Reinventing Heat-Treating

Get ready to reconsider process strategies about the heat-treating of metals -- things like brazing, carburizing, hardening and sintering. A new approach, based on microwave-absorbing plasma, potentially changes all the rules, reports the aptly named Disruptive Technologies Group of Dana Corp., Toledo, Ohio. The plasma is generated and sustained at atmospheric pressure.

Implications of the process, called AtmoPlas, begin with low capital equipment expenditures (traditional furnaces aren't needed). In addition, Dana cites energy efficiency. The technology almost instantaneously heats the plasma, delivering up to 1,200 degrees Celsius with no upper temperature limit known, the company says. And unlike traditional furnaces, no idling is required, signaling the potential of reducing operating costs as much as 30%.

In addition to enabling shorter cycle times, the approach offers new operational versatility. For example, one system could perform different processes in the same workstation in sequence. One possibility: sintering then carburizing. Creative implementations could involve heating-to-go where small, portable heat-treating units could support flexible manufacturing concepts.

The use of plasma is the performance key to Dana's AtmoPlas technology. The plasma efficiently transmits heat to the workpiece without the need for a vacuum chamber. Traditionally, microwaves have not been used for metallurgical heat treatment because metals reflect the energy with arcing potentially damaging the system. With AtmoPlas, microwave-absorbing plasma surrounds the part to be heated. As the plasma absorbs the energy, the temperature rises and rapidly heats the part.

"While we expect the AtmoPlas technology to boost operating efficiency in our metal-treating operations, we're equally excited to demonstrate its value to other manufacturers and research organizations," says Dana chairman and CEO Michael J. Burns. "The potential of this proprietary process is far-reaching in industry." The next step is to show that the technology's value extends far beyond heat treating, says Dana's Heinz Eilks, executive vice president, business development and technology.

Future applications of technology could include treating vehicle exhaust emission, generating hydrogen and creating carbon nanostructures for use in the electronic and medical fields.

Applying the technology vehicle emissions control could make diesel engines more competitive, adds Rochester Hills, Mich.-based Satyendra Kumar, Dana's director-R&D, Core Microwave Technologies.