Cold Rolling Temperature Control for Brittle High-Silicon Steel
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Solution Overview
Problem
Cold rolling of magnetic steel sheets with high silicon content faces challenges such as brittleness leading to strip cracks and unstable production conditions, due to temperature limitations and lubricant degradation, which affects the rolling process and downstream processing steps.
Innovation Solution
A method and rolling train that control the rolled stock temperature through predetermined upper and lower limits using open-loop or closed-loop control measures, including heating, cooling, lubrication, pass sequence distribution, and rolling speed, to maintain the temperature within specific ranges, reducing brittleness and improving production conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rolled-stock temperature is increased to reduce brittleness, then the brittleness of magnetic steel sheets is reduced, but the lubricant may crack and the rolled-stock temperature may exceed the recrystallization temperature
Solution Approach 1:
The rolled stock is heated to a run-in temperature before the first rolling pass to reduce brittleness in advance. This preliminary heating action allows the material to be more ductile during subsequent rolling operations without requiring excessive temperature increases during the rolling process itself, thereby avoiding lubricant degradation and recrystallization issues.
Solution Approach 2:
The invention applies multiple temperature control measures including heating the rolled stock to a run-in temperature before the first rolling pass, cooling the working rollers of rolling stands, and cooling the rolled stock between rolling passes. These parameter changes allow precise control of the rolled-stock temperature to maintain it within a specific range that reduces brittleness while preventing excessive temperature increase.
2Reliability
If the rolled-stock temperature is kept low for cold rolling, then the lubricant remains stable and the rolled stock remains ductile, but the forming resistance of the rolled stock increases
Solution Approach 1:
The rolled stock is heated to a run-in temperature before the first rolling pass to reduce forming resistance in advance. This preliminary heating action reduces the force required during subsequent rolling operations while maintaining the rolled-stock temperature within acceptable limits through controlled cooling measures during the rolling process.
Solution Approach 2:
The invention applies heating the rolled stock to a run-in temperature before the first rolling pass to reduce forming resistance, combined with cooling measures during rolling to maintain lubricant stability. This parameter change allows the system to achieve lower forming resistance while keeping the rolled-stock temperature within a specific range.
3Strength
If the rolled-stock temperature is increased, then the brittleness is reduced, but the wear of mill equipment increases and the flatness of the rolled stock deteriorates
Solution Approach 1:
The invention applies cooling the working rollers of rolling stands and cooling the rolled stock between rolling passes to maintain the rolled-stock temperature within a specific range. This parameter control prevents excessive temperature increase that would cause equipment wear and flatness deterioration while still allowing sufficient temperature increase to reduce brittleness through controlled heating before rolling.
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 reduces the risk of strip cracks, enhances production stability, allows flexible further processing of cold-rolled stock, minimizes energy consumption, and protects mill equipment by maintaining the rolled stock temperature within optimal limits during cold rolling.
Implementation Method 1
heating the rolled stock to a run-in temperature before the first rolling pass
Implementation Method 2
cooling the working rollers of at least one rolling stand by applying a roller coolant to the working rollers
Implementation Method 3
cooling the rolled stock between at least two rolling passes which follow one another by applying a rolled-stock coolant to the rolled stock
Implementation Method 4
a lubricant is usually applied to the working rollers of the rolling stands and/or to the rolled stock in order to reduce friction between the rolled stock and the working rollers
Data Source
AI summary
A method for cold rolling rolled stock (2) in a mill train (1) with multiple roll stands (3 to 7). An upper limit temperature and/or a lower limit temperature is provided for a rolled stock temperature of the rolled stock (2) for at least one rolling pass, and the rolled stock temperature is controlled and/or regulated by at least one control or regulating measure such that during the at least one rolling pass, the rolled stock temperature does not exceed the upper limit temperature specified for the rolling pass and/or the rolled stock temperature does not fall below the lower limit temperature specified for the rolling pass.