INFRARED SENSING FOR ONLINE WELD GEOMETRY MONITORING AND CONTROL

This paper describes a method for on-line weld geometry monitoring and control using a single front-side infrared sensor. Variations in plat e thickness, shielding gas composition and minor element content are k nown to cause weld geometry changes. These changes in the weld geometr y can be distinctly detected from an analysis of temperature gradients computed from infrared data. Deviations in temperature gradients were used to control the bead width and depth of penetration during the we lding process. The analytical techniques described in this paper have been used to control gas tungsten are and gas metal are welding proces ses.