Hob cutter ring and preparation method thereof

Abstract

The invention provides a hobbing cutter ring and a preparation method thereof, and relates to the technical field of metal composite centrifugal casting, and the preparation method comprises the following steps: preparing a prefabricated body which is made of a ceramic metal composite material; the multiple prefabricated bodies are placed in a hob ring mold, then first molten metal is poured into the hob ring mold, the outer ring of the hob ring mold is filled with the first molten metal, meanwhile, the first molten metal is infiltrated into the prefabricated bodies, and a part of the prefabricated bodies are wrapped with the first molten metal; and second molten metal is poured into the hobbing cutter ring mold, the inner ring of the hobbing cutter ring mold is filled with the second molten metal, meanwhile, the second molten metal is infiltrated into the prefabricated body and wraps the other part of the prefabricated body, then heat treatment and machining are conducted, and the hobbing cutter ring is obtained. The prefabricated body has the low-expansion characteristic of ceramic, the direct contact area of the two alloys of the inner ring (layer) and the outer ring (layer) can be reduced, the two alloys are connected through the prefabricated body, an expansion gradient is formed among the two alloys, and the problem that the bonding strength is insufficient is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal composite centrifugal casting, and particularly relates to a hob cutter ring and a preparation method thereof. Background Art

[0002] As a high-end complete set of equipment in the engineering machinery field, a shield machine has high technical complexity and high product added value. It is a "major national weapon" for major underground tunnel engineering construction in the country and is widely used in projects such as subways, railways, water conservancy, highways, and urban pipelines. The hob of the shield machine, as a key component directly acting on the rock surface, its performance and durability have an important impact on the efficiency and safety of tunnel construction. The main function of the shield machine hob is to break rock, directly contact the rock surface during tunneling, and bear the thrust and torsion from the cutter head. However, due to the harsh working environment, the hob often exhibits failure forms such as chipping, fracture, and non-uniform wear during operation, and the complex underground environment can also cause corrosion, further exacerbating the tool wear. Among them, the cutter ring, as the core and vulnerable component of the hob, especially the cutting edge part of the cutter ring, often faces challenges such as poor wear resistance, chipping, fracture, and detachment, directly affecting the construction efficiency and cost.

[0003] Currently, in order to improve the service life of the hob cutter ring, the prior art proposes a composite material hob cutter ring, which usually combines a composite reinforcing alloy with the wear-resistant alloy of the cutter ring body. However, due to the different expansion coefficients of the composite reinforcing alloy and the wear-resistant alloy, the shrinkage spaces during cooling are different, resulting in low bonding strength, cracks appearing at the bonding site, accelerating the failure of the cutter ring, and reducing its service life. Summary of the Invention

[0004] Therefore, the present invention provides a hob cutter ring and a preparation method thereof, which can solve the technical problem of low bonding strength between the composite materials of the hob cutter ring in the prior art.

[0005] To solve the above problems, the present invention provides a preparation method of a hob cutter ring, comprising the following steps:

[0006] Step 1) Prepare a preform, the preform is in a "soil" shape, and the material of the preform is a ceramic metal composite material;

[0007] Step 2) Place a plurality of the preforms in a hob cutter ring mold, and then pour a first metal liquid into the hob cutter ring mold, so that the first metal liquid fills the outer ring of the hob cutter ring mold, and at the same time infiltrates into the preforms and wraps a part of the preforms;

[0008] Step 3) Pour the second metal liquid into the hob ring die, so that the second metal liquid fills the inner ring of the hob ring die, meanwhile infiltrates into the preform, and wraps another part of the preform, then perform heat treatment and machining to obtain the hob ring;

[0009] Wherein, the first metal liquid is the metal liquid of high-hardness wear-resistant steel, and the second metal liquid is the metal liquid of high-toughness steel.

[0010] Further, in the step 1), the steps of preparing the preform include:

[0011] Mix the raw materials to obtain ceramic slurry; make the ceramic slurry into ceramic-metal composite powder; mix the ceramic-metal composite powder with a binder, and then perform pressing treatment to obtain the preform;

[0012] Wherein, the raw materials include ceramic powder, metal powder and volatile solvent;

[0013] Preferably, the volatile solvent is acetone or alcohol;

[0014] Preferably, the ceramic slurry is made into ceramic-metal composite powder by centrifugal spray drying treatment;

[0015] Preferably, the pressing treatment is carried out in a tablet press; preferably, the punch of the tablet press is in a "soil" - shaped structure; more preferably, the tablet press is an automatic tablet press.

[0016] Further, in the raw materials: the mass ratio of the ceramic powder to the metal powder is 8:1 to 10:1; and / or

[0017] The ceramic powder is one or more of WC powder, TiC powder, B4C powder, TiN powder; and / or

[0018] The particle size of the ceramic powder is 250 - 500 mesh; and / or

[0019] The addition amount of the volatile solvent is 0.3 - 0.5% of the total mass of the ceramic powder and the metal powder; and / or

[0020] The addition amount of the binder is 10% - 25% of the total mass of the ceramic powder and the metal powder; and / or

[0021] The metal powder is a mixed powder of high-toughness steel powder and high-hardness wear-resistant steel powder; preferably, the mass ratio of high-toughness steel powder to high-hardness wear-resistant steel powder is 1:1 to 1.5:1; preferably, the high-toughness steel powder is one or more of 20 steel, 42CrMo steel powder, 35CrMo steel powder, 4Cr5MoSiV steel powder, and 40CrNiMo steel powder; preferably, the high-hardness wear-resistant steel powder is a steel powder with a hardness of HRC68 or above.

[0022] Furthermore, the thickness of the preform is 5 to 8 mm; the length of the preform is 3 to 5 cm; and the width of the preform is 2 to 5 mm.

[0023] Further, in the step 2):

[0024] The free ends of the vertical columns of the "earth" shape of the plurality of preforms are away from the center of the hob cutter ring mold and face the outer ring of the hob cutter ring mold; and / or

[0025] The plurality of preforms are evenly distributed along the circumference of the hob cutter ring mold; and / or

[0026] Among the plurality of preforms, the interval angle between two adjacent preforms is 10-20°.

