A method for preparing a wc-co reinforced iron-based composite

Abstract

A preparation method of WC-Co reinforced iron-based composite material, comprising the following steps: obtaining WC-Co particles; uniformly arranging the WC-Co particles into a casting mold; and casting an iron-based composite material in the casting mold, wherein the iron-based composite material comprises Cr and Mn. Irregular large-size WC-Co particles are added to the iron-based composite material, the WC-Co particles produce dispersion strengthening and solid solution strengthening on the surface layer of the composite material, and the hardness and wear resistance of the composite material are improved; thermal stress, phase change stress and micro stress produce a low-high-low stress state at the interface, residual compressive stress makes the WC-Co particles combined with the matrix, inhibits crack propagation, and prevents the WC-Co particles from falling off from the matrix.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of a WC-Co reinforced iron-based composite material. BACKGROUND

[0002] The iron-based composite material has the advantages of low cost, good toughness and ductility, but with the increasing demand for high-performance structural materials, the particle reinforced iron-based composite material emerges as the times require. The reinforcing particles have high specific strength, specific stiffness and specific modulus, but poor toughness and ductility. Adding the reinforcing particles to the iron-based composite material can improve the strength, hardness and wear resistance of the surface of the composite material, and the iron-based composite material provides support for the reinforcing particles and relieves the impact force on the reinforcing particles. A large number of studies have shown that the smaller the size of the reinforcing particles, the better the physical and mechanical properties of the composite material. However, small-size reinforcing particles are often extruded and detached by friction during use, which causes surface wear, and there is also a problem of poor wettability between the reinforcing particles and the matrix. SUMMARY

[0003] To solve the above problems, the application provides a preparation method of a WC-Co reinforced iron-based composite material, which comprises the following steps: obtaining WC-Co particles; uniformly arranging the WC-Co particles in a casting mold; and pouring an iron-based composite material in the casting mold, wherein the iron-based composite material comprises Cr and Mn. In the application, large-size WC-Co particles in irregular shapes are added to the iron-based composite material, the WC-Co particles produce dispersion strengthening and solid solution strengthening on the surface layer of the composite material, and the hardness and wear resistance of the composite material are improved; thermal stress, phase change stress and micro stress produce a low-high-low stress state at the interface, residual compressive stress makes the WC-Co particles combined with the matrix, inhibits crack propagation and prevents the WC-Co particles from being detached from the matrix.

[0004] Preferably, the WC-Co particles comprise 80-92 parts by mass of WC particles and 8-20 parts by mass of Co.

[0005] Preferably, the particle size of the WC particles is 0.5-3 mu m.

[0006] Preferably, the WC-Co particles are prepared in the following manner:

[0007] The WC particles and Co powder are compressed into a WC-Co block by cold pressing;

[0008] The WC-Co block is placed in a pressure container for hot pressing treatment, N2 and / or Ar are used as the pressurizing medium to apply pressure to each direction of the container at high temperature, and the WC-Co block is directly pressurized and sintered to form a shape.

[0009] The sintered WC-Co block is crushed by a crusher, and the WC-Co particles are sieved by a roller sifter according to the particle size to obtain WC-Co particles with a particle size of 2-8 mm.

[0010] Preferably, the operating temperature of the cold pressing method is 15-25℃;

[0011] The operating pressure is 110-120 MPa;

[0012] The operating time is 3 minutes.

[0013] Preferably, the sintering temperature is 1450-1500℃;

[0014] The operating pressure is 180-195 MPa;

[0015] The operating time is 45 minutes.

[0016] Preferably, the WC-Co particles are placed in the casting mold in the following way:

[0017] The WC-Co particles are placed in alcohol and cleaned of surface dirt using an ultrasonic cleaning device, and then the WC-Co particles are dried;

[0018] The WC-Co particles are placed in a uniform single layer on the bottom surface of the foam plastic mold to ensure uniformity of the WC-Co in the iron-based composite material;

[0019] The foam repair paste is used to seal the opening of the foam plastic mold to prevent the WC-Co from falling off the foam plastic mold;

[0020] The pouring opening of the foam plastic mold is set at the middle position of the opening of the foam plastic mold;

[0021] The surface layer of the plastic mold is evenly coated with refractory paint with a thickness of 0.5-2 mm, and is placed in a drying chamber for 36-60 hours at a temperature of 35-40℃;

[0022] The dried foam plastic mold is placed in the casting mold and fixed by negative pressure.

