Hot Strip Exit Table Cleaning to Prevent Finish Rolling Surface Defects
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Solution Overview
Problem
The surface quality of hot strip produced by hot rolling is problematic, necessitating additional cold rolling for high-quality applications, which increases energy use and production costs.
Innovation Solution
A finishing train for hot strip rolling that includes cooling nozzles to cool the roll stands and cleaning nozzles to remove scale and rolling dust, combined with a lifting roller to prevent contact between the hot strip and the exit table, ensuring high surface quality without significantly increasing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If hot rolling is used to produce thin hot strip, then production cost and energy use are reduced, but surface quality becomes problematic
Solution Approach 1:
The invention applies preliminary cleaning action by equipping the exit table with cleaning nozzles that remove scale and rolling dust before the hot strip leaves the rolling mill. This preliminary cleaning prevents surface defects from forming in the first place, eliminating the need for subsequent cold rolling and associated energy consumption while maintaining high surface quality
Solution Approach 2:
The invention introduces an intermediary lifting roller between the exit table and the hot strip. This lifting roller raises the hot strip slightly above the exit table surface, creating a gap that prevents direct contact between the strip and any remaining contaminants on the table. This intermediary mechanism protects the strip surface without requiring additional energy-intensive processing steps
2Manufacturing precision
If cold rolling is used to improve surface quality, then surface quality is improved, but energy use and production costs increase sharply
Solution Approach 1:
The invention performs preliminary cleaning of the exit table with cleaning nozzles before the hot strip exits the rolling mill. By removing scale and rolling dust in advance, the surface quality is improved at the hot rolling stage itself, making subsequent cold rolling unnecessary and avoiding the associated energy consumption and production costs
Solution Approach 2:
The invention extracts the essential function of surface quality improvement from the traditional cold rolling process and relocates it to the hot rolling exit stage. Through cleaning nozzles and a lifting roller, the surface quality enhancement is achieved during hot rolling, allowing the hot strip to be used directly for high-quality applications without the energy-intensive cold rolling step
3Duration of action of stationary object
If cooling nozzles are used to cool the working rolls, then service life and roll contour stability are improved, but risk of cooling the hot strip increases
Solution Approach 1:
The invention applies local quality control by directing cooling nozzles to cool only specific regions of the working rolls (particularly the exit-side regions) while using a lifting roller to maintain a gap between the hot strip and the cooled roll surfaces. This localized cooling approach achieves the desired roll temperature control for extended service life and contour stability without causing unwanted cooling of the hot strip itself
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
Improves the surface quality of hot strip, allowing its direct use in high-demand applications while reducing energy consumption and production costs.
Implementation Method 1
at least one exit-side region of the lateral surface of the lower working roll of the last roll stand in the transport direction is cooled by a plurality of cooling nozzles arranged below a pass line, and the cooling nozzles spray a liquid cooling medium onto the lateral surface
Implementation Method 2
at least one cleaning nozzle is provided for cleaning the upper side of the exit table with a liquid or gaseous medium, thus ensuring that scale and/or rolling dust are/is removed at least from the upper side of the exit table
Implementation Method 3
at least one lifting roller, which is arranged in the width direction of the hot strip, is arranged between the last roll stand and a cooling section for cooling the finish-rolled hot strip, and the lifting roller lifts the hot strip in the vertical direction above the pass line
Data Source
AI summary
The invention relates to a finishing train for finish rolling hot strip. It is the object of the invention to modify an existing finishing train in such a way that the surface quality of the hot strip produced is improved without, however, significantly increasing the use of energy during production. This is intended to enable the thin hot strip produced to be used even for applications with high demands on surface quality. This object is achieved by a cleaning nozzle which cleans the upper side of the exit table, thus ensuring that scale and/or rolling dust are/is removed from the exit table.