Cold Rolling Mill Strip Feed Paths for Induction Preheating
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Solution Overview
Problem
Discontinuous cold rolling mills face challenges in rolling brittle steel strips without risking strip cracks, particularly due to the lack of space for induction heating devices, which increases off-gauge length and scrap production.
Innovation Solution
Implementing an operating method where the second steel strip is heated using an induction heater, with the heating device positioned after the strip head has started moving towards the roll stand, allowing preheating without damaging the heating device, and arranging the heating device in the second path, which is longer than the first path, to ensure the steel strip is preheated before reaching the roll stand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an induction heating device is installed upstream of the first rolling stand to preheat steel strips, then the brittleness of high-silicon steel strips is reduced and strip cracking risk is lowered, but the installation space required is considerable and the dimensional length of cold-rolled steel strips increases
Solution Approach 1:
The patent applies preliminary action by heating the steel strip during the uncoiling process before it enters the rolling stand. The uncoiler is equipped with a heating device that preheats the strip while it is being uncoiled, ensuring the strip reaches the rolling stand at an elevated temperature without requiring additional installation space upstream of the rolling stand.
Solution Approach 2:
The patent employs dynamics by making the uncoiler movable rather than fixed. The uncoiler can be positioned at different locations relative to the rolling stand, allowing the system to adapt its configuration. This mobility enables the uncoiler to be placed closer to the rolling stand when heating is not required, thereby minimizing the dimensional length of the cold-rolled steel strip while still providing heating capability when needed.
2Reliability
If the uncoiler is positioned far from the rolling stand to accommodate induction heating, then heating of brittle steel strips is enabled, but the dimensional length of all cold-rolled steel strips increases and output decreases
Solution Approach 1:
The patent employs dynamics by making the uncoiler movable rather than fixed. The uncoiler can be positioned at different locations relative to the rolling stand, allowing the system to adapt its configuration. This mobility enables the uncoiler to be placed closer to the rolling stand when heating is not required, thereby minimizing the dimensional length of the cold-rolled steel strip while still providing heating capability when needed.
Solution Approach 2:
The patent applies parameter changes by varying the temperature of the steel strip through controlled heating during uncoiling. By adjusting the heating parameters of the uncoiler's heating device, the system can elevate the strip temperature to reduce brittleness only when necessary, without permanently altering the mill's physical layout or dimensional length.
3Temperature
If a heating device is installed in the first path to heat steel strips before rolling, then the brittleness of steel strips is reduced, but the installation space is consumed and the layout of continuous tandem mill is compromised
Solution Approach 1:
The patent applies universality by equipping the uncoiler with dual functionality: it serves both as the steel strip uncoiling device and as a heating device. The uncoiler incorporates a heating device that can heat steel strips during the uncoiling process, eliminating the need for a separate heating installation upstream of the rolling stand and preserving valuable installation space in the continuous tandem mill layout.
Solution Approach 2:
The patent merges the uncoiling function and the heating function into a single integrated unit. By combining these two functions in the uncoiler, the system achieves space efficiency while maintaining the ability to heat steel strips when needed, thus resolving the contradiction between temperature control and installation space constraints.
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 reduces the risk of strip tears in brittle steel strips, maintains a low off-gauge length, and allows for reliable rolling of steel strips without prior heating, while protecting the heating device from damage.
Implementation Method 1
the second steel strip is heated during its feeding to the rolling stand, with the second path being longer than the first... a heating device is arranged in the second path by means of which the second steel strip can be heated
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A first steel strip and a second steel strip (7) are rolled in succession in at least one roll stand (1) of a cold rolling mill. A rolling pause, in which no steel strip is rolled, is provided between the rolling of the first and the second steel strip (7). The first steel strip is fed over a first path starting from a first pay-off reel (2), and the second steel strip (7) is fed over a second path starting from the first pay-off reel (2), or from a second pay-off reel different from the first pay-off reel (2). The first steel strip is not heated as it is fed to the rolling mill (1), whereas, by contrast, the second steel strip (7) is heated. The second path is longer than the first path.