Method for preparing powder high-speed steel billet, powder high-speed steel billet and application

Abstract

The invention discloses a method for preparing a powder high-speed steel billet, the powder high-speed steel billet and application, and relates to the technical field of advanced manufacturing of metal materials. The powder high-speed steel billet is prepared through the high-frequency induction hot pressing sintering method, rapid manufacturing of the powder high-speed steel billet can be achieved, and the performance of the obtained product can reach the product level of traditional hot isostatic pressing sintering. And compared with a traditional hot isostatic pressing preparation method, the technological process is simple, the period is short, preparation of a sheath is avoided, the cost can be reduced, and the safety can be improved. The density of the prepared powder high-speed steel can reach 98.5%, the microhardness reaches 365 Hv, the tensile strength and the yield strength reach 723 MPa and 687 MPa correspondingly, short-process and low-cost preparation of the powder high-speed steel billet can be achieved, and the obtained powder high-speed steel billet can be used for manufacturing hardware knives and scissors, mechanical molds and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced manufacturing of metal materials, and in particular to a method for preparing a powder high-speed steel billet, a powder high-speed steel billet and an application thereof. Background Art

[0002] Powder high-speed steel is a high-performance tool steel material with high alloy content prepared by powder metallurgy process. Compared with traditional molten high-speed steel, powder high-speed steel eliminates the macro-segregation of alloy components, and the carbides are small and evenly distributed. It has excellent comprehensive properties such as high hardness, high corrosion resistance, high red hardness, and high wear resistance. Therefore, it is widely used in processing equipment such as taps, drills, tools, and stamping dies. With the machinery manufacturing industry putting forward higher requirements for high-performance tool materials and the increase in market demand, powder metallurgy high-speed steel has accounted for about 10% of the annual output of high-speed steel.

[0003] At present, domestic and foreign manufacturers mainly use hot isostatic pressing (HIP) technology to produce powder high-speed steel billets, that is, using gas as the pressure medium and applying high temperature and high pressure at the same time to make the powder in the sleeve sinter and densify. The hot isostatic pressing process greatly reduces the sintering temperature of the powder due to the effect of high pressure, making the hot isostatic pressed powder high-speed steel have the advantages of fine grains, uniform carbide distribution, and high density. However, the cost of sleeve + hot isostatic pressing is high, the process flow is long, and there is a risk of "explosion" of the sleeve due to poor sealing of the sleeve.

[0004] Therefore, there is an urgent need to develop a simple and easy production process with a short process flow to improve production efficiency and reduce equipment costs.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing a powder high-speed steel billet, a powder high-speed steel billet and an application thereof, aiming to shorten the process flow and reduce the process cost while ensuring product performance.

[0007] The present invention is achieved in that:

[0008] In a first aspect, the present invention provides a method for preparing a powder high speed steel billet, comprising:

[0009] The raw material powder is filled into a mold, and placed in a high-frequency induction hot pressing sintering furnace to sequentially undergo a pre-pressing stage, a temperature and pressure increasing stage, a temperature and pressure maintaining stage, and a temperature and pressure reducing stage.

[0010] In an optional embodiment, during the temperature and pressure increase stage, the temperature is controlled to be increased to 1000° C.-1250° C., and the pressure is increased to 2 MPa-50 MPa;

[0011] Preferably, during the temperature and pressure increase stage, the temperature is controlled to be increased to 1000° C.-1100° C., and the pressure is increased to 30 MPa-50 MPa.

[0012] In an optional embodiment, during the temperature and pressure increase stage, the temperature increase rate is controlled to be 10°C / min-100°C / min, and the pressure increase rate is controlled to be 0.5MPa / min-20MPa / min;

[0013] Preferably, during the temperature and pressure increase stages, the temperature increase rate is controlled to be 80°C / min-100°C / min, and the pressure increase rate is controlled to be 0.5MPa / min-5MPa / min.

[0014] In an optional embodiment, during the heat preservation and pressure preservation stage, the heat preservation and pressure preservation time is controlled to be 10 min-120 min, preferably 10 min-60 min.

