Hob cutter ring and preparation method thereof

Abstract

The present invention provides a hob cutter ring and a preparation method thereof, which relates to the technical field of metal composite centrifugal casting, and comprises the following steps: preparing a preform, wherein the material of the preform is a ceramic-metal composite material; placing multiple preforms in a hob cutter ring mold, and then pouring a first molten metal into the hob cutter ring mold, so that the first molten metal fills the outer ring of the hob cutter ring mold, and at the same time infiltrates into the preform and wraps a portion of the preform; pouring a second molten metal into the hob cutter ring mold, so that the second molten metal fills the inner ring of the hob cutter ring mold, and at the same time infiltrates into the preform and wraps another portion of the preform, and then heat treating and machining to obtain the hob cutter ring. The preform of the present invention has the low expansion characteristics of ceramics, can reduce the area of ​​direct contact between the two alloys of the inner and outer rings (layers), connects the two alloys through the preform, forms an expansion gradient between the three, and solves the problem of insufficient bonding strength.

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 field of construction machinery, a shield machine has high technical complexity and high product added value. It is a "major national equipment" 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 rocks. During tunneling, it directly contacts the rock surface and bears the thrust and torque from the cutter head. However, due to the harsh working environment, the hob often experiences failure forms such as chipping, fracture, and non-uniform wear during operation, and the complex underground environment also causes 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 shedding, 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 a low bonding strength, cracks appearing at the bonding part, 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 for a hob cutter ring, comprising the following steps:

[0006] Step 1) Prepare a preform. The preform is in the shape of a "soil" character, 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 circle 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) pouring a second molten metal into the hob cutter ring mold, allowing the second molten metal to fill the inner ring of the hob cutter ring mold and simultaneously infiltrate the preform and wrap another portion of the preform, followed by heat treatment and machining to obtain the hob cutter ring;

[0009] The first molten metal is made of high-hardness and wear-resistant steel, and the second molten metal is made of high-toughness steel.

[0010] Furthermore, in step 1), the step of preparing the preform includes:

[0011] Mixing raw materials to obtain ceramic slurry; preparing ceramic-metal composite powder from the ceramic slurry; mixing the ceramic-metal composite powder with a binder, and then performing a pressing process 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 prepared into ceramic-metal composite powder by centrifugal spray drying;

[0015] Preferably, the pressing process is carried out in a tablet press; preferably, the pressing head of the tablet press is a "earth"-shaped structure; further preferably, the tablet press is an automatic tablet press.

[0016] Furthermore, 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, and TiN powder; and / or

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

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

[0020] The amount of the binder added is 10% to 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 1:1~1.5:1; 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 5-8 mm; the length of the preform is 3-5 cm; and the width of the preform is 2-5 mm.

[0023] Furthermore, in step 2):

[0024] 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 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 HRC68 or above; and / or

[0028] High-hardness wear-resistant steel with a carbon content of 3-4.5wt%; and / or

[0029] High hardness wear-resistant steel with an alloy content of 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 using a vertical centrifugal casting method;

[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 speed during vertical centrifugal casting is 500 - 600 r / min, and the final centrifugal 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 any of the preparation methods described above.

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

[0047] 1. The present invention provides a method for preparing a hob cutter ring, which comprises placing a "earth"-shaped preform made of a ceramic-metal composite material in a hob cutter ring mold, then pouring molten metal of high-hardness and wear-resistant steel into the hob cutter ring mold, so that the molten metal of high-hardness and wear-resistant steel fills the outer ring of the hob cutter ring mold, and at the same time infiltrates into the preform and wraps a portion of the preform; then pouring molten metal of high-toughness steel into the hob cutter ring mold, so that the molten metal of high-hardness and 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 portion 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 above ceramic composite material has the low expansion characteristics of ceramics, which can reduce the direct contact area of ​​the two alloys (i.e., high-hardness and wear-resistant steel and high-toughness steel) of the inner and outer rings (layers), and the two alloys are connected by the preform to form an expansion gradient between the three, thereby solving the problem of insufficient bonding strength of the composite materials due to different expansion coefficients during casting and cooling.

