Slab Rolling Inversion for Width Wedge Removal
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Solution Overview
Problem
Achieving a uniform rectangular shape with constant width and thickness in rolled stock produced from ingot casting is challenging due to the conical mold shape, leading to thickness and width wedges that are difficult to remove using conventional vertical roll stands, resulting in uneven deformation and 'dogbone' formation.
Innovation Solution
A two-stage rolling process where the slab is rotated 90° after the first pass to invert the wedge shape, allowing for a diverging course in the second pass, enabling a fully automatic, high-precision setting of geometry without vertical roll stands, using a rolling train with horizontally aligned rolls and dynamically adjustable roll gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If vertical roll stands are used to reduce slab width, then width reduction is achieved, but material spreading occurs causing dogbone formation and uneven deformation
Solution Approach 1:
The patent inverts the conventional approach by using horizontal roll stands instead of vertical ones, and by inverting the wedge shape through controlled reverse curvature rolling. This inversion allows the material to be compressed in a way that prevents spreading and dogbone formation while achieving uniform width reduction.
Solution Approach 2:
The patent changes the rolling parameters by introducing reverse curvature in the roll gap and controlling the rolling force distribution along the slab length. This parameter change transforms the deformation pattern from uneven (with dogbones) to uniform, while maintaining effective width reduction.
2Shape
If stronger vertical stands are used to achieve complete width wedge removal, then width control improves, but device complexity and cost increase
Solution Approach 1:
Instead of increasing the strength of vertical stands to remove the width wedge, the patent inverts the approach by using horizontal stands with controlled reverse curvature rolling. This inversion achieves complete width wedge removal through a different mechanism that does not require excessive stand strength.
Solution Approach 2:
The patent replaces the conventional vertical rolling mechanics with a horizontal rolling system that uses reverse curvature. This substitution achieves the same width control objective with different mechanical principles, reducing the need for overly strong and complex stand structures.
3Manufacturing precision
If conventional rolling methods are used, then simple equipment is required, but the ability to achieve precise rectangular shape with uniform width is limited
Solution Approach 1:
The patent achieves precise rectangular shape control by changing the rolling parameters - specifically introducing reverse curvature in the roll gap and controlling the rolling force distribution. These parameter changes enable high-precision shape control while using relatively simple horizontal roll stands rather than complex vertical stands.
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 ensures a uniform width and thickness distribution, avoiding the formation of 'dogbones and achieving a precise cuboid shape with reduced material spreading, allowing for efficient production of rectangular sheets without the need for vertical roll stands.
Implementation Method 1
During a first rolling pass sequence, two opposite side surfaces of the rolling stock are rolled in a first direction in such a way that at the end of the first rolling pass sequence, all cross-sectional surfaces of the rolling stock that are oriented transversely to the rolling direction have the same area
Implementation Method 2
the rolling stock is fed into a nip between the work rolls of the rolling mills
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a novel method for rolling a rolled stock (2) produced in an ingot casting process, known as a slab, in a rolling train (13), wherein, before the rolling, the rolled stock (2) has the form of a truncated pyramid with a base area (4), a top area (6) and four side areas (8a, 8b, 10a, 10b), in which method: during a first rolling pass sequence, two opposite side areas (10a, 10b) of the rolled stock (2) are rolled in a first direction (R1) in such a way that, at the end of the first rolling pass sequence, all of the cross-sectional areas (4, 6) of the rolled stock (2) that are oriented transversely in relation to the rolling direction have the same surface area, the rolled stock (2) is turned, in particular through 90°, and, during a second rolling pass sequence, the same two opposite side areas (10a, 10b) of the rolled stock (2) are rolled in a second direction (R2), transversely in relation to the first direction (R1). The redistribution of the material of the rolled stock (2) that results from the form of the rolled stock (2) after the first rolling pass sequence makes it possible for the desired geometry to be set fully automatically with high precision, in particular without the use of vertical rolling stands.