The Production and Characterization of a Reference Standard Welding Fume. Part Two: The Chemistry of Welding Smoke and Its Variation with Welding Process and Process Parameters

摘要

Welding fume is characterized by analysis of its chemical composition using standard techniques (atom absorption spectroscopy, wet chemistry etc.) combined with Proton Induced X-ray fluorescence spectrosocpy (PIXE). The two methods are compared (based on fume collected on standard paper filters), and the results are used to determine the sources and magnitudes of analysis errors arising from collection techniques, product variation, sample inhomogeneity and measurement and interpretation errors. The hexavalent chromium content of stainless steel welding fume is also studied. It is found that standard analytical methods cannot be used and a specific technique is developed which permits the determination of the Cr(VI) content of both the water soluble and the insoluble welding fume fraction. This general characteristic, coupled to the fact that the relative composition of the fume is a strong function of the welding parameters, is of extreme importance from a hygienic point of view: the choice of values for the welding parameters, processes and materials effects the local ventilation requirements in a significant way. Ultimately both the technical and hygienic points of view can be combined, and used together with the results of a systematic survey of fume chemistry, to provide guidelines for achieving the maximum productivity with the minimum health risk, and optimum investment in ventilation facilities.