The new equipment installed in the new Carpenter specialty alloy strip mill is state-of-the-art, largely customized to enhance operating results and product quality. Every unit was selected and placed in line on the basis of an intensive study to assess what strip users said they needed to fulfill their near and long-term future growth requirements. Investigating teams also benchmarked their findings against other producers of similar strip products.

Frohling 20-high cold rolling mill

This mill, with an automatic, online shape measurement and control system, offers two important benefits. It increases rolling capacity, and ensures good strip shape and flatness. Thickness is reduced as the strip passes between two work rolls, each of which are backed up by nine more rolls (thus the term "20-high"). The mill cold rolls strip at high speed, with precision, in thicknesses between 0.150" and 0.008".

Strip speed is measured by a non-contact TSI laser system that is more accurate than conventional contact speed gauges, and not subject, like contact gauges, to slipping and marking the strip.

A special Vollmer shape control system allows control of strip shape by an operator or computer. It offers five different means of controlling shape - (a) A split housing design with direct cylinder gap adjustment allows the upper cluster of rolls to tilt to conform with any incoming thickness profile. With this design, the system can maintain the proper profile for wedge and crown shapes. Twenty four measurement zones across the strip are scanned to provide automatic feedback and finite control.

(b) Three intermediate roll bending controls permit superior shape control, while minimizing parabolic defects. This feature reduces the need for roll changing, which means more mill uptime. (c) Two intermediate roll shifting devices help to control strip shape. It is especially helpful in minimizing strip "waviness" and wavy edges.

(d) Work roll zone cooling with mineral oil helps to control asymmetrical defects and produce a superior surface. Use of vacuum coolant removal, in place of wipers, eliminates scratches and rub marks. (e) Vollmer contact gauges provide continuous, precision gauge control over the full width of the strip from end to end of every coil.

An automatic General Electric gage control system takes readings from the Vollmer gage measuring system and a TSI laser speed measuring system, which monitors strip entry/exit speeds and entry/exit thickness, to control exit thickness of the strip. The GE drive control system and the gauge control system are in seamless communication; which translates into improved efficiency and ease in trouble shooting.

Finally, the Frohling mill will enable Carpenter to produce coils of up to 8,000 lbs., and roll high tensile strength precipitation hardenable (PH) grades in widths up to 16 inches.

Frohling mill management system

This mill management system, customized by Carpenter, helps to minimize variation in the cold rolled strip. All of the rolling schedules are entered daily and stored in a common data base. The system is designed to collect every bit of information needed to facilitate efficient process control.

Input parameters are based on incoming coil characteristics. With data gathered, the system predicts the schedule required for each coil rolled. All process data is stored to check the accuracy of each prediction, allowing repeated schedules to be optimized with experience.

Hill Acme wet strip grinder

The new Hill Acme wet strip grinder prepares the strip surface for further finish processing. This new unit permits the simultaneous grinding of both sides of the strip. This improvement alone increases productivity.

With a new inline cleaning capability, the strip feeds off the grinder into a cleaning line where it is water flushed under pressure, rinsed and dried. A stand alone cleaning process is eliminated.

The coolant used when grinding wet acts as a lubricant, improving grinding belt life. Wet grinding also allows use of finer grit belts which, in turn, produce better strip surface quality. As a result, the mill can now cold roll products that require an extremely fine finish - such as photo-etch quality strip for circuit board applications.

In addition, the new wet grinder has given the mill the capability of increasing maximum strip thickness from 0.187" to 0.265".

Ebner bell annealing furnace

This new 30-ton capacity furnace will be used to heat treat semi-finished strip products in an atmosphere that will not affect the strip surface. The furnace will increase capacity, improve product quality and consistency, and eliminate strip scratching.

The unit includes one heating bell, two bases, one cooling bell and two inner covers. Two annealing bases with the furnace allow the operator to prepare the second while the other is in the annealing cycle.

Loads of up to 60,000 lbs. of semi-finished strip can be annealed in this furnace. It will anneal multiple coils of one material, or multiple coils of various materials together, depending on the heating cycle. It also can perform specialized thermal cycles for specific properties.

Excellent temperature uniformity is provided by high convection of hydrogen gas atmosphere. This furnace environment will improve coil hardness uniformity.

Ebner vertical bright-strand annealing furnaces

These Ebner furnaces consist of three vertical annealing lines that operate at higher productivity levels than conventional horizontal furnaces. They are designed to continuously process - without interruption for coil loading and unloading - the bright annealing of specialty alloy strip.

The vertical design allows the strip to hang under low tension and benefit from rapid temperature change. Properties of the finished strip are more uniform because accumulators keep the strip from stopping in the furnace.

One line anneals heavy gauge strip from 0.050" to 0.187" thick, while the other two lines process thin gauge product from 0.006" to 0.060" thick. Coils are welded end-to-end for continuous annealing.

Edge guide controls steer the strip to minimize edge damage and produce better coil "wrap", a condition that gives the customer a tighter, easy-to-handle package. Tension controls prevent stretching. Improved cleaning equipment - an alkali degreasing section followed by a rinsing section - cleans oil, residue and dirt from the strip before it enters the furnace.

The vertical annealing design offers other quality improvements, as well. The absence of carbon rolls to support the strip eliminates scratching, thus producing a higher quality surface. Similarly, a roller exit seal prevents scratching and rub marks. Since the strip is not stopped in the furnace, the annealed strip has better, more uniform coil hardness.

As with the Bell furnace and the wet strip grinder, the vertical annealing furnaces also employ an automated data archiving system that enhances process control. A temperature readout is provided automatically with the vertical annealing furnaces. This reading allows constant monitoring of process conditions.

Ungerer stretch bend leveler

The Ungerer stretch bend leveler has been designed to flatten strip thinner than 0.050" and document flatness quality throughout the entire length of a coil. It uses a shape measurement roll with five measurement zones across the width of the strip to precisely control shape.

This shape measurement roll provides information for operator control or direct computer control of the stretch/bend process. By continuously monitoring results, the equipment can achieve, then maintain, a high level of quality.

The new stretch bend leveler replaces what used to be an art form with a scientific method of obtaining high quality strip. It will significantly reduce the need and cost of re-working or re-flattening strip.

Frohling thin gauge precision slitter

The Frohling precision slitter has been designed to slit strip less than 0.015" thick. It is expected to improve strip product quality, substantially expand capacity and increase slitting efficiency.

This new slitter will operate at speeds up to 1,500 fpm. It will slit up to 35 strands simultaneously, compared with a maximum of about 16 with the slitter previously used.

CNC control of the arbor position provides precision accuracy of both the upper and lower slitting knives. Accuracy of the knife position reduces both burring and twisting of the strip.

A turnstile with a four-position knife setup minimizes the time required to change knives. In summary, the new slitter provides better slit edge quality and tighter control of width tolerances, while extending the service life of the cutting knives.