Cemented Carbide Cutting Edge Chemistry for Coating Adhesion
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Solution Overview
Problem
Cutting tools face issues with coating peeling due to lack of adhesion between the coating and the base material, and there is a need for tools with extended life, both coated and non-coated, to meet varying demands.
Innovation Solution
A cutting tool with a base material of cemented carbide or cermet, having controlled oxygen concentration and strain, and a coating made from specific elements, manufactured using alternative grinding processes to minimize oxygen incorporation and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating is formed on the base material to improve wear resistance, then the hardness and wear resistance are improved, but the coating may peel off due to lack of adhesion
Solution Approach 1:
The invention changes the chemical composition parameter of the base material by controlling oxygen concentration (less than or equal to 1 at.%) and carbon concentration (less than or equal to 3 at.%) at the cutting edge face. This compositional control prevents excessive oxidation that would create a weak boundary layer, thereby ensuring strong coating adhesion while maintaining wear resistance
Solution Approach 2:
The invention performs preliminary control of the base material's chemical composition before coating formation. By pre-controlling oxygen and carbon concentrations at the cutting edge face through specific manufacturing processes, the base material is prepared in advance to ensure optimal coating adhesion, preventing peeling issues that would otherwise occur during or after coating application
2Productivity
If the base material is machined using conventional grinding processes, then the manufacturing efficiency is maintained, but oxygen is incorporated into the base material reducing its performance
Solution Approach 1:
The invention uses periodic alternation between wet grinding and dry grinding processes. During wet grinding, oxygen incorporation is prevented by the lubricant barrier. During dry grinding, material is removed but oxygen incorporation is minimized by the periodic interruption. This periodic switching maintains manufacturing efficiency while controlling oxygen concentration to less than or equal to 1 at.% at the cutting edge face
Solution Approach 2:
The invention extracts or removes oxygen from the base material by using dry grinding processes that mechanically remove oxygen-containing layers formed during wet grinding. This extraction process reduces oxygen concentration to acceptable levels while maintaining the productivity benefits of wet grinding through selective removal of oxidized surfaces
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 cutting tool exhibits improved wear resistance, fracture resistance, and extended life, with reduced peeling and crack extension, and enhanced adhesiveness between the base material and coating.
Implementation Method 1
The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face
Implementation Method 2
a first grinding process of alternately repeating wet grinding and dry grinding
Data Source
AI summary
A cutting tool includes a base material. The base material is a cemented carbide or a cermet. A surface of the base material includes a rake face, a flank face, and a cutting edge face connecting the rake face to the flank face. The base material has an oxygen concentration of less than or equal to 1 at. % at a depth position of 0.4 μm from the cutting edge face.