Precision rolled specialty alloy strip must meet a range of very high quality standards to satisfy the escalating requirements of those today who make largely high-technology, value-added parts and components from the mill product.

While discriminating parts manufacturers know exactly what they need for their individual operations, they generally have to rely on the strip producer to find a way to meet their special needs. However, parts makers can benefit from a better understanding of the control mechanisms that are key to getting desired results.

Many quality controls and features, for example, are provided by the highly engineered new equipment and processes utilized in the new Carpenter specialty alloy strip mill. Following are some of them, with a brief definition of what each means to the parts producer.

Gage Controls - hold the strip thickness to within better-than ASTM limits. This control allows the parts producer to improve productivity, hold closer dimensional tolerances, reduce costs and save weight. An automated machine that stacks laminations, for instance, will run without interruption if the strip, and every coil of strip, meets the close tolerance fit requirements. Otherwise it will jam.

The right strip thickness and tolerances permit more consistent tooling setup, eliminating the need for costly tool change and machine downtime. These same controls also improve product uniformity and enhance fabrication properties, such as those needed for deep drawing.

Shape Control - allows the parts maker to hold the strip perfectly flat during stamping, and produce parts that remain flat after fabrication. When the finished part holds the shape required, there is less need for rework, and less chance of the production equipment jamming in operation.

Surface Finish - the new strip grinder and associated handling equipment are designed to eliminate surface defects such as scratches, rub marks, slivers, gouges and even "dings".

The benefits are both cosmetic and functional. A fine scratch, for instance, cannot be tolerated because it can provide a leak path in a critical glass-to-metal seal. Furthermore, surface defects can trap dirt, and cause non-uniform coatings apt to peal away.

Edge and Width Control - the precision slitter with CNC controls and inflatable arbor control the edge quality and the width tolerance. Both are key to potential fabrication economics. Reducing or eliminating burrs on the edge, for example, can minimize the chance of a loose coil coming apart in a stamping machine, and causing catastrophic damage.

With its new equipment and processes, Carpenter expects to meet or exceed industry standards for strip width tolerances. Tighter tolerances and more uniform width, along with better camber control, can result in both a better coil package and fewer reject parts.

The tighter tolerances now provided, in fact, could open the door to scrapless die technology. This next-higher level of productivity will allow manufacturers to stamp an "E" and similar straight edges to the very edge of the rolled strip, eliminating the loss of material that is currently scrapped.

Premium Melting - nothing more dramatically underscores the high-end, high-quality nature of parts made from specialty alloy strip than the fact that nearly half of the Carpenter-manufactured strip used for those parts is currently premium vacuum melted. What's more, Carpenter expects the demand for still more vacuum melted alloys to trend vigorously higher into the forseeable future.