Search

CN-122007425-A - Superfine crystal hard alloy cutter blank and preparation method thereof

CN122007425ACN 122007425 ACN122007425 ACN 122007425ACN-122007425-A

Abstract

The invention relates to the field of wedge-shaped riving knife preparation, and particularly discloses an ultrafine grain hard alloy knife blank, which comprises a knife blank, wherein the knife blank is formed by a needle point section, a transition section, a base section and a preformed channel, the transition section is connected with the needle point section and the base section end to end, the preformed channel is a through hole penetrating through the needle point section, the transition section and the base section, the preformed channel is arranged, the process of perforating on the knife blank can be omitted, the perforating process is not needed, the raw materials used for producing the wedge-shaped riving knife can be saved, a large amount of cost can be saved, more regulating components are used in the needle point section and the base section through the difference of the material proportion of the needle point section and the base section, so that finer grains can be formed, the hardness of the needle point section can be improved, the wear-resisting requirement of the preformed channel of the needle point section can be met, the base section can also improve the bending strength of the base section through reducing the proportion of the regulating components, the problem of brittle fracture during the installation of the wedge-shaped riving knife can be solved, and the service life of the wedge-shaped riving knife can be prolonged.

Inventors

  • ZHOU LI
  • HUANG YUXUAN
  • Jiang Huanyan
  • LIU YELIN
  • LIU YAN
  • ZHOU ZIMING

Assignees

  • 湖南科芯精工科技有限公司

Dates

Publication Date
20260512
Application Date
20251219

Claims (6)

  1. 1. The ultra-fine grain hard alloy cutter blank comprises a cutter blank (1) and is characterized in that the cutter blank (1) comprises a needle point section (1-1), a transition section (1-2), a base section (1-3) and a preformed channel (1-4), the transition section (1-2) is connected with the needle point section (1-1) and the base section (1-3) end to end, the transition section (1-2) and the base section (1-3) are of columnar structures, the needle point section (1-1) is of a wedge-shaped structure, and the preformed channel (1-4) is a through hole penetrating through the needle point section (1-1), the transition section (1-2) and the base section (1-3); The cutter blank (1) consists of 90-94% of tungsten carbide powder, 5-8% of adhesive and 1.2-2% of regulating and controlling components; the binder is formed by mixing cobalt powder and nickel powder according to the mass ratio of (3-5): 1, and the regulating and controlling components comprise 0.3-0.5% of alum carbide powder, 0.2-0.4% of chromium carbide powder, 0.4-0.7% of tantalum carbide powder and 0.3-0.4% of nano ruthenium powder.
  2. 2. An ultra-fine grain cemented carbide insert according to claim 1, characterized in that the content of the regulatory component in the tip section (1-1) is 30-50% higher than in the base section.
  3. 3. The ultra-fine grain cemented carbide insert according to claim 1, wherein the preformed channel (1-4) has a diameter of 0.045-0.055mm and a pore wall surface roughness Ra of 0.2 μm or less.
  4. 4. The ultra-fine grain cemented carbide insert according to claim 1, wherein the deviation of the axial line of the preform channel (1-4) from the axial line of the insert is less than or equal to 2 μm.
  5. 5. An ultra-fine grain cemented carbide insert according to claim 1, characterized in that the cemented carbide grain size d50=0.3-0.5 μm of the tip section (1-1) and the base section (1-3) grain size d50=0.6-0.8 μm form an ultra-fine grain structure that tapers in the axial direction.
  6. 6. The method for preparing the ultra-fine grain cemented carbide tool blank according to claims 1-5, comprising the steps of: s1, preparing raw materials, namely 90-94% of tungsten carbide powder (the average particle size of a needle tip section is 0.4 mu m, the average particle size of a base section is 0.7 mu m), 5-8% of adhesive (the adhesive is formed by mixing cobalt powder and nickel powder according to the mass ratio of 3-5:1), 0.3-0.5% of crystal grain inhibitor of vanadium carbide powder, 0.2-0.4% of chromium carbide powder, 0.4-0.7% of reinforcing agent of tantalum carbide powder (the particle size of tantalum carbide is 600-800 nm) and 0.3-0.4% of nano ruthenium powder; S2, adopting normal ethane as a medium, performing three-stage ball milling on the needle point raw material, namely firstly adding tungsten carbide and a binder, performing ball milling with 2-5mm tungsten carbide at 30r/min for 8 hours, then adding vanadium carbide and chromium carbide, performing ball milling for 3 hours, finally adding tantalum carbide and ruthenium powder, and performing ball milling with 0.3mm tungsten carbide grinding balls at 40r/min for 15 hours; S3, adopting the same ball milling process for the base section raw materials, and shortening the ball milling time of the final stage to 10 hours; S4, sequentially filling the ball-milled needle tip section powder and the base section powder into a gradient die with a tungsten steel core rod, wherein the diameter of the core rod is matched with that of a preformed channel; s5, placing the green body in a hydrogen atmosphere sintering furnace, and sintering according to the following curve: Heating to 500 ℃ at 3 ℃ per min, preserving heat for 2 hours, and removing the binder; heating to 700 ℃ at the temperature of 4 ℃ per min, and preserving heat for 1h; Finally, heating to 1400-1450 ℃ at 10 ℃ per min, and preserving heat for 1.5h; Cooling in sections after sintering, namely quenching the needle point section area at 8 ℃ per minute, and slowly cooling the base section area at 3 ℃ per minute to form a grain gradient; S6, removing the tungsten steel core rod after sintering, cleaning the preformed channel by adopting ultrasonic waves, removing residual powder, grinding the outer surface of the cutter blank, and ensuring that the straightness of the axis is less than or equal to 1 mu m.