[0048] 2. Furthermore, the "earth"-shaped preform connects the inner layer of high-toughness steel and the outer layer of high-hardness wear-resistant steel, pinning the stress at the junction of the high-toughness steel and the high-hardness wear-resistant steel to avoid stress concentration. The upper head of the "earth"-shaped preform (i.e., the free end of the vertical column) is located in the high-hardness wear-resistant steel, which is beneficial for transferring the impact stress of the high-hardness wear-resistant steel to the inner layer of high-toughness steel during service. Specifically, after the stress of the high-hardness steel is formed, the stress will be transferred along the upper head of the "earth"-shaped preform to the horizontal line below, which can enable the inner layer of high-toughness steel to better absorb stress, thereby improving the fracture toughness of the knife ring.

[0049] 3. Furthermore, the present invention adopts a vertical centrifugal casting method, which has both centrifugal force and gravity during casting. Therefore, when the centrifuge rotates to the top, the molten metal flows faster and more fully into the preform under the action of gravity and centrifugal force, thereby improving the bonding strength between the molten metal and the preform. At the same time, the effect of gravity will also promote the improvement of the bonding strength between the inner and outer layers, further ensuring the degree of bonding 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 connecting structure between the inner ring and the outer ring. The connecting structure is in the shape of a "tu" character, and the material of the connecting structure is a ceramic-metal composite material; the upper part of the "tu" character of the connecting structure is located inside the outer ring, and the lower part 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 and wear-resistant steel; the connecting structure includes a preform in the shape of a "tu" character; 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; 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 high-toughness steel of the inner layer (inner ring) is beneficial to ensuring that the cutter ring has a 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 only exemplary, and for those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained according to 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 ⑶ and Example 1;

[0056] Figure 5 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Example ⑷ and Example 1;

[0057] Figure 6 Comparison chart of the compressive strength and impact toughness of the hob cutter rings prepared in Example ⑸ and Example 1;

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

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

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

[0061] Figure 10 Compressive strength and impact toughness comparison diagram of the hob 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 attached drawings required for use in the description of the implementation manners or the prior art will be briefly introduced below. The attached 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 attached drawings.

[0063] A preparation method of a hob 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 a "soil" character, 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 a "soil" character; 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, facilitates the separation and recombination between particles, and is beneficial 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. At the same time, it will hinder 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 ability to transmit 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 multiple preforms in a hob cutter ring mold, and then pouring high-hardness wear-resistant steel molten metal (first molten metal) into the hob cutter ring mold using a vertical centrifugal casting method, so that the high-hardness wear-resistant steel molten metal fills the outer ring of the hob cutter ring mold and simultaneously infiltrates into the preforms and partially envelops the preforms (i.e., a portion of the preforms is located in the first molten metal, preferably, the upper horizontal column of the "earth" shape and the vertical column above the upper horizontal column are located in the first molten metal);

[0069] Among them, the spacing angle between two adjacent preforms in the multiple preforms is 10~20 degrees; 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 wear-resistant steel 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;

[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 support effect of the preforms on the super-hard wear-resistant steel is reduced. 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 ultra-hard, wear-resistant steel molten metal solidifies to form an outer ring. After the temperature inside the outer ring cools to 1350-1400°C, high-toughness steel molten metal (second molten metal) is poured into the hob cutter ring mold using a vertical centrifugal casting method. The high-hard, wear-resistant steel molten metal fills the inner ring of the hob cutter ring mold and simultaneously infiltrates into the preform and wraps around another portion of the preform. The hob cutter ring is then heat treated and machined to obtain the hob cutter ring.

[0073] Among them, the inner side of the outer ring refers to the side of the ultra-hard wear-resistant steel liquid metal close to the center of the hob cutter ring. When cooled to 1350~1400℃, the high-hardness wear-resistant steel liquid metal 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 released first, which can effectively ensure its metallurgical bonding with the preform and the inner layer of high-toughness steel; when the temperature is higher than 1400℃, the outer layer metal is not completely solidified and cooled and shrunk, so when the inner layer of high-toughness steel is cast, it will solidify and shrink at the same time as the inner layer, and voids will be formed at the interface; when the temperature is lower than 1350℃, the shrinkage stress of the outer layer of ultra-hard wear-resistant steel is large, resulting in excessive bonding stress between the ultra-hard wear-resistant steel and ceramics, and insufficient bonding strength between the subsequently cast high-toughness steel and ceramics;

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

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

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

[0077] Furthermore, the "earth"-shaped preform connects the inner layer of high-toughness steel and the outer layer of high-hardness wear-resistant steel, pinning the stress at the junction of the high-toughness steel and the high-hardness wear-resistant steel to avoid stress concentration. The upper head of the "earth"-shaped preform (i.e., the free end of the vertical column) is located in the high-hardness wear-resistant steel, which is beneficial for transferring the impact stress of the high-hardness wear-resistant steel to the inner layer of high-toughness steel during service. Specifically, after the stress of the high-hardness steel is formed, the stress will be transferred along the upper head of the "earth"-shaped preform to the horizontal line below, which can enable the inner layer of high-toughness steel to better absorb stress, thereby improving the fracture toughness of the knife ring.