[0027] Furthermore, the hardness of the high-hardness wear-resistant steel is above HRC68; and / or

[0028] The carbon content of the high-hardness wear-resistant steel is 3-4.5wt%; and / or

[0029] The alloy content of high hardness wear-resistant steel is 30-40wt%; and / or

[0030] In terms of mass percentage, the composition of high hardness wear-resistant steel is: C: 3~3.5wt%, V: 7~9wt%, Mo: 1.5~3wt%, Si: 1~1.5wt%, Mn: 0.2~0.5wt%, Ni: 1~3wt%, N: 0.1~0.3wt%, W: 2~3wt%, Al: 0.5~0.8wt%, Co: 1~1.5wt%, Nb: 0.5~1wt%, and the balance is Fe.

[0031] Furthermore, in the step 2), the first molten metal is poured into the hob cutter ring mold by vertical centrifugal casting;

[0032] Preferably, the pouring temperature of the first molten metal is 1530-1550°C;

[0033] Preferably, the initial centrifugal speed during vertical centrifugal casting is 500-600 r / min, and the final centrifugal speed is 1300-1600 r / min.

[0034] Further, the high-toughness steel is one or more of 20 steel, 42CrMo steel, 35CrMo steel, 4Cr5MoSiV steel, and 40CrNiMo steel.

[0035] Further, in step 3): before the step of pouring the second metal liquid into the hob ring mold, the first metal liquid solidifies to form an outer ring, and the temperature inside the outer ring is 1350 - 1400 °C; and / or

[0036] The second metal liquid is poured into the hob ring mold by vertical centrifugal casting;

[0037] Preferably, the pouring temperature of the second metal liquid is 1500 - 1530 °C;

[0038] Preferably, the initial centrifugal rotation speed during vertical centrifugal casting is 500 - 600 r / min, and the final centrifugal rotation speed is 1300 - 1600 r / min.

[0039] On the other hand, the present invention provides a hob ring, which includes an inner ring, an outer ring, and a connection structure between the inner ring and the outer ring. The connection structure is in the shape of a "tu" character, and the material of the connection structure is a ceramic metal composite material; the upper end of the "tu" character of the connection structure is located inside the outer ring, and the lower end is located inside the inner ring; wherein, the inner ring is made of high-toughness steel, and the outer ring is made of high-hardness wear-resistant steel;

[0040] Preferably, the connection structure includes a preform in the shape of a "tu" character; preferably, a part of the preform is infiltrated and wrapped with the high-hardness wear-resistant steel, and another part of the preform is infiltrated and wrapped with the high-toughness steel;

[0041] Preferably, the microstructure of the inner ring includes ferrite and pearlite, the volume fraction of ferrite is 30 - 40%, and the volume fraction of pearlite is 60 - 70 wt%;

[0042] Preferably, the microstructure of the outer ring includes martensite, austenite, and carbides; the carbides include VC and M7C3; wherein, the volume fraction of martensite is 30 - 40%, the volume fraction of austenite is 10 - 20%, the volume fraction of VC is 30 - 40%, and the volume fraction of M7C3 is 15 - 20%;

[0043] Preferably, the microstructure of the preform includes a polycrystalline structure, and the grain size of the polycrystalline structure is 100 - 150 nm;

[0044] Preferably, the surface hardness of the hob ring is 65 - 68 HRC, the surface friction coefficient is 0.3 - 0.5, and the impact toughness is 5 - 8 J / cm 2 ;

[0045] Preferably, the hob cutter ring is obtained by using the preparation method described in any one of the above.

[0046] Compared with the prior art, the present invention has at least the following beneficial effects:

[0047] 1. The present invention provides a preparation method of a hob cutter ring. By placing a preform in the shape of a "soil" and made of a ceramic-metal composite material in a hob cutter ring mold, and then pouring the molten metal of high-hardness wear-resistant steel into the hob cutter ring mold, the molten metal of high-hardness wear-resistant steel fills the outer ring of the hob cutter ring mold, and at the same time infiltrates into the preform and wraps part of the preform; then pouring the molten metal of high-toughness steel into the hob cutter ring mold, the molten metal of high-hardness wear-resistant steel fills the inner ring of the hob cutter ring mold, and at the same time infiltrates into the preform and wraps another part of the preform, and then performing heat treatment and machining to obtain the hob cutter ring. Based on the above method, the preform of the ceramic composite material has the low-expansion characteristics of ceramics, which can reduce the direct contact area between the inner and outer rings (layers) of the two alloys (i.e., high-hardness wear-resistant steel and high-toughness steel). The two alloys are connected through the preform, and an expansion gradient is formed among the three, solving the problem of insufficient bonding strength caused by different expansion coefficients of the composite material during casting and cooling.

[0048] 2. Further, the "soil"-shaped preform connects the inner high-toughness steel and the outer high-hardness wear-resistant steel, pinning the stress at the joint between the high-toughness steel and the high-hardness wear-resistant steel to avoid stress concentration. The upper head of the "soil"-shaped preform (i.e., the free end of the vertical column) is located in the high-hardness wear-resistant steel, which is beneficial to transferring the impact stress received by the high-hardness wear-resistant steel to the inner high-toughness steel during service. Specifically, after the high-hardness steel stress is formed, the stress will be transmitted along the upper head of the "soil"-shaped preform to the lower horizontal line, which can prompt the inner high-toughness steel to better absorb the stress, thereby improving the fracture toughness of the cutter ring.

[0049] 3. Further, the present invention adopts a vertical centrifugal casting method. During casting, there are both centrifugal force and gravity. Therefore, when centrifugally rotating to the top, under the action of gravity and centrifugal force, the molten metal flows faster and more fully into the preform, improving the bonding strength between the molten metal and the preform. At the same time, the加持 of gravity also promotes the improvement of the bonding force between the inner and outer layers, further ensuring the bonding degree between the inner and outer layers.

