Rolled Steel Strength Control via Cooling and Straightening

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Solution Overview

Problem

Existing procedures struggle to consistently achieve target tensile strength and stretching limit/replacement line in rolled goods, especially when the chemical composition of steel alloys deviates from the target composition.

Innovation Solution

The procedure involves calculating model-resistant and model stretching limit values, then adjusting at least two nominal operating parameters: cooling temperature and immersion depth of a guideline, to minimize deviations from target values, thereby enhancing reproducibility and ease of implementation in existing systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If only one nominal operating parameter of the rolling mill is adjusted to compensate for alloy composition deviations, then alloying costs are saved, but the ability to simultaneously achieve both target tensile strength and target yield strength is limited

Engineering Contradiction:
Improveachievement of target mechanical propertiesVSAvoidcontrol over multiple mechanical parameters
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies parameter changes by adjusting multiple nominal operating parameters (cooling stop temperature, immersion depth of straightening rollers) to compensate for alloy composition deviations and achieve both target tensile strength and target yield strength simultaneously

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the control of mechanical properties by addressing tensile strength and yield strength through different operating parameters - cooling stop temperature primarily affects tensile strength while immersion depth of straightening rollers primarily affects yield strength, allowing independent optimization of both parameters

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If multiple operating parameters are adjusted to achieve both target tensile strength and target yield strength, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvedeviation from target mechanical propertiesVSAvoidnumber of adjusted operating parameters
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the operating parameters adjustable and adaptable - the cooling stop temperature and immersion depth of straightening rollers can be dynamically adjusted based on the actual alloy composition to achieve the desired mechanical properties, providing flexibility without permanent system modification

Inventive Principle:
Principle #15Dynamics

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 reliably reduces deviations in tensile strength and stretching limit/replacement line, improving reproducibility and making it easier to manage in existing roller road systems, while maintaining product quality and consistency.

Implementation Method 1

at least one cooling device (2b) for accelerated cooling of the rolled stock (4) after finish rolling by the at least one rolling stand (2a)

Methodology Applied
Scientific EffectAccelerated cooling: Cooling

Implementation Method 2

at least one roller straightener (3) arranged downstream of the hot rolling mill (2)

Methodology Applied
Scientific EffectMechanical straightening: Mechanical Force

Data Source

PatentEP4523807A1Method for reducing a deviation from a target tensile strength and a target yield strength/replacement limit of rolled goods
Publication Date: 2025.03.19 VOESTALPINE GROBBLECH GMBH
  • EP4523807A1 patent drawingFigure 1
  • EP4523807A1 patent drawingFigure 2~3
  • EP4523807A1 patent drawingFigure 4~5

AI summary

Methods for reducing deviations from a target tensile strength (Rm_target) and a target yield strength/equivalent yield strength (Re_target/Rp0.2_target, Rt0.5_target etc.) of rolled products (4), in particular steel sheets, produced by a plant (1) comprising at least one hot rolling mill (2) and at least one roller straightening machine (3) downstream of the hot rolling mill (2), and of single- or multi-layer rolled slabs or rolled blocks of a common steel grade, the respective steel alloy of which deviates in at least one alloying element from the target chemical composition of this steel grade due to the manufacturing process, are shown.