AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Effects of Pulse Parameters on Welding Fume Aerosol Size Distribution and Respiratory Deposition
MARCIO BEZERRA, Jun Wang, James Regens, University of Oklahoma
Abstract Number: 709 Working Group: Aerosol Exposure
Abstract Welding fume contains various inhalation toxins such as hexavalent chromium and manganese. Occupational exposure to welding fume can cause various carcinogenic and neurological effects. The high-temperature welding process creates high concentrations of nano- to submicron-sized metallic aerosols composed of toxic metals. Pulse welding targets on reducing the heat input to the welding arc zone by high-frequency voltage fluctuation, in opposed to the steady voltage in non-pulse welding. Pulse welding was hypothesized to improve the weld quality, while decreasing the metal vaporization. The objective of this study is to investigate the pulse parameters (voltage, frequency, and percentage) on formation and characteristics of welding fume aerosols. A pulse metal inert gas welder was placed in a metal fume chamber. Welding with different combinations of pulse parameters as well as baseline (non-pulse) were conducted through beading on 308L stainless steel plates. Particle size distribution was measured by a scanning mobility particle sizer and an aerodynamic particle sizer for fine and coarse particles, respectively. Respiratory deposition fractions for head airways (HA), tracheobronchial (TB), and alveolar (AL) regions were estimated based on a simplified International Commission on Radiological Protection (ICRP) model. The results indicated the dominant parameter of particle emission characteristics was pulse voltage. Pulse welding did not drastically change the geometric distribution of the particle sizes comparing to the non-pulse welding. However, pulse welding reduced the particle emissions in both fine and coarse regimes, without compromising the weld quality. Use low pulse voltage can produce the least particle number concentrations (3.0E7 #/cm3 fine particles and 0.7E4 #/cm3) and in favor of more upper respiratory tract deposition. Hence, we suggest the welder should operate at a low pulse voltage to minimize the potential particle exposures.