[0015] In an optional embodiment, during the temperature reduction and pressure reduction stage, the temperature reduction rate is controlled to be 5°C / min-100°C / min, and the pressure reduction rate is controlled to be 0.5MPa / min-20MPa / min;

[0016] Preferably, during the temperature reduction and pressure reduction stage, the temperature reduction rate is controlled to be 80°C / min-100°C / min, and the pressure reduction rate is controlled to be 0.5MPa / min-5MPa / min;

[0017] Preferably, demoulding is performed after the pressure is completely unloaded and the temperature drops to 15°C-30°C.

[0018] In an optional embodiment, during the pre-pressing stage, the pressure is controlled to be 2 MPa-30 MPa, and the processing time is 5 min-30 min.

[0019] In an optional embodiment, the raw material powder has a chromium content of 20%-22%, a molybdenum content of 1.0%-2.0%, a cobalt content of 1.0%-1.5%, a vanadium content of 0.6%-1.0%, a carbon content of 1.9%-2.2%, and the remainder is iron, by mass percentage;

[0020] Preferably, the raw material powder has a sphericity greater than 0.8.

[0021] In an optional embodiment, the raw material powder is divided into fine powder, medium powder and coarse powder according to the particle size range, the particle size range of the fine powder is 2μm-66μm, the particle size range of the medium powder is 5μm-209μm, and the particle size range of the coarse powder is 71μm-400μm;

[0022] Preferably, the raw material powder is medium powder.

[0023] In a second aspect, the present invention provides a powder high speed steel billet prepared by any one of the methods described in the aforementioned embodiments.

[0024] In a third aspect, the present invention further provides the use of the powder high-speed steel billet provided in the above embodiment in the preparation of hardware knives and scissors or mechanical molds.

[0025] The present invention has the following beneficial effects: the present invention adopts a high-frequency induction hot pressing sintering method to prepare a powder high-speed steel billet, which can realize rapid manufacturing of the powder high-speed steel billet, and the obtained product performance can reach the level of the product of the traditional hot isostatic pressing sintering. Compared with the traditional hot isostatic pressing preparation method, the process flow is simple, the cycle is short, and the preparation of the sheath is avoided, which can reduce costs and improve safety.

[0026] The density of the powder high-speed steel prepared by the present invention can reach 98.5%, the microhardness can reach 365Hv, the tensile strength and yield strength can reach 723MPa and 687MPa respectively, and the short process and low-cost preparation of powder high-speed steel billets can be realized. The obtained powder high-entropy steel billets can be used to manufacture hardware knives and scissors, mechanical molds, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a diagram of the device for high frequency induction heating sintering;

[0029] Figure 2 The particle size distribution of the three particle size powders used in the present invention;

[0030] Figure 3 This is a scanning electron microscope photo of the powder high speed steel billet prepared in Example 1;

[0031] Figure 4 The microstructure of the powder high speed steel prepared in Example 1 is shown in FIG. 1 ; (b) is an enlarged view of the red area in (a);

[0032] Figure 5 The fracture morphology of the powder high-speed steel prepared in Example 1; (a) represents the overall fracture morphology; (b) represents area 1 in (a); (c) represents area 2 in (a). DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0034] High frequency induction heated sintering (HFIHS) is a heating method that generates eddy currents in the powder under the action of high frequency alternating current through the inductor coil wound outside the die, thereby generating self-heating. Its working principle is as follows: Figure 1 Compared with the hot isostatic pressing process, it has higher energy utilization and work efficiency, can achieve short-time densification sintering, avoids the preparation of the package, can reduce costs and improve safety.

[0035] The traditional sintering process for preparing powder high-speed steel billets mostly uses heat radiation and heat conduction to heat, which has obvious temperature gradients and no self-heating of the powder. The sintering method provided in the embodiment of the present invention has self-heating, higher sintering efficiency, and impurities inside the powder can be melted by self-heating. In addition, the self-heating method does not have obvious temperature gradients, and heats more evenly, which is conducive to improving the density of the product.

[0036] The embodiment of the present invention provides a method for preparing a powder high speed steel billet, comprising the following steps:

[0037] S1. Raw material powder filling

[0038] The raw material powder is filled into the mold, and the filling volume accounts for 50%-80% of the total volume of the mold. The material of the mold is not limited, for example, it can be a common high temperature resistant material, specifically graphite.

