Cemented Carbide Grain Orientation for Crack-Resistant Cutting Tools
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Solution Overview
Problem
There is a growing demand for cost-effective tools with extended service life, particularly in high-efficiency processing applications, as existing cemented carbides do not adequately address the need for prolonged tool durability and crack resistance.
Innovation Solution
A cemented carbide composition comprising tungsten carbide grains and a binder phase with specific volume content ratios and orientation difference distributions, enhancing anisotropy and crack suppression, along with a preferred binder phase composition, is developed to improve tool longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cemented carbide compositions are used, then manufacturing cost is reduced, but tool service life and crack resistance are insufficient
Solution Approach 1:
The invention changes the critical parameter of grain orientation distribution by controlling the frequency of orientation differences between adjacent tungsten carbide grains to be 0.010-0.200 in the 29.5°-30.5° range. This parameter change fundamentally alters the material's crack resistance properties, enabling extended tool service life without requiring expensive material substitutions or complex manufacturing processes
Solution Approach 2:
The invention applies local quality control by specifically targeting the orientation relationship between adjacent grains at interfaces. By controlling the orientation difference distribution in this localized region, the invention achieves improved overall material performance and crack resistance while maintaining cost-effective manufacturing
2Strength
If binder phase content is increased to improve toughness, then crack resistance improves, but hardness and wear resistance deteriorate
Solution Approach 1:
The invention changes the controlling parameter from binder phase content to grain orientation distribution. By controlling the frequency of orientation differences between adjacent grains, the invention achieves crack resistance improvement without the negative trade-off of reduced hardness and wear resistance that occurs when increasing binder phase content
Solution Approach 2:
The invention substitutes the mechanical reinforcement approach (increasing binder phase) with a microstructural orientation approach. Instead of relying on more binder material to prevent cracks, the invention uses controlled grain orientation relationships to deflect and suppress crack propagation, maintaining both toughness and surface hardness
Data Source
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AI summary
A cemented carbide including tungsten carbide grains and a binder phase, in which a total content of the tungsten carbide grains and the binder phase in the cemented carbide is no less than 80 vol%, a content of the binder phase in the cemented carbide is no less than 0.1 vol% and no more than 20 vol%, in a histogram showing distribution of orientation differences between adjacent pairs each consisting of two of the tungsten carbide grains adjacent to each other in the cemented carbide, a first peak is present in a class of the orientation differences of no less than 29.5° and less than 30.5°, the classes along a horizontal axis of the histogram indicate the orientation differences, and a width of the class is 1.0°, and a frequency along a vertical axis of the histogram indicates a ratio of the number of the adjacent pairs belonging to each class to the number of all of the adjacent pairs in the cemented carbide.