Cooling Track Control for High-Carbon Steel Enthalpy

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Solution Overview

Problem

Existing methods for cooling steel in rolling mills, particularly those with high carbon content, face challenges in achieving precise material properties, leading to inconsistent final products and reduced production flexibility due to ambiguous temperature specifications and multiple coolant quantity solutions.

Innovation Solution

A control device for the cooling section that receives initial enthalpy and phase proportion information, determines a coolant quantity profile to achieve a final enthalpy value, independent of the final temperature, ensuring desired material properties by actively and passively cooling the steel based on predetermined time segments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a temperature profile is specified for cooling high-carbon steel, then the cooling process can be controlled, but the material properties become inconsistent due to phase transformation heat effects

Engineering Contradiction:
Improvematerial properties consistencyVSAvoidcooling process reliability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent changes the control parameter from temperature to enthalpy. By specifying an enthalpy profile instead of a temperature profile, the cooling process accounts for phase transformation heat effects automatically. The enthalpy-based control method determines coolant quantity based on the difference between initial and final enthalpy values, ensuring consistent material properties regardless of temperature fluctuations during phase transformations.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple coolant quantity solutions exist for a given final temperature, then flexibility in cooling strategy is available, but manufacturing precision decreases due to ambiguous specifications

Engineering Contradiction:
Improvecooling strategy flexibilityVSAvoidmaterial properties precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces feedback control by continuously monitoring the actual enthalpy value during cooling and comparing it with the target enthalpy profile. The control device adjusts the coolant quantity in real-time based on the difference between actual and target enthalpy, ensuring precise achievement of the desired final state. This feedback mechanism eliminates the ambiguity of multiple solutions by dynamically selecting the optimal coolant quantity at each moment.

Inventive Principle:
Principle #23Feedback

3Productivity

If fully automatic operation is implemented for high-carbon steel cooling, then productivity increases, but manufacturing precision decreases due to difficulty in achieving desired material properties

Engineering Contradiction:
Improveautomatic operation efficiencyVSAvoidmaterial properties accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces manual operator judgment with an automated control system that uses enthalpy-based calculations. The control device automatically determines the coolant quantity profile by calculating the difference between initial and final enthalpy values, eliminating the need for human intervention while ensuring precise material properties. This substitution of manual control with automated enthalpy-based control achieves both high productivity and manufacturing precision.

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

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 approach allows for precise control of material properties, ensuring the desired final enthalpy and temperature are reached, regardless of the steel's speed through the cooling section, thereby improving the reliability and consistency of the cooling process for high-carbon steel production.

Implementation Method 1

Because of the heat of transformation that occurs during the phase transformation of austenite into ferrite and cementite

Methodology Applied
Scientific EffectPhase transformation: Phase Change

Implementation Method 2

a coolant is applied to the steel as it passes through the cooling line. As a result, the course of cooling over time of the steel passing through the cooling section is adjusted

Methodology Applied
Scientific EffectHeat extraction: Heat Exchanger

Data Source

PatentEP2244850B1Method of operation for a cooling track for cooling a rolling product, with cooling to an end enthalpy value uncoupled from temperature
Publication Date: 2013.01.30 SIEMENS AG
  • EP2244850B1 patent drawingFigure 1
  • EP2244850B1 patent drawingFigure 2~4
  • EP2244850B1 patent drawingFigure 3

AI summary

A control device (8) for a cooling track (1) for cooling a rolling product (5) accepts at least partially characteristic information (TA) for a starting enthalpy value. The control device (8) determines a refrigerant volume progression (K) such that a heat volume corresponding to the difference between the starting enthalpy value (EA) and a prespecified end enthalpy value (EE) is removed from a rolling product segment (12) of the rolling product (5) during the movement of said rolling product through the cooling track (1). The control device (8) determines the refrigerant volume progression (K) independently of whether a prespecified end temperature value (TE) assigned to the end enthalpy value (EE) is reached at the end of application of refrigerant (6) to the rolling product (5). The control device (8) applies refrigerant (6) to the rolling product segment (12) during its passage through the cooling track (1) according to the determined refrigerant volume progression (K).