Criminalist III, New Orleans Police Department Crime Laboratory, New Orleans, LA
(Received 26 August 1992; accepted 23 November 1992)
During the process of welding metal together, a scale or slag develops over the surface of the weld. This slag is a by-product of the welding process. It is composed of metallic oxides and residue of the fluxing agents present in the welding rods. This scale is normally removed when the weld is completed. If the scale remains on the weld, it will chip off when the weld is struck with a hard object or the weld breaks.
When the inside surface of these pieces of slag are examined, random flow patterns are observed that can be compared to the random weld bead flow patterns on the surface of the weld. These patterns are produced by the pooling of molten metal during the fluxing of work surface metal and the welding rod material. These patterns are produced at random and are unique to each and every welded surface.
The author of this paper is not aware of any literature discussing the examination and comparison of random weld bead flow patterns on welded material. In this case discussed herein, such a comparison was made. Specifically, the author was able to compare these flow patterns on the slag removed from a victim's upper torso with the flow patterns on welded surfaces on a wall decoration.
The results of the comparison concluded positively that the slag was once attached to a welded surface on the wall decoration.
Paper ID: JFS13502J