Two-Stage Heat Treatment Device for Metal Quenching

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Solution Overview

Problem

Existing heat treatment methods, such as air/water quenching, result in limited cooling gradients, leading to inhomogeneities and dimensional accuracy issues in metal processing, and pose a risk of corrosion.

Innovation Solution

A two-stage conditioning device for generating or transporting a fluid stream, comprising a heat exchanger for initial temperature reduction and an admixing device for further cooling by injecting a liquid medium, allowing for controlled and increased cooling gradients without changing the fluid's physical state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If air/water quenching is used, then cooling capability is improved, but cooling gradient uniformity deteriorates and corrosion risk increases

Engineering Contradiction:
Improvecooling capabilityVSAvoidcooling gradient uniformity
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The quenching process is segmented into two distinct stages: first air cooling to achieve initial temperature reduction, then water cooling to achieve final quenching. This segmentation allows each cooling medium to be applied optimally - air provides uniform initial cooling without the corrosion risks of water, while water delivers the intense cooling needed for final hardening, thus resolving the contradiction between cooling capability and uniformity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Air cooling is applied as a preliminary action before water quenching. By first reducing the temperature gradient through air cooling, the workpiece is prepared for subsequent water quenching in a controlled manner, preventing thermal shock and ensuring more uniform cooling gradients throughout the quenching process

Inventive Principle:
Principle #10Preliminary action

2Temperature

If water cooling is applied directly, then cooling gradient is improved, but water accumulation in undercuts occurs

Engineering Contradiction:
Improvecooling gradientVSAvoidwater accumulation
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The cooling process is divided into air cooling phase and water quenching phase. The air cooling phase initially reduces temperature without risking water accumulation in undercuts. Only after this preliminary cooling does water quenching begin, and even then, the two-stage approach controls water application to minimize accumulation while maintaining high cooling gradients in critical areas

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Air cooling serves as a preliminary action that removes excess heat before water application. This preliminary heat removal reduces the thermal load on the workpiece, allowing subsequent water quenching to achieve high cooling gradients without requiring excessive water application that would cause accumulation in undercuts

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If single-stage cooling is used, then device complexity is reduced, but cooling gradient control deteriorates

Engineering Contradiction:
Improvecooling system simplicityVSAvoidcooling gradient control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The cooling system is segmented into two distinct operational stages with different cooling media. This segmentation, while increasing device complexity slightly, provides precise control over cooling gradients by allowing air cooling for uniform initial temperature reduction and water cooling for intense final quenching, thereby achieving superior cooling gradient control that outweighs the added complexity

Inventive Principle:
Principle #1Segmentation

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 highly controllable and enhanced cooling gradients, improving mechanical properties like yield strength and tensile strength, while preventing water retention and ensuring consistent cooling performance.

Implementation Method 1

a first stage is based on heat transfer between the fluid flow and a coolant

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

a second stage is based on a change of state of the coolant, which extracts heat from the fluid flow

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

the enthalpy of vaporization is to be used to cool the fluid flow

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Implementation Method 4

the metal or workpiece is in particular a metal or workpiece made of aluminum or an aluminum alloy, wherein the workpiece or the material/metal is, for example, quenched

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3491154B1Heat treatment device
Publication Date: 2024.02.07 BAYERISCHE MOTOREN WERKE AG
  • EP3491154B1 patent drawingFigure 1

AI summary

The invention relates to a heat treatment device, in particular for quenching metals with a fluid stream, comprising a device for producing or transporting a fluid flow, and comprising a conditioning device, wherein the conditioning device is designed at least in two stages and in such a manner that the temperature of the fluid flow can be lowered in at least two stages.