A cemented carbide composite blade and a manufacturing process thereof

Abstract

The application discloses a cemented carbide composite blade and a preparation process, relates to the field of alloy blades, and comprises a base body, a center hole arranged in the middle part, and inwardly recessed inclined surfaces arranged on both sides, wherein the included angle between the inwardly recessed inclined surfaces and the vertical center line is 45-80 degrees; an outer ring part is arranged on the outer side of the base body, and the vertical section included angle between the outer ring part and the base body is 65-75 degrees; a curved groove surface is formed on the outer ring part; cemented carbide blades are fixedly installed on both sides of the outer ring part; the component materials of the cemented carbide blades are as follows: W: 64.2-78.6 wt%, C: 5.1-6.8 wt%, Fe: 0.5-1.5 wt%, Si: 0.1-0.3 wt%, Al: 0.3-0.8 wt%, Cr: 1.3-2.7 wt%, Ti: 2.4-4.0 wt%, Nb: 0.8-1.6 wt%, Co: 8-12 wt%, Mo: 0.5-1.0 wt%, Ta: 0.4-1.3 wt%, and the balance is Ni and trace residual impurities; REC=(Ta+Ti+Nb) / W+(Nb+Ti) / 2(Ni+Cr) is arranged, and 0.375<=REC<=0.705, so as to solve the technical problems that the alloy cannot be axially and radially reinforced on the cutter head, and the structural strength of the cemented carbide material is enhanced.

Description

Technical Field

[0001] This invention relates to the field of hardened cutting tool technology, specifically to a cemented carbide composite insert and its manufacturing process. Background Technology

[0002] Carbide materials are directly inlaid or welded to both sides of the cutting tool to form a composite cutting tool structure, which belongs to the category of carbide composite cutting tools. Carbide mostly contains tungsten, and has a series of excellent properties such as high hardness, wear resistance, good strength and toughness, heat resistance, and corrosion resistance. In particular, its high hardness and wear resistance remain basically unchanged even at a temperature of 500℃, and it still has a very high hardness at 1000℃.

[0003] Existing blade structures include CN201120162794.3 rolling shears, CN201710201032.1 a high-precision disc rolling shear blade and its manufacturing method, and CN202320680280.X a combined rolling shear blade.

[0004] The rotary shears, conforming to CN201120162794.3, feature an inclined surface on the blade body facing the center, secured by a pin. This inclined surface prevents the blade from detaching towards one axial direction, but is independent of its rotational shearing direction.

[0005] The high-precision disc roller shear blade and its manufacturing method are described in CN201710201032.1. The structure is a conventional circular shear blade with no structural limitations.

[0006] The present invention employs a combined rotary shearing tool, patented under CN202320680280.X, which utilizes an acute angle between the carbide cutting edge and the blade angle. This increases the force-bearing area of ​​the blade body during rotary shearing, ensuring the mechanical properties of the cutting edge. Actual cutting revealed that, in addition to radial pressure, the cutting position is also subjected to axial pressure at the point of contact with the material.

[0007] Existing cemented carbide materials use hard materials such as WC, high chromium, and high nickel, which combine high hardness, high strength, and high wear resistance. However, existing materials lack multi-component carbides to enhance the structure and system strength.

[0008] To address these issues, we provide a cemented carbide composite insert. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a cemented carbide composite insert to solve the technical problem that cemented carbide cannot be reinforced in both the axial and radial directions and to enhance the structural strength of cemented carbide materials.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] A cemented carbide composite insert, comprising:

[0012] The substrate has a central hole in the middle; the two ends of the substrate have recessed slopes with an angle of m between the recessed slopes and the vertical center line, where m ranges from 45° to 80°.

[0013] The outer ring is provided on the outside of the base. The angle between the outer ring and the vertical section of the base is n, where n ranges from 65° to 75°. A curved groove is provided on the outer ring. The thickness of the curved groove is less than the thickness of the outer ring. The center of the curved groove and the center of the outer ring are located on opposite sides of the edge of the outer ring.