[0050] 4. On the other hand, the present invention provides a hob cutter ring prepared by the above method. The hob cutter ring includes an inner ring, an outer ring, and a connection structure between the inner ring and the outer ring. The connection structure is in the shape of a Chinese character 'tu' (土), and the material of the connection structure is a ceramic metal composite material. The upper part of the 'tu'-shaped connection structure is located inside the outer ring, and the lower part is located inside the inner ring. Among them, the inner ring is made of high-toughness steel, and the outer ring is made of high-hardness and wear-resistant steel. The connection structure includes a preform in the shape of a 'tu'. A part of the preform is infiltrated and wrapped with high-hardness and wear-resistant steel, and another part of the preform is infiltrated and wrapped with high-toughness steel. The microstructure of the inner ring includes ferrite and pearlite. The volume fraction of ferrite is 30 - 40%, and the volume fraction of pearlite is 60 - 70wt%. The microstructure of the outer ring includes martensite, austenite, and carbides. The carbides include VC and M7C3. Among them, the volume fraction of martensite is 30 - 40%, the volume fraction of austenite is 10 - 20%, the volume fraction of VC is 30 - 40%, and the volume fraction of M7C3 is 15 - 20%. The high-toughness steel of the inner layer (inner ring) is beneficial to ensuring that the cutter ring has high fracture toughness, and the high-hardness and wear-resistant steel of the outer layer (outer ring) is beneficial to ensuring that the surface of the cutter ring has high hardness and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings in the following description are merely exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0052] Figure 1 Schematic flow chart for preparing the hob cutter ring in Example 1;

[0053] Figure 2 Microstructure morphology diagram of the cross-section of the hob cutter ring prepared in Example 2;

[0054] Figure 3 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Comparative Example 1 and Example 1;

[0055] Figure 4 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Example 3 and Example 1;

[0056] Figure 5 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Example 4 and Example 1;

[0057] Figure 6 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Example 5 and Example 1;

[0058] Figure 7Microstructure morphology map of the near surface of the hob cutter ring prepared in Example 6;

[0059] Figure 8 Schematic diagram of the wear resistance comparison of the hob cutter rings prepared in Example 6 and Example 1;

[0060] Fig. 9 Microstructure morphology map at the interface of the hob cutter rings prepared in Comparative Example 2 and Example 1;

[0061] Fig.10 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Comparative Example 2 and Example 1. Detailed implementation manners

[0062] In order to more clearly illustrate the implementation manners of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the implementation manners or the prior art. The drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained by extending according to the provided drawings.

[0063] A preparation method of a hob cutter ring includes the following steps:

[0064] Step 1) Mix ceramic powder, metal powder and volatile solvent to obtain ceramic slurry; perform centrifugal spray drying treatment on the ceramic slurry to obtain ceramic-metal composite powder; mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to obtain a preform; wherein, the preform is in the shape of "soil", and the material of the preform is a ceramic-metal composite material; the thickness of the preform is 5 - 8 mm; the length of the preform is 3 - 5 cm; the width of the preform is 2 - 5 mm; wherein, the length of the preform refers to the length of the vertical column of the "soil"-shaped preform; the width of the preform refers to the width of the bottom cross column of the "soil"-shaped preform;

[0065] Among them, the punch of the tablet press is in the shape of "soil"; the mass ratio of the ceramic powder to the metal powder is 8:1 - 10:1; the addition amount of the volatile solvent is 0.3 - 0.5% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 10% - 25% of the total mass of the ceramic powder and the metal powder; preferably, the ceramic powder is one or more of WC powder, TiC powder, B4C powder, TiN powder; the particle size of the ceramic powder is 250 - 500 mesh;

[0066] The metal powder is a mixed powder of high-toughness steel powder and high-hardness wear-resistant steel powder; preferably, the mass ratio of high-toughness steel powder to high-hardness wear-resistant steel powder is 1:1-1.5:1; preferably, the high-toughness steel powder is one or more of 20 steel, 42CrMo steel powder, 35CrMo steel powder, 4Cr5MoSiV steel powder, and 40CrNiMo steel powder; preferably, the high-hardness wear-resistant steel powder is a steel powder with a hardness of HRC68 or above; in terms of mass percentage, the composition of the high-hardness wear-resistant steel powder is: C: 3-3.5wt%, V: 7-9w t%, Mo: 1.5-3wt%, Si: 1-1.5wt%, Mn: 0.2-0.5wt%, Ni: 1-3wt%, N: 0.1-0.3wt%, W: 2-3wt%, Al: 0.5-0.8wt%, Co: 1-1.5wt%, Nb: 0.5-1wt%, and the balance is Fe; the volatile solvent is acetone or alcohol, which has strong solubility for the mixed powder, is conducive to the separation and recombination between particles, and is conducive to the homogenization of the metal powder;

[0067] Among them, if the thickness of the preform is too large, it will occupy a larger space at the interface of the inner and outer metal layers (the inner layer of high-toughness steel and the outer layer of high-hardness wear-resistant steel), resulting in insufficient bonding between the inner and outer layers, and at the same time hindering the fluidity of the inner and outer metal liquid during casting, resulting in a large number of defects inside the cutter ring; if the thickness of the preform is too small, during the subsequent vertical centrifugal casting, more parts of the ceramic will be burned, resulting in an incomplete preform in the casting, which will reduce the bonding ability between the two metals on the one hand, and reduce its role in transmitting stress to the internal high-toughness alloy steel on the other hand, thereby reducing the compressive strength and impact toughness of the cutter ring;

[0068] Step 2) placing a plurality of preforms in a cutter ring mold, and then pouring a high-hardness wear-resistant steel molten metal (first molten metal) into the cutter ring mold by a vertical centrifugal casting method, so that the high-hardness wear-resistant steel molten metal fills the outer ring of the cutter ring mold, and at the same time infiltrates into the preform, and wraps a part of the preform (that is, a part of the preform is located in the first molten metal, preferably, the "earth"-shaped upper end horizontal column and the vertical column above the upper end horizontal column are located in the first molten metal);

