Cr-containing pre-alloy base powder, CrMoNi pre-alloy powder metallurgy PM material and preparation method thereof

Abstract

The invention relates to the technical field of powder metallurgy, in particular to Cr-containing pre-alloy base powder, a CrMoNi pre-alloy powder metallurgy PM material and a preparation method thereof. The Cr-containing pre-alloyed base powder is composed of the following chemical components in percentage by mass: 2.8%-3.3% of Cr, 0.90%-1.2% of Si and the balance of iron, and the sum of the mass percentages of all the chemical components is 100%. The Cr-containing pre-alloyed base powder is mixed with pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, a flow aid and a binder, and the CrMoNi pre-alloyed powder metallurgy PM material is obtained through pressing, sintering and tempering treatment. Compared with an existing high-strength Cr-containing pre-alloy powder metallurgy material, the CrMoNi pre-alloy powder metallurgy PM material has higher tensile strength, and the requirements of the market for the high-strength and high-performance Cr-containing pre-alloy powder metallurgy material are met.

Description

Technical Field

[0001] The invention relates to the technical field of powder metallurgy, and in particular to Cr-containing pre-alloyed base powder, CrMoNi pre-alloyed powder metallurgy PM material and a preparation method thereof. Background Art

[0002] As an advanced process integrating material preparation and forming, powder metallurgy has played an important role in modern industry with its advantages of high efficiency, energy saving and high material utilization rate. In particular, the application of powder metallurgy materials is becoming more and more extensive in the high-tech fields of automobiles, aerospace, weapons manufacturing and electronic information.

[0003] Cr-containing pre-alloyed powder metallurgy materials, due to their good corrosion resistance, high temperature strength and wear resistance, show unique performance advantages in specific industrial environments, and have become indispensable key materials in many fields. However, the high-strength Cr-containing pre-alloyed powder metallurgy materials on the market are mainly imported, and their prices are relatively high, which limits their application scope. At the same time, the tensile strength of high-strength Cr-containing pre-alloyed powder metallurgy materials on the market is mainly concentrated in the range of 700Mpa~850Mpa, which cannot meet the application requirements under some extreme conditions. Therefore, the development of Cr-containing pre-alloyed powder metallurgy materials with higher strength and better performance and their preparation methods are of great strategic significance and market demand. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a Cr-containing pre-alloyed base powder, a CrMoNi pre-alloyed powder metallurgy PM material and a preparation method thereof. The present invention provides a Cr-containing pre-alloyed base powder, which optimizes the performance of the Cr-containing pre-alloyed base powder by precisely controlling the Cr element content to 2.8% to 3.3% and the Si element content to 0.90% to 1.2%. Furthermore, the Cr-containing pre-alloyed base powder of the present invention is mixed with pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, a flow aid and a binder, and the CrMoNi pre-alloyed powder metallurgy PM material is obtained by pressing, sintering and tempering. Compared with the high-strength Cr-containing pre-alloyed powder metallurgy materials on the existing market, the CrMoNi pre-alloyed powder metallurgy PM material of the present invention has higher tensile strength, meeting the market demand for high-strength and high-performance Cr-containing pre-alloyed powder metallurgy materials.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: The first object of the present invention is to provide a Cr-containing pre-alloyed base powder, which is composed of the following chemical components in mass percentage: Cr 2.8%~3.3% and Si 0.90%~1.2%, the balance is iron, and the sum of the mass percentages of each chemical component is 100%.

[0006] Preferably, the particle size of the Cr-containing pre-alloyed base powder is 63 μm to 180 μm; wherein, the particle size distribution of the Cr-containing pre-alloyed base powder affects its bulk density, that is, the density of the Cr-containing pre-alloyed base powder when naturally stacked without external force; the finer the particle size, the smaller the bulk density; and by adjusting the particle size distribution, the bulk density can be optimized, thereby affecting the overall density and mechanical properties of the powder metallurgy product. In addition, the Cr-containing pre-alloyed base powder with uniform particle size distribution is easier to achieve uniform densification during the sintering process, which helps to improve the density and strength of the final metallurgical product. On the contrary, if the particle size distribution is uneven, it will lead to uneven sintering, defects, and reduced material properties.

[0007] The second object of the present invention is to provide a method for preparing the above-mentioned Cr-containing pre-alloyed base powder, comprising the following steps: S1. Weigh industrial pure iron, metallic chromium and ferrosilicon powder according to the mass percentage of the chemical composition of the Cr-containing pre-alloyed base powder.