[0014] Carbide cutting edge, with carbide cutting edges fixedly installed on both sides of the outer ring, and the two end corners of the carbide cutting edge are the cutting positions;

[0015] The components of the cemented carbide cutting edge, according to the mass percentage of each element, include:

[0016] W: 64.2–78.6 wt%, C: 5.1–6.8 wt%, Fe: 0.5–1.5 wt%, Si: 0.1–0.3 wt%, Al: 0.3–0.8 wt%, Cr: 1.3–2.7 wt%, Ti: 2.4–4.0 wt%, Nb: 0.8–1.6 wt%, Co: 8–12 wt%, Mo: 0.5–1.0 wt%, Ta: 0.4–1.3 wt%, with the balance being Ni and trace residual impurities;

[0017] Where REC is set to (Ta+Ti+Nb) / W+(Nb+Ti) / 2(Ni+Cr), and 0.375≤REC≤0.705.

[0018] The alloy substrate of this application is a tungsten alloy, with WC accounting for 70-85%, the main hard phase, providing ultra-high hardness and wear resistance; Co accounting for 8-12%, a metallic binder phase, which can improve toughness and impact resistance; TiC accounting for 3-5%, a secondary hard phase, enhancing red hardness; Cr3C2 accounting for 2-4%, which refines grains and improves oxidation and corrosion resistance; NbC accounting for 1-2%, which inhibits grain growth and improves high-temperature strength; TaC accounting for 0.5-1.5%, which improves thermal stability. Mo2C enhances resistance to crater wear. The advantage of this invention is that the alloy formation incorporates a Cr3C2 / NbC synergistic inhibitor, increasing the WC grain growth activation energy to 450 kJ / mol. Furthermore, magnetic field-assisted sintering is used to allow the Co phase to grow along the grain... <001> Preferred orientation is selected; then, an in-situ reaction generates a (W,Ti,Ta)C solid solution shell structure, enhancing interfacial bonding strength. Secondly, this invention limits the ratio of (Ta+Ti+Nb) / W to increase the total proportion of (Ti+Ta+Nb). A higher proportion improves red hardness, making it suitable for high-speed cutting metal inserts, while a lower proportion results in larger grains. Nb can form a stable γ' strengthening phase, and the segregation of Nb in the alloy affects the microstructure differences within the grains. Furthermore, the refining ability of Nb and Ti depends on their proportions and needs to be controlled to avoid cracks and precipitate morphologies. The addition of Nb leads to the formation of a nanoscale carbide second phase within the coating, significantly reducing its overheat sensitivity, refining the grain size, and forming various metallic compound phases, such as NbCo2 and NbCo5. During alloy solidification, these compound phases act as nucleation sites for heterogeneous formation, promoting grain nucleation and growth, resulting in fine grains. During alloy preparation, titanium readily absorbs oxygen and hydrogen, forming an oxide layer. Grains in high-temperature alloys tend to grow rapidly at high temperatures, leading to unstable grain boundaries, porosity, and crack formation, thus reducing the material's mechanical properties. The addition of titanium can combine with impurities at grain boundaries to form stable compounds, thereby inhibiting grain growth and stabilizing the grain boundary structure. Setting (Nb+Ti) / 2(Ni+Cr) aims to minimize grain size while maintaining red hardness, but also needs to balance this to prevent nonlinear changes caused by excessively small grains, which could reduce strength.

[0019] In a further technical solution, a heat dissipation structure is provided on the substrate. The heat dissipation structure includes vertical air channels and horizontal air channels, and the vertical air channels and horizontal air channels are connected to each other. The two ends of the horizontal air channels are connected to both sides of the substrate.

[0020] In a further technical solution, a connecting structure is provided between the outer ring and the cemented carbide cutting edge;

[0021] The connecting structure includes a protrusion and a recess, with the recess located on both sides of the outer ring portion; the protrusion is located on the side of the carbide cutting edge facing the outer ring portion, and the protrusion and the recess are compatible.

[0022] In a further technical solution, the edge line of the cemented carbide cutting edge away from the central hole is flush with the edge line of the corresponding outer ring portion away from the central hole.

