Controlling Variable Thickness in Rolled Steel Cooling System Applications

In today’s guest post, Emerson’s Eric Kuebler, a metals & mining industry manager on the Fisher valve team, describes how a steel mill solved the challenge to produce steel sheets of varying thickness and receive ongoing operational savings.

Water is used throughout all mining and ore processing plants and is an important player in all applications. In a previous post, Is Water Management a Core Competency for Successful Mining, Emerson’s Ron Pozarski discussed how this commodity must be managed under better scrutiny as water supply management has become a main focus globally.

To ensure their water management was up to par, a fully integrated steel mill took a look at their water pressure and flow control measures and realized they had a problem.

This steel mill, located in Michigan, produces more than 3.6 million tons per year of hot rolled sheet. The mill had used on/off butterfly valves to control the water pressure in the Roll Coolant system. These valves controlled the flow of water through pumps and spray nozzles to cool the molten steel during the rolling process. This is a critical application as this process determines the thickness of the rolled sheet.

However, due to changing market requirements, this organization had to produce sheets of steel with varying thicknesses. This required more precise control from their coolant water system, and the original butterfly valves were not suitable. Without the appropriate control, they would not remain competitive in the market.

The plant staff chose Fisher Control-Disk valves, which allow for the controllability of a segmented ball in the package of a butterfly valve. The unique disk design provides a modified equal percent characteristic, and expands the traditional butterfly control range between 10 and 70 degrees of opening—beyond the controllability or rangeability of current butterfly valve technology.

After the installing nine of these valves in the mill’s water coolant system processing lines the steel mill immediately saw improved control. The additional throttling control allowed the mill to reduce both its water usage and the amount of steel wasted (or blanched) by too much water. These nine installations are expected to reduce the mill’s water usage up to 50% and enable them to eliminate one pump. The reduction of one pump alone has a long-term benefit that could save the mill about $1M per year or more.

Nine Fisher Control-Disk valves on water service saved one mill over $1M per year. If your application requires controllability and rangeability beyond what your butterfly valves can provide, you might have a similar, strong economic case to switch.

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