Cemented Carbide Composition for Low-Porosity Cutting Tools
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Solution Overview
Problem
Cemented carbides using zirconium carbide (ZrC) as a source material suffer from oxidation during sintering, leading to pores and reduced breakage resistance, resulting in decreased tool life and wear resistance.
Innovation Solution
A cemented carbide composition with specific phase ratios and distributions, including 65-85% tungsten carbide grains, 4-25% cobalt phase with 50% zirconium, and controlled pore percentages, optimized by formulas relating zirconium and cobalt content, to enhance wear and breakage resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If zirconium carbide (ZrC) is used as a source material to improve plastic deformation resistance and wear resistance, then wear resistance is improved, but pores are formed during sintering leading to decreased breakage resistance
Solution Approach 1:
The invention changes the chemical composition parameters by introducing tungsten (W) as a new element in addition to ZrC and Co. The specific parameter ranges (0.1-10 mass% W, 3-15 mass% Co, controlled ZrC content) are optimized to achieve both wear resistance and breakage resistance. This compositional parameter adjustment resolves the contradiction by finding a balanced formulation where W provides hardness while controlling pore formation.
Solution Approach 2:
The invention creates a composite material system combining multiple carbide phases (WC, ZrC) with a metal binder (Co). This composite approach allows the different components to compensate for each other's weaknesses: ZrC provides wear resistance, WC provides structural integrity, and Co binds the structure while controlling porosity. The synergistic combination resolves the contradiction between wear resistance and breakage resistance.
2Strength
If zirconium carbide (ZrC) is used as a source material to improve wear resistance, then wear resistance is improved, but tool life is decreased due to pore formation
Solution Approach 1:
The invention optimizes compositional parameters including W content (0.1-10 mass%), Co content (3-15 mass%), and ZrC content to control pore formation. By adjusting these parameters, the material achieves both wear resistance and extended tool life through reduced porosity and improved structural integrity.
Solution Approach 2:
Tungsten (W) acts as an intermediary element that mediates between the wear-resistant ZrC phase and the Co binder. W helps control pore formation and improves the overall structural integrity, thereby extending tool life while maintaining wear resistance provided by ZrC.
Data Source
Figure 1~2
Figure 3
AI summary
A cemented carbide includes a first phase and a second phase, wherein the first phase consists of a plurality of tungsten carbide grains, a content ratio of the first phase of the cemented carbide is 65 volume% or more and 85 volume% or less, a content ratio of the second phase of the cemented carbide is 4 volume% or more and 25 volume% or less, the second phase includes 50 mass% or more of cobalt, the second phase includes zirconium, a cobalt content ratio MCo of the cemented carbide is 3 mass% or more and 15 mass% or less, a and b of the cemented carbide indicate a relation of the following formula I: b<0.0485a+0.0001 where the a represents a percentage, (MZr/MCo)× 100, of a zirconium content ratio MZr of the cemented carbide in mass% with respect to the cobalt content ratio MCo of the cemented carbide in mass%, the a is more than 0 and 8 or less, the b represents an area percentage of pore in a first region of a cross section of the cemented carbide, and the first region is a region located within a distance of 50 µm from a surface of the cemented carbide in the cross section.