Graded Hard-Metal Body for Wear Resistance and Toughness
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Solution Overview
Problem
Conventional hard-metal bodies face a trade-off between wear resistance and toughness, with methods to enhance one property often compromising the other, and existing techniques for creating graded structures can result in fragile cores or the formation of brittle phases.
Innovation Solution
A method for creating a hard-metal body with a graded structure, where the surface region has a lower binder content and higher carbon content than the core, achieved through pre-sintering and carburization processes, allowing for a controlled carbon and tungsten gradient that enhances wear resistance and toughness without forming eta-phases or free carbon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the binder content is decreased to increase hardness and wear resistance, then wear resistance is improved, but toughness deteriorates
Solution Approach 1:
The patent applies local quality by creating a graded binder distribution where the surface region has lower binder content (higher hardness) and the core region has higher binder content (higher toughness). This allows different regions of the same hard-metal body to have optimized properties for their specific functional requirements, resolving the contradiction between wear resistance and toughness at the component level.
2Strength
If grain growth inhibitor is added to reduce carbide grain size and increase hardness, then hardness is improved, but toughness deteriorates
Solution Approach 1:
The patent applies local quality by creating a graded binder distribution where the surface region has lower binder content (higher hardness) and the core region has higher binder content (higher toughness). This allows different regions of the same hard-metal body to have optimized properties for their specific functional requirements, resolving the contradiction between wear resistance and toughness at the component level.
3Reliability
If carbon content is decreased to prevent eta-phase formation and improve toughness, then toughness is improved, but wear resistance deteriorates
Solution Approach 1:
The patent applies local quality by creating a graded binder distribution where the surface region has lower binder content (higher hardness) and the core region has higher binder content (higher toughness). This allows different regions of the same hard-metal body to have optimized properties for their specific functional requirements, resolving the contradiction between wear resistance and toughness at the component level.
4Ease of manufacture
If a uniform hard-metal structure is used to simplify manufacturing, then ease of manufacture is improved, but performance deteriorates due to inability to optimize both hardness and toughness
Solution Approach 1:
The patent applies parameter changes by systematically varying the binder content parameter through the structure of the hard-metal body, creating a continuous gradient from surface to core. This allows optimization of both hardness and toughness within a single component without requiring complex multi-step manufacturing processes, resolving the contradiction between manufacturing simplicity and performance optimization.
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 method results in a hard-metal body with significantly improved wear resistance and toughness, prolonging the working life of tools in high-wear applications by maintaining a high hardness-toughness coefficient in the surface region while avoiding brittleness in the core.
Implementation Method 1
the surface region has a lower binder content and higher carbon content than the core, achieved through pre-sintering and carburization processes
Implementation Method 2
allowing for a controlled carbon and tungsten gradient that enhances wear resistance and toughness
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D
AI summary
The invention relates to hard-metal body comprising a hard-metal, the hard-metal comprising tungsten carbide grains and metal binder comprising cobalt having a concentration of tungsten dissolved therein, the body comprising a surface region adjacent a surface and a core region remote from the surface, the surface region and the core region being contiguous with each other; the mean binder fraction of the core region being greater than that of the surface region; the mean carbon concentration within the binder being higher in the surface region than in the core region; to tools comprising same and methods of making same.