Asymmetric Cooling of Coiled Metal Strip Ends
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Solution Overview
Problem
High-tensile metal strips with high elastic residual stresses tend to spontaneously open or unroll during coiling due to uneven cooling and stress distribution, particularly in hot-rolling processes, leading to instability in the coil structure.
Innovation Solution
A method and coiling installation where the end portion of the metal strip is subjected to asymmetric impingement with a cooling medium, causing a stress profile that results in curvature, with the length of impingement being greater than half the outermost coiling but less than the full coil diameter, to prevent self-acting opening by ensuring the end portion bears pressure on the next inner coiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-tensile metal strip is coiled with conventional symmetric cooling, then the coiling process can proceed, but the coil spontaneously opens or unrolls due to elastic residual stresses
Solution Approach 1:
The patent applies asymmetric cooling by directing the cooling medium primarily at one side of the metal strip end portion during coiling. This creates an asymmetric temperature distribution and stress profile that generates a bending moment, causing the end portion to curve and bear against the next inner coiling, thereby preventing spontaneous opening or unrolling of the coil.
Solution Approach 2:
The patent changes the temperature parameter asymmetrically across the strip width during coiling. By cooling one side more than the other, it creates a temperature gradient that induces plastic deformation and curvature in the end portion, transforming the stress state to stabilize the coil structure.
2Reliability
If the end portion is cooled asymmetrically to prevent spontaneous opening, then coil stability is improved, but the cooling process becomes more complex
Solution Approach 1:
The patent applies cooling locally and asymmetrically to the end portion of the metal strip rather than uniformly across the entire strip. The cooling medium is directed specifically at one side of the end portion, creating the necessary asymmetric stress profile with minimal additional system complexity.
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 reliably prevents spontaneous opening or unrolling of the coil by ensuring the end portion is plastically deformed to a curvature radius that stabilizes the coil, effectively addressing the issue of residual stresses and maintaining coil integrity.
Implementation Method 1
an asymmetric impingement on the sides of the end portion with a cooling medium prior to and/or during the coiling of the end portion causes a stress profile to be incorporated in the end portion of the metal strip across the thickness of the strip in the case of the temperature of the end portion still being sufficiently high
Implementation Method 2
A plastic deformation of an end portion of the metal strip is caused such that the end portion in the uninfluenced state is curved at a radius of curvature
Data Source
AI summary
For a rolled metal strip, in particular a steel strip; a drive roller unit deflects the metal strip from a first transportation direction to a second transportation direction, and the strip is then fed to a coiler. The metal strip is coiled in the coiler to form a coil having a coil diameter. Plastic deformation of an end portion of the metal strip is caused such that the end portion in its uninfluenced state is curved at a curvature radius. The plastic deformation of the end portion (8) is at least partially caused by an asymmetric impingement with a cooling medium (21) on the sides of the end portion (8). The impingement of the end portion (8) with the cooling medium (21) is performed across a length of the end portion (8) that is longer than half the outermost coiling of the coil (6) but smaller than the outermost coiling of the coil (6).