Sintered Cermet Rotary Tool Surface Structure

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Solution Overview

Problem

Sintered cermets used in rotary tools face challenges with low thermal shock resistance and plastic deformation, leading to machining inaccuracies due to deformation during firing, especially in complex shapes.

Innovation Solution

A sintered cermet rotary tool with a surface structure comprising a high content of Ti-based hard phases and a binding phase, optimized through specific X-ray diffraction peak ratios and grain sizes, reduces deformation and enhances thermal shock resistance, achieving high machining accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If sintered cermet is used for rotary tools to achieve high hardness, then wear resistance is improved, but thermal shock resistance and plastic deformation resistance deteriorate

Engineering Contradiction:
ImprovehardnessVSAvoidthermal shock resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention creates a surface region with different properties from the interior by controlling the hard phase composition. The surface region contains predominantly Ti-based hard phases (TiCN, TiC, TiN) while the interior maintains a mixed composition. This local differentiation allows the surface to provide wear resistance while the interior provides thermal shock resistance and toughness, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses a composite structure with two distinct hard phase compositions: Ti-based hard phases in the surface region and a mixed composition (including WC, TaC, NbC) in the interior. This composite material approach allows combining the wear resistance of Ti-based phases with the thermal shock resistance and plastic deformation resistance of the mixed composition, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If sintered cermet with complicated shape is manufactured, then adaptability is improved, but manufacturing precision deteriorates due to deformation during firing

Engineering Contradiction:
Improvecomplex shape capabilityVSAvoiddimensional accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention creates a surface region with different properties from the interior by controlling the hard phase composition. The surface region contains predominantly Ti-based hard phases (TiCN, TiC, TiN) while the interior maintains a mixed composition. This local differentiation allows the surface to provide wear resistance while the interior provides thermal shock resistance and plastic deformation resistance, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses a composite structure with two distinct hard phase compositions: Ti-based hard phases in the surface region and a mixed composition (including WC, TaC, NbC) in the interior. This composite material approach allows combining the wear resistance of Ti-based phases with the thermal shock resistance and plastic deformation resistance of the mixed composition, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #40Composite materials

3Strength

If surface region with high abundance of black first hard phase is formed to improve impact resistance, then chipping resistance is improved, but thermal shock resistance remains insufficient

Engineering Contradiction:
Improvechipping resistanceVSAvoidthermal shock resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention creates a surface region with different properties from the interior by controlling the hard phase composition. The surface region contains predominantly Ti-based hard phases (TiCN, TiC, TiN) while the interior maintains a mixed composition. This local differentiation allows the surface to provide wear resistance while the interior provides thermal shock resistance and plastic deformation resistance, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention uses a composite structure with two distinct hard phase compositions: Ti-based hard phases in the surface region and a mixed composition (including WC, TaC, NbC) in the interior. This composite material approach allows combining the wear resistance of Ti-based phases with the thermal shock resistance and plastic deformation resistance of the mixed composition, resolving the contradiction between hardness and reliability.

Inventive Principle:
Principle #40Composite materials

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 optimized surface structure improves wear resistance, chipping resistance, and thermal shock resistance, resulting in higher dimensional accuracy and reduced deformation, making the sintered cermet suitable for complex-shaped rotary tools.

Implementation Method 1

a sintered cermet (1) that includes a hard phase (2) and a binding phase (3)

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 2

a content ratio in the second phase of a content of the at least one of group 4, 5, and 6 metals of the periodic table other than Ti than the content ratio in the first hard phase (2a)

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentEP2505289B1Rotation tool
Publication Date: 2019.06.05 KYOCERA CORP
  • EP2505289B1 patent drawingFigure 1(A)~1(C')
  • EP2505289B1 patent drawingFigure 2
  • EP2505289B1 patent drawingFigure 3

AI summary

Provided is a rotation tool such that thermal shock resistance is high, that the amount of cermet sintered body deformation resulting from burning can be made small, and that machining dimensional accuracy is high. The aforementioned rotation tool is formed of cermet (1) which consists of a hard phase (2) and a bonded phase (3), the aforementioned hard phase (2) being composed of a first hard phase (2a) having a high Ti content ratio and of a second hard phase (2b) having high content ratios of those metals in the fourth, fifth and sixth groups of the periodic table which are other than Ti. When X-ray diffraction measurement is made on the surface of the cermet (1), detection is made of two peaks which belong to a surface (220) of the hard phase (2). An intensity ratio Ib/Ia is a peak detected on a high angle side. Furthermore, a surface region (4) consisting mainly of the first phase exists with a thickness of 1 - 10 µ on the surface of the cermet (1); or a ratio ws/wi is equal to 1.1 - 1.7, where ws is the half-value width of a peak which belongs to a surface (200) of the bonded phase (3) on the surface of the cermet (1), and wi is the half-value width of a peak of the bonded phase inside the surface of the cermet (1).