[0008] S2. Mix industrial pure iron, metallic chromium and ferrosilicon powder, and smelt them to obtain molten steel.

[0009] S3, atomizing the molten steel to obtain Cr-containing pre-alloyed base powder.

[0010] Preferably, the oxygen blowing pressure during the smelting process is 0.6 MPa to 0.8 MPa.

[0011] Preferably, the tapping temperature is 1690°C to 1740°C.

[0012] Preferably, the temperature of the atomization treatment is 1650° C. to 1710° C., the pressure is 11 MPa to 12 MPa, and the vacuum degree is -0.06 MPa to 0.02 MPa.

[0013] Among them, as far as the atomization temperature is concerned, if the atomization temperature is higher or lower than this range, the atomization process will fail, and the particle size of the Cr-containing pre-alloyed base powder will be too coarse or too fine; as far as the pressure is concerned, if the pressure is higher or lower than this range, it will easily cause the composition of the Cr-containing pre-alloyed base powder to exceed the allowable deviation range, affecting the quality and performance of the final Cr-containing pre-alloyed base powder; as far as the vacuum degree is concerned, if the vacuum degree exceeds the prescribed range, the hydrogen loss of the Cr-containing pre-alloyed base powder will be significantly increased, and the purity and use effect of the Cr-containing pre-alloyed base powder will be adversely affected.

[0014] The third object of the present invention is to provide a CrMoNi pre-alloyed powder metallurgy PM material, which is prepared by the above-mentioned Cr-containing pre-alloyed base powder, and the CrMoNi pre-alloyed powder metallurgy PM material is composed of the following chemical components in mass percentage: Cr 1.0%~1.5%, Mo 0.60%~1.0%, Ni 2.0%~2.6%, Cu 1.6%~2.2%, C 0.8%~1.3%, zinc stearate 0.6%~0.8%, flow aid 0.5%, binder 0.03%, the remainder is iron and impurities, and the sum of the mass percentages of each chemical component is 100%.

[0015] A fourth object of the present invention is to provide a method for preparing the above-mentioned CrMoNi pre-alloyed powder metallurgy PM material, comprising the following steps: S1. According to the mass percentage of the chemical composition of the CrMoNi pre-alloyed powder metallurgy PM material, weigh the Cr pre-alloyed base powder, pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, flow aid and binder.

[0016] S2. Mixing Cr-containing pre-alloyed base powder, pre-alloyed molybdenum-containing base powder, nickel powder, copper powder, graphite, zinc stearate, a flow aid and a binder to obtain CrMoNi pre-alloyed powder.

[0017] S3. Pressing the CrMoNi pre-alloyed powder into a test bar to obtain a pressed test bar.

[0018] S4. Place the pressed test rod horizontally on a ceramic plate and perform sintering treatment to obtain a sintered sample rod.

[0019] S5. Place the sintered sample rod horizontally on a ceramic plate for tempering to obtain a CrMoNi pre-alloyed powder metallurgy PM material.

[0020] Preferably, the bulk density of the CrMoNi pre-alloyed powder is 3.0 g / cm 3 ~3.3g / cm 3 , fluidity 28s / 50g~36s / 50g.

[0021] Preferably, the sintering treatment conditions are: sintering for 2.0h~2.5h at 1135°C~1145°C, a mesh speed of 110mm / min~130mm / min, and a fan of 12Hz~23Hz.

[0022] Preferably, the tempering treatment conditions are: mesh-belt tempering treatment for 1.5 h to 2 h at 190° C. to 200° C. and a mesh speed of 110 mm / min to 130 mm / min.

[0023] Preferably, the thickness of the two ends and the middle part of the pressed test bar is 6.3 mm ± 0.05 mm, and the density of the pressed test bar is ≥ 7.05 g / cm 3 , and there should be no cracks on the appearance of the pressed test bar.

[0024] Preferably, in the pre-alloyed molybdenum-based powder, the mass percentage of molybdenum is 1.5%, and the balance is iron.

[0025] Preferably, the pre-alloyed molybdenum-based powder is prepared according to the following steps: Industrial pure iron and metallic molybdenum are mixed, smelted under an oxygen blowing pressure of 0.6MPa, and tapped at 1690°C to obtain molten steel; wherein the mass percentage of metallic molybdenum is 1.5%, the remainder is industrial pure iron, and the sum of the mass percentages of industrial pure iron and metallic molybdenum is 100%; the molten steel is sent to an atomizing device, atomized under conditions of a temperature of 1650°C, an atomizing pressure of 11MPa and a vacuum degree of -0.06MPa, dried at 100°C, and crushed and screened to obtain pre-alloyed molybdenum-based powder.