[0078] In another aspect, the present invention provides a hob cutter ring obtained by any of the above-mentioned preparation methods, the hob cutter ring comprising an inner ring, an outer ring, and a connecting structure between the inner ring and the outer ring, the connecting structure comprising a "earth"-shaped preform, the preform being made of a ceramic-metal composite material; the "earth"-shaped upper end of the preform being located within the outer ring, and the lower end being located within 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 portion of the preform is infiltrated and wrapped with the high-hardness wear-resistant steel, and another portion of the preform is infiltrated and wrapped with the high-toughness steel;

[0080] The microstructure of the inner ring includes ferrite and pearlite, with the volume fraction of ferrite being 30-40% and the volume fraction of pearlite being 60-70% by weight. The microstructure of the outer ring includes martensite, austenite, and carbides, and the carbides include VC and M7C3. 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 with a grain size of 100-150 nm.

[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 is further described below with reference to specific examples and comparative examples.

[0083] Example 1

[0084] This embodiment provides a method for preparing a hob cutter ring, the preparation process is as follows: Figure 1 As shown, the specific steps include:

[0085] Step 1) TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol are ball-milled and mixed, and the resulting ceramic slurry is centrifugally spray-dried to obtain a ceramic-metal composite powder; the ceramic-metal composite powder is mixed with a binder and loaded into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 6 mm and a length of approximately 4 cm;

[0086] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0087] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the 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 penetrates into the preform and partially wraps the preform; when pouring reaches 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; the high-hardness wear-resistant steel comprises, by mass percentage, 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 cools to 1380°C, pour molten metal of 20 steel (second molten metal) to allow the molten metal to penetrate into the preform and wrap the other part of the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring. The pouring temperature is 1530°C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / 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-milling WC ceramic powder, high-hardness wear-resistant steel powder, 42CrMo steel powder, and alcohol, and centrifugally spray-drying the resulting ceramic slurry to produce a ceramic-metal composite powder. The ceramic-metal composite powder is mixed with a binder and loaded into an automatic tablet press to produce a "earth"-shaped preform with a thickness of 6 mm and a length of approximately 5 cm.

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

[0095] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the cutter ring mold; and the spacing angle between two adjacent preforms is 10°;

[0096] 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 penetrates into the preform and partially wraps the preform; when pouring reaches the center line position of the cutter ring mold, stopping pouring;

[0097] The first molten metal is a molten metal of high-hardness wear-resistant steel; the high-hardness wear-resistant steel comprises, by mass percentage, 3.3 wt% C, 8.5 wt% V, 2.2 wt% Mo, 1.3 wt% Si, 0.4 wt% Mn, 2.1 wt% Ni, 0.2 wt% N, 2.5 wt% W, 0.75 wt% Al, 1.3 wt% Co, 0.8 wt% Nb, and the balance is Fe; the pouring temperature is 1530°C, the initial centrifugal speed is 550 rpm, and the final centrifugal speed is 1550 rpm.

[0098] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1400°C, pour 42CrMo steel molten metal (second molten metal) into the preform, allowing the molten metal to infiltrate the preform and partially wrap the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring; wherein, 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 of the hob cutter ring prepared in this embodiment is as follows: Figure 2 As shown, it can be seen that the outer layer of high hardness wear-resistant steel and 42CrMo are metallurgically bonded, and the interface structure is dense and defect-free; at the same time, the preform and the two high hardness wear-resistant steels and 42CrMo are also metallurgically bonded, and the bonding is good.

[0100] Comparative Example 1

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

[0102] Step 1) TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol are ball-milled and mixed, and the resulting ceramic slurry is centrifugally spray-dried to obtain a ceramic-metal composite powder; the ceramic-metal composite powder is mixed with a binder and loaded into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 6 mm and a length of approximately 4 cm;

[0103] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0104] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the cutter ring mold; and the spacing angle between two adjacent preforms is 15°;

[0105] The molten metal of high-hardness wear-resistant steel is obtained by smelting, and the molten metal of high-hardness wear-resistant steel is poured into the mold of the cutter ring by a vertical centrifugal casting method, so that the molten metal is infiltrated into the preform;

[0106] Among them, the high hardness and wear-resistant steel includes, in terms of mass percentage: 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.