[0069] Among them, the spacing angle between two adjacent preforms in the plurality of preforms is 10-20°; the hardness of the high-hardness wear-resistant steel is HRC68 or above; the carbon content of the high-hardness wear-resistant steel is 3-4.5wt%; the alloy content of the high-hardness wear-resistant steel is 30-40wt%; in terms of mass percentage, the composition of the high-hardness wear-resistant steel is: C: 3-3.5wt%, V: 7-9wt%, Mo: 1.5-3wt%, Si: 1-1.5wt%, Mn: 0.2-0.5 wt%, Ni: 1-3wt%, N: 0.1-0.3wt%, W: 2-3wt%, Al: 0.5-0.8wt%, Co: 1-1.5wt%, Nb: 0.5-1wt%, and the balance is Fe; the pouring temperature of the molten metal of the high hardness and wear-resistant steel is 1530-1550°C; preferably, the initial centrifugal speed during vertical centrifugal casting is 500-600r / min, and the final centrifugal speed is 1300-1600r / min;

[0070] The spacing angle between two adjacent preforms refers to the spacing angle between the centers of the two preforms. The spacing angle between two adjacent preforms determines the number of preforms. If the spacing angle is large, the number is small, and the supporting effect of the preforms on the super-hard wear-resistant steel is reduced, and the stress of the outer layer cannot be better transferred to the inner layer, which is not conducive to the impact toughness of the cutter ring;

[0071] refer to Figure 1 It can be seen that multiple preforms are evenly distributed in the hob cutter ring mold along the circumferential direction; the free end of the "earth"-shaped vertical column of the preform is away from the center of the hob cutter ring mold and faces the outer ring of the hob cutter ring mold; preferably, after pouring, the high-hardness wear-resistant steel is filled to the center line position of the hob cutter tool (see Figure 1 ),

[0072] Step 3) The molten metal of the super-hard wear-resistant steel solidifies to form an outer ring. When the temperature of the inner side of the outer ring is cooled to 1350-1400°C, the molten metal of the high-toughness steel (the second molten metal) is poured into the hob cutter ring mold by a vertical centrifugal casting method, so that the molten metal of the high-hard wear-resistant steel fills the inner ring of the hob cutter ring mold and infiltrates into the preform at the same time, and wraps another part of the preform, and then performs heat treatment and machining to obtain the hob cutter ring;

[0073] Among them, the inner side of the outer ring refers to the side of the molten metal of the ultra-hard wear-resistant steel close to the center of the hob ring. When it is cooled to 1350-1400 °C, the molten metal of the high-hard wear-resistant steel has solidified, and the temperature can be measured by a thermocouple; and at this temperature, the solidification shrinkage of the outer-layer alloy can be preferentially released, which can effectively ensure its metallurgical bonding with the preform and the inner-layer high-toughness steel; when the temperature is higher than 1400 °C, the outer-layer metal has not completely solidified and cooled and shrunk. Therefore, when pouring the inner-layer high-toughness steel, it will solidify and shrink simultaneously with the inner layer, and cavities will be formed at the interface; when the temperature is lower than 1350 °C, the shrinkage stress of the outer-layer ultra-hard wear-resistant steel is relatively large, resulting in too large bonding stress between the ultra-hard wear-resistant steel and the ceramic, while the bonding force between the subsequently cast high-toughness steel and the ceramic is insufficient;

[0074] Among them, the high-toughness steel is one or several of 20 steel, 42CrMo steel, 35CrMo steel, 4Cr5MoSiV steel, 40CrNiMo steel; the pouring temperature of the molten metal of the high-hard wear-resistant steel is 1530-1550 °C; the initial centrifugal rotation speed during vertical centrifugal casting is 500-600 r / min, and the final centrifugal rotation speed is 1300-1600 r / min;

[0075] Among them, the heat treatment includes normalizing heat treatment and tempering heat treatment carried out in sequence; among them, the temperature of the normalizing heat treatment is 850-1100 °C, and the time of the normalizing heat treatment is 2-3 h; the temperature of the tempering heat treatment is 250-270 °C, and the time of the tempering heat treatment is 2-3 h; the machining is mainly lathe turning and grinding and polishing.

[0076] Based on the above method, the "T"-shaped preform made of ceramic-metal composite material has the low-expansion characteristics of ceramics, which can reduce the direct contact area between the inner and outer rings (layers) of the two alloys (i.e., high-hard wear-resistant steel and high-toughness steel). The two alloys are connected through the preform, and an expansion gradient is formed among the three, solving the problem of insufficient bonding strength of the composite material due to different expansion coefficients during casting and cooling.

[0077] Furthermore, the "T"-shaped preform connects the inner-layer high-toughness steel and the outer-layer high-hard wear-resistant steel, pins the stress at the joint of the high-toughness steel and the high-hard wear-resistant steel, and avoids stress concentration. The upper head (i.e., the free end of the vertical column) of the "T"-shaped preform is located in the high-hard wear-resistant steel, which is beneficial to transferring the impact stress received by the high-hard wear-resistant steel to the inner-layer high-toughness steel during service. Specifically, after the high-hard steel stress is formed, the stress will be transferred along the upper head of the "T"-shaped preform to the lower horizontal line, which can prompt the inner-layer high-toughness steel to better absorb the stress, thereby improving the fracture toughness of the hob ring.

[0078] On the other hand, the present invention provides a hob cutter ring obtained by using the preparation method of any one of the above. The hob cutter ring includes an inner ring, an outer ring, and a connection structure between the inner ring and the outer ring. The connection structure includes a "soil"-shaped preform, and the material of the preform is a ceramic-metal composite material; the upper end of the "soil" shape of the preform is located inside the outer ring, and the lower end is located inside the inner ring; wherein, the inner ring is made of high-toughness steel, and the outer ring is made of high-hardness wear-resistant steel;

[0079] Wherein, a part of the preform is infiltrated and wrapped with the high-hardness wear-resistant steel, and another part of the preform is infiltrated and wrapped with the high-toughness steel;

[0080] The microstructure of the inner ring includes ferrite and pearlite. The volume fraction of ferrite is 30-40%, and the volume fraction of the pearlite is 60-70wt%; the microstructure of the outer ring includes martensite, austenite, and carbides; the carbides include VC and M7C3; wherein, the volume fraction of martensite is 30-40%, the volume fraction of austenite is 10-20%, the volume fraction of VC is 30-40%, and the volume fraction of M7C3 is 15-20%; the microstructure of the preform includes a polycrystalline structure, and the grain size of the polycrystalline structure is 100-150nm;

[0081] The surface hardness of the hob cutter ring is 65-68HRC, the surface friction coefficient is 0.3-0.5, and the impact toughness is 5-8J / cm 2 。

[0082] The present invention will be further described below with specific examples and comparative examples.

