Fe-Based Alloy Powder Composition for Crack-Resistant 3D Molded Parts
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Solution Overview
Problem
Existing Fe-based alloy powders for additive manufacturing fail to adequately balance hardness, heat conductivity, and crack resistance, with existing parameters like 'A' in Patent Literature 3 not reliably preventing cracks, and other parameters focusing on hardness and conductivity without addressing crack formation effectively.
Innovation Solution
An Fe-based alloy powder with specific elemental compositions and carbon equivalent (Ceq) limits, along with controlled Ms point, to suppress crack formation while maintaining high hardness and conductivity, produced through rapid melting and solidification processes like 3D additive manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Fe-based alloy powder with high carbon equivalent is used to increase hardness, then hardness of shaped article is improved, but crack formation increases
Solution Approach 1:
The invention changes the chemical composition parameters of the Fe-based alloy powder, specifically controlling carbon content to 0.30-0.50 mass%, Si to 0.10-0.40 mass%, and limiting carbon equivalent Ceq to 0.95 mass% or less. This parameter optimization resolves the contradiction by achieving adequate hardness (42.0 HRC or more after quenching and tempering) while suppressing crack formation during additive manufacturing.
Solution Approach 2:
The invention creates a composite alloy system combining Fe with specific amounts of C, Si, Mn, Cr, Ni, Mo, V, and Al elements. This composite material approach allows the alloy to achieve both high hardness through controlled carbon content and crack resistance through the synergistic effects of multiple alloying elements, particularly Si and Mn which refine grain structure and reduce brittleness.
2Strength
If Fe-based alloy powder with high carbon content is used to increase hardness, then quenching and tempering hardness is improved, but heat conductivity decreases
Solution Approach 1:
The invention optimizes the carbon content parameter to a specific range of 0.30-0.50 mass%, which is higher than conventional powders to achieve 42.0 HRC or more hardness after quenching and tempering, yet controlled below 0.50 mass% to prevent excessive carbon from severely degrading heat conductivity. This balanced parameter selection resolves the contradiction between hardness and heat conductivity.
Solution Approach 2:
The invention applies local quality by concentrating carbon content specifically in the matrix structure to achieve hardness, while controlling overall distribution to maintain heat conductivity. The alloying elements create localized hard phases (carbides) while the base matrix retains good thermal properties, achieving both high hardness (42.0 HRC or more) and adequate heat conductivity (40.0 W/m·K or more).
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 ensures shaped articles with enhanced toughness, suppressing cracks, achieving quenching and tempering hardness of 42.0 HRC and heat conductivity of 40.0 W/m·K, suitable for applications like hot-working dies.
Implementation Method 1
irradiating the Fe-based alloy powder according to any one of aspects 1 to 4 with an energy beam to melt and solidify the Fe-based alloy powder, thereby producing a shaped article
Data Source
AI summary
An Fe-based alloy powder that can suppress cracks of a shaped article is provided. The Fe-based alloy powder contains, in terms of mass %: 0.30≤C≤0.50; 0<Si≤0.40; 0<Mn≤0.40; 0.85≤Cr≤1.75; 0<Ni≤0.40; 0.70≤Mo≤1.20; 0<V≤0.60; 0<Al≤0.10; and 0≤W≤0.40%, the balance consisting of Fe and unavoidable impurities. The Fe-based alloy powder comprises a Ceq, which is a carbon equivalent determined by converting an influence of elements other than carbon contained in the Fe-based alloy powder into a carbon amount, of 0.95% or less.