Additive-Manufactured Metal Part Densification by Local Heat and Load

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Solution Overview

Problem

Additive manufacturing of metal components often results in porosity, leading to fatigue issues such as flaking and pitting, which can cause premature failure, and existing treatments like Hot Isostatic Pressing are time-consuming, complex, and limited in size capability.

Innovation Solution

A method involving localized heating of metal components using a controllable heating device, followed by immediate application of a mechanical load to plastically deform and densify the material, reducing internal voids and porosity, and improving microstructure and fatigue resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Hot Isostatic Pressing is used to reduce porosity and improve physical properties, then the metal component's density and workability are improved, but the process becomes time-consuming, complex and expensive

Engineering Contradiction:

Improvephysical propertiesVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The treatment process is segmented into two distinct sequential steps: first heating the metal component to form a softened region, then applying mechanical load to plastically deform the softened region. This segmentation eliminates the need for complex high-pressure containment vessels and isostatic gas pressure systems required by HIP, while achieving similar porosity reduction through localized thermal-mechanical processing

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention replaces the complex mechanical isostatic pressing system with a simpler thermal-mechanical approach. Instead of applying 50-300 MPa isostatic gas pressure throughout the component, the method uses localized heating followed by targeted mechanical loading, substituting the complex pressure application system with more straightforward thermal and mechanical operations

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If Hot Isostatic Pressing is used to treat metal components, then porosity is reduced, but the process is not feasible for large metal components such as bearing rings with diameter greater than one metre

Engineering Contradiction:

Improveporosity reductionVSAvoidcomponent size

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The invention applies local quality by heating only specific regions of the metal component to form softened regions, rather than treating the entire component uniformly. This localized approach allows treatment of large components like bearing rings with diameters greater than one metre, as the heating and mechanical loading can be applied sequentially to different sections without requiring the entire component to fit within a high-pressure containment vessel

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If additive manufacturing is used to produce metal components, then complex geometries can be created, but porosity is introduced that adversely affects fatigue properties

Engineering Contradiction:

Improvegeometry complexityVSAvoidfatigue resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The invention applies preliminary action by heating the metal component before applying mechanical load, creating a softened region that is more receptive to deformation. This preliminary thermal treatment enables subsequent mechanical loading to effectively close porosity and refine grain structure, thereby improving fatigue resistance while preserving the complex geometries enabled by additive manufacturing

Inventive Principle:

Principle #10Preliminary action

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

This method enhances fatigue resistance, surface finish, and physical properties while being less costly and complex than Hot Isostatic Pressing, with no size restrictions, and can be integrated into existing manufacturing processes.

Implementation Method 1

heating the at least one part of the metal component, i.e. the at least one part of the metal component that has been produced by additive manufacturing, to form at least one softened region

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

applying a mechanical load to the at least one softened region, i.e. to the same region that has just been heated, to plastically deform the metal in the at least one softened region

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Implementation Method 3

The application of the heat and mechanical load reduces or eliminates internal voids, cracks and porosity in the at least one part of the metal component that has been produced by additive manufacturing through a combination of plastic deformation, creep and diffusion bonding

Methodology Applied

Scientific EffectDiffusion bonding: Diffusion Welding

Implementation Method 4

Methodology Applied

Scientific EffectCreep: Creep

Data Source

PatentUS20240238870A1Method & computer program product

Publication Date: 2024.07.18 AB SKF SKF PATENT DEPARTMENT

AI summary

A method is for treating at least one part of a metal component that is at least partly produced by additive manufacturing. The method comprises the steps of heating the at least one part of the metal component to form at least one softened region, and applying a mechanical load to the at least one softened region to plastically deform the metal in the at least one softened region.