Composite cBN Sintered Material for Low-Adhesion Wire Drawing Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cubic boron nitride sintered materials used in tools face issues such as adhesion to wire materials during wire drawing, leading to wire breakage or surface scratches due to friction, which reduces tool life and deteriorates the surface condition of the wire.
Innovation Solution
A composite sintered material comprising cubic boron nitride grains with controlled dislocation density, median diameter, and specific ratios of hexagonal and wurtzite boron nitride grains, along with minimal impurities, is used to enhance tool life by improving slidability, wear resistance, and crack propagation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cubic boron nitride sintered material is used as tool material, then hardness and thermal stability are improved, but adhesion to wire material occurs during wire drawing
Solution Approach 1:
The patent applies local quality by creating a composite structure where different phases (cubic boron nitride, hexagonal boron nitride, and wurtzite-type boron nitride) are distributed throughout the material. Each phase contributes different properties: cBN provides hardness and wear resistance, while hBN and wBN phases reduce adhesion and friction. This heterogeneous composition allows the material to exhibit locally different characteristics that collectively solve the adhesion problem while maintaining overall hardness.
Solution Approach 2:
The patent employs composite materials by combining multiple boron nitride phases in a sintered structure. The composite consists of cubic boron nitride grains (50-95 vol%) for hardness, hexagonal boron nitride grains (5-40 vol%) for adhesion reduction, and wurtzite-type boron nitride grains (5-40 vol%) for friction reduction. This multi-phase composite approach resolves the contradiction between hardness and adhesion by integrating materials with complementary properties.
2Ease of manufacture
If binder is added to cubic boron nitride sintered material, then manufacturing ease is improved, but strength and thermal diffusivity decrease
Solution Approach 1:
The patent applies the taking out principle by completely eliminating the binder component from the sintered material composition. Instead of using a binder to hold grains together, the material relies on the interlocking structure of cBN, hBN, and wBN grains bonded through sintering. This extraction of the binder removes the source of strength reduction and thermal diffusivity degradation while maintaining manufacturability through the sintering process.
3Duration of action of moving object
If friction is reduced during wire drawing, then tool life is improved, but adhesion control becomes more difficult
Solution Approach 1:
The patent merges multiple functions into a single material system. The composite sintered material simultaneously provides wear resistance (through hard cBN phases), adhesion reduction (through hBN phases), and friction reduction (through wBN phases). By combining these functionalities in one integrated material rather than using separate coating or lubrication systems, the patent achieves extended tool life while maintaining effective adhesion 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 composite sintered material achieves a longer tool life without deteriorating the surface condition of the wire material, particularly in wire drawing processes, by reducing adhesion and frictional heat, and maintaining structural integrity.
Implementation Method 1
the composite sintered material can attain a long tool life without deteriorating a surface condition of a wire material particularly in a wire drawing process when used as a tool material
Implementation Method 2
improving slidability, wear resistance, and crack propagation resistance
Data Source
Figure 1~2
Figure 3~4
AI summary
A composite sintered material includes: cubic boron nitride grains; and hexagonal boron nitride grains or the hexagonal boron nitride grains and wurtzite type boron nitride grains, wherein a dislocation density of the cubic boron nitride grains is more than or equal to 1 × 1015/m2 and less than or equal to 1 × 1017/m2, a median diameter d50 of equivalent circle diameters of the cubic boron nitride grains is more than or equal to 10 nm and less than or equal to 500 nm, and a relationship of the following expression 1 is satisfied: 0.015≤Vh+Vw/Vc+Vh+Vw≤0.5, where Vc represents a volume-based content ratio of the cubic boron nitride grains, Vh represents a volume-based content ratio of the hexagonal boron nitride grains, and Vw represents a volume-based content ratio of the wurtzite type boron nitride grains.