High-strength and high-toughness cutter composite board and preparation method thereof

Abstract

The invention discloses a high-strength and high-toughness cutter composite board which comprises a base material and a covering material, the base material comprises the following chemical components in percentage by mass: 0.04 to 0.10 percent of C, 0.35 to 0.55 percent of Si, 1.2 to 1.6 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.002 percent of S, 0.02 to 0.05 percent of Nb, 0.01 to 0.03 percent of V, 0.015 to 0.025 percent of Ti, 0.5 to 1.0 percent of Ni, 0.6 to 0.8 percent of Cr, 0.05 to 0.15 percent of Mo, 0.03 to 0.06 percent of Als and the balance of Fe and inevitable impurity elements; the covering material comprises the following chemical components in percentage by mass: 0.7-0.9% of C, less than or equal to 1.0% of Si, less than or equal to 1.0% of Mn, less than or equal to 0.03% of P, less than or equal to 0.02% of S, 12-16% of Cr, 0.1-0.3% of Mo, 0.1-0.2% of V and 0.1-0.3% of Ni; and the balance of Fe and inevitable impurity elements. The cutter composite board has high strength, high toughness, high hardness, high wear resistance and high corrosion resistance, the contradiction that a traditional single-material cutter is hard to be crisp and tough to be soft is solved, and the cutter composite board which is high in performance, long in service life and easy to maintain is obtained.

Description

Technical Field

[0001] This invention relates to a high-strength and high-toughness tool composite plate and its preparation method. Background Technology

[0002] In the high-end knife manufacturing field, professional kitchen knives, outdoor knives, and industrial cutting tools place stringent demands on the comprehensive performance of materials. However, a single material system often struggles to achieve a balance between high strength, high toughness, excellent wear resistance, and good corrosion resistance. While traditional high-carbon steel possesses high hardness and excellent sharpness, its toughness is poor and it is prone to corrosion; while conventional stainless steel performs well in terms of corrosion resistance, its hardness and wear resistance are insufficient to meet the application requirements of high-end knives. Although some high-end powder metallurgy steels (such as CPM-S30V and ZDP-189) can achieve a better balance of hardness, toughness, and corrosion resistance, their raw material and manufacturing costs are extremely high, limiting their application in a wider market.

[0003] With the continuous development of production technology, composite material technology has emerged to overcome the performance bottlenecks of single materials. Composite materials can achieve "performance combinations" and "functional designs" that are difficult to achieve with single materials in an economical and efficient way. Therefore, tool steel can also be made by combining a "matrix" material that provides strength and toughness with a "blade material" material that provides high hardness and wear resistance through solid-state metallurgical bonding. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a high-strength and high-toughness tool composite plate and its preparation method. It has high strength, high toughness, high hardness, high wear resistance and corrosion resistance, and solves the contradiction of traditional single material tools being "hard but brittle, tough but soft". It obtains a high-performance, long-life and easy-to-maintain tool composite plate.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows: A high-strength and high-toughness tool composite plate includes a substrate and a cladding material. The chemical composition and mass percentage of the substrate are as follows: C: 0.04-0.10%, Si: 0.35-0.55%, Mn: 1.2-1.6%, P≤0.015%, S≤0.002%, Nb: 0.02-0.05%, V: 0.01-0.03%, Ti: 0.015-0.025%, Ni: 0.5-1.0%, Cr: 0.6-0.8%, Mo: 0.05-0.15%, Als: 0.03-0.06%, with the remainder being Fe and unavoidable impurity elements. The chemical composition and mass percentage of the coating material are as follows: C: 0.7-0.9%, Si≤1.0%, Mn≤1.0%, P≤0.03%, S≤0.02%, Cr: 12-16%, Mo: 0.1-0.3%, V: 0.1-0.2%, Ni: 0.1-0.3%; the remainder is Fe and unavoidable impurity elements.

