Most vacuum furnaces currently active in the heat-treating world incorporate some form of, or combination of, graphite-felt insulation, with either a foil or board internal facing in the furnace hot-zone construction. The graphite felt used in high-temperature furnaces is either PAN-based or Rayon-based.

Many papers have been written on the subject of vacuum furnace leaks, how to detect them and how to find them.

The overall furnace design and volume determines the required throughput of the pumping system and the ultimate vacuum expected.

The objective of this paper is to highlight the heat-treating markets of North America with respect to equipment and processing, comparing current 2014 status and projecting expectations for 2024.