Cemented Carbide Cutting Tool Surface for Titanium Alloy Wear
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Solution Overview
Problem
Titanium alloys pose challenges in processing due to high reactivity, leading to adhesion and chipping issues with cutting tools, particularly under high-speed conditions, where existing surface treatments fail to provide sufficient wearing resistance and tool longevity.
Innovation Solution
A cutting tool made of cemented carbide with a first hard phase of WC particles and a binder phase containing Co or Ni, featuring a surface layer with 1.0 GPa or more compressive residual stress and a thickness equal to or less than the average particle diameter, along with a second hard phase for enhanced heat resistance, and optionally a coating film for improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick surface layer is applied to improve wearing resistance, then wearing resistance is improved, but the surface area increases leading to more adhesion and chipping
Solution Approach 1:
The patent applies a thin surface layer (equal to or less than the average particle diameter of the first hard phase) only where needed to provide wearing resistance, rather than applying a thick uniform layer across the entire surface. This localized approach maintains the balance between wearing resistance and surface area contact.
Solution Approach 2:
The patent changes the thickness parameter of the surface layer to be equal to or less than the average particle diameter of the first hard phase, and controls the particle size ratio (B/A) to be 0.7 or more and less than 1. These parameter optimizations reduce surface area while maintaining wearing resistance.
2Reliability
If high compressive stress is applied to WC particles to improve wearing resistance, then wearing resistance is improved, but WC particles may become damaged or fragmented
Solution Approach 1:
The patent applies a controlled compressive residual stress of 1.0 GPa or more to the first hard phase, but carefully controls the particle size ratio (B/A) to be 0.7 or more and less than 1. This ensures the WC particles maintain their integrity while achieving the required wearing resistance through optimized stress application.
3Duration of action of stationary object
If existing surface treatments are applied to improve tool lifetime, then some wearing resistance is achieved, but chipping and adhesion under high-speed conditions are not sufficiently prevented
Solution Approach 1:
The patent uses a composite cemented carbide structure with multiple hard phases (first hard phase with WC particles and second hard phase) and a binder phase containing Co or Ni. This composite structure provides superior wearing resistance and prevents chipping and adhesion under high-speed conditions better than existing single-phase surface treatments.
Solution Approach 2:
The patent creates a surface layer part with distinct properties from the main body, where the surface layer has optimized hard phase distribution and compressive residual stress. This localized quality enhancement specifically addresses chipping and adhesion at the cutting surface while maintaining overall tool structure.
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 high wearing resistance and extended lifetime when processing titanium alloys, inhibiting chipping and adhesion, even under high-speed conditions, by maintaining the integrity of WC particles and reducing surface area contact.
Implementation Method 1
1.0 GPa or more of a compressive residual stress is applied to the first hard phase
Data Source
AI summary
A cutting tool is made of a cemented carbide including a first hard phase and a binder phase. The first hard phase is composed of WC particles. The binder phase contains Co and/or Ni. The cutting tool includes a main body part and a surface layer part. A thickness of the surface layer part is equal to or less than an average particle diameter of the first hard phase. On a surface of a plain part in a rake face, 1.0 GPa or more of a compressive residual stress is applied to the first hard phase. A ratio (B/A) of the average particle diameter (B) of the first hard phase on the surface of the plain part in the rake face to an average particle diameter (A) of the first hard phase on a cross section of the main body part is 0.7 or more and less than 1.