[0006] The composite board described above has a yield strength ≥450 MPa, tensile strength ≥550 MPa, elongation ≥21%, impact energy at -40℃ ≥160 J, shear strength ≥280 MPa, and surface hardness of the coating ≥52 HRC.

[0007] This invention provides a method for preparing a high-strength and high-toughness tool composite plate, characterized by the following steps: S1 billet preparation: Based on the composition of the base material, the billet is obtained by sequentially smelting in a converter, refining in an LF furnace, treating with RH, continuous casting, and billet making; based on the composition of the cladding material, the billet is obtained by sequentially smelting in an induction furnace, refining in an LF furnace, vacuum casting in a VOD furnace, die casting, and forging. S2 billet assembly: Stack carbon steel-cladding material-substrate-cladding material-carbon steel in the following order. Grind the substrate and cladding material surfaces to be joined until they are exposed to a metallic luster. Apply release agent to the contact surface between the cladding material and carbon steel and dry it. Use gas shielded welding to fix the cladding material to the substrate and carbon steel around the perimeter by spot welding at intervals. Then seal the perimeter of the cladding material with carbon steel sealing strips and weld the seal by submerged arc welding. Finally, vacuum the composite billet. S3 heating: Heat the composite billet to 1220~1280℃, and control the total heating time according to the thickness of the composite billet at 14~20min / cm. The tapping temperature is 1190~1250℃. S4 controlled rolling and cooling: The first two passes use symmetrical angle rolling with a reduction rate of 10-18%; subsequent low-speed high-reduction rolling with a reduction rate of ≥18% and the intermediate billet thickness is 1.8-2.6 times the rolling thickness; the finishing rolling start temperature is ≤890℃ and the finishing rolling temperature is 820-860℃; after rolling, online quenching is performed, followed by offline stacking cooling. S5 tempering heat treatment: Temper at 180~350℃, with tempering time controlled at 1.8~2.8min / mm based on the total thickness of the composite board, followed by air cooling to room temperature; S6 plate straightening: The head, tail and uncoated areas on both sides of the composite plate are cut off, the upper and lower carbon steel plates and the coating are separated, the plate shape is straightened, and the coating surface is polished and sealed to obtain a double-sided high-strength and high-toughness tool composite plate.

[0008] Preferably, in step S2, the carbon steel used is a billet with a thickness of 64 mm, and the composite billet obtained after assembly has a thickness of 304-352 mm.

[0009] Preferably, in step S3, the composite billet is heated in stages: first, the temperature is raised to 800-900°C at a rate of 10-15°C / min, held for 30-60 min, and then raised to 1220-1280°C at a rate of 5-8°C / min.

[0010] Preferably, in step S4, the rolling process is followed by online quenching, with a red-heat temperature of 350–450°C.

[0011] Preferably, in step S2, a release agent is applied to the contact surface between the covering material and the carbon steel and then dried. The release agent is an Al2O3-based release agent, and the material is dried at a temperature of 80–120°C for 15–30 minutes.

[0012] The beneficial effects of this invention are: This invention organically combines the high strength, high toughness, and excellent weldability of low alloy high-strength steel with the high hardness, high wear resistance, and corrosion resistance of martensitic stainless steel through reasonable alloy composition design and production process. This achieves a metallurgical bond between the substrate and the cladding material, resulting in high interfacial bonding strength and a dense and uniform internal structure, thus ensuring a long service life for the product.

[0013] This invention solves the problem of difficult welding of high-carbon martensitic stainless steel cladding in double-sided rolled composite plates through a special billet design, effectively avoiding weld cracking during the rolling process.

[0014] This invention uses a process of fixing the cladding layer by intermittent spot welding and symmetrical angle rolling to ensure that the cladding material and the substrate are preferentially bonded diagonally. This improves the synchronous deformation of the cladding material and the substrate and avoids the problem of uneven thickness of the cladding layer at the beginning, end and edges due to the large difference in deformation resistance between the cladding material and the substrate. This improves the yield.