[0023] Preferably, the foam plastic mold is made of polystyrene plastic material and has the shape of a cuboid or a cube, and is matched with the casting mold;

[0024] The foam repair paste is a polystyrene repair paste;

[0025] The refractory paint is a water-based paint and includes the following raw materials by mass fraction:

[0026] Silica sand powder: 35-40 parts;

[0027] Bauxite: 50-55 parts;

[0028] White latex: 1-3 parts;

[0029] Flame retardant: 0.3-1.5 parts;

[0030] Bentonite: 1-3 parts;

[0031] Binder: 4-5 parts.

[0032] The fire-resistant coating of the present application has the following functions: preventing mechanical sand sticking and thermal-chemical sand sticking of castings; improving the rigidity of foam plastic mold and preventing deformation of foam plastic film; and facilitating the removal of hot decomposition gas of the lost foam mold.

[0033] Preferably, the iron-based composite material comprises the following materials:

[0034] 92.9-94.3 parts by mass of iron, 0.3-0.5 parts by mass of carbon, 4.5-5.5 parts by mass of chromium, and 0.9-1.1 parts by mass of Mn.

[0035] Preferably, the iron-based composite material is cast in the following manner:

[0036] The iron-based composite material powder is mixed and placed in a ball mill tank, and then grinding balls are placed in the tank;

[0037] The ball mill tank is sealed and fixed on a planetary ball mill, and the powder is ground for 20-28 hours under the condition that the revolution direction is the same as the rotation direction, and the rotation speed is 300-400 r / min;

[0038] The particle size of each material in the iron-based composite material is not more than 15 μm, and the ratio of the iron-based composite material powder to the grinding balls is 10 / 1;

[0039] The iron-based composite material powder is placed in a crucible and melted to 1600-1650 ℃, the molten iron-based composite material is continuously cast into a mold, and then cooled to room temperature. The higher melting temperature of the present application ensures a larger element diffusion flux at the interface, prevents the precipitation of a large amount of white brittle hard phase, and continuously casts the molten iron-based composite material into a mold, and then cools to room temperature.

[0040] The thermal expansion coefficients of the WC-Co and the iron-based composite material are different in the cooling process, the shrinkage is inconsistent, the relative deformation of the iron-based composite material is greater than that of the WC-Co, and a large thermal stress is generated. The iron-based composite material undergoes phase transition at 1153℃ and 738℃ to generate phase transition stress. During the cooling process, lattice distortion occurs to generate micro stress. The thermal stress, phase transition stress and micro stress make the interface present a low-high-low residual stress state. The residual compressive stress tightly bonds the WC-Co particles and the matrix, inhibits the crack generation at the interface, and prevents the WC-Co particles from falling off from the matrix.

[0041] The application can bring the following beneficial effects:

[0042] 1. The application adds large-size WC-Co particles of irregular shape to the iron-based composite material. The WC-Co particles generate dispersion strengthening and solid solution strengthening on the surface layer of the composite material, improve the hardness and wear resistance of the composite material, and generate a low-high-low stress state at the interface. The residual compressive stress tightly bonds the WC-Co particles and the matrix, inhibits the crack propagation, and prevents the WC-Co particles from falling off from the matrix.

[0043] 2. The refractory coating of the application has the following effects: preventing the castings from generating mechanical sand sticking and thermal-chemical sand sticking; improving the rigidity of the foam plastic mold and preventing the deformation of the foam plastic film; and helping to remove the lost foam mold pattern thermal decomposition gas.

[0044] 3. The higher temperature during melting ensures a larger element diffusion flux at the interface, prevents a large amount of white brittle hard phase from precipitating, and continuously pours the molten iron-based composite material into the mold and then cools to room temperature.