[0023] In a further technical solution, the lateral vertical cross-section of the outer ring is trapezoidal outside the substrate, and the waist length distance gradually decreases away from the central hole.

[0024] In a further technical solution, the cemented carbide cutting edge includes a first connecting part, a second connecting part, and an intermediate ring; the second connecting part and the first connecting part are located on both sides of the outer ring and are fixedly connected to each other by the intermediate ring.

[0025] In a further technical solution, the cemented carbide cutting edge has a positioning hole on the side facing the substrate, and the positioning hole is a threaded hole;

[0026] The base includes a retaining ring and a groove. One end of the groove extends to the center hole and the other end extends to the retaining ring. A positioning bolt is installed on the retaining ring. The bolt body passes through the retaining ring to the positioning hole of the carbide cutting edge. The positioning bolt and the positioning hole are threaded together.

[0027] In a further technical solution, inclined air passages are provided on both sides of the vertical air passage away from the central hole, and the inclined air passages are connected to the notch.

[0028] A manufacturing process for a cemented carbide composite cutting tool, characterized in that:

[0029] Carbide blade treatment:

[0030] A. Powder Pretreatment

[0031] Step a1, Preparation of nanocomposite powder: Existing alloy materials WC, Co, and TiC were ground to 0.8 μm, 1.2 μm, and 200 nm respectively using a plasma ball milling device; the powders were mixed in an Ar atmosphere for 24 h at a speed of 500 rpm and a ball-to-powder ratio of 10:1.

[0032] Step a2, Surface modification: Add 0.1% zinc stearate as a dispersant, and coat the WC surface with a 2nm thick Cr coating by chemical vapor deposition;

[0033] B. Molding process

[0034] Step b1, cold isostatic pressing: Under pressure of 200MPa, hold pressure for 5 minutes to obtain a green compact density ≥60% of the theoretical density;

[0035] Step b2, 3D gradient structure design: Achieving a WC content gradient in the cutting edge region through multi-layer powder spreading technology;

[0036] C. Sintering process: Two-step sintering method:

[0037] Step c1, Degreasing stage: Under H2 atmosphere, 600℃×2h, heating rate 3℃ / min;

[0038] Step c2, liquid phase sintering: under vacuum conditions, from 1450℃ for 1 hour, then the temperature is increased to 1500℃ for 0.5 hours; to achieve full densification, the relative density is measured to be ≥99.9%;

[0039] High-pressure gas quenching: After quenching in N2 gas to 800℃, the mixture is transferred to oil cooling to obtain a nanotwinned structure;

[0040] D. Post-processing

[0041] Step d1, cryogenic treatment: Treat with liquid nitrogen at -196℃ for 24 hours to eliminate residual austenite;

[0042] Step d2, PVD coating: Deposit a 2μm thick AlTiN / Si3N4 multilayer nanocoating;

[0043] Matrix processing:

[0044] High-strength steel 42CrMo4 is selected, laser roughened, and cut to form the outer ring.

[0045] Vacuum brazing:

[0046] Solder selection: BAg-8Ti solder is used, with a melting point of 780-820℃, a foil thickness of 0.1mm, and a Ti content of 4wt%, to promote the WC / steel interfacial reaction; Process parameters: Vacuum degree ≤5×10 -3 Pa, temperature: 750-850℃, gradient slow cooling for 10-30 min.

[0047] Compared with existing technologies, it has the following advantages:

[0048] This invention employs vertical and horizontal air channels on the carbide composite cutting tool to reduce heat concentration on the cutting disc and decrease the tool's mass during cutting. A trapezoidal outer ring is formed on the surface. The area subjected to prolonged grinding is the outer apex of the carbide cutting edge; the trapezoidal shape results in a longer carbide cutting edge on the central surface, leading to a larger allowance for lateral wear during grinding, which is beneficial for long-term shearing use.

