Polycrystalline Cubic Boron Nitride Drill Bit Insert
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Solution Overview
Problem
Polycrystalline diamond compacts used in drill bit inserts have lower toughness and fracture resistance compared to cemented carbide, leading to premature wear and reduced tool life, especially when drilling through super-hard rock layers, and are not suitable for high-temperature conditions or Fe/Ni mines due to their high affinity and hardness.
Innovation Solution
A drill bit insert with a polycrystalline cubic boron nitride compact sintered using catalytic metals like Al, Co, Ni, Mn, and Fe, containing 70-95 vol% cubic boron nitride and metallic additives such as W, Mo, Cr, V, Zr, and Hf, providing improved toughness and wear resistance while maintaining hardness comparable to polycrystalline diamond, allowing for effective reuse through resharpening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polycrystalline diamond compact is used as a hard layer on a drill bit insert, then wear resistance is improved, but toughness and fracture resistance deteriorate
Solution Approach 1:
The patent applies composite materials by creating a polycrystalline cubic boron nitride (cBN) compact that combines superhard cBN particles with a metallic binder phase. This composite structure provides both the wear resistance of the cBN particles and the toughness of the metallic binder, resolving the contradiction between hardness and fracture resistance. The cBN phase contributes to wear resistance while the metallic binder phase enhances toughness and fracture resistance.
2Strength
If a polycrystalline diamond compact is used to increase hardness, then wear resistance is improved, but the material cannot be used in high-temperature conditions above 700°C
Solution Approach 1:
The patent applies parameter changes by substituting the material composition from polycrystalline diamond to polycrystalline cubic boron nitride. This material substitution changes the thermal stability parameter, enabling the cutting tool to withstand temperatures exceeding 1000°C while maintaining its cutting edge, thus resolving the temperature limitation of diamond-based tools.
3Strength
If a polycrystalline diamond compact is used, then wear resistance is improved, but the material has high affinity with Fe and Ni making it unsuitable for drilling in Fe or Ni mines
Solution Approach 1:
The patent applies parameter changes by changing the material composition from diamond to cubic boron nitride. This substitution fundamentally alters the chemical reactivity parameters, making the material chemically inert toward Fe and Ni. The cBN material does not exhibit the high affinity that diamond shows toward these metals, enabling effective drilling in Fe and Ni mines while maintaining wear resistance.
4Reliability
If a hard layer is fractured and the cemented carbide body is exposed, then wear is promoted, but frequent exchange of drill bits reduces work efficiency
Solution Approach 1:
The patent applies composite materials by creating a polycrystalline cubic boron nitride compact with a metallic binder phase that provides enhanced toughness. This composite structure prevents catastrophic fracture and protects the underlying cemented carbide body from exposure and accelerated wear, thereby extending tool life and reducing the frequency of drill bit exchanges, which improves overall work efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The drill bit insert achieves extended tool life with enhanced wear and fracture resistance, enabling efficient drilling in super-hard rock layers and high-temperature conditions, including Fe/Ni mines, with reduced exchange frequency and improved durability through resharpening.
Implementation Method 1
polycrystalline cubic boron nitride compact sintered using a catalytic metal containing Al and at least one selected from the group consisting of Co, Ni, Mn, and Fe
Implementation Method 2
catalytic metal containing Al and at least one selected from the group consisting of Co, Ni, Mn, and Fe
Data Source
Figure 1
Figure 2
AI summary
A drill bit insert attached to a tip portion of a drill bit to perform drilling, includes: an insert body (1) that includes: a rear end portion buried in a bit body of the drill bit; and a tip portion protruding from a surface of the drill bit and tapered toward a tip side of the insert body, in which a surface of at least the tip portion of the insert body (1) made of poly crystalline cubic boron nitride compact (4) sintered using a catalytic metal containing and at least one selected from the group consisting of Co, Ni, Mn, and Fe and containing 70 vol% to 95 vol% of cubic boron nitride.