High-cBN Sintered Body Binder Control to Prevent Tool Chipping
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Solution Overview
Problem
High-cBN sintered bodies used in cutting tools experience sudden chipping due to weak binding strength, leading to shortened tool life and increased costs, as conventional methods to improve binding ratios are insufficient.
Innovation Solution
A cubic boron nitride sintered body with a binder containing WC, Co, and Al, where the binder includes a controlled amount of W2Co21B6, and the use of organic cBN powder to suppress the generation of W2Co21B6, which acts as a brittle origin of particle detachment, is employed, resulting in improved binding and extended tool life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the content ratio of cubic boron nitride particles is increased to create a high-cBN sintered body, then the hardness and cutting performance are improved, but the binding strength between particles decreases causing sudden chipping
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by specifying it contains WC, Co, and an Al compound, with controlled amounts of W2Co21B6 (0-10 mass%). This parameter optimization allows the binder to maintain adequate binding strength while accommodating high cBN content (85-100 vol%), resolving the contradiction between hardness and binding strength
Solution Approach 2:
The invention creates a composite binder system combining multiple materials (WC, Co, Al compound, and controlled W2Co21B6) to achieve synergistic effects. This composite approach allows the binder to simultaneously provide binding strength and compatibility with high cBN content, preventing sudden chipping while maintaining high hardness
2Productivity
If the content ratio of cubic boron nitride particles is increased to create a high-cBN sintered body, then the cutting performance is improved, but the tool life decreases due to particle detachment
Solution Approach 1:
The invention optimizes the binder composition parameters (WC, Co, Al compound ratios and W2Co21B6 content at 0-10 mass%) to achieve the right balance between enabling high cBN content for cutting performance and maintaining binding strength for tool life, preventing particle detachment
Solution Approach 2:
The invention allows the use of W2Co21B6 in controlled amounts (0-10 mass%) which can be a brittle phase, but limits its content to prevent harmful effects. This controlled use of a potentially problematic phase allows optimization of cutting performance while managing its impact on tool life through precise compositional control
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 approach results in a cubic boron nitride sintered body with reduced particle detachment and extended tool life, as evidenced by lower X-ray diffraction intensity ratios and increased hardness, leading to longer cutting tool lifespan.
Implementation Method 1
A cubic boron nitride sintered body includes more than or equal to 85 volume percent and less than 100 volume percent of cubic boron nitride particles, and a remainder of a binder
Implementation Method 2
the binder contains WC, Co, and an Al compound
Implementation Method 3
when IA represents an X-ray diffraction intensity of a (111) plane of the cubic boron nitride particles, IB represents an X-ray diffraction intensity of a (100) plane of the WC, and IC represents an X-ray diffraction intensity of a (420) plane of the W2CO21B6
Data Source
AI summary
Provided is a cubic boron nitride sintered body including more than or equal to 85 volume percent and less than 100 volume percent of cubic boron nitride particles, and a remainder of a binder, wherein the binder contains WC, Co, and an Al compound, the binder contains W2Co21B6, and, when IA represents an X-ray diffraction intensity of a (111) plane of the cubic boron nitride particles, IB represents an X-ray diffraction intensity of a (100) plane of the WC, and IC represents an X-ray diffraction intensity of a (420) plane of the W2Co21B6, a ratio IC/IA of the IC to the IA is more than 0 and less than 0.10, and a ratio IC/IB of the IC to the IB is more than 0 and less than 0.40.