[0049] The advantage of this invention lies in the inclusion of a Cr3C2 / NbC synergistic inhibitor in the alloy formation, which increases the activation energy for WC grain growth to 450 kJ / mol. Secondly, magnetic field-assisted sintering is employed to allow the Co phase to grow along the grain. <001> The orientation is preferentially selected; then, an in-situ reaction is used to generate a (W,Ti,Ta)C solid solution shell structure to improve the interfacial bonding strength. Secondly, this invention limits (Ta+Ti+Nb) / W to increase the total proportion of (Ti+Ta+Nb). A higher proportion improves red hardness, making it suitable for metal cutting tools used in high-speed cutting. Setting (Nb+Ti) / 2(Ni+Cr) minimizes grain size while ensuring red hardness, but it is also necessary to balance this to prevent nonlinear changes caused by excessively small grains, which could reduce strength.

[0050] The present invention features a protrusion and a recess; the connecting structure also enhances radial support and ensures the cutting strength of the carbide blade.

[0051] The present invention features an oblique air passage that connects the carbide blade with the vertical and horizontal air passages, thereby achieving a more convenient heat dissipation effect. Attached Figure Description

[0052] Figure 1 This is a front view of the cemented carbide composite cutting tool according to Embodiment 1 of the present invention;

[0053] Figure 2 for Figure 1 AA section view;

[0054] Figure 3 for Figure 2 Enlarged schematic diagram of part B;

[0055] Figure 4 This is a front view of the substrate and outer ring portion of Embodiment 1 of the present invention (excluding the cemented carbide blade);

[0056] Figure 5 This is a front view of the cemented carbide composite cutting tool of Embodiment 2 of the present invention.

[0057] Figure 6 for Figure 5 CC cross-sectional view;

[0058] Figure 7 This is a schematic diagram of the base and outer ring structure of Embodiment 3 of the present invention (excluding the cemented carbide cutting edge);

[0059] Figure 8 This is a vertical sectional view of the cemented carbide composite insert of Embodiment 3 of the present invention;

[0060] Figure 9 for Figure 8 Enlarged view of part D;

[0061] Figure 10 This is a front view of the cemented carbide composite cutting tool of Embodiment 4 of the present invention;

[0062] Figure 11 This is a vertical sectional view of the cemented carbide composite insert of Embodiment 4 of the present invention;

[0063] Figure 12 for Figure 11 Enlarged view of part E;

[0064] Figure 13 This is a vertical sectional view of the cemented carbide composite insert of Embodiment 5 of the present invention;

[0065] Figure 14 for Figure 13 Enlarged view of part E.

[0066] In the picture:

[0067] 1. Matrix; 2. Outer ring; 3. Carbide blade; 4. Vertical air passage; 5. Horizontal air passage; 7. Positioning bolt; 8. Angled air passage;

[0068] 11. Fixing ring; 12. Groove; 13. Center hole; 14. Inward bevel;

[0069] 21. Notch 1; 22. Curved groove surface;

[0070] 31. Protrusion 1; 32. Connecting part 1; 33. Connecting part 2; 34. Intermediate ring; 35. Positioning hole. Detailed Implementation

[0071] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0072] Example 1

[0073] Please see Figure 1-5 This invention provides a technical solution.

[0074] A cemented carbide composite insert, comprising:

[0075] The substrate 1 has a central hole 13 in the middle; the two ends of the substrate 1 have recessed inclined surfaces 14, the angle between the recessed inclined surface 14 and the vertical center line is m, and the range of m is 45 to 80°.

[0076] The outer ring 2 is provided on the outside of the base 1. The angle between the outer ring 2 and the vertical section of the base 1 is n, where n ranges from 65° to 75°. A curved groove surface 22 is provided on the outer ring 2. The thickness of the curved groove surface 22 is less than the thickness of the outer ring 2. The center of the curved groove surface 22 and the center of the outer ring 2 are located on opposite sides of the edge of the outer ring 2.

[0077] Carbide cutting edges 3 are fixedly installed on both sides of the outer ring 2, with the two end corners of the carbide cutting edges serving as cutting positions. Two sets of included angles m and n are set to ensure that the connection position is in an inclined state and that radial and axial cutting support forces exist to guarantee the cutting effect. A curved groove surface is provided to ensure that the brazed carbide material has an adhesion and support effect, achieving a stable brazed connection.