[0039] In some embodiments, in terms of mass percentage, the raw material powder has a chromium content of 20%-22%, a molybdenum content of 1.0%-2.0%, a cobalt content of 1.0%-1.5%, a vanadium content of 0.6%-1.0%, a carbon content of 1.9%-2.2%, and the remainder is iron. The raw material powders with the contents of each component within the above range are suitable for the sintering method provided by the embodiment of the present invention, and the density and other properties of the prepared powder high-speed steel billet meet the process requirements. The raw material powder can be spherical or quasi-spherical, with a sphericity greater than 0.8.

[0040] Specifically, measured by mass percentage, the chromium content in the raw material powder can be 20.0%, 20.5%, 21.0%, 21.5%, 22.0% or the like; the molybdenum content can be 1.0%, 1.5%, 2.0% or the like; the cobalt content can be 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5% or the like; the vanadium content can be 0.6%, 0.7%, 0.8%, 0.9%, 1.0% or the like; the carbon content can be 1.9%, 2.0%, 2.1%, 2.2% or the like.

[0041] In some embodiments, Figure 2 As shown, the raw material powder is divided into fine powder, medium powder and coarse powder according to the particle size range. The particle size range of fine powder is 2μm-66μm, the particle size range of medium powder is 5μm-209μm, and the particle size range of coarse powder is 71μm-400μm; preferably, the raw material powder is medium powder. The maximum value of the loose density and tap density of the powder is achieved through particle size grading. Specifically, the particle size refers to the average particle size Dv50.

[0042] S2, high frequency induction hot pressing sintering

[0043] The mold filled with raw material powder is placed in a high-frequency induction hot pressing sintering furnace, followed by the pre-pressing stage, the heating and pressure increasing stage, the heat preservation and pressure maintaining stage, and the cooling and pressure reducing stage. The high-frequency induction hot pressing sintering furnace is used for sintering. By regulating the sintering process, the performance of the powder high-speed steel billet obtained after sintering is more excellent, reaching or even exceeding the performance of products prepared by conventional hot isostatic pressing methods. The specific model of the high-frequency induction hot pressing sintering furnace is not limited, such as Guangneng Equipment-HPS-200, etc.

[0044] In some embodiments, during the pre-pressing stage, the pressure is controlled to be 2MPa-30MPa, and the processing time is 5min-30min. The pre-pressing makes the powder particles closely contact and densely arranged. Specifically, during the pre-pressing stage, the temperature is not regulated, and the pressure inside the mold can be controlled to be 2MPa, 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, etc.

[0045] In some embodiments, during the temperature and pressure rising stage, the temperature is controlled to rise to 1000°C-1250°C, and the pressure is raised to 2MPa-50MPa; preferably, the temperature is controlled to rise to 1000°C-1100°C, and the pressure is raised to 30MPa-50MPa. By regulating the final temperature and pressure of the temperature and pressure rising stage, the temperature and pressure of the heat preservation and pressure holding stage are further controlled, so that the sintering temperature and pressure are more suitable for the sintering of the raw material powder, so that the density and comprehensive performance of the sintered powder high-speed steel billet meet the process requirements.

[0046] Specifically, in the temperature and pressure increasing stages, the final temperature after controlled temperature increase can be 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, etc.; the final pressure after controlled pressure increase can be 2MPa, 5MPa, 10MPa, 15MPa, 20MPa, 25MPa, 30MPa, 35MPa, 40MPa, 45MPa, 50MPa, etc.

[0047] Furthermore, during the temperature and pressure increase stage, the temperature increase rate is controlled to be 10°C / min-100°C / min, and the pressure increase rate is controlled to be 0.5MPa / min-20MPa / min; preferably, the temperature increase rate is controlled to be 80°C / min-100°C / min, and the pressure increase rate is controlled to be 0.5MPa / min-5MPa / min. By regulating the temperature and pressure increase rates, it is possible to prevent the temperature increase or pressure increase rate from affecting product performance too quickly, and the temperature increase or pressure increase rate from prolonging the production cycle too slowly.