[0026] Preferably, the binder is selected from the flow agent R330.

[0027] Preferably, the flow aid is selected from the powder metallurgy binder DCS-200 BAP-1.

[0028] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a Cr-containing pre-alloyed base powder, which is composed of the following chemical components in mass percentage: Cr 2.8%~3.3% and Si 0.90%~1.2%, and the rest is iron, and the sum of the mass percentages of each chemical component is 100%. The particle size distribution of the Cr-containing pre-alloyed base powder is relatively uniform, wherein particles below -45μm account for 58.28%, indicating that fine particles account for a large proportion in the Cr-containing pre-alloyed base powder, which is beneficial to subsequent processing and application.

[0029] 2. Compared with the high-strength Cr-containing pre-alloyed powder metallurgy materials on the current market, the tensile strength is generally 700MPa to 850MPa. The Cr-containing pre-alloyed base powder of the present invention is mixed with pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, flow aid and binder, and the CrMoNi pre-alloyed powder metallurgy PM material prepared by pressing, sintering and tempering shows significantly enhanced performance characteristics, and its tensile strength is as high as 950MPa to 1100MPa, achieving a leap in performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the stress-strain curve of the CrMoNi pre-alloyed powder metallurgy PM material of Example 1.

[0031] Figure 2 This is the stress-strain curve of the CrMoNi pre-alloyed powder metallurgy PM material of Example 2.

[0032] Figure 3 This is the stress-strain curve of the CrMoNi pre-alloyed powder metallurgy PM material of Example 3.

[0033] Figure 4 This is the stress-strain curve of the high-strength Cr-containing pre-alloyed powder metallurgy material with a grade of 4300 on the market. DETAILED DESCRIPTION

[0034] The technical solution of the present invention will be clearly and completely described below in combination with the data in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods. Among them, the ferrosilicon powder of the present invention is selected from FeSi75-A, and the mass percentage of silicon is 74.5% to 80%; the powder metallurgy flow aid R330, abbreviated as R330, is purchased from Shanghai Nazhong Chemical New Materials Co., Ltd.; the powder metallurgy binder DCS-200 BAP-1, abbreviated as DCS-200BAP-1, is purchased from Nanjing Tianshi Lubricant Co., Ltd.

[0036] In the prior art, although the powder metallurgy process has been widely used in many high-tech fields due to its unique advantages in material preparation and forming, and Cr-containing pre-alloyed powder metallurgy materials are also favored due to their excellent corrosion resistance, high temperature strength and wear resistance, the technology still faces many challenges. However, the supply of high-strength Cr-containing pre-alloyed powder metallurgy materials on the market mainly relies on imports, and the high price limits its application scope. In addition, although the tensile strength range of existing high-strength Cr-containing pre-alloyed powder metallurgy materials can meet general needs, their performance is still insufficient under certain extreme conditions, such as ultra-high pressure, ultra-high temperature or strong corrosive environment.

[0037] In view of the problems existing in the above-mentioned prior art, the present invention provides a Cr-containing pre-alloyed base powder composed of the following chemical components in mass percentage: Cr 2.8%~3.3%, Si 0.90%~1.2%, and the balance is iron, and the sum of the mass percentages of the chemical components is 100%.

[0038] The present invention takes into account the introduction of low-cost Cr elements into powder metallurgy materials, aiming to form a fine and evenly dispersed Cr-containing pre-alloyed base powder by adding Cr. This characteristic significantly enhances the hardness and wear resistance of the Cr-containing pre-alloyed base powder. In addition, the Cr element can also naturally form a dense oxide protective film on the surface of the Cr-containing pre-alloyed base powder, which effectively blocks the erosion of corrosive media, thereby greatly improving the corrosion resistance of the Cr-containing pre-alloyed base powder. Therefore, the Cr-containing pre-alloyed base powder of the present invention can be used to manufacture parts that operate in extreme corrosive environments, including but not limited to key components of chemical equipment and important parts in marine engineering equipment, showing a wide range of application potential and value.

[0039] The Cr-containing pre-alloyed base powder of the present invention is mixed with pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, flow aid and binder, and the obtained CrMoNi pre-alloyed powder metallurgy PM material has high tensile strength and toughness, and can meet the use requirements under complex working conditions. The CrMoNi pre-alloyed powder metallurgy PM material of the present invention can not only be used in automobile DCT transmission powder metallurgy synchronizers, engine parts, and high-strength special-shaped structural parts, but also can effectively withstand higher loads and stress levels, thereby significantly improving the gear shifting smoothness of the transmission and the reliability and durability of the engine.

