|
Six welding fumes, representing a variety of welding rods and wires,
were analyzed for particle size and chemistry by X-ray diffraction, energy
dispersive X-ray analysis, scanning transmission electron microscope,
and automated electron beam analysis. Four carbon steel fumes (E6010,
E7018, E70S-3, E70T-1), a stainless steel fume (E308-16) and an aluminum
fume (E5356) were tested. It was found that particle average diameters
are all in the respirable range â?? between 0.1 and 1.0 µM. Few individual
particles were greater than 1 µM, but STEM pictures revealed many particles
as small as 0.01 µM. The particles appeared to be spheres or clusters
of spheres. Even though no crystalline features were observed, all particles
examined produced electron diffraction patterns, indicating that they
contained crystalline material. There was no correlation between average
diameter and particle chemistry or between average diameter and fume type.
An analysis of particle chemistry indicates that the potential toxicity
of the fumes does vary appreciably.
|