[0048] Specifically, in the temperature and pressure rising stages, the temperature rising rate can be controlled to be 10℃ / min, 20℃ / min, 30℃ / min, 40℃ / min, 50℃ / min, 60℃ / min, 70℃ / min, 80℃ / min, 90℃ / min, 100℃ / min, etc.; the pressure rising rate can be 0.5MPa / min, 1.0MPa / min, 3.0MPa / min, 5.0MPa / min, 8.0MPa / min, 10.0MPa / min, 15.0MPa / min, 20.0MPa / min, etc.

[0049] In some embodiments, during the heat preservation and pressure holding stage, the heat preservation and pressure holding time is controlled to be 10 min-120 min, preferably 10 min-60 min, such as 10 min, 30 min, 50 min, 60 min, 80 min, 100 min, 120 min, etc. It is preferable that the heat preservation and pressure holding time is controlled within the above range so that the prepared powder high speed steel billet can achieve better density.

[0050] In some embodiments, the cooling rate is controlled to be 5°C / min-100°C / min, and the pressure reduction rate is 0.5MPa / min-20MPa / min during the cooling and pressure reduction stage; preferably, the cooling rate is controlled to be 80°C / min-100°C / min, and the pressure reduction rate is 0.5MPa / min-5MPa / min during the cooling and pressure reduction stage. It is advisable to control the cooling and pressure reduction rates within the above range to prevent the temperature or pressure from decreasing too quickly and affecting the product performance.

[0051] Specifically, in the temperature reduction and pressure reduction stage, the temperature reduction rate can be controlled to be 5℃ / min, 10℃ / min, 20℃ / min, 30℃ / min, 40℃ / min, 50℃ / min, 60℃ / min, 70℃ / min, 80℃ / min, 90℃ / min, 100℃ / min, etc.; the pressure reduction rate can be 0.5MPa / min, 1.0MPa / min, 3.0MPa / min, 5.0MPa / min, 8.0MPa / min, 10.0MPa / min, 15.0MPa / min, 20.0MPa / min, etc.

[0052] S3, demoulding

[0053] After the pressure is completely unloaded and the temperature drops to 15°C-30°C (such as room temperature), the powder high-speed steel blank is demolded and the mechanical properties of the obtained powder high-speed steel are tested.

[0054] An embodiment of the present invention also provides a powder high-speed steel billet, which is prepared by the method provided by the embodiment of the present invention. The powder high-speed steel prepared by the present invention can reach a density of 98.5%, a microhardness of 365Hv, and a tensile strength and a yield strength of 723MPa and 687MPa respectively. The obtained powder high-entropy steel billet can be used to manufacture hardware knives and scissors, mechanical molds, etc.

[0055] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0056] Example 1

[0057] This embodiment provides a method for preparing a powder high speed steel billet, and the specific steps are as follows:

[0058] (1) Use medium-sized powder (particle size distribution 5 to 209 μm, see Figure 2 ), filled into graphite mold.

[0059] Calculated by mass percentage, the raw material powder contains 21% chromium, 1.5% molybdenum, 1.2% cobalt, 0.8% vanadium, 2.0% carbon, and the remainder is iron.

[0060] (2) Place the mold in a high-frequency induction hot pressing sintering furnace and evacuate to 1x10 -1 pa, preset pressure 30MPa, processing time 30min.

[0061] (3) The temperature was increased to 1050°C and the pressure was increased to 50 MPa at a heating rate of 100°C / min and a pressure rate of 5 MPa / min.

[0062] (4) Maintain the temperature and pressure for 10 minutes under the temperature and pressure conditions after the temperature and pressure increase in step (3).

[0063] (5) Control the cooling rate to 100°C / min and the pressure reduction rate to 5 MPa / min. After cooling (to room temperature, about 25°C) and releasing the pressure, demold and take out.

[0064] Performance testing: Characterize the sample structure obtained by sintering and test its mechanical properties.

[0065] The results show that the sample density is 98.5%, the microhardness is 365Hv, and the tensile strength and yield strength are 723MPa and 687MPa respectively.

[0066] Figure 3 This is a scanning electron microscope photograph of the powder high-speed steel billet prepared in Example 1. It can be seen that the surface density of the steel billet is very high, there are very few pores, and the pore size is small.