[0040] Example 1 A method for preparing a CrMoNi pre-alloyed powder metallurgy PM material comprises the following steps: S1. Preparation of Cr-containing pre-alloyed base powder: First, 96kg of industrial pure iron, 3kg of metallic chromium and 1kg of ferrosilicon powder were mixed, and smelted at a temperature of 1690℃ and an oxygen blowing pressure of 0.6MPa to obtain molten steel; then, the molten steel was sent to an atomizing device, and atomized at a temperature of 1650℃, an atomizing pressure of 11MPa and a vacuum degree of -0.06MPa, and dried at 100℃. After crushing and screening, Cr-containing pre-alloyed base powder was obtained. Among them, the chemical composition of the Cr-containing pre-alloyed base powder is: 0.9% silicon, 3.3% chromium, and 95.8% iron.

[0041] Preparation of S2, CrMoNi pre-alloyed powder metallurgy PM materials: Firstly, Cr pre-alloyed base powder, pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, R330 and DCS-200 BAP-1 were mixed in a mass ratio of 43:52.04:2:2:0.55:0.35:0.03:0.03 to obtain CrMoNi pre-alloyed powder; then, the CrMoNi pre-alloyed powder was prepared at a density of 7.05 g / cm3 The test rod is pressed to obtain a pressed test rod; wherein, the middle thickness of the pressed test rod is 6.3 mm, and the thickness of both ends is 6.3 mm; then, the pressed test rod is placed flat on a ceramic flat plate, and placed in a German mesh belt rapid cooling sintering furnace for rapid cooling sintering, and the sintering temperature is set to 1135°C, the mesh speed is 110 mm / min, and the fan is 23 Hz to obtain a sintered sample rod; finally, the sintered sample rod is tempered at 200°C for 1.5 hours, and then naturally cooled to room temperature to obtain a CrMoNi pre-alloyed powder metallurgy PM material.

[0042] The obtained CrMoNi pre-alloyed powder metallurgy PM material contains 1.5wt% Cr, 1.0wt% Mo, 2.6wt% Ni, 2.2wt% Cu and 1.3wt% C.

[0043] Example 2 A method for preparing a CrMoNi pre-alloyed powder metallurgy PM material comprises the following steps: S1. Preparation of Cr-containing pre-alloyed base powder: First, 96kg of industrial pure iron, 3kg of metallic chromium and 1kg of ferrosilicon powder were mixed, and smelted at a temperature of 1740°C and an oxygen blowing pressure of 0.8MPa to obtain molten steel; then, the molten steel was sent to an atomizing device, and atomized at a temperature of 1710°C, an atomizing pressure of 12MPa and a vacuum degree of 0.02MPa, and dried at 100°C, and after crushing and screening, a Cr-containing pre-alloyed base powder was obtained. Among them, the chemical composition of the Cr-containing pre-alloyed base powder is: 1.2% silicon, 3% chromium, and 95.8% iron.

[0044] Preparation of S2, CrMoNi pre-alloyed powder metallurgy PM materials: Firstly, Cr pre-alloyed base powder, pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, R330 and DCS-200 BAP-1 were mixed in a mass ratio of 43:52.04:2:2:0.55:0.35:0.03:0.03 to obtain CrMoNi pre-alloyed powder; then, the CrMoNi pre-alloyed powder was prepared at a density of 7.05 g / cm 3 The test rod is pressed to obtain a pressed test rod; wherein, the middle thickness of the pressed test rod is 6.25 mm, and the thickness of both ends is 6.25 mm; then, the pressed test rod is placed flat on a ceramic flat plate, and placed in a German mesh belt rapid cooling sintering furnace for rapid cooling sintering, and the sintering temperature is set to 1135°C, the mesh speed is 110 mm / min, and the fan is 23 Hz to obtain a sintered sample rod; finally, the sintered sample rod is tempered at 200°C for 1.5 hours, and then naturally cooled to room temperature to obtain a CrMoNi pre-alloyed powder metallurgy PM material.

[0045] The obtained CrMoNi pre-alloyed powder metallurgy PM material contains 1.2wt% Cr, 0.8wt% Mo, 2.3wt% Ni, 2.0wt% Cu and 1wt% C.

