Cemented Carbide Composition for Heat-Resistant Cutting Tools

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Solution Overview

Problem

Cutting tools experience reduced lifespan when cutting difficult-to-cut materials like Inconel and titanium alloys due to high temperatures, requiring improved heat and reaction resistance.

Innovation Solution

A cemented carbide composition with a first hard phase of tungsten carbide, a second hard phase containing niobium or tantalum, and a binder phase of cobalt, nickel, and chromium, where the volume ratio of the second hard phase to the cemented carbide is greater than 1.2, providing enhanced heat and reaction resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cemented carbide is used for cutting difficult-to-cut materials, then cutting ability is achieved, but tool lifespan is reduced due to high temperatures

Engineering Contradiction:
Improvetool lifespanVSAvoidcutting temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent employs a composite cemented carbide material consisting of tungsten carbide grains (first hard phase), carbide grains containing niobium or tantalum (second hard phase), and a binder phase with cobalt, nickel, and chromium. This composite structure combines the high hardness of WC with the heat resistance of Nb/Ta carbides, enabling the tool to withstand high cutting temperatures while maintaining structural integrity and extending tool lifespan.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes specific compositional parameters: the binder phase contains 3-15 mass% chromium, and the ratio A/B (volume ratio of second hard phase to total niobium+tantalum content) is controlled to be more than 1.2. These parameter changes enhance the material's heat resistance and reaction resistance, allowing the cutting tool to maintain performance at elevated temperatures.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If heat resistance is improved by adding niobium or tantalum carbide, then reaction resistance increases, but material complexity increases

Engineering Contradiction:
Improvereaction resistanceVSAvoidmaterial composition complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by concentrating niobium or tantalum specifically in the second hard phase carbide grains, rather than distributing these elements uniformly throughout the material. This localized approach provides heat and reaction resistance precisely where needed at the grain level, while keeping the overall material composition and processing relatively simple.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS12005507B2Cemented carbide and cutting tool including same as substrate
Publication Date: 2024.06.11 SUMITOMO ELECTRIC INDUSTRIES LTD

AI summary

A cemented carbide includes a first hard phase, a second hard phase, and a binder phase, wherein the first hard phase is composed of tungsten carbide grains, the second hard phase is composed of carbide grains including niobium or tantalum as a constituent element, the binder phase includes cobalt, nickel, and chromium as constituent elements, at least part of the carbide grains further include tungsten as a constituent element, and when a volume ratio of the second hard phase to the cemented carbide is represented by A volume % and a volume ratio of a total of a niobium element and a tantalum element to the cemented carbide is represented by B volume %, a ratio A/B of A to B is more than 1.2.