Video imaging system and thermal mapping of the molten hearth in an electron beam melting furnace

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:387471

Miszkiel, M E; Davis, R A; Van Den Avyle, J A ^[1]

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1. Sandia National Laboratories, Albuquerque, NM (United States); and others

This project was initiated to develop an enhanced video imaging system for the Liquid Metal Processing Laboratory Electron Beam Melting (EB) Furnace at Sandia and to use color video images to map the temperature distribution of the surface of the molten hearth. In a series of test melts, the color output of the video image was calibrated against temperatures measured by an optical pyrometer and CCD camera viewing port above the molten pool. To prevent potential metal vapor deposition onto line-of-sight optical surfaces above the pool, argon backfill was used along with a pinhole aperture to obtain the vide image. The geometry of the optical port to the hearth set the limits for the focus lens and CCD camera`s field of view. Initial melts were completed with the pyrometer and pinhole aperture port in a fixed position. Using commercially available vacuum components, a second flange assembly was constructed to provide flexibility in choosing pyrometer target sights on the hearth and to adjust the field of view for the focus lens/CCD combination. RGB video images processed from the melts verified that red wavelength light captured with the video camera could be calibrated with the optical pyrometer target temperatures and used to generate temperature maps of the hearth surface. Two color ratio thermal mapping using red and green video images, which has theoretical advantages, was less successful due to probable camera non-linearities in the red and green image intensities.

• Research Organization: Sandia National Laboratory
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 387471
• Report Number(s): CONF-951158--
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
DIAGNOSTIC TECHNIQUES
DISPLAY DEVICES
ELECTRON BEAM FURNACES
IMAGES
LIQUID METALS
MAPPING
TEMPERATURE DISTRIBUTION