Search

CN-121976185-A - Laser cladding preparation method of gradient composite material superhard coating cutter and cutter thereof

CN121976185ACN 121976185 ACN121976185 ACN 121976185ACN-121976185-A

Abstract

The invention discloses a gradient composite material superhard coating cutter and a laser cladding preparation method thereof, and belongs to the technical field of high-end cutter manufacture. The method comprises the steps of preprocessing a cutter matrix, designing a gradient powder system composed of metal-based powder, ceramic reinforced phase powder and rare earth oxide powder, forming a gradient coating with continuous transition of components and performances by cladding layer by layer on the matrix through coaxial powder feeding and micro powder feeding control based on a laser directional energy deposition or selective laser melting technology, synchronously applying ultrasonic vibration in the cladding process to refine grains, inhibit pores and cracks, and finally carrying out laser remelting, cutting edge laser passivation or sand blasting passivation post-treatment on the cutter. The tool prepared by the invention has the advantages that the coating and the matrix are metallurgically bonded, the interface is defect-free, the hardness is in gradient distribution (the surface hardness is more than or equal to 1600 HV), and the tool has high hardness, high toughness, high wear resistance and high shock resistance, and is especially suitable for high-performance cutting scenes of high-temperature, high-speed and difficult-to-process materials.

Inventors

  • REN GUANHUI
  • CHEN PENGYUE
  • LIU RIDONG

Assignees

  • 深圳市鑫金泉精密技术有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (10)

  1. 1. The laser cladding preparation method of the gradient composite material superhard coating cutter is characterized by comprising the following steps of: S1, preprocessing a matrix, namely cleaning, coarsening and preheating the surface of the cutter matrix; S2, preparing a gradient powder system, namely preparing raw materials at least comprising metal-based powder, ceramic reinforcing phase powder and rare earth oxide powder, wherein the ceramic reinforcing phase powder comprises at least one of TiC, WC, siC, al 2 O 3 、ZrO 2 , the rare earth oxide powder comprises at least one of CeO 2 、La 2 O 3 、Y 2 O 3 , and the addition amount of the rare earth oxide powder is 0.5-2.0% of the total powder mass; S3, gradient cladding forming, namely cladding the gradient powder system on the surface of the pretreated substrate layer by adopting a laser cladding technology to form a gradient coating with components continuously or stepwise changing with the tissue along the thickness direction, wherein ultrasonic vibration is synchronously applied in the laser cladding process, the ultrasonic frequency is 15-40 kHz, and the power is 200-1800W; And S4, post-treatment, namely, carrying out post-treatment including laser remelting, slow cooling and cutting edge passivation on the cutter after cladding.
  2. 2. The method according to claim 1, wherein in the step S2, the metal-based powder is Fe-based, co-based or Ni-based self-fluxing alloy powder, the gradient powder system further comprises 0.5% -2.0% of carbon nanotube reinforcement by mass, and the surface of the carbon nanotube is coated with a TiO 2 layer.
  3. 3. The method of claim 1, wherein in step S3, a laser directional energy deposition technology or a selective laser melting technology is adopted for cladding, and a double-cylinder powder feeder is matched with a micro powder feeding control system to realize real-time accurate control of gradient components, wherein the powder feeding speed is controlled to be 5-30 g/min.
  4. 4. The method of claim 3, wherein the laser cladding process parameters are laser power 800-2500W, scanning speed 3-15 mm/s, spot diameter 1-4 mm, interlayer lifting amount 0.2-0.5 mm, and shielding gas is argon or nitrogen.
  5. 5. The method according to claim 1, wherein in step S3, the gradient coating is structured such that the ceramic reinforcing phase content is increased from 0% to 30% -50% in gradient from the substrate interface to the coating surface, while the rare earth oxide content reaches 0.5% -1.5% in the surface layer region.
  6. 6. The method of claim 1, wherein in the step S4, the passivation of the cutting edge is performed by laser polishing or sand blasting passivation technology, laser polishing is performed by using a purple crust second laser or a flat-top beam, the laser power is 20-50W, the scanning speed is 100-500 mm/S, the light spot overlapping rate is 30-60%, the radius of the blunt edge is controlled to be 10-50 μm, and the sand blasting passivation is performed by using silicon carbide or glass beads, the pressure is 0.2-0.5 MPa, and the time is 20-60S.
  7. 7. The method according to claim 1, wherein in step S1, the tool body is a cemented carbide, a high-speed steel, a ceramic material or a composite layer structure tool body composed of a high-carbon high-chromium intermediate layer and a low-carbon stainless steel toughening layer.
  8. 8. A gradient composite superhard coated tool produced by the method of any one of claims 1 to 7, comprising a tool substrate and a gradient composite coating formed on the working surface of the tool substrate, wherein metallurgical bonding is performed between the gradient composite coating and the substrate, cracks and air hole defects are avoided at the interface, the microhardness of the coating is increased in a gradient manner from the bonding interface to the surface, and the surface hardness is not lower than 1600 HV.
  9. 9. The tool according to claim 8, wherein the tool has a number of impact resistance of 1300 or more when subjected to a chipping resistance test under the conditions of a cutting speed vc=250 m/min, a back draft ap=1.0 mm, and a feed f=0.2 mm/rev, and a cutting time of 40 or more minutes when subjected to a chipping resistance test under the same conditions and a 35CrMo alloy structural steel is processed, and the back face wearing amount reaches 0.2 mm.
  10. 10. The tool according to claim 8, wherein the gradient composite coating is a ceramic-ceramic gradient system or a metal-ceramic gradient system, wherein the ceramic-ceramic gradient system takes Al 2 O 3 -ZrO 2 eutectic ceramic as a matrix and is doped with TiCp particles in a gradient manner, and the metal-ceramic gradient system takes Fe-based, co-based or Ni-based alloy as a binding phase and is doped with WC, tiC or diamond particles in a gradient manner.

