Finish Rolling Mill Cleaning Nozzles for Hot Strip Surface Quality
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Solution Overview
Problem
The surface quality of hot strips produced by hot rolling is problematic, particularly for thin and ultra-thin strips, leading to increased energy use and production costs when high surface quality is required, as existing methods fail to effectively improve surface quality without significant energy input.
Innovation Solution
A finishing rolling train with cooling nozzles that spray a liquid cooling medium on the outer surfaces of work rolls and cleaning nozzles to remove scale and dust from the exit table, combined with a lifting roller to prevent contact between the hot strip and the exit table, ensuring the hot strip is not contaminated and maintaining high surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cold rolling is used to produce high surface quality parts, then surface quality is improved, but energy consumption increases significantly
Solution Approach 1:
The invention applies preliminary cooling and cleaning actions during the hot rolling process itself. Cooling nozzles are positioned to cool the work rolls before the strip enters, and cleaning nozzles remove scale and dust from the run-out table before the strip contacts it. This preliminary preparation prevents surface defects without requiring subsequent cold rolling, thus resolving the contradiction between surface quality and energy consumption.
2Duration of action of stationary object
If cooling nozzles are used to cool work rolls, then service life is extended, but hot strip may be contaminated by cooling medium
Solution Approach 1:
The invention introduces wipers as intermediary elements positioned between the cooling nozzles and the hot strip. These wipers physically block the cooling medium from contacting the strip while still allowing the cooling nozzles to cool the work rolls effectively. This intermediary solution resolves the contradiction between extending work roll service life through cooling and preventing strip contamination.
Solution Approach 2:
The cooling system is designed with localized cooling zones where cooling nozzles are positioned to cool only specific areas of the work rolls. The wipers are strategically placed to block cooling medium only in areas where strip contact might occur. This local differentiation allows effective cooling while preventing contamination, resolving the contradiction between service life extension and contamination prevention.
3Ease of manufacture
If thin hot strip is produced by hot rolling, then production cost is reduced, but surface quality becomes problematic
Solution Approach 1:
The invention applies preliminary cleaning actions during hot rolling by positioning cleaning nozzles to remove scale and dust from the run-out table before thin hot strip contacts it. This preliminary prevention of surface defects allows thin strip to be produced by cost-effective hot rolling while maintaining acceptable surface quality, resolving the contradiction between production cost and surface quality.
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 solution enhances the surface quality of hot strips by preventing contamination and ensuring a clean production process, allowing for the use of thin hot strips in applications with high surface quality demands without significantly increasing energy input.
Implementation Method 1
at least one outlet-side region of the outer surface of the lower work roll of the last rolling 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 outer surface
Implementation Method 2
the cooling medium is kept away from the hot strip by at least one wiper which is arranged vertically between the cooling nozzles and the hot strip
Implementation Method 3
at least one cleaning nozzle is provided for cleaning the upper side of the run-out table with a liquid or gaseous medium, so that scale and/or rolling dust are removed at least from the upper side of the run-out table
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a finishing rolling mill (7) for finishing hot-rolled strip (11). The object of the invention is to modify an existing finishing rolling mill in such a way that the surface quality of the produced hot-rolled strip (11) is improved without significantly increasing the energy consumption during production. This should enable the produced thin hot-rolled strip (11) to be used even for applications with high surface quality requirements. This object is achieved by a cleaning nozzle (17) that cleans the top of the discharge table (15), removing scale (Z) and/or rolling dust from the discharge table (15).