Phosphors and Galvanneal Steel Cont.

ORNL Wins 1999 R&D 100 Award

Steve Allison (left), Wayne Manges, Tim McIntyre, Mike Cates and David Beshears are part of the team that developed the galvanneal temperature measurement system, which provides crucial on-line thermal process control information during the manufacture of rust-resistant, galvanneal steel used in automobiles.

Most automobiles manufactured today do not rust as quickly as older vehicles because galvanneal sheet steel is used in their construction. To save energy, reduce waste, and ensure a quality product, ORNL has developed a measurement system for the steel industry that allows control of the temperature when galvanneal steel forms.

The galvanneal process creates a protective layer on a steel sheet by dipping it in molten zinc and heating the coated sheet in a furnace to make the iron and zinc atoms form an alloy on the surface. The problem is that the metal surface temperature may vary in the furnace, making the product quality nonuniform.

ORNL's galvanneal temperature measurement system makes it possible to strictly control steel surface temperature, enabling the production of uniform, high-quality galvanneal steel. The system uses a computer; laser; light detector; optical fibers; and white phosphor powder, which is dusted on each steel sheet by a computerized phosphor-deposition device. The laser light excites the phosphors, which emit light for a short time, based on how hot they and the steel sheet are. Measurements of the time it takes for the light emissions to disappear are used by the computer to calculate the surface temperature of the galvanneal steel.

The real-time monitoring information is used by steel producers to determine whether furnace operation must be adjusted to maintain the correct temperature.

The system was developed by ORNL's Steve Allison, David Beshears, Mike Cates, Mitchell Childs, Wayne Manges, Tim McIntyre, and Marc Simpson (from the Engineering Technology and the Instrumentation and Controls divisions) in conjunction with the American Iron and Steel Institute (AISI), Bailey Engineers, and the National Steel Technical Center. This effort was supported by DOE's Office of Industrial Technology and AISI, a steel industry consortium that managed the project. (For more information, see the Review, Vol. 32, No. 1, 1999, pp.17-18.)

In 1998 the ORNL system was installed and successfully tested at Bethlehem Steel's facility in Burns Harbor, Indiana. The technology has been licensed to Bailey Engineers. The system was made part of a West Virginia steel manufacturer's production line.