Thermomechanical Rolling With Online Martensite Detection
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Solution Overview
Problem
Existing thermomechanical rolling processes for producing high-strength structural steels often result in unstable cooling processes leading to the sudden formation of martensitic microstructures in the surface regions, which negatively impact ductility properties.
Innovation Solution
A system and method incorporating a microstructure sensor device to detect martensitic microstructures during the rolling process, allowing for real-time adjustments of process parameters to maintain a consistent microstructure and prevent martensite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thermomechanical rolling processes are used to produce high-strength structural steels, then strength values are improved, but the cooling process becomes unstable leading to sudden formation of martensitic microstructures that negatively impact ductility
Solution Approach 1:
The patent employs a microstructure sensor device that continuously monitors the steel product during the rolling and cooling process to detect martensitic microstructure formation. This real-time feedback enables immediate adjustment of cooling parameters to prevent excessive martensite formation, thereby maintaining ductility while preserving strength gains from thermomechanical rolling.
Solution Approach 2:
The patent dynamically adjusts cooling parameters (temperature, cooling rate) based on real-time microstructure detection to control the phase transformation process. By changing these parameters in response to detected martensite formation, the process maintains the desired balance between strength and ductility.
2Reliability
If the cooling process is accelerated to prevent martensite formation, then ductility is improved, but the process time increases and productivity decreases
Solution Approach 1:
The microstructure sensor provides continuous monitoring that enables precise control of the cooling process. Instead of using a uniformly slow cooling rate throughout, the system accelerates cooling only when and where martensite formation is detected, and maintains faster cooling elsewhere, thereby preserving productivity while ensuring ductility.
Solution Approach 2:
The cooling process is made dynamic and adaptive rather than static. The cooling rate is continuously adjusted based on real-time microstructure feedback, allowing the system to optimize between speed and quality control throughout the rolling and cooling process.
3Manufacturing precision
If real-time microstructure detection is implemented, then quality consistency is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical microstructure analysis methods with a sensor-based detection system that uses physical or chemical sensing principles. This substitution enables real-time detection without the complexity of traditional metallographic preparation and analysis methods.
Solution Approach 2:
The microstructure sensor device is integrated directly into the rolling line, allowing the process to self-monitor and self-adjust without requiring separate offline quality control steps. This integration minimizes additional complexity while achieving continuous quality monitoring.
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 system ensures the production of wire and rod-shaped steels with a virtually martensite-free microstructure, enhancing ductility and mechanical properties while reducing scrap rates due to timely detection and correction of cooling issues.
Implementation Method 1
the sudden formation of undetected martensitic microstructures in the surface regions of the wire and/or bar-shaped structural steels
Implementation Method 2
a first cooling device arranged between the first and second rolling mills; a second cooling device arranged between the second rolling mill and the first thermomechanical sizing block; a third cooling device arranged between the first thermomechanical sizing block and the cooling bed
Data Source
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AI summary
The present application relates to a system (1) and a method for the thermomechanical rolling of long semifinished steel products (2), comprising a first rolling device (5); a second rolling device (7), arranged downstream of the first rolling device (5) in the transporting direction; optionally a first cooling device (6), arranged between the first and second rolling devices (5, 7); a first thermomechanical sizing block (11), arranged downstream of the second rolling device (7) in the transporting direction; a second cooling device (9), arranged between the second rolling device (7) and the first thermomechanical sizing block (11, 11.1); a cooling-bed, ring-laying and/or coil-winding device (16), arranged downstream of the first thermomechanical sizing block (11) in the transporting direction; a third cooling device (14), arranged between the first thermomechanical sizing block (11) and the cooling-bed, ring-laying and/or coil-winding device (16); and also a structure-sensor device (17), which is arranged between the first thermomechanical sizing block (11) and the cooling-bed, ring-laying and/or coil-winding device (16) and can be used for determining directly in the ongoing process a martensitic structure, in particular a proportion of martensite in percent by area (% by area), in the thermomechanically rolled long semifinished steel product or in the steel product (3) in the form of a wire or bar.