.6％； Si: 0%-0.4%; Cr：5.0％-15.0％； Co: 10.0%-30.0%; Ni: 0%-2.0%; (1.39Co + 1.4Ni) ≥ 15.0%; V：0％-8.0％； W：0％-5.0％； Mo: 8.0%-20.0%; (Mo+W / 2): 10.0%-22.0%; The balance consists of iron and impurities; Furthermore, the precipitated phases in the spray-formed wear-resistant and corrosion-resistant dual-strengthened precipitation-hardening high-speed steel include intermetallic compound (IMC) μ phase, MC carbide and (Cr,Fe)C type carbide, wherein the μ phase is of type (Fe,Co)7(Mo+W / 2)6 and the MC carbide is of type V(C,N).

2. The spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel according to claim 1, characterized in that, Its chemical components, by mass percentage, include: C：1.1％-2.5％； Si: 0%-0.32%; Co: 10.0%-28.0%; Cr：5.0％-14.5％； Ni: 0.5%-1.8%; (1.39Co + 1.4Ni) ≥ 16.0%; V：0％-7.04％； W：0％-3.0％； Mo: 13.5%-18.0%; (Mo+W / 2): 14.0%-22.0%; The balance consists of iron and impurities.

3. The spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel according to claim 1 or 2, characterized in that: The μ phase, comprising at least 80% by volume, has a particle size ≤1.5 μm and a maximum particle size not exceeding 7.0 μm. The volume fraction of the μ phase in the spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel is 10-20%.

4. The spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel according to claim 1 or 2, characterized in that: At least 80% by volume of the MC carbide has a particle size ≤2.0 μm, and the maximum particle size of the MC carbide does not exceed 3.0 μm. The volume fraction of the MC carbide in the spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel is 1%-5%.

5. The spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel according to claim 1 or 2, characterized in that: The (Cr,Fe)C type carbide is a Cr-rich carbide.

6. The spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel according to claim 1 or 2, characterized in that: The particle size of the (Cr,Fe)C type carbide is 3.0-12.0 μm, with at least 80% by volume, and the maximum particle size of the (Cr,Fe)C type carbide is no more than 15.0 μm. The volume fraction of the (Cr,Fe)C type carbide in the spray-formed wear-resistant and corrosion-resistant dual-strength precipitation-hardening high-speed steel is 3%-10%.

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