Mandrelless Coil Box Friction Control for Lighter Coils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing coil boxes in hot-rolling mills are limited by minimum coil weight requirements, leading to insufficient friction during unwinding, pauses in strip feeding, and non-uniform temperature profiles, which restrict throughput and quality of rolled material.
Innovation Solution
A mandrelless coil box with a vertically adjustable hold-down assembly and combination of active and passive transfer methods, along with temperature control devices, to increase friction, reduce residence time, and achieve uniform temperature profiles, allowing for lighter coil handling and higher throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a coil box is used with lighter coils, then the application range and throughput are improved, but insufficient friction between unwinding rolls and strip prevents proper unwinding
Solution Approach 1:
The hold-down assembly is made vertically adjustable and movable between active and inactive positions. During active transfer, the assembly is in the inactive position to allow passive transfer. During unwinding of lighter coils, the assembly is in the active position to provide necessary friction. This dynamic positioning resolves the contradiction by adapting the friction force to the operational requirements.
Solution Approach 2:
The hold-down force parameter is changed by moving the hold-down assembly between active and inactive positions. When active, the assembly increases the normal force between the hold-down rolls and the coil, thereby increasing friction. This parameter change allows lighter coils to be handled effectively without preventing proper unwinding of heavier coils when the assembly is inactive.
2Speed
If active transfer mechanism is used, then transfer speed is improved, but gaps in roller path cause coil damage during passive transfer
Solution Approach 1:
The hold-down assembly dynamically switches between active and inactive states based on the transfer mode. During active transfer at high speed, the assembly is inactive to avoid interference. During passive transfer, the assembly is active to prevent coil damage by maintaining contact and preventing bumping against abutments. This dynamic behavior resolves the contradiction between speed and reliability.
Solution Approach 2:
The hold-down assembly acts as an intermediary device that mediates between the active transfer mechanism and the coil. It provides a continuous contact path during passive transfer, preventing the coil from dropping into gaps and being damaged, while not interfering with the active transfer mechanism when it is in operation.
3Productivity
If residence time in upstream station is reduced, then throughput is improved, but temperature uniformity deteriorates
Solution Approach 1:
The hold-down force parameter is adjusted to optimize both throughput and temperature uniformity. By controlling the hold-down force, the system can maintain adequate friction for lighter coils while managing the residence time. The adjustable nature of the hold-down assembly allows optimization of the balance between throughput and temperature uniformity based on specific operational conditions.
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
Enables the handling of lighter coils with increased throughput and uniform temperature profiles, reducing radiant heat loss and improving strip quality, thereby expanding the coil box's application range and enhancing material processing efficiency.
Implementation Method 1
The hold-down assembly 1 increases the friction between the coil C and the rollers
Implementation Method 2
The strip inside the coil box loses heat by radiation and contact with the rollers
Implementation Method 3
The strip inside the coil box loses heat by radiation and contact with the rollers
Data Source
AI summary
The invention relates to a method for expanding the use of a coiling and uncoiling station (coilbox) located between the roughing train and the finishing train for rolled strip material in hot-rolling mills. The use of said coilbox is expanded by impinging the coil that is to be uncoiled with a pressing force (F) which acts in the direction of the roller table (4) and/or placing the coil in a depression of the roller table in order to process smaller coil weights in a spikeless coilbox, and/or by combining, in a chronological and weight-related manner, the active transfer and passive transfer of a coil from a first coiling station to a second coiling station in order to increase the throughput especially at average coil weights in a spikeless coilbox, and/or by supplying heat to the strip upstream or downstream of the spikeless coilbox and/or thermally insulating the strip or the coilbox in order to variably increase and homogenize the strip temperature. The invention further relates to a correspondingly equipped device for carrying out said method.