[0083] Example 1

[0084] This example provides a preparation method of a hob cutter ring. The preparation process is as Figure 1 shown, and specifically includes the following steps:

[0085] Step 1) Ball-mill and mix TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol, and perform centrifugal spray drying on the ceramic slurry obtained after ball milling to obtain a ceramic-metal composite powder; mix the ceramic-metal composite powder with an adhesive and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 6mm and a length of about 4cm;

[0086] Wherein, in terms of mass percentage, the high-hardness wear-resistant steel powder includes: C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the mass ratio of ceramic powder to metal powder is 9:1; the amount of alcohol added is 0.4% of the total mass of the ceramic powder and the metal powder; the amount of adhesive added is 15% of the total mass of the ceramic powder and the metal powder;

[0087] Step 2) placing a plurality of the above-mentioned preforms in a hob cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the plurality of preforms are away from the center of the hob cutter ring mold and toward the outer ring of the hob cutter ring mold; the plurality of the preforms are evenly distributed along the circumference of the hob cutter ring mold; and the spacing angle between two adjacent preforms is 15°;

[0088] Melting the first molten metal, pouring the first molten metal into the mold of the cutter ring by a vertical centrifugal casting method, so that the first molten metal infiltrates into the preform and wraps a part of the preform; when pouring to the center line position of the cutter ring mold, stopping pouring;

[0089] The first molten metal is a molten metal of high-hardness wear-resistant steel; in terms of mass percentage, the high-hardness wear-resistant steel includes: C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the pouring temperature is 1540°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min;

[0090] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel is cooled to 1380°C, pour the molten metal of 20 steel (the second molten metal) to allow the molten metal to infiltrate the preform and wrap another part of the preform until the cutter ring mold is filled, and then perform heat treatment and machining to obtain the hob cutter ring; wherein the pouring temperature is 1530°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min.

[0091] Example 2

[0092] This embodiment provides a method for preparing a hob cutter ring, which specifically includes the following steps:

[0093] Step 1) Ball mill and mix WC ceramic powder, high-hardness wear-resistant steel powder, 42CrMo steel powder, alcohol, etc. Centrifugally spray-dry the ceramic slurry obtained after ball milling to obtain ceramic-metal composite powder; Mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 6 mm and a length of about 5 cm;

[0094] Among them, by mass percentage, the high-hardness wear-resistant steel powder includes: C: 3.3 wt%, V: 8.5 wt%, Mo: 2.2 wt%, Si: 1.3 wt%, Mn: 0.4 wt%, Ni: 2.1 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.75 wt%, Co: 1.3 wt%, Nb: 0.8 wt%, and the balance is Fe; The mass ratio of the ceramic powder to the metal powder is 8:1; The addition amount of alcohol is 0.35% of the total mass of the ceramic powder and the metal powder; The addition amount of the binder is 20% of the total mass of the ceramic powder and the metal powder;

[0095] Step 2) Place multiple above-mentioned preforms in a hob ring die; Among them, the free ends of the vertical columns of the "soil"-shaped of multiple preforms are far from the center of the hob ring die and face the outer ring of the hob ring die; Multiple said preforms are evenly distributed along the circumferential direction of the hob ring die; The interval angle between adjacent two preforms is 10°;

[0096] Melt the first metal liquid, and use the vertical centrifugal casting method to pour the first metal liquid into the die of the hob ring, so that the first metal liquid infiltrates into the preform and wraps part of the preform; When pouring to the midline position of the hob ring die, stop pouring;

[0097] Among them, the first metal liquid is the metal liquid of high-hardness wear-resistant steel; By mass percentage, the high-hardness wear-resistant steel includes: C: 3.3 wt%, V: 8.5 wt%, Mo: 2.2 wt%, Si: 1.3 wt%, Mn: 0.4 wt%, Ni: 2.1 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.75 wt%, Co: 1.3 wt%, Nb: 0.8 wt%, and the balance is Fe; The pouring temperature is 1530 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min;

[0098] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1400 °C, pour the metal liquid (the second metal liquid) of 42CrMo steel, so that the metal liquid infiltrates into the preform and wraps part of the preform until the hob ring die is filled, and then perform heat treatment and machining to obtain a hob ring; Among them, the pouring temperature is 1520 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min.

[0099] The cross-sectional microstructure morphology of the hob cutter ring prepared in this embodiment is as Figure 2 shown. It can be seen that there is a metallurgical bond between the outer high-hardness wear-resistant steel and 42CrMo, and the structure at the interface is dense and defect-free; at the same time, there is also a metallurgical bond between the preform and the two high-hardness wear-resistant steels and 42CrMo, and the bonding condition is good.

[0100] Comparative Example 1

[0101] This comparative example provides a preparation method for a hob cutter ring, which specifically includes the following steps:

[0102] Step 1) Ball-mill and mix TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol, and perform centrifugal spray drying on the ceramic slurry obtained after ball milling to obtain a ceramic-metal composite powder; mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 6 mm and a length of about 4 cm;

[0103] Among them, in terms of mass percentage, the high-hardness wear-resistant steel powder includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the mass ratio of the ceramic powder to the metal powder is 9:1; the addition amount of alcohol is 0.4% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 15% of the total mass of the ceramic powder and the metal powder;

[0104] Step 2) Place multiple above-mentioned preforms in a hob cutter ring mold; among them, the free ends of the vertical columns of the "soil" shape of the multiple preforms are far from the center of the hob cutter ring mold and face the outer ring of the hob cutter ring mold; the multiple preforms are evenly distributed along the circumferential direction of the hob cutter ring mold; the interval angle between adjacent two preforms is 15°;

[0105] Melt the metal liquid of the high-hardness wear-resistant steel, and use the vertical centrifugal casting method to pour the metal liquid of the high-hardness wear-resistant steel into the mold of the cutter ring to make the metal liquid infiltrate into the preform;

[0106] Among them, in terms of mass percentage, the high-hardness wear-resistant steel includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the pouring temperature is 1540 °C, the initial centrifugal rotation speed is 550 r / min, and the final centrifugal rotation speed is 1550 r / min.