[0045] 4. The thermal expansion coefficients of the WC-Co and the iron-based composite material are different in the cooling process, the shrinkage is inconsistent, the relative deformation of the iron-based composite material is greater than that of the WC-Co, and a large thermal stress is generated. The iron-based composite material undergoes phase transition at 1153℃ and 738℃ to generate phase transition stress. During the cooling process, lattice distortion occurs to generate micro stress. The thermal stress, phase transition stress and micro stress make the interface present a low-high-low residual stress state. The residual compressive stress tightly bonds the WC-Co particles and the matrix, inhibits the crack generation at the interface, and prevents the WC-Co particles from falling off from the matrix. DETAILED DESCRIPTION

[0046] To clearly illustrate the technical features of the present application, the application will be described in detail below through specific embodiments.

[0047] The application is essentially a structure of setting WC-Co protective layer outside the iron-based composite material, and the protective layer needs to be embedded into the iron-based composite material, a preparation method of WC-Co reinforced iron-based composite material, specifically including the following steps:

[0048] S1 obtaining WC-Co particles;

[0049] The WC-Co particles include 80-92 parts by mass of WC particles and 8-20 parts by mass of Co. The particle size of the WC particles is 0.5-3 μm.

[0050] The WC-Co particles are prepared in the following manner:

[0051] WC particles and Co powder are compressed into a WC-Co block by cold pressing method;

[0052] The WC-Co block is placed in a pressure container for hot pressing treatment. At high temperature, N2 and / or Ar are used as pressurizing medium to apply pressure to each direction of the container, so that the WC-Co block is directly pressure sintered and formed.

[0053] The sintered and formed WC-Co block is crushed by a crusher, and the WC-Co particles are sieved according to particle size by a drum sieve machine to obtain WC-Co particles with a particle size of 2-8 mm.

[0054] The operating temperature of the cold pressing method is 15-25℃;

[0055] The operating pressure is 110-120 MPa;

[0056] The operating time is 3 minutes.

[0057] The sintering temperature is 1450-1500℃;

[0058] The operating pressure is 180-195 MPa;

[0059] The operating time is 45 minutes.

[0060] S2 uniformly arranging the WC-Co particles into a casting mold;

[0061] Placing the WC-Co particles in alcohol and cleaning the surface dirt with an ultrasonic cleaning device, and then drying the WC-Co particles;

[0062] Uniformly placing the WC-Co particles in a single layer on the bottom surface of the foam plastic mold to ensure the uniformity of the WC-Co in the iron-based composite material;

[0063] Using foam repair paste to seal the opening of the foam plastic mold to prevent the WC-Co from falling off the foam plastic mold;

[0064] The casting opening of the foam plastic mold is arranged at the middle position of the opening of the foam plastic mold;

[0065] The surface of the plastic mold is evenly coated with the refractory coating with a thickness of 0.5-2mm, and is placed in a drying chamber and dried for 36-60 hours at a temperature of 35-40℃;

[0066] The dried foam plastic mold is placed in a casting mold and fixed by negative pressure.

[0067] The foam plastic mold is made of polystyrene plastic material and has a cuboid or square shape and is arranged in cooperation with the casting mold;

[0068] The foam repair paste is a polystyrene repair paste;

[0069] The refractory coating is a water-based coating and comprises the following raw materials in parts by mass:

[0070] Silica sand powder: 35-40 parts;

[0071] Bauxite: 50-55 parts;

[0072] White latex: 1-3 parts;

[0073] Flame retardant: 0.3-1.5 parts;

[0074] Bentonite: 1-3 parts;

[0075] Binder: 4-5 parts.

[0076] S3 casts the iron-based composite material in the casting mold, and the iron-based composite material comprises Cr and Mn.

[0077] The iron-based composite material comprises the following materials:

[0078] 92.9-94.3 parts by mass of iron, 0.3-0.5 parts by mass of carbon, 4.5-5.5 parts by mass of chromium, and 0.9-1.1 parts by mass of Mn.