[0067] Figure 4 The microscopic precipitation phase structure of the powder high speed steel prepared in Example 1 shows that the precipitation particles are distributed along the grain boundaries and are relatively uniform.

[0068] Figure 5 The fracture morphology of the powder high speed steel prepared in Example 1 shows that the fracture has dissociation fracture characteristics and carbide particles can be found.

[0069] Example 2

[0070] This embodiment provides a method for preparing a powder high speed steel billet, and the specific steps are as follows:

[0071] (1) Same as step (1) of Example 1.

[0072] (2) Place the mold in a high-frequency induction hot pressing sintering furnace and evacuate to 1x10 -1 pa, preset pressure 30MPa, processing time 30min.

[0073] (3) The temperature was increased to 1050°C and the pressure was increased to 50 MPa at a heating rate of 100°C / min and a pressure rate of 0.5 MPa / min.

[0074] (4) Maintain the temperature and pressure for 10 minutes under the temperature and pressure conditions after the temperature and pressure increase in step (3).

[0075] (5) Control the cooling rate to 80°C / min and the pressure reduction rate to 0.5 MPa / min. After cooling (to room temperature, about 25°C) and releasing the pressure, demold and take out.

[0076] The results show that the density of the sample in this embodiment is 97.8%, the microhardness is 343Hv, and the tensile strength and yield strength are 709MPa and 675MPa respectively.

[0077] Example 3

[0078] This embodiment provides a method for preparing a powder high speed steel billet, and the specific steps are as follows:

[0079] (1) Same as step (1) of Example 1.

[0080] (2) Place the mold in a high-frequency induction hot pressing sintering furnace and evacuate to 1x10 -1 pa, preset pressure 30MPa, processing time is 5min.

[0081] (3) The temperature was increased to 1050°C and the pressure was increased to 50 MPa at a heating rate of 100°C / min and a pressure rate of 0.5 MPa / min.

[0082] (4) Maintain the temperature and pressure for 10 minutes under the temperature and pressure conditions after the temperature and pressure increase in step (3).

[0083] (5) Control the cooling rate to 100°C / min and the pressure reduction rate to 0.5 MPa / min. After cooling (to room temperature, about 25°C) and releasing the pressure, demold and take out.

[0084] The results show that the density of the sample in this embodiment is 97.1%, the microhardness is 341Hv, and the tensile strength and yield strength are 705MPa and 665MPa respectively.

[0085] Example 4

[0086] The only difference from Example 1 is that in step (3), the temperature is raised to 1000° C. and the pressure is raised to 5 MPa.

[0087] The results show that the sample of this embodiment has a density of 95.3%, a microhardness of 322Hv, and a tensile strength and a yield strength of 653MPa and 598MPa respectively.

[0088] Example 5

[0089] The only difference from Example 1 is that in step (3), the temperature is raised to 1250° C. and the pressure is raised to 50 MPa.

[0090] The results show that the density of the sample in this embodiment is 98.1%, the microhardness is 312Hv, and the tensile strength and yield strength are 643MPa and 582MPa respectively.

[0091] Example 6

[0092] The only difference from Example 1 is that in step (3), the temperature is raised to 1050° C. and the pressure is raised to 30 MPa.

[0093] The results show that the density of the sample in this embodiment is 95.4%, the microhardness is 362Hv, and the tensile strength and yield strength are 702MPa and 651MPa respectively.

[0094] Example 7

[0095] The only difference from Example 1 is that step (4) is to maintain the temperature and pressure for 60 minutes.

[0096] The results show that the density of the sample in this embodiment is 97.8%, the microhardness is 352Hv, and the tensile strength and yield strength are 687MPa and 601MPa respectively.

[0097] Example 8

[0098] The only difference from Example 1 is that step (4) is to maintain the temperature and pressure for 120 minutes.

[0099] The results show that the density of the sample in this embodiment is 97.8%, the microhardness is 356Hv, and the tensile strength and yield strength are 678MPa and 587MPa respectively.

[0100] Example 9

[0101] The only difference from Example 1 is that the preset pressure in step (2) is 2 MPa.

[0102] The results show that the density of the sample in this embodiment is 93.5%, the microhardness is 312Hv, and the tensile strength and yield strength are 565MPa and 499MPa respectively.