[0107] The comparison of the compressive strength and impact toughness of the hob cutter rings prepared in this comparative example and Example 1 is as follows Figure 3 As shown, this comparative example is prepared by single-metal centrifugal casting. Since there is a lack of high-toughness steel inside, the impact toughness of this comparative example is significantly lower than that of the alloy of the present invention, and the impact toughness is only 1 / 3 of the cutter ring of Example 1 of the present invention.

[0108] Examples 1 and 2 are preferred examples that adopt the essential features and preferred technical features of the present invention. The following several examples are examples that adopt the essential features and non-preferred technical features.

[0109] Example 3

[0110] This example provides a preparation method for a hob cutter ring, which specifically includes the following steps:

[0111] Step 1) Ball-mill and mix TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol. Centrifugally spray-dry the ceramic slurry obtained after ball milling to obtain ceramic-metal composite powder; mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 6 mm and a length of about 4 cm;

[0112] Among them, by mass percentage, the high-hardness wear-resistant steel powder includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the mass ratio of the ceramic powder to the metal powder is 9:1; the addition amount of alcohol is 0.4% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 15% of the total mass of the ceramic powder and the metal powder;

[0113] Step 2) Place multiple above-mentioned preforms in a hob cutter ring mold; among them, the free ends of the vertical columns of the "soil"-shaped of multiple preforms are far from the center of the hob cutter ring mold and face the outer ring of the hob cutter ring mold; multiple said preforms are evenly distributed along the circumferential direction of the hob cutter ring mold; the interval angle between two adjacent preforms is 15°;

[0114] Melt to obtain the first metal liquid, and use the horizontal centrifugal casting method to pour the first metal liquid into the mold of the cutter ring, so that the first metal liquid infiltrates into the preform and wraps part of the preform; when pouring to the center line position of the cutter ring mold, stop pouring;

[0115] Among them, the first molten metal is the molten metal of high-hardness wear-resistant steel; by mass percentage, the high-hardness wear-resistant steel includes: C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the pouring temperature is 1540 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min;

[0116] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1380 °C, pour the molten metal of 20 steel (the second molten metal) so that the molten metal infiltrates into the preform until the cutter ring mold is filled, and then perform heat treatment and machining to obtain a hob cutter ring; among them, the pouring temperature is 1530 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min.

[0117] The comparison of the compressive strength and impact toughness of the hob cutter rings prepared in this example and Example 1 is as Figure 4 shown. It can be seen that in this example, the cutter ring is prepared by the horizontal centrifugal casting process, lacking the top gravity加持 effect during vertical centrifugal casting, resulting in a poor bonding force problem at the outer layer of the cutter ring and the metal-ceramic interface. Therefore, the compressive strength and impact toughness of this example are both lower than those of Example 1 of the present invention.

[0118] Example 4

[0119] This example provides a preparation method for a hob cutter ring, which specifically includes the following steps:

[0120] Step 1) Ball-mill and mix TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol, and perform centrifugal spray drying on the ceramic slurry obtained after ball milling to obtain ceramic-metal composite powder;

[0121] Mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 3 mm and a length of about 4 cm;

[0122] Among them, by mass percentage, the high-hardness wear-resistant steel powder includes: C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the mass ratio of the ceramic powder to the metal powder is 9:1; the addition amount of alcohol is 0.4% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 15% of the total mass of the ceramic powder and the metal powder;

[0123] Step 2) placing a plurality of the above-mentioned preforms in a hob cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the plurality of preforms are away from the center of the hob cutter ring mold and toward the outer ring of the hob cutter ring mold; the plurality of the preforms are evenly distributed along the circumference of the hob cutter ring mold; and the spacing angle between two adjacent preforms is 15°;

[0124] Melting the first molten metal, pouring the first molten metal into the mold of the cutter ring by a vertical centrifugal casting method, so that the first molten metal infiltrates into the preform and wraps a part of the preform; when pouring to the center line position of the cutter ring mold, stopping pouring;

[0125] The first molten metal is a molten metal of high-hardness wear-resistant steel; in terms of mass percentage, the high-hardness wear-resistant steel includes: C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the pouring temperature is 1540°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min;

[0126] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel is cooled to 1380°C, pour molten metal (second molten metal) of 20 steel to allow the molten metal to infiltrate the preform and wrap another part of the preform until the cutter ring mold is filled, and then perform heat treatment and machining to obtain the hob cutter ring; wherein the pouring temperature is 1530°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min.

[0127] The compressive strength and impact toughness of the hob cutter ring prepared in this embodiment and in Example 1 are compared. Figure 5 As shown, it can be seen that the thickness of the preform in this embodiment is relatively small. During vertical centrifugal casting, more parts of the ceramic are burned, resulting in an incomplete preform in the casting. On the one hand, the bonding ability between the inner and outer layers is reduced, and on the other hand, its effect of transmitting stress to the internal high-toughness alloy steel is reduced, thereby reducing the compressive strength and impact toughness of the cutter ring.

[0128] Example 5

[0129] This embodiment provides a method for preparing a hob cutter ring, which specifically includes the following steps:

[0130] Step 1) ball-milling TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder and alcohol, and centrifugally spray-drying the ceramic slurry obtained after ball milling to obtain ceramic-metal composite powder;

[0131] Mix the ceramic-metal composite powder with the binder and fill it into an automatic tablet press to prepare a preform in the shape of a "soil" character with a thickness of 6 mm and a length of about 4 cm;

[0132] Among them, by mass percentage, the high-hardness wear-resistant steel powder includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the mass ratio of the ceramic powder to the metal powder is 9:1; the addition amount of alcohol is 0.4% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 15% of the total mass of the ceramic powder and the metal powder;

[0133] Step 2) Place multiple above-mentioned preforms in a hob ring die; among them, the free ends of the vertical columns of the "soil" character of multiple preforms are far from the center of the hob ring die and face the outer ring of the hob ring die; multiple said preforms are evenly distributed along the circumferential direction of the hob ring die; the interval angle between adjacent two preforms is 30°;

[0134] Melt the first metal liquid, and use the vertical centrifugal casting method to pour the first metal liquid into the die of the cutter ring, so that the first metal liquid infiltrates into the preform and wraps part of the preform; when pouring to the midline position of the cutter ring die, stop pouring;

[0135] Among them, the first metal liquid is the metal liquid of high-hardness wear-resistant steel; by mass percentage, the high-hardness wear-resistant steel includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the pouring temperature is 1540 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min;

[0136] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1380 °C, pour the metal liquid of 20 steel (the second metal liquid) so that the metal liquid infiltrates into the preform and wraps another part of the preform until the cutter ring die is filled, and then perform heat treatment and machining to obtain a hob cutter ring; among them, the pouring temperature is 1530 °C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / min.

