Segmented Strip Steel Heating for Uniform Rapid Annealing
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Solution Overview
Problem
Existing annealing processes for cold-rolled strip steel face challenges in temperature control precision, energy efficiency, and surface defect reduction due to fluctuations in heating conditions and the need for complex control schemes, especially when using high-frequency inductive heating methods.
Innovation Solution
The proposed solution involves dividing the heating zone into four sections with a combination of radiant and inductive heating, using two induction heaters in series, and employing multi-wavelength thermometers for precise temperature control, allowing for improved temperature uniformity and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a single rapid inductive heating section is used to heat strip steel from room temperature to near Curie temperature, then heating speed increases, but temperature uniformity in width direction deteriorates and production efficiency is restricted
Solution Approach 1:
The heating section is divided into multiple independent heating zones (first rapid heating section, second rapid heating section, and third heating section) along the strip steel travel direction. Each zone has its own heating capabilities, allowing staged temperature increase and better temperature distribution across the strip width, resolving the contradiction between heating speed and temperature uniformity.
2Productivity
If the plate temperature at outlet of first heating section is increased to 500°C or more for thick strip steel or fast unit speed, then heating efficiency improves, but the temperature of strip steel at outlet of second heating section cannot reach Curie temperature and temperature uniformity deteriorates
Solution Approach 1:
The system employs dynamic temperature control where the first and second rapid heating sections can independently adjust their heating intensities based on real-time temperature feedback. This allows the outlet temperature of the first heating section to be increased for high productivity cases while the second heating section dynamically compensates to ensure the final outlet temperature reaches Curie temperature with proper uniformity.
Solution Approach 2:
Temperature detection devices are installed at various positions including the outlet of each heating section. The detected temperature signals are fed back to control systems that adjust the heating power of subsequent sections in real-time, enabling precise control of outlet temperatures even when production efficiency requirements demand higher initial heating rates.
3Manufacturing precision
If complex control schemes are adopted to stabilize plate temperature at outlet of second heating section using high-frequency inductive heating, then temperature control precision improves, but device complexity and control technology requirements increase
Solution Approach 1:
Instead of using a complex control scheme for a single large heating zone, the system segments the heating function into multiple simpler heating sections along the strip travel direction. Each section has its own temperature detection and control, which simplifies the control logic for each individual section while achieving overall precise temperature control at the final outlet.
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 enhances production efficiency, reduces energy consumption per ton of steel, and improves the magnetic properties and surface quality of finished products by maintaining precise temperature control and reducing surface defects.
Implementation Method 1
the heating section can be divided into three sections, wherein the first heating section is a radiant heating section using gas heating or electric heating to heat the strip steel to 50° C. below Curie temperature Tc; the second heating section is a high frequency inductive heating section heating the strip steel to a temperature in a range between 30° C. below Tc and 5° C. below Tc
Implementation Method 2
the first heating section is a radiant heating section using gas heating or electric heating
Data Source
AI summary
An apparatus and a method for rapidly heating cold-rolled strip steel (10). The apparatus for rapidly heating cold-rolled strip steel (10) comprises a heating zone, a soaking zone, and a cooling zone, and the heating zone is sequentially divided into a first heating section (1), a second heating section (2), a third heating section (3), and a fourth heating section (4) along a moving direction of the strip steel (10) to be heated, the first heating section (1) and the fourth heating section (4) being radiant heating sections, and the second heating section (2) and the third heating section (3) being inductive heating sections. The method for rapidly heating cold-rolled strip steel (10) uses the apparatus for rapidly heating cold-rolled strip steel (10) to heat the strip steel (10).