[0107] The compressive strength and impact toughness of the hob cutter ring prepared in this comparative example and in Example 1 are compared. Figure 3 As shown, it can be seen that this comparative example is prepared by single-metal centrifugal casting. Due to the 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 knife ring of Example 1 of the present invention.

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

[0109] Example 3

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

[0111] Step 1) TiC ceramic powder, high-hardness wear-resistant steel powder, 20 steel powder, and alcohol are ball-milled and mixed, and the resulting ceramic slurry is centrifugally spray-dried to obtain a ceramic-metal composite powder; the ceramic-metal composite powder is mixed with a binder and loaded into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 6 mm and a length of approximately 4 cm;

[0112] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0113] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the cutter ring mold; and the spacing angle between two adjacent preforms is 15°;

[0114] Smelting to obtain a first molten metal, pouring the first molten metal into a cutter ring mold using a horizontal centrifugal casting method, so that the first molten metal penetrates into the preform and partially wraps the preform; when pouring reaches the center line position of the cutter ring mold, the pouring is stopped;

[0115] The first molten metal is a molten metal of high-hardness wear-resistant steel; the high-hardness wear-resistant steel comprises, by mass percentage, 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;

[0116] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1380°C, pour molten metal of 20 steel (second molten metal) to allow the molten metal to infiltrate the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring; wherein, 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 compressive strength and impact toughness of the hob cutter ring prepared in this embodiment and in Example 1 are compared. Figure 4 As shown, it can be seen that the present embodiment adopts a horizontal centrifugal casting process to prepare the cutter ring, and lacks the top gravity support effect of vertical centrifugal casting, resulting in poor bonding strength of the outer layer of the cutter ring and the metal and ceramic interface. Therefore, the compressive strength and impact toughness of this embodiment are lower than those of Example 1 of the present invention.

[0118] Example 4

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

[0120] 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;

[0121] The ceramic-metal composite powder and the binder were mixed and filled into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 3 mm and a length of about 4 cm.

[0122] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0123] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the 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 penetrates into the preform and partially wraps the preform; when pouring reaches 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; the high-hardness wear-resistant steel comprises, by mass percentage, 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 cools to 1380°C, pour molten metal of 20 steel (second molten metal) to allow the molten metal to infiltrate the preform and wrap the other part of the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring; wherein, the pouring temperature is 1530°C, the initial centrifugal speed is 550 r / min, and the final centrifugal speed is 1550 r / 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, some parts of the ceramic are burned more, 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] The ceramic-metal composite powder and the binder were mixed and filled into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 6 mm and a length of about 4 cm.

[0132] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0133] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the cutter ring mold; and the spacing angle between two adjacent preforms is 30 degrees;

[0134] 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 penetrates into the preform and partially wraps the preform; when pouring reaches the center line position of the cutter ring mold, stopping pouring;

[0135] The first molten metal is a molten metal of high-hardness wear-resistant steel; the high-hardness wear-resistant steel comprises, by mass percentage, 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;

[0136] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1380°C, pour molten metal of 20 steel (second molten metal) to allow the molten metal to infiltrate the preform and wrap the other part of the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring; wherein, 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 compressive strength and impact toughness of the hob cutter ring prepared in this embodiment and in Example 1 are compared. Figure 6As shown, it can be seen that the spacing angles between the preforms in this embodiment are large, so the number is small, 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, reducing the impact toughness of the knife ring.

[0138] Example 6

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

[0140] 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;

[0141] The ceramic-metal composite powder and the binder were mixed and filled into an automatic tablet press to prepare a "earth"-shaped preform with a thickness of 6 mm and a length of about 4 cm.

[0142] The high-hardness and wear-resistant steel powder comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the remainder being Fe. The mass ratio of the ceramic powder to the 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 the binder added is 15% of the total mass of the ceramic powder and the metal powder.