[0137] The comparison of the compressive strength and impact toughness of the hob cutter rings prepared in this example and Example 1 is as follows Figure 6As shown, it can be seen that in this embodiment, the interval angle between the preforms is relatively large, so the number is small. The supporting effect of the preforms on the ultra-hard wear-resistant steel is reduced, and the stress of the outer layer cannot be better transmitted to the inner layer, reducing the impact toughness of the cutter head.

[0138] Example 6

[0139] This embodiment provides a preparation method for a hob cutter head, which specifically includes the following steps:

[0140] Step 1) Ball-mill and mix TiC ceramic powder, high-hard wear-resistant steel powder, 20 steel powder, and alcohol, and perform centrifugal spray drying on the ceramic slurry obtained after ball milling to obtain ceramic-metal composite powder;

[0141] Mix the ceramic-metal composite powder with a binder and fill it into an automatic tablet press to prepare a "soil"-shaped preform with a thickness of 6 mm and a length of about 4 cm;

[0142] Among them, by mass percentage, the high-hard wear-resistant steel powder includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the mass ratio of the ceramic powder to the metal powder is 9:1; the addition amount of alcohol is 0.4% of the total mass of the ceramic powder and the metal powder; the addition amount of the binder is 15% of the total mass of the ceramic powder and the metal powder;

[0143] Step 2) Place multiple above-mentioned preforms in a hob cutter head mold; among them, the free ends of the vertical columns of the "soil"-shaped of the multiple preforms are far from the center of the hob cutter head mold and face the outer ring of the hob cutter head mold; the multiple preforms are evenly distributed along the circumferential direction of the hob cutter head mold; the interval angle between adjacent two preforms is 15°;

[0144] Melt to obtain the first metal liquid, and use the vertical centrifugal casting method to pour the first metal liquid into the mold of the cutter head, so that the first metal liquid infiltrates into the preform and wraps part of the preform; when pouring to the middle line position of the cutter head mold, stop pouring;

[0145] Among them, the first metal liquid is the metal liquid of high-hard wear-resistant steel; by mass percentage, the high-hard wear-resistant steel includes: C: 3 wt%, V: 7.5 wt%, Mo: 1.6 wt%, Si: 1.2 wt%, Mn: 0.3 wt%, Ni: 2 wt%, N: 0.2 wt%, W: 2.5 wt%, Al: 0.6 wt%, Co: 1.4 wt%, Nb: 0.8 wt%, and the balance is Fe; the pouring temperature is 1540 °C, the initial centrifugal rotation speed is 300 r / min, and the final centrifugal rotation speed is 1450 r / min;

[0146] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel is cooled to 1380°C, pour molten metal of 20 steel to allow the molten metal to infiltrate the preform until the cutter ring mold is filled, and then perform heat treatment and machining to obtain the hob cutter ring; wherein the pouring temperature is 1530°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min.

[0147] The near-surface microstructure morphology of the hob cutter ring prepared in this embodiment is compared. Figure 7 As shown in the figure, the compressive strength and impact toughness of the hob cutter ring prepared in Example 1 are compared. Figure 8 As shown, it can be seen that the initial centrifugal casting speed in this embodiment is low, resulting in insufficient driving force for the molten metal, and defects such as holes appear between the high-hardness wear-resistant steel, high-toughness steel and the preform, which in turn leads to a decrease in the wear resistance of the cutter ring.

[0148] Comparative Example 2

[0149] This comparative example provides a method for preparing a hob cutter ring, and the preparation process is as follows: Figure 1 As shown, the specific steps include:

[0150] Step 1) melting a first molten metal, and pouring the first molten metal into a mold of a cutter ring by a vertical centrifugal casting method. When the first molten metal reaches the center line of the cutter ring mold, the pouring is stopped;

[0151] The first molten metal is a molten metal of high-hardness wear-resistant steel; in terms of mass percentage, the high-hardness wear-resistant steel includes C: 3wt%, V: 7.5wt%, Mo: 1.6wt%, Si: 1.2wt%, Mn: 0.3wt%, Ni: 2wt%, N: 0.2wt%, W: 2.5wt%, Al: 0.6wt%, Co: 1.4wt%, Nb: 0.8wt%, and the balance is Fe; the pouring temperature is 1540°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min;

[0152] Step 2) When the inner surface temperature of the high-hardness wear-resistant steel is cooled to 1380°C, pour the molten metal (second molten metal) of 20 steel until the cutter ring mold is filled, and then perform heat treatment and machining to obtain the hob cutter ring; wherein the pouring temperature is 1530°C, the initial centrifugal speed is 550r / min, and the final centrifugal speed is 1550r / min.

[0153] Fig. 9 The morphology of the inner and outer metal interfaces of Example 1 and Comparative Example 2, and the mechanical properties of the two are as follows Fig.10As shown, it can be found that since there is no preform in this comparative example, the shrinkage coefficients of the inner and outer metal layers are different when cooling, and cracks are easily formed at the interface, which is not conducive to improving the toughness of the cutter ring.

[0154] It is easy for those skilled in the art to understand that, without conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0155] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing a hob cutter ring, characterized in that: It includes the following steps: Step 1) Prepare a preform. The preform is in the shape of "soil", and the material of the preform is a ceramic-metal composite material. Step 2) Place multiple preforms in a hob ring die, and then pour a first metal liquid into the hob ring die, so that the first metal liquid fills the outer ring of the hob ring die, and at the same time infiltrates into the preform and wraps a part of the preform. Step 3) Pour a second metal liquid into the hob ring die, so that the second metal liquid fills the inner ring of the hob ring die, and at the same time infiltrates into the preform and wraps another part of the preform, and then perform heat treatment and machining to obtain a hob ring. Wherein, the first metal liquid is a metal liquid of high-hardness wear-resistant steel, and the second metal liquid is a metal liquid of high-toughness steel.