[0078] The components of the cemented carbide blade 3, according to the mass percentage of each element, include:

[0079] W: 64.2–78.6 wt%, C: 5.1–6.8 wt%, Fe: 0.5–1.5 wt%, Si: 0.1–0.3 wt%, Al: 0.3–0.8 wt%, Cr: 1.3–2.7 wt%, Ti: 2.4–4.0 wt%, Nb: 0.8–1.6 wt%, Co: 8–12 wt%, Mo: 0.5–1.0 wt%, Ta: 0.4–1.3 wt%, with the balance being Ni and trace residual impurities;

[0080] Where REC is set to Ta + Ti + Nb / W + Nb + Ti / 2Ni + Cr, and 0.375 ≤ REC ≤ 0.705.

[0081] The synergistic enhancement of multi-component complex carbides is specifically manifested in the following ways:

[0082]

[0083] Example 2

[0084] like Figure 5 and 6 As shown, another embodiment of the present invention is provided on the basis of embodiment 1. A heat dissipation structure is provided on the substrate 1. The heat dissipation structure includes a vertical air channel 4 and a horizontal air channel 5, and the vertical air channel 4 and the horizontal air channel 5 are connected to each other. The two ends of the horizontal air channel 5 are connected to the two sides of the substrate 1.

[0085] In this embodiment, vertical and horizontal air channels are provided on the carbide composite cutting tool to reduce heat concentration on the cutting disc and reduce the weight of the cutting tool during cutting. A trapezoidal outer ring is provided on the surface. The area that is subjected to long-term grinding is the outer apex of the carbide cutting edge. The trapezoidal shape makes the carbide cutting edge on the middle surface longer, resulting in a larger allowance for lateral wear during grinding, which is beneficial for long-term shearing use.

[0086] Example 3

[0087] like Figure 7-9 As shown, another embodiment of the present invention is provided, based on embodiment 2, with a connecting structure provided between the outer ring 2 and the carbide blade 3;

[0088] The connecting structure includes a protrusion 31 and a recess 21, with the recess 21 located on both sides of the outer ring portion 2; the protrusion 31 is located on the side of the carbide blade 3 facing the outer ring portion 2, and the protrusion 31 and the recess 21 are compatible.

[0089] The edge of the carbide cutting edge 3 away from the central hole 13 is flush with the edge of the corresponding outer ring portion 2 away from the central hole 13. This flush surface facilitates cutting and does not interfere with material movement. The lateral vertical cross-section of the outer ring portion 2 is trapezoidal outside the base 1, and the waist-length spacing gradually decreases towards the distance from the central hole 13. The carbide cutting edge 3 includes a first connecting portion 32, a second connecting portion 33, and an intermediate ring 34; the ends of the second connecting portion 33 and the first connecting portion 32 are located on opposite sides of the outer ring portion 2 and are fixedly connected by the intermediate ring 34.

[0090] In this embodiment, the cemented carbide blade is machined into a single piece to ensure the integrity of the connection. During manufacturing, the notch and protrusion are connected by high-temperature brazing.

[0091] Example 4

[0092] like Figure 10-12 As shown, another embodiment of the present invention is provided. Based on embodiment 3, the carbide blade 3 is provided with a positioning hole 35 on the side facing the base 1. The positioning hole 35 is a threaded hole.

[0093] The base 1 includes a fixing ring 11 and a groove 12. The groove is formed by boring a pin into the base. A positioning bolt is installed in the groove, and the head of the positioning bolt is fitted with a bonding plate that fits onto the fixing ring to achieve a tight connection. One end of the groove 12 extends to the central hole 13, and the other end extends to the fixing ring 11. A positioning bolt 7 is installed on the fixing ring 11. The bolt body of the positioning bolt 7 passes through the fixing ring 11 to the positioning hole 35 of the carbide cutting edge 3, and the positioning bolt 7 and the positioning hole 35 are threaded together.

