Binderless Polycrystalline Cubic Boron Nitride for Iron Cutting
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Solution Overview
Problem
Cubic boron nitride sintered bodies used for cutting iron-based materials at high speed suffer from chipping and cracking due to increased thermal load, leading to reduced tool life.
Innovation Solution
Manufacture polycrystalline cubic boron nitride with a high cubic boron nitride content (>98.5% by volume), low dislocation density (≤8×10^15/m^2), and controlled grain size (0.1-0.5 µm) using a specific heating and pressurizing process, avoiding binders and maintaining stability through controlled temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If binder is added to cubic boron nitride sintered bodies, then ease of manufacture is improved, but strength and thermal diffusivity deteriorate
Solution Approach 1:
The invention extracts and removes the binder component from the cubic boron nitride sintered body composition. By producing a binderless sintered body through direct sintering of cubic boron nitride particles under ultra-high pressure and temperature, the harmful binder is completely eliminated, thereby improving strength and thermal diffusivity without compromising manufacturability
2Ease of manufacture
If binder is added to cubic boron nitride sintered bodies, then ease of manufacture is improved, but thermal diffusivity deteriorates
Solution Approach 1:
The invention extracts and removes the binder component from the cubic boron nitride sintered body composition. By producing a binderless sintered body through direct sintering of cubic boron nitride particles under ultra-high pressure and temperature, the harmful binder is completely eliminated, thereby improving thermal diffusivity while maintaining ease of manufacture through the direct sintering process
3Productivity
If cutting speed is increased for iron-based materials, then productivity is improved, but thermal load increases causing chipping and cracking
Solution Approach 1:
The invention changes the material parameters of the cutting tool by eliminating the binder and achieving a homogeneous cubic boron nitride structure with controlled grain size distribution. This parameter change results in superior thermal conductivity and mechanical strength, enabling the tool to withstand the thermal load generated during high-speed cutting of iron-based materials without chipping or cracking
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 resulting polycrystalline cubic boron nitride achieves enhanced strength, toughness, and thermal stability, resulting in extended tool life during high-speed processing of iron-based materials.
Implementation Method 1
a hexagonal boron nitride is directly converted into a cubic boron nitride under ultra-high pressure and ultra-high temperature
Implementation Method 2
heating and pressurizing the hexagonal boron nitride powder to a temperature greater than or equal to 1900°C and less than or equal to 2400°C and to a pressure greater than or equal to 8 GPa
Implementation Method 3
heating and pressurizing the hexagonal boron nitride powder to a temperature greater than or equal to 1900°C and less than or equal to 2400°C and to a pressure greater than or equal to 8 GPa
Data Source
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AI summary
There is provided a polycrystalline cubic boron nitride containing a cubic boron nitride at a content greater than or equal to 98.5% by volume, the polycrystalline cubic boron nitride having a dislocation density less than or equal to 8×1015/m2.