[0046] Example 3 A method for preparing a CrMoNi pre-alloyed powder metallurgy PM material comprises the following steps: S1. Preparation of Cr-containing pre-alloyed base powder: First, 96kg of industrial pure iron, 3kg of metallic chromium and 1kg of ferrosilicon powder were mixed, and smelted at a temperature of 1740°C and an oxygen blowing pressure of 0.8MPa to obtain molten steel; then, the molten steel was sent to an atomizing device, and atomized at a temperature of 1710°C, an atomizing pressure of 12MPa and a vacuum degree of 0.02MPa, and dried at 100°C, and after crushing and screening, a Cr-containing pre-alloyed base powder was obtained. The chemical composition of the Cr-containing pre-alloyed base powder is: 1% silicon, 2.8% chromium, and 96.2% iron.

[0047] Preparation of S2, CrMoNi pre-alloyed powder metallurgy PM materials: Firstly, Cr pre-alloyed base powder, pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, R330 and DCS-200 BAP-1 were mixed in a mass ratio of 43:52.04:2:2:0.55:0.35:0.03:0.03 to obtain CrMoNi pre-alloyed powder; then, the CrMoNi pre-alloyed powder was prepared at a density of 7.05 g / cm 3 The test rod is pressed to obtain a pressed test rod; wherein, the middle thickness of the pressed test rod is 6.35 mm, and the thickness of both ends is 6.35 mm; then, the pressed test rod is placed flat on a ceramic flat plate, placed in a German rapid cooling sintering furnace for rapid cooling sintering, and the sintering temperature is set to 1135°C, the mesh speed is 130 mm / min, and the fan is 23 Hz to obtain a sintered sample rod; finally, the sintered sample rod is tempered at 200°C for 1.5 hours, and then naturally cooled to room temperature to obtain a CrMoNi pre-alloyed powder metallurgy PM material.

[0048] The obtained CrMoNi pre-alloyed powder metallurgy PM material contains 1.0wt% Cr, 0.6wt% Mo, 2.0wt% Ni, 1.6wt% Cu and 0.8wt% C.

[0049] The Cr-containing pre-alloyed base powder obtained in Example 1 was subjected to physical property, sieve analysis, and chemical property analysis. The results are shown in Tables 1 and 2: Table 1 Physical properties of Cr-containing pre-alloyed base powder prepared in Example 1 Table 2 Analysis results of sieving the Cr-containing pre-alloyed base powder obtained in Example 1 Combining Table 1 and Table 2, it can be concluded that the Cr-containing pre-alloyed base powder prepared in Example 1 of the present invention has good physical properties, with a fluidity of 30.0S / 50g and a bulk density of 2.97g / cm 3 The compact density is as high as 6.68g / cm 3 The sieve analysis results show that the particle size distribution of the Cr-containing pre-alloyed base powder is relatively uniform, of which particles below -45μm account for 58.28%, indicating that fine particles account for a large proportion in the Cr-containing pre-alloyed base powder, which is conducive to subsequent processing and application.

[0050] Taking the CrMoNi pre-alloyed powder metallurgy PM material prepared in Example 1 as an example, its mechanical properties were studied, and the results are shown in Table 3: Table 3 Performance analysis results of CrMoNi pre-alloyed powder obtained in Example 1 It can be concluded from Table 3 that the CrMoNi pre-alloyed powder metallurgy PM material prepared in Example 1 strictly meets the design requirements in terms of chemical composition. The contents of graphite, sulfur, phosphorus, manganese, silicon, and oxygen impurity elements are all controlled at a low level, while the contents of key alloying elements Cr, Mo, and Cu are precisely controlled within a predetermined range, ensuring the excellent performance of the CrMoNi pre-alloyed powder metallurgy PM material. In terms of physical properties, the CrMoNi pre-alloyed powder exhibits good fluidity and loose density, which is conducive to the pressing and molding of the CrMoNi pre-alloyed powder. In addition, its compressibility reaches 7.10 g / cm under a pressure of 600 MPa. 3 , indicating that the CrMoNi pre-alloyed powder has good compression molding ability and density. The particle size analysis results show that most of the particles are concentrated between 150 mesh and 63 mesh, and the proportion of fine particles <63 mesh is as high as 37.8%, which is conducive to the uniform distribution and sintering densification of the CrMoNi pre-alloyed powder.

