cBN Sintered Tool Binder Phase Optimization
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Solution Overview
Problem
Cubic boron nitride sintered body tools experience chipping due to insufficient binding between cBN particles when covered with a metal nitride layer, limiting their service life, especially in high-speed machining of strong cast iron materials.
Innovation Solution
A cBN sintered body tool with a binder phase comprising TiC and borides (TiB2 and AlB2) is developed, where the X-ray diffraction intensity ratio of TiC to borides is optimized to enhance bonding and wear resistance, and a metal layer is applied to the cBN particles to improve compatibility between heat resistance and chipping resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal nitride layer is applied to cBN particles to improve heat resistance, then heat resistance is improved, but chipping resistance deteriorates due to insufficient binding between cBN particles
Solution Approach 1:
The patent uses a composite binder phase comprising TiC and borides (TiB2 and AlB2) instead of a single material. This composite structure allows TiC to provide binding strength while borides contribute to heat resistance, resolving the contradiction between heat resistance and chipping resistance by combining materials with complementary properties in the binder phase
Solution Approach 2:
The patent optimizes the X-ray diffraction intensity ratio of TiC to borides and controls the content ratio of borides in the binder phase. By adjusting these parameters within specific ranges, the patent achieves the optimal balance between heat resistance and chipping resistance, preventing chipping while maintaining high temperature performance
2Strength
If high cBN content sintered body is used to achieve high hardness and strength, then machine property is improved, but service life deteriorates in hardened steel machining due to reaction between cBN and iron at high temperature
Solution Approach 1:
The binder phase acts as an intermediary between cBN particles and the workpiece. By using TiC and borides with low affinity for iron, the binder phase prevents direct contact and reaction between cBN and iron at high temperature, protecting the cBN particles from degradation while maintaining the structural integrity provided by high cBN content
Solution Approach 2:
The patent creates a composite sintered body with high cBN content (40-70 volume%) combined with a specifically designed binder phase. This composite structure leverages the high hardness of cBN while using the binder phase to prevent thermal degradation, achieving both high machine property and extended service life in hardened steel machining
3Temperature
If low cBN content sintered body is used to improve wear resistance at high temperature, then heat resistance is improved, but chipping resistance deteriorates due to low cBN particle contact ratio
Solution Approach 1:
The patent employs a composite binder phase with TiC and borides that provides superior high-temperature wear resistance. This allows the use of lower cBN content (40-70 volume% instead of higher) while maintaining adequate chipping resistance through the enhanced performance of the binder phase, achieving both heat resistance and sufficient strength
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 tool achieves a longer service life with high compatibility between heat resistance and chipping resistance, enabling efficient cutting of ductile and vermicular cast iron at high speeds, exceeding conventional tool performance.
Implementation Method 1
a binder phase comprising TiC and borides (TiB2 and AlB2) is developed, where the X-ray diffraction intensity ratio of TiC to borides is optimized to enhance bonding
Implementation Method 2
the X-ray diffraction intensity ratio of TiC to borides is optimized to enhance bonding and wear resistance
Data Source
AI summary
By high compatibility between heat resistance and chipping resistance of a cubic boron nitride sintered body, a long service life of a cubic boron nitride sintered body tool is achieved. The cubic boron nitride sintered body tool of the present invention has a cubic boron nitride sintered body including cubic boron nitride particles and a binder phase at at least a cutting edge. The cubic boron nitride sintered body includes 40-70 volume % of cubic boron nitride particles. The binder phase includes a first component and a second component. The first component includes TiC, and the second component includes one or both of TiB2 and AlB2. When the X-ray diffraction intensity of plane (200) of the first component is I1 and the X-ray diffraction intensity of plane (101) of said second component is I2, I1 is the maximum of the X-ray diffraction intensity of all components in the cubic boron nitride sintered body excluding the cubic boron nitride particles, and satisfies 0.01 ≤ I2/I1 ≤ 0.1.