[0015] This invention yields a high-strength and high-toughness composite plate for cutting tools, with a yield strength ≥450 MPa, tensile strength ≥550 MPa, elongation ≥21%, impact energy at -40℃ ≥160 J, shear strength ≥280 MPa, and surface hardness of the coating ≥52 HRC.

[0016] This invention significantly reduces material costs while ensuring performance, achieving extremely high cost-effectiveness. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the billet assembly structure of the present invention; 1: Base material; 2: Covering material; 3: Seal; 4: Submerged arc weld; 5: Gas shielded weld; 6: Carbon steel. Detailed Implementation

[0018] To make the content of this invention easier to understand, the invention will be further described in detail below based on specific embodiments. Example

[0019] This embodiment provides a high-strength and high-toughness tool composite plate, comprising a substrate and a cladding material. The chemical composition and mass percentage of the substrate are as follows: C: 0.06%, Si: 0.46%, Mn: 1.37%, P: 0.012%, S: 0.0015%, Nb: 0.028%, V: 0.013%, Ti: 0.018%, Ni: 0.77%, Cr: 0.68%, Mo: 0.013%, Als: 0.034%, with the remainder being Fe and unavoidable impurity elements. The chemical composition and mass percentage of the cladding material are as follows: C: 0.86%, Si: 0.59%, Mn: 0.54%, P: 0.028%, S: 0.008%, Cr: 15.34%, Mo: 0.26%, V: 0.13%, Ni: 0.15%; the remainder is Fe and unavoidable impurity elements.

[0020] This embodiment also provides a method for preparing a high-strength and high-toughness tool composite plate, which mainly includes the following steps: (1) Billet preparation: Based on the composition of the base material, the base material billet is obtained by converter smelting, LF refining, RH treatment, continuous casting and billet making with a thickness of 144mm; based on the composition of the cladding material, the cladding material billet is obtained by induction furnace melting, LF refining, VOD vacuum, die casting and forging with a thickness of 16mm. For carbon steel, a billet with a thickness of 64mm is selected. (2) Assembly: such as Figure 1 As shown, carbon steel 6-cladding material 2-substrate 1-cladding material 2-carbon steel 6 are stacked in sequence. The surfaces of the substrate and cladding material to be bonded need to be ground smooth to expose the metallic luster. The contact surface between the cladding material and the carbon steel is coated with an Al2O3-based release agent and dried at 100℃ for 20 minutes. Gas shielded welding is used to fix the cladding material to the substrate and the carbon steel around the perimeter to form gas shielded weld seam 5. Then, carbon steel sealing strip 3 is used to seal the perimeter of the cladding layer, and then submerged arc welding is used to seal the perimeter to form submerged arc weld seam 4. The composite billet is then vacuumed to obtain a 304mm thick composite billet. (3) Heating: The composite billet is heated in stages. First, the temperature is raised to 800℃ at a rate of 10℃ / min and held for 45min. Then, the temperature is raised to 1250℃ at a rate of 6℃ / min. The total heating time is 458min and the tapping temperature is 1213℃. (4) Controlled rolling and controlled cooling: The first two passes are rolled using symmetrical angle rolling, with the reduction rate controlled at 11-15%. Subsequent passes are rolled using low speed and high reduction, with a reduction rate ≥22% and an intermediate billet thickness of 82mm. The finishing rolling start temperature is 875℃ and the finishing rolling temperature is 837℃. After rolling, the billet is quickly quenched online at a red-hot temperature of 369℃ and then cooled offline. (5) Tempering heat treatment: The tempering temperature is 240℃ and the tempering time is 85min, then air-cooled to room temperature; (6) Plate straightening: The uncoated areas at the head, tail, and sides of the composite plate are cut off, and the upper and lower carbon steel plates are separated from the coating. Then, the plates are straightened according to their shape. Finally, the coating surface is polished and sealed to obtain a 2+18+2mm thick double-sided high-strength and high-toughness tool composite plate. Example