2. The method for preparing a hob cutter ring according to claim 1, characterized in that: In the step 1), the steps of preparing the preform include: Mix the raw materials to obtain a ceramic slurry; make the ceramic slurry into a ceramic-metal composite powder; mix the ceramic-metal composite powder with a binder, and then perform pressing treatment to obtain the preform. Wherein, the raw materials include ceramic powder, metal powder and a volatile solvent. Preferably, the volatile solvent is acetone or alcohol. Preferably, the ceramic slurry is made into a ceramic-metal composite powder by centrifugal spray drying treatment. Preferably, the pressing treatment is carried out in a tablet press. Preferably, the pressing head of the tablet press is in the shape of "soil". Further preferably, the tablet press is an automatic tablet press.

3. The method for preparing a hob cutter ring according to claim 2, characterized in that: In the raw materials: the mass ratio of the ceramic powder to the metal powder is 8:1 to 10:1; and / or The ceramic powder is one or more of WC powder, TiC powder, B4C powder, TiN powder; and / or The particle size of the ceramic powder is 250 to 500 mesh; and / or The addition amount of the volatile solvent is 0.3 to 0.5% of the total mass of the ceramic powder and the metal powder; and / or The addition amount of the binder is 10% to 25% of the total mass of the ceramic powder and the metal powder; and / or The metal powder is a mixed powder of high-toughness steel powder and high-hardness wear-resistant steel powder. Preferably, the mass ratio of the high-toughness steel powder to the high-hardness wear-resistant steel powder is 1:1 to 1.5:

1. Preferably, the high-toughness steel powder is one or more of 20 steel, 42CrMo steel powder, 35CrMo steel powder, 4Cr5MoSiV steel powder, 40CrNiMo steel powder. Preferably, the high-hardness wear-resistant steel powder is a steel powder with a hardness above HRC68.

4. The method for preparing a hob cutter ring according to claim 1, characterized in that: The thickness of the preform is 5 to 8 mm; the length of the preform is 3 to 5 cm; the width of the preform is 2 to 5 mm.

5. The method for preparing a hob cutter ring according to claim 1, characterized in that: In the step 2): The free ends of the vertical columns of the "soil" shape of multiple preforms are far from the center of the hob ring die and face the outer ring of the hob ring die; and / or Multiple preforms are evenly distributed along the circumferential direction of the hob ring die; and / or Among multiple preforms, the included angle between two adjacent preforms is 10 to 20°.

6. The method for preparing a hob cutter ring according to claim 1, characterized in that: The hardness of the high-hardness wear-resistant steel is above HRC68; and / or The carbon content of the high-hardness wear-resistant steel is 3 to 4.5 wt%; and / or The alloy content of the high-hardness wear-resistant steel is 30-40 wt%; and / or By mass percentage, the composition of the high-hardness wear-resistant steel is: C: 3-3.5 wt%, V: 7-9 wt%, Mo: 1.5-3 wt%, Si: 1-1.5 wt%, Mn: 0.2-0.5 wt%, Ni: 1-3 wt%, N: 0.1-0.3 wt%, W: 2-3 wt%, Al: 0.5-0.8 wt%, Co: 1-1.5 wt%, Nb: 0.5-1 wt%, and the balance is Fe.

7. The method for preparing a hob cutter ring according to claim 1, characterized in that: In the step 2): The first metal liquid is poured into the hob ring mold by vertical centrifugal casting method; Preferably, the pouring temperature of the first metal liquid is 1530-1550 °C; Preferably, the initial centrifugal speed during vertical centrifugal casting is 500-600 r / min, and the final centrifugal speed is 1300-1600 r / min.

8. The method for preparing a hob cutter ring according to claim 1, characterized in that: The high-toughness steel is one or more of 20 steel, 42CrMo steel, 35CrMo steel, 4Cr5MoSiV steel, 40CrNiMo steel.

9. The method for preparing a hob cutter ring according to claim 1, characterized in that: In the step 3): Before the step of pouring the second metal liquid into the hob ring mold, the first metal liquid solidifies to form an outer ring, and the temperature inside the outer ring is 1350-1400 °C; and / or The second metal liquid is poured into the hob ring mold by vertical centrifugal casting method; Preferably, the pouring temperature of the second metal liquid is 1500-1530 °C; Preferably, the initial centrifugal speed during vertical centrifugal casting is 500-600 r / min, and the final centrifugal speed is 1300-1600 r / min.

10. A hob cutter ring, characterized in that: The hob ring includes an inner ring, an outer ring and a connecting structure between the inner ring and the outer ring. The connecting structure is in the shape of "soil", and the material of the connecting structure is a ceramic metal composite material; the upper end of the "soil"-shaped connecting structure is located inside the outer ring, and the lower end is located inside the inner ring; wherein, the inner ring is made of high-toughness steel, and the outer ring is made of high-hardness wear-resistant steel; Preferably, the connecting structure includes a preform in the shape of "soil"; preferably, a part of the preform is infiltrated and wrapped with the high-hardness wear-resistant steel, and the other part of the preform is infiltrated and wrapped with the high-toughness steel; Preferably, the microstructure of the inner ring includes ferrite and pearlite. The volume fraction of ferrite is 30-40%, and the volume fraction of pearlite is 60-70 wt%; Preferably, the microstructure of the outer ring includes martensite, austenite and carbides; the carbides include VC and M7C3; among them, the volume fraction of martensite is 30-40%, the volume fraction of austenite is 10-20%, the volume fraction of VC is 30-40%, and the volume fraction of M7C3 is 15-20%; Preferably, the microstructure of the preform includes a polycrystalline structure, and the grain size of the polycrystalline structure is 100-150 nm; Preferably, the surface hardness of the hob cutter ring is 65-68HRC, the surface friction coefficient is 0.3-0.5, and the impact toughness is 5-8J / cm 2 ; Preferably, the hob ring is obtained by the preparation method according to any one of claims 1-9.

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