[0103] Example 10

[0104] The only difference from Example 1 is that the heating / cooling rate in step (3) and step (5) is 80°C / min.

[0105] The results show that the density of the sample in this embodiment is 98.1%, the microhardness is 340Hv, and the tensile strength and yield strength are 633MPa and 573MPa respectively.

[0106] Comparative Example 1

[0107] This comparative example provides a traditional hot isostatic pressing sintering process, and the specific steps are as follows: putting powder or powder compact into a bag; removing the gas adsorbed on the powder surface, the gaps between powders and the bag; vacuum sealing the bag and placing it in a hot isostatic press, raising the temperature and pressure to 1050°C and 50MPa, and maintaining the temperature and pressure for 2 hours; after removing the sample, removing the bag by mechanical or acid leaching method to obtain a product.

[0108] The results show that the density of the comparative example sample is 98.5%, the microhardness is 356Hv, and the tensile strength and yield strength are 717MPa and 593MPa respectively.

[0109] Comparative Example 2

[0110] The only difference from Example 1 is that step (2) is not performed.

[0111] The results show that the density of the comparative example sample is 87.2%, the microhardness is 345Hv, and the tensile strength and yield strength are 522MPa and 456MPa respectively.

[0112] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a powder high speed steel billet, characterized in that: include: The raw material powder is filled into a mold, and placed in a high-frequency induction hot pressing sintering furnace to sequentially undergo a pre-pressing stage, a temperature and pressure increasing stage, a temperature and pressure maintaining stage, and a temperature and pressure reducing stage.

2. The method according to claim 1, characterized in that In the temperature and pressure increasing stage, the temperature is controlled to be increased to 1000° C.-1250° C., and the pressure is increased to 2 MPa-50 MPa; Preferably, during the temperature and pressure increasing stage, the temperature is controlled to be increased to 1000° C.-1100° C., and the pressure is increased to 30 MPa-50 MPa.

3. The method according to claim 2, characterized in that In the temperature and pressure increasing stage, the temperature increasing rate is controlled to be 10°C / min-100°C / min, and the pressure increasing rate is controlled to be 0.5MPa / min-20MPa / min; Preferably, during the temperature and pressure increase stage, the temperature increase rate is controlled to be 80°C / min-100°C / min, and the pressure increase rate is controlled to be 0.5MPa / min-5MPa / min.

4. The method according to claim 1, characterized in that: During the heat preservation and pressure maintenance stage, the heat preservation and pressure maintenance time is controlled to be 10 minutes to 120 minutes, preferably 10 minutes to 60 minutes.

5. The method according to claim 1, characterized in that: The temperature reduction and pressure reduction stage controls the temperature reduction rate to be 5°C / min-100°C / min, and the pressure reduction rate to be 0.5MPa / min-20MPa / min; Preferably, the temperature reduction rate in the temperature reduction and pressure reduction stage is controlled to be 80°C / min-100°C / min, and the pressure reduction rate is controlled to be 0.5MPa / min-5MPa / min; Preferably, demoulding is performed after the pressure is completely unloaded and the temperature drops to 15°C-30°C.

6. The method according to claim 1, characterized in that In the pre-pressing stage, the pressure is controlled to be 2MPa-30MPa, and the processing time is 5min-30min.

7. The method according to claim 1, characterized in that In terms of mass percentage, the raw material powder has a chromium content of 20%-22%, a molybdenum content of 1.0%-2.0%, a cobalt content of 1.0%-1.5%, a vanadium content of 0.6%-1.0%, a carbon content of 1.9%-2.2%, and the remainder is iron; Preferably, the raw material powder has a sphericity greater than 0.

8.

8. The method according to claim 7, characterized in that The raw material powder is divided into fine powder, medium powder and coarse powder according to the particle size range, the particle size range of the fine powder is 2μm-66μm, the particle size range of the medium powder is 5μm-209μm, and the particle size range of the coarse powder is 71μm-400μm; Preferably, the raw material powder is medium powder.

9. A powder high speed steel billet, characterized in that: Prepared by the method according to any one of claims 1 to 8.

10. Use of the powder high-speed steel billet according to claim 9 in the preparation of hardware knives and scissors or mechanical molds.

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