[0079] The iron-based composite material is cast in the following manner:

[0080] The iron-based composite material powder is mixed and placed in a ball mill jar, and then grinding balls are placed in the jar;

[0081] The ball mill jar is sealed and fixed on a planetary ball mill, and the powder is ground for 20-28 hours under the condition that the revolution direction and the rotation direction are in the same direction and the rotation speed is 300-400r / min;

[0082] The particle size of each material in the iron-based composite material is not more than 15μm, and the ratio of the iron-based composite material powder to the grinding balls is 10 / 1;

[0083] The iron-based composite material powder is placed in a crucible, melted to 1600-1650℃, the molten iron-based composite material is continuously cast into a mold, and then cooled to room temperature.

[0084] The test is carried out according to the above steps, and the following examples and comparative examples are obtained:

[0085] Example 1:

[0086] S101 obtaining WC-Co particles;

[0087] The WC-Co particles are prepared in the following manner:

[0088] 80 parts by mass of WC particles and 20 parts by mass of Co powder are compressed into a WC-Co block by cold pressing; the particle size of the WC particles is 0.5-3 μm;

[0089] The WC-Co block is placed in a pressure container for hot pressing treatment, and at high temperature, a mixture of N2Ar in a volume ratio of 1:1 is used as a pressurizing medium to apply pressure to each direction of the container, so that the WC-Co block is directly pressure sintered into a shape.

[0090] The sintered WC-Co block is crushed using a crusher, and the WC-Co particles are sieved according to the particle size using a drum sifter to obtain WC-Co particles with a particle size of 2-8 mm.

[0091] The operating temperature of the cold pressing method is 15℃;

[0092] The operating pressure is 110 MPa;

[0093] The operating time is 3 minutes.

[0094] The sintering temperature is 1450℃;

[0095] The operating pressure is 180 MPa;

[0096] The operating time is 45 minutes.

[0097] S102 uniformly arranging the WC-Co particles into a casting mold;

[0098] The WC-Co particles are placed in alcohol and cleaned with an ultrasonic cleaning device to remove surface dirt, and then the WC-Co particles are dried;

[0099] The WC-Co particles are uniformly placed in a single layer on the bottom surface of a foam plastic mold (polystyrene plastic material, in the shape of a rectangular or cubic, cooperatively arranged with the casting mold) to ensure uniformity of the WC-Co in the iron-based composite material;

[0100] The foam plastic mold opening is sealed with foam repair paste (polystyrene repair paste) to prevent WC-Co from falling off the foam plastic mold;

[0101] The pouring opening of the foam plastic mold is arranged at the middle position of the foam plastic mold opening;

[0102] The surface of the plastic model is evenly coated with a refractory coating with a thickness of 0.5 mm, and is placed in a drying chamber for 36 hours;

[0103] The dried foam plastic mold is placed in a casting mold and fixed by negative pressure.

[0104] The refractory coating is a water-based coating with a water-solid ratio of 1:1, and includes the following raw materials in mass fractions:

[0105] Silica sand powder: 35 parts;

[0106] Bauxite: 50 parts;

[0107] White latex: 1 part;

[0108] Flame retardant: 0.3 parts;

[0109] Bentonite: 1 part;

[0110] Binder: 4 parts.

[0111] S103 casts the iron-based composite material in the casting mold:

[0112] The iron-based composite material includes the following materials:

[0113] 92.9 mass fractions of iron, 0.3 mass fractions of carbon, 4.5 mass fractions of chromium, and 0.9 mass fractions of Mn.

[0114] The iron-based composite material is cast in the following manner:

[0115] The iron-based composite material powder (particle size not exceeding 15 μm) is mixed and placed in a ball mill jar, and then the grinding balls are placed (the ratio of iron-based composite material powder to grinding balls is 10 / 1);

[0116] The ball mill jar is sealed and fixed on a planetary ball mill, and the powder is ball milled for 28 hours under the condition that the revolution direction is the same as the rotation direction, and the rotation speed is 300 r / min;

[0117] The iron-based composite material powder is placed in a crucible and melted to 1600℃, and the molten iron-based composite material is continuously cast into the mold, and then cooled to room temperature to obtain No. 1 casting with a WC-Co reinforced layer. The surface strength, wear resistance, etc. of No. 1 casting are detected.

