Hard Coating Composition for Welding-Resistant Cutting Tools
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Solution Overview
Problem
Coated tools used for high feed cutting of precipitation hardening stainless steel experience frequent welding chipping and insufficient welding resistance, leading to reduced performance and tool life.
Innovation Solution
A surface-coated cutting tool with a hard coating layer comprising a TiZr complex carbonitride or TiZrHf complex carbonitride layer, featuring a composition fluctuation structure with synchronized ZrHf and C content ratios, and an extremely small amount of chlorine, which enhances welding resistance and plastic deformation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a coated tool with TiZr carbonitride film or TiHf carbonitride film is used for high feed cutting of precipitation hardening stainless steel, then the tool can operate under severe conditions, but welding chipping easily occurs and welding resistance is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the coating layer by adding boron (0.01-5.00 mass%) and controlling chlorine content (0.01-5.00 mass%), along with specific ratios of Zr/Hf and C/N. This compositional modification transforms the coating from being prone to welding chipping to having exceptional welding resistance while maintaining high feed cutting capability.
Solution Approach 2:
The patent creates a composite coating structure combining TiZr complex carbonitride or TiZrHf complex carbonitride with boron and chlorine elements. This composite material approach integrates multiple functional elements: Ti and Zr/Hf provide hardness, boron enhances welding resistance, and chlorine improves plastic deformation resistance, achieving both high productivity and reliability.
2Productivity
If a coated tool with TiZr carbonitride film or TiHf carbonitride film is used for high feed cutting of precipitation hardening stainless steel, then the tool can operate under severe conditions, but minute chipping occurs and anomalous damage resistance is insufficient
Solution Approach 1:
The patent modifies physical and chemical parameters including adding boron (0.01-5.00 mass%) to change the material's damage resistance properties, controlling chlorine content (0.01-5.00 mass%) to enhance plastic deformation resistance, and optimizing the C/N ratio (0.20-0.80) to balance hardness and toughness, thereby preventing minute chipping and anomalous damage.
Solution Approach 2:
Boron acts as an intermediary element in the coating composition, mediating between the hard phase (TiZr/Hf carbonitride) and the matrix, improving the overall toughness and anomalous damage resistance of the coating while maintaining its cutting performance under severe conditions.
3Productivity
If a coated tool with TiZr carbonitride film or TiHf carbonitride film is used for high feed cutting of precipitation hardening stainless steel, then high feed cutting can be achieved, but normal wear proceeds rapidly
Solution Approach 1:
The patent optimizes compositional parameters including boron content (0.01-5.00 mass%), chlorine content (0.01-5.00 mass%), and the ratio of (Zr+Hf)/(Ti+Zr+Hf) (0.10-0.90), along with C/N ratio (0.20-0.80). These parameter changes create a coating that resists both adhesion and abrasion, significantly extending tool life during high feed cutting operations.
Solution Approach 2:
The coating is designed as a composite material system where TiZr/Hf complex carbonitride provides the base structure, boron enhances welding and wear resistance, chlorine improves plastic deformation resistance, and the controlled C/N ratio balances hardness and toughness, achieving exceptional long-term cutting performance.
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 tool exhibits exceptional welding resistance, plastic deformation resistance, and anomalous damage resistance, significantly improving tool life during high feed cutting of precipitation hardening stainless steel.
Implementation Method 1
the complex carbonitride layer contains TiZr complex carbonitride or TiZrHf complex carbonitride... the complex carbonitride layer has a composition fluctuation structure
Data Source
AI summary
A surface-coated cutting tool according to the present invention includes a tool body and a hard coating layer including a complex carbonitride layer containing a small amount of chlorine and (Ti(1-x)ZrxyHfx(1-y))(N(1-z)Cz) (0.10≤x≤0.90, 0<y≤1.0, 0.08<z<0.60), a ZrHf and C content ratios in cycles, a cycle distance between a maximum ZrHf content point and an adjacent minimum ZrHf content point and a cycle distance between a maximum C content point and an adjacent minimum C content point are 5 to 100 nm, an average value of content ratio differences Δx and Δz is 0.02 or more, a distance between the maximum ZrHf content point and the maximum C content point is ⅕ or less of the distance between a maximum content point and a minimum content point of adjacent ZrHf components, and a composition fluctuation structure is 10% or more.