Additive Manufacturing Powder for Die-Casting Dies with Oxide Coating

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Solution Overview

Problem

Existing die-casting die materials, such as tool steel SKD61, have limitations in forming complex water-cooling circuits and suffer from reduced thermal conductivity due to high silicon content, which affects cooling performance and machinability.

Innovation Solution

A powder for additive manufacturing with a specific composition (0.25<C<0.40, 0.001≤Si≤0.15, 0.30≤Mn≤0.45, 5.0≤Cr≤5.5, 1.0≤Mo≤1.5, 0.35≤V≤0.45, 0.01≤N≤0.05, 0.01≤O≤0.04, and optional elements) is used, which is coated with an oxide film to prevent aggregation and improve conveyance, allowing for the creation of non-linear cooling circuits with enhanced thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If tool steel for hot working (e.g., SKD61) is used for die-casting die, then high durability against heat check is achieved, but thermal conductivity is reduced due to high silicon content (0.9 mass%)

Engineering Contradiction:
Improvedurability against heat checkVSAvoidthermal conductivity
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the steel material by reducing silicon content to 0.15 mass% or less and adjusting other elements (C: 0.25-0.40, Mn: 0.30-0.45, Cr: 5.0-5.5, Mo: 1.0-1.5, V: 0.35-0.45) to achieve both high durability against heat check and high thermal conductivity. This resolves the contradiction by optimizing the compositional parameters rather than using conventional high-silicon tool steel.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If water-cooling circuit is formed by cutting, then simple linear circuits can be produced, but complex three-dimensional cooling circuits cannot be formed

Engineering Contradiction:
Improveease of forming water-cooling circuitVSAvoidcomplexity of cooling circuit shape
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical cutting method with additive manufacturing technology. The water-cooling circuit is formed by selectively melting and solidifying metal powder layers according to a three-dimensional model, enabling complex non-linear cooling circuits to be created directly without mechanical cutting. This substitution of manufacturing method resolves the limitation of conventional cutting techniques.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If metal powder is used for additive manufacturing, then complex three-dimensional shapes can be formed, but powder aggregation occurs making conveyance difficult

Engineering Contradiction:
Improveability to form complex shapesVSAvoidease of powder conveyance
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent optimizes the particle size parameters of the metal powder (average particle size: 10-50 μm, specific surface area: 0.1-1.0 m²/g) to prevent aggregation and improve conveyance. The controlled particle size distribution and surface characteristics enable smooth powder flow in the additive manufacturing process while maintaining the ability to form complex three-dimensional structures.

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 powder enables the production of die-casting die parts with improved thermal conductivity and reduced processing requirements, eliminating the need for quenching and preventing aggregation, while maintaining high machinability and heat resistance.

Implementation Method 1

the surface of the powder for additive manufacturing is coated with an oxide film

Methodology Applied
Scientific EffectOxide film formation: Oxidation

Implementation Method 2

irradiating the powder layer with an energy beam such as a laser beam or an electron beam to thereby locally melt and solidify the powder layer

Methodology Applied
Scientific EffectEnergy beam irradiation: Laser

Implementation Method 3

irradiating the powder layer with an energy beam such as a laser beam or an electron beam to thereby locally melt and solidify the powder layer

Methodology Applied
Scientific EffectLocal melting and solidification: Melting

Implementation Method 4

a water-cooling circuit internally so that molten metal press-fitted into the die can be solidified in a short time

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3753653B1Powder for additive manufacturing, and die-casting die part
Publication Date: 2022.01.19 DAIDO STEEL CO LTD

AI summary

The present invention relates to a powder for additive manufacturing, having a composition consisting of, in mass%: 0.25&lt;C&lt;0.40, 0.001≤Si≤0.15, 0.30≤Mn≤0.45, 5.0≤Cr≤5.5, 1.0≤Mo≤1.5, 0.35≤V≤0.45, 0.01≤N≤0.05, 0.01≤O≤0.04, and optionally, P&lt;0.10, Cu&lt;0.20, Ni&lt;0.20, A1&lt;0.05, Zr&lt;0.05, S&lt;0.20, Pb&lt;0.20, Bi&lt;0.20, Nb&lt;0.20, Ti&lt;0.20, B&lt;0.10, and Co&lt;0.20, with the balance being Fe and unavoidable impurities, in which a surface of the powder for additive manufacturing is coated with an oxide film, and the oxide film has a thickness of 3 nm or more and 30 nm or less.