Cold Rolling Mill Conversion for Higher Capacity With Minimal Shutdown
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Solution Overview
Problem
Existing cold rolling mills face challenges in upgrading their capacity efficiently, particularly from single stand to twin stand or twin stand to tandem mills, due to high shutdown times and costs associated with conventional conversion methods.
Innovation Solution
A flexible conversion method that allows for the expansion of a twin stand mill into a tandem mill or PLTCM by utilizing existing foundations, installing additional rolling stands during normal production, and connecting them with a transfer means, reducing the need for extensive civil works and shutdown time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional conversion methods are used to upgrade from twin stand mill to tandem mill, then production capacity is increased, but shutdown time increases significantly (approximately two months)
Solution Approach 1:
The patent applies preliminary action by pre-preparing the assembly area and positioning the additional stand on the delivery side during normal operation. The civil works foundations are prepared in advance, and the assembly area is designated before shutdown, enabling rapid installation when the mill is stopped. This preliminary preparation significantly reduces the actual conversion time from two months to a much shorter period.
2Productivity
If conventional conversion methods are used to upgrade rolling mill capacity, then production capacity is increased, but conversion costs increase
Solution Approach 1:
The patent applies universality by designing the additional stand and its supporting infrastructure to serve multiple functions. The civil works foundations are designed to accommodate both the original mill and the additional stand. The assembly area serves as both a preparation zone and an installation platform. This multi-functional design reduces redundant construction and lowers overall conversion costs.
Solution Approach 2:
The conversion process is segmented into distinct phases: preparation during normal operation, installation during shutdown, and commissioning. The additional stand is designed as a separate, modular unit that can be manufactured and positioned independently before being integrated with the existing mill. This segmentation reduces complexity and enables parallel processing, lowering conversion costs.
3Ease of manufacture
If a twin stand mill configuration is used, then investment costs and operative costs are lower compared to tandem mill, but production capacity is limited
Solution Approach 1:
The patent applies dynamics by creating a hybrid configuration that allows the mill to operate in two modes: twin stand mode during normal operation and tandem mill mode during conversion. The additional stand is positioned on the delivery side and can be integrated into the existing production line. This dynamic approach enables the mill to maintain lower costs during operation while having the capability to expand capacity when needed.
Data Source
Figure 1
Figure 2a~2d
AI summary
A flexible conversion method of a reversible rolling mill (1) having at least one rolling stand (2) erected on first civil works foundations (6) and a first production capacity, into an upgraded rolling mill (1') having more than one rolling stand (2, 2') and a second production capacity, said second production capacity being higher than the first production capacity, wherein the upgraded rolling mill (1') is obtained at the end of the conversion by providing to it an exclusive delivery side corresponding to the entry side of the former reversible rolling mill (1) and an entry side located on the same side as the delivery side of the former reversible rolling mill (1), the entry tension reel (4) becoming after conversion a delivery tension reel only, so that the rolling operation is done in one pass only and the rolling mill is not reversible anymore.