[0051] Table 4 Mechanical properties of CrMoNi pre-alloyed powder metallurgy PM materials and 4300 powder prepared in Example 1 to Example 3 observe Figure 1 , Figure 2 and Figure 3, combined with Table 4, it can be concluded that the CrMoNi pre-alloyed powder metallurgy PM materials prepared in Examples 1 to 3 have slight differences in elongation and tensile strength. Specifically, Example 2 has the highest elongation, and its tensile strength also reaches the highest 1103MPa, showing good comprehensive toughness and strength performance. Compared with the 4300 powder of the prior art, Figure 4 , Examples 1 to 3 of the present invention have significantly improved elongation after fracture and tensile strength, indicating that the mechanical properties of the CrMoNi pre-alloyed powder metallurgy PM material prepared by using the Cr-containing pre-alloyed base powder of the present invention have been significantly improved.

[0052] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiment, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the present invention.

Claims

1. A Cr-containing pre-alloyed base powder, characterized in that: The Cr-containing pre-alloyed base powder is composed of the following chemical components in mass percentage: Cr 2.8%~3.3%, Si 0.90%~1.2%, and the balance is iron, and the sum of the mass percentages of the chemical components is 100%.

2. The Cr-containing pre-alloyed base powder according to claim 1, characterized in that: The particle size of the Cr-containing pre-alloyed base powder is 63μm~180μm.

3. A method for preparing the Cr-containing pre-alloyed base powder according to claim 1, characterized in that: The following steps are involved: According to the mass percentage of the chemical composition of the Cr-containing pre-alloyed base powder, industrial pure iron, metallic chromium and ferrosilicon powder are weighed; Mix industrial pure iron, metallic chromium and ferrosilicon powder, and then smelt and tap to obtain molten steel; The molten steel is atomized, dried and sieved to obtain Cr-containing pre-alloyed base powder.

4. The method for preparing the Cr-containing pre-alloyed base powder according to claim 3, characterized in that: The oxygen blowing pressure for smelting treatment is 0.6MPa~0.8MPa.

5. The method for preparing the Cr-containing pre-alloyed base powder according to claim 3, characterized in that: The steel tapping temperature is 1690℃~1740℃.

6. A CrMoNi pre-alloyed powder metallurgy PM material, characterized in that: The CrMoNi pre-alloyed powder metallurgy PM material is prepared by using the Cr-containing pre-alloyed base powder according to claim 1, and the CrMoNi pre-alloyed powder metallurgy PM material consists of the following chemical components in mass percentage: Cr 1.0%~1.5%, Mo 0.60%~1.0%, Ni 2.0%~2.6%, Cu 1.6%~2.2%, C 0.8%~1.3%, zinc stearate 0.6%~0.8%, flow aid 0.03%, binder 0.03%, the remainder is iron and impurities, and the sum of the mass percentages of each chemical component is 100%.

7. A method for preparing the CrMoNi pre-alloyed powder metallurgy PM material according to claim 6, characterized in that: The following steps are involved: According to the mass percentage of the chemical composition of the CrMoNi pre-alloyed powder metallurgy PM material, Cr pre-alloyed base powder, pre-alloyed molybdenum base powder, nickel powder, copper powder, graphite, zinc stearate, flow aid and binder are weighed; The Cr-containing pre-alloyed base powder, the pre-alloyed molybdenum-containing base powder, the nickel powder, the copper powder, the graphite, the zinc stearate, the flow aid and the binder are mixed to obtain the CrMoNi pre-alloyed powder; The CrMoNi pre-alloyed powder is subjected to test bar pressing to obtain a pressed test bar; The pressed test rod is placed horizontally on a ceramic plate and sintered to obtain a sintered test rod; The sintered sample rod is placed on a ceramic plate for tempering to obtain a CrMoNi pre-alloyed powder metallurgy PM material.

8. The method for preparing the CrMoNi pre-alloyed powder metallurgy PM material according to claim 7, characterized in that: The bulk density of CrMoNi pre-alloyed powder is 3.0g / cm 3 ~3.3g / cm 3 , the fluidity is 28s / 50g~36s / 50g.

9. The method for preparing the CrMoNi pre-alloyed powder metallurgy PM material according to claim 7, characterized in that: The sintering treatment conditions are: sintering for 2h~2.5h at 1135℃~1145℃, mesh speed 110mm / min~130mm / min, and fan 10Hz~23Hz.

10. The method for preparing the CrMoNi pre-alloyed powder metallurgy PM material according to claim 7, characterized in that: The tempering treatment conditions are: mesh belt tempering treatment for 1.5h~2h at 190℃~200℃ and mesh speed of 110mm / min~130mm / min.

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