[0021] This embodiment provides a high-strength and high-toughness tool composite plate, comprising a substrate and a cladding material. The chemical composition and mass percentage of the substrate are as follows: C: 0.09%, Si: 0.51%, Mn: 1.52%, P: 0.010%, S: 0.0018%, Nb: 0.035%, V: 0.011%, Ti: 0.016%, Ni: 0.59%, Cr: 0.76%, Mo: 0.11%, Als: 0.042%, with the remainder being Fe and unavoidable impurity elements. The chemical composition and mass percentage of the cladding material are as follows: C: 0.79%, Si: 0.72%, Mn: 0.71%, P: 0.026%, S: 0.012%, Cr: 13.98%, Mo: 0.19%, V: 0.18%, Ni: 0.26%; the remainder is Fe and unavoidable impurity elements.

[0022] This embodiment also provides a method for preparing a high-strength and high-toughness tool composite plate, which mainly includes the following steps: (1) Billet preparation: Based on the composition of the base material, the base material billet is obtained by converter smelting, LF refining, RH treatment, continuous casting and billet making with a thickness of 176mm; based on the composition of the cladding material, the cladding material billet is obtained by induction furnace melting, LF refining, VOD vacuum, die casting and forging with a thickness of 24mm. For carbon steel, a billet with a thickness of 64mm is selected. Assembly: such as Figure 1As shown, carbon steel 6-cladding material 2-substrate 1-cladding material 2-carbon steel 6 are stacked in sequence. The surfaces of the substrate and cladding material to be bonded need to be ground smooth to expose the metallic luster. The contact surface between the cladding material and the carbon steel is coated with an Al2O3-based release agent and dried at 100℃ for 20 minutes. Gas shielded welding is used to fix the cladding material to the substrate and the carbon steel around the perimeter to form gas shielded weld seam 5. Then, carbon steel sealing strip 3 is used to seal the perimeter of the cladding layer, and then submerged arc welding is used to seal the perimeter to form submerged arc weld seam 4. The composite billet is then vacuumed to obtain a 352mm thick composite billet. (3) Heating: The composite billet is heated in stages. First, the temperature is raised to 850℃ at a rate of 12℃ / min and held for 40min. Then, the temperature is raised to 1230℃ at a rate of 8℃ / min. The total heating time is 516min and the tapping temperature is 1198℃. (4) Controlled rolling and controlled cooling: The first two passes are rolled using symmetrical angle rolling, with the reduction rate controlled at 11-13%. Subsequent passes are rolled using low speed and high reduction, with a reduction rate ≥21% and an intermediate billet thickness of 101 mm. The finishing rolling start temperature is 861 ℃ and the finishing rolling temperature is 849 ℃. After rolling, the billet is quickly quenched online, with the reddening temperature controlled at 410 ℃, and then cooled offline. (5) Tempering heat treatment: The tempering temperature is 280℃ and the tempering time is 102min, then air-cooled to room temperature; (6) Plate straightening: The uncoated areas at the head, tail, and sides of the composite plate are cut off to separate the upper and lower carbon steel plates from the coating. Then, the plates are straightened according to their shape. Finally, the coating surface is polished and sealed to obtain a 3+22+3mm thick double-sided high-strength and high-toughness tool composite plate. The mechanical properties of the double-sided composite plates prepared in Examples 1 and 2 were tested, and the results are shown in Table 1.

[0023]

[0024] As shown in Table 1, the high-strength and high-toughness tool composite plate obtained by the present invention has a yield strength ≥450 MPa, tensile strength ≥550 MPa, elongation ≥21%, impact energy at -40℃ ≥160 J, shear strength ≥280 MPa, and surface hardness of the coating ≥52 HRC.

