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ANNEALING

Managing Anneal Cycles for More Profit - 21809 ManagingAnnealing Cycles ManagingAnnealing Cycles

A suite of process control modules can be used in asingle-stack or multi-stack shop, using any atmospheric gas, to anneal sheet, wire, and nonferrous products. The modules are ideal for new starts, or can be retrofitted easily into an existing configuration.

BY WALLACE D. HUSKONEN, contributing editor

for More Profit for More Profit

I

n October, when California Steel In-dustries reported the best quarterly results in the company’s 20-year his-tory, the announcement was noted with considerable satisfaction at Entec Inc., a software company specializing in control systems for annealing steel.That’s because when the Fontana,CA-based steel processor decided in 1998 to replace its annealing facili- ties, it assigned the turnkey project toRad-Con Inc. At that time, Entec wasworking closely with Rad-Con and supplied the process-management system for the entire annealing opera- tion. Since then, Rad-Con has pur- chased Entec and incorporated it as an operating division.The CSI project was a two-phase ef-fort. The first phase involved installing eight new bases in a coil-storage area near a strip-cleaning line. These were installed in such a way that CSI was able to use its existing furnaces in two separate shops, so that no production capacity was lost. The new equipment then replaced the 310,000-tons/year ca- pacity of the existing furnaces, which were removed, and 12 more bases in- stalled in the second phase. When the installation was complete, CSI had new annealing capacity totaling 360,000 tons/year for producing commercial- and drawing-quality steels.

A suite of programs

Annealing shops need dependableand timely control of all aspects of the process. According to McDonald, CAPS Suite includes an array of modules and models that can be integrated to con- trol the various elements of the process into one seamless package. They in- clude inventory management, alarm recognition, process trending, base op- eration, data archiving, and reporting.CAPS is specifically designed for theneeds and requirements of the anneal-ing operation. It can be used in a singlestack or multi-stack shop, using any at- mospheric gas, for sheet, wire, and non- ferrous products. CAPS can be adopted as part of a new shop start-up or it can be retrofitted easily into an existing configuration. Above all, CAPS is a supervisory con-trol system for the anneal shop. ItsShop Overview screen displays the cur- rent shop activity, including critical in- formation like status, control tempera- ture, and event time for each base.Data is entered into screens usingpull down menus and check boxes. Temperature tables and graphs for current and completed runs are viewed in CAPS to monitor the process efficiently and effectively. And, the operator is notified of alarm conditions that require attention.CAPS with optional H.60.SC inte-grates Level 1 HMI functions for equip- ment control and operation to provideone seamless Level 1+2 package. Thisapproach streamlines communications and provides a single user interface for all shop operations. Connecting CAPS to the plant-wideInventory Management System allows the operator to view and edit coils available to anneal. Scheduling infor- mation, such as priority, ship week, or anneal late-start date, can be down- loaded for use in building loads. This in- formation can be used manually or by the Stacking Model option. CAPS allows designated operators,or metallurgists, to enter cycles, or recipes, into the system. Multiple steps with different temperatures, gas-flow rates, ramp rates, and hold times can be entered for each cycle. The operatorchooses the cycle to run for each load,dependent upon the coils in the load. Level 1 communication provides auto- matic download of setpoints to the PLC or controller at the beginning and dur- ing the cycle.

Process management

Michael McDonald, Rad-Con vicepresident and general manager of the Entec division, recalls, “We were adapt- ing our systems to existing furnaces, sort of an after-market ‘add on.’ With the CSI job, our system was included with the installation. It was something of a change.”Over the years, Entec has developedproprietary models to maximize the ef- fectiveness of gas flows and heating and cooling phases, as well as monitorcoil conditions like cleanliness. Its foundation is a relational database ac- cessible from the operators’ PC through Entec’s Computerized Anneal- ing Process System (CAPS). The models take into account thecoils’ hot and cold spots during anneal- ing to modify cycle parameters asneeded to achieve the desired result in the most efficient way. As McDonaldpoints out, “The models are more ana- lytical than empirical, so they adapt very effectively to the circumstances.”The CSI installation also featured aninventory-management function that determines how to mix and arrange the coils in a charge, based on information from the plant data network. Thus, cer- tain coils can be rushed or delayed, based on delivery needs. The annealing operation can combine or recompose charges based on order fulfillment de- mands, and mix or separate coils ac- cording to compatibility for an anneal-ing cycle.
Process models maximize gas flow and heating andcooling phases for California Steel’s recentlyinstalled annealing operation.

Stacking and heating

Determining the “best” coils to beannealed in a particular load is a com-
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