[0118] The following test parameters are obtained: hardness and wear resistance, for hardness, 10 points are tested on the surface of each material respectively: 10 points are tested on the surface of No. 1 casting, each point is tested three times, the load is 500g, the time is 10s, and the average microhardness is 1250HV 0.5 ; and the average microhardness of the original iron-based casting is 570HV 0.5 .

[0119] The wear resistance of the two composite materials under different impact energies is tested by impact abrasive wear experiment:

[0120] The wear resistance of the iron-based casting and the No. 1 casting material is compared by impact abrasive wear experiment, and the relative wear resistance is calculated by G=T1 / T2. The results show that under the impact energy of 1J, 3J and 5J, the wear resistance of No. 1 casting is 3.215, 2.858 and 2.772 times that of iron-based casting respectively.

[0121] In the formula, G represents the relative wear resistance, T1 represents the wear weight of the iron-based casting, and T2 represents the wear weight of No. 1 casting.

[0122] Example 2:

[0123] S201 obtains WC-Co particles;

[0124] The WC-Co particles are prepared in the following manner:

[0125] 92 parts by mass of WC particles and 8 parts by mass of Co powder are compressed into a WC-Co block by cold pressing method; the particle size of the WC particles is 0.5-3μm

[0126] The WC-Co block is placed in a pressure container for hot pressing treatment. At high temperature, N2 is used as the pressurizing medium to apply pressure to each direction of the container, so that the WC-Co block is directly pressurized and sintered into a shape.

[0127] The sintered WC-Co block is broken by a crusher, and the WC-Co particles are sieved according to the particle size by a drum sieve machine to obtain WC-Co particles with a particle size of 2-8mm.

[0128] The operating temperature of the cold pressing method is 25℃;

[0129] The operating pressure is 120MPa;

[0130] The operating time is 3 minutes.

[0131] The sintering temperature is 1500℃;

[0132] The operating pressure is 195MPa;

[0133] The operating time is 45 minutes.

[0134] S202 uniformly arranging the WC-Co particles into the casting mold;

[0135] The WC-Co particles are placed in alcohol and cleaned of surface dirt using an ultrasonic cleaning device, and then the WC-Co particles are dried;

[0136] The WC-Co particles are uniformly placed in a single layer on the bottom surface of a foam plastic mold (polystyrene plastic material, in the shape of a cuboid or a cube, cooperatively arranged with the casting mold) to ensure uniformity of the WC-Co in the iron-based composite material;

[0137] A foam repair paste (polystyrene repair paste) is used to seal the opening of the foam plastic mold to prevent the WC-Co from falling off the foam plastic mold;

[0138] The pouring opening of the foam plastic mold is set at the middle position of the opening of the foam plastic mold;

[0139] The surface of the plastic mold is uniformly coated with a refractory coating with a thickness of 2 mm, and is placed in a drying chamber for drying for 60 hours;

[0140] The dried foam plastic mold is placed in the casting mold and fixed under negative pressure.

[0141] The refractory coating is a water-based coating with a water-solid ratio of 1:1, and includes the following raw materials in mass fractions:

[0142] Silica sand powder: 40 parts;

[0143] Bauxite: 55 parts;

[0144] White latex: 3 parts;

[0145] Flame retardant: 1.5 parts;

[0146] Bentonite: 3 parts;

[0147] Binder: 5 parts.

[0148] S203 pouring the iron-based composite material into the casting mold;

[0149] The iron-based composite material includes the following materials:

[0150] 94.3 mass fractions of iron, 0.5 mass fractions of carbon, 5.5 mass fractions of chromium, and 1.1 mass fractions of Mn.

[0151] The iron-based composite material is poured in the following manner:

[0152] The iron-based composite powder (particle size not more than 15 μm) is mixed and placed in a ball mill tank, and then a ball mill (iron-based composite powder and ball mill ratio is 10 / 1) is placed;

[0153] The ball mill tank is sealed and fixed on a planetary ball mill, and the powder is ball milled for 20 hours under the condition that the revolution direction is the same as the rotation direction and the rotation speed is 400 r / min;

[0154] The iron-based composite powder is placed in a crucible and melted to 1650℃, and the molten iron-based composite material is continuously cast into a mold, and then cooled to room temperature to obtain a No. 2 casting with a WC-Co reinforced layer. The surface strength, wear resistance and the like of the No. 2 casting are detected.

