Characterization of welding aerosols generated by resistance spot welding.
Afshari-A; Chen-BT; Schwegler-Berry-D; Cumpston-J; Cumpston-CA; Leonard-D; Friend-S; Zeidler-Erdely-PC; Frazer-DG; Antonini-JM
Toxicologist 2011 Mar; 120(Suppl 2):120-121
Resistance spot welding (RSW) is effective for fabricating sheet metal articles when high rates of production are necessary. RSW is commonly used in the automotive, aircraft, and appliance industries where high speed, repetitive welding is needed and relatively thin section sizes are welded. Decreased lung function, metal fume fever, and chronic bronchitis have been observed after exposure to the complex fumes produced by RSW. The goals of the study were to develop a RSW generation and inhalation exposure system that will be used for future animal toxicology investigations and to characterize the aerosols and vapors formed during RSW. The system is divided into three different areas: (1) enclosed spot welder, (2) animal exposure chamber including aerosol/vapor characterization equipment, and (3) computer control room. RSW was performed inside of an enclosure as two strips of low carbon steel (1/32 in. thick, 1 in. wide) were continually fed between two copper alloy electrodes and spot welded every 45 sec at a setting of 760 lbs force and 5000 amps. A real-time aerosol monitor (Data RAM) was used to monitor and maintain a particle mass concentration at 1.4 mg/m3. Particle size distribution and mass median aerodynamic diameter (MMAD) were determined using a Micro- Orifice Uniform Deposit Impactor (MOUDI). Particle morphology and elemental composition were determined by scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX). Analysis of the size distribution indicated the MMAD of the generated particles was approximately 0.94 um with a geometric standard deviation of 2.0. SEM/EDX revealed the RSW aerosol particles to be primarily composed of iron and arranged as chain-like agglomerates that resembled the morphology of typical arc welding fume. Larger, more amorphous particles also were observed among the agglomerates. With the development of this novel RSW system, the potential toxic lung effects of spot welding fume can be examined in an animal model.
Aerosols; Animals; Animal-studies; Engineering-controls; Fumes; Inhalation-studies; Laboratory-animals; Lung; Lung-disease; Lung-disorders; Lung-function; Lung-irritants; Metallic-compounds; Metallic-dusts; Metallic-fumes; Metal-refining; Particle-aerodynamics; Particulates; Particulate-sampling-methods; Pulmonary-disorders; Pulmonary-function; Pulmonary-system; Pulmonary-system-disorders; Respiratory-hypersensitivity; Respiratory-irritants; Respiratory-system-disorders; Vapors; Welding; Welding-industry
The Toxicologist. Society of Toxicology 50th Annual Meeting and ToxExpo, March 6-10, 2011, Washington, DC