Fe-Cr Metal Powder Composition for High-Density Sintering

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Solution Overview

Problem

Current powder metallurgy methods require additional treatments like hot isostatic pressing (HIP) to achieve high-density sintered bodies, which increase workload and cost, necessitating a metal powder composition that can enhance densification without additional processing.

Innovation Solution

A metal powder composition with specific proportions of Fe, Cr, C, Si, Mn, and Ni, along with selected elements like V, Y, Zr, Nb, and Hf, forming a martensite crystal structure, optimized to enhance sinterability and densification during the sintering process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If additional treatments like hot isostatic pressing (HIP) are performed to achieve high-density sintered bodies, then the density and mechanical properties are improved, but the workload and production cost increase significantly

Engineering Contradiction:
Improvedensity of sintered bodyVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the chemical composition parameters of the metal powder by adding specific elements (Ti: 0.01-0.5 mass%, Nb: 0.01-0.5 mass%, V: 0.01-0.5 mass%) within controlled ranges. These compositional parameter changes enable the sintered body to achieve high density through conventional sintering alone, eliminating the need for additional HIP treatment and thereby improving production efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite metal powder system combining Fe-based principal components with multiple alloying elements (Ti, Nb, V, and others). This composite material approach produces synergistic effects during sintering that enhance densification, allowing high-density sintered bodies to be obtained without additional processing steps.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If additional treatments like hot isostatic pressing (HIP) are performed to achieve high-density sintered bodies, then the density and mechanical properties are improved, but the production cost increases

Engineering Contradiction:
Improvedensity of sintered bodyVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By adjusting the chemical composition parameters (adding Ti, Nb, V within specific ranges), the invention enables conventional sintering to produce high-density bodies. This parameter change eliminates expensive additional treatments, directly reducing production cost while maintaining high manufacturing precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses small amounts of affordable alloying elements (Ti, Nb, V) as additives in the metal powder composition. These inexpensive elements provide the necessary densification effect during sintering, replacing the need for expensive additional HIP treatment and thereby reducing overall production cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Productivity

If the metal powder composition is optimized to enhance densification during sintering, then additional treatments can be eliminated, but the composition complexity increases

Engineering Contradiction:
Improveproduction efficiencyVSAvoidcomposition complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention applies local quality by adding specific elements (Ti, Nb, V) in precisely controlled small amounts (0.01-0.5 mass% each) to the Fe-based metal powder. This targeted, localized addition of alloying elements provides the necessary densification effect without requiring complex overall composition changes, thereby simplifying the manufacturing process while improving productivity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention manages composition complexity by making controlled parameter changes within specific ranges rather than arbitrary additions. By defining precise compositional parameters (Ti: 0.01-0.5 mass%, Nb: 0.01-0.5 mass%, V: 0.01-0.5 mass%), the invention achieves enhanced densification while maintaining compositional control, eliminating the need for complex additional treatments and thereby improving productivity.

Inventive Principle:
Principle #35Parameter changes

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 composition allows for the production of high-density sintered bodies with improved mechanical properties and corrosion resistance, eliminating the need for additional treatments like HIP, thereby reducing costs and increasing efficiency.

Implementation Method 1

an atomic diffusion phenomenon occurs among particles of the metal powder, whereby the molded body is gradually densified, resulting in sintering

Methodology Applied
Scientific EffectAtomic diffusion: Diffusion

Implementation Method 2

when one element selected from the group consisting of V, Y, Zr, Nb and Hf is defined as a first element, and one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta, and having a larger group number in the periodic table than that of the first element or having the same group number in the periodic table as that of the first element and a larger period number in the periodic table than that of the first element is defined as a second element

Methodology Applied
Scientific EffectCarbide formation: Chemical Bonding

Data Source

PatentEP3042975B1Metal powder for powder metallurgy, compound, granulated powder, and sintered body
Publication Date: 2019.12.18 SEIKO EPSON CORP

AI summary

A metal powder for powder metallurgy according to the invention contains Fe as a principal component, Cr in a proportion of 10 to 30 mass%, C in a proportion of 0.15 to 1.5 mass%, Si in a proportion of 0.3 to 1 mass%, and Mn and Ni in a total proportion of 0.05 to 1.6 mass%, wherein when one element selected from the group consisting of Ti, V, Y, Zr, Nb, Hf, and Ta is defined as a first element, and one element selected from the group and having a larger group number in the periodic table than that of the first element or having the same group number in the periodic table as that of the first element and a larger period number than that of the first element is defined as a second element, the first element is contained in a proportion of 0.01 to 0.5 mass%, and the second element is contained in a proportion of 0.01 to 0.5 mass%.