[0094] Example 5

[0095] like Figure 13 and 14 As shown, another embodiment of the present invention is provided. Based on embodiment 4, inclined air channels 8 are provided on both sides of the vertical air channel 4 away from the central hole 13, and the inclined air channels 8 are connected to the notch 21. The inclined air channels connect the carbide blade with the vertical air channel and the horizontal air channel, thereby achieving a more convenient heat dissipation effect.

[0096] A manufacturing process for a cemented carbide composite cutting tool, characterized in that:

[0097] Carbide blade 3 treatment:

[0098] A. Powder Pretreatment

[0099] Step a1, Preparation of nanocomposite powder: Existing alloy materials WC, Co, and TiC were ground to 0.8 μm, 1.2 μm, and 200 nm respectively using a plasma ball milling device; the powders were mixed in an Ar atmosphere for 24 h at a speed of 500 rpm and a ball-to-powder ratio of 10:1.

[0100] Step a2, Surface modification: Add 0.1% zinc stearate as a dispersant, and coat the WC surface with a 2nm thick Cr coating by chemical vapor deposition;

[0101] B. Molding process

[0102] Step b1, cold isostatic pressing: Under pressure of 200MPa, hold pressure for 5 minutes to obtain a green compact density ≥60% of the theoretical density;

[0103] Step b2, 3D gradient structure design: Achieving a WC content gradient in the cutting edge region through multi-layer powder spreading technology;

[0104] C. Sintering process: Two-step sintering method:

[0105] Step c1, Degreasing stage: Under H2 atmosphere, 600℃×2h, heating rate 3℃ / min;

[0106] Step c2, liquid phase sintering: under vacuum conditions, from 1450℃ for 1 hour, then the temperature is increased to 1500℃ for 0.5 hours; to achieve full densification, the relative density is measured to be ≥99.9%;

[0107] High-pressure gas quenching: After quenching in N2 gas to 800℃, the mixture is transferred to oil cooling to obtain a nanotwinned structure;

[0108] D. Post-processing

[0109] Step d1, cryogenic treatment: Treat with liquid nitrogen at -196℃ for 24 hours to eliminate residual austenite;

[0110] Step d2, PVD coating: Deposit a 2μm thick AlTiN / Si3N4 multilayer nanocoating;

[0111] Matrix 1 processing:

[0112] High-strength steel 42CrMo4 was selected, laser roughened, and cut to form the outer ring 2;

[0113] Vacuum brazing:

[0114] Solder selection: BAg-8Ti solder is used, with a melting point of 780-820℃, a foil thickness of 0.1mm, and a Ti content of 4wt%, to promote the WC / steel interfacial reaction; Process parameters: Vacuum degree ≤5×10 -3 Pa, temperature: 750-850℃, gradient slow cooling for 10-30min.

[0115] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A cemented carbide composite insert, characterized in that, The utility model relates to a cutting tool, including: a base (1) provided with a central hole (13) in the middle of the base (1); the two ends of the base (1) are provided with inwardly recessed inclined surfaces (14) with an angle m of 45-80 degrees with the vertical center line; an outer ring part (2) provided on the outer side of the base (1) with an angle n of 65-75 degrees with the vertical section of the base (1); the outer ring part (2) is provided with a curved groove surface (22); the thickness of the curved groove surface (22) is less than that of the outer ring part (2); the centers of the curved groove surface (22) and the outer ring part (2) are located on the two sides of the outer ring part (2) side line; a hard alloy blade (3) fixedly installed on the two sides of the outer ring part (2), with the two side end angles of the hard alloy blade being the cutting positions; the component materials of the hard alloy blade (3) include, by mass fraction: W: 64.2-78.6wt%, C: 5.1-6.8wt%, Fe: 0.5-1.5wt%, Si: 0.1-0.3wt%, Al: 0.3-0.8wt%, Cr: 1.3-2.7wt%, Ti: 2.4-4.0wt%, Nb: 0.8-1.6wt%, Co: 8-12wt%, Mo: 0.5-1.0wt%, Ta: 0.4-1.3wt%, and the balance is Ni and trace residual impurities; wherein, REC = (Ta+Ti+Nb) / W+ (Nb+Ti) / 2(Ni+Cr) is set, and 0.375<=REC<=0.705; a connecting structure is arranged between the outer ring part (2) and the hard alloy blade (3); the connecting structure includes a protrusion one (31) and a notch one (21), and the notch one (21) is arranged on the two sides of the outer ring part (2); the protrusion one (31) is arranged on the side of the hard alloy blade (3) facing the outer ring part (2), and the protrusion one (31) and the notch one (21) are matched; the side line of the hard alloy blade (3) away from the central hole (13) is flush with the side line of the corresponding outer ring part (2) away from the central hole (13); the lateral vertical section of the outer ring part (2) is trapezoidal outside the base (1), and the waist length interval gradually decreases away from the central hole (13); the hard alloy blade (3) includes a connecting part one (32), a connecting part two (33) and an intermediate ring (34); the connecting part two (33) and the connecting part one (32) are respectively located on the two sides of the outer ring part (2) and are fixedly connected through the intermediate ring (34).