[0143] Step 2) placing multiple preforms in a cutter ring mold; wherein the free ends of the "earth"-shaped vertical columns of the multiple preforms are away from the center of the cutter ring mold and toward the outer ring of the cutter ring mold; the multiple preforms are evenly distributed along the circumference of the cutter ring mold; and the spacing angle between two adjacent preforms is 15°;

[0144] Smelting to obtain a first molten metal, pouring the first molten metal into a mold of a cutter ring using a vertical centrifugal casting method, so that the first molten metal infiltrates into the preform and partially wraps the preform; when pouring reaches the center line position of the cutter ring mold, stopping pouring;

[0145] The first molten metal is a molten metal of high-hardness wear-resistant steel; the high-hardness wear-resistant steel comprises, by mass percentage, 3wt% C, 7.5wt% V, 1.6wt% Mo, 1.2wt% Si, 0.3wt% Mn, 2wt% Ni, 0.2wt% N, 2.5wt% W, 0.6wt% Al, 1.4wt% Co, 0.8wt% Nb, and the balance is Fe; the pouring temperature is 1540°C, the initial centrifugal speed is 300 rpm, and the final centrifugal speed is 1450 rpm;

[0146] Step 3) When the inner surface temperature of the high-hardness wear-resistant steel cools to 1380°C, pour molten metal of 20 steel to allow the molten metal to infiltrate the preform until the cutter ring mold is fully filled. Then, heat treatment and machining are performed to obtain the hob cutter ring. The pouring temperature is 1530°C, the initial centrifugal speed is 550 rpm, and the final centrifugal speed is 1550 rpm.

[0147] The near-surface microstructure of the hob cutter ring prepared in this embodiment is compared with 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 cutter ring mold using 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 cools to 1380°C, pour molten metal of 20 steel (second molten metal) until the cutter ring mold is fully 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 550 r / min, and the final centrifugal speed is 1550 r / min.

[0153] Figure 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: Figure 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, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0155] The above description is merely 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 principles of the present invention shall be included within the scope of protection of the present invention. The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection 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 a "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 the 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; Among them, 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; multiple preforms are evenly distributed along the circumferential direction of the hob ring die; 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, 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; Among them, 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; Among them, the raw materials include ceramic powder, metal powder and a volatile solvent; among them, the volatile solvent is acetone or alcohol.

3. The method for preparing a hob cutter ring according to claim 2, characterized in that: The ceramic slurry is made into a ceramic-metal composite powder by centrifugal spray drying treatment.

4. The method for preparing a hob cutter ring according to claim 2, characterized in that: The pressing treatment is carried out in a tablet press; among them, the punch head of the tablet press is in the shape of a "soil"; the tablet press is an automatic tablet press.

5. 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; among them, the mass ratio of the high-toughness steel powder to the high-hardness wear-resistant steel powder is 1:1 to 1.5:1; the high-toughness steel powder is one or more of 20 steel, 42CrMo steel powder, 35CrMo steel powder, 4Cr5MoSiV steel powder, 40CrNiMo steel powder; the high-hardness wear-resistant steel powder is a steel powder with a hardness above HRC68.

6. 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.

7. The method for preparing a hob cutter ring according to claim 1, characterized in that: In the step 2): Among multiple preforms, the interval angle between adjacent two preforms is 10 to 20°.

8. 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 to 40 wt%; and / or In terms of 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.

9. 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.

10. The method for preparing a hob cutter ring according to claim 9, characterized in that: The pouring temperature of the first metal liquid is 1530 - 1550 °C; The initial centrifugal speed during vertical centrifugal casting is 500 - 600 r / min, and the final centrifugal speed is 1300 - 1600 r / min.

11. 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.

12. 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.

13. The method for preparing a hob cutter ring according to claim 12, characterized in that: The pouring temperature of the second metal liquid is 1500 - 1530 °C; The initial centrifugal speed during vertical centrifugal casting is 500 - 600 r / min, and the final centrifugal speed is 1300 - 1600 r / min.

14. A hob cutter ring, characterized in that: The hob 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 "tu", and the material of the connection structure is a ceramic metal composite material; the upper end of the "tu" shape of the connection structure is located inside the outer ring, and the lower end 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 wear-resistant steel; the hob ring is obtained by using the preparation method according to any one of claims 1 - 13.

15. The hob cutter ring according to claim 14, characterized in that: The connection structure includes a preform in the shape of "tu"; 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.

16. The hob cutter ring according to claim 14, wherein: 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%; 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 microstructure of the preform includes a polycrystalline structure, and the grain size of the polycrystalline structure is 100 - 150 nm.

17. The hob cutter ring according to any one of claims 14 to 16, characterized in that: 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 .

Images