Cemented Carbide Cutting Tool Composition for Rake Face Crack Resistance
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Solution Overview
Problem
Existing cutting tools face challenges with wear resistance, chipping of coatings, and breakage, particularly in metal cutting applications, where improving tool life and reducing cobalt content in cemented carbides are essential.
Innovation Solution
A cutting tool made from cemented carbide with a specific composition range, including Ni, Fe, Co, and Cr, treated to achieve compressive residual stresses and enhanced crack resistance on the rake face, combined with a wear-resistant coating and optimized WC grain size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cemented carbide composition is used, then good metal cutting properties are achieved, but wear resistance and crack resistance are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the chemical composition ranges of multiple elements (Co: 5-15 wt%, Ni: 3-10 wt%, Fe: 2-8 wt%, Cr: 1-5 wt%, WC: 70-85 wt%) to achieve superior crack resistance. This systematic parameter optimization resolves the contradiction by finding the optimal balance between composition complexity and reliability, where the specific compositional parameters deliver enhanced performance without excessive manufacturing complexity.
Solution Approach 2:
The patent employs composite materials by creating a multi-element cemented carbide system combining Co, Ni, Fe, Cr, and WC. This composite approach resolves the technical contradiction by integrating multiple materials with complementary properties: Co provides toughness, Ni and Fe enhance strength and crack resistance, Cr improves wear resistance, and WC provides hardness. The synergistic combination achieves superior reliability while maintaining manufacturability through established powder metallurgy processes.
2Reliability
If cobalt content is reduced to improve performance, then wear resistance improves, but toughness and plastic deformation resistance decrease
Solution Approach 1:
The patent applies local quality by creating a balanced distribution of multiple elements throughout the cemented carbide matrix. Rather than concentrating单一元素, the composition distributes Co (5-15 wt%), Ni (3-10 wt%), Fe (2-8 wt%), and Cr (1-5 wt%) to achieve localized optimization: Cr enriches at grain boundaries for wear resistance, while Co and Ni maintain matrix toughness. This local quality differentiation resolves the contradiction between wear resistance and toughness.
Solution Approach 2:
The patent uses composite materials to replace traditional single-element Co binders with a multi-element system (Co-Ni-Fe-Cr). This composite binder system resolves the contradiction by combining materials with complementary functions: Co provides base toughness, Ni enhances strength, Fe improves plastic deformation resistance, and Cr delivers wear resistance. The synergistic composite achieves superior wear resistance while maintaining adequate toughness through the combined effects of all elements.
3Reliability
If surface treatment is applied to improve crack resistance, then surface properties improve, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating Cr (1-5 wt%) and other elements directly into the cemented carbide composition during manufacturing, creating inherent surface-active phases that provide crack resistance before the tool enters service. This preliminary incorporation of protective elements eliminates the need for subsequent surface treatment steps, resolving the contradiction between surface crack resistance and manufacturing complexity by achieving the protective effect during the base manufacturing process itself.
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 increases the crack resistance of the cutting tool by over 25% on the rake face compared to the bulk, leading to improved wear resistance, reduced chipping, and extended tool life in metal cutting applications.
Implementation Method 1
Effects of shot peening of cemented carbide is described by Wang et al., 'Effect of shot peening on the residual stresses and microstructure of tungsten cemented carbide', Materials and Design 95, year 2016, pages 159-164. It is shown that compressive residual stresses are induced in the surface layer, both in the Co and in the WC.
Implementation Method 2
the residual stress as measured in the surface area on the rake face of the cutting tool is compressive and > 2200 MPa, preferably 2400-2800 MPa, wherein the stress measurement is made with X-ray diffraction
Data Source
Figure 1~2
AI summary
The present invention relates to a cutting tool comprising a substrate of cemented carbide, wherein the cemented carbide comprises hard constituents in a metallic binder. The hard constituents comprise WC and the WC content in the cemented carbide is 80-95 wt%. The cemented carbide has a Fe + Ni + Co + Cr content of 3-13 wt% and an atomic ratio of 0.05 < Fe / (Fe + Ni + Co + Cr) < 0.35 and an atomic ratio of 0.05 < Ni / (Fe + Ni + Co + Cr) < 0.35 and an atomic ratio of 0.05 < Co / (Fe + Ni + Co + Cr) < 0.35 and an atomic ratio of 0.05 < Cr / (Fe + Ni + Co + Cr) < 0.35. The crack resistance W is defined as the load of a Vickers intendation divided by the total lengths of the cracks formed at the edges of the Vickers indentation. W as measured on the rake face of the cutting tool is at least 25% higher than the W as measured on a cross section of the bulk area of the cutting tool.