Titanium Nitriding via Electromagnetic Induction Heating
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Solution Overview
Problem
Current nitriding processes for titanium parts result in case depths of 0.005 inches or less, which are insufficient to withstand larger applied loads and prevent surface and sub-surface stresses, leading to issues like galling, scoring, and fretting, and undesired mechanical property changes in titanium parts used in applications such as gears and bearings.
Innovation Solution
A method and apparatus that uses an electromagnetic field to heat a portion of the titanium part to 60-99% of its melting point in a nitrogen-containing gas environment, creating a hardened case with a depth of 0.005 inches or greater, while minimizing changes to the mechanical properties below the selected depth, using a chamber with a gas delivery system and induction coil system to control the heating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional nitriding processes are used on titanium parts, then a case layer is formed to improve surface hardness, but the case depth is limited to 0.005 inches or less which is insufficient to withstand larger applied loads
Solution Approach 1:
The patent applies parameter changes by heating the titanium part to elevated temperatures (60-99% of melting point) using electromagnetic induction heating, which enables nitrogen diffusion to achieve case depths of 0.005 inches or greater. This temperature parameter change transforms the conventional nitriding process to overcome the depth limitation while maintaining surface hardness improvement.
Solution Approach 2:
The patent replaces conventional thermal field methods with electromagnetic induction heating to achieve the required heating for deep nitriding. This substitution enables precise control of heating parameters and achieves the desired case depth without compromising the underlying mechanical properties of the titanium part.
2Strength
If the case depth is increased to withstand larger loads, then the part can carry heavier loads, but undesired changes occur in the mechanical properties of the underlying material
Solution Approach 1:
The patent applies local quality by creating a gradient in nitrogen concentration and temperature distribution during the nitriding process. The electromagnetic induction heating and controlled nitrogen exposure create a case layer with desired hardness at the surface while maintaining the original mechanical properties of the underlying titanium material, achieving different properties at different depths of the same component.
3Ease of manufacture
If conventional nitriding processes are used, then the process is simple and cost-effective, but the case depth is insufficient to prevent surface and sub-surface stresses leading to galling, scoring, and fretting
Solution Approach 1:
The patent replaces conventional thermal field nitriding with electromagnetic induction heating, which provides more precise and controlled heating. This substitution enables achieving sufficient case depth (0.005 inches or greater) to prevent surface and sub-surface stresses and related failures, while maintaining process efficiency and avoiding the complexity of multiple conventional treatment steps.
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 achieves a hardened case on titanium parts that can withstand increased loads and reduce friction and stress-related issues, extending the life of components like gears and bearings and reducing maintenance costs by forming a deeper, more effective surface layer without compromising the mechanical properties of the underlying material.
Implementation Method 1
An electromagnetic field may be generated in the chamber with the gas. The electromagnetic field may heat a portion of the metal in the positioned part to a temperature from about 60 percent to about 99 percent of a melting point of the metal.
Implementation Method 2
using a chamber with a gas delivery system and induction coil system to control the heating process
Implementation Method 3
With nitriding, nitrogen may be introduced into a portion of the titanium part through, for example, without limitation, diffusion. This introduction of nitrogen into the titanium part may produce a layer on the surface of the titanium part comprising, without limitation, titanium nitrides.
Data Source
AI summary
A method and apparatus for manufacturing a part. The part may be positioned in a chamber. The part may be comprised of a metal and may be a positioned part. A gas containing nitrogen may be sent into the chamber. An electromagnetic field may be generated in the chamber with the gas. The electromagnetic field may heat a portion of the metal in the positioned part to a temperature from about 60 percent to about 99 percent of the melting point of the metal such that the portion of the metal has a desired hardness. The portion of the metal may extend from a surface of the positioned part to a selected depth from the surface.