Fe-Based Alloy Powder for High Heat Conductivity and Hardness
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Solution Overview
Problem
Conventional steel grades used in additive manufacturing, such as maraging steel and SKD61, have low heat conductivity, leading to decreased cooling efficiency and production cycle speed in applications like die-casting and hot stamping, and lack sufficient hardness and softening resistance for repeated high-temperature use.
Innovation Solution
An Fe-based alloy powder with specific composition ranges (0.20<C<0.60, Si<0.60, Mn<0.90, Cr<4.00, Ni<2.00, Mo<1.20, W<2.00, V<0.60, Al<0.10) is used, which, when processed through rapid melting and cooling methods, produces a shaped article with enhanced heat conductivity (27.0 W/m/K or more) and quenching and tempering hardness (41.0 HRC or more), suitable for hot work tools like molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional steel grades (maraging steel, SKD61) are used in additive manufacturing, then the material can be processed by metal additive manufacturing methods, but the heat conductivity is low (about 20 W/m/K), leading to decreased cooling efficiency and production cycle speed
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material by precisely controlling the content ranges of C, Si, Mn, Cr, Ni, Mo, W, V, and Al elements. This compositional parameter optimization enables the steel to achieve both high hardness (41 HRC or more after quenching and tempering) and high heat conductivity (27 W/m/K or more), resolving the contradiction between hardness and heat conductivity in additive manufactured steel molds
Solution Approach 2:
The invention creates a composite microstructure through controlled alloying, where multiple alloying elements work synergistically to form a complex microstructure that combines high hardness phases with high heat conductivity phases. The specific composition ranges create a balanced microstructure that achieves both mechanical strength and thermal performance
2Strength
If steel with high hardness is produced by conventional forging method, then the degree of hardness and heat conduction can be improved, but coarse carbides are easily formed which serve as point of origin for fatigue failure
Solution Approach 1:
The invention replaces the conventional mechanical forging process with metal additive manufacturing technology. This substitution allows for precise control of the solidification and cooling process, creating a fine-grained microstructure without the coarse carbide formation typical of forging. The layer-by-layer additive process enables homogeneous distribution of alloying elements and prevents carbide aggregation, achieving both high hardness and fatigue resistance
Solution Approach 2:
The invention changes the processing parameters from conventional forging to additive manufacturing parameters, including controlled layer thickness, laser power density, scanning speed, and inter-layer cooling time. These parameter changes enable the formation of fine carbides distributed uniformly throughout the microstructure, preventing the formation of coarse carbides that would initiate fatigue failure while maintaining high hardness
3Strength
If alloy elements are added to enhance hardness, then the degree of hardness can be improved, but heat conductivity decreases due to increased scattering frequencies of conductive electrons
Solution Approach 1:
The invention optimizes the concentration parameters of alloying elements by establishing specific content ranges for each element. This controlled alloying approach ensures that hardness-enhancing elements are present in sufficient quantities to achieve 41 HRC or more, while their total concentration is limited to minimize electron scattering. The balanced composition achieves the optimal trade-off between hardness and heat conductivity
Solution Approach 2:
The invention creates a multi-element alloy system where different elements contribute synergistically to the overall properties. The specific combination of alloying elements creates a composite microstructure where hardening phases and heat-conducting phases coexist, achieving both high hardness and acceptable heat conductivity through compositional design
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 resulting shaped articles exhibit improved heat conductivity, hardness, and softening resistance, enabling efficient cooling and prolonged high-temperature performance, making them suitable for hot work tools like molds with complex shapes.
Implementation Method 1
processed through rapid melting and cooling methods, produces a shaped article with enhanced heat conductivity (27.0 W/m/K or more) and quenching and tempering hardness (41.0 HRC or more)
Implementation Method 2
a portion irradiated with a laser beam or an electron beam, of a powder which has been spread, is molten and solidified
Implementation Method 3
a portion irradiated with a laser beam or an electron beam, of a powder which has been spread, is molten and solidified
Implementation Method 4
The shaped article according to any one of formulas (1) to (3), subjected to quenching and tempering treatment, has a heat conductivity of 27.0 W/m/K or more and a hardness of 41.0 HRC or more
Data Source
AI summary
Provided is a shaped article which can satisfy both high heat conducting properties and hardness (quenching and tempering hardness, and hardness after retention at a high temperature and softening). The shaped article produced from an Fe-based alloy powder, the Fe-based alloy powder consisting of, in mass %: 0.20<C<0.60; Si<0.60; Mn<0.90; Cr<4.00; Ni<2.00; Mo<1.20; W<2.00; V<0.60; Al<0.10; and the balance consisting of Fe and unavoidable impurities, wherein the shaped article satisfies the following formulae (1) to (3): (1) T1≥30.67; (2) T2>50.0; (3) PC<3.0.