[0025] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A high-strength, high-toughness composite plate for cutting tools, comprising a substrate and a cladding material, characterized in that: The chemical composition and mass percentage of the substrate are as follows: C: 0.04-0.10%, Si: 0.35-0.55%, Mn: 1.2-1.6%, P≤0.015%, S≤0.002%, Nb: 0.02-0.05%, V: 0.01-0.03%, Ti: 0.015-0.025%, Ni: 0.5-1.0%, Cr: 0.6-0.8%, Mo: 0.05-0.15%, Als: 0.03-0.06%, with the remainder being Fe and unavoidable impurity elements; The chemical composition and mass percentage of the coating material are as follows: C: 0.7-0.9%, Si≤1.0%, Mn≤1.0%, P≤0.03%, S≤0.02%, Cr: 12-16%, Mo: 0.1-0.3%, V: 0.1-0.2%, Ni: 0.1-0.3%; the remainder is Fe and unavoidable impurity elements.

2. The high-strength, high-toughness tool composite plate according to claim 1, characterized in that: The composite board has a yield strength ≥450 MPa, tensile strength ≥550 MPa, elongation ≥21%, impact energy at -40℃ ≥160 J, shear strength ≥280 MPa, and surface hardness of the coating ≥52 HRC.

3. The method for preparing a high-strength, high-toughness tool composite plate according to claim 1, characterized in that: Specifically, the following steps are included: S1 billet preparation: Based on the composition of the base material, the billet is obtained by sequentially smelting in a converter, refining in an LF furnace, treating with RH, continuous casting, and billet making; based on the composition of the cladding material, the billet is obtained by sequentially smelting in an induction furnace, refining in an LF furnace, vacuum casting in a VOD furnace, die casting, and forging. S2 billet assembly: Stack carbon steel-cladding material-substrate-cladding material-carbon steel in the following order. Grind the substrate and cladding material surfaces to be joined until they are exposed to a metallic luster. Apply release agent to the contact surface between the cladding material and carbon steel and dry it. Use gas shielded welding to fix the cladding material to the substrate and carbon steel around the perimeter by spot welding at intervals. Then seal the perimeter of the cladding material with carbon steel sealing strips and weld the seal by submerged arc welding. Finally, vacuum the composite billet. S3 heating: Heat the composite billet to 1220~1280℃, and control the total heating time according to the thickness of the composite billet at 14~20min / cm. The tapping temperature is 1190~1250℃. S4 controlled rolling and cooling: The first two passes use symmetrical angle rolling with a reduction rate of 10-18%; subsequent low-speed high-reduction rolling with a reduction rate of ≥18% and the intermediate billet thickness is 1.8-2.6 times the rolling thickness; the finishing rolling start temperature is ≤890℃ and the finishing rolling temperature is 820-860℃; after rolling, online quenching is performed, followed by offline stacking cooling. S5 tempering heat treatment: Temper at 180~350℃, with tempering time controlled at 1.8~2.8min / mm based on the total thickness of the composite board, followed by air cooling to room temperature; S6 plate straightening: The head, tail and uncoated areas on both sides of the composite plate are cut off, the upper and lower carbon steel plates and the coating are separated, the plate shape is straightened, and the coating surface is polished and sealed to obtain a double-sided high-strength and high-toughness tool composite plate.

4. The method for preparing a high-strength, high-toughness tool composite plate according to claim 3, characterized in that: In step S2, the carbon steel used is a billet with a thickness of 64 mm, and the composite billet obtained after assembly has a thickness of 304-352 mm.

5. The method for preparing a high-strength, high-toughness tool composite plate according to claim 3, characterized in that: In step S3, the composite billet is heated in stages. First, the temperature is raised to 800-900℃ at a rate of 10-15℃ / min and held for 30-60min. Then, the temperature is raised to 1220-1280℃ at a rate of 5-8℃ / min.

6. The method for preparing a high-strength, high-toughness tool composite plate according to claim 3, characterized in that: In step S4, the rolling process is followed by online quenching, with a reddening temperature of 350–450°C.

7. The method for preparing a high-strength, high-toughness tool composite plate according to claim 3, characterized in that: In step S2, a release agent is applied to the contact surface between the cladding material and the carbon steel and then dried. The release agent is an Al2O3-based release agent, and the material is dried at a temperature of 80–120°C for 15–30 minutes.

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