Ferritic Hot Strip Surface Heating for Low-Energy Descaling
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Solution Overview
Problem
The energy-intensive process of producing ferritic hot strips in composite casting-rolling plants results in high energy consumption due to the need for intensive heating and cooling, compromising energy efficiency while maintaining good metallurgical properties and surface quality.
Innovation Solution
The process involves using inductive surface heating modules to heat the broad sides of the intermediate strip to a surface temperature of ≥1000 °C with alternating current frequencies ≥20 kHz, followed by descaling and finish rolling without additional cooling, allowing the last rolling pass to occur in the ferritic temperature range, thereby reducing energy input and maintaining high surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the intermediate strip is heated to high temperature (≥1070 °C) for descaling, then good surface quality is achieved, but energy consumption increases significantly
Solution Approach 1:
The patent applies local quality by heating only the surface layers of the intermediate strip to high temperature (≥1000°C) for descaling, while the core temperature remains lower (775-900°C). This is achieved through inductive surface heating modules that concentrate thermal energy at the strip surfaces, enabling effective oxide scale removal without the need to heat the entire strip cross-section to high temperatures, thus reducing overall energy consumption while maintaining good surface quality.
2Manufacturing precision
If intensive cooling is applied after descaling to achieve ferritic temperature range, then metallurgical properties are improved, but energy consumption increases
Solution Approach 1:
The patent inverts the conventional approach by avoiding intensive cooling after descaling. Instead of heating the entire strip to high temperature and then cooling it down to achieve ferritic range, the method directly heats only the surface to descaling temperature while maintaining the core at ferritic temperature (775-900°C) throughout the process, eliminating the need for energy-intensive cooling operations while still achieving the desired metallurgical properties.
3Stability of the object's composition
If the entire intermediate strip is heated to high temperature, then uniform heating is achieved, but energy consumption and thermal stress increase
Solution Approach 1:
The patent applies local quality by creating a deliberate temperature gradient through the strip thickness - the surface layers are heated to high temperature (≥1000°C) for descaling while the core remains at lower ferritic temperature (775-900°C). This localized heating approach, achieved through inductive surface heating modules, eliminates the need to heat the entire strip uniformly, significantly reducing energy consumption while avoiding excessive thermal stresses that would result from heating the massive strip cross-section to high temperature.
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 method significantly reduces energy consumption by only heating the surface layers of the intermediate strip, ensuring thorough descaling and maintaining good metallurgical properties and surface quality, while achieving a high coiling temperature without additional heating or cooling.
Implementation Method 1
heating the broad sides of the intermediate strip by one or preferably more inductive surface heating modules to a surface temperature ≥ 1000 °C, preferably ≥ 1050 °C, wherein the surface heating module is operated with an alternating current with a first frequency f1 and the following applies to the first frequency f1: f1 ≥ 20 kHz, preferably f1 ≥ 50 kHz, particularly preferably f1 ≥ 100 kHz
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to the energy-efficient production of a ferritic hot-rolled strip (6) in a casting-rolling composite plant (1). The object of the invention is to modify the known methods for producing a ferritic hot-rolled strip (6) in a casting-rolling composite plant (1) in such a way that the ferritic hot-rolled strip (6) can be produced in a significantly more energy-efficient manner, while still exhibiting good metallurgical properties and a good surface quality. This object is achieved by a method according to claim 1.