Coated Cutting Tool With α-Alumina Texture Control Under High Load
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Solution Overview
Problem
Conventional coated cutting tools exhibit excellent wear resistance but insufficient fracture resistance under high load cutting conditions, leading to reduced tool life.
Innovation Solution
The development of a coated cutting tool with an optimized α-type aluminum oxide layer, characterized by specific texture coefficients and residual stress values, along with a Ti compound layer, enhances both wear resistance and fracture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a coating layer with high wear resistance is applied on the substrate, then wear resistance is improved, but fracture resistance becomes insufficient under high load cutting conditions
Solution Approach 1:
The invention changes the crystallographic orientation parameters of the α-Al2O3 coating layer by controlling the texture coefficients TC(0012) and TC(1010) within specific ranges, and by controlling residual stress values, to simultaneously achieve high wear resistance and fracture resistance
Solution Approach 2:
The invention uses a composite coating structure with multiple layers including TiC, TiN, TiCN, and α-Al2O3 layers with specific thickness ratios and property combinations to achieve both wear resistance and fracture resistance
2Productivity
If cutting speed, feed and depth of cut are increased to improve productivity, then productivity is improved, but tool fracturing occurs due to increased load and temperature variations
Solution Approach 1:
The invention optimizes the residual stress parameters in the coating layer and substrate, controlling the residual stress of the α-Al2O3 layer to be within -300 to 300 MPa and the substrate residual stress to be within -2000 to -400 MPa, enabling the tool to withstand higher loads from increased cutting parameters without fracturing
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 improved wear and fracture resistance extend the tool life of the coated cutting tool, maintaining performance under demanding cutting conditions.
Implementation Method 1
in the α-type aluminum oxide layer, a texture coefficient TC (0,0,12) of a (0,0,12) plane represented by formula (1) below is from 4.0 or more to 8.4 or less, and a texture coefficient TC (1,0,10) of a (1,0,10) plane represented by formula (2) below is from 0.4 or more to 3.0 or less
Implementation Method 2
a residual stress value in a (1,1,6) plane of the α-type aluminum oxide layer is, in at least part thereof, from −300 MPa or higher to 300 MPa or lower
Implementation Method 3
a conventional coated cutting tool used for the cutting of, for example, steel or cast iron, is a coated cutting tool which is obtained by depositing, via chemical vapor deposition, a coating layer
Data Source
AI summary
A coated cutting tool comprising a substrate and a coating layer provided on a surface of the substrate, wherein: the coating layer comprises at least one α-type aluminum oxide layer; and a texture coefficient TC (0,0,12) of a (0,0,12) plane of the α-type aluminum oxide layer is from 4.0 or more to 8.4 or less; and a texture coefficient TC (1,0,10) of a (1,0,10) plane thereof is from 0.4 or more to 3.0 or less.