Description

Superfine crystal hard alloy cutter blank and preparation method thereof Technical Field The invention relates to the field of wedge-shaped riving knife preparation, in particular to an ultrafine grain hard alloy knife blank and a preparation method thereof. Background The wedge-shaped chopper is used as a core consumable material of a semiconductor packaging lead bonding process, a through hole penetrating through the wedge-shaped chopper is a key channel of gold wire conduction, packaging precision and bonding reliability are directly determined, and at present, domestic products in the field have bottlenecks of insufficient material wear resistance, low through hole processing precision, poor batch stability and the like. The existing straight-through hole processing technology mainly faces two major problems, namely, when laser direct processing is adopted, the depth-diameter ratio of a straight-through hole of a riving knife is usually more than 100 (the diameter is 0.05 millimeter and the length is more than 5 millimeters), the processing precision is rapidly attenuated along with the depth, and a pore channel is easily blocked by a fused material, and secondly, a traditional hard alloy knife blank adopts a uniform component design, and can form the pore channel through subsequent processing, but the hardness and toughness of the material are insufficient in matching, so that the service life of the riving knife is only less than 60% of that of an imported product. The Hunan Ke core fine working team provides an innovative thought of 'knife blank preforming and laser trimming', a channel foundation is formed at a knife blank stage through die extrusion, and the bottleneck of processing precision is effectively broken through, but the existing preformed knife blank still has the defects that ultrafine-grain tungsten carbide powder is easy to agglomerate to cause uneven distribution of pore wall grains, the dimensional tolerance of the channel is difficult to control to be within +/-5 mu m, the whole mechanical property of the knife blank is uniform, the differentiation requirements of high wear resistance of a straight-through hole region and high toughness of a knife body connecting part cannot be met, the suitability of the preformed channel and the subsequent laser trimming is insufficient, and the precision processing cost is increased. Therefore, developing a hard alloy cutter blank with an accurate preformed hole structure, gradient mechanical properties and superfine crystal structure has important significance for realizing the domestic mass production of the wedge-shaped riving knife. Disclosure of Invention The invention aims to solve the technical problems mentioned in the background art and provides the following technical scheme: The superfine crystal hard alloy cutter blank comprises a cutter blank body, wherein the cutter blank body is composed of a needle point section, a transition section, a base section and a preformed channel, the transition section is connected with the needle point section and the base section end to end, the transition section and the base section are of columnar structures, the needle point section is of a wedge-shaped structure, and the preformed channel is a through hole penetrating through the needle point section, the transition section and the base section; the cutter embryo consists of 90-94% of tungsten carbide powder, 5-8% of binder and 1.2-2% of regulating and controlling components; the binder is formed by mixing cobalt powder and nickel powder according to the mass ratio of (3-5): 1, and the regulating and controlling components comprise 0.3-0.5% of alum carbide powder, 0.2-0.4% of chromium carbide powder, 0.4-0.7% of tantalum carbide powder and 0.3-0.4% of nano ruthenium powder. Preferably, the regulatory component is present in the tip section at a level of 30-50% higher than the base section. Preferably, the diameter of the preformed channel is 0.045-0.055mm, and the surface roughness Ra of the pore wall is less than or equal to 0.2 mu m. Preferably, the coaxiality deviation between the axis of the preformed channel and the axis of the cutter blank is less than or equal to 2 mu m. Preferably, the grain size d50=0.3-0.5 μm of the hard alloy of the needle tip section and the grain size d50=0.6-0.8 μm of the base section form an ultra-fine grain structure gradually changed along the axial direction. The preparation method of the superfine crystal hard alloy cutter blank comprises the following specific steps: S1, preparing raw materials, wherein 90-94% of tungsten carbide powder (the average particle size of a needle tip section is 0.4 mu m, the average particle size of a base section is 0.7 mu m), 5-8% of adhesive (the adhesive is formed by mixing cobalt powder and nickel powder according to the mass ratio of 3-5:1), 0.3-0.5% of vanadium carbide powder, 0.2-0.4% of chromium carbide powder, 0.4-0.7% of tantalum carbide powder (the particle size of tan