AlTiN Coated Cemented Carbide for High-Speed Cutting
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Solution Overview
Problem
Existing cemented carbide cutting tool inserts lack sufficient wear resistance and toughness, especially during high-speed and high-feed metal cutting operations, leading to reduced tool life and edge security.
Innovation Solution
A cemented carbide insert with a WC-Co substrate and a PVD coating of Al x Ti 1-x N, where x=0.6-0.67, combined with specific compositions and geometries, is developed to enhance wear resistance and maintain toughness for semifinishing and finishing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high cutting speeds and feed rates are used to improve productivity, then productivity is improved, but heat generation increases leading to reduced tool life
Solution Approach 1:
The invention converts the harmful effect of high cutting temperatures into a beneficial outcome by designing a binder phase with Cr that forms heat-resistant carbide precipitates and maintains structural stability at elevated temperatures, allowing high-speed cutting without excessive heat damage
Solution Approach 2:
The invention modifies the thermal properties of the cemented carbide by changing the binder composition to include Cr at specific ratios, which alters the material's heat resistance and thermal stability, enabling operation at higher temperatures generated by high-speed cutting
2Strength
If PVD coating is applied to improve wear resistance, then wear resistance is improved, but coating integrity at high temperatures deteriorates
Solution Approach 1:
The invention changes the substrate's chemical composition and microstructure by incorporating Cr and Me elements in specific ratios, which modifies the thermal and mechanical properties of the substrate to better support PVD coatings under high-temperature cutting conditions
Solution Approach 2:
The invention creates a composite structure where the Cr-containing binder phase forms a stable substrate that provides thermal and mechanical support to the PVD coating, preventing coating degradation at high temperatures through the synergistic interaction between substrate and coating
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 solution significantly improves wear resistance and tool life, maintaining edge integrity and outperforming commercial references in various metal machining applications, including high-hardness materials and heat-resistant alloys.
Implementation Method 1
depositing by arc evaporation technique whilst maintaining a partial pressure of nitrogen in the recipient, and using the appropriate selection of active evaporation sources and -rates a wear resistant coating comprising a homogeneous Al x Ti 1 - x N-layer
Implementation Method 2
sintering the inserts in vacuum
Data Source
AI summary
The present invention relates to PVD coated cemented carbide cutting tool inserts semifinishing and finishing metal cutting operations. The cemented carbide cutting tool insert comprises a substrate and a wear resistant coating. The substrate comprises in addition to WC, 5.5-8.5 wt-% Co and Cr such that the Cr/Co weight ratio is 0.08-0.12 and also small amounts of Ti and Ta. The wear resistant coating is a homogeneous AlxTi1-xN-layer with x=0.6-0.67. The thickness of this layer is 1-3.8 µm.