Description

Laser cladding preparation method of gradient composite material superhard coating cutter and cutter thereof Technical Field The invention relates to the field of advanced manufacturing and material surface engineering, in particular to a gradient composite material superhard coating cutter for high-end cutting and a preparation method based on a laser cladding technology. Background In the high-end manufacturing fields of modern precision machining, aerospace, energy equipment and the like, extremely severe requirements are put on the performance of a cutting tool, namely, extremely high hardness and wear resistance are required to cope with high-hardness difficult-to-machine materials, good toughness is required to resist impact load, and meanwhile, the performance is required to be kept stable under the conditions of high-temperature and high-speed cutting. The traditional high-speed steel, hard alloy and even coated cutting tool often have difficulty in simultaneously considering hardness and toughness due to homogenization of material performance or abrupt change of interface performance of a coating and a matrix, and are easy to have failure problems such as rapid abrasion, tipping, coating spalling and the like under extreme working conditions. To overcome the above-mentioned bottleneck, gradient functional materials are introduced into the field of cutters. The gradient material is an advanced material with components, tissues or properties continuously or quasi-continuously changed along a certain direction, and can effectively relieve stress concentration at an interface and realize optimized matching of different properties. For example, a gradient coating layer which continuously transits from a high-toughness matrix to an ultra-high-hardness surface is prepared on the surface of the cutter, so that the impact resistance and the wear resistance of the cutter are expected to be synchronously improved. The laser cladding technology is used as a high-energy density additive manufacturing and surface modification technology, and a metallurgically bonded compact coating can be formed on the surface of a substrate by rapidly melting and solidifying synchronously conveyed metal or ceramic powder under a high-energy laser beam. The technology has the advantages of concentrated heat input and small heat affected zone, and can realize arbitrary programming and gradient design of coating components by precisely controlling powder feeding components and technological parameters, thereby being an ideal means for preparing gradient coating cutters. However, the use of laser cladding techniques for preparing high performance gradient composite coated tools still faces a series of key technical challenges: The difficulty in accurate regulation and control of gradient components is how to realize uniform mixing and gradient distribution of multi-component powder, especially ceramic phase and metal phase in a micrometer-scale molten pool, and the prevention of component segregation is a key for ensuring the uniformity of the coating performance. The difficult problem of defect control in the cladding process is that the ceramic material and the metal material have huge differences in thermal physical properties (such as thermal expansion coefficient and melting point), thermal stress is very easy to generate in the rapid heating and cooling process of laser, so that the defects of cracks, air holes and the like of the coating occur, and the integrity of the coating is seriously damaged. The problem of the bonding strength of the coating and the complex tool matrix is that for the integral tool with spiral grooves, complex blades and the like, how to realize the uniform preparation of the high-quality gradient coating on the three-dimensional curved surface and ensure the firm bonding of the coating and the matrix, particularly the cutting edge area, is a difficult point for process implementation. The final treatment and reinforcement of the cutting edge area is that the cutting edge quality of the gradient coating cutter directly determines the cutting performance. How to carry out low-damage precise passivation and polishing on the high-hardness gradient coating cutting edge so as to remove microscopic defects and obtain ideal cutting edge morphology and sharpness is the last ring for improving the final use performance of the cutter. In the prior art, although there is a related patent (such as a comparative document CN 115874175B) for preparing a cutter coating by adopting laser cladding, the improvement of kitchen knife performance by a specific alloy powder formula and rare earth addition is mainly focused on, the problems of component regulation, defect suppression, three-dimensional forming, cutting edge processing and other engineering science problems of the gradient composite material coating in the preparation process are not systematically solved, precise control technologies such as ultrasonic assis