2. A cemented carbide composite insert according to claim 1, characterized in that a heat dissipation structure is arranged on the base (1), and the heat dissipation structure includes a vertical air duct (4) and a horizontal air duct (5), and the vertical air duct (4) and the horizontal air duct (5) are communicated; 3. A cemented carbide composite insert according to claim 2, characterized in that a positioning hole (35) is arranged on the side of the hard alloy blade (3) facing the base (1), and the positioning hole (35) is a threaded hole; The base (1) comprises a fixed ring part (11) and a pull slot (12), one end of the pull slot (12) extends to the center hole (13), the other end extends to the fixed ring part (11), a positioning bolt (7) is installed on the fixed ring part (11), the shank of the positioning bolt (7) passes through the fixed ring part (11) to the positioning hole (35) of the hard alloy blade (3), and the positioning bolt (7) and the positioning hole (35) are threadedly connected.

4. A cemented carbide composite cutting tip according to claim 3, characterized in that The vertical air duct (4) is provided with an inclined air duct (8) away from the two sides of the center hole (13) upward, and the inclined air duct (8) is communicated with the notch (21).

5. The preparation process of the cemented carbide composite blade according to claim 4, characterized in that: The hard alloy blade (3) is processed: A. Powder pretreatment Step a1, nano-composite powder preparation: using plasma ball milling equipment, existing alloy materials WC, Co and TiC are ground to 0.8μm, 1.2μm and 200nm respectively; the powders are mixed in Ar atmosphere for 24h, the rotation speed is 500rpm, and the ball-to-material ratio is 10:1; Step a2, surface modification: adding 0.1% zinc stearate as a dispersant, coating a 2nm thick Cr coating on the surface of WC by chemical vapor deposition; B. Forming process Step b1, cold isostatic pressing: under the condition of 200MPa pressure, pressure maintaining for 5min, the green density is ≥60% of the theoretical density; Step b2, 3D gradient structure design: WC content gradient in the blade edge area is realized through multi-layer powder laying technology; C. Sintering process: two-step sintering method: Step c1, debinding stage: in H2 atmosphere, 600℃×2h, heating rate 3℃ / min; Step c2, liquid phase sintering: under vacuum environment, from 1450℃, 1h, then heating to 1500℃, 0.5h; full densification is achieved, and the relative density is ≥99.9%; High-pressure gas quenching: after N2 gas quenching to 800℃, oil cooling is carried out, and a nano-twin structure is obtained; D. Post-processing Step d1, cryogenic treatment: -196℃ liquid nitrogen treatment for 24h to eliminate residual austenite; Step d2, PVD coating: depositing a 2μm thick AlTiN / Si3N4 multilayer nano coating; Base (1) processing: Select high-strength steel 42CrMo4, laser roughening, and cut to form an outer ring part (2); Vacuum brazing: Selection of brazing filler metal: BAg-8Ti brazing filler metal is selected, the melting point is 780-820℃, and the thickness is: 0.1 mm foil, Ti content 4 wt%, to promote the interface reaction of WC / steel; process parameters: vacuum degree ≤ 5 x 10 -3 Pa, temperature: gradient slow cooling at 750-850 °C for 10-30 min.

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