[0155] The following test parameters are obtained: hardness and wear resistance. For hardness, 10 points on the surface of each material are tested respectively: 10 points on the surface of the No. 2 casting are tested, each point is tested three times, the load is 500g, the time is 10s, and the average microhardness is 1208HV 0.5 ; and the average microhardness of the original iron-based casting is 570HV 0.5 .

[0156] The wear resistance is tested by impact abrasive wear experiment of two kinds of composite materials under different impact work:

[0157] The wear resistance of the iron-based casting and the No. 2 casting material is compared by impact abrasive wear experiment, and the relative wear resistance is calculated by G=T1 / T2. The results show that under the impact work of 1J, 3J and 5J, the wear resistance of the No. 1 casting is 3.511, 3.258 and 2.918 times that of the iron-based casting, respectively.

[0158] In the formula, G refers to the relative wear resistance, T1 refers to the wear weight of the iron-based casting, and T2 refers to the wear weight of the No. 2 casting.

[0159] Comparative Example 1

[0160] The surface strength, wear resistance and the like of the No. 3 casting are detected.

[0161] For hardness, 10 points on the surface of each material are tested respectively: 10 points on the surface of the No. 3 casting are tested, each point is tested three times, the load is 500g, the time is 10s, and the average microhardness is 570HV 0.5 .

[0162] It is actually the iron-based casting in Example 1, and G=1.

[0163] Comparative Example 2

[0164] On the basis of Example 1, small WC-Co particles with a particle size of 100-500 μm are added,

[0165] The No. 4 casting was obtained:

[0166] The surface strength, wear resistance, etc. of the No. 4 casting were detected.

[0167] The following test parameters were obtained: hardness and wear resistance, and for the hardness, 10 points on the surface of each material were respectively tested: 10 points on the surface of the No. 4 casting were tested, each point was tested three times, the loading force was 500g, the time was 10s, and the average microhardness was 1010HV 0.5 ; and the average microhardness of the original iron-based casting was 570HV 0.5 .

[0168] The wear resistance was tested by impact abrasive wear experiment of two kinds of composite materials under different impact energies:

[0169] The wear resistance of the iron-based casting and the No. 4 casting was compared by impact abrasive wear experiment, and the relative wear resistance was calculated by G=T1 / T2. The results showed that under the impact energy of 1J, 3J and 5J, the wear resistance of the No. 1 casting was 2.654, 2.591 and 2.557 times that of the iron-based casting, respectively.

[0170] In the formula, G refers to the relative wear resistance, T1 refers to the wear weight of the iron-based casting, and T2 refers to the wear weight of the No. 4 casting.

[0171] The following test parameters were obtained:

[0172] Comparative Example 3

[0173] On the basis of Example 1, the melting temperature was reduced to 1450℃; the No. 5 casting was obtained:

[0174] The surface strength, wear resistance, etc. of the No. 5 casting were detected.

[0175] The following test parameters were obtained: hardness and wear resistance, and for the hardness, 10 points on the surface of each material were respectively tested: 10 points on the surface of the No. 5 casting were tested, each point was tested three times, the loading force was 500g, the time was 10s, and the average microhardness was 1201HV 0.5 ; and the average microhardness of the original iron-based casting was 570HV 0.5 . However, a large amount of large-size brittle hard phase was precipitated around the WC-Co particles, which reduced the bonding strength between the WC-Co particles and the matrix, and was easy to cause brittle fracture, so that the WC-Co particles fell off from the matrix.

[0176] The wear resistance was tested by impact abrasive wear experiment of two kinds of composite materials under different impact energies:

[0177] The wear resistance of the iron-based casting and the No.5 casting material is compared by impact abrasive wear experiment, the relative wear resistance is calculated by G=T1 / T2, and the results show that the wear resistance of the No.5 casting is 1.782, 1.677 and 1.428 times that of the iron-based casting respectively under the impact energy of 1J, 3J and 5J.

