Cemented Carbide Cutting Tool Microstructure Against Early Breakage

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Solution Overview

Problem

Cutting tools with cemented carbide substrates face issues of unpredictable tool life due to early breakages and lack of resistance against wear and plastic deformation, leading to unexpected downtime in machining operations.

Innovation Solution

A cutting tool with a cemented carbide substrate containing a well-distributed gamma phase and a reduced amount of abnormal WC grains, characterized by specific area fractions and distribution, along with a binder phase enriched surface zone depleted of gamma phase, to enhance wear resistance and tool longevity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If cutting tools are replaced before they break to maximize production, then productivity is improved, but unexpected down time increases due to early tool breakage

Engineering Contradiction:

ImproveproductionVSAvoidtool life predictability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the gamma phase distribution (N<80 μm²) and abnormal WC grain area fraction (0-0.03) in the cemented carbide substrate. These microstructural parameter optimizations reduce crack formation and propagation, making tool life more predictable and reducing early breakages, thereby resolving the contradiction between maximizing productivity through preventive replacement and maintaining reliability against unexpected failures

Inventive Principle:

Principle #35Parameter changes

2Strength

If the cemented carbide substrate contains gamma phase to improve wear resistance, then durability is improved, but early breakages occur due to unpredictable tool life

Engineering Contradiction:

Improvewear resistanceVSAvoidtool life predictability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform gamma phase distribution where the binder phase is enriched at the surface zone while being depleted deeper in the substrate. This localized differentiation optimizes wear resistance at the surface while maintaining structural integrity throughout, reducing early breakages and improving tool life predictability without sacrificing durability

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If abnormal WC grains are present in the cemented carbide, then manufacturing is easier, but crack formation increases leading to early breakage

Engineering Contradiction:

ImprovemanufacturingVSAvoidcrack resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent applies parameter changes by setting the area fraction of abnormal WC grains to 0-0.03, significantly reducing their presence in the cemented carbide substrate. This parameter optimization reduces crack formation and propagation while maintaining manufacturing feasibility, thereby improving crack resistance without making the manufacturing process excessively complex

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11261510B2Cutting tool

Publication Date: 2022.03.01 SANDVIK INTELLECTUAL PROPERTY AB

AI summary

A cutting tool made of a cemented carbide substrate of WC, a metallic binder phase and gamma phase is provided. The cemented carbide has a well distributed gamma phase and a reduced amount of abnormal WC grains. The cutting tool has a more predicted tool life and an increased resistance against plastic deformation.