[0178] In the formula, G refers to the relative wear resistance, T1 refers to the wear weight of the No.5 casting, and T2 refers to the wear weight of the iron-based casting.

[0179] The above is only an embodiment of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A method of producing a WC-Co reinforced iron-based composite material, characterized by: The method comprises the following steps: obtaining WC-Co particles; arranging the WC-Co particles uniformly into a casting mold; casting an iron-based composite material in the casting mold, the iron-based composite material comprising Cr and Mn; the WC-Co particles comprise 80-92 parts by mass of WC particles and 8-20 parts by mass of Co; the WC-Co particles are prepared in the following manner: compressing the WC particles and Co powder into a WC-Co block by cold pressing; placing the WC-Co block into a pressure container for hot pressing treatment, applying pressure to each direction of the container at high temperature by using N2 and / or Ar as the pressurizing medium, and directly pressure sintering the WC-Co block into a sintered WC-Co block; crushing the sintered WC-Co block by using a crusher and screening the WC-Co particles according to particle size by using a drum screen to obtain WC-Co particles with a particle size of 2-8 mm; the particle size of the WC particles is 0.5-3 μm; the iron-based composite material comprises the following materials: 92.9-94.3 parts by mass of iron, 0.3-0.5 parts by mass of carbon, 4.5-5.5 parts by mass of chromium, and 0.9-1.1 parts by mass of Mn.

2. The method for preparing a WC-Co reinforced iron-based composite material according to claim 1, characterized in that: the operating temperature of the cold pressing method is 15-25℃; the operating pressure is 110-120 MPa; the operating time is 3 minutes.

3. The method for preparing a WC-Co reinforced iron-based composite material according to claim 1, characterized in that: the sintering temperature is 1450-1500℃; the operating pressure is 180-195 MPa; the operating time is 45 minutes.

4. The method for preparing a WC-Co reinforced iron-based composite material according to claim 1, characterized in that: the WC-Co particles are arranged into the casting mold in the following manner: placing the WC-Co particles into alcohol and cleaning the surface dirt by using an ultrasonic cleaning device, and then drying the WC-Co particles; placing the WC-Co particles uniformly in a single layer on the bottom surface of a foam plastic mold to ensure the uniformity of the WC-Co in the iron-based composite material; using a foam repair paste to seal the opening of the foam plastic mold to prevent the WC-Co from falling off the foam plastic mold; arranging the casting opening of the foam plastic mold at the middle position of the opening of the foam plastic mold; uniformly applying a refractory coating on the surface layer of the plastic mold, the thickness being 0.5-2 mm, and placing the plastic mold into a drying chamber for drying for 36-60 hours at a temperature of 35-40℃; placing the dried foam plastic mold into the casting mold and fixing it by negative pressure.

5. The method of claim 4, wherein the WC-Co reinforced iron-based composite is prepared by the following steps of: the foam plastic mold is made of polystyrene plastic material and has a cuboid or square shape, and is arranged in cooperation with the casting mold; ​ the foam repair paste is a polystyrene repair paste; the refractory coating is a water-based coating and comprises the following raw materials in parts by mass: silica sand powder: 35-40 parts; bauxite: 50-55 parts; white latex: 1-3 parts; flame retardant: 0.3-1.5 parts; bentonite: 1-3 parts; binder: 4-5 parts.

6. The method of claim 1, wherein the WC-Co reinforced iron-based composite is prepared by the steps of: the iron-based composite material is cast in the following manner: ​ mixing the iron-based composite material powder, placing it into a ball mill jar, and then placing grinding balls. Seal the ball mill jar, fix on the planetary ball mill, under the condition of the same direction of revolution and rotation, rotation speed is 300-400r / min, ball mill the powder for 20-28 hours; The particle size of each material in the iron-based composite material is not more than 15μm, and the ratio of the iron-based composite material powder and the grinding ball is 10 / 1; Put the iron-based composite material powder into the crucible, melt to 1600-1650℃, continuously cast the molten